Braking system for an electrically-operated road such as an escalator

Claim 2

A braking system for a power-operated road means for transporting passengers along a vertical component of running, comprising: first means for producing a running direction signal correlated to the running direction of said power-operated road means; emergency switching means for automatically generating an emergency signal when an emergency condition occurs when said road means should be secured against movement; braking means for generating braking force acting to stop said power-operated road means in response to said emergency signal from said emergency switching means; and said braking means including brake force control means, providing an ascent braking force in response to the running direction signal from said first means indicating an ascent road running and providing a descent braking force substantially greater than said ascent braking force in response to the running direction signal from said first means indicating a descent road running.

Claim 3

A braking system for the road means in accordance with claim 1, wherein said braking means has at least one auxiliary braking means and a main braking means; and said braking force control means operates only said main braking means in response to said first means indicating an ascent road running, and operates both said main and auxiliary braking means in response to said first means indicating a descent road running.

Claim 4

A braking system for the road means in accordance with claim 1, including a prime mover for driving the power-operated road; said braking means including a rotatably mounted drum drivingly connected to said prime mover, brake shoe means mounted for movement into and out of engagement with said drum for producing the braking force, lever means having a first closed position holding said brake shoes in engagement with said drum to produce the braking force and having a second opened position holding said brake shoes out of frictional engagement with said drum, spring means biasing said lever means into its closed position, electromagnetic means for producing a force upon said lever means in opposition to said spring bias to move said lever means from its closed position to its opened position against said spring bias, and second switching means for selectively energizing said electromagnetic means when there is no emergency signal being produced by said emergency switching means and for deenergizing said electromagnetic means in response to an emergency signal from said emergency switching means; and said braking force control means changing the force supplied by said spring means automatically in response to the running direction signal produced by said first means.

Claim 5

A braking system for the road means in accordance with claim 3, wherein said spring means includes at least one spring having opposite ends respectively acting between a reference portion and said lever means, and said braking force control means automatically changing the position of the reference portion in response to said running direction signal.

Claim 6

A braking system for the road means in accordance with claim 3, wherein said spring means includes a main spring acting upon said lever means and at least one auxiliary spring acting upon said lever means, and said braking force control means applying a lesser number of springs to act upon said lever means during ascent that are applied during desceNt.

Claim 7

A braking system for the road means in accordance with claim 5, wherein said power-operated road means is an escalator, said prime mover is an electric motor, including power switching means selectively connecting said electric motor to a power supply for running said electric motor in opposite directions.

Claim 8

A braking system for the road means in accordance with claim 1, wherein said braking force control means includes an electric delay circuit for automatically delaying a predetermined period of time after the application of the ascent braking force during ascent running sufficiently for stopping the road and immediately thereafter increasing the braking force to resist downward slipping of the stopped road means under load.

Claim 9

A braking system for the road in accordance with claim 1, wherein said braking means includes a spring for producing the braking force and electromagnetic means for preventing the application of the spring braking force; and said braking control means changes the force of said spring according to the running direction.

Claim 10

A braking system for the road means in accordance with claim 8, wherein said braking means includes a brake shoe and a lever extending between one end of said spring and said brake shoe; and said braking force control means including reference abutment engaging the opposite end of said spring, a stationarily mounted threaded shaft, a nut threadably engaged and rotatably mounted on said shaft in abutting axial engagement with said reference abutment, a reversible electric motor, and a gear drivingly connected to said reversible electric motor and in inter-meshing engagement with said nut.

Claim 11

A braking system for the road means in accordance with claim 1, wherein said braking means includes a brake shoe, a pivotally mounted lever means for engaging said brake shoe, spring means for applying a spring bias to said lever means in the direction for applying the braking force and further for producing the braking force, and first and second electromagnetic means, each for engaging said lever means and for moving said lever means against said spring bias out of braking shoe engagement when energized; said braking force control means deenergizing only one of said electromagnetic means under emergency conditions in the ascent running direction and deenergizing both of said electromagnetic means under emergency conditions in the descent direction.

Claim 12

A braking system for the road means in accordance with claim 1, wherein said braking means includes a brake shoe, a pivotally mounted lever means for engaging said brake shoe, spring means for applying a spring bias to said lever means in the direction for applying the braking force and further for producing the braking force, and electromagentic means having two axially aligned movable core portions within one magnetic field producing means; said electromagnetic means having first tie rod means attached to one of said portions, extending through the other of said portions and being drivingly connected to one end of said spring means, and second tie rod means attached to the other of said portions, extending through said one portion and being drivingly connected to the other end of said spring means.

Claim 13

A braking system for the road means in accordance with claim 1, including a prime mover for driving the power-operated road means and braking means including a rotatably mounted member drivingly connected to said prime mover for rotation with running of said power-operated road means, brake shoe means mounted for movement into and out of engagement with said rotatable member for producing the braking force, first spring means biasing said brake shoe means toward said rotatably mounted member; first electromagnetic means for holding said brake shoe means out of engagement with said rotatably mounted member against the bias of said first spring means when energized, and when not energized permitting said first spring means to move said brake shoe means into engAgement with said rotatably mounted member; second spring means for biasing said brake shoe means into engagement with said rotatably mounted member to produce a braking force in addition to the braking force produced by said first spring means biasing said brake shoe means into engagement with said rotatably mounted member; second electromagnetic means preventing the application of the spring bias of said second spring means to said brake shoe means when energized and permitting the application of the spring bias of said second spring means in the direction of engagement of said brake shoe means and said rotatably mounted member when deenergized; and said braking force control means normally energizing both of said first and second electromagnetic means in the absence of an emergency signal, deenergizing said first electromagnetic means and maintaining said second electromagnetic means energized in response to an emergency signal from said emergency switching means and a running direction signal from said first means indicating an ascent road running, and deenergizing both of said first and second electromagentic means in response to an emergency signal from said emergency switching means and a running direction signal from said first means indicating a descent road running, so that only the bias of said first spring means is applied to produce the braking force between said braking shoe means and rotatably mounted member under emergency conditions during ascent and further so that the spring bias of both said first and second spring means is applied to produce a correspondingly larger braking force between said brake shoe means and said rotatably mounted member under emergency conditions during descent.

Claim 14

A braking system for the road means in accordance with claim 12, wherein said braking force control means includes an electric delay circuit for automatically delaying a predetermined period of time after the application of the ascent braking force during ascent running sufficiently for stopping the power-operated road means and immediately thereafter deenergizing both said first and second electromagnetic means for applying the spring bias of both said first and second spring means under emergency conditions to resist downward slipping of the emergency stopped power-operated road means under load.

Claim 15

A braking system for the road means in accordance with claim 12, wherein said brake shoe means includes a brake shoe drivingly connected to a pivotally mounted lever mounted for movement between an opened position out of engagement with said rotatably mounted member and a closed position in engagement with said rotatably mounted member; said first spring means directly engaging said lever to bias it towards said rotatably mounted member in both said opened and closed positions; said first electromagnetic means directly engaging said lever to move it from its closed position to its opened position when energized against the bias of said first spring means; said second electromagnetic means holding said second spring means out of engagement with said lever in both said opened position and closed position when energized and applying the spring bias of said second spring means only when deenergized by permitting engagement of said second spring means with said lever in both said opened and closed positions.

Claim 16

A braking system for the road means in accordance with claim 12, wherein said brake shoe means includes two brake shoes engaging opposite sides of said rotatably mounted member, two levers drivingly connected respectively to said two brake shoes and being pivotally mounted for movement between opened and closed positions; and wherein said first spring means engages between said levers to simultaneously bias them towards their closed position, said first electromagnetic means engages between said levers to simultaneously drive them from their closed position to their opened position against the bias of said first spring means, and said second spring means and second eLectromagnetic means applying the bias of said second spring means simultaneously to said levers when said second electromagnetic means is deenergized and completely removing the bias of said second spring means when said second electromagnetic means is energized in both of said opened and closed positions.

Claim 17

A braking system for the road means in accordance with claim 15, wherein said braking force control means includes an electric delay circuit for automatically delaying a predetermined period of time after the application of the ascent braking force during ascent running sufficiently for stopping the power-operated road means and immediately thereafter deenergizing both said first and second electromagnetic means for applying the spring bias of both said first and second spring means under emergency conditions to resist downward slipping of the emergency stopped power-operated road means under load.

Claim 18

A braking system for the road means in accordance with claim 15, wherein said levers are pivotally connected together, said brake shoes and at least one of said first and second spring means and at least one of said first and second electromagnetic means are mounted on the same side of the pivots of said levers.

Claim 19

A braking system for the road means in accordance with claim 17, wherein the other of said spring means and the other of said electromagnetic means are mounted on the same side of the lever pivots as said brake shoes.

Claim 20

A braking system for the road means in accordance with claim 17, wherein the other of said spring means and the other of said electromagnetic means are mounted on the opposite side of the lever pivots from said brake shoes.

Claim 21

A braking system for the road means in accordance with claim 17, wherein the pivotal connection between said levers is provided by link means pivotally connected at one end to one of said levers and at its opposite end to the other of said levers; said first spring means comprising a rod on the opposite side of said rotatably mounted member from said link means and being secured at one end to one of said levers and having a spring abutment at its opposite end, and a compression spring between said spring abutment and the other of said levers; said first electromagnetic means having a single electromagnetic coil, a first core member movably mounted within said coil and drivingly connected to one of said levers and a second core member movably mounted within said coil and drivingly connected to the other of said levers; said electromagnetic coil being mounted between said levers on the same side of said rotatably mounted member as said first spring means; the driving connection between each of said movably mounted core members and its respective lever comprising at least one rigid rod fixedly connected at one end to its respective core member, fixedly connected at its opposite end to its respective lever and intermediate said ends extending through the other of said core members.

Claim 22

A braking system for the road means in accordance with claim 20, wherein said second spring means is a coil compression spring, and wherein said second electromagnetic means includes an electromagnetic coil, two separate core members movably mounted with respect to each other and with respect to said coil and being mounted within said coil for axial movement in the axial direction of said coil spring, a rod drivingly connected at one end to one of said core members and at its opposite end to one end of said coil spring for compressing said coil spring upon movement of the core members into said coil upon energization of said coil; said core members and coil being positioned between said levers.

Claim 23

A braking system for the road means in accordance with claim 21, wherein said second electromagnetic means includes a second rod drivingly connected at one end to the other of said core members and at its opposite end to the other end of said coil spring for further compressing said coil spring when said other core member moves intO said coil upon energizing the coil.

Claim 24

A braking system for the road means in accordance with claim 21, wherein said second electromagnetic means includes a second coil compression spring on the opposite side of said coil and core members from said first mentioned coil spring, and a second rod drivingly connected at one end to the other of said core members and drivingly connected at its opposite end to the second coil spring; means drivingly connecting the ends of both of said coil springs opposite from their connection with their respective rods to the opposite axial ends, respectively, of said electromagnetic coil.