AU2022211897B2

AU2022211897B2 - Steel activator for container twist lock

Info

Publication number: AU2022211897B2
Application number: AU2022211897A
Authority: AU
Inventors: Ture Nyholm
Original assignee: Skrin Pty Ltd
Current assignee: Skrin Pty Ltd
Priority date: 2016-02-11
Filing date: 2022-08-05
Publication date: 2022-10-06
Anticipated expiration: 2037-02-10
Also published as: FR3047702B1; AU2017200922A1; FR3047702A1; NZ729024A; AU2022211897A1; GB2549367B; GB201702196D0; DE102017102665B4; DE102017102665A1; GB2549367A

Abstract

The present invention provides a biasing means for a container twist lock in which the biasing means is a torsional spring with spiral coils that has a first end that engages within the twist lock assembly and a second end that engages with the shaft of the 5 twist lock assembly. The torsional spring provides a more robust and secure engagement of the head of the twist lock assembly. The addition of an indicator arm operatively engaging with the spring provides a way of assessing the condition of the twist lock spring as either being in the lock or unlock position.

Description

STEEL ACTIVATOR FOR CONTAINER TWIST LOCK

The present application is a divisional application of Australian application no. 2017200922 and is incorporated in its entirety by reference. This application claims the benefit of priority of provisional patent application no. 2016900457, filed 11 February 2016, the contents of which are incorporated herein by reference in their entirety

FIELD OF THE INVENTION

The present invention relates to devices for securing containers, in particular cargo containers, providing automatic securing connection and release of a cargo container

DESCRIPTION OF THE PRIOR ART

The use of containers in the transportation of goods is commonplace due to the ease of cargo handling as well as labour savings when compared to non-containerised transportation. Modular containers can be shipped from one point to another relatively easy and efficiently using a number of different carrier systems, such as trucks, ships and rail cars.

The modular containers have hollow comer castings with apertures passing through them to receive a secure and bias such as a twist lock.

A twist lock includes a base upon which the container can rest along with a head section that is rotated with respect to the base portion such that in a first rotational position (open position) the head can pass through the aperture of the corner casting of the container. In a second rotational position (locked position) the head is offset with respect to the aperture and as such it is not able to move through the aperture and therefore secures the container against the housing or base. Typically, a twist lock employs a biasing means, such as a spring, within the base portion, the biasing means in operation when torque is applied by engagement of the hollow corner casting with the head section of the twist lock. The biasing means provides a resistive force to the rotation of the head of the twist lock and it is not until this resistive force has been achieved will the head move to the open position to allow the container to be released.

Other alternative biasing means for twist locks include rubber blocks that fit within the base of the twist lock. The advantage of using a rubber biasing means in a twist lock is well known, in particular its resiliency and ease of maintenance. Such rubber biasing means are disclosed in AU 687217 as well as US4626155.

With reference to US4626155, and figure 1, the twist lock 5 has a head section 7 connected to a shaft 9. The biasing means is a rubber spring assembly 10 that is keyed to operate in unison with the shaft 9, all of which is housed within the housing portion 2 and 3. Key elements 11 protrude from the shaft 9 and slot within the openings 12 of the rubber spring assembly 10. The head section 7 can only be rotated from its first position to a second position by deformation of the rubber spring assembly 10.

However, it has been observed over time that traditional spring and rubber biasing means twist locks are susceptible to weather. For example, when there is a marked decrease in ambient temperature, such as when a freight train travels from one part of the country to another, then the rubber biasing means can become hard requiring a marked increase entry and/or exit force so as to effect a rotational of the head section of the twist lock.

Conversely, when there is a marked increase in ambient temperatures then the rubber biasing means can become softer thus decreasing the entry and/or exit force required to rotate the head section, plus potentially causing a safety issue whereby the secured container may become unsecured.

Such changes in ambient temperatures experienced by freight trains are more common than perhaps what is expected, particularly for freight trains travelling through cold climates. It is a problem therefore in designing a twist lock biasing means that is resilient to changes in ambient temperatures and provides sufficient force to ensure that the attached container is held in a secure manner regardless of environmental conditions and ensures a long working life of the twist lock without excessive maintenance.

OBJECT OF THE INVENTION

It is an object of the present invention to overcome, or at least substantially ameliorate, the disadvantages and shortcomings of the prior art.

Other objects and advantages of the present invention will become apparent from the following description, taking in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.

SUMMARY OF THE INVENTION

According to the present invention, although this should not be seen as limiting the invention in any way, there is provided a biasing means for a twist lock assembly, the biasing means being a flat torsional spring having spiral coils, a central first engaging end to receive a shaft, and a second end having a securing notch to interface with an interior of a twist lock assembly.

In preference, the flat torsional spring is an annular torsional spring.

In preference, the flat torsional spring spiral coils are eccentric.

In preference, the twist lock includes a rotatable head section, the head section having a shaft with a biasing means engaging end.

In preference the biasing means engaging end is substantially circular.

In preference, the biasing means engaging end has at least one protrusion thereon.

In preference, the at least one protrusion extends from an outer periphery of the biasing means engaging end.

In preference, the biasing means has a central first engaging end shaped to mate substantially with the biasing means engaging end of the shaft.

In preference, the flat torsional spring is elliptical in shape.

In preference, the flat torsional spring has a stem section extending from a central inner periphery located at the central first engaging end.

In preference, the stem section is offset from a central axis of the central inner periphery at the central first engaging end.

In preference, the stem section has a greater width than coils of the flat torsional spring.

In preference, the flat torsional spring has a relaxed state and an active state.

In preference, the flat torsional spring includes an indicator arm projecting from an outer surface of the flat torsional spring, the indicator arm configured to indicate if the flat torsional spring is a relaxed state and an active state.

In preference, the indicator arm projecting from the outer surface of the flat torsional spring projects substantially tangentially

In preference, the flat torsional spring and the indicator arm are operatively connected.

In preference, the flat torsional spring and the indicator arm are operatively connected by way of interlocking engagement means.

In preference, the interlocking engagement means is a dovetail joint between the flat torsional spring and the indicator arm.

In preference, the interlocking engagement means is a notch on the outer periphery of the flat torsional spring.

In preference, the indicator arm includes a projecting lug.

In preference, the flat torsional spring includes a lug projecting from an outer surface of the flat torsional spring.

In preference, the lug projecting from the outer surface of the flat torsional spring fits within a notch on the indicator arm.

BRIEF DESCRIPTION OF THE DRAWINGS

By way of example, an embodiment of the invention is described more fully hereinafter with reference to the accompanying drawings, in which:

Figure 1 is an exploded perspective view of an example of a twist lock assembly of the prior art showing a rubber biasing means;

Figure 2 is a perspective view of the present invention;

Figure 3 is a plan view of the present invention;

Figure 4 is a side view of figure 3;

Figure 5 is a perspective view of the present invention with an indicator arm attached;

Figure 6 is a top view of the invention as shown in figure 5;

Figure 7 is a side view of the invention as shown in figure 6;

Figure 8 is a perspective view of a further form of the invention;

Figure 9 is a top view of the invention as shown in figure 8.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the twist lock assembly of the prior art figure 1 and the rubber biasing means 10, also referred to as a spring or activator, the twist lock operation is dependent upon the ability of the rubber biasing means 10 to deform in a consistent and reliable manner so as to ensure that the head 7 of the twist lock 5 engages with the container when required. The twist lock assembly has a base 2, which supports it and a head section 3 to form the housing portion of the twist lock assembly, shaft section 9 and a biasing means/activator 10. The shaft 9 resides in the housing formed by the base 2 and head section 3 and is partially supported by the base, the shaft 9 is rotatable about an axis of rotation that extends the length of the shaft, rotation of the shaft 9 results in the head 7 rotating between a locked position, in order to engage with a bottom of a container, and unlocked or loading position. As the shaft 9 rotates from an unlock position to a lock position the rubber biasing means is deformed so as to bias the head 7 towards the locked position.

The biasing means or activator of the present invention is a spiral, torsional spring 15 that is formed from a suitably resilient metallic material as shown in figure 2.

The torsional spring 15 is annular or circular in shape and has an outer periphery 17 and an inner periphery 20. The inner periphery 20 is at a first spring end 19, which is a shaft engaging end, and defines a central shaft interface 21 for receiving and engaging a shaft that is connected to the head of a twist lock. To ensure a positive location of the shaft within the central shaft interface, there is at least one protruding lug located on the outer surface of the shaft, the protruding lug positively coupling or nesting within the inner periphery 20, which is shaped to have a substantially annular or circular section 22 and a flat section 24. At either end of the flat section 24 is a notch or indentation 26 shaped to receive a mating ridge on the shaft to increase the cooperative fit.

A stem section 27 is offset from the central axis 30 such that the width 31 of the stem 27 is substantially greater than, for example, the width of the coils 33 of the spring. By having an increase in the amount of material in the stem 27 it has been seen that there is a dramatic increase in the resiliency of the spring towards potential catastrophic failure of the stem compared to, for example, where a stem extends directly out in line with the axis 36.

A notch 38 is positioned on the second spring end 40, the notch 38 cooperatively engaging with a means for fixing the spring end within a spring housing or cavity so as to prevent any rotational movement of the second spring end 40. For example, the notch 38 can engage with a suitably shaped lug or projection that projects from an inner surface of the spring housing (not shown).

The spiral coils 33 are substantially circular in shape however in a further embodiment it has been shown that the spiral coils 33 provide increased performance in terms of resiliency to temperature changes and also providing more consistent forces for activation when in an elliptical orientation as shown in the figures 2 and 3.

In normal use, the torsional spring 15, when in a relaxed state, holds the shaft of the head of the twist lock in a first position, a locked position, in order to ensure that the container is actively restrained by the twist lock assembly.

When the twist lock is opened, a shaft passing through the center opening 21 of the torsional spring 15 is rotated and as the torsional spring 15 is in engagement with the inside of the twist lock assembly at its second end 40 the rotation introduces torque to the torsional spring 15, as the notch 38 prevents rotation of the torsional spring 15 within the spring housing, causing the torsional spring 15 to deform.

The geometry and shape of the coils 33 provide modulated and consistent resistance thus ensuring that once the head of the twist lock assembly has passed through a respective opening of the container corner casting then the torsional spring 15 returns the head of the twist lock back to the locked position thus securing the container in place.

When the container is lifted upwards to be removed a force is applied to the underside of the head of the twist lock in the locked position thus once again causing the head of the twist lock and the attached shaft to rotate from the locked position causing the torsional spring 15 to deform so that it is in an active state. When the container is clear of the head of the twist lock assembly then the torque from the torsional spring 15 to the engaged shaft forces the head of the twist lock back to its locked position.

The torsional spring 15 of the present invention has been shown to be more effective and consistent in operation and resiliency when compared with a standard spring element, such as the rubber spring assemblies of the prior art, as well as comparison with torsional springs that are of a consistent width/diameter.

Torsional springs of the prior art have been shown to be susceptible to changes in temperature as well as having significant stress points as a result of the internal elastic stress created by the defamation/strain. Such stress is exaggerated by the heavyweight of the containers as well as the repetitive action of the locking/unlocking of the containers from the twist lock over a long period of time.

Additionally, the torsional spring 15 can include an indicator arm either integrally formed or operatively coupled to it.

As shown in figure 5, the torsional spring 100 is similar to that as shown in the figures 2-4, in that it has an outer periphery 117 and an inner periphery 120. The inner periphery 120 is at a first spring end 119 that defines a central shaft interface 121 for receiving and engaging a shaft that is connected to the head of a twist lock.

To ensure a positive location of the shaft within the central shaft interface 121, there is at least one protruding lug located on the outer surface of the shaft, the protruding lug positively coupling or nesting within the inner periphery 120, which is shaped to have a substantially annular or circular section 122 and a flat section 124. At either end of the flat section 124 is a notch or indentation 126 shaped to receive a mating ridge on the shaft to increase the cooperative fit. A notch 138 is located at the second spring end 140.

Located on the outer periphery 117 of the spring 100 is a lug 130, projecting outwards away from the torsional spring 100. The lug 130 is shaped to nest or operatively engage with a notch 160 at a first send 152 of an indicator arm 150. The operative coupling of the lug 130 with the notch 160 forms an interlocking engagement means which is a dovetail joint.

The lug 130 is located on the spring 100 at an angle to the longitudinal axis 151 of the indicator arm 150, the first end 152 thus being slightly curved to provide substantially flush engagement with the outer periphery 117 of the torsional spring 100. The indicator arm 150 thus projects substantially tangentially from the torsional spring 100 and is of a sufficient length that results in the second end 154 being visible from outside of the housing unit for the torsional spring 100.

As shown in figure 6, the spring 100 is in a relaxed state, however, when forced into an active state, by rotation either clockwise or counter clockwise though arc 170, the lug 130 will also be forced to move and this movement is translated to the indicator arm 150 though arc 175 that is visible from the outside of the housing within which it is contained, preferably via an opening in the housing.

Another form of dovetail joint between the spring and the indicator arm is shown in figure 8 and 9 where the spring 180, has a notch 182 on the outer periphery 187, shaped to receive the projecting lug 190 on the second end 192 of the indicator arm 195.

The indicator arm may also be cast or formed integrally with the spring resulting in a single piece structure.

As can now be readily appreciated by those skilled in the field, the present invention of the torsional spring for a twist lock provides a novel biasing means that greatly improves the functionality of the twist lock. Being made from a suitable meal material rather provides strength and resiliency into the twist-lock mechanism used to secure containers, which is important when the twist-lock mechanism is exposed to harsh weather conditions, in particular freezing temperatures, that can quickly erode the functioning of traditional rubber based biasing means.

Moreover, the present invention provides a mechanism for quickly and safely determining the status of the torsional spring by way of the indicator arm that is in operative connection with the torsional spring. Once a container has been locked in place by the action of the twist-lock, an operator can quickly visually check the status of each twist lock by reference to the position of the indicator arm, which indicates if the spring is either in the relaxed state or the active state.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures can be made within the scope of the invention, which is not to be limited to the details described herein but it is to be accorded the full scope of the appended claims so as to embrace any and all equivalent devices and apparatus.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A biasing means for a twist lock assembly, the biasing means having a flat torsional spring having spiral coils, a central first engaging end with a centre opening to receive a shaft with a stem section extending from a central inner periphery located at the central first engaging end, and a second end having a securing notch to interface with an interior of the twist lock, further characterised in the flat torsional spring spiral coils are eccentric and the stem section is offset from a central axis of the central inner periphery at the central first engaging end.

2. The biasing means of claim 1, further characterised in that the flat torsional spring is an annular torsional spring.

3. The biasing means of any one of claims 1 or 2, further characterised in that the twist lock includes a rotatable head section, the head section having a shaft with a biasing means engaging end.

4. The biasing means of claim 3, further characterised in that the biasing means engaging end is substantially circular.

5. The biasing means of claim 4, further characterised in that biasing means engaging end has at least one protrusion thereon.

6. The biasing means of claim 5, further characterised in that the at least one protrusion extends from an outer periphery of the biasing means engaging end.

7. The biasing means of claim 1, further characterised in that the biasing means has a central first engaging end shaped to mate substantially with the biasing means receiving end of the shaft.

8. The biasing means of any one of claims 1-7, further characterised in that the flat torsional spring is elliptical in shape.

9. The biasing means of claim 8, further characterised in that the stem section has a greater width than coils of the flat torsional spring.

10. The biasing means of anyone of claims 1-9, wherein the flat torsional spring has a relaxed state and an active state and is operative between the relaxed state and the active state.

11. The biasing means of claim 10, wherein the flat torsional spring includes an indicator arm projecting from an outer surface of the spring, the indicator arm configured to indicate if the flat torsional spring is a relaxed state and an active state.

12. The biasing means of claim 11, wherein the flat torsional spring and the indicator arm are operatively connected.

13. The biasing means of claim 12, wherein the flat torsional spring and the indicator arm are operatively connected by way of an interlocking engagement means.

14. The biasing means of claim 10, wherein the flat torsional spring includes a lug projecting from an outer surface of the spring.

15. The biasing means of claim 13, wherein the lug projecting from the outer surface of the flat torsional spring fits within a notch on the indicator arm.