US 4,351,417 A · Speed retarder

Abstract

A speed retarder used in combination with a flexible member such as rope, cable, or chain to control the speed of the flexible member relative to the speed retarder. The speed retarder is particularly suited for use in applications where it is desirable to lower a load at a controlled rate of speed from a higher elevation to a lower elevation. Such applications include fire escape devices and safety backup devices for elevators. One specific embodiment of the speed retarder comprises a frame having an axle on which is mounted a pair of rollers each having a tapered surface around which a flexible member is trained and retained between the surfaces by means of guides. The wheels are mounted on the axle for combined rotary and outward sliding motion into brake pads carried by the frame outboard of the wheels. Tension on the flexible member combined with movement thereof causes the wheels to be forced outwardly into pressure engagement with the brake pads, thereby creating friction on the outsides of the wheels to slow the same and thus to retard the speed of the flexible member relative to the frame.

Claims22

Dependent claims

A speed retarder for use with a flexible member comprising:

a frame,
an axle mounted in said frame;
a pair of wheels rotatably mounted on said axle with at least one wheel of said pair also being axially movably mounted on said axle,
at least said one wheel having an outboard braking surface and a tapered inboard surface,
another wheel of said pair of wheels having an inboard surface confronting said tapered surface to define a peripheral gap therebetween,
brake pad means carried in said frame and operable upon outward sliding movement of said one wheel to slidably engage said one wheel with a continuous axially inward pressure operable to create between said one wheel and said frame friction acting counter to the rotational direction of said one wheel, with said pressure, and hence said friction, being directly related to the tension on the flexible member,
guide means carried by said frame for engaging said flexible member and maintaining the same engaged in said wheel gap through a predetermined arcuate extent,
whereby motion of the flexible member with tension thereon urges said one wheel outwardly to create said friction for retarding rotation of said wheels and thereby to retard the speed of the flexible member.

5 more elements

A fail-safe elevator comprising:

an upright structure having spaced members providing upper and lower levels,
a platform movable vertically between said levels,
a first member connected to said platform and movable longitudinally between said levels to provide a primary means for raising and lowering the platform,
a second elongated flexible member extending stationary between said levels,
a braking assembly carried by said platform for cooperating with said stationary flexible member to control the rate of descent of the platform in the event of failure of said first flexible member,
said braking assembly including:
a frame,
an axle mounted in said frame,
a pair of wheels rotatably mounted on said axle with at least one wheel of said pair also being slidable axially on said axle,
at least said one wheel having an outboard braking surface and a tapered inboard surface,
another wheel of said pair of wheels having a surface confronting said tapered surface to define a peripheral gap therebetween,
brake pad means carried by said frame and operable upon outward sliding motion of said one wheel to create friction between said one wheel and said frame,
guide means on said frame for engaging said flexible member and maintaining the same engaged in said gap through a predetermined arcuate extent,
whereby failure of the first member causes the load on the platform to be transferred to the second flexible member whereupon said one wheel is urged outwardly to create friction for retarding the downward speed of the platform.

11 more elements

Dependencies are inferred from the claim text.

Speed retarder

Life of this patent

Speed retarder

Life of this patent

Abstract

Claims22