Patent GB-402859-A (GB)
Title: Improvements in and relating to power transmission systems
IPC: F16D23/02
Filed: 1932-06-17
Abstract: 402,859. Clutches ; variable-speed gearing. FRANK, B., 6, Sim de Ruyterlaan, Bandoeng, Java, Dutch East Indies. June 17, 1932, No. 17238. [Class 80 (ii).] A clutch for connecting a driving shaft 8 to a shaft 36 comprises a liquid-filled cylinder 9 secured to the shaft 8 and having journalled therein a hollow shaft 16 within which is splined a shaft 17 which is urged to the left by a spring 12 into contact with a socket 29 encircling the shaft 36, the adjacent ends of the shafts 17, 36 having dogs 24, 25, the adjacent ends of the shaft 16 and socket 29 having dogs 21, 22, and the socket 29 having internal dogs 33 engaged by bevelled dogs 32 on a spring- pressed sleeve 34 splined on the shaft 36. Planet gears 54 mounted in a carrier 26 are each of two diameters 53, 55 meshing respectively with teeth 27 on the neck of the cylinder 9 and with teeth 31 on the socket 29, the pitch circle of the teeth 27 being of greater diameter than that of the teeth 31. A male thread 28 on the socket 29 co-operates with a female thread in the neck of the cylinder. In the form shown in Fig. 1, a sleeve 11 splined on the shaft 16 and formed with a male thread is integral with a piston 4, the thread co-operating with a spring-pressed nut 15 splined in the cylinder 9 so as to have a small amount of axial play. In the form shown in Fig. 3, the piston 4 has a female thread co-operating with a male thread on the shaft 16 and has projections 204 engaging grooves 210 in the cylinder, The grooves 210 may be axial, in which case the piston is urged to the left by a spring ; or they may be formed along a helix having a pitch exceeding and opposite to that of the thread of the shaft 16, in which case the piston automatically tends to move to the left. In both forms, the cylinder has internal grooves 10 which taper off towards the left, and the piston has passages 5 therethrough controlled by a disc valve 3. Normally, the shafts 8, 36 are connected, with the piston in its extreme left-hand position and the gears 27, 31, 54 rotating solidly. To disconnect, the carrier 26 is arrested, so that the socket 29 will move the shaft 17 to the right, separating the dogs 24, 25 and finally engaging the dogs 21, 22. The piston 4 will thus move to the right until the threads disengage. To restore the connection, the carrier is released, whereby the socket screws back into the cylinder neck, the dogs 21, 22 disengage, the dogs 24, 25 engage, and the piston 4 returns to the left. During this piston movement, the valve 3 closes the passages 5 and the passage of liquid through the grooves 10 is gradually restricted, whereby the drive is taken up smoothly. If the shaft 36 over-runs the shaft 8, disconnection results. If it is desired to use the shaft 8 as a brake for the over-running shaft 36, the carrier is arrested, the shaft 36 then driving shaft 8 through the dogs 32, 33 and gears 31, 54, 27. In the form shown in Fig. 1, an armature 72 splined on the carrier 26 co-operates with an electro-magnet 71 so as to be arrested or released by depressing or releasing a spring-loaded contact button 101. In the form shown in Fig. 3, a ring 30 rotatable freely between the two parts of the carrier 26 has internal teeth meshing with the planet teeth 55 and an external thread which is of opposite hand to that of shaft 16 and which co-operates with ahalf-nut 52 slidably mounted on rods 38, on which is also slidably mounted a block 45 urged to the left by springs 39, a spring 51 being arranged between the members 45, 52. A spring-loaded latch 46 normally maintains the block 45 in the position shown and is adapted to be lifted by a spring-loaded latch 47. On depressing a lever 41, arms 49 raise the latch 47 and thus the latch 46, and the springs 39 move the block 45 to the left, whereby teeth 44 on the carrier engage a stop tooth 43 mounted to slide against a spring on a cross shaft 40 in the block 45. When the lever 41 is released, the latch 47 depresses the arms 49 so that a roller 50 carried thereby presses the nut 52 into engagement with the revolving ring 30, whereby the nut is screwed to the right and causes the block 45 also to move to the right, allowing latch 46 to fall and disengaging the teeth 43, 44. The nut 52 then returns to the normal position shown. During the movement of the block 45 to the right, a roller 48 carried by the arms 49 rides up an incline 45a to move the lever back to normal position. The clutch is shown combined with a four-speed and reverse gear wherein clutch rings 88, 91, 93 splined on the final driven shaft 86 are moved by slidable rods 79, 81, 84, the input gear 87 being secured to the shaft 36. As shown in Fig. 1, the rods 79, 81, which each control two forward speeds, each have pivoted thereto a pair of spring-loaded pawls 78, while the rod 84 which controls the reverse speed has only one pawl 78. Each pawl has two projections 75, 76 which co-operate with cross rods 59, 60, the rod 60 being carried by a ring 57 rotatable around but movable axially with the socket 29 while the rod 59 is carried by arms 62 pivoted to the ring 57 at 61 and to the casing at 63, whereby as the socket moves to the right or left the rods approach or recede from each other respectively. The pawls are adapted to be selectively depressed by the cores 73 of solenoids 74 controlled by a handle 103 provided with two contact members 106 and 107 which co-operate respectively with contact plates 108 and 109. After each gear change, the handle 103 is moved into a neutral position in which the members 106 and 107 are both out of contact with their respective plates. Assuming the handle to be in the neutral position 103<1>, after first speed has been engaged, and it is desired to change to second speed, the handle is turned clockwise to the position 103<2>. Thus the member 107 first contacts with the plate 109a<11>, thereby depressing pawl 78a. Then the member 106 contacts with the plate 108b, thereby energising the magnet 71 and disengaging the shafts 8, 36. During this disengagement, the rod 60 acts on projection 75 of pawl 78a to move rod 81 into neutral position. Then member 107 leaves the plate 109a<11>, causing pawl 78a to be released, and afterwards comes into contact with plate 109 b<1> so as to depress pawl 78b. The member 106 then leaves plate 108b, causing the shafts to re-engage, during which the rod 59, in moving to the right, acts on projection 76 of pawl 78b to move rod 81 to the right to engage second speed. The handle is then moved to the neutral position 103<2> to release the pawl 78b. In the form shown in Fig. 3, each of the rods 79, 81 has three pawls 77a, 77f, 77b, while the rod 84 has only two pawls, each pawl having a single projection. The pawls are adapted to be selectively depressed by cams 67a .... on a shaft 67 geared to a handle 69. Assuming that first speed is engaged and it is desired to change to second speed, shaft 67 is turned anti-clockwise to release pawl 77a and depress pawl 77f. As pawl 77f is depressed by its cam, a complementary cam acts to lift a pivoted arm 66, whereby a cross rod 64 acts on a projection 65 on the latch 47 to raise the latter and thus cause disengagement of the shafts 8, 36. Thus rod 60, in moving to the right, acts on the projection 75 of the pawl 77f to move the rod 81 into neutral position. Upon further movement of the shaft 67, pawl 77f is released and pawl 77b depressed. The connection between shafts 8, 36 is therefore re-established and the rod 59, in moving to the right, acts on the projection 76 of pawl 77b to move the rod 81 to the right to engage second speed.