Patent GB-450833-A (GB)
Title: Improvements in or relating to metal-cutting and like machine tools
IPC: B23B9/02
Filed: 1934-10-22
Abstract: 450,833. Metal cutting machine - tools. GARRARD, C. G., Tunstall, Crossways, Shenfield, Essex. Oct. 22, 1934, No. 30190. [Classes 83 (ii) and 83 (iii)] A lathe or the like for producing repetition articles from bar stock comprises a carrier adapted to support a number of non-rotary bars of stock the carrier being given successive rotary indexing movements to present the bars successively to rotary tool means which form the articles and part them from the bars. An indexable and reciprocating work carrier 24 carries a number of work bars 25 spaced circumferentially there-around, twenty-four bars being used in the form shown. The work carrier is indexed by cams mounted in a casing 26 and arranged to perform one revolution at the end of the withdrawal movement of the carrier when the bars are clear of the tools. The locking pawl engages a notched ring provided with a vibrationresisting clamping-band 105 tensioned by a spring device 106, the clamping pressure being released by a cam during the indexing movement. As each stock bar passes the lowest position in its cycle a fresh length is fed forward to the tools. For this purpose a fixed cam 107 normally keeps toothed plungers 108 in gripping contact with the bars passing through carrier plate 110 but a depression in the lowest point of the cam allows the plungers to retract and the bar in this position is prevented from moving backwards by a pawl. Thus when the work carrier moves back this particular bar is held stationary so that it is relatively fed forward in the carrier. At the next indexing movement the bar is gripped in its advanced position by its plunger 108. The tools are all supported around a member 28 concentric with the carrier axis and having a number of flat surfaces 29 to which the tools are secured, nine (as shown) or other number being provided. A sliding mandrel 31 secured to the work carrier moves in the member 28 and coacts with a slide 32 in supporting and guiding the carrier. The mandrel is secured to a tool control member 34 which is flatted to correspond with the various tool stations and which carries a roller 35 engaging a cam 27 for reciprocating the work carrier. The tools are carried in various rotary headstocks which may be assembled as self-contained units and secured to the bed 28. In the case of tools requiring axial movement such movements are derived from the movement of the tool control member 34 while radial tool feeds may be produced from the member 34 through the use of wedge slides. Each headstock is provided with a pulley 43 driven through single belt 38 passing round idlers 41 from a motor 39, the belt also driving the pulley 40 which may drive the cam shaft through change-speed gearing 42 operated by cams on the main cam shaft. The main drive may also be conveyed through changespeed gearing associated with the motor 39 so that the maximum permissible cutting speed may be employed for all classes of work. A circulating pump for cutting fluid may also be driven from the motor. The cutting off tool may be associated with mechanism to increase the rotatory speed as the centre of the work is approached to give a constant cutting speed. In an example given for making castellated nuts from hot rolled bar, the nut is centred, faced and skimmed at station A castellated at positions B, C and D, drilled and formed at E further formed and recessed at F, and tapped, parted and ejected at G. The headstock at A is shown in Fig. 5 no radial or axial tool movement being required. As the bar 25 moves forward to the tool head it is turned by a tool 45, centred by tool 46, and faced by a tool 47. The castellating saw mounted at B, C and D is shown in Figs. 7 and 12. The cutter 48 is driven from the pulley 43 through gearing 51, 52 bevel gearing 53 and worm gearing 57 and is mounted on an inclined slide 58 operated by a non-rotary spindle 49 connected to the tool control member to move the cutter across and longitudinally in unison with the advancing work. The headstock at E for drilling and exterior shaping is shown in Figs. 13 and 14. This includes a drill 61 driven directly from the pulley 43 and connected through epicyclic gearing to a number of spindles 65 having both rotary movement and planetary movements round the work. The number of tools 66 and the number of blades therein and their speeds are chosen according to the number of facets to be formed on the work, the arrangement shown being for producing hexagonal nuts while square or octagonal nuts may be produced by two bladed or four bladed cutters respectively in a similar headstock. The headstock at F for forming and recessing the back end comprises tools 74, 73, Fig. 16 mounted in a rotary head 72 driven from the pulley 43a. A bar 71 connected to the tool control member moves the inclined tool slides 75, 76 at the same speed as the advancing work while the required radial movement is produced by the construction of the slides. The parting and tapping headstock at G, comprises a pair of parting tools 80, Fig. 19, which are moved axially with the work and also radially by means of a rotary sleeve 82 connected to the tool control member and operating the inclined slides 81. The lower tool shows the position at the end of the parting operation. A stationary sleeve 83 has at its forward end a hexagon socket 85 into which the nut 86 to be parted from the bar 25 enters against the resistance of a spring. The tapping spindle 88 passes through this sleeve and is geared to a shaft 89 connected to the main headstock spindle. The end of the tapping spindle is connected through a lever 91 to the reversing gear and through a link to a lever 95 operated by the main cam drum 96. When the work advances the nut enters the hexagon tube and pushes back the tap. This operates control rod 92 and causes the tap to rotate at the required speed and enter the nut which is about half penetrated when the nut is parted, the spring keeping the nut against the parting tools to trim up the back face. The main cam then moves lever 91 to move control lever 92 and increase the tap speed, drawing the nut away from the tools and completing the tapping. The work carrier now retires, cam 96 causes reversal of the tap rotation and withdrawal of the tap whereupon the nut is shot out of the tube by the spring into a receptacle. The variable-speed gearing for the tap comprises conical planet members 97 carrying pinions 99 having a pitch diameter corresponding to an intermediate section of the planets. The pinions gear with an annulus 100 connected to the tap spindle through the shaft 89 and the cage of the planet members is driven from the pulley 43. The planets roll on a flexible belt member 101 anchored to the speed control rod 92. In the position of the parts shown in Fig. 19, the tap is not rotated but by movement of the control rod as described above the drive of the tap is effected in one direction or the other.