US3529485A

US3529485A - Step-by-step feed gear

Info

Publication number: US3529485A
Application number: US761195A
Authority: US
Inventors: Rainer Kofferlein
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1967-09-29
Filing date: 1968-09-20
Publication date: 1970-09-22
Anticipated expiration: 1987-09-22
Also published as: FR1583017A

Description

STEP-BY-STEP FEED GEAR Filed Sept. 20, 1968 Fig. 1

BY ATTYS.

United States Patent I 3,529,485 STEP-BY-STEP FEED GEAR Rainer Kiitferlein, Munich-Solln, Germany, assignor to Siemens Aktiengesellschaft, Erlangen, Germany, a corporation of Germany Filed Sept. 20, 1968, Ser. No. 761,195 Claims priority, application Germany, Sept. 29, 1967,

83 Int. Cl. F16h 27/64, 35/02, 37/12 U.S. Cl. 74394 6 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Field of the invention This invention relates in general to step-by-step feed mechanisms such as, for example, for feeding cards or tapes through recording devices. Modern data feeding and discharging equipment requires high-speed processing apparatus. Particularly in printing and punching units with step-by-step feed the increasing speed has caused difficulties because of the alternate acceleration and deceleration operations. This has required that the masses of th accelerated and decelerated parts he made as small as possible.

Description of the prior art Step-by-step feed gears have been known in which a planetary wheel is put into oscillatory movement around a principal gear axis. An oscillating movement is superimposed over the uniformly developing hob gear movement in the planetary gear so that the speeds of both movements add up at certain times to zero at the output. The oscillating movement of the planetary wheel is generated by a curve drive whose curve may be designed as desired within wide limits.

Although in such gears the masses which are moved at non-uniform rates are relatively small in relation to the step-by-step feed gears, there is still a considerable oscillating mass due to the arm that oscillates the planetary wheel.

Further efforts were made to obtain oscillating movement to be superimposed over the uniform movement from gear parts moved as uniformly as possible. This led to an additionally proposed step-by-step feed gear, characterized by a gear with a rotating part, whereby an oscillating movement is caused on the output which is large enough to compensate at certain times for the otherwise uniform movement. An additional gear generates on the output side an additional movement of comparatively low amplitude which is used to counteract to a substantial extent for the deviations of the object to be moved from a resting position.

Although rather good results were obtained with such step-by-step feed gears, they are very expensive.

3,529,485 Patented Sept. 22, 1970 SUMMARY OF THE INVENTION The present invention relates to an intermittent drive of the step-by-step feed gear type which has very few parts and in which the output rotates in a multiplicity of steps as desired and which is usable for high step frequencies as, for example, between to 200 steps per second. A rocker arm is mounted on the output shaft and follows a curved disk which rotates around a support shaft mounted eccentrically in a rotating disk. A sprocket gear is mounted on the shaft which supports the curved disk and engages a fixed sprocket wheel which engages the other sprocket wheel thereby causing the curved disk to rotate. A drive shaft is coupled to the rotating disk to drive it. The structure results in a step-by-step feed gear which has very few parts and in which only the driven shaft with the rocker arm must be accelerated and decelerated. The remaining parts of the structure rotate at uniform speeds and thus may be designed with a substantial mass since they do not have to be continuously accelerated and decelerated.

The step-by-step gear, according to the invention, can be designed almost free from play and is appropriate for high step frequencies.

Other objects, features and advantages of the present invention will be readily apparent from the following detailed description of certain preferred embodiments thereof taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the step-by-step gear arrangement according to this invention; and

FIG. 2 is a graph illustrating the sequence of movements in the step-by-step gear arrangement.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a supporting plate 5 to which is nonrotatably attached a sun gear 6. The planet gear 3 engages the sun gear 6 and is supported on a shaft 2 which extends through a disk gear 1. The shaft 2 is rotatably supported in the disk gear 1 by the bushing 9 and carries a cam 4 on the opposite side of the disk gear 1. The drive shaft 10 carries a drive gear 12 which meshes with the teeth of the disk gear 1 to drive it. A driven shaft 8 carries a rocker arm member 7 which has a cam follower 13 that engages the surface of the cam 4. A pin 14 is mounted on the disk gear 1 and a spring 11 extends between the pin 14 and the lever arm 7 to bias the lever arm toward the cam surface 4.

The driving shaft 10 rotates the gear 12 which in turn causes the disk gear 1 to rotate. As the disk gear rotates relative to the plate 5, the sun gear 6, which is nonrotatably connected to the plate 5, drives the planet gear 3 thus rotating the shaft 2. The shaft 2 drives the cam 4 and the cam 4 causes the cam follower 13 of the rocker arm 7 to move, thus driving the output shaft 8.

The shaft 10 and disk gear 1 and shaft 2 and planet gear 3 and cam 4 may be rotated at a constant angular velocity and only the crank arm 7 and the output shaft 8 will be driven in step fashion.

Thus, the parts of the step-by-step feed mechanism may be made relatively heavy except for the rocker arm 7. This is because the remaining parts of the apparatus rotate with a fixed velocity. It is to be understood that the axis of rotation of the driven shaft 8 coincides with the axis of rotation of the disk gear 1. The disk gear 1 is mounted concentrically with the sun gear 6.

FIG. 2 illustrates the step motion obtainable with the mechanism of FIG. 1. The curve A illustrates the motion of the disk gear 1 as a function of time as it rotates at a fixed velocity. The oscillating movement caused by the cam 4 is illustrated by curve B in FIG. 2. The movements of curves A and B are added and result when the cam 4 has an appropriate shape to the desired step movement of the driven shaft 8. This is illustrated by the curve A plus B in FIG. 2 which shows the movement of the driven shaft 8 as a function of time. The only lost motion which would occur in the structure would be between the cam shaft 2 and the disk gear 1 and the planet gear 3 and the sun gear 6. This can be substantially reduced by the eccentric bushing 9 in which the shaft 2 is mounted.

The structure of FIG. 1 requires only that the driven shaft 8 and rocker arm 7 be accelerated and decelerated and the remaining moving part of the structure rotate at uniform speed. They may therefore be designed relatively heavy and may act as a gyrating mass.

Although the cam surface 4 and the cam follower 14 are shown as spring loaded, it is to be realized that the cam 4 could be formed with a groove in which the cam follower rode to obtain intermittent step-by-step motion of the shaft 8.

A further embodiment of the step-by-step gear mechanism may be obtained by rotating the sun gear 6 relative to the plate 5 to add its motion. This would result in a variation of the magnitude of the step-by-step feed in a simple manner.

Although various minor modifications might be suggested by those versed in the art, it should be understood that I wish to embody all such modifications as reasonably and properly come within the scope of my contribution to the art.

I claim as my invention:

1. A step-by-step feed gear mechanism for a driven shaft comprising,

two parts coupled to each other, one of which would by itself cause a uniform feed motion and the second part coupled to the first part to add an oscillating movement so that the driven shaft is accelerated and decelerated comprising,

a rocker arm mounted on the driven shaft.

a rotating disk gear,

a cam engageable with said rocker arm and said cam mounted on a cam shaft for rotary motion,

the cam shaft eccentrically mounted in said disk gear,

a planet gear mounted on the cam shaft, and

a sun gear concentrically mounted relative to the disk gear and engaged by the planet gear and causing rotation of the cam, and

said cam also rotating with its shaft on a circular orbit around the axis of the driven shaft.

2. A step-by-step feed gear mechanism according to claim 1, whereby the rocker arm engages the cam in the area of the circular orbit described by the axis of the cam.

3. A step-by-step feed gear mechanism according to claim 2 whereby the rocker arm is spring biased in engagement with the cam.

4. A step-by-step gear mechanism according to claim 1 whereby the sun gear is stationary.

5. A step-by-step gear mechanism according to claim 1 comprising a driving shaft and whereby the disk gear is driven by the driving shaft.

6. A step-by-step gear mechanism according to claim 5 wherein a driving gear is mounted on the driving shaft and the disk gear is formed with gear teeth which mesh with the driving gear.

References Cited UNITED STATES PATENTS 2,845,808 8/1958 Stover 74-394 2,861,672 11/1958 Buehrer et a1. 3,076,351 2/1963 Moss 74-394 OTHER REFERENCES Mathurin, E. L. and Wooding, E.R.: Epicyclic Incremental Motion Mechanism.

In IBM Technical Disclosure Bulletin 4(2), p. 4, July 1961.

LEONARD H. GERIN, Primary Examiner U.S. Cl. X.R. 74-52, 84