Patent GB-337106-A (GB)
Title: Improvements in and relating to change speed gearing for drilling and boring and comparable machines
IPC: B23B47/14
Filed: 1929-08-23
Abstract: 337,106. Cincinnati Bickford Tool Co., and Klausmeyer, D. C. Aug. 23, 1929. Drilling - machines; driving machines.-A drilling' or similar machine such as a reaming, tapping, facing, milling, lapping or turning machine, has a gear-box giving a range of thirty-six speeds controlled by four levers arranged adjacently on the drillhead, the first two levers giving three speeds each and the others two speeds each. The levers are connected with indicators which, in conjunction with a chart, indicate the correct spindle speed for any size of drill within the range of the machine. As applied to a radial-arm drilling-machine the power shaft P, Fig. 2, journaled on the radialarm drives a gear shaft 1 in one direction or the other through one of a pair of bevel gears 7. The shaft 1 has splined thereto the gears a, b, and carries rotatably a gear f combined with a clutch e. The drive is transmitted to a second shaft 2 through (1), gears a, c, or (2) b, d, or (3) through clutch b, e and gears f, g. A third shaft 3 is driven from the shaft 2 through (1), gears h, i, or (2), c, j, or (3), through clutch j<1>, l<1> and gears k, l, while the drill spindle s is driven from the shaft 3 through (1), gears m, n and clutch v, o, or (2), gears m, n, gears o, p, q, r and clutch s, t, or (3), clutch x, w, gears q, r and clutch s, t, or (4), through clutch x, w gears p, o, and clutch v, o. The gears a, b are moved axially to their three positions by means of a hand lever 30 carry-. ing a toothed segment 32 engaging a rack-bar 34 which rotates a shaft 37. A lever 38 on the shaft 37 carries a yoke 39 engaging an annular groove 40 in the gears. The gears i, j are moved to their three positions by a lever 46 carrying toothed segment 47 engaging a rack-bar 49 which oscillates a shaft 52 connected to the gears by an arm and yoke 53. The gears m, ware moved to their two positions by a yoke-arm 60 and a rack-bar 63 operated by a lever 65 and the clutch t, v, is moved to its two positions by a yoke-arm 74, a rack-bar 71 and a hand-lever 68. Each of thefour controls is provided with a notched segment such as 41 co-operating with a spring index plunger for maintaining the gears in the adjusted positions. The rack-bars 34, 49 carry indicators I. H. Fig. 3, respectively, co-operating with a. chart X, Figs. 3 and 6, consisting of four vertical columns of nine spaces in each column.. Each space is inscribed with a number representing a spindle speed and a number representing in inches the corresponding size of the hole to be drilled or bored. The indicator H overlaps the chart at h<1> and h<2> but has a gap 78 which exposes the ends of three adjacent horizontal rows whilst the indicator I is provided with three pointers i<1>, i<2>, i<3>, so spaced that in each position of the indicator H, one pointer will be exposed by the gap 78. To set the spindle speed for drilling a 1¢in. hole, the lever 46 is moved so that the gap 78 is opposite the three rows P<2>, Fig. 6, the lowest of which includes the size of drill required. The lever 30 is then actuated to position the pointer, i<2>, which is now exposed by the gap 78, opposite the row containing the 1¢in. indication, and the levers 65, 68 are moved up or down asindicated by the arms y, z, at the top of the column containing the size required. For an 1¢in. drill, the lever on the left (68) is moved upwards and the lever 65 downwards. For drilling holes of sizes from #in. to 4in. diameter the gears are arranged to give a peripheral speed of the drill of eighty feet per minute whilst for boring holes of sizes from 2“in. to 10in. diameter the peripheral speed of the tool is forty feet per minute. The settings for producing the higher cutting speed are represented by white indications in Fig. 6 and those for the lower cutting speed by coloured or shaded indications.