Improvements in percussive dental instruments

Abstract

Abstract 379,444. Percussive dental instruments. LEVY, D. D., 506, Fort Washington Avenue, New York, U.S.A. June 24, 1931, No. 18290. [Class 124.] A percussive dental instrument for cutting or chiseling teeth or tamping fillings comprises a non-circular rotary driving shaft 23, a spring- actuated hammer slidable thereon and having an undercut screw thread 21 thereon ending in blank cylindrical surfaces 20, 25, and a spring- operated pawl 16 which normally rides on the surface 20 but engages the screw thread when pressure is put upon the tool 8 and so causes the hammer to be retracted to compress the spring 34. When the pawl has reached the blank end 25 of the hammer, it is held out of action by a trip finger 161 and allows the hammer to descend and strike the tool shaft 9. The slidable trip finger 161 is pressed forward to engage the pawl 16 by means of a spring 36 which however is held out of action by the hammer after this has descended and until it is slightly retracted by pressure on the tool. The tool 8 is formed with a stud 8<1> sliding in a slot 71 in the shaft 9 and is held in place by means of a quick-release clip 40 pivotally mounted by means of its inturned ends 41 seated in sockets on the shaft and having a transverse portion 42 engaging the stud 8<1>. The intensity of the hammer blows may be varied by varying the size or tension of the spring 34 or the weight of the hammer. Packings 14, 33 seal the casing against moisture and thus permit sterilization.

Inventors

No inventors recorded.

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