GB171762A - Improvements in dental hand piece - Google Patents

Abstract

171,762. Anzelewitz, A. Aug. 18, 1920. Chucks.-Relates to means for actuating the jaws of a double-coned chuck 17 in a dental handpiece of the type comprising a cylindrical casing, a hollow barrel member rotatably mounted therein and connected to a shaft attached to a torque driving cable, and which, at its forward end, forms a housing for the chuck, and comprises screw threads on the barrel which coact with screw threads on the shaft to produce relative rotation and longitudinal movement of the shaft and barrel to cause the chuck to grip or to release the tool. One construction, Figs. 2 and 6, comprises an exterior portion of the handpiece within which the cylindrical casing 16 is housed, one end of which extends beyond the exterior portion 15. Within the casing 16 is mounted the hollow barrel 18, which at its forward end houses the chuck 17, Fig. 2, and at its rear end is formed with screw threads for engagement with screw threads 24 formed on the shaft 21, the extended portion 28 of which is secured to the end of a torque driving cable. To operate the jaws of the chuck the shaft 21 is stopped and the operator grasps with one hand a collar 29 fast mounted on the barrel 18 and with the other hand pushes forward a member 39, against the action of a spring-pressed plunger 36, until teeth 38 on member 39 coact with a pin 25, whereupon the member 39 is rotated, thus causing relative rotation and longitudinal movement of members 18 and 21 to occur so as to release or clamp the jaws of the chuck. Between the forward end of the shaft 21 and the chuck closing members 19, and situated in recesses 22, 20 therein, is placed a spherical member 23 to ensure alignment of the chuck and shaft. In modified constructions the member 39 is replaced by a member permanently fast to the shaft 21.