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US 5,704,748 AGranted
Self-locking machine screw
OwnerRichard Criswellinventor
Life of this patent
Estimating the term…
Abstract
A machine screw has a recess in its body extending from the threaded end into the body. The recess intersects the threads. A tang slot extends across the end of the machine screw body. A locking member is in the recess and the tang of the locking member is in the tang slot. The locking member includes a spring which extends into the thread space so that, when the machine screw is screwed into a threaded part, the spring is deflected by the threaded part to releasably lock the machine screw in place.
Claims26
A self-locking machine screw comprising:
- a male substantially cylindrical body having a radius and having a first end and a second end defining the length of said body, said body having screw threads having a root diameter, said screw threads extending at least a portion of the length of said body from said first end toward said second end;
- a recess in said first end of said body, said recess having walls extending generally lengthwise with respect to the length of said body and intersecting said screw threads so that said recess is radially partially exposed, said recess being more narrow at said root diameter than at a smaller radius, a stop wall;
- a resilient metallic locking member in said recess, said metallic locking member having a plurality of thread engagement surfaces thereon sized and shaped to engage on thread surfaces in a threaded hole, said metallic locking member being positioned in said recess so that at least a portion of said engagement surfaces are exposed out of said recess so that when said machine screw is turned into a threaded hole, a portion of said thread engagement surfaces on said resilient metallic locking member which is exposed from said recess is resiliently deflected to provide a controlled frictional drag of prevailing torque that resists inadvertent turning of the screw;
- and
- said metallic locking member engaging on said stop wall to inhibit rotation of said metallic locking member in said recess.
2 more elements
A self-locking machine screw comprising:
- a male substantially cylindrical screw-threaded body having a first end and a second end with said screw threads extending from said first end toward said second end;
- a substantially cylindrical recess in said first end of said body, said recess having walls intersecting said screw threads so that said recess is partially exposed;
- a coil spring locking member within said recess, a tang on said locking member extending away from said coil portion of said locking member and a tang slot in said body to receive said tang to position and retain said coil spring in said recess so that when said machine screw is turned into a threaded hole, the portion of said locking member which is exposed from said recess is deflected to provide a controlled frictional drag of prevailing torque that resists inadvertent turning of the screw.
A self-locking machine screw comprising:
- a male substantially cylindrical screw-threaded body having a first end and a second end with said screw threads extending from said first end toward said second end;
- a substantially cylindrical recess in said first end of said body, said recess having walls intersecting said screw threads so that said recess is partially exposed;
- a coil spring locking member within said recess, said spring being wound of wire having two surfaces substantially 60 degrees with respect to each other and said surfaces face substantially the same way as said screw threads on said machine screw body so that when said machine screw is turned into a threaded hole, the portion of said locking member which is exposed from said recess is deflected to provide a controlled frictional drag of prevailing torque that resists inadvertent turning of the screw.
A machine screw comprising:
- a body, said body being substantially cylindrical, said body having a first end, said body having a head opposite said first end, said body having screw threads on the exterior surface thereof extending from said first end toward said head;
- a recess in said body open to said first end of said body, said recess having an interior surface which intersects the surfaces of said screw threads, said recess being wider radially inward from the root diameter of said screw threads, a stop wall in said body at said recess;
- a resilient metallic locking member in said recess, said locking member having thread engaging surfaces thereon shaped to engage threads in a part into which said machine screw is threaded, said resilient metallic locking member being resiliently urged in a direction to be exposed at said screw threads so that when said machine screw is screwed into a threaded hole in a part, said locking member is deflected to resist removal of said machine screw from the threaded part, and said resilient metallic locking member engaging said stop wall to inhibit rotation of said locking member when said bolt is threaded into a part.
A machine screw comprising:
- a body, said body being substantially cylindrical, said body having a first end, said body having a head opposite said first end, said body having screw threads on the exterior surface thereof extending from said first end toward said head;
- a substantially cylindrical recess in said body open to said first end of said body, said recess having an interior surface which intersects the surfaces of said screw threads;
- a metallic spring locking member in said recess, said spring being wound of metallic wire which has two surfaces positioned at substantially 60 degrees with respect to each other, said locking member being resiliently urged in a direction to be exposed at said screw threads so that when said machine screw is screwed into a threaded hole in a part, said locking member is deflected to resist removal of said machine screw from the threaded part.
A machine screw comprising:
- a body, said body being substantially cylindrical, said body having a first end, said body having a head opposite said first end, said body having screw threads on the exterior surface thereof extending from said first end toward said head;
- a recess in said body open to said first end of said body, said recess having an interior surface which intersects the surfaces, a stop wall in said body at said recess of said screw threads;
- a metallic spring locking member in said recess, said spring being wound as a series of spaced partial toroidal coils with offsets between the toroidal coils, said locking member having thread engaging surfaces thereon shaped to engage threads in a part into which said machine screw is threaded, said resilient metallic locking member being resiliently urged in a direction to be exposed at said screw threads so that when said machine screw is screwed into a threaded hole in a part, said locking member is deflected to resist removal of said machine screw from the threaded part, and said resilient metallic locking member engaging said stop wall to inhibit rotation of said locking member when said bolt is threaded into a part.
A machine screw comprising:
- a body, said body being substantially cylindrical, said body having a first end, said body having a head opposite said first end, said body having screw threads on the exterior surface thereof extending from said first end toward said head;
- a recess in said body open to said first end of said body, said recess having an interior surface which intersects the surfaces, a stop wall in said body at said recess of said screw threads;
- a spring locking member in said recess, said spring being shorter than the length of said recess so that substantially two threads on said machine screw extend past said spring when said spring is in said recess, said locking member having thread engaging surfaces thereon shaped to engage threads in a part into which said machine screw is threaded, said resilient metallic locking member being resiliently urged in a direction to be exposed at said screw threads so that when said machine screw is screwed into a threaded hole in a part, said locking member is deflected to resist removal of said machine screw from the threaded part, and said resilient metallic locking member engaging said stop wall to inhibit rotation of said locking member when said bolt is threaded into a part.
A machine screw comprising:
- a body, said body being substantially cylindrical, said body having a first end, said body having a head opposite said first end, said body having screw threads on the exterior surface thereof extending from said first end toward said head;
- a recess in said body open to said first end of said body, said recess having an interior surface which intersects the surfaces, a stop wall in said body at said recess of said screw threads;
- a spring locking member in said recess, a tang on said spring and a tang slot at least partway across said machine screw, said tang slot being sized to receive said tang to prevent rotation of said spring, said locking member having thread engaging surfaces thereon shaped to engage threads in a part into which said machine screw is threaded, said resilient metallic locking member being resiliently urged in a direction to be exposed at said screw threads so that when said machine screw is screwed into a threaded hole in a part, said locking member is deflected to resist removal of said machine screw from the threaded part, and said resilient metallic locking member engaging said stop wall to inhibit rotation of said locking member when said bolt is threaded into a part.
A machine screw comprising:
- a body, said body being substantially cylindrical, said body having a first end, said body having a head opposite said first end, said body having screw threads on the exterior surface thereof extending from said first end toward said head;
- two recesses in said body open to said first end of said body, said recesses being substantially diametrically oppositely spaced and each having an interior surface which intersects the surfaces of said screw threads;
- a resilient metallic spring locking member, said locking member having two springs thereon respectively positioned within said two recesses, both of said recesses intersecting said threaded surfaces so that both of said springs are positioned for locking said machine screw in a threaded part in said recess, said locking member so that when said machine screw is screwed into a threaded hole in a part, said locking member is deflected to resist removal of said machine screw from the threaded part.
A machine screw comprising:
- a body, said body being substantially cylindrical, said body having a first end, said body having a head opposite said first end, said body having screw threads on the exterior surface thereof extending from said first end toward said head;
- a recess in said body open to said first end of said body, said recess having an interior surface which intersects the surfaces of said screw threads;
- a locking member in said recess, said locking member being a spring configured to comprise a plurality of connected semi-toroidal turns, so that each turn can provide opposite radial forces at each semi-toroid, said locking member being resiliently urged in a direction to be exposed at said screw threads so that when said machine screw is screwed into a threaded hole in a part, said locking member is deflected to resist removal of said machine screw from the threaded part.
Dependencies are inferred from the claim text.