Patent Application
20130022439
The present disclosure relates to device and method for hoisting or lowering a load. More specifically, the present disclosure relates to a life-saving rescue device that may be used to lower an injured person from an elevated location.
Pulleys are often used to hoist and/or lower loads in connection with a rope or cable, as generally known in the art. A pulley typically comprises a wheel or sheave that turns on an axis. When used in connection with a rope, a pulley can be used to change the direction of a tension force placed on the rope.
Pulleys are used in several configurations and for various purposes. One example is a block and tackle arrangement in which two pulleys work in unison, one pulley being fixed and another free to move with the load. This simple device may be used to create a mechanical advantage, wherein the tension force required to lift a load is decreased by a factor of two or more, in exchange for a decrease in the speed at which the load ascends. Some sophisticated examples of modern block and tackle arrangements use pulleys in combination with braking and/or clutch devices.
In general, block and tackle systems often require a significant amount of time to prepare for use. The time and effort spent in arranging the elements of a block and tackle system are problematic where the location of the load is remote or where the need to move a load becomes urgent. One example in which a block and tackle arrangement is often impractical is a rescue situation. For example, it is not practical to arrange a block and tackle system where a person has been injured while working in an elevated space, such as where a person has lost consciousness while working on a power line and remains suspended from the power pole.
As an example of the prior art, U.S. Pat. No. 4,220,315 discloses a pulley having an auxiliary braking system, enabling the operator (e.g., rescue personnel) to quickly assemble the device and lower the injured person in a short amount of time. The auxiliary braking system of the prior art comprises a spindle in a chamber, the path of the rope through the chamber comprises a loop of greater than 180°. The load bearing portion of the rope is suspended directly from the sheave, while the operator controls the rope entering the chamber of the auxiliary braking system. The spindle is arranged such that the axis of the spindle may move laterally within the chamber, enabling the operator to control the braking function, in part, by manipulating the angle of the rope entering the chamber.
Disadvantages of this and other existing solutions include that the braking system of currently available devices must frequently be operated from below the device. Further, the amount of complexity involved in arranging the rope in an auxiliary braking system remains high for an operator in view of the expected stress of a rescue effort.
The present disclosure provides a device, system and method for hoisting and lowering a load that provides significant advantages over the prior art. For example, the aspects of the present disclosure may be used to significantly reduce the amount of preparation time required, while also providing the operator (i.e., user) with enough resistance to have a substantial control when lowering a heavy load, even where circumstances place the operator in a precarious position, such as where the operator is at an elevated position and is working within a limited space or surface area, thereby decreasing the amount of leverage available. The system of the present disclosure may be prepared by an operator at an elevated location and allows the operator to lower the load from the elevated location prior to descending. Thus, the system of the present disclosure provides significant advantages in time and simplicity in comparison with the prior art, without sacrificing the security of the load.
One aspect of the present disclosure provides a device for hoisting or lowering a load, comprising a friction accessory attached to a pulley, the pulley comprising a main body, a sheave, and a front plate. The front plate is configured to have a closed position and an open position, the open position exposing a chamber between the sheave and the main body. The friction accessory may be a hook-shaped appendage extending from the bottom of the pulley, and formed integral therewith.
In another aspect of the present disclosure, the device described herein is used as a component of a system, wherein a cord may be connected to the device and attached to a load, and the device may be attached to a support structure. The device is oriented such that the weight of the load creates friction between the cord and the device. In some embodiments the load may be a victim, such as an injured person.
Yet another aspect of the present disclosure provides a method for rescuing a victim using the device and system described herein. The device is secured to a support structure. The rope is placed in the device, for example, by moving the front plate to an open position, loading the rope into the chamber, and replacing the front plate to the closed position. The rope is then placed through the friction accessory and attached to the victim. Finally, the victim is hoisted or lowered as necessary to complete the rescue.
Other systems, methods, features, and advantages of the present disclosure will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. The features, functions and advantages that have been discussed can be achieved independently in various embodiments of the present invention or may be combined in yet other embodiments further details of which can be seen with reference to the following description and drawings.
Many aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
In the following description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown, by way of illustration, various embodiments of the present disclosure. It is understood that other embodiments may be utilized and changes may be made without departing from the scope of the present invention.
The device 100 is designed to withstand significant stresses placed upon it as a load is hoisted or lowered. In particular, the main body 105 is be configured to withstand the greatest portion of the stresses caused by the weight of the load. As seen in
The friction accessory 115 is designed to create a significant amount of friction between a cord (e.g., a rope or cable) and the device 100, without causing damage to the cord. The friction accessory is attached to the main body 105 and comprises an elongated appendage which may have one or more turns or twists therein, such as the hook shape shown in
In some embodiments, the friction accessory 115 is also connected to the main body 105 by one or more gates 120 which extend from the main body 105 and contact an end 118 of a corresponding arm 117 when in a closed position. For example,
The present disclosure further contemplates various alternative designs of a friction accessory 115, wherein the friction accessory 115 may have a more constricting enclosed area 121, or where the friction accessory 115. Other configurations of a friction accessory 115 may comprise an enclosed area 121 with an adjustable width, (e.g., a pinching device), such that the amount of friction resulting from the friction accessory 115 may be adjusted for a particular application.
In some embodiments, the friction accessory 115 may be assembled without a gate, as in the embodiment illustrated in
The sheave 130 of the device 100 may comprise a substantially cylindrical structure, wherein the bolt 125 passes approximately through the axis thereof. In some examples, the sheave 130 is configured to rotate about the bolt 125, facilitating the movement of a cord in hoisting or lowering a load. The sheave 130 may be formed having a concave profile along the periphery of the cylinder, to accommodate a cord. The material of the sheave 130, the structural strength, and other features may be chosen according to general specifications for sheaves and pulleys, as known in the art.
The front plate 140 is located at a distal end of the bolt 125 (i.e., at the end of the bolt 125 furthest from the main body 105). In some embodiments, as shown in
In each of the illustrated examples, the front plate 140 is configured to rotate about the bolt 125. The front plate 140 may alternatively be configured to reveal a side the chamber 160 by rotating about a hinge or folding upon itself. The chamber 160 is open at each end thereof between the front plate 140 and the main body 105. In some embodiments, where the front plate 140 rotates about the bolt 125, the main body 105 is formed having a front comprising a recess 106 and a front face. The recess 106 is set back from the front face 107, and is formed to have a shape corresponding to the shape of the front plate 140. In this configuration, the recess 106 allows the front plate 140 to reach a closed position abutting a portion of the front face 107 and the main body 105. This arrangement constrains the rotation of the front plate 140 such that the rotation will occur in only one direction from the closed position. Limiting the movement of the front plate 140 to one direction provides a predictable movement for the operator, and therefore aids the operator in quickly preparing the device 100 to operate as part of a system for hoisting and lowering a load. Such a feature is an important consideration, where, for example, one of the embodiments discussed herein contemplates the use of the device in a rescue situation by an operator that may be wearing heavy, electrically-insulated gloves.
To hold the front plate 140 in the closed position, some embodiments comprise a releasable clasp 145. The releasable clasp 145 holds the front plate 140 in the closed position and allows the operator to control the opening of the front plate 140, thereby controlling access to the chamber 160. The releasable clasp 145 may be located between the main body 105 and the front plate 140 at any point where the two are adjacent when in the closed position. For example, the releasable clasp 145 may be located within the area of the recess 106 (as shown in
In some embodiments, the releasable clasp 145 is configured attach the front plate 140 to the main body 105 by latching onto a physical feature of the front plate. For example, in
The releasable clasp 145 may comprise any suitable clasp or brake that performs the function described above, as may be known in the art. For example, the releasable clasp 145 may comprise a release button. In some examples, such as the embodiment illustrated in
In some embodiments, the device 100 further comprises a fastener 110 that can be used to secure the device to a support structure (see
Another aspect of the present disclosure, an embodiment of which is illustrated in
The system 400 of the present disclosure is intended to allow an operator 420 to hoist or lower a load 430 with minimal effort. In particular, the system 400 of the present disclosure may be used to significantly reduce the amount of preparation time, while also providing the operator (i.e., user) with enough resistance to have a substantial control when lowering a heavy load, even where circumstances place the operator 420 in a precarious position, such as where the operator 420 is at an elevated position and is working within a limited space or surface area, thereby decreasing the amount of leverage available.
Referring to the description of the device above, the cord 440 is arranged relative to the device 100 such that the load bearing portion 440a descends from a friction accessory 115 of the device. Accordingly, the restraining portion 440b of the cord 440 is in contact with the sheave 130 at a point within chamber 160. This arrangement is simple to complete, even for an operator 420 located at an elevated location, equal to or higher than the device 100. In comparison to the prior art, the system may be prepared by an operator 420, having ascended to an elevated location for example where an injured person is suspended, and further allows the operator to lower the load from the elevated location.
The operator 420 may be in any orientation relative to the device 410. In situations where the system 400 is used to hoist a load 430 and where the operator 420 is located directly above the device 100, such that the restraining portion 440b is substantially vertical, the device 100 could potentially turn to one side or the other and place the cord 440 in a position relative to the device 100 that very little friction is created between the device 100 and the cord 440. Referring to the description of the device above, one example of a solution is to provide the device 100 with a second fastener, such as on the back of the main body 105 or connected to the friction device, thereby connecting the device 410 of system 400 to the support structure 450 in at least two places, thereby fixing the orientation of the device 410. Alternatively, the main body of the device may be constructed to have a narrow top portion above the sheave, thereby allowing the rope to come in contact with the sheave from a variety of angles without causing undue stress on the main body.
The manner in which the cord is engaged with the friction accessory may have a large impact on the amount of friction, and can be adjusted accordingly to manage the weight of the load. In some examples, the cord is wrapped around a vertical portion of the friction accessory, as shown in
The operator 420 may be a person, as depicted in
The load 430 that is hoisted or lowered by the system 400 may be any item that requires hoisting or lowering. The system 400 is particularly useful in connection with lowering a heavy load where the situation provides very little time or resources for preparing a lowering mechanism. In an alternative example, the device 100 is used to lower a load 430, where the load 430 comprises an injured person, from an elevated location. Some other examples of a load 430, where expediency may be required, include hazardous materials, heavy equipment, or another item having an impact on safety. Further, various embodiments of the system 400 of the present disclosure may be employed to avoid the negative impact of an externality, such as a thunderstorm or other natural or man-made emergency.
The system 400 is described above as comprising a cord 440, but the rope may be a cable or wire rope. The cord (e.g., a rope or cable) of the system may be manufactured from any suitable material for the application. Durability and strength are key factors in determining what cord to use in any particular application. Such choices are within the scope of those knowledgeable in the art.
The system 400 is useful to hoist or lower a load 430 where the device 410 is attached to a support structure 450. The support structure 450 may comprise a building, a wall, a fence, a vehicle, a scaffold, a power pole, or any other structure capable of support the weight of the load 430. The support structure 450 may further comprise a device for connecting the device 410 to the support structure 450, such as a hook or a cable connected to the support structure 450.
Other embodiments of the system may be arranged to create a mechanical advantage. One example of a system with a mechanical advantage similar to a set-of-fours is constructed with the device, secured to a support structure, and a cord. The cord is loaded into the chamber, the cord comprising an end with a loop or an eye. The loop or eye is then placed over an end of the friction accessory. A bight of the cord, between the device and the loop or eye, is then passed through an eye or other opening of a fastener attached to the load. The bight of cord is then placed over an end of the friction accessory, similar to the loop or eye in the end of the cord. The result is an arrangement whereby the operator can use the restraining portion of the cord to hoist the load using a mechanical advantage of 2 to 1, ignoring friction.
In operation, the device and system of the present disclosure may be employed as part of a method for hoisting and/or lowering a load.
The hoisting device is first secured to a structure. (STEP 610). The device may be any example of a device in accordance with the present disclosure. The structure may be any structure capable of supporting the load that is being lifted, and may comprise a person. The structure may further comprise a device or feature that enables the attachment of the device to the structure, such as a hook or a harness.
The device is prepared for use by moving the front plate to an open position. (STEP 620). In some embodiments, this step is performed by disengaging the releasable clasp and swiveling the front plate from the closed position to an open position, thereby opening the chamber and gaining general access to the sheave. Once the front plate is placed in an open position, a bight of cord may be loaded into the sheave. (STEP 630). Once the cord is in position against the sheave, the front plate may be returned to the closed position and the releasable clasp engaged. (STEP 640).
The method of the present disclosure further provides a step of passing the cord through the friction accessory. (STEP 650A). The rope is placed in the friction accessory in a manner that will roughly create the desired amount of friction. In some instances, the operator may choose to wrap the cord around a portion of the friction accessory more than once, so long as the cord is still capable of moving against the friction accessory in hoisting or lowering the load.
Another step comprises attaching the cord to the load. (STEP 650B). The step of attaching the cord to the load may include tying a knot around the load, attaching an end of the cord to a fastener, or any other method known in the art. While the steps of the method described in the present disclosure are not strictly limited by a particular order, many of the steps have a relative order that aids in the performance of the method. The respective steps of placing the rope in the friction accessory and attaching the cord to the load, are particularly interchangeable, depending on the circumstances. Where the load is partially suspended prior to using this method, the method is best employed by engaging the cord with the friction accessory prior to attaching the rope to the load.
With the rope and device in place, the operator may then perform the step of hoisting or lowering the load. (STEP 660). As explained above, the method of the present disclosure provides particular advantages when lowering a load because the friction created will tend to reduce the amount of force required to keep the load suspended from the device. Still, the method of the present disclosure does provide some advantages in hoisting a device as well. In particular, while the friction works against the operator when lifting, the friction provides the operator with some security against dropping the load and allows the operator to pause while hoisting the load without losing progress, so long as some tension is continuously placed on the cord.
It should be emphasized that the above-described embodiments of the present apparatus and process are merely possible examples of implementations and merely set forth for a clear understanding of the principles of the disclosure. Many different embodiments of the disclosure described herein may be designed and/or fabricated without departing from the spirit and scope of the disclosure. All these and other such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims. Therefore the scope of the disclosure is not intended to be limited except as indicated in the appended claims.
This application claims priority from U.S. provisional application Ser. No. 61/572,608, filed Jul. 19, 2011.
| Number | Date | Country | |
|---|---|---|---|
| 61572608 | Jul 2011 | US |
