US1786570A - Machine for transferring designs on to cylindrical surfaces - Google Patents

Description

Dec. 30, 1930. l.. LlNzELL ET AL IMACHINE FOR TRANSFERRING DESIGNS ON T0 CYLINDRICAL SURFACES Filed Sept. 20, 1929 8 Sheets-Sheet l L.. L lNZELL ET AL Dec. 30, 1930.

MACHINE FOR TRANSFERRING DESIGNS ON TO CYLINDRICAL SURFACES Filed Sept. 20, 1929 8 Sheets-Sheet 2 L. LINZELL ET AL 1,786,570

MACHINE FOR TRANSFERRING' DESIGNS ON T0 CYLINDRICAL SURFACES Dec. 30, 1930.

Filed sept. 2o, 1929 8 Sheets-Sheet 3 De@ 30, 1930. 1 LINZELL ET AL 1,786,570.

MACHINE FOR TRANSFERRING DESIGNS ON TO CYLINDRICAL SURFCES Filed Sept. 20, 1929 8 Sheets-Sheet 4 Dec. 30, 1930. L. LINZELL ET AL. 1,786,570

MACHINE FOR TRANSFERRING' DESIGNS ON TO 'CYLINDRICAL SURFACES 8 Sheets-Sheet 5 Filed Sept. 20, 1929 Dec. 30, 1930. L. LIN-ELL ET AL 1,786,570

MACHINE FOR TRANSFERRING DESIGNS ON TO CYLINDRICAL SURFACES Filed sept. 2o, 1929 s sheets-sheet e 8 Sheets-Sheet 7 L. LINZELJ. ET AL Filed sept. 2o,\`129 Dec. 3o, 1930.

MACHINE FOR'TRANSFERRING DESIGNS ON T0 lCYLINDRICAL SURFACES /wW/Z Dec, 30, 193U. l.. LlNzELl. ET AL 786570 MACHINE FOR TRANSFERRING DESIGNS ON TO CYLINDRICAL SURFACES Filed Sept. 20, 1929 8 Sheets-Sheet 8 f 176 175 15.91% .6W 1i- 162/@2179 17,? @i v-ao f SS 1 l lr? rare senr

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LESLIE LINZELL, OF LONDON, AND THOMAS EWART PHYTHIAN, 0F LEEDS, ENGLAND,

ASSIGNORS, BY MESNE SSGNLYENTS, TO LETHORINTEX CORPORATION, .A CORFO- RATION OF DELAJVARE MACHINE FOR TRANSFERRNG DESIGNS 0N TO CYLINDBICAL SURFACES Application lfiled September 20, v1929, Serial No.

Vhis invention relates to machines for transferring or offset printing of designs ou to cylindrical surfaces, wherein the design on a .fiat design-bearing surface, is transferred or offset to a resilient curved member, from which it is transferred to a cylindrical surface or roller to be exactly covered by the design. Such a machine is particularly adapted for transferring` inlr from a printing surface to the surface of a roller which b y subseouent etchinoy can be transfermed into a printing surface to be used for continuous web printing, and the particular type of machine to which the invention relates is that comprising the combination of a fiat surface or ,bed for bearing a design to vbe transferrecha resilient cylindrical or part cylindrical surface operatively related thereto to receive an impression of the design therefrom, driving means for reciprocating one of said surfaces inrelation to the other, a roller for rotatably engaging said cylindrical surface to receive the design therefrom, and means for pro- .ducing a slight predetermined difference in tlieperipheral velocities of the roller and its engaging resilient' surface, whereby the design as transferred to the roller is lengthened or shortened thereon tocause its ends to meet enact-ly. Y

. The invention has 'for oneof its objects to provide an improved and simplified construction of machine of the type described above which shall be more accurate and more convenient to operate than those known heretofore. In such machines trip mechanism is provided for ensuring that the cylindrical surface shall be rotated in only onedirection by the reciprocation of the bed provided with the flat design-bearing surface, and another object ofthe invention is to providean improved construction of such trip mechanism. A further object is to enable the pressure of the roller on the cylindrical surface to be conveniently regulated, and to ensure that the roller shall press uniformly along its length against that surface. A still further object is to mount the platform of the flat design-bear surface in an improved manner in the machine.

accordi-ng toan important featureof the 393,882, and in Great Britain October 24, 1928.

invention, thereis provided a machine ofthe type described wherein the driving means is in the form of a. reversible electric motor, and a reversing switch for reversing the direction of rotation of the lmotor is arranged to be automatically actuated (e. g. by one of the driven surfaces) at the end of the travel of the flat design-bearing surface, `in order to effect simplification of, and increased accuacy of working of the ina-chine, and to enable he total height of the machine to be reduced compared with constructions known heretofore. c y f a e According to another important feature of he invention, there is provided a machineof thHV type described comprising a mutilated geanvrheel serving for driving said cylindrical surface and arranged to be driven bj; Va toothed rack movable to and fro with the bed of said fiat design-bearing surface, and locking means arranged to lock said gearwheel against rotation during the return movement of the rack, in combination with trip mechanism movable with the designl ng bed and arranged (o) to disengage .il locking means at the end of the return movement of the bed, Z2) to bring the gearwheel'into mesh with the rack at or near the commencement of the operative stroke of the bed, and to engage the locking means at the end ofthe operative stroke of the bed. Such trip mechanism occupies only a very small space, comprises parts that are light in ght and is considerably simpler than trip mechanism used heretofore for the same purpose in such machines.

Conveniently, the locking means aforesaid comprises a stop (e. g. a tooth) carried by said gear wheel, a spring-controlled detent movable into and out of locking engagement with said stop, and a catch for holding said detent in its unlocking position, and said tripping mechanism comprises two trip members, one at or towards each end of the design-bearing bed, arranged respectively to co-act one with said catch, and the other with said detent at the two ends of travel of the bed.

According to yet another' important feature of the inventiong there is provided in a machine of the type described a pivoted lever whereon the roller is journalled, and actuating means (e. g. a rotatable cam) arranged to rock the lever to move the roller into and out of contact with the cylindrical design-transferring surface, in combination with a spring (e. g. a stiff spring) so associated with said lever (e. g. ata situation between its ends) that the spring transmits the force of the actuating means tending to press the roller into contact with the said cylindrical design-transferring surface in order to obviate excess pressure between the roller and the blanket of the cylinder coacting therewith.

Preferably, the lever aforesaid in which the roller is journalled comprises two separate lever-arms operatively connected together by said spring.

Conveniently, this spring tends to move the lever-arms angularly relatively to one another, and means is provided for limiting such angular movement.

According to another feature of the invention, the lever aforesaid is combined with indicating means associated with said spring for indicating the pressure of the roller on its co-operating cylindrical surface.

Other features of the invention relating to the said trip mechanism, the mounting of the said roller, the track for the bed of the design-bearing surface, and the angular adjustment of the bed will be described hereinafter and pointed out in the claims.

One embodiment of the invention is diagrammatically illustrated, by way of ei;- ample, in the accompanying drawings, wherein Figure 1, is a side elevation showing one form of machine according to the invention, viewed from the side thereof at which the motor is situated,

1igure 2 is a rear end elevation as viewed from the right hand of Figure 1, and

Figure 3 is a top plan view thereof, with certain parts removed, and Y Figure 4: is a cross-section taken on the line 4-4 in Figure 3;

Figure 5 is a side elevation of part of the machine shown at the right of Figure 2, illustrating cam mechanism, and the mounting of the roller, and

Figure 6 is a detail perspective view of the cam shown in Figure 5, some parts being shown broken away;

Figures 7, 8 and 9 are detail side elevations of parts of the machine shown at the right of Figure 2, illustrating the mutilated gear wheel and trip mechanism, and

Figure 10 is an end elevation partly in vertical cross-section taken on the bent line 10-1() in Figure 7, Figures 5 to 10 being on a scale larger than that of Figures 1 to 4;

Figure 11 is a side elevation on a still ireaevo larger scale showing part of a bearing bracket and its associated pressure-indicating mechanism situated at the left of Figure 2 and carrying the mandrel of the roller, and

Figure 12 is a sectional elevation showing the mounting of the bearing bracket illustrated in Figure 11 and its companion bracket,

Figures 13 and 14 are enlarged detail sections taken on the lines 13-13 and 11i- 14 respectively in Figure 2 showing parts of rocking mechanism illustrated in Figure 2;

Figure 15 is a vertical section through the platform or carriage taken on the line 15-15 in Figure 3, and

Figure 16 is a wiring diagram showing one form of the electrical connections of the motor and switches controlling the latter.

Like reference characters designate like parts throughout the several views.

Referring to Figures 1 to 11, a. main rectangular frame 10 comprises two side- pieces 11, 12 and transverse members 13 connecting the latter together at their lower portions so as to leave the upper part free for a reciprocatory platform or carriage 14 for a flat design-bearing surface. Journalled at or near the middle of the two side-pieces is a main shaft 15 that carries at the middle of the frame a driving gear-wheel 16 meshing with a central toothed rack 36 on the underside of the platform 14, and two large diameter rollers 17, 1S, one at either side of the wheel 16, the two rollers 17, 18 being identically the same diameter. A worm wheel 19 is keyed on one end of the main shaft 15 outside the side-piece 11 of the frame 10 and meshes with a worm 2O on a shaft Q1 that extends lengthwise of the machine and is journalled in bearings on the side-piece 11, a casing QQbeing provided for enclosing this worm gearing.

A reversible electric vmotor 2li of any convenient construction is arranged to drive the worm shaft 21 in any convenient manner, for example as described hereinafter with reference to Figure 16. As illustrated, the motor 24 is mounted on a sill 25 on the sidepiece 11 at one end of the shaft 21, to which it is connected by reduction gearing 26, so that the motor drives the main shaft 15 through double reduction gearing. The other V end of the sha-ft 21 is detachably coupled at 27 to one end of a manually-operable shaft 28 that is journalled at 29 in the side-piece 11 and has its free end 30 squared to receive a handle, so that when the motor is not in operation the main shaft 15 can be rotated by hand for idling the platform or carriage 14 to any desired position along the machine.

A track for the platform 111 is in the form of a double line of rollers arranged in pairs, whereof a large diameter pair 17, 18 is at tyres the middle of the line, the remaining rollers 3l., being ofsmall diameter. These smaller rollers 31, 32 are situated atfeither side of the larger pair towards .the ends of the line and are mounted'on axles 33 journalled in the side-pieces ofthe main frame, two rollers on each axle. rlhe bearings ofk these axles 33 are preferably adjustable in height in the machine in order to take up any wear of the rollers that may occur. rihe platform carries en its undersiee two guieeways 35 or tracks of inverted l..-section, one for Yeach line of rollers, between which is situated the inverted toothed rack 36 meshing ends of the main frame l() may be provided for reversing the motor at the end ofthe forwarder operative travel of the platform, and stopping` it when the platform returns to its normal orrest position at the front end of the machine as shown in Figures l and 3. As compared with the known construction referred toabove, wherein a gear wheel driven by a crankshaft rolls between two toothed racks., one "fixed at the bottom of the main frame, and the other carried by the platform of the flat design-bearing surface, the described electric drive has the advantage that backlash in the'known gearing is 'obviateth and the total height of the machine can be reduced.

As clearly shown in Figures 3 and 4, a bed plate 40 is mounted so asto be adjustable in height on the platform i4 by means of four vertical screw-threaded lifting spindles 4l having squared upper ends. This bed plate 40 carries a design-carrying table 42 which is centrallyT pivote-d in known manner on the bed plate by means of a pivot-pin 43. The upper face of the table 42 is smooth and, when the machine is in use, has a suitable metallic sheet 44 (Figure l5), for example a Zinc plate, carrying the design to be transferred stretched over its smooth top which constitutes a bed for the sheet, holes 143 being formeel inthe table top to aord access to the spindles 41. Any convenient means may be used for stretching the sheet on the table, but preferably so-called 30o parallelmotion grippers 45 known in themselves are used, as illustrated in Figures 3 and l5. VFour such grippers 45 are shown at the front edge Y of the table 42, whilst kthe rear edge of the sheety 44 is held by a channel bar 46 bolted along the rear edge of the table. Means for .turning the table about its pivot 43 will be described hereinafter.

Extending vertically in known manner fron the middle portion of each side-piece the n i frame arepedestals or pillow blocks 5l and as shown in Figures l, 2, aand .7. ln these. pillow blocks is ournalled a shaft carryino, as usual, a cylindrical frame 54 latin g a smooth periphery. il rubber blanket g, as usual, the resilient cylindical surface aforesaid extends any con- 'ent distance round the cylindrical frame 54 and can be stretched over it by any conient or known means. he larger pair of rollers l?, lis preferably situated substantially vertically below the axis of rotation of the cylindrical surface 55, supporting the travelling bed directly beneath the centre ofpressure of the cylinprovidin 0" drical surface thereon, and, as illustrated, the

shaft l5 is vertically below the shaft`53.

The upper ends of the pedestals 5l. 52am extended in the form of, or are otherwise pro il ed with, horizontal arms.v4 57 respecltiyely, in the outer ends of which is `iour- .alled a. rock shaft 58 (Figures l, 2, 5 and that lies parallel with the shaft 53 of the cylinder rllhis rock shaft carries a roller, designated generally (9,. of levers in the form of bearingbraclrets 60, 6l. one on each end of the described hereinafter. rlhis roller 5S) compris s a. mandrel or shaft 62 journalled in the brackets. on which mandrel is secured cylinder or sleeve 33, for enan'lple of copper or brass, for receivthedesign. l A f As shown in Figures 5 and 6, a cam designated generally 64 is keyed on one end of a short axle 65 ournalled in a pedestal 66 on the top of the pillow block V2. il spur gear wheel 67 is keyed on the other end of the same axle 65 and meshes with a mutilated spur gear wheel 68 keyed on the shaft 53 of the blanket cylinder 54. This mutilated gear wheel 68 is arranged to mesh with a toothed rack 69 bolted to the iilatfcrm 14.

A pinion 'l0 is keyed on the mandrel (32 near its end remote from the cam G4 and meshes with an idler 7l loosely mounted on the shaft 53 at the opposite end from the mutilated gear wheel 63. This idler meshes with teeth 72 on the upper edge of a rack bar 2' 3 which, for the purpose described hereinafter, is mounted to move endwise on the platform in any convenient manner, the pitch of the teeth of the tooth-ed rack 73 being less than that of the rack G9.

ln order that the blanket cylinder may rotate always in one direction and yet be driven by the reciprocatory platform 14, the toothed rack 69 is arranged to drive the mutilated gear wheel 68 in only one direction, the arrangement being such that when the' platby means form 14 moves from the front to the rear end of the machine in its operative, i. e. design-transferring, direction, indicated by the arrows 99 at the ends of Figures 1, 8 and 8, the mutilated gear wheel 68 in mesh with its rack 69, and the blanket is rotated into engagement with the design sheet as it passes beneath the cylinder, at peripheral velocity equal to the velocity of the design sheet, whilst when the platform 14 is returning to its front orloading position in the opposite direction the gear wheel 68 is not rotated.

The gear wheel 68 is wider than the rack 69 and is mutilated (see Figures '7' and 19) by having only a portion 74 of its teeth removed along a chord of the wheel at a situation which is opposite to the toothed rack 69 at the ends of the travel of the platform 14. The pinion 67 is substantially as wide as the gear wheel 68, so that thel cam 64 can continue to rotate when the mutilated portion of the gear Wheel 68 is adjacent to the pinion 67; the angular velocity of the cam 64 relative to the blanket cylinder' is fixed, and is preferably half that of the blanket cylinder. Mounted on the side of the gear wheel 68 at its mutilated portion 74 is aplate 75 having at its side a tooth 77 in line with a mutilated tooth of the Wheel and constituting a stop. rit the end of the operative stroke of the platform 14 this stop 77 is held by locking mechanism described hereinafter until the platform has moved to the other end of its travel, during which return movement the rack G9 moves idly under the mutilated gear wheel 68 and the roller 63 remains stationary.

As shown in Figures 2, 7, 8 and 9, this locking mechanism comprises a spring-controlled detent 8O pivoted at 81 on the side-piece 12 of the frame 10 and arranged to engage, in its locking position, with said stop 77 which enters into a. notch 89. in the detent. A spring-loaded catch 83 pivoted at 84, on the side-piece 12 of the frame 10 is arranged to engage the detent 8O in its unlocking position and hold it therein against the action of its spring 85. Tripping mechanism for controlling said detent 80 comprises two trip members 87, 88 at opposite ends of the rack 69; the member 87 is in the form of a springcontrolled lever that is pivoted at 89 on the side of the platform and is arranged to engage said gear wheel stop 77, when the detent 80 .has been disengaged therefrom, at the end of the return stroke of the bed, and to drive the mutilated gear wheel 68 during the first part of the working st-roke of the bed and thereby bring the gear wheel 68 into mesh with the rack 69. The second trip member 88 is operative at the end of the working stroke of the design-bearing bed and is also mounted on the side of the platform and has two operative faces 90, 91; the face 90 is arranged to coact with said catch 83 and release it from the detent 80, and the second face 91 is arranged simultaneously to coact with said stop 77 and position it ready for its engagement by the released detent 80.

The trip member 87 is shown as a doubleended lever, whereof one end is controlled by a spring 92 which tends to rock the second end upwards, The latter end has its lower portion shaped a cani 98 arranged to engage a transverse stud 94 on the detent 80 and thereby release the latter from the gear-wheel stop 7 7, whilst its upper portion has in it a notch 95 into which the said stop 77 can snap when the platform has arrived at the end of its inoperative or return stroke. The second trip member 88, shown as a plate, has its two operative faces 90, 91 formed respectively at its lower and upper edges, the lower face 90 being situated somewhat nearer the detent 8O than is the upper face 91 to allow for the distance through which the platform moves during the release of the detent 8O from the stop 77.

lallien the platform 14 with the rack 69 has completed its operative stroke and is at the rear end of the machine, (i. e. at the righthand end of Figures 1 and 8 and to the left of Figure 7) and the detent 8O is in engagement with the gear-wheel stop 77, the limit switch 87 is actuated and the movement of the platform is reversed; during the return movement of the platform the shaft 53 and the blanket cylinder 54 remain stationary and the tripping mechanism willl occupy the position shown in Figure 7. Near the end of the return stroke the cam 93 on the lever 87 engages a transverse stud 94 on the detent 80, and depresses the latter which is then held in its lower disengaged posit-ion by its catch 83. At this moment the lever 87 snaps into engagement with the gearwheel stop 7 7 the platform having then arrived at the limit of its travel in the direction of its inoperative stroke e. at the front end of the machine) and has operated the limit switch 38, thereby stopping the motor, as described hereinafter. When the motor 24 is started again its direction of rotation is reversed and, when the operative stroke of the platform begins, the lever 87 in engagement with the gear-wheel stop 77 rotates the blanket cylinder in a clockwise direction, as viewed in Figure 7. This continues until the unmutilated teeth of the mutilated gear wheel 68 mesh with the teeth of the rack 69 for driving it, which rack remains in mesh with the gear wheel 68 until the curved face 90 of the plate 88 contacts with a transverse pin 97 on the catch 83 near its upper end and at the same time locates the gear-wheel stop 77 b v means of the face 91 in such a position that the released detent 80 will engage the stop 77 lhen this occurs the platform is at the limit of its travel in the direction of its operative stroke, (i. e. at the rear end of the machine), the reversing switch 37 is operated, the motor 24 is again 1,786,5fro

the trip frane c urn movement of the bed, to f whe-el into mesh with the i keof the bed, and to engage the detent with the Wheel 08 au `the f the operative stroke of "h tripcribec. With machines of the type referred` to known heretofore, the roller 59 isY mounted in an improved manner Which will novf be described. Referring to Figures 5, 11 and 12, the rock shaft 53 has tvfo bushes 100, 101 fast thereon, one at each end, which bushes have each radial abutment 102,104, respectively, each in the form of a perforated lug. rllhe said bearing brackets 60, 61 in which the roller 59 journalled are mounted to rotate 'each on one of these bushes, and have each a lateral abutment 103, 105 each in the form of a lug. These lugs are arranged in pairs 102, 103 and 10e, 105, the lugs of each pair being situatec side-by-side but spaced apart with a stift1 spring 106, 10.7, respectively, between-them. -These springs tend to rock the bearing brackets round the bushes in a direction to press the roller 59 against the blanket cylinder Means in theform of nut-equipped bolts S, 109 ef;- tending each through a perforated lug, and surrounded each by one of the springs, is provided for limiting the angular movement of the brackets G0, 61 about the rock shaft. Split journal blocks 110, 111 for the mandrel 02 are adjustable in known manner by means of screw 161 in the brackets 60, 61, and the roller 59 can be adjusted towards and away from the blanket cylinder 56 by adjusting the journal blocks in the brackets. A lever arm 112 has one end fast ,on one end of the rock shaft 58 and carries atits other sa end an anti-friction roller 113 co-acting` with said cam Gel (Figures 5 and 6), whereof the aeripheral velocity relative to that of tl ola et is fixed, and in he present machine thei perioheral velocities are the same.

1his lever arm 112 is shown distinct from the l' .c nt bush 101, each being keyedV sepato the rock shaft 53, but it may be in- `.5i-al'thereivith if desired. End plates 300 rve to hold the bush 100 and lever 112 on `.e shaft 58. A' rod 114 pivotedto the arm m used heretofore in nnichines 112, and a compression spring 115 surrounding the rod 114 serve, in known manner, for thrusting the arm 112 upwards and holding the roller 113 against the periphery of the cam 64.. This upward movement of the arm 112 is suiiicient to raise the copper sleeve 63 out of cor-tact with the rubber blanket when the roller 113 is engaging certain portions of the cam surface; but when the roller is engagement with elevated portions of the cam surface l'he arm 112 is forced down into a position to throuT the copper sleeve back into engagement with the rubber blanket. This rocking movement of the arm 112, While sufficient to disengage the roller 59 from the blank, is not great enough to disengage the pinion from its 'driving Lgear Wheel 71.

The cam 6d shown in Figure 6 is of a construction kno-Wn in itself and comprises three plates, a central fixed plate 117 and tvvo adjustable side plates 118, 119 which are secured to the central plate by bolts 120, 121 which pass through slots in the side plates and are threaded into the lixed plate. Each plate has a portion of its circumference raised a sulieientheight so that when the anti-friction roller 113 is in engagement with that portionk the copper sleeve 63 of the roller 59 Will be lforced into engagement with the rubber blanket, and the different plates of the camgmay be so adjusted with respect to each other that there Will be a continuous raised portion of the periphery of the cam Which Will be such as to `hold the copper cylinder in contact With the blanket until it has made a complete revolution. Moreover, the two side plates 118, 119

iay be so adjusted with respect to the centre plate as to lower and permit the lifting of the copper sleeve 63 at any desired pointon the rubber blanket.

Any convenient or known means may be provided for rendering the cam 611 and antifriction roller 113 inoperative to move the copper sleeve 63 into engagement with tl e rubber blanket at such times as it is desired to adjust other parts of the machine` l-is illustrated in Figures 2 and 5, the anti-friction rollerv 113 is carried by an eccentric disc 123 having' its pivots journalled in the forked nd of the lever arm 112. One of these pivots carries an adj Listing arm 124ihavinga handle member 125, and the other carries a nut 126 (Figure 1) for lining' the eccentric4 in its position of adjustment in its fork.

It is desirable that the pressure of the roller 59 against the blanket shall not be too heavy nor too light, and according-ly indicating means associated with said springs 106, 107 are provided for indicatingl such pressure. Preferably such indicating means are provided at each end of the roller 59 and are similar to one another, so that a description of one Will sutlice for both.

. As shown in Figures 11' and 12, a lever 127 pivotally mounted at one end on thel lug 103 of the movable bracket 6G, has its other end arranged to actuate, bv means of an adjustable screw 123, a p sure indicator 129 mounted on the same l,M L lt. A link 130 has one end pivoted to this lever 127 at a point between its fulcrum and the Ncrew 123, and its` other end pivoted to the at", 102 on the bush 100. Consequently, waen t' `e spring 106 compressed, due to the rock shaft 53 being rotated, the pre. ,ire gauge 129 will ifu'licate the amount of compression of the blanket by the roller 59 pressed against it. 'Ehe described indicators are preferably used as follows z-iifter setting the roller 59 so that it just contacts with the blanket on the impression cylinder, the dials of the two indieatorswill be set to xero. jressure acting "r move the through the springs 106, 107 w levers 127 and he indicated on the dials so that it can be readily ascertained whether the pressure of the roller 59 on the blanket is uniform along its length, any necessary adjustment being made by sli ing a journablock 11() or 111 in its bracket.

Any convenient means may be provided for producing a slight predetermined difference in peripheral. velocities of the roller 59 andits engagement surface of the blanket whereby the design, transferred to the roller, is lengthened or shortened thereon when necessary to cause it" ends to meet Ll/D exactly. One construction of such means in the form of differential gearing of known design comprises a slide block or roller 132 (Figures 2 and arranged to move backwards and forwards in a slideway 133 and shift a short rack 332 meshing with a gear 334 which is arranged to shift the toothed rack 73 meshing with the idler 71. The slideway 133 is pivoted at its front end on the main frame and can be rocked at its rear end by means of rocking mechanism designated generally 134. In the present construction this rocking mechanism comprises amanuallyoperable screw-threaded spindle 135 mounted in a block 235 (Figure 14) on the sidepiece 11 of the main frame. A plate 336 bolted to the slideway 133 has a circular recess for receiving a ring 333 fast on a spindle 339 on a nut member 136 on the spindle so that by turning a graduated handle memlrcr 340 on the spindle the slideway can be moved angularly about its pivot towards and away from the side-member 11. Such angular movement that may be required at any time is only small, and the consequential angular movement of the spindle 135 in relation to the side-piece 11 is provided for by the described swivelling construction. rlhe operation of the gearing controlled by this slideway is the same as in known machines of the type referred to above and therefore need not be described in detail. The present construction avoids backlash which is present when worm gearing is employed for rocking the slideways as in the. known construction referred to.

ln order to correct relative mis-match of the corresponding points in the ends of the design when transferred from the design sheet to vthe copper cylinder, the table 42 that carries the flat design-bearing surface is mounted on the platform 14 to swivel in its own plane about a central axis of rotation at 43, and ad'usting means are provided for angularly adjusting the table. 1n the improved construction the adjusting means comprises two oppositely-acting screws 140, 141 (Figures 3 and 4) that are mounted on one side of the platform 14 and bear against the table 42 at opposite sides of the transverse vertical plane containing the pivot 43 and, when operated, tend to rotate the table in opposite directions and normally serve each as a stop to hold the table against rotation by the other. This arrangement avoids the use of worm gearing for adjusting the bed of the sheet and consequently obviates the defects due to backlash in such gearing. Preferably the screws are associated with means, such as graduations on the screw-heads, movable in relation to marks on the platform for indicating the angular position in which the bed is set. By means of these screws and graduated scales associated therewith the bed may be rotated above its pivot, in one direction or the other, the exact amount that the ends of the design are found to be mismatched laterally.

As shown in Figure 1, a structure 350 constituting a platform may be mounted on the frame 10 at its rear end for facilitating an operator having access to the upper parts of the machine.

The electrical equipment of the machine will now be described with reference to the diagram Figure 16 which shows the shuntwound direct-current motor 24 comprising an armature 150 and field winding 151, two double- pole reversing contactors 152, 153 which may be interlocked, a single-pole starting-resistance contactor 154, a main double-pole circuit-breaker 155 and double-pole fuses 156, the mechanically-operated limit or reversing switch 37 (Figure 9), the mechanically-operated limit or stop switch 38 (Figure 8), and also a forward switch 159, reverse switch 160 and stop switch 161, each operable manually. The switches 37 and 33 are on the machine, while the switches 159, 160 and 161 may be mounted elsewhere, e. g. on a panel on the wall of the machine room.

The forward contacter 152 has three movable Contact arms 162, 163, 164 which, when its winding 165 is energized, contact respectively with the fixed contact- pieces 166, 167 and three contact-pieces 163, 169, 170.

Similarly, the reverse contactor 153 has three movable contact arms 172 173, 174" which, 'when its winding 175 is energized, Contact respectively kwith the fixed contactpieces '176, 177 and three contact- pieces 178, 179 and 180.. Y

Then these contactors 152,153 are de-energized the arms 162, 172 rest each against a v contact-piece inthe form of a back stop 181, 182 respectively, between which 1s connected 'forward end of its travel and holds it open.

The lreversing switch 37, which may be a quick vmalie-and-break single-pole changeover switch., and has a handle 187 (Figure 9) and comprises two pairs of contact- pieces 188, 189 and 190, 191, and a switch blade 192 fio-operating therewith.

The manually-operated switches 159, 160, 161 are preferably each of the spring-controlied plunger or push-button type, and may Y have each two fixed contact- pieces 193, 194 and 195, 196 and 197, 198 respectively, the forward and reverse7 switches 159 and being normally open and the stop n switch 161 normally closed as shown.

The contractors are connected in circuit as g. the w'- pole) isconnectedby a. lead 200 to the contacts 167 177, and the other pole is connected by a lead 201 to the contact 185 and to one end of the start-ing resistance 186, whereof the other end is connected to the 184 and to the contacts 166, 176. The arms 163, 172 are connected together and to one brush of the motor, the other brush being connected to the arms 162 and 173. A shuntfield-discharge resistance 203 is connected in llei with the field-winding 151 across the ds 201. 202. `One end of the coil 183 is connected to the contact-piece 176 and its other end is connected to the contacts and 180.

The forward switch 159, the reverse switch 160 and the stop switch 161 are connected in circuit as follows Contact 198 is connected to the lead 200, and a wire connects the contacts 197, 196, 194E with the contact 169 of cont-actor 152. The Contact 193 is connected to the Contact 168 and to one end of the coil 165, whereof the other end is connected to the contact 188 of the reversing limit switch The two contacts 190, 191 of the latter connected respectivelyY with the contacts 96 and 195 of the reverse switch 160, the wo contacts 196 197 being electrically` conrilhe Contact 195 of this I tot, ,1i together.

switch 160 is connected to the contact 178 and to one end of the coil 175, whereof the other end is connected to the movable arm of the stop limit switch 38, whose fixed contact-piece 20st is connected to the contact 189 which is connected to the contact 185. A

Assuming that the platform 14 is in its forward or norniai end position of loading and that the swncnes and connectors are in the position shown in if'fig'ure 16, if the forward switch 159 closed by hand to traverse the platform, the coil 165 is energized, the contacter 152 is operated amthe motor 21 is connected avcroA Vr1`he startinglesistanccc .ctor 15dv then'operates and cuts t ie starting resistance 186 ont circuit,v so that the motor rotates in the direction to a f rd drive to the platform 111. the piatiom arrives at the rear end of 20 (Figure 9) adjustably side of the platform operates mounted on the i 4mit 'witch 37 and throws it 3, however, is energized L driven in the opposite *e drive will continue until the piatforin arrives in its forward position where an adjustabie stop 210 (Figure 8)'Kon the side of the platform will open the stop limit switch`38. T ie coil is then dcenergized l the reverse contacter 153 rctnrns toits normal position as shown in Fignre 16, in which. position the resistance 283 is connected in series with the armature 150 for the purpose of causing it to stop rapidly and prevent overrnnning. When the motor was reversed and the platform commenced to return toits front position the 4spring 209 of the reversing limit switch 37 returned. the latter into its normal position, as shown in Figure 16.

1f when the motor isrunning it is desired to stop the platform 14 at any time, it is only necessary to depress the manual stop switch 161. rhe direction of movement of the platform after this stop switch has been released will depend on whether the forward7 switch 159 or the` reverse switch 160 is operated, and whether coily 165 or 175 isy operated and the gir those of the saine type referred to proposed li retofore.

Various modifications may be made in the Y tails of construction described above without.V departing froinrthe- Vi deiiied.V by theclaims. Y f

le claim 1. An offset printing actor described, comprising in combination a reciprocatory bed having fiat surface for bearing a design to be transferred, a toothed rack movable with and extending in the direction of movement of said bed, a resilient cj,flindricall y curve-d surface operatively related to said flat surface to receive an im* pression of the design therefrom, a mutilated gear wheel arranged to mesh with said rack and drive said curved surface, driving means for reciprocating said bed and said rack, a roller for rotatably engaging said curved surface to receive the d ysign there from, means Yfor producing?` a slight prede'- termined difference in the peripheral velocities of said roller and its engaging Vresilient surface. lockingv means arranged to loclr said gear wheel against ro yation during the rf turn movement of the rack, and trip mechanism that is movable with said bedfwhich locking means comprises a stop carried by said gear wheel. a spring-controller detent that is carried by said bed and is movable into and out of locking engagement with said stop, and a tixedly pivoted catch for holding said detent .in its iinlockin position, and which trip mechanism comprises two trip members, one at or towards each end of the bed, arranged respectively7 to coact one with said catch to release it from said detent, and the other with said detent to disengage it from said stop and engage itwith said catch, at the two ends of travel. of the bed.

2. An offset printing machine as set forth in claim 1, wherein the trip member operative at the end of the return stroke of the bed is in the form of a spring-controlled lever that is pivoted on the frame of the bed and is arranged to engage said gear wheel stop, when the detent has been disengaged therefrom, at the end of the return stroke of the bed, and to drive the gear wheel during the first part of the working stroke of the bedY and thereby bring the gear wheel into mesh with said rack.

3. An offset printing machine as set forth in claim 1, wherein the trip member operative at the end of the working strokeI of the bed has two operative faces, whereof one is arranged to coact with said catch and release it from said detent, and the second face is arranged simultaneously to coact with said stop and position it ready for its engagement by the released detent.

4. In Yan offset printingmachine of the character described, the combination of a reciprocatoiy ybed having a flat surface for machine of the charbearing a design to be transferred, a resilient cylindrieally cr` 'ved surface operatively related thereto te receive an impression of the n therefrom, driving means f r reeiprod curved surface te receive the design "om, means for producing a slight prem ied difference inV the peripheral veof said relier and itsrengaging resilsurface, a pivoted lever carrying said amended to move it into and out v i said lever and actuating means rra d te coact with said spring and tiieiebv the lever and press the roller I to contact with said curved surface.

'is an offset printing machine of the described, the combination of a v bed having` flat surface for infn to be transferred, a resilient niv curved surface operatively reo to receive an impression of the from, driving means for reciproi l bed, a roller for rotatably engaging said curved surface to receive the design n' cans for producing a slight prelterence in the peripheral veroller and its engaging resilieci'ies; i ient suiiace. a pivoted lever comprising two mite lever arms, a spring operatively l arms. which lever car ies said .d to move it into and out claim 5, wherein. said spring' tends to more said lever arms angulaily apart, and means is provided for limiting such angular nieve nient.

7. In an offset printing machine of the character described, the combination of a reciprocatoiy bed having a flat surface for bearing a design to be transferred, a resilient cylindricallycurved surface operatively related tlicreto to receive an impression of the design therefrom, driving means for reciprocating said bed, a roller for rotatably engagg ing said curved surface to receive therdesign 'herefroin, means for producing a slight predetermined dilference in the peripheral velocities of said roller and its engaging resilient surface, a pivoted lever carrying said roller and arranged. to move it into and out of contact with said curved surface, a spring associated with said lever and actuating means arranged to coact with said spring and thereby rock the lever and press the roller into contact with said curved surface, and indicating means arranged to indicate the pressure of the roller on said curved surface.

S. In a machine of the character described, a rotary cylindrical desigintransferring surface, two brackets mounted to rock about an axis parallel to the axis of rotation of said surface, a roller journalled in said brackets,

id bed, a roller for rotatably engig-Y id curved surface, a spring a lever arm operatively connected to said brackets, and actuating means arranged to rock said lever arm and thereby rotate said brackets and press the rollers against said surface, in combination with pressure-indicating means at each end of said roller, and means for adjusting'the pressure at one end of the roller against said surface independently of the other end.

9. In a machine of the character described, a rotary cylindrical design-transferring surface, a rock-shaft journalled parallel with the axis of rotation thereof, two bushes fast on said shaft, one at each end and having each a radial abutment, two bearing brackets rotatable each about a said bush and having each an abutment associated each with a said radial abutment to form a pair thereof lying in a plane transverse to the shaft, two compression springs arranged each between the abutments of a pair, means for limiting the movement apart of the abutments of each pair, a roller ournalled in said brackets, and a lever arm fast on said shaft for rocking the latter to move said roller towards and away from the cylindrical design-transferring surface.

10. An offset printing machine of the character described, comprising in combination a frame having a track extending along the same, a platform which is movable to and fro along said track and has a toothed rack, a driving shaft whereof the axis of rotation is fixed in relation to said frame, a gear wheel fixed on said driving shaft and meshingwith said toothed rack, a flat surface for bearing a design to be transferred, carried by said platform, a resilient cylindrically curved surface operatively related to said flat surface to receive an impression of the design therefrom, driving means comprising a reversible electric motor for reciprocating said platform, a reversing switch for reversing the direction of rotation of the motor arranged to be automatically actuated by the platform at one end of the travel thereof, a roller for rotatably engaging said curved surface to receive the design therefrom, and means for producing a slight predetermined difference in the peripheral velocities of said roller and its engaging resilient surface.

1l. An offset printing machine as set forth in claim 10, wherein said track comprises a plurality of rollers arranged in a line, the axes of rotation of which rollers remain stationary with relation to the frame of the machine during the travel of said platform.

12. An offset printing machine as set forth in claim 10, wherein said track comprises a plurality of rollers arranged in a line, the axes of rotation of which rollers remain stationary with relation to the frame of the machine during the travel of said platform, a roller at the middle of said line being of substantially larger diameter than that of the other rollers situated at either side therein claim 10, wherein said track comprises ar plurality of pairs of rollers arranged in a line, the axes of rotation of which rollers remain stationary with relation to the frame of the machine during the reciprocation of said platform, a pair of rollers at the middle of said line being fast on said driving shaft, one at each side of the said gear wheel on the latter, and being situated substantially vertically below the axis of rotation of said curved surface.

14e. An offset printing machine as set forth in claim 10, wherein said track comprises a plurality of pairs of rollers arranged in a line, the axes of rotation of which rollers remain stationary with relation to the frame of the machine during the reciprocation of said platform, a pair of rollers at the middle of said line being fast on said driving shaft, one at each side of the said gear wheel of the latter, which middle pair of rollers is of larger dia-meter than the diameter of the other rollers situated at either side thereof towards the ends 0f the line.

In testimonyv whereof we have signed our names to this specification.

LESLIE LIN ZELL. THOMAS EVART PHYTHIAN.

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