Patent GB-490338-A (GB)
Title: Change-speed and reversing driving mechanism suitable for machine tools
IPC: B23Q5/14
Filed: 1937-11-29
Abstract: 490,338. Change-speed gearing for lathes. COTAL, J. Nov. 29, 1937, No. 32895. Convention date, Nov. 30, 1936. [Class 83 (iii)] [Also in Group XXIV] An electrically controlled speed-changing and reversing mechanism comprises a number of planetary trains arranged in series between a driving shaft 1 and an intermediate driven shaft 2 and another mechanically controlled train between the shaft 2 and a final driven shaft 3. Each of the planetary trains comprises a sun wheel, an annulus and a planet carrier with one or more planet pinions. One of the elements of each train carries an armature 17, 18, 19 or 20 which co-operates with either a fixed electromagnet 9, 10, 11 or 12 to hold it stationary or an electromagnet 13, 14, 15 or 16 carried by another member of the same train so that the train can be locked solid. In the first planetary set, which serves purely as a reversing train, the annulus is secured to the driving shaft 1, the sun is connected to a sleeve 21 which is rotatably mounted on the intermediate shaft 2 and which also carries the electromagnet 13, and the planet carrier is free but integral with the armature 17 so that the train is either locked solid by energizing the electromagnet 13 for a forward drive or the carrier is held stationary for a reverse drive. The sleeve 21 drives the sun 26 of the next planetary set, the annulus of which carries the armature 18 and the planet carrier drives the annulus 30 of the next set. The sun of this set carries the armature 19 and the carrier drives the annulus 33 of a last electrically controlled set, the sun of which carries the armature 20 and the carrier of which is connected to the intermediate shaft 2. The planets of this last set are stepped. The intermediate shaft carries the sun 37 of the mechanically controlled train, stepped planets of which are carried by the driven shaft 3 and the annulus of which is adapted to be held stationary or locked to the sun 37 by clutch pins 32 carried by a sliding sleeve 40. By holding the armature of each of the last three electrically controlled trains or locking it to another member of the train each train either effects a speedreduction or drives direct. Similarly the mechanically controlled train can also provide a speed-reduction, or be locked solid, or rendered neutral, so that with the reversing train sixteen speed can be obtained in either direction by a combination of electrical and mechanical control. Switches 45 and 46 are provided for effecting the electrical control, the switch 45 for controlling the forward or reverse train and the switch 46 for the other speedchanging trains. The switch 45 is also adapted in one position to energize both of the electromagnets in the last of the electrically controlled trains which has a double armature 20, 20a so that a braking effect on the shafts 2 and 3 is obtained. This speed-changing mechanism is particularly suitable for use on lathes or other machine tools and the toothed wheel 62 on the driven shaft 3 may drive various auxiliary mechanisms such as feed-changing mechanism. A similar but smaller speed-changing mechanism to the one described may be employed for this purpose. In this case the action of the control switches for the two mechanisms may be synchronized with the control of the pivoting movements of the turrets or tool supports to provide for the proper rate of rotation and feed for the next operation. Further speeds may be provided by combining another speed-reducing device with the last mechanically controlled train.