This invention relates to a coupling for a drive means and more specifically to a drive means incorporating a coupling that allows for the drive means to be conveniently engaged and disengaged from a driven member.

The coupling between a drive and its driven member is exposed to considerable pressures and stresses and as a result frequently requires servicing and/or replacement. Indeed, couplings serve as a link between a drive means and a driven member and are frequently formed of materials such as metal and the like which are responsible for the transfer of considerable stresses, including torsional and vibrational stresses, produced between the coupling and the driven member along the drive train thus resulting in the stressing and wear of the coupling and other parts which can be costly and time consuming to repair or replace.

Further, when a drive is semi-permanently coupled to its corresponding driven member, disengaging the coupling (and as such the engine) from its driven member can be a complex and time consuming task requiring the apparatus to be broken down in order to gain access to the coupling to effect the disengagement.

Another problem with coupling arrangements is running contact which results in the wearing of components due to friction. Running contact of components when the drive and driven member are engaged is clearly undesirable and can greatly affect the working life of the coupling. Present methods for dealing with the problem of running contact are less than adequate.

The present invention seeks to provide a coupling means which at least assists in overcoming the difficulties discussed above. The coupling means of the present invention is suitable for use in a variety of applications and is especially

applicable in situations where a drive means is required to be disengaged and re-engaged intermittently.

The present invention provides a coupling means for engaging and disengaging a drive means from a driven member, the coupling means comprising a drive means associated portion and a driven member associated portion, at least one of the said associated portions being stress absorbent, and at least one of the said associated portions being moveabie relative to the other said associated portion between a first position at which the drive means is disengaged from the driven member and a second position at which the drive means engages the driven member.

The drive means associated portion may be of various forms. In one preferred form, the drive means associated portion is provided by a stress absorbent coupling member. Preferably, the stress absorbent coupling member is slidably mounted on a shaft forming part of the drive means, such that the coupling member may slide along the shaft to engage and disengage the drive means from the driven member. Alternatively, the stress absorbent coupling member may be fixed on the shaft and the shaft is adapted to be moveabie to allow the stress absorbent coupling member to slide in and out of engagement. In yet another alternative, the stress absorbent coupling member may be moved in and out of engagement by moving the entire drive means relative to the driven member.

Preferably, the engagement and disengagement of the drive means from the driven member is achieved by movement of the stress absorbent coupling member relative to either or both of the drive means and driven member. In this respect, the stress absorbent coupling member may be of various forms. In one preferred form, the stress absorbent coupling member is provided by a portion of the driven member. Alternatively, the coupling member may be provided as a portion of the drive means.

It will be appreciated that the stress absorbing capability of the coupling member prevents the transfer of stresses including torsional and vibrational stress to other parts of the drive means and driven member. The stress absorbent coupling member may thus be formed partly or wholly of a variety of materials having stress absorbing qualities. In one particular form, the stress absorbent coupling member is formed at least partially of a rubber material.

Further, the coupling means of the present invention allows for the mechanical isolation of the engageable components. Thus, when the drive means is disengaged from the driven member there is no contact and no wearing of the components.

The driven member associated portion may be of various forms. In one preferred form, the driven member associated portion is provided by a stress absorbent coupling member. Alternatively, the driven member associated portion may be adapted to receive the drive means associated portion in the form of a stress absorbent coupling member.

In the most preferred form of the present invention, the drive means associated portion is a stress absorbent coupling member and the driven member associated portion is adapted to engagedly and releasably receive the stress absorbent coupling member. Indeed, the following description of the additional preferred features of the present invention will (for ease of reference) refer to this most preferred form. However, it must be appreciated that the following description is not to limit the generality of the above description.

With this in mind the present invention also provides a coupling means comprising a stress absorbent coupling member, a shaft operably connected to a drive means, and an actuating member, the stress absorbent coupling member being slidably mounted on the shaft such that on operation of the actuating member, the stress absorbent coupling member is caused to slide along the shaft between a first position at which the drive means is disengaged from the

driven member and a second position at which the drive means engages the driven member.

The shaft may be of various configurations provided it can accommodate the stress absorbent coupling member. In one preferred form, the shaft is splined and the coupling means is mounted on the splined shaft such that on rotation of the shaft the stress absorbent coupling member is also caused to rotate.

The shaft may also incorporate a locating means preferably in the form of interengageable portions of the shaft and the coupling member. In this preferred form, the interengageable portion of the shaft is preferably in the form of first and second grooves located around the circumference of the outer surface of the shaft. Further, the interengageable portion of the stress absorbent coupling member is provided by a detent, preferably in the form of a spring and ball bearing arrangement. The locating means allow for the stress absorbent coupling member to be releasably and positively engaged at a first position at which the drive means is disengaged from the driven member and a second position at which the drive means engages the driven member.

The coupling means of the present invention may be provided as a retro-fit in which the coupling member is mounted on the shaft of an existing drive means via a sleeve member. Alternatively, the coupling member may be mounted directly on a suitable shaft. In this respect, if the coupling member is to be mounted directly on the shaft of a drive means it may be necessary to replace the original shaft with a shaft that is compatible with the coupling member.

The actuating member is preferably provided by a handle means or the like which may be levered to allow for a small movement of the handle means to cause a relatively large movement of the stress absorbent coupling member. Thus, the actuating member is preferably a levered handle means operably connected to the stress absorbent coupling member such that on movement of the handle the stress absorbent coupling member is caused to slide along the

shaft. Of course the actuating member may be mechanical, pneumatic or hydraulic.

Furthermore, the handle means is preferably operably connected to the coupling member via an intermediate member, preferably a yoke, the intermediate member preferably forming a backing to the stress absorbent coupling member. Thus, it will be seen that the actuating member allows for convenient manual engagement and disengagement of the drive means by causing the stress absorbent coupling member to slide along the shaft to engage and disengage the driven member.

The intermediate member may be of various forms and preferably is formed as circular member having a recess at its radial surface. The recess preferably being adapted to receive a contact member such as a pin or the like, the contact between the pin and the recess of the circular member serving to effect the movement of the coupling member on operation of the actuating means.

The operation of the handle causes the contact member to contact the recess of the circular and cause the coupling member to move along the shaft between its first and second positions. Once the coupling member has been located in its first or second position the contact member may be moved to a position in the centre of the recess at which there is no contact with the edges of the recess and the circular member may rotate without friction with the contact member.

Thus, the present invention also provides a coupling means comprising a stress absorbent coupling member, a shaft operably connected to a drive means, and an actuating member, the stress absorbent coupling member being slidably mounted on the shaft such that when the coupling member is in the second position there is no running contact between components of the coupling means.

The present invention thus provides a coupling means that allows for a drive means to be conveniently disengaged and engaged from a driven member. It

will be appreciated that when disengaged there is no frictional contact between the drive means associated portion and the driven member associated portion. Thus, the present invention provides a coupling means delivering a torsionally elastic drive and allows for mechanical isolation of the engageable components.

This invention will now be described in relation to two preferred embodiments thereof as illustrated in the accompanying drawings. However, it will be understood that the generality of the above description is by no means limited by the description of the embodiments.

Figure 1 is a perspective view of a coupling means according to a first preferred embodiment of the present invention including a drive means together with a compatible driven member which forms a portion of a compressor or some other like apparatus; and

Figure 2 is a side view in cross section of the coupling means of Figure 1 shown with the drive means fitted to the driven member and in the disengaged position;

Figure 3 is the coupling means of Figure 2 shown with the drive means in the engaged position.

Figure 4 is a perspective view of a coupling means according to a second preferred embodiment, with an alternative actuating member arrangement.

Figure 5 is a side view in cross section of the coupling means of Figure 4 with the drive means disengaged from its compatible driven member.

Figure 6 is a side view in cross section of the coupling means of Figure 4 with the drive means engaged with its compatible driven member.

The coupling means of the preferred embodiments are designed for use with a driven member in the form of a compressor or some other similar apparatus. The preferred embodiment of Figure 1 shows a portion of an drive means generally indicated by the numeral 12 as a portion of the drive means, and a portion of the compressor 10. In this respect, it is envisaged that one application of the coupling means of the preferred embodiments will be in relation to compressors used in the mining industry. Compressors of this type are used in drilling procedures and at intermittent times during the drilling procedure air from the compressor is required. The coupling means of the preferred embodiments allow the compressor to be operated intermittently during the drilling procedure.

The portion of the driven member 10 incorporates a shroud 14 which is bolted to a compatible portion 16 of the portion of the drive means 12 so as to fully enclose all the moving parts to protect both persons external to the apparatus and also to protect the internal components of the apparatus from damage from external factors. The shroud 14 incorporates an inspection port 18 to enable the internal functioning of the apparatus to be assessed by an external user as well as to assist in positioning the stress absorbent coupling member 20 for engagement with the compatible portion 26 which is mounted onto the engine 12 in this embodiment.

The stress absorbent coupling member 20 is formed of a stress absorbing rubber and is slidably mounted on a shaft 22 via a splined sleeve 23, the stress absorbing coupling member 20 is of a generally circular cross section and has a convoluted radial surface 24 formed so as to be compatible and interlockingly engagable with the compatible portion 26 of the engine 12.

An actuating member in the form of a levered handle 28 is used to operate the coupling means 12. Operating the handle 28 acts to manually engage and disengage the stress absorbing coupling member 20 and thus the drive means 10 from the engine 12. The handle 28 is operably connected to an operator arm

42 incoφorating a contact member in the form of a bolt 50. The arm 42 is pivotally supported from an intermediate member in the form of a yolk 30 which is attached to the back of the coupling member 20. On movement of the handle 28 the shaft of the bolt 50 which is positioned within the recess of the yolk contacts the yoke 30 and thus causes movement of the coupling member 20 along the splined sleeve 22 between a first position at which it is disengaged from the compatible portion 26 of the engine 12 and a second position at which the coupling member 20 is engaged to the compatible portion 26 of the engine 12.

A locating means comprising a spring 32 and ball bearing 34 arrangement is provided to releasably locate the coupling member 20 at its respective engaged and disengaged positions. The ball bearing 34 locates in one of two locating grooves (not shown) on the splined shaft 22 and serves to releasably locate the coupling member 20 in its disengaged and engaged positions. The clicking of the ball bearing 34 into the locating groove also serves as an indicator to the operator as to the position of the coupling member 20.

The handle 28 is provided with a shroud 45 which incorporates a positioning means to assist in positively locating the handle 28 when the coupling member is in its engaged and disengaged positions and ensures that there is no running contact between components when the coupling member 20 is engaged. The shroud 45 includes a pair of stops in the form of pins 46, 48 together with a holding means in the form of a pair of bores 36,38 to locate and hold the handle 28 in a position at which there is no contact between the yoke 30 and the shaft of bolt 50. The handle 28 also has a bore such that when the handle is in position for the coupling member to be engaged or disengaged, a pin or bolt 39 may be passed through the handle 28 and one of the locating bores 36, 38 to releasably hold the handle 28 in place.

To engage the coupling member 20, the handle 28 is moved to its extreme position adjacent stop 46 and the coupling member 20 locates in the locating

groove (not shown). Once the coupling member is so located the handle 28 is moved so bore 39 in the handle aligns with the bore 36 in the shroud 45 the coupling is engaged. Once secured in this position there in no running contact between the yoke 30 and the shaft of bolt 50 as the shaft is centrally located within the recess of the yoke 30.

Thus, the operator can conveniently engage and disengage the drive means 12 from the compressor 10 as required. By moving the handle 28 about its pivot point 40 the operator arm 42 is caused to act on the yolk 30 via the shaft of bolt 50 which results in the coupling member 20 sliding along the shaft 22 between the two locating grooves (not shown).

The coupling means 112 of the second embodiment shown in figures 4-6 is similar to the first embodiment but includes an alternative actuating means in the form of a side mounted handle 128 and employs a coupling member 120 mounted directly on the shaft 122 rather than employing a sleeve member. In addition it incorporates an inspection hatch 119 which may be opened or closed as desired to view the internal workings of the coupling means. In most other respects the coupling means of the second embodiment corresponds with that of the first embodiment.

The actuating means comprises a handle 128 connected to a crank shaft 129 which extends across the back of the coupling member 120. The crank shaft 129 supports two operator arms 142 which incorporate bolts 150 located at diametrically opposed points at the rear of the coupling member 120, the shaft of the bolts 150 extending into the recess of yoke 130. Thus, on operation of the handle 128, the crank shaft 129 is caused to rotate and the operator arms 142 effect movement of the coupling member 120 along the shaft 122 via contact between the shaft of bolts 150 and the sides of the recess in the radial surface of the yolk 130.

The handle 128 also incorporates a shroud 145 including locating pins 146, (not shown) and locating bores 138, (not shown) to releasably locate the handle 128 in position. As in the first embodiment the handle 128 has a bore to allow for a pin or bolt 141 or the like to pass through the handle 128 and one of the bores 138, (not shown) to releasably hold the handle 128 in position. A chain 147 is attached to the bolt 141 and mounted on the shroud 145 to ensure the bolt 141 is not misplaced when disengaged from the apparatus to effect movement of the handle 128.

The coupling means of the second embodiment operates in a similar fashion to that of the first embodiment. To engage the coupling member 120 the handle 128 is moved to its extreme to abut pin 148. At this position the coupling means 120 is located in the groove 148 via the spring 132 and ball bearing 134. The handle 128 is then moved so that the bore (not shown)in the handle 128 aligns with the bore 138 in the shroud 145 and the handle 128 is secured with pin 141 such that whilst the coupling means is engaged there is no running friction between the yoke 130 and the shaft of bolt 150 which is centrally located within the recess in the radial surface of yoke 130.

It will be realised that there will be modifications in addition to those discussed above. Such modifications being apparent to one skilled in the art. These modifications are to be included within the scope of the present invention.