GB663850A - Manufacture by electro-deposition - Google Patents

Abstract

663,850. Electrodeposition. ROSENQVIST, G. Feb. 13, 1948, No. 4251/48. [A Specification was laid open to inspection under Sect. 91 of the Acts, Feb. 13, 1948.] Class 41. [Also in Groups XIII and XXIV] A method of forming metal articles by electrodeposition includes the steps of electrodepositing metal to build up the desired thickness and simultaneously working the metal by repeatedly pressing against the exposed cathodic surfaces to displace metal particles relative thereto, the displacement being effected entirely within the exposed cathodic surface without any lateral displacement of metal particles to superimposed positions on said exposed cathodic surface. There may also be subsequent electrodeposition on selected areas of the cathode surface which are pressed in a direction deviating from a normal to the surface of working contact so as to induce lateral displacement of the metal particles to positions on the outside of the cathode surface, thereby entrapping plating solutions, a further layer of sound metal being then added by the method indicated above. In the application of heat, the entrapped moisture expands to form pockets in the structure. In the arrangement shown in Figs. 1, 1a znd 4, a frame 1 supports two mandrels 10 which are fed through openings into a tank 2 wherein they receive an electrolytic deposition of metal. The mandrels are slowly rotated about their longitudinal axes. The electrolyte in tank 2 is pumped from a storage tank 4. A carriage 64 running on rails 66 is driven slowly in the opposite direction to that of the mandrels by means which include an endless driven belt 78 provided with studs 80 engaging successively a hook 76 connected to the carriage 64. As the hook is disengaged from each stud, a spring 74 acts to move the carriage rapidly in the opposite direction. The carriage supports several vertically-reciprocating hammers 60 which strike the metal deposited on the mandrels. Each hammer 60 is slidably mounted in a bracket 62a and is connected by a rubber tubing 114 to one end of a crank 110 projecting from a shaft 102, which is rocked by a crank 100 carrying a ball follower 98 pressed against a hexagonal cam 96 on a driven shaft 94. Normally the end of the hammer is out of contact with the metal on the mandrel 10, but its momentum is sufficient to carry it into impact momentarily each time the follower 98 is at the lowest position on the cam 96. The removal of each electrodeposited metal tube from the mandrel is facilitated by the hammering and also by a clutch 136, Figs. 1a and 4a, which comprises metal rings 138 alternating with rubber rings 140. The clutch fits over the finished tube 12 on the outlet side of the machine and can move to the left but not to the right relatively to the tube. The clutch has a limited movement with the tube, determined by stops 150 and 152. The mandrel is provided at its inner end with an oversized rubber ring, which acts as a clutch so that the tube is carried along with the mandrel as it advances into the tank 2 but is freed therefrom as the mandrel is retracted. During such retraction, at first the tube 12 moves to the left and its edge is wedged in an opening in the end wall of the tank 2 so that the mandrel is shielded from the electrolyte. The clutch 136 then abuts the stop 150 and the tube is held as the mandrel is moved to the left. The mandrel at its outer end is insulated from the electrolyte by rubber tubing. Means are provided for minimizing leakage of electrolyte and collecting any electrolyte leaking through the end walls of the tank where the mandrel and tube project. The tank 2 is provided with copper scrap 6, Fig. 4, functioning as the anode and retained by perforate walls of baskets 8. Anode sludge collecting near the bottom of the tank is removed by means of reciprocating rods 226 mounted on bent wires which stir the sludge and facilitate its escape through holes 221 and through drains 204. In the construction shown in Figs. 21 and 26 the metal tube, in addition to being struck momentarily by hammers 60, is also subjected to pressure from etched glass rollers 406, each of which is brought into operation by means of an electromagnet. The electromagnets are energized from a further source 410 in a circuit which includes a pattern cylinder 420 adapted at times to make contact with one of a series of points 422 on a rod 426. The pattern cylinder is mounted on the end of the mandrel 10<SP>1</SP>. The pressure of the glass roller causes lateral displacement of the electrodeposited metal such that on subsequent heat treatment of the tube entrapped moisture causes expansion to produce pockets such as the pockets 520, Fig. 28, the number and dimensions of the pockets depending upon the form of the pattern cylinder. In a further arrangement shown in Figs. 13 and 14, the product is a continuous sheet of metal formed on a drum 300 and intermittently advanced through a tank 305. The sheet is hammered when it is stationary. The drum 300 is rotated by a ratchet 308<SP>1</SP> and pawl 314, the pawl being carried by the core of a solenoid 318. The circuit of the solenoid includes a switch comprising a contact arm 322 and an element 324 pivotally connected to a diaphragm 326, and pivoted at 328 eccentrically of a shaft 330 driven by means of a belt and pulley (not shown. When the switch is closed the ratchet 308<SP>1</SP> is advanced one tooth with a corresponding movement of the drum 300. Between such movements the diaphragm 326 is pressed inwardly whereby air pressure is transmitted to hollow spaces in resilient hammers 350 causing impact of the hammers against the metal sheet.