Linear motion device having an anti-twist safeguard, comprising an elongate anti-friction lining

• US 9,151,372 B2
• Filed: 10/19/2012
• Issued: 10/06/2015
• Est. Priority Date: 10/20/2011
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Keller, Bernhard
• Primary Examiner(s): Krause, Justin
• Application Number:
  US13/656,576
• Publication Number:
  US 20130098185A1
• Time in Patent Office: 1,082 Days
• Field of Search: 74/892.3, 74/893.2, 74/893.3, 74/893.7, 384/26, 384/42
• US Class Current: 1/1
• CPC Class Codes: F16H 2025/204 Axial sliding means, i.e. for rotary support and axial guiding of nut or screw shaft
• CPC Class Codes: F16H 25/20 Screw mechanisms with automatic reversal F16H25/12
• CPC Class Codes: F16H 25/24 Elements essential to such mechanisms, e.g. screws, nuts F16H25/22 takes precedence
• CPC Class Codes: Y10T 74/18576 including screw and nut

Abstract

A linear motion device includes a housing, an extension arm, and an anti-twist safeguard. The extension arm projects from the housing and includes a securing section. The anti-twist safeguard includes at least one separate elongate anti-friction lining, which is formed with a constant cross-sectional shape. The anti-friction lining is arranged substantially without play between the housing and the securing section of the extension arm and extends transversely to a longitudinal axis. The extension arm is supported on the housing in such a way that it can move along the longitudinal axis. In the securing section, the extension arm extends parallel to the longitudinal axis with a constant external cross-sectional shape deviating from a circular shape. The anti-twist safeguard engages positively in said external cross-sectional shape, thus securing the extension arm with respect to the housing against twisting relative to the longitudinal axis.

Claims

1. A linear motion device comprising:

a housing;

an extension arm, which projects from the housing and includes a securing section; and

an anti-twist safeguard including at least one separate elongate anti-friction lining, which is formed with a constant cross-sectional shape, the anti-friction lining being arranged substantially without play between the housing and the securing section of the extension arm and extending transversely to a longitudinal axis,

wherein the anti-friction lining comprises a strip having a first longitudinal end and a second longitudinal end, the strip extending longitudinally around a circumference of the extension arm to position the first longitudinal end and the second longitudinal end at positions where the first longitudinal end and the second longitudinal end are arranged facing each other and spaced apart from each other to define a free space therebetween,

wherein the extension arm is supported on the housing in such a way that the extension arm is configured to move relative to the housing along the longitudinal axis,

wherein in the securing section, the extension arm extends parallel to the longitudinal axis with a constant external cross-sectional shape deviating from a circular shape, and

wherein the anti-twist safeguard engages positively in said external cross-sectional shape, thus securing the extension arm with respect to the housing against twisting relative to the longitudinal axis.

2. The linear motion device according to claim 1, wherein the cross-sectional shape of the anti-friction lining is of substantially rectangular design.

12. The linear motion device according to claim 1, wherein the free space is sized to accommodate expansion of the anti-friction lining about the longitudinal axis from a first length of the anti-friction lining to a second length of the anti-friction lining without contact between the first end and the second end.

13. The linear motion device according to claim 12, wherein the first end and the second end are positioned nearly adjacent to one another when the anti-friction lining is expanded to the second length.

3. A linear motion device, comprising:

a housing;

an extension arm, which projects from the housing and includes a securing section; and

an anti-twist safeguard including at least one separate elongate anti-friction lining, which is formed with a constant cross-sectional shape, the anti-friction lining being arranged substantially without play between the housing and the securing section of the extension arm and extending transversely to a longitudinal axis,

wherein the anti-friction lining comprises a strip having a first longitudinal end and a second longitudinal end, the strip extending longitudinally around a circumference of the extension arm to position the first longitudinal end and the second longitudinal end at positions where the first longitudinal end and the second longitudinal end are arranged facing each other and spaced apart from each other to define a free space therebetween,

wherein the extension arm is supported on the housing in such a way that the extension arm is configured to move relative to the housing along the longitudinal axis,

wherein in the securing section, the extension arm extends parallel to the longitudinal axis with a constant external cross-sectional shape deviating from a circular shape,

wherein the anti-twist safeguard engages positively in said external cross-sectional shape, thus securing the extension arm with respect to the housing against twisting relative to the longitudinal axis, and

wherein the linear motion device further includes a plurality of substantially identical anti-friction linings arranged adjacent to one another along the longitudinal axis.

4. The linear motion device according to claim 3, wherein the free spaces respectively defined between the first and the second ends of each of the anti-friction linings are arranged in different locations when viewed in the direction of the longitudinal axis.

5. The linear motion device according to claim 3, wherein all the anti-friction linings are fixed on a separate holding part.

6. The linear motion device according to claim 5, further comprising:

an end seal having at least one sealing lip surrounding the extension arm in a sealing manner, the end seal being secured on the separate holding part.

7. The linear motion device according to claim 6, further comprising:

a foam wiper arranged adjacent to the end seal on the side of the at least one anti-friction lining, the foam wiper resting on the extension arm.

8. The linear motion device according to claim 5, further comprising:

an elongate threaded spindle supported in the housing in such a way that the threaded spindle is configured to rotate relative to the longitudinal axis; and

a nut in screw engagement with the threaded spindle and being secured on one longitudinal end of the extension arm.

9. The linear motion device according to claim 8, further comprising:

at least one end stop for the nut, said at least one end stop being composed of an elastomer, the at least one end stop being secured on the holding part.

10. The linear motion device according to claim 9, wherein the at least one end stop is constructed in the form of a hollow cylinder which surrounds the extension arm.

11. The linear motion device according to claim 5, wherein:

the housing includes a circular-cylindrical housing tube,

the holding part is constructed in the form of a hollow cylinder, and

the housing tube surrounds the holding part at least in one section or sections.

14. A linear motion device with an elongated extension arm configured to move along a longitudinal axis, the extension arm having a constant external cross-sectional shape deviating from a circular shape, the linear motion device comprising:

a housing; and

an anti-twist safeguard including a separate lining element, the separate lining element comprising a strip formed with a constant cross-sectional shape and having a first and second longitudinal end, the strip extending longitudinally around a circumference of the extension arm to position the first and second longitudinal ends with respective end faces of the first and second longitudinal ends arranged facing each other and spaced apart from each other to define a circumferential gap therebetween, the lining element being arranged substantially without play within the housing and extending circumferentially about the longitudinal axis,

wherein the anti-twist safeguard engages positively in the external cross-sectional shape so as to (i) secure the extension arm with respect to the housing against twisting relative to the longitudinal axis and (ii) allow the extension arm to move relative to the housing along the longitudinal axis.