GB2514383A

GB2514383A - Safety release device for a sailing vessel harness

Info

Publication number: GB2514383A
Application number: GB1309222.6A
Authority: GB
Inventors: Benjamin Patrick Torrens; Nigel Victor Spurr
Original assignee: ARCHETYPE ENGINEERING SOLUTIONS Ltd
Current assignee: ARCHETYPE ENGINEERING SOLUTIONS Ltd
Priority date: 2013-05-22
Filing date: 2013-05-22
Publication date: 2014-11-26
Also published as: GB201309222D0

Abstract

A quick release coupling 1 for attaching a trapeze harness worn by a crew member to a vessel including a base plate with apertures or other features for attaching the coupling to the harness fabric structure, and a downward facing fork 2, attached rotatably 3 in one or more planes to the base plate. A shorter first leg of the fork forms a hook which is passed over and through a loop 6 tethered to the vessel. The longer second leg of the fork is trapped by a retention lever 4, which is held in position by a locking lever 5. The locking lever blocks 4 against rotation relative to the base plate and the first leg of the fork is maintained in a hooking position. In an emergency, releasing the locking lever and releasing the retention lever will free the second leg of the fork allowing it to rotate and allow the loop to slip free.

Description

Safety release device for a sailing vessel harness

Background

This invention relates to a device known as a trapeze harness. A trapeze harness is worn by a sailing vessel crew member and is selectively attached to a line generally running from a point on the vessels mast and allows the crew member to safely perform manoeuvres known as trapezing. When trapezing, the crew member is suspended outboard of the vessels hull, with hisTher feet resting on the edge of the hull and his/her weight is transferred from the trapeze harness to the line secured to the vessel's mast, thus providing a turning moment, counterbalancing the tuning moment generated by wind pressure on the vessel's sails. Similar devices are also used in other watersport activities such as sailboarding and ldtesurfing.

In the event of capsize, or other emergency incident, there is a risk that the crew member can become trapped by the connection between the trapeze harness and the line secured to the mast. Such entrapment has been known to result in injury and drowning. The resulting concern has resulted in the development of international standard No. ISO 10862:2009. for the performance of a releasable trapeze harness so that in the event of entrapment a crew member can readily release himself'herself from the vessel. The purpose of this invention is to provide a quick release trapeze harness that meets the requirements of the international standard, while being safe and secure in normal use.

Known solutions can require high force to operate, or be susceptible to inadvertent operation. This invention aims to solve these problems.

Statement of the invention

To achieve this, the invention proposes a quick release harness coupling comprising, a vertical base plate attached to the harness, a bracket attached to the base plate by a rivet and rotateable about the rivet, a pivot pin attached to the bracket parallel to the base plate, a fork with a stem rotationally suspended on to the pivot pin, a first fork leg used to hook downward over a loop tethered to a sailing vessel, a second fork leg substantially parallel to the first leg, a retention lever attached to the base plate by a rivet and rotateable about the rivet on an axis orthogonal to the base plate and being moveable by a user from a first position where the second leg of the fork is trapped in a slot in the retention lever to maintain the fork in a downward facing orientation, and an emergency release position where the second fork leg is freed from the retention lever so allowing the fork to tilt freely upward and sideways by a combination of rotation on the rivet and pivot pin respectively thereby allowing the first leg of the fork to disengage itself from the loop under the influence of a perpendicular or oblique tension load on the harness coupling.

In a preferred embodiment the retention lever is blocked in the normal-use fork rotation blocking position by a locking lever attached rotationally to the same pivot pin as the fork. The locking lever must be moved by the user to a non blocking position before the retention lever can be moved to a fork releasing position.

In the preferred embodiment the second leg of the fork is significantly longer than the first leg.

Advantages The two actions required for emergency re'ease of the couphng reduce the risk of inadvertent release of the coupling. A further advantage of the invention is the forces required to be applied during the release actions are relatively low, even when the harness coupling, loop and line are in tension. A further advantage of the invention is that it operates even if the crew member's body is turned obliquely to the direction of the tensioned line attached to the vessel.

Introduction to drawings

A description of the preferred embodiment follows with reference to the accompanying drawings.

Figure 1 shows an isometric view of the preferred embodiment with its parts in their normal non-emergency positions.

Figure 2 is an exploded isometric view of the preferred embodiment with its parts in their normal non emergency positions.

Figure 3 shows an isometric view with the locking lever moved to an unlocked position.

Figure 4 shows an isometric view with the retaining lever moved to its released position.

Figure 5 shows an isometric view with the fork rotated to one release position Figure 6a shows an isometric view with the fork rotated to a second release position.

Figure 6b shows an isometric view with the fork rotated to a third release position.

Figure 7a shows a front view of the coupling with its parts in their normal non-cmcrgcncy positions.

Figure 7b is a sectional view in direction AA of Figure 7a showing the forces acting on the legs of the fork.

Figure 8 is an isometric view showing more clearly the locking lever.

Figure 9 is an enlarged view of the top portion of fig 7b showing a locking detent for the locking lever.

Figure 1 shows the preferred embodiment of the device, principally comprising a baseplate (1), a fork (2), a pivot bracket (3), a retaining lever (4) and a locking lever (5). The ioop (6) attached to the sailing vessel (not shown) is inserted into the fork (6) between a first fork leg (11) and a second fork leg (12).

Figure 2 is an exploded view, showing the locking lever (5) and the fork (2) pivotally secured to bracket (3) about a common axis (19) using a pivot pin (7). The Bracket (3) is pivotally secured to the baseplate (1) around an axis (20) using a rivet (8). The retaining lever (4) is pivotally secured to the baseplate (1) about an axis (25) using a pivot rivet (6). In an alternative embodiment (not shown) the locking lever could be attached to the base plate by a separate bracket and rivet.

The base plate (1) has slots (9) provided through which pass webbing straps to secure the hook assembly to the fabric structure of the harness. Alternative constructions of the base plate may use holes, reinforced with eyelets, in place of the slots (9) for harness cords to pass through, or may include additional features or components to produce a "spreader bar" arrangement.

In thc normal, stablc condition as shown in figurc 1, forces applied to the base plate (1) in a direction away from the sailing vessel are transferred to the loop (6) via the pivot bracket (3) and retaining lever (4) to the fork (2). The stable nature of the hook is achieved due to engagement between the distal end (14) of the second fork leg (12), and a slot (13) formed in the retaining lever (4). This engagement blocks rotation of the bracket (3) about its pivot axis (20) and the fork about its pivot axis (19). To provide additional support to the retaining lever, a perpendicular flange (26) with an aperture (16) is formed out of the base plate (1). A box like portion (15) of the retaining lever (4) is engaged within the flange (26). This causes forces placed on the retaining lever (4) by the second fork leg (12) to pass directly to the baseplate (1), reducing stresses and dcflcctions in the retaining lever (4).

The risk of involuntaiy operation is reduced by the presence of the locking lever (5).

As best seen in Figures 2 & 8 a projection (18) on the locking lever (5) partially intrudes into a space (17) at the top of retaining lever (4) so preventing rotation of the retaining lever (4) about its axis (25).

Figure 9 illustrates an embodiment of a detent arrangement to retain the locking lever (5) in thc lockcd position. Thc fork (2) includes a protrusion (22) that intcrfcrcs with the rotational path about axis (19) of an elastic member (21) formed in locking lever (5). Anticlockwise rotation of the locking lever in figure 9 about axis (19) is resisted by the interference generated between the fork protrusion (22) and the elastic member (21), making it more difficult for the locking lever to be displaced from its locked position, whilst giving the user a "snap action" feel as it re-engages to the locked position. Under load, displacement of the retaining lever (4) in the direction of F2 could cause a small displacement of the locking lever. The retaining lever (4) includes a feature (23) which interferes with the locking lever elastic rnember (21), to increase the force required to move the locking lever (5) from its locked position. This feature further increases the security of the mechanism in usc.

Operation.

If the user desires to operate the fork release mechanism, the first operation, as shown in figure 3, is to displace the locking lever (5) from the locked position, sufficiently to remove the intrusion of the protrusion (18) of the locking lever (5) into the space (17) at the top of the retention lever (4). In this embodiment the displacement is away from the body of the user in the direction of arrow (10) in figure 3.

Displacement of the locking lever (5) will not cause the retaining lever (4) to disengage from the hook (2) as the forces placed on the retaining lever (4) by the fork (2) do not generate any turning moments about the displacement axis (25) of the retaining lever (4). The second action of the user is then to displace the retaining lever (4) in the direction of an arrow feature (29) formed in the retaining lever (4).

Anticlockwise rotation of the retaining lever (4) about its axis (25), as shown in figure 4, causes sufficient displacement of the slot (13) to disengage with distal end (14) of the second leg (12) of the fork (2). Once free of the retaining lever, the fork is able to rotate about its pivot axis (19) as shown in figures, and the bracket (20) is free to rotate about its pivot axis (20) as shown in figures 6a and 6b. Thus the fork (2) is able to align its open end with the direction of force from the loop, causing separation of the hook from the loop, and hence, release of the user from potential entrapment.

In order to ensure ease of use under highly loaded conditions, the design of the fork (2) is proportioned to minimise the forces placed on the retaining lever (4). Preferred geometry is shown in figures 7a and 7b, whereby the force Fl applied to the fork (2) by the loop (6) generates a turning moment about the fork axis (19). Minimising radius Ri and maximising radius R2 causes a significant reduction in F2 applied to the retaining lever (4) by second leg (12) of the fork (2). It is expected that the ratio of R2 to Ri is at least 2:1. In the preferred embodiment it is considerably higher. To facilitate greater convenience to the user, further reduction in operating forces are achieved by, with reference to figure 7, minimising the distance R3 from the retaining lever pocket (13) to the pivot axis (25), whilst maximising the distance R4 from the retaining lever pivot axis (25) to the arrow feature (29).