Metal working – Method of mechanical manufacture – Process for making bearing or component thereof
Reexamination Certificate
1998-06-09
2001-04-10
Hughes, S. Thomas (Department: 3726)
Metal working
Method of mechanical manufacture
Process for making bearing or component thereof
C029S256000, C029S266000, C029S426500
Reexamination Certificate
active
06212775
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
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.
2. Description of the Prior Art
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 left 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.
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.
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.
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 and 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 a blind hole.
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 from those previously proposed.
SUMMARY OF THE INVENTION
According to our present invention we have provided a blind hole bushing puller comprising a drawing portion comprising: a rectangular cross block having a first end-portion and a second end portion and a pair of elongated leg screws a securement portion comprising, a circular bushing insert, and a connection portion comprising a bolt with a matching washer and a nut. Each of the end-portions of the cross block have a threaded leg hole formed therethrough, the cross block also has a centrally located unthreaded cross block hole. One of the leg screws passes through one of the threaded leg holes, and the other leg screw passes through the other threaded leg hole. The bushing insert has a centrally located unthreaded bushing insert hole and is sized to snugly fit about an inside diameter of the bushing. The bolt is sized to pass through the bushing insert hole and the cross block hole with a head of the bolt being positioned adjacent an upper portion of the bushing insert. The bolt head is sized slightly larger than the bushing insert hole and has a sufficient length so as to allow a lower portion of the bolt to extend beyond a lower end of the cross block hole. The bolt is securable to the cross block by the washer and the nut. Whereby when the bushing insert is securely attached within the bushing and the bolt is secured through the bushing insert and the cross block, the leg screws can be tightened in a direction wherein an upper portion of the leg screws comes into engagement with a housing portion supporting the bushing. The leg screws can then be further tightened in an alternating fashion thereby pulling and eventually removing the bushing from the hole.
We have further provided a blind hole bushing puller as described above, wherein each of the leg screws has a hexagonal head at a lower end thereof, wherein the leg screws can be tightened by engaging the hexagonal heads.
Still another feature of our invention concerns the blind hole bushing puller as described above, wherein each of the leg screws has a leg end pivotally positioned at an upper end thereof, the leg ends having a flat upper surface for engagement with a housing portion supporting a bushing that is to be removed.
Still yet another feature of our invention concerns the blind hole bushing puller as described above, wherein the bushing insert includes a key stock securely attached at an upper surface thereof, the key stock being positioned on the bushing insert in such a location so as to prohibit the bolt head from turning when the bolt has been inserted all the way through the bushing insert, thereby allowing a user to securely tighten the bolt to the cross block.
Yet another feature of our invention concerns the blind hole bushing puller as described above, wherein the distance between the pair of elongated leg screws is adjustable so as to provide for the removal of various sized bushings.
A still further feature of our invention concerns the method for pulling a bushing from a blind hole comprising the steps of: a) providing a bushing puller of the type described above; b) placing the bolt through the bushing insert hole of the bushing insert; c) securely attaching the bushing insert within the bushing with the bolt head being positioned within the bushing and a lower portion of the bolt extending outside of the bushing; d) attaching the cross block to the lower portion of the bolt by passing the lower portion of the bolt through the centrally located unthreaded hole in the cross block and securing the cross block to the bolt by placing the washer and the nut onto the bolt; e) tightening the leg screws in a direction wherein an upper portion of the leg screws comes into engagement with a housing portion supporting the bushing; and f) further tighten the leg screws in an alternating fashion to pull and remove the bushing from the blind hole.
An even further feature of our invention concerns the method described above, wherein the bushing insert is securely attached within the bushing by welding the bushing insert to the bushing.
Other objects, features and advantages of our invention will become more readily apparent upon reference to the following description when taken in conjunction with the accompanying drawings, which drawings illustrate several embodiments of my invention.
REFERENCES:
patent: 1493534 (1924-05-01), Hardin
patent: 2253411 (1941-08-01), Thompson
patent: 2650419 (1953-09-01), Barbisch
patent: 4207664 (1980-06-01), Zoula
patent: 4471517 (1984-09-01), Denmeade et al.
patent: 4473933
Decker Wayne D.
Sarver Garry A.
Fulcrum Tools, Inc.
Hughes S. Thomas
Leydig , Voit & Mayer, Ltd.
Omgba Essama
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