Patent GB-1397108-A (GB)
Title: Cold pressure welding tool
IPC: B23K23/00
Filed: 1972-12-21
Abstract: 1397108 Welding by pressure KELSEYHAYES CO 21 Dec 1972 [12 Jan 1972] 59186/72 Heading B3R A hand held cold pressure welding tool comprises a housing assembly 12 to be held in an operator's hand, welding dies 18 for gripping and upsetting pieces to be welded, a handle 13 supported for movement relative to the housing assembly and force amplifying means carried by the housing assembly and operatively interposed between the handle and the dies for amplifying force exerted upon the force amplifying means by the handle and for applying such amplified force to cause the dies to grip and upset the pieces during a welding operation, force limiting means being provided for limiting the force applied to the dies by the force amplifying means. A tool for cold pressure welding cables comprises a housing 12 at one end of which is the handle 13 for operating an hydraulic pump 16 which feeds an hydraulic motor 17 for effecting operation of a die set 18 at the other end of the housing. The end of the housing remote from the pump 16 comprises a pair of members 19, 21 pivoted together at 28 and held releasably closed by a latch device 32 including a latching member pivoted to the member 19 and engaging a shoulder 39 on the member 21. The die set 18 comprises a first pair of dies 105, 106 and a second pair of dies 107, 108, the dies 106, 108 being located in the housing member 19 and the dies 105, 107 being located in the member 21. The mating surfaces of the dies 105, 106 are provided with grooves 109, 111 to grip a cable and dies 107, 108 have grooves 112, 113 to grip another cable and flash receiving cavities are provided in the facing die surfaces 114, 115, 116, 117. A projection 121 on the die 105 engages a recess 119 in the die 106 when the dies are sufficiently close and a similar projection and recess are provided on the dies 107, 108. The dies 105, 107 are held between plates 124, 125 secured to a portion 128 of a piston 77 forming part of the motor 17 and having a surface area greater than that of the pump piston 48 and have surfaces 151, 152 engaging V surfaces 153, 154 on the portion 128 and dies 106, 108 are held between plate 136, 137 fixed to a V block 139, faces on the dies engaging faces on the V block and guide pins on the plates engaging grooves on the dies. Inclined surfaces 182, 183 on dies 106, 108 are engaged by a spring pressed plunger 186 in the V block 139 and inclined surfaces 171, 172 on the dies 105, 107, are engaged by a spring pressed plunger 175 in the piston 77. The piston 77 is located in a bore 76 in the housing member 21 and is spring urged to the right in Fig. 2. The bore 76 communicates with a smaller bore 75 in the member 21 which latter bore is intersected by two bores 78, 79, the former containing an adjustable pressure relief valve 81 allowing flow into a reservoir 88 and the latter bore containing a release valve assembly 95. The bore 75 is connected by a tube 70 to a pump housing 43. A bore 47 in the housing 43 receives the pump piston 48 connected to the handle 13 pivoted at 14 to the housing and the end of the bore 47 is intersected by a bore 66 connected to the tube 70 and the end of reservoir 88 remote from the relief valves communicates with the bore 47. When the piston 48 is raised by lifting the handle 13 fluid fills the bore 47 from the reservoir 88. A cable gripping device is provided at each side of the die set and comprises gripping fingers 211, 212 having depending pins. In operation with the dies retracted cables are inserted into the cavities defined by the grooves 109, 111, 112, 113, through the gripping fingers into abutment. The release valve 95 is screwed shut and the handle 13 is pumped to deliver hydraulic fluid into the bore 76 to move the piston 77 to the left in Fig. 2. The V surfaces of the piston and block 138 cause the die pairs 105, 106 and 107, 108 to close and grip the cables. Continued pumping exerts sufficient pressure to retract the plungers 175, 186 against their springs and to urge the die pairs together to upset the cables. When the pre-set pressure is reached the relief valve 81 opens to limit the pressure exerted upon the cables. The valve 95 is opened to relieve the pressure and the dies retract. Further upsets are made on the same cables until a good weld is made. Then the latch 32 is released and the welded cables removed and if necessary the dies may be replaced.