EP3496820B1

EP3496820B1 - A device for stopping a fall during climbing or descending along a rope

Info

Publication number: EP3496820B1
Application number: EP17717251.7A
Authority: EP
Inventors: VAN DEN Peter HERIK
Original assignee: XSPlatforms BV
Current assignee: XSPlatforms BV
Priority date: 2016-02-05
Filing date: 2017-02-01
Publication date: 2021-04-07
Anticipated expiration: 2037-02-01
Also published as: NL2016911B1; NL2016911A; EP3496820A1

Description

Field of the invention

The invention relates to a fall arrest device (fall arrester) for stopping a fall during ascending or descending action along a cable, comprising:

two oblong clamp portions which are spaced apart from each other and which during operation are present on either one of the two sides of the cable and slide over the cable, where each of these clamp portions is provided with a clamp surface, which clamp surfaces are located opposite each other and are facing each other, and where each of the clamp portions has two ends seen in longitudinal direction,
two connecting arms which are spaced apart from each other seen in longitudinal direction of the clamp portions, where one of the ends of each clamp portion is hingedly connected to each of the connecting arms, and
a coupling element to which a carabiner can be affixed and which is hingedly connected to one of the ends of each of the connecting arms while the other end is connected to the other connecting arm.

Position of the art

US1117874A discloses a device according to the preamble of claim 1. This known device is a wire gripping device having wire engaging bar members and lever plates fulerumed on the lower bar member at each end at each side thereof, and having a pivotal engagement with the other bar member at the upper end and a pull bar pivotally connected to the lower end of the lever plates. This wire gripping device can be quickly placed on a wire at any point to provide a firm grip, without fear of injuring the wire, to which grip the wire tightening apparatus may be attached.
Further, from US2012279020A a device for fastening and clamping straps is known. In order to create a device for fastening and clamping straps that also permanently withstands high mechanical loads of the type that occur during the tensioning of slacklines, a pair of pivoting levers are provided, between which two mutually parallel clamping plates with flat clamping surfaces are hinged, the clamping surfaces being at least as wide as the strap and being provided with means for securing the strap in the clamped state. The pivoting levers are fastened to a tensioning device, on actuation of which the pivoting levers absorb the tension and transmit it to the clamping plates so that the clamping surfaces of the clamping plates are pressed together, thereby securely clamping the strap fitted between the clamping surfaces.

Summary of the invention

It is an object of the invention to provide a fall arrest device of the type defined in the opening paragraph which is simple, robust and reliable. For this purpose the fall arrest device according to the invention is characterized in that the fall arrest device further includes a pawl which is located on the coupling element and can pivot around a pivot shaft and is pivotally connected to the coupling element between said first ends of the connecting arms, which pawl has a free end which can be moved between:

an up/down position in which the clamp portions slightly press against the cable and the fall arrest device cannot be disengaged from the cable, and in which the pawl prevents an up movement of the coupling element relative to the clamp portions when the fall arrest device is situated on a cable,
a clamp position in which the clamp portions firmly press against the cable, and
a release position in which the pawl allows of an upward movement of the coupling element relative to the clamp portions in the event of the presence of the fall arrest device on a cable, so that the fall arrest device can be disengaged from the cable.

The purpose of this pawl is to prevent the clamp portions from moving away from each other and ending in the release position when the user ascends, in which release position the fall arrest device can be disengaged from the cable. When the user wishes to disengage the fall arrest device from the cable he/she is to push the pawl away.
Preferably, the clamp portions run parallel to each other and the clamp surfaces are oblong and also run parallel to each other.
An embodiment of the fall arrest device according to the invention is characterized in that the hinge points of the clamp portions with one of the connecting arms, seen in longitudinal direction of the cable situated between the clamp portions during operation, are spaced apart from each other, where the lower of the two hinge points is located between the two ends of the connecting arm and the first connecting arm end connected to the coupling element is located on the same side of the cable as this lower hinge point, so that, in the event of a downward movement of the coupling element relative to clamp portions, the clamp surfaces are moved towards each other, and in the event of an upward movement of the coupling element relative to clamp portions, the clamp surfaces are moved away from each other.
Preferably, the fall arrest device comprises a spring that pushes the pawl to the clamp position. This spring provides that the pawl retracts to the original position (clamp position) when it is released. The spring additionally provides that in the clamp position the cable is (slightly) squeezed as a result of which the user, in the event of a fall, draws up the fall arrest device and the braking mechanism can start operating.
Yet a further embodiment of the fall arrest device according to the invention is characterized in that the pawl is provided with a pin that can be moved in a curved groove provided in the coupling element when the pawl is rotated between the clamp position and release position, and in that the coupling element comprises a blocking element which, when the fall arrest device is engaged with a cable upside down, fits in the groove under the influence of gravity and prevents the pin from moving through the groove and thus blocks the pawl. This pin is to provide that the clamp portions cannot change to the release position when the fall arrest device is placed on the cable in an upside down position. Gravity as well as the freedom of movement of this pin provide that the pawl in this position is blocked against rotation and as a result the clamp portions cannot be moved away from each other.

Brief description of the drawings

The invention will be further explained below while reference is made to an example of embodiment of the fall arrest device (fall arrester) according to the invention shown in the appended drawings, in which:

Fig. 1 shows a side view of an embodiment of the fall arrest device according to the invention;
Fig. 2A shows a bottom view of the fall arrest device shown in Fig. 1;
Fig. 2B shows a detailed view of differently arranged clamp surfaces;
Fig. 3 shows a perspective view of the fall arrest device shown in Fig. 1;
Fig. 4 shows the fall arrest device in the move position;
Fig. 5 shows the fall arrest device in the clamp position;
Fig. 6 shows the fall arrest device in the release position;
Fig. 7 shows the fall arrest device upside down in the move position;
Fig. 8 shows a detailed view of Fig. 7 at the location of the blocking element;
Fig. 9 shows the fall arrest device upside down in the release position; and
Fig. 10 shows a detailed view of Fig. 9 at the location of the blocking element.

Detailed description of the drawings

Figs. 1, 2A and 3 show various views of an invented embodiment of the fall arrest device (fall arrester) for stopping a fall during ascending or descending action along a cable when the device is in engagement with a cable. The fall arrest device 1 comprises two oblong clamp portions 5 and 7 which run parallel to each other and are spaced apart from each other and which during use are located on either one of the two sides of the cable 3 and slide over the cable. Each of these clamp portions has an elongated clamp surface 6 and 8 which also run parallel to each other. These clamp surfaces are situated opposite each other and are facing each other. The fall arrest device 1 further includes two connecting arms 9 and 11 spaced apart from each other connecting the clamp portions 5 and 7 to each other and to a coupling element 13. Each clamp portion 5 and 7 with an end 5a and 7a is hingedly connected to the connecting arm 9 and with the other end 5b, 7b to the other connecting arm 11, while the coupling element 13 is hingedly connected to an end 9a, 11a of each of the connecting arms. A carabiner 15 may be affixed to the coupling element 13.
The two hinge points 17 and 19, 21 and 23 respectively of each of the clamp portions 5 and 7 with one of the connecting arms 9 and 11 are located at a distance 20 from each other seen in longitudinal direction of the cable 3. The lower one of the two hinge points 19 and 23 respectively is located between the two ends 9a and 9b and 11a and 11b respectively of the connecting arm 9 and 11 and the first coupling-element-connected end 9a, 11a respectively of the connecting arm is located on the same side of the cable 3 as the lower hinge point 19, 23 respectively. In the event of a downward movement of the coupling element 13 relative to the clamp portions 5 and 7, the clamp surfaces 6 and 8 will move towards each other as a result of this geometry and in the event of an upward movement of the coupling element 13 relative to clamp portions 5 and 7 the clamp surfaces 6 and 8 will move away from each other.
The clamp surfaces 6 and 8 are smooth curved planes. For increasing the grip on the cable 3 these clamp surfaces may also be arranged as straight planes. This is represented in Fig. 2B in which the clamp surfaces 6' and 8' of an alternative fall arrest device 1' are arranged as having a V-shaped cross section. The clamp surfaces may also be roughened or provided with teeth for increasing the grip on the cable.
The fall arrest device further includes a pawl 25 which can be pivoted around a pivot shaft 27 which is located between the first ends 9a and 11a of the connecting arms 9 and 11 on the coupling element 13. The purpose of this pawl is to avoid that during the ascending operation the clamp portions can move away from each other and end up in the release position in which the fall arrest device may be disengaged from the cable. When the user wishes to disengage the fall arrest device from the cable he/she is to push the pawl away. A torsion spring 29 provides that the pawl 25 is retracted to the original position when it is let go of. In addition, the torsion spring provides that when in the clamp position the cable is (slightly) clamped, so that the user, in the event of a fall, takes in the fall arrest device, and the braking principle is rendered operative.
For a further clarification of the operation of the fall arrest device as well as the pawl, Figs. 4, 5 and 6 show the fall arrest device in clamp position, move position and release position respectively. In the move position A (Fig. 4) the clamp portions 5 and 7 are slightly pressed against the cable 3 in that the pawl 25, due to the presence of the torsion spring 29, presses with a free end 25a against the clamp portion 7. In this position the pawl 25 imparts an upward movement of the coupling element 13 relative to the clamp portions 5 and 7, so that the fall arrest device 1 cannot be disengaged from the cable 3. For pressing the clamp portions more firmly against the cable an additional torsion spring 30 (see Fig. 4) may be installed, for example around hinge point 19 (or for example around hinge point 23) which torsion spring with one end rests against clamp portion 7 and with the other end against connecting arm 9. In the clamp position B (Fig. 5) the clamp portions 5 and 7 firmly press against the cable 3. This position is occupied in the event of a fall of the user who is connected to the coupling element 13 by means of a carabiner. As a result of the fall the coupling element 13 is pulled downward and the two clamp portions are pushed towards each other. In the release position C (Fig. 6) the pawl 25 allows of an upward movement of the coupling element 13 relative to the clamp portions 5 and 7, so that the fall arrest device can be disengaged from the cable. This release position cannot be occupied until the pawl 25 is manually pulled into the position represented in Fig. 6 against the spring force.
To the pawl 25 is affixed a pin 31 hat provides that the clamp portions cannot click to the release position if the fall arrest device is placed upside down on the cable. This is illustrated while reference is made to Figs. 7 and 9 in which the fall arrest device is represented upside down in the release state and move state respectively. Figs. 8 and 10 give detailed representations of this at the location of this pin 31. During the rotation of the pawl 25 between the clamp state B and the release state C the pin 31 can be moved in a curved groove 33 which is present in the coupling element 13. In the middle of the side wall of the curved groove 33 there is a recess 34 which accommodates a blocking element 35. If the fall arrest device is placed upside down on a cable, the blocking element 35 will drop from the recess 34 into the groove 33 owing to gravity and thus block the moving of the pin 31 through the groove and thus a rotation of the pawl 25. As a result, the coupling element 13 cannot be moved relative to the two clamp portions 5 and 7 so that, in consequence, the clamp portions can neither be moved towards each other nor away from each other.
Although the invention has been described in the foregoing based on the drawings, it should be observed that the invention is not by any manner or means restricted to the embodiment shown in the drawings. The invention also extends to all embodiments deviating from the embodiment shown in the drawings within the scope defined by the claims.

Claims

A fall arrest device (1) for stopping a fall during ascending or descending action along a cable (3), comprising:
- two oblong clamp portions (5, 7) which are spaced apart from each other and which during operation are present on either one of the two sides of the cable and slide over the cable, where each of these clamp portions is provided with a clamp surface, which clamp surfaces (6, 8) are located opposite each other and are facing each other and where each of the clamp portions has two ends (9a, 11a) seen in longitudinal direction,

- two connecting arms (9, 11) which are spaced apart from each other seen in longitudinal direction of the clamp portions, where one of the ends (5a, 7a) of each clamp portion is hingedly connected to each of the connecting arms, and

- a coupling element (13) to which a carabiner (15) can be affixed and which is hingedly connected to one of the ends (9a, 11a) of each of the connecting arms while the other end (5b, 7b) is connected to the other connecting arm (11),
characterized in that the fall arrest device further includes a pawl (25) which is located on the coupling element (13) and can pivot around a pivot shaft (27) and is pivotally connected to the coupling element (13) between said first ends (9a, 11a) of the connecting arms (9, 11), which pawl (25) has a free end (25a) which can be moved between:
- an up/down position (A) in which the clamp portions (5, 7) slightly press against the cable (3) and the fall arrest device (1) cannot be disengaged from the cable (3), and in which the pawl (25) prevents an upward movement of the coupling element (13) relative to the clamp portions (5, 7) in the event of the presence of the fall arrest device (1) on a cable (3),

- a clamp position (B) in which the clamp portions (5, 7) firmly press against the cable (3), and

- a release position (C) in which the pawl (25) allows of an upward movement of the coupling element (13) relative to the clamp portions (5, 7) in the event of the presence of the fall arrest device (1) on a cable (3), so that the fall arrest device can be disengaged from the cable.
A fall arrest device as claimed in claim 1, characterized in that the clamp portions (5, 7) run parallel to each other and the clamp surfaces (6, 8) are oblong and also run parallel to each other.
A fall arrest device as claimed in claim 1 or 2, characterized in that the hinge points (17, 19, 21, 23) of the clamp portions (5, 7) with one of the connecting arms (9, 11), seen in longitudinal direction of the cable (3) situated between the clamp portions during operation, are spaced apart from each other by a distance (20), where the lower one of the two hinge points (19, 23) is located between the two ends (9a, 9b, 11a, 11b) of the connecting arm (9, 11) and the first connecting arm end (9a, 11a) connected to the coupling element (13) is located on the same side of the cable (3) as this lower hinge point (19, 23), so that, in the event of a downward movement of the coupling element (13) relative to clamp portions (5, 7), the clamp surfaces (6, 8) are moved towards each other, and in the event of an upward movement of the coupling element (13) relative to clamp portions (5, 7), the clamp surfaces (6, 8) are moved away from each other.
A fall arrest device as claimed in claim 1, 2 or 3, characterized in that the fall arrest device comprises a spring (29) that pushes the pawl (25) to the clamp position (B).
A fall arrest device as claimed in claim 1, 2, 3 or 4, characterized in that the pawl (25) is provided with a pin (31) that can be moved in a curved groove (33) provided in the coupling element (13) when the pawl is rotated between the clamp position (B) and release position (C), and in that the coupling element comprises a blocking element (35) which, when the fall arrest device (1) is engaged with a cable (3) upside down, fits in the groove (33) under the influence of gravity and prevents the pin (31) from moving through the groove and thus blocks the pawl (25).