Tensioning device

Patent metadata

Field	Value
Publication number	US-11041549-B2
Application number	US-201816159860-A
Country	US
Kind code	B2
Filing date	Oct 15, 2018
Priority date	Oct 24, 2017
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

A tensioning device for tensioning a traction mechanism of a belt drive comprises a base member; a first tensioning arm pivotably supported on the base member and carrying a first tensioning roller; a second tensioning arm pivotably supported on the base member and carrying a second tensioning roller; a spring arrangement with first and second springs arranged to be effective between the first and second tensioning arms; wherein the two tensioning arms, when being pivoted relative to each other within a first tensioning angle range, are force-loaded against each other by the first spring, wherein the second spring is force-free relative at least to one of the tensioning arms; and wherein the tensioning arms, when being pivoted relative to each other within a second tensioning angle range comprising larger tensioning angles than the first tensioning angle range, are force-loaded against each other by the first spring and the second spring.

First claim

The invention claimed is:

1. A tensioning device for tensioning a traction mechanism of a belt drive, comprising:
a base member;
a first tensioning arm, pivotably supported on the base member and carrying a first tensioning roller;
a second tensioning arm, pivotably supported on the base member and carrying a second tensioning roller;
a spring arrangement with a first spring and a second spring arranged to be effective between the first and the second tensioning arm;
wherein the two tensioning arms, when pivoted relative to each other within a first tensioning angle range, are force-loaded against each other by the first spring, wherein the second spring is force-free relative to at least one of the two tensioning arms; and
wherein the two tensioning arms, when pivoted relative to each other within a second tensioning angle range comprising larger tensioning angles than the first tensioning angle range, are force-loaded against each other by the first spring and additionally by the second spring.

2. The tensioning device according to claim 1 ,
wherein the second spring is supported with a first spring end against the first tensioning arm in a first rotational direction;
wherein the second spring at tensioning angles within the first tensioning angle range is supported with a second spring end in the opposite second rotational direction against the first tensioning arm; and
wherein the second spring in the second tensioning angle range is support-free relative to the first tensioning arm and is supported against the second tensioning arm in the second rotational direction.

3. The tensioning device according to claim 1 ,
wherein a first tensioning angle is formed within the first tensioning angle range in a balanced position between the first tensioning arm and the second tensioning arm; and
wherein a second tensioning angle is formed between the first tensioning angle range and the second tensioning angle range, at which second tensioning angle a resulting spring force acting on the tensioning arms increases abruptly.

4. The tensioning device according to claim 3 , wherein the second tensioning angle is smaller than the sum of the first tensioning angle plus 20°.

5. The tensioning device according to claim 1 , wherein the second spring is mounted with a preload.

6. The tensioning device according to claim 3 ,
wherein the first spring, at the largest tensioning angle of the first tensioning angle range, generates a first spring force between the two tensioning arms; and
wherein the second spring, at the smallest tensioning angle of the second tensioning angle range, generates a second spring force between the two tensioning arms that is larger than a third of the first spring force.

7. The tensioning device according to claim 3 , wherein adjustment means are provided for adjusting the first tensioning angle range.

8. The tensioning device according to claim 3 , wherein the second spring has a guiding portion formed between the second spring end and the second support portion, by which guiding portion the second spring is axially supported and guided relative to a support element of the second tensioning arm when the two tensioning arms are pivoted within the first tensioning angle range.

9. The tensioning device according to claim 1 , further comprising a damper arranged to dampen an abutment movement of the second spring end of the second spring against the first tensioning arm.

10. The tensioning device according to claim 1 , wherein the second spring is accommodated in a telescope-retainer, wherein a first end of the telescope-retainer is pivotably supported on the first tensioning arm and a second end of the telescope-retainer is pivotably supported on the second tensioning arm.

11. The tensioning device according to claim 10 ,
wherein the telescope-retainer comprises a first part and a second part, which are telescopic relative to each other; and
wherein a first end of the second spring is axially supported against the first part of the telescope-retainer and a second end of the second spring is axially supportable against the second part of the telescope-retainer.

12. The tensioning device according to claim 1 ,
wherein at least the first spring has a first support portion, which is supported on the first tensioning arm, and a second support portion, which is at least supportable on the second tensioning arm, as well as a curved spring portion extending between the first support portion and the second support portion.

13. The tensioning device according to claim 1 , wherein at least the first spring is formed as a bow spring having a circumferential extension of less than 360° around a pivot axis of the tensioning arms.

14. The tensioning device according to claim 1 , wherein the base member has an opening formed such that at least one of a drive shaft and drive belt pulley of an accessory can extend into the opening in a contact-free manner.

15. The tensioning device according to claim 1 ,
wherein the tensioning rollers form a tensioning roller center plane perpendicular to roller axes of the tensioning rollers, and a bearing of the tensioning arms forms a bearing center plane perpendicular to the pivot axis;
wherein the tensioning roller center plane and the attachment attaching the base member are arranged on different sides of the bearing center plane.

Assignees

• Muhr & Bender Kg

Inventors

• Pfeifer Simon
• Stephan Fabian

Classifications

• F16H2007/0874

  Two or more finally actuated members · CPC title

• F16H2007/0865

  Pulleys · CPC title

• F16H2007/081

  Torsion springs · CPC title

• F16H7/1281 Primary

  where the axis of the pulley moves along a substantially circular path · CPC title

• F16H7/1218 Primary

  of the dry friction type · CPC title