Patent Application
20070277583
The hold-down device 10 for securing a graphic arts die plate to a press chase includes a main body unit 12 and a fastener 14. Device 10 is adapted to be inserted in a cavity 16 of a graphic arts press chase 18. As depicted in
A fulcrum component 36 that is of T-shaped cross-sectional configuration is interposed between the anchor members 20 and 22 of main body unit 12. Viewing
The lower margins 34 of anchor members 20 and 22 are stepped back from the faces 24 of anchor members 20 and 22 and are provided with semi-circular, aligned recesses 37 that receive a circular spring steel lock ring 48. Opposed ends 50 of lock ring 48 are spaced from one another whereby ring 48 biases the ends 34 of anchor members 20 and 22 toward one another.
Fulcrum component 36 is provided with an elongated, threaded, internal central passage 52 extending through the head segment 38a and post segment 40 of the fulcrum component 36. Fastener 14 preferably comprises a socket button head screw 56. The passage 52 in component 36 is adapted to complementally receive the threaded stem portion 54 of the socket button head screw 56 that has a head portion 58 provided with a central, transversely polygonal socket 60.
Apertured chases forming a part of flat bed and rotary graphic arts presses especially adapted for substrate processing operations that include hot foil stamping, embossing, or combinations thereof, are conventionally provided with a series of spaced, generally cylindrical cavities 16, as schematically shown in
The upper ends 32 of anchor members 20 and 22 are provided with outwardly-facing notches 68 that are open at the upper surfaces of ends 32, and have innermost, outwardly directed ledge portions 68a. It is preferred that the faces 70 of ends 32 of anchor members 20 and 22 be inclined inwardly as shown in
In operation, the main body unit 12 minus socket button head screw 14 is inserted in a cavity 16 by the user grasping the ends 32 of anchor members 20 and 22 between two fingers and exerting a compressive force to move the ends 32 toward one another against the bias of spring steel lock ring 48 as the anchor members 20 and 22 pivot about the fulcrum section 38 of fulcrum component 36. After the main body unit 12 is partially inserted in the cavity 16 as shown in
Although it is contemplated that the individual hold-down devices 10 will be permanently installed in respective cavities 16 in either a flat chase or a rotary chase, in the event the press operator desires to remove a particular hold-down device 10 for any reason, including relocation of the device, each hold-down device may be readily removed from its cavity. Removal is accomplished by inserting the legs of a bifurcated pincer tool having inwardly directed jaws on the lower extremities thereof, into the notches 68. Application of compressive force on the legs of the removal tool causes the jaws to grip the ledge portions 68a within notches 68 of anchor members 20 and 22 and to rotate the upper ends 32 thereof toward one another, against the bias of lock ring 48, to an extent causing the ends 32 to clear the shoulder 66 so that the device 10 can then be readily removed from the cavity 16. The device 10 that has been removed from a cavity can either be placed in another cavity, or returned to the cavity from which it was initially removed.
The distance from the outermost design-defining surface 76 of die 74 to the outermost face of plate 72 may typically be about 0.19 in. The thickness of the head portion 58 of a preferred socket button head screw 14 is about 0.108 in. Using a washer 78 having a thickness of about 0.04 in., the total height of washer 78 and head 58 will equal about 0.148 in., which is less than the 0.19 in. thickness of die 74, thus assuring that the button head 58 of screw 14 does not interfere with the design image of die 74.
The press operator generally furnishes an artwork image film to the die supplier that is then used by the supplier to prepare dies having die surfaces that correspond to respective images on the master film. The die supplier is then required to prepare dies that have die images that match the artwork images on the film master. Because the die images must register with the artwork images on a substrate passed through the press, it is necessary that the dies be in precise registration with respective artwork images.
Hold-down devices 10 can advantageously be used to secure either a single die to a flatbed chase or a rotary chase, or a support plate that carries a plurality of dies. If the job calls for a number of individual dies to be directly secured to a chase with the die surfaces in alignment with images on a substrate processed by a press, X-Y coordinate data with respect to the location of the cavities of the specific chase may be used to establish where holes are to be drilled in each die for receipt of a respective screw 56 that is to be threaded into a corresponding hold-down device 10. If the die supplier has appropriate X-Y coordinate data available with respect to the location of cavities in the chase to be used by the press operator, or the die supplier can prepare an X-Y coordinate table from known relative locations of the chase cavities, that coordinate data may be used to establish where at least two spaced holes are to be drilled, and then proceed to drill the requisite holes, in each individual die or die support plate. The die image will then relatively precisely align with a respective artwork image when the die is mounted on the chase using screws passing through respective holes and threaded into hold-down main body units in specified cavities. In the event the die supplier does not have information with respect to the location of cavities in a particular chase, the hole locations necessary to generate X-Y coordinate data can be obtained from the press operator. This data is then used to locate the relative position of holes to be drilled in the dies.
In the case where a plurality of dies are to be mounted in predetermined disposition on a die support plate, preferred structure for securing multiple dies to a single support plate is disclosed in the assignee's application Ser. No. 11/109,605, filed Apr. 20, 2005, entitled Graphic Arts Die and Support Plate Assembly, now U.S. Pat. No. ______, which is incorporated herein by specific reference thereto. In accordance with that invention, a die support plate 72 is provided that mounts a series of design-defining dies 74. The support plate with a plurality of dies thereon is adapted to be placed over the chase 18, preferably in a predetermined disposition with respect to those cavities 16 of the chase that are to be provided with hold-down devices 10 as determined by the X-Y coordinate matrix of the chase cavities. The die support plate 72 has X-Y coordinate-derived pre-drilled holes 80 for receipt of the stem portion 54 of a respective socket button head screw 56. It is to be understood in this respect that the holes drilled in the die support plate are preferably of a diameter approximately equal to the diameter of the stem portion 54 of a respective screw 56 so that there limited play between the die plate and the screw carried by the main body unit of a respective hold-down device. The difference between the diameter of stem portion 54 of each screw 56 and the opening 80 in die plate 72, for example, may be of the order of 0.030 in. The same amount of latitude can be provided between stem portion 54 of screw 56 and a die mounted directly on a flat bed or rotary chase. The stem of the screw 56 having a washer 78 thereon, inserted through the hole 80 prepared therefor in die support plate 72 is threaded into the passage 52 of component 36. Rotation of screw 56 by a suitable allen wrench inserted in socket 60 is continued until the combination of washer 78 and head portion 58 of screw 56 is snugged down against the upper face of die support plate 72. Provision of washer 78 is preferred so that during final rotation of screw 56, the head portion 58 thereof does not impart rotational forces to the die plate 72. The same procedure would be followed in affixing a die to the surface of the flat bed or rotary graphic arts press chases.
In order to most expeditiously accomplish the foregoing, the chase cavity X-Y coordinate data is employed to establish precisely where holes 80 are to be drilled in individual dies or in the support plate 72. Based on that X-Y cavity location coordinate data, a CNC machine or the like is programed to drill holes 80 in support plate 72 or in the body of a die that receive screws 56 threaded into main body unit 12 of each respective hold-down device 10. The computer program for the CNC machine, using the X-Y chase cavity coordinate data, calculates where holes are to be drilled in predetermined positions in the support plate 72 or die so that screws passing through each hole will align with and be received in hold-down devices in corresponding chase cavities, with the design faces of the dies in precise alignment with the artwork images. In the event the hold-down devices 10 are not provided in all of the chase cavities, the die supplier can provide a film to the press operator that contains the artwork images and also marks, such as crosses, x's or the like, indicative of the chase cavities that should be provided with hold-down devices 10 for receipt of screws passing through the holes drilled in die support plates 72 or die. By laying that film over the chase, the press operator will readily understand where individual hold-down devices 10 should be inserted in particular chase cavities.
