Patent ID: 11937989
Assignee: W&H DENTALWERK BüRMOOS GMBH
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 11:
12. A dental prophylactic treatment device comprising a dental prophylactic contra-angle handpiece for rotatably driving a dental tool which can be connected to the prophylactic contra-angle handpiece and which has a prophylactic treatment section, wherein the prophylactic contra-angle handpiece comprises:
a handle part extending along a longitudinal axis,
a head part adjoining the handle part, and
a tool holder rotatably disposed in the head part and extending along an axis of rotation, the longitudinal axis of the handle part and the axis of rotation of the head part being disposed at an angle to one another, wherein
the tool holder comprises a positive-locking chucking device configured to fix the tool shaft of the dental tool in a positive-locking manner, wherein the positive-locking chucking device comprises a holding element radially displaceable with respect to the axis of rotation of the tool holder, wherein
the holding element comprises a ring-shaped spring biased slide having an inner wall and an inner pass-through opening defined by the inner wall, wherein a wedge-shaped protrusion extends from the inner wall into the inner pass-through opening, wherein
the wedge-shaped protrusion is configured to engage in a recess on a tool shaft of the dental tool in order to secure the dental tool axially in the chucking device, and wherein
the wedge-shaped protrusion comprises a first inclined plane on the upper side thereof facing away from a tool-receiving opening of the prophylactic contra-angle handpiece and a second inclined plane on its underside facing the tool-receiving opening of the prophylactic contra-angle handpiece, wherein
the wedge-shaped protrusion is bounded by outer surfaces contained within a space defined by a projected intersection of the first inclined plane with the second inclined plane, wherein
each outer surface of the wedge-shaped protrusion which engages the recess on the tool shaft and contacts a surface of the recess when the tool shaft is arranged in the inner pass-through opening of the ring-shaped slide is a non-orthogonal outer face arranged non-orthogonally relative to the axis of rotation and wherein the prophylactic contra-angle handpiece has no pushing device for moving the holding element for releasing the dental tool from the tool holder.