US2937593A - Printing foil attaching arrangement - Google Patents

Description

May 24, 1960 w. RITZVERF'ELD ETAL 2,937,593

PRINTING FOIL ATTACHING ARRANGEMENT 6 Sheets-Sheet 1 Filed Feb. 25. 1957 y 1960 w. RITZERFELD ET AL 2,937,593

PRINTING FOIL ATTACHING ARRANGEMENT Filed Feb. 25, 1957 6 Sheets-Sheet 2 M y 2 1 w. RITIZERFELD ET AL 2,937,593

PRINTING FOIL ATTACHING ARRANGEMENT Filed Feb. 25, 1957 6 Sheets-Sheet 3 1 19.15 nglafiyrrfigzsfigzqF/gw 63 K n a N01 10/ 10/ f? May 24, 1960 w. RITZERFELD ETAL 2,937,593

PRINTING FOIL ATTACHING ARRANGEMENT 6 Sheets-Sheet 4 Filed Feb. 25, 1957 jm entan' l7" z 4, 1960 RITZERFELD ETAL 2,937,593

PRINTING FOIL ATTACHING ARRANGEMENT Filed Feb. 25, 1957 6 Sheets-Sheet 5 #7 .50 Z5 E r05 Q 9 my. a;

Drug/7102':

May 24, 1960 w. RITZERFELD ETAL PRINTING FOIL ATTACHING ARRANGEMENT 6 Sheets-Sheet 6 Filed Feb. 25, 1957 2,931,593 PRINTING FOIL ATTACHING ARRANGEMENT Wilhelm Ritzerfeld, Schorlerner Alice 14, Berlin-Dahlem, Germany, and Gerhard Ritzerfeld, Franzenshader Str. 21, Berlin-Grunewald, Germany Filed Feb. 25, 1957, Ser. No. 642,003

Claims priority, application Germany Dec. 23, 1954 7 Claims. (Cl. fill-415.1)

The present invention relates to a printing foil attaching arrangement, and more particularly to an arrangement in which a thin flexible printing foil consisting of paper, of synthetic resin, of paper having a metal layer thereon, or consisting ofv metal is attached to the printing drum of a duplicating apparatus.

This application is a continuation-in-part of patent application Ser. No. 553,342 filed December 15, 1955, en-

titleddTrinting Foil Attaching Arrangement, now abandone The known attaching arrangements for lithographic printing foils us'e printing foils provided with a series of perforations along the edge of theprinting foil which are engaged by corresponding hook members on the printing drum. The attaching arrangements of this type have the great disadvantage that very thin foils tear along the perforations thereof.

Other printing foil attaching arrangements are known in which the printing foil is simply clamped to the printing drum. These arrangements have the disadvantage that the inking rollers and moistening rollers which continuously run over the printing foil, frequently pull the printing foil out of the clamping means.

It is the object of the present invention to overcome these disadvantages of the known attaching arrangements for printing foils, and toprovide a printing foil attaching arrangement by which the printing foil is securely attached to the printing drum without being torn or without slipping out of the attaching means.

It is another object of the present invention to provide 'an attaching device for a printing foil provided with at least one projecting shoulder along at least one edge engaging the attaching device.

It is another object of the present invention to provide an attaching device for attaching a printing'foil in tensioned condition to the surface of a printing drum.

It is a further object of the present invention to provide an attaching device for attaching a plurality of partly superimposed printing foils to a printing drum.

Another object of the present invention is to provide a printing foil having a thickened edge portion along at least one edge thereof to form at least one projecting shoulder along the edge.

It is also an object of the present invention to provide a sheet attaching arrangement for attaching a sheet having at least one projecting shoulder to a carrier member.

With these objects in view, the present invention mainly consists of a sheet attaching arrangement which comprises, incombination, a carrier member having a surface formed with at least one elongated recessed shoulder; a sheet superimposed on the surface of the carrier member and having at least one elongated projecting shoulder engaging the recessed shoulder of the carrier member; and holding means secured to the carrier member and engaging the sheet for holding a projecting shoulder of the same in engagement with a corresponding recessed shoulder of the carrier member. v According to another embodiment of the present inven- 7 Patented May 24, 1960 tion a sheet is used which has at least along one of its edges two projecting shoulders on opposite sides of the sheet, and the holding means are also provided with a recessed shoulder for holding the projecting shoulder on the side of the sheet'opposite to that on which is located the shoulder that is held by the recessed shoulder of the carrier member. j

According to one embodiment of the present invention, the sheet is a printing foil consisting of a thin flexible material, and the carrier-member is a printing drum supporting the printing foil on the'surface thereof.

.According to a preferred embodiment of the present invention, the printing drum is provided with two recessed shoulders for holding a printing foil having two projecting shoulders at the spaced edges thereof. Preferably, one of the two recesses on theprinting drum is provided in a movable member which is engaged by resilient means to tension the printing foil on the surface of the printing drum.

Preferably, holding means are provided engaging the edge portion ofthe printing foil to hold the projecting shoulder of the printing foil in engagement with the recessed shoulder on .the drum.

In a modified embodiment of the present invention holding means are provided for engaging with a recessed shoulder the projecting shoulder on the side of the sheet opposite to that on which is located the shoulder that is held in engagement with the recessed shoulder of the drum. t

According to a modified embodiment of the present invention, the holding means is provided with another recess for engaging a projecting shoulder on, anotherprinting foil, so that two printing foils may be partly superim posed on each other.

A printing foil according to the present invention is provided at least along one edge thereof with an edge por-' tion of increased thickness which forms a projecting shoulder on one. side of the printing foil. The edgeportion of increased thickness is preferably produced on the printing foil by. bending upon itself the edge portion of the printing foil at least once and preferably twice. I The bent over edge portions are preferably adhesively, connected to each other and to the main portionof the printing foil. A .water resistant glue is advantageously used for this purpose. It is, however, not absolutely necessary to glue the turned over edge portionsof the printing foil to the main portion of the printing foil, since, the projecting edge portion of the printing foil can be held by holding means in the recess of the printing drum.

According to a modified embodiment of the present invention a printing foil is provided at least along. one edge thereof with an edge portion of increasedthickness which forms projecting shoulders on opposite sides of .the printing foil. The edge portion of increased thickness is preferably produced on the printing foil by bending upon itself the edge portion of the printing foil atleast twice on one side and then around the edge and at least once on the opposite side. The bent over edge portions are preferably adhesively connected to each other and tothe main por tion of the printing foil. In certain cases, however, it may be sufficient to bend the foil material without applying an adhesive.

Due to the fact that one or several thicknesses of the printing foil serve for holding the printing foil;'even very thin printing foils consisting of paper are reliablyheld even during along printing operation. Particularly suited for attachment according to the present invention are printing foils consisting of paper provided with a metal layer. By the attachment means according-to the present invention it is without anyditliculty possible to use sheets of paper of standard size 40g glued to a aluminum ing a thickness of'0.03-

The increased thickness of at least one edge portion of a printing foil may also be obtained by attaching to the foil a strip of material on opposite sides of the edge portions so that these strips constitute projecting shoulders on opposite sides of the foil. Instead of using two separate strips, one strip folded to U-shape may be used and the edge portion of the foil inserted between the two legs of the U.

In order to prevent lateral slipping of printing foils according to the present invention whose length is. not exactly the same as the axial length of the said recesses, it is advantageous to provide a plurality of aligning members such as pins, projections, or similar members engaging cutouts in the printing foil. These cutouts are not provided for attaching the printing foil, but for the purpose of preventing the lateral slipping of the same. Con-. sequently, the cutouts extend in circumferential direction of the printing drum through a greater distance than the thickness of the holding pins or projections so that only the lateral sides of the projections engage the lateral edges of the cutouts and a slight movement of the printing foil in circumferential direction of the printing drum is possible for adjustment. The cutouts may be provided in the thickened edge portions of the printing foil, but may also be provided in the main portion of the printing foil in the form of perforations. I

Instead of cutouts within the edge portion for the purpose set forth indentations spaced from each other extending from the edge of the edge portion in circumferential direction of the printing drum may be used with the same effect.

This additional device is of particular value in the event that the organization of the company using the device according to the present invention requires the use of printing foils of very different shapes on the same machine. In the event that several printing foils are to be used in superimposed positions, it is also very useful to have the printing foils aligned-by the aligning means according to the present invention so that no relative displacement between a plurality of superimposed printing foils is possible.

The embodiment of the present invention in which not only one edge but both edges of the printing foils are attached to the printing drum is particularly advantageous when a great number of imprints have to be taken from a printing foil.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a perspective view of a printing foil according to the present invention;

Fig. 2 is a side view of the printing foil illustrated in Fig. 1;

Fig. 3 is a side view of a modified printing foil according to the present invention;

Fig. 4 is a side view of another modified embodiment of a printing foil according to the present invention;

Fig. 5 is a side view of a further modified embodiment according to the present invention;

Fig. 6 is a perspective view of another modified embodiment of a printing foil according to the present invention;

Fig. 7 is a fragmentary sectional view taken on line A--B in Fig. 6;

Fig. 7a is a fragmentary-sectional view of a modified embodiment of a printing foil according to the present invention;

Fig. 8 is a fragmentary sectional view illustrating an embodiment of the sheet attaching means according to the present invention provided on a printing drum; l

Fig. 9 is a fragmentary side view of the embodiment illustrated in Fig. 8;

Fig. 10 is a fragmentary cross-sectional view of a modified embodiment according to the present invention taken on line A-B in Fig. 11;

Fig. 11 is a top view of the embodiment illustrated in Fig. 10;

Fig. 12 is a side view, partly in section of another modified embodiment according to the present invention, the section being taken on line A-B of Fig. 13;

Fig. 13 is a fragmentary top view of the embodiment illustrated in Fig. 12;

Fig. 14 is a fragmentary sectional view illustrating a detail of another modified embodiment according to the present invention;

Fig. 15 is a perspective view of a printing form foil having edge portions of increased thickness so as to form shoulders projecting on both sides;

Fig. 16 is a cross sectional side view of a foil composed of layers of paper and metal,,the edge portions thereof being reinforced by a strip of material enveloping the edge;

Fig. 17 is a cross sectional side view of a foil made of metal or synthetic resin, the edge portions whereof are reinforced by a strip of material;

Fig. 18 is a cross sectional side view of the edge portions whereof are reinforced by two separate strips of material attached on opposite sides of the foil;

Fig. 19 is a metal foil in cross sectional view, the edge portions being reinforced by repeated bending back upon itself of the foil material;

Fig. 20 is a cross sectional side view of a foil composed of layers of paper and metal, the edge portions thereof being reinforced by attaching strips of material to opposite sides of the foil and by an additional strip of material superimposed over said strips of material;

Fig. 21 is a plan view of a printing form foil provided with perforations in the edge portion of increased thickness;

Fig. 22 is a cross-sectional side view of the foil according to Fig. 21;

Fig. 23 is a plan view of a printing form foil provided with indentations in the reinforced edge portion;

Fig. 24 is a cross sectional side view of the printing form foil according to Fig. 23;

Fig. 25 is a transverse sectional view of a printing drum including means for attaching a printing form foil;

Fig. 26 is a transverse sectional view of a printing drum including means for attaching the forward and rear edge portions of the printing form foil;

Fig. 27 is a transverse sectional view of a printing drum including means for attaching a printing form foil according to Fig. 21 and including additional means for engaging the cutouts thereof;

Fig. 28 is a transverse sectional view of a printing drum including means for attaching a printing form foil according to Fig. 23 and including additional means for engaging the indentations thereof;

Fig. 29 is a plan view of a printing form foil with edge portions provided with projecting shoulders on both sides, said projecting shoulders being offset against each other;

Fig. 30 is a cross sectional side view of the printing form according to Fig. 29;

Fig. 31 is a transverse sectional view of a printing drum including means for holding a printing form according to Figs. 29 and 30 and including recessed shoulders offset against each other;

Fig. 32 is a top view of the printing drum according to Fig. 26; and

Fig. 33 is a transverse'sectional view of a printing drum including several holding means for attaching to the drum several printing forms in superimposed position.

Referring to the drawings, and more particularly to Fig;

- pins or other suitable aligning means engaging the cuti, the printing foil 1 is provided along one edge thereof with a portion of increased thickness which is shown to be produced by bending upon itself the edge portion of the printing foil 1.

As is best seen in Fig. 2, the edge portion 2 is first bent through an angle of 180 and then again bent through 180 to form a thickened edge portion having a shoulder 3 projecting from one side of the printing foil or sheet 1.

In the embodiment of Fig. 3, a strip Z' is glued to the printing foil 1, and thereupon the edge portion of the printing foil is bent upon itself to envelop the strip 2'. Thereby a thicker projecting shoulder 3 is formed on one side of the printing foil. V

In the embodiment shown in Fig. 4 a strip 2' glued to the edge portion of the printing foil 1 to form a projecting shoulder 3.

In the embodiment of Fig. 5 the edge portion 2 of the printing foil 1 is bent to form an accordion pleat having a projecting shoulder 3.

In the embodiment of the printing foil illustrated in Fig. 6, the main portion of the printing foil is provided with elongated cutouts or slots 4 which extend in a direction transverse to the direction of the edge 3 of the printing foil. As Fig. 7 shows, the elongated slots 4 are located in the main portion of the printing foil. In the embodiment illustrated in Fig. 7a, cutouts are provided in the thickened edge portion of the printing foil.

The cutouts 4 are provided in the printing foil for the purpose of engaging suitable pins or projections on the printing drum which engage the lateral edges of the cutouts 4. Due to the elongated shape of the cutouts 4, a slight adjustment of the printing foil in a direction transverse to the direction of the shoulder 3 is possible whereas lateral motions of the printing foil are prevented by outs 4. i

It will be understood that instead of slots in the thickened edge portions or in the main portion of the sheet, open cutouts may be provided along the outer-edge of the sheet and open on the outer edge of the sheet. By such cutouts an indented edge is formed along the sheet which permits the alignment of the sheet by suitable aligning means or members respectively engaging the open cutouts in the edge of the printing foil as will be described hereinafter.

Figs. 8 and 9 illustrate a printing drum of a duplicating machine according to the present invention. The printing drum 5 rotates about or with a shaft 6. In the cylindrical surface 7 of the printing drum 5 is provided a recess 8 extending in axial direction of the printing drum and having a recessed shoulder -8' engaging the projecting shoulder 3 of the printing foil which is provided with a thickened edge portion.

The printing foil 1 is superimposed upon the surface of the printing drum, and is subject to the pull exerted by inking rollers, moistening rollers, and even by the counter pressure roller by which the copy sheet is pressed against the printing foil. Due to the fact that the projecting shoulder 3 of the printing foil 1 engages the recessed shoulder 8' in the surface of the printing drum, a slipping of the printing foil is impossible.

In order to prevent the thickened edge portion of the printing foil from slipping out of the recess 8, holding means are provided for holding the edge portion of the printing foil in the recess 8.

The holding means include a holding portion located opposite the recess 8 and being a part of a lever having an arm 9 to which a spring 11 is connected. Due to the action of this spring 11 which is secured at the other end thereof to the printing drum, the lever 9 tends to turn into a position in which its holding portion engages the thickened edge portion of the printing foil andreliably holdsthe same in the recess 8. A handle lever 10a .is. connected to the shaft 10 to which the lever 9 is secured. I By; manual operation .of. the handle 1012, the

holding means can be turned against the action of the spring 11 into a position releasing the printing foil 1, and more particularly releasing the edge portion 2 of the printing foil. Such a release is necessary during insertion anism does not project beyond the surface of the printing.

drum. An interference of the holding means with the operation of the drum is prevented by the fact that the recess '8 is not provided directly in the surface of the printing drum, but in the recessed surface portion of the printing drum. Figs. 10 and 11 illustrate a modified embodiment of the present invention for holding on a printing drum a sheet of the type as illustrated in Fig. 6. Pins 13 are provided on the printing drum and project through perforations 4 in the printing foil 1. As described with reference to the embodiment of Figs. 8 and 9, a recess 8 is provided in a stepped recessed surface portion'of the printing drum 5. The thickened edge portion 2 of the printing foil 1 is arranged in the recess 8 with the projecting shoulder 3 engaging therecessed shoulder 8. As was explained with reference to Fig. 6, the pins 13, which constitute aligning means, are only provided for the purpose of preventing lateral movement of the printing foil in axial direction of the printing drum and permit slight adjustment of the printing foil in circumferential direction of the drum. The holding means is illustrated to be a lever 15 turnableabout a shaft 14, and urged by a spring 16 to engage the edge portion of the printing foil by a holding portion 15.

Figs. 12 and 13 illustrate a modified embodiment according to the present invention in which the printing foil 1 is secured at both ends thereof to the printing drum 5.

The thickened edge portion 2 of the printing foil engages with its projecting shoulder 3 the recessed shoulder 8 in the surface of the printing drum. Holding means 9 are shown to be a lever pivotable about a shaft 10 and urged by a spring 7 to press the thickened edge portion In order to permit a slight tensioning of the printing foil 1, the other edge portion of the printing foil is not positioned directly in a recess of the printing drum, but is located in a recess 20 provided in a movable member 18. The movable member-18 comprises a first element 18a having a recessed shoulder 26' and a second element 181) which is connected by screws to member 18a. A spring 19 is connected at one end thereof to member 18a and at the other end thereof to the printing drum to urge the member 18 to slide in a direction transverse to the axial direction of the printing drum. The thickened.

edge portion of the printing foil is located in the recess 26' formed by the members 18a and 18b and engages with its projecting shoulder 3' the recessed shoulder 20' in the movable member 18. Consequently, the spring 19 tensions the printing foil 1 by pulling its edge inwardly with respect to the printing drum. 7

Holding means are provided forholding the thickened edge portion of the printing foil in the recess 20, and

are illustrated to be a holding lever 21 turnable about a shaft 22 and being urged by the spring 23 into a position holding'the thickened edge portion of the printing foil in the recess 20. As can be clearly seen from Figs. 12

and 13, the recessed shoulders 8' and 20' are separated from each other at one side of the printing drum by a first surface portion of the printing drum on which the printing foil 1 is superimposed at the other-side of the pr t r m by a econd. s f c po t n .of. her int ns drum. The holding means 9 and 21 are located between the recesses 8 and 20 at the other side of the printing drum. Due to the fact that the spring 19 produces a slight tension in the printing foil 1, the formation of folds is prevented in the foil.

Fig. 14 illustrates another embodiment according to the present invention which is adapted for attaching two partly superimposed printing foils to the printing drum. The first printing foil 1 has again a thickened edge portion 2 located in a recess of the printing drum as described with reference to the other embodiments of the present invention. A holding means 24 is provided for holding the edge portion 2 of the first printing foil 1 in the recess 8. The holding means is pivotable about a shaft 25, and has a holding portion 24 which is formed with another recess 27 having a recessed shoulder 27. A spring 26 urges the holding portion 24 of the holding means to the illustrated position in which the first printing foil 1 is reliably retained in the recess 8. The second printing foil 29 has a thickened edge portion 28 forming a projecting shoulder on the second printing foil 29, such projecting shoulder engaging the recessed shoulder 27 in the holding portion 24 of the holding means. Another holding lever 31 is provided for holding the thickened portion 28 of the second printing foil 29 in the recess 27. A spring 33 urges the holding means 31 to turn about the shaft 32 and into the holding position illustrated in Fig. 14. The arrangement illustrated in Fig. 14 is capable of attaching to the printing drum two printing foils according to the present invention in superimposed position.

Fig. 15 is the illustration of a printing form foil 101 with one corner bent over. In this particular embodiment the projecting shoulders along the two opposite end edges are formed by two strips of material 103 formed to U-shape and attached adhesively to the edge of the foil.

Figs. 16 to are cross-sectional views illustrating different ways of providing a printing form foil with projecting shoulders along opposite edges. In all these figures the numeral 101 designates the actual printing form carrying reversed lettering for reproduction. In the case of very thin foils a reinforcement is provided in the form of an attached layer 102 of paper or in the form of a covering consisting of synthetic resin.

Numeral 103 designates edge reinforcements formed by U-shaped strips of material, while in the embodiments of Figs. 18 and 20 separate strips 104 are adhesively attached to the foil, said strips having a thickness in the range between .1 and .2 mm.

In the embodiment according to Fig. 19 the reinforcement 105 is obtained by repeated bending back upon itself the foil material and adhesively connecting the folds with each other.

In order to locate a printing form in a predetermined relative position in axial direction on the printing drum, the reinforced edge portion of the foil is provided with a set of cutouts, in this case elongated holes 106, as shown by Figs. 21 and 28, which cutouts are adapted to be engaged by corresponding pins of a clamping device described further below.

In the embodiment according to Figs. 23 and 24, the cutouts for location of the printing form in axial direction of the drum have the form of indentations 107 adapted to engage corresponding projections in a clamping device described below.

Fig. 25 illustrates the way in which a printing form foil is attached to a printing drum, the means for attachment or clamping being shown in section. The body of the drum 108 forms with an edge portion 109 a recessed shoulder 112 which engages the projecting shoulder of the printing form 101 on the lower side thereof. A holding means or clamping lever 110 is mounted for turning movement on the edge member 109 by means of an 'axle 113. The lever 110 is provided with a recessed shoulder 111 which engages the upper projecting shoulder of the printing form, the lever being urged into closing position by a spring 114. Since the printing form 101 abuts with its projecting shoulders formed by the U-shaped strip 103 against the 'two opposite recessed shoulders 111, 112, the form is held in its position and' in engagement with the above-mentioned shoulders by the tensile forces acting upon it in the operation of the printing device.

. Fig. 26 illustrates a similar arrangement of the holding means as shown in Fig. 25, however, in this case the rearward edge of the printing form is clamped by a second holding means or clamping lever which is acted upon by a spring:115.' A member 119 is arranged for sliding movement in a recess of the printing drum and is likewise provided with a recessed shoulder 112. A clamping lever 116 is mounted in the member 119 for turning movement about an axle 117 and is also provided with a recessed shoulder 111, a spring 118 urging the lever 116 into its closed position. The projecting shoulders of the U-shaped reinforcement of the printing form 101 engage the recessed shoulders 111 and 112 of the holding means similarly as described above. The edge portion of the foil is held by the springs in engagement with a holding means and at the same time the form 101 is held stretched and snugly against the cylindrical surface of the drum.

Fig. 27 illustrates holding means similar to those illustrated by Fig. 26, however in this case pins 120, 121 are additionally provided for locating the printing form in axial direction of the drum by means of mutual engagement of said pins with the cutouts of the printing form as illustrated by Figs. 21 and 22. If the printing form is placed into the clamping arrangement in correct position the pins will only lightly touch the lateral edges of the cutouts. If, however, the form is mislocated in axial direction of the drum, then the pins will engage the surface of the edge portion of the form between said cutouts so that the clamping levers cannot be moved into their proper closed position on account of the interference between the pins and the edge portions.

Fig. 28 illustrates a similar clamping arrangement including, however, additional insert strips 122 and 123 which are formed so as to conform to the edge portions of the printing form illustrated by Figs. 23 and 24. Also in this case the clamping levers cannot be closed unless the indentations of the printing form are properly lodged in relation to the corresponding projections of the strips 122 and 123, respectively, whereby correct position of the printing form is assured.

In Figs. 29 and 30 a printing form is shown in plan view and cross-section. In this case the two legs of the U-shape of the reinforcing strip 103 are of different length so that the projecting shoulders 123 and 124 are located at different distances from the outer edge of the printing form, in other words, the projecting shoulders on opposite sides of the printing form are offset against each other.

Fig. 31 shows a printing drum in transverse section and provided with attachment means, the shoulders 111 and 112 so located that they are adapted to properly engage a printing form according to Figs. 29 and 30.

Fig. 32 serves to show a clamping arrangement according to Fig. 26 in top view so as to make it clear that the clamping device extends in axial direction substantially over the whole width of the printing drum.

Fig. 33 shows a clamping arrangement specifically adapted for attaching both a printing form 101 and a second form or cover sheet 125 which may be used for covering certain portions of the printing form 101 which are not to be reproduced when the printing device is operated. In this case, like in the preceding examples, the member 109 constitutes with the edge of the drum 118 a recessed shoulder 112. A specially formed clamping lever 126 turnable around axle 113 is provided with the lever 126 into closed position. The reinforcement 103 of the printing form 101 abuts with its shoulders against the recessed shoulders 111 and 112. A second clamping lever 130 is mounted on the lever 126 for turnable movement about an axle 129 and is provided with a recessed shoulder 132, a spring 131 urging the lever 130 into closed position. of the second form or cover 125 abuts with'its projecting shoulders against the recessed shoulder 132 of the lever 130 and the recessed shoulder 127 of the lever 126, respectively. In this manner both the form 101 and the second form or cover 125 are safely attached'in proper position. i 1

For operating this clamping device one has to press first on the handle 133 of the lever 130 which thereupon opens and first releases the form or cover 125, Where after the projections 126a and 130a engage each other and cause the lever 126 to open so that now also the printing form 101 can be removed from the clampingdevice. In a similar manner, the clamping devices are opened for inserting the printing forms.

It should be noted that projecting shoulders along an edge of a printing from can be obtained also by attaching separate strips of material along said edge on both sides of the form and by enveloping said edge portion of increased thickness by a further strip shaped to U-form and attached to said reinforced edge portion so as to envelop the latter.

With the attachment means according to the invention it is possible to hold firmly even extremely .thin printing form foils, for instance only .07 mm. thick paper and only .04 mm. thick paper attached to .03 mm. metal foil, and to run safely a practically unlimited number of copies from such a form, for instance 25,000 pieces without trouble. This has been quite impossible with known attachment means based on holes or perforations in the foil itself. The advantageous effect of the attachment means according to the invention is also caused by the fact that the projecting shoulder of the reinforced edge portion extends uninterruptedly over the whole width of the form, i.e. in axial direction of the printing drum.

' Since the projecting shoulders are provided on both sides of the printing from in the case of certain embodiments of the invention, a particularly uniform pull is exerted on both sides of the printing form so that 'it is not possible that the reinforced portion might tend to tilt upwards which in extreme cases could possibly happen if there is only a shoulder on one side of the form; besides, the pull being exerted on two shoulders on opposite sides of the printing form, each of the two shoulders projecting on opposite sides of the edge portion of the printing form has to carry only one-half of the total tensile load so that tearing or separation of the reinforcing elements is safely prevented. In fact, the attachment means 'according to the invention are so efiicient that attaching a printing form foil only with one reinforced edge to the drum is suitable for many thousand cycles of operation.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of sheet attaching devices differing from the types described above.

While the invention has been illustrated and described as embodied in a sheet attaching device for holding on a printing drum a printing foil having at least one edge portion of increased thickness, it is not intended to be limited to the details shown, since various modifications and structural changes maybe made without departing in any way from the spirit of the present invention. V Without further analysis, the foregoing will so fully reveal the gist'of the present inventionthat others canby applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential charactcristics of the generic or specific aspects of this inven- The reinforcement 125a tionand, therefore, such adaptations should and are in tended to be comprehended within the meaning and rangeof equivalence. of the following claims.

-What is claimed as new and desired to be secured b Letters Patent. is:

tion of said printingdrum and defining a first recessed shoulder on the surface of the same; an elongated supporting member extending in axial direction of said printing drum and being mounted on the same for movement in a direction transverse to the axis of said printing drum, said supporting member being formed with an elongated recess defining a second recessed shoulder, said first and second recessed shoulders being separated from each other by a first surface portion of said printing drum on one'side ofsaid printing drum and by a second surface portion on the otherside of said printing drum; resilient means urging said supporting member to move in said transverse direction into a position in which said first and second recessed shoulders are farther spaced in circumferential direction of said printing drum with respect to saidifirst surface portion for tensioning a printing foil superimposed on said first surface portion of said print ing drum and having two projecting shoulders for respectively engaging said first and second recessed shoulders; two holding lever means mounted on said printing drum on said other side of said printing drum between said recesses, said two holding lever means having holding portions respectively located opposite said recesses in said printing drum and in said supporting member; and spring means engaging said two holding levers and urging the same into a position in which the respective hold ing portion of the same is located in the respective associated recess so as to slidably engage the printing foil of increased thickness defining oppositely projecting:

shoulders, one of said projecting shoulders engaging said recessed shoulder of said carrier member; and springloaded holding means secured to said carrier member and formed with a holding portion located opposite said supporting portion and with a second elongated recessed shoulder engaging the other one of said projecting shoulders, said holding means resiliently and slidably abutting said elongated edge-portion for holding said sheet in a position in which said projecting shoulders of the same are in engagement with said first and second recessed shoulders of said carrier member and of said holding means, respectively, and permitting sliding of said sheet into said position.

3. Printing foil attaching arrangement comprising, in combination, a printing drum having a surface formed with two axially extending and circumferentially spaced supporting portions and an elongated recess extending along each of said supporting portions, each of said recesses defining a recessed shoulder in said surface of said a printing drum; a printing foil superimposed on said surface of said printing drum and having two parallel edge portions of increased thickness, said edge portions defining elongated projecting shoulders on opposite sides of said printing foil, one of the projecting shoulders of each of said edge portions being at least partly located in one of said recesse's',-respectively, of said printing drum with said projecting shoulders engaging said recessed shoulders; and two spring-loaded holding means secured to said printing drum and having each a holding portion opposite said supporting portions and an elongated recess along the respective holding portion thereof, said elongated recesses of said holding means defining second recessed shoulders engaging respectively the other ones of the projecting shoulders of each of said edge portions of said printing foil on the other side thereof, said holding means resiliently and slidably abutting said edge portions for holding said edge portions in a position in which said projecting shoulders of said printing drum and of said holding means, respectively, are in engagement with said projecting shoulders of each of saidtwo parallel edge portions of said printing foil and permitting sliding of said foil into said position.

4., Printing foil attaching arrangement comprising, in combination, a printing drum having a surface including a surface portion formedwith at least one supporting portion and with one recess extending along said supporting portion and defining in said surface portion a recessed shoulder extending in axial direction; a thin flexible print ing foil superimposed on said surface of said printing drum and on said surface portion thereof and having at least one elongated edge portion of increased thickness defining projecting shoulders on opposite sides thereof, one of said projecting shoulders being at least partly located in said recess of said printing drum with one of said projecting shoulders engaging said recessed shoulder, said printing foil being formed with a set of cutouts passing through said edge portion and being spaced from each other along the length of the same in said axial direction, said cutouts extending transversely to said axial direction; a set of aligning members secured to said printing drum and projecting from the surface of the same, said aligning members being spaced from each other in axial direction of said printing drum and passing through said cutouts of said edge portions to secure said printing foil against movement in axial direction; and spring-loaded holding means secured to said printing drum and including a holding portion located opposite said supporting portion and being formed with .a recess extending along said holding portion and. resiliently and slidably engaging on the other side of said printing foil one of said shoulders projecting on said other side of said printing foil for holding said edge portion in a position in which said projecting shoulders of said printing foil are in engagement with said recessed shoulders of said printing drum and of said holding means and for permitting sliding of said foil into said position, while said cutouts are in substantial alignment with said aligning members.

5. Printing foil attaching arrangement comprising, in combination, a printing member having a surface formed. with at least one recess having a recessed shoulder transverse to said surface; a printing foil superimposed on said surface of said printing member and having at least one thicker edge portion defining at least one transversely projecting shoulder on at least one side of said printing foil, said thicker edge portion being at least partly located in said recess of said printing member with said projecting shoulder abutting said recessed shoulder; and holding means including a holding member mounted on said printing member for movement transverse to said printing foil and having a holding face slidably engaging said edge portion of said printing foil on the other side of said printing foil, and spring means on said printing member urging said holding member to move transversely with said holding face against said edge portion for holding said edge portion in said recess of said printing member while permitting sliding of said foil on said surface until said shoulders abut each other.

6. Printing foil attaching arrangement comprising, in combination, a printing member having a surface formed with at least one recess having a recessed shoulder transverse to said surface and a slide face adjacent said shoulder; a printing'foil superimposed on said surface of said printing member and having at least one thicker edge portion defining at least one transversely projecting shoulder on at least one side of said printing foil and another slide face adjacent said projecting shoulder, said thicker edge portion being at least partly located in said recess of said printing member with said projecting shoulder abutting said recessed shoulder and with said slide faces slidably engaging each other; and holding means ineluding a holding member mounted on said printing member for movement transverse to said printing foil and to said slide faces and having a holding face slidably engaging said edge portion of said printing foil on the other side of said printing foil, and spring means on said printing member urging s'aid holding member to move transversely with said holding face against said edge portion for holding said edge portion in said recess of said printing member while permitting sliding of said foil on said surface until said shoulders abut each other.

7. Printing foil attaching arrangement comprising, in combination, a printing member having a surface formed with at least one recess having a recessed shoulder transverse to said surface and a slide face adjacent said shoulder; a printing foil superimposed on said surface of said printing member and having at least one thicker edge portion defining at least one transversely projecting shoulder on at least one side of said printing foil, said thicker edge portion being at least partly located in said recess of said printing member with said projecting shoulder abutting said recessed shoulder; and holding means including a holding member mounted on said printing member for turning movement about an axis parallel to said shoulders, said holding member having a portion moving transverse to said printing'foil and having a holding face slidably engaging said edge portion of said printing foil on the other side of said printing foil, and spring means on said printing member urging said holding member to move transversely with said holding face against said edge portion for holding said edge portion in said recess of said printing member while permitting sliding of said foil on said surface until said shoulders abut each other.

References Cited in the file of this patent UNITED STATES PATENTS 830,969 Carter Sept. 11, 1906 890,759 Dick June 16, 1908 1,215,344 Clark Feb. 13, 1917 1,247,308 Meuser Nov. 20, 1917 1,480,489 Benzett Jan. 8, 1924 1,667,284 Shea Mar. 13, 1928 1,686,065 Blaine Oct. 2, 1928 1,788,662 Creed Jan. 13, 1931 1,827,300 Pritchard et al Oct. 13, 1931 2,031,559 Daminaitis Feb. 18, 1936 2,051,858 Huck et al. Aug. 25, 1936 2,194,560 Marchev et al. Mar. 26, 1940 2,204,935 Kampczyk June 18, 1940 2,218,451 Heyne Oct. 15, 1940 2,231,291 Morrison Feb. 11, 1941 2,249,938 Bromberger et a1 July 22, 1941 2,296,533 Neal Sept. 22, 1942 2,381,461 Morse Aug. 7, 1945 2,512,940 Janke June 27, 1950 2,541,254 Huck et al. Feb. 13, 1951 2,681,007 Harless June 15, 1954 2,689,521 Ritzerfeld et a1 Sept. 21, 1954 2,704,028 'Bruns et al. Mar. 15, 1955 2,764,936 Johnson et al. Oct. 2, 1956 2,822,754 Huck Feb. 11, 1958 will

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