Programmed braking for elevators and the like

Claim 2

Elevator apparatus for performing a transitionless elevator braking program, said apparatus comprising: an elevator, an electric motor for powering said elevator, a destination floor, means for producing an electric signal proportional to the speed of said elevator, preprogrammed means for producing a signal which is a continuous function of the displacement of said elevator from said destination floor without interruption until its arrival at said destination floor, variable force brake means, and control circuit means for said brake means, said control circuit means including difference means for producing a signal which is a function of the difference between the signal produced by said preprogrammed means and said speedproportional signal, and means for supplying said difference signal to said brake means for varying the brake force in accordance with said difference signal without interruption until the arrival and stop of said elevator at said destination floor, whereby said transitionless elevator braking program is provided until said arrival and stop.

Claim 3

Elevator apparatus according to claim 1, wherein said variable force brake means includes an electromagnetic winding for reducing braking force as excitation thereof is increased, and said means for supplying said difference signal to said brake means is continuously connected to said winding until the arrival of said elevator at said destination floor.

Claim 4

Elevator apparatus as in claim 2, further comprising means for disconnecting said brake control circuit means from said winding when said elevator arrives at said destination floor.

Claim 5

Elevator apparatus according to claim 2, further comprising switching means for deenergizing said electric motor whenever said brake control circuit means is in operation.

Claim 6

Elevator apparatus as in claim 4, further comprising means for maximally energizing said winding to reduce said brake force to a minimum whenever said electric motor is energized.

Claim 7

Elevator apparatus according to claim 2, wherein said variable brake means includes a brake drum and a member operatively engageable therewith for exerting a braking torque therEon, means for biasing said member toward said drum to exert maximum torque thereon, said electromagnetic winding being in operative relation with said member for exerting a torque reducing force on said member which varies as a function of said difference signal.

Claim 8

Elevator apparatus according to claim 6, wherein said biasing means comprises a spring.

Claim 9

Elevator apparatus according to claim 2, wherein said preprogrammed means comprises a voltage source, a plurality of impedances; and discrete switching means located at spaced locations whereby to be responsive to the distance between a preselected point on said elevator and a preselected stationary point for selectively connecting said impedances across said voltage source in discrete steps for varying the output signal produced thereby as a function of the spacing between said switch locations and of the travel of said elevator.

Claim 10

Elevator apparatus as in claim 8, further comprising integrating means for smoothing said discrete switching transitions to provide a smooth output from said preprogrammed means.

Claim 11

Elevator apparatus according to claim 8, wherein consecutive spacings between said switch locations are related nonlinearly.

Claim 12

Elevator apparatus according to claim 8, wherein said switching means comprises two groups of switches, one of said groups for upward elevator movement and the other of said groups for downward elevator movement, and said plurality of impedances comprise two groups of series connected resistors for connection across said voltage source, one of said resistor groups for connection during upward elevator movement and the other of said resistor groups for connection during downward elevator movement, said one group of switches for selectively connecting the resistors from said one group into and out of circuit across said voltage source; and said other group of switches for selectively connecting the resistors from said other group into and out of circuit across said voltage source.

Claim 13

Elevator apparatus according to claim 11, wherein said switches are borne by said elevator and include vertically spaced actuating members, and a stationary operating member means is secured adjacent said elevator in the path of travel of said actuating members for engaging said actuating members to operate said switches, said actuating members in each group being variably spaced in accordance with a parabolic relationship with the uppermost actuating members in said one group being maximally spaced and the lowermost actuating members in said other group being maximally spaced.

Claim 14

Elevator apparatus according to claim 12, wherein said stationary operating member means comprises a pair of operating members, one for engaging the actuating members of said one group of switches and the other for engaging the actuating members of said other group of switches.

Claim 15

Elevator apparatus according to claim 13, wherein said elevator is adapted to stop at a plurality of vertically spaced preselected points when moving upwardly and downwardly, said operating member means comprising a pair of said operating members for each of said points.

Claim 16

Elevator apparatus according to claim 11, wherein each of said switches is operable between a normal and an operated position, said switches being borne by said elevator and including vertically spaced actuating members, and a stationary operating member means is secured adjacent said elevator in the path of travel of said actuating members for engaging said actuating members to operate said switches, circuit means for connecting each group of switches with its associated group of resistors, said circuit means being so arranged that when all of said switches are in their normal conditions, all of the associated resistors are short circuited, and when during upward elevator movement the uppermost switch actuating member in said one group is engaged by said operating member means, one of said resistors from said first group is connected across said voltage source, aNd as each successive actuator in said one group is engaged by said operating member means, an additional resistor from said one group is connected across said voltage source; said circuit means being further arranged so that when during downward elevator movement the lowermost actuator in said other group is engaged by said operating member means one of said resistors from said other group is connected across said voltage source, and as each successive actuator in said other group is engaged by said operating member means an additional resistor from said other group is connected across said voltage source, and selector switch means responsive to elevator direction for applying said voltage source to said one groups of switches and resistors and to said other groups of switches and resistors.

Claim 17

Elevator apparatus according to claim 11, wherein said switches are magnetic switches comprising contacts movable between a normal position and an operated position, a magnet for each switch spaced from said contacts for biasing said contacts to their normal position; and stationary operating member means for said switches secured adjacent said elevator for interposition between said contacts and their associated magnet, said stationary operating member means being made of ferromagnetic material for shielding said contacts from said magnets whereby to cause said contacts to move to their operated positions.

Claim 18

Elevator apparatus according to claim 1, further comprising motor control circuit means including a time dependent starting program signal producing means, means for producing a signal which is a function of the difference between the voltage produced by said starting program means and said proportional signal, and means for controlling the energization of said motor in response to said last mentioned difference signal.

Claim 19

Elevator apparatus according to claim 11, further comprising motor control circuit means including a time dependent starting program signal producing means, means for producing a signal which is a function of the difference between the voltage produced by said starting program means and said proportional signal, and means for controlling the energization of said motor in response to said last mentioned difference signal.

Claim 20

Elevator apparatus according to claim 17, wherein said energization controlling means comprises a saturable core reactor.

Claim 21

Elevator apparatus according to claim 17, wherein said motor is a multiphase motor, and said energization controlling means comprises a plurality of saturable core reactors, one in series with each phase of said motor.