Patent GB-852850-A (GB)
Title: Improvements in and relating to the welding of metallic tips to metallic bases
Inventor: NEWMAN REGINALD JAMES
IPC: B23K11/26
Filed: 1958-03-07
Abstract: 852,850. Making pen nibs; welding by pressure. JOHNSON, MATTHEY & CO. Ltd. Feb. 13, 1959 [March 7, 1958], No. 7435/58. Classes.83 (2) and 83 (4). In welding a metal tip to a metal base wherein the tip and base are brought into mutual contact and current is passed through the tip and base to melt metal of the base, the current passed through the tip and base is a single unidirectional impulse of predetermined short duration derived from a direct current supply source of substantially constant voltage and the welding circuit includes a contact make and break mechanism intermittently operable by the release of stored energy to close and open the circuit once during each operation of the mechanism. A machine for welding a tip to a pen nib blank comprises a base 2, Fig. 2, and wall 3 and externally of the wall is mounted a nib-clamping device 4, Fig. 1, and below this device a vertically movable tipholder 5. The clamp 4 and holder 5 are included in a welding circuit 6, Fig. 7, energized from a 12-volt battery 7 and including a variable resistance 8 and a pair of contacts 9, 10 adopted to be opened and closed by a timing device 11 having a pendulum 36. A block 12 on the base supports a shaft 15 carrying a pulley 16 by which the shaft is chain driven from a motor 17 having a band-braking device 17b to stop the motor when its circuit is de-energized. A cam 19 on the shaft engages a roller 20 on a rod 21 operating a tip hopper 22 such that operation of the rod causes a tip to fall via a shoot 22a into the holder 5. A cam 24 on the shaft actuates a valve controlling a supply of hydrogen to the welding area and has a surface 26, Fig. 4, to hold a stop 27 in a position to retain the pendulum in the normal raised position shown in Fig. 2. A'further cam 28 on the shaft engages a roller 29 on one end of an arm 30 the other end of which carries a pin 31 engaging a triangular beam 65 carrying the holder 5 and pivoted at 67 and 68 on a member 69 adjustable on a plate by screws 71, 72. The beam is biased upwardly by a spring 66. Between the cam 28 and wall 3 is a bearing block 32 in which is rotatable parallel to but offset from the shaft 15, a shaft 33 carrying a pair of adjustable cams 34, 35 and the pendulum 36. The pendulum and cam 35 are fixed on the shaft 33 and cam 34 is adjustably mounted on cam 35, cams 34 and 35 presenting large radius portions 34a, 35a, Fig. 5, and small radius portions 34b, 35b. A bracket 59 on the block 32 carries the fixed contact 9 and an arm 61 on a spring 60 fixed to the block carries the movable contact 10 and a roller 62 which engages the cams. When the roller rides on the larger portions the contacts open and when on the smaller portion the contacts close. A stop switch 40 for the motor 17 is mounted on the block 12 and has an operating arm 41 engaging the cam 19. In operation with the holder 5 lowered due to the cam 28, the pendulum in its raised position, contacts 9, 10 open, motor 17 braked and a tip in the holder the nib holder 4 comprising a part fixed to the wall 3 and a clamp member pivoted to the fixed part is opened and a nib blank is clamped therein. The brake is released and the motor started to rotate the shaft 15. Rotation of the cam 28 allows the beam 65 to rotate on its pivots 67, 68 and thus the holder 5 to rise under the action of spring 66 until the tip contacts the nib. Further rotation of shaft 15 cause cam surface 26 to allow retraction of stop 27 by its spring 27a and the pendulum is released to swing into a horizontal position shown in dotted lines in Fig. 4 where it is held by a spring catch 37. This movement rotates the cams 34, 35 so that the roller 62 moves over the small cam portions to close the contacts, the contacts remaining closed until the roller rides on the large portions when the contacts open. Closing of the contacts allows a current to pass from the battery to heat the tip and nib, the metal of which latter melts and the tip rises further under spring 66 until the holder 5 engages an adjustable micrometer stop 57 on the nib holder 4. Meanwhile the cam 24 has actuated the valve which allows hydrogen to flow about the weld. Continued rotation of the shaft 15 causes cam 28 to actuate the arm 30 and move the empty holder 5 downwards and brings a member 38 on the cam into engagement with a projection 39 on the pendulum which is swung up to its normal position to be held by stop 27. Finally switch 40 is actuated to stop the motor 17. The energy storage device may be a spring or weight.