# US 4,391,431 A · Device for tightening coarse thread connections > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,391,431 A - Document ID: US4391431A - Status: Granted - Kind: A - Application number: 06/243,901 - Filed: 1981-02-23 - Granted: 1983-07-05 - Earliest claimed: 1979-06-27 - Inventors: July S. Maximov - Web page: https://patentgrep.com/patent/US4391431A ## CPC - B25B 29/02: Bolt tensioners - B25B: TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING, OR HOLDING ## Abstract A device for tightening coarse thread connections comprises a pressure element (1), a tension element (2) and a power wedge (3) having a screw drive. Provided in the tension element (2) is a wedge groove (10), whereas the pressure element (1) has arranged essentially coaxially with the wedge groove (10) through grooves (13), the power wedge (3) passing through the grooves (10 and 13). The pressure element (1) is in the form of a hollow body accommodating the tension element (2) carrying rotatably secured thereto a connecting piece (16) having a threaded bore (17) for fastening with a threaded connectable piece. Apertures (22) are provided in the pressure element (1) in the area adjoining the connecting piece (16). Walls of the through grooves (13) of the pressure element (1) define a guide receiving straight working surface (12) of the power wedge (3). ## Claims ### Claim 1 A device for tightening a connection member extending between and interconnecting two connectable pieces, said connection member having a threaded member protruding from an opening in one of the connectable pieces, said device comprising a pressure element positionable so as to thrust against said one of the connectable pieces, a tension element positionable on the threaded member and having a wedge groove, a power wedge accommodated in the wedge groove and acting against the pressure element thereby producing tension in the threaded member, a screw drive for the power wedge disposed on the presure element, the pressure element being in the form of a hollow body provided with through grooves arranged coaxially with the wedge groove and accommodating the tension element, the tension element carrying an axially rotatable connecting piece having an axial threaded bore for fixing the connecting piece on the threaded member, the pressure element being provided in an area adjoining the connecting piece with apertures, walls of the through grooves arranged coaxially with the wedge groove of the tension element defining a guide receiving a straight working surface of the power wedge. ### Claim 2 (depends on 1) A device as claimed in claim 1, characterized in that the axial threaded bore of the connecting piece accommodates a replaceable threaded sleeve member, an outer surface of the connecting piece being provided with drillings for facilitating rotation of the connecting piece. ### Claim 3 (depends on 1) A device as claimed in claim 1, characterized in that it is further provided with at least one intermediate sleeve placed, after having been screwed onto the threaded member, in the axial bore of the connecting piece of the tension element and secured therein by means of a bayonet joint, the intermediate sleeve having a cylindrically shaped axial end piece and a projection rotatable by a wrench, the connecting piece of the tension element having an axial bore to receive the end piece of the intermediate sleeve and a lever passing through an aperture of the pressure element. ### Claim 4 (depends on 1, 2, 3) A device as claimed in one of claims 1 to 3, characterized in that inserts engageable by the power wedge are accommodated in the wedge groove of the tension element and in the through grooves of the pressure element arranged coaxially relative to the wedge groove. ### Claim 5 (depends on 1, 2, 3) A device as claimed in one of claims 1 to 3, characterized in that the pressure element is made up of two parts interconnected by a threaded connection. ### Claim 6 (depends on 5) A device as claimed in claim 5, characterized in that one of the parts of the pressure element is adapted to be thrust against one of the connectable pieces and provided with a spherical abutment, the center of the sphere thereof being disposed on the center line of the connecting piece and the center line of the threaded member. ### Claim 7 (depends on 6) A device as claimed in claim 6, characterized in that the spherical abutment is joined to the pressure element via a resilient spacer. ### Claim 8 A device for applying tension to a threaded stud piece, the stud piece being used to interconnect two connectable pieces and having a threaded end portion protruding from one of the connectable pieces, said device comprising: a pressure element having an open end, an axially-extending hollow portion extending inwardly from the open end, and a wedge receiving groove formed in an end portion of said pressure element opposite said open end and extending transversely to the axis of the hollow portion, the open end of the pressure element being positionable adjacent a surface of one of the connectable pieces so that the threaded end portion of the stud piece is received in the hollow portion of said pressure element; a tension element having a connecting piece extending into the hollow portion engageable with the threaded end portion of the stud piece, and a wedge groove alignable with the wedge receiving groove of said pressure element; a power wedge positionable in said wedge groove and said wedge receiving groove so that movement of said power wedge in a given direction urges said tension element away from the threaded end portion of the stud piece thereby applying tension to said threaded stud; and means carried by said pressure element for moving said power wedge in said given direction. ### Claim 9 (depends on 8) A device according to claim 8, wherein a nut is positionable on said threaded end portion between said surface of said one of the connectable pieces and said connecting piece, said pressure element having an aperture formed therein providing access to said nut so that the nut is movable into contact with said surface after tension has been applied to said threaded stud piece, said connecting piece being removable from said threaded end portion after contact between said nut and said surface. ### Claim 10 (depends on 8, 9) A device according to claim 8 or 9, further comprising an intermediate sleeve having an inner surface engageable with the threaded end portion of the stud piece and an outer surface engageable with said connecting piece, the outer surface of the intermediate sleeve and the connecting piece carrying complementary fastening elements so that the connecting piece is locked to the intermediate sleeve by relative rotation between said intermediate sleeve and said connecting piece. ### Claim 11 (depends on 8) A device according to claim 8, wherein said pressure element comprises a first part, a second part, and means for interconnecting said first part and said second part, said first part supporting said tension element and said second part being movable with respect to said first part after said connecting piece engages said threaded end portion so that an end of said second part comes into contact with said surface of said one of said connectable pieces. ### Claim 12 A device for tightening coarse thread connections formed in openings of two connectable pieces comprising: a threaded part positionable in openings of two connectable pieces and having a free end projecting from one of the connectable pieces; a nut screwed onto the free end of said threaded part so that a portion of the free end protrudes from the nut; a pressure element having a hollow body and resting on the one of the connectable pieces and receiving said free end of said threaded part; a tension element with a wedge groove located in the hollow body of said pressure element and fastened to the portion of the free end of the threaded part protruding from the nut; a power wedge with a screw drive positioned in the wedge groove of said tension element for acting upon said pressure element to produce tensioning of the threaded part, a shank portion of said tension element being positioned in the hollow body of the pressure element; a connecting piece mounted for rotation about its axis on said shrank portion, drillings being provided on an outer surface of said connecting piece, and an axial threaded bore formed in said connecting piece and adapted for screwing said connecting piece onto the portion of said end of the threaded part protruding from the nut; apertures provided in said pressure element opposite the portion of said connecting piece located at the end of the threaded part; and through bores provided in said pressure element in alignment with said wedge groove so that walls of said pressure element forming said through bores define a guide for a working surface of the power wedge. ### Claim 13 (depends on 12) A device as claimed in claim 12, further comprising a replaceable threaded sleeve member screwed into said threaded bore of the connecting piece for securing the connecting piece at the protruding portion of the end of the threaded part. ### Claim 14 (depends on 13) A device as claimed in claim 13, wherein a bore is provided in said shank portion of the tension element for accommodating balls therein, said device further comprising balls positioned in said bore for connecting said connecting piece to said shank portion of the tension element. ### Claim 15 (depends on 13) A device as claimed in claim 13, further comprising an intermediate sleeve engaged with the portion of the threaded part protruding from the nut, said intermediate sleeve being received in said axial threaded bore of the connecting piece; a bayonet joint effecting coupling of the connected piece with the intermediate sleeve; a cylindrical axial end piece having a projection to fit a wrench which has said intermediate sleeve; an axial bore provided in the connecting piece and adapted to accommodate an end piece of the intermediate sleeve; and a lever mounted on the connecting piece and passing through one of the apertures of the pressure element. ### Claim 16 (depends on 13) A device as claimed in claim 13, wherein the pressure element is formed by two parts interconnected by a thread joint, a portion of the pressure element thrusting against one of the connectable pieces being provided with a spherical abutment, the center of the abutment being disposed on the center line of the connecting piece and of the threaded piece, said device further comprising a resilient spacer, the abutment being joined to the pressure element via the resilient spacer.