# US 5,700,121 A · Self-locking nut > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,700,121 A - Document ID: US5700121A - Status: Granted - Kind: A - Application number: 08/689,246 - Filed: 1996-08-07 - Granted: 1997-12-23 - Earliest claimed: 1996-08-07 - Inventors: Antonio Minola - Web page: https://patentgrep.com/patent/US5700121A ## CPC - F16B 39/14: made of thin sheet material or formed as spring-washers (locknuts per se made of thin sheet metal F16B37/02) - F16B 37/02: made of thin sheet material (fastening to surfaces F16B37/04 {; used as lock-nuts F16B39/14}) - F16B: DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING (couplings for transmitting rotation F16D) ## Abstract The self-locking nut comprises an hexagonal outer case (10) having front and rear open faces, and a set of cup-shaped or tapered spring members (14a, 14b) having threaded bores (17) axially aligned with the front and rear openings of the case (10). At least one of the tapered spring members (14a) has side edges (18) inwardly rounded and is provided with deflection legs (19) which extend outwardly to engage the internal corners between the side walls (11) of the case (10). A braking washer (20) may be optionally provided inside the case (10) to prevent the reverse rotation of the nut caused external stresses; the braking washer (20) is provided with a large central hole (21) having inwardly extending protrusion (22) ending in correspondence of the average diameter of the thread (17) of the spring members (14a, 14b) of the nut. ## Claims ### Claim 1 A self-locking nut comprising an outer case having open front and rear sides, and peripherally-arranged side walls, a set of tapered spring members, each having a threaded central bore, being stacked inside the case, and lugs inwardly bent from the side walls to retain the spring members in the outer case, wherein said set of spring members includes at least one first spring member comprising inwardly rounded peripheral edges and angularly spaced deflection legs, each of said legs radially protruding from each first spring member to engage a corresponding corner of the peripheral walls of the case. ### Claim 2 (depends on 1) A self-locking nut according to claim 1 wherein said spring members are identically-shaped, said case being hexagonal. ### Claim 3 (depends on 1) A self-locking nut according to claim 1 wherein, said set of tapered spring members comprises at least one second spring member having side edges parallel to the peripheral walls of the case said at least one second spring member being located at said open front side, said at least one first spring member being positioned to the rear of said at least one second spring member, between the at least one second spring member and said open rear side of the case. ### Claim 4 (depends on 1) A self-locking nut according to claim 1, wherein said set of tapered spring members further comprises hexagonal spring members, said hexagonal spring members having rectilinear edge portions matching the peripheral walls inside the case, said at least one first spring member arranged between said hexagonal spring members. ### Claim 5 (depends on 1) A self-locking nut according to claim 1 wherein the set of tapered spring members comprises differently shaped spring members having the same thickness and different load-deflection ratio. ### Claim 6 (depends on 1) A self-locking nut according to claim 1, wherein the case comprises a conical front face converging in an opposite direction to a taper of the set of tapered spring members inside the case. ### Claim 7 (depends on 1) A self-locking nut according to claim 1 wherein each of the peripheral walls of the case includes a slotted portion longitudinally extending along the wall. ### Claim 8 (depends on 1) A self-locking nut according to claim 1 comprising lugs members longitudinally extending and co-planary arranged to the side walls of the case. ### Claim 9 (depends on 1) A self-locking nut according to claim 1 comprising anti-rotational braking means inside the case, said braking means comprising a washer member having a central hole larger than a threaded bore of the spring members, and protrusions inwardly extending from the edge of the central hole to engage the threads of a bolt on which the nut is screwed. ### Claim 10 (depends on 9) A self-locking nut according to claim 9 wherein said washer member comprises a hexagonal outer edge engaging the side walls inside the case, said protrusions being round and angularly spaced. ### Claim 11 (depends on 10) A self-locking nut according to claim 10 wherein the washer member is made of a flat sheet material having a thickness smaller than the thickness of the tapered spring members inside the case. ### Claim 12 (depends on 11) A self-locking nut according to claim 11, wherein the washer member has a thickness of at most a thickness of an average diameter (Dm) of a thread in the threaded bore of the tapered spring members of the nut.