US1811139A

US1811139A - Bed driving mechanism for bed and cylinder presses

Info

Publication number: US1811139A
Application number: US368225A
Authority: US
Inventors: Laubach Howard Evans
Original assignee: DELPHOS PRINTING PRESS CORP
Current assignee: DELPHOS PRINTING PRESS CORP
Priority date: 1929-06-04
Filing date: 1929-06-04
Publication date: 1931-06-23
Anticipated expiration: 1948-06-23

Description

June 23, 1931. H. E. LAUBACH 1,811,139

BED DRIVING MECHANISM FOR BED AND CYLINDER PRESSES Filed June 4. 1929 5 Sheets-Sheet 1 H. E. LAUBA'CH 1,811

Filed June 4, 1929 5 Sheets-Sheet 2 BED DRIVING MECHANISM FOR BED AND CYLINDER PRESSES 7/ i a "W m m 2 Y .I A n f 2 8 r m a -W//////////////% E I n v WA/\\\\\\\\\\\\\\\\\- Q I mm J r u Q7 2 I; W a .m I i w m 2 I|.. I YT. .W 4; q w\ v%m W .F/ mw w I w 5 m m m 5:52;: 7 m: a 6 6 June 23, 1931.

June 23, 1931. H. E. LAUBACH 1,311,139

BED DRIVING MECHANISM FOR BED AND CYLINDER PRESSES Filed June 4, 1929 5 Sheets-Sheet s ATT RN;

June 23, 1931. H. LAUBACH 1,811,139

BED DRIVING MECHANISM FOR BED AND CYLINDER PRESSES Filed June 4, 1929 5 Sheets-Sheet 4 INVENTOR.

.June 23, 1931. H. E. LAUBACH 1,311,139

BED DRIVING MECHANISM FOR BED AND CYLINDER PRESSES 5 Sheets-Sheet 5 iled June 4, 1929 I N VEN TOR;

Patented June 23, 1931 UNITED STATES "PATENT orrlci:

HOWARD EVANS LAUBACH, OF CINCINNATI, OHIO, ASSIGNOR TO DELlPl-IOS LPRINTING PRESS CORP., OF PROVIDENCE, RHODE ISLAND, A CORPORATION OF DELAVARE' BED DRIVING MECHANISM FOR BED AND CYLINDER PRESSES Application filed June 4, 1929. Serial No. 368,225.

This invention relates to machines such as bed and cylinder sheet printing presses in which a reciprocating bed, or like member, is employed. The primary object of this invention is to provide means for increasing the speed of such types of presses by reducing the weight of the reciprocating parts.

Heretofore in such presses the greater part of the reversing mechanism has been attached to the bed and reciprocated therewith, such reversing mechanism in some cases weighing as much as the bed itself, but in my invention the only part of the reversing mechanism carried by the bed are two short and comparatively light racks, the remaining and major-parts of the reversing mechanism being mounted upon the frame of. the press in dependently-of the bed. Further in my invention, the only part of the mechanism for driving the bed on the major port-ions of its strokes that is carried by the bed, is a single rack, and the rest of the bed driving mechanism is mounted upon the frame of the press independently of the bed. Therefore in my invention the only parts of the driving and reversing mechanisms carried by the bed are one long and two short racks, while the major and heavier parts of both the reversing and the driving mechanisms, which have heretofore been carried by the bed, are mounted upon the frame. This lightening of the bed greatly lessens the power required to operate it, and enables the greater speed.

Another object of the invention is to provide novel means for reciprocating the bed and reversing its movement at the end of each stroke thereof whereby the reversing means will be relieved of all possible load and not be subject to jar or labor during the period of reversal, thereby permitting the press to be operated at a higher rate of speed.

The various features of the invention will be set forth in the following description of the press illustrated in the accompanying drawings which show anembodiment of my invention as applied to a flat bed cylinder press, and will enable others skilled in the art to adopt and use its same. In the claims are summarized the essentials of the invention,

press to be operated at and novel-features of construction and novel combinations of parts for which protection is desired.

In said drawings:

Fig. 1 is a top plan view of a press with the 1 cylinder and bed removed, and part of the na frame broken away.

l ig. 2 is a transverse vertical section through the press on the'line 22 Fig. 1.

Fig. 3 is an enlarged sectional view of the main driving gears.

Fig. 4 is a diagrammatical sectional view of the press showing the bed at'the point of completing its front reversal and starting on its uniform travel during its impression or printing stroke. 7

Figs. 5 6 and 7 are similar views showing the various positions for thebed during a complete cycle of its movement I Fig. 8 is a detail sectional view.

The inventionis illustrated as applied to a flat bed cylinder press which may be of usual construction and has a main frame 1 provided with ways 2 supporting the reciprocating bed 31, which coacts with the customary printing cylinder (Fig. 2) which is preferably rotated continuously in one direction, and cooperates with the bed as the latter moves in one direction, but is thrown off 1111- pression or raised so as not to contact with .the'bed during the return stroke of the bed by the usual means, not shown.

The bed 31 is provided on its underside with a longitudinally disposed rack 33, which is the main bed driving rack, and is meshed on the printing stroke with the bed driving gear 8 and on the return stroke with the bed driving gear 9. The bed also has short reversing racks 32 and32a on its under side,arranged at the ends of and parallel with rack 33 but to one side ofthe plane thereof.

Racks

32, 32a are adapted to mesh with a reversing gear 10. The gear 9 has a sleeve hub 9a which surrounds shaft 7 and is ournaled in a bearing 39 attached to the frame; and shaft 7 and has a bearingin the hub of gear 9a. A grooved collar .14 is pinned toshaft 7 at one end of sleevehub 9a, the gear 9 being confined between gear 8 and collar 14 against'longitudinal movement on shaft 7. The reversill) 7 frame 2 and the journal 39., see Fig. 2.

ing gear is shown as rotatably mounted on the inner end of the bearing 11 in which the inner end of shaft 7 is journaled.

Gears

8, 9 and 10 are in axial alinement, and preferably of the same diameter. The gear 8 is fixedly mounted on a shaft 7 journaled in

suitable bearings

11 and 12 on the frame below the ways 2.

A gear 5 is mounted upon an extension 12a of the bearing 12, and meshes with a pinion 4 on the drive shaft 3 which is journaled in the frame parallel with the shaft and may be driven by any suitable means. As shown it has a belt pulley 38 on its outer end.

The shaft 7 is longitudinally movable so as to shift

gears

8 and 9 alternately into and out of position to mesh with the rack 33. The shaft 7 is rotated by means of spider arms 6a attached to a hub 6 fast to the outer end of the shaft 7 and having their ends bent parallel with th shaft 7 and engaged in slots 5a in a gear 5 journaled on a sleeve stud attached to the frame (see Jigs; 1 and 3) thereby insuring uniform rotation of shaft 7 with the gear 5 and at the same. time permitting shaft '7 to move bodily endwise so as to shift

gears

8 or 9 into and out of position to engage and mesh with gear 33.

The shaft 7 may be shifted longitudinally at the proper time by any suitable means. As shown the groove in collar 14 is engaged by pins on a yoke 15 which is mounted on a bracket 15c attached to the frame. The other arm 15b of yoke 15 has a roller 17 which engages a groove in a cam member 16 fast on a shaft 37 journaled in the framing parallel with and below shaft 11. haft 37 has a gear 19 on its outer end meshing with pinion 18 which is fast to'the hub of the gear 5 and rotat d therebv.

Thehub of gear 9 is preferably multi-splined and on this end is mounted a pinion 13 which meshes with a pinion 23 on a short shaft 22, mounted in the frame intermediate the

sha ts

3 and 7. The pinion 13 is confined against longitudinal movement by a boss on the way Shaft 22 has a gear 21 on its outer end meshing with pinion on shaft 3. Pinion 13 drives gear 9 continuously in one direction but permits the shaft 7 with gears S and 9 and collarle to be shifted freely longitudinally while being rotated positively in their respective directions by the gear 13, and arms 6a, gear 9 rotating continuously clockwise and shaft 7 and gear 8 rotating continuously anti-clockwise, but both

gears

8 and 9 shifting freely and siinultaneously longitudinally.

through

pinions

20, 21, 23, 13 direct to gear 9. The gear 9 rotates clockwise in a direction opposite to gear 8 and thus moves the bed outward on its idle or return stroke, say to the right; while the gear 8 rotating anti-clock wise will drive the bed inward to the left on its printing stroke.

The rack 33 is of such length that it will run out of mesh with the gear 8 just when the bed nearsthe end of its printing stroke; and will run out of mesh with gear 9 when the bed nears the end of its return stroke; and during the time that both

gears

8 and 9 are out of mesh with the rack 33, the bed must be slowed down, stopped and started back in the opposite direction, or reversed as it is commonly termed.

The reversals are effected by means ofa

short rack

32 and 32a which is attached to the underside of the bed adjacent the opposite ends of rack 33 and engaged with gear 10 preferably corresponding in diameter and in axial alinement with gear 8. The racks; 32 and-32a are so disposed with reference to rack 33 that just before gear rack 33 runs out I of mesh with gear 8 gear 10 will mesh with rack 32 and take control of the bed; and just as gear 10 goes out of mesh with rack 32. gear 9 meshes with rack 33 and takes control of the bed and moves it to the left and just shaft '7 will be shifted longitudinally to move gear 8 out of position to mesh with rack 33 and bring gear9into position to mesh therewith; and during the period of reversalatthe outer end of the returnstroke while gear 10 is engaged with rack 32 the shaft 7 willbe shifted by cam 16 to move gear 9 out of position to mesh with rack 33 and gearB into position to mesh therewith. The gearslSand 19 are so proportioned as to rotate cam 16 and cause it to shiftshaft7 and gears 8 and 9 as above described during the respective reversal periods. j I

As stated gear 10 has an oscillatinginotion which is imparted'to it by means ofa longitudinal rack 36 which is supported-in guide 3656 mounted on the main frame, see Fig.2. As shown rack 36 is attached at one end toa vertically disposed scotch yoke 28 which is engaged by slide block 27 mounted on a crank pin 26 attached to a gear2-5 attached to a shaft journaled insuitablebearings.on the frame. (See Figs. 1 and2). The gear 25 meshes with pinion 24 on the driveshaft 3 and the'parts are so. proportioned that; gear 10 will be caused to move in the same diTQC'.

tion and at the same speed as gear 8 at the moment of time when gear 8 is run. ning out of or into mesh with rack 33 and gear 10 going into or outof mesh with rack 32-or 32a. As soon as gear 8 is out of mesh with rack 33 gear 10 will be slowed down by the arcuate movement of pin 26, (see Fig. 3) until it comes to a dead stop and then begins to turn reverse direction with accelerating speedunt-il just at the moment gear 10 runs out of mesh with rack 32a gear 9 comes into mesh with rack 33 and takes control of the bed. Just before gear 9 runs out of mesh with rack 33 gear 10- is again accelerated to a speed corresponding to gear 9 and runs into mesh with gear 32a and takes control of the bed when gear 9 goes out of mesh with rack 33, and then gear 10 is slowed down to stop the bed and then start the bed moving in theopposite direction and speed it up until the moment gear 10 runs out of mesh with rack 32!; gear 8 comes into mesh with rack 33 and takes control of the bed. During the printing stroke the bed 31 isdriven by the gear 8 meshing with rack 33 and during the idle or. return strokethe bed 31 is driven by gear 9 meshing with rack 33.

In Fig. ethe bed 31 has just been reversed by gear 10 meshing with rack 32. At this point the rack 32 ends and rack 33 which is mounted to the side of rack 32 meshes with gear 8. Gear 8 Will now drive the bed 31 to position shown in Fig. 5 where rack 33 ends and rack 32a begins. At this point the gear 10 will be rotating in the same direction as gear 8 and at the same peripheral speed, due to the throw of crank 26 being the same as the pitch diameter of gear 10.

Fig. 6 shows the bed 31 at its extreme travel, and point of theoretical dead rest, fronrwhich point it will move with increasing speed in the opposite direction. During this period of reversal the shaft 7 driven by the arms 6and gears 8 and 9 and collar 1% will be shifted axially by the cam 16 through lever 15 so that at the completion of the re versal gear 9 will be in line with rack 33. Fig. 7 shows the bed 31 at the end of its reversal now being driven by gear 9 meshing with rack 33, and gear 10 running out of mesh with rack 32. Gear 9 will now movethe bed 31 to the other end of the press,-when gear lO'will again enter rack 32.

I It will be seen that during the period when the crank 26 is carrying the load of the bed 31 the

gears

8 and 9, shaft 7 and arm 6, are entirely free of all load and may be easily shifted. i

- It will be noted from the foregoing descriptionand the drawings that the only parts of the major bed driving mechanism carried by the bed is the single rack 33, and the only parts of the reversing mechanisms carried by the bed are the short racks 32 and 32a. 7 These racks add very'little weight to the bed, and

consequently enable it to be reciprocated at higher speed and with less power than is possible with presses where theparts of the bed driving and reversing mechanism carried by the bed are numerous and heavy,

With the exception of the reversing yoke 28 and rack 36 there is no reciprocation of parts other than the bed. This adds to stability and quiescence in operation. The weight of the reciprocating parts to be consider-ed in driving the'bed is practically the weight of the bed alone. The bed driving gears 8 and 9 and the gear 25 are rotated at constant speed in their respective directions. Gear 10 is oscillated bygear 25 running constantly in its respective direction. 1 The shaft for driving the bed during its printing stroke extends through the gear for driving the led during its return stroke; The cylinder driving gear is mounted on the bearing in which the said bed driving shaft rotates and slides. Gear 5 being mounted as shown relieves the shaft? of all weight'or labor during its shifting but during the printing stroke said gear 5 drives both the bed and the cylinder. The means for shifting the driving gears 8 and 9 permits them to be continuously driven at all times while being shifted. In shifting the gear 13 is preferably confined against longitudinal movement and the gear 9 shifts in the gear 13. The oscillating reversing gear 10 is mounted on a sleeve within which the bed driving shaft rotates and slides. The rack 33 for driving the bed on the major portion of its stroke is only as long as the true or constant travel-of the bed, and

thereversing racks

32 and 32a cooperating therewith insure a full stroke of the bed in each direction. The bed driving rack 33 and reversing racks 32 and 320: are located closely adjacent to the central line of the bed and during the reversing periods the bed driving gears are free from the rack and can be freely shifted axially. The gears for criving the bed in opposite directions are nested and one of teem is driven by means extending axially through the means for driving the other, and both of them can be shifted as a unit during the reversing periods.

I claim:

1. In a printing press a bed, a bed driving rack attached to the underside of the bed, a

bed reversing rack attached to the underside of the bed adj acent each end of the bed driving rack, a pair of bed driving gears, means for independently and continuously rotating said gears in opposite directions, said gears being adapted to drive the bed on the major portions of its strokes, means for shifting said gears axially during the reversal period respectively into and out of position to engage with the bed driving rack, and means cooperating with said reversing racks while the bed driving gears are out ofmesh i with the bed driving rack, to slow down and stop the bed and start it in the reverse direction.

2. In mechanism as set forth in claim 1, the means cooperating with the reversing racks comprising an oscillating gear, a rack bar meshing therewith, a continuously rotating crank and a connection for operating the rack bar from said crank.

3. In mechanism as set forth in claim 1 the means cooperating with the reversing racks comprising an oscillating gear, a rack bar meshing therewith, a scotch yoke connected with this bar, a rotating crank engaging the scotch yoke, and means for driving said crank so as to compel it to make a half revolution during each reversal period. a 4:. In a printing press a bed, a bed driving rack attached to the bed, a bed reversing rack attached to the bed adjacent each end of the bed driving rack, a pair of bed driving gears rotating in opposite directions and adapted to drive the bed on the major portions of its strokes, means to shift said bed driving gears axially during the reversal period into position to engage with the bed driving rack, a gear adapted to mesh with a bed reversing rack at the moment that one bed driving gear runs out of mesh with the bed driving rackand to run out of mesh therewith when the other bed driving gear engages the bed driving rack, and means for oscillating the reversing gear while in mesh with the reversing rack to slow down, stop and start the bed in the reverse direction.

5. In a printing press a bed, a bed driving rack attached to the underside of the bed, a bed reversing rack attached to the under-- side of the bed adjacent each end of the bed driving rack, a pair of bed driving gears, means for independently and continuously rotating said gears in opposite directions, means for shifting said gears to drive the bed on the major portions of its strokes axially during the reversal period respectively into and out of position to engage with the bed driving rack, a gear in axial alinement with the bed driving gears (mounted independently thereof) and adapted to mesh with abed reversing rack during the reversal period, and means for oscillating said reversing gear so that it will come into mesh with a reversing rack at the moment that one bed driving gear goes out of mesh with the bed driving rack, and will run out of mesh therewith when the other bed driving gear engages the bed driving rack; and means for oscillating the reversing gear while in mesh with the reversing rackso as to slow down and stop the bed and start it in the reverse direction.

6. In a printing press, a bed, a bed driving rack attached to the bed, a pair of bed driving gears rotating in opposite directions and adapted to drive the bed on the major extending through said sleeve and carrying the second bed driving gear, a gear concentric with said shaft, means for driving said shaft from the mam shaft; and means for axially shifting the shaft and sleeve and the bed driving gears during the period of reversal and while both gears are. out of mesh with the bed rack.

7. In a printing press a bed, a bed driving rack attached to the bed, a bed reversing rack attached to the bed adjacent each end of the bed driving rack, a pair of bed driving gears adapted to alternately drive the bed on the major portions of its alternate strokes, a rotatable sleeve carrying one of the 'bed driving gears, a shaft on which the second bed driving gear is fast extending through said sleeve, and means for separately driving said sleeve, and means for separately driving said sleeve and said shaft from the main shaft; means for axially shifting the shaft and sleeve and the bed driving gears during the period of reversal and while both gears are out of mesh with the bed rack; and means for reversing the bed while both said gears are out of mesh with the bed rack.

8. In mechanism as set forth in claim 7, said reversing means comprising a gearadapted to mesh with a bed reversing rack as one bed driving gear runs out of mesh with the bed driving rack and to run out of mesh therewith as the other bed driving gear engages the bed driving rack; and means for oscillating the reversing gear while in mesh with the reversing rack to slow down, stop, and start the bed in the reverse direction.

9. In a printing press a bed, a bed driving rack attached to the bed, a bed reversing rack attached to the bed adjacent each end of the bed driving rack; a pair of bed driving gears rotating in opposite directions and adapted to drive the bed on the major portions of its strokes, a rotatable sleeve carrying one of the bed driving gears, a pinion fast to said sleeve, gearing between said pinion and the main driving shaft, a shaft extending through said sleeve on which shaft the second bed driving gear is fast and gearing'for driving said shaft from the main driving shaft; means for axially shifting the shaft and sleeve and the bed driving gearsduring the period of reversal and while both gears are out of mesh with the bed rack, a gear adapted to mesh with a bed reversing rack at the moment that one bed driving gear runs out of mesh with the bed driving rack and-to runout of mesh therewith when the other bed driving gear engages the bed driving rack, and means for oscillating the reversing gear while in mesh with the reversing rack-to slow down. stop .and start the bed in the reverse direction. j

10. In a printing press a bed, a bed driving rack attached to the bed, a bed reversing 6 rack attached to the bed adjacent each end of the bed driving ra-cx, a pair of bed driving gears rotating in opposite directions and adapted to drive the bed on the major portions of its strokes, means to shift said bed 10 driving gears axially during the reversal periodinto position to engage with the bed driving rack, a gear adapted to mesh with a bed reversing rack at the moment that one bed driving gear runs out of mesh with the bed driving rack and to turn out of mesh therewith when'the other'bed driving gear engages the bed driving rack, :1 scotch yoke connected with said bar, a rotating crank engaging the scotch yoke, and means for driv- 2 ing said crank so as to compel it to make a half revolution during each reversal period. 11. In a printing press a bed, a bed drivng rack attached to the bed; a pair of bed driving gears rotating in opposite directions and adapted to alternately mesh said rack and drive the bed on the major portions of its-strokes; a rotatable sleeve carrying one of the bed driving gears, a pinion fast tosaid sleeve, gearing between said pinion and the main .driving shaft, a shaft extending through said sleeve and to which the second bed driving gear is. fast; a gear concentric with said shaft, said shaft having a slidable engagement with said gear, and means for shifting the bed driving gears while both gears are out of mesh with the bed rack.

, 12. In a printing press a bed, a bed driving rack attached to the bed, a pair of bed driving gears rotating in opposite directions 401 and adapted to drive the bed on the major portions of its strokes, a rotatable sleeve carrying one of the bed driving gears, a pinion fast to said sleeve, gearing between said pini0n and the main driving shaft, a shaft extending through said sleeve and to which the second bed driving gear is fast, a gear concentric with said shaft, a yoke fixedly attached to said shaft and having a slidable engagement with said gear; and cam operated i means for axially shifting the shaft and sleeve and the bed driving gears during the period of reversal and while both gears are out of mesh with the bed rack.

: 13. In a printing press a bed, a bed driving rack attached to the bed, a bed reversing rack attached to the bed adjacent each end of the bed driving rack; a pair of bed driving gears rotating in opposite directions and adapted to drive the bed on the major por- "tions of its strokes, a rotatable sleeve carrying one of the bed driving gears, a pinion fast to said sleeve, gearing between said pinion and the main driving shaft, a shaft extending through said sleeve and to which the "second bed driving gear is fast, a gear concentric with said shaft, a yoke fixedly attached to said shaft and having a slidable engagement with said gear; a gear adapted to mesh with a bed reversing rack at the mo ment one bed driving gear runs out of mesh with the bed driving rack and to run out of mesh therewith when the other bed driving gear engages the bed driving rack to slow down, stop and start the bed in the reverse direction, a rack bar meshing with said bed reversing gear, a'scotch yoke connected with this bar, a rotating crank engaging the scotch yoke, and means for driving said crank so as to compel it to make a half revolution dill:- ing each reversal period, and cam operated means for axially shifting the shaft and sleeve and the bed driving gears during the period of reversal and while both gears are out of mesh with the bed rack.

14:. In a printing press a bed, a bed driv ing rack attached to the underside of the bed. a pair of gears rotating in opposite directions adapted to be alternately engaged with said rack; asleeve carrying one of said gears, a rotatable shaft carrying the other of said gears and extending through said sleeve, means for driving the sleeve and shaft in opposite directions, and means for shifting both said gears axially during reversal periods.

15. In a printing press, a bed, a cylinder cooperating Wlbll the bed, a shaft, a bed driving gear thereon adapted to move the bed on one stroke, a cylinder gear, a gear mes ling with the cylinder gear mounted axially of said shaft, a connection between the axially mounted gear and said shaft whereby the cylinder and bed are both moved by said gear during one stroke of the bed; aHsec-ond bed driving gear adapted to move the bed on its return stroke, and means for rotating the latter gear independently of the said axially mounted gear. 7

l6. In a printing press a bed, a cylinder cooperating with the bed, a pair of bed. driv.

ing gears rotating inopposite. directions adapted to alternately move the bed in opposite directions, a sleeve carrying one of said gears, a rotatable shaft carrying the other of said gears and extending through said sleeve, a continually rotating driving gear mounted axially of said shaft, a connection between said gear and said shaft whereby the bed is.

moved by said gear on one stroke of the bed, a gear on the cylinder meshing with said continuously rotating gear, means for driving the sleeve independently of thesaid shaft to move the bed in the opposite direction, and means for shifting said sleeve and both bed driving gears axiallyduring the periods of reversal. r i

17. In a printing press a bed, a cylinder cooperating with the bed, a bed driving rack attached to the underside of the bed, a pair of bed driving gears rotating in opposite directions adapted to be alternately engaged with said rack to move the bed in opposite directions, a sleeve carrying one of said gears, a rotatable shaft carrying the other of said gears and extending through said sleeve, a continuously rotating gear mounted axially of said shaft, a slidable connection between the latter gear and said shaft, a gear on the cylinder meshing with said continuously rotating gear, means for driving the sleeve independently of the said shaft and means for shifting the sleeve and both bed driving gears axially during the period of reversal.

18. In a printing press; a bed, a bed drive rack attached to the bed, a pair of continuing supplemental racks attached to the bed adjacent each end of the bed driving rack and in a different plane; means adapted to engage the bed rack to drive the bed on the major portions of its strokes; a gear adapted to mesh with one of the continuing supplemental racks at the moment that the bed driving means runs out of mesh with the bed driving rack and to run out of mesh therewith when the bed driving means again engages the bed driving rack; and means for oscillating the reversing gear while in mesh with the reversing rack toslow down, stop and start the bed in the reverse direction.

19. In a printing press; a bed; a bed driving rack attached to the bed; a bed reversing rack attached to the bed adjacent each end of and extending beyond the bed driving rack; rotating gears turning in opposite directions adapted to alternately mesh with the bed driving rack and drive the bed on the major portions of its strokes and then run out of mesh; a reversing gear adapted to mesh with the adjacent bed reversing rack at the moment that either bed driving gear runs out of mesh with the bed driving rack, and to run out of mesh therewith when the other bed driving gear engages the bed driving rack; and means for oscillating the reversing gear while in mesh with a reversing rack and cause it to slow down, stop and start the bed in the reverse direction.

20. In a printing press; a bed; a bed driving rack attached to the bed; rotating gears turning in opposite direction adapted to alternately mesh with the bed driving rack and drive the bed on the major portions of its strokes; a sleeve carrying one of said gears, a rotatable shaft carrying the other of said gears and extending through said sleeve; means for driving the sleeve and the shaft in opposite directions; and means adapted to engage the bed at the moment that either bed driving gear runs out of mesh with the bed driving rack and slow down,stop and start the bed in the reverse direction and then disengage the bed when the other bed driving gear engages the bed.

21. In a printing press; a reciprocable bed, a d rack, a pair of bed driving gears,

a sleeve carrying one of said gears, a rotatable shaft carrying the other of said gears and extending through said sleeve, and means for longitudinally shifting the sleeve and shaft to bring either gear into position to mesh with the bed rack.

22. In a printing press; a reciprocable bed, a bed rack, a pair of bed driving gears adapted to cooperate with the bed rack to drive the bed, a slidable sleeve carrying one of said gears, a rotatable shaft carrying the other of said gears and extending through said sleeve and slidable therewith, means for driving the sleeve and the shaft in opposite directions; and means for longitudinally shifting the sleeve and shaft to alternatetly bring the gears into position to mesh wi the bed rack.

23. In a printing press; a bed; a bed driving rack attached to the bed; a bed reversing rack attached to the bed adjacent each end. of the bed rack; a pair of gears turning in opposite direction adapted to alternately mesh with the bed driving rack and drive the bed on the major portions of its strokes and then run out of mesh; a sleeve carrying one of said gears; a rotatable shaft carrying the other of said gears and extending through said sleeve; means for driving the sleeve and the shaft in opposite directions; a reversing gear adapted to mesh with the adjacent bed reversing rack at the momentthat either bed driving gear runs out of mesh with the bed driving rack, and to run out of mesh therewith when the other bed driving gear engages the bed driving rack; and means for oscillating the reversing gear while in mesh with a reversing rack to slow down, stop and start the bed in the reverse direction.

HOWARD EVANS LAUBACH.

Ill