Adjustable shock absorber

• US 6,974,002 B2
• Filed: 03/20/2003
• Issued: 12/13/2005
• Est. Priority Date: 03/20/2003
• Status: Active Grant

• Current Assignee: ACE Controls Inc. (Stabilus S.A.)
• Original Assignee: ACE Controls Inc. (Stabilus S.A.)
• Inventors: Heideman, Robert
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US10/393,168
• Publication Number:
  US 20040182662A1
• Time in Patent Office: 999 Days
• Field of Search: 188/285, 188/287, 188/286, 188/322.22, 188/322.15, 16/51, 16/52, 16/82, 267/221, 267/226, 213/223
• US Class Current: 188/285
• CPC Class Codes: F16F 9/346 Throttling passages in the form of slots arranged in cylinder walls
• CPC Class Codes: F16F 9/466 Throttling control, i.e. regulation of flow passage geometry F16F9/464, F16F9/465 take precedence
• CPC Class Codes: F16F 9/48 Arrangements for providing different damping effects at different parts of the stroke F16F9/346, F16F9/516 , F16F9/53 take precedence

Abstract

An adjustable shock absorber for applying a force to a moving member so as to decelerate the member. The present invention provides a cylindrical outer tube having a plurality of circular, angular grooves formed in the inner surface of the tube. A cylindrical inner tube is rotatably disposed within the outer tube. A piston is slidably disposed within the inner tube and is engageable with the moving member. The piston moves between a compressed position and an extended position. The inner tube has a plurality of apertures extending therethrough and fluidly communicatable with the grooves in the outer tube. A screw thread is formed in the outer surface of the inner tube and is fluidly communicatable with the grooves in the outer tube. The inner tube and the outer tube rotate with respect to each other to adjust the level of fluid communication between the rearward end and the forward end of the shock absorber to adjust the level of force applied to the moving member. The use of the screw thread on the inner tube increases the efficiency of the manufacturing process as opposed to conventional processes.

Claims

1. An adjustable shock absorber for applying a force to a moving member so as to decelerate the member comprising:

an outer tube having a substantially cylindrical configuration and a plurality of substantially circular, angular grooves formed in an inner surface of said outer tube;

an inner, substantially cylindrical tube rotatably disposed within said outer tube, and said inner tube having a closed rearward end and an open forward end;

a piston rod having a rearward end slidably disposed within said inner tube and a forward end extending outward from said forward end of said inner tube and engageable with said member, and said piston rod movable between a compressed position, wherein said piston rod is furthest toward said rearward end of said inner tube, and an extended position, wherein said piston rod is furthest toward said forward end of said inner tube;

said inner tube having a plurality of apertures extending therethrough and fluidly communicatable with said grooves in said outer tube;

a screw thread formed in an outer surface of said inner tube, and said screw thread fluidly communicatable with said grooves in said outer tube; and

said inner tube and said outer tube rotatable with respect to each other to adjust the level of fluid communication between a rearward end and a forward end of said shock absorber by adjusting the flow of fluid between said apertures of said inner tube and said grooves of said outer tube and between said grooves of said outer tube and said screw thread of said inner tube to adjust the force applied to said moving member.

2. The adjustable shock absorber stated in claim 1, further comprising:

said piston rod having a rearward end slidably disposed within said inner tube and a forward end extending outward from said forward end of said shock absorber; and

a piston head circumscribing said rearward end of said piston rod wherein a gap exists between said piston rod and said piston head, and said piston head movable between said compressed position, wherein fluid flow is prohibited from passing between said piston head and said piston rod, and said extended position, wherein said fluid flow is open between said piston head and said piston rod.

3. The adjustable shock absorber stated in claim 2, further comprising:

a piston head retainer connected to said rearward end of said piston rod and having at least one aperture extending therethrough;

a shoulder formed on said piston rod, and said piston head captured by said piston head retainer and said shoulder on said piston rod;

said piston head abutting said shoulder in said compressed position to prohibit fluid flow between said piston head and said piston rod and abutting said piston head retainer in said extended position to allow fluid flow between said piston head and said piston rod and through said aperture in said piston head retainer.

4. The adjustable shock absorber stated in claim 1, further comprising:

said screw thread having a male portion and a female portion; and

said apertures and said inner tube located on said male portion of said screw thread on said outer diameter of said inner tube.

5. The adjustable shock absorber stated in claim 4, further comprising:

said male portion of said screw thread slidingly engaging said inner diameter of said outer tube.

6. The adjustable shock absorber stated in claim 1, further comprising:

a passageway in said forward end of said inner tube and in communication with said screw thread for further communicating fluid flow between said rearward end and said forward end of said shock absorber.

7. The adjustable shock absorber stated in claim 1, further comprising:

the force applied to said moving member being adjustable between a maximum force and a minimum force in response to 180°

of relative rotation between said outer tube and said inner tube.

8. The adjustable shock absorber stated in claim 1, further comprising:

said through apertures in said inner tube corresponding in number to said grooves in said outer tube.

9. An improved shock absorber having an inner tube having a rearward end and a forward end wherein said inner tube is closed at the rearward end and open at the forward end, a piston rod slidably received in the inner tube and projecting out of the open forward end of the inner tube for impact by a moving object, an outer tube surrounding the inner tube, a cushioning fluid substantially filling the shock absorber, an adjustable fluid flow path for directing said cushioning fluid between a rearward end and a forward end of said shock absorber, wherein the size of said fluid flow path may be adjusted to selectively vary the impact resistance generated by the movement of said cushioning fluid to said fluid flow path in response to impacting movement of the piston rod toward the closed rearward end of the inner tube, the improvement comprising:

a plurality of apertures extending through said inner tube to communicate said cushioning fluid between an inner portion of said inner tube and said forward end of said shock absorber;

a plurality of substantially circular, angular grooves formed in the inner diameter of said outer tube and communicatable with said apertures;

a screw thread formed on the outside diameter of said inner tube, and said screw thread communicatable with said grooves in said outer tube; and

said inner tube and said outer tube rotatable with respect to one another to adjust the level of communication between said apertures of said inner tube and said grooves of said outer tube and between said grooves of said outer tube and said screw thread in said inner tube to adjust the level of flow of said cushioning fluid between said rearward end and said forward end of said shock absorber in response to said impacting movement of said piston.

10. The improved shock absorber stated in claim 9, further comprising:

said screw thread having a male portion and a female portion; and

said apertures in said inner tube located on said male portion of said screw thread on said outer diameter of said inner tube.

11. The improved shock absorber stated in claim 10, further comprising:

said male portion of said screw thread slidingly engaging said inner diameter of said outer tube.

12. The improved shock absorber stated in claim 9, further comprising:

a passageway in said forward end of said inner tube and in communication with said screw thread for further communicating said cushioning fluid between the rearward end and the forward end of said shock absorber.

13. The improved shock absorber stated in claim 9, further comprising:

said piston rod having a rearward end slidably disposed within said inner tube and a forward end extending outward from said forward end of said shock absorber; and

a piston head slidably coupled to said rearward end of said piston rod for movement between a compressed position, wherein said piston rod slides toward the rearward end of said shock absorber thereby directing said cushioning fluid toward a rearward end of said piston head toward said apertures in said inner tube, and an extended position, wherein said piston rod slides toward the forward end of said shock absorber thereby directing said cushioning fluid to flow from said forward end to said rearward end of said shock absorber between said piston head and said piston rod.

14. The improved shock absorber stated in claim 9, further comprising:

said level of force applied to said moving member is adjustable between a maximum force and a minimum force in response to 180°

of relative rotation between said outer tube and said inner tube.

15. The improved adjustable shock absorber stated in claim 9, further comprising:

said through apertures in said inner tube corresponding in number to said grooves in said outer tube.

16. An adjustable shock absorber, comprising:

an outer, substantially cylindrical tube having a rearward end and a forward end;

an inner, substantially cylindrical tube rotatably disposed within said rearward end of said outer tube;

a piston rod having a rearward end slidably disposed within said inner tube and a forward end slidably disposed within said forward end of said outer tube wherein said forward end of said piston rod is engageable with a moving member;

an outer periphery of said inner tube and an inner periphery of said outer tube having complementary engaging surfaces that combine to provide a passageway between said outer tube and said inner tube for allowing fluid to flow axially along said passageway between said rearward end and said forward end of said outer tube;

said inner tube having a plurality of apertures extending therethrough and communicatable with said passageway wherein all of said apertures are equally spaced axially along said inner tube wherein said fluid flows axially forward of said apertures through said passageway; and

said inner tube and said outer tube rotatable with respect to one another to adjust the level of fluid communication between said rearward end and said forward end of said outer tube by adjusting the flow of fluid between said apertures of said inner tube and said passageway for adjusting the level of force applied to said moving member.

17. The adjustable shock absorber stated in claim 16, further comprising:

at least one of said inner periphery of said outer tube and said outer periphery of said inner tube having at least one recess formed therein.

18. The adjustable shock absorber stated in claim 17, wherein said at least one recess further comprises:

at least one substantially circular groove formed therein.

19. The adjustable shock absorber stated in claim 17, wherein said at least one recess further comprises:

a screw thread formed therein.

20. The adjustable shock absorber stated in claim 16, further comprising:

a fluid storage compartment disposed within said forward end of said outer tube and in fluid communication with said passageway.

21. An adjustable shock absorber for applying a force to a moving member, comprising:

an outer tube having an inner surface with at least one first recess formed therein;

an inner tube rotatably disposed within said outer tube and having at least one second recess formed in an outer surface of said inner tube, wherein said at least one second recess is substantially helical, and said inner tube having at least one aperture;

said outer tube receiving said inner tube and said first recess of said outer tube complementarily engaging said second recess of said inner tube to define a passageway for allowing fluid to flow axially along said passageway between said outer tube and said inner tube forward of said at least one aperture;

a piston rod having a rearward end slidably disposed inside said inner tube and a forward end disposed outside said outer tube;

said at least one aperture and said at least one first and second recess cooperate to define at least one fluid flow opening; and

said inner tube is rotatable with respect to said outer tube to vary the size of said at least one fluid flow opening.

22. The adjustable shock absorber of claim 21 wherein said at least one second recess is a screw thread.

23. The adjustable shock absorber of claim 21 wherein said shock absorber further comprises:

said piston rod engageable with a moving member to apply a force to said moving member wherein said force has a maximum value when said size of said at least one fluid flow opening has a minimum value and said force has a minimum value when said size of said at least one fluid flow opening has a maximum value.