BACKGROUND TO THE INVENTION The problem of output shaft rotational motion pulsing can occur in the field of continuously variable transmissions that use one or more clutches operated by reciprocating linkages to transmit rotational motion to an output shaft. These are types of transmissions also referred to as ratcheting transmissions.

In this type of transmission, a prime mover rotates a shaft that is connected to a variable throw reciprocating mechanism. The variable throw reciprocating mechanism transmits rotational motion to a clutch over a predetermined portion of its reciprocating motion by way of a connecting member. Usually a number of clutches are located around an output shaft and caused to grip and release the output shaft sequentially in order to provide continuous shaft rotation.

The clutches act on the output shaft by rotating it in one direction, and releasing it when they are rotated in the opposite direction.

Therefore, in a continuously variable transmission the transmitted rotational motion of the clutches to the output shaft can exhibit a pulsing characteristic, which would be a function of the predetermined portion of reciprocating motion of the reciprocating mechanism that is employed to rotate the clutch. The amount of pulsing is a function of the number of clutches located around the output shaft and the nature of the motion imparted to each clutch by each reciprocating linkage.

Over the years there have been numerous attempts to overcome the problem of pulsing with varying degrees of success. For example, attempts have been made to control pulsing by providing a profiled slot in which an arm with a follower runs with the arm acting on the connecting members. By controlling the movement of the connecting arm the output rotational motion of the clutch is controlled. Problems with this method include that the follower or slot may require continuous realignment for different transmission gear ratios, can experience wear and operate at very high contact pressures. This means that the device is complex and the life of the specific transmission can consequently be short. Other configurations have also been used with varying degrees of success.

Another problem with a continuously variable transmission is changing the ratio of the input motion to the output motion to control the amount of rotation transmitted to the output shaft. Various attempts have been made to provide mechanisms through which the ratio can be changed, with varying degrees of success.

In this specification the term"simple harmonic motion"means a particular characteristic of motion that typically follows a sine wave function. Thus for a horizontal radius link that is rotated about one end from a horizontal position through the vertical and further around to the opposite horizontal position, in a

manner such as that demonstrated by a crank shaft lobe during crankshaft rotation, the outer end of such a radius link will generate a sine wave motion if such outer end is projected perpendicularly onto the horizontal for all angles of rotation. The first portion of a sine wave curve when considered up to the midway position is a mirror image of the second portion of the curve.

In this specification the term"gear ratio"of a continuously variable transmission means the number of revolutions, x, of an input shaft required to produce one complete revolution of an output shaft. It is typically referred to as the ratio x : 1.

In this specification the tenn"flatline"means a modified sine wave function motion. For flatline motion the normal sine wave shape has its maximum crest point flattened and its initial rising slope and final falling slope steepened. This results in the curve rising more steeply and then flattening out at a pre-selected point prior to its normal maximum. The flattened portion is then extended until the same pre-selected point is encountered on the falling side of the curve at which point the modified sine wave is caused to more steeply fall until the zero point is reached. The first portion of the curve when considered up to the midway position is a mirror image of the second portion of the curve. The amount of flatline is defined as one that produces a maximum variation of no more than 1,5% in any transmitted gear ratio in the operating range utilised to rotate the output shaft.

OBJECT OF THE INVENTION It is an object of this invention to provide a flatline device, a ratio change device, for use the flatline and ratio change devices in a continuously variable transmission that at least partly alleviates the above-mentioned problems.

SUMMARY OF THE INVENTION In accordance with this invention there is provided a first flatlining device including input and modifying arms; the modifying arm being sliding and rotatably connected at a first end thereof to the input arm; the input arm having a point of rotation intermediate first and second ends thereof and being rotatably connected at a connection point to a simple harmonic reciprocating motion generator which produces simple harmonic reciprocating motion along a plane ; the modifying arm having a point of rotation intermediate first and second ends thereof and the input arm rotation point and the input arm connection point being non-coincidental ; the input arm being at least partly rotatable around the input arm rotation point by input motion from the motion generator, and the modifying arm being at least partly rotatable around the modifying arm rotation point by means of the sliding connection with the input arm; the motion transfer from the input arm to the modifying arm modifying the rotational velocity profile of the input motion transferred to the modifying arm by increasing the rotational velocity of the modifying arm in at least part of the velocity profile, the modifying arm thereby having a rotational reciprocating motion with a modified velocity profile over a predetermined sweep angle.

There is further provided for the input arm and the simple harmonic reciprocating motion generator to be rotatably and sliding connected.

The invention further provides for a second flatlining device including a drive disc, a return disc, drive link, and endless belt, and two idler rollers ; the drive disc being securable to an input shaft, the return disc being rotatably locatable around the input shaft, the drive link being rotatably secured at a first end to a boss and the boss being rotatably securable around the input shaft,

the drive link being located intermediate the drive disc and the return disc, and each idler roller being rotatably secured around a stationary axis of rotation radially orientated to the input shaft at some predetermined rotational angle with respect to each other and intermediate the drive and return discs; the drive disc and return disc having opposing faces with slots therein arranged to cooperate with a second end of the drive link, the second end of the drive link being rotatably connected to the endless belt and the endless belt having a series of protrusions arranged to cooperate with the slots on the opposing faces of the drive and return discs; the endless belt being located around the two rollers and engaging with the slots in the opposing faces of the drive and return discs; whereupon rotation of the input shaft the drive disc is equally rotated, the rotation is transmitted to the endless belt by means of the protrusions of the endless belt engaging with the slotted face of the drive disc, the endless belt in turn rotates the return disc around the input shaft in the opposite direction of rotation to the input shaft, and the second end of the drive link engages with a slot in one of the drive or return discs to be rotated around the input shaft with the endless belt, the drive link thereby following the input shaft direction of rotation when it engages a slot in the drive disc slotted face and the opposite direction of rotation when it engages a slot in the return slotted face, the rotational speed of the drive link second end matching the rotational speed of the input shaft in either direction of its rotation, the drive link second end thereby delivering flatline output rotational speed that includes a portion of acceleration when the second end travels around a first of the two rollers, a portion of constant rotational speed when the second end engages the slotted face of the drive disc to be rotated together, a portion of deceleration when the second end disengages from the drive disc by moving from the drive disc towards the second roller, a portion of acceleration in the opposite direction of rotation when the second end moves from the second roller towards engagement with slotted face of the return disc, a portion constant rotational

speed when the second end engages the slotted face of the return disc to be rotated together, and a portion of deceleration when the second end disengages from the return disc by moving from the return disc towards the first roller thereby completing one cycle of rotation of the second end.

There is further provided for the second end to be located within a slot in a frame that is located at a radius from the input shaft greater than the drive disc and return disc radii, the frame including at least one arm that is rotatably securable to the input shaft; the frame being rotatable around the input shaft in response to the flatline motion of the second end around the input shaft.

There is still further provided for the rollers to have geared bearing surfaces cooperating with the endless belt protrusions to enable torque transmission from the drive disc to the return disc.

The invention also provides for a first ratio change device comprising an input arm, a cross slide, and a ratio beam; the input arm having flatline reciprocating input motion around an input arm point of rotation located intermediate first and second end of the input arm, the input arm second end being the reciprocating end, and the input arm second end being sliding connected to a first saddle bearing and the first saddle bearing being pivotally connected to the cross slide ; the cross slide being sliding located within a sliding way having an sliding axis that is adjustable relative to the input arm point of rotation; the ratio beam having first and second ends, the first end being sliding connected to a second saddle bearing, the second saddle bearing being sliding connected to the cross slide, the first and second saddle bearings having the same pivot centre on the cross slide, the ratio beam including a pivot centre intermediate the ratio beam first and second ends, and the ratio beam pivot centre and the input arm point of rotation being located on a plane perpendicular to the cross slide sliding axis;

whereby reciprocating motion of the input arm second end is transferred through the cross slide to the ratio beam, and adjustment of the cross slide sliding axis relative to the input arm point of rotation causes the ratio of the reciprocating motion transferred from the input arm to the ratio beam to be changed, the ratio beam thereby having a ratio adjusted reciprocating motion about the ratio beam pivot centre.

There is further provided for the ratio of the distance between the input arm rotation point and the ratio beam rotation point and the distance between the input arm rotation point and the cross slide axis plane to be adjustable to minimize pulsing in any selected gear ratio.

A further feature of the invention also provides for a second ratio change device comprising an input arm, a radial link, and a ratio beam; the input arm having flatline reciprocating input motion around an input arm point of rotation located intermediate first and second end of the input arm, the input arm second end being the reciprocating end, and the input arm second end being sliding connected to a first saddle bearing and the first saddle bearing being pivotally connected to a first end of the radial link ; the radial link having a point of rotation proximate a second end of the radial link, the radial link point of rotation being adjustable relative to the input arm point of rotation; the ratio beam having first and second ends, the first end being sliding connected to a second saddle bearing, the second saddle bearing being pivotally connected to the radial link first end, the first and second saddle bearings having the same pivot centre on the radial link first end, the ratio beam including a pivot centre intermediate the ratio beam first and second ends, and the ratio beam pivot centre and the input arm point of rotation and the radial link point of rotation being located on a single plane ; whereby reciprocating motion of the input arm second end is transferred through the radial link to the ratio beam, and adjustment of the radial link point

of rotation relative to the input arm point of rotation causes the ratio of the reciprocating motion transferred from the input arm to the ratio beam to be changed, the ratio beam thereby having a ratio adjusted reciprocating motion about the ratio beam pivot centre.

There is further provided for the ratio of the distance between the input arm rotation point and the ratio beam rotation point and the distance between the input arm rotation point and the radial link first end to be adjustable to minimize pulsing in any selected gear ratio.

A still further feature of the invention provides for a combined flatlining and ratio change device comprising input and modifying arms; the modifying arm being sliding and pivotally connected at a first end thereof to the input arm; the input arm having a point of rotation and being rotatably connected at a connection point to a simple harmonic reciprocating motion generator, with the input arm rotation point and the input arm connection point being non-coincidental ; and the modifying arm having a point of rotation intermediate first and second ends thereof; the input arm being at least partly rotatable around the input arm rotation point by input motion from the motion generator, and the modifying arm being at least partly rotatable around the modifying arm rotation point by means of the sliding connection with the input arm; the motion transfer from the input arm to the modifying arm modifying the rotational velocity profile of the input motion transferred to the modifying arm to a flatline velocity profile.

There is further provided for the input arm rotation point to be located intermediate first and a second ends of the input arm, and for the input arm connection point to be located at a first end of the input arm.

There is still further provided for the distance between the input arm connection point and the input arm rotation point to be adjustable and for the distance between the input arm point of rotation and the modifying arm point of rotation

to be adjustable, and for adjustment of these distances to cause a change in the ratio of the reciprocating motion transferred from the input arm to the modifying arm, the modifying arm thereby having a ratio adjusted reciprocating motion about the modifying arm point of rotation.

There is also provided for the sliding and pivotal connection between the input arm and modification arm and the modifying arm and the ratio beam respectively, to be operatively arranged to prevent frictional lockup by configuration of the angle of incidence between the input arm and modifying arm and the modifying arm and ratio change beam, to allow a sliding connection between the input arm and modifying arm at the sliding connection.

There is further provided for the configuration of the angle of incidence of the sliding and pivotal connection between the input arm and modifying arm and the modifying arm and ratio change beam respectively, to take into account the forces acting through the input arm and modifying arm at the sliding connection and the coefficient of friction of the sliding surfaces.

There is still further provided for the input arm rotational point to include a pin rotatably supported by two bearings; for one end of the pivot to extend through the bearings, and for the input arm to be rotatably connected to the extended end of the pivot; for the modifying arm rotational point to include a pin rotatably supported by two bearings; for one end of the pivot to extend through the bearings, and for the modifying arm to be rotatably connected to the extended end of the pivot; and for the ratio beam rotational point to include a pin rotatably supported by two bearings; for one end of the pivot to extend through the bearings, and for the ratio beam to be rotatably connected to the extended end of the pivot.

The invention also provides for each sliding connection between arms or links to comprise a slider pivotally connected to one arm or link and, for the slider to

include a base with a plurality of slots therein, and for the arm or link to include a base with a plurality of complimentary ribs, and for the ribs to be sliding receivable within the slots.

The invention also provides for each pivotal connection between arms or links to comprise two cooperating bases, each base having a series of concentric ribs extending from the base with a series of concentric slots between the ribs, the concentric ribs of one base being sliding receivable within the slots of the other base, thereby forming a plurality of bearing surfaces for rotation of the one base relative to the other.

There is further provided for the motion generator to receive rotational input motion from an input shaft, and for the input shaft to be driven by or integral with a prime mover.

According to a further feature of the invention there is provided a first continuously variable transmission comprising any one of the first or second flatlining devices in combination with any one of the first or second ratio change devices, and at least one clutch locatable around an output shaft; the second end of the ratio beam being rotatably connected to a first end of a cross link, and the cross link being rotatably connected to the clutch ; the clutch having an operating cycle in which the clutch is adapted to grip the output shaft when the clutch is rotated in one direction and to release the output shaft when the clutch is rotated in the opposite direction; the reciprocating output motion of the ratio beam second end thereby sequentially rotating the clutch in the one direction and then the opposite direction to rotate the output shaft in the one direction.

According to a yet further feature of the invention there is provided a second continuously variable transmission comprising the combined flatlining and ratio change device, and at least one clutch locatable around an output shaft;

the second end of the modifying arm being rotatably connected to a first end of a cross link, and the cross link being rotatably connected to the clutch ; the clutch having an operating cycle in which the clutch is adapted to grip the output shaft when the clutch is rotated in one direction and to release the output shaft when the clutch is rotated in the opposite direction; the reciprocating output motion of the ratio beam second end thereby sequentially rotating the clutch in the one direction and then the opposite direction to rotate the output shaft in the one direction.

There is also provided for the ratio beam second end of the first continuously variable transmission and the modifying arm second end of the second continuously variable transmission to be rotatably connected to a second cross link, and for the second cross link to be rotatably connected to a second clutch locatable around a second output shaft thereby forming a double set of clutches with two output shafts; for the first clutch to operatively rotate its associated first output shaft and for the second clutch to operatively release the second output shaft when the modifying arm is rotated in the first direction; and for the first clutch to operatively release the first output shaft and for the second clutch to operatively rotate the second output shaft when the modifying arm is rotated in the second direction.

There is still further provided for the first and second output shafts to be meshed together by means of a gearing arrangement, and for one of the output shafts to be employed as a final output shaft and to be rotated in a predetermined direction of rotation through the gearing arrangement or altematively for both output shafts to be suitably meshed to a separate final output shaft by means of a gearing arrangement and for the final output shaft to be rotated in a predetermined direction through the gearing arrangement.

There is also provided for each continuously variable transmission to include at least two, preferably six, flatlining and ratio change devices ; for each flatlining

and ratio change device to transmit reciprocating output motion to one clutch ; for each clutch to operatively rotate the output shaft, the reciprocating input motion of the flatlining devices being timed to rotate the clutches sequentially to produce substantially smooth output rotation of a driven shaft.

There is further provided for the continuously variable transmission with six flatlining and ratio change devices to be arranged such that the inertia energy of each clutch together with its operating linkage comprising input arm and modifying arm to be balanced by substantially simultaneous acceleration and deceleration of different clutch and operating linkage simple harmonic modifying devices; and for the transmission to be suitably arranged such that at any given time one simple harmonic modifying device is producing a substantially constant rotational velocity output motion, another simple harmonic modifying device is producing substantially constant return rotational velocity for the non gripping clutch, two simple harmonic modifying devices are being accelerated, and two simple harmonic modifying devices are being decelerated to substantially the same degree such that at all times the overall inertial energy demand required to operate the overall arrangement is comparatively low when compared to the inertia energy demand required to operate a single simple harmonic modifying device.

There is also provided for the continuously variable transmission to include at least two, preferably three, flatlining and ratio change devices; for each ratio change device to transmit reciprocating output motion to a set of two clutches ; for the first clutch of each set of clutches to operatively rotate the first output shaft, and for the second clutch of each set of clutches to operatively rotate the second output shaft; and the reciprocating input motion of the flatlining devices timed to rotate the clutches sequentially to produce substantially smooth output rotation of a driven shaft.

There is further provided for the inertia energy of each set of two clutches together with their operating linkages comprising input arm and modifying arm to be balanced by substantially simultaneous acceleration and deceleration of different sets of two clutches together with their operating linkages simple harmonic modifying devices; and for the transmission to be suitably arranged such that at any given time one simple harmonic modifying device is producing a substantially constant rotational velocity output motion, a second simple harmonic modifying device is being accelerated, and the third simple harmonic modifying device is being decelerated to substantially the same degree such that at all times the overall inertia energy demand required to operate the overall arrangement is comparatively low or zero when compared to the inertia energy demand required to operate a single simple harmonic modifying device.

There is still further provided for the continuously variable transmission to include a counterbalancing shaft rotationally connected to the input shaft, and the counterbalancing shaft to include at least one predetermined counterweight to balance any mechanical vibrations generated by the device.

There is still further provided for the continuously variable transmission to include end pivoting any arm or link such that action imparted to one end is equally imparted from that same end thereby effectively facilitating rotational pivoting about one end only thereby effecting space saving practical linkage orientation.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will be described below by way of example only and with reference to the accompanying drawings and tables in which : Figure 1 is a graphical representation of a first embodiment of a flatlined motion device;

Figure 2 is a graphical representation of a second embodiment of a flatlined motion device; Figures 3a and 3b are graphical representations of a third embodiment of a flatlined motion device; Figure 4 is a graphical representation of a first embodiment of a ratio changing device ; Table 1 shows an example of the effectiveness of input motion modification utilising the embodiments shown in Figures 1 and 4 in a system employing four operating linkages and four output clutches operating on an output shaft; Figure 5 is a graphical representation of a second embodiment of a ratio changing device; Figure 6 is a graphical representation of a third embodiment of a ratio changing device; Figure 7 is a graphical representation of the simple harmonic reciprocating input motion generated by a simple harmonic motion generator; Figure 8 is a graphical representation of the result that would be achieved by staging the simple harmonic input motion of four clutches onto an output shaft, showing the resultant rotational velocity profile of the output shaft and the pulsing in the output shaft rotational velocity profile that would be experienced;

Figure 9 is a graphical representation of the velocity profile modification, showing a stage in which constant velocity is maintained, the so- called flatlined portion; Figure 10 is a graphical representation of the result of operating four clutches, which receive input motion that has been modified as in Figure 9, onto one output shaft. It shows the resultant flatlined velocity profile of the output shaft.

Figures 11 a and 11 b are diagrammatical representations of the velocity profile modification for flatlining used in the embodiment shown in Figure 1; Figures 12a and 12b are diagrammatical representations of the velocity profile modification used in the embodiment shown in Figure 2 Figure 13a is a perspective view of a sliding connector with base and slots pivotally connected to a first end of a modifying arm and engaging an input arm constructed with base and suitably matching protrusions employed as in the first and second embodiments shown in Figures 1 and 2.

Figures 13b and 13c are different views of the sliding connector shown in Figure 13a.

Figure 14a is a perspective view of a rotational connector pivot with base and circular ring protrusions and slots pivotally connected to a first end of a first link and engaging a second link constructed with base and suitably matching circular protrusions employed as in any rotatable connection.

Figures 14b and 14c are different views of the rotational connector pivot shown in Figure 14a.

Figure 15 is a diagrammatical representation of the input arm and modifying arm rotation point configuration for all embodiments, showing the cantilever pin and rotational bearing arrangement facilitating reciprocating rotational motion in which one arm is enabled to pass over the other without mechanical interference.

Figure 16 is a schematic representation of a further embodiment of a continuously variable transmission according to the invention in which two clutches each acting upon a discrete output shaft are rotationally reciprocated by one output linkage and both output shafts are geared together; Figure 17 is a graphical representation of the continuous output shaft flatline transmission and the inertia interaction of a further embodiment showing in which 3 linkages operate 6 clutches sequentially on two output shafts; Figure 17a is a graphical representation of a further embodiment showing the continuous output shaft flatline transmission and the inertial interaction between 6 linkages that operate 6 clutches sequentially on one output shaft for any embodiment Figure 18 is a schematic representation of a further embodiment of a continuously variable transmission according to the invention showing a space saving end pivoted link typical arrangement of input arm in Figure 2;

Figure 19 is a schematic representation of a further embodiment of a continuously variable transmission according to the invention indicating utilisation of end pivoting of ratio beam in Figure 19 and the resultant space saving advantage such space saving practise being relevant to all embodiments; DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE DRAWINGS In the embodiments of continuously variable transmissions according to invention described below rotational input motion from a prime mover is transmitted through a continuously variable transmission to a final output shaft.

The continuously variable transmission utilizes several one-way clutches to sequentially grip and rotate the output shaft.

An important aspect of the continuously variable transmission when the first and second flatlined motion embodiments are employed is that the rotational input motion from the prime mover is converted into linear or semi linear motion of a cross slide member which is in turn converted into reciprocating rotational motion of a modifying arm which is used as the input motion for any of the three gear ratio changing embodiments of the transmission that reciprocate the drive clutches acting upon the output shaft.

The linear or semi linear motion derived from the rotational input motion is simple harmonic motion, as already defined in the specification. The velocity profile of simple harmonic motion can be described as a sine wave profile. This is shown in Figure 7, where the velocity (V) of the input arm is plotted as a function of the angular displacement (p) of the input shaft. It can be seen that at 0 degrees rotation the velocity is zero (Vzero) The velocity increases between 0 and 90 degrees to reach a maximum (Vmax) at 90 degrees. Thereafter the velocity decreases up to 180 degrees where it reaches zero (Vzero) again. This

portion between 0 and 180 degrees is the forward stroke. The forward stroke therefore includes an acceleration portion (0 to 90 degrees) and a deceleration portion (90 to 180 degrees).

The forward stroke is followed by a backstroke of the input arm. This is shown in Figure 7 as the portion between 180 and 360 degrees. Similar to the forward stroke there is an initial acceleration followed by a deceleration portion in the backstroke. This is shown as negative in Figure 7 because the input arm is busy with the backstroke between 180 and 360 degrees. Similar to the forward stroke the input arm reaches a maximum velocity in the backstroke at 270 degrees.

If a cross slide exhibiting a simple harmonic motion velocity profile is connected by a suitable rotational pivot and or slidable connection to a rotatable arm at a first end of such arm it is possible for the arm to be reciprocated rotationally. It is further possible to transmit the simple harmonic rotational reciprocating motion of the arm directly to an output shaft by means of an actuated or one- way clutch.

However, even if a number of one-way clutches are employed to sequentially grip and release the output shaft the resultant velocity profile of the output shaft will still include a substantial amount of pulsing. Effectively a number of velocity profiles are superimposed out of phase over each other. For example : with four clutches the clutches will have to be sequentially 90 degrees out of phase from each other in order to provide continuous rotation of the output shaft.

Superimposing the peaks of four simple harmonic motion velocity profiles onto each other gives an indication of the resulting rotational velocity profile of the output shaft. This is shown in Figure 8.

The resultant rotational velocity profile is shown as a separate line (1) above the four individual velocity profiles (2). It can be seen there is still a substantial

amount of deceleration and acceleration that takes place between the take over from one clutch to the next. This is defined as the pulsing in such a system.

Even a fairly small percentage of pulsing in a transmission is unacceptable from a performance and reliability point of view and it is therefore not a preferable option to merely connect the simple harmonic reciprocating input motion to the actuated or one-way clutch.

It is therefore essential that the pulsing be removed before the input motion is transmitted through the transmission to the output shaft. The effect of modifying the input motion to remove pulsing from it is shown in Figure 9. In this drawing the forward stroke of the input arm is shown, that is the portion between 0 and 180 degrees. A comparison with the same portion in Figure 7 clearly shows the difference between the two profiles. As shown in Figure 9, there is a portion from about 45 to 135 degrees where the velocity of the input arm has been modified to be constant. This is defined as the so-called flatline area of the velocity profile and is produced by a flatline linkage.

The acceleration between 0 and about 35 degrees is higher for the profile shown in Figure 9 than the profile shown in Figure 7 due to the fact that the maximum velocity (Vmax) is reached at 45 degrees instead of 90 degrees.

Similarly, the deceleration from 135 to 180 degrees is higher because the arm has to be decelerated from the maximum velocity (Vmax) to zero in about 35 degrees rotation instead of 45 (90) degrees.

The effect of the flatline input motion on the final output shaft motion is shown in Figure 10. This is similar to Figure 8, the only difference being that the input motion of the four clutches includes flatline portions as shown in Figure 9. The resultant output shaft velocity profile is shown as line (3) in Figure 10.

It can be seen that each clutch only transfers rotational motion to the output shaft during its portion of constant rotational velocity, or its so-called flatline phase. The result is a constant flat-line rotational velocity profile of the output shaft.

There are numerous ways in which flatline motion of the clutches can be achieved but the applicant has found that there are a few ways that work better than others.

A first embodiment of a flatline linkage (11) that uses one method of flat-lining input motion is shown in Figure 1. The flatline linkage device (11) includes a first member which is a reciprocating arm (20), and a second member which is a correcting link (24).

Input motion for the flatline linkage (11) is supplied by a reciprocating motion generating device, which includes an input crank shaft (15), that, when rotated, produces a linear reciprocating simple harmonic motion through the action of its throw about its axial centre of rotation. This action is imparted to a simple harmonic motion cross slide (16) by means of a crank big end bearing slider block (17).

The simple harmonic motion cross slide (16) is constrained to reciprocate in a linear manner only by suitably arranged slider bearings (18). The motion generated by this action is along a plane of reciprocation (23).

One end (16a) of the simple harmonic motion cross slide (16) is pivotally connected to a reciprocating arm slider saddle bearing (19) which in turn is mounted in suitably arranged sliding connection onto a first end (20a) of the reciprocating arm (20). The reciprocating arm (20) is rotatably secured at a first rotation point which is a pivot axis (21) and is incorporated into the length of the reciprocating arm (20). The pivot axis (21) is suitably positioned to facilitate

symmetrical rotational reciprocation about a suitably positioned plane (22) situated perpendicular to the plane of linear reciprocation (23).

The correcting link (24) is rotatably secured at a second point of rotation which is a correcting link pivot axis (25) and is located between first end (24a) and second end (24b) of the correcting link (24) and is incorporated into the length of the correcting link (24). The correcting link (24) is suitably arranged to pivot around the correcting link pivot axis (25) and suitably positioned to facilitate symmetrical rotational reciprocation of the correcting link (24) about plane (22).

The correcting link pivot axis (25) is suitably arranged to enable it to be continuously adjustably positioned along plane (22) by means not shown in order to facilitate the selection of suitable flatline rotational reciprocating motion imparted to the correcting link (24) by the reciprocating arm (20) for any ratio selected in the ratio changing device operated by this flatlined linkage device embodiment of the invention, as described in the first and second ratio changing device embodiment descriptions detailed elsewhere in this document.

A correcting link slider saddle bearing (26) is pivotally connected to a suitably determined fixed position (24c) at a first end (24a) of the correcting link (24) and is also suitably mounted in sliding connection onto a second end (20b) of the reciprocating arm (20). Thus the correcting arm (24) has rotational reciprocating motion imparted to it by means of the action of the correcting arm saddle bearing (26) under the influence of rotational reciprocating motion of the reciprocating arm (20).

The second end (24b) of the correcting link (24) is sliding and rotatably connected to ratio adjustment means as described in the first, second and third ratio changing device embodiment descriptions detailed elsewhere in this document.

The modification of the simple harmonic input motion is diagrammatically shown in Figures 11 a and 11b. Figure 11b is a representation of the simple harmonic motion generated by a crankshaft lobe and its corresponding angular linear displacement plotted on the x-plane. As can be seen from points 1 to 9 on the x-plane there is an initial increase in linear displacement between points 1 and 5, which corresponds to the change of velocity of the reciprocating arm (20) as a consequence of the imparted reciprocating motion of the simple harmonic cross slide (16), (not shown in Figures 11a and 11b). At point 5 the maximum speed is reached and thereafter, between points 5 and 9, the linear displacements decrease in size which corresponds to a reduction in reciprocating rotational velocity of the reciprocating arm (20).

Figure 11a shows the linked motion between the reciprocating arm (20) and correcting link (24). The reciprocating arm (20) rotates about the reciprocating arm pivot point (21) and the correcting link (24) about the correcting link pivot point (25). The reciprocating arm (20) and correcting link (24) are linked with the sliding connector (26), (not shown in Figures 11a and 11b). The sliding action of the sliding connector (26) forces the correcting link to follow the motion imparted to it by the reciprocating arm, modifying its reciprocating rotational velocity profile accordingly. The reciprocating rotational velocity of the correcting link (24) is represented by curve (42) in Figure 11a.

A comparison of curve (42) and line (43) shows that for the simple harmonic velocity profile of the reciprocating arm (20) as represented by line (43) the distances between points 3 to 4 and 4 to 5 are substantially different as opposed to the same distances on curve (42) where they are substantially similar. Because the angular displacements on curve (42), between points 3 to 4 and 4 to 5, are substantially the same there is constant angular velocity of the correcting link (24) at these positions. The same applies for the distances 5 to 6 and 6 to 7. The result is that between points 3 and 7 there is constant reciprocating rotational angular velocity, referred to as a flatline rotational

velocity, of the correcting link (24). This corresponds to the rotational distance from A to B of the input crankshaft in Figure 11b, which is equivalent to about 90 degrees of rotation of the input shaft.

A second embodiment of a flatline linkage (12) uses one method of flat-lining input motion as shown in Figure 2. The flatline linkage (12) includes a motion modifying device that comprises a first member which is a reciprocating arm (20), and a second member which is a correcting link (24).

Input motion for the flatline linkage (12) is supplied by a reciprocating motion generating device, which includes an input crank shaft (15), that, when rotated, produces a linear reciprocating simple harmonic motion through the action of its throw about its axial centre of rotation. This action is imparted to a simple harmonic motion cross link (16) by means of a crank big end bearing slider block (17).

The simple harmonic motion cross link (16) is pivotally connected to and constrained to reciprocate about the reciprocating arm (20) and rocker arm (20c) arranged in such manner that reciprocating arm (20) and rocker arm (20c) exhibit a parallelogram motion together with cross link (16).

One end (16a) of the simple harmonic motion cross link (16) is pivotally connected to a first end (20a) of the reciprocating arm (20). A second end (16b) of the cross link (16) is pivotally connected to a first end (20d) of a rocker arm (20c). The reciprocating arm (20) is rotatably secured at a first rotation point which is a reciprocating arm pivot axis (21) and is incorporated into the length of the reciprocating arm (20). The pivot axis (21) is suitably positioned to facilitate symmetrical rotational reciprocation about a suitably positioned plane (22) situated perpendicular to plane (23a) formed by the mutual alignment of reciprocating arm (20) pivot (21) and rocker arm (20c) pivot (20e). The rocker arm (20c) is rotatably secured at a first point of rotation which is a rocker arm

pivot axis (20e) and is situated at a second end (20f) of the rocker arm (20c) and positioned on plane (23a).

The correcting link (24) is rotatably secured at a suitable point of rotation which is a correcting link pivot axis (25) and is located between first end (24a) and second end (24b) of the correcting link (24) and is incorporated into the length of the correcting link (24). The correcting link (24) is suitably arranged to pivot around the correcting link pivot axis (25) and suitably positioned to facilitate symmetrical rotational reciprocation of the correcting link (24) about plane (22).

The correcting link pivot axis (25) is further suitably arranged to enable it to be continuously adjustably positioned along plane (22) by means not shown in order to facilitate the selection of suitable rotational reciprocating motion imparted to the correcting link (24) by the reciprocating arm (20) for any ratio selected in the ratio changing device operated by this flatlined linkage device embodiment of the invention, as described in the first and second ratio changing device embodiment descriptions detailed elsewhere in this document.

A correcting link slider saddle bearing (26) is pivotally connected to a suitably determined fixed position (24c) at a first end (24a) of the correcting link (24) and is also suitably mounted in sliding connection onto a second end (20b) of the reciprocating arm (20). Thus the correcting arm (24) has rotational reciprocating motion imparted to it by means of the action of the correcting arm saddle bearing (26) under the influence of rotational reciprocating motion of the reciprocating arm (20).

The second end (24b) of the correcting link (24) is sliding and rotatably connected to ratio adjustment means as described in the first, second and third ratio changing device embodiment descriptions detailed elsewhere in this document.

The modification of the simple harmonic input motion of the second flatline linkage embodiment as shown in Figure 2 is diagrammatically shown in Figures 12a and 12b. Figure 12P is a representation of the simple harmonic motion generated by a crankshaft lobe and its corresponding angular linear displacement plotted on the x-plane. As can be seen from points 1 to 9 on the x-plane there is an initial increase in linear displacement between points 1 and 5, which corresponds to the change of velocity of the reciprocating arm (20) by the reciprocating motion of the simple harmonic cross link (16), (not shown in Figures 12a and 12b). At point 5 the maximum speed is reached and thereafter, between points 5 and 9, the linear displacements decrease in size which corresponds to a reduction in reciprocating rotational velocity of the reciprocating arm (20).

Figure 12a shows the linked motion between the reciprocating arm (20) and correcting link (24). The reciprocating arm (20) rotates about the reciprocating arm pivot point (21) and the correcting link (24) about the correcting link pivot point (25). The reciprocating arm (20) and correcting link (24) are linked with the sliding connector (26), (not shown in Figures 12a and 12b). The sliding action of the sliding connector (26) forces the second member to follow the motion imparted by the first member, modifying its reciprocating rotational velocity profile accordingly. The reciprocating rotational velocity of the correcting link (24) is represented by curve (42) in Figure 12a.

A comparison of curve (42) and curve (43) shows that for the simple harmonic velocity profile of the reciprocating arm (20) as represented by line (43) the distances between points 3 to 4 and 4 to 5 are (is) substantially different as opposed to the same distances on curve (42) where they are substantially similar. Because the angular displacements on curve (42), between points 3 to 4 and 4 to 5, are substantially the same there is constant angular velocity of the correcting link (24) at these positions. The same applies for the distances 5 to 6 and 6 to 7. The result is that between points 3 and 7 there is constant

reciprocating rotational angular velocity referred to as flatline velocity, of the correcting link (24). This corresponds to the rotational distance from A to B of the input crankshaft in Figure 12b, which is equivalent to about 90 degrees of rotation of the input shaft.

A third embodiment of a flatline linkage (13) uses one method of flat-lining input motion as shown in Figures 3a, 3b and 3c.

In the third embodiment there is provided a rotational input shaft (100) secured by suitable bearings (not shown) to be rotatable at a suitably predetermined speed such input shaft (100) having a drive disc (101) rigidly mounted to it such that the drive disc (101) rotates as one concentrically with the shaft (100); a second disc, a return disc (102), is rotatably mounted about the shaft (100) at some suitable axial distance along the shaft (100) and adjacent to the drive disc (101) such that it is free to be rotated about the shaft (100.

A drive link (103) of suitable length is further arranged by means of a suitable boss (104) to be rotatably mounted about the shaft (100) between the drive disc (101) and the return disc (102); the drive link (103) being in turn rotatably mounted to its boss (104) at a suitable pivot (105) such combined rotational mountings being arranged to facilitate rotation of the drive link (103) radially along and around the axis (106) of the shaft (100) such that it can suitably engage with matching protrusions or slots (107) incorporated into the contact face of the drive disc (101) and the return disc (102).

This engagement with the drive disc (101) enables drive torque to be transmitted directly to the drive link (103) from the drive disc (101) which is in turn driven by the input shaft (100); the drive link (103) being suitably rotatably connected to at one point to a continuous positioning belt, rope or chain (108) so arranged to convey the drive link (103) over suitably positioned idler pulleys (109,110) mounted on stationary axiis of rotation (111,112) appropriately

arranged at a predetermined angular circumferential spacing radially from the shaft axis (106) between the drive disc (101) and the return disc (102); The positioning belt, rope or chain (108) is driven by mutual engagement through means of suitable protrusions (not shown) with the drive disc (101;) such positioning belt, rope of chain being further arranged to counter rotate the return disc (102) through mutually engaging contact with similar to that for the drive disc (101); both drive disc (101) and return disc (102) being mutually engaged with the positioning belt, rope or chain on each side of the pulleys (109,110).

Through this motion drive link (103) is conveyed rotationally in engagement with the drive disc (101) as it rotates with the shaft (100), disengaging the drive link (103) from the drive disc (101) at a first pulley (109), conveying the drive link (103) around the first pulley (109) to engagement with the return disc (102), rotating in reverse direction with the return disc (102), disengaging the drive link (103) from the return disc (102) at a second pulley (110), conveying the drive link (103) around the second pulley (110) to re-engagement with the drive disc (101) to repeat the cycle.

This action is suitably arranged to impart for a constant input shaft (100) rotational velocity, constant angular rotational velocity referred to as flatline velocity to the drive link (103) when it is engaged with the drive disc (101) and an equal but reverse flatline velocity when the drive link (103) is engaged with the return disc (102); the drive link (103) being further arranged to engage a slot (113) mounted outside the diameter of the drive and return discs (101,102) and axially aligned with the shaft (100).

The slot (113) enables the drive link (103) to slide from engagement with the drive disc (101) to engagement with the return disc (102) while retaining engagement in the slot (113); the slot (113) being incorporated into an axially

aligned arm (113a) arranged at a suitable radial distance greater than that of the drive and return discs (101,102) to be parallel to the shaft (100). The arm (113a) is in turn mounted rigidly upon radial arms (114a, 114b) rotatably mounted about the shaft (100) adjacent to and axially outside the drive disc (101) and the return disc (102) respectively such that the drive link (103) imparts a constant rotational velocity to the radial arms (114a, 114b) when engaged with the drive disc (101) and imparts an equal but reverse constant rotational velocity to the radial arms (114a, 114b) when engaged with the return disc (102).

Furthermore the drive link (103) imparts simple harmonic motion to the radial arms (114a, 114b) when it is conveyed around each pulley (109,110). The radial arms (114a, 114b) thereby exhibits constant rotational velocity firstly in one direction of rotation, simple harmonic motion deceleration to standstill and acceleration to an equal but opposite speed of rotation, and constant rotational velocity secondly in the other direction of rotation about the shaft (100); simple harmonic motion deceleration to standstill and acceleration to the first rotational constant velocity once again to repeat the cycle.

Such rotational reciprocating motion over a predetermined sweep angle being flatlined velocity and enabling the radial arms (114a, 114b) thereby to be used in a manner identical to that of the correcting link (24) referred to in Figures 1 and 2 to provide flatline velocity motion as appropriately required.

In a further embodiment of the invention, idler pulleys (110,109) are arranged to incorporate gear teeth such that torque can be transmitted from the drive disc (101) to the return disc (102). By such means drive link (103) can be utilised to impart torque to radial arms (114a, 114b) when drive link (103) is engaged with either drive disc (101) or return disc (102).

A first embodiment of a ratio changing device is shown in Figure 4. This ratio changing device utilises a reciprocating rotational input motion arm from any one of the three flatline linkage device embodiments previously described and shown in Figures 1,2 and 3. Such input motion arm is respectively referred to as correcting link (24) in Figures 1 and 2 and radial arms (114a, 114b) in Figure 3. Such motion, as previously described, exhibits flatline reciprocating rotational motion. In this embodiment the input motion arm is referred to as correcting link (24).

In this embodiment of the invention the correcting link (24) second end (24b) is sliding connected to a saddle bearing (52) that is in turn pivotally connected to a cross slide (53).

Cross slide (53) is suitably located to facilitate reciprocation along axis (54) by suitably arranged slider way (55). Cross slide (53) is caused to reciprocate along axis (54) which is suitably arranged to be substantially perpendicular to plane (22) by the rotational reciprocating motion of the correcting link (24) second end (24b).

Cross slide (53) axis (54) is further suitably arranged by means not shown to be continuously adjustably positioned to any position (Y) from some predetermined maximum distance away from correcting link (24) rotation point (25) to a position coincident with or past correcting link (24) rotation point (25) to a suitable predetermined position.

A ratio beam (56) first end (56a) is sliding connected to a saddle bearing (57) that is in turn rotatably connected to cross slide (53) on a pivot centre coincident with that of saddle bearing (52).

Ratio beam (56) is pivotally located at some suitably selected pivot centre (58) suitably located on plane (22) at some point between ratio beam (56) first end

(56a) and second end (56b) such that symmetricai rotational flatline reciprocation of correcting link (24) about plane (22) imparts appropriate symmetrical flatline reciprocation to ratio beam (56) about plane (22) by means of sliders (52,57 and 53).

Positioning of cross slide (53) axis (54) past correcting link (24) rotation point (25) causes reverse rotation of ratio beam (56) as required.

Ratio beam second end (56b) is suitably pivotally connected to cross link (59) first end (59a). Cross-link second end (59b) is suitably pivotally connected to output clutch (60) to provide a parallelogram motion between ratio beam (56) cross link (59) and output clutch (60). The clutch (60) is caused to grip and release the output shaft (100) to impart constant rotational velocity over the flatline rotational angular sweep.

Suitable arrangement of the effective radius of the output clutch drive lug (61) about the output shaft (100) and the rotational reciprocating motion imparted to it by means of the cross link (59) and the ratio beam second end (56b) reciprocating motion about pivot (58) results in substantially pulse free or minimal pulse rotational reciprocation of the drive clutch (60) of infinitely adjustable degree through adjustment of the position of axis (54) with regard to pivot (25).

By way of example Table 1 shows the effectiveness of the system in producing continuously variable torque transmission that is substantially pulse free. As can be seen with the gear ratio (that is the ratio of input shaft rotational motion to output shaft rotational motion) of from 3.28 : 1 to 1293.9 : 1 the amount of pulsing with respect to the first degree of crank rotation is between about 0.20% and 0.27% but this is still substantially lower than the up to 30% pulsing possible with a 4 clutch arrangement, the 7,6% pulsing possible with an 8 clutch arrangement and the 3.4% pulsing possible with a 12 clutch arrangement

operated with pure non-flatlined simple harmonic reciprocating rotational input arm motion.

A second embodiment of the ratio changing device invention is shown in Figure 5. This ratio changing device utilises a reciprocating rotational input motion arm from any one of the three flatline linkage device embodiments previously described and shown in Figures 1,2 and 3. Such input motion arm is respectively referred to as correcting link (24) in Figures 1 and 2 and radial arms (114a, 114b) in Figure 3. Such motion, as previously described, exhibits flatline reciprocating rotational motion. In this embodiment the input motion arm is referred to as correcting link (24).

In this embodiment of the invention the correcting link (24) second end (24b) is sliding connected to a slider saddle bearing (52) that is in turn pivotally connected at pivot centre (202) to a radial link (200) first end (200a).

Radial link (200) is suitably rotatably connected at a second end (200b) to an adjustable pivot (201) suitably located on and adjustable along plane (22) to facilitate rotational reciprocation of pivot point (202) along curve (203) about pivot point (201). Radial link (200) is caused to rotationally reciprocate about fixed pivot (201) by the rotational reciprocating motion of the correcting link (24) second end (24b) imparting motion through slider saddle bearing (52) pivot centre (202).

Radial link (200) fixed pivot (201) is further suitably arranged by means not shown to be continuously adjustably positioned to any position (Y) from some predetermined maximum distance away from correcting link (24) rotation point (25) to a position that causes radial link (200) reciprocatable pivot point (202) to be coincident with correcting link (24) rotation point (25) or to some predetermined maximum position past correcting link (24) rotation point (25).

A ratio beam (56) first end (56a) is sliding connected to a slider saddle bearing (57) that is in turn rotatably connected to reciprocatable pivot point (202) on a pivot centre coincident with that of slider saddle bearing (52).

Ratio beam (56) is pivotally located at some suitably selected pivot centre (58) located at some point between ratio beam (56) first end (56a) and second end (56b). Ratio beam second end (56b) is suitably pivotally connected to cross link (59) first end (59a). Cross-link second end (59b) is suitably pivotally connected to output clutch (60) to provide a parallelogram motion between ratio beam (56) cross link (59) and output clutch (60). The clutch (60) is caused to grip and release the output shaft (100) to impart constant rotational velocity over the flatline rotational angular sweep.

Suitable arrangement of the effective radius of the output clutch drive lug (61) about the output shaft (100) and the rotational reciprocating motion imparted to it by means of the cross link (59) and the ratio beam second end (56b) reciprocating motion about pivot (58) results in substantially pulse free or minimal pulse rotational reciprocation of the drive clutch (60) of infinitely adjustable degree through adjustment of the position of radial link (200) fixed pivot (201) along plane (22) with regard to pivot (25).

A third embodiment of the ratio changing device invention is shown in Figure 6.

In this embodiment the flatlining device is combined with the ratio changing device to provide a special compact continuously variable transmission.

With reference to Figure 2 the flatline linkage (12) is employed in identical manner to impart flatline reciprocation rotational motion correcting link (24).

In this third embodiment as shown in Figure 6 correcting link (24) is directly connected at a second end (24b) to a cross link (96) first end (96a) by means of

a rotatable pivot (95). Cross-link second end (96b) is suitably pivotally connected to output clutch (98) by means of rotatable pivot (97).

Suitable arrangement of the effective radius of the output clutch (98) drive lug (99) and the rotational reciprocating motion imparted to it by means of the cross link (96) ensures parallel reciprocal rotation of the output clutch (98) with the correcting link (24). The clutch (98) is caused to grip and release the output shaft (100) to impart constant rotational velocity over the flatline rotational angular sweep.

Ratio change is achieved by suitable adjustment of dimensions (Y) and (X) to achieve minimum output shaft (100) pulsing at any gear ratio selected within the specified range.

For each ratio selected the rotational reciprocating motion of correcting link (24) is simultaneously corrected by suitable adjustment of the distance between input arm (20) point of rotation (21) and its connecting pivot (21 a) at end (20a), as indicated by dimension X in Figure 6, in order to maintain constant rotational velocity over the predetermined angular rotation of the input shaft (81) that relates to the constant rotational velocity or flat line output motion of correcting link (24).

As can be readily observed, as dimension Y in Figure 6 is reduced the slider (26) is consequently caused to approach the point of rotation (21) of input arm (20). As a consequence the amount of angular rotation imparted to the correcting link (24) through the slider (26) connection to the input arm (20) is reduced. However, the rotational velocity of the correcting arm (24) about its point of rotation (25) is maintained as substantially pulse free but reduced in value when compared with its previous rotational velocity value at the previous dimension setting for Y. As stated above the flat line substantially pulse free

rotational velocity characteristic is maintained by suitable simultaneous adjustment of dimension X.

As can further be readily observed, when dimension Y in Figure 6 is reduced to position the slider (26) point of rotation (24c) on the correcting link (24) coincidental with or substantially coincidental with the input arm (20) point of rotation (21) then no rotational velocity is imparted to the correcting link (24).

The effective gear ratio of such a device can be infinitely varied to any ratio required between a predetermined maximum ratio typically approximately 2,75 : 1 and a minimum ratio of infinity: 1 which provides a stationary output shaft (100) for any input shaft (81) speed of rotation.

A first embodiment of the continuously variable transmission invention combines any of the three flatlining devices together with the first ratio changing device embodiment.

A second embodiment of the continuously variable transmission invention combines any of the three flatlining devices together with the second ratio changing device embodiment.

A third embodiment of the continuously variable transmission invention employs the compact flatlining and ratio changing device embodiment described in the third ratio changing device embodiment.

A fourth embodiment of the continuously variable transmission invention is to optimise the geometric relationship of pivot centre distance (25) to (21) and slider operating plane (54) shown in Figure 4, or pivot centre distance (25) to (21) and pivot centre distance (210) to (25) in Figure 5, in order to minimise pulsing throughout a selected gear ratio range without the requirement to adjust pivot centre distance (25) to (21) for each ratio adjustment. Such optimisation

simplifies the mechanical arrangement of a continuously variable transmission according to the invention by acceptance of a slightly higher pulsing level at selected gear ratios within the selected gear ratio range in return for mechanical simplicity of the device.

A fifth embodiment of the continuously variable transmission invention is shown in Figure 13a, 13b and 13c. In this embodiment any sliding bearing arrangement is arranged with multiple slots and ribs mutually engagable with each other to provide a special compact sliding device capable of transmitting high loads in a small volume in a continuously variable transmission.

The sliding connectors (19,26) in Figure 1, (26) in Figure 2, (52,53, 57) in Figure 4, (52,57) in Figure 5 and (26) in Figure 6 play an important part in the transfer of motion and the modifying of the simple harmonic reciprocating input motion.

It has been found that it is desirable to use a specific sliding connector design (91), which is shown in Figures 13a, 13b and 13c. These figures show a slider (92) and input link (86). Slider (92) has a pivot connection point (104) for rotational connection to the modifying arm (90) end (90a). Both the slider (92) and the input arm (86) have a base (105,106) from which a series of ribs (107,108) extend, defining a series of slots (110,109) between them. The ribs (107,108) and slots (110,109) of the slider (92) and the input arm (86) are complimentarily shaped which allows the ribs (108) of the input arm (86) to be receivable within the slots (110) of the slider (92), and vice versa. This enables the creation of a large contact surface area between the slider (92) and the input arm (86) within a confined volumetric space, which enables a reduction of the contact surface pressure between them to be achieved. This results in a region within which low friction lubrication can be employed and which facilitates retention of lubricants during relative movement of the slider (92) and the input arm (86).

A sixth embodiment of the continuously variable transmission invention is shown in Figures 14a, 14b and 14c. In this embodiment any rotatable pivot bearing arrangement is arranged with multiple circular slots and circular ribs mutually engagable with each other to provide a special compact rotatable device capable of transmitting high loads in a small volume in a continuously variable transmission.

The pivotal connections (21,25) in Figure 1, (21,25) in Figure 2, (25,58) in Figure 4, (25,58) in Figure 5 and (21.25) in Figure 6 play an important part in the transfer of motion and the modifying of the simple harmonic reciprocating input motion. It has been found that it is desirable to use a specific pivotal connection design (92), which is shown in Figures 14a, 14b and 14c. These figures show by way of example a link (400) pivoted by means of a pivotal connection according to the embodiment to another link (401).

Links (400,401) both have a base (402,403) from which a series of circular ring shaped ribs (406,407) extend, defining a series of circular ring shaped slots (404,405) between them.

The circular ribs (406,407) and the circular slots (404,405) of the links (400,401) are complimentarily and circularly shaped which allows the circular ribs (406,407) to be receivable within the circular slots (404,405) and vice versa.

This enables the creation of a large contact surface area between the rotating links (400,401) to be employed within a confined volumetric space, which enables a reduction of the contact surface pressure between them to be achieved. This results in a pivot within which low friction lubrication can be employed and which facilitates retention of lubricants during relative rotational movement of the two links (400,401).

In a further aspect of this embodiment either one of rotating links (400,401) is positioned centrally over the centre of pressure of circular ribs (406,407) such that any radial load imparted by the circular ribs (406,407) to such rotating link either (400) or (401) imparts no twisting couple to that link (400) or (401) since the load is applied symmetrically at the neutral axis of the subject link (400,401) thus placing it only in pure tension or pure compression as appropriate.

A seventh embodiment of the continuously variable transmission invention is shown in Figure 15. This embodiment of the continuously variable transmission is that of a cantilever bearing arrangement for the link and arm rotation points.

By way of example, Figure 15 shows such a cantilever bearing arrangement for the arm and slider arrangement shown in Figure 15a, 15b and 15c.

The input arm (86) rotation point (87) pivot pin (111) is located within two bearings (112) and extends with one end (113) therefrom. The input arm (86) is secured to the extending end (113) of the pin (111) thereby facilitating rotation together with the pin (111) about the rotational axis of the two bearings (112).

Also shown in Figure 15 is that the modifying arm (90) rotation point (93) pivot pin (114) is similarly located within two bearings (115) and has one end (116) that extends therefrom. The modifying arm (90) is secured to the extending end (116) of the pin (114) thereby facilitating rotation together with pin (114) about the rotational axis of the two bearings (115).

This arrangement makes it possible for the modifying arm (90) and input arm (86) to cross over during their reciprocating rotational motion without mechanically interfering with each other.

An eighth embodiment of the continuously variable transmission invention is shown in Figure 16. This embodiment of the continuously variable transmission

invention employing two clutches reciprocated simultaneously is shown schematically in Figure 16.

With reference to Figures 4,5 and 6, in this embodiment shown in Figure 16 the arrangement the ratio beam (56) provides variable-reciprocating rotational output motion with a flatline velocity profile. The second end (56b) of the ratio beam (56) is rotatably connected to two clutch push links (59,59a). Each clutch push link (59,59a) is rotatably connected to an actuated or one-way clutch (60,60a) that is operatively located around an output shaft (100,100a), each arrangement the same as the arrangement shown in Figures 4,5 and 6.

Upon rotation of the ratio beam (56) about its pivot point (58) in a clockwise direction in Figure 16 both clutches (60,60a) are also rotated in a clockwise direction.

Clutch 60 is arranged to grip and rotate its associated output shaft (100) also in a clockwise direction over its predetermined degree of rotation. At the same time the second clutch (60a) is being positioned in readiness for its gripping cycle to commence.

When the ratio beam (56) finishes its clockwise constant rotational velocity rotation, the first clutch (60) is disengaged from the first output shaft (100) and commences being repositioned for its next gripping cycle.

When the ratio beam (56) has completed its clockwise rotation and commences rotation in an anti-clockwise the second clutch (60a) commences being positioned for its gripping cycle. When the ratio beam (56) commences its anticlockwise constant rotational or flatline velocity rotation the second clutch (60a) is caused to grip and rotate its associated output shaft (100a) in a anti- clockwise direction over its predetermined degree of rotation.

Therefore, with one displacement cycle of the modifying arm both the clockwise and the anticlockwise directions of rotation of the ratio beam (56) are utilized to rotate output shafts (100,100a). The rotational motion of the two output shafts (100, 100a) is geared together through a simple gearing arrangement (117) thereby enabling either output shaft (100,100a) to be employed as the final and single output shaft. By suitable sequential operation of multiples of such shaft gripping arrangements continuous pulse free or near pulse free rotation of the final single output shaft is achieved at any selected gear ratio.

The gearing arrangement (117) may also be arranged such that the two output shafts (100, 100a) are both separately geared to drive a third output shaft.

A ninth and preferred embodiment of the continuously variable transmission invention is shown in Figure 17. In this embodiment of the continuously variable transmission invention three of the two simultaneous clutch operating devices shown in Figure 16 are arranged to operate in sequential series to drive six clutches on the two output shafts (100,100a), three clutches acting to rotate a first output shaft (100) in sequence with three further clutches acting to rotate a second output shaft (100a) in complementary out of phase gripping sequence with those acting to rotate the first output shaft (100) in a continuous sequence between them, the rotation of the two shafts (100, 100a) being geared together to provide continuous pulse free or substantially pulse free rotation thereby.

With six clutches each clutch has to rotate its associated output shaft (100, 100a) by the predetermined amount corresponding to 60 degrees of rotation of an input crankshaft thereby providing continuous transmission of rotational motion for every 360 degrees of rotation of the input crankshaft at the predetermined gear ratio. This means that it is only required of the motion modification to produce flatline velocity for each output clutch (60,60a) over exactly or substantially 60 degrees of rotation of the input shaft.

In this preferred embodiment of the invention such operating arrangement as described above also provides balanced or near balanced inertial loading of the input shaft and prime mover.

This is shown graphically in Figure 17, where the inertial energy demand profile for each linkage is shown. In this diagram the term linkage is used to describe the combined flatline linkage, the ratio change device linkage and the combined two clutches linkage which together for each linkage exhibits an inertial load as it reciprocates at any given frequency.

In the example shown in Figure 18 the second linkage number 2 clutch is shown to rotate the second output shaft from 0 to 60 degrees of input shaft rotation at any selected gear ratio. Thereafter the third linkage number 2 clutch rotates the second output shaft from 60 to 120 degrees. The first linkage number 1 clutch then rotates the first output shaft from 120 to 180 degrees, and so on. When both output shafts are geared together as shown in Figure 16 to rotate at the same speed relative to each other, then the rotational impetus or inertia imparted to each one is imparted to the other simultaneously. Therefore either shaft can be arranged to be utilized as a final continuously driven flatlined output shaft without inertia pulsing load being imparted to it at any phase of its operating cycle. The output drive shaft therefore receives constant velocity rotation over each 360 degrees rotation of the input shaft and exhibits zero or near zero inertial pulsing. Further the prime mover experiences a constant inertia load at all reciprocating frequencies and at all gear ratios selected thereby minimising the requirement for utilisation of an inertia absorbing device such as a flywheel within the system.

A more detailed description of the inertial balancing described above follows for clarity. It can be seen that for each linkage inertial energy-input demand at any given time there is a matched linkage inertial energy output provided. For example, between 0 and 60 degrees rotation of the input shaft, linkage 1

decelerates thereby providing the consequential inertia energy required to slow it down to the input shaft, while linkage 2 is operating at constant rotational velocity and neither provides nor requires inertial energy and linkage 3 accelerates thereby demanding the consequential inertia energy which is provided by linkage 1. The energy input to the system is therefore balanced between linkage 1 and 3 since the acceleration and deceleration of each linkage 1 and 3 which generates the inertia energy demand and provision of each linkage 1 and 3 are exact or substantially similar opposites of each other at all times.

Since the reciprocating mass of all three linkages is the same and all pivot points are the same, the polar second moment of area for all three linkages is the same. Therefore, when each linkage is operated sequential as required by the 60 degree flatline clutch gripping phase in order to produce flatline output rotation of the output shaft, any energy imbalances that are introduced by any one linkage at any given time are consequently balanced out by an equal and opposite energy imbalance in another linkage at that same time. The same applies to all linkages for all the other intervals of 60 degrees.

A further aspect of this embodiment of the continuously variable transmission invention employs six linkages each operating one clutch arranged to operate in sequential series to drive one output shafts. Figure 17a illustrates the flatline transmission to the single output shaft and the inertia energy balance at all frequencies for the six reciprocating combined linkages A tenth embodiment of the continuously variable transmission invention employs a mechanical vibration counter balance shaft such shaft geared to rotate at a such suitable speed to match the mechanical reciprocating motion of the components comprising the continuously variable transmission invention. It is anticipated that while inertia pulsing is balanced an imbalance in mechanical vibration may be present for any given configuration of the invention. However,

since such mechanical vibration will have a frequency or frequencies which are a function of the input shaft speed, such mechanical vibrations can be cancelled and balanced out by the counter balance shaft embodiment, such shaft being fitted with suitably selected masses at suitably selected operating radiuses to achieve or significantly achieve balanced operation of the continuously variable transmission invention.

An eleventh embodiment of the continuously variable transmission invention is shown in Figures 18 and 19. In these representations it is shown how the transmission can be made more compact. By way of example consider Figure 2 in comparison with Figure 18. In Figure 18 the flatline linkage is similar in operation to that shown in Figure 2. However Reciprocating link (20) is arranged in this embodiment to be a radial link pivoted at a first end (20b) at pivot centre (21). Slider saddle bearing (26) is arranged to act upon reciprocating link (20) only between ends (20a) and (20b).

By suitable arrangement of the pivot centres (21) and (25) with respect to each other along plane (22) the motion imparted to reciprocating link (20) first end (20b) in Figure 18 is identical to that imparted to second end (20b) in Figure 2.

The consequent motion therefore imparted to correcting link (24) in both Figure 18 and Figure 2 is therefore also identical.

By utilisation of such an arrangement whereby any centrally pivoted link is instead pivoted at one end, the length of the subject link can be reduced and the consequent volume occupied by the incorporating linkage reduced while the resulting motion thereof remains unchanged.

Further, by way of example consider Figure 4 in comparison with Figure 19. In Figure 19 the ratio change device is similar in operation to that shown in Figure 4. However ratio beam (56) is arranged in this embodiment to be a radial link pivoted at a first end (56b) at pivot centre (58).

Clutch cross link (59) is rotatably connected at a first end (59a) to ratio beam (56) at some suitable point between ratio beam (56) first end (56b) and second end (56a). By suitable arrangement whereby the distance from pivot point (58) to cross link (59) rotatable connection to ratio beam (56) at first end (59a) in Figure 19 is made identical to the same referenced dimension shown in Figure 4 then the consequent motion imparted to Clutch (60) is identical in both Figure 19 and Figure 4.

By utilisation of such an arrangement whereby any centrally pivoted link is instead pivoted at one end, the length of the subject link can be reduced and the consequent volume occupied by the incorporating linkage reduced while the resulting motion thereof remains unchanged.

It will be appreciated that the invention is not limited to the embodiments described above and it is possible to alter some aspects of the embodiments without departing from the scope of the invention.