US2026025A

US2026025A - Sectional roll duplicator

Info

Publication number: US2026025A
Application number: US584080A
Authority: US
Inventors: James K Duncan; Dean H Whitehead; Joseph M Cheney
Original assignee: Ditto Inc
Current assignee: Ditto Inc
Priority date: 1931-12-31
Filing date: 1931-12-31
Publication date: 1935-12-31
Anticipated expiration: 1952-12-31

Description

J. K. DUNCAN ET AL 2,026,025

SECTIONAL ROLL DUPLICATOR Dec. 31, 1935.

Filed Dec. 31, 1931 6 Sheets-Sheet 1 j, 176 lnUer-ns: James K. Duncan. Dean H. whifehead.

Joseph JU. Cheney De 31, 1935- J. K. DUNCAN Er AL Y SECTIONAL ROLL DUPLICTOR Filed Deo. 3l, 1931 6 Sheets-Sheet 2 ITK/67115715: i

Jmes K- Duncan Jseph JZ. Cheney @yy/ 4% s Dec. 31, 1935. J, K DUNCAN E1- AL 2,026,025

sEcTIoNAL ROLL DUPLICATOR Filed Dec 51, 1931. 6 She'ets-Sheet 5 H Duncan y Hwhifehad t() +411) "Joseph JTZ. Cheney Dec. S, 1935. ll K, DUNCAN ET AL 2,026,025

'SECTIONAL ROLL DUPLICATOR Filed Dec. 31,'1931 6 Sheets-Sheet 4 f HHH Nfl mln' Inverwj 15 Jc-lme 'C Duncan.

Dean H whiehead. seph U71. Cheney.

Dec- 31, 1935- J. K. DUNCAN ET AL 2,026,025

SECTIONAL ROLL DUPLICATOR Filed Deo. 31. 1931 6 Sheets-Sheet 5 Dec. 31, 1935. J K DUNCAN Er AL 2,026,025

SECTIONAL ROLL DUPLIICATOR Filed Deo. 51, 1931 e sheets-sheet e :F51 ITLUGTIj-'r: Jlme K Duncan. Dean H Whitehead @Selah Cheney- Patented Dec. 3l,A 1935 UNITED STATES PATENT SECTIONAL ROLL DUPLICATOR Application December 31, 1931, Serial No. 584,080

36 Claims.

The invention relates to duplicating machines and particularly to duplicators operating on the hectcgraph principle.

The above type of duplicator is characterized by a flat platen supporting a gelatin band providing the duplicating surface on which master sheets are impressed and from which copies to the desired number are taken. Heretofore the gelatin band has been wound upon spindles journailed in the frame and located adjacent the respective ends of the machine and in order to secure a clean duplicating surface the used portion of the band is wound on one spindle, unwinding the required length of unused band from 'the other spindle. After a number of such winding operations 'the gelatin roll heretofore used would be exhausted making it necessary to replace the same with an unused roll. These replacements interrupted the operation of the machine and such interruptions in duplicating work are objectionable since they reduce the quantity cf work turned out by the operator and add to the overhead cost or" the machine.

An object of the invention is to provide hectograph machines with a relatively long duplicating band which will be wound upon specially constructed drums mounted on spindles and wherein by reason of its length a portion of the band will always be in good condition and ready for use. The provision of a long band eliminates frequent interruptions and only requires occasional rewinding from the forward to the rearward drum.

In order to secure better registration of the printed matter on the duplicated copies it is necessary to maintain the duplicating band in stretched condition on the flat platen. The use of the long band increased the number of convolutions on the roll and it was accordingly found impractical to stretch the supported portion by rotation of the spindles as the excessive number of convolutions resulted in the continual slippage of one on the other.

The invention provides a novel arrangement of parts for snubbing opposed portions of the band at points intermediate the ends of the platen and the spindles for maintaining the length of band on the platen in a stretched condition and which can be readily released to permit the band to be wound. The mechanism is located under the platen out of the way of the operator and serves to relieve the strain which would otherwise be placed on the spindles.

A further object is to provide means for holding portions of the band for maintaining the (Cl. i-133) same stretched on the platen, which will distribute a slight pressureover a wide area at opposed points so as not to injure the delicate gelatnized surface.

A further object of the invention is to provide 5 a novel form of straightening roller which will contact the under surface of the band immediately in advance of the winding drum and automatically function to align the band with the drum. As a result the convolutions of the roll 1o are maintained in vertical alignment preventing damage to the edges of the band.

A further object is to provide an aligning roller having formed on its surface right and left hand threads terminating centrally of the roller for l5 contacting the under surface of the duplicating band whereby the band is maintained in position centrally of the roller.

A further'object is the provision of an improved form of moistening apparatus for keeping the gelatin surface and also the underside of the band in a moistened condition. Better impressions are secured when the gelatin is soft and pliable and by applying Water to the backing' of the band the duplicating surface is kept in condition during the time the same is rolled on the drums.

Another object is the provision of a motor operated drive embodying a clutch to permit selective rotation of the spindles for-winding the gelatin v band. Associated with the motor is a novel form of control means which will operate in sequence to release the snubbing member engaging the band, causing a closing of the motor circuit, and then subsequent to these operations will actuate the clutch to establish a connection between the motor and the desired spindle. A feature of the present invention in connection with the above mechanism is the provision of an electric switch wherein the motor circuit will be closed before an operative drive has been established between the motor and the selected spindle and which will break the motor circuit in advance of the disconnection of the drive.

With these and various other objects in View, the invention may consist of certain novel features of construction and operation as will be more fully described and particularly pointed out in the specication, drawings and claims appended hereto.

In the drawings which illustrate an embodiment of the device and wherein like reference characters are used to designate like parts- Fgure l is an elevational View of the complete duplicator constructed in accordance with the present invention and employing a relatively long duplicating band;

Figure 2 is a fragmentary, vertical, sectional view taken longitudinally of the machine and showing the internal structure for snubbing, moistening and winding the duplicating band;

Figure 3 is a horizontal sectional view taken substantially on the plane indicated by the line 3 3 of Figure 2;

Figure 4 is a transverse vertical sectional view taken substantially on the plane indicated by the line 4-4 of Figure 2; A

Figure 5 is a fragmentary sectional view taken on line 5-5 of Figure 3 and showing in detail the clutch mechanism;

Figure 6 is a View taken substantially on line 6 6 of Figure 3 and showing in detail the construction of the electric switch, the wiring being shown diagrammatically; A

Figure 7 is a detail View showing a modied form of straightening roller;

Figure 8 is a fragmentary elevational View showing a modified construction of brake shoes and operating means therefor;

Figure 9 is a horizontal sectional view taken on line 9 9 of Figure 8;

, Figure 10 is a Vertical sectional View taken on line lil-IU of Figure 8;

Figure 11 is a plan View showing one of the drums equipped with switch actuating means;

Figure 12 is an end view showing the association of the parts immediately before the snap switch is actuated to break the motor circuit;

Figure 13 is an end view showing the association of the parts immediately before the snap switch is actuated to close the circuit;

Figure 14 is a perspective View showing the construction of the diagonal rib;

Figure 15 is an end view showing the position the switch actuating means and snap switch assume during normal operation; and

Figure 16 is a diagrammatic showing of the electrical circuit for the mechanism.

The duplicator and the mechanism for suitably supporting the long gelatin band are supported within a frame consisting of a skeleton frame work braced by transverse and longitudinal members and enclosed by sideA and end members suitably secured to the frame work. Upon each side of the machine is provided a door so as to permit access to the interior for adjusting or replacing any of the parts.

The skeleton frame work consists essentially of four corner supports I, I I, I2 and I3, Figure 3, being provided with rubber feet I4 connected and braced by upper andv lower transverse angle members I5 and I6, respectively, and upper and lower longitudinal angle members I'I and IB, respectively. For enclosing the framework and shielding from view the mechanism supported thereby the corner supports I0 and I I have suitably secured thereto an end plate 20 which extends from slightly above the top of the supports to a point somewhat above the rubber feet I4, as shown in Figure 1. In a similar manner the corner supports I2 and I3 suitably position the end plate 2| which, however, in this instance is directed inwardly at 22 and then downwardly, being secured at its lower end to a transverse angle member I6. Positioning of the end plate in this manner provides sufficient leg room for the operator. For completing the enclosure for the framework the supports have secured thereto longitudinally extending

bottom side plates

23 and 24, being located on the respective sides of the structure and top side plates 25 and 2S. The bottom side plates terminate at the longitudinal angle member I'I which support hinges 2'! for securing the doors 28 to the framework. The doors extend from the angle members to longi- 5 tudinal metal strips 2,9 and from the corner posts Il), I2 and II, I3, respectively. This provides a door in each side of the enclosure of the framework, being pivoted at their lower ends to the framework and provided at their upper ends with 10 a handle Sii adapted to engage the inner surface of the strips 29 for maintaining the doors in closed position. By reference to Figure 1 it will be noted that the

top side plates

25 and 26 extend beyond the corner posts l2 and ISand also 15 that the plate 25 is provided with a bent portion 3|, Figure 4, forming a part of the top plate for the framework. Longitudinal beams 32 and 33 extend from the end plate 2D to the end of the

top sidel plates

25 and 25 and are connected respectively to the end plate 20 and an end plate 36, in turn suitably connected to and joining the ends of the

top side members

25 and 25. The longitudinal beams serve to complete the top plate by having suitably secured thereto the

plate

35, 25 which extends the length of the beams.

The frame constructed and enclosed as above described forms a support for a flat platen and a reciprocating carriage comprising a duplicator. For aligning the carriage with its bed plate the 30 side plate providessupporting arms 25 supporting the guide rod 3l on which the carriage extension 38 is adapted to have reciprocating movements. 'I'he carriage designated in its entirety by 4B and including a paper tray @I for holding 35 the sheets to be duplicated .and an actuating handle 42, by means of which the impression roller is raised and lowered with respect to the duplicating surface, is suitably secured to the extension 38 and provides depending studs 43 40 which engage the marginal edges of the bed plate lili for maintaining the carriage and its impression roller in spaced relation with the bed plate. Mounted on the bed plate is a iiat platen 45 which has supported thereon the gelatin band i6 45 providing the duplicating surface and over which the impression roller and carriage have reciprocating movement due to the travel of the carriage. A forward stop 41 and an adjustable rear stop 48 serve to limit the travel of the carriage 50 in its forward and rearward directions.

The present invention particularly relates to the provision of a relatively long duplicating band wound at each end on suitable drums journalled in the frame. The construction of the drums and 55 their journalling means is more particularly shown in VFigures 2 and 4 and includes longitudinally extending supports 50 and 5I secured respectively to corner supports Iii, I2 and II, I3, and having suitably secured theretoin spaced 60

relation bearings

52 and 53. The bearings 52 are positioned in alignment with each other and serve to rotatably mount the spindle 54, having non-rotatably mounted thereon in spaced relation the discs 55 and adjacent the right hand 65 disc a pulley wheel 56. The discs form end members supporting the drum 51 on the spindle, upon which is suitably wound one end of the gelatin band 36. Y

In a similar manner the aligned bearings 53 70 rotatably mount the spindle 58 having non-rotatably mounted thereon in spaced relation end discs 6@ for supporting the drum 6I and adjacent the right hand disc a pulley wheel 62. 1t will, of course, be understood that the drum 6I has 76 Wound thereon the other end of the duplicating band.

The provision of drums of fairly large diameter for supporting the gelatin roll, as the duplicating band is called when wound thereon, gives greater rigidity to the roll and permits a substantial number of convolutions to be wound thereon before the increase in the diameter of the roll is material. The drum construction is particularly adapted to the present invention since, by reason of the increased length in the duplicating band, the rolls are of increased size and are also of substantially greater weight than the rolls heretofore used.

In order to secure a better understanding of the present invention it is desirable to trace the course of the duplicating band from the printing bed to the drums on which it is wound as described. As shown in Figure 2 the band extends over the left end olf the printing bed and passes overan end roller 63 journalled in brackets 65.. and then travels toward the right passing over a snubbing roller 65 suitably mounted on shaft 65. The band contacts the greater portion of the roller and travels again toward the left, passing over an aligning roller 61 having its shaft 63 journalled in brackets 69, secured to the

side plates

25 and 26, respectively. From the aligning roller the band extends to and is wound upon the drum 6I I'he roller 61 is for the purpose of maintaining the band centrally of the roller during the time the band passes over the roher when being wound upon drum G l. For the purpose the surface of the aligning roller is formed with right and left hand threads 1I beginning at the respective ends of the roller and terminating centrally of the roller so that the surface is provided equally with the various threads. As the backing of the duplicating band has contacting engagement with the surface of the roller it will be seen that the right hand threads engage the right half of the band, functioning to direct this portion toward the center of the roll and in the same manner the left hand threads engaging the leftportion of the band direct that portion toward the center of the roller. When the band is centered on the roller the forces are balanced and the band is held in alignment with drum Si so that during the winding operation the convolutions wound thereon are also in alignment. Should the band for any reason be positioned on roller 61 so that a greater portion of its surface was in engagement with either the right or left hand threads the tendency of the threads would be to direct the band to the center oi the roller and this Would be accomplished until the forces become balanced as described.

In Figure '7 a somewhat modified arrangement of aligning means is disclosed wherein the roller 12 is formed with tapered portions, tapering from the center of the roller at 13 to the respective ends. For maintaining the duplicating band centrally of the roller when having this formation each tapered portion must have contacting engagement with substantially half of the Width of the band. The tendency of the portions to direct their half of the band toward the center is therefore balanced and the band is held in alignment with the winding drum. In operation either form of aligning roller functions automatically to hold the duplicating band having engagement therewith in a substantially central position of the roller and the structure results in accurate aligning and positioning of the band and its convolutions on the winding drum.

The duplicating band passes from the right end of the printing bed over an end roller 14 rotatably mounted in arms 15 pivotally mounted at 16 in the beams 32 and 33, respectively, and being provided at their free end with an in- Wardly direction portion 11. From the end roller the band travels to the left, engaging the snubbing roller 18, mounted on shaft 19, and then to the drum 51 on which the band is wound. As the direction of the band during operation of the machine is from drum 51 over 'the printing bed toward the left and then to the winding drum 6 i, it will be seen that an aligning roller for the right hand portion of the band is not required.

Positioned between and having connection with the

side plates

25 and 26 are two pair of angle supports, namely, 8i) and 8l, the former serving to slidably position within the frame a tray 82 and the latter 'a tray 83. Secured to the right hand end of each tray, Figure 3, is a facing plate 84 provided with knobs 85s, which permits the tray to be withdrawn in that direction from the frame so that it can be filled with water from time to time. The tray 32 has rotatably mounted therein a moistening roller 86 for contacting, by reason of the position of the' tray, the canvas backing of the duplicating band 4S. With the tray supplied with water the roller 855 will apply to the backing sufficient moisture to maintain the backing in a damp condition, and since the gelatin surface of each convolution of the roll has contact with the backing of the adjacent convolution, it will be seen that the gelatin surface will also be maintained in a moist condition. This serves to keep the gelatin soft and pliable and to prevent the same from drying out during the time it is wound on the rolls. As it is desirable to prevent rotation of roller 86 in a reverse direction there is provided the ratchet 81 and pawl 88 which can be thrown out of engagement therewith, when it is desired to discontinue the locking of the roller. Tray 33 also has rotatably mounted therein a moistening roller Q for engaging in this instance the gelatin surface of the duplicating band and-in addition provides a support 9i for a pair of wiping members S52, preferably formed of strips of rubber bent upon themselves with the loop contacting the gelatin. The roller 90 applies a thin film of moisture to the duplicating surface in advance of the positioning of the same on the printing bed and in order to prevent the application of too much moisture, which would smear the master sheet and copies the strips 92 are positioned in advance of the roller. The wiping action which they have with the gelatin surface removes substantially all the moisture and returns it to the tray.

For duplicating machine work it is essential that the portion of the band on the printing bed be maintained in a stretched or taut condition in order to secure registration on the copies. As the present device makes use of a relatively long duplicating band, which results in a larger number of convolutions on the rolls than was heretofore required, it is accordingly impractical to stretch the band on the printing bed and maintain thgame in that condition merely by rotation of the drums. To secure the above condition with respect to the band and in order to relieve the strain which would otherwise be placed on the drums the p-resent invention provides snubbing means operating to grip portions of the band in advance of each drum to holdv the band in stretched condition on the platenuntil released. For the purpose there is associated `with each of the rollers 6'5 and 18 a brake shoe 93 consisting of a length of metal having an arcuate shape transversely thereof and being adapted to contact that portion of the band positioned between the rollers and shoe. The brake shoes are connected and held in spaced relation by end plates 94, Figure 4, suitably secured to depending supports 95 in turn bolted to a depending leg of beams 32 and 33.

The

shafts

66 and 19 of the snubbing rollers are each journalled in end bearings 96 mounted in and having sliding movement in their respective slots 91 provided in the depending supporting plates 95. The construction thus mounts the snubbing rollers for movement toward and away from their respective brake shoes and to operate the rollers simultaneously there is secured to the ends of shaft 66 links 98 pivotally connected to the centers of levers |00. The ends of shaft 19 are connected by links l0! and coil spring |02 to the lower end of levers |00. By rotation of levers |00 in a clockwise direction it will be seen that the links will function to reciprocate the respective shafts and thus the

rollers

65 and 18 in a direction toward the brake shoes and rotation in a counter-clockwise direction will cause movement of the rollers away from the brake shoes. The above actuation of the snubbing rollers is accomplished by the operator through movement of the operating hand |03 suitably secured to shaft |04, journalled at its ends in bearings |05, suitably secured to the side plates of the frame. Non-rotatably secured to shaft |04 at points in substantial alignment with the ends of the snubbing rollers are arms |06 pivotally secured to links |01 in turn secured to the upper ends of the levers |00, respectively.

As the end roller 14 is journalled in pivoted arms 15 it has movement vertically with respect to the printing bed. This construction is provided since it is desirable, especially when the duplicating band is being rewcund on drum 51, to lift the band from contact with the wiping members 92 and the moistening roller 90. Necessary actuation is imparted to the arms for the purpose by rotation of levers |08 suitably mounted in spaced relation on the shaft |09 journalled in bearings 18, through engagement of the studs projecting from the upper end of levers |08 with the portion 11 formed on the arms. Rotation is simultaneously imparted to the levers through pivotal connection therewith of links ||2 pivotally secured at their other end to depending arms ||3 provided on shaft |34. It will be understood from the above structure that rotation of shaft |04 by handle |43 in either direction will function to break the toggle 'connection between arms |05 and their connected links |01 to release the snubbing action of the

rollers

65 and 18. In addition to the above actuation of handle |03 in a direction toward the right will also rotate levers |08, causing a camming engagement between studs and the portion 11, to rock the arm 15 upwardly, lifting the band from contact with the moistening apparatus supported by tray 83. When the handle is in a vertical position or is moved toward the left no actuation is imparted to the arms 15.

For rotating the drums for winding the duplicating band an electric motor H5 secured by strap ||6 to the end plate 34 and having its rotor shaft ||1 suitably connected to speed reducing mechanism |13, also secured to the end plate, is provided. Member |19 connects the speed reducing means with shaft |20 journalled in bearings 2| and having loosely mounted thereon in spaced relation the pulleys |22 and |23. Suitably keyed on shaft |20 intermediate the pulleys but having reciprocation thereon is a clutch member |24, Figure 5, having clutch faces 5 on either side thereof adapted to engage co-operating clutch faces on the pulleys |22 and |23, respectively. Engaging the clutch member is a ring |26 having diametrically projecting pins |21 fitting in openings formed in the yoke |28. l0 Through the pivot pin |30 supported at one end in the top portion 3| and at its lower end in the transverse support |32 the yoke is pivotally mounted adjacent the clutch member and intermediate member and shaft |04. An upper pro- 15 jecting arm |33, integral with the yoke, is provided with a depending stud |34 having location within the spiral groove |35 formed in the spiral |36 noni-rotatably secured to shaft |04. Rotation of the shaft through actuation of handle 20 |03 will rotate the spindle, causing lateral displacement of the arm |33 which accordingly resuits in pivotal movement of the yoke on its pivot pin |30. The ring |26 having operative connection with the yoke is accordingly reciprocated on 25 shaft |20, imparting like movement to the clutch member to operatively connect the member with either the pulley |22 or pulley |23.

The above structure providesI a motor operated drive and clutch means therefor so that 30 actuation of handle |03 will serve to operatively `connect the drive to either pulley, as desired, which, through the driving belts |31 and |38 will rotate the pulley wheels and their corresponding drums 51 and 8|. It will be noted that belt |38 35 also engages a pulley |40 suitably mounted on shaft 68 associated with the aligning rollers.

In order to provide a single control means so that the operator through actuation of 'one member can control the movement of the snubbing 40 rollers and the clutch member and also operate the electric motor the present invention positions an electric switch on shaft |04 housed within casing |4| suitably supported from end plate 25 by means of support |42, Figure 6. Essentially 45 the switch consists of an insulating plate |43 positioning in spaced relation contacts |44 suitably connected to a common conductor |45 forming one side of the power supply line. The other terminal of the power supply line |46 is 'con- 50 nected directly to the motor ||5 while the other conductor from the motor |41 has electrical connection to a metal disc |48 non-rotatably mounted on shaft |04 and having a nger |50 integral therewith. Rotation of the operating shaft causes 55 the finger to engage one of the spaced contacts |5| mounted on the insulating member |52 -loosely mounted on shaft |04.

By the above construction of electric switch it will be seen that rotation of finger |50' in either direction will engage a 'contact |5|, causing corresponding rotation of the insulatingmember |52.` Further rotation of the finger and member |52 will presently cause engagement between the contact |5| carried by the member and a contact |44 on insulating plate |43. When this engagement takes place the circuit to the electric motor is closed, causing rotation of the drive |20 and the clutch member |24. Simultaneously with 70 rotation of the contacts to close the motor rotation of the spiral |36 has also occurred since it is mounted on shaft |04. Any rotation of the spiral will impart lateral movement to arm |33 to cause movement of the clutch member axially 75 of shaft |20, engaging the rclutch member with one of the pulleys |22 or |23.

Association of the control parts according to the present invention provides for simultaneous actuation of the snubbing rollers and the clutch members, the device functioning, however, to actuate the switch in advance of complete association of the clutch members so that the circuit to the motor is closed starting the motor in time to facilitate the clutching operation. Thus it will be seen that by rotation of shaft |04 from the vertical position of handle ID3 to one of its full oblique positions will release the snubbing means and associate the clutch member with one of the pulleys on shaft |20 and will then close the circuit to the motor, resulting ink rotation of the drive shaft and of the desired drum for winding the duplicating band. In addition to the above the end roller 14 is also actuated through rotation of shaft |04 in a clockwise direction. 'I'hrough links I I2 vertical levers |03 and arm 15 the roller is raised lto a position where the duplicating band is lifted olf of moistening roller 9|) and the wiping members 92. It is only when the duplicating band is wound on drum 51 that moisture should not be applied to the surface of the band and accordingly the structure is so designed as to be operative in this instance but inoperative when the band is wound on drum 6 I.

The particular construction of the electric switch is such that immediately upon rotation of shaft |64 in a direction to locate the handle |63 vertically the circuit to the motor is broken. 'I'his occurs through separation of the metallic finger |50 with a contact |5|. This operation is necessary since in order to disconnect the clutch member with its engaged pulley rotation of the parts must be discontinued. Stopping of the motor in advance of the separation of the engaged clutch faces results in easy separation, eliminating unnecessary strain on the mechanism and also on the operator.

Although the preferred showing represents the snubbing rollers as mounted for movement toward and away from stationary brake shoes it has been found that a reverse of the above operations is equally eicient for snubbing portions of the duplicating band to maintain the same in stretched condition over the printing bed. In Figures 8, 9 and 10 the

shafts

66 and 19 having suitably mounted thereon the snubbing

rollers

65 and 18, respectively, are journaled in bearings 96 stationarily mounted in the depending supports 95, the same being secured at their upper ends to a depending flange of the longitudinal beams 32, as shown in Figure 4. In this modification a separable brake shoe 93 is associated with each roller, the shoe being arcuate and being adapted to contact that portion of the band between the snubbing rollers and the shoe and having securement at their ends, respectively, to end plates 94 extending substantially parallel with the depending support 95.

For actuating the brake shoes an actuating shaft ISB is rotatably mounted by means of bearings IGI in the supports and has secured to its projecting ends cranks |62 to which is pivotally secured at |63 the actuating links |61. Non-rotatably secured to shaft |66 at the points inwardly of the end plates 94 are levers |64 having connection by means of coil springs |65 to L- shaped members |66 and |61, the members being secured to lend plates Sil, the former having securement to the left hand plate while the latter is secured to the right hand plate. It will be noted that the members extend to opposite sides of the lever |64 so that rotation of the lever in a clock-wise direction and serve to cause reciprocation of the vend plates in opposite directions forcing the shoes toward their snubbing rollers. Due to the resilient connection by springs |65 between the lever and the end plates the shoes are applied to the duplicating band in a resilient yielding manner.

The invention contemplates safety means for automatically breaking the circuit to the motor H5 .in advance of completely unwinding'theduplicating band from either of the drums 51 or 6|. Since the mechanism is substantially concealed from view the operator would otherwise not be aware of the fact that the last convolution is being unwound and stripping of the band from the drum would result. The electric circuit as shown in Figure 16 is provided with a plurality of switches |10 of the snap acting type, a switch being suitably supported by bracket |1| adjacent each drum substantially as shown in Figure 11. Suitably secured to the periphery of each drum at points substantially inwardly of one end of the drum is a resilient strip |12 having secured to its free end and projecting a slight distance beyond the drum a block |13 provided with a diagonal rim |14 on its face. A metal frame |15 provided with adjusting screw |16 is suitably secured to the drum and forms a guard for the block |13 resiliently urged into contact with screw |16 by the action of the resilient strip |12.

As shown in Figure 12, an end of the duplicating band i6 is suitably secured to the periphery of the drum, to one side of the resilient strip, and is wound thereon so that the first convolution laps over the resilient strip, forcing the same into contact throughout its length with the drum and thus causing the block |13 to assume its lowermost position within the frame. Additional winding of the band upon the Adrum has no eifect whatever upon the switch actuating structure and in order to understand the operation it will be assumed that the lever of the snap switch is in position to close the electrical circuit to the motor the parts being associated as shown in Figure 15, where it will be seen that the rotation of the drum and the switch actuating structure does not effect actuation of the snap switch |10. 'Ihe drum continues to unwind the duplicating band until the last revolution releases its engagement withthe resilient strip, whereupon the block |13 is forced upwardly to its uppermost position in frame |15, the action resulting in locating the diagonal lug |14 in the path of the operating lever of the snap switch, Continued rotation of the drum will cause engagement between the lever of the snap switch and the diagonal rib, as shown in Figure 12, causing the switch to be actuated in a direction to break the circuit to the motor, whereupon the unwinding operation automatically stops.

Since the band was being wound on the other drum during the above operation the snap switch associated therewith has its circuit to the motor closed so that it is only necessary for the operator to actuate the shaft |64 and the controlling switch associated therewith to cause the drums to reverse their direction of rotation. In the winding operation the rotation of the drum is in a clockwise direction, as shown in Figure 13, and the lapping of the first convolution on the drum positions the block and rib adjacent the periphery of the drum, whereupon further rotation brings the diagonal rib into engagement with the operating lever of the snap switch and causing operation of the switch to again close its circuit to the motor. By the above described structure the motor is automatically stopped in advance of the complete unwinding of the band from the drums so that it is impossible to strip the same therefrom.

It is to be understood that we do not wish to be limited by the exact embodiment of the device shown, which is merely by way of illustration and not limitation, as various and other forms of the device will of course be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

We claim:

1. In a duplicator, a frame having a printing bed, rollers located at the respective ends of the bed, spindles journaled in the frame and spaced from each other, a duplicating band supported on the bed and passing over the end rollers, the respective ends of the band being wound on the spindles, and means engaging the band for holding the portion on the bed in stretched condition.

2. In a duplicator, a frame having a printing bed, rollers located at the respective ends of the bed, spindles journaled in the frame and spaced from each other, a duplicating band supported on the bed and passing over the end rollers, the respective ends of the band being wound on the spindles, and means engaging portions of the band in advance of each spindle for holding the band in stretched condition on the platen.

3. In a duplicator, a frame having a printing bed, rollers located at the respective ends of the bed, spindles journaled in the frame and spaced from each other, a duplicating band supported on the bed and passing over the end rollers, the respective ends of the band being wound on the spindles, and snubbing means engaging portions of the band in advance of each spindle for holding the band in stretched condition on the platen.

4. In la duplicator, a frame having a printing bed, rollers located at the respective ends of the bed, a duplicating band supported on the bed and passing over the end rollers, snubbingrollers journaled in the frame below the printing bed and having contact with respective end portions of the band, and rotatably mounted spindles upon which the ends of the band are wound.

5. In a duplicator, a frame having a printing bed, rollers located at each end of the bed, a duplicating band supported on the bed and passing over the end rollers, spindles journaled inthe frame for winding the ends of the band, a snubbing roller contacting portions of the band in advance of each spindle, and means associated with each roller for gripping the,l contacted portion of the'band to hold the band in stretched condition on the bed.

6. In a duplicator, a frame having a printing bed, a duplicating band supported on the bed, spindles journaled in the frame on which the ends of the band are wound, snubbing rollers contacting portions of the band below the bed, and a brake shoe associated with each roller, whereby the contacted portions of the band are gripped for holding the band in stretched condition on the bed.

'7. In a duplicator, a frame having a printing bed, a duplicating band supported on the bed, spindles journaled in the frame on which the ends of the band are wound, snubbing rollers contacting portions of the band below the bed, a brake shoe associated with each roller,l whereby the contacted portions of the band are gripped for holding the band in stretched condition on the bed, and means mounting the snubbing rollers for movement to release their grip on the band.

8. In a duplicator, a frame having a printing bed, a duplicating band supported on the bed, spindles journalled in the frame on which the ends of the band are wound, and means for gripping portions of the band in advance of each spindle for holding the band in stretched condition on 'the platen, said means distributing its pres- 10 sure over a large area to prevent injury to the duplicating surface of the band.

9. In a duplicator having a printing bed, a duplicating band supported on said bed, spindles on which the ends of the band are wound, means for maintaining the portion of the band on the bed in stretched condition, a control handle operatively connected to the means for releasing the same, a motor drive, and connections from the drive to the spindles for rotating the spindles, and an electric switch operated by the control handle forvmaking and breaking the circuit to the motor.

10. In a duplicator having a printing bed, a duplicating band supported on said bed, spindles on which the ends of the band are wound, means for maintaining the portion of the band on the bed in stretched condition, a control handle operatively connected to the means for releasing the same, a motor drive, connections from the drive to the spindles for rotating the spindles, clutch means on the motor drive permitting selective rotation of the spindles through actuation of the control handle, and an electric switch operated by the control handle for making and breaking the circuit to the motor.

1l. In a duplicator having a printing bed, a duplicating band supported on said bed, spindles on which the ends of the band are wound, means for maintaining the portion of the band on the bed in stretched condition, a control handle operatively connected to the means for releasing the same, a motor drive, connections from the drive to the spindles for rotating the spindles, a clutch member on the drive, means connecting the member with the handle permitting selective rotation of the spindles through actuation of the handle, and an electric switch operated by the control handle for making and breaking the circuit to the motor.

12. In a duplicator having a printing bed, a duplicating band supported on said bed, spindles upon which the ends of the band are wound, a motor drive, connections from the drive to the spindles for rotating the spindles, clutch means en the drive, a control handle actuating the means for selectively rotating the spindles, and an electric switch operated by the control handle.

13. In a duplicator having a printing bed, a duplicating band supported on said bed, spindles upon which the ends of the band are wound, a motor drive, connections from the drive to the spindles for rotating the spindles, clutch means on the drive, a control handle actuating the means for selectively rotating the spindles, and an electric switch operated by the control handle, said switch being operative to close the circuit to the motor prior to complete actuation of the clutch means and to break the circuit in advance of actuation of the clutch means.

14. In a duplicator, a frame having a printingl bed, a duplicating band supported on the bed, spindles journalled in the frame for winding the ends of the band thereon, snubbing rollers mounted for rotation and having contacting engagement with the rear surface of the band below the bed, and a brake shoe associated with each roller, means mounting the shoes for reciprocation, and actuating means having connection to the shoes respectively and being operative upon rotation of the same in one direction to force the shoes into engagement with the band on the rollers.

15. In a duplicator, a frame having a printing bed, a duplicating band supported on the bed and having its ends wound on spindles, snubbing rollers contacting the band at points intermediate the ends of the bed and the spindles, respectively, and slidably mounted brake shoes for engaging the band on the rollers and holding the portion on the printing bed in stretched condition.

16. In a duplicator, a frame having a printing bed, a duplicating band supported on the bed and having its ends wound on spindles, snubhing rollers contacting the gelatin surface oi the band at points intermediate the ends of the bed and the spindles, respectively, a slidably mounted brake shoe associated with each roller respectively, and means for actuating said shoes simultaneously and in opposite directions, said shoes when moved in one direction serving to grip the band between the rollers and shoes.

17. In a duplicator, a frame having a printing bed, a duplicating band supported on the bed and having its ends wound on spindles, snubbing rollers contacting the gelatin surface of the band at points intermediate the ends of the bed and the spindles, respectively, a slidably mounted brake shoe associated with each roller respectively, means for actuating the shoes simultaneously and in opposite directions including a pivoted lever having connection at one end to one shoe and at the other end to the other shoe, said connections comprising springs whereby said shoes are applied resiliently.

18. In a duplicator having a printing bed, a duplicating band supported on the bed, spindles upon which the ends of the band are wound, a motor drive operatively connected to the spindles for rotating the spindles, and means on the same operating to break the circuit to the motor in advance of completely unwinding the band therefrom.

19. In a duplicator having a printing bed, a duplicating band supported on the bed, spindles upon which the ends of the band are wound, a motor drive operatively connected to the spindles for rotating the spindles, a switch electrically connected in the motor circuit and located adjacent each spindle respectively, and means on the spindles operating to actuate the switch to break the circuit to the motor in advance of cornpletely unwinding the band` therefrom.

20. In a duplicator having a printing bed, a duplicating band supported on the bed, spindles upon which the ends of the band are wound, a motor drive operatively connected to the spindles for rotating the spindles, a switch electrically connected in the motor circuit and located adjacent each spindle respectively. and means on the spindles operating to actuate the switch to break the circuit to the motor in advance of completely unwinding the band therefrom, said means upon reverse rotation to rewind the band on the spindle actuating the switch to close the circuit.

21. In a duplicator having a printing bed, a duplicating band supported on the bed, spindles upon which the ends of the band are wound, a

motor drive operatively connected to the spindles for rotating the spindles, a switch electrically connected in the motor circuit and located adjacent each spindle, and a resilient strip secured to the periphery of each spindle and held in con tact therewith by the band on the spindle, said strip upon being released projecting in the path of the switch.

22. In a duplicator having a printing bed, a duplicating band supported on the bed, spindles upon which the ends o f the band are wound, a

motor drive operatively connected to the spindles bed, spindles journaled in the frame and spaced 25 from each other, a duplicating bandl supported on the bed and having its ends woundon the spindles, and means engaging the band at points intermediate the bed and spindles, respectively,

for holding the portion on the bed in stretched 30 condition.

24. In a duplicator, a frame having a printing bed, spindles journaled in the frame and spaced from each other, a duplicating band supported on the bed and having its ends wound on the spindles and means engaging portions of the band in advance of each spindle for holding the band in stretched condition on the bed.

25. A duplicator of the class described, in combination, a frame having a printing bed, a duplicating band supported on the bed, spindles journaled in the frame upon which the ends of the band are wound, and snubbing means located below the printing bed and having contact with respective portions of the band to hold the portion on the bed in stretched condition.

26. A duplicator of the class described, comprising a frame, a platen supported by said frame, a pair of spindles journaled therein, a duplicating band having its ends wound on the spindles and passing over the platen, and moistening devices supported by the frame, one of said devices including a moistening roller and a squeegee located to one side of the roller, said roller contacting the band for applying moisture thereto and the squeegee contacting the band and functioning to remove the excess moisture therefrom.

27. In a. duplicator, a platen, spindles journaled adjacent the ends of said platen, a duplicating band having its ends wound on said spindles and having its intermediate portion disposed over said platen, power driven means for unwinding said band from one of said spindles and rewinding it on the other of said spindles, and automatic means for rendering said power driven means functionally inoperative before the band is completely unwound from the first spindle.

28. In a duplicator, a platen, a pair of spindles journaled adjacent the ends of said platen, a duplicating band having its ends wound around the spindles and having its intermediate portion disposed over said platen, power driven means for Y unwinding said band from one of said spindles and rewinding it on a second spindle, and automatic means for rendering said power driven wind it on the other of said spindles, and a manually actuated handle for controlling Said clutches and for stopping and starting said power driven means.

30. In a duplicator, a platen, a pair of spindles, a duplicating band having its ends wound around the spindles and having its intermediate portion disposed over said platen, power driven means for unwinding said band from one of said spindles and rewinding it on a second spindle, means for moistening said band, and common manually actuated means for controlling said power driven means and for displacing said moistening means into and out of contact with said band.

31. In a duplicator, a platen, spindles, a duplicating band having its ends wound around the spindles and having its intermediate portion disposed over said platen, and movably mounted Y means engaging said band intermediate said spindles to hold it taut over said platen.

32. In a duplicator, a platen, a pair of spindles, a duplicating band having its ends wound around the spindles and having its intermediate portion disposed over said platen, power driven means for unwinding said band from one of said spindles and rewinding it on a second spindle, and means including means carried by one of said spindles for rendering said power driven means function- -ally inoperative when said duplicating band is substantially completely unwound from the rst spindle.

33. In a duplicator, a platen, a pair of spindles, a duplicating band having its ends wound around the spindles and having its intermediate portion disposed over said platen, movable means engaging said band intermediate said spindles for drawing it taut over said platen, means for moistening said band and common manually actuated means for controlling said movable means and for displacing said moistening means into and out of contact with said band.

34. In a duplicator, a platen, spindles journalled adjacent the ends of said platen, a duplicating band having its ends wound on said spin- `dles and having its intermediate portion disposed on said platen, power driven means for unwindingsaid band on one of said spindles and rewinding on the other of said spindles, and means operated by removal of the band from said rst named spindle for rendering said power driven means functionally inoperative before the band is completely unwound from the first named spindle.

35. In a duplicator, a platen, a pair of spindles, a duplicating band having its ends wound around the spindles and having its intermediate portions disposed on said platen, power driven means, means for selectively causing said power driven means to rotate said spindles to unwind the band from either of said spindles and rewind it on the other of said spindles, and means controlled by the removal of said band from either of said spindles for rendering said power driven means functionally inoperative before the band is completely unwound from either spindle.

36. In a duplicator, a platen, spindles journalled adjacent the ends of said platen, a duplicating band having its ends wound on said spindles and having its intermediate portion disposed on said platen, power driven means for unwinding said band from one of said spindles and rewinding it on the other of said spindles, and means controlled by the amount of the band on one of said spindles for rendering the power driven means functionally inoperative-to completely unwind the band from the first spindle.

JAMES K. DUNCAN. DEAN H. WHITEHEAD. JOSEPH M. CHENEY.