# US 8,783,785 B2 · Chisel holder having a weld as a wear protection element

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- Number: US 8,783,785 B2
- Document ID: US8783785B2
- Status: Granted
- Kind: B2
- Application number: 13/061,790
- Filed: 2009-07-10
- Published: 2011-08-25
- Granted: 2014-07-22
- Earliest claimed: 2008-09-05
- Assignees: Wirtgen GmbH
- Applicants: Thomas Lehnert; Christian Berning; Martin Lenz
- Inventors: Thomas Lehnert; Christian Berning; Martin Lenz
- Web page: https://patentgrep.com/patent/US8783785B2

## CPC

- E21C 35/183: with inserts or layers of wear-resisting material {(drill bits with wear-resistant parts E21B10/46)}
- E21C 35/1831: {Fixing methods or devices}
- E21C 35/1835: {Chemical composition or specific material}
- E21C: MINING OR QUARRYING

## Abstract

The invention relates to a bit holder (20) for a cutting machine, road milling machine, surface miner, or the like, having a bit receptacle (29) that comprises an introduction opening, and having a bit supporting surface (26), at least one wear protection element (40) being arranged in a region associated with the bit supporting surface (26). In order to bring about effective wear protection with little outlay in a bit holder of this kind, provision is made according to the present invention that the at least one wear protection element is embodied as a weld (40), and is arranged at least locally in at least one recess (41).

## Claims

### Claim 1

A bit holder, comprising:
a bit holder body having a bit supporting surface defined on the bit holder body and having a bit receptacle defined in the bit holder body, the bit receptacle being communicated with the bit supporting surface at an introduction opening, the bit holder body having a first recess defined entirely in the bit supporting surface; and
a first weld at least partially filling the first recess such that the first weld does not extend above the bit supporting surface, the first weld being formed of a uniform continuous filler metal material having a higher resistance to abrasion than does the bit supporting surface, the first weld forming a first wear protection element operably associated with the bit supporting surface so that as the bit supporting surface is worn away the wear protection element is also worn away.

### Claim 2 (depends on 1)

The bit holder of claim 1, wherein:
the bit receptacle has a longitudinal center axis; and
the first recess is concentric about the longitudinal central axis.

### Claim 3 (depends on 2)

The bit holder of claim 2, further comprising:
a second recess formed in the bit supporting surface concentric with the first recess; and
a second weld at least partially filling the second recess.

### Claim 4 (depends on 1)

The bit holder of claim 1, wherein:
the weld terminates flush with the bit supporting surface.

### Claim 5 (depends on 1)

The bit holder of claim 1, wherein:
the weld has an exposed surface set back from the bit supporting surface so that some initial wear of the bit supporting surface occurs before the weld begins to be worn away.

### Claim 6 (depends on 1)

The bit holder of claim 1, wherein:
the bit receptacle has a longitudinal center axis; and
the first recess includes regions having different radial spacings from the longitudinal center axis.

### Claim 7 (depends on 1)

The bit holder of claim 1, wherein:
the first recess includes a bottom wall and two parallel side walls.

### Claim 8 (depends on 1)

The bit holder of claim 1, wherein:
the first recess includes a bottom wall and two side walls forming a V-shape cross-section.

### Claim 9 (depends on 1)

The bit holder of claim 1, wherein:
the first recess has a semi-circular cross-section.