Abstract:
A template holder bracket and method of assembling and disassembling a template from the bracket. The bracket has a spring pin assembly that is secured to the bracket that holds the template in a locked position. The spring pin assembly includes a pin, a housing and a spring that biases the pin into engagement with the template. The template may be removed by rotating the template against a ramp surface on the pin assembly that disengages the pin from the template against the biasing force of the spring.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional Application No. 61/485,382 filed May 12, 2011, the disclosure of which is incorporated in its entirety by reference herein. 
    
    
     TECHNICAL FIELD 
     A template bracket for a part holding fixture that is used to hold parts between operations on a manufacturing line. 
     BACKGROUND 
     Manufacturing and assembly lines may be loaded and unloaded by robotic devices. The robotic devices may pick up work pieces from a fixture or holding device and load them into an operation in a press, a welder, or the like. Between operations, a robot may unload the part and place it on another fixture. 
     A variety of different parts may be processed on the same manufacturing line. The parts processed on a line may have different shapes that require differently shaped templates on the fixtures to support the parts. Manufacturing lines may be changed over relatively frequently to accommodate different part styles that have different shapes and require different fixture locating points. The templates retained by the template holder brackets must be locked in place. Properly locating fixture templates minimizes the risk of damage to the parts as a result of the parts being placed upon improperly located fixture templates. 
     Some prior art fixture templates were secured to brackets by means of two pins that are inserted through a wall of the bracket and into corresponding holes in the base of the template. With this approach, workers may inadvertently fail to insert one or both pins leaving the template in an unstable condition. The pins are generally removed completely from the bracket and set aside until a new template is to be secured to the bracket. The pins may be misplaced or lost when they are removed from the bracket. 
     In a modification of the template, a slot may be provided in the template base that receives a pin that is permanently secured to one end of the bracket. The template base is then secured by inserting a removable pin into the side of the bracket and the template base to hold the template base in place. This approach permits one of the removable pins that is generally required to hold the template in the bracket to be eliminated, but still leaves one removable pin that is required to lock the template into the bracket. 
     Applicants&#39; invention is directed to solving the above problems relating to fixture templates that are secured to brackets by one or more removable pins. 
     SUMMARY 
     According to one aspect of this disclosure, a template bracket assembly is provided for holding a template for a part holding fixture in a manufacturing operation. The template bracket assembly comprises a bracket defining a slot for receiving the template. A pressure pin assembly retained by the bracket includes a pin that may be shifted between a locking position and a released position. A spring element biases the pin into the locking position. The template is retained in the bracket when the pin is in the locking position. The template is released from the bracket by shifting the pin to the released position without removing the pin from the bracket. 
     According to other aspects of the disclosure, the pin may define a ramp surface on a distal end of the plunger that facilitates disengaging the second portion of the plunger from the template. The ramp surface may form a crowned end of the plunger, or alternatively, the ramp surface may be a flat beveled surface that is contiguous with the distal end of the plunger. 
     The pressure pin assembly may further comprise a support member that engages a surface formed inside a housing that is engaged by the pin that forms a pin assembly. The support member may be adjusted to change the effective length of the pin assembly. Changing the length of the pin assembly changes the extent that the pin protrudes into the slot and the extent that the spring element biases the pin. 
     The template bracket assembly may further comprise a clip engaging a support plate that is part of the bracket and that is attached to the pressure pin assembly. A flange extends radially outwardly from the pressure pin assembly. The support plate defines a receptacle hole and also defines a recess about the receptacle hole that receives the flange so that the pressure pin assembly may be secured to the support plate between the clip and the flange. 
     The pressure pin assembly may further comprise a handle that is attached to an outside end of a shaft that extends through the pressure pin assembly and is attached to the pin. The pressure pin assembly may define a seat that receives the handle in the locking position. The handle may be pulled from the seat to move the pin to the released position without separating the pressure pin assembly from the bracket. 
     According to another aspect of the disclosure, a pressure pin assembly is provided for a template bracket that holds a template for a part holding fixture in a manufacturing operation. The template bracket comprises a support plate defining a receptacle hole that receives the pressure pin assembly, a back-up plate disposed in a parallel orientation spaced from the support plate. A spacer may be disposed between the support plate and the back-up plate. The support plate, spacer and back-up plate are secured together in a fixed relationship. The pressure pin assembly includes a plunger and a housing defining a bore that receives a first portion the plunger in one end of the housing with a second portion of the plunger extending from the housing. The housing is assembled to the support plate with the second portion of the plunger protruding from the support plate toward the back-up plate. A biasing element, such as a spring, engages the plunger and biases the plunger toward the back-up plate. The template may be inserted between the support plate and the back-up plate. The template defines a recess that at least partially receives the second portion of the plunger to temporarily retain the template in a fixed position. The template may be removed from the template bracket by rotating the template about an axis radially spaced from the plunger to disengage the second portion of the plunger from the recess against the biasing force of the biasing element. 
     According to further aspects of the disclosure, the recess in the template may be a hole that extends through the template. The plunger may define a ramp surface on a distal end of the plunger that facilitates disengaging the second portion of the plunger from the template. 
     The pressure pin assembly may further comprise a support bolt having a head that engages a shoulder formed inside the bore. The plunger may define a threaded bore on an inner end of the plunger that receives the support bolt to form a plunger assembly. The support bolt may be rotated to change the effective length of the plunger assembly and thereby change the extent that the plunger protrudes from the support plate and the extent to which the biasing element biases the plunger. 
     The pressure pin assembly may further comprise a clip engaging an outer surface of the support plate that attaches to an outer surface of the housing and a flange extending radially outwardly from the housing. The support plate may define a recess about the receptacle hole that receives the flange so that the housing may be secured to the support plate between the clip and the flange. The clip may be a spring clip, the flange may be a circular rim, and the recess may be a circular recess that receives the rim. 
     Alternatively, the pressure pin assembly may further comprise a handle that is attached to an outside end of a pin that extends through the housing with an inside end of the pin being attached to the plunger. The housing may define a seat that receives the handle in a locking position in which the plunger is received in the recess in the template. The handle may be pulled from the seat defined by the housing to withdraw the plunger from the recess in the template and moved to an unlocking position. 
     A method is disclosed for assembling a template to a bracket that defines a slot for receiving the template and a pressure pin assembly that is attached to the bracket. The method may comprise a first step of inserting the template into the slot. The template may then be located relative to the bracket by aligning the pressure pin assembly with a recess defined in the template. A movable pin of the pressure pin assembly is shifted in a direction that is normal to a surface of the template that defines the recess. The movable pin locks the template within the bracket when the pin is partially received in the recess. The template is removed from the slot by moving the template within the slot perpendicular to the direction that the pin is biased. 
     According to other aspects of the method, a locating pin may be provided on the bracket and the template may define a slot. The step of inserting the template into the slot may further comprise placing the template in the bracket with the slot receiving the locating pin. The template may then be rotated within the slot until the pin is partially received in the recess. The step of removing the template from the slot may further comprise rotating the template about the locating pin to separate the pin from the recess. The movable pin may include a beveled surface that functions as a ramp surface for moving the pin against the force of a spring that biases the movable pin in a direction normal to the surface of the template that defines the recess. 
     Alternatively, the movable pin may include a handle that is attached to an outside end of the pin with an inside end the pin being attached to the movable pin. A seat may receive the handle in a locking position in which the pin is received in the recess in the template. The step of shifting the movable pin may further comprise placing the handle in the recess. The step of removing the template from the slot may further comprise pulling the handle from the seat to withdraw the pin from the recess in the template. By pulling the handle, the pin is moved to a release position while keeping the pressure pin assembly attached to the bracket. 
     These and other aspects of the disclosure will be better understood in view of the attached drawings and the following detailed description of the illustrated embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a fragmentary perspective view of a part holding fixture showing a template supported by a bracket on a rail of the fixture; 
         FIG. 2  is a perspective view of a template holder bracket; 
         FIG. 3  is an exploded perspective view of a template holder bracket and spring pin; 
         FIG. 4  is a cross-sectional view taken along the line  4 - 4  in  FIG. 2  of the bracket and the spring pin; 
         FIG. 5  is a top plan view of a template holder bracket and spring pin; 
         FIG. 6  is a front elevation view of a template holder bracket and spring pin; 
         FIG. 7  is a side elevation view of a template holder bracket and spring pin; and 
         FIG. 8  is an exploded perspective view of an alternative embodiment of a template holder bracket and spring pin. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed embodiment of the present invention is disclosed in this application. The disclosed embodiment is merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed in this application are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art how to practice the present invention. 
     Referring to  FIG. 1 , a bracket  10  is shown with a template  12  that has a part engaging surface  14 . The template  12  is positioned above the bracket  10 , ready to be installed in the bracket. The template  12  is used to support a part (not shown) in a manufacturing process between manufacturing operations. The bracket  10  is secured to a base rail  16  of a fixture that supports the template  12  and holds the part at a convenient height. 
     The template  12  is secured to the bracket  10  by a pressure pin assembly  18  and a fixed pin  20 . The template  12  has a template base portion  22  that is engaged by the pressure pin assembly  18  and that also receives the fixed pin  20 . A hole  24 , or recess, is provided in the template base portion  22  that is engaged by the pressure pin assembly  18 . An angled slot  26  is provided in a vertically extending edge  28  of the template  12  that receives the fixed pin  20 . The edge  28  is the leading edge of the template base portion  22  when the template  12  is inserted into the bracket  10 . A rounded corner  30  is provided on the lower corner of the template base portion  22  below the angled slot  26 . The rounded corner  30  provides clearance for rotation of the template  12  about the fixed pin  20 . During installation, the template  12  is rotated about the fixed pin  20  until the pressure pin assembly  18  is received in the hole  24 . The illustrated hole  24  is a through hole, however, it would be possible to provide a recess that does not extend through the entire thickness of the template base portion  22 . 
     A base surface  32  of the template base portion  22  may include a recess for receiving one or more locating pins, or screw heads, as will be more fully described below with reference to  FIGS. 3 and 5 . 
     Referring to  FIG. 2 , a bracket  10  is shown to be comprised of a support plate  34  that is connected to a back-up plate  36  through a spacer plate  38 . The support plate  34  supports the pressure pin assembly  18 . The back-up plate  36  backs up the template base portion  22  (as shown in  FIG. 1 ) against the force applied by the pressure pin assembly  18 . The spacer plate  38  spaces the support plate  34  and back-up plate  36  apart by the width of the template base portion  22 . As shown in  FIG. 2 , a plunger  40  of the pressure pin assembly  18  protrudes slightly into the space between the support plate  34  and the back-up plate  36  to exert a biasing force on one side of the template base portion. The plunger  40  has a crowned end  42  that is beveled or generally convex in shape. The crowned end  42  provides a ramp surface that facilitates insertion of the template  12 , as shown in  FIG. 1 . A pin housing  48  extends outwardly from the support plate  34 . 
     A pin housing  48  extends through a hole  50  defined in the support plate  34 . The support plate  34  and back-up plate  36  are securely fastened together by means of bolts  52  and locating pins  54  that secure the back-up plate  36 , as shown in  FIG. 2 , to the spacer plate  38 . 
     Referring to  FIGS. 3 and 4 , an exploded perspective view and a cross-sectional view of the pressure pin assembly  18  are provided to illustrate the structure and function of the pressure pin assembly  18 . The pin housing  48  is inserted from the inside of the support plate  34  through the hole  50 . The plunger  40  is supported within the housing  48  with its crowned end  42  extending inboard of the support plate  34 . A helical spring  56  is received about a support bolt  58 . The support bolt  58  is received in a threaded hole  60 , shown in  FIG. 4 , formed in the plunger  40 . The spring  56  engages the plunger  40  about the support bolt  58  on one end and on the other end engages a shoulder  62 , or lip, formed within the housing  48 . A bolt head  64  is received within the housing  48  on the opposite side of the shoulder  62  from the plunger  40 . It is preferred that the pressure applied by the pressure pin assembly  18  be set at a predetermined level established by the selection of the spring  56 . The spring force selected should permit insertion and removal of the template  12  with a controlled level of force that provides a rigid holding force, but a force that may be easily overcome by rotating the template  12  about the fixed pin  20 . As the template is rotated, the template base  22  shifts the plunger  40  that compresses the spring  56 . 
     The pressure pin assembly  18  is secured to the support plate  34  by a spring clip retainer  66  that captures the support plate  34  between a rim  67  of the pin housing  48  and the spring clip retainer  66  that is received in a slot  68  formed on the exterior of the pin housing  48 . 
     Referring to  FIG. 3 , the back-up plate  36  is secured by bolts  52  and locating pin  54  to the spacer plate  38 . Either the support plate  34  or back-up plate  36  may be disassembled from the spacer plate  38  when the pressure pin assembly  18  is secured within the hole  50  provided in the support plate  34 . The pin housing  48  is inserted from the inside of the support plate  34  into the hole  50 . The pressure pin assembly  18  is secured on the outer side of the support plate  34  by the spring clip retainer  66 . Before assembling the pressure pin assembly  18  to the support plate  34 , the plunger  40 , helical spring  56  and support bolt  58  are assembled together and inserted into the pin housing  48 . When the pressure pin assembly  18  is assembled to the support plate  34 , the crowned end  42  of the plunger  40  extends slightly into the space defined between the support plate  34  and the back-up plate  36 . Bolts  52  and locating pins  54  are used to secure the support plate  34  to the spacer plate  38 . The fixed pin  20  is secured between the support plate  34  and the back-up plate  36 . The fixed pin  20  and pressure pin assembly  18  are generally aligned with their central axes aligned horizontally as shown in the illustrated embodiment. 
     Referring to  FIGS. 3 and 5 , the spacer plate  38  has a top surface  70  that includes a plurality of sequencing holes  72 . The sequencing holes are adapted to receive a screw or pin that is matched to a recess (not shown) formed on the base of a template  12  so that the templates  12  are assured to be assembled to the desired bracket  10 . 
     Referring to  FIG. 5 , the bracket  10 , pressure pin assembly  18  and fixed pin  20  are shown assembled together. The crowned end  42  is shown extending inwardly from the support plate  34 . The pressure pin assembly  18  is assembled to the support plate  34  and extends outwardly from the support plate  34 . The fixed pin  20  is fixedly secured between the support plate  34  and the back-up plate  36 . The sequencing holes  72  may be used to receive a pin or screw to coordinate assembly of the desired template  12  to the bracket  10 . 
     Referring to  FIG. 6 , the bracket  10 , pressure pin assembly  18  and fixed pin  20  are shown assembled together. The crowned end  42  is shown extending inboard of the support plate  34 . The fixed pin  20  is shown extending between the support plate  34  and the back-up plate  36 . The spring clip retainer  66  is shown securing the pressure pin assembly  18  to the support plate  34 . 
     Referring to  FIG. 7 , the support plate  34  is shown with the pressure pin assembly  18  and fixed pin  20 . The bolts  52  and locating pins  54  are shown that are used to secure the support plate  34  to the spacer plate  38 , as shown in  FIGS. 1-6 . 
     Referring to  FIG. 8 , an alternative embodiment of a locking pin  80  is illustrated with the bracket  10  disclosed with reference to  FIGS. 1-7  above. The same reference numerals are used with the corresponding parts that are common to both embodiments. The locking pin  80  includes a plunger  82  that has an end surface  84  and a beveled ramp surface  86  on a distal end of the plunger  82 . The plunger  82  is telescopically received in a bore  90  defined by a plunger housing  92 . The plunger housing  92  is received within an opening  50  defined in the support plate  34 . The support plate  34  and back-up plate  36  are securely fastened together by means of bolts  52  and locating pins  54  that secure the back-up plate  36 , as shown in  FIG. 2 , to the spacer plate  38 . 
     The plunger housing  92  is inserted into the support plate  34  through the hole  50 . The plunger  82  is supported within the plunger housing  92  with the end surface  84  and the beveled ramp surface  86  extending inboard of the support plate  34 . A helical spring  94  is received about a T-shaped handle  96  that includes a shaft portion  98  and a handle portion  100 . The shaft portion  98  is inserted in the bore  90  and a hole  102  formed in the plunger housing  92 . The shaft portion  98  is secured in a hole  104  formed in the plunger  82 . 
     The spring  94  engages the plunger  82  about the shaft portion  98  on one end and on the other end engages a base  106  of the bore  90  formed in the plunger housing  92 . Pressure applied by the locking pin  80  is limited to a predetermined level established by the selection of the spring  94 . The spring force selected should permit the plunger  82  to be withdrawn by pulling the handle portion  100  with a controlled level of force that provides a rigid holding force. However, the level of force must be able to be easily overcome by pulling the handle portion  100 . 
     The handle portion  100  is received in a V-shaped recess  108  defined in the back end  110  of the plunger housing  92  when the plunger  82  is in a locking position. In the locking position, the plunger  82  may be received in the hole  24  formed in the template  12  to hold the template  12  in position as previously described with reference to  FIG. 1 . The handle portion  100  may be withdrawn and rotated to an unlocked position with the handle portion  100  held out of the V-shaped recess  108  to hold the plunger  82  retracted into the plunger housing  92 . If desired, a smaller recess (not shown) may be provided on the back end  110  of the plunger housing  92  to hold the handle portion  100  in the unlocked position. 
     The locking pin assembly  80  is secured to the support plate  34  by a spring clip retainer  66  that captures the support plate  34  between a rim  112  of the plunger housing  92  and the spring clip retainer  66  that is received in a slot  114  formed on the exterior of the plunger housing  92 . 
     Referring to  FIGS. 3 and 8 , the back-up plate  36  is secured by bolts  52  and locating pin  54  to the spacer plate  38 . Either the support plate  34  or back-up plate  36  may be disassembled from the spacer plate  38  when the locking pin assembly  80  is secured within the hole  50  provided in the support plate  34 . The plunger housing  92  is inserted from the inside of the support plate  34  into the hole  50 . The locking pin assembly  80  is secured on the outer side of the support plate  34  by the spring clip retainer  66 . Before assembling the locking pin assembly  80  to the support plate  34 , the plunger  92 , helical spring  94  and T-shaped handle  96  are assembled together and inserted into the plunger housing  92 . When the locking pin assembly  80  is assembled to the support plate  34 , the end surface  84  and the beveled ramp surface  86  of the plunger  82  extend slightly into the space defined between the support plate  34  and the back-up plate  36 . Bolts  52  and locating pins  54  are used to secure the support plate  34  to the spacer plate  38 . The fixed pin  20  is secured between the support plate  34  and the back-up plate  36 . The fixed pin  20  and locking pin assembly  80  are generally aligned with their central axes aligned horizontally as previously described. 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.