Self-locking vibration-proof lock washer and cooperating threaded fastener

Claim 2

A lock washer comprising a continuous ring of material substantially harder than the workpiece against which said ring is to be compressed in its assembly environment, said ring being generally rectangular in cross section and of sufficient area to have a hoop tension strength at least as great as the design tension strength of the largest diameter threaded shank usable with said washer, the outer periphery of said washer having wrench-engaging surfaces usable to rotate said washer about the axis thereof, a first end face of said washer having a plurality of low-height sharp-edged teeth extending generally radially thereof with one face of each inclined obtusely and the other face of each inclined acutely to said one washer end face and in a direction such that said teeth are adapted to cam over the face of a workpiece when said washer is rotated in a fastener tightening direction and to cut into the juxtaposed surface of a workpiece when said washer is rotated in a fastener loosening direction, said washer having a punch-formed generally cylindrical central opening substantial portions of which have an axial length along the end thereof remote from said sharp-edged teeth not materially less than half the washer thickness, the rim edge of said cylindrical opening remote from said first end face having a ring of shallow notches formed therein which notches have relatively long generally helical bottom surfaces inclined inwardly and toward said first end face at an obtuse angle to the washer axis, the deep end of said notches having an axial and a radial depth each of which is a minor fraction of the washer thickness and the lateral edges of said helical surfaces converging into substantial merger with one another at the rim edge of said central opening, said notches having a short face lying in a generally radial plane, and said relatively long generally helical surface having a pitch extending generally in the same direction but at least double the pitch of the threads of a threaded fastener with which said washer is to be used.

Claim 3

A lock washer as defined in claim 1 characterized in that the outer periphery of said washer is provided with at least one set of hexagonal wrench engaging faces lying in planes substantially parallel to the washer axis.

Claim 4

A lock washer as defined in claim 1 characterized in that said washer is dish-shaped with said first end face being convex and the other end face being concave.

Claim 5

A lock washer as defined in claim 1 characterized in that said first washer end face is convex, and the outer radial ends of said teeth being spaced inwardly from thE juxtaposed outer periphery of said washer.

Claim 6

A lock washer as defined in claim 1 characterized in that the teeth in said first end face are substantially deeper at one radial end thereof than at the other end thereof.

Claim 7

A lock washer comprising a continuous ring punched from strip metal of uniform thickness and substantially harder than the workpiece against which said ring is to be compressed in the assembly environment thereof, said washer having first and second end faces and a generally cylindrical central opening major portions of which have an axial length measured from one end face thereof not materially less than half the washer thickness and a non-circular wrench-engageable outer periphery, said first end face of said washer being upset to provide a ring of low-height teeth having a sharp edge extending generally radially thereof with one face of each inclined acutely and the other face lying generally in an axial plane whereby said teeth are adapted to cam over the surface of a workpiece when said washer is rotated thereover in a direction to tighten a fastener and whereby said teeth dig into the surface of the workpiece when said washer is rotated in a direction to loosen a fastener, and the inner rim edge of said central opening at said second end face being cold formed with a ring of long narrow notches each having a shallow end and a deep end formed by a generally helical surface inclined inwardly toward said first end face at an obtuse angle to said washer axis and lying close to and generally radially outside an imaginary similarly inclined helical surface which helical surface has a pitch circumferentially of said rim edge of the order of double the thread pitch of the fastener with which said washer is to be used, the end face of said notches at the deeper end thereof lying in a generally radial plane of said washer, and the lateral edges of said long helical surface of said notches converging and merging with one another at the rim edge of said central opening.

Claim 8

A lock washer comprising a continuous ring punched from strip metal of uniform thickness and substantially harder than the workpiece against which said ring is to be compressed in the assembly environment thereof, said washer having first and second end faces and a generally cylindrical central opening major portions of which have an axial length measured from one end face thereof not materially less than half the washer thickness and a non-circular wrench-engageable outer periphery, said first end face of said washer being upset to provide a ring of low-height teeth having a sharp edge extending generally radially thereof with one face of each inclined acutely and the other face lying generally in an axial plane whereby said teeth are adapted to cam over the surface of a workpiece when said washer is rotated thereover in a direction to tighten a fastener and whereby said teeth dig into the surface of the workpiece when said washer is rotated in a direction to loosen a fastener, and the inner rim edge of said central opening at said second end face being cold formed with a ring of long narrow notches each having a shallow end and a deep end formed by a generally helical surface inclined inwardly toward said first end face at an obtuse angle to said washer axis and lying close to and generally radially outside an imaginary similarly inclined helical surface which helical surface has a pitch circumferentially of said rim edge of the order of double the thread pitch of the fastener with which said washer is to be used, the end face of said notches at the deeper end thereof lying in a generally radial plane of said washer, and the lateral edges of said long helical surface of said notches converging and merging with one another at the rim edge of said central opening.

Claim 9

A lock washer as defined in claim 6 characterized in that said washer is dished as an incident to the punching of the said central opening from strip metal with said first end face being convex and said second end face being concave.

Claim 10

A lock washer as defined in claim 6 characterized in that the outer periphery of said washer includes two overlapping sets of hexagonally shaped surfaces lying in planes substantially parallel to the axis of said washer.

Claim 11

A lock washer as defined in claim 6 characterized in that said first washer end face is convex and said second end face is concave.

Claim 12

A self-locking vibration-proof fastener comprising a threaded shank having a wrench-seating retainer means at one end thereof, said retainer means having a frusto-conical surface sloping inwardly toward the axis of said threaded shank at an obtuse angle with the smaller end of said frusto conical surface substantially merging with said shank and having a ring of shallow teeth each having a generally radial face and a relatively long helical face having a pitch substantially in excess of the pitch of said shank threads, a wrenchable lock washer encircling said shank having an axial bore fitting loosely about said threaded shank, substantial portions of said bore on the end half thereof adjacent said frusto-conical surface being generally cylindrical, the rim edge of said bore adjacent said ring of shallow teeth on said retainer means having a ring of similar long shallow notches of varying depth circumferentially of said rim edge adapted to internest partially with the leading higher end of a respective one of said shallow teeth on said retainer means, said notches having a long generally helical surface having a pitch substantially in excess of the pitch of said shank threads and merging at the deeper end thereof with a generally radially disposed end wall surface, the lateral edges of said end wall and of said helical surface converging and merging with the rim edges of said washer bore at the respective opposite ends of said notches, the deeper end portion of said teeth on said retainer means having load bearing contact with the shallow end of a respective one of said notches in an area immediately adjacent the rim edge of said cylindrical bore and adjacent the sidewall of said threaded shank as the generally radial faces of said teeth engage said generally radial end wall of said notches whereby the tightening of said fastener loads said washer in hoop tension from a plurality of areas located about the periphery of said washer substantially at the rim edge of said cylindrical bore, and the end face of said washer remote from said notches having a ring of row-height sharp-edged barblike teeth extending generally radially thereacross with one face of each inclined acutely and the other face inclined obtusely to said one end face and in directions to cam said washer over the surface of a workpiece as said fastener is wrenched to tighten the same and to dig into the surface of the workpiece upon any tendency of the fastener to rotate in a loosening direction.

Claim 13

A self-locking vibration-proof fastener comprising a threaded shank having a wrench-seating retainer means at one end thereof, said retainer means having a frusto-conical surface sloping inwardly toward the axis of said threaded shank at an obtuse angle with the smaller end of said frusto conical surface substantially merging with said shank and having a ring of shallow teeth each having a generally radial face and a relatively long helical face having a pitch substantially in excess of the pitch of said shank threads, a wrenchable lock washer encircling said shank having an axial bore fitting loosely about said threaded shank, substantial portions of said bore on the end half thereof adjacent said frusto-conical surface being generally cylindrical, the rim edge of said bore adjacent said ring of shallow teeth on said retainer means having a ring of similar long shallow notches of varying depth circumferentially of said rim edge adapted to internest partially with the leading higher end of a respective one of said shallow teeth on said retainer means, said notches having a long generally helical surface having a pitch substantially in excess of the pitch of said shank threads and merging at the deeper end thereof with a generally radially disposed end wall surface, the lateral edges of said end wall and of said helical surface converging and merging with the rim edges of said washer bore at the respective opposite ends of said notches, the deeper end portion of said teeth on said retainer means having load bearing contact with the shallow end of a respective one of said notches in an area immediately adjacent the rim edge of said cylindrical bore and adjacent the sidewall of said threaded shank as the generally radial faces of said teeth engage said generally radial end wall of said notches whereby the tightening of said fastener loads said washer in hoop tension from a plurality of areas located about the periphery of said washer substantially at the rim edge of said cylindrical bore, and the end face of said washer remote from said notches having a ring of row-height sharp-edged barblike teeth extending generally radially thereacross with one face of each inclined acutely and the other face inclined obtusely to said one end face and in directions to cam said washer over the surface of a workpiece as said fastener is wrenched to tighten the same and to dig into the surface of the workpiece upon any tendency of the fastener to rotate in a loosening direction.

Claim 14

A self-locking fastener as defined in claim 10 characterized in that the bore of said washer is sized to have a loose fit over said threaded shank, and radially narrow keeper ring means having a forced fit over said shank adjacent said one end face of said washer and effective to hold said washer assembled thereto in the area closely adjacent said retainer means.

Claim 15

A self-locking fastener as defined in claim 11 characterized in that said end of said opening adjacent said sharp-edged teeth is countersunk to accommodate said keeper ring means.

Claim 16

A self-locking fastener as defined in claim 10 characterized in that said washer is dished with the end thereof having said sharp-edged teeth being convex and the other end face being concave.

Claim 17

A self-locking fastener as defined in claim 10 characterized in that said threaded shank is a cap screw.

Claim 18

A self-locking fastener as defined in claim 14 characterized in that the retainer means of said cap screw is provided with a hexagonal wrench-seating well axially thereof.

Claim 19

A self-locking fastener as defined in claim 10 characterized in that said retainer means is integral with one end of said threaded shank.

Claim 20

A self-locking fastener as defined in claim 10 characterized in that said ring has a hoop tension strength capability in excess of the design load strength capability of said threaded shank.

Claim 21

A self-locking fastener as defined in claim 10 characterized in that said washer has a punched central bore, a punched non-circular outer periphery and an axially dished configuration with the convex face thereof remote from said retainer means and the concave face thereof adjacent said retainer means.

Claim 22

A self-locking fastener as defined in claim 18 characterized in that the outer ends of said sharp-edged teeth in the convex end face of said washer feather out and merge with the outer peripheral portion of said convex surface.

Claim 23

A self-locking vibration-proof fastener comprising a threaded shank having retainer means at one end of substantially larger diameter than said shank and formed with a wrench-engaging surface, the end of said retainer means facing toward the shank threading having a generally conical surface portion with the smaller end thereof merging with the shank sidewall and an inclined surface extending therefrom and terminating in formed with low height camming teeth having generally radial shoulders interconnected circumferentially of said conical surface by radially wide helical surfaces having a pitch substantially greater than one pitch of said threaded shank threads, a lock washer embracing said shank having a punch-formed generally cylindrical central bore and a punch-formed wrench-engaging periphery, said washer being of sufficient size and strength to develop the full design strength of said threaded shank as said washer is placed in high hoop tension stress by the tightening of said threaded shank with respect to a workpiece bearing against a first face of said washer, a first end of said washer having low-height barb-like teeth substantially harder than the workpiece to be clamped thereagainst and shaped to glide over the workpiece surface as said fastener is tightened and to dig into the workpiece upon any tendency of counter-rotary movement of said washer, and rim edge of said punch-formed cylindrical bore remote from said barb-like teeth having a ring of long shallow notches arrnaged generally end to end thereabout each having a relatively deep shouldered leading end and an inclined surface extending therefrom and terminating in a shallow trailing end, said trailing ends providing load bearing surfaces located substantially on the rim edge of said cylindrical bore closely adjacent the leading deep end of an adjacent one of said notches, the lateral edges of the inclined surfaces of said notches converging to merge with the rim edge of said central bore in an area thereof close to the deep end of an adjacent one of said notches, and the load bearing surfaces of said notches being closely adjacent the sidewall of said shank and in contact with the trailing end portion of a respective helical surface of at the deeper ends of said camming teeth on said retainer means as said fastener is being tightened and cooperating therewith to place said washer under high hoop tension as the fastener approaches a fully tightened condition.

Claim 24

A self-locking vibration-proof fastener comprising a threaded shank having retainer means at one end of substantially larger diameter than said shank and formed with a wrench-engaging surface, the end of said retainer means facing toward the shank threading having a generally conical surface portion with the smaller end thereof merging with the shank sidewall and an inclined surface extending therefrom and terminating in formed with low height camming teeth having generally radial shoulders interconnected circumferentially of said conical surface by radially wide helical surfaces having a pitch substantially greater than one pitch of said threaded shank threads, a lock washer embracing said shank having a punch-formed generally cylindrical central bore and a punch-formed wrench-engaging periphery, said washer being of sufficient size and strength to develop the full design strength of said threaded shank as said washer is placed in high hoop tension stress by the tightening of said threaded shank with respect to a workpiece bearing against a first face of said washer, a first end of said washer having low-height barb-like teeth substantially harder than the workpiece to be clamped thereagainst and shaped to glide over the workpiece surface as said fastener is tightened and to dig into the workpiece upon any tendency of counter-rotary movement of said washer, and rim edge of said punch-formed cylindrical bore remote from said barb-like teeth having a ring of long shallow notches arrnaged generally end to end thereabout each having a relatively deep shouldered leading end and an inclined surface extending therefrom and terminating in a shallow trailing end, said trailing ends providing load bearing surfaces located substantially on the rim edge of said cylindrical bore closely adjacent the leading deep end of an adjacent one of said notches, the lateral edges of the inclined surfaces of said notches converging to merge with the rim edge of said central bore in an area thereof close to the deep end of an adjacent one of said notches, and the load bearing surfaces of said notches being closely adjacent the sidewall of said shank and in contact with the trailing end portion of a respective helical surface of at the deeper ends of said camming teeth on said retainer means as said fastener is being tightened and cooperating therewith to place said washer under high hoop tension as the fastener approaches a fully tightened condition.

Claim 25

A self-locking fastener as defined in calim 20 characterized in that said one washer face is convex and in that the other washer face is concave.

Claim 26

A self-locking fastener as defined in calim 20 characterized in that said one washer face is convex and in that the other washer face is concave.

Claim 27

A self-locking fastener as defined in claim 21 characterized in that said barb-like teeth have a generally radially disposed sharp edge merging with said convex surface inwardly of the outer periphery of said washer.

Claim 28

A self-locking fastener as defined in claim 21 characterized in that the end of said central bore merging with said convex surface is provided with a shallow radially narrow annular recess, and a keeper ring having a press fit over said threaded shank and cooperating with said annular recess to hold said washer loosely assembled to said shank prior to the assembly of said fastener to a workpiece.

Claim 29

A self-locking fastener as defined in claim 20 characterized in that the load bearing washer surfaces include spacedapart unnotched portions of the rim edge of said central bore.

Claim 30

A self-locking fastener as defined in claim 20 characterized in that the bottom portions of said notches are inclined inwardly toward the axis of said central bore along lines intersecting said axis outwardly beyond the remote washer end face.

Claim 31

A self-locking fastener as defined in claim 20 characterized in that the major portion of the surface of said central bore is generally cylindrical.