Metal working – Means to assemble or disassemble – Spring applier or remover
Reexamination Certificate
2000-03-24
2001-06-26
Hail, III, Joseph J. (Department: 3723)
Metal working
Means to assemble or disassemble
Spring applier or remover
C029S268000, C081S302000
Reexamination Certificate
active
06249946
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to tools for removing retaining rings, and more particularly, to a tool for removing internally and externally mounted retaining rings.
Retaining rings are commonly used in various industries to retain parts either within a cylindrical bore or on a cylindrical shaft. One type of retaining ring is a spiral retaining ring formed from one or more turns of flat wire which is wound in a spiral fashion upon itself to form multiple turns. The ends of the wire may include specially cut out portions that permit the ends to be grabbed by a pliers.
It is difficult to grab the free ends of the retaining rings due to the size of the bore and the clearance of the shaft. Further difficulty is encountered in that one of the free ends must be lifted from the remainder of the ring with a blunt object such as a screw driver or a fine point object, such as a dental pick, and then grabbed by the user so that the free ends and its turn may be unwound, further unwinding results in removal of the ring from the bore or shaft groove. Often these “pry-type” tools will slip out of engagement with the free end, frustrating the user and potentially causing injury when the pry tool becomes disengaged from the ring free end.
Various tools have been developed to remove snap rings and other types of rings. One of these tools, as described in U.S. Pat. No. 4,689,865 which issued Sep. 1, 1987, has a pliers-like body with two free ends that engage the free ends of the snap ring. This tool is complex and difficult to construct. It also can only be used in a perpendicular orientation with the snap ring. A similar tool is described in U.S. Pat. No. 5,212,859 issued May 25, 1993, whereupon the free ends of the tool are engaged with the free ends of the ring and then moved apart under the urging of the handles. The user must have sufficient clearance to attach the tool and to manipulate the handles of the tool.
U.S. Pat. No. 4,175,310 issued Nov. 27, 1979, describes a snap ring removal tool that does not use a pliers-type structure and thus can be operated with one hand from either the interior or exterior of a snap ring. However, the tool must be seated against either the interior of the bore or exterior of the shaft. If this contact is not maintained during the removal of ring, the tool can slip and lose its engagement with the free end of the snap ring.
U.S. Pat. No. 4,757,591 issued Jul. 17, 1988, describes a similar rotatable snap ring removal tool that incorporates a complex clamping end that first clamps the free end of a snap ring so that it may be removed from its groove and a separate pry tool inserted between the ring end and the bore. This construction is both complex and cumbersome.
These prior art tools all have various engagement and/or clamping ends for engaging free ends of single turn rings and they could not be easily adapted to engage a free end of a multiple turn ring. The present invention is therefore directed to a removal tool that can be easily operated with one hand and that is useful with both single turn and multiple turn retaining rings and which overcomes the aforementioned disadvantages.
SUMMARY OF THE INVENTION
It is accordingly, a general object of the present invention to provide a removal tool for a retaining ring that is operable with one hand and which is easily engaged with the free end of the retaining ring.
Another object of the present invention is to provide a retaining ring removal tool useful in removing multiple turn retaining rings from either bores or shafts, whenever the retaining rings have two free ends disposed on opposite sides of a body of the ring, the removal tool having a slotted end that engages the free end of the retaining ring.
Another object of the present invention is to provide a retaining ring removal tool having a handle portion and a ring engaging portion projecting therefrom, the ring-engaging portion having a flat surface formed on the exterior thereof that enables the ring engaging portion to be slid along the ring in order to engage one of the free ends of the ring.
A still further object of the present invention is to provide a removal tool for removing retaining rings and which is capable of one-handed operation, the tool having an engagement end with a slot disposed therein for receiving a free end of a retaining ring, the tool further having a flat surface for orienting the tool in a removal position on a retaining ring, the slot being spaced apart from the flat surface by a thin sidewall portion that may be interposed between the free end and a supporting turn of the retaining ring in order to engage and hold the free end so that it may be removed from the groove in which it lies.
Yet another object of the present invention is to provide a retaining ring removal tool that facilitates the removal of either flat or waved retaining rings from grooves on either shafts or in bores, the tool being capable of one-handed operation in either a vertical or horizontal work orientation, the tool having an engagement head with a slot formed therein for receiving the free end of the retaining ring, the slot being centrally disposed in the engagement head and a portion of the engagement head being truncated to define a flat surface of the tool proximate to the slot, but separated therefrom by a thin sidewall, the sidewall defining an interposing member fitting between the free end and an adjacent turn of the retaining ring.
These objects are accomplished through the structure of the present invention. In one embodiment of the invention, the tool includes a handle and an engagement member in the form of a removable bit. The bit has an overall circular cross-section that is partially truncated at the end thereof in order to define a flat, orientation surface of the tool. This flat surface permits the tool to be placed on a corresponding opposing flat surface of a retaining ring and moved into contact with the ring free end.
The engagement end further has a slot formed in it that defines a ring-receiving opening of the engagement end. The slot is spaced proportionate to the orientation surface so that a thin, but sufficiently strong sidewall is formed between the slot and the flat surface of the bit. This thin surface serves as a lead-in surface to guide the free end of the retaining ring into the slot. The thinness of the sidewall permits it to be easily interposed between adjacent turns of the ring at the end of the retaining ring.
In another embodiment of the invention, the engagement end may constitute an enlarged head portion at the end of the bit. This enlarged head portion also has a flat surface and slot. The bit may be angled at around 90° so that it may easily engage a retaining ring free end in situations where the circumferential clearance is reduced, but where there is sufficient axial clearance from its shaft with respect to the ring and the workpiece it is on. In yet another embodiment of the invention, the handle and engagement member may be formed as a single piece and machined from a single piece of metal. The material used for the tool is preferably hard, but slightly ductile, such as S7 tool steel, that may be hardened to a Rockwell Hardness Scale C of about Rc 51 to about Rc 58.
These and other objects, features and advantages of the present invention will be clearly understood through consideration of the following detailed description.
REFERENCES:
patent: 2835028 (1958-05-01), Wurzel
patent: 3305921 (1967-02-01), Morse
patent: 3365782 (1968-01-01), Madeira
patent: 4175310 (1979-11-01), Boyd
patent: 4689865 (1987-09-01), Chamblee
patent: 4757591 (1988-07-01), Hull et al.
patent: 5212859 (1993-05-01), Hagerty
patent: 5943754 (1999-08-01), Plite
patent: 1600944 (1990-10-01), None
Hail III Joseph J.
Shanley Daniel
Small Steel Ring Company
Vedder Price Kaufman & Kammholz
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