Patent ID: 7771198
Filing Date: 2010-08-10
Classification: A61C

Abstract:
1. A set comprising a head for use with a handpiece of a contra-angle, and a dental instrument adapted for use with the head; wherein the instrument has an active part at a first end, and a handle at a second end of the instrument opposite to the first end; wherein the head has a body for receiving a shaft for transmitting rotational movement produced by a mechanical member associated with the handpiece, and a bore forming a housing for receiving the handle of the instrument; wherein the handle of the instrument includes a first rotary drive which, when mounted in the housing, is capable of meshing directly with a second rotary drive associated with the body of the head; wherein the first rotary drive is capable of retractable axial retention in the housing, independently of the second rotary drive; wherein the first rotary drive has a direction of rotation, the second rotary drive has a direction of rotation, and the direction of rotation of the first rotary drive is the same as the direction of rotation of the second rotary drive; wherein the first rotary drive includes a pinion capable of engaging a drive pinion located inside the body of the head, in the vicinity of the housing, and which is mounted on the shaft for transmitting the rotational movement produced by the mechanical member to the instrument, for causing rotational movement of the instrument; wherein the pinion of the first rotary drive has a profile, the second rotary drive includes the drive pinion located inside the body of the head, the drive pinion has a profile, and the profile of the pinion of the first rotary drive meshes with the profile of the drive pinion of the second rotary drive when the instrument is placed in the housing, and wherein the pinion of the first rotary drive and the drive pinion of the second rotary drive come into contact at bottom portions of the drive pinion of the second rotary drive; wherein the head is shaped to receive the instrument through an opening for insertion of the instrument into the housing so that the instrument is inserted through the opening by placing the head on the handle of the instrument; and wherein the head further includes a retractable retainer for engaging the handle of the instrument inserted through the opening, and wherein the retractable retainer includes a retention member which projects across the opening of the housing, and a ring coupled with the retention member and movable relative to the body of the head, against a restoring spring, wherein the ring is mounted concentrically on the body of the head.