WO1994004798B1

WO1994004798B1 - Gripper tool for engine valve disassembly/assembly

Info

Publication number: WO1994004798B1
Application number: PCT/US1993/007854
Authority: WO
Filing date: 1993-08-20
Publication date: 1994-03-31

Abstract

The method of facilitating assembly and disassembly of valves in a cylinder head uses a gripping tool (1) which has a base consisting of a flat ring (2) onto which are mounted three posts (4, 6, 8) extending upwardly therefrom. Rotatable and slidable clips (14, 16) with magnets (15, 17) are mounted on at least two of the posts (4, 6) to capture the loose key bolts (26). A plate (10) is attached to the top of the posts and a clip (18) may extend upwardly therefrom to permit attachment of an adapter for use with a drill press. The flat ring (2) is centered over the top of the valve stem (22) and key bolt (26) and rests on top of the upper cup (25) which presses against the top of the ring which retains the spring (24). Force applied to the top of the tool presses down on the upper cup, compressing the spring to release the key bolt (26). For re-assembly, a centering ring (70) holds the spring centered with the cam bucket bore, providing the contact surface for the flat ring (2). To facilitate transfer of the cylinder head between work stations, an elastic sheet (78) with an opening for each valve stem locks the valves in place before assembly has been completed.

Claims

AMENDED CLAIMS[received by the International Bureau on 28 February 1994 (28.02.94); original claims 1-4 amended; new claims 5-8 added; original claims 5-11 replaced by amended claims 9-15 (4 pages)]

1. A device to facilitate removal/replacement of a key bolt from a valve stem for disassembly/assembly of a valve in an engine cylinder head, said device comprising: a base ring having an outer diameter and an inner diameter, an upper surface and a lower surface, said outer diameter being substantially the same as a diameter of a retaining ring which retains a spring on said valve stem and said inner diameter being larger than an outer diameter of said key bolt; a plurality of posts mounted on said upper surface and extending upwardly therefrom; and a top plate attached to said plurality of posts in a parallel relationship with said base ring; wherein said lower surface is disposed on top of said retaining ring with said valve stem generally centered within said base ring and a pressure means applies pressure to said top plate so that said base ring presses against said retaining ring.

2. A device as in Claim 1 wherein said pressure means comprises an inertia hammer.

3. A device as in Claim 1 wherein said pressure means comprises a drill press.

4. A device as in Claim 1 further comprising: a plurality of magnetic clips slidably and rotatably disposed on at least two of said plurality of posts.

5. A device as in Claim 1 further comprising an adapter disposed on said top plate to facilitate attachment of said pressure means.

6. A device as in Claim 1 wherein said base ring is flat.

7. A device as in Claim 1 wherein said plurality of posts comprises three posts.

8. A device as in Claim 1 wherein each of said plurality of posts has a length greater than a protruding length of said valve stem above said retaining ring when a valve spring below said retaining ring is compressed.

9. In a cylinder head assembly having at least one valve with a valve stem, a spring disposed around said stem, a retaining ring on top of said spring, and a key bolt for locking said retaining ring at a fixed location of said valve stem so that said valve spring is at least partially compressed, a method for facilitating assembly of said key bolt with said valve stem which comprises: inserting a centering ring over said spring within a bore in said cylinder head, said centering ring having a flattened upper end; centering a flat ring over said valve stem on top of said flattened upper end and adjacent said retaining ring; extending a plurality of posts from said flat ring, each of said plurality of posts having a length greater than a protruding length of said valve stem when said spring is compressed; applying a force to a top plate connected to said plurality of posts, said top plate being parallel to and at a fixed distance from said flat ring; compressing said valve spring with said force; releasing and placing said key bolt on said retaining ring at its center adjacent said valve stem; and releasing said force so that said key bolt is wedged between said retaining ring and said valve stem.

10. A method as in Claim 9 further comprising the step of disposing a plurality of magnetic clips on said plurality of posts wherein said magnetic clips slide vertically along said posts and rotate horizontally around said posts to adjust a distance between said key bolt and said predetermined location on said valve stem.

11. A method as in Claim 9 wherein the step of centering a flat ring includes inserting said flat ring into an annular recess in said flattened upper end of said centering ring.

12. A method of assembling a plurality of valve and spring combinations in a cylinder head which comprises : inserting a valve stem of each valve into a corresponding valve guide in said cylinder head; providing an elastic sheet having a plurality of openings therein, each opening corresponding to the location of each said valve stem; stretching said elastic sheet and inserting an end of each valve stem through its corresponding opening in said elastic sheet; releasing said elastic sheet so that its resiles to lock each said valve stem in place; transporting said cylinder head to a work table where said valve and spring combinations are to be assembled; clamping said cylinder head to said work table; removing said elastic sheet; sliding a spring over each said valve stem; sliding a retaining ring on top of said spring; centering a flat ring over said valve stem on top of said retaining ring; disposing a plurality of magnetic clips on a plurality of posts connected to said flat ring; applying a force to a top plate connected to said plurality of posts, said top plate being parallel to end at a fixed distance from said flat ring; compressing said valve spring with said force; placing a key bolt on said plurality of magnetic clips; sliding said magnetic clips to be magnetically close to said retaining ring; releasing and placing said key bolt on said retaining ring at its center adjacent said valve stem; and releasing said force so that said key bolt is wedged between said retaining ring and said valve stem.

13. A method as in Claim 10 wherein the step of providing an elastic sheet including selecting a rubber or rubber¬ like material.

14. A method as in Claim 10 wherein the step of transporting said- cylinder head to a work table includes placing said cylinder head on a table having an inflatable bladder for lifting said valve to facilitate access to said valve stem.

15. A method as in Claim 10 wherein the step of centering a flat ring comprises: inserting a centering ring over said spring within a bore in said cylinder head, said centering ring having a flattened upper end; and inserting said flat ring into an annular recess in said flattened upper end of said centering ring.