Abstract The disclosure relates to a radial tooth lock washer, with either internal or external teeth, which is arranged for sealing relationship with a screw head or nut and an underlying surface. The sealing facility takes the form of a short section of heatshrinkable, usually thermoplastic tubing positioned concentrically about the lock washer and heat shrunk so that portions of the tubing lie over the upper and lower principal surfaces of the lock washer. When the screw is tightened down on the lock washer, the heat-shrunk sealing material serves as an effective annular seal surrounding the threaded portion of the screw and the threaded opening in which it is received. In the case of washers with internal radial teeth, the annular seal is effective to fully enclose the lock washer itself. In the case of a washer with external teeth, the dimensions of the heat shrunk tubing are such that portions thereof extend inward beyond the annular region of the teeth to form a positive seal around the screw shank. In addition, an extremely efficient, although perhaps less positive, seal is provided in the area of the lock washer teeth themselves. The invention is also directed in part to a novel method and means for assembling the new self-sealing lock washer, whereby the washers may be produced on a high speed, fully automated basis and at an economically realistic cost level.
The method of making a self-sealing radial tooth lock washer, which comprises a. supplying a radial tooth lock washer having teeth thereon being twisted to extend beyond opposed axial end faces of the washer, b. positioning over said washer in generally concentric relation thereto a tubular section of heat-shrinkable elastomeric material, c. positioning said tubular section with its axial ends projecting substantially axially beyond the principal surfaces of said washer formed by its axial end faces, and. d. subjecting said washer to heat thereby constricting the tubular section by effecting radial shrinkage thereof, whereby portions of said tubular section intermediate its ends are brought into tightly constricted radially compressing relation to the outer peripheral edges of the washer, e. and constricting the radially shrunk tubular section end portions during the heating, thereby causing said end portions to overly in juxtaposition the opposed axial faces of the washer.
Claim 2
Independent Claim
147 words
The method of making a self-sealing radial tooth lock washer, which comprises a. supplying a radial tooth lock washer having teeth thereon being twisted to extend beyond opposed axial end faces of the washer, b. positioning over said washer in generally concentric relation thereto a tubular section of heat-shrinkable elastomeric material, c. positioning said tubular section with its axial ends projecting substantially axially beyond the principal surfaces of said washer formed by its axial end faces, and. d. subjecting said washer to heat thereby constricting the tubular section by effecting radial shrinkage thereof, whereby portions of said tubular section intermediate its ends are brought into tightly constricted radially compressing relation to the outer peripheral edges of the washer, e. and constricting the radially shrunk tubular section end portions during the heating, thereby causing said end portions to overly in juxtaposition the opposed axial faces of the washer.
Claim 3
Dependent Claim
35 words
The method of claim 1, further characterized by a. said heat-shrinkable material comprising a heat-shrinkable elastomer, and b. said elastomer is exposed to said heat while being held in predetermined concentric relation to said washer.
Claim 4
Dependent Claim
51 words
The method of claim 2, further characterized by a. said tubular section having been radially expanded to have a ratio of expanded diameter-to-recovered diameter of at least about 2 to 1, and b. sAid tubular section having an expanded internal diameter not substantially greater than the external diameter of said washer.