Patent GB-328567-A (GB)
Title: Improvements in or relating to the driving of metal drilling machines
IPC: B23Q5/14
Filed: 1929-01-29
Abstract: 328,567. Swift & Sons, Ltd., G., and Carter, J. Jan. 29, 1929. Drilling; tapping.-In a drilling-machine an indicator plate is provided bearing indicatons of the sizes of drills to be used in given materials for which the machine is designed and a selector is adapted to swing or slide so as to co-operate with the indications in order to operate a change speed gear and cause the drill-spindle to be rotated at a speed appropriate to the size of drill being used. The plate 1, Fig. 1, is provided with twelve holes 2 arranged in four rows a - - - with three holes in each row. The selector is an arm 3 carrying an index pin 3<1> for co-operation with the holes 2 and slidable within a housing 4 which is rotatable about the axis of a sleeve 5 attached to the housing and loosely supported on a coaxial shaft 6. The sleeve 5 and shaft 6 are connected to mechanism for producing twelve speed changes and independent means are provided for doubling this range to produce twenty-four speeds in one direction or twelve in one and twelve in the reverse direction. A hand lever 10, rotatable on the housing about an axis 9', carries a toothed quadrant 8 engaging a rack 3<3> on the arm 3 to cause the pin 3<1> to be displaced along the rows a, &c. A second rack 3<2> in the arm engages a pinion 7 on the end of the shaft 6, which is thus rotated by endwise movement of the arm, and rotation of the housing 4 and sleeve 5 from one row to another is performed by actuating the lever 10 in a different plane. The change speed gear, whose development is shown in Fig. 4, comprises a driven shaft 11, an intermediate shaft 18, a clutch shaft 28 and a gear wheel 39 splined to the drill-spindle 38. A gear 12 on the shaft 11 rotates the shaft 28 through a gear 29, and either of two gears 36, 37 may be clutched by a friction clutch 33 to the shaft 28 in order to drive a sleeve 15, loose on the shaft 11, at one of two speeds. Four pinions 15<1>, 15<2>, 15<3> and 17 on the sleeve 15 are adapted to drive the intermediate shaft 18 at one of four speeds through gears 22, 23<2>, 24, and 27 and a clutch sleeve 23 which is slidably keyed to the shaft 18 and carries clutch surfaces 23<1>, 23<3> adapted to co-operate with clutch surfaces 22<1> and 25<1> on the gears 22, 25 respectively. A loose gear 21 on the shaft 18 is adapted to be slid over the teeth of a gear 19 keyed to the shaft and engages the gear 32 which drives the spindle 38. The gear 21 may be moved endwise into two other positions, in one of which it engages a long pinion 13 and the gear 32, the pinion 13 being connected to the wheel 14 whch is driven from the gear 19, and in the other of which it engages the pinion 13 whilst a gear 20 secured to it engages a gear 31 connected to the gear 32. The shaft 18 may thus be rotated at eight different speeds and this shaft is connected to the drill-spindle in three gear ratios, giving twenty-four spindle speeds. A reverse drive using twelve of the speeds, may be adapted by moving the gear 37 endwise to cause it to drive the shaft 18 and the sleeve 15 through a gear 26. The clutch sleeve 23 is moved endwise from the rotary sleeve 5 by means of a lever 43', Fig. 5, thereon which carries a pin 43 engaging a slot 421 in a vertically moving member 42 connected to the clutch. The gear wheels 20, 21 are moved endwise from the rotary shaft 6 by a pinion 44<3>, Fig. 7, thereon, engaging a rack 44<2> on a vertically movable member 44 which straddles the gear 21. The members 42, 44 are guided by vertical rods 42<c>, 44<c> and are balanced by weighted levers 42<b>, 44b. The friction clutch 33, Fig. 4, is operated by an independent lever 49, Fig. 5, connected by a link 50 to a lever 51 having a yoke 52 engaging the clutch. An arm 54 connected to the lever 51 operates a sliding bar 53 which passes through notches 42<a> in the members 42, 44 and is slotted vertically to allow the members to pass in one position only. It is thus impossible to actuate the lever 49 to engage the clutch 33 with either of the gears 36 or 37 unless the members 42, 44 are in such a position as to cause one or other of the gear trains to be fully in mesh and it is also impossible to actuate the members to change the gears unless the bar 53 is in the " open clutch " postion. The gear 37 is moved endwise to reverse the drive by means of a lever 45, Fig. 5, link 46 and hand operated lever 47. The lever 47 has a tail 47<3> lying in the path of a pin 48 on the lever 49 so that, when using the machine for tapping, the lever 49 cannot be moved past its neutral position (after the tap has completed its operation), to the quick-drive position until the lever 47 has been moved into its reverse position. A pin 47<5> on a lever 47<2> attached to the lever 47 determines the forward and reverse drive positions. The pin 48 may be withdrawn when drive in one direction only is required, to enable the full twenty-four speeds in this direction to be utilized. A pinion 40 on the drill spindle drives the feed gearing (not shown). The Provisional Specification states that the selector arm 3 may effect the gear changes by giving both rotary and sliding motion to a single shaft.