US 3883940 A
An apparatus for fastening a holding bar on a printing blanket is disclosed, the holding bar having a bight and a pair of diverging legs extending outwardly from opposite ends of the bight. The apparatus comprises an anvil, hammer means, fastening means comprising a cutout in the anvil defining a first clamping surface and a clamping member moveable toward and away from the cutout and having a second clamping surface, the surfaces being adapted to engage and clamp the holding bar. A positioning means is provided for positioning and holding the blanket against the bight during deformation of a leg of the holding bar by the cooperating hammer-anvil means.
Claims available in
Description (OCR text may contain errors)
United States Patent Wagner 1 1 May 20, 1975 1 APPARATUS FOR FASTENING A HOLDING 3,520,046 7/1970 Erhardt, Jr. et al. 29/243.58 X 3,675,573 7 1972 Hawks 101/41s.1
BAR ON A PRINTING BLANKET 3,706,121 12/1972 Gillespie 29/243.58 x
 Inventor: William T. Wagner, Dayton, Ohio Assignee: Dayco Corporation, Dayton, Ohio Filed: July I], 1974 Appl. No.: 487,509
Related US. Application Data  Division of Ser. No. 349,345, April 9, 1973.
References Cited UNITED STATES PATENTS 10/1949 Bell ..29/243.57
6/1953 Bindszus ..29/243.58
4/1956 Bruggmann 29/243.58
Primary Examiner-Richard .l. Herbst Assistant ExaminerVictor A. DiPalma 57 ABSTRACT An apparatus for fastening a holding bar on a printing blanket is disclosed, the holding bar having a bight and a pair of diverging legs extending outwardly from opposite ends of the bight. The apparatus comprises an anvil, hammer means, fastening means comprising a cutout in the anvil defining a first clamping surface and a clamping member moveable toward and away from the cutout and having a second clamping surface, the surfaces being adapted to engage and clamp the holding bar. A positioning means is provided for positioning and holding the blanket against the bight during deformation of a leg of the holding bar by the cooperating hammer-anvil means.
6 Claims, 8 Drawing Figures PATENTEnuAYzoms 3. 883.940
sum 10F 2 PATENTEB HAY 2 0 I975 SHEET 2 BF 2 1 APPARATUS FOR FASTENING A HOLDING BAR ON A PRINTING BLANKET This is a division, of application Ser. No. 349.345, filed Apr. 9, I973.
BACKGROUND OF THE INVENTION There are numerous printing presses in current use which employ what are commonly referred to in the art as printing blankets and these printing blankets are usually comprised of a plurality of bonded layers of fabric coated with an outside layer of rubber-like material. The rubber-like material is used to pick up an ink design or image deposited thereon and transfer such design or image onto another object.
Many of the printing blankets in current use employ holding devices or bars for holding such blankets on associated cylindrical rollers, or the like. However, such holding bars are either very complicated and expensive or can only be installed in position using comparatively expensive apparatus and methods.
SUMMARY This invention provides a simple and economical holding bar for a printing blanket and a printing blanket assembly having a pair of such holding bars at its opposite ends as well as an apparatus for and method of installing such holding bars on the printing blanket. The holding bar comprises a channel-like member having a bight and a pair of legs diverging outwardly from opposite ends of the bight with at least one of the legs having a plurality of improved tooth-like projections extending therefrom toward the other of the legs; and, the holding bar is such that it may be fixed in position on its associated printing blanket free of additional adhesive means, or the like.
Other details, uses, and advantages of this invention will be readily apparent from the embodiments thereof presented in the following specification, claims, and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings show present preferred embodiments of this invention, in which FIG. 1 is a view with parts in elevation, parts in cross section. and parts broken away of an exemplary blanket assembly of this invention which employs one embodiment of an improved holding bar of this invention at opposite ends thereof;
FIG. 2 is a fragmentary perspective view of the holding bar used at opposite ends of the blanket of FIG. 1;
FIG. 3 is a fragmentary view looking from the open end of the channel-like holding bar perpendicularly toward the bight of such bar;
FIG. 4 is a fragmentary view taken on the line 4-4 of FIG. 3;
FIG. 5 is an end view illustrating another exemplary embodiment of a holding bar of this invention;
FIG. 6 is a view similar to FIG. 2 illustrating another exemplary embodiment of a holding bar of this invention;
FIG. 7'is a view similar to FIG. 3 of the holding bar of FIG. 6', and
FIG. 8 is a side view in elevation with certain parts broken away and other parts shown schematically of one exemplary embodiment of an apparatus and method of this invention which is employed to install holding bars on associated printing blankets.
DETAILED DESCRIPTION Reference is now made to FIG. 1 of the drawings which illustrates one exemplary embodiment of a printing blanket assembly of this invention which is designated generally by the reference numeral 20. The blanket assembly 20 has a central blanket portion or blanket 21 which is comprised of a plurality of three layers of woven material each designated by the same refer ence numeral 22 and the layers 22 are suitably bonded together in accordance with techniques which are known in the art and serve as supporting means for an ink-transferring layer 23 which is suitably bonded to the top layer 22. The ink-transferring layer 23 is used in accordance with techniques known in the art to pick up an ink design or image and transfer such design or image onto another article. The blanket assembly 20 has a pair of blanket holding devices 24 which will be referred to hereinafter as holding bars 24 and such bars are fixed in position at opposite ends thereof. The construction and arrangement of the holding bars 24 is such that they may be fixed in position in a highstrength manner free of additional adhesive or bonding means between the blanket 21 and the holding bars 24 whereby such holding bars 24 are used to hold the blanket 20 in position concentrically around an associated printing cylinder (not shown) of known construction in a high-strength manner.
Each of the woven layers 22 may be made of any suitable material such as a woven fabric and the fabric may be a so-called square woven fabric having warps and wefts arranged at to each other or may be a bias woven fabric having warps and wefts at an angle other than 90 to each other. Further, the layer 23 may be made of any suitable elastomeric material capable of transferring ink, such as, a natural or synthetic rubber compound or a suitable plastic material.
Having described the blanket assembly 20, the detailed description will now proceed with the description of one exemplary embodiment of the holding bar of this invention and which is provided at each end of the blanket assembly 20 and for this description reference is made to FIGS. 24 of the drawings. The holding bar 24 is in the form of a channel-like member having a bight 30 and a pair of legs 31 and 32 diverging outwardly from opposite ends of the bight. The leg 31 has a plurality of tooth-like projections 33 extending therefrom toward the other leg 32 and a plurality of inspection apertures 34 in each leg 31 and 32.
The apertures 34 in each leg 31 and 32 respectively are arranged in spaced relation and each aperture in each leg, either 31 or 32, is arranged in substantially axially aligned relation with an associated aperture in the other leg. The inspection apertures 34 enable inspection of the blanket 21 to assure positioning of an edge portion 35 of such blanket, see FIG. 1, closely adjacent the bight 30 and preferably against the inside surface of such bight.
The channel-like member or holding bar 24 is adapted to be deformed so that the legs 31 and 32 thereof are arranged substantially parallel as illustrated in FIG. 1 with the projections 33 piercing the blanket to hold the bar 24 firmly in position.
Each projection 33 is in the form of a tab which will also be referred to as tab 33 and is hinged or hingedly fastened to leg 31 along an edge 36 and each tab extends transverse its original position in the leg 31 to define a corresponding opening in such leg. In this example each tab 33 extends substantially perpendicular to its leg 31 and has a V-shaped configuration provided with a sharp apex 40 and such V-shaped configuration defines a corresponding opening 37 in the leg 31 with the opening having a substantially triangular peripheral outline. The sharp apex 40 and the V-shaped or sawtoothed configuration ofeach tab 33 enables the tab to pierce completely through the blanket 21 and in particular pierce completely through the three fabric layers 27 and partially within the clastomeric layer 23 as illustrated at 41 in FIG. 1.
Although the tabs 33 of this example are shown as V- shaped it will be appreciated that each projection or tab 33 may have any suitable configuration or peripheral outline including trapezoidal, semi-circular, etc.
The holding bar 24 may be made by roll forming, extrusion, or other suitable process and the tabs 33 are preferably made by lancing or stab punching in accordance with techniques which are known in the art whereby a punching die is urged against the outside surface of the leg 31 and cooperates with a cooperating die to define the tabs 33 and associated openings 37 either individually or a plurality thereof in a simultaneous manner. In applications where the holding bar 24 is made by forming a flat strip of material, the tabs 33 are preferably defined while the strip is in a substantially flat configuration.
The legs 31 and 32 of the holding bar 24 may be of equal thickness, as in this example, or such legs may have unequal thicknesses. In addition, the leg 31 has a flange-like outer portion or flanged portion 42 which extends transverse, i.e., perpendicular in this instance, to the main portion of the leg 31. The flanged portion 42 in particularly adapted to be used in holding the holding bar 24 and hence its blanket assembly 20 in position on an associated cylinder.
As seen in FIGS. 2 and 4 of the drawings, the tabs 33 are arranged in a plurality of two rows which are arranged parallel to the bight 30 and each tab 30 in one row is arranged on a line with the closest tab in the other row with such line extending perpendicular to the bight 30. Nevertheless, it will be appreciated that the tabs 30 need not necessarily be arranged in the particular arrangement illustrated in FIG. 2 but may be arranged in a plurality of rows so that each tab in one particular row would be staggered or arranged out of alignment with an associated tab in the adjacent row. Stated otherwise, each tab 30 in one of two rows may be arranged on a line with the closest tab in the other row with such line being at an angle other than ninety degrees with the bight.
Other exemplary embodiments of holding bars of this invention are illustrated in FIGS. 5 and 67. The holding bars illustrated in FIGS. 5 and 6-7 are similar to the holding bar 24; therefore, such holding bars will be designated by the reference numerals 24A and 24B respectively and representative parts of each holding bar which are similar to corresponding parts of the holding bar 24 will be designated in the drawings by the same reference numeral as in the holding bar 24 (whether or not such components are mentioned in the specification) followed by an associated letter designation either A or B and not described again in detail. Only these component parts of each holding bar which are substantially different from corresponding parts of the holding bar 24 will be designated by a new reference numeral also followed by the associated letter designation and described in detail.
The holding bar 24A has a bight 30A and a pair of outwardly extending diverging legs 31A and 32A with the leg 31A having a flanged portion 42A, The holding bar 24A has spaced inspection openings 34A therein and has tabs 33A of substantially saw-toothed or V- shaped configuration extending from leg 31A toward leg 32A and defining corresponding roughly triangular openings 37A in leg 31A.
in addition, the holding bar 24A has a plurality of V- shaped tabs 43A which are similar to tabs 33A and extend from the leg 32A toward the leg 31A. The tabs 43A are preferably made in a similar manner as the tabs 33A by stab punching, or the like, whereby simultaneously with the forming of each tab 43A a corresponding roughly triangular opening 44A is defined in the leg 32A.
The tabs 33A are arranged in a rectilinear row which is parallel to bight 30A. Similarly, the tabs 43A are arranged in a row which is parallel to the bight 30A. The rows of tabs 33A and 43A are arranged so that once leg 32A of holding bar 24A is urged toward leg 31A to clamp the holding bar 24A in position on an associated blanket the tabs 33A and 43A will not strike each other. In this example, the tabs 43A extending from the leg 32A are positioned closer to the center of the associated printing blanket than the tabs 33A extending from leg 31A.
Although only a single row of tabs has been shown in each leg of the holding bar 24A, it will be appreciated that each leg may have a plurality of rows of tabs provided therein or tabs provided in geometric patterns other than rows. In each instance, however, the tabs are suitably positioned so that once the legs are deformed against the end portion of an associated blanket the tabs in the two legs will not interfere with each other.
The holding bar 248 illustrated in F165. 67 also has a bight 30B and a pair of legs 31B and 32B diverging outwardly from opposite ends of the bight with the leg 318 having a plurality of tooth-like projections or tabs 33B extending therefrom toward the oppositely arranged leg 32B. The holding bar 248 also has a plurality of inspection openings 345 provided therein in spaced relation along each of its legs 31B and 32B and for the same purpose as the inspection openings 34 provided in the holding bar 24.
The holding bar 248 is preferably made by extrusion process wherein the channel-like configuration is defined together with elongated rib-like structures which are then suitably machined or cut using techniques which are known in the art to define the projections 338. The projections 33B of this example are machined so that they have approximately rectangular apexes 408, which to illustrate the character thereof are shown having exaggerated size areas, and with each projection 333 having machined side edges designated by the reference numerals 45B.
The projections 338 in this example are shown arranged in a plurality of two rows and having substantially rectangular apex portions 408; however, it will be appreciated that any suitable number of rows or nonrectilinear geometric pattern of tabs may be provided and the cutting or machining may be achieved so as to define tabs having V-shaped outlines and sharp points in a similar manner as the tabs 33 of the holding bar 24.
The holding bar 248 may be made of any suitable material including metallic and non-metallic materials and preferably by extrusion process; and, if desired projections similar to projections 338 may also be defined in the leg 32B in a similar manner as the projections comprising leg 318.
The holding bars 24A and 248 may be installed on associated blankets 21 in a similar manner as the holding bar 24. In each instance the associated projections of a particular holding bar would assure that its holding bar could be fixed to a printing blanket in a highstrength manner yet free of, i.e., without adhesive means between the holding bar and blanket.
Each holding bar 24, 24A, and 248 has been described herein as being held in position free of adhesive means between the bar and its associated printing blanket. However, it will be appreciated that such adhesive means may be employed, if desired.
Having described several exemplary embodiments of the improved holding bar of this invention and a blanket assembly which utilizes one embodiment of such a holding bar, the detailed description will now proceed with a description of an exemplary apparatus and method of this invention which may be used for fastening a holding bar on a printing blanket and for this description reference is now made to FIG. 8 of the drawing. The apparatus and method illustrated in FIG. 8 is designated generally by the reference numeral 50 and will be described in connection with the installation of a holding bar 24 on an associated printing blanket 21; however, such apparatus and method may be utilized to install holding bar 24A, 248, or other holding bars on associated printing blankets.
The apparatus 50 comprises a supporting structure including a worktable 51 which is suitably supported on a floor, or the like, by a plurality of upstanding columns 53 and associated bracing members 54 which may have different configurations. The apparatus 50 has a pair of its columns at one end thereof which are each provided with an upper portion 55 which extends above the worktable 51 and each portion 55 has a cutout therein defining a U-shaped support 56. Each support 56 rotatably supports an associated end ofa central shaft 57 of a supply roll 60 of blanket material which for convenience and easy correlation with the blanket assembly will also be designated by the reference numeral 21.
The material 21 may be unwound as illustrated at 61 and cut at a cutting station 62 to define a plurality of blankets 21 each having a predetermined length and each cut blanket length 21 has a pair of holding bars 24 installed at opposite ends thereof utilizing the apparatus and method 50 of this invention to define a blanket assembly 20.
The apparatus 50 has a clamp bar 63 at the cutting station 62 which is movable toward and away from the work-table 51 by an actuating mechanism which is suitably attached thereto and is designated schematically by a double arrow 64; and, the actuating mechanism 64 may be of any suitable construction known in the art and hence need not be described in detail. The worktable 5] has a knife-receiving slot 65 provided therein and blanket material 21 is unwound from the supply roll 60 until a desired length thereof extends leftwardly of the knife receiving slot 65. The clamp bar 63, which during this unwinding of blanket material 21 is in a raised position, is then lowered into clamping engagement against the material 21 utilizing the actuating mechanism 64 whereupon a knife 66 is moved into cutting engagement against the blanket material and so that the knife 66 extends through the slot 65 to provide simple and easy cutting of the blanket material 21. The knife 66 may be operated manually or may be operated automatically, as herein, using a device 67 which is shown schematically by a fragmented block and device 67 operates to extend and retract the knife 66 as well as traverse such knife across the worktable 51 in a direction perpendicular to the plane of the paper.
Once the desired length of blanket material has been cut to define a blanket 21, the holding bars 24 are suitably fixed into position at opposite ends thereof. However, the following is a description of installing bar 24 at only one end of the blanket 21 with it being under' stood that the holding bar 24 at the opposite end may be installed in a similar manner.
For the purpose of fixing each holding bar firmly against its blanket the apparatus 50 has an anvil 70 which is suitably supported on the worktable 51 and hammer means in the form of a hammer block 71 which, for simplicity, will be referred to hereinafter simply as hammer 71, is provided and supported for movement toward and away from the anvil 70 utilizing any suitable mechanism known in the art and such mechanism is indicated schematically by the double arrow 72. For example, the hammer 71 may comprise a portion of a conventional press (not shown) and may be moved toward and away from the worktable 51 and hence anvil 70 by such press.
The apparatus 50 has fastening means indicated generally at 73 for detachably fastening an associated holding bar 24 to the anvil 70 and such fastening means comprises a cutout in the anvil 70 with the cutout defining a horizontal supporting surface 75 and a vertical clamping surface 76. The fastening means 73 includes a clamping member which is movable toward and away from the clamping surface 76 and the clamping member 80 has a cooperating clamping surface 81. The clamping surfaces 76 and 81 are adapted to respectively engage the outside surface of the bight 30 and the terminal end of one of the legs of the clamping member 24, and in the case of holding bar 24 the terminal end or outside surface of the flange portion 42, to thereby clamp the holding bar 24 against the anvil and enable a terminal end portion of the blanket 21 to be urged between the diverging legs 31 and 32 of the clamping member 24 and against the inside surface of the bight 30.
The apparatus 50 also has a hold-down member 83 which may be provided with a blanket engaging material 84 made of an elastomeric material and the holddown member 83 holds the blanket 21 firmly within bar 24 to enable the leg 32 thereof to be engaged by the hammer 71 and the holding bar 24 deformed generally by bending in the area where the leg 32 adjoins bight 30 so that the legs 31 and 32 are arranged in substantially parallel relation and with the tabs or projections 33 piercing the blanket 21 to fix the holding bar 24 firmly against the blanket 21.
This deformation of the holding bar 24 is achieved as the hammer 71 is moved by its actuating mechanism 72 and the tabs 33 pierce through the three fabric layers 22 comprising blanket 21 and such tabs 33 enter the elastomeric layer 23, see the attached holding bars illustrated in FIG. 1. Thus, a high-strength mechanical connection is provided which assures that the holding bar 24 is fixed firmly in position without the need for additional adhesive means or other bonding materials between the holding bar 24 and the blanket 21.
To assure that the hammer 71 engages the holding bar 24 in an efficient manner, the hammer 71 has guide means in the form of a guide projection 85 and such guide projection 85 is adapted to be received in cooperating guide means or a guide slot 86 provided in the anvil 70. The guide means 85 and 86 serve to confine the hammer 71 so that its movement is substantially vertical thereby assuring that once the hammer 71 engages the leg 32 of the holding bar 24 the force applied against such leg is a substantially vertical force without sliding movement between the hammer 71 and the holding bar 24 which might tend to distort the legs from their optimum clamping positions.
The fastening means 73 also includes means for moving the clamping member 80 toward and away from the anvil 70 and such moving means comprises a threaded member 90 having a head portion 91 which engages the clamping member 80 and the threaded member 90 extends through aligned bores 92 and 93 in member 80 and anvil 70 respectively. A threaded nut, which may be in the form of a wing nut 94 is provided and is threadedly engaged on the outer end of the threaded member 90 and has an inside surface which engages the anvil 70 so that upon threading the wing nut 94 toward the head 91 of bolt 90 the clamping member 80 is pulled toward the anvil 70 to clamp the holding bar 24 firmly against the anvil. Upon loosening the wing nut 94 the clamping member 80 and the threaded bolt 90 are free to be moved away from the anvil 70 manually or using any suitable means. The anvil 70 is detachably fixed to the worktable 51 by a plurality of threaded screws 95 each of which extends through an associated opening 96 in the worktable 51 and is threadedly received within a cooperating threaded opening 97 in the anvil 70.
In the above description a wing nut 94 and a threaded bolt 90 have been described holding the clamping member 80 in position. However, it will be appreciated that a plurality of such components may be utilized and provided in spaced relation along member 80 as it extends across the worktable 51.
The apparatus 50 has positioning means designated generally by the reference numeral 100 and such positioning means comprises a slidable block 101 which is suitably slidably supported on the worktable 51 for sliding movement toward and away from the anvil 70 and means for moving the block 101 toward and away from the anvil 21. The block 101 serves as a back-up block for the hold-down member 83. The positioning means 100 also includes a block positioning device 102 which includes a support 103 which is suitably fixed to the work-table 51 and supports a shaft 104 for free rotation either clockwise or counterclockwise while preventing axial movement of shaft 104. The shaft 104 has a knurled knob 106 fixed to one end thereof for rotating the shaft 104 and a threaded opposite end portion 107 which is threadedly received within a threaded opening 108 in the block 101. Thus, upon rotating the shaft 104 in one direction the block 101 is moved toward the anvil 70 and upon rotating the shaft 104 in an opposite direction the block is moved away from such anvil. In particular, once it is desired to move a blanket 21 toward the anvil 70 which has a holding bar 24 suitably temporarily fastened thereto by fastening means 73,
the hold-down member 83 is urged against the top surface of the blanket 21 so that it compresses the blanket 21 between thhe backup block 101 and the hold-down member 83. The knob 106 may then be rotated, as desired, to move the block 101 and blanket 21 held thereagainst toward or away from the holding bar 24 and thereby precisely position the edge of the blanket 21 against the inside surface of the bight of such holding bar.
In the above description the positioning means 100 has been described employing shaft 104 and associated components; however, it will be appreciated that a plurality of shafts 104 and associated components may be provided along the backup block 101 at spaced locations.
Having described the apparatus 50 in detail a detailed description will now proceed with the simple method of this invention which is used to fix a holding bar 24 first at one end of a blanket 21 and then at its opposite end.
A printing blanket 21 having the desired length may be cut at the cutting station 62 of the apparatus 50 or the blanket may be cut using any suitable apparatus or technique.
The holding bar 24 having a bight and a pair of diverging legs extending outwardly from opposite ends of the bight is fastened to the anvil by suitably clamping the outside surface of the bight and the terminal end of its leg 31 between cooperating clamping surfaces of the clamping member and anvil 70. Once this is achieved it will be seen that the leg 32 extends upwardly in the manner illustrated at 110 and is adapted to receive an end portion of the blanket 21 therewithin.
The blanket is positioned roughly with an end portion thereof between legs 31 and 32 whereupon the blanket is then clamped or sandwiched between hold-down member 83 and backup block 101 of the blanket positioning means 100. The terminal end edge of the blanket is then precisely positioned or adjusted against the inside surface of the bight 30 of the holding bar 24 by suitably rotating the knurled knob 106 and the shaft 104 fixed thereto. To assure that the end edge 35 of the blanket 21 is against the bight 30, inspection is provided visually or by suitable automatic means utilizing the inspection apertures 34.
Once the blanket 21 is properly positioned within the holding bar 24, the hammer 71 is moved by its moving means 72 toward the anvil 70 so that it engages the upwardly extending leg 32 and deforms the holding bar 24. As the hammer 71 is urged toward the anvil 70 the guide means 85 and 86 assures that the movement of the hammer is substantially free of horizontal sliding movements between the hammer 71 and the holding bar 24. As the hammer 71 homes into position the tabs 33 are forced through fabric layers 22 in the manner illustrated in FIG. 1 to firmly fix the holding bar 24 to the end of the blanket 21 and this fixing action is achieved without requiring adhesive means or other bonding materials.
The hammer 71 and hold-down member 83 are then retracted and the fastening means 73 is operated to unfasten the holding bar 24 whereupon the blanket 21 with one holding bar 24 fixed thereto is removed and the blanket rotated and the operation repeated at the opposite end so that such blanket has holding bars 24 at opposite ends thereof to define the blanket assembly illustrated in FIG. 1.
In this disclosure of the invention the anvil 70 is shown as being provided with a cutout which is adapted to receive an associated holding bar such as the holding bar 24 which has the previously defined projections or tabs 33 therein; however, it will be appreciated that it may be desirable in some applications of this invention, depending upon the materials employed, to provide a modified anvil 70 which has suitable tooling provided as an integral part thereof so that as the hammer 71 is brought into engagement with the anvil 70 the tooling provided on the anvil 70 forms or defines the tabs 33 simultaneously with the action of the hammer 71 in deforming the holding bar 24 to clamp it into position against an associated end portion of a blanket 21.
Each of the holding bars 24, 24A, and 24B of this invention may be made of any suitable material. Preferably each holding bar is made of a metallic material such as steel or aluminum, for example, or each holding bar may be made of a plastic material having suitable properties.
While present exemplary embodiments of this invention, and methods of practicing the same, have been illustrated and described, it will be recognized that this invention may be otherwise variously embodied and practiced within the scope of the following claims.
What is claimed is:
1. An apparatus for fastening a holding bar on a printing blanket; said holding bar having a bight and a pair of diverging legs extending outwardly from opposite ends of said bight; said apparatus comprising; an anvil; hammer means; fastening means for detachably fastening said holding bar to said anvil; said fastening means comprising, a cutout in said anvil defining a clamping surface, a clamping member which is movable toward and away from said cutout and having a cooperating clamping surface, said clamping surfaces being adapted to engage the outside surface of said bight and the terminal end of one of said legs respectively to clamp said holding bar against said anvil and thus enable a terminal end of said blanket to be urged between said diverging legs and against said bight; and positioning means for positioning and holding said blanket to enable said other leg to be engaged by said hammer means to deform said leg so that said legs are arranged substantially parallel with said projections piercing said blanket to fix said holding bar firmly in position.
2. An apparatus as set forth in claim 1 in which said anvil has guide means and said hammer means has cooperating guide means, said guide means serving to guide said hammer means as it is urged against said anvil.
3. An apparatus as set forth in claim 1 in which said fastening means comprises means for moving said clamping member toward and away from said anvil.
4. An apparatus as set forth in claim 3 in which said moving means comprises a threaded member having a head portion engaging said clamping member and extending through a cooperating bore in said anvil and a threaded nut threadedly engaged on said threaded member and engaging said anvil to pull said clamping member toward said anvil.
5. An apparatus as set forth in claim 1 in which said positioning means comprises a hold-down member and a back-up block which are movable in a precise manner with said blanket clamped therebetween to thereby enable precise positioning of said terminal end of said blanket between said diverging legs and against said bight.
6. An apparatus as set forth in claim 1 and further comprising means supporting a roll of blanket material for unwinding rotation and means for cutting said blanket material to define said printing blanket.