GB2233744A - Rope clutch - Google Patents

Abstract

A Rope Clutch is used for easily securing and releasing ropes, such as the sheets, which control the rig of a sailing vessel. Conventional clutches comprise relatively displaceable jaws with surfaces having serrations for the purpose of gripping the rope. These serrations lead to rapid rope wear. The present rope clutch provides at least one 13 of the jaws with a gripping surface provided by a nodular array, which may be of close packed hexagonal form. This significantly reduces rope wear without deterioration of the grip. <IMAGE>

Description

A ROPE CLUTCH The present invention relates to a rope clutch for selectively locking and releasing a rope passing through it. In the present specification "rope" should be interpreted broadly to refer to any elongate, flexible, rope-like member.

Rope clutches have applications in sailing vessels where they are used for the control of various elements of the rig, particularly the sheets (i.e., the ropes used to control the trim of the sails).

Known rope clutches such as those disclosed in European Patent Applications No's 0117466 and 0179302 comprise a frame with two jaws defining a rope passage. At least one of the jaws is swingably displaceable by the action of a manually operable lever mechanism to lock and release a rope in the passage between serrated gripping surfaces provided on the jaws. The serrated gripping surfaces have been found essential in order to provide sufficient grip. However, the action of the serrated gripping surfaces as they grip and release of the rope is such as to produce undesirable wear on the rope. This results in the need to frequently change expensive rope or risk the failure of the rope during use.

It is an object of the present invention to provide a rope clutch which alleviates the aforementioned disadvantage of the prior art.

According to the present invention there is provided a rope clutch comprising: a frame; first and second jaws provided in the frame each having a gripping surface and at least one of said gripping surfaces consisting of an array of nodular projections, the jaws being disposed in the frame so that the gripping surfaces are relatively opposed and define a passage for a rope extending through the rope clutch, at least one of the jaws being swingably mounted for relative displacement towards and away from the other jaw whereby the rope can be gripped and released by the gripping surfaces; and a lever mechanism manually operable to effect said displacement.

By having at least one of the gripping surfaces provided by an array of nodular projections it has been found that the rate of wear on the rope, caused by repeated locking and release of the rope clutch, is significantly reduce in comparison with conventional serrated gripping surfaces, while continuing to provide a satisfactory level of grip.

Preferably the nodules are disposed in a close packed hexagonal array which provides for maximum gripping effect. The nodular gripping surface may conveniently be formed by pressing from a suitable sheet material, such as stainless steel, and subsequently mounted in the frame.

In order to further enhance the performance of the nodular gripping surface may be concave instead of planar.

Normally in a rope clutch of the present type the swingable jaw or jaws will be configured and mounted so that when engaged with the rope; tension applied to the rope in one longitudinal direction will urge the jaws towards one another and, tension applied to the rope in the opposite direction will tend to part the jaws to allow for disengagement of the rope. In a preferred form of the rope clutch one jaw is fixed mounted and the other cam shaped.

In this form the gripping surface may advantageously be made concave to substantially complement the convex peripheral cam shape of the other gripping surface.

In an alternative form of the rope clutch one of the jaws is swingably mounted on a parallelogram mechanism. In this latter form of rope clutch the gripping surfaces may be planar.

One embodiment of a rope clutch constructed in accordance with the present invention will now be described, by way of examples only, with reference to the accompanying drawings; in which, Figure 1 is a sectional view of a rope clutch having a jaw with a nodular gripping surface, Figure 2 shows a plan view of the gripping surface provided by a jaw plate, Figure 3 is a sectional view through the line B-B of the jaw plate in figure 2, Figure 4 is a sectional view through the line C-C of the jaw plate in figure 2, Figure 5 is a sectional view of an alternative embodiment of a jaw plate.

With reference to figure 1 a rope clutch consists of a frame 1; first and second jaws 2 and 3 disposed opposite one another in the frame 1, to define a rope passage 4 (indicated by the dotted line) along which a rope passes through the clutch during use, the first jaw 2 is pivotally mounted for displacement towards and away from the second jaw 3 by the action of a lever mechanism 5.

In this embodiment the frame 1 consists of a moulded plastic housing having a base part 6, upstanding opposed side walls and opposed end walls 7. Apertures 8 are provided in each end wall 7, whereby the rope enters and leaves the rope clutch. Holes 9 are provided in the base part 6 for fastening the rope clutch to a support surface such as the superstructure of a yacht.

The first jaw 2 has a cam shaped profile 10 and is mounted on a pivot pin 11 to rotate about an axis extending perpendicular with respect to, and extending between the side walls. The surface defining the cam profile 10 is formed with serrations extending parallel to the axis of the pivot pin 11 in order to provide a first rope gripping surface.

The second jaw 3 is formed from an inwardly projecting part 12 of the base 6 and a jaw plate 13 which is fastened to the inner surface of the projecting part to provide a second gripping surface.

The jaw plate 13 is shown in more detail in figures 2 to 3, and consists of a steel plate 14 which is formed in a press to conform to the shape of the projecting part 12 upon which it is mounted. During the process of formation an array of nodular projections 15 is formed into the jaw plate 13 so that when the jaw plate 13 is mounted on the projecting part 12 the array of nodular projections provides the second gripping surface. The nodular projections 15 in the present embodiment are disposed in a close packed hexagonal array and the portion of the jaw plate 13 on which the array is formed is planar.

The lever mechanism 5 consists of a manually operable lever 16, mounted to rotate around a pivot pin 17.

The action of rotating the lever 16 actuates a linkage assembly 18, whereby the first jaw 2 is caused to rotate about the pin 11 to displace the first gripping surface away from the second gripping surface to allow the rope to run through the passage in the direction of arrow A.

Because of the cam shaped profile of the jaw 2 the first gripping surface, will be displaced towards or away from the second gripping surface, according to the direction of rotation and hence engage and lock a rope extending through the passage 4.

In use the rope clutch is arranged so that the tension is normally applied to the rope in the direction of the arrow A, in consequence the first jaw 2 tends to rotate into engagement with the rope to grip the rope.

In an alternative embodiment of the invention, as shown in figure 5, the jaw plate 13 is formed so that the gripping surface is concave and substantially complementary in profile to the profile of the first jaw 2.

In a still further embodiment of the invention (not shown) the gripping surface may be concave in section to complement the curved surface of the rope.

It should be realised that alternative methods of constructing the gripping surface/jaw plate are contemplated. These include moulding the nodular gripping surface from plastics or other suitable material or securing nodular elements, such as ball bearings, into a surface. Moulding the nodular gripping surface allows for the possibility of forming the surface as an integral part of the frame of the rope clutch.

Claims (8)

1. A rope clutch comprising: a frame; first and second jaws mounted in the frame and each having a gripping surface, at least one of said gripping surfaces consisting of an array of nodular projections, the jaws being mounted in the frame so that the gripping surfaces are relatively opposed and define a passage for a rope extending through the rope clutch, at least one of the jaws being swingably mounted for displacement towards and away from the other jaw, whereby a rope in the passage can be gripped and released by the gripping surfaces, and a lever mechanism manually operable to effect said displacement.

2. A rope clutch according to claim l wherein the nodules of the nodular gripping surface are arranged in an hexagonal array.

3. A rope clutch according to claim 1 or claim 2 wherein the nodular gripping surface is formed by pressing a sheet of material.

4. A rope clutch according to claim 3 wherein the material in stainless steel.

5. A rope clutch according to claim 1 or claim 2 wherein the nodular gripping surface is formed by moulding a plastics material.

6. A rope clutch according to any one of the preceding claims wherein one of the gripping surfaces has a convex profile and the other has a substantially complementary concave profile.

7. A rope clutch according to any one of the preceding claims wherein at least one of the gripping surfaces has a concave section to accommodate the rope.

8. A rope clutch as herein described with reference to the accompanying drawings.