Patent Application
20090000879
The present invention relates to an abseiling device for braking a load that is guided on a rope and that may be attached to the abseiling device, with which the rope passes through the abseiling device via a section in a friction-guided manner.
A device of this type is known from DE 10 2006 009 332 A1. With the known device, the frictionally-guided section for the rope and a brakable shaft are provided, the rope being pressed against the brakable shaft with a specifiable contact pressure. This abseiling device therefore has the advantage that the shaft brake may be designed small in size, since the shaft brake is supported in its braking operation by a frictionally-guided section. Since it is possible to adjust the contact force with which the rope is pressed against the brakable shaft, the abseiling device may be adjusted for loads having different weights. A bit of experience is required, however, to correctly adjust the contact force to the particular load weight. It cannot be ruled out that misuse will occur, which could result in the load being lowered too rapidly or the abseiling device becoming blocked.
The object of the present invention is to provide an abseiling device that automatically adapts itself to the weight of the load to be lowered, and that may therefore be used for a large bandwidth of load weights, without manual intervention.
The object is attained according to the present invention in that at least one portion of the frictionally-guided section is guided via a part that is movable out of an unloaded starting position relative to a housing 12 of the abseiling device, which, when a load is suspended, generates a frictional force on the rope that is a function of the weight of the load.
The inventive abseiling device has the advantage that the load weight results in a certain deflection or displacement of the movable part, thereby resulting in a frictional force being automatically produced that acts on the rope and makes it possible to lower the load with a controlled speed. When the loads are heavy, the frictional force that is produced is greater than it is with lighter loads. With the inventive abseiling device, it is therefore possible to lower loads of, e.g., 30 kg to 200 kg, without the need to manually adjust the frictional force.
The movable part may preferably exert a frictional force on the rope by pressing the rope against a fixed surface of the abseiling device. Depending on the magnitude of the displacement of the movable part, the distance between the movable part and the fixed surface in the region of the rope guide may be increased or reduced. It is also possible for the rope to be deflected—in the region of the section that is guided via the movable part—by the fixed surface, and for the frictional force that is produced at the deflection point to be of a magnitude that depends on the load.
In a preferred embodiment, the fixed surface is the surface of a brakable shaft. In this case, the frictional force may be adjusted automatically to the load weight via the movable part, by changing the contact pressure of the rope against the shaft, by changing the gripping surface of the rope, and/or by changing the wrap angle of the rope.
It is particularly advantageous when the brakable shaft is braked using a centrifugal brake. Centrifugal brakes may be designed compact in size and secured to the brakable shaft; they prevent a rope from passing through the abseiling device too rapidly. The brakable shaft may have a small diameter, thereby resulting in high rotational speeds during braking. This makes it possible to use relatively small centrifugal brakes.
The unloaded starting position of the movable part may be a central position, in which no or only minimal frictional force may be exerted on the rope by the movable part. When the movable part is placed in this central position, the rope may be pulled through the abseiling device in a nearly frictionless manner to be wound up, e.g., after one is finished using the abseiling device.
In a preferred embodiment of the present invention, the frictionally-guided section is designed as a channel in the abseiling device, which has a smaller diameter than that of the rope that is guided through the abseiling device, and/or the rope is deflected multiple times away from its weight-guided direction via rollers and/or bolts, and/or the rope is guided through a winding channel, in particular being guided through the abseiling device in a meandering or serpentine manner.
The frictionally-guided section may have a different design, in order to support the brakable shaft. It is important in this context that the rope that is being guided in the device be braked adequately using a sufficient amount of frictional energy, and that the rope not be thermally overloaded in the braking procedure. The rope may therefore be guided through the abseiling device in a curved manner along this section via rigid bolts, supported rollers, constrictions, and/or more or fewer guide elements, it also being possible to provide cooling elements or slits in the device, if necessary.
In a further embodiment of the present invention, the outer surface of the rollers and/or bolts is roughened, and/or includes a material coating, and it has a higher coefficient of friction than does the rope material that was selected.
This has the advantage that the frictionally-guided section may be adjusted for the type of rope material to be used, in order to attain the best possible braking of the rope in the abseiling device.
In a further advantageous embodiment of the abseiling device, the frictionally-guided section may be a three-dimensional section, i.e., it may extend not only in one plane, but also perpendicularly thereto. This has the advantage that the frictional force required for the rope may be applied even when the housing of the abseiling device is very small. The necessary changes in direction of the rope, which generate the frictional force required, may then also be realized in housings that are roughly the size of a human hand.
In a further embodiment of the present invention, the braking device includes a rope reservoir. This has the advantage that the abseiling device may be designed in advance for certain applications, and it may be manufactured such that it is ready to use.
If the abseiling device will be used, e.g., for fire safety purposes on buildings, the rope reservoir may store the length of rope that is required to lower a person or a load safely to the ground from the highest point of a building. In addition, the inventive device may be completely pre-installed, i.e., at one end, the rope is attached to the highest point of a building, e.g., via a hook, with the abseiling device attached to the rope itself, the abseiling device including a load opening via which a load—if it is attached there—may be lowered safely to the ground from a tall height.
Advantageously, the rope may be a plastic rope, a steel rope, or a fibrous composite rope. The fibrous composite rope may be made with or without fibers made of high-strength materials. Other types of ropes made of any types of metallic materials and fibrous composite materials may also be used with the inventive abseiling device, however.
In a further embodiment, the abseiling device may be used in reciprocating operation, i.e., the housing through which a rope—which may be braked in a controlled manner—passes is fixedly attached to a retaining element, and loads may be lowered using both ends of the rope in a reciprocating operation. When a load is lowered via one free end of the rope, this free end of the rope moves away from the housing with the braking devices provided therein (braking means via frictional forces, and the centrifugal brake) in a controlled manner, while the other free end of the rope moves as close as possible to the housing of the abseiling device. Once the abseiling procedure with the one free end of the rope has ended, a new abseiling procedure may be initiated using the other free end of the rope in that the rope passes through the housing with the braking devices in the opposite direction.
If the braking device includes a brakable shaft, a hand wheel may be provided in the housing, via which the braking effect of the shaft may be influenced, e.g., using a centrifugal brake, up to the point of being completely blocked. This has the advantage that the lowering of a load may be halted at any height. When a person is lowered using the inventive abseiling device, the person may stop the abseiling device at any height and then restart the abseiling procedure by blocking or releasing the centrifugal brake using the hand wheel. If the centrifugal brake is blocked, by virtue of the fact that the brake pads press against the corresponding braking surfaces in the housing to such an extent that the rope is unable to move in the housing, the person being lowered by the rope has both hands free to use as necessary. To continue the abseiling procedure, the hand wheel is rotated in the reverse direction in order to release the centrifugal brake.
If the weights (persons, loads) to be lowered by rope are too light for the abseiling device that was selected, or if a person wants to lower himself at a higher rate of speed, the rotational motion of the brakable shaft may be supported via a hand crank. This hand-operated crank may counteract braking forces that result due to friction and/or centrifugal force.
Embodiments are also advantageous with which the desired braking effect is delayed by the abseiling device and sets in as a function of weight, i.e., the load to be lowered by rope. This has the advantage that jerky braking motions that take place when load peaks occur abruptly, due, e.g., to accelerating weights (persons who jump out of the window of a building with the inventive abseiling device), are avoided. It may be provided that, e.g., loads of more than 200 kg on a rope may be initially braked only barely, with the braking force increasing with a time delay until the desired abseiling speed sets in in a self-regulating manner via the centrifugal brake.
The inventive abseiling device is described as an example with reference to an exemplary embodiment in the figures below.
a and 4b show a partial cross section through the brakable shaft of the abseiling device in
Abseiling device 10 includes an opening 20, at which a load or person's seat harness may be attached, in order to lower the load or person's seat harness from one point to a lower point using abseiling device 10. Opening 20 may also be used to fasten device 10 when it is used for a reciprocating operation (see
A portion of frictionally-guided section 22 moves over a movable part 25, which is swivelable in this case, and which is supported on housing 22 such that it may rotate around an axle 26. In the position shown in
A further portion of section 22 is located below the plane of the drawing, i.e., it extends on the back side of housing 12. Due to this three-dimensional guidance of section 22, housing 12 may be designed with very small dimensions.
In contrast to
Abseiling device 10 may be closed using a not-shown cover, it being necessary for the cover to be supported on housing 12 in a swivelable manner, so that it may be easily opened in order to insert rope 14. To close the cover, it may be provided with an opening, which may overlap opening 20 in housing 12. A spring clip, e.g., may be guided through both openings, which closes the cover and may be used simultaneously to accommodate a load.
A sectional view through shaft 24, on which a centrifugal brake 51 is located, is shown in
The brake may also be actuated using hand wheel 50, however, which is screwed onto brake drum 52 from the outside and may be screwed further inward toward shaft 24. If this action is carried out by the user of the abseiling device, e.g., to reduce the lowering speed that sets in automatically due to the centrifugal brake, or to be able to stop during the descent, a conical contact-pressure disk located on the inside of hand wheel 50 presses centrifugal weight 53 outwardly against drum 52, thereby initiating a braking procedure independently of the rotational speed of shaft 24.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2007 030 360.4 | Jun 2007 | DE | national |
