Length-measuring device and method for assembling the same

• US 10,488,190 B2
• Filed: 07/31/2017
• Issued: 11/26/2019
• Est. Priority Date: 09/12/2016
• Status: Active Grant

• Current Assignee: Dr. Johannes Heidenhain GmbH
• Original Assignee: Dr. Johannes Heidenhain GmbH
• Inventors: Schweikl, Konrad
• Primary Examiner(s): Guadalupe-McCall, Yaritza
• Application Number:
  US15/663,857
• Publication Number:
  US 20180073869A1
• Time in Patent Office: 848 Days
• Field of Search: 33706
• CPC Class Codes: G01B 21/02 for measuring length, width, or thickness G01B21/10 takes precedence
• CPC Class Codes: G01D 11/245 Housings for sensors
• CPC Class Codes: G01D 5/24438 Special design of the sensing element or scale
• CPC Class Codes: G01D 5/34769 Sealing means

Abstract

A length-measuring device includes a hollow section member having a scale disposed therein. The hollow section member has a slot which extends along the scale, wherein, during position measurement, a drive dog of a scanning unit scanning the scale extends through the slot. The slot is sealed by an elastic seal extending along the hollow section member. A sleeve is attached to at least one end of the seal in a pull-off resistant manner. The sleeve has an axial abutment which is effective in a longitudinal direction of the hollow section member and with which the sleeve bears axially against the hollow section member.

Claims

1. A length-measuring device, comprising:

a hollow section member having a scale disposed therein, the hollow section member having a slot which extends along the scale, wherein, during position measurement, a drive dog of a scanning unit scanning the scale extends through the slot, the slot being sealed by an elastic seal extending along the hollow section member; and

a sleeve attached to at least one end of the seal in a pull-off resistant manner, the sleeve having an axial abutment which is effective in a longitudinal direction of the hollow section member and with which the sleeve bears axially against the hollow section member.

2. The length-measuring device as recited in claim 1, wherein the seal extends along the hollow section member from a first end to a second end, wherein the sleeve is attached to each of the two ends of the seal, and wherein the seal is disposed in a stretched state along the hollow section member by each one of the sleeves being attached to a respective one of the two ends of the seal in a pull-off resistant manner and the abutment of each of the sleeves bearing axially against the hollow section member at a respective end thereof.

3. The length-measuring device as recited in claim 1, wherein the pull-off resistant connection between the sleeve and the seal is formed by at least one inwardly directed projection of the sleeve that penetrates into the seal.

4. The length-measuring device as recited in claim 3, wherein the at least one projection has a first shape extending in the longitudinal direction and a second shape facing in an opposite direction to the longitudinal direction, the first shape forming a ramp that allows the sleeve to be pushed onto the seal in the longitudinal direction, and the second shape providing a resistance that prevents the sleeve from being displaced relative to the seal in the opposite direction, such that the at least one projection forms the pull-off resistant connection between the seal and the sleeve.

5. The length-measuring device as recited in claim 3, wherein the sleeve has a plurality of the inwardly directed projections that are spaced apart in the longitudinal direction and penetrate into the seal.

6. The length-measuring device as recited in claim 1, wherein the sleeve has a slot, and the seal is a sealing lip including a longitudinally extending bead and a lip integrally formed therewith, the sleeve embracing the bead, and the lip extending through the slot of the sleeve into the slot of the hollow section member.

7. The length-measuring device as recited in claim 1, wherein the sleeve is disposed in a groove or bore extending along the hollow section member.

8. The length-measuring device as recited in claim 7, wherein the sleeve has a slot, and the seal is a sealing lip including a longitudinally extending bead and a lip integrally formed therewith, the sleeve embracing the bead, and the lip extending through the slot of the sleeve into the slot of the hollow section member, the bead of the sealing lip radially preloading the sleeve such that the sleeve is elastically resiliently urged along a circumference of the sleeve against an inner surface of the groove or bore of the hollow section member.

9. The length-measuring device as recited in claim 7, wherein the abutment of the sleeve is a radially outwardly directed flange of the sleeve.

10. A method for assembling a length-measuring device, comprising:

providing a hollow section member having a longitudinally extending slot through which a drive dog of a scanning unit scanning a scale disposed within the hollow section member extends during position measurement;

providing an elastic seal with which the slot is sealable;

attaching a sleeve to at least one end of the seal in a pull-off resistant manner, the sleeve having an axial abutment which is effective in a longitudinal direction of the hollow section member; and

then

positioning the sleeve on the hollow section member such that the abutment of the sleeve bears axially against the hollow section member.

11. The method as recited in claim 10, wherein the positioning of the sleeve on the hollow section member is accomplished by pushing the sleeve into a longitudinally extending groove or bore of the hollow section member from an end face at an end of the hollow profile section.

12. The method as recited in claim 10, wherein the sleeve has at least one inwardly directed projection that has a first shape extending in the longitudinal direction and a second shape facing in an opposite direction to the longitudinal direction, the first shape forming a ramp that allows the sleeve to be pushed onto the seal, and the second shape providing a resistance that prevents the sleeve from being displaced relative to the seal in the opposite direction, the pull-off resistant connection between the seal and sleeve being created by pushing the sleeve onto the seal in the longitudinal direction such that the at least one projection penetrates into the seal.