The present invention relates to active protection devices and more particularly to camming devices.
Climbers generally use clean protection devices for two distinct purposes. First, a clean protection device may be used as a form of safety protection for protecting a climber in the event of a fall and second, a clean protection device may intentionally be used to artificially support a climber's weight. Clean protection devices cam or wedge into a crack, hole, gap, orifice, taper, or recess in order to support an outward force. The area or surface within which the clean protection device supports the outward force is considered the protection surface. The protection surface can consist of natural materials such as rock or may consist of artificial materials such as concrete.
Clean protection devices are generally divided into active and passive categories. Passive protection devices include a single object, which contacts the protection surface to support an outward force. For example, a wedge is a passive protection device because it has a single head with a fixed shape. There are numerous types of passive protection devices including nuts, hexes, tri-cams, wedges, rocks, and chocks. Active protection devices include at least two movable objects that can move relative to one another to create a variety of shapes. For example, a slidable chock or slider nut is considered an active protection device because it includes two wedges that move relative to one another to wedge into various shaped crevices. When the two wedges of the slider nut are positioned adjacent to one another, the overall width of the protection device is significantly larger than if the two wedges are positioned on top of one another. The two wedges must make contact with the protection surface in order to actively wedge the device within the protection surface. A further subset of active protection devices is camming devices. These devices translate rotational displacement into linear displacement. Therefore, a slider chock would not be an active camming device because the two wedges simply slide relative to one another and do not rotate. Camming devices include two, three, and four cam lobe devices. The cam lobes on an active camming device are generally spring biased into an expanded position and are able to rotate or pivot about an axle to retract. In operation, at least one cam lobe on either side of the unit must make contact with the protection surface for the device to be able to actively support an outward force. Some active protection devices can also be used passively to support outward forces as well.
Active protection devices are generally preferable to passive protection devices because of their ability to cam into a variety of features. For example, a standard four-cam unit has a particular camming range that allows it to cam into features within a particular size range. The two most common connection systems used in three and four cam units are single stem and double stem systems. Double stem systems include a U-shaped cable that attaches independently to two cable terminals on either end of the head of the protection device. The clip-in point of a double stem system is simply the bottom of the U-shaped cable. Single stem systems include a single cable that is attached to a single cable terminal located at the center of the head of the protection device. The single stem system generally includes some form of clip-in loop attached to the single cable. Single stem connection systems are generally preferable for larger cams because they are less likely to obstruct particular camming placements.
Small camming devices provide protection and/or support from a small protection surface. For most applications, small camming devices must support the same outward forces as larger camming devices. Therefore, in order to provide reliable protection, small camming devices should maximize the camming surface, which contacts the protection surface. This objective becomes more difficult the smaller the protection surface within which the device is designed to accommodate. For example, a camming device that is designed to fit into cracks between 0.1 and 0.2 inches should maximize the camming surfaces of the camming device more so than a camming device that is designed to fit into cracks between 1 and 2 inches. In addition, small camming devices are more likely to pop out of the protection surface from axle bending, inverted cam lobes, or uneven lateral stem bending. Therefore, small camming devices should minimize these affects to ensure reliable placements.
The present invention relates to an improved active camming device. In accordance with the present invention, a dual stem active camming device includes a plurality of compression springs independently coupled to the plurality of cam lobes. The compression springs are positioned between the trigger and the clip-in point of the cam to protect the springs from damage and allow the trigger to compress the springs upon retraction. In addition, a flexible stem tube is positioned over the portion of the dual stem between the trigger and the cable terminals. The flexible stem tube shields the trigger wires from debris and abrasion. A rigid yoke is also positioned over the dual stem between the stem tube and the cable terminals. The rigid yoke prevents uneven lateral bending on the head of the camming device that may otherwise cause the device to pull out of a placement. The cable terminals are positioned between the outer cam lobes and on either side of the inner cam lobe. Alternatively, a combination of compression springs and other springs could be used to actuate the cam lobes and remain consistent with the present invention. Likewise, any number of cam lobes may be used and remain consistent with the teachings of the present invention.
In one embodiment, the present invention includes a dual stem active camming device with three cam lobes. Two cable terminals are positioned between the outer two cam lobes and on either side of the middle cam lobe. The device includes a lower yoke, the inclusion of which results in requiring an increased force on the device before it will laterally bend in an undesired manner. The device also includes a flexible stem tube with at least one compliant spring. The stem tube shields the trigger wires that couple the three cam lobes to the springs and trigger. Three compression springs are positioned between the trigger and the clip-in-point on the device. The compression springs are independently coupled to the cam lobes. The compression springs are significantly protected from debris and interference by positioning them adjacent to the clip-in point. The compression springs bias the cam lobes in an open position. As the trigger is retracted, the pushers, independently coupled to the cam lobes via trigger wires, abut the compression springs allowing the cam lobes to be temporarily retracted.
In an alternative embodiment, the device includes two cam lobes positioned between the cable terminals. Two cam lobes devices are useful for fitting into small crevices that may not otherwise accommodate the width of a three or four cam lobe device. In the two cam lobe embodiment, only two springs are necessary for independent operation. Each of the cam lobes is coupled to one of the springs via one or more trigger wires. This alternative embodiment also includes a lower yoke, the inclusion of which results in requiring an increased force on the device before it will laterally bend in an undesired manner. The device includes a flexible stem tube with at least one compliant spring. The stem tube shields the trigger wires that couple the cam lobes to the springs and trigger. The two compression springs are positioned between the trigger and the clip-in-point on the device. The positioning of the compression springs adjacent to the clip-in point protects them from interference and debris. The compression springs bias the cam lobes in an open position. As the trigger is retracted, the pushers, independently coupled to the cam lobes via trigger wires, abut the compression springs allowing the cam lobes to be temporarily retracted.
In yet another alternative embodiment, the device includes four cam lobes. The cable terminals are positioned between the outer cam lobes and on either side of the two inner cam lobes. Four cam lobe devices provide additional stability in flaring or irregular shaped crevices because they provide additional connection points between the device and the camming surface. In this alternative embodiment, four springs are necessary to independently control the four cam lobes. However, coupling two or more cam lobes to the same spring would result in the use of fewer springs. For independent operation, each of the cam lobes is coupled to one of the springs via a trigger wire. This alternative embodiment also includes a lower yoke, the inclusion of which results in requiring an increased force on the device before it will laterally bend in an undesired manner. The device includes a flexible stem tube with at least one compliant spring. The stem tube shields the trigger wires that couple the four cam lobes to the springs and trigger. The four compression springs are positioned between the trigger and the clip-in-point on the device. The positioning of the compression springs adjacent to the clip-in point protects them from interference and debris. The compression springs bias the cam lobes in an open position. As the trigger is retracted, the pushers, independently coupled to the cam lobes via trigger wires, abut the compression springs allowing the cam lobes to be temporarily retracted.
The embodiments described above may also be combined. The foregoing and other features, utilities, and advantages of the invention will be apparent from the following detailed description of the invention with reference to the accompanying drawings.
The accompanying drawings illustrate various embodiments of the present invention and are a part of the specification. The illustrated embodiments are merely examples of the present invention and do not limit the scope of the invention.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.
Reference will now be made to the drawings to describe presently preferred embodiments of the invention. It is to be understood that the drawings are diagrammatic and schematic representations of the presently preferred embodiments, and are not limiting of the present invention, nor are they necessarily drawn to scale.
The present invention relates to an improved active camming device. In accordance with the present invention, a dual stem active camming device includes a plurality of compression springs independently coupled to the plurality of cam lobes. The compression springs are positioned between the trigger and the clip-in point of the cam to protect the springs from damage and allow the trigger to compress the springs upon retraction. In addition, a flexible stem tube is positioned over the portion of the dual stem between the trigger and the cable terminals. The flexible stem tube shields the trigger wires from debris and abrasion. A rigid yoke is also positioned over the dual stem between the stem tube and the cable terminals. The rigid yoke prevents uneven lateral bending on the head of the camming device that may otherwise cause the device to pull out of a placement. The cable terminals are positioned between the outer cam lobes and on either side of the inner cam lobe. Alternatively, a combination of compression springs and other springs could be used to actuate the cam lobes and remain consistent with the present invention. Likewise, any number of cam lobes may be used and remain consistent with the teachings of the present invention. Also, while embodiments of the present invention are described in the context of an improved dual stem active camming device, it will be appreciated that the teachings of the present invention are applicable to other applications as well. For example, the teachings of the present invention could also be applied to a single or triple stem active camming device.
Reference is initially made to
The retraction system is illustrated on the left portion of the
Disposed below the pusher sets are three springs 190, 200, 210. When the trigger 180 is retracted, it forces the pushers sets 185, 187, 195, 197, 205, 207 and consequently the trigger wires 220, 225, 230 onto the springs 190, 200, 210. Therefore, the cam lobes 115, 120, 125 are biased into an extended position because the springs 190, 200, 210 bias the pusher sets 185, 187, 195, 197, 205, 207 and the trigger wires 220, 225, 230. Alternatively, the compression springs 190, 200, 210 and the trigger wires 220, 225, 230 could be single units. Meaning that each compression spring is wound out of the same wire as the respective trigger wire. This alternative arrangement would eliminate the need to couple the trigger wires and the compressions springs and possibly allow them to be replaceable. The retraction system will be further explained with reference to
The connection system is illustrated throughout
Reference is next made to
The process for coupling the trigger wire 220 to the pusher sets 185, 187, includes multiple steps. The male and female pusher portions 187, 185 are disposed on the cable 150 between the springs 190 and the trigger 180. The head portion 222 of the trigger wire 220 is routed through the opening in the female pusher portion 185. The head portion 222 is then slotted into a slot or groove on the female pusher portion 185 such that the trigger wire does not interfere with the cable and vice versa. The male and female pusher portions 187, 185 are properly oriented to interlock with one another. The male and female pusher portions 187, 185 are rotationally keyed to require a specific rotational orientation with respect to one another. The male and female pusher portions 187, 185 are then pushed together. In operation, the spring 190 (seen in
Reference is next made to
It will also be appreciated that the trigger 180 is shaped in a manner to conceal and protect the pusher sets 185, 187, 195, 197, 205, 207 (not visible in
It will also be appreciated that the lower yoke 160 operates to minimize lateral bending and protect the overall integrity of the device 100. Many small camming devices fail in vertical placements when the cable is allowed to laterally bend beyond a particular angle. The lower yokes 160 interconnect the two portions of the cable 150 in a rigid manner to transfer any lateral bending moments onto both cable terminals 135, 140. By transferring the lateral bending forces between the two cable terminals 135, 140, the device is able to withstand additional bending force before it rips out of a placement. In addition, the flexibility of the stem tube 165, allows the cable 150 to bend, thereby transferring the bending force onto the lower yoke 160 where it is distributed between the two cable terminals 135, 140. Therefore, the inclusion of the stem tube 165 and the lower yoke 160 on any dual stem active camming device will result in requiring an even greater force for undesirable lateral bending to occur.
It will also be appreciated that the positioning of the cable terminals 135, 140 between the outer cam lobes 115, 125 and on either side of the inner cam lobe 120 minimizes the possibility of axle bending. Another reason camming devices fail is when the axle that interconnects the cam lobes is allowed to bend. Axles bend around the cam lobes as a result of the force exerted upon them at the point at which the axle is coupled to the cable terminals. Therefore, the distance from any one cam lobe to the nearest cable terminal, along the axle, effectively forms a moment arm. To maximize the force required to bend the axle around the cam lobe, the moment arm distance must be minimized. In the illustrated embodiments of
Reference is next made to
Reference is next made to
Reference is next made to
Reference is next made to
While this invention has been described with reference to certain specific embodiments and examples, it will be recognized by those skilled in the art that many variations are possible without departing from the scope and spirit of this invention. For example, the teachings of one embodiment may be combined with the teachings of another and remain consistent with the scope and spirit of this invention. The invention, as defined by the claims, is intended to cover all changes and modifications of the invention which do not depart from the spirit of the invention. The words “including” and “having,” as used in the specification, including the claims, shall have the same meaning as the word “comprising.”
This application claims priority to U.S. Provisional Application Ser. No. 60/538,413 filed Jan. 22, 2004, entitled “ACTIVE CAMMING DEVICE”.
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