Brakes – To retard rolling of caster
Reexamination Certificate
1999-03-05
2001-11-27
Butler, Douglas C. (Department: 3613)
Brakes
To retard rolling of caster
Reexamination Certificate
active
06321878
ABSTRACT:
SUMMARY OF THE INVENTION
This invention relates to hospital and long term care beds and more particularly to hospital beds having four wheels or casters attached to the base frame for rolling the bed from location to location and a braking mechanism for maintaining the bed in a desired location.
Hospital beds are typically designed to be moved from location to location and, therefore, have wheels or casters which permit the hospital bed to be rolled and steered between locations. During movement it is desirable to have free rolling wheels but upon reaching the desired location, brakes are usually applied to the wheels to maintain the bed at the desired location.
It is well known to provide hospital beds with brake/steer casters which include mechanisms for blocking the rotation of the caster wheel or wheels, i.e. braking mechanisms, and mechanisms for blocking swiveling movement of the caster wheel fork, i.e. anti-swivel or directional lock mechanisms. Some beds with four castered wheels include pedals located on opposite sides of the bed which control the braking and anti-swivel mechanisms in each caster. An example of such a bed is shown in Rudolf et al., U.S. Pat. No. 5,377,372. The pedals in Rudolf et al. may not be readily accessible by a caregiver who is currently pushing the bed.
Other hospital beds equipped with such brake/steer casters include four separate brake and/or steer pedals each associated with only one of the four casters with each brake pedal only engaging the brake on the caster with which it is associated and each steer pedal only actuating the anti-swivel mechanism on the caster with which it is associated. On such hospital beds having four casters with four unconnected brake mechanisms, prior to movement of the bed the caregiver must disengage all four brakes by operating all four pedals and after movement of the bed engage all four brakes by again operating all four pedals.
Caregivers would appreciate being able to engage the brakes on all four castered wheels by operating any one of four pedals associated with the wheels. Caregivers would also appreciate being able to engage all of the anti-swivel mechanisms on the casters having such mechanisms by operating a steer pedal on any one of the four casters regardless of whether the chosen caster includes an anti-swivel mechanism.
According to the present invention, a braking system for a hospital bed having a base frame includes a plurality of caster devices rotatably coupled to the base frame. Each caster device has a caster frame, a wheel rotatably attached to the caster frame, a brake attached for movement with respect to the caster frame between a first position in which the brake inhibits rotation of the wheel and a second position in which the brake permits the wheel to rotate freely, and an actuator. A plurality of pedals are provided with each pedal being adjacent to a different one of the plurality of caster devices and coupled to the actuator of the caster device for movement of the brake between the first position and second position in response to movement of the pedal. A linkage is coupled to all of the actuators of the plurality of caster devices so that movement of any one of the plurality of pedals causes movement of all of the actuators. The actuator includes a cam attached to a rotatable shaft and a follower coupled to the brake. Each caster devices has a sleeve, the cam and follower are disposed within the sleeve, and the shaft extends through the sleeve. The linkages are coupled to the shafts of the actuators.
The base frame has a first side frame member and a spaced apart second side frame member and at least two of the plurality of caster devices are attached to the first side frame member and at least one of the plurality of caster devices is attached to the second side frame member. The linkage includes a first side link attached for movement relative to the first side frame member of base frame and coupling the shafts of the actuators of the caster devices attached to the first side frame member and a cross shaft coupling the first side link to the shaft of the at least one of the caster devices attached to the second side frame member of the base frame. Rotation of the shaft induces rotation of the cross shaft.
At least one of the plurality of caster devices may include a steer lock attached to the follower for movement relative to the caster frame. The steer lock may assume a first state in which the caster device swivels and a second state in which the caster device does not swivel. Both the steer lock and brake are coupled to the actuator so that rotation of the rotatable shaft in a first direction places the brake in the first position and rotation of the rotatable shaft in a second direction places the steer lock in the first state.
A patient support apparatus in accordance with the present invention includes a base frame, a patient support coupled to the base frame, a plurality of casters having sleeves, and a plurality of caster mounting tubes. The caster mounting tubes have an interior configured to receive a cylindrical sleeve of a caster and a rectangular outer cross-section defined by four external side walls. One of the external side walls abuts the base frame and the plurality of caster mounting tubes are welded to the base frame. The plurality of caster mounting tubes may each include interior partially cylindrical concave wall sections configured to receive the cylindrical sleeves of the casters. Each caster includes a set screw for orienting the caster and the caster mounting tubes are formed to include notches for receiving the set screws. The side wall abutting the base frame is formed to include a hole as is the base frame, the hole in the base frame is aligned with the hole in the side wall and both holes are located between the welds.
A braking system for a hospital bed having a base frame including a first side frame member and a spaced apart second side frame member in accordance with the present invention includes a plurality of casters each having a wheel, a brake, and an actuator. A first and second of the plurality of casters are attached to one of the first and second side frame members of the bed and a third caster is attached to the other of the first and second side frame members of the bed. A link extends between, and is coupled to, the actuators of the first and second casters while a cross shaft extends between the first side frame member and second side frame member of the bed. The cross shaft has a first end coupled to the link and a second end coupled to the actuator of the third caster. The link and cross shaft are arranged so that actuation of one of the actuators of the first, second, or third casters induces actuation of the others of the actuators of the first, second, or third casters. The actuator includes a shaft, a cam mounted on the shaft, and a follower engaging the surface of the cam at a first end and coupled to a brake at a second end. The actuator is arranged such that rotational motion of the shaft induces movement of the brake. The shaft has an axis of rotation fixed relative to the base frame. The link is pivotally coupled to the shaft by a first pivot bracket fixed to the shaft and riding on a first pivot pin having a pivot axis extending through the link. The cross shaft is mounted to the frame for rotation about an axis of rotation fixed relative to the frame and is pivotally coupled to the link by a second bracket fixed to the cross shaft and riding on a second pivot pin having a pivot axis extending through the link. The displacement between the axis of rotation of the shaft and the first pivot axis is substantially equal to the displacement between the axis of rotation of the cross shaft and the second pivot axis. The link may include a vertical offset bracket through which one of the first and second pivot pins passes so that the axis of rotation of the shaft and the axis of rotation of the cross shaft are in different vertical planes. The cross shaft is rotatably mounted to a cross member extending between the first
Cunningham James D.
Larisey, Jr. William S.
Meyer Bruce A.
Mobley Donald L.
Saar James J.
Bartz C. T.
Bose McKinney & Evans LLP
Butler Douglas C.
Hill-Rom Services Inc.
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