Rotary tool for machining workpieces

• US 6,267,595 B1
• Filed: 04/06/2000
• Issued: 07/31/2001
• Est. Priority Date: 04/12/1999
• Status: Expired due to Term

• Current Assignee: Edenta AG Dentalprodukte Switzerland
• Original Assignee: Edenta AG Dentalproducte
• Inventors: Grätz, Dieter
• Primary Examiner(s): Wilson, John J.
• Application Number:
  US09/544,541
• Time in Patent Office: 481 Days
• Field of Search: 433/165, 433/166
• US Class Current: 433/165
• CPC Class Codes: A61C 3/02 Tooth drilling or cutting instruments; Instruments acting like a sandblast machine

Abstract

A rotary tool for material detaching work, especially in dentistry, comprising a machining portion having an outer circumferential surface coated with a nickel layer in which diamond particles are embedded, is characterized in that the nickel layer and the diamond particles protruding from it are covered by a layer of chromium nitride. The duration of the tool is considerably increased by the chromium nitride layer.

Claims

1. A rotary machining tool for use in the field of dentistry, comprising:

(a) a clamping shaft portion (3);

(b) a cylindrical machining head portion (1) arranged collinearly relative to said shaft portion, said head portion having a first end adjacent said clamping shaft portion, and a rounded second end remote from said clamping shaft portion;

(c) a neck portion (2) connecting said head portion first end with said shaft portion;

(d) a layer of nickel (4) covering at least the cylindrical circumferential surface of said head portion;

(e) a plurality of diamond particles (5) embedded in said nickel layer, said particles being in contiguous engagement with said head portion cylindrical surface and protruding outwardly from said nickel layer; and

(f) a layer of chromium nitride (6) completely covering the protruding portion of said diamond particles and the external surface of said nickel layer, said chromium nitride layer having a thickness of from 1 to 4 μ

m, whereby said chromium nitride layer fills the uneven surface structure of the diamond particles as well as any gaps separating said nickel layer and said diamond particles.

2. A rotary machining tool as defined in claim 1, wherein said clamping shaft portion has a diameter between 1.0 and 4.0 mm;

and further wherein said neck portion is tapered radially inwardly in the direction of said machining head-portion.

3. A rotary machining tool as defined in claim 2, wherein the length of the tool is between 10 mm and 60 mm.