GB2209184A - Semi-automatic twistlock - Google Patents

Abstract

A semi-automatic twistlock device for lifting or securing containers and cargo platforms via corner fittings. It comprises the twistlock body 1 and collar 3 that locates in corner fitting aperture, the twistlock 2 and twistlock mechanism 4. To insert the device into corner fitting aperture the handle 15 is rotated against the force exerted by the helical torsion spring 20 to a stopped position whereupon the retaining head 11 is 'aligned' with the collar 3. When released, after insertion, the retaining head 11 rotates to the stopped 'crossed' position under the action of the restoring torque produced by the helical spring. The twistlock remains in the 'crossed' position and can only be withdrawn by rotating the handle against the spring back to the 'aligned' position. <IMAGE>

Description

Semi-automatic container lifting and lashing devic'Th - SPECIFICATION The present invention related to a hand operated container lifting/lashing device.

Devices are known to exist for lifting and lashing containers via corner fittings that prevent them from becoming free when the attached slings are slack. Such devices incorporate the standard twist lock principle used extensively during container transportation and lifting. Conventional hand operated twistlocks connected by some flexible sling to a lifting or anchor point subsequently referred to as the device comprises a solid body that couples the corner fitting to the sling via a shackle or similar connector. The device, therefore, contains a lug for the shackle and a collar that locates in the corner box aperture, and a twistlock mechanism. The twistlock mechanism comprises a retaining head, that projects into the corner fitting, mounted on a shaft that rotates relative to the main body of the device.This allows the device to be inserted and withdrawn from the corner fitting when the retaining head is aligned with the aperture collar and coupled to the corner fitting after rotating the twistlock through 900. In this position the retaining head is contained within the corner fitting cavity and the device cannot be extracted from it.

There are to major problems with devices in existance such as the one described in Patent Application No GB2l674SGA.

Firstly - rotation to the operating position after insertion is manual and failure to rotate the twist lock to the operating position is a possibility.

Secondly - the constraining torque exerted on the handle to maintain the twist lock in the operating position is minimal and only a slight force is necessary to knock the handle to the release position whereupon it would fall free from the vertical face of the corner fitting when side lifting.

The aim of the present invention is to present an improved device for the safe lifting and lashing of containers via the corner fittings that overcome the aforsaid disadvantages.

According to the present invention there is an integral shoe body containing shackle and twistlock lugs, an aperature collar, a twistlock and twist lock mechanism.

The shoe body, in the form of a single forged unit, contains both the shackle lug or bush and twistlock lug the axes of which are at 900 to one another. The aperture collar that locates in the corner fitting aperture is mounted on a boss integral with the shoe body and concentric with the twistlock lug. The aperture collar whilst not being an integral part of the shoe body is full constrained against angular displacement and can be set at any angular position depending on its intended application.

The twist lock comprises retaining head formed on the end of a shaft. The retaining head that projects into the corner box cavity is in series with the aperture collar when contained in s the body, both the head and collar having the same external profile as corner fitting apperture used. The twistlock is retained in the shoe body by a thrust ring welded to the shaft where it emerges from the twist lock lug of the body. The thrust ring reacts the force induced in the retaining head when lifting.

The twistlock-mechanism comprises a handle attached to the end of the twistlock shaft, a helical torsion spring positioned on the shaft and a spring housing cylinder concentric with the shaft and rigidly attached to the shoe body. This mechanism permits the two operating positions of the retaining head 900 apart.

One of these positions is the 'aligned' position where retaining head and aperture collar are in line, necessary for inserting and withdrawing the device from the corner fitting. The other position is the 'crossed' position where retaining head is at 0 90 to the aperture collar for retaining the device in the corner fitting and lifting. This is the position normally assumed by the twistlock under the action of the helical torsion spring.

The 900 movement is provided by the handle fitted with a pin that locates in a circumferential groove formed in the end of the spring housing cylinder. The torsion spring is fitted over the shaft and one end is anchored to an internal ring in the cylinder whilst the other end is contained in the handle. IniTial pre-torsion is applied before securing the handle to the shaft in order to hold the twistlock in the 'crossed' position. The 'aligned' position, therefore, can only be attained by manually actuating the handle and turning it against the torque exerted by the spring.

The handle rotation direction can only be one way. In the arrangement described it is anticlockwise since this coincides with an unscrewing action. Clockwise rotation is the alternative and only requires a helical torsion spring wound in the opposite hand.

The invention will be described further with the aid of accompanying diagrams listed below.

Fig. 1 is a perspective view of first embodiment of the invention showing its main components.

Fig. 2 is a perspective view of the device showing the twistlock mechanism.

Fig. 3 shows the device in the insert and withdraw position relative to corner fitting in the 'aligned' position.

Fig. 4 shows the device contained in a corner fitting in the 'crossed position Fig. 5 is a perspective view showing the aperture collar arrangement when the device is used in the horizontal position for lashing purposes.

With reference to fig. 1 the device comprises the shoe body 1, the twistlock 2, the aperture collar 3 and twistlock mechanism 4.

The shoe body contains the shackle bush 5, the twistlock lug 6, the aperture collar boss 7 and recess S. The aperture collar 3 contains a stop segment 9 that locates in recess 8 and prevents collar 3 from rotating. The collar 3 is held in position on boss 7 by peening the protruding lip of the boss at the positions 10.

The twistlock 2 contains the retaining head 11 and shaft 12.

With reference to fig. 2 the twistlock is contained in the twistlock lug 6 of the shoe body by welding the thrust ring 13 to the twistlock shaft 12. The spring housing cylinder 14 is positioned concentric with the twist lock shaft 12 and welded to the shoe body 1. The twistlock handle 15 is fixed to the twistlock shaft 12 by grub screws 16 in threaded holes at the handle/shaft interface 17.

The 900 rotation of the handle is produced by the pin 18 secured in the handle 15 rotating within the circumferential groove 19 machined in the end of the cylinder 14.

The helical torsion spring 20 has one end fixed in a hole drilled in the internal ring 21 of cylinder 14 and the other end secured in hole 22 in the handle. The angle between the holes that secure the spring enable the requisite amount of pre-torsion to be applied before fixing the handle to the shaft via grub screws. Under the action of the restoring torque exerted by the spring the retaining head 11 is maintained in the 'crossed' position relative to the collar 3.

In order to attain the 'aligned' position of the retaining head with the collar the handle is rotated in the unscrewing position, the device can then be inserted or extracted from the corner fitting as shown in figure 3.

en released the retaining head is restored to the 'crossed' position as shown in fig. 4 where it remains.

The first embodiment described has the major axis of the aperture collar in line with the shoe body axis 23 in fig. 1.

In this position the device can only be used to lift in vertical direction and the shoes are not handed. The collar can be positioned at any angle corresponding to the angular position of the recess 8 in the shoe body and fig. 5 shows the position 7 where major axis of collar is at 90 to the shoe body axis. The operating position of this device is horizontal and used to lash containers or cargo platforms again the device is not handed.

When a specific lifting angle is known as when end lifting from a single point and that angle remains constant for all freight units being lifted then the recess in the shoe body can be formed at the appropriate angular position to give right and left handed lifting devices incorporating the principles described for the first embodiment.

Claims (1)

1. CLAiMS

   A hand operated semi-automatic twist lock that engages in the corner fittings of containers and flats for their lifting or securing that comprises two main parts: the twistlock body and twistlock mechanism, the mechanism housed in the body is rotated by hand to a stopped position against the restoring force of a torsion spring whereupon the twist lock can be inserted into the corner fitting, when released the retaining head, now in the corner box cavity, rotates back to the initial stopped position under the action of the torsion spring alone and remains coupled until the mechanism handle is rotated back against the spring force and can then be extracted from the corner fitting