CLAMP ASSEMBLY FOR A STEERING COLUMN ASSEMBLY

• US 20100275721A1
• Filed: 10/10/2008
• Published: 11/04/2010
• Est. Priority Date: 10/12/2007
• Status: Active Grant

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Havlicek, Jan, Davies, Niclas
• Granted Patent: US 8,413,541 B2
• Time in Patent Office: Days
• US Class Current: 74/493
• CPC Class Codes: B62D 1/184 Mechanisms for locking columns at selected positions
• CPC Class Codes: Y10T 24/44017 with specific mounting means for attaching to rigid or semirigid supporting structure or structure-to-be-secured

Abstract

A clamp assembly secures a fixed portion of a steering column assembly to a movable portion of a steering column. It comprises a rack of teeth carried by the moving portion and a rack of teeth carried by the fixed portion and an inner hollow toothed block nested inside an outer hollow toothed block, each carrying at least one rack of teeth with the rack of teeth on the inner block facing the rack of teeth on the moving portion and the rack of teeth on the outer block facing the rack of teeth on the fixed portion. A retaining clip provides a lost motion coupling between the retaining clip and the inner toothed block and an independent lost motion coupling between the retaining clip and the inner toothed block and an independent motion coupling between the retaining clip and the outer toothed block. First, second and third springs bias the teeth of the blocks into and out of engagement with the racks when locked and unlocked. The assembly helps prevent damage to the teeth with the springs permitting the damage force on the blocks to be independently absorbed.

Claims

1. A clamp assembly for securing a fixed portion of a steering column assembly to a moving portion of a steering column comprising:

a rack of teeth carried by said moving portion and a rack of teeth carried by said fixed portion,

a clamp pin which passes through an opening in said fixed portion and an opening in said moving portion,

an inner hollow toothed block and an outer hollow toothed block, each carrying at least one rack of teeth with said rack of teeth on said inner block facing said rack of teeth on said moving portion and said rack of teeth on said outer block facing said rack of teeth on said fixed portion,

said inner toothed block being mounted onto said clamp pin so that it can move to and fro along said pin and said outer toothed block being mounted on said inner toothed block such that said outer block can move to and fro along said inner block;

a clamping means mounted on an end of said clamp pin,

a clamp block mounted on said pin between said clamping means and said inner block and said outer block and which is biased into engagement with said fixed portion by said clamping means when said assembly is locked,

a first spring which acts between said clamping means and said fixed portion to release said clamping means from said fixed portion when said assembly is unlocked;

a retaining clip having a first part fixed relative to said clamp block and a second part, spaced from said first part, which provides a lost motion coupling between said retaining clip and said inner toothed block and an independent lost motion coupling between said retaining clip and said outer toothed block such that said second part engages both said inner block and said outer block when said assembly is unlocked but both inner and outer blocks can independently move away from said second part when said assembly is locked,

a second spring which acts between said clamp block and said inner block to bias said inner block into engagement with said second part of said retaining clip when said assembly is unlocked and also to bias said teeth of said inner block into engagement with said teeth of said moving portion when said assembly is locked, and

a third spring which acts between said clamp block and said outer block to bias said outer block into engagement with said second part of said retaining clip when said assembly is unlocked and also to bias said teeth of said outer block into engagement with said teeth of said fixed portion when said assembly is locked.

2. A clamp assembly according to claim 1 wherein said clip has a first part which is biased towards said clamping block by said first spring and which is mounted on said clamp pin sandwiched between said inner block and said outer block and said clamping block.

3. A clamp assembly according to claim 1 wherein said second part of said retaining clip comprises at least two hooked arms, a first one of said hooked arms engaging said outer block and a second one of said hooked arms engaging said inner block.

4. A clamp assembly according to claim 3 wherein said hooked arms are located within respective grooves provided in said inner block and said outer block.

5. A clamp assembly according to claim 1 wherein said clamping block has a base portion slidingly mounted onto said clamp pin and at least one arm which extends out to react against said fixed rack portion when said assembly is locked.

6. A clamp assembly according to claim 5 wherein said clamping block is at least partially sandwiched between said clamping means and said first spring.

7. A clamp assembly according to claim 1 wherein at least two of the first spring, second spring and third spring are combined as a single element.

8. A clamp assembly according to claim 7 wherein said single element comprises three springs connected by a web which includes an opening through which said clamp pin passes, said three springs comprising compression springs.

9. A clamp assembly according to claim 1 wherein said outer hollow block is supported and guided through its movement by a sliding engagement with said first member.

10. A clamp assembly according to claim 1 wherein said moving rack portion comprises a part of a guide rail secured to a steering column shroud and said fixed portion comprises a guide bracket secured to a vehicle, said moving rack portion being located on an opposite side of said fixed rack portion to said inner block and said outer block.

11. A clamp assembly according to claim 10 wherein said slot in said moving rack portion has a major axis aligned with a direction of movement of said shroud for reach and said slot in said fixed rack portion has a major axis aligned with a direction of movement of said shroud for rake angle.

12. A clamp assembly according to claim 1 wherein said clamp means comprises a fixed stop located on an end of said clamp pin.

13. A clamp assembly according to claim 1 wherein said teeth of said racks on said fixed and moving portions comprise saw teeth.

14. A steering column assembly including an adjustable steering column shroud and a support bracket and a clamp assembly according to claim 1 in which said fixed rack portion is secured to said bracket and said moving rack portion is secured to said shroud.