US2280091A - Press bed drive - Google Patents

Description

April 21, 1942. s. A.-HUFFMAN I PRESSY BED DRIVE Filed Aug. 26, 1939 4 Sheet-Sheet 2 INVENTOR I jamuelAf/ufif'man April 21,1942. A UFFMAN 2,280,091

PRESS BED DRIV-E Filed Aug. 26, 1939 v 4 Sheets-Sheet 3 INYENTOR April 21, 1942. s. A. HUFFMAN 2,280,091

PRESSBED DRI-VE Filed 1m 26, 19319 f 4 Sheets-Sheet 4 58/72049/4. Huffman MIM Patented Apr. 21, 1942 UNITED STATE PR E SS BED DRIVE Samuel A. Huflman, Ayalon, Pa., assignor to Miller Printing Machinery 00., Pittsburgh, Pa., a corporation of Pennsylvania Application Au ust 26, 1939, Serial No. 292,105 g 8 Claims.

, This invention relates to mechanism for reap rocating thejbed of a flat bedand cylinder press.

The demand for higher efficiency in press" operation has led to the design ofv presses running at higher and higher speeds, despite certain factors entering into press operation which tend definitely to limit the maximum permissible operating speed. It is the general object of this invention to extend the limit on press speed a novel construction. and arrangement of parts whereby higher operating speeds may be safely attained than with the constructions known heretofore.

The weight of the reciprocating bed is probably 7 the principal limitat on upon press speed, because of necessityfor accelerating the bed from rest to maximum speed and then decelerating it to rest twice during each complete operating cycle. For this reason, attempts havebeen made to reduce the weight of the bed. Here again, however, a limit is imposed by the necessity that the bed be rigid enough to avoid any material deflection under the pressure exerted, thereon by thecylinder. ,Ribbed beds have been resorted to for rigidity butthe permissible depth of the ribs is limited by the clearances necessary between the bed and the reversing gears as previously installed. The location of the reversing gears previously employed,-furthermore, as well asthe character of the reversing hanger carried bythe reducing the deflection of the bed between tracks .by reducing the span between the two inner tracks of a fourtrack press, for example.

Other novel features and advantages of ,the invention will be more fully pointed out hereinafter in the course of the following detaileddescription and explanation in which reference is made to, the accompanying drawings illustrating 'a present preferred embodiment. In the draw ings:

'Fig. 1 is a plan view of a presshaving'thein i vention incorporated therein, showing the parts in position for effecting a return stroke of the f stantially along the bed, have. been such that the inner bed tracks are achieved. In a preferred form of the invene tion, I provide a reversing hanger disposed substantially centrally of the bed cooperating with reversing cranks which. successively engage the hanger near the ends of the press. I also dispose the gear drive for the reversing cranks andpress cylinder on one side of the press. This construction provides a greater depth of free space across the machine below the cylinder than is present in previous press constructions. Forthisreason,

the overall height of the press may be less than was formerly required. The novel construction of thefhanger and reversing cranks, furthermore, v

as well as the location of the reversing gears at one side of the frame, permits the several tracks on which the bed is supported for reciprocation to be spaced substantially uniformly, thereby bed,parts being omittedforclearness; a

Fig. 2 is a sectional view taken'substantially along-the plane of line IL-I Iof Fig. 1, showing the bed at a point inits printing stroke; 7 Fig. 3 is a' sectional view taken along the plane of line III--III of Fig. 1, showing the parts positioned for a return stroke of the bed;

Fig. 4 is a partial sectional view taken sub;- plane of line IV-IV of Fig. 3; and r o Fig. 5 is a View partly in elevation and partly in section along the plane of line V-V of Fig. 4. 7 Referring now in detail to the drawings, a press of the flat bed and cylinder type includes side frames I 0 and II connected at their ends by end castings l2 and I3. The press cylinder 14 has trunnions journaled in bearings l5 mounted in upward extensions. Hi from the side frames l0 and H. The bed IT is supported reciprocably below the cylinder on tracks [8 carried on a cross beam 19. Roller bearings 20 are disposed be tween the tracks l8 and the bed and thelatter is held on-the tracks by gibs 2|. Bearers 22 on the cylinder cooperate with bearers 23 on the bed as the latter passes beneath the cylinder on a first in one direction of rotation upon reciproca- ;;tion of the bed in one direction and then in the opposite direction of rotation upon reciprocation of. the bed in the opposite direction. The bed I! is provided with the usual ink plate 26.

The construction describedso far is conventional and for that reason it is unnecessary to go sprocket 29 is secured to a main drive shaft 36 which is journaled in bearings 3| in the webs of the two tracks I8 nearest the side frame H. A fly-wheel 36a is mounted on the shaft 36. A pinion 32 on the shaft 36 meshes with a bed reversing gear 33 secured to a shaft 34. shaft 34 is journaled in bearings 35 and 36 formed in the side frame II and the adjacent inner track l8. A bed reversing crank 31 is secured to the shaft 34 adjacent its inner end and is provided with a roller 38 journaled on a crank pin 39. i a

The roller 38 is adapted to engage a hanger 46 depending from the bed I1, in a manner to be described further hereinafter. The hanger comprises a ribbed casting having plane bearing surfaces 4| and 42 disposed at angles to the horizontal.

The'pinion 32 also meshes with an intermediate gear43 secured on a shaft 44. Theshaft 44 is journaled in bearings disposed in the side frame II and the webs of one of the tracks 16, in the same manner as the bearings 35 and 36. The shaft 44 has secured to it a gear 43a which meshes with a gear 45 secured to one of the trunnions of the cylinder 14. The gear 43 also meshes with a reversing gear 46 secured to a shaft 41. 'The shaft 41 is journaled in bearings 48 and 49 similar to the bearings 35 and 36 for the shaft 34. The shaft 41 also has a crank 56 at the inner end thereof provided with a crank pin 5| having a roller 52 for engagement with the bearing surface 42 of the hanger 46.

A gear 53 has a grooved collar 54 integral therewith (see Fig. 4) and is splined on a sleeve 55 secured to the shaft 44. The gear 53 meshes with a rack 56 secured to the bed 11 for driving the bed during the constant speed portion of its printing stroke. The gear 53 is shiftedaxially along the sleeve 55 by means to be described shortly while the bed is being decelerated and reversed after a printing stroke. 1

The gear 53 also meshes with a gear 51 se- 7 cured to a shaft 58. The shaft 58 is journaled in bearings 59 in the webs of the two tracks nearest the side frame H and is slidable axially therein by the same means which shifts the I gear53. A gear 66 on the shaft 58 has a grooved collar 6| integral therewith and is adapted to mesh with a rack 62 on the bed l1 to effect the reverse stroke of the latter. 7

A pinion 63 on the shaft 44 meshes with a cam gear 64 secured to a shaft 65. The shaft 65 is journaled in bearings 66 similar to the bearings 59 of the shaft 58. A gear 61 on the shaft 65 has a barrel cam 68 formed integral therewith having a groove 69 therein. A shifter a A shifter yoke 14 pivoted on the beaml6 at 15 has tongues 16 entering the groove in the collar 54 formed on the gear 53. The shifter yokes 16 and 14 are connected by a link 11 pivoted thereto. Rotation of the cam 68 thus causes simultaneous axial shifting of the gears 53, 51 and 66.

The gear 61 meshes with a gear 18 for operating a cam shaft (not shown) or other means for periodically actuating auxiliary control devices such as the valves between the suction feet of the feeder and a vacuum pump (not shown).

The cam gear 64 has a groove 19 formed in one side thereof. A crank 86 is rotatable on a stub shaft Bl secured in the web of the track l8 nearest the side frame II, and has a roller 82 in the groove 19. A gear segment 83 secured to the crank 86 meshes with a pinion 84 secured to a shaft 85. The shaft 85 extends between the side frames I6 and II, being journaled in bearings 86 therein, the webs of the tracks [8 being bored to admit the shaft. The shape of the groove 19 is such that rotation of the gear 64 causes oscillation of the crank 86 and the segment 63. This oscillation is transmitted to the pinion 84 and shaft 85. The latter has eccentrics 81 which, by means of push rods 68, actuate the bearings l5 supporting the trunnions of the cylinderv l4. These bearings are mounted in eccentrics so that partial rotation of the latter raises or lowers the bearings.

In explaining the operation of the press bed drive described above it will be assumed that the bed 11 is at the left end of its stroke as indicated in Fig. 2 in chain lines. The reversing gear 33 being driven clockwise by the motor 21, the roller 38 exerts downward pressure on the bearing surface 4| of the hanger, thereby accelerating the bed for a printing stroke (i. e., toward the right in Fig. 2). After half a revolution of the gear 33 the roller 38 departs from the bearing surface 42 of the hanger and at that instant the rack 56 engages gear 53. The design of the cam 66 and the setting thereof on the shaft 65 is such that the gear 53 is in vertical alinement with the rack 56 at this-in stant. Thus, after being accelerated to maximum speed by the crank 31, the bed moves through the constant speed portion of its travel. During the actual printing portion of the stroke, the cylinder is driven frictionally by its contact with the bearers 23, the teeth of the cylinder gear 45 being appropriately relieved for this purpose.

At the instant when the trailing end of the bed passes the vertical central plane through the cylinder l4, the roller 52 is in the position shown in solid lines in Fig. 2, and is thereupon engaged by the bearing surface 42 of the hanger 46. Continued counterclockwise rotation of the crank 56 through 90 to the position shown in chain lines causes the bed to be decelerated. It is then reversed as the crank passes'beyond the chain line position.

While the bed is being decelerated and reversed by the crank 56, the barrel cam shifts the yokes 16 and 14 to the position shown in Fig. 4, sothat the gear 66 is ready to engage the rack 62 to move the bed through the constant speed portion of its travel on the reverse stroke. This engagement occurs when the crank 56 has rotated to a posi- 3 011 2180 from that in which it is solid lines in The cam groove in the gear 19 causes oscillation ofthe crank 86 and the segment 83 at the proper time tocausethe bearings", l tobe raised so that the cylinder; lkclears the formon the bed when the latter makes its reversestroke.

When thebed hasreached the pointin itslireverse stroke at which the rack 62 passes beyond the gear 60, the roller38 of the crank 31 is in the position shown in solid lines in Fig. 2 and engages the bearing surface 4| "of the hanger to decelerate the bed on continuedclockwiserotationof the reversing gear 33. A full cycle of operations is thus completed and continuedoperation of the drive involves merely a repetition of heretofore. This means that the overall height of the machine maybe reduced. I The drive gears, being located "outside the press frame, may be enclosed' in an oil filled housing; A further advantage of great importance is the fact thatthere are only two gear meshes between the main drive shaft andthecylinder or the thecycle described. It will be understood that the oscillation of theshaft 85 is such as to restore the bearings of the cylinder to the position in which the cylinder hasfirm engagement with the form on the'bed, before the latter reaches the cylinder on the printing strokel It will also be understood that the movement of the bed is positively controlled throughout its stroke in both directions; so that the racks 56 and62 mesh properly with thegears 53 and 60. during the constant speed portion, of the printing and reversingstrokes. It will be apparent that the inventionis characterized by numerous advantages over present bed drives as known heretofore; The use of ahangerhaving both its bearing surfaces in alinement and the disposition of the reversing" gears beyond one side of the press makes it possible to place the inner tracks 18. closer together,

thereby equalizing the, distance between them with the distance between them and the outermost tracks. This shortens the span of .thebed between the inner tracks and limits the deflec tion of the bed during printing. By way of comparison, the inventionpermits the distance betweenthe outer andinner tracks tobe as much as 90% of the distance betweenthe inner tracks as comparedto about 50% forthe previous constructions. The maximum and minimum track spacings for a typical example of my invention are 18 andl'l compared to 25 and 13 for the former construction.

By locating the reversing gears beyond the side frame instead of between the inner track webs, it is possible to use gears of larger diameter, thus reducing-the tooth pressure and permittingthe use of less expensive material such as cast iron,

instead of the more expensive heat treated alloy steels. The reversing gears are subject to the tremendous forces involved in rapid acceleration and deceleration of the bed and their strength is a definite limit upon the operating speed of the press. By virtue of the location of the reversing gears beyond the side frame, the tooth width thereof may be increased, further to reduce the unit pressure, without requiring greater spacing between the inner track webs as would be the case if the reversing gears were located therebetween.

The main driving gears, furthermore, may be of the single or double helical type which are particularly advantageous at higher speeds because of greater strength, quiet operation and freedom of vibration. It is not possible to employ this type of gears in press drives as pre viously constructed.

The closer spacing of the tracks makes it possible to reduce the .overall'depth'of the bedfor a given permissible maximum deflection. This reduces the weight of the bed and raises the maximum safe operating'speed. I

The flywheel shaft is near the centerofthe press, thereby reducing the gear shock transbeds This compares with four ormore meshes in previous drives. The lost motion representing cumulativetooth clearances is thus greatly reduced- This minimizes the so-called bumping of the register segment usually mounted on the cylinder and register rack on the bedto insure perfect registrationon beginning of the printing operation. The reduction in the'number of gear meshes also makes the press exceptionally smooth running, which characteristic is reflected in a longer useful lifeiof the press.

' It will be noted that the rack 56 through which the bed is driven on a printing stroke is located generally centrally of the bed, whereasthe rack 62 through which the bed isdriven on a reverse stroke is located adjacent the edge of the bed which carries the inker driving rack 23a. This arrangement has been found particularly ad:- v'antageous in that it reduces any tendency which the bed might otherwise have to skew upon the reverse stroke. The relatively heavy load imposed upon movement of the bed in a printing stroke is takenby the generally centrally disposed rack 56. On the reversestroke of the bed the principal load is imposedby the inker, as there is very little resistance to the reverse movement of the bed itself. By positioning the rack 62 adjacent the edge of the bed which carries the rack 23a the force which is consumed mainly in driving the inker on the reverse stroke is applied adjacent the edge of the bed at which such force is transmitted to the inker, thus reducing to a minimum the lateral distance between the points of application of force and hence reducing the tendency of the bed to skew I upon the reverse stroke.

Although I have illustrated and described but a preferred embodiment of the invention, it will be understood that changes in the construction and arrangement disclosed may be made without departing from the spirit of the invention 0 the scope of the appended claims,

I claim: 1. In a press, a frame, a bed reciprocable alon tracks on said frame, reversing shafts journaled in said frame adjacent the ends thereof, a hanger.

depending from said bed having inclined plane bearing surfaces extending laterally therefrom,

and the other of said gears, and a cylinder journaled in .said frame for cooperation with said bed, said cylinder being driven directly from said intermediate shaft.

2. In a press, a frame, a bed reciprocable along tracks on said frame, reversing shafts journaled in said frame adjacent the ends thereof, a hanger depending from said bed having inclined plane bearing surfaces extending laterally therefrom, cranks on said shafts having rollers adapted to engage said surfaces respectively when the bed nears the ends of its stroke, said surfaces and rollers lying in the same plane longitudinally of the press, gears on said shafts, a main drive shaft deriving its power from outside the press having a pinion thereon meshing with one of said gears,

an intermediate shaft having a gear thereon meshing with said pinion and the other of said gears, and a cylinder journaled in said frame for cooperation with said bed, said cylinder being driven directly from said intermediate shaft.

3. In a-press, a frame, four parallel tracks on said frame extending longitudinally thereof and spaced across the Width of the frame, a bed reciprocable along said tracks, the minimum center-to-center distance between adjacent tracks being at least 75% of the maximum center-tocenter distance between adjacent tracks, reversing' shafts journaled in said frame adjacent the ends thereof, a hanger depending from said bed having inclined plane bearing surfaces extending laterally therefrom, cranks on said shafts having rollers adapted to engage said surfaces respectively when the bed nears the ends of its stroke, gears on said shafts, a main drive shaft deriving its power from outside the press having a pinion thereon meshing with one of said gears, an intermediate shaft having a gear thereon meshing with said pinion and the other of said gears, and a cylinder journaled in said frame for cooperation with said bed, said cylinder being driven directly from said intermediate shaft.

4. In a press, a frame, a bed reciprocable along tracks on said frame, reversing shafts journaled in said frame adjacent the ends thereof, a hanger depending from said bed having inclined plane bearing surfaces extending laterally therefrom, cranks on said shafts having rollers adapted to engage said surfaces respectively when the bed nears the ends of its stroke, gears on said shafts, a main drive shaft deriving its power from outside the press having a pinion thereon meshing with one of said gears, an intermediate shaft having a gear-thereon meshing with said pinion and the other of said gears, and a cylinder journaled in said frame for cooperation with said bed, said cylinder being driven directly from said intermediate shaft, all said gears being located outside of said frame.

5. In a press, a bed, an inker, means disposed in the vicinity of the longitudinal center line of the bed for driving the bed upon a printing stroke, means carried by the bed at an edge thereof for driving the inker and means disposed adjacent said inker driving means for driving the bed upon a reverse stroke.

6. In a press, a bed, an inker, means for driving the bed upon a printing stroke, means carried by the bed for driving the inker and means for driving the bed upon a reverse stroke, the means for driving the bed upon a reverse stroke being disposed adjacent the inker driving means and nearer such means than the means for driving the bed upon a printing stroke.

'7. In a press, a bed, an inker, a rack connected with the bed through which the bed is driven upon a printing stroke, a rack connected with the bed through which the bed is driven upon a reverse stroke and means carried by the bed for driving the inker, the second mentioned rack being disposed adjacent the inker driving means and nearer such means than the first mentioned rack.

8. In a press, a bed, an inker, a rack carried by the bed and disposed in the vicinity of the longitudinal center line of the bed through which the bed is driven upon a printing stroke, a second rack carried by the bed at an edge thereof for driving the inker and a third rack carried by the bed and disposed adjacent said edge of the.

bed through which the bed is driven upon a reverse stroke.

SAMUEL A. HUFFMAN.

Images