US2517251A - Operating mechanism for printing presses and the like - Google Patents

Description

Aug. 1, 1950 J. SINKQVITZ OPERATING MECHANISM FOR PRINTING PRESSES AND THE LIKE 6 Sheets-Sheet 1 Filed Feb. 1, 1946 IN V ENTO R dosepfzf/hA ow'fz z LM w m mkmmwm kkk Aug. 1, 1950 J. SINKOVITZ OPERATING MECHANISM FOR PRINTING PRESSES AND THE LIKE 6 Sheets-Sheet 2 Filed Feb. 1, 1946 W m m M N Aug. 1, 1950 J. SINKOVITZ OPERATING MECHANISM FOR PRINTING PRESSES AND THE LIKE 6 Sheets-Sheet 5 Filed Feb. 1, 1946 g- 1950 J. .SlNKOVlTZ 2,

OPERATING MECHANISM FOR PRINTING PRESSES AND THE LIKE Filed Feb. 1, 1946 6 Sheets-Sheet 4 INVENTOR 1, 1950 v J. SINKOVITZ 7,

OPERATING MECHANISM FOR PRINTING PRESSES AND THE LIKE Filed Feb. 1, 1946 6 Sheets-Sheet 5 ;\I 64 W I I r n a n fi n n r n r l N v E N TO R dose 0h Jmkowfz Aug. 1, 1950 J. SINKOVITZ 17,

OPERATING MECHANISM FOR PRINTING PRESSES AND THE LIKE Filed Feb. 1, 1946 6 Sheets-Sheet 6 INVENTOR 2% I 27 74 Joseph f/nA ou/fz fatented Aug. 1 195 OPERATING MECHANISM FOR PRINTING PRESSES AND THE LIKE Joseph Sinkovitz, Pittsburgh, Pa., assignor to Miller Printing Machinery 00., Pittsburgh, Pa., a corporation of Pennsylvania I Application February 1, 1946, Serial No. 644,918

8 Claims. f 1

This invention relates to operating mechanism for printing presses and the like. It relates particularly to operating mechanism for a printing press or the like having anoscillating element such as a bed. The invention provides means for driving the oscillating element; when it is employed for driving the bed of a printing press I each end of the strokegalso the bed driving mechanism has had a tendency to skew the bed. Both of these factors are greatly, magnified in,

presses operated at high speed and impose upon he Working s rvh li tres ih y a tend toward imperfection in printing unless counteracted by additionalandjerpensive means.

As a result it has been" necessary to provide especially strong and massive driving, operating and supporting mechanism to insure proper operation of the pressat the desired speed despite the great mass of moving parts 'andto effectively counteract the tendency of the bedto skew. in turn has undesirablyincreased the cost and size of presses as well as the expense of operation due to power merit parts.

l I provide a simple and efiicient' bed motion well consumption j and cost of j replaceadapted for high speed operation in which the mass of the bed and associated mechanism is greatly reduced and the beddriving mechanism acts on the bed in such away as toavoid any substantial tendency toward skewing. I eliminate entirely the use of bedhangers andprovidebed driving means of comparatively-very light weight, greatly reducing the dead Weight-of-the bed and making possible high speed operation employing a minimum of power. I may use a substantially smaller motorthan would otherwisebe necessary,

and in general the press may be more lightly olesigned, resulting in ansimportantrsaving' in first cost and cost of upkeep and o aeration.

I preferably provide "separate means for driv-.

ing the bed during constant speed motion and for reversing the bed at the ends of its stroke.

I provide for drivingslthe bed duringconstant speed motion by applying thewdrivingforceto 2 the bed in such a way as to avoid any substantial tendency to skew the bed. Desirably I provide an elongated operating member adapted to be carried by the bed to lie generally in a longitudinal plane perpendicular thereto and containing the center of gravity thereof and means coacting with said member to drive the bed in both directions of oscillation. The elongated operated member may convenientlytake the form of a rack, and the means coacting therewith may conveniently take the form of pinion means. For example, I may employ two pinions rotating in opposite directions, and bring such pinions alternately into mesh with the rack to drive the bed during constant speed motion. The pinions may be geared together in such manner that when one of them turns in either direction the other turns in the opposite direction. Means may be provided for shifting the pinions transversely of the rack to bring first one and then the other into mesh with the rack.

Desirably the pinions for driving the bed during constant speed motion are out of mesh with the rack at the ends of the stroke of the bed when it is being reversed. This may be accomplished by providing the rack of such length that its trailing end passes out of mesh with the pinion which has been driving it during constant speed motion of the bed before or at approximately the instant when the bed beginsto slow down for reversal.

As above indicated reversing of the bed is desirably accomplished by means separate from the means above referred tofor driving the bed during constant speed motion. I preferably provide an elongated operating member adapted to be carried by the bed and means coacting with such elongated operating member for slowing down, stopping and reversing the bed at at least one end of its oscillatory movement. The elongated operated member may conveniently take the form of a rack and the means coacting there with may take the form of a pinion meshing therewith after the rack through which the bed is driven in constant speed motion has passed beyond the driving pinions coacting therewith. I find it desirable to render operative the bed reversing means at approximately the same time" as the means for driving the bed in constant speed motion are rendered inoperative. The two 3 1 preferably employ similar bed reversing mechanisms for reversing the bed at the respective ends of its stroke.

Reversal of the bed is preferably accomplished by oscillatory means moving at first in synchronism with the bed at the end of its constant speed motion,, the oscillatory means being slowed to a stop and then moved back in the opposite direction to reverse the bed. The oscillatory means may take the form of a crosshead operated by a crank, the crosshead carrying a rack meshing with a gear or segment which in turn is connect ed, directly or through intermediate gearing, with the pinion meshing with the rack on the bed which is used for bed reversal. I find it convenient to employ a single oscillatory member consisting of a crosshead operated by a crank, the crosshead carrying two racks respectively connected through gearing to act on the pinions which mesh with the racks connected with the bed for effecting reversal of the bed at the respective ends of its stroke. 7 A Other details, objects and advantages of the invention will become apparent as the following description of a present preferred embodiment thereof proceeds. V

In the accompanying drawings I have shown a preferred embodiment of the invention, in which Figure 1 is a vertical transverse cross-sectional view through a portion of a printing press show ing the bed motion; m

Figure 2 is a plan view ofthe bed motion; and

Figures 3 to 10, inclusive, are diagrams showing the positions of certain of the parts at various stages during the press cycle, as follows:

Figure 3 shows the bed at the end of its cons'tant speed motion toward. the left on the return or non-printing stroke, the bed being ready to slow down;

. Figure 4 shows the bed stopped at the end of the return stroke ready to move toward the right on the impression or printing stroke;

Figure 5 shows the bed moving toward the right on the impression stroke and at the beginning of constant speed motion;

Figure 6 shows the bed in the middle of constant speed motion moving toward the righton the impression stroke; A

Figure 7 shows the bed at the end of its constant speed motion toward the right on the impression stroke and ready to slow down;

Figure 8 shows the bed in its extreme right hand position at the end of the impression stroke and ready to move back toward the left on the return stroke; I

Figure 9 shows the bed at the beginnin of constant speed motion, on the return stroke;

Figure 1c shows the bed in the middle'of constant speed motion on the return stroke.

Referring now more particularly to the draw ings, there is shown at 2 the impression cylinder of a fiat bed and cylinder press and at 3 the'bed of the press. The press may operate in conventional manner, the cylinder rotating continuously in the same direction (counterclockwise in Figures 3-10) and making two complete revolutions for each cycle of the bed; that is, the cylinder rotates once while the bed is moving forward on the impression or printing stroke and once while it is moving back on the return stroke. When the bed moves forward on the impression stroke the cylinder cooperates with the bed in printing. On the return stroke of the bed the cylinder while continuously rotating in the forward direction is raised relatively to the bed so that it does not contact the bed, as shown, for example, in Figures 9 and 10. This is the standard method of operation of flat bed and cylinder presses and the mechanism for raising and lowering the impression cylinder during operation is well known.

Connected with the cylinder 2 coaxially therewith and having a pitch diameter equal to the diameter of the cylinder is a cylinder driving gear 4. The cylinder driving gear 4 meshes with an idler pinion 5 rotatably carried on a stub shaft 6 mounted in the press frame I. J ournaled for rotation in the press frame is a shaft 8 to which is keyed a gear 9 meshing with the pinion 5. Also keyed to the shaft 8 is a gear ID.

Journaled for rotation in the press frame is a shaft H to which is keyed a flywheel l2. Also keyed to the shaft is a pulley I3. The press is driven by an electric motor (not shown) which drives a pulley M. A series of V belts |5 are trained about the pulley l3 and I4. Thus when the motor is operated it rotates the pulley l4 which through the belts l5 causes rotation of the pulley is. This turns the flywheel shaft H.

Keyed to. the flywheel shaft II is a pinion I6 which meshes with the gear I!) keyed to the shaft 8. Thus the motor through the shaft drives the shaft 8 continuously in the same direction; and the shaft 8 through the gear 9, the pinion 5 and the gear 4 rotates the impression cylinder 2 continuously in the same direction.

Mounted in the press frame for rotation and also for axial movement is a shaft Pinned to the shaft I! are two spaced apart collars H3. Mounted on the frame is a bracket I!) to which is pivoted at 20 a lever 2| whose upper end is bifurcated and carries opposed rollers 22 positioned between the collars l8 and of such diameter as to simultaneously engage said collars, as shown in Figures 1 and 2. The lower end of the lever 2| carries a cam follower roller 23 which operates in a cam groove 24 of a rotary cam 25 keyed to a shaft 26 rotatably mounted in the press frame. Also keyed to the shaft 26 is a gear 2''! which meshes with a pinion 2B pinned to the shaft 8. Thus upon rotation of the shaft 8 the cam 25 is caused to rotate continuously, and that cam through the cam groove 24 and the cam follower roller 23 causes the lever 2| to oscillate about the axis of its pivotal connection 20 with the bracket |9. But as'the rollers 22 carried by the lever 2| are positioned between and in contact with the collars H! which are pinned to the shaft I! the angular oscillation of the lever 2| causes axial oscillation of the shaft IT. The cam groove 24 is designed to oscillate the shaft I! from one extreme position to the other when the bed iS adjacent each end of its stroke, that is, after conclusion of the constantspeed motion of the bed in each direction. During the constant speed motion of the bed the cam follower roller 23 dwells in a circular portion of the cam groove 24 to hold the shaft |8 in one or the other of its extreme axial positions. The reason for axial shifting of the shaft I! will presently'appear.

Mounted on the shaft I1 is a pinion 29 which is always in mesh with the gear ln'regardless of the axial'position of the shaft H. To insure that the pinion 29 will-always remain in mesh with the gear ID the former is made with a wide face as shown in Figures 1 and 2. I prefer to pin the pinion 29 to the-shaft H as shown at 30 in Figure 1 so as to cause the shaft I! to rotate during operation of the press. While it is not necessary that the shaft I! rotate this is desirable because of its endwise movement. If the shaft is turning it will move endwise in its bearings much more freely than if it were non-rotative.

Positioned on the shaft ll adjacent the pinion 29 is a pinion 3| which is of the same diameter as the pinion 29. The pinion 3| is designed to rotate relatively to the shaft l1, wherefore a bushing 32 is interposed between the pinion 3| and the shaft. A collar 33 is pinned to the shaft l1 and maintains the pinion 3| and the bushing 32 in place on the shaft I! in fixed axial position relatively to the pinion 29. Between the pinions 29 and 3| is a frame or spider 34 (Figures 1, 2 and :3) having three radial shafts 35 equally spaced angularly about the frame or spider with a bevel pinion 36 mounted on each shaft 35. Fastened to the pinion 29 by screws 31 is a bevel gear 38.

Fastened to the pinion 3| by screws 39 is a bevel gear 49 of the same size as the bevel gear 38. The

bevel gears 38 and 49 mesh with the bevel pinions 36 of the spider 34.

The spider 34 has a projection 4| extending out between the pinions 29 and 3| which projection has its end bifurcated as shown at 42 in Figure 3 to embrace a rod 44 mounted in the press frame. This prevents the spider from turning about the axis of the shaft l I. The spider is likewise maintained in fixed position axially of the shaft ll so that it partakes of the axial movements of that shaft along with the pinions 29 and 3|. When the shaft |'l moves axially the. bifurcated end 42 of the projection 4| slides along the rod 44.

Since the spider 34 is held against turning, and since the bevel pinions 36 mesh with the bevel gear 38 carried by the pinion 29 and also with the bevel gear carried by the pinion 3|, the pinions 29 and 3| will always be caused, when one of them is driven, to rotate in opposite directions at the same speed. The pinion 29, being pinned to the shaft ll, has no movement relatively to the shaft, but the pinion 3| rotates in the direction opposite the direction of rotation of the shaft, the relative rotational speed of the pinion 3| and the shaft being double the rotational speed of the shaft.

Fastened to the under face of the bed 3 is an elongated operating member in the form of a downwardly facing rack 45. The rack 45 extends parallel to the length of the bed and parallel to the direction of oscillation of the bed. It is preferably disposed to lie generally in a longitudinal plane perpendicular to the bed and containing the center of gravity thereof. If the bed is transversely symmetrical the rack 45 is preferably disposed at the longitudinal center line thereof. The reason for thus disposing the rack 45 is to avoid any substantial tendency toward skewing of the bed when it is driven during constant speed motion, especially on the impression stroke. The rack 45 is adapted to mesh alternately with the respective pinions 29 and 3| during constant speed motion of the bed in its respective directions of oscillation, the length of the rack being such that substantially at the end of the constant speed motion of the bed in each direction its trailing end will pass beyond and hance out of mesh with that one of the pinions 29 and 3| with which it was last in mesh. While the rack 45 is out of mesh with the pinions 29 and 3| other mechanism, presently to be described, effects reversal of the bed. When the bed next reaches the point at which it is to commence its constant speed motion the leading end of the rack 45 comes into mesh with the one of the pinions 29 and 3| which is to mesh with it during such constant speed motion.

The function of the pinions 29 and 3| is to drive the bed during constant speed motion. One of those pinions drives the bed in one direction of oscillation and the other drives it i the opposite direction of oscillation. When the pinion 29 is in mesh with the rack 45, as shown in Figure 1, that pinion drives the bed during constant speed motion in one direction. After the trailing end of the rack 45 has passed out of mesh with the pinion 29 the cam 25 shifts the shaft l1 axially toward the left, viewing Figure 1, to move the pinion 29 laterally out of the path of the rack 45 and the pinion 3| into such path. While, this shifting is taking place the bed is being reversed, and when it reaches the stages on the next oscillatory movement when it is ready to. begin its constant speed motion the forward end of the rack enters into mesh with the pinion 3|, which pinion through the rack 45 drives the bed. during constant speed motion in that direction. The shaft ll always turns in the clockwise direction when one looks at it axially from its left hand end viewing Figure 1 so the pinion 29 drives the bed toward the viewer in Figure l or toward the right viewing Figures 5, 6 and '7, while the pinion 3| drives the bed away from the viewer in Figure 1 or toward the left viewing Figures 3, 9 and 10.

The linear speed of the pinions 29 and 3| at the pitch lines thereof is equal to the speed of the bed during constant speed motion. When the bed nears the end of its stroke and the rack 45 passes out of mesh with the pinion 29 or 3| which has been driving it the bed is slowed up, stopped and reversed, and by the time the leading end of the rack 45 comes into mesh with the pinion ,29 or the pinion 3| on the succeeding oscillatory movement of the bed the speedof the bed will have been brought up to approximately the speed of its constant speed movement, where upon control of the bed is again taken over by the mechanism which has been described.

The mechanism for reversing the bed at the ends of its stroke will now be described. .The shaft [3 rotates in bushings 46 which are disposed in hearings in the frame and two of which bushings extend axially within the hubs of pinions 47 and 49 which are rotatable thereon (Figure 1). The hub of the pinion 4'6 is provided with an annular groove 49 receiving a projection 59 ofta member 5| bolted to the frame by a bolt 52:, whereby to hold the pinion 41 against movement relatively to the frame axially of the shaft ll. Similarly the pinion 49 is held against movement relatively to the frame axially of the shaft I! by a plate 33 fastened by a screw 54 to the frame and entering an annular groove 55 in the hub of the pinion 48. i i

The pinion 41 meshes with a segment 59 rotatable upon a bushing 51 disposed about the shaft 8, which segment 59 is integral with a seg-. ment 58 of smaller diameter and disposed 013-. posite the segment 59. The pinion 48 meshes with a segment 59 rotatable upon a bushing 39 disposed about the shaft 8, which segment 59 has connected therewith by screws 9| a segment 62 of a diameter equal to thediameter of the seg ment 58 and facing in the same directionasthe segment 59.

Fastened to the under side of the bed 3 are two relatively short longitudinally extending racks 63 and 94. The racks 63, 64 and 45 are all parallel to one another, thejrack 63 being disposed adjacent one end of the rack 45 andovera lapping it slightly (about three teeth) and the rack 64 being disposed adjacent the other end of the rack 45 and overlapping it to about the same extent. The pinion all is adapted to mesh with the rack 53 when the bed is at and adiao'ent one end of its movement, and the pinion 48 is adapted to mesh with the rack (it when the bed is at and adjacent the other end of its movement. The function of the pin- ions 41 and 5 8 is to reverse the bed, one of them reversing it each time it 'is at one end of its stroke and the other reversing at each time it is at the other end of its stroke. As the bed moves in each dircction and passes the point at which the trailing end of the rack l-5 leaves the one of the pinions 29 and ti which has been driving it during its constant speed movement on that stroke one of the racks E3 and M is inmesh with its corresponding reversing pinion. The reversing pinion s'lo'wsto a stop and then turns in the opposite direction, causing reversal of the bed. The re versing pinion controls the bed until one of the constant speed pinions 29 or 3! takes charge, at which time the reversing pinion passes out of mesh with the short rack with which it coop-- erates in effecting reversal of the bed.

To accomplish their functions the pinions 4? and 18 must partake of angular oscillation. 'The means for imparting such oscillation to these pinions will now be described. Mounted in the frame is a shaft "85 carrying a gear '66 which is always in mesh with the gear so. Integral with the gear 66 and projecting laterally from a face thereof eccentricallyfthereof is a pin 67. When the gear '66 rotates the pin 61 thus partakes of crank motion. Mounted for rectilinear movement in the frame is a slide '68 comprising a crosshe'ad 69 having therein a vertical slot it in which the crank pin 67 operates The crank pin 61 carries a slide block it which as the gear 66 rotates slides up and down in the slot 70 of the crosshead 6.). "The slide '88 has a guide rod 72 which is received by a guide l3 carried by the frame. The slide also carries t-Wo racks i l and 1'5, the former racing upwardly and meshing with the-segment 58 and the latter facing downwardly and meshing with the segment 62. The slide also has supporting and guiding portions 16 for s1idably supporting it on the shaft 8.

As'the-geart'S rotates the crank pin 61 and the slide block "H partake of crank motion and cause the ciosshe'ad 69 to move back and forth with simple harmonic motion. Since the rack 14 is always in mesh with the segment 58 and the "rack T5 is 'alw'ays in mesh with the segment 52, these segments and also the segments 56 and 59 are constantly being angularly oscillated, and since the latter mentioned segments are always in mesh with the pinions 41 and '48 these pinions likewise constantly partake of angular oscillation. As indicated above the timing is such that each reversing pinion takes control of the bed at the end of constant speed movement of the bed in one direction, brings the bed to a stop and moves it back in the opposite direction until itattains'approximatelythe speed of its constant speed movement, whereupon the means for driving the bed in constant speed movement take control.

A complete cycle of movement of the bed is illustrated in Figures 3 to 10, inclusive, which show the relation of the parts at various stages throughout the cycle.

'The be'd carries plates H which ride upon roller 18 which intu'rnare mounted in tracks"!!! carried by the press frame whereby the bed is mounted for antifrict'ion movement. It is guided in its oscillatory movement by opposed guides coopcrating with portion of the press frame.

By the mechanism described the operation of the bed is eifected and controlled in a remarkably advantageous manner, eliminating entirely the heavy hangers and cooperating parts heretofore customarily employed and which have necessitated massive design of the entire press, especially when it is intended for high speed opera.- tion. My bed motion provides for relatively light design of a press for given duty and given speed, resulting in a very large saving in first cost, cost of operation and costof replacement parts as well as an important saving in space requirements. While I have shown and described a present preferred embodiment of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied within the scope of the following claims.

1. Operating mechanism for a printing press or the like having an oscillating element such as a bed comprising a rack adapted to be carried by the oscillating element, a driving gear continuously rotatable in one direction, 'a first pinion continuously in mesh with the driving gear and also adapted to meshwith the rack to drive the oscillating element in one direction of oscillation, a second pinion, connections between the two pinions independent of the driving gear whereby tl-ie second is driven from the first but to rotate the opposite direct-ion and means for relatively moving the pinions and rack transversely "of the rack to bring the second pinion into and the first pinion out of mesh with the rack to drive the oscillating element in the opposite direc tion of oscillation;

2. Operating mechanism tor a printing press or the like having an oscillating element such as a bed comprising an elongated operating member adapted to be carried by the oscillating element, a sh'ait, a pair of rotatable members mounted on said shaft, each of said rotatable members car rying a bevel gear, a frame mounted on said shaft, the frame carrying a bevel pinion meshing with both of said bevel gears, said rotatable members and said frame being held against axial movement relatively to said shaft, means for rotating one of said rotatable members, means for moving said shaft axially to shift said rotatable members relatively to said elongated operating member to bring said rotatable members alternately into coacting relationship with said elongated operating member and means for holding said frame against rotation whereby said rotatable members will rotate in opposite directions when one of them is rotated and will respectively coact with said elongated operating member to drive the oscillating element in its respective directions of oscillation.

3. Operating mechanism for a printing press or the like having an oscillating elementsuc'h as a bed comprising an elongated operating member adapted to be carried by the oscillating element, a pair of 'rotatab'l'emembers, connections between said rotatable members to cause them when one of them is driven to turn in opposite directions, said rotatable members being adapted selectively to coact with said elongated operating member to drive the oscillating element in its respective directions of oscillation, means for shifting said rotatable member's relatively to said elongated operating member to bring said rotatable members alternatively into coacting relationship with said elongated operating member and a driving member separate from said connections ccacting with one of said rotatable members to drive it in all positions thereof.

4. Operating mechanism for a printing press or the like having an oscillating element such as a bed comprising a rack adapted to be carried by the oscillating element, a pair of pinions, connections between said pinions to cause them when one of them is driven to turn in opposite directions, said pinions being adapted selectively to mesh with said rack to drive the oscillating ele-- ment in its respective directions of oscillation, means for shifting; said pinions relatively to said rack to bring said pinions alternately into mesh with said rack and a driving gear separate from said connections at all times meshing with one of said pinions to drive it.

5. Operating mechanism for a printing press or the like having an oscillating element such as a bed comprising an elongated operating member adapted to be carried by the oscillating ele ment, a shaft, oppositely rotatable members mounted on said shaft and adapted selectively to coact with said elongated operating member to drive the oscillating element in its respective directions of oscillation, connections between said oppositely rotatable members through which one thereof drives the other thereof, a pair of spaced collars on said shaft, a lever fulcrumed at a point spaced from said shaft and having a portion disposed between said collars and means for swinging said lever about its fulcrum to move said shaft to bring said oppositely rotatable members alternately into coacting relationship with said elongated operating member.

6. In a device of the character described, the combination with a frame of an oscillatable member on the frame, a shaft, means for rotating the shaft in one direction of rotation, a gear on the shaft and connected therewith so as to rotate therewith when the shaft rotates, another gear on the shaft rotatable relatively to the shaft, means driven by the shaft for rotating the second mentioned gear in the direction of rotation opposite that in which the shaft is rotated and shifting means for rendering the first mentioned gear and the second mentioned gear alternately operative for displacing said oscillatable member.

7. In a device of the character described, the

combination with a frame of an oscillatable member on the frame, a shaft, means for rotating the shaft in one direction of rotation, a gear on the shaft and connected therewith so as to rotate therewith when the shaft rotates, another gear on the shaft rotatable relatively to the shaft, means including gearing driven by the first mentioned gear for rotating the second mentioned gear in the direction of rotation opposite that in which the shaft is rotated, means holding both gears against movement relatively to the shaft in the axial direction and means for shifting the shaft in the axial direction to render the respective gears alternately operative for displacing said oscillatable member, the means for rotating the shaft being arranged so as to be operative throughout the range of axial movement of the shaft.

8. In a device of the character described, the combination with a frame of an oscillatable member on the frame, a shaft, means for rotating the shaft in one direction of rotation, a gear on the shaft and connected therewith so as to rotate therewith when the shaft rotates, another gear on the shaft rotatable relatively to the shaft, means driven by the shaft for rotating the second mentioned gear in the direction of rotation opposite that in which the shaft is rotated, oppositely moving synchronously timed oscillatable means for operatively displacing the oscillatable member at the ends of its stroke, means on the oscillatable member for connection with said oscillatable means when both of said gears are inoperative with respect to the oscillatable member and shifting means for rendering the first mentioned gear and the second mentioned gear alternately operative for displacing the oscillatable member intermediate the ends of its stroke.

JOSEPH SINKOVITZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 477,200 Crowell June 21, 1892 477,738 Crowell June 28, 1892 1,559,962 Heinitz Nov. 3, 1925 1,810,130 Collyer June 16, 1931

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