Patent Publication Number: US-2002010996-A1

Title: Method and apparatus for installing and removing bearing races

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS  
     [0001] This patent application is a continuation of copending U.S. patent application Ser. No. 09/491,031, filed Jan. 25, 2000, [pending], the entire disclosure of which is incorporated by reference, which is a continuation-in-part of copending U.S. patent application Ser. No. 09/094,134, filed Jun. 9, 1998, [pending], the entire disclosure of which is also hereby incorporated by reference. 
    
    
     
       FIELD OF THE INVENTION  
       [0002] The present invention relates generally to a new and improved method and apparatus for pulling bushings or bearings. More specifically the present invention provides a method and apparatus for pulling bushings or bearings quickly and easily from a hole wherein the bushing or bearing is tightly positioned within the hole and requires special tools and/or methods for removing the bushing or bearing from the hole, particularly when the bushing or bearing is situated in a blind hole. For reference purposes, the term bushing will be used synonymously with the term bearing since the method and apparatus of the present invention applies to the removal of both bushings and bearings similarly situated.  
       BACKGROUND OF THE INVENTION  
       [0003] Various types of bushings and bearings can be frequently mounted in situations where the bushing can only be accessed from one side, this is commonly known as a blind hole. Often times, as in the case of a standard bushing used for a tree spade, there is no space lieft behind the bushing in order to leverage a damaged bushing from the hole. Furthermore, conventional type bushing pullers, even blind hole bushing pullers cannot pull bushing from a blind hole if there is no gap present behind the bushing, or if there is no bushing mount so as to grab the bushing with standard type bushing pullers.  
       [0004] The conventional method of removing a bushing that is press fit into a blind hole would be to cut off the back end or grease cap of the blind hole with a torch. After the back end of the blind hole is cut off, then the damaged bushing is then carefully cut lengthwise with a torch, while at the same time being careful so as to not damage the bushing boss supporting the bushing. The damaged bushing can then be forced out from the back end with a tool and/or a hammer. After the bushing is removed, the lining within the bushing boss would need to be inspected for damage and properly cleaned before a new bushing can be inserted. Furthermore, the grease cap or the back end of the blind hole would need to be welded back on and a new bushing can then be inserted.  
       [0005] The entire procedure of removing the damaged bushing using this conventional method can take approximately 30 minutes to an hour for each damaged bushing. This can place a machine that uses multiple bushings out of service for a few days. We have therefore provided a bushing removal tool and method that can remove damaged bushings quickly and easily in about five minutes without a concern of causing any other damage to the bushing boss supporting the bushing.  
       [0006] There have been various types of bushing and bearing pullers available in the marketplace, but none have gained widespread acceptance because of their difficulty of use and the inability for quickly an easily removing bushing or bearings, particularly from a blind hole. In addition, other types of bushing pullers require additional time to remove the bushing/bearing, do not provide flexibility and ease of use of our puller and do not employ the particular method that we have developed in removing bushings and bearings from a bushing boss or a hole, especially when the bushing/bearing is situated in blind hole.  
       [0007] These and other types of pullers used in the past do not offer the flexibility and inventive features of our method and apparatus for pulling bushings and bearings. As will be described in greater detail hereinafter, the method and apparatus of the present invention differs form those previously proposed.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008] It has recently been realized concept disclosed in the present invention can be implemented in a wider variety of applications for a variety of press fit parts including for example bearing races (as disclosed herein), bearing cups as is demonstrated in U.S. patent application Ser. No. 09/491,031 (the entire disclosure of which is hereby incorporated by reference), wheel studs of truck wheel hubs, to name a few. The invention resolves long felt needs for easier installation and removal of press fit parts. The invention is applicable to both installation and removal of press fit parts. Moreover, the invention can be used not only to pull press fit parts but also to push press fit parts with the tool. For example, in the case of wheel studs, the wheel studs may be directly connected to the cross block by screwing the threaded end of the wheel stud into a central hole of the cross block between the leg screws or more preferably by extending the threaded end of the wheel stud through a central hole in the cross block between leg screws and threadingly connecting or attaching the threaded end of the wheel stud to a nut that engages the opposite side of the support body of the cross block (on the side opposite the head end of the wheel stud). Depending upon the way in which the leg screws are turned, the wheel studs can either be pushed or pulled with the tool.  
       [0009] This patent application is intended to tie the many applications together with broad and meaningful patent coverage sufficiently generic to cover more of the various applications. Accordingly the present invention is directed toward a method of translating a press fit part in a cavity defined in an apparatus. The method comprises arranging a tool on the apparatus. The tool includes a cross block and spaced apart leg screws. The leg screws threadingly engage the cross block. The cross block is attached to the press fit part at a location between the leg screws along a longitudinal axis such that the cross block is substantially aligned on a traverse axis perpendicular to the longitudinal axis. After the attaching and arranging step, the first and second leg screws are alternately actuated causing the cross block to rock about a traverse axis and translate the press fit part along the longitudinal axis relative to the cavity. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0010] The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:  
     [0011]FIG. 1 is an exploded perspective view of our bushing puller embodying important features of our invention;  
     [0012]FIG. 2 is a cross-sectional side view of our bushing puller prepared to pull a bushing from a bushing boss or a hole;  
     [0013]FIG. 3 is a top plan view of the bushing puller insert used in our invention;  
     [0014]FIG. 4 is a side view of our bushing puller insert shown in FIG. 3;  
     [0015]FIG. 5 is a partial cross-sectional side view illustrating the positioning of our bushing puller insert within a bushing that is to be pulled from a hole;  
     [0016]FIG. 6 is a cross-sectional side view illustrating our method of pulling a bushing from a hole using our bushing pulled;  
     [0017]FIG. 7 is a cross-sectional side view further illustrating our method of pulling a bushing from a hole using our bushing puller;  
     [0018]FIG. 8 is a cross-sectional side view illustrating how a bushing is finally removed from a hole using our bushing puller and method;  
     [0019]FIG. 9 is an exploded perspective view of another embodiment of our bushing puller illustrating further important features of our invention wherein our bushing puller is adjustable for pulling bushings of varying sizes; and  
     [0020]FIG. 10 is a side view of our bushing puller shown in FIG. 9  
     [0021] While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0022] Referring now to the drawings, FIGS. 1 and 2 show our bushing/bearing puller  10  used for pulling a bushing  11  and/or a bearing from a blind hole  12 . Our bushing puller  10  comprising: a rectangular cross block  14  having a first end-portion  16  and a second end portion  18 , a pair of elongated leg screws  20 ,  22 , a circular bushing insert  24 , and a bolt  26  with a matching washer  28  and a nut  30 .  
     [0023] Each of the end-portions  16 ,  18  of the cross block  14  have a threaded leg hole  32 ,  34  formed therethrough, and a centrally located unthreaded cross block hole  36  all of which are aligned along a longitudinal axis  100 . The cross block  14  can be made of steel, aluminum or any other type of material durable and strong enough to perform the function of pulling a bushing tightly secured within a blind hole.  
     [0024] Each of the leg screws  20 ,  22  passes through and is threadingly engaged with one of the threaded leg holes  32 ,  34 . The bushing insert  24  has a centrally located unthreaded bushing insert hole  38  and is sized to fit snugly about an inside diameter  5  of the bushing  11 . The bolt  26  is sized to pass through the bushing insert hole  38  and the cross block hole  36  with a head  40  of the bolt being positioned adjacent an upper portion of the bushing insert  24 .  
     [0025] The bolt head  40  is sized slightly larger than the bushing insert hole  38  and has a sufficient length so as to allow a lower portion of the bolt  26  to extend beyond a lower end of the cross block hole  36 . The bolt  26  is securable to the cross block  14  by the washer  28  and the nut  30 . When the bushing insert  24  is securely attached within the bushing  11  and the bolt  26  is secured through the bushing insert  24  and the cross block  14 , the leg screws  20 ,  22  can be tightened in a direction wherein an upper portion of the leg screws comes into engagement with a housing portion  42  supporting the bushing  11 . The leg screws  20 ,  22  can then be further tightened in an alternating fashion thereby pulling and eventually removing the bushing  11  from the hole  12 .  
     [0026] In order to pull a 2 ½ inch bushing from a blind hole, excellent results can be obtained when: the cross block  14  is made of steel being one inch thick, two inches wide and six inches long, the threaded leg holes have a {fraction (9/16)} inch diameter with a ⅝ inch thread (18 threads per inch), and the unthreaded cross block hole has a {fraction (9/16)} inch diameter; and the bushing insert  24  is ½ inch thick with a {fraction (9/16)} inch center hole, and the diameter is sized to be approximately 0.002 inches less than the inner diameter of the bushing, with a tolerance of +/−0.0001 inches.  
     [0027] In order to make it easy to tighten the leg screws  20 ,  22  with a high impact wrench  44  or a standard wrench, we have provided hexagonal heads  46 ,  48  on the ends of the leg screws. We have also provided leg ends  50 ,  52  that are pivotally positioned at an upper end of the leg screws  20 ,  22 . The leg ends  50 ,  52  are designed to have a flat upper surface for engagement with the housing portion  42  supporting the bushing  11  that is to be removed from the blind hole  12 .  
     [0028] In order to tightly secure the bolt  26  through the bushing insert  24  and the cross block  14 , we have alternatively added key stock  54  (FIGS.  3 - 5 ) that is securely attached at an upper surface of the bushing insert  24 . The key stock  54  can be secured in place with a weld  56 . The key stock  54  is positioned on the bushing insert  24  in such a way so as to prohibit the bolt head  40  from turning when the bolt  26  has been inserted all the way through the bushing insert  24 , thereby allowing a use to securely tighten the bolt  26  to the cross block  14 , thereby keeping the bolt from unnecessarily rotating as one is trying to tighten the bolt  26  down.  
     [0029] FIGS.  6 - 8  illustrate our method of using our bushing puller  10  for pulling a worn bushing  11  from a socket or a blind hole  12  on a tree spade. First a threaded bolt  26  is extended through the bushing insert  24 . Then the bushing insert  24  is welded  58  to the bushing. A bushing removal tool  10  is then secured to the bolt. Alternative forces are then applied, first to the tree spade  42  at one side of the worn bushing  11  and then another force to second and opposite side of the worn bushing  11 . This process of applying alternating forces is repeated to rock the cross block  14  about a first transverse axis  102  that is perpendicular to the longitudinal axis  100  and simultaneously translate the cross block  14  linearly along a second transverse axis  104  that is mutually perpendicular with the longitudinal axis  100  and first transverse axis  102  until the worn bushing  11  is displaced from the tree spade socket  12 . A new bushing can then be inserted into the tree spade socket to complete the reconditioning of the tree spade.  
     [0030] More specifically, FIGS.  6 - 8  illustrate how the bushing  11  is walked out when the leg screws  20 ,  22  are tightened in an alternating fashion to pull and remove the bushing  11  from the blind hole  12 . FIG. 6 shows how the bushing  11  is slightly pulled from the blind hole  12  and the cross block  14  is slightly angled in relationship to the housing  42  supporting the bushing  11  as the leg screw  20  is tightened. FIG. 7 shows the next step how the bushing  11  is pulled even more from the blind hole  12 , and the cross block  14  is now slightly angled the other way in relationship to the housing  42  as the leg screw is tightened. FIG. 8 finally shows how the bushing  11  is finally removed from the blind hole  12  as the leg screws  20 ,  22  have been tightened in a continuous alternating fashion so as to “walk out” the bushing  11  from the blind hole  12 .  
     [0031] Excellent results can be obtained when the bushing insert  24  is securely attached within the bushing  11  by welding  58  the bushing insert  24  directly to the bushing  11 . It is generally common for facilities or businesses that perform repairs on equipment that requires a replacement of press fit bushings to have a welding gun readily available for use.  
     [0032] We have also provided a modified version of our bushing puller in order to accommodate the removal of bushings of various sizes. As can be seen in FIGS. 9 and 10, this bushing puller  60  has adjustable leg hole inserts  62 ,  64  that are sized to engage a widened ridged hole  66 ,  68  so as to allow for adjustment of the spread of the leg screws  70 ,  72 .  
     [0033] As various possible embodiments may be made in the above invention for use for different purposes and as various changes might be made in the embodiments and method above set forth, it is understood that all of the above matters here set forth or shown in the accompanying drawings are to be interpreted as illustrative and not in a limiting sense.  
     [0034] All of the references cited herein, including patents, patent applications, and publications, are hereby incorporated in their entireties by reference.  
     [0035] The foregoing description of various embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Numerous modifications or variations are possible in light of the above teachings. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitle