# US 2019/0168369 A1 · Hand-held power tool

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- Number: US 2019/0168369 A1
- Document ID: US20190168369A1
- Status: Published application
- Kind: A1
- Application number: 16/324,233
- Filed: 2017-07-31
- Published: 2019-06-06
- Earliest claimed: 2016-08-09
- Assignees: Hilti Aktiengesellschaft
- Applicants: Hilti Aktiengesellschaft
- Inventors: Stefan HAMMERSTINGL; Eduard PFEIFFER; Matthias DOBERENZ; Pierre PALMER
- Web page: https://patentgrep.com/patent/US20190168369A1

## CPC

- B25D 11/005: {Arrangements for adjusting the stroke of the impulse member or for stopping the impact action when the tool is lifted from the working surface}
- B25D 17/06: Hammer pistons; Anvils {; Guide-sleeves for pistons}
- B25D 16/00: Portable percussive machines with superimposed rotation {, the rotational movement of the output shaft of a motor being modified to generate axial impacts on the tool bit (combined percussion and rotary drilling adapted for earth drilling E21B6/00)}
- B25D 2217/0019: Guide-sleeves
- B25D 2217/0023: Pistons
- B25D 2250/035: Bleeding holes, e.g. in piston guide-sleeves
- B25D: PERCUSSIVE TOOLS {(percussive machines for forging B21J; hand-held drilling machines, in general B23B45/00, for wood B27C3/08; drilling machines, used for mining or quarrying, with reciprocating tool which is turned intermittently when out of contact with the working face E21B1/00)}

## Abstract

The A hand-held power tool includes a tool holder 2 for holding a tool and a pneumatic striking mechanism for periodically generating impacts on the tool held in the tool holder. The striking mechanism includes a guiding tube, an exciter piston, a striker, a pneumatic chamber closed by the exciter piston and the striker in the guiding tube, and a compensating opening in the guiding tube for ventilating the pneumatic chamber. A cap covers the compensating opening on an outside of the guiding tube. The cap is open in an opening direction which is largely tangential to the guiding tube.

## Claims

### Claim at position 1

1-11. (canceled)

### Claim 12

A hand-held power tool comprising:
a tool holder for holding a tool;
a pneumatic striking mechanism for periodically generating impacts on the tool held in the tool holder, the pneumatic striking mechanism including a guiding tube, an exciter piston, a striker, a pneumatic chamber closed by the exciter piston and the strike in the guiding tube and a compensating opening in the guiding tube for ventilating the pneumatic chamber; and
a cap covering the compensating opening on an outside of the guiding tube, and the cap is open in an opening direction tangential to the guiding tube.

### Claim 13 (depends on 12)

The hand-held power tool as recited in claim 12 wherein the cap is formed by a bulge of the guiding tube.

### Claim 14 (depends on 12)

The hand-held power tool as recited in claim 12 wherein the cap is open due to a recess tangential to the guiding tube.

### Claim 15 (depends on 14)

The hand-held power tool as recited in claim 14 wherein the cap has exactly one recess.

### Claim 16 (depends on 12)

The hand-held power tool as recited in claim 12 wherein an underside of the cap facing the pneumatic chamber seamlessly transitions into an inner surface of the guiding tube.

### Claim 17 (depends on 12)

The hand-held power tool as recited in claim 12 wherein the cap has a spherical shape.

### Claim 18 (depends on 17)

The hand-held power tool as recited in claim 17 wherein a radius of curvature of the cap corresponds to a radius of the compensating opening.

### Claim 19 (depends on 12)

The hand-held power tool as recited in claim 12 wherein the cap deflects a flow course from the compensating opening by at least 45 degrees.

### Claim 20 (depends on 12)

The hand-held power tool as recited in claim 12 wherein the guiding tube has additional radial openings, and the compensating opening having a smallest flow cross section of the compensating opening and the additional radial openings.

### Claim 21 (depends on 12)

The hand-held power tool as recited in claim 12 wherein the compensating opening is situated at a tool-side reversing point of the movement of the exciter piston.

### Claim 22 (depends on 12)

The hand-held power tool as recited in claim 12 further comprising a carrier tube, the guiding tube being situated in the carrier tube, the cap being situated in a channel between the carrier tube and the guiding tube.