Positional control
AssigneeDewhurst & Partner Limited
InventorGeorge Eric Minns
Life of this patent
Estimating the term…
Abstract
Control apparatus having particular application to the control of the deceleration of an elevator or lift car in approach of a stop position, the apparatus including a sense coil mounted on the lift car and a magnetic member mounted on the lift shaft to vary the flux through the sensing coil in a predetermined manner relative to the distance to go to the stop position, the deceleration being controlled in accordance with the voltage induced by the flux in the sense coil. A magnetically operated switch is also provided on the lift car to respond to the magnitude of the flux to provide a stop signal defining the stop position.
Claims12
Control apparatus for controlling the relative motion of first and second relatively movable members, said apparatus comprising:
- a. flux responsive means attached to one of said first and second members;
- b. magnetic means attached to the other of said first and second members for cooperation with said flux responsive means to change the flux therethrough on relative movement of said first and second members;
- c. means responsive to the rate of change of flux through said flux responsive means to provide a control signal in accordance therewith;
- and
- d. means for reducing the relative speed of said first and second members in response to increase in said control signal, whereby to tend to maintain the rate of change of flux through said flux responsive means at a constant level.
Elevator control apparatus for decelerating an electricmotor-driven elevator car as it approaches a given floor during its vertical travel relative to the elevator shaft and for braking the car when it reaches the floor stop position, comprising
- a. a pair of vertically spaced flux sensing means (12, 14) adapted for connection with one of the car and shaft members, each of said sensing means including
- 1. a body member having a generally U-shaped crosssectional configuration defining a pair of parallel horizontally spaced arm portions (16, 18);
- 2. magnetic means (2) connected with one of said arms for defining a magnetic field;
- and
- 3. flux-responsive means connected with the other of said arms, said flux responsive means including
- a. a search coil (26);
- and
- b. magnetic brake switch means (24) operable between first and second conditions when the level of the flux detected thereby is above and below a given value, respectively;
- b. a ferromagnetic vane (10) adapted for vertical connection with the other of said car and shaft components to extend between the arms of said body members during vertical movement of the car and thereby vary the flux transmitted to said search coils and said brake means, said sensing means being vertically spaced a distance at least as great as the vertical dimension of the vane;
- c. electrical signal generating means (30) for connecting the search coils of said sensing means in opposition and for supplying to the elevator motor an electric signal which is a function of the rate of change of the variation in magnetic flux produced by the passage of said vane between the arms of said sensing means, thereby to decelerate the car as it approaches the floor stop position;
- and
- d. brake means (28) operable by said brake switch means for braking the car when it is in the desired floor stop position.
Dependencies are inferred from the claim text.