GB2089874A - A locking bolt device - Google Patents

Abstract

A locking device for automatically locking together relatively movable parts has a bolt 6 carried by one part 3 and a co-operating eye member 7 carried by the other part 1 towards which the bolt is urged by a spring 8. Two abutment pins 6A, 6B are provided, the pin 6B acting when the members diverge to retain the bolt in a retracted position with a lateral projection 6C of the bolt overlying the pin 6A so that as the members move towards alignment, the bolt 6 is moved angularly until the projection 6C clears pin 6B, when the spring urges the bolt into its engaged position. The device is shown applied to a trailer, the parts 1 and 3 being relatively tiltable chassis portions. <IMAGE>

Description

SPECIFICATION A locking device This invention relates to a locking device for locking together a pair of relatively movable parts, and is primarily, but not exclusively, useful in locking together relatively tiltable chassis frame parts of a towable trailer.

In one form of trailer with which the locking device of the invention is particularly useful, a vehicle transporter ramp is carried on part of a trailer chassis which is tiltable relative to another chassis part which normally carries a towing hitch or similar arrangement for connection to a towing vehicle. The chassis parts are locked together during normal use, but can be released for relative tilting movement to permit loading and unloading of the trailer. In the event that the chassis parts are left unlocked or insecurely locked together, it is possible for the vehicle-carrying chassis part to tilt during use, with possible serious consequences to a carried vehicle, as well as to other vehicles on the road in the vicinity.

An object of the present invention is to provide an automatically operable locking device for locking together a pair of relatively movable parts, which device, when used in a vehicle transporter trailer having relatively tiltable chassis parts, automatically assumes a locked position when the chassis parts are brought into their normal positions for towing and thereby obviates the aforesaid probiem.

According to the present invention, a locking device for locking together a pair of relatively movable parts comprlses a bolt member carried by one of the parts and movable in its longitudinal direction into and out of locking engagement with an eye member carried by the other part, the bolt being spring-urged towards its position of locking engagement and angularly movable to enable it to be retained in a retracted position against the action of the spring by means of a lateral projection thereon engaging a first abutment surface carried by one of the parts, the bolt in said retracted position overlying a second abutment surface located further from the eye member than the first abutment surface, and the arrangement being such that, as relative movement of the movable parts occurs towards the position in which they are in parallel alignment, resulting relative movement of the abutment surfaces causes said second surface to pivot the lateral projection to a position in which it is raised clear of said first abutment surface, thereby enabling the spring to urge the bolt into engagement with the eye member to lock the members together.

In one convenient arrangement, the surfaces are formed on spigots upstanding respectively from the movable parts, the first surface being conveniently the circumferential surface of one spigot and the second surface being an end surface of the other spigot. The spigots are preferably mutually parallel and typically in the form of round pins.

The invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a diagrammatic representation of one form of a towing trailer embodying the locking device of the invention, and shown in one position of use; Figure 2 shows the trailer of Figure 1 in a different position of use; Figure 3 is an enlarged perspective view of part of the trailer of Figures 1 and 2, showing the locking device in more detail; Figure 4 is an enlarged side elevation of the forward end of the trailer of Figures 1 and 2, showing the locking device in the position which it assumes with the trailer in its Figure 1 position;; Figure 5 is a view similar to Figure 4 showing the locking device in an intermediate position of operation, and Figure 6 is a view similar to Figures 4 and 5 showing the locking device in its locked position.

Referring first to Figures 1 to 3, these show a towable vehicle transporter trailer in which the locking device of the invention is especially useful.

The trailer has a central longitudinal member or spine 1 pivotally connected to the trailer chassis at a location adjacent to the axle carrying a front pair of wheels 2. The spine 1 is provided, Tn conventional manner, with a standard coupling device (not shown) for hitching the trailer to a towing vehicle (not shown). The trailer also has a pair of outer longitudinal members 3 extendirg closely alongside the central spine 1, but ending short of the free end of the latter. The mernbers 3 carry spaced supports 4 and 5 for a locking bolt 6 which is movable into and out of locking engagement with an eye member 7 and cross brace 15, being urged into the locking position by a spring 8 surrounding the bolt and located between the support 4 and a transverse projection 6C of the bolt.The locking device also includes a pair of abutment pins, one 6A of which is rigidly mounted on the central spine 1, and the other 6B of which is slightly shorter than the pin 6A and is rigidly mounted on one of the members 3. The purpose of these abutment pins will be described in more detail hereinafter.

As can be seen from Figures 1 and 2, the members 3 may be tilted between a raised position (Figure 1) to enable a vehicle 9 to be loaded and unloaded and back to a horizontal position parallel with the spine 1 (Figure 2) for transportation purposes. The members 1 and 3 are locked together in the latter position by means of a security device consisting of a threaded bolt 10 pivotally connected at 11 to the spine 1 and being engageabie with a slotted plate 1 2 projecting forwardly of the members 3 and locked in position by means of a nut 13 rotatable by a handle 14.

With the security device in its operative position, as illustrated in Figures 2 and 6, the vehicle 9 may be transported in safety by towing the trailer behind the towing vehicle. However, in the event that the security device is not placed in its operative position, or is left insecure, it is possible for the members 3 to tilt to the Figure 1 position during towing, and this could have possibly disastrous consequences, the aforesaid locking device is provided to guard against such an eventuality by automatically assuming a locking position, in which is locks the members 1 and 3 together, whenever the members are moved into their aligned position (Figure 2) from a tilted position (Figure 1).

Figures 3 to 6 illustrate the locking device in various conditions of operation. Starting from the Figure 3 position in which the members 1 and 3 are locked in parallel alignment, it will be seen that the bolt 10 of the security device is engaged in the slotted plate 12 and locked in position by the nut 13. The bolt 6 of the locking device is also engaged with the eye 7 and cross brace 1 5. When it is desired to move the members 3 into the Figure 1 position, the nut 1 3 is slackened and the bolt 10 is pivoted out of the slotted plate 12.The bolt 6 is rotated in order to bring a transverse projection 6C thereof to a generally upright position in which it clears the pins 6A, 6B to enable the bolt 6 to be withdrawn from the cross brace 1 5 and eye 7, the bolt being retained initially in its withdrawn position, against the action of the spring 8, by rotating the withdrawn bolt to place the projection 6C behind the abutment 6A which, it will be seen from Figures 3 to 6, lies slightly rearwardly of the bolt B.As tilting of the members 3 is commenced, the bolt 6 and projection 6C are raised relative to the pin 6A and when the projection 6C reaches a position above the top of the pin 6A, it is urged forwardly by the spring 8 into abutment with the pin 6B, as illustrated in Figure 4.

As the members 3 are tilted back towards their position of alignment with the member 1 , the lateral projection 6C of the bolt 6, which now overlies the upper surface of the pin 6A, comes into abutment with that upper surface so that continued movement of the members 3 towards their position of alignment with the member 1 causes the projection 6C to be moved upwardly, by rotation of the bolt 6, until the projection 6C is raised above the pin 6B, at which time the spring 8 urges the bolt past the pins and into a position of abutment against the eye member 7.As the members 3 and 1 move finally into complete alignment, the bolt 6 comes correspondingly into alignment with the aperture of the eye member and is urged into its locking position through that aperture into the aperture in the cross brace 1 5. It will be appreciated that this locking action is brought about automatically by the members 3 and 1 assuming their aligned positions and without any intervention from an operative. The security bolt 10 may subsequently be engaged in the plate 12 and locked in the manner described above. However, in the event that the security bolt is not operated, or operated inadequately, the members 1 and 3 will remain securely locked together by automatic engagement of the bolt 6 with the eye member 7.

The locking device of the invention may be used in a variety of arrangements in which members are relatively moved between nonaligned and aligned positions. For example, the invention may be applicable to doors and gates in which automatic locking is required. It would also be possible to apply the device to members which perform relative parallel movement, rather than angular movement.

It will be understood that the various members of the locking device, such as the bolt, eye member and abutment may take any convenient form consistent with the performance of the function described herein.

Claims (7)

1. A locking device for locking together a pair of relatively movable parts comprising a bolt member carried by one of the parts and movable in its longitudinal direction into and out of locking engagement with an eye member carried by the other part, the bclt being spring-urged towards its position of locking engagement and angularly movable to enable it to be retained in a retracted position against the suction of the spring by means of a lateral projection thereon engaging a first abutment surface carried by one of the parts, the bolt in said retracted position overlying a second abutment surface located further from the eye member than the first abutment surface, and the arrangement being such that, as relative movement of the movable parts occurs towards the position in which they are in parallel alignment, resulting relative movement of the abutment surfaces causes said second surface to pivot the lateral projection to a position in which it is raised clear of said first abutment surface, thereby enabling the spring to urge the bolt into engagement with the eye member to lock the members together.

2. A locking device according to Claim 1 wherein the surfaces are on spigots upstanding respectivelyfrorn the movable parts.

3. A locking device according to Claim 2 wherein the first surface is the circumferential surface of one spigot and the second surface is an end surface of the other spigot.

4. A locking device according to Claim 2 or Claim 3 wherein the spigots are mutually parallel.

5. A locking device according to any one of Claims 2 to 4 wherein the spigots are round pins.

6. A locking device substantially as hereinbefore described with reference to the accompanying drawings.

7. A towable trailer having relatively tiltable chassis members and incorporating a locking device according to any of one Claims 1 to 6 arranged and operable automatically to lock together said chassis members when they are tilted from positions of mutual non-alignment to a mutually aligned position.