GB1574708A - Locating and locking devices - Google Patents

Description

(54) IMPROVEMENTS IN LOCATING AND LOCKING DEVICES (71) We, Multi-Stroke Handbrake Controls Limited, a British Company, of Green Lane, Tewkesbury, Gloucestershire, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following state ment:- This invention relates to devices for use to locate and lock transport containers in position on road vehicle trailers, railway vehicles and the like. It relates particularly to devices of the type commonly referred to as "twistlocks" (which term is used hereafter) and which employ a rotary locking bolt which can be raised and turned to lock a container in position and which is retractable when not in use, the bolt being associated with a locating member against which the container locates.

It is an object of the invention to provide a twistlock which includes means enabling the rotary locking bolt to be screwed down thereby permitting a clamping action to be obtained.

According to the invention a twistlock comprises a stud for locating and fastening a superposed structure such as a freight container, wherein the stud is slidable from a retracted position within a mounting and can then be turned to seat upon the mounting, the stud having a through bolt with a head which caps the stud, which bolt can be raised and turned to orient the head for locking, characterised by a manually operable nut or collar screwing on the lower end of the bolt stem and rotatable to abut the stud and also, in the raised position of the stud, to abut the mounting, thereby serving as a manipulative element for retracting, raising and turning the stud and bolt as a unit with the nut or collar screwed against the stud, for raising and turning the bolt with respect to the stud with the nut or collar unscrewed from the stud and for tightening the fastening by rotation of the nut or collar against the mounting.

The locking bolt is preferably arranged so that, when the complete assembly is in the raised operative position, the bolt can be raised into a position-in which it is no longer held against rotation relative to the locating member, the locking bolt then being turned by means of the handle into its locking position in which, upon rotation of the handle relative to the locking bolt, the locking bolt is moved axially relative to the locating member whereby the corner of a container with which the twistlock is engaged can be clamped in position The mounting body may comprise a backplate, an apertured top plate and two side guide plates between which the assembly is slidable, the locating member comprising a lower cylindrical stem portion, which is a free sliding fit between the guide plates, and an enlarged upper end portion which is effective for container location and is also freely slidable between the guide plates when within the mounting body.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings, the embodimen being in the form of a twistlock based on that described and claimed in Patent Specification No. 1,419,943 to which reference should be made.

In the drawings: Figure 1 is a front view of the twistlock embodying the present invention, Figure 2 is a corresponding side view but with a locking bolt in operative position, Figure 3 is á plan view corresponding to Figure l,and Figure 4 is a sectional view of the twistlock in a retracted state.

In the following description and appended claims the terms "upper" "upwardly'; "top", "lower" dnd "beneath" are to be applied when the twistlock is in the general attitude illustrated in Figures 1,2 and 4.

The twistlock includes a fabricated steel mounting body 10 as described in Specification No. 1,419,943, the body having a flat steel backplate 11, allowing flush fitting at the rear, a slightly wider and flat top plate 12 which has a circular through aperture 12a and projects a short distance at the rear of the backplate 11, and two flat side guide plates 13 which project forwardly from the backplate 11 and are inset with respect to the side edges threeof. The mounting body 10, formed by welding the plates 11, 12 and 13 together, can be welded around its complete periphery to a vehicle to provide firm fixing.

The mounting body carries a central assembly 14 which differs from that described in the aforesaid specification in having a locking bolt which can be screwed down for clamping and which can also be engaged with the locating member to rotate therewith. As shown in the drawings, the assembly 14 consists of a container-locating member 15 slidable between the guide plates 13, and a twistlock bolt 16 with a domed and ridged head 16a, which rests on the top of the locating member 15, and a stem 16b which passes centrally through the member 15 and has a screw-threaded lower end portion 16c. The latter passes through and engages an internally threaded collar 17 forming part of a handle 18 having a hand-grip portion 19. A retaining pin 20 passes diametrally through the threaded portion 1 6c of the stem 16 to limit the travel of the stem through the collar.

The container-locating member 15 has a lower cylindrical stem portion 15a and an enlarged upper portion 15b which has parallel side flats 15c, providing a width equal to the diameter of the lower portion 15a, and arcuate ends centred on the bolt axis to provide a free sliding and rotational fit in the circular aperture 12a of the top plate 12 of the mounting body 10.

The top end of the upper portion 15b is formed as an upwardly directed tapered but flattened nose with inclined flats or bevels 15d and end surfaces in a radial plane.

The domed and ridged head 16a of the bolt is of generally known form and is shaped exactly to overlie and cap the flattened nose, that is to have the eight-sided contour appearing in Figure 3, and to act in effect as a turnbutton when rotated from that overlying position. Immediately beneath the head 1 6a, however, there is a non-circular shank portion 1 6d which enters and locates in a matching end recess 15e in the part 15b of the locating member 15. The shank portion 1 6d is basically of square section fitting into a square recess so that the bolt may be lifted clear, turned through 90"and reinserted. More precisely, however, it has one pair of opposite sides conforming to the contour of the head 1 6a and the other pair of opposite sides of the same shape as the first pair and shown in dashed lines in Figure 3, to provide the required alternative fitting at right angles. The recess 15e is a diametral through slot extending between the flats 1 sic with side faces following the said dashed lines and so fitting the inserted shank portion 16d.

The bolt stem 16b is a close sliding and rotational fit in the locating member 15. In order to ease manufacture, the stem-receptive bore in the locating member is of stepped diameter as shown in Figure 4 to provide separated upper and lower bearing surfaces.

The assembly 14 comprising of the locating member 15 and the bolt 16 has a retracted position between the guide plates 13 as shown in Figure 4. It can be lifted as a whole, by means of the handle 18, until the enlarged portion 15 clears the guide plates, and then rotated through 900to the operative position shown in Figure 1 in which the enlarged portion 15 bridges and seats upon the upper end faces of the guide plates. When a container has been positioned over the twistlock, as will be described, the tee-headed bolt 15 is lifted clear, rotated through 90"and re-seated to secure the container, the twistlock then being in the condition shown in Figure 2 ready for clamping by rotating the handle 18 to bring the collar 17 against the under faces of the guide plates 13 and to pull the whole assembly 14 downwardly.

To secure an I.S.O. container in position on the platform of a freight vehicle fitted with a plurality of twistlocks, the twistlocks are positioned as described in Specification No.

1,419,943 with the locating members and locking bolts in the raised operative position shown in Figure 1. The container is then lowered so that the heads of the locking bolts and the nose portions of the locating members 15 enter the openings in the corner castings of the container, the heads serving as guidance elements during final lowering movement of the container upon the nose portions of the locating members 15 for accurate positioning of the container.

After the container has been lowered, the vehicle can be driven from the loading station and then each locking bolt is moved into its locking position. This is effected by lifting the bolt by means of the handle so that the interengaging formations 16d and 15e of the bolt and locating member are disengaged. The bolt: is then turned throguht 90"and lowered whereupon the interengaging formations reengage and the twistlock comes to the condition shown in Figure 2. Further turning of the handle is then effected to move the bolt axially relative to the collar 17, the collar engaging the undersurfaces of the side plates 10 of the mounting body so that the locating bolt is drawn downwardly clamping the container in position. The base of the container may not be completely flat but any normal uneveness is compensated for by axial movement of the locking bolts which provide for effective damping of each corner of the container.

When not required for use, the locating member is pulled down, against a travel-limiting bolt 21, so as to lie substantially wholly below the upper surface of the top plate 12 as shown in Figure 4. A slight protuberance is usually desirable but the part 15b can be made axially shorter, with a reduced depth of the slot recess 15e, so that the apex of the head 16 lies flush with the upper surface of the top plate 12.

WHAT WE CLAIM IS: 1. A twistlock comprising a stud for locating and fastening a superposed structure such as a freight container, wherein the stud is slidable from a retracted position within a mounting and can then be turned to seat upon the mounting, the stud having a through bolt with a head which caps the stud, which bolt can be raised and turned to orient the head for locking, characterised by a manually operable nut or collar screwing on the lower end of the bolt stem and rotatable to abut the stud and also, in the raised position of the stud, to abut the mounting, thereby serving as a manipulative element for retracting, raising and turning the stud and bolt as a unit with the nut or collar screwed against the stud, for raising and turning the bolt with respect to the stud with the nut or collar unscrewed from the stud and for tightening the fastening by rotation of the nut or collar against the mounting.

2. A twistlock according to Claim 1, wherein the bolt head has a formation engaging in the stud to prevent relative rotation when lowered thereupon in the locking orientation and also in the non-locking orientation.

3. A twistlock according to Claim 1 or 2, wherein the mounting body comprises a backplate, and apertured top plate and two side plates between which the assembly is slidable, the locating member comprising a lower cylindrical stem portion, which is a free sliding fit between the guide plates, and an enlarged upper end portion which is effective for container location and is also freely slidable between the guide plates when within the mounting body.

4. A twistlock according to claim 3, wherein the enlarged upper end portion of the locating member has parallel flats in sliding relation to the guide plates and arcuate surfaces fitting in the top plate aperture.

5. A twistlock according to any one of the preceding claims, wherein the locating member has an upwardly facing nose capped by the domed head of the twistlock bolt, the bolt having immediately beneath the head a basically square shank portion fitting in a recess in the upper end face of the locating member, the bolt being movable clear of the recess and returnable after a 90" roataion into a locking position.

6. A twistlock according to claim 5, wherein the nose is tapered and the bolt head precisely overlies the tapered nose and moves to an overlapping locking position when the bolt is rotated.

7. A twistlock according to claim 6, wherein the basically square shank portion to the sides of the bolt head and conforms to the shape thereof.

8. A twistlock according to any one of the preceding claims, wherein the locating member has an axial bore for receiving the locking bolt, which bore is of stepped diameter to provide separate upper and lower bearings for the locking bolt.

9. A twistlock substantially as herein described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. undersurfaces of the side plates 10 of the mounting body so that the locating bolt is drawn downwardly clamping the container in position. The base of the container may not be completely flat but any normal uneveness is compensated for by axial movement of the locking bolts which provide for effective damping of each corner of the container. When not required for use, the locating member is pulled down, against a travel-limiting bolt 21, so as to lie substantially wholly below the upper surface of the top plate 12 as shown in Figure 4. A slight protuberance is usually desirable but the part 15b can be made axially shorter, with a reduced depth of the slot recess 15e, so that the apex of the head 16 lies flush with the upper surface of the top plate 12. WHAT WE CLAIM IS:

1. A twistlock comprising a stud for locating and fastening a superposed structure such as a freight container, wherein the stud is slidable from a retracted position within a mounting and can then be turned to seat upon the mounting, the stud having a through bolt with a head which caps the stud, which bolt can be raised and turned to orient the head for locking, characterised by a manually operable nut or collar screwing on the lower end of the bolt stem and rotatable to abut the stud and also, in the raised position of the stud, to abut the mounting, thereby serving as a manipulative element for retracting, raising and turning the stud and bolt as a unit with the nut or collar screwed against the stud, for raising and turning the bolt with respect to the stud with the nut or collar unscrewed from the stud and for tightening the fastening by rotation of the nut or collar against the mounting.

2. A twistlock according to Claim 1, wherein the bolt head has a formation engaging in the stud to prevent relative rotation when lowered thereupon in the locking orientation and also in the non-locking orientation.

3. A twistlock according to Claim 1 or 2, wherein the mounting body comprises a backplate, and apertured top plate and two side plates between which the assembly is slidable, the locating member comprising a lower cylindrical stem portion, which is a free sliding fit between the guide plates, and an enlarged upper end portion which is effective for container location and is also freely slidable between the guide plates when within the mounting body.

4. A twistlock according to claim 3, wherein the enlarged upper end portion of the locating member has parallel flats in sliding relation to the guide plates and arcuate surfaces fitting in the top plate aperture.

5. A twistlock according to any one of the preceding claims, wherein the locating member has an upwardly facing nose capped by the domed head of the twistlock bolt, the bolt having immediately beneath the head a basically square shank portion fitting in a recess in the upper end face of the locating member, the bolt being movable clear of the recess and returnable after a 90" roataion into a locking position.

6. A twistlock according to claim 5, wherein the nose is tapered and the bolt head precisely overlies the tapered nose and moves to an overlapping locking position when the bolt is rotated.

7. A twistlock according to claim 6, wherein the basically square shank portion to the sides of the bolt head and conforms to the shape thereof.

8. A twistlock according to any one of the preceding claims, wherein the locating member has an axial bore for receiving the locking bolt, which bore is of stepped diameter to provide separate upper and lower bearings for the locking bolt.

9. A twistlock substantially as herein described with reference to the accompanying drawings.