GB335029A - Improvements in and relating to change-speed gears for radialarm drilling machines - Google Patents

Abstract

335,029. Heide, H. C., (Cincinnati Bickford Tool Co.). Aug. 23, 1929. Drilling - machines. -In a radial-arm drilling - machine the drill-head incorporates change speed gearing consisting of three sets of gears arranged on four shafts, the ;first giving a choice of four speeds of small ratio and the second a choice of two speeds of larger ratio and the third a choice of four other speeds of still larger ratio. In the example given, the first set of gears gives ratios of 1 to 0.9, 1 to 1, 1 to 1.12 and 1 to 1.25 (in a geometrical progression of ratio 1.12), the second gives ratios of 1 to 0.643 and 1 to 1, and the third ratios of 1 to 0.094, 1 to 0.226, 1 to 0.548 and 1 to 1.32 (in a geometrical progression of ratio 2.4) thus giving a total range of 32 speeds and a total ratio of from 1 to 0.05 to 1 to 1.65. The horizontal shaft P, journaled on the radial arm is driven at a constant speed and rotates the first shaft a, Fig. 1, through a clutch and one of a pair of oppositely rotating bevel gears 2, Fig. 2. The bevel gears are loose on a sleeve 1 keyed to the shaft and are clutched thereto by friction bands 25 expanded by levers 29 between drums 21 fixed to the gears and bosses 24 keyed to the sleeve by the keys 23 which key the sleeve to the shaft. The levers 29 carry abutment screws 33, locked in adjusted position by screws and plates 36, and actuated to engage either clutch by a sliding plate 30 having bevelled ends 32 and actuated by a bowl 35 and a hand lever (not shown). The first shaft a, Fig. 1, carries sliding gears A - - D, adapted to engage selectively with gears A<1>- - D<1> on a second shaft b, giving four speed changes. A two-speed connection is provided between shafts b, c, by gears E, F and El, F<1>, and a four speed connection from the shaft c to the drill-spindle e by gears G, G<1> or I<1>, I and a clutch K splined to the spindle or gears G, G<1>, I, I<1>, shaft d, pinion J and gear J' splined to the spindle or by clutch H, H<1>, shaft d and gears J, J<1>. In an alternative drive from the shaft c to the spindle, the pinion J, Fig. 3, and gear J<1> always remain in mesh and the latter carries clutch teeth 20 adapted to engage teeth 19 on a slidable clutch member 17 which also carries teeth 18 engageable with the gear I. The gears J', I are then loose on the spindle and the clutch 17 is splined thereto.