Patent Publication Number: US-6904664-B1

Title: Work-piece positioner and method

Description:
The present application is a divisional application of U.S. patent application Ser. No. 10/244,205, filed on Sep. 16, 2002, which is currently pending. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to a workpiece positioner, and more particularly to a positioner for supporting and positioning a motorcycle fender. 
   2. Discussion of Related Art 
   During manufacture of a vehicle, for example a motorcycle, it is often necessary for a vehicle body part to be supported so that a person can assemble, grind, prepare, paint, or otherwise work on the body part. Devices for supporting the body part during the manufacture process are commercially available. Some of these devices are rigid stands. Generally, rigid stands do not allow for positioning and repositioning of the body part. It is sometimes desirable to position and reposition the body part for comfort, convenience or efficiency. 
   Other devices include an adjustable stand that can allow the body part to be positioned and repositioned. The adjustable stand can be unbalanced by the weight of the body part and the force applied to the part, which can be significant. 
   In addition, efficiency can decrease if mounting, positioning and repositioning the body part is time intensive, difficult and cumbersome. It is desirable to increase efficiency by reducing the time, the degree of difficulty, and ease with which the body part is mounted, positioned, and repositioned. 
   SUMMARY OF THE INVENTION 
   The present invention is directed toward a workpiece holder or positioner that is easily adjustable to conveniently re-orient the workpiece while securely locking the workpiece in a desired orientation. In accordance with the present invention, the positioner includes a cantilever arm that defines a first axis and has a first end and a second end. A support arm defines a second axis and has a first end and a second end. The support arm is attached to the second end of the cantilever arm. A mounting head receives the workpiece and is attached to the second end of the support arm. The support arm is selectively rotatable around the second axis, and the cantilever arm is selectively rotatable around the first axis. In accordance with one aspect of the invention, a counterweight is attached to the support arm to counterbalance the weight of the workpiece. 
   In accordance with another aspect of the invention, a first brake assembly engages the cantilever arm to releasably secure the cantilever arm against rotation around the first axis. A second brake assembly is operable to engage the support arm to releasably secure the support arm against rotation around the second axis. A brake actuator assembly communicates with the first and second brake assemblies and is manually operable to engage and disengage the first and second brake assemblies. When the brakes are disengaged, the cantilever arm and support arm are free to rotate about their longitudinal axes and thereby permit reorientation or repositioning of the workpiece. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and further features of the invention will be apparent with reference to the following description and drawings, wherein: 
       FIG. 1  is an elevated perspective view of a positioner in accordance with a first embodiment of the invention; 
       FIG. 2  is a schematic front view of the positioner of  FIG. 1  with a fender mounted thereon; 
       FIG. 3  is a schematic front view of the positioner shown in  FIG. 2 ; and 
       FIG. 4  is a schematic top view of the positioner shown in  FIG. 2 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to the drawings, a workpiece positioner  100  for positioning a workpiece, for example a motorcycle fender  102 , according to a first embodiment of the invention is illustrated. The positioner  100  supports the fender  102  ( FIG. 2 ) so as to orient the fender  102  in a desired position. The fender  102  can be worked on in the desired position and may be selectively repositioned, as described further hereinafter. 
   The positioner  100  includes a base plate  104 , a base leg  106 , a cantilever arm  120 , a first brake assembly  122 , a support arm  130 , a second brake assembly  132 , and a mounting head  138 . 
   The cantilever arm  120  defines a longitudinal or first axis  142  and is adapted to rotate around the first axis  142 . The support arm  130  defines a longitudinal or second axis  152  and is adapted to rotate around the second axis  152 . As will be appreciated, the first axis  142  is generally horizontal while the second axis  152  is generally perpendicular to the first axis. 
   The base plate  104  is sufficiently wide so as to provide stability to the positioner  100  during operation. If desired, the base plate  104  can be bolted to a floor so as to further increase the stability of the positioner  100 . 
   The base leg  106  is generally vertical and has a first or lower end  204  secured to the base plate  104  and a second or upper end  208  secured to a housing of the first brake assembly  122 . The base plate  104  and base leg  106  are immovably affixed to one another and cooperate to define a base of the positioner  100 . The base leg  106  is immovably affixed to the housing of the first brake assembly  122  so as to retain the first brake assembly  122  in a fixed location relative to the base plate  104 . The base leg  106  is offset relative to a center of the base plate  104  to provide a counterbalancing force to the cantilever arm  120 , as illustrated. 
   The cantilever arm  120  is generally horizontal, that is, parallel to the base plate  104  and perpendicular to the base leg  106 , and has a first end  220  and a second end  222 . The first end  220  of the cantilever arm is received within the first brake assembly  122 , while the second end of the cantilever arm  120  is affixed to the second brake assembly  132  such that the second brake assembly  132 , support arm  130 , and mounting head  138  move together with the cantilever arm  120  as it is rotated upon release or disengagement of the first brake assembly  122 , described hereinafter. 
   The support arm  130  has a first end  230  rotatably received within the second brake assembly  132  and a second end  232  secured to the mounting head  138 . As will be appreciated from the foregoing, the support arm  130  is adapted to rotate with the cantilever arm  120  around the first axis  142 , as well as about its longitudinal axis, referred to herein as the second axis  152 . Accordingly, the support arm  130  can be rotated out of the generally vertical orientation illustrated in the drawing figures. 
   As will be appreciated by those skilled in the art, each of the first and second brake assemblies  122 ,  132  include bearings or similar structures by means of which the cantilever arm  120  and support arm  130 , respectively, are secured thereto for rotation around their longitudinal axes  142 ,  152 . The first and second brake assemblies  122 ,  132  also include brake mechanisms that are adapted to engage the cantilever arm  120  and support arm  130 , respectively, to secure the arms against undesired rotation. Such brakes can take on any of several functionally equivalent forms. For example, the portions of the cantilever and support arms  120 ,  130  disposed within the first and second brake assemblies  122 ,  132 , respectively, may include radially extending flanges (not shown) that may be frictionally engaged by brake pads (not shown) of the first and second brake assemblies  122 ,  132 . Such brake pads may be air, hydraulic, or mechanically actuated. Alternatively, the brake assemblies  122 ,  132  may include band-type clamping structures that are movable into and out of frictional engagement with the circumference of the cantilever arm  120  and support arm  130 . Again, the actuating mechanism for such band-type clamping structures may be any known in the art. Therefore, due to the fact that braking assemblies suitable for use in the present construction are well known to those skilled in the art, and may be used interchangeably, the specific structure of the braking assemblies will not be described further hereinafter. 
   The first brake assembly  122  engages the cantilever arm  120  to releasably secure the cantilever arm  120  in a desired position. When the first brake assembly  122  is disengaged, the cantilever arm  120  is free to rotate around the first axis  142 . Similarly, the support arm  130  is rotatably secured to the second brake assembly  132  such that, upon disengagement of the second brake assembly  132 , the support arm  130  is free to rotate around the second axis  152  to permit desired repositioning of the support arm  130  and the mounting head  138 . 
   A brake actuator assembly  340  includes an actuator or foot pedal  342 , a first hose  344 , and a second hose  346 . The first hose  344  extends from the actuator  342  to the first brake assembly  122 . The second hose  346  extends from the actuator  342  to the second brake assembly  132 . The actuator  342  is connected to a pressurized fluid source (not shown) and controls the delivery of pressurized fluid to the first and brake assemblies  122 ,  132 . More specifically, when the actuator  342  is depressed, pressurized fluid is supplied to the first and second brake assemblies  122 ,  132  via the first and second hoses  344 ,  346 , causing the brakes to disengage and permitting the cantilever arm  120  and support arm  130  to rotate about their axes  142 ,  152 . Similarly, release of the actuator  342  cuts off fluid pressure the first and second brake assemblies  122 ,  132  (preferably also directing fluid within the hoses  344 ,  346  to atmosphere, if air, or to a recollection circuit, if liquid, via a bleed valve), and causes the brakes to re-engage and lock the cantilever arm  120  and support arm  130  against further rotation. 
   As noted from the foregoing, in a preferred embodiment, the brakes  122 ,  132  are normally engaged, and are biased toward the engaged position so as to prevent rotation about the respective axes  142 ,  152  upon the loss of fluid pressure. Actuating the brake actuator disengages the brakes  122 ,  132  so as to allow rotation about the respective axes  142 ,  152 . Although brakes employing fluid pressure (i.e., air, hydraulic) are used in this example, purely mechanical braking systems and methods are known to those of ordinary skill in the art and may be substituted therefor. 
   The mounting head  138  is preferably rigidly affixed to the second end  232  of the support arm  130  and is operable to receive and support the fender  102 . Specifically, the mounting head  138  has two rigid pins  240 ,  242  and two retractable, spring-loaded pins  244 ,  246  that engage the fender  102 . Because the mounting head  138  is attached to support arm  130 , the mounting head  138  can be rotated around both the first axis  142  and the second axis  152 . 
   The fender  102  has an elongated fender body  148  that defines four apertures  250 ,  252 ,  254 ,  256 , each of which is adapted to receive one of the pins  240 ,  242 ,  244 ,  246 . The rigid pins  240 ,  242  are fixed and can extend through the corresponding apertures  250 ,  252  defined by the fender  102 . The retractable pins  244 ,  246  are spring-loaded and can be moved against the spring bias into a retracted position. In the normal or extended position, the retractable pins  244 ,  246  extend through the corresponding apertures  254 ,  256 . 
   Alternative embodiments include differing numbers of pins, and some of the pins include differing biasing means. For example, the differing biasing means can include hydraulic and electrical biasing means. Naturally, the apertures  250 ,  252 ,  254 ,  256  are provided in the fender  102  to facilitate eventual mounting to a motorcycle, so the number, arrangement, and position of the pins  240 ,  242 ,  244 ,  246  will, to some extent, be customized to each object to be held by the device. 
   Preferably, a counterweight  290  is attached to the housing of the second brake assembly  132  and extends in a direction opposite to that of the support arm  130 . The counterweight  290  is of sufficient weight to counterbalance the fender  102 . 
   During operation, the first and second brake assemblies  122 ,  132  are engaged so as to lock the cantilever arm  120  and support arm  130  and, hence, the mounting head  138 , in position. The fender  102  is mounted on the mounting head  138 . Specifically, the fender body  148  is oriented so that the apertures  250 ,  252  align with the corresponding pins  240 ,  242 . The fender body  148  is moved relative to the mounting head  138  so that the pins  240 ,  242  extend through the apertures  250 ,  252 . The spring pins  244 ,  246  retract or move inwardly against the bias of the springs until the corresponding fender body apertures  254 ,  256  are aligned therewith, at which point the spring pins  244 ,  246  snap through the apertures  254 ,  256  to secure and releasably mount the fender  102  onto the mounting head  138 . 
   If the fender  102  needs to be repositioned, the actuator  342  is depressed to disengage the first and second brake assemblies  122 ,  132 . The fender  102  is then grasped and moved to reposition it as desired while the counterweight  290  helps balance the fender  102  and facilitate repositioning thereof. When the fender  102  is in a desired position, the actuator  342  is released. Releasing the actuator  342  re-engages the brakes  122 ,  132  and locks the arms  120 ,  130  in position and, thus, secures the fender  102  in the desired orientation so that work can be conveniently performed on the fender  102 . 
   In alternative embodiments, the first and second brake assemblies are individually engaged and disengaged. Also, relative movement around the various axes may be controlled by a brake assembly controller. In yet other embodiments, none, one or more than three air brakes and corresponding hoses are used. Further, alternative brake types are used, for example, mechanical, hydraulic, and electrical brake types as well as alternative means of communication and control of the brakes are contemplated. It is also contemplated that the mounting head will be adjustably secured to the support arm to permit further angular adjustment of the fender position. Naturally, the connection between the support arm  130  and the mounting head  138  may include a mechanical lock or a third brake assembly, similar to the first and second brake assemblies  122 ,  132 , to selectively control reposition of the mounting head  138  about the support arm  130 . 
   The embodiments described herein are examples of structures, methods, and systems having elements corresponding to the elements of the invention recited in the claims. This written description may enable those skilled in the art to make and use embodiments having alternative elements that likewise correspond to the elements of the invention recited in the claims. The intended scope of the invention thus includes other structures, methods and systems that do not differ from the literal language of the claims, and further includes other structures, methods, and systems with insubstantial differences from the literal language of the claims.