GB2089876A - Twistlock - Google Patents

Abstract

A twistlock includes a bolt 1 which in the released position is semi- retracted into body 30, that is with its underside flush with the top plate 31 of the body of the twistlock. The bolt 1 is slideably supported in body 30 which is mounted slightly below the level of the support faces between the vehicle and the freight container so that the container clears the retracted twistlock. A handle 5 is connected to cam means 4, 34, 35 which lifts the bolt 1 from its lowered to its raised position on rotation of the handle 5 about a horizontal axis and which is connected to the bolt 1 so that in the raised position of the bolt the handle 5 can rotate the bolt. Spring 2 urges the bolt downwardly to hold the container firmly and also causes cam lever 4 to engage stop 12, with the effect that the bolt must be lifted slightly so that lever 4 clears stop 12 before bolt can be released. <IMAGE>

Description

SPECIFICATION Twistlock The present invention relates to a locating and restraining device for a freight container demountable body of the twist-lock kind.

It is common practice to use twistlocks to secure demountable bodies on their chassis and these are normally of the non-retractable type, which entails lifting the body to such a height that it will clear the top of the twistlocks and then lowering it so that the twistlocks engage. The alternative is to provide a fully retractable twistlock.

We have now designed a semi-retractable twistlock in which the head of the twistlock can be lowered to a level where its underside is flush with the top of the body of the twistlock, so that the height of the body above its running position necessary to clear the twistlock is minimised.

Since the twistlock can be mounted slightly below the level of the support faces between the vehicle and body the difference as compared with a fully retractable twistlock is insignificant. The shape of the twistlock head also may in some cases help the alignment of the body.

It is also well known that twistlocks used for securing an demountable body are preferably spring loaded to avoid any free movement of the body in relation to the chassis. This entails some provision for vertical movement even with the non-retractable twistlock. Our new twistlock incorporates spring loading and provides a handle and lift bar to enable the heat to be raised against the pressure of the spring and then rotated to a locked position.

In one aspect the invention provides a locking and restraining device for a freight container or demountable vehicle body suitable for locking said container or demountable body to a transporter, comprising: a bolt having a head which is rotatable about a vertical axis between a locking position in which it traps beneath it an adjacent formation or formations constituting a socket and a release position in which the bolt is free to move downwardly to disengage the head from the socket; a body in which the bolt is slidably supported for movement between raised and lowered positions and for rotation about a vertical axis between locking and release positions; and a handle connected to cam means which lifts the bolt from its lowered to its raised position on rotation of the handle about a horizontal axis and which is connected to the bolt so that in the raised position of the bolt the handle can effect rotation of the bolt about a vertical axis between its locking and its release position.

In another aspect the invention provides a locating and restraining device for a freight container or demountable vehicle body suitable for locking said container or demountable body to a transporter, comprising a body and a bolt movable relatively to the body between a lowered position in which the underside of a fastening head included in the bolt is flush with the top of the body and a raised position in which the head in use would enter a socket in the container or demountable body and the bolt being rotatable in its raised position to a fastening position in which its head traps beneath it an adjacent formation or formations constituting a socket.

An embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is an end view of the twistlock with the working parts in the raised rotated hold-down position.

Figure 2 is a view of the twistlock of Figure 1 in vertical section on the line X-X with the working parts in their raised position when unlocked prior to rotation and with the lowered position of the head shown in chain dotted lines.

Figure 3 is a view of the twistlock in horizontal section on the line Y-Y and looking in the direction of the arrows; Figure 4 is a view on Z of the twistlock with the head in its rotated hold-down position; and Figures 5 and 6 are a side and fragmentary end view of a lift bar and handle which are incorporated into the twistlock.

In the drawings a twistlock body generally denoted by reference numeral 30 includes a top plate 31 and a bottom plate 32 formed with axially aligned through holes for supporting a shank 33 of a twistlock bolt assembly generally denoted by reference numeral 1 so that it may slide vertically in translation and rotate about its axis. A coil spring 2 is located between the underside of the top plate 31 and a washer 3 which is free to slide on the shank 33 of the bolt assembly. Beneath washer 3 a hole in the shank 33 accommodates a handle 5 which is assembled to a lift bar 4. The lift bar 4 has a first cam surface 34 which engages the bottom face of washer 3 and a second cam surface 35 which engages the top surface of the twistlock body bottom plate 32.

The sidewall of the twistlock body is formed with an inverted L-shaped slot in which the handle 5 is constrained, the slot having a horizontal limb at approximately mid height in the sidewall and a vertical limb depending from one end thereof.

The handle 5 is freely rotatable in the through hole in the shank 33 of the twistlock bolt, spring 2 lowers the bolt to the bottom of the travel where its head rests on the top face of top plate 31 as shown in Figure 2. Rotation of the handle 5 upwardly about a horizontal axis causes the lift bar 4 to bear on the plate 32 and thus pushes the bolt assembly upwards and forces washer 3 upwards against the pressure of the spring. The handle moves upwards in the vertical limb of the L-shaped slot and during this part of its travel the head of the bolt 1 is prevented from rotating about its vertical rotational axis.When the bolt has reached the top of its travel the handle 5 registers with the horizontal limb of the L-shaped slot 36 and the handle can then be rotated about a vertical axis to rotate the bolt through 90 from its release position to a locking position where its head traps beneath it a formation or formations 38 so as to clamp e.g. a container or demountable body in position. The arrangement shown is for a demountable body in which there are provided two parallel members 38 spaced so that the head of the bolt passes between them in one position but engages their upper surfaces after rotation through 900. There is clearance between the handle 5 and the slot 36 so that the bolt may travel downwards slightly from its fully raised position so that the load in the spring 2 is transmitted through shank 33 to the head of the bolt which is urged positively against the formations 38. A block 12 within the twistlock body forms a stop which prevents bolt rotation unless the hand 5 is rotated against the action of the spring 2 to bring the lift bar 4 clear of the block 12 at which point the head 1 has been lifted from engagement with the formations 38.

Claims (7)

1. A locating and restraining device for a freight container or demountable vehicle body suitable for locking said container or demountable body to a transporter, comprising: a bolt having a head which is rotatable about a vertical axis between a locking position in which it traps beneath it an adjacent formation or formations constituting a socket and a release position in which the bolt is free to move downwardly to disengage the head from the socket; a body in which the bolt is slidably supported for movement between raised and lowered positions and for rotation about a vertical axis between locking and release positions; and a handle connected to cam means which lifts the bolt from its lowered to its raised position on rotation of the handle about a horizontal axis and which is connected to the bolt so that in the raised position of the bolt the handle can effect rotation of the bolt about a vertical axis between its locking and its release position.

2. A device according to Claim 1 , wherein the handle is rigidly attached to a cam or lift bar acting between the base of the body and the base of the bolt via a lift handle.

3. A device according to Claim 1 or 2 wherein the handle is guided in an inverted L-shaped slot in the body, the vertical limb of the L defining the vertical travel of the bolt between raised and lowered positions and the horizontal limb of the slot defining rotational movement of the bolt between the locking and release positions.

4. A device according to Claim 3 wherein the handle can undergo limited vertical movement in the horizontal limb of the slot so that after the bolt has been moved to the locking position the head thereof is in spring-loaded contact with the socket formation or formations.

5. A device according to Claim 4, wherein the cam means engages under spring pressure a locking block within the body when the bolt is in the locking position to prevent reverse rotation of the bolt until the handle has been rotated about a horizontal axis to disengage the head from contact with the formation or formations constituting the socket.

6. A locating and restraining device for a freight container or demountable vehicle body suitable for locking said container or demountable body to a transporter, comprising a body and a bolt movable relatively to the body between a lowered position in which the underside of a fastening head included in the bolt is flush with the top of the body and a raised position in which the head in use would enter a socket in the container or demountable body and the bolt being rotatable in its raised position to a fastening position in which its head traps beneath it an adjacent formation or formations constituting the socket.

7. A locating and restraining device for a freight container substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.