WO1986002706A1

WO1986002706A1 - Device for transforming rotary motion into oscillatory motion

Info

Publication number: WO1986002706A1
Application number: PCT/KR1985/000020
Authority: WO
Inventors: Soon Yoon Han
Original assignee: Kim, Soon, Ki
Priority date: 1984-10-24
Filing date: 1985-10-24
Publication date: 1986-05-09
Also published as: KR870000018B1; KR860003454A; AU5065085A; EP0243351A1

Abstract

A device to get oscillatory motion with high efficiency and wide oscillating angle in relatively low speed and light load using three shafts and five spur gears, wherein a pair of ordinary gears fixed to two shafts meshes with each other as link gears and another pair of gears fixed to the same shafts, respectively, meshes with the remaining one on third shaft on both sides. Except link gears, one or two gears, at least, must be partially toothed gears having teeth in sector. When a shaft having only a partially toothed gear rotates, the remaining pair of shafts oscillates. And when a pair of shafts having a pair of partially toothed gears rotates in opposite directions, the third shaft having only a gear oscillates. To make this motion securely and smoothly a set of cam acting as Geneva Stop mechanism is required.

Description

DEVICE FOR TRANSFORMING ROTARY MOTION INTO OSCILLATORY MOTION

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 intermittent actions are combined in an oscillatory motion.

BACKGROUND ART

The most wide using mechanism to transform rotary motion into oscillatory 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 neglected 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 4 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 a₁ is a rotating input shaft and b₁ , b₂ are the oscillating shafts paralleled to a₁. A is a partially toothed gear having teeth in sector and is fixed to shaft a₁, and a pair of gears B₁ and B₂ is fixed to shaft b₁ and D₂, respectively, meshing with the gear A in turn when it rotates to R direction. Another pair of big gears C₁ and C₂ meshing with each other is fixed to the shaft b₁ 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 Z_B that of the gear B₁ or B₂. α 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 B₁ to the Lo direction. When the sector of teeth 1, 2, 3, 4, 5 comes to the place 1', 2', 3', 4', 5 , then the position of the all gear teeth of B₁ and B₂ becomes 1', 2", 3', 4', 5 ', , turning the shaft b₁ to Lo and b₂ to Ro direction with the angle Q and then the shafts b₁ and b₂ with their gears will stop for an instant. The next moment the teeth 1', 2', 3', 4', 5' of the gear A mesh with the teeth 1', 2', 3', 4', 5 ' of the gear B₂ turning shafts b₁ and b₂ in the opposite directions each other with the angle θ . That is, the rotation of R direction of the shaft a₁ turns the shafts b₁ and b₂ to the opposite directions with the angle θ.

Here designate αx the maximum number of α on gear A, then in the equation _____ _ β + 1 ≥ αx ≥ M - β + 1 _» we can obtain

αx which should be a whole number satisfacting in the above equation and d. is in the range

αx ≥ d ≥ 1.

And in Fig.2. _{r =} - ( α+ β - 1 ) hence θ is θ = d + β 1

(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 θ 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 B₂, 1st tooth of gear A starts to mesh with the 1st tooth of the gear B₁ Here, if r is ½ > y > 0 , ^tiιen

that the gear system has itself the locking cam ability to prevent free rotation of the shafts b₁ and b₂, but if r ≥ ½ , 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 b₁ and b₂.

In Fig. 7 the plate cam having a locking arc P_a on plate C_a on "the driving shaft a₁ and saddle curves P_b on plate C_b on the driven shafts b₁ and b₂ will ect as a kind of Geneva - Stop mechanism. To make this simple, attache a locking arc to the recess side of the tooth flank on αth tooth of the driving gear and a saddle curve to the space where a few tooth were pulled out from just after the αth 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 4, the cross sections of the three shafts form a triangle, the angle <b₁ a₁ b₂ indicate as. ω, and then αx is obtained from the following equation

ω ≥ αx + β - 1

but θ is still calculated by the equation,

θ = α + β + r' - 1

As shown in Fig. 4 while the teeth 1, 2, 3, 4 on the driving partially toothed gear come to the place 1', 2', 3', 4', rotating to L direction, b₁ shaft rotates to Ro direction and while the A gear teeth comes to the place 1", 2", 3", 4", b₂ 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 intermittent motion."

Now, in the example shown by the Fig. 5 and 6, the two parallel shafts a₁ and a₂ having a pair of meshing gear C₁ and C₂ , as link gear, on each shaft and rotate in the opposite directions. On the said shafts a₁ and a₂ a pair of partially toothed gear A₁ and A₂, which size is equal or smaller to that of the link gears, is fixed. The arrangement of gear A₂ is, after rotating A₁ gear to 180° around the shaft a₁ symmetrizing to the line vertical to a₁ - a₂ line and passing through to the center of the shaft b₁. The oscillating gear B is fixed to this shaft b₁ which is parallel to the rotating shafts a₁ and a₂, meshing with the two gears A₁ and A₂ in turn. In this example the cross sections of the three shafts form a triangle. First the teeth on gear A₁ 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 αx is the maximum number of the remained tooth on the rotary input gears A₁ and A₂ , and can be obtained from the same equation, as said,

and the oscillating angle θ = α + β + r' - 1

All the examples in the above, the action starting point would be either S₁ 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 S₁ and S₂, this is called to be stable, but if the action starting point comes on the point S₁, 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 θ can be obtained from β - to even more than 360°. And by adjusting the

number and position of α 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.

Claims

CLAIM

1. A partially toothed gear device for transforming rotary motion into oscillatory motion, comprising five spur gears are fixed to the three parallel shafts, wherein a pair of ordinary gears is fixed to the two shafts, respectively, meshing with each other, and the remained three gears are fixed to the three, shafts, respectively, in such a way that whether a rotating input gear having teeth in sector, which is fixed to a shaft alone, meshes with the two gears in turn, or a oscillating output gear, which is fixed to a shaft alone, meshes with a pair of gears having teeth in sector, in turn, and by one or two of the rotating shafts having partially toothed gear the oscillating output motion is achieved in one or two shafts.

2. A device as claimed in claim 1 comprising the cams acting as Geneva Stop mechanism, wherein a locking arp cam is attached to the recess side of the tooth flank on the last tooth of the rotary driving gear, and a saddle curve cam is attached to the space where a few tooth were pulled out from just after the determined number of tooth of the driven gear, so as this saddle curve cam corresponds with the locking arc cam to get a smooth motion.