Patent GB-190513709-A (GB)
Title: Improvements in Systems of Motor Control
Inventor: CASE FRANK EDWIN
Filed: 1905-07-03
Granted: 1906-05-31
Abstract: 13,709. Case, F. E. July 2, 1904, [date applied for under Patents Act, 1901]. Switches. - Relates to improvements upon the type of motor control system described in Specification No. 10,135, A.D. 1899, in which a mastercontroller acts through controllers of the separatelyactuated contact type and the handle is connected to the cylinder through a flexible connexion, such as a spring. In the present arrangement, the rate of acceleration is automatically controlled and the amount of current input gradually increased, a checking- device controlled by the current in the motor circuit being arranged in connexion with the speed-limiting device of the controller. A latch is also provided for holding the handle in any desired position. Fig. 1 shows the general arrangement, in which 45 is the circuit-breaker for opening circuit should the handle be released, 60, 61 are the starting-switches, the switch 61 being closed momentarily only, B is the main circuitbreaker, which is closed when the switch 61 is closed but opens with an overload, and 70 is a throttle for checking the rotation of the master-controller and preventing the resistances from being cut out too rapidly. Means are provided for rendering this relay inoperative. The master-controller is shown in Fig. 2. The cylinder 76 is rotated by a handle 77, the arm 78 of which is integral with a sleeve 78<a> keyed on a shaft 79. The other arm 77<a> is fixed to a sleeve 81. The flexible connexion or spring 105 is mounted on a drum fixed to a sleeve 82<a> on the shaft 79. On the sleeve is a wheel 82 gearing with a wheel 83 keyed on the shaft 84, which carries the cylinder 76 and also a collar 76<b>, Fig. 6, which contains the mechanism which connects the cylinder to the speed-limiting device, Figs. 5 and 6. A ratchet-wheel 97, Fig. 7, is loosely mounted on the shaft 84, and carries a spur-wheel 85 engaging a pinion 86 loosely mounted on a shaft 87, Fig. 6. Fixed to the pinion 86 is a wheel 88 gearing with a pinion 89 mounted on a sleeve carrying at its upper end a sleeve 90 having radial arms 91 to which are pivoted the centrifugal friction arms 92, Fig. 5, adapted to engage the cylindrical shell 94. The weighted arms and shell are made of magnetic material, and a coil 96 is enclosed in the shell and acts, when energized, to cause the arms to engage the walls tightly and form the checking-device K, Fig. 1, which is connected to the relay 70. This may be rendered inoperative by mechanism including a ratchetwheel 97, Fig. 7, and pawls 99 pivoted upon arms 98. When it is desired to operate the controller without the limiting-device, the pawls are moved out of engagement with the ratchet-wheel by a cam-plate 100 operated by a handle 101. The actuating-spring 105, Figs. 2 and 9, can be cut out by means of a pin 107, which, when depressed, locks the upper and lower ends of the drum together so that the cylinder is directly operated by the handle. The pin is normally raised. The spring drum is provided with notches engaged by a hook on the spring, so that the tension of the spring can be adjusted. The turning movement of the spring in the cylinder may be made constant by mounting the shaft 79 out of line with the shaft carrying the wheel 82, and working in a cam-groove in the drum 104. In the upper part of the controller casing is placed the auxiliary cutout switch and emergency-brake controlling device. A sleeve 113, Fig. 3, is fitted on the spindle 79, and is locked to it when the knob 119 is depressed. On this sleeve is a cam 123 engaging an arm 124. When the knob is released, a spring returns the sleeve, and an arm 128 operates a brake-controlling valve 129. The arm may be held from operating, the brakes by moving the reversing-switch into its mid or ' off' position, a link 133 being provided with a lug engaging a projection 135 on the sleeve 113. The interlock between the reversing-switch and the shaft 79 consists of a rocking lever which engages a cam in the reversing-switch shaft and also in a notch in the upper head 106, Fig. 9, of the drum 104. The operating-handle 77 is provided with means for locking it in any position. The arm 77<a> is integral with a sleeve 81, which has a limited movement relative to the arm 78 which is keyed to the shaft 79, the-bolt 115 sliding in a keyway. A lug on the bolt engages a lever 121 which engages a lever 120. To hold the handle at any point, a latch 145, Fig. 12, pivoted to the arm 78 is arranged to engage notches 148 in the top of the casing. When the handle is moved backwards, a plate 150 engages a projection on the latch, and raises it out of the notches. Fig. 14 shows a modified arrangement of throttle 70 for allowing an automatic increase of the current taken as the acceleration proceeds. An additional coil 71<a> is provided in shunt to certain of the resistance sections.