US1987923A

US1987923A - Duplicating machine

Info

Publication number: US1987923A
Application number: US613845A
Authority: US
Inventors: Ernest J Brasseur
Original assignee: AB Dick Co
Current assignee: AB Dick Co
Priority date: 1932-05-27
Filing date: 1932-05-27
Publication date: 1935-01-15
Anticipated expiration: 1952-01-15

Description

Jan. 15, 1935. J, BRASSEUR 1,987,923

DUPLICATING MACHINE Filed May 2'7, 1932 3 Sheets-Sheet 2 J/ was J/jraasew Jan. 15, 1935. E. J. BRASSEUR 1,987,923

DUPLICATING MACHINE Filed May 27, 1952 5 Sheets-Sheet 3 IIIIIIIIIIIIIIIIII, 'IIIIIIIIIIIIIIIIIIIIII/llfl IIlIIIIIIIlIIIIIIIl/IIIII!IIIlIIIIIlllIIIllIIII/IIIIIIIIIIW Patented Jan. 15, 1935 UNITED STATES PATENT OFFICE A. B. Dick Company, Chicago,

tion of Illinois 111., acor'pora- Application May :1, 1m, Serial No. 01am 6 Claims. (cam-us) This invention relates to duplicating machines and the like, and more particularly stencil duplicating machines wherein a sheet of paper fed into the machine is frictionally enaged between the rotatable drum and an impression roller so as to be drawn through the machine in close engagement with the drum and to receive an impression from the stencil thereon. After passing through the printing couple of the machine, the impression sheet is diverted from the path of the drum and forwarded to a receiving device, such as a tray, in which the successive sheets are delivered in a pile or stack. To divert the sheet from the 13 drum and overcome its natural tendency to adhere to the stencil, it has heretofore'been the practice to engage the edges of the sheet under stripping fingers arranged close to the periphery of the drum adjacent the ends thereof, and

having a difierent curvature of greater radius than the drum. These fingers lead the forward corners of the sheet away from the drum after passing through the printing couple, and in conjunction with suitable guides cause its leading edge to follow a path substantially tangent to the drum surface.

Such devices are quite effective in the stripping of sheets of average width, but considerable difificulty has been experienced in mag chines having long drums, such as are used in the printing of the wider sheets, caused by the adherence of the central portion of the sheet which pulls the edges thereof from under the strippers. This trouble is particularly marked 86 in the use of thin sheets, or with thick, tacky inks, and is accentuated when the machine is cold. When it occurs, the sheet crumples and winds around the drum, necessitating stopping the feed and clearing away the damaged sheet 40 or sheets, which leads to much annoyance and loss of time and paper. 1

One of the objects of this invention is to provide a duplicating machine in which these difliculties are avoided'and bywhich sheets of any width are eifectively stripped from the drum regardless of their width and stiilnesaof the character of the ink, the temperature, or any other condition of operation.

Another object of the invention is to provide stripping means for duplicating machines of the character designated, by which each sheet is positively deflected away from thestencil drum.

across the entire width of its leading edge at the 55 proper time in the cycle of the machine.

Another object of the invention is to provide a stripping device inwhich the sheet shall be separated from the drum and stencil by the force of compressed air, discharged in jets ar- 80 ranged in a row extending across theentire stripping is insured.

Other objects of the invention will appear from the following description, taken in connection with the drawings, which form a part of this specification and in which:

Fig. 1 is a perspective view of part of the delivery end of a duplicating machine constructed in accordance with the invention, partly broken away to show certain features of the structure;

Fig. 2 is a view, partially in end elevation and partially in longitudinal section, through the duplicating machine shown in Fig. 1;

- Fig. 3 is afragmentary detail view of the stencil clamping. bar of the machine, cut away to show the manifold construction;

Fig. 4 is an end elevation of the stencil carrying drum, showing the supports therefore and Fig. 6 is a perspective viewof the "drum supporting bearing member.

Referring to the drawings, at 10 is indicated.

generally a rotary duplicating machine having side frame members such as 11, between which a stencil carrying cylinder or drum 12 is rotatably mounted on journal members or trunnions 13 supported in the frame members. The drum 12 may be of the well known construction comprising end portions or heads 14 and a perforated, stencil carrying portion 15 formed as a segment of a cylinder, and the length of the drum between the heads may be suitable for use with sheets of any desired width, the present invention being particularly well adapted for use with the wider sheet. An impression roller 16 is rotatably mounted between the frame members 11 beneath the drum 12, and is adapted to cooperate with the drum in the well'known manner to form "the printing couple of the machine. The cylindrical portion 15 of the drum is perforated with a large number of small closely spaced holes 17 through which ink may pass from the interior of the drum to an ink pad 18 mounted on the surface 15, and over which a stencil 19 is stretched as is well understood. When the drum is rotated and a sheet of paper or other suitable impression material 20 is with the stencil 19, an impression of the matter written, drawn, or typed on the stencil is formed on said sheet in a manner well understood in the art to which this invention relates.

The ink pad 18 is provided at its ends with suitable means such as rods 21, the ends of which may be removably engaged in holes or sockets (not shown) provided in the heads 14, or in suitable tensioning devices inside the stencil carrying portion to stretch the pad around the surface 15. The stencil 19 is provided at its head end with a reinforced strip or stub member having the usual button holes 22 which are engaged with pins 23 on a bar member or strap 24 extending across the drum between the heads 14. A clamping abutment 26 is provided at the edge of the surface 15, and the stencil 19 is stretched over this abutment and around the drum in close contact with the pad 18,'its other end passing over a similar clamping abutment 27 at the other end of the surface and being secured thereto by a clamping bar 28 having pivoted arms 29 which are urged by suitable springs 31 to maintain the bar in clamping engagement with the abutment.

A clamping member 32 is also provided for cooperation with the abutment 26 for clamping the stencil and the pad at the leading edge thereof. As shown, this member is in the form of a movable bar provided with radially disposed integral end arms 33, having hubs 34 which are mounted to pivot about the axis of rotation of the drum. Suitable toggle means 36 is provided between each of the arms 33 and the adjacent drum head 14 by which the mem ber 32 may be swung toward the abutment 26 to clamp the pad and stencil there-between with a considerable pressure, and to lock the member 32 in clamped position. The member 32 is provided with a surface 37 which forms a continuation of the cylindrical surface 15, and it is made hollow with closed ends, as shown, for a purpose to be described.

The journal member 13 has a bearing portion '41 on which a drum bearing 42 is mounted to rotate, and this drum bearing is formed with a portion 43 of reduced diameter defining a bearing surface 44 on which the hub 34 is mounted to rotate with the drum and also to pivot with respect. thereto. The bearing trunnion 13 is also provided near its end with a tapered shoulder portion 46 which is drawn into cooperative engagement with a corresponding surface formed in the hub 34 by a nut on a threaded extension 47 of the trunnion. This construction retains the hub 42 in proper axial position and also provides an air-tight seal between the trunnion and the hub 34. A pulley 48 is also journaled on the member 13 adjacent the side frame member, its hub 49 being axially spaced from the hub 42 by a sleeve 51 surrounding the member 13. The pulley 48 may be driven by a belt 52 from a motor or-other suitable source of power, and any convenient means may be provided for detachably connecting the pulley to the drum in driving relation. As motors and clutch devices suitable for such drives are well known, and as they form no part of this invention, the specific construction is not illustrated.

The delivery side of the machine is provided with suitable sheet forwarding means. adapted to advance the impression sheets from the printing couple. As shown, this comprisesa pair of friction rollers such as 53, splined to and driven from a shaft 54 mounted in suitable bearings in through the printing couple, to

, surface of the member 32 and may the side frame members and which may be driven from the machine in any convenient manner, not shown. There is one of the rollers 53 at each side of the machine and the hub of each of these rollers is disposed between

arms

56 and 57 of a forked yoke member 58, the shaft 54 passing through holes provided in the arms. The member 58 is mounted on a crossbar 59 secured to and between the frame members 11, and it may be adjustably secured thereon by locking means such as a screw 61. In this way the rollers 53 may be adjusted laterally of the machine to the width of the sheets being printed, so that the edge portions of each sheet pass over the rollers. The outer arm 57 of each yoke 58 is extended upwardly and pivotally supports, as at 62, a lever 63 having a pin 64 on which a roller 66 is journaled to rotate in contact with the edge portion of the sheet above the roller 53. A suitable spring 6'7, connected between lever 63 and arm 57 holds the roller 66 in engagement with the sheet, and the sheet in turn in frictional engagement with the roller 53, so that this driven roller 53 operates to positively withdraw the sheet advanced by the printing couple. Suitable rails 68, carried by arms 69 which are secured to and adjustable on the crossbar 59, support the central portion of the sheet between the forwarding rollers 53, and

preferably extend forwardly and downwardly from adjacent the impression roller 16.

Secured to and extending rearwardly from each of the arms 57, in close proximity to the periphery of the drum head 14 is a stripper member or arm 71, which terminates at the feed end of the machine just in front of the crotch of the printing couple (not shown), and at its rear end just in advance of the crotch between the

forwarding rollers

53 and 66. In feeding the sheet tothe printing couple, its side edges are engaged beneath the members 71, and as is well known, these members move the leading corners of the sheet tangentially away from the cylindrical drum surface after passing strip the printed sheet from the stencil. However, in the practical operation of such machines, it frequently happens that the adherence between the central portions of the stencil and the printed sheet, particularly at the leading edge thereof, is sufficient to carry the central portion of the sheet around the drum with the stencil, drawing the edges of the sheet laterally from under the strippers '71. When this happens, the sheet so carried around is crumpled and spoiled, and in turn blocks the passage of succeeding sheets, so that frequently a number of sheets are wasted before the operator can stop the machine, which must then be cleared and restarted.

The pneumatic stripping means of this invention'is carried by the drum and is operative on the entire width of the printed sheet along the leading edge thereof to obviate the difficulties described. As shown in the drawings, it comprises a manifold '12, formed by the hollow clamping member 32, and a number of small holes or ports 73 extending in a row along the member 32 and terminating in the surface 3'] thereof, which communicate 'with the manifold. These ports are placed close to the clamping be disposed substantially radially of the drum. The manifold is supplied with air under pressure from any convenient source (not shown), which may be a compressor driven from the machine or tling groove 81, and the port 83.

from a separate motor mounted on or adjacent the machine. Such source of compressed air is connected to a duct or passage 76 provided in one of the side frames 11, and which terminates in a port 77 at the journal member 13. This journal member is provided with a longitudinal passage 78 having a port 79 at its outer end adapted to register with the port 77, whereby the passage 76 is in communication with the passage 78. The inner end of the bearing member 13 is provided with throttling means comprising a shallow circumferential groove 81, formed in the reduced bearing portion 44 and arranged in the plane of rotation of the hub 34, which groove is connected to the passage 78 through a metering port 82. The hub 34 is provided with a port 83 in registry with the groove 81, which port communicates through a conduit 84, carried by or formed in the end arm 33, with the manifold 72.

The

ports

82 and 83 are of substantially the same size, and are adapted to come into aligned position once during each revolution of the drum. The number 13 is retained in position with the ports 77 and '79 in registry by locking means, such as a pin 86, and the angular relation of the ports 82 and 7'7 about the axis of rotation is such that the

ports

82 and 83 come into alignment just as the leading edge of the sheet emerges from the crotch of the printing couple. I

It will be seen from the above description, that in operation there is a small continuous flow of air under pressure through duct 76 and passage 78 to conduit 84 and the manifold 72, which flow takes place through port 82, throt- Groove 81, however, restricts this flow and only permits the by-passing or leakage of suflicient air to prevent the operation of the pressure relief means usually provided on the compressor or other source of pressure air, and therefore acts as a pressure reducing means to keep the air pressure in the manifold '72 at a low point during the major portion of the revolution of the drum. As the impression sheet emerges from the printing couple, however, there is a short interval in which

ports

82 and 83 are aligned to form a direct and unthrottled connection, which permits a sudden and considerable increase of pressure in the manifold and a corresponding increase in the discharge of air through the ports 73. This air is discharged between the drum surface and sheet 20, and forces or blows the leading edge of the sheet away from the drum as clearly shown in Fig. 2, stripping it completely from the stencil across its entire width adjacent the leading edge. Shortly after stripping is thus commenced the corners of the sheet are engaged between the

rollers

53 and 66, which forward it to the receiving device in the usual way.

It will be evident that this invention provides means in which the sheet is separated from the stencil not only at its side edges but across its entire. width, thus effectively preventing adherence at the central portion of the leading edge from carrying the sheet around the drum. It will also be seen that as the stripping air is discharged between the sheet and the drum, the action is independent of the width or stiffness of the sheet, and the adhesiveness of the stencil, and operates as well with wide, thin sheets and with cold, tacky inks as it does under the more favorable operating conditions.

While a specific embodiment of the invention has been herein described, which is deemed to be new and advantageous and may be specifically claimed, it is not to be understood that the invention is limited to the exact details of the construction, as it will be apparent that changes may be made therein without departing from the spirit or scope of the invention.

Having thus described the invention, what is claimed and desired to be protected by Letters Patent is:

1. In a duplicating machine having a stencil carrying drum provided with an axially disposed bearing, a discharge manifold carried by the drum, a conduit connecting the manifold to the bearing and terminating in a port in the bearing surface, a fixed journal cooperating with said bearing having a circumferential groove in registry with said port, and means including a passage in said journal communicating with said port to supply air under pressure to said manifold.

2. In a duplicating machine having a rotary stencil carrying drum, a discharge manifold carried by said drum, a bearing for said drum, 2. metering port carried by said bearing and connected to said manifold, means including a conduit adapted to supply air under pressure to the manifold through said port during a portion of the drum rotation, and flow restricting means adapted to supply a lesser quantity of air to said port throughout the remainder of the drum rotation.

3. In a duplicating machine having a printing element rotatable to advance an impression sheet, a manifold adapted to continuously discharge air under pressure between the printing element and the impression sheet, and means including registrable ports to supply air under increased pressure periodically to said manifold.

4. In a duplicating machine having a printing element rotatable to advance an impression sheet, a manifold adapted to discharge air under pressure between the printing element and the impression sheet, and means to supply air under pressure to said manifold, said means including a throttlingpassage and means to bypass said passage in timed relation to the printing element.

5. In a duplicating machine having a printing element with an inked surface and rotatable toadvance an impression sheet in contact therewith, means carriedby said printing elementto continuously discharge air at the surface of said element, and means to increase the pressure of the discharged air to strip the impression sheet from said inked surface.

6. In a duplicating machine having a stencil carrying drum, a stencil clamp pivotally mounted on said drum and forming a part of the drum surface, air discharge ports in said drum surface portion of 'the stencil clamp, means to continuously discharge air at low pressure through said ports, and means controlled by rotation of the drum to periodically increase the pressure of the air discharged.

ERNEST J. BRASSEUR.