Patent GB-1015944-A (GB)
Title: Change speed transmission
IPC: F16H61/02
Filed: 1964-02-25
Abstract: 1,015,944. Change speed control. KEARNEY & TRECKER CORPORATION. Feb. 25, 1964, No. 7784/64. Heading F2D. In an electro-hydraulic control for a machine tool gear wherein a two-speed motor 5 drives an output spindle 3 through a main clutch 16, forward-reverse clutches 24, 25 and a sixteen speed sliding wheel gear 31 ... 47, a single control selectively alternates the motor speed and shifts the gear ratios to provide thirty-two ratios substantially in geometric progression. Gear arrangement.-The main clutch 16 is an hydraulically operated friction clutch and connects a motor driven input shaft 12 to an intermediate shaft 19 which carries the input elements of the hydraulically operated friction forward-reverse clutches 24, 25, the output elements of which are fast with forward-reverse bevel wheels 21, 22 meshing a bevel pinion 23 on a first shaft 31 of the sliding wheel gear. An additional hydraulically operated friction clutch 84 connects the input shaft 12 through a reduction gear 88 to the bevel wheel 22 to provide a creep speed input to the gear for facilitating ratio shift. The sliding wheel gear comprises four gear pairs A1, B1, C1, D1 axially slidable on shafts 31, 38, 45 to selectively mesh gears 33, 34, 39, 42, 43, 44 fixed on shafts 35, 40. Spindle braking is provided by simultaneous engagement of both the forward and reverse clutches 24, 25 effected only after the main clutch 16 has been disengaged. Fluid-pressure system.-The system is supplied by a pump P, Fig. 9, drawing from a reservoir 60. The four sliding gear pairs are operated by two position differential pistons A, B, C, D which are moved right by supplying pressure liquid selectively through solenoidoperated valves 160, 161, 162, 163 to their left faces in opposition to pressure supplied through a line 57 which acts on their smaller right-hand faces and moves. them left in the absence of rightward selector pressure. The selector valves 160, 161, 162, 163 are biased left by springs to connect the left faces of the pistons A ... D to a vent line 67 and are moved right against the spring bias on energization their solenoids to connect the left faces of the pistons to a main pressure line 61. The main clutch 16 is supplied with pressure liquid through lines 69, 71 and a solenoid-operated valve 164. A branch line 73 normally supplies pressure liquid to a forwardreverse spring centred solenoid-operated selector valve 72. Energization of solenoids E, F respectively move the spool of valve 72 left or right to supply pressure liquid to the reverse or forward clutches 25, 24. On de-energization of the solenoid G the valve spool is moved left by a spring to vent the main clutch 16 through lines 75, 67 and pressure liquid is supplied from the line 71 to line 74 and through the centred valve 72 to engage both clutches 24, 25 for spindle braking. The larger end of each piston A ... D has two grooves 58, 59 one or the other of which is aligned with ducts 76 ... 80 when the pistons are in their extreme positions to provide a pressure fluid line to the right end of a valve 70. This pressure moves the valve spool to the position shown. If during ratio shift the gears do not mesh precisely one or more of the pistons A ... D will fail to complete its movement and thus block the pressure line to the right end of the valve 70 whereupon a spring 70<SP>1</SP> moves the valve spool right to vent the line 71 thus releasing the clutches 24, 25 and to supply pressure liquid to the creep clutch 84 so that the gears are rotated slowly to permit completion of the shaft movement. Completion of the shift restores the supply of pressure fluid to the right of valve 70 thus disengaging the creep clutch 84 and reconnecting the line 71 to the pressure source. Electrical system.-Closure of a switch 103, Fig. 10, energizes a relay 105 which in turn closes a switch 97 to start a motor PM driving the pump P and also closes a holding switch 106. The motor PM may be stopped by opening a normally closed switch 104. The main clutch is engaged by closing an on-off switch 124 which energizes a relay 123 to close a switch 122 and complete the circuit to the clutch solenoid G. Closure of a three-position forward-reverse switch 125 selectively energizes relays CW-R, CCW-R which close switches 127, 126 in the circuits to the operating solenoids F, E of the forward-reverse valve 72. Ratio shifts are initiated by movement of a manually controlled contact arm 118 which moves over a contact panel and connects contacts 119 selectively to contacts 113, 121, 130, 132, 128, 134 to complete the circuits to relays 107, 120, AR, BR, CR, DR which respectively close switches 98, 99 for high and low motor speeds and close switches 131, 133, 129, 135 to energize shift valve solenoids AC, BC, CC, DC. During ratio shift a switch 155 is opened to de-energize the main and forward-reverse clutch solenoids G, E, F whereupon both clutches 24, 25 are engaged for spindle braking. Manual control switch.-The contact arm 118, Fig. 6, is fast with a shaft 137 freely rotatable in a housing 140 which carries the contact panel 146. A control knob 138 and dial 145 are fast with the shaft 137 and a pointer 142 on the housing co-operates with dial to indicate the output speed selected. The shaft 137 is held in the selected position by projections 145a on the disc engaging recesses 145b in the housing. For ratio shift the knob 138 and shaft 137 are moved axially left against the bias of a spring 137a to release the projections 145a from the recesses 145b and thereafter rotated to select a new ratio.