AU2014265039B2

AU2014265039B2 - Twistlock having a shaft with retaining protrusions

Info

Publication number: AU2014265039B2
Application number: AU2014265039A
Authority: AU
Inventors: Ture Nyholm
Original assignee: Skrin Pty Ltd
Current assignee: Skrin Pty Ltd
Priority date: 2013-12-05
Filing date: 2014-11-19
Publication date: 2017-06-15
Anticipated expiration: 2034-11-19
Also published as: NZ629714A; AU2014265039A1

Abstract

A twistlock comprising a housing and a shaft supported for rotation by the housing, a cone extending upwardly of the housing for engagement with a corner casting of a 5 shipping container, the cone integrally formed with the shaft. The shaft insertable into a top of the housing and retained therein by pairing an upwardly facing retention surface of the shaft and a downwardly facing retention surface of the housing. The twistlock may have a biasing means to bias the shaft and cone into the engaging position of a working range, the biasing means being fixed to the housing after the 10 shaft is fitted and rotated into the working rotation range to thereby maintain the shaft in the working rotation range and unlined with recesses for removal of the shaft from the housing. Figure 1 Figure 2

Description

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PROVISIONAL SPECIFICATION FOR AN INVENTION ENTITLED

Invention title:

Twistlock having a shaft with retaining protrusions

Name of Applicant: Skrin Pty Ltd

Address for Service A.P.T. Patent and Trade Mark Attorneys PC Box 222 Mitcham, S.A. 5062

The invention is described in the following statement ο (Ν > Ο σ^ σ^ m ο Ό (Ν Ο (Ν

Twistlock having a shaft with retaining protrusions FIELD OF THE INVENTION

This invention relates to a twistlock of the type used for securing a shipping container 5 to a load surface.

BACKGROUND OF THE INVENTION

Transport of goods has become standardised, with many goods being transported in shipping containers conforming to ISO (International Standards Organisation) 10 standards. The use of such containers is beneficial in that the containers themselves can easily be handled and may be readily transferred from one vehicle to another by way of a crane, such as wharf based gantry cranes or other lifting device.

This means that the contents of the shipping container, notwithstanding one or more 15 transfers, are typically not unloaded until the container reaches its final destination. The shipping containers are attached to various load surfaces during transportation such as ships, rail trucks and articulated road vehicle.

The shipping containers include corner castings, which are hollow castings having a 20 slot therethrough to engage fastening devices known as twistlocks that may be mounted to the load surface. The twistlocks can be used to fasten the containers to the load-bearing surface of the transport vehicle such as a railway truck.

In rail applications twistlocks have a height limitation. Standards for the height of 25 twistlocks take into account the minimum clearance allowed for bridges traversing a rail track. Thus the twistlocks for rail transport are low profile, in Australia the prescribed clearance from the rail truck surface to the bottom of the container is 28mm. 30 Typically twistlocks include a housing and a cone extending upwardly from the housing for engagement with a corner casting of a shipping container, the cone being integral with a shaft supported for rotation by the housing. Rotation of the shaft permits engagement and disengagement of the cone via the slot with the corner casting. The shafts of many twistlocks include a threaded end extending from ο (Ν > Ο 2; σ^ σ^ m ο Ό (Ν Ο (Ν 10 underneath of the housing. A fastener, in the form of a nut is fastened to the threaded end of the shaft to secure the shaft to the housing.

Assembly and disassembly of such prior art twistlocks, for example, for replacement of worn parts or for service, requires access to both the top and bottom of the housing of the twistlock, and this is often not available or awkward when the twistlocks are permanently mounted. Accordingly to remove the shaft and cone a user is required to unfasten the nut holding the cone in place before sliding the shaft out of the top of the housing.

Furthermore there are tight tolerances for attachment of the shaft nut to ensure that there is no impediment to rotation of the shaft by undue friction of the nut, or washer on the housing or that the nut does not become loose. 15 It will also be appreciated that by providing a fastener such as a nut under the housing raises the height of the twistlock, if only by the height of the nut, whether or not it is accommodated in the housing, but given the tight restriction of twistlocks for use in rail applications this is significant.

20 SUMMARY OF THE INVENTION

In one form of a first aspect the invention provides a twistlock comprising a housing and a shaft supported for rotation by the housing, a cone extending upwardly of the housing for engagement with a corner casting of a shipping container, the cone 25 integrally formed with the shaft, the shaft insertable into a top of the housing and retained therein by pairing an upwardly facing retention surface of the shaft and a downwardly facing retention surface of the housing. 30 In a second form of the first aspect, the invention provides a twistlock for reversibly engaging with a corner casting of a shipping container to fasten the shipping container on a load surface, the twistlock comprising, a housing having a top and a bottom, the bottom connected or adapted for connection with a load surface, ο (Ν > Ο σ^ σ^ m ο Ό (Ν Ο (Ν 10 15 20 25 an upright shaft having a corner casting engaging cone on top, the shaft being rotatable between an engaging position and a disengaging position of the cone, the cone being elongate laterally with respect to the shaft and being in the disengaged position aligned with a slot in a corner casting in which position it can fit through the corner casting, and in the engaged position being angled with respect to the slot so that when positioned therein an underneath surface of the cone engages with upwardly facing surfaces inside the corner casting to retain the container on the load surface, the shaft biased to the engaged position by a biasing means the shaft comprising at least one retaining protrusion having an upwardly facing retention surface paired with a downwardly facing internal retention surface of said housing to retain the shaft in the housing.

Preferably the shaft is rotated in order to pair the upwardly facing retention surface of the shaft with the downwardly facing retention surface of the housing.

The twistlock preferably further comprising removeable stop means to inhibit rotation of the shaft for unpairing of the opposed retention surfaces.

In an alternative the downwardly facing retention surface of the housing is slid into place, the downwardly facing retention surface being removable from the housing.

Preferably the upwardly facing retention surface is on a radial protrusion of the shaft. The downwardly facing retention surface may be on an overhang in a cavity in the housing.

In the converse alternative the upwardly facing retention surface is within a groove in the shaft and the downwardly facing retention surface may be part of a protrusion extending from the housing into the groove in the shaft. 30 Preferably an insertion recess extends between the cavity and the top of the housing, the recess accommodating the protrusion, to allow for insertion of the shaft and protrusion. ο (Ν > Ο σ^

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Preferably the protrusion does not align with the insertion recess when the shaft is within the working rotation range, being at or between the engaging and disengaging position. 5 In one form stop means are provided to prevent rotation beyond the engaging and disengaging positions.

In an alternative the biasing means is fixed to the housing after the shaft is fitted and rotated into the working rotation range, and this inhibits rotation beyond the engaging 10 and disengaging positions

The protrusion preferably has a flat upwardly facing retention surface that bears against the downwardly facing retention surface, thereby acting as a bearing when the shaft and housing are rotated relative to one another. 15

Preferably there are a plurality of protrusions on the shaft and these are preferably opposed. Reference to opposed means that they provide a balance, for example, where there are two these may be positioned 180° if there are three, then 120°. 20 With more than one protrusion there will be more than one insertion recess. Most preferably there are two protrusions and two insertion recesses.

Preferably the protrusions are positioned above the biasing means so that only the shaft need be accommodated by the biasing means. Less preferable forms of the 25 invention provide for the protrusions below the biasing means and include in the biasing means an accommodation of the passage of the one or more protrusions. In this form the retaining protrusions may be positioned adjacent the lower end of the shaft and configured to engage with an engagement member positioned at a lower part of the body portion. In this form the biasing means may be shaped to permit 30 passage of the shaft and retaining protrusion therethrough wherein a part of the biasing means engages with the shaft at a position intermediate of the cone and retaining protrusion. ο (Ν > Ο σ^ σ^ m ο Ό (Ν Ο (Ν 10

In one form the retaining protrusions have a generally rectangular top cross-sectional profile and extend radially outwardly of the shaft. The shaft preferably has two retaining protrusions extending outwardly from opposing sides of the shaft. It will be understood that multiple retaining protrusions may be positioned around the shaft that bear against respective downwardly facing surfaces of the housing.

The housing may include a passageway for receiving the shaft therethrough, the passageway extending between an upper surface of the housing and a chamber that holds the biasing means. The upper surfaces of the retaining protrusions form a shoulder that is configured to engage against a downwardly facing surface of the housing. In one form the downwardly facing surfaces are overhanging rim portions that extend around a part of the edge of the passageway on opposing sides.

The passageway may be generally elongate and include one or more recesses on 15 opposing sides for receiving the retaining protrusions therethrough, the recesses being intermediate of the overhanging rim portions. In this way the shaft may be positioned so that it can be inserted through the passageway whereby the retaining protrusions pass through the recesses. Once the upper surfaces of the retaining protrusions are below the overhanging rim portions the shaft may be rotated such 20 that the retaining protrusions engage with said rim portions.

In one form the biasing means biases the protrusions from aligning with the recesses so that once the biasing means is connected to the shaft the retaining protrusions are inhibited from aligning with the recesses. This therefore inhibits disengagement of 25 the shaft from the housing due to the fact that the spring limits the rotation of the shaft. To remove the shaft the biasing means is disconnected from the shaft to allow or the alignment of the retaining protrusions with the recesses to thereby enable the shaft to be withdrawn from within the body portion. As an alternative or in addition a removable stop limit means, for example, a pin may interact with a cavity in the shaft 30 or in the alternative the housing to limit rotation. The stop limit means thus needs to be removed for removal of the shaft from the housing.

The two retaining protrusions in one form of this invention engage with respective rim portions that are located at an upper part of the chamber of said body portion. In this ο (Ν > Ο σ^ σ^ m ο Ό (Ν Ο (Ν 10 20 25 30 7 form the biasing means engages with the shaft at a position between a lower edge of the retaining protrusions and the free end of the shaft.

The upper part of the shaft is preferably journalled for rotation about an upper bearing formed in the upper part of the housing, and the cavity is formed in the housing adjacent the upper bearing, so that the downwardly facing retention surface is formed adjacent the upper bearing, the upper bearing and the downwardly facing retention surface being interrupted by the one or more insertion recesses. Thus the downwardly facing retention surfaces will be formed as one bearing surface and the recesses divide this into the two or more parts. It will be understood that in this embodiment the one or more upwardly facing retaining surfaces are co-planar for rotation on the downwardly facing bearing surface.

This provide for a compact bearing arrangement, with two adjacent bearing surface 15 at right angles to one another at the upper part of the twistlock housing immediately adjacent the source of the force acting on the shaft.

Preferably a second bearing is provided at a lower end of the shaft, the lower end of the shaft is journalled for rotation in a bearing at a lowermost part of the housing. The shaft has a circular cross-section with a correspondingly shaped bore in the bottom of the housing to form a lower bearing

Accordingly the upper surface of the retaining protrusions and upper portion of the shaft form a first bearing surface and the lower end of the shaft forms a second bearing surface. The use of two spaced-apart bearing surfaces providing greater stability to the shaft.

The biasing means is preferably positioned between the upper bearing arrangement and the lower bearing so that shaft bearings are located top and bottom of the biasing means.

The biasing means is preferably flat. Where the biasing means comprises an elastomeric block this will therefore be flat, perhaps in the form of a disc. This may comprise a internal metal ring that the shaft can be slid into. Preferably the shaft 8 ο (Ν > Ο σ^ σ^ m ο Ό (Ν Ο (Ν 10 15 20 includes a flattened portion and the internal metal ring include a complementary shaped flat portion so that the shaft and metal ring are keyed together for rotation, the elastomeric block is similarly fused to an external metal ring the comprises as means for receiving a fastener that connects the external metal ring with the housing. Such a flat block, it will be understood, is vertically compact and as a result is particularly suited for rail applications. The biasing means may alternatively be a spring steel activator comprising a first end that is fitted into a socket in the shaft, and a second end that is fixed to the housing, with a coil therebetween to bias the shaft into the engaged position The twistlock may be mounted directly onto the load surface by way of bolt or other fasteners, however preferably the twistlock is attached to a base plate that is fixed to the load surface by way of, but not limited to bolts, clamps or welds. The twistlock may be slidably attached to the base plate and secured by way of locking pins or bolts, such that the twistlock can be removed from the load surface when not in use. Alternatively the twistlock may be of the type that can be shifted beneath the load surface when not needed for example it may be retractable, or it may be foldable, being held on a carrier that can pivot below the load surface when not in use. The twistlock may be an automatic, semiautomatic or manual twistlock. The cone is preferably integral with the shaft.

The invention may also be said to reside in a vehicle whether towable, such as a 25 railway carriage, or self motive, such as with a truck, with a twistlock arrangement of the first aspect of the invention. BRIEF DESCRIPTION OF THE DRAWINGS 30 The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate implementations of the invention and, together with the description, serve to explain the advantages and principles of the invention. In the drawings. ο (Ν > Ο σ^ σ^ m Ο ΙΟ (Ν Ο (Ν 10 20 Figure 8

Figure 1 is a side view of a first embodiment of the shaft and cone of the twistlock of the present invention;

Figure 2 is a front view of a the shaft and cone of figure 1;

Figure 3 is a cross sectional view of the shaft of figure 1 through A-A;

Figure 4 is a top view of a first embodiment of the body portion for engagement with the shaft of figure 1;

Figure 5 is front cross-sectional view of the body portion of figure 4 illustrating the insertion of the shaft of figure 1;

Figure 6 is side cross-sectional view of the body portion of figure 4 illustrating 15 the rotation of the shaft therewithin for engagement with the overhanging rim;

Figure 7 is a front view of a second embodiment of the shaft and cone; is a cross sectional view of the shaft of figure 7 through B-B;

Figure 9a is a top view of body portion illustrating the relative position of the shaft being inserted into the passageway, with cone attached; 25 Figure 9b is a top view of the body portion of figure 9a illustrating the relative position of the shaft and cone when the shaft is engaged with the biasing member; and

Figure 9c is a top view of the body portion of figure 9a illustrating the working 30 angle of the shaft and cone between the engaging and disengaging positions relative to the corner casting of the shipping container.

DETAILED DESCRIPTION OF THE ILLUSTRATED AND EXEMPLIFIED EMBODIMENTS ο (Ν > Ο σ^ σ^ m ο Ό (Ν Ο (Ν 10 15 10

There are numerous specific details set forth in the following description. However, from the disclosure, it will be apparent to those skilled in the art that modifications and/or substitutions may be made without departing from the scope and spirit of the invention. In some circumstance specific details may have been omitted so as not to obscure the invention. Similar reference characters indicate corresponding parts throughout the drawings.

The illustrated embodiments show a twistlock 10 in connection with a load surface 12 (see Figure 5). The twistlock 10 includes a housing 14 and a cone 16. The cone 16 is formed on an exposed end of a shaft 18, which is journalled into the housing 14 so that the cone 16 can rotate. The cone 16 is rotatable relative to the housing 14 between an engaging position (see Figure 9b) and a disengaging position (see Figure 9c). When in the disengaging position the cone is aligned with a slot in a corner casting of a shipping container (not shown) such as one conforming to ISO standards. The cone is biased to the engaging position so that the twistlock maintains engagement with a corner casting unless specifically released.

The cone 16 may be attached to, or formed at, an end of the shaft 16. In the 20 illustrated embodiment the cone and shaft are integral. The shaft includes retaining protrusions 20, 22 for engagement with a downwardly facing surface of the housing 14 to thereby rotatably couple the shaft to said housing.

The cone 16 is elongate and is bevelled so that sides of the elongate slot in the 25 container corner casting when lowered thereonto can bear thereagainst to rotate the cone 16 and shaft from the engaging position to the disengaging position. The cone is biased into the engaging position by reason of a biasing means 24 acting on the shaft 18. 30 The illustrated embodiment includes a fully automatic twistlock wherein the lower portion of the twistlock is also bevelled so that when the cone is in the corner casting, sides of the elongate slot in the corner casting can bear against the bevelled lower portion to rotate the cone and shaft from the engaging position to the disengaging position. ο (Ν > Ο σ^ σ^ m ο Ό (Ν Ο (Ν 10 15 20 25 11

The extent of the bevel is matched with the bias exerted by the biasing member to provide sufficient resistance to rotation to prevent the container being dislodged during normal use, but there is not sufficient resistance to rotation to prevent the contain being lifted by a crane from the load surface. The precise angle of the bevel will depend on the nature and strength of the biasing means and may be empirically determined. The biasing member provides the majority of this resistance. A semi-automatic system whereby the bottom surface of the twistlock is not bevelled, but a lever or cable is manually or otherwise operated to turn the cone into the disengaged position before the container is lifted is also contemplated by the invention.

The housing 14 of the twistlock comprises essentially two parts, one such part is a central flat portion 26 that is supported by the load surface 12. Extending upwardly from the flat portion 26 is a slot engaging portion 28, which is shaped so as fit into the slot of the corner casting and engage therewith. The slot engaging portion 28 has a height which fits into the slot to such an extent whereby the lowermost surface of the cone 16 clears the thickness of the corner casting and accordingly can rotate to the engaging position when inside the hollow of the corner casting. The configuration of the slot engaging portion, and its relative position to the lowermost portion of the cone 16, and thickness of the wall of the corner casting is well known with various configurations of twistlocks. The biasing member is positioned within the flat portion 26 of the housing of the twistlock.

The housing of the twistlock is made in the normal manner, and is of generally unitary construction being cast in one piece.

The illustrated embodiment is a twistlock 10 for securing a shipping container to a 30 load surface 12, comprising housing 14, and cone 16 fixed to shaft 18, the cone 16 being rotatable, relative to the body portion, about a longitudinal axis of the shaft 18 between an engaging position and a disengaging position. The cone 16 is positioned on the load surface 12 for engagement with a corner casting of the shipping container (not shown). ο (Ν > Ο σ^ σ^ m ο Ό (Ν Ο (Ν 10 12

The housing 14 includes a chamber 30 for holding a biasing means 24 for biasing the rotation of the shaft 18 and the cone 16 into the engaging position. Retaining protrusions 20, 22 are configured to engage with respective surfaces 32, 34 that in the present embodiment are overhanging rims formed at an upper edge of the chamber 30, either side of a passageway 36 for permitting the insertion of the shaft 18.

The retaining protrusions 20, 22 may be generally rectangular wings extending radially outwardly of the shaft 18. As illustrated in figure 3 the shaft has a cylindrical shape with two retaining protrusions 20, 22 extending outwardly from opposing sides of the shaft 18.

The passageway 36 in the housing for receiving the shaft therethrough extends 15 between an upper surface of the housing and the chamber 30, as illustrated in figure 4. The upper surfaces of the retaining protrusions 20, 22 form shoulders that are configured to engage against downwardly facing surfaces 32, 34 of the housing 14. The downwardly facing surfaces may be considered as overhanging rim portions that extend around a part of the edge of passageway 36 on opposing sides, as illustrated 20 in figure 4.

The passageway 36 is generally elongate and includes insertion recesses 38, 40 on opposing sides for receiving the retaining protrusions 20, 22 therethrough. The recesses 38, 40 are intermediate of the overhanging rim portions 32, 34. As 25 illustrated in figure 5, in this way the shaft may be positioned so that it can be inserted in the direction of arrow 42 through the passageway 38 whereby the retaining protrusions 20, 22 pass through recesses 38, 40. Once the retaining protrusions 20, 22 are below the overhanging rim portions 32, 34, as illustrated in figure 6, the shaft 18 may be rotated in the direction of arrow 44 (see Figure 6) such 30 that the retaining protrusions engage with said rim portions.

As further illustrated in figure 6, the lower end 48 of the shaft 18 forms a lower bearing at a lower part of the housing 14. The shaft is circular in cross-section and engages with a correspondingly shaped bore in the bottom of the housing 30. ο (Ν > Ο σ^ σ^ m ο Ό (Ν Ο (Ν 13

An upper bearing is formed between the upper inside 90 of the housing and upper surface 91 of the shaft. This bearing is in two parts by reason of being interrupted by the two recesses 38, 40. 5

The retaining protrusions 20, 22 and upper portion of the shaft 18 form a thrust bearing surface, adjacent and at right angles to the upper bearing (90, 91).

The provision of two spaced-apart bearing surfaces therefore stabilised the shaft 10 under the quite considerable load that is imparted on disconnecting a container.

The shaft 18 in the illustrated embodiment is inhibited from disengagement from the housing 14 by connection with the biasing means 24 that limits the rotation of the shaft 18. Once the biasing means 24 is connected to the shaft 18 the retaining 15 protrusions 20, 22 are inhibited from aligning with recesses 38, 40, since alignment may result in the shaft disengaging form the housing. To remove the shaft 18 or to free a jammed cone the biasing means 24 is simply disconnected from the shaft 18. This permits free rotation of the shaft 18 and if required the alignment of the retaining protrusions 20, 22 with the recesses 38, 40. 20

As illustrated in the figures the retaining protrusions 20, 22 are flattened along a plane parallel to the longitudinal axis of the shaft 18 and are positioned at a mid portion of the shaft 18 between the junction 46 with the cone 16 and the lower end 48 of the shaft 18. 25

In the illustrated embodiment the two retaining protrusions 20, 22 engage with respective rim portions 32, 34 that are located at an upper region of the chamber 30. The biasing means 24 engages with the shaft 18 at a position between a lower edge of the retaining protrusions 20, 22 and the lower end 48 of the shaft as illustrated in 30 figure 6. This means that any type of biasing means could be used, such as, an elastomeric block that slidable engages the shaft or a spring steel member.

The elastomeric block may be flat disc as is known in the art or a spring steel device this is generally contained within the chamber 30. It is envisaged that the biasing ο (Ν > Ο σ^

σ^ m o Ό (N O (N 10 15 14 means will be vertically compact so that it is suitable for rail applications that has tight constraints in terms of allowable height of the twistlock in rail transport. However it should be appreciate that other biasing means could be used in other applications.

Although not illustrated in another embodiment the retaining protrusions may be positioned adjacent the lower end of the shaft and configured to engage with an engagement member positioned at lower end of the body portion. In such a form the biasing means may included a coiled portion that is shaped to permit passage of the shaft and retaining protrusion therethrough wherein a part of the biasing means engages with the shaft at a position intermediate of the cone and retaining protrusion.

The shaft 18 further includes a flattened keyway 80 whereby the biasing means may be a ring shaped elastomeric block that slidable engages the shaft 18. The elastomeric block being vulcanised to an internal bearing comprising an annual band that is engagable with a key for fixing the elastomeric block to the shaft.

The twistlock 10 may be mounted directly onto the load surface by way of bolt or other fasteners. However preferably the twistlock is attached to a base plate (not 20 shown) that is fixed to the load surface 12 by way of, but not limited to bolts, clamps or welds. The twistlock 10 may be slidably attached to the mounting plate by way of engagement surfaces 82, 84, 86 that are configured to cooperate with respective docking means of the base plate. The twistlock 10 may be secured by way of locking pins (not shown) that engages through apertures 88, 90 in rearwardly extending 25 projections 92, 94 of the housing 14. In this way the twistlock 10 can be removed from the load surface 12 when not in use. The reader should however appreciate the present invention could be used with other types of twistlocks, such as those fixed to a plate having ISO holes. 30 It is envisaged that there will be a close fit between the body portion and base plate. Thus there is not a great deal of play, which might otherwise lead to a greater inertia build-up to impact with greater force to damage the twistlock arrangement. The engagement surfaces 82, 84, 86 thus act to inhibit lifting of the twistlock and this fully inhibits lifting under the normal forces that can be expected during transport. The ο (Ν > Ο σ^ σ^ (Τ) ο Ό (Ν Ο (Ν 10 15 housing 14 may further include an aperture 96 for positioning of a sensor or the like therethrough.

As illustrated in figure 10a, to attach the shaft 18 to the housing 14 the retaining protrusions 20, 22 are aligned with recesses 38, 40. The shaft can then be inserted through the passageway 38 whereby the retaining protrusions 20, 22 pass through recesses 38, 40. Figure 10a illustrates the relative position of the cone 16a when the shaft is initially inserted through the passageway 38. Once the retaining protrusions 20, 22 are below the overhanging rim portions 32, 34, the shaft and cone are rotated, in the direction of arrow 100 by an angle of approximately 112° as indicated by broken lines 102, 104.

The retaining protrusions 20, 22 engage with an underside of the rim portions 32, 34 and in a second position, as illustrated in figure 10b, slit 54 engages an end of the 15 biasing spring 24 as previously illustrated in figure 9. Figure 10b further illustrates the relative position of the cone 16b when the biasing spring 24 is at rest wherein the cone in an engaging position relative to the casting of the shipping container.

Figure 10c illustrates the working angle of the twistlock, being approximately 45°, by 20 broken lines 104, 106. The shaft and cone are biased towards 104 and movable in the direction of arrow 108 between angles 104 and 106 relative to the body portion. The relative position of the cone is indicated by 16b and 16c in figure 10c. When in position 16c the cone can be inserted through the corner casing 110 of the shipping container. 25

Various features of the invention have been particularly shown and described in connection with the exemplified embodiments of the invention, however, it must be understood that these particular arrangements merely illustrate and that the invention is not limited thereto. Accordingly the invention can include various modifications, 30 which fall within the spirit and scope of the invention. It should be further understood that for the purpose of the specification the word “comprise” or “comprising” means “including but not limited to”.

Claims

CLAIMS:

1. A twistlock comprising a housing and a shaft supported for rotation by the housing, a cone extending upwardly of the housing for engagement with a corner casting of a shipping container, the cone integrally formed with the shaft, the shaft insertable into a top of the housing and retained therein by pairing an upwardly facing retention surface of the shaft and a downwardly facing retention surface of the housing, wherein the upwardly facing retention surface is on a radial protrusion of the shaft and the downwardly facing retention surface is on an overhang in a cavity in the housing, an insertion recess extends between the cavity and the top of the housing, the recess accommodating the protrusion, to allow for insertion of the shaft and protrusion, wherein the protrusion does not align with the insertion recess when the shaft is within a working rotation range, said working rotation range being at or between an engaging position and a disengaging position, and the twistlock further comprising a biasing means to bias the shaft and cone in one direction only being into the engaging position, the biasing means being fixed to the housing after the shaft is fitted and rotated into the working rotation range to thereby maintain the shaft in the working rotation range.
2. The twistlock of claim 1 wherein the protrusion has a flat upwardly facing retention surface that bears against the downwardly facing retention surface, thereby acting as a bearing when the shaft and housing are rotated relative to one another
3. The twistlock of either one of claims 1 or 2 there are two radially opposed protrusions
4. The twistlock of claim 3 wherein two radially opposed recesses are aligned with the two radially opposed protrusion.
5. The twistlock of either one of claims 3 or 4 wherein the protrusions are positioned above the biasing means so that only the shaft need be accommodated by the biasing means.
6. The twistlock of claim 5 wherein the housing include a passageway for receiving the shaft therethrough, the passageway extending between an upper surface of the housing and a chamber that holds the biasing means.
7. The twistlock of claim 6 wherein upper surfaces of the retaining protrusions form a shoulder that is configured to engage against the downwardly facing retention surface of the housing and the downwardly facing retention surfaces comprising overhanging rim portions that extend around a part of the edge of the passageway on opposing sides.
8. The twistlock of either claim 6 or 7 wherein the passageway is generally elongate and includes one or more recesses on opposing sides for receiving the retaining protrusions therethrough, the recesses being intermediate of the overhanging rim portions so that when the upper surfaces of the retaining protrusions are below the overhanging rim portions the shaft may be rotated such that the retaining protrusions engage with said rim portions.
9. The twistlock of claim 8 wherein the biasing means biases the protrusions from aligning with the recesses so that once the biasing means is connected to the shaft the retaining protrusions are inhibited from aligning with the recesses.
10. The twistlock of claim 9 further comprising a removable stop limit means to interact between the shaft and the housing to limit rotation.
11. The twistlock of any one of claims 1 to 10 wherein an upper part of the shaft is journalled for rotation about an upper bearing formed in the upper part of the housing, and the cavity is formed in the housing adjacent the upper bearing, so that the downwardly facing retention surface is formed adjacent the upper bearing, the upper bearing and the downwardly facing retention surface being interrupted by the one or more insertion recesses.
12. The twistlock of claim 11 wherein the one or more upwardly facing retaining surfaces are co-planar for rotation on the downwardly facing bearing surface.
13. The twistlock of any one of claims 1 to 12 wherein a lower bearing is provided at a lower end of the shaft, the lower end of the shaft is journalled for rotation in a bearing at a lowermost part of the housing.
14. The twistlock of claim 13 wherein the biasing means is positioned between the upper bearing arrangement and the lower bearing so that shaft bearings are located top and bottom of the biasing means.
15. The twistlock of any one of claims 1 to 14 wherein the biasing means is flat.
16. The twistlock of claim 15 wherein the biasing chamber comprises a flat chamber open out of the housing on one side, for insertion of the flat biasing means, in a direction transverse to the insertion of the shaft.