AU742736B2

AU742736B2 - Retractable corner casting fastener

Info

Publication number: AU742736B2
Application number: AU26951/99A
Authority: AU
Inventors: Ture Nyholm
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-05-05
Filing date: 1999-05-05
Publication date: 2002-01-10
Anticipated expiration: 2019-05-05
Also published as: AU2695199A

Description

4 P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

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55. Name of Applicant: Actual Inventor(s): Address for Service: Invention Title: TO BE COMPLETED BY APPLICANT TURE NYHOLM TURE NYHOLM A.P.T. Patent and Trade Mark Attorneys GPO Box 772, Adelaide, SA 5001 RETRACTABLE CORNER CASTING FASTENER Details of Associated Provisional Application Nos PP3341 dated 5th May 1998 PP4456 dated 2nd July 1998 The following statement is a full description of this invention, including the best method of performing it known to me:- The present invention relates to a corner casting fastener for fastening a container to a transport vehicle surface. Common forms of corner casting fasteners include twistlocks and hooks.

BACKGROUND OF THE INVENTION Transport of goods has become considerably standardised in recent times, with many goods being transported in shipping containers conforming to ISO regulations (International Standards Organisation). Such containers are beneficial in that the containers themselves can easily be handled, and may be readily transferred from one vehicle to another, and may thus be transported and fastened to a ship, a train or an articulated road vehicle. The containers are readily lifted by a crane from one transport vehicle to another.

The containers have corner castings, which are a hollow casting with apertures through three exposed surfaces, and which can engage fastening devices known as twistlocks or in the alternative hook arrangements. Such corner casting fasteners can be used to fasten the S•containers to the surface of the transport vehicle, or can be used to fasten containers one on top of the other when a stack of containers is formed. Other fasteners such as lashings may be needed in addition to the corner casting fasteners if the conditions are likely to be unstable such as on a ship.

In many instances such as shipping, the transport vehicle is specifically designed to transport goods only in containers. Corner casting fasteners may thus be fixed in position on the deck of a ship. In some instances however the vehicle may be desired to be used for a number of different uses, for example it may be desired to be used for loads other than in containers and in those circumstances it is not possible to have the corner casting fasteners fixed in position, because the corner casting fasteners protrude above the usual loading surface and interfere with efficient stacking of the goods. It is thus practice to provide suitable castings on the surface of, for example rail trucks, so that corner casting fasteners can be fitted to the truck, and then containers may be loaded on and the corner casting fasteners fasten the containers to the trucks.

This latter practice is however quite time consuming, and detracts from the efficiency of interchange between transport vehicle. It is proposed by the present invention to provide a retractable corner casting fastener that can be maintained in position, and that may be automatically retractable on the application of a load, unless a standard corner casting aperture presents itself, whereupon it engages into the comer casting and fastens the container onto the corner casting fastener.

OBJECT OF THE INVENTION It is an object of the present invention to provide a retractable corner casting fastener that obviates or minimises any one or more of the above problems, or at least provides the public with a useful choice.

SUMMARY OF THE INVENTION In a broad form and not necessarily the broadest or only form the invention could be said to reside in a retractable corner casting fastener including an elongate fastener head fixed on top of a vertically slidable inner housing together forming an inner body which is slidable inside a vertically aligned tubular bore of an outer housing, said slidable inner housing being substantially fixed about its 15 longitudinal axis, S. first biasing means, biasing the inner housing to a top of the tubular bore whereby said fastener head protrudes out of the tubular bore sufficiently for engagement with a corner casting of a container, whereby a first force is required to force entry of the fastening head into a slot within an aligned corner casting of a container, and whereby the first force is less than a second force required to retract the fastening head and inner housing, so that the fastening head enters the corner casting if properly aligned, and the fastening head is retracted if a floor of a container bears down on the fastening head.

Preferably the first biasing means is a compression spring bearing against a base of the outer housing, and the sliding inner housing and preferably out of contact with the shaft.

Preferably a sliding stop is provided limiting the extent of retraction of the shaft and fastener head.

The fastener head may of any suitable type that is adapted to fasten containers to the surface of a transport vehicle, or can be used to fasten containers one on top of the other when a stack of containers is formed.

In one form the corner casting fastener is a twistlock and the fastening head is an elongate cone fixed on to a vertically aligned shaft journalled for rotation within the inner housing the cone and shaft being rotatable between a first rotatable position and a second rotatable position, torsion biasing means biasing the cone and shaft to the first rotatable position, the twistlock being positioned on the transport vehicle surface whereby the cone in the first position is aligned at an angle to the slot within the corner casting.

Preferably an upwardly facing surface of the cone includes a sloping surface which slopes inwardly so that when an edge of the slot of the corner casting is engaged, the slope of the cone deflects the shaft to rotate. Preferably two of such sloping surfaces are provided, each diagonally opposed with respect to one another.

Preferably the torsion biasing means comprises an elastomeric block fastened to the shaft at an inner part and to the inner housing at an outer part, to act as a means to provide torsion against twisting of the shaft and cone relative to the inner housing.

oo a S0. Preferably the twistlock is fully automatic, whereby diagonally opposed downwardly facing surfaces of a lower part of the cone are oppositely, and outwardly inclined to the horizontal and vertical such that application of an upwardly lifting force exerts a torsional force whereby to twist the cone into alignment with the key plate aperture.

o. It may also be desired to provide a stop to limit the extent of rotation of the shaft and the cone.

In an alternative form the fastener may be a hook fastener and the fastening head comprises a hook body being generally rectangular in cross section and configured to pass into the slot of a corner casting, at least one side of the hook body including a protrusion tapering outward as said protrusion extends downwards, apart from a lowermost end portion which tapers abruptly inwardly, so that the protrusion bears against an elongate side of the corner casting to a degree requiring the first force to force entry into the corner casting.

It is to be understood that the invention could also be said to reside in a vehicle including a twistlock as defined or described herein.

To assist with the understanding of the invention two embodiments are illustrated. It is to be understood from the foregoing that the illustrated embodiments of the invention are merely illustrative and in no way restrict the scope of the invention.

BRIEF DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS Figure 1 is a part cross sectional view through 1-1 (Figure 5) of the twistlock when fitted to a railway carriage with the cone in its fully extended position, and the cone in a first position ready for retraction into the tubular bore, Figure 2 is a schematic view of a similar cross sectional aspect as Figure 1 longitudinally through the twistlock showing the cone in the retracted position, Figure 3 is a part cross sectional view through 3-3 (Figure 6) of the twistlock when fitted to the railway carriage with the cone in its fully extended S•position, with the cone rotated in a second position, such that it is o 15 blocked from entering into the tubular bore, Figure 4 is a longitudinal cross sectional view of the outer housing, showing the facility to insert the torsional biasing means, Figure 5 is a view from above showing the alignment of the elongate cone with an aperture of the corner casting, the key plate aperture, with the cone being in the second position, where retraction is blocked, Figure 6 is a view from above showing the alignment of the elongate cone with an aperture of the corner casting, the key plate aperture, with the cone being in the first rotational position with retraction being enabled, Figure 7. shows a plan view from above of the rubber spring as keyed onto the shaft, Figure 8 shows a plan view from above of a second embodiment of the rubber spring as engaged with the shaft, Figure 9 shows a cross sectional side view through 9-9 of Figure 8, of a second embodiment of the rubber spring, Figure 10 is a side partial cross sectional view of a second embodiment of the invention, and Figure 11 is a front partial cross sectional view of the second embodiment.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS Similar reference characters indicate corresponding parts throughout the several views of the drawings.

Dimensions of certain of the parts as shown in the drawings may have been modified and/or exaggerated for the purposes of clarity of illustration.

The illustration show two embodiments of corner casting fasteners, with Figure 1 to 9 S. "showing a twistlock fastener and Figures 10 and 11 showing a hook fastener.

15 Turning now to the embodiment illustrated in Figures 1 to 9.

The illustrated retractable corner casting fastener is in the form of a retractable twistlock S"comprising an elongate cone for engagement with a corner casting of a container.

S• The elongate cone is fixed to the top of a vertically aligned shaft which shaft is journalled for rotation within a slidable inner housing The cone, shaft and inner **housing could be said to comprise an inner body. The slidable inner housing is substantially fixed about its longitudinal axis. A first biasing means comprises two helically wound springs 6) each wound in a direction opposite one to the other to maintain balance in the retraction. The two helically wound springs bear against a lower part of the slidable inner housing and against the inside of a base of the outer housing, to bias the inner housing, cone and shaft to a top of the tubular bore formed within the outer housing The top of the tubular bore is covered by a plate which has an aperture (12) passing therethrough. In a first extended position the inner housing is biased to a top of the tubular bore, an upwardly facing surface of the inner housing (13) bearing against a lower surface (14) of the plate In this extended position the cone extends beyond the plate to an extent such that it can engage with the corner casting of a container. An upper portion (15) of the inner housing is elongate having similar cross sectional dimension to the cone so that it can pass through the aperture (12) as well as through apertures in the corner casting. The upper portion (15) also extends beyond the plate to an extent of a little more than the thickness of a lower wall of the corner casting. The upper portion (15) of the inner housing is substantially fixed rotationally about a vertical axis, and is therefore always aligned for passage through the plate aperture.

A torsional biasing means biases the shaft and the cone in a first position as shown in Figures 1, 2 and 5. As best seen in Figure 7, the torsional biasing means comprises a flat block (18) of rubber, which is fused to an inner metal ring (19) which ring is keyed onto shaft by a key (16) which keys into a vertical groove (17) in the shaft. A plurality of holes (20) are drilled through the block, and the size of the torsional effect can be adjusted by the number, size and shape of the holes as well as the nature of the rubber.

A second embodiment of the torsional biasing means is illustrated in Figures 8 and 9. The rubber block is round and a second metal ring (50) surrounds the generally round rubber block. A threaded aperture is formed in the housing and a bore (51) is formed circumferentially into the outer metal ring, so that a dog screw (52) can be passed through 15 the aperture in the housing and fastened therethrough to engage the bore in the metal ring.

9**9 This configuration simplifies removal of the biasing means where desired. All that is required is unscrewing of the dog screw and to slide out the rubber ring. It is to be noted also that no keyway or corresponding key is provided to lock the biasing means into position, instead an axially elongate flat face is provided on the shaft, and a complementary flat is provided on the inner metal ring (19) to engage the flat of the shaft.

9" The biasing of the cone into the first position enables the elongate cone to pass through the plate aperture as best seen in Figure 6, where force has been applied the cone can be *pushed down so as to take on a retracted position as shown in Figure 2.

In the illustrated embodiment, diagonally opposite parts (23, 24) of side edges (22) of the lower aperture (36) of the corner casting bear against corresponding sloping upper surfaces (25, 26) of the cone. As these bear down carrying the weight of the container with or without its contents the cone will twist to the second position.

The bias of the helical springs is much greater than the bias of the rubber block, thus the cone if engaged with side edges of the lower aperture of the corner casting, the cone will twist to the second position rather than retract directly into the tubular housing.

Where no corner casting is present, and the flat bottom of a container bears down on the cone, the twistlock simply retracts back into the vertical bore, the cone ending up flush with the key plate as can be seen in Figure 2.

The journal about which the shaft is secured from the base, extends upwardly as a cylindrical body An upper surface of the cylindrical body can act as a stop to ensure that the cone does not get forced too low, which otherwise might result in jamming.

The present embodiment further facilitate use of these twistlocks, in that it is fully automatic. Thus no manual intervention is required to place the container on the twistlocks or to lift off the container. Diagonally disposed sloping surfaces (30, 31) are positioned to bear against the edges of the comer casting when a lifting force is exerted, and thereby twist the cone and shaft into the first position. The edges (23, 24) of the corner casting only act against the rubber block, and do not bear down onto the coil springs A sufficient force is able to rotate the cone into the first position so that the container can be lifted from the several twistlocks attached to the particular container and truck.

The present embodiment also has provision for an indicator (40) which may be brightly 15 coloured to give an indication of the position of the cone by inspection from underneath the carriage. The indicator is connected to a lower part of the shaft.

With the fully automatic twistlock it is not intended that one container be stacked on top S•another, and it is not intended that these twistlocks are to be used in shipping because the forces impacting on the container and twistlock connection are such that the container may be dislodged during transport.

A second embodiment of the invention is shown in Figures 10 and 11. The constructional details of these is quite similar to that of the first embodiment, except that the comer casting fastener is a hook in place of a twistlock. The second embodiment has no torsional biasing means nor is the fastening head rotatable. It is to be understood that the use of a hook for fastening to a corner casting of a shipping container is known, and the invention is intended to include any variation of hook that is currently known or may become known that is adapted to the present means of retraction.

The aperture (12) through plate (11) is shaped to coincide with the horizontal cross sectional dimension of the hook so that the hook can readily pass therethrough should the force of the container bear downwardly thereon against spring (42) shown in part only. The spring can be of the same configuration as that of the first embodiment whereby two helical springs are employed.

The hook in the present embodiment is fixed to the inner housing and shaft, all of which are generally not rotatable relative to the outer housing The hook (41) is generally rectangular in horizontal cross section and of dimensions to fit into the slot of a standard ISO shipping container comer casting. The hook extends upwardly from the inner housing, and a side protrusion (43) extends from one side face (44) of the hook. The side protrusion tapers outwardly when extending downwardly on the side face, whereby to require the exertion of some force to enter the corner casting. It will be understood that the degree to which the protrusion extends determines the force required. A lower portion of the protrusion tapers abruptly back to the side face of the hook, and it can be seen that this taper is slightly curved. The removal of the hook from the corner casting again requires some force to squeeze the hook through the slot of the corner casting.

.ooooi As with the first embodiment, if a container is loaded directly onto the hook, the hook will retract into the bore and a substantially flush surface is provided for the underside of the 15 container. If the slot of a comer casting is aligned with the hook then the hook can be forced into the comer casting to engage therewith.

Various features of the invention have been particularly shown and described in connection with the exemplified embodiment of the invention, however, it must be understood that these particular arrangements merely illustrate and that the invention is not limited thereto and can include various modifications falling within the spirit and scope of the invention.

Claims

1. A retractable corner casting fastener including an elongate fastener head fixed on top of a vertically slidable inner housing together forming an inner body which is slidable inside a vertically aligned tubular bore of an outer housing, said slidable inner housing being substantially fixed about its longitudinal axis, first biasing means, biasing the inner housing to a top of the tubular bore whereby said fastener head protrudes out of the tubular bore sufficiently for engagement with a corner casting of a container, whereby a first force is required to force entry of the fastening head into a slot within an aligned comer casting of a container, and whereby the first force is less than a second force required to retract the fastening head and inner housing, so that the fastening head enters the comer casting if 15 properly aligned, and the fastening head is retracted if a floor of a container bears down on the fastening head.

2. A retractable corner casting fastener according to claim 1 wherein the first biasing means is a compression spring bearing against a base of the outer housing and the sliding inner housing.

3. A retractable corner casting fastener according to claim 1 wherein the first biasing means comprises two helically wound compression springs each bearing against a •base of the outer housing and the sliding inner housing, and each wound in a direction opposite one to the other to maintain balance in the retraction.

4. A retractable corner casting fastener according to either claim 2 or claim 3 wherein a sliding stop is provided limiting the extent of retraction of the fastener head and inner housing.

A retractable corner casting fastener according to claim 4 wherein the top of the tubular bore is covered by a plate which has an aperture passing therethrough such that when the inner housing is biased to a top of the tubular bore, an upwardly facing surface of the inner housing bears against a lower surface of the plate to thereby act as a stop against further upward movement of the inner housing, the fastener head extending beyond the plate to an extent such that it can engage with the corner casting of a container. 11

6. A retractable corner casting fastener according to claim 5 wherein an upper portion of the inner housing is elongate and has similar cross sectional dimension to the fastener head so that upper portion of the inner housing can pass through the aperture as well as through the slot in the corner casting.

7. A retractable corner casting fastener according to claim 6 wherein the upper portion of the inner housing extends beyond the plate to an extent that is slightly greater than the thickness of a lower wall of the corner casting.

8. A retractable corner casting fastener according to any one of the preceding claims wherein the corner casting fastener is a twistlock and the fastening head is an elongate cone fixed on to a vertically aligned shaft journalled for rotation within the inner :housing, the cone and shaft being rotatable between a first rotatable position and a second rotatable position, torsion biasing means biasing the cone and shaft to the first rotatable S. position, the twistlock being positioned on the transport vehicle surface whereby the cone in the first position is aligned at an angle to the slot within the corner casting.

9. A retractable corner casting fastener according to claim 8 wherein an upwardly facing surface of the cone includes at least one sloping surface sloping inwardly so that when an edge of the aperture of the corner casting is engaged, the slope of the cone deflects the cone and shaft to rotate.

10. A retractable corner casting fastener according to claim 9 wherein two sloping surfaces are provided on the upwardly facing surface, each of the sloping surfaces being diagonally opposed with respect to one another.

11. A retractable corner casting fastener according to claim 10 wherein the torsion biasing means comprises an elastomeric block fastened to the shaft at an inner part and to the inner housing at an outer part, to act as a means to provide torsion against twisting of the shaft and cone relative to the inner housing.

12. A retractable corner casting fastener according to claim 11 wherein the torsion biasing means comprises a flat block of rubber which is attached to the inner housing and is fused to an inner metal ring, which ring is keyed onto the shaft by a key which keys into a vertical groove in the shaft. 12

13. A retractable comer casting fastener according to claim 12 wherein a plurality of holes are drilled through the block, and the size of the torsional bias can be adjusted by the number, size and shape of the holes as well as the nature of the rubber.

14. A retractable corner casting fastener according to claim 11 wherein the torsion biasing means comprises a flat block of rubber which is fused to an inner metal ring and fused to an outer metal ring, the outer metal ring having a bore for alignment with a screw threaded aperture in the inner housing so that a screw can be passed through the aperture in the housing and fastened therethrough to engage the bore in the metal ring, and the inner metal ring having a flat section to engage an axially elongate flat face on the shaft. A retractable corner casting fastener according to any one of claims 8 to 14 Swherein the twistlock is fully automatic, whereby diagonally opposed downwardly facing surfaces of a lower part of the cone are oppositely, and outwardly inclined to the horizontal o 15 and vertical such that application of an upwardly lifting force exerts a torsional force o. whereby to twist the cone into alignment with the slot in the corner casting.

S•

16. A retractable corner casting fastener according to any one of claims 8 to wherein a stop is provided to limit the extent of rotation of the shaft and the cone.

•17. A retractable comer casting fastener according to claim 16 wherein an indicator is connected to a lower part of the shaft such that the indicator gives an indication of the position of the cone by inspection from underneath the load surface.

18. A retractable corner casting fastener according to any one of claims 1 to 7 wherein the fastener is a hook fastener and the fastening head comprises a hook body being generally rectangular in cross section and configured to pass into the slot of a comer casting, and to one or both elongate side including a protrusion tapering outward as said protrusion extends downwards, apart from a lowermost end portion which tapers abruptly inwardly, so that the protrusion bears against an elongate side of the corner casting to a degree requiring the first force to force entry into the corner casting. 13

19. A retractable corer casting fastener substantially as herein described with reference to the accompanying illustrations. A vehicle including a retractable corer casting fastener as defined or described herein. Dated this 5th day of May 1999 TURE NYHOLM By his Patent Attorneys A.P.T. Patent and Trade Mark Attorneys S S. S