Title:
Hand-held power tool
Kind Code:
A1


Abstract:
A hand-held power tool includes a shaft (12) located in the housing part (11) of the power tool (10), a bearing (13) for rotatably supporting the shaft (12) in the housing part (11), and a snap-receptacle (14) formed in the housing part (11) for receiving the bearing (13).



Inventors:
Erhardt, Jochen (Klosterlechfeld, DE)
Mascall, Eric (Shanghai, CN)
Application Number:
11/985301
Publication Date:
05/15/2008
Filing Date:
11/13/2007
Primary Class:
International Classes:
E21B3/00
View Patent Images:
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Primary Examiner:
NASH, BRIAN D
Attorney, Agent or Firm:
ABELMAN, FRAYNE & SCHWAB (NEW YORK, NY, US)
Claims:
What is claimed is:

1. A hand-held power tool, comprising a housing part (11); a shaft (12) located in the housing part (11); a bearing (13) for rotatably supporting the shaft (12) in the housing part (11); and a snap-receptacle (14) formed in the housing part (11) for receiving the bearing (13).

2. A hand-held power tool according to claim 1, wherein the snap-receptacle (14) comprises a cylindrical chamber (18) for receiving the bearing (13), and at least two snap members (15) circumferentially arranged about the receiving chamber (18).

3. A hand-held power tool according to claim 2, wherein the snap receptacle (14) has bead-shaped ribs (17) provided on respective free ends of the snap members (15) and projecting radially inwardly.

4. A hand-held power tool according to claim 2, wherein the snap-receptacle comprises at least one stop (16) defining an insertion depth of the bearing (13) in the receiving chamber (18).

5. A hand-held power tool according to claim 1, wherein the snap receptacle (14) is provided at an opening (19) of the housing part (11).

Description:

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hand-held power tool such as, e.g., a drilling, percussion-rotary or a screwdriving tool, and including a housing part, a shaft located in the housing part, and a bearing for rotatably supporting the shaft in the housing part.

2. Description of the Prior Art

German document DE 33 13 656 discloses a hand-held drilling and rotary-percussion power tool including a bearing for rotatably supporting a drilling spindle and located at an opening formed in the tool housing. The spindle bearing is arranged in a cylindrical housing section and is supported in an axial direction against a step formed in the housing. In the opposite direction, adjacent to the drill chuck, the bearing is supported by an additional annular member which is secured with a safety ring.

This method of securing a shaft bearing in the housing complicates the assembly of the power tool and, thus, is associated with increased assembly costs.

British document GB 2 276 214 discloses a bearing mount for retaining a rolling bearing in the tool housing opening with the bearing being retained by an intermediate polypropelene bush. The polypropylene bush engages the bearing from behind with a circumferential lip.

The drawback of the bearing mount of the British reference consists in complicated and, therefore, expensive assembly. First, the bush should be mounted in the housing and only then, the bearing can be inserted into the bush. The tool costs are also increased by additional costs associated with manufacturing of the propylene bush.

Accordingly, an object of the present invention is to provide a hand-held power tool in which the shaft supporting bearing is easily mounted and, consequently, the assembly costs are reduced.

SUMMARY OF THE INVENTION

These and other objects of the present invention, which will become apparent hereinafter, are achieved by providing, in the power tool housing, a snap receptacle for receiving the shaft bearing. The snap receptacle insures an easy and cost-effective mounting of the shaft bearing and its securing in the tool housing, without use of any additional parts. The snap receptacle can, e.g., be formed in the housing during injection-molding of the housing part.

Advantageously, the snap-receptacle has a cylindrical chamber for receiving the bearing, and at least two snap members circumferentially arranged about the receiving chamber. The snap members insure their easy formation during the production of the injection-molded component on one hand, and on the other hand, provide for an easy insertion of the bearing into the receiving chamber of the receptacle.

Advantageously, bead-shaped ribs are provided on respective free ends of the snap members. The bead-shaped ribs extend radially inwardly and engage the bearing from behind in the axial direction, securing the bearing in the receptacle.

Advantageously, the receptacle includes at least one stop defining an insertion depth of the bearing in the receiving chamber. The stop secures the bearing axially in the direction opposite the bead-shaped ribs.

Advantageously, the snap receptacle is provided at the opening formed in the housing part, which insures an easy mounting and securing of the bearing for the shaft which is formed as a spindle and projects from the housing part opening.

The novel features of the present invention which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiment, when read with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings show:

FIG. 1 a cross-sectional view of a portion of a hand-held power tool with a shaft bearing receptacle according to the present invention; and

FIG. 2 a cut-out II in FIG. 1 at an increased, in comparison with FIG. 1, scale.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A hand-held power tool 10, which is shown in FIG. 1 and is formed as a percussion-rotary tool, includes a housing part 11, a shaft 12 which is formed as a spindle of a rotary-percussion mechanism, and a bearing 13 that rotatably supports the shaft 12 in the housing part 11. The shaft 12 projects from the housing part 11 through an opening 19 formed in the housing part 11. The housing part 11 forms a snap receptacle which is generally designated with a reference numeral 14, for the shaft bearing 13. The snap receptacle 14 has a cylindrical receiving chamber 18, a stop 16 that is arranged transverse to the axial extent of the receiving chamber 18 and is formed as a step, and at least two snap members 15. The snap members 15 are circumferentially arranged over the cylindrical receiving chamber 18 and are provided, on their free ends, with bead-shaped ribs 17 which project in the direction of the shaft 12. The snap members 15 are preferably bent about the receiving chamber 18 and form an interrupted ring. The receiving chamber 18 forms an integral part of the housing part 11 and can be formed therewith, e.g., by an injection-molding process. A compression spring 20 biases the shaft 12 or the spindle in a direction away from the bearing 13 in order to displace the shaft 12, which is received in the bearing 13 with a slide fit, back to its position in which the shaft is capable of performing a percussion-rotary operation.

During the assembly of the hand-held power tool 10, the bearing 13 can be pushed into the snap-receptacle 14 by slightly bending the snap members 15 radially outwardly, whereby upon a complete push of the bearing 13 up to the stop 11, the snap members 15 snap back, with the bead-shaped ribs 17 lying behind the bearing 13 securing the bearing 13 against the displacement in the direction away from the stop 18.

Though the present invention was shown and described with references to the preferred embodiment, such is merely illustrative of the present invention and is not to be construed as a limitation thereof and various modifications of the present invention will be apparent to those skilled in the art. It is therefore not intended that the present invention be limited to the disclosed embodiment or details thereof, and the present invention includes all variations and/or alternative embodiments within the spirit and scope of the present invention as defined by the appended claims.