| 摘要 |
1,191,567. Wrenches. N. C. DAHL. 19 July, 1968 [24 July, 1967], No. 34695/68. Heading B3N. [Also in Division F2] In a wrench for use with nuts or bolts which have as described in Specification 1,189,031 a quantity of electrically-conductive material 18 arranged to be extruded therefrom when tightened to a predetermined extent, a contact point 24 connected to an electrical circuit is disposed in one of the wrench surfaces which engages the bolt head or nut 10 so as to be contacted by the extruded material 18 to complete the circuit when the nut or bolt is tightened. As shown, a socket wrench 22 has the contact point 24 received in the surface of the socket wall in such a position as to be adjacent a groove 14 formed in the nut 10 and containing the material 18 which may be a polymeric material having a filling of iron filings. When the nut is tightened a portion 16 thereof between the groove 14 and an internal groove 12 deforms plastically in shear to close the groove 14 and extrude the material 18, so that a circuit including an insulated wire 26 connected to the contact point 24 and a wire 28 connected to the socket is completed to light an indicator lamp, sound a bell or horn, or to shut off the power if the wrench is power-driven. The wrench may be an open-ended or box wrench. |
