Patent GB-761326-A (GB)
Title: Improved method and apparatus for making branched pipe fittings
Inventor: STANTON CHARLES BERNARD
IPC: B21C37/29
Filed: 1954-11-10
Abstract: 761,326. Making branched-pipe fittings. IMPERIAL CHEMICAL INDUSTRIES, Ltd. Nov. 10, 1954, No. 32515/54. Addition to 700,855. Classes 83 (2) and 83 (4). Stamping.-An improvement or modification of the apparatus for forming. branched-pipe fittings from tubular blanks as disclosed in the parent Specification, comprises support means, a plurality of complementary die members carried by said support means, said die members together defining a main cavity and at least one branch cavity, plunger means movable in said main cavity for longitudinally compressing a blank disposed therein, means for applying a high hydraulic pressure through said plunger means to the interior of the blank, a support member movable in said branch cavity and means responsive to the operation of the plunger moving means for controlling the outward movement of said support member and for moving said support member inwardly to eject a formed fitting from the said die members. The apparatus comprises a base portion 1 carrying a supporting plate 5 on which is mounted a die housing 9. Four tie bars 11 extend through the die housing. The die is in two parts, a fixed rearward portion 13 and a movable forward portion 19 each having semicylindrical channels 21, 23 which mate to form the main die cavity. The rear die portion 13 contains the branch cavity arranged normal to the main die cavity. The die portion 19 is connected to a reciprocable block 27 mounted in tracks 29 (Fig. 5), said block supporting a part roller 31 on a shaft 33 which also carries one end of a toggle link 35. The other end of link 35 is mounted on a shaft 37 which also carries one end of a link 39. The other end of link 39 is mounted on a shaft 41 carried by a part roller 43 at the bifurcated end portion of a block 45. The shaft 37 carries a cam roller 47 which co-operates with a cam track 49 in a camplate 51 pivotally mounted on a shaft 53 supported on the machine frame. One end of a link 55 of a second toggle mechanism is mounted on a shaft 57 carried by the plate 51 and the other end of the link is mounted on a free shaft 59 which also carries one end of a link 61, the other end of which is'mounted on a shaft 63 freely passing through the part 65 of the machine frame. The shaft 63 carries an operating handle 67 and the free shaft 59 carries a depending arm 69, the lower end of which carries a roller 71. The die portion 19 is adjustable by means of an inclined slidable adjusting block 73 movable by an adjusting screw 75. A tubular channel coaxial with the main die cavity extends from side to side of the die housing 9 and accommodates inserts 81, 83 for pistons 85 and 87 having reduced leading portions 97, 99. The outward ends of the pistons are secured to blocks 103, 105 having inclined surfaces which co-operate with inclined surfaces on depending. arms 107, 109 secured to the ram member 3 and slidable in guideways 115, 117. Two hydraulic pressure vessels 119, 121 are disposed on the die housing 9 and have cylinders 123, 125 connected by a pipe 127. The vessels 119, 121 support a storage tank 129 which maintains a constant head of air-free liquid in the cylinders. Pistons 137, 139 associated with the vessels and cylinders are secured to the ram member 3 and when the pistons are in their uppermost position liquid is able to flow from the tank to the cylinders. The cylinder 123 is connected to a pressure-relief valve 147 and the cylinder 125 to one side of a twoway valve 157 associated with a pressure indicating device 159. The other side of the two-way valve is connected to a supply of lowpressure fluid. The outlet pipe 169 of the valve is connected to the space 95 between the piston 87 and the insert 83. The piston 87 has a diametral bore 171 and a longitudinal bore 173 which opens into the main die cavity. The branch cavity 25 contains a slidable plunger 175 connected by a spring-loaded peg 177 to ahead portion 181 having a semi-cylindrical recess. The end of the plunger remote from the head portion 181 is provided with a roller 183 which co-operates with an inclined surface of an arm 187 connected to the ram 3 by means of a lost-motion connection. The arm 187 is guided in guideways 189. When the die is open, a spring 185 projects the head portion 181 slightly forwardly of the fixed rearward portion of the die and thus acts as an ejecting means. The cylindrical blanks are fed one at a time to the die from an inclined shoot 191 the end of which is associated with a spring-loaded plunger 193 which co-operates with an arm 199 of a lever pivoted on a plate 201 the other arm 203 of the lever acting as an operating handle. A re-entrant spring 207 on the plunger closes the end of the shoot and tracks 209 in front of the die portion 19 receive the fed blank. To open the die after the forming operation, the ram 3 is provided with an hooked arm 21 (Fig. 4), which engages during its upward movement with a projection 215 on one arm 217 of a bell-crank lever mounted on the shaft 53. The other arm 219 of the lever co-operates with the roller 71 on the arm 69. In operation, the handle 203 is moved to drop a blank on to the tracks 209 and the spring 207 will urge the blank into the semi-cylindrical recess. Next the handle 67 is operated to straighten the toggle mechanism and close the die. Projection of the head portion 181 dimples the wall of the blank and prevents undue trimming during the forming operation. When the die is closed low-pressure water is supplied to the interior of the blank and the ram is moved downwardly. The plungers 85, 87 move inwardly and engage the blank and traps the low-pressure water within the blank to prevent turbulence when the high-pressure is applied. Pistons 137, 139 have already entered cylinders 123, 125 displacing liquid to operate the two-way valve and cut-off the low-pressure fluid and supply the high-pressure fluid. During formation of the branch B it is supported by the head portion 181 which retracts at a constant rate and thus controls the wall thickness of the branch. As the ram moves upwardly the die opens and the plungers withdraw from the formed fitting which is ejected by the spring- loaded head 181.