US2730042A

US2730042A - Stencil duplicating machines

Info

Publication number: US2730042A
Application number: US231072A
Authority: US
Inventors: Styles Leonard Walter; Picking Henry John
Original assignee: NRG Manufacturing Ltd
Current assignee: NRG Manufacturing Ltd
Priority date: 1951-06-12
Filing date: 1951-06-12
Publication date: 1956-01-10
Anticipated expiration: 1973-01-10

Description

Jan. 10, 1956 L. w. STYLES nu. 2,730,042

STENCIL DUPLICATING MACHINES Filed June 12, 195] 4 Sheets-Sheet 1 0 @(DQQO in (J 62 127260.03

Jan. 10, 1956 L. w. STYLES ETAL STENCIL DUPLICATING MACHINES 4 Sheets-Sheet 3 Filed June 12, 1951 i121) ezzfbors PZL ck 612;

Jan. 10, 1956 1.. w. STYLES ETAL 2,730,042

STENCIL DUPLICATING MACHINES Filed June 12, 195] 4 Sheets-Sheet 4 .IZZUiZZTZFOfi L .H. 5129 Z65 UnitedStatesPatentO STENCIL DUPLICATING MACHINES Leonard Walter Styles and Henry John Picking, Tottenham Hale, London, England, assignors to Gestetner Limited, London, England Application June 12, 1951, Serial No. 231,072 3 Claims. (Cl. 101-122) This invention relates to stencil duplicating machines of. the kind comprising a plurality of cylinders over which a flexible so-called silk gauze support for the stencil is caused to travel. The silk gauze support is secured to a rigid transverse memberengaged at each end with a flexible band and which as a whole may be referred to as a stencil carrier.

In previous arrangements what may be described as ballooning occurs, that is to say separation between the stencil and the gauze adjacent the transverse member.

Furthermore, a large number of pins are necessary to secure the heading of the stencil in order to ensure an even pull thereon from the part of the stencil adhering to the gauze.

For the same reason the stencil has been sandwiched between two layers of the heading material.

Also after use owing to the pull on the heading the latter is held tightly on the pins so that it is not easily released and the stencil is therefore usually removed from the trailing end first which is inclined to result in dirtying of the hands.

An object of the invention is to provide improved means for securing the stencil to the carrier in order to avoid ballooning of the stencil.

A further object is to provide an arrangement for securing the heading of the stencil to the transverse member in such a manner that the stencil can be easily removed after use by first removing the heading.

A further object is to provide an arrangement for securing the heading" of the stencil requiring only a small number of pins for locating it.

A further object is to provide an arrangement in which the stencil can be secured to its heading by simple adhesion on one side.

According to the invention a transverse lip member is provided adapted to be brought down over the stencil adjacent the transverse member when the stencil has been fitted on the carrier, so that the stencil is bent against the straight line edge of the transverse lip.

By this means the pull from the part of the stencil adhering to the gauze is taken on the straight edge of the lip and the strain on the junction of the stencil with the heading and of the heading on the pins is considerably reduced.

Conveniently, also, the lip holds the silk gauze support and stencil in contact with each other.

Preferably the transverse lip member forms a hinged spring cover for the transverse member.

Conveniently holes are formed in the cover so that the latter fits over pins provided in the transverse member for locating the heading of the stencil.

A projecting member may be provided on the hinged spring cover adapted to co-operate with a stud or the like on the appropriate cylinder for holding the cover open at the appropriate position for fitting and removing a stencil and for releasing the cover so that it may close automatically when the transverse member is turned away from said appropriate position.

Vii

ICE

The projecting member may be a reciprocating springloaded pawl.

The invention will be further described with reference to the accompanying drawings.

Figure 1 is a plan view with the securing means open.

Figure 2 is a plan view with the securing means closed.

Figure 3 is a diagrammatic section on the line III-III of Figure l.

Figure 4 is a fragment of an enlarged section of Figure l on the line IV-IV with the stencil carrier and stencil in position. i

Figure 5 is a fragment of an enlarged section of Figure 2 on the line V-V also with the stencil carrier and stencil in position.

Between the two endless bands 1 forming part of the stencil carrier there is secured a transverse member 2 secured at each end to the respective band by means of clips 20 and comprising two elements 20! and 2b hingedly connected together. The upper or outer element 2a which will be referred to as the lip member is furnished With a turned-over lip 2a, and is associated with a spring or a plurality of springs 3 adapted to urge the elements towards one another so that the lip will bear upon the stencil in a direction generally at right angles thereto at the point of contact and bend it about the edge of the lip bringing it against the gauze. A projection in the form of a pawl element 2a extends in a rearward direction from the element 2a at one end thereof, and is adapted to co-operate with pins or studs 4 provided adjacent one end of the upper cylinder 5 which engages the pawl element to hold the element 2a in the open position when it has been raised to facilitate engaging the stencil with the carrier.

On the element 2b there are provided pins 2b of any appropriate form adapted to be engaged in holes provided in the heading of the stencil '7 and in the rigid strip 6 with which one end of the gauze 8 is secured.

The pins or studs 4 on the cylinders are preferably located in one of a pair of annular grooves 5a adjacent to the ends of the cylinders and between these grooves and the ends the cylinder is provided with pins 5b or the like designed to be engaged by the endless bands I forming part of the stencil carrier.

The pawl element 2a" extending in a rearward direction from the element 2a may be forced. upward or outward against spring-loading provided by spring 9 to permit of the raising of the element 2a at an appropriate position. When the element 2a is raised through more than a particular angle the pawl 2a will engage behind one of the pins or studs 4 to hold the element 2a in the raised position.

As shown, three pins or studs 4 are provided spaced at 120 around one of the grooves 5a. With the heading in position A at the crown of the upper cylinder, one of the pair of studs 4 in the groove So will be in position to engage the retaining element or pawl 2a". For each subsequent complete revolution of the heading the cylinders revolve 1% times so that another stud 4 is available when the heading returns to the crown of the upper cylinder.

The pawl element 2a" of the upper jaw may be provided with a cover-piece 2d which may also have a fingerpiece 2a" adapted to facilitate raising it manually for engaging the gauze and heading of the stencil in position. When the stencil has been fitted the element 2a may be manually lowered by forcing it downwards. If this is not done it will be appreciated that as the stencil secur ing means 2 moves downward from the upper part of the cylinder 5 owing to the increase in distance between the pawl 2a" in the element 2a and the cylinder, the element 2a will be released from its raised position so that it is snapped closed by the action of the springs 3. Similarly, release will occur if the cylinder should be turned in the reverse direction, thus ensuring that the carrier cannot circulate with the member 2a in the raised or open position.

Various modifications may be made withinthe scope of the invention.

We claim;

l. A stencil duplicating machine' compris'ing a plurality of cylinders, a pair of spaced flexible endless bands adapted to be carried round by the cylinders, a rigid transverse member engaged at its ends with the respective bands and adapted for the securing thereto of one end of a flexible silk gauze support for a stencil and of one end of a stencil, a hinged spring cover for the ends of a silk grauze and stencil so secured, a projecting memher on the hinged spring cover and a stud on at least one o f'the cylinders for engaging the projecting member to hold the cover open at the appropriate position for fitting and removing the cover and for releasing the cover so that it may close automatically when the transverse 'member is carried round by the bands away from said r mamas element to hold the cover open at the appropriate position for fitting and removing-the eover'and'for releasing theofa flexible silk gauze support for a stencil and one end of a stencil, a hinged spring cover for the ends of a silk gauze and stencil so secured, having a straight line edge, adapted to be brought down over the outside of such a stencil adjacent the rigid transverse member so that the stencil is bent back against the straight line edge of the hinged spring cover, a projecting member on the hinged spring cover, and a stud on at; least one of the cylinders for engaging the projecting member to hold the cover open at the appropriate position for fitting and removing the cover and for releasing the cover so that it may close automatically when the transverse member is carried round by the bands away from said appropriate position.

References Cited in the file of this patent UNITED STATES PATENTS 732,542 Gest etner June 30, 1903 778,449" Dick' Dec. 27, 1904 I 1,798,371 Creed Mar. 31, 1931 2,235,778 Samuels Mar. 18,1941