GB585631A - Improvements in or relating to change-speed gearing for automatic lathes - Google Patents

Abstract

585,631. Change-speed gearing. TAREX SOC. ANON. July 3, 1944, No. 12630. Convention date, July 23, 1943. [Class 80 (ii)] A change-speed drive for the single spindle 15 of an automatic lathe comprises parallel driving and driven shafts 14, 15, carrying constant-mesh gear-trains introduced singly or compound by one or more double friction-clutches 16, 18 on each shaft, each clutch comprising a slidablykeyed double inner member 16, 18, between freely-mounted members, one, e.g., 17a, of each of which is secured to a compound wheel, the gear-wheels 30, 31, of which mesh respectively with wheels 33, 34 secured to the freely-mounted members 18a, 19a of the double clutch on the other shaft. Similarly the freely-mounted clutchmember 18a on the shaft 15 has a compound wheel, the teeth 32, 33 of which mesh with wheels 28, 30 secured to the freely-mounted members 16a, 17a of the double-clutch on the shaft 14. Combinations using three meshing wheel-pairs in series are thereby possible. An additional train includes a wheel 29 on the driving shaft 14 meshing with a wheel 35 integral with the freely-mounted wheel 34, a one-way roller clutch 20 being provided in the hub of the wheel 29 or 35. The clutch 18 is used in its two engaged positions only, that 16 being used also in a neutral position to give six ratios in ascending order as follows: (1) one-way clutch 20, wheels 29, 35 and clutch 18, 19a, the double clutch 16 being in neutral ; (2) clutch 16, 17a, wheels 31, 34 and clutch 19a, 18; (3) clutch 16, 16a, wheels 28, 32, 33, 30, 31, 34 and clutch 19a, 18; (4) one-way clutch 20, wheels 29, 35, 34, 31, 30, 33 and clutch 18a, 18; (5) clutch 16, 17a, wheels 30, 33 and clutch 18a, 18; (6) clutch 16, 16a, wheels 28, 32 and clutch 18a, 18. In combinations (2), (3) and (5) the one-way clutch 20 overruns. The gear is motor-driven through the usual pick-off gears and is controlled automatically by the usual cam mechanism. The Specification as open to inspection under Sect. 91 states also that, in order to avoid the necessity for a neutral position of the clutch 16, one-way clutches may be included in the wheels 28, 32, 33, the latter pair 32, 33 being made separate. A modification (Figs. 10-14 (Cancelled) and not shown) is also described, providing four speeds with no neutral position of the double clutches, the wheel-pair 29, 30 and one-way clutch 20 being omitted and a stepped idler interposed between the wheels 31, 34 so that the two low-speeds are in the opposite direction to the two high. The stepped idler is exchangeable to vary the range of ratios, and may also be similarly introduced into the form shown in Fig. 2. A modification of this form provides only three ratios by making the wheel 31 separate from the wheel 30 and securing it directly to the driving shaft 14. This subjectmatter does not appear in the Specification as accepted.