Abstract:
A friction pad assembly having a backplate fast with a pad support body for use in a brake of an unwind stand of a printing press to reduce or eliminate brake squeal. The friction pad reduces brake squeal by the method of affixing the backplate to the mounting body so that the friction pad and pad support are accoustically decoupled from the backplate.

Description:
FIELD OF THE INVENTION 
     This invention relates to a device to substantially reduce or eliminate brake squeal of a brake when applying tension to an industrial continuous material, for example: a paper web, wire, etc. from an unwind stand of an industrial process machine for example: a printing press, coating machine, etc. and, more particularly, to a friction pad having a backplate structure to eliminate that squeal. 
     BACKGROUND OF THE INVENTION 
     In printing press operations a variety of pneumatic brakes have been employed in an unwind stand of the press. Such brakes may be standard dual disc brakes, universal actuator brakes, single disc brakes, pod-style brakes, and caliper brakes. Typically, these brakes, when used to brake an unwinding roll of paper installed on the unwind stand, squeal adding noise to the surrounding environment making conservation difficult and operator discomfort a problem. 
     Therefore what is needed is a friction pad that reduces squeal to minimize noise pollution, resulting from such brakes, in the environment surrounding a printing press. 
     SUMMARY OF THE INVENTION 
     Wherefore, it is an object of the present invention to overcome the aforementioned problems and drawbacks associated with the prior art designs. 
     One object of the invention is to provide a friction pad that reduces brake squeal in printing press environs. 
     Another object of the invention is to improve safety and fatigue of a printing press operators by providing squeal free brake-pads to reduce environmental noise and pollution. 
     According to the invention, there is provided an anti-squeal friction pad assembly, for an unwind stand tension brake of a printing press, comprising: a backplate having a mounting surface, a pad support body having a brake pad attached thereto, said support body being fast with said mounting surface at discrete locations of said support body. 
     Also according to the invention there is provided an unwind stand of a printing press having a tension disk brake including an anti-squeal friction pad assembly; the assembly comprising; a backplate having a mounting surface, a pad support body having a brake pad attached thereto, said support body being fast with said mounting surface at discrete locations of said support body. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described, by way of example, with reference to the accompanying drawings in which: 
     FIG. 1 is an diagrammatic exploded view a preferred embodiment of a friction pad back plate structure according to the present invention; 
     FIGS. 2A and 2B are diagrammatic views of a preferred embodiment of a friction pad assembly according to the present invention; and 
     FIG. 3 is a diagrammatic view of a brake assembly used with an unwind stand and using a brake pad assembly according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Turning now to FIGS. 1-3, a detailed description concerning the present invention will be provided. 
     FIG. 1 shows a friction pad back plate structure  2  according to the present invention. A flat backplate  4  is provided with a pad locating opening  6 . Further provided on the backplate, opposed from the opening hole  6 , is a pad locating cutout  8 . Both the opening  6  and the cutout  8  have a diameter of about 0.50 to 0.55 inch. The structure  2  is further provided with a flat circular support plate  10  that is mounted to a mounting surface  12  of the backplate  4 . The support plate  10  is spot-welded to the backplate  4  at four locations  14  evenly spaced circumferentially around the plate  10  about ⅛ to ¼ inch from the outer edge of the plate  10 . The support plate  10  is provided with a cutout  16  sized to correspond with the cutout  8  of the backplate body  4 . The backplate body and the support plate are provided with aligned throughbores  18 , 19 ,  20 ,  21 . The diameter of each throughbore is about 0.50 to 0.55 inch. The throughbores consist of central throughbores  19 ,  21 , aligned along axis X, with four matching satellite throughbores  18 ,  20  evenly spaced about axis X. Further, it is to be appreciated that brake pad friction material (not shown in FIG. 1) is mounted to the support surface  22  of the support plate  10  to complete the friction pad assembly  24 . 
     FIGS. 2A and 2B illustrate an assembled anti-squeal friction-pad assembly  24  with friction pad  26  in the form of a brake pad friction material  26  fast therewith. Although an optional feature, the material  26  covers a perimeter portion  28  encasing support plate  10  (see FIG.  2 B). It is to be appreciated that when the material  26  is affixed to the perimeter portion  28  of the backplate  4 , the opening  6  and cutouts  8 ,  16  are unobstructed so that two appropriately sized studs  29  (see FIG.  3 ), by using opening  6  and cutouts  8 ,  16  prevent rotation of the friction pad assembly  24  relative to a structure of an unwind stand (see FIG.  3 ). In this embodiment, the backplate  4  and support plate  10  have an thickness t 1  and t 2  of about 0.05 to 0.1 inch, giving the friction pad assembly  24  a thickness t 3  of about 0.3 to 0.5 inch. 
     Turning now to FIG. 3, there is shown a diagrammatic sectional view of a printing press unwind stand  30  illustrating a disk brake having a friction pad of the present invention. A stationary machine frame  32  of the unwind stand  30  supports, via a bolts and spacer  34 ,  36  (one only being shown), an backing plate  38 . The plate  38  supports a pneumatic cylinder housing  40  having a piston  42 . Restrained, by the opening  6  and cutouts  8 , 16  on guide studs  29 , the friction pad assembly  24  is moveable into frictional engagement with a brake disk  48 . It is to be appreciated that a pressurized air supply  44 , via a supply port  46  provided in the actuator plate  38 , operates the air cylinder assembly  40 ,  42  to move the friction material  26  of the friction pad assembly  24  to engage the brake disk  48 . The brake disk  48  is connected, via a hub assembly  50 , to a rotatable shaft  52  of the unwind stand. When the friction pad assembly  24  engages the braking disk  48  and the shaft  52  of the unwind stand  30  supporting a roll of paper (not shown) is braked to apply a desired tension to a web of the paper in dependence on the pressure derived from the air supply and the friction of the pad engagement with the disk. By the construction here described, the presence of brake squeal in brakes found in the prior art of such apparatus is greatly reduced or eliminated. 
     It is to be appreciated that the pad support plate  10  to which the brake pad friction material  26  is attached may be attached to the mounting surface  12  of the backplate  4  as described above to provide the mounting at discrete locations using any number of methods well known to those skilled in the art, e.g. spot welding, brazing, adhesives, including epoxy adhesives, rivets, etc. . . Also that such mounting methods may be utilized generally anywhere on the support plate  10  including around at least a portion or the entirety of its perimeter. Furthermore, that such above mentioned methods of mounting the support plate  10  to the backplate  4  result in the support plate  10  being fast with but acoustically decoupled from the backplate  4 .