Abstract:
An apparatus for removal of a windshield wiper arm or bracket and blade assembly from a threaded stud or shaft includes gripping jaws which are held in position by a cam that engages and pivots the arms into a desired gripping position. The apparatus further includes a central or axial shaft which may be rotated to drive a specially formed cup against the exposed wiper blade mounting shaft to thereby cause the jaws to move in a manner which will effect axial movement of the jaws and pulling of the wiper arm assembly from the mounting shaft or stud.

Description:
BACKGROUND OF THE INVENTION 
     In a principal aspect the present invention relates to a tool that is used to pull or remove windshield wiper arms from the driving shaft or stud of a wiper blade assembly. 
     Windshield wiper blades are typically mounted on a bracket which is attached to a reversibly rotating drive shaft or stud which reciprocates the bracket and attached blades back and forth over the windshield of a vehicle. The shaft or stud which drives the bracket and blade assembly typically projects outwardly from a vehicle body and comprises a tapered shaft with splines that fit into the bracket and blade assembly. The bracket and blade assembly is typically retained on the tapered spline and spline shaft by a bolt which attaches and mates with the threads on the end of the stud or shaft. 
     When repairing a vehicle, it is often necessary to remove the entire bracket and blade assembly from the drive shaft or stud. Removal of the bracket and blade assembly from the stud or shaft is often a difficult process because the bracket is wedged on the splined and tapered shaft. Using a lever bar to pry the bracket from the shaft or stud may not be desirable since the lever bar (e.g. Lisle Corporation wiper arm removal tool part 65750) may engage or impact on another part of the vehicle and cause damage. Pulling on the blade assembly is often not effective and is also quite difficult in most circumstances, particularly since the bracket and blade assembly may become corroded and thus fixed on the stud. Consequently, there has developed a need for providing a means to easily and effectively remove a windshield wiper bracket and wiper blade assembly from a stud or drive shaft of a windshield wiper assembly. 
     SUMMARY OF THE INVENTION 
     Briefly, the present invention comprises a puller device which includes a center rod or screw that is threadably and telescopically mounted in an outer, concentric screw. A yoke and a cone are mounted on the outer concentric screw. The cone may be translated axially on the outer screw and is shaped to engage pivotal arms mounted on the yoke. The pivotal, yoke arms each include a puller jaw at the extreme end thereof. The jaws are thus positioned on opposite sides of the center rod or screw. The center screw includes a handle which enables rotation of the center screw by grasping and turning the handle. The opposite end of the center screw includes a specially formed windshield wiper assembly stud engagement cup. The stud engagement cup includes a counterbore opening which is partially spherical in shape to avoid damaging the threads of a windshield wiper stud while simultaneously maintaining the cup centered on the stud so that as the center screw is turned, it will effectively elevate the gripping arms thereby withdrawing the bracket and blade assembly from the mounting stud or shaft. 
     Thus, it is an object of the invention to provide an improved puller apparatus for removal of a windshield wiper arm from a mounting shaft or stud. 
     It is a further object of the invention to provide a puller which may be utilized for windshield wiper arms and may also be utilized in other environments, for example, as a battery terminal cable puller. 
     Another object of the invention is to provide a puller device which provides a mechanical advantage that enables ease of operation, which is economical and which is rugged and sturdy. 
     These and other objects, advantages and features of the invention will be set forth in the detailed description which follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     In the detailed description which follows, reference will be made to the drawing comprised of the following figures: 
     FIG. 1 is a plan view of the windshield wiper arm puller illustrating its component parts including the stud engagement cup at the end of a threaded center shaft, rod or screw; 
     FIG. 2 is an exploded isometric view of the puller of FIG. 1; 
     FIG. 3 is an isometric view of the manner of operation of the puller to initially engage with a windshield wiper bracket; 
     FIG. 4 is an isometric view illustrating the operation of the puller device to remove the windshield wiper bracket from the stud or shaft on which it is mounted; and 
     FIG. 5 is an enlarged cross sectional view of the stud engagement cup which is incorporated in the puller apparatus of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the figures, it is noted that the construction of the puller apparatus of the invention comprises a modification of a prior art puller apparatus (Lisle Corporation battery terminal puller tool no. 54000) designed especially for removal of battery cables from battery terminals. With the present invention, the prior art construction has been utilized for a purpose distinct from that for which it was designed; namely, for removal of windshield wiper bracket and blade assemblies from their mounting stud or shaft. The prior art tool has also been modified to include a wiper blade assembly stud engagement cup  10  in FIG. 1 especially designed for use in combination with a puller mechanism so as to enable the use thereof efficiently with respect to windshield wiper arms or brackets in a manner which will avoid injury and which will significantly improve the effective use of the puller apparatus. 
     The apparatus, therefore, includes a center screw, rod or shaft  12  which is threaded substantially along its entire length and defines a center line axis  14 . A handle  16  is fitted through one end of the screw or shaft  12 . The puller further includes the stud engagement cup  10  attached to the opposite end of the shaft or screw  12 . As shown in FIG. 5, the shaft  12  includes a coaxial, reduced diameter, short rod section  18  which is peened to form a flange  20  to engage and retain the cup  10  as further described below. 
     Threadably mounted on the center screw or shaft  12  is an outer screw  24  which includes both inside and outside threads. A cone  26  with a conical surface  28  is threadably mounted on the outer screw  24 . A yoke  30  is likewise mounted on the outer screw  24 . The yoke  30  includes oppositely extending arms  32  and  34  with pivotally attached jaws  36  and  38  mounted thereon. The jaw  36  includes a follower  40  which engages surface  28 . The jaw  38  includes a follower  42  to also engage the conical surface  28 . Followers  40 ,  42  effect pivoting of the jaws  36  and  38  in response to engagement by surface  28 . 
     Jaw  36  further includes a gripping jaw tooth or member  46 . Similarly, the jaw or arm  38  includes a gripping jaw tooth or member  48 . As the jaws or arms  36  and  38  pivot about respective pivot axis  52  and  54 , which attach them to the yoke  30 , the jaws  46  and  48  may be driven inwardly toward one another as the conical surface  28  is threaded onto the outer screw  24  so as to approach the yoke  30 . 
     The stud engagement cup  10  is depicted in greater detail in FIG.  5 . It is depicted in cross sectional view in association with a typical windshield wiper drive shaft or stud  60 . The drive shaft or stud  60  includes the washer arm section  62 , a tapered spline  64  and a threaded section  66  designed to receive a nut (not shown) to hold a wiper bracket and blade assembly thereon. The threaded section  66  includes threads having a crest  68  and a valley  70 . The threaded section  66  terminates with a generally flat top face  72 . 
     The stud engagement cup  10  includes a spherical counterbore  80  which has a maximum diameter at the open end of the cup  10 . The spherical counterbore  80  is concentrically aligned and axially aligned on the center line axis  14 . Counterbore  80  then connects into a cylindrical counterbore  82  into which the flange  20  fits to retain the rod or screw  12 . Counterbore  82  connects with a lesser diameter counterbore  84  receiving rod section  18  to facilitate the retention of the center screw  12  as previously described. 
     In operation, the cup  10  is formed to prevent destruction or damage to the threads on the end of the threaded stud  68 . Because of the spherical or arcuate shape of the counterbore  80 , the threads are not damaged by engagement thereby and the shape of the counterbore effectively precludes deformation of the outer end of the stud  60 . Further, the shape of the cup  10 , and more particularly, the counterbore  80 , maintains the cup  10  centrally located on the stud  60  thereby enhancing the effectiveness and uniform pulling by the puller when attempting to remove a windshield wiper bracket and blade assembly from the shaft  60 . 
     FIGS. 3 and 4 illustrate in greater detail the mode of operation of the puller. As depicted, the cup  10  is aligned over the top of the shaft or stud  60 . The jaws  46  and  48  are fitted under the wiper blade assembly and cause it to move toward the center line axis  14  by screwing the cone  26  in a manner which drives the arms  36  and  38 . Thereafter, the handle  16  is turned to effect turning of the center screw or rod  12  causing it to engage tightly against stud or shaft  60  and transporting the arms  36  and  38  and the wiper blade assembly upwardly axially from the shaft  60 . 
     The cup  10 , and more particularly, the configuration of the cup  10  insures that the wiper blade arm assembly can be easily removed without damaging the threads on the shaft  60  so that the wiper arm assembly may be replaced as necessary. Additionally, because of the configuration of the cup  10 , and more particularly the generally spherical or arcuate counterbore  80 , the assembly remains properly centered over the end of variously sized studs so that the pulling force on the wiper blade arms  36 ,  38  is uniform thereby avoiding damage to that wiper arm assembly and the stud threads and thereby preventing slippage of the puller from the assembly. 
     Among the more important features of the invention is the configuration shape and construction of the cup  10  for the function of and structural reasons described. It is possible, however, to vary the construction somewhat. For example, a spherical shape is depicted in the drawings as defining the counterbore  80 . Other arcuate shapes may be utilized including a frustoconical type counterbore configuration. The preferred configuration is an arcuate or a spherical type configuration in cross section. Thus, while there has been set forth a preferred embodiment of the invention, it is to be understood that their invention is to be limited only by the following claims and equivalents thereof.