Patent GB-280176-A (GB)
Title: Improvement in levelling device for elevators
IPC: B66B1/44
Filed: 1927-10-08
Abstract: 280,176. Waygood-Otis, Ltd., (Assignees of Dunn, E. L.). Nov. 6, 1926, [Convention date]. Electric plant.-Mechanism for bringing a lift cage to a stop level with a floor comprises a member adapted to be moved at a lineal speed proportional to the speed of the cage which member co-operates with a rotatable member also driven at a speed proportional to that of the cage and thereby actuates switch mechanism. A belt 8, Fig. 1, secured to the top of the cage is wrapped spirally around a sheave 11 to which its end is attached. A similar belt 13 wrapped in the opposite direction around a sheave 20 extends parallel to the belt 8, but is passed round a tensioning sheave 15 at the bottom of the shaft and secured to the bottom of the cage. The sheaves 11, 20 are keyed to a shaft 21 which is connected by chain and sprocket gears to a shaft 43. This shaft is connected by bevel gears 49, 51 to a vertical screw shaft 52 upon which is threaded a crosshead 60 having bifurcated arms 64, 65, Fig. 3. An arm 71 is rotatably mounted in the bifurcated end of the arm 64 and carries a roller 81. A similar roller 88 is mounted in an arm 83 attached to the arm 65. These rollers are mounted so that they can be adjusted and are in different horizontal planes. They co-operate with a series of levelling cams 240 - - 244, Fig. 2, mounted on a shaft 230 which is driven by the shaft so that the distances between adjacent cams are in proportion to the distances between the floors. The upper and lower edges of the working face 252 of each cam are helices of the same pitch as the thread on the shaft 52. The bushings 68, 70 by which the arms 71, 83 are mounted in the arms 64, 65 are formed with square apertures 92, 93 through which pass switch operating rods 90, 91 of similar section. These rods are rotatably mounted in bearings on the baseplate 28 and extend loosely through apertures 98 in the top plate 30. The rods 90, 91 are of circular cross-section above the plate 30 and are journaled in bushed bearing apertures in the frame of a levelling magnet 104, Fig. 4. The rods 90, 91 also pass through apertures in the armatures 112, 113 of the magnet and are secured to them by pins 116, 117. Stop pins 118, 122 fixed to the armatures are arranged to engage stop shoulders 121, 124 on the frame 103. A swivel pin 127, Fig. 2, extends through apertures in lugs 125, 126 on the armature 112 and has a transverse aperture through which extends an eye-bolt 130. A similar bolt 136 is provided on the armature 113, and is connected to the bolt 130 by a tension spring 140. A fast speed levelling switch contact arm 141, Fig. 5, is pivoted on the rod 90 and carries a contact 142 that is adapted to engage a stationary contact 143 mounted on an insulating plate 144 attached to the plate 30. A compression spring 146 bears against a spring retainer on the arm and a seat 147 on the frame 103. A boss 150 extending from the arm 141 is engaged by an adjusting screw 151 threaded through the armature 112. An up slow speed levelling switch contact arm 153, Fig. 4, also is pivoted on the rod 90, and carries a contact 154 that engages a contact 155 on the plate 144. An insulating partition 161 separates the contacts 143, 155. A pin 194 mounted in the arm 153 extends through a slot 196 in a yoke 197 on one end of an interlocking bar 198. A yoke 203 on the other end receives a pin 206 secured to the armature 113. Spring 163 bears against a lug 165 on the frame 103 and the arm 153. An adjusting screw 166 is threaded through the armature 112 and bears against the arm 153. A fast speed levelling switch arm 168 of the same construction as the arm 141 is pivoted on the rod 91 which also carries a down slow speed levelling switch contact arm 183 of the same construction as the arm 153. A wiring diagram in the Specification shows the application of the apparatus to a variablevoltage cage switch controlled system, but the apparatus may be used in push button control systems and in systems using a motor supplied with direct or alternating current from mains. If the cage is at rest at the lowest floor 302, the magnet coil 106 is not energized, and the armatures 112, 113 are held against the stop shoulders by the spring 140. The screws 151, 166, 180 and 192 hold the levelling switch contact arms 141, 153, 168 and 183 so that their contacts are not in engagement with the contacts on the plates 144, 172. The spring 140 acts also through the armatures 112, 113, rods 90, 91 and levers 71, 83 to hold the rollers 81, 88 in their extended position. These rollers do not engage the cam 240 as it is positioned centrally with respect to them while the cage is at this floor When the cage is started, the actuation of the first accelerating switch causes the engagement of contacts, one pair of which completes the circuit for the coil 106, and the armatures 112, 113 are attracted. As the rods 90, 91 turn with the armatures, the rollers 81, 88 move away from the cam 240. At the same time the screws 151, 180 disengage from the fast speed levelling switch contact arms 141, 168, and these arms are turned by the springs 146, 175 to bring the contacts 142, 143 and 170, 171 into engagement. The turning of the armature 12 causes the screw 166 to disengage the arm 153, but the movement of this arm by the spring 163 to engage the contacts 154, 155 is prevented by the interlocking bar 198. Similarly the contacts 184, 185 are prevented from engaging by the bar 215. The up slow speed levelling switch contacts 154, 155 are in the circuit of the fast speed levelling switch contacts 142. 143, and the down slow speed levelling switch contacts 184, 185 are in the circuit of the fast speed levelling switch contacts 170, 171. The upward movement of the cage drives the shaft 21 and the shafts 43, 52 of the levelling machine are rotated. The crosshead 60 moves upwards. If the attendant centres the cage switch to stop at the next floor, the coil 106 will become de-energized, and the spring 140 will turn the armatures 112, 113 until they are stopped by the engagement of the pins 118, 122 with the shoulders 121, 124. The movement of the armatures causes the screws 151, 180 to turn the fast speed levelling switch contact arms 141, 168 against the springs 146, 175, so that the contacts 141, 170 are separated from the contacts 143, 171. The rods 90, 91 turn with the armatures and cause the rollers 81, 88 to be extended for engagement with the cam 241. If the cage has under-run the floor, but the end portion 255 of the face 252 of the cam 241 has struck the roller 81, the continued movement of the cam will have caused the roller to ride up the cam and move outwardly from the cam shaft. This movement turns the rod 90, and the armature 112 turns counter-clockwise, Fig. 4. Springs 163, 146 cause the arms 153, 141 to turn with the armature 112, and the contacts 154, 155 engage, thereby completing a circuit for the up levelling direction switch actuating coil and the levelling brake and field switch actuating coil. Further movement of the armature 112 and arm 141 causes the contacts 142, 143 to engage and complete the circuit for the fast speed levelling relay actuating coil. The hoisting motor then runs at a suitable fast levelling speed. As. the cage nears the floor, the roller 81 rides on to the end portion 254 of the cam, and causes the separation of the contacts 142, 143, de-energization of the fastspeed levelling relay coil, and the lowering of the generator e.m.f. The hoisting motor then runs at its slow levelling speed. Shortly before the cage reaches the exact level of the floor, the roller 81 rides off the end portion 254 of the cam, thereby separating the contacts 154, 155, and causing the application of the brake and the disconnection of the generator from the mains. The cage is slowed down and stopped level with the floor. If the cage over-runs, it is brought back in a similar manner.