GB2138151A

GB2138151A - Load test apparatus

Info

Publication number: GB2138151A
Application number: GB08303021A
Authority: GB
Inventors: A G Abraham
Original assignee: WATER WEIGHTS Ltd
Current assignee: WATER WEIGHTS Ltd
Priority date: 1983-02-03
Filing date: 1983-02-03
Publication date: 1984-10-17
Also published as: AU1359883A; GB2138151B; GB8303021D0; AU552515B2

Abstract

A load test bag 10 for carrying fluid or the like material comprises an open top and a load carrying frame 16 incorporating suspension means for suspending the bag from a structure to be tested. The load carrying frame is located in the bag with the suspension means positioned at or adjacent the top end of the bag. <IMAGE>

Description

SPECIFICATION Load testing apparatus The present invention relates to apparatus for testing the strength of a structure such as a crane boom by suspending a predetermined weight from the structure.

In our U.K. Patent No. 2,047,414 we have described apparatus comprising a liquid impervious bag which is surrounded by a plurality of elongate load bearing elements which carry the bag and support it against burst forces exerted on it by the weight of liquid contained in the bag. The elongate load bearing elements extend upwardly beyond the open top of the bag to a boss or frame which has means for suspending the bag from a support.

In many situations, it is necessary to suspend several tiers of bags from the structure to be tested.

It is therefore desirable to reduce the vertical space occupied by each bag to a minimum so as to reduce the overall height of the apparatus which is suspended from the structure being tested. With hitherto known bags, and in particular with those exemplified in our earlier patent, the elongate load bearing elements which support the bag extend upwardly from the open top of the bag to the boss by a distance which may be as much as one third of the overall height of the bag. This represents wasted space and it is an object of the present invention to provide a load testing apparatus which eliminates or substantially reduces this wasted space.

According to one aspect of the present invention there is provided a load testing bag for carrying fluid or the like material comprising an open top and a load carrying frame incorporating suspension means for suspending the bag from a structure to be tested, characterised in that the load carrying frame is located in the bag with the suspension means positioned at or adjacent the top end of the bag.

Preferably, the frame comprises a vertical stem extending into the bag, a plurality of radial struts each connected at one end to the vertical stem, and a plurality of stays each connected at one end to the bottom of the vertical stem and at the other end to the outer end of a radial strut.

A preferred form of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a bag in accordance with the present invention; Figure 2 is a vertical section through the bag of Figure 1; Figure 3 is a perspective view of a detail of the bag shown in Figures 1 and 2, and Figure 4 is a view of a plurality of the bags of Figures 1 to 3 suspended from a crane structure.

In the drawings, a bag for testing the strength of the boom of a crane or similar structure is indicated generally at 10. The bag 10 is made from a tough woven plastics material and is water impermeable.

The bag is supported by a plurality of flexible elongate webbing straps 11 which are arranged equiangularly around the bag and which support it against burst forces created by the weight of water orfluid in the bag when the bag is full. The straps 11 are wrapped around and stitched to a load bearing ring 12 at the bottom end of the bag and extend over the full length ofthe bag through sleeves 13 to the top end 14 which is open.

The bag 10 is intended to be filled through the open top 14 and emptied through a flexible outlet tube 15 which is tied to the top end of the bag during the filling operation and allowed to fall away when the bag is emptied.

Positioned within the open end 14 of the bag is a load carrying frame which is indicated generally at 16. The frame 16 comprises a vertical central stem 17 in the form of a steel tube having a plate 18 welded to its upper end and formed with an eye 19 for receiving a shackle pin, not shown. The eye 19, which enables the bag to be suspended from a support or directly from the structure to be tested, is positioned immediately above the open end of the bag. Just below the open end of the bag a plurality of radial struts 20 extend outwardly from the stem 17.

The struts 20 are welded to the stem 17 and spaced equi-angularly around the stem. Each strut 20 is welded, at its outer end, to a link 21. Both the struts 20 and links 21 are formed from tubular steel and each link 21 has a pin 22 at its outer end which is formed with a yoke 23 and clevis pin 24. An end of a webbing strap 11 is wrapped around each pin 24 and stitched back onto itself to secure the strap to the frame 16. The bottom end of each link 21 is welded to the bottom end of the stem 17 and a strengthening plate 25 is welded into the bottom end of the stem to complete the frame 16. Spacing rods 26 extend between and are welded to adjacent radial struts 20 to space the struts apart and stiffen the whole structure of the frame.

In use, the frame 16 serves several purposes. It ensures that the mouth of the bag is held open making filling of the bag with water relatively easy. It also enables the supporting straps 11 to be terminated at the top end of the bag and the bag to be suspended from the eye 19 which is positioned closely adjacent the top end of the bag. This enables a plurality of bags to be suspended one below the other, as shown in Figure 4, with only a minimum of wasted vertical space between adjacent tiers of bags. Where is is necessary to employ a large number of bags to achieve the desired weight, this enables a greater number of tiers of bags to be suspended in a given vertical space.

It is envisaged that the radial struts may be length adjustable to accommodate different bag diameters or, alternatively, may be in the form of flexible straps. In order to increase the rigidity of the frame 16, it is alternatively envisaged that triangular metal plates can be welded between the stem, and the raidal struts and the stays to form a plurality of radially arranged stiffening fins around the central stem 17. It is only envisaged that this would be necessary or desirable in an exceptionally large bag carrying a weight of 50 tons or more when fully loaded.

In use, the bag is attached to a supporting hook 27, which may form a part of the structure to be tested or it may be suspended from another bag or from a framework 28 as shown in Figure 4, which is itself suspended from the structure to be tested. The bag or each bag is then filled with water in order to apply a load to the structure to be tested. When the testing is complete, the outlet tube 15 which is tied to the upper end of the bag 10 is released so that it falls away. Water then runs out of the outlet tube 14 so as to empty the bag which can then be readily removed from the structure, folded and transported away.

Claims

1. A load test bag for carrying fluid or the like material comprising an open top and a load carrying frame incorporating suspension means for suspending the bag from a structure to be tested, characterised in that the load carrying is located in the bag with the suspension means positioned at or adjacent the top end of the bag.

2. A bag as claimed in claim 1 characterised in that the frame comprises a vertical stem extending into the bag, a plurality of radial struts each connected at one end to the vertical stem and a plurality of stays, each connected at one end to the bottom of the vertical stem and at the other end to the outer end of a radial strut.

3. A bag as claimed in claim 2, characterised in that the bag is supported by a plurality of flexible straps, each extending from the bottom of the bag upwardly to the outer end of one of the radial struts whereby the weight of the bag is taken substantially by the frame and the straps.

4. A bag as claimed in claim 3, characterised in that the suspension means is located at the top end of the vertical stem.

5. A bag as claimed in any of claims 2 to 4, characterised in that each radial strut is adjustable for length to accommodate different sizes of bag.

6. A bag as claimed in any of claims 2 to 5 characterised in that each radial strut comprises a flexible strap.

7. A bag as claimed in any of claims 2 to 5 characterised in that each radial strut is in the form of a rigid bar or tube.

8. A bag as claimed in claim 6 characterised in that each radial strut is rigidly attached to the vertical stem.

9. A bag as claimed in claim 7, characterised in that each radial strut is hinged to the vertical stem.

10. A bag as claimed in any of claims 2 to 9, characterised in that each stay is hinged to the bottom end of the vertical stem.

11.A load testing bag substantially as described herein with reference to the accompanying drawings.