1. Field of the Invention
This invention generally relates to set screws and, more particularly, to set screws of the "cup-point" type.
2. Description of the Prior Art
Set screws are used in various applications to removeably secure fly wheels, pinions, pulleys, cams, propellers and the like to shafts. In such applications, the set screws experience both vibrations and shock loads which might tend to loosen them.
Many set screw points have been designed in the past to increase the ability of the set screw to resist vibration. Examples of such set screws include: U.S. Pat. No. 1,330,792, Frick; U.S. Pat. No. 2,235,435, Koester; U.S. Pat. No. 2,245,525, Dicely; U.S. Pat. No. 2,462,910, Simmons; U.S. Pat. No. 2,778,265, Brown; U.S. Pat. No. 2,295,314, Whitney; U.S. Pat. No. 2,907,245, Whitson; U.S. Pat. No. 3,286,754, Klooz et al.; U.S. Pat. No. 3,419,058, Walker; and U.S. Pat. No. 3,920,060, Heldmann et al.
Of particular interest is U.S. Pat. No. 2,314,274, Hallowell, which discloses certain types of set screws having knurls on the work-engaging end wherein the work-engaging extremity is provided with centering means that will be effective to establish the position of the screw with the work prior to engagement of the interlocking means. Also, U.S. Pat. No. 2,992,669, Fesmire, discloses a certain knurled cup-point set screw wherein the cup is counter-bored Additionally, U.S. Pat. No. 4,764,068, Crispell, discloses a set screw having a threaded shank and a cup-point formed at one end of the shank wherein the cup-point has an outer frustoconical surface and an inner cylindrical surface which together define an annular wedge terminating in a circular edge. A portion of the outer frustoconical surface remote from the circular edge is provided with knurling.
Most of the above-mentioned prior art set screws have cup-point configurations formed by a machining process. However, none of these prior art references suggest the novel work-engaging end portion of the set screw of the present invention which can be formed by a forging process.