Patent GB-306979-A (GB)
Title: Mechanical movement for controlling the actions of tools in metal-cutting machines and for controlling other actions of precision
IPC: B23B39/24
Filed: 1927-10-28
Abstract: 306,979. Metcalfe, T. Oct. 28, 1927. Combined turning, drilling, screwing, and slotting machines.-In a metal - cutting machinetool such as a vertical work turret lathe for the production of gear blanks, the tools, the worktable, and other moving parts are controlled by a number of mechanisms each arranged to impart intermittent rotary or reciprocatory movement at predetermined times to its respective machine member. In the machine shown the operations performed consist in (a) turning the end faces and the peripheral faces of the blank, (b) boring and if necessary tapping the central hole in the blank, and (c) slotting a key-way in the blank. The intermittent controlling mechanisms each comprise a continuously-driven wheel 5 which is integral with a wheel and is carried by a sleeve 8 loose on a shaft 7. The wheel 3 engages a loose wheel 4 which also engages a wheel 2 integral with a sleeve 6 carrying a cam disc 9. The wheel 3 has one tooth more or less than the wheel 2. The sleeve 8 terminates in a flange 10 carrying a pivoted pawl 11 which is pressed into engagement with the cam 9 by a spring 12 and which has a projection 11<c> adapted to engage the projection 13a on a hub 13 secured to the shaft 7 to which intermittent motion has to be imparted. Thus in operation, on account of the different tooth-numbers of the wheels 2, 3 the cam 9 rotates somewhat faster than the flange 10 and pawl 11, thus at one point, Fig. 1, allowing the pawl to drop on to the lower part of the cam 9. In this position the hub 13 and shaft 7 are driven with the sleeve 8 and this rotation continues until the pawl has moved through the arc y relatively to the cam whereupon the pawl is lifted by the rise 9<b> and rotation of the shaft 7 ceases until the position x is again reached. The direction of rotation may if necessary be reversed and in this case the flange 10 is arranged to rotate faster than the cam 9. In the application of the invention to a work turret lathe, four of these mechanisms x<1> - - x<4> are embodied, these being respectively arranged for feeding the tools to the work, withdrawing the tools, withdrawing and re-engaging the tablelocking bolt, and for controlling the indexing movement of the table. The base 30 is provided with an annular support 32 for the table 33, the hub of the table fitting over a central pillar 31. Peripheral teeth 33<d> on the table are. engaged by a pinion 34 mounted on a vertical shaft driven through bevel gearing 35 and spur gearing 35a from the shaft 7, the latter being operated by the mechanism x<4>. The ratio of this gearing is such that each period of rotation of the shaft 7 imparts the indexing movement of onesixth of a revolution to the table. The wheel 5 of this mechanism is operated from a main shaft 41 through gears 39, 40. The locking and unlocking of the table is performed by the mechanism x<3>. The locking bolt coacting with notches in the work turret is actuated by a cam 47<a> loose on the shaft 7 and driven intermittently from the hub 13 of the mechanism through bevel gearing 50, spur gears 49 and worm gearing 48, 47b, the gearing being so arranged that each period of movement of the member 13 comprising 64 revolutions imparts one revolution to the cam. The action is timed so that the locking bolt is held in its withdrawn position while the tableindexing movement is effected. The driving shaft 60 driven by a pulley 61 drives through spur gearing 62 - - 66, worm 68 and spur wheel 70, the wheels 71 which are loosely mounted on the spindles of the tables 74. The wheels 71 may be connected to the spindles by clutches 75 operated by levers coacting with cam surfaces 78 which are spaced around the table so as to disengage the clutches at stations where rotation of the tables is not required. The main shaft 41 has two speeds, the low speed being obtained from the shaft 60 through the spur gearing 62 . - 64 spiral gearing 80 worm gearing 83 and ratchet mechanism 86. The high speed is obtained from the shaft 60 through belt gearing 88 bevel gearing 91 - - 95 and loose sleeve 95<a> and friction clutch 96. The clutch is operated to give the high speed drive by means of a lever 102 and cam wheel 100 rotated through reduction gearing from the main shaft. The tools 103, 104, and 106 are mounted on vertical slides guided on the the pillar 31 and the rotary tools are driven from a pulley 170, bevel gearing 173, vertical shaft 174, and spur gears 177 - - 179. The slides 103a 106a are fed by means of a vertical rack bar 107 and toothed quadrants 103<b>, 106<b>, the bar 107 being operated by screw and nut mechanism 108. The horizontal tool slides 105<a> are also actuated from the wheel 108 through a horizontal shaft 110 which through bevel gearing, vertical shaft 144 and spiral gearing 146, actuates the left-hand tool slide, Fig. 5. The right-hand tool side is similarly operated through spiral gearing 112 and vertical shaft 149. The shaft 110 has an intermittent reversing drive in order to feed and withdraw the tools, and this drive is conveyed by the mechanisms x<1> and x<2>. During the working stroke of the tools the mechanism x<1> is operated from a wheel 40 mounted on the shaft 41 which, for part of this movement, while the tools are cutting, is driven at its low speed through the ratchet mechanism. For the return stroke, the shaft 110 is driven in the opposite direction by means of the mechanism x<2> which is operated from a gear 142 on the shaft 41. The vertical shaft 149 is extended to drive through bevel gearing 153 and 156 a screw by which a tap is fed into the work, the reversal of the shaft 110 serving to withdraw the tap from the work. When a reciprocating slotting tool 183 is required, its. support 180 fitted with a clapper 181 is mounted in place of the tap-holding slide and the shaft 155 carries an eccentric 182 which reciprocates the tool 183 against a spring 186. A projection on the shaft 155 actuates a star wheel 184 to shift a wedge member 185 to impart feed to the slotting tool, the reversal of the shaft 155 serving to return the slotting tool to its original position.