TECHNICAL FIELD

The present invention relates to devices for transforming rotary motion into oscillatory motion using three parallel shafts and five spur gears, wherein a pair of gears is fixed to the two shafts each and meshed with each other operating as "link gears" and another a pair of gears is also fixed to the said two shafts, respectively, and the remaining one is fixed to the third shaft meshing with the second pair of gears. Except link gears one or two gears, at least, must be partially toothed gears having teeth in sector. The shaft having this partially toothed gear rotates drivingly in a certain direction meshing with other gear and transmits the gear action intermittently. Through link gears these in¬ termittent actions are combined i an oscillatory motion.

BACKGROUND ART

The most wide using mechanism to transform rotary motion into osci¬ llatory motion at present is the crank and connecting link mechanism. However, this normal simple crank and link mechanism has several defects. By this mechanism, it is almost impossible to get more than 90 degrees of oscillation, even not allowing to set the shaft supporting devices on both sides and giving unequal half cycle time. But it can not be negle¬ cted that the latter fuction is contributing to us as "quick return mechanism" in many kinds of machineries.

DISCLOSURE OF INVENTION ^'

The objection of this invention is to settle the above mentioned defects and to provide a wider angular movement such as 180° including an intermittent oscillatory motion and also, in case of requiring, two opposite oscillating movement at same time. When one of the three shafts, which has a partially toothed gear only _? rotates, then the remaining a pair of shafts oscillates in opposite directions respectively. And when a pair of shafts having a pair of partially toothed gears rotates in opposite directions each other, then the gear on third shaft oscillates according to the meshing with the partially toothed gears in turn.

BRIEF DESCRIPTION OF THE DRAWING

Fig. 1 and 2 are a schematic front view and a side view showing a shaft having a partially toothed gear rotates, the other two shafts having a large gear and a smaller gear on each oscillate in opposite directions.

Fig. 3 and k_ are the same view as Fig. 1 and 2 except the cross sections of the three shafts are not lined in a row.

Fig. 5 and 6 are a schematic front view and a side view showing two shafts having a partially toothed gear and an ordinary gear on each rotate in opposite directions, the third shaft having a gear oscillates.

Fig. 7 is showing a set of plate cam.

Fig. 8 is a schematic fragmental ^' view showing the action starting point.

Fig. 9 is showing a different action starting point to Fig. 8. Fig. 10 is a schematic fragmental view showing one of the stub tooth on the driven gear.

Fig. 11 is showing one of the skewed stub tooth on the driven gear.

BEST MODE FOR CARRING OUT THE INVENTION

In Fig. 1 and 2 a-j is a rotating input shaft and b-j , bn are the oscillating sha ts paralleled to a- _j . A is a partially toothed gear having teeth in sector and is fixed to shaft a.. , and a pair of gears B- _j and 2 is fixed to shaft b-| and D2, respectively, meshing with the gear A in turn when it rotates to R direction. Another pair of big gears C'j and C2 meshing with each other is fixed to the shaft b- _j and b2 , too. Now designate Z _A the total number of teeth (or the number of ^* circular pitches) could be made on the gear A and Zg that of the gear B-j or B2. is the number of remained teeth on gear A and β is the αegrees of the center angle both indicating the number of teeth (or the number of circular pitches) in the intercepting range between to the addendum circles of the gear A and B.

In Fig. 2 d = 5 and gear A rotating to the R direction turns the gear B- _j to the Lo direction. When the sector of teeth 1, 2, 3, ^ , 5 comes to the place 1', 2', 3', *+', 5 then the position of the all gear teeth of B- _j and B ₂ becomes 1', 2", 3', +', 5' , , turning the shaft b- _j to Lo and b2 to Ro direction with the angle Q and then the shafts b-j and b2 with their gears will stop for an in¬ stant. The next moment the teeth 1', 2', 3', +', 5' of the gear A mesh with the teeth 1', 2 ¹ , 3 ¹ , ^', 5' of the gear B ₂ turning shafts b-j and b2 in the opposite directions each other with the angle Q . That is, the rotation of R direction of the shaft a- _j turns

the shafts b-j and b2 to the opposite directions with the angle β .

Here designate ύ c the maximum number of c _. on gear A, then in the equation _____ _ Λ + - _| .> <^ _x . _ β + 1 _» we can obtain

Cλ.x which should be a whole number satisfacting in the above equation and d. is in the range c(x ^_ d *> 1.

And in Fig.2. _{r =} ^A _ ( ^ ₊ ^ _ . ^ hence Q is Q= d. +

(whereas r« = r - 0.5X and X is cardinal numbers such as 1, 2, 3, ..,etc. This means r* is always less than 0.5)

In the equation the oscillating angle _ β is also indicated by in the number of teeth or the number of circular pitches.

As shown in Fig. 2, just after coming out the 5th tooth of the gear A from 5th and 6th tooth of the gear B ₂ , 1st tooth of gear A starts to mesh with the 1st tooth of the gear B^ Here, if r is ^■ _τ _\l> T-^ ^{> Q} > ^tiιen that the gear system has itself the locking cam ability to prevent free rotation of the shafts b- _j and b , but if ^T ^> , then the gear system has not the locking cam ability by itself. In this case a special device should be arranged to this system to prevent the free rotation of the shafts b- _j and b .

In Fig. 7 the plate cam having a locking arc P _a on plate C _a on "the driving shaft a- _j and saddle curves P^ on plate C^ on the driven shafts b- _j and bg will -ct as a kind of Geneva - Stop mechanism. To make this simple, attache a locking arc to the recess side of the tooth flank on θ(th tooth of the driving gear and a saddle curve to the space where a few tooth were pulled out from just after the θ6bh tooth of the driven

gear. Through these kinds of method, a smooth oscillatory movement can be achieved, whether T is less than X or not.

In a case, as shown in Fig. 3 and ., the cross sections of the three shafts form a triangle, the angle ^b- _j a^ b2 indicate as. (j) , and then C(x is obtained from the following equation

but Q is still calculated by the equation,

Q = cL + (3 + r ^« - 11 _β

As shown in Fig. while the teeth 1, 2, 3, ^ on the driving partially toothed gear come to the place 1', 2', 3', *', rotating to L direction, - _j sha t rotates to Ro direction and while the A gear teeth comes to the place 1", 2", 3", ⁱ +", 2 shaft rotates to Ro direction, and then the both shafts will stop with a relatively long stopping time. In the above case, after the half cycle of the oscillatory motion, the stopping time is not equal to that of the one cycle. So this motion is one cycle intermitt¬ ent motion."

Now, in the example shown by the Fig. 5 and 6, the two parallel shafts a-j and a2 having a pair of meshing gear C- _j and C2 , as link gear, on each shaft and rotate in the opposite directions. On the said shafts a-j and a2 a pair of partially toothed gear A- _j and A , which size is equal or smaller to that of the link gears, is fixed. The arrangement of gear A2 is, after rotating A- _j gear to 180° around the shaft a- _j symmetrizing to the line vertical to a- _j - a ₂ line and passing through to the center of the shaft b-j . The oscillating gear B is fixed to this shaft b-j which is parallel to the rotating shafts a-j and a2, meshing with the two gears A- _j and A2 in turn.

In this example the cross sections of the three shafts form a triangle. First the teeth on gear A- _j meshes with the teeth on gear B, turning it to Lo direction and then the teeth on A2 meshes with the teeth on gear B, turning it to Ro direction.

Here again C-( _x is the maximum number of the remained tooth on the rotary input gears A-j and A2 _f and can be obtained from the same equation, as said,

and the oscillating angle # = C. ₊ θ ₊ r' - l l

2 ^•

All the examples in the above, the action starting point would be either S- _j in Fig. 8 and S2 in Fig. 9 or a point between these two points.

If the action starting point comes on a point between S- _j . and S2, this is called to be stable, but if the action starting point comes on the point S-j, it is unstable case, a special treat is required, doing the 2nd tooth of the oscillatory output gear to be a stub tooth as in Fig. 10 and 11. S2 point is also a very unstable point and should be avoided.

In any case, it can be adjusted by varying the size and form of the cams, acting as a kind of Geneva Stop mechanism _; and the clearance of the center distance of the shafts to get a smooth operation.

INDUSTRIAL APPLICABILITY

This invention is good to apply for the relatively low speed and light load because of the impact which arises at the action starting moment. It is also desired to reduce the stand still moment of inertia by using springs, cams and etc. To avoid the weakness of the first tooth

on the gears, it is also suggested to rotate the input gear, which has the Geneva Stop cam, in the reverse direction.

By this invention, we can get a oscillatory motion in almost uniform angular velocity with high efficiency, and the oscillating angle (7 can be obtained from β ~ — *° ^{even more} ^ ^X8X1 - 360°. And by adjusting the number and position of & on the gear, various oscillatory motions can be obtained from the relatively simple embodiment.

As first attempt, this invention can easily be tried to apply to the wide range wiper brushes on automobiles, to the traditional wind fans oscillated by electric power, to the toys required various oscillatory motions and etc.