Patent GB-191126864-A (GB)
Title: Improvements in and relating to Starting and Speed Control Gear for use with Electric Motors.
Inventor: MASCORD GEORGE WILLIAM
IPC: H02K7/10
Filed: 1911-11-30
Granted: 1913-02-28
Abstract: 26,864. Mascord, G. W. Nov. 30. Driving printing-machines; stopping and starting arrangements.-In starting and speed gear for electrically-driven printing-machines where clutches are used for low and high speeds, electrically-operated means are provided for the simultaneous operation of the electric motor controller and of the low and high speed clutches. In the arrangement shown in Fig. 1, a clutch a is employed for the high-speed or direct drive. The end of its operating-lever a<1> rests in a cam-groove b<1> in a worm-wheel b engaged with a worm c. The worm-wheel is connected by chain d<2> and wheels d<1>, d<3> to the field controller d of the electric motor, so that the clutch a and controller d are operated together. The worm spindle is connected by gearing g, h to two soft-iron bosses f arranged on each side of an iron pulley e loosely mounted and rotated continuously from the motor spindle. The bosses f are also loosely mounted and carry coils connected to slip-rings. When one set of coils is energized, the pulley e is attracted to the boss carrying the coils, and the worm c is rotated to operate the high-speed clutch and the field controller. When the other set of coils is energized, the worm is rotated in the other direction. A brake strap i may be arranged to encircle one or both the bosses; it is normally held on by a spring but is drawn off by an electro-magnet when current is supplied. The low-speed clutch j, which transmits the motor drive through gearing, is operated by a solenoid k. The control is effected by a series of push buttons 2, 3, 4, 5, 6. The first is a ' stop ' button, and the next, 3, is the starting- button which completes the motor circuit through the armature resistance 27 and the automatic starter 28. The button 4 controls the circuit of the solenoid k which puts in the low speed clutch j. When the motor speed has risen sufficiently, the button 4 is released to take out the clutch j, and the button 5 is depressed to complete the circuit of the coils f on the left-hand boss. The pulley e is attracted and the worm c is rotated to put in the main clutch a and to rotate the controller d. As the controller rotates, the contact 16 finally short-circuits the armature resistance, and the contact 17 puts resistance into the field circuit. When the button 6 is depressed, the coils of the right-hand boss are connected in circuit, and the worm c is rotated to take out the clutch a and to bring the controller d back to its initial position. Depression of the button 2 completes the circuit of the trip coil 33 of the main switch. In a modification, electro-magnetic clutches are used, as shown in Fig. 6. The driving-shaft a carries flanges D<2>, D<3>, to which are attached the driving-members of the clutches. The clutches are similar in construction, and the actuating- coils of the low-speed clutch are disposed in the space between two concentric magnetic rings E<1>, E<2>, which form the driving member of the clutch. An air-gap is left between the outer ring E<2> and the yoke ring E<3>. The armature E<4> is carried on pins passing through a flange on the ring E<2>, and coiled springs on the pins press the armature away from the ring E<2> when no current is flowing. The driven member of the clutch is an annular plate E<5> between the rings E<1>, E<2> and the armature E<4>. It is secured to a sleeve G<1>, which carries the first pinion G of the slow gearing. The driven member F<5> of the high-speed clutch is secured to the shaft B. Current is supplied to the coils through slip-rings r and brushes r<1>. The toothed wheel J, by which the low-speed drive is transmitted to the shaft B, is secured to a sleeve J<1> on ball bearings. The sleeve J' has a number of recesses in its periphery which taper circumferentially and contain rollers s pressed towards the narrow ends of the recesses by springs. A disk L is keyed to the driven shaft B, and its periphery flange L<1> fits over the recesses in the sleeve J<1>. When the shaft B is driven through the slow gearing clutch, the disk L is locked to the toothed wheel J by the action of the rollers S, but when it is driven through the high-speed clutch, a free-wheel effect is obtained. Fig. 9 shows a hand controller and an automatic starter 9. When the starting-button 2 is pressed, the relay switch 30 is operated, and current then passes to the coil of the switch 8. The latter switch completes the circuit of the operating-coils of the starter 9 and the switch 10. This completes the motor circuit. As the controller is rotated, the contacts 26, 27 put in the low and high speed clutches respectively, the contact 28 shortcircuits the armature resistances, and the contact 29 introduces resistance into the field circuit. A lock - button 4 is connected in the circuit of the operating-coil of the starter, and emergency buttons 5, 35 are provided to control the no-volt circuit-breaker 12. The control may be effected without an automatic starter; or the controller may be operated by a pilot motor. In the latter case, a hand-wheel and clutch may also be attached.