Brakes – Operators – Speed-responsive
Reexamination Certificate
1998-06-08
2001-05-01
Oberleitner, Robert J. (Department: 3613)
Brakes
Operators
Speed-responsive
C188S065100, C192S1050BA, C254S267000, C254S391000, C187S350000
Reexamination Certificate
active
06223868
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority of European Patent Application No. 97810359.6 filed Jun. 9, 1997, the subject matter of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a brake mechanism for a device for hauling up/down by rope, in particular one for the safe hauling up and down by rope of persons and loads. The device has a pulley which preferably has a back stop that prevents the pulley from turning during the roping down.
In accordance with the European published patent EP-A-0 480 117 by the applicant, such devices for hauling up/down by rope are preferably used for hauling persons or loads up and down on a rope. The preferred area of application is for rescue services or in general as mobile equipment. The devices for hauling up/down by rope essentially function to reduce the retaining force during the roping down in connection with a safety to prevent an uncontrolled dropping of the person or load attached to the rope.
These known devices for hauling up/down by rope have a large-volume pulley equipped with a back stop. In most cases, a rope is placed with 2.5 windings around this pulley. The device is operated such that when pulling up, the pulley is running freely and represents only a low resistance. During the roping down, on the other hand, the pulley is blocked by the back stop and the rope slides over the surface of the pulley. The resulting friction takes over a large portion of the load attached to the rope.
As a safeguard during the roping down, the International Patent Application WO-A-9 717 107 suggests providing a self-activating rope stop on the pull side of the device for hauling up/down by rope. The advantage of this arrangement is that the rope stop only needs to take over a portion of the load since the device for roping up/down accepts the largest portion of the pull.
However, the disadvantage of this solution is that upon reaching the critical roping down speed, the roping down operation is stopped completely. In particular if a roping down speed near the permissible limit, e.g. 2 m/s, is required, a brief exceeding of this speed limit can trigger the stopping of the rope.
SUMMARY OF THE INVENTION
It is the object of the present invention to specify a device, which prevents an increase in the roping down speed above a predetermined limit value during the roping down operation.
In accordance with the present invention, the rope brake mechanism comprises rope speed measuring means that cooperates with a rope brake, which acts upon the rope to exert a braking force onto the rope when the rope speed increases above a maximum predetermined speed.
A brake mechanism is installed on the pull side of a device for hauling up/down by rope, which mechanism forces the engagement of a frictional brake on the rope, preferably only during the roping down, if a predetermined rope speed is exceeded. In particular, the brake mechanism increases the braking effect of the frictional brake with increasing rope speed, so that the roping down speed does not reach an unacceptable, uncontrollable speed, even for heavy loads.
The present invention relates to a device for raising and lowering a load, and the device includes a pulley and a brake mechanism. A rope is wound about the pulley, and the brake mechanism acts upon the rope to exert a braking force on the rope when the rope speed increases above a maximum predetermined speed. The break mechanism includes at least two flyweights and at least one bearing surface. The rotatable arrangement of flyweights is operatively connected to the pulley and rotates about an axis in response to rotation of the pulley. The bearing surface is operatively connected to the flyweights and is movable against the rope in response to rotation of the flyweights. When the pulley is rotated, the centrifugal force exerted on the flyweights is transferred axially to the bearing surface, which causes an increased braking effect on the rope. The braking effect increases with increasing rotational speed.
The flyweights surround a rotatable core in a symmetrical arrangement, and from the core originates a radial guide means. The radial guide means holds the flyweights such that they can be moved radially. The arrangement of flyweights is surrounded peripherally by a spring-elastic element, which biases the flyweights toward the core. In addition, a frictional wheel bears against the rope and is linked to the flyweights, and a gear is arranged between the frictional wheel and the flyweights in order to establish a gear ratio, as well as a rotational link.
The rope moves through an essentially tube-shaped rope guide proximate the pulley, and the width of the rope guide can be changed. The rope guide includes convexities and concavities to force the rope into an increasingly S-shaped course during the reduction of the width so as to increase the braking effect on the rope. At least a section of the rope guide is movable so as to allow the change in width for the rope guide, and the movable section can be moved by a coupling means. The coupling means include contact zones that are angled relative to the rotational axis of the flyweights to convert radial movement of the flyweights to a movement of the coupling means directed along the rotational axis.
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patent: 5738339 (1998-04-01), Kuryu
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patent: 0480117 (1992-04-01), None
patent: 97 17107 (1997-05-01), None
King Bradley
Mau & Krull, P.A.
Oberleitner Robert J.
Rollgliss AG
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