Abstract:
A method for texturizing a workpiece uses a die assembly installed within a press having a press ram. The method includes (a) delivering the workpiece onto a center die plate; (b) forcing the press ram against an upper die plate mounted above the center die plate to descend a first contact surface associated with the upper die plate and a plurality of blades mounted to the upper die plate toward the center die plate; (c) actuating horizontal movement of the blades; (d) driving the blades down into the workpiece; and (e) contacting the first contact surface to a second contact surface associated with the center die plate to descend the center die plate in unison with the upper die plate.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 14/877,375 filed Oct. 7, 2015 (now U.S. Pat. No. 9,623,477, issued on Apr. 18, 2017), which is a continuation of U.S. patent application Ser. No. 13/706,120 filed Dec. 5, 2012 (now U.S. Pat. No. 9,199,322, issued on Dec. 1, 2015), which claims priority from Canadian Patent Application No. 2,760,923, filed Dec. 6, 2011 (now CA Pat. No. 2,760,923, issued Mar. 11, 2014), each of which is incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to apparatuses for texturing the surface of a brake plate. 
     Description of the Related Art 
     Secure brakes being all-important, the use of textured plates to anchor the friction pad is extremely desirable. However, the additional cost of plate texturing limits their real-world use to severe-service and high-end vehicles where the added cost is irrelevant. It would be desirable to lower the cost of texturing brake plates so that more widespread use could be made of this safety feature. 
     SUMMARY OF THE INVENTION 
     An apparatus is provided for texturing the surface of a brake plate having three die plates and spring supports therebetween. A toothed tooling mounts to the top die plate above an anvil on the centre die plate both of which ride on posts held by the lower die plate. The toothed tooling comprises multiple blades each with multiple replaceable toothed inserts which are held in s cartridge arrangement. The anvil receives brake plates from a separately supported plate feed mechanism. The complete die set can be set up on the bench and inserted ready to use in any style of press where the press ram contacts the upper die plate. 
     The three die plates of the present invention are all aligned on vertical posts. The posts are secured to the bottom or base die plate such that the centre and upper die plates are free to reciprocate thereon with the upper die plate uniquely carrying the texturizing tooling. In this way the entire die set installs as a free-standing one-piece assembly. The die set is mountable in a mechanical, hydraulic or servo type press. 
     This contrasts with prior apparatuses of this type in which texturizing tooling was attached to the press ram. This required that the lower, two-plate die set had to be precisely located beneath—a difficult task given the mass of the die set. 
     Certain support and actuation members are secured to the base die plate. Certain anvil structures are secured to the centre die plate. Certain cutting and press contact structures are secured to the upper die plate. 
     Accordingly, an apparatus is provided for texturing the surface of a brake plate. The apparatus comprises an independent and free-standing die set for use within a press. The die set has: a base die plate; a centre die plate, and an upper die plate. The base die plate is attachable to the press and has a series of fixed posts extending upward therefrom. The centre die plate is mounted above the base die plate on the posts and is also movable thereon. The centre die plate has an anvil portion for receiving a brake plate to be textured. The upper die plate is mounted above the centre die plate on the posts and is also movable thereon. The upper die plate has a tooling assembly with a plurality of oppositely acting blades located above the anvil portion. Opposing cam blocks are mounted below the upper die plate adjacent the oppositely acting blades. All of the plates are arranged in series such that downward force from the press urges the upper die plate into contact with the centre die plate, and the centre die plate downward toward the base die plate, and thereby actuates the cam blocks to drive teeth of the oppositely acting blades across and into the surface of the brake plate on the anvil. This action textures the surface of the brake plate. The base die plate is the only portion of the die set that attaches to the press. 
     For example, the base die plate may be built on a thick steel plate that boils to the bolster of the press machine. Preferably, the plates are spring-biased apart. Four permanent vertical posts and tour removable gas springs are arranged on the base. The springs may be manifolded together to equalize their spring rate and gas delivery so as to provide balanced support for the center die plate. By altering the gas pressure, the gas spring force can be adjusted for different sizes (surface areas or thicknesses) of brake plates to be textured (by providing more or less cutter action). 
     In one embodiment, the base die plate further includes opposing riser blocks, and the centre plate further includes opposing openings directly above the riser blocks. The riser blocks then extend through the openings to contact portions of the cam blocks to actuate the earn blocks as the upper and centre die plates descend. Preferably, each earn block has a vertical motion member and a horizontal blade moving member. The vertical motion member receives counterforce from the riser blocks, and engages into motion the horizontal blade moving member. The moving cams move the blades to carry out the texturing, (It will be appreciated that other methods of linear actuation of the blades are also possible.) 
     According to one embodiment, in operation, the press ram descends onto the upper die plate. The upper die plate then descends, engaging the two cams simultaneously. This initiates blade travel slightly prior to the cutting teeth inscribing the plate to create the required hooked burrs. In this way the cutting teeth are in horizontal motion before they drive down into the plate. The ram then ascends and the above the sequence of actions are reversed. The now textured plate is pushed off the anvil by s new incoming plate and the process repeats itself. 
     Smooth operation of the die set is desirable. The upper die plate may reciprocate on the posts via bushings. Its upper surface is contacted by the press ram. Preferably, the upper die plate has at least one elastomeric shock absorber disposed on an upper surface thereof. Multiple (preferably urethane) shock absorbing pads may be disposed on the top surface of the upper die plate. These pads are held in counterbored recesses such that the descending press ram contacts these pads first, thus providing a smooth and silent initiation of downward motion of the upper die against the initial resistance offered by the small gas springs. 
     The apparatus may further include a plate feed mechanism engageable with the centre plate. The plate feed mechanism has a magazine for holding brake plates to be textured; and a reciprocating slide mechanism for pushing brake plates onto the anvil one by one as they descend from the magazine. Preferably, the load of the magazine is supported independently of the die set. Preferably, the plate feed mechanism is detachable from the die set. Preferably, the plate feed mechanism further includes a pawl for preventing rearward motion of the brake plate. Preferably, the reciprocating slide mechanism has a variable delivery angle. 
     The weight of the plate feed mechanism is preferably supported on a solid mounting block secured to the base die plate (or press bolster). This greatly reduces the reciprocating mass on the die set allowing a higher rate of reciprocation for faster plate texturizing and reduced cost. Reduced reciprocating mass also eliminates expensive wear from side thrust on the die set posts and bushings which would otherwise occur if the entire plate feed mechanism were cantilevered from- and made to reciprocate with the die plate, as is the case in the prior art. Such wear necessitates the tear down of the entire die set to replace the worn posts and bushings. The result, is a long non-productive down-time to rebuild the dies and the attendant labour expense. 
     The plate feed apparatus comprises a plate magazine assembly, a plate teed slide assembly, and a pneumatic linear actuator for the slide, all supported by the solid mounting block on the base die. The plate slide assembly uses long steel strips as slides in a laminated assembly which are separate from, but pass through and are guided by, the magazine assembly. The slides connect to a hinge block at their outboard (distal) end. This hinge block is separately supported on rods extending from that same solid mounting block (on base die plate die) along which rods it can reciprocate along with the plate slides. These rods also support the stationary actuating cylinder (pneumatic) which reciprocates the hinge block and slides. The inner (proximal) end of the lower plate slide rests on rollers secured to the edge of the centre die. The upper slide plate has features to receive a plate from the stack of plates held in the magazine above. Thus when the cylinder is activated, the reciprocating slides pick up plates on each rearward stroke and deliver the plates in a train-like flow to the anvil for texturing. Spring-loaded pawls or detents prevent the plates from moving backwards with the slide. In this way only a very small portion of the total weight of the plate feed mechanism is reciprocating with the centre die. Thus the posts and bushings do not experience the heavy wear known to be a serious problem with prior methods of plate delivery. 
     Various blade arrangements are possible. Preferably, the blades are opposingly arranged in the tooling assembly, such that adjacent blades have teeth oriented in opposed directions. The blades may be solid cutting knives, or may include modular inserts. Each blade preferably has at least one cut-out for receiving at least one insert. The insert has a first end on which is disposed a plurality of cutting teeth and a second end having a bulbous projection shaped to loosely engage a correspondingly shaped recess in the at least one cut-out. Preferably, the insert when inserted into the cut-out leaves a gap below the bulbous portion. Preferably, the insert is shaped to wedgingly engage the recess to narrow the gap under force of operation in the press. 
     Preferably, the inserts and cut-outs have corresponding side taper portions for seating and bulbous bottom portions for retention. The bulbous portion of the cut-out is slightly deeper that of the insert. Thus, there is a gap between the bottom surface of the insert, and the bottom surface of the cut-out. In operation the incising force acting on the cutting edge is able to drive the insert a small distance into the tapered cut-out such that the insert wedges very tightly, effectively immobilizing the insert in the blade. Because carbide is very friable and fractures easily if allowed to shudder or vibrate under the high cutting forces required to incise steel, this rigidity greatly prolongs the life of the teeth which reduces costs and reduces press down-time for tooling change-out. 
     The blade cartridge comprises the cutter blades (with the aforementioned toothed inserts) slidingly held in precisely aligned rows between robust side supports that are secured to a common backing plate which has mounting rails to sliding engage grooves in a plate attached to the top die. The blades and the side supports all have open slots at each end that are in alignment and through which slots are pins that extend outboard of each side support to provide attachment for return springs stretched between the two ends of the two pins. The rows of blades are off-set alternately such that the cams at each end actuate only half the blades which therefore move in opposite directions. 
     Preferably, the blades are spring-loaded such that each tooth makes, a relatively short gouged inscription and a retention hook on the brake plate before retracting and disengaging from the brake plate. 
     The upper die plate may be spaced away from the centre die plate for permitting removal and re-insertion of the fooling assembly (e.g. by support from smaller gas springs). The blade cartridge is preferably constructed for easy tooling change-over and maintenance. Preferably, the tooling assembly is mounted to the upper die plate on rails for permitting removal and re-insertion of the tooling assembly. Preferably, at least one sensor is provided on or near the die set proximate to the anvil for monitoring the texturing operation, of the tooling assembly (e.g. to monitor hook formation). Sensors may detect the height of undersized burrs and/or ill-positioned plates and thereby provide input to machine controls to stop, the texturing process preventing inferior plates from leaving the press. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the present invention can be understood, in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
         FIG. 1  shows a perspective view of the die set with the base, centre and upper die plates, the cam blocks and blade cartridge, and the location of the plate feed mechanism in dashed outline. 
         FIG. 2  shows the plate feed mechanism from the side in its forward position of plate delivery. 
         FIG. 3  shows the same as  FIG. 2  in the rearward position for plate pickup. 
         FIG. 4  shows the blade and insert tooth arrangement and: an enlargement thereof. 
         FIG. 5  shows the prior art dies set in a press with the tooling secured to the ram face. 
         FIG. 6  shows the instant three plate die set in the same press with the tooling secured to the upper die plate. 
         FIG. 7  shows a simplified side view of the instant invention in its resting state so as to clearly disclose the blade movement sequence. 
         FIG. 8  is an enlarged left portion of  FIG. 7  where the upper die plate contacts the centre die plate. 
         FIG. 9  is the same as  FIG. 8  but with the two die plates moving in unison. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings, there are sometimes shown small gaps or spaces between components. This is for clarity of understanding but in actual fact most components fit tightly together except where otherwise noted. 
     In  FIG. 1  the instant three piece die set  100  has as its major components: upper die plate  200  with tooling assembly  400  and associated cam blocks  300 ; centre die plate  500  with anvil  26 ; base or lower die plate  600  with posts; and plate feed mechanism  700 , shown as a placement outline in  FIG. 1  and in greater detail in  FIGS. 2, 3 . Die set  100  installs in press  900  ( FIG. 6 ) where it is attached to its bolster plate E. Press  800  and  900  have base F and upper frame B connected together with tie rods C. Cylinder G has ram D that is reciprocated therein. The press  900  may be mechanical, hydraulic, or a servo type press. 
     The prior art show in block outline in  FIG. 5  uses a two plate die set with tooling attached to the press ram. This makes it difficult to install, adjust, test and change-out the tooling. Critically, the alignment of the tooling with the die set is also difficult given the mass of the die set (many hundreds of pounds) and the need for its precise location beneath the separately mounted tooling.  FIG. 6  shows the same press with the three plate die set of the instant invention and how the tooling alignment is pre-set prior to installing on the press where the die set location is not critical and therefore much easier and faster. 
     Referring back to  FIG. 1 , base die plate  800  has base die plate  33  (with means to secure it to press bolster E), four rigid posts  30  secured in stop blocks  35 , two stepped riser blocks  36  with upper contact faces  36   a . A removable slide  38  carries four manifolded gas springs  37  and is located by two guides  31 . On base die plate  33  is rigid block  34  with attachment means  32  to secure plate teed mechanism  700  thereto. 
     Upper die plate  200  has elastomeric pads  6  secured in recesses  5  in the top surface of plate  1  as shown by arrow  7 . These pads are compressed by the descending ram D making for a cushioned, silent contact with top die plate  1  and which also initiate the descent of upper plate  200 . Four through-bushings  4  slide on posts  30 . Cam blocks  300  attach to the underside and are separated by pressure plate  2  which has guides  3  to receive fooling rails  18  on tooling assembly  400 . 
     Referring to  FIG. 1  and  FIGS. 7-9  (where  FIGS. 8, 9  show simplified left half views of  FIG. 7  for enlarged clarity) left and right cam blocks  300  have secured body portions  8  with guided, spring-return moving elements. When die plate  200  descends each vertical moving element  9  contacts surface  36   a  of riser block  36 . Elements  9  have angular contact surfaces  9   a . Each horizontal moving element  10  has a matching angular contact surface  10   a . As die plate  200  descends, these angular surfaces engage in a sliding contact such that the horizontal moving elements  10  move towards each other. Toothed blades  11 ,  14  held in tool assembly  400 , are arranged to move under the force of horizontal moving elements  10 . Horizontal blade motion is timed to begin just slightly before the teeth contact the brake plate A. In this way, the teeth skate ( 21   a  in  FIG. 8 ) into plate A to avoid unwanted sudden impact that would damage the sharp tooth tips. After a certain distance of vertical descent of die plate  200 , shown change in gaps  67  and  67   a  in  FIGS. 8, 9 , secured body portions  8  contact secured blocks  29  causing centre die plate  500  to thereafter descend with descending die plate  200 . As descent of the upper and centre die plates continues, gap  66  between die plate  200  and die plate  600  is reduced to gas  66   a , the descent being resisted by the adjustable force of gas springs  37  which allows teeth  21  to continue incising controllably across and into plate A, as indicated by buried teeth  21   b  in  FIG. 9 , Removable shims  68  in riser blocks  36  allow precise adjustment to compensate for varying thicknesses of plate A and for manufacturing/specification tolerances. 
     Centre die plate  500  has plate  22  with four post through-bushings  24  (to slide on posts  30 ) an anvil plate  26  on which brake plate A, is delivered between guides  25  for texturing. Openings  24  enable stepped riser blocks  26  to protrude through plate  22  and to contact vertical moving element  9  mounted in cam block  8 . Centre die plate  500  also has four gas springs  27  of sufficient strength to hold upper die plate  200  open over centre die plate  500  for rapid tooling change-out. Pressure blocks  29  have upper contact surfaces  28  that contact cam block contact surfaces  9   a  and transfer downward motion of upper die plate  200  to centre die plate  500  such that both move downwards together compressing first gas springs  27  then gas springs  37 . On the edge of plate  22  are two roller supports  29  on which rests and pivots the inboard end of plate feed slides  44 ,  44   a.    
     Upper die plate  200  holds quick-change tooling assembly  400  which includes left blades  11  and right blades  14  having shorter and longer slots  20  formed in end portions. Blades  11  and  14  are arranged in alternating rows and are slidingly held between rigid side fences  13 ,  15 . The arrangement is such that the blades are offset horizontally and their respective teeth  21  are pointing in opposite directions. Spring loaded left and right pins  16  engage the blades&#39; slots and co-operating slots in the side fences  15 . Pins  16  are tensioned towards each other via outboard springs  19 . In this way blades  11 ,  14  are made to move in opposite directions so as to cancel out their inscribing forces making it unnecessary to clamp, brake plate A which speeds production. The side fences  13 ,  15  are bolted  12  to a pressure plate  17  and the plain backs of the blades also contact plate  17 . Pressure plate  17  has rails  18  secured to its top surface that slidingly engage guide slots  3 . 
     Attention is now drawn to  FIGS. 2, 3  which show a side view representation of plate feed mechanism  600  at each end of its operational stroke,  FIG. 2  shows the brake plate delivery position while  FIG. 3  shows the rearward brake pick up position. Main magazine member  41  includes brake plate support rods  42  and is mounted rigidly to rigid block  34  on base die plate  33 . Brake plates A drop through an opening in member  41  onto reciprocating slide  44  with sub-slide  44   a  beneath. Both slides pass freely through member  41  and are guided by same. Extending from rigid block  34  are rigid support rods  51  along whose length slide block  50  can be adjustably secured. Slide block  50  holds a separate hinge plate  50   a  pivoted thereon via cross pin  45  and shown by arced arrow lines  43 . Slides  44 ,  44   a  are secured to hinge plate  50   a . Also adjustably secured to rods  51  is a pneumatic cylinder  49  with mounting boss  43  and piston rod  47  which is secured to hinge block  50  such that rod  47 , slides  44  and  44   a , hinge block  50 , and hinged plate  50   a , all reciprocate together along support rods  51 . In this way, brake plates A drop by gravity onto upper slide  44  and are moved one by one onto anvil  26  by the reciprocating action of pneumatic cylinder  49  which is timed to the reciprocating movement of the press  900 . Rollers  39  support the inboard ends of slides  44 ,  44   a  and brake plates in conveyance, and allow free reciprocation left to right on anvil  26  as brake plates are successively delivered thereon. Rollers  39  also move the slides up and down as the center die plate so moves. 
     Slides  44 ,  44   a  are made extra long which serves a very important function, namely, it reduces the variation in delivery angle  46  of the brake plate to the anvil  26  between guides  26   a . This means that the brake plate can be delivered with only a small variation in height. This avoids a jamming condition frequently encountered in prior apparatuses which reciprocate the entire brake plate feed mechanism with the centre dies plate. Attached to magazine member  41  are pawls  40 , one of which is shown, which serve as one way controllers to prevent the rearward movement of brake plates resting on the slide  44  which necessarily must travel rearwards. 
     Referring now to  FIG. 4 , blades  11 ,  14  have end slots  20  and cut-outs  63 . Cut-outs  63  receive inserts  61  such that enlarged or bulbous portions prevent the insert from falling from the blade. Certain inserts have cutting teeth  21 . Certain inserts may also have no teeth (not shown). These are used as non-cutting spacers. Alt inserts have angled side portions  62 . Cut-outs have matching angled sides  64  to provide a close fit with the inserts. It is desirable to prevent relative motion between the inserts and their respective cut-outs which can lead to tooth breakage and expensive production stops to correct. As can be seen in the magnified view in  FIG. 4  there is provided a cut-out having a slightly deeper bulbous portion indicated by  65 . Each insert  61  can then be driven by forces of operation  70  into a jammed tight condition whereby intimate contact between the walls of the insert and cut-out cannot be interfered with by their bulbous portions contacting first. 
     Although the invention has been shown and described with respect to detailed embodiments thereof, it should be understood by those skilled in the art that various changes in form and detail thereof may be made without departing from a broad purposive construction of the claimed invention. For instance, although brake plates have been used as an example throughout the foregoing disclosure, it will be appreciated that the methods and apparatus described herein may be equally applicable to texturing other workpieces. 
     While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.