Patent GB-602883-A (GB)
Title: Improvements in or relating to welding method and apparatus
IPC: B23K9/18
Filed: 1945-06-25
Abstract: 602,883. Making propellers. CURTISSWRIGHT CORPORATION. June 25, 1945, No. 16121. Convention date, April 29, 1944. [Classes 83 (ii) and 83 (iv)] [Also in Groups XXXV and XXXVII] Uniting by fusion.-In a method of fusion welding comprising feeding a weld rod towards the work while it is moved along the seam, a function of the welding operation, defined as the rate of traverse of the weld rod carriage along the seam, is controlled in accordance with differing transverse dimensions of the joint to be welded. The welding rod is automatically fed to the work by apparatus mounted on a carriage which is movable longitudinally of the work table. The speed of the carriage may be controlled by a cam-plate so that it may be progressively slowed down in order to produce joints in which the cross-section of weld metal and its dimensions gradually increase. Alternatively, the carriage may be speeded up; producing, thinner deposits of welding metal. The welding rod R, Fig. 1, and its reel 7 are supported on a bracket 6 which is pivoted on a standard 5, mounted on a carriage 1. The carriage is driven by a motor 24, Fig. 4, which is geared to one axle of wheels 3 which run on tracks 4. A tubular section 27a extends from the motor housing and contains an insulated block 27b on which is mounted two contact strips 28, 29 connected into the motor control circuit by conductors 28b, 29b. The motor armature carries a disc 31 on which is mounted a resilient arcuate member 30, retaining balls 32 and urged into contact with an insulated button by a spring 33. A cap 34 is screw-threaded to the extension 27a and carries a threaded tube 35 which may be locked in any position by a nut 35a. Slidable in tube 35 is a rod 36, tapped to receive a lock screw 37 which is held in engagement with a cam 38a of an arm 38 by a spring 39. The arm is pivoted at 38b on a bracket 39<SP>1</SP>, has limited movement between a bar 39b and carries a roller 38c held against a cam-plate 40 by a spring 41 so that as the roller swings the arm about its fulcrum due to the contour of the strip 40, the cam face 38a transmits longitudinal motion to rod 36 and varies the setting of the contact strips 28, 29. The base speed of the carriage may be determined by the initial spacing of the contacts which can be varied by rotating cap 34 or by manual operation of tube 35. As the armature revolves, the balls 32 move outwards under centrifugal force and cause the arcuate member to be strained to the left against the action of spring 33 allowing contacts 28, 29 to open and interrupt the motor supply. The motor slows down until the force transmitted to the arcuate member by balls 32 is overcome by spring 33 when the contacts are again closed and the motor re-energized. If the configuration of strip 40 is such that the space between contacts 28, 29 is gradually widened, as the carriage moves along the work, then the driving motor is cut out for progressively longer periods and movement of the carriage is correspondingly slower, but is maintained by the re-energization of the motor at the instant the contacts close. In the reverse case, the motor may be speeded up by virtue of the contact strips being gradually brought closer together. A housing 10 contains rollers 9, Fig. 1, which feed the welding rod and are rotated by a motor 8, mounted on bracket 6. The housing carries a support 11 having an arm 12 and a roller 13 which coacts with a guide rail 14 to keep the tip of the weld rod in position over the adjoining grooves in work W. Welding current is supplied from the secondary of a transformer 21 to contacts 15, which engage the welding rod, through the work W and conductor 22 to the return side of the secondary. A. continuous supply of flux is maintained by a hopper 19, attached to housing 10, and is fed into a conical funnel 16 through a passage 20. The invention is particularly described with reference to the manufacture of propeller blades wherein grooves g<SP>1</SP>, Fig. 5, and grooves g are to be joined; the thickness of the material and dimensions of the groove gradually increasing from the tip of the blade towards the shank s. In a modification, Fig. 10, the speed of motor 24 is controlled by a pair of cam-plates 57  defining a passage in which a roller 56 may be moved. The roller is supported by an arm 55 secured to rack teeth 53, which engage a pinion 52 attached to the tube 35 so that as the roller is displaced the pinion is turned anti-clockwise, rotating cap 34 and widening the space between contacts 28, 29.