Belt tensioner and method for installing a belt tensioner

Patent metadata

Field	Value
Publication number	US-10059303-B2
Application number	US-201515304875-A
Country	US
Kind code	B2
Filing date	Apr 30, 2015
Priority date	May 6, 2014
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

In a belt tensioner ( 10 ) for a seat belt comprising an elongate pressure reservoir ( 12 ), a piston ( 18 ) movably supported in the pressure reservoir ( 12 ) in the longitudinal direction to which piston pressurized fluid can be applied and which in this way can be moved in a tensioning direction (S), a mechanical thrust means ( 20 ) interacting with the piston, the thrust means interacting with a gearwheel ( 22 ) and driving the same in the case of restraint, and comprising a stop ( 24 ) on which the piston ( 18 ) abuts in the tensioning direction in a final position, it is provided that between the piston ( 18 ) and the thrust means ( 20 ) a spacer ( 30 ) in the form of a separate member is provided which is dimensioned such that in the final position of the piston ( 18 ) the thrust means ( 20 ) is urged past the stop ( 24 ) by said spacer. Furthermore there is provided a method of mounting a belt tensioner of this type.

First claim

The invention claimed is:

1. A belt tensioner ( 10 ) for a seat belt, comprising an elongate, cylindrical pressure reservoir ( 12 ), a piston movably supported in the longitudinal direction in the pressure reservoir ( 12 ) to which piston pressurized fluid is applied and which thus can be moved in a tensioning direction (S), a mechanical thrust means ( 20 ) interacting with the piston ( 18 ) which thrust means in the case of restraint interacts with a gearwheel ( 22 ) and drives the gearwheel ( 22 ) and a longitudinal extension of the thrust means ( 20 ) is larger than a distance of two teeth of the gearwheel, and comprising a stop ( 24 ) provided on the inside of the pressure reservoir ( 12 ) on which the piston ( 18 ) abuts in the tensioning direction (S) in a final position after activation of the belt tensioner ( 10 ) in which position the piston ( 18 ) seals the pressure reservoir ( 12 ), wherein between the piston ( 18 ) and the thrust means ( 20 ) a spacer ( 30 ) in the form of a separate member is provided which is dimensioned so that in the final position of the piston ( 18 ) the thrust means ( 20 ) is urged past the stop ( 24 ) out of the pressure reservoir, by the spacer.

2. The belt tensioner according to claim 1 , wherein the length of the spacer ( 30 ) is equal to or larger than the length of the stop ( 24 ) in the longitudinal direction of the pressure reservoir ( 12 ).

3. The belt tensioner according to claim 1 , wherein the length of the spacer ( 30 ) is dimensioned so that in the final position of the piston ( 18 ) the thrust means ( 20 ) is completely forced out of the pressure reservoir ( 12 ).

4. The belt tensioner according to claim 1 , wherein the spacer ( 30 ) and the piston ( 18 ) are in positive engagement.

5. The belt tensioner according to claim 1 , wherein a projection engaging in a recess on the piston side or on the spacer side or vice versa is provided on the spacer ( 30 ) and/or on the piston ( 18 ).

6. A belt tensioner ( 10 ) for a seat belt, according to claim 1 , comprising an elongate, cylindrical pressure reservoir ( 12 ), a piston ( 18 ) movably supported in the pressure reservoir ( 12 ) in the longitudinal direction to which piston pressurized fluid may be applied and which in this way can be moved in a tensioning direction (S), a mechanical thrust means ( 20 ) interacting with the piston ( 18 ) which thrust means in the case of restraint interacts with a gearwheel ( 22 ) and drives the gearwheel ( 22 ) and a longitudinal extension of the thrust means ( 20 ) is larger than a distance of two teeth of the gearwheel ( 22 ), and comprising a stop ( 24 ) provided on the inside of the pressure reservoir ( 12 ) on which stop the piston ( 18 ) abuts in the tensioning direction (S) in a final position in which the piston ( 18 ) seals the pressure reservoir ( 12 ), wherein in an initial position of the piston ( 18 ) prior to activation of the belt tensioner ( 20 ) the stop ( 24 ) fixes jams, the thrust means ( 20 ) within the pressure reservoir ( 12 ).

7. The belt tensioner according to claim 6 , wherein the stop ( 24 ) is formed by an embossing of the pressure reservoir ( 12 ) by which the cross-section of the pressure reservoir ( 12 ) is narrowed so that the thrust means ( 20 ) is jammed within the pressure reservoir ( 12 ).

8. A method of mounting a belt tensioner ( 10 ) according to claim 6 , characterized by the following steps of:
a) inserting the thrust means ( 20 ) into the pressure reservoir ( 12 ), and
b) subsequently introducing the stop ( 24 ) to the pressure reservoir ( 12 ), wherein the thrust means ( 20 ) is fixed in the pressure reservoir ( 12 ) by the stop ( 24 ).

9. The method according to claim 8 , wherein the stop ( 24 ) is produced by embossing.

10. A belt tensioner for a seat belt, comprising:
a pressure reservoir extending in a longitudinal, tensioning direction and including a stop;
a piston positioned within the pressure reservoir for movement in the tensioning direction;
a mechanical thrust means movable by the piston within the pressure reservoir for driving a gearwheel coupled to the seat belt, the thrust means extending in the tensioning direction a distance greater than a distance of two teeth of the gearwheel; and
a spacer separate from the piston and positioned between the piston and the thrust means, the spacer being dimensioned such that, upon activation of the belt tensioner to apply pressurized fluid to the piston, the piston urges the thrust means past the stop and has a final position abutting the stop to seal the pressure reservoir.

11. The belt tensioner according to claim 10 , wherein the spacer has a final position, following activation of the belt tensioner, jammed at the stop.

12. The belt tensioner according to claim 10 , wherein the final position of the piston is upstream of the stop.

13. The belt tensioner according to claim 10 , wherein the spacer includes one of a projection and a recess and the piston includes the other of the projection and the recess for interconnecting the spacer and the piston.

14. The belt tensioner according to claim 10 , wherein the spacer has a length in the tensioning direction equal to or greater than a length of the stop in the tensioning direction.

15. The belt tensioner according to claim 10 , wherein the stop is U-shaped.

16. The belt tensioner according to claim 10 , wherein the spacer is dimensioned so that in the final position of the piston the thrust means is urged out of the pressure reservoir by the spacer.

17. A method of mounting a belt tensioner according to claim 10 , comprising the following steps of:
a) inserting the thrust means into the pressure reservoir; and
b) subsequently forming the stop on the pressure reservoir such that the stop holds the thrust means in position in the pressure reservoir.

18. The method according to claim 16 , wherein the stop is produced by embossing.

Assignees

• Trw Automotive Gmbh

Inventors

• Moedinger Thomas
• Nuding Martin
• Pregitzer Andreas
• Gentner Bernd

Classifications

• B60R22/4633 Primary

  Linear actuators, e.g. comprising a piston moving along reel axis and rotating along its own axis · CPC title

• B60R2022/468

  characterised by clutching means between actuator and belt reel · CPC title

• B60R2022/4642

  the gas directly propelling a flexible driving means, e.g. a plurality of successive masses, in a tubular chamber · CPC title