GB2158140A

GB2158140A - Releasable two-part fastener

Info

Publication number: GB2158140A
Application number: GB08411217A
Authority: GB
Inventors: Peter Thomas Mence Nott
Original assignee: PERKSON FORGINGS Ltd
Current assignee: PERKSON FORGINGS Ltd
Priority date: 1984-05-02
Filing date: 1984-05-02
Publication date: 1985-11-06
Also published as: GB8411217D0

Abstract

The fastener comprises a keeper (10) and a hook element (11) having handle (16). In the closed condition, a bar (14) of the keeper is nipped between the hook element (11) and a seat (27) on a carrier (12) for the hook element. The catch has an over-centre action due to the action of a spring 26. <IMAGE>

Description

SPECIFICATION Releasable two-part fastener This invention relates to a releasable two-part fastener comprising a keeper, a catch for releasably engaging the keeper, a carrier for the catch and a handle to which a user can apply a force to move the catch relative to the carrier and the keeper. A fastener of the kind described is used to restrain movement of two members from a predetermined relative position. The keeper is fixed with respect to one of the members and the carrier is fixed with respect to the other member. The catch and the handle are both mounted on the carrier for movement relative thereto to enable the catch to be engaged with and released from the keeper. The carrier also may engage the keeper when the members are in said predetermined position.A fastener of the kind described is commonly used for releasably securing a door in a closed position relative to a door frame.

According to a first aspect of the present invention, a fastener of the kind described is so arranged that movement of the catch relative to the keeper and the carrier in a manner to release the fastener but without movement of the carrier relative to the keeper causes the catch to engage the keeper under a pressure which increases and then decreases as the catch moves to a position in which the fastener is released.

In the preferred arrangement, the catch includes a contact surface for engaging the keeper and the carrier has a control surface or control surfaces which engage the catch in a manner to permit swinging of the contact surface relative to the carrier but to restrain all other movement of the catch relative to the carrier.

According to a second aspect of the invention, there is provided a fastener of the kind described wherein the catch swings relative to the carrier into and out of engagement with the keeper in such a manner that a point on the surface of the catch which engages the keeper moves relative to the carrier in a plane and wherein, during movement of said point in said plane, a point on the handle moves in a plane which is parallel to the plane in which said point on the catch moves.

According to a third aspect of the invention, there is provided a fastener of the kind described wherein the catch is trapped between control surfaces on the carrier and said control surfaces limit movement of the catch relative to the carrier without reliance on a pivot pin.

The or each control surface may be a part of a surface of revolution about a pivot axis defined by the carrier.

In the preferred structure, the carrier has at least two control surfaces which are concentric and mutually opposed to define between them an arcuate gap and the catch has an arcuate limb which slides in the gap.

A line which is normal to the contact surface of the catch at a position where the surface is engaged by the keeper, in the closed condition of the fastener, is preferably so inclined to a line joining that position with the pivot axis that application to the fastener of a force tending to move the carrier from the keeper in the direction of opening movement urges the catch towards the closed position.

According to a further aspect of the invention, the handle of a fastener of the kind described is an integral part of the catch. By describing the handle as an integral part of the catch, we mean that the catch, including the handle, is formed of a single piece of material or alternatively, the handle and a further part of the catch are formed separately and are rigidly secured together so that the handle necessarily participates in movement of the catch.

An example of a fastener embodying each aspect of the invention will now be described, with reference to the accompanying drawings, wherein: Figure 1 shows a front elevation of the fastener in a closed condition; Figure 2 shows a cross-section on the line ll-ll of Fig. 1; and Figure 3 is a fragmentary view similar to Fig. 2 but illustrating the parts in a released condition of the fastener.

The fastener illustrated in the drawings comprises a keeper 10, a catch 11 and a carrier 1 2 on which the catch is mounted for limited movement relative to the carrier. In use, the keeper and the carrier would be mounted on relatively movable members. Typically, the keeper would be mounted on a frame and the carrier would be mounted on an associated closure member in a position such that, when the closure member is closed to the frame, the carrier engages the keeper, as shown in Fig. 3.

The keeper 10 comprises a body 1 3 for engaging the door frame or other member on which the keeper is to be mounted and a bar 14, opposite end portions of which are rigidly connected with the body 1 3. An intermediate portion of the bar 14 is spaced away from the body to provide a clearance for access by the catch 11 and carrier 1 2. The bar 14 is rectilinear and, where the handle is required to swing horizontally, the axis of the bar 1 4 would be vertical. The body 1 3 would be secured to the frame by screws, bolts, rivets or other fasteners.

The catch 11 is of generally elongated shape and comprises three limbs, namely a first limb 1 5 for engagement with the bar 14 and which defines one end portion of the catch, a second limb 1 6 which constitutes a handle of the catch and defines a second end portion of the catch and a third, intermediate limb 1 7 for co-operation with the carrier 12.

The limbs 15, 1 6 and 1 7 are integral one with the other. These limbs may be formed of a single piece of material. However, as shown in the drawings, the catch is preferably formed of two components which are initially separate one from the other and are rigidly secured together, for example by riveting or welding. The first of these components includes the limb 1 5 and the second of these components includes the limbs 1 6 and 1 7.

All parts of the catch, including the handle, participate in movement of the catch relative to the carrier 1 2.

In the example illustrated, the third limb 1 7 of the catch includes two separate but substantially identical parts 17a, 1 7b which cooperate with the carrier and which are spaced apart in a direction transverse to the length of the catch. The part 1 7a lies adjacent to an upper edge of the catch and the part 1 7b lies adjacent to a lower edge of the catch, when the fastener is oriented as shown in the drawings. Each of the parts 1 7a and 1 7b is partcylindrical and these parts have a common axis of curvature which is a pivot axis 18 of the fastener.

The carrier 1 2 would be mounted on a door or other member by means of screws, bolts, rivets or other fasteners. The carrier has control surfaces 20 and 21 which are surfaces of revolution about the axis 1 8 and are spaced apart radially of that axis by an arcuate gap 1 9. The part 1 7a of the third limb of the catch is received in this gap with sufficient clearance to permit sliding of the limb between the surfaces 20 and 21 around the pivot axis. The carrier has further control surfaces arranged in a corresponding manner to receive between them the part 1 7b of the third limb of the catch.

The carrier 1 2 is formed in two parts 22 and 23 respectively. The control surface 20 is provided on the carrier part 22 and the control surface 21 is provided on the carrier part 23. During assembly of the catch with the carrier, the part 1 7a of the third limb of the catch is seated on the control surface 20 prior to assembly of the carrier parts with one another. The carrier part 23 is then applied and rigidly secured to the carrier part 22, thereby trapping the catch 11 and rendering the catch captive in the carrier.It will be noted that travel of the third limb of the catch along the gap 1 9 is limited, at one extremity by engagement of the first limb 1 5 of the catch with a rear wall 24 of the carrier part 22 and, at the other extremity when the carrier is remote from the keeper 10, by engagement of the first limb 1 5 of the catch with the carrier part 23. Thus, the third limb of the catch cannot be withdrawn completely from the gap 1 9. The carrier parts 22 and 23 may be releasably or permanently secured together, as required. If they are releasably secured together, then the catch can readily be replaced by a new one by reversing and then repeating the assembly procedure hereinbefore described.

There is in the rear wall 24 an opening 25 through which the first limb 1 5 of the catch can move. It will be noted that the dimension of the limb 1 5 which extends in a direction parallel to the pivot axis 18 and the corresponding dimension of the opening 25 are both considerably smaller than the corresponding dimensions of the carrier part 22 and of the third limb 1 7 of the catch. Parts of the rear wall 24 above and below the opening 25 present seating surfaces 27 for receiving the bar 14.

When the fastener is in an open condition, both the catch 11 and the carrier 12 are spaced from the keeper 10. This corresponds to the open position of a door to which the fastener is fitted. A spring 26 (shown only in Fig. 3) acts between the carrier and the catch, with which it is connected at respective positions remote from the pivot axis 18, to urge the catch to a closed position relative to the carrier, which position is illustrated in Fig. 2.

When the catch is in the closed position, the handle 1 6 is disposed entirely or is almost disposed with a recess defined by the carrier part 22.

Prior to closing the fastener, it is necessary for a user to swing the catch 11 to the position illustrated in Fig. 3, in which the handle 1 6 is disposed entirely outside the carrier 1 2 and in which the first limb 1 5 of the catch is spaced from the seating surfaces 27 of the carrier in a direction along the carrier so that the limb 1 5 can move past the bar 14 without contacting that bar when the carrier is moved relative to the keeper into the closed position illustrated in Fig. 3, in which the seating surfaces 27 engage the bar 14.

The condition of the fastener illustrated in Fig. 3, with the catch 11 clear of the bar 14, is called herein the released condition. Once the carrier 1 2 has been moved into or almost into its closed position, swinging of the catch 11 relative to the carrier 12 in a direction to move the handle 16 into the recess defined by the carrier part 22 will move a contact surface 28 of the limb 1 5 of the catch into engagement with the bar 14 at a side thereof generally opposite to the side at which the seating surfaces 27 engage the bar. Thus, the bar is trapped between the contact surface 28 of the catch and the seating surfaces 27 of the carrier.

The contact surface 28 includes a flat part 29, a concave part 30 and a convex part 31 lying between the flat part and the concave part. The curved parts of the contact surface 28 lie between the flat part 29 and the handle 1 6. During closing of the fastener, contact between the bar 14 and the contact surface 28 is initially established at the flat part 29. Continued swinging of the catch relative to the carrier drives the contact surface over the bar 14 so that contact with the bar is established successively at the convex part 31 and then the concave part 30 of the surface. Such movement is accompanied by a change in the pressure under which the contact surface 28 engages the bar 14. The pressure increases to a maximum value and then decreases when the concave part 30 of the contact surface moves into contact with the bar 14.This pressure is generally sufficient to eliminate any clearance between the bar 14 and the seating surfaces 27 and is also sufficient to stress parts of the fastener within their respective elastic limits. This stress is at least partly relieved when the closed condition of the fastener illustrated in Fig. 2 is established.

It will be appreciated that releasing of the fastener requires the application of a substantial force to the handle 1 6 in a direction to urge that handle away from the recess defined by the carrier part 22. During swinging of the catch from the position illustrated in Fig. 2, the pressure under which the contact surface 28 engages the bar 14 of the keeper initiaily increases and subsequently decreases as the catch is moved out of contact with the bar.

The fastener is then in the released condition shown in Fig. 3 and can be moved to the open conditon by moving the carrier 1 2 away from the keeper. Usually, such movement will occur before swinging of the catch 11 to the position illustrated in Fig. 3 is completed, so that contact will be maintained between the flat part 29 of the contact surface and the bar 14 until the free end of the limb 1 5 of the catch moves past the bar. However, until the pressure under which the contact surface 28 engages the bar 14 decreases from its maximum value, the seating surfaces 27 will be held in contact with the bar 14.

It will be appreciated that, whilst a contact surface 28 having a flat part 29 is preferred, the contact surface may alternatively be curved throughout its length, the radius of curvature varying in a direction along the catch 11.

Whilst the fastener is in the closed condition, a force tending to separate the carrier 1 2 from the keeper 10, for example a force tending to open a door which is held closed by the fastener, will be exerted by the bar 14 on the catch 11 at the concave part 30 of the contact surface. When the fastener is viewed as shown in Fig. 2, the centre of curvature 33 of the part 30 of the contact surface lies to the left of the pivot axis 1 8. The force exerted by the keeper on the catch acts substantially along a line joining the position of contact with the centre of curvature 33 and produces a turning moment about the pivot axis 1 8 which urge the catch 11 towards its closed position.An increase in the force tending to separate the carrier 1 2 from the keeper 10 (unless the force is sufficiently large to deform the fastener significantly) increases the moment urging the catch towards its closed position.

The seating surface 27 of the carrier 1 2 is so formed as to so control the relative positions of the carrier and keeper that the position at which the keeper contacts the catch 11 is such as to ensure that application to the fastener of a force tending to separate the carrier from the keeper will urge the catch 11 into its closed position. In the example illustrated, a line joining the centre of the bar 1 4 with the pivot axis 1 8 is inclined at 45 to the direction of opening movement of the carrier 1 2 relative to the keeper. A line joining the centre -of the bar 14 with the centre of curvature 33 of the contact surface part 30 is inclined at an angle of 60 to the direction of opening movement of the carrier.When the fastener is viewed as shown in Fig. 2, the position at which the bar 14 contacts the catch 11 lies below and to the right of the pivot axis 1 8. Each of the seating surfaces 27 of the carrier includes a concave part lying between flat parts. Of these flat parts, that which is shown on the left in Figs. 2 and 3 is inclined at an angle of 15' to the direction of opening movement of the carrier 1 2 relative to the keeper 10 and the flat part which is shown on the right in Figs. 2 and 3 is inclined at 45 to the direction of opening movement.

As shown in Fig. 2, a leaf spring 32 (omitted from Fig. 3) may be provided in the carrier 1 2 to bear against the bar 14 in the closed condition of the fastener to take up any clearance which may exist in the closed condition and which may permit rattling. Such a spring is useful in a case where the pressure between the contact surface 28 of the catch 11 and the bar 14 of the keeper is reduced to zero when the part of the contact surface to which the bar 14 is closest is the concave part 30.

The fastener illustrated in the accompanying drawings may be modified to restrict the range of angular movement of the handle 1 6 relative to the carrier 12, for example to a range of 60' or a somewhat smaller angle.

Means may be provided for retaining the handle 1 6 in the position shown in Fig. 2 and thus to maintain the fastener in the closed condition. One example of such retaining means which may be provided comprises a pin disposed in the recess defined by the carrier 1 2 and fixed with respect thereto and a leaf spring 35 rigidly connected adjacent to one of its ends to the handle 1 6 of the catch, the leaf spring having a concave surface which can snap over the pin 34 when the catch is moved to its closed position.

The parts 22 and 23 of the carrier may be formed by die-casting but, in the example illustrated, these parts are pressings.

The fastener is useful on vehicles, for example to secure in a closed position a tailgate or drop sides of a vehicle body.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, may, separately or any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A releasable two-part fastener comprising a keeper, a catch for releasably engaging the keeper, a carrier for the catch and a handle to which a user can apply a force to move the catch relative to the carrier and to the keeper, so arranged that the resistance to movement of the catch relative to the keeper and to the carrier in a manner to release the fastener but without movement of the carrier relative to the keeper increases and then decreases as the catch moves to a position in which the fastener is released and wherein the handle is integral with the catch.

2. A releasable two-part fastener comprising a keeper, a catch for releasably engaging the keeper, a carrier for the catch and a handle to which a user can apply a force to move the catch relative to the carrier and to the keeper, so arranged that movement of the catch relative to the keeper and to the carrier in a manner to release the fastener but without movement of the carrier relative to the keeper causes the catch to engage the keeper under a pressure which increases and then decreases as the catch moves to a position in which the fastener is released.

3. A releasable two-part fastener comprising a keeper, a catch for releasably engaging the keeper, a carrier for the catch and a handle to which a user can apply a force to move the catch relative to the carrier and to the keeper wherein the catch is trapped between control surfaces on the carrier, said control surfaces limiting movement of the catch relative to the carrier without reliance on a pivot pin.

4. A releasable two-part fastener comprising a keeper, a catch for releasably engaging the keeper, a carrier for the catch and a handle to which a user can apply a force to move the catch relative to the carrier and to the keeper wherein the handle is an integral part of the catch.

5. A releasable two-part fastener comprising a keeper, a catch for releasably engaging the keeper, a carrier for the catch and a handle to which a user can apply a force to move the catch relative to the carrier and to the keeper, wherein the catch swings relative to the carrier into and out of engagement with the keeper so that a point on the surface of the catch which engages the keeper, moves in a plane and wherein, during swinging of the catch relative to the carrier, a point on the handle moves in plane which is parallel to the plane in which said point on the catch moves.

6. A fastener according to any one of Claim 1, 2, 4 and 5 wherein the catch includes a contact surface for engaging the keeper and the carrier has a control surface or control surfaces which engages or engage the catch in a manner to permit swinging of the contact surface relative to the carrier but to restrain all other movement of the catch relative to the carrier.

7. A fastener according to Claim 6 wherein the contact surface includes a first part which is curved and wherein the curvature of said first part varies along the contact surface.

8. A fastener according to Claim 3 wherein the catch includes a contact surface for engaging the keeper and which surface includes a first part which is curved, and wherein the curvature of said first part varies along the contact surface.

9. A fastener according to Claim 7 or Claim 8 wherein said contact surface further includes a second part which is flat or which is less curved than is the first part.

10. A fastener according to Claim 9 wherein the first part of said contact surface is disposed between the second part of the contact surface and the handle.

11. A fastener according to any one of Claims 3 and 6 to 10 wherein the or each contact surface is a part of a surface of revolution about a pivot axis defined by the carrier.

1 2. A fastener according to Claim 11 wherein the carrier has at least two contact surfaces which are concentric and mutually opposed to define between them an arcuate gap and wherein the catch has an arcuate limb which slides in the gap.

1 3. A fastener substantially as herein described with reference to and as shown in the accompanying drawings.

14. Any novel feature or novel combination of features disclosed herein and/or shown in the accompanying drawings.