LOCK WASHER

• US 3,680,619 A
• Filed: 09/04/1970
• Issued: 08/01/1972
• Est. Priority Date: 06/03/1968
• Status: Expired due to Term

• Current Assignee: Harold R. Sparks
• Original Assignee: Harold R. Sparks
• Inventors: Sparks, Harold R.
• Primary Examiner(s): Britts, Ramon S.
• Application Number:
  US05/069,874
• Time in Patent Office: 697 Days
• Field of Search: 151/36,37,34,35,38 85/50,51 10/73,155A,155R
• US Class Current: 411/134
• CPC Class Codes: F16B 39/24 by means of washers, spring washers, or resilient plates that lock against the object locking to the screw-thread F16B39/14 , F16B39/34, F16B39/36
• CPC Class Codes: Y10S 411/958 Coiled washer
• CPC Class Codes: Y10S 411/959 Bolt- or nut-carried

Abstract

A lock washer comprising a length of wire of substantially trapezoidal or parallelogram cross section formed into a helical configuration, the lock washer having a radially directed slit at a predetermined angle to the axis thereof, whereby the ends of the lock washer define inclined abuttingly engageable surfaces, the lock washer having radially spaced inner and outer surfaces inclined relative to the axis thereof, and axially spaced upper and lower surface portions inclined radially inwardly and upwardly toward the axis thereof, whereby the lock washer originally assumes a helical configuration but upon tightening of an associated bolt, stud, nut, or the like, the helix of the lock washer is removed and the lock washer assumes a generally conical configuration and is thereby adapted to exhibit the superior tightening characteristics of a conical lock washer.

Claims

1. A lock washer comprising a length of wire formed into a helical configuration, said lock washer being formed with a generally radially directed slit at a predetermined angle to the axis of said lock washer, whereby the end portions of said lock washer define inclined abuttingly engageable surfaces which are axially offset when said lock washer is in a substantially unstressed condition, said lock washer having radially spaced inner and outer surface portions inclined radially outwardly and upwardly relative to the axis of said lock washer, and axially spaced upper and lower surface portions joining the axial extremities of said inner and outer surfaces, said upper and lower surface portions being inclined radially inwardly and upwardly when said lock washer is in a substantially unstressed and partially stressed condition, whereby said lock washer assumes a generally conical configuration when said end portions thereof are biased into substantial axial alignment with said inclined surfaces abuttingly engaged, said abuttingly engaged inclined surface causing said end portions to cooperatively rotate upon further stressing to bias said lower surface portion to a position substantially perpendicular to the axis of said lock washer when the same is in a substantially stressed condition.

2. A lock washer as defined in claim 1 wherein said radially spaced inner and outer surface portions are parallel and said upper and lower surface portions are parallel, whereby said lock washer is generally parallelogram-shaped in transverse section.

3. A lock washer as defined in claim 2 wherein said radially spaced inner and outer surface portions are arranged substantially perpendicular to said upper and lower surface portions, whereby said lock washer is substantially rectangular shaped in transverse section.

4. A lock washer as defined in claim 1 wherein said radially spaced inner and outer surface portions are substantially parallel and said upper and lower surface portions are substantially non-parallel, whereby said lock washer is substantially trapezoidal-shaped in transverse section.

5. A lock washer as defined in claim 1 wherein said upper and lower surface portions are inclined radially inwardly and upwardly toward the axis of said lock washer, with the angle of said upper surface portion being greater than that of said lower surface portion, saId upper and lower surface portions each forming acute angles with said inner surface portion and obtuse angles with said outer surface portion.

6. In combination in an assembly for fastening first and second members together, means on said first member defining a threaded aperture, means on said second member defining an enlarged head portion and a shank portion adapted to be threadably received within said aperture, a lock washer interposed between said head portion and said means defining said aperture for limiting relative movement between said members, said lock washer being formed with a generally radially directed slit at a predetermined angle to the axis of said lock washer, whereby the end portions of said lock washer define inclined surfaces which are axially offset when said lock washer is in a substantially unstressed condition, said lock washer further having radially spaced inner and outer surface portions and upper and lower surface portions and assuming a generally helical configuration in an unstressed condition, said upper and lower surface portions being inclined radially inwardly and upwardly and said inner and outer surface portions being inclined radially outwardly and upwardly whereby said lock washer assumes a generally conical configuration when said end portions thereof are biased into substantial axial alignment, and means on one of said members engageable with one of said surface portions of said lock washer for limiting radially outward expansion thereof as said head portion of said second member is moved toward said first member.

7. An assembly as defined in claim 6 wherein said means on one of said members for limiting radially outward expansion of said lock washer comprises a counterbore on said first member arranged coaxially of said aperture and adapted to engage said outer surface portion of said lock washer as said head portion of said second member is moved toward said first member.

8. An assembly as defined in claim 7 wherein said radially spaced inner and outer surface portions are arranged substantially perpendicular to said upper and lower surface portions, whereby said lock washer is substantially rectangular-shaped in transverse section.

9. An assembly as defined in claim 6 wherein said means for limiting radially outward expansion of said lock washer comprises a radially outwardly and downwardly inclined surface portion formed on the lower side of said head portion and adapted to contiguously engage said upper surface portion of said lock washer as said head portion of said second member is moved toward said first member.

10. An assembly as defined in claim 6 wherein the underside of said head portion defines a radially outwardly and downwardly inclined surface portion, wherein said upper surface portion of said lock washer extends at a relatively acute angle to said inclined surface portion on said head portion when said lock washer is in an unstressed condition, wherein said inner and outer surface portions assume a substantially cylindrical configuration parallel to said lock washer axis, and said upper surface portion assumes an angle complementary to that of said inclined surface portion on said head portion when said lock washer is in a stressed condition, said upper surface portion and said inclined surface portion on said head portion cooperating to prevent said lock washer from deforming radially outwardly when said second member is moved toward said first member.

11. An assembly as defined in claim 6 wherein said second member comprises a bolt having an elongated cylindrical shank section terminating at one end in an enlarged head section, the underside of said head section defining a radially outwardly and downwardly inclined surface portion, and wherein said upper surface portion of said lock washer and said underside of said head section are complementary in shape and contiguously engageable to prevent said lock washer from deforming radially outwardly when saId head section of said bolt is moved axially toward said first member.

12. An assembly as defined in claim 6 wherein said head portion of said second member comprises a nut adapted to be threadably secured on said shank portion of said second member, said nut having a lower surface portion inclined radially outwardly and downwardly at substantially the same angle of said upper surface portion of said lock washer when said lock washer is in a substantially stressed condition.

13. An assembly as defined in claim 6 wherein said second member comprises a bolt having an elongated cylindrical shank section terminating at one end in an enlarged head section, the underside of said head section defining a radially outwardly and downwardly inclined surface portion, wherein said upper surface portion of said lock washer extends at a relatively acute angle to said inclined surface portion on said head section when said lock washer is in an unstressed condition, and wherein said inner and outer surface portions assume a substantially cylindrical configuration parallel to said lock washer axis and said upper surface portion assumes an angle complementary to that of said inclined surface portion on said head section when said lock washer is in a stressed condition, said upper surface portion and said inclined surface portion on said head section cooperating to prevent said lock washer from deforming radially outwardly when said head section of said bolt is moved toward said first member.

14. An assembly as defined in claim 6 wherein said head portion of said second member comprises a nut adapted to be threadably secured to said shank portion of said second member, said nut having a lower surface portion inclined radially outwardly and downwardly, wherein said upper surface portion of said lock washer extends at a relatively acute angle to said inclined surface portion on said nut when said lock washer is in an unstressed condition, and wherein said inner and outer surface portions assume a substantially cylindrical configuration parallel to said lock washer axis and said upper surface portion assumes an angle complementary to that of said inclined surface portion on said nut when said lock washer is in a stressed condition, said upper surface portion and said inclined surface portion on said nut cooperating to prevent said lock washer from deforming radially outwardly when said nut is moved toward said first member.

15. An assembly as defined in claim 6 wherein said second member comprises a bolt having an elongated shank section terminating at one end in an enlarged head section, and wherein the inner diameter of said lock washer is slightly smaller than the diameter of said shank section whereby said lock washer is clampingly engaged with the outer periphery of said shank section when said lock washer is in an unstressed condition, with the inner diameter of said lock washer being slightly greater than the diameter of said shank section when said lock washer is in a stressed condition.

16. An assembly as defined in claim 6 wherein said shank portion of said second member comprises a stud member and wherein said head portion of said second member comprises a nut adapted to be threadably received on said stud member, the underside of said nut being formed with an axially extending cylindrical surface portion and with a radially inwardly and upwardly inclined surface portion, said surface portions of said nut defining an annular recess around the underside thereof, and wherein the inner diameter of said lock washer is slightly greater than the diameter of said cylindrical surface portion, said upper surface portion of said lock washer being complementary to said radially inwardly and upwardly inclined surface portion of said nut, and which includes a radially outwardly flared portion on the lower end of said nut for maintaining said lock washer in a partially stressed condition wherein said end portions thereof are substantially axially aligned.

17. An assembly as Defined in claim 6 wherein the underside of said head portion is formed with a radially extending surface portion defining an axially upwardly extending annular recess at the radially innermost portion thereof, and wherein said upper surface portion of said lock washer is provided with an axially extending annular shoulder portion complementary to and engageable with said recess in said head portion for preventing said lock washer from deforming radially outwardly when said head portion is moved axially toward said first member.

18. A lock washer comprising a length of wire formed into a helical configuration, said lock washer being formed with a generally radially directed slit at a predetermined angle away from the axis of said lock washer, whereby the end portions of said lock washer define inclined surfaces which are axially offset when said lock washer is in a substantially unstressed condition, said lock washer having radially spaced inner and outer surface portions inclined radially outwardly and upwardly relative to the axis of said lock washer, and axially spaced upper and lower surface portions joining the axial extremities of said inner and outer surfaces, said upper and lower surface portions being inclined radially inwardly and upwardly when said lock washer is in a substantially unstressed and partially stressed condition, whereby said lock washer assumes a generally conical configuration when said end portions thereof are biased into substantial axial alignment, adjacent ones of said surface portions forming two acute angles and two obtuse angles.

19. A lock washer as defined in claim 18 wherein said radially spaced inner and outer surface portions are parallel and said upper and lower surface portions are parallel, whereby said lock washer is generally parallelogram-shaped in transverse section.

20. A lock washer as defined in claim 18 wherein said radially spaced inner and outer surface portions are substantially parallel and said upper and lower surface portions are substantially non-parallel, whereby said lock washer is substantially trapezoidal-shaped in transverse section.

21. A lock washer as defined in claim 18 wherein said upper and lower surface portions are inclined radially inwardly and upwardly toward the axis of said lock washer, with the angle of said upper surface portion being greater than that of said lower surface portion, said upper and lower surface portions each forming acute angles with said inner surface portion and obtuse angles with said outer surface portion.

22. In combination in an assembly for fastening first and second members together wherein said first member has means defining a threaded aperture, means on said second member defining an enlarged head portion and a shank portion adapted to be threadably received within said threaded aperture of said first member, a lock washer carried on said shank portion for interposition between said head portion and said means defining said aperture for limiting relative movement between said members, said lock washer being formed with a radially directed slit at a predetermined angle to axis of said lock washer, whereby the end portions of said lock washer define inclined surfaces which are axially offset when said lock washer is in a substantially unstressed condition, said lock washer further having radially spaced inner and outer surface portions and upper and lower surface portions and assuming a generally helical configuration in an unstressed condition with said lock washer resiliently engaging said shank to retain said lock washer portion on said shank portion when said lock washer is unstressed, said radially spaced inner and outer surface portions being arranged substantially perpendicular to said upper and lower surface portions, whereby said lock washer is substantially rectangular-shaped in transverse section, said upper and lower surface portions being inclined radially inwardly and upwardly whereby said lock washer assumes a generally coNical configuration when said end portions thereof are biased into substantial axial alignment, and said lock washer being disengaged from said shank portion by radially outward expansion thereof upon predetermined stressing of said lock washer to allow relative rotation between said second member and said lock washer.

23. An assembly as defined in claim 22 further including means on one of said members engageable with one of said surface portions of said lock washer for limiting radially outwardly expansion thereof of said head portion of said member for movement toward said first member.

24. An assembly as defined in claim 22 wherein said radially spaced inner and outer surface portions are parallel and said upper and lower surface portions are parallel, whereby said lock washer is generally parallelogram-shaped in transverse section.

25. An assembly as defined in claim 22 wherein said radially spaced inner and outer surface portions are substantially parallel and said upper and lower surface portions are substantially non-parallel, whereby said lock washer is substantially trapezoidal-shaped in transverse section.

26. An assembly as defined in claim 22 wherein said upper and lower surface portions are inclined radially inwardly and upwardly toward the axis of said lock washer, with the angle of said upper surface portion being greater than that of said lower surface portion, said upper and lower surface portions each forming acute angles with said inner surface portion and obtuse angles with said outer surface portion.