EP3302731A1

EP3302731A1 - Camming device

Info

Publication number: EP3302731A1
Application number: EP15728483.7A
Authority: EP
Inventors: James Wilson
Original assignee: Wild Country Ltd
Current assignee: Wild Country Ltd
Priority date: 2015-06-05
Filing date: 2015-06-05
Publication date: 2018-04-11
Also published as: WO2016192811A1

Abstract

A camming device (10) comprises a first camming lobe (12), a second camming lobe (14), a bearing portion (16) pivotally carrying the first camming lobe (12) and the second camming lobe (14) at at least one pivot axle, a load portion (22) having securing means (24) for securing the camming device (10) to other safety equipment, and a stem portion (26) extending between the bearing portion (16) and the load portion (22).

Description

Camming Device Description

The present invention provides a camming device comprising a first camming lobe a second camming lobe, a bearing portion pivotally carrying the first camming lobe and the second camming lobe at at least one pivot axle, a load portion having securing means for securing the camming device to other safety equipment, and a stem portion extending between the bearing portion and load portion.

A camming device of this type is known as part of conventional climbing equipment for rock-climbing, ice-climbing or any other type of climbing and allows the climber to establish an anchor point at a crack or a pocket in the rock by inserting the camming lobes into the crack or pocket and attaching a climbing rope to the load portion of the device via a sling and a carabiner. The load portion is connected to the bearing portion by virtue of the stem portion in such a way as to force the camming lobes to spread further apart into clamping and pressing contact with the opposite walls of the crack or pocket when a pulling force is applied to the load portion such as in the event of a fall. Alternatively, the climber may use the camming device to

temporarily support his/her weight at such anchor point by connecting the load portion with a hip belt of the climber or there like.

One disadvantage of conventional camming devices having multiple camming lobes is their considerable weight mainly caused by the weight of the camming lobes and the bearing portion. In particular, as the working principle of such devices rely upon large leverage forces occurring when a pulling force applied at the load portion is transmitted into rotational forces at the camming lobes, the bearing portion and the pivot axle have to be provided with sufficient stability and mechanical resistance in order to reliably transmit such forces between the bearing portion and the camming lobes. Therefore, the bearing portion, the pivot axle as well as the camming lobes are conventionally made from solid steel material of sufficient strength which is responsible for a relatively high minimum weight of the camming device.

Under the above-described circumstances it was an object of the present invention to provide an improved camming device which has a higher stability and reliability for protecting a climber against the consequences of a fall, and which also has a high usability for the climber, in particular a low weight.

According to the present invention, this object is achieved by a camming device comprising a first camming lobe, a second camming lobe, a bearing portion pivotally carrying the first camming lobe and the second camming lobe at at least one pivot axle, a load portion having securing means for securing the camming device to other safety equipment, and a stem portion extending between the bearing portion and load portion, wherein the at least one pivot axle includes a hollow portion.

Taking into account the crucial role the bearing portion plays for the stability and the reliability for the camming device it was not obvious for a person skilled in the art to provide any hollow portions in the pivot axle and thus to apparently structurally weaken the pivot axle. Rather, a person skilled in the art would have conceived alternative materials or smaller dimensions of the entire device when being confronted with the technical problem of reducing the weight of the camming device. However, the inventors of the present invention have attacked this prejudice and found the surprising result that a weight reduction of the camming device by providing a hollow portion within the pivot axle can be achieved without a significant reduction of the mechanical stability of the device. The resulting camming device has high mechanical resistance and long-term stability and, simultaneously, a low weight.

Preferably, said bearing portion has a connecting plate, wherein said pivot axle having the hollow portion has at least one end portion connected to the connecting plate such that a mechanically simple and stable structure is provided. In such embodiment the hollow portion provided in the pivot axle may extend through said end portion connected to the connecting plate. This configuration allows the weight reduction achieved according to the present invention to be maximized. It was particularly non-obvious to allow the hollow portion to extend through said end portion, since the end portion is bearing most of the load including shearing forces during use. However, the inventors of the present invention have found that such forces can be conveniently distributed through the tubular material surrounding the hollow portion even at the end portion connected to the connecting plate.

In a preferred embodiment the above-described hollow end portion passes through a hole in the connecting plate and is deformed or crimped to lock with the connecting plate at a rim portion of the hole. Such deformation or crimping allows an easy and reliable fixation between the axle and the connecting plate using a minimum number of elements. In particular, any screwing connection can be avoided. Furthermore, it has been found that a deformation or crimp lock connection of this type advantageously increases the stability of the axle at the end portion due to a local increase of the diameter and the wall thickness of the axle at the end portion. Therefore, the formation of the end portion as a hollow portion provides an advantageous double effect by lightening the axle on the one hand and allowing easy and effective deformation or crimp lock connection on the other hand.

In an embodiment as described above where a hollow end portion of the pivot axle is deformed or crimped to lock with the connecting plate at a rim portion of the hole, said rim portion may have a circumferential chamfer abutting the deformed or crimped end portion of the pivot axle. Because of this chamfer the surface between the axle and the connecting plate is increased significantly which allows forces input to the connection between the axle and the connecting plate (such as forces transverse to the pivot axle occurring during use of the device) to be distributed over a larger area.

Accordingly, stability and mechanical resistance even under a load can be increased. ln a further embodiment of the present invention the pivot axle which has a hollow portion may have at least one solid end portion. In other words, at least one end portion of the pivot axle may be non-hollow or solid, whereas a different axle portion of the pivot axle includes the hollow portion. In the same way as described earlier for the hollow end portion, at least one solid end portion may be connected to a connecting plate of the bearing portion. In particular, the solid end portion may pass through a hole in the connecting plate. In such hole the solid end portion may be connected to the connecting plate through a riveted connection, press fitting connection, screwing connection or any other suitable type of connection. Providing a pivot axle with a hollow portion and a solid end portion combines the advantage of a solid axle with respect to stability and integrity and the advantage of reduced weight of a hollow axle.

In a preferred embodiment of the present invention the pivot axle has two solid end portions and a hollow portion encapsulated between the solid end portions. Such pivot axle can preferably be manufactured by a manufacturing process comprising the steps of:

- providing a first axle portion having a solid end portion on its one end and a hollow end portion at its opposite end,

- providing a second axle portion having a solid end portion at its one end and a hollow end portion at its opposite end,

- coaxially connecting the first axle portion and the second axle portion by connecting the hollow end portions to one another.

Preferably, the step of connecting the hollow end portions of the first and the second axle portions includes a step of welding or friction welding such as to obtain a long-lasting and stable fixation. The step of connecting the hollow end portions, in particular by a welding operation, may be followed by a step of machining the connection portion, in particular the welded joint portion, such as to remove unwanted flash of the weld or any ridge and to achieve a flat tubular outer surface of the pivot axle. ln a camming device according to a further embodiment the bearing portion may comprise a first pivot axle and a second pivot axle, wherein each of the first and second pivot axle includes a hollow portion. A camming device having two pivot axles has a higher reliability and improved usability due to a more effective leverage of the camming lobes. The first pivot axle and the second pivot axle may be positioned parallel to one another, wherein the first end portion of the first pivot axle and the first end portion of the second pivot axle may be connected to a common first connecting plate and furthermore, a second end portion of the first pivot axle and a second end portion of the second pivot axle may be connected to a common second connecting plate. The resulting structure having two axles and two connecting plates each mounted parallel to one another provides a stable frame structure for bearing the camming lobes.

One or more of the above-described features contributing to an increased stability of the device allow the pivot axle having the hollow portion being made of a light alloy metal in preferred embodiments of the invention, such that an additional reduction of the overall weight can be achieved.

The present invention is further illustrated by the following description of preferred embodiments shown in the attached drawings. In particular, figure 1 shows an explosion view of a camming device according to a first embodiment of the present invention, figure 2 shows an assembled view of the camming device of the first embodiment, figures 3a and 3b show the camming device of the first embodiment in a fully closed position in a side view and in a cross-sectional view according to line B-B, respectively, figures 4a and 4b show the camming device of the first embodiment in a fully opened position in a side view and in a cross-sectional view according to a line A-A, respectively, figures 5a to 5c show a perspective view, a front view and a top view of a bearing portion of the camming of the first embodiment, figure 6a shows a perspective view of a pivot axle of the camming device of the first embodiment, figure 6b shows a front view of the pivot axle of figure 6a, figure 6c shows a cross-sectional view according to line A-A in figure 6b, figure 7a shows a front view of a connecting plate of the camming device of the first embodiment, figure 7b shows a cross-sectional view according to a cross section B-B in figure 7a, figure 8a shows a side view of the bearing portion shown in figure 5a, figure 8b shows a cross-sectional view of the bearing portion according to a cross section C-C in figure 8a, figure 8c shows an enlarged view of an area D in figure 8b, figure 9a shows a side view of a pivot axle which is part of a camming device configured according to a second embodiment of the present invention, figure 9b shows a cross-sectional view according to cross section A-A in figure 9a, and figures 10a and 10b show a side view and a cross-sectional view of a first pivot axle portion used to manufacture a pivot axle as shown in figure 9a and 9b.

With reference to figures 1 to 4b, the general construction of a camming device according to a first embodiment of the present invention will be described below. A camming device 10 of the first embodiment comprises at least one first camming lobe 12 (for example two first camming lobes 12), at least one second camming lobe 14 (for example two second camming lobes 14), a bearing portion 16 pivotally carrying the first and second camming lobes 12, 14 on at least one pivot axle 8, 20, a load portion 22 having securing means such as a sling portion 22 for securing the camming device 10 to any other safety equipment such as a safety rope by means of a carabiner, for example, and further comprises a stem portion 26 which extends between the bearing portion 16 and the load portion 22.

Camming lobes 12, 14 have a bearing holes 28, 29 at which they are pivotally mounted to at least one pivot axle 8, 20, and further have camming surfaces 30, 31 adapted to frictionally engage the wall of a crack or a hole inside a rock. In the present embodiment, for example, the bearing portion 16 comprises two pivot axles, a first pivot axle 18 carrying the first camming lobes 12 at their respective bearing holes 28 and a second pivot axle 20 carrying the second camming lobes 14 at their respective bearing holes 29. Furthermore, the first camming lobes 12 each have a passing hole 32 positioned between the bearing hole 28 and the camming surface 30, said passing hole 32 being enlarged to allow a free passage of the second pivot axle 20, such that the first camming lobe 12 is free to pivot about the first pivot axle 18 within an angular range of about 70 to 1 10° according to the inner size of the passing hole 32. Likewise, the second camming lobes 14 each have a passing hole 34 positioned between the bearing hole 29 and the camming surface 31 , said passing hole 34 being enlarged to allow a free passage of the first pivot axle 18, wherein the size of the passing hole 34 is large enough to allow a free pivoting movement of the second camming lobe 14 about the second pivot axle 20 within a predetermined angular range between about 70 to 100°. Moreover, as can be seen in Fig. 1 , in the illustrated example two first camming lobes 12 are provided adjacent to one another, which are sandwiched between two second camming lobes 14.

Regardless of whether the bearing portion 16 comprises only one pivot axle or two pivot axles 18, 20, the first and second camming lobes 12, 14 are pivotally coupled to the bearing portion 16 such as to be movable between an open position in which the camming surfaces 30, 31 of the first and second lobes 2, 14 are spread apart in order to contact and press against the walls of a crack or a hole in the rock, and a closed position in which the camming surfaces 30, 31 are approached to one another in order to allow the camming device 10 to be inserted into the crack or hole or to be removed from the crack or hole. The fully opened position is illustrated in figures 4a and 4b, whereas a fully closed position is illustrated in figures 3a and 3b.

The pivoting movement of the camming lobes 12, 14 between the open position and the closed position is governed by at least one spring 36 arranged to bias the camming lobes 12, 14 into the open position. For example, a first spring 36 may be provided between a first camming lobe 12 and an adjacent second camming lobe 14 in order to bias the camming lobes in opposite rotational directions. In the example shown in the figures of the present embodiment, spring 36 is a double torsion spring wherein one portion of the spring 36 is wound around the first pivot axle 18 and engages one of the first and second camming lobes 12, 14, wherein another portion of the spring 36 is wound around the second pivot axle 20 and biases the other one of the first and second camming lobes 12, 14.

The camming device may further comprise a trigger 38 that can be manually operated by the user to rotate the camming lobes 12, 14 against the biasing force of the spring 36 from the open position towards the closed position. Trigger 38 preferably includes a finger grip 40 which is slidably mounted to the stem portion 26 such as to be movable along the axis of the stem portion 26. Trigger wires 42 (only partially illustrated in figures 1 and 2) may be used to connect trigger 38 with the first and second camming lobes 12, 14 such that pulling the finger grip 40 along the axis of the stem portion 26 in a direction away from the bearing portion 16 will rotate the camming lobes against the biasing force of the spring 36 towards the closed position (see figures 3a and 3b). Upon releasing the force to the finger grip 40 the biasing force of spring 36 will rotate camming lobes 12, 14 back to their open position (figures 4a and 4b). For a convenient one-hand operation during use, the sling portion 24 may be configured with a thumb grip 44 against which a user's thumb passed through the sling portion 24 may rest. An actuation of the trigger 38 to move the camming device 10 from the open position towards the closed position can then be carried out in a similar manner as operating a syringe by sliding finger grip 40 with two fingers towards the load portion 22 and applying a counterforce to the load portion 22 by the thumb pressing against the thumb grip 44. In the closed position the camming device 10 may be inserted into the crack or hole of the particular wall feature. After releasing the force applied by the user's fingers and thumb spring 36 will drive the camming lobes 12, 14 towards the open position into contact with the inner walls of the crack or hole.

In a use condition, any force applied to the camming device 10 through the load portion 22, in particular, any pulling force applied at the sling portion 24, further pulls the bearing portion 16 and thus at least one pivot axle 18, 20 further in a direction of spreading cam lobes 12, 14 (towards the open position of the camming device 10), such that the camming surfaces 30, 31 will be pressed with increasing force towards the walls of the crack or hole. The higher the pulling force at load portion 22 the larger will be pressing force of the camming surfaces 30, 31 and thus the friction between the camming surfaces 30, 31 and the walls, thus achieving a secure connection between the camming device 10 and the rock or ice.

For removing the camming device 10 from the crack or hole after use, the trigger 38 may be actuated in the same manner as described above to move the camming device 10 towards the closed position, to release the camming lobes 12, 14 from the contact with the walls and to then pull out the camming device 10.

With reference to figures 5a to 8b a configuration of the bearing portion 6 according to the first embodiment of the present invention will be described in the following.

Bearing portion 16 according to the present embodiment comprises the first and second pivot axles 18, 20 arranged parallel to one another, a first connecting plate 46 to which first ends of the pivot axles 18, 20 are connected, and a second connecting plate 48 to which the other ends of the pivot axles 18, 20 are connected, respectively. Each connecting plate 46, 48 has at least two holes 50, 52 for receiving respective ends of pivot axles 18, 20. Furthermore, the first and/or second connecting plate 46, 48 may further comprise a third hole 54 provided to reduce the weight of the connecting plate 46, 48.

As can be seen in figure 1 , in the assembled state of the camming device 10 all camming lobes 12, 14 as well as the at least one spring 36 are fitted to the pivot axles 18, 20 and sandwiched between the connecting plates 46, 48.

At least one of the pivot axles 18, 20, preferably both pivot axles 18, 20, include a hollow portion 56. As can be seen in figure 6c, first pivot axle 18 is formed as a hollow cylindrical tube with a hollow portion 56 extending along the entire axial length of the first pivot axle 8. The second pivot axles 20 is preferably formed as a hollow cylindrical tube as well.

In the following, a connection between the pivot axles 18, 20 and the connecting plates 46, 48 will be described taking the connection between the first pivot axle 18 and the first connecting plate 46 as example. The connection principles as described below can be applied in the same manner also to the other connections between pivot axles 18, 20 and connecting plates 46 and 48. An end portion 58 of the first pivot axle 18 passes through the hole 50 in the first connecting plate 46 and slightly protrudes from the opposite side of the connecting plate 46. The protruding end 58 is deformed or crimped outwardly such as to lock at an outer rim portion 60 of hole 50. Any conventionally known punching or crimping tool, for example a riveting tool, may be used to establish such form-fit connection.

As can be seen in the enlarged illustration in figure 8c, the outer rim portion 60 of hole 50 may be formed with an outwardly facing, inclined chamfer 62, i. e. imparting a shape of a frustum of a cone to the outer rim portion 60.

Chamfer 62 reduces the impact of shearing forces that may apply to the connection portion between the first pivot axle 18 and the first connecting plate 46 at the outer rim portion 60 by increasing a surface of contact between the deformed or crimped material of the end portion 56 and the connecting plate 46. In such way the chamfer 62 makes a contribution to compensating any loss in stability and mechanical resistance brought about by the hollow configuration of the first axle 18.

As can be further seen in figures 6a to 6c, the end portion 56 which is to be connected to connecting plate 46 may be formed with a reduced diameter as compared to inner portions of the first pivot axle 18 such that a step 64 is formed at which an inner rim portion 66 of hole 50 abuts in the assembled state. Thus, as can be seen in figure 8c, the connecting plate 46 can be sandwiched and clamped at its rim portions 60, 66 between the deformed end portion 58 and the step 64.

Figure 9a and 9b show a second embodiment of the present invention, which is a modification of the first embodiment described with respect to figures 1 to 8c. Thus, only features in which the second embodiment differs from thefirst embodiment will be described in the following and reference is made to the detailed description of the first embodiment above as regards all other structural and functional features. A pivot axle 18a of a camming device according to the second embodiment may include a hollow portion 56a extending in an axial middle portion of the first pivot axle 18a, whereas an end portion 58a, preferably both opposite end portions of the pivot axle 18a, is formed as a solid end portion. Thus, the hollow portion 56a does not extend into or through the end portion 58a. The first pivot axle 18a may be connected to a connecting plate by inserting the solid end portion 58a into a hole of the connecting plate and establishing a riveted connection between the end portion 58a and the connecting plate. Alternative ways of connection, such as a press fitting connection or a screw connection are conceivable.

A pivot axle 18a having two opposite solid end portions 58a and a hollow portion 56a encapsulated inside the pivot axle 18a between the end portions 58a can preferably be manufactured by coaxially connecting two pivot axle portions or halve axles 70a, one of which being shown in figures 10a and 10b. Pivot axle portion 70a comprises a solid end portion 58a and a hollow end portion 72a in other words, the axle portion 70a is formed as a sleeve having an open end 72a and a closed end 58a. In order to manufacture the pivot axle 18a two axle portions 70a of the type as shown in figures 10a and 10b may be connected coaxially by joining their respective hollow end portions 72a such that the hollow end portions 72a form the hollow portion 56a encapsulated inside the pivot axle 18a as seen in figures 9a and 9b. The connection may be established by welding, in particular friction welding. A joint portion or a seaming portion 74 may be machined or otherwise treated in order to remove ridges or flash of the weld.

Since the solid end portion 58a is less prone to breaking due to shearing forces or other forces transverse to the axial direction of the pivot axle 18a during use, the second embodiment may have advantages with regard to stability and mechanical resistance while still achieving significant weight reduction due to the hollow portion 56a. The solid end portion 58a may be manufactured with a reduced outer diameter as compared to the central portion of the pivot axle 18a such that a step 64a is formed at which an inner rim portion 66 of hole 50 may abut in the assembled state.

As described also for the first embodiment, the configuration of the first pivot axle 18a of the second embodiment and its connection to a connecting plate can be applied to a second pivot axle to achieve the corresponding advantages.

Claims

A camming device (10) comprising

a first camming lobe (12),

a second camming lobe (14),

a bearing portion (16) pivotally carrying the first camming lobe (12) and the second camming lobe (14) at at least one pivot axle (18, 20; 18a),

a load portion (22) having securing means (24) for securing the camming device to other safety equipment, and

a stem portion (26) extending between the bearing portion (16) and the load portion (22),

characterized in that at least one pivot axle (18, 20; 18a) includes a hollow portion (56; 56a).

A camming device (10) according to claim 1 , characterized in that the bearing portion (16) has a connecting plate (46, 48), wherein said pivot axle (18, 20; 18a) has at least one end portion (58; 58a) connected to the connecting plate (46, 48)

A camming device (10) according to claim 2, characterized in that the hollow portion (56) extends through said end portion (58) connected to the connecting plate (46, 48).

A camming device (10) according to claim 2 or claim 3, characterized in that said end portion (58; 58a) passes through a hole (50,52) in the connecting plate (46, 48) and is deformed or crimped to lock with the connecting plate (46, 48) at a rim portion (60) of the hole (50, 52).

A camming device (10) according to claim 4, characterized in that said rim portion (60) has a circumferential chamfer (62) abutting the deformed or crimped end portion (58; 58a) of the pivot axle (18).

6. A camming device (10) according to any of the preceding claims, characterized in that said hollow portion (56) extends through the entire length of the pivot axle (18)

A camming device according to any of claims 1 to 5, characterized in that said pivot axle (18a) has at least one solid end portion (58a).

A camming device according to claim 7, characterized in that said bearing portion (16) has a connecting plate, wherein said pivot axle (18a) has at least one solid end portion (58a) connected to the connecting plate.

A camming device according to claim 7 or claim 8, characterized in that the pivot axle 18a is formed from a first pivot axle portion 70a and a second pivot axle portion 70a, each pivot axle portion having a solid end portion 58a and a hollow end portion 72a, wherein the two pivot axle portions 70a are coaxially connected to one another at their respective hollow end portion 72a, the connection preferably being formed by welding or friction welding.

A camming device (10) according to any of the preceding claims, characterized in that the bearing portion (16) comprises a first pivot axle (18; 18a) and a second pivot axle (20), wherein each of the first and second pivot axles (18, 20; 18a) includes a hollow portion (56; 56a).

1 1 . A camming device (10) according to claim 10, characterized in that the first pivot axle (18; 18a) and the second pivot axle (20) are positioned parallel to one another,

o wherein a first end portion of the first pivot axle (18; 18a) and a first end portion of the second pivot axle (20) are connected to a common first connecting plate (46), and wherein, preferably a second end portion of the first pivot axle (18; 18a) and a second end portion of the second pivot axle (20) are connected to a common second connecting plate (48). 12. A camming device (10) according to any of the preceding claims, characterized in that the pivot axle (18, 20; 18a) is made of a light alloy metal.