Fall arrest device with blocking catch

Technical Field of the Invention

The invention relates to a follower fall arrest device used with a fixed safety rope, and comprising a body equipped with a restraint system arranged to occupy either an active locking position in case of a fall or an inactive unlocking position enabling user progression along the rope in the direction of ascent, or in the opposite direction at a controlled descent, said retainer comprising:<ul><li>an articulated support arm about a first axis of the body,</li><li>a cylindrical wheel shaped locking wheel freely rotatable mounted on a second shaft integral with the support arm,</li><li>and a centrifugal clutch arranged between a drive member of the roller and the support arm so as to occupy a disengaged position or an engaged position.</li></ul>

PRIOR ART

During normal use of climb or descent, fall arrest devices follow the progression of the person along the rope without causing blockage. The person is free to move without any manual intervention of unblocking the fall arrest system. Lev blocking occurs only in case of fall.

The known fall arrest devices restraint system generally comprises a pivoting lever having at one end a fastening ring for connection to a harness, and at the opposite end a rope locking cam. Such an arrangement behaves as a cleat, which may prevent the blockage if the user were to grab the lever in case of fall.

WO 00/24471 relates to a bi-directional locking device for a fall arrest device comprising a locking member equipped with two cams controlled independently by a common locking member in response to an abrupt change in weight. Blocking each of the cams depends on the inclination of the cord relative to the apparatus chassis.

Document US 4923037 discloses a fall arrest device having a restraint system consisting of an articulated support arm, which is equipped with a spur gear mounted for free rotation, and a mechanical coupling arranged centrifugal ratchet. The periphery of the wheel has a series of teeth forming a pinion causes rotation of the wheel by effect of friction with the cable. To insert the vertical lifeline in the fall arrest system, it is necessary to use an articulated U comière, and rotate outwards, which complicates operations. The use of springs in the form of pins does not allow to control accurately the coupling locking threshold.

The invention

The object of the invention to provide a fall arrest device for a fixed rope, allowing for precise locking threshold depending on the speed or acceleration of the locking wheel.

The fall arrest device according to the invention is characterized in that the centrifugal coupling means comprises at least one flyweight movable along a ramp of the drive member against a compression spring, and an interface bond engaged inside a cylindrical rim of the support arm to transmit the elastic force of the spring to the flyweight.

During normal use of up or down, the clutch is in the disengaged position and the fall arrest device follows the progression of the person along the rope without any manual unlocking action of the restraint system. If dropped, the blockage occurs automatically in a prédéterminné threshold. In this case, the coupling is in the engaged position resulting in a pressure of the roller against the rope.

According to a preferred embodiment, the flyweight is cylindrical in shape and cooperates in the engaged position with the cylindrical rim of the support arm. The peripheral surface of the flyweight and of the ramp of the drive member is advantageously striated, so as to form a rack.

Preferably, the centrifugal clutch comprises two flyweights and two compression springs arranged symmetrically with respect to the second axis of the roller.

BRIEF DESCRIPTION OF DRAWINGS

Other advantages and features will become more clearly apparent from the following description of one embodiment of the invention given by way of non-limiting example and represented in the accompanying drawings in which:<ul><li>Figure 1 is a perspective view of the fall arrest device according to the invention, which is installed on a lifeline after setting up a carabiner clip;</li><li>2 shows an exploded perspective view of the fall protection apparatus of Figure 1, after removal from the rope;</li><li>Figure 3 is an exploded perspective view of the retainer of the device fall;</li><li>Figure 4 is a locking wheel sectional view with the centrifugal coupling weights in the disengaged position; </li><li>Figures 5 and 6 are sectional views along the lines LL and GG of Figure 4;</li><li>Figure 7 is an identical view to Figure 4 in the engaged position of the coupling for the lock in case of fall.</li></ul>

Description of a preferred embodiment

Figures 1 to 7, a fall arrest device 10 is used for the security of a person moving along a rope 12 fixed insurance. A hook 14 is hooked to the fall arrest device 10 so as to be connected to the harness, either directly or via a lanyard to absorption. During normal use of the rise or fall, the fall arrest device 10 follows the progression of the person along the rope 12 without causing locking. The person is then free to move without any manual unlocking action of the fall arrest device 10.

The fall arrest device 10 is composed of a rigid body 16, and a movable retainer 18 cooperates with the rope 12 to occupy either an active locking position in case of a fall or an inactive unlocking position in the direction of the rise, or in the opposite direction at a controlled descent. The body 16 preferably made of metal, comprises a straight chute 20 U-shaped for the passage of the rope 12, and a bracket 22 for mounting a first axis 24 extending transversely to the direction of the channel 20 . the upper chute portion 20 is pierced by two holes 23 to allow the passage of the carabiner 14.

The retainer 18 comprises a support arm 26 articulated on the first spindle 24, and a roller hold 28 in the form of free rotation wheel mounted on a second shaft 30 integral with the support arm 26. The roller peripheral surface blocker 28 is cylindrical, and is provided with a plurality of studs 32 each having a predetermined inclination relative to the radial direction passing through the axis 30. a torsion spring 31 is threaded onto the first shaft 24, and biases the support arm 26 direction of the channel 20.

The locking wheel 28 has a drive member 33 internally, coaxially traversed by a bush 36 of tubular housing 30 of the second fixed axis. Inside the hold roller 28 is in addition a centrifugal clutch 38 formed by a pair of cylindrical weights 40 arranged between opposed ramps 42 of the drive member 33 and a circular flange 44 of the support arm 26.

A pair of compression springs 46 urges the centrifugal clutch 38 to the disengaged position so as to provide a radial clearance between the flyweights 40 and the cylindrical flange 44 of the drive member 33 of the arm 26 (Figure 4). A link interface 45 is engaged inside the rim 44, and transmits the expansion forces of the springs 40 to the weights 40. The presence of the connecting interface 45 and compression springs 46 precisely defines the threshold clutch of the centrifugal clutch 38 according to the speed or acceleration of the drive member 33 of the rotary wheel 28.

If user falls, the abrupt rotation in the direction of the arrow F1 of the drive member 33 of the locking wheel 28 about the second axis 30 causes movement of the flyweights 40 by centrifugal effect towards the engaged position ( Figure 7). The weights 40 are subjected to a centrifugal force which is greater and in the opposite direction to the restoring force of the springs 46. This movement along the ramps 42 causes compression of the springs 46 and creates a wedging effect of the flyweights 40 against the flange 44. the roller 28 is thus fixed to the arm support 26, so as to provide a cleat which is pivotable about the first axis 24, and to block the fall by blocking the rope 12.

The weights of the peripheral surface 40 and ramps 42 of the drive member 33 is preferably serrated, to form a rack facilitating engagement and disengagement of the centrifugal clutch 38. The compression springs 46 have stiffness uniforms of controlling the coupling threshold.