BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an end perspective view of a cylinder illustrating an embodiment of the invention in use;
FIG. 2A is a top view of a jaw of a plate clamp as an element of an embodiment of the invention;
FIG. 2B is a top view of the other jaw of a plate clamp;
FIG. 2C is a side view of the plate clamp jaw illustrated in FIG. 2B;
FIG. 2D is an end view of FIG. 2B;
FIG. 3A is a top view of a clamp carrier utilized in an embodiment of the invention;
FIG. 3B is a front edge view of FIG. 3A;
FIG. 3C is an end view of FIG. 3A;
FIG. 4A is a plan view of a portion of an image-carrying plate;
FIG. 4B is a side edge view of FIG. 4A; and
FIG. 5 is a blow-apart illustration of an embodiment of the invention as attached to a cylinder.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As illustrated in FIG. 1, an image-carrying plate 10 is wrapped at least partly around the outer surface of a cylinder 11 and attached to cylinder 11 by plate clamps 12 which are attached to the ends of plate 10. Clamps 12 are coupled to clamp carriers 13 which are located in grooves or recesses 32 (FIG. 5) in the outer surface of cylinder 11. Conventionally, cylinder 11 has a hollow core for mounting the cylinder onto a rotatably driven shaft, not shown. Conventionally the shaft is cantilevered and the cylinder is removed by sliding the cylinder off the end of the cantilevered shaft and then replaced with a substitute cylinder. Typically and conventionally the equipment has features, not shown, which allow for minor adjustment for registration of the cylinder with attached plate when the cylinder is placed on and attached to its shaft. The. cylinder is usually made of a metal and may be a magnetic or nonmagnetic cylinder. Usually if a magnetic cylinder is used then a magnetically permeable plate is used and held in place by the magnetic holding field of the cylinder armaturing with the magnetically peremeable plate without the need for clamps 12 or clamp carriers 13. However, there are occasions when a user might want to attach a nonmagnetically permeable plate to a magnetic cylinder and, as mentioned earlier, many machines use a nonmagnetic plate with a nonmagnetic cylinder. The present invention serves either or both of the latter arrangements. Cylinder 11 has outer access openings 15 to permit adjustment of the clamp carriers 13 to pull the plate taut against the outer surface of cylinder 11. U.S. Pat. No. 6,443,064 by McEachern illustrates and describes mechanisms and method for adjusting a cylinder mounted on a shaft for accurate registration.
As illustrated more clearly in FIG. 4, typically an image-carrying plate 10 may be made out of a suitable material, such as aluminum for a non-magnetic plate or suitable metal for a magnetic plate, and thin enough so that it can be at least partially wrapped around the outside of the cylinder. The plate 10 has at least a pair of registration apertures or openings 16 at each end for engaging corresponding registration or indexing pins 17 (FIG. 2C) in plate clamps 12. The underside of plate 10, which rests against the cylinder surface, is usually smooth and unadorned and the upper or outer side carries an image 18 which is to be reproduced on or transferred to a suitable media, not shown. For illustration purposes only the image is shown as the letter “A” in block form.
Plate clamp 12, as illustrated in FIG. 2, comprises a pair of jaw members 12A and 12B. An end of plate 10 is clamped between the two jaw members with pins 17 engaging registration or indexing apertures 16. Jaw member 12A rests over jaw member 12B with the plate clamped therebetween and openings 20 on upper jaw member 12A are provided to accept threaded members 21A (FIG. 5) to engage threaded openings 21 on jaw member 12B to removably bring the two jaw members together firmly with an end of plate member 10 grasped firmly therebetween. Cutouts 22 in jaw member 12A are provided for access to threaded members 23 which extend through counter sunk openings 24 to engage threaded openings 25 for releasably attaching plate clamp 12 to clamp carrier 13. The underside of jaw 12B has a transverse recess or slot 27 for engaging a transverse raised section or rail 28 on clamp carrier 13. Also, pins 17 extend through jaw member 12B for engaging corresponding registration or indexing openings or recesses in clamp carrier 13.
As illustrated in FIG. 5, a pair of parallel T bars 30 are attached to cylinder 11 by threaded members 31 in the recess area generally designated by reference numeral 32. T bars 30 are engaged with T slots 33 on the underside of clamp carrier 13 so that clamp carrier 13 is movably engaged with cylinder 11 to permit circumferential adjustment, if needed, of plate 10 when mounted on the cylinder to permit the plate to be pulled taut so that it rests firmly against the outer surface of cylinder 11. As mentioned earlier and in conventional fashion, openings 15 are formed in cylinder 11 so that threaded adjustment members, not shown, can be inserted to engage threaded openings 35 located in the side of clamp carrier 13 and the adjustment members can be operated to move clamp carrier 13 circumferentially when plate clamps 12 with attached plate are coupled to clamp carrier 13 to ensure that plate 10 is pulled taut to rest firmly against the outside circumferential surface of cylinder 11.
In practice while one cylinder with attached image-carrying plate is in operation for transferring the image onto a media, another similar cylinder can be prepared to replace the cylinder in use with an image-carrying plate whose image likely must be registered with respect to the earlier transferred image. Each end of an image-carrying plate 10 is placed suitably between the clamping members or jaws 12A and 12B with the registration holes 16 engaged with the registration pins 17 and the clamp members secured together with threaded members 21A engaged in threaded openings 21.
Clamp carriers 13 are mounted in their respective recesses 32 on cylinder 11 with T bars 30 attached to the cylinder by threaded members 31 engaged in the tracks 33 on the underside of the clamp carrier 13.
The plate clamps 12 with plate 10 attached are then each placed on a corresponding clamp carrier 13 with the slot 27 engaging rail 28 and the underside of pins 17 engaging openings 19 in clamp carrier 13. Each plate clamp 12 is secured to its respective clamp carrier 13 with the respective threaded members 23 engaged in their respectively corresponding threaded openings 25. Only the plate clamps need be handled when mounting the plate onto the cylinder. Once mounted, if necessary, threaded adjustment members in openings 15 are engaged with threaded openings 35 on clamp carriers 13 and adjusted as necessary to move clamp carrier 13 to the degree necessary to pull the plate taut against the outer surface of the cylinder. Pins 17 and corresponding mating openings and/or recesses are machined or formed to quite close tolerances so that indexing or registration is very accurate.
The general practice is that when a plate is first mounted onto a cylinder as described hereinabove, the clamp carrier at one edge of the plate, usually the leading edge, locates that edge of the plate at an indexing location using conventional means and procedures, not shown or described. When the plate is replaced with another plate, as described hereinabove, the one clamp carrier locates that edge of the replacement plate at the indexing location and only the other clamp carrier is adjusted to pull the plate taut against the cylinder surface thereby insuring correct registration between the reproduced images of the respective plates. As mentioned earlier, generally the equipment is provided with features which allow for some minor adjustments if needed for more precise registration.
Patent Application
20080028964
