Patent GB-305899-A (GB)
Title: An improved screw cutting machine
IPC: B23G1/10
Filed: 1928-06-26
Abstract: 305,899. Arnold, J. F., June 26, 1928. Turning wood-screws; steady rests; tools and tool-holders ; lubricating cutting-tools and work. -In a screw machine particularly for making wood-screws, the blanks are supplied automatically to a number of rotary spindles each coacting with a threading and pointing tool actuated by cam and lever mechanism from a single driving- shaft so that all the blanks are cut simultaneously. The driving-shaft 1 drives through worm gearing 8 and bevel gearing 10 - - 12, the auxiliary shafts 4 - - 7. The shaft 1 may also be connected by means of a friction clutch 24 to a central pinion 25 which drives the four workspindles 32 - - 35, the clutch being operated automatically from the shaft 6 through a cam 26 and lever 27. The chucks 20 - - 23 each comprise pivoted jaw levers 40, 41 which are closed on to the blanks by sliding conical sleeves 42 actuated simultaneously from a cam 46 through a lever 45 and double fork 43. The blanks are supported against the pressure of the, tools by members 48 - - 50 which are connected in pairs w slides 51, 52 which move in spaced guideways 53 and are reciprocated in opposite directions by means of a cam 56 and lever mechanism 55, 58, 59, Fig. 3. In this way the supports are moved up to the blanks during the cutting operation and withdrawn during the insertion of fresh blanks. Opposite the chucks are mounted toolholders 60 - - 63 secured in blocks 64, 65 slidable against springs 78 in a frame 66. The base 68 of the frame is longitudinally movable in a guide 82. The tool-holders are moved laterally by two members 71, 72 mounted one at each end of the tool-head, these members having wedge parallel strips between which the blanks, held by their heads, descend to a position adjacent the portions coacting with rollers 73 - - 76 on the tool blocks. Vertical movement is imparted to the wedge members from a cam 81 through a lever 79, block 85, and cress bar 78. The longitudinal movement of the tool-holders is effected by means of a double-acting cam 83 and a lever 84 connected to the base 68. Each tool-holder is provided with a conduit 86 through which oil may be pumped on to the tools during operation. The tools are shaped as shown in Fig. 9 and in operation the tool is first moved up to the work so that the portion 60a performs the pointing operation and is then moved longitudinally for the part 60b to form the thread. A second or finisbing cut is then taken. The blank-feeding mechanism comprises a pair of receptacles each provided with inclined shoots 88, 89 comprising blank-holders 90, whence they are pushed into the chucks which are thereupon closed. The clutch 24 is then engaged to rotate the chucks while the tools are first moved longitudinally towards the chucks, then fed in laterally to shape the point and then longitudinally to finish the thread. A second cut is then taken, after which the chuck jaws open and allow the blanks to fall into a receptacle while, the clutch 24 is disengaged in readiness for another cycle of operations. In a modification, the tool blocks may be separated for the lateral movements of the tools by means of a pair of cams 105, 106, Fig. 5, operated by gearing 109 - - 111 from a lever 112. The machine may also be adapted to produce more than four screws simultaneously.