EP0018075B1

EP0018075B1 - Weight testing apparatus

Info

Publication number: EP0018075B1
Application number: EP19800300725
Authority: EP
Inventors: Graham Abraham Arthur
Original assignee: WATER WEIGHTS (INTERNATIONAL) Ltd
Current assignee: WATER WEIGHTS LIMITED
Priority date: 1979-03-07
Filing date: 1980-03-07
Publication date: 1985-10-30
Also published as: GB2047414B; EP0018075A1; GB2047414A; DE3071206D1

Description

The present invention relates to weight testing apparatus and particularly to apparatus for testing the lifting strength of hoists, winches, cranes and similar lifting devices.
Hitherto, weight testing equipment has comprised heavy and bulky weights of metal or concrete having means for attachment to a carrying structure which incorporates a dynamometer or other load measuring meter which indicates the total load borne by the hoist or crane and the inertial stress due to acceleration of the rate of lifting. Such testing equipment has frequently to be transported to a site or work centre for use. This can involve the transportation of weights which may be of the order or 40 tonnes or more and the storage of these weights when they are not in use. Both the transportation and storage of weights of this order creates many problems and costs.
In order to minimise these problems it has been proposed in French Patent Specification No. 2 296 171 to provide one or more rigid hollow containers which can be suspended from the crane or boom to be tested and then filled with water or any other liquid to increase the weight of the container. It is also proposed in this specification to rigidly suspend a second container below the first in order to further increase the test weight of the device. While this known arrangement is an improvement on the use of solid concrete or steel blocks it has the disadvantages that, the enclosures being rigid, they are difficult to handle and take up space, even when empty. Furthermore, the connections between an array of suspended containers being rigid creates problems of loading and balance in use.
It has also been proposed, in French Specification No. 1 484 956 to use a flexible liquid container for the purpose of testing floors and other horizontal surfaces. In this specification however no account is taken of the problems inherent in suspending a heavy flexible container from a support.
U.K. Specification No. 783, 407 is concerned with collapsible containers and envisages the use of an outlet tube housed within the container and Swiss Specification No. 362 980 is concerned with a flexible bag for holding granular material. U.K. Patent No. 1 501 763 discloses a disposable container for the transportation and storage of flowable materials comprising a bag of flexible sheet material and straps attached at spaced locations on the exterior of the sheet material for supporting the bag. None of these specifications however is addressed to the problem of suspending a flexible weight testing bag from a support.
It is an object of the present invention to provide a weight testing apparatus which obviates or substantially reduces the problems inherent in transporting and storing bulky and heavy weights or rigid containers and further to provide weight testing apparatus which is easily transportable by air, for instance by helicopter, to an oil rig or other off shore structure which is moored at sea.
In accordance with one aspect of the present invention we therefore provide weight testing apparatus comprising a liquid impervious bag, a liquid outlet at the bottom end of the bag, operable to retain liquid in the bag, an inlet at the top end of the bag and means for suspending the bag from a support by elongate load bearing elements which are flexible and generally uniformly spaced around the bag so that the bag is uniformly supported against burst forces exerted on it by the weight of a liquid contained therein characterised in that the liquid outlet comprises an outlet tube which extends from the bottom end of the bag wholly externally of the bag and is of a length such that its end can be positioned and retained above the top end of the bag.
The bag is preferably pear-shaped and open topped. If the bag is open topped it can be filled easily through the open top and emptied through the flexible outlet tube. The flexible outlet tube is effectively closed by attaching it to the side of the bag with the top of the tube located adjacent the top of the bag during the filling operation and when the bag .is in use.
The bag can be adapted to support a second bag suspended below the first by providing a load supporting cable which extends through the bag from top to bottom, whereby a load can be supported on the cable beneath the bag without adding any further load to the bag or the elements thereof. Preferably the cable extends through a sleeve which is joined in a fluid sealed relationship to the bottom of the bag and which extends upwardly to a point adjacent the upper end of the bag.
In use, the apparatus can be transported to the site in an empty flat, folded or rolled up condition, suspended from the winch or crane to be tested and then filled with water to a predetermined level necessary for the application of the specified testing load. When the test has been completed the apparatus can be emptied by lowering the flexible outlet tube, the empty bag removed from the winch, packed and transported to the next site of use.
In many circumstances, where very heavy loads are required, it is envisaged that a plurality of the flexible fluid impervious bag of the present invention may be suspended from a support frame comprising a node and a plurality of arms extending outwardly from the node, the arms being equiangularly spaced around the node and each arm having means adjacent its outer end for attaching on bag thereto. The outer ends of the adjacent arms of the support frame may be joined by links adapted to spread a transverse load applied to any one arm equally throughout the structure and the support frame may be suspended from a single load carrying boss by a plurality of cables each of which extends from the boss and through a sleeve at or adjacent an outer end of an arm.
In order to fill the plurality of bag suspended from the support frame, an inlet manifold may be provided on the support frame for filing the bags.
A preferred form of the present invention will now be described with reference to the accompanying drawings, in which:-

Figure 1 is an elevation of a weight testing bag in accordance with the present invention;
Figure 2 is a plan view of the bag shown in Figure 1;
Figure 3 is a vertical section through the bag of Figures 1 and 2;
Figure 4 is a perspective view showing two of the bags of Figures 1 to 3 in use suspended from a support;
Figure 5 is a perspective view showing a plurality of the bags of Figures 1 to 3 suspended from a support frame;
Figure 6 is a diagrammatic plan view of the support frame of Figure 5; and
Figure 7 is a diagrammatic elevation showing the support frame of Figure 5 carrying two tiers of bags.

In Figures 1 to 3 a weight testing bag of the present invention is indicated generally at 10. The weight testing bag 10 comprises a flexible envelope 11 which is generally pear shaped and which is made from a fluid impervious material such as reinforced polyvinyl chloride or neoprene. The envelope 11 is open topped at 12 and has an outlet 13 at the bottom leading to a flexible outlet tube 14. The flexible outlet tube 14 is of a length such that it can be raised and attached to the side of the envelope by a strap 15 so that its upper end 16 is located above the upper end of the envelope 11.
The envelope 11 is supported by a plurality of strengthening straps 17 made of webbing or any other similar material. The straps 17 extend from the bottom of the envelope upwardly through sleeves 18 which are attached to the outer surface of the envelope. Each strap terminates in an eye 19 which is attached to a shackle 20 which is itself mounted on a support boss 21 having an upwardly extending hook 22 which enables the bag to be easily suspended from a piece of apparatus to be weight tested. The hook 22 may alternatively be replaced by a conventional shackle arrangement if this is preferred.
A load carrying cable 23 extends through the envelope 11 from top to bottom. The upper end of the cable 23 terminates in a hook 24 which can be easily attached to a hook or eye 25 which is integral with the boss 21 and the lower end of the cable 23 terminates in an eye 26 which enables a second bag to be suspended below the first bag. The cable 23 extends through a sleeve 27, the bottom end of which is joined in a fluid sealed relationship to the bottom of the envelope 11 so as to form an outlet 28 at the bottom of the envelope for the cable 23. The upper end of the sleeve 27 extends approximately to the upper end of the envelope 11 so that the cable is sealed from the contents of the bag at all times.
In use, the bag in its unfilled condition can be attached to a winch or other piece of apparatus to be weight tested by means of the hook 22. The outlet tube 14 is then attached in its upright position by means of the strap 15 and the bag can be filled with water or any other liquid through the open top of the envelope 11. The capacity of the bag 10 will be known and it can be filled to an extent sufficient to provide the required weight test. When the test has been completed, the bag can be quickly and easily emptied by releasing the outlet tube 14 and allowing it to fall away from the upper end of the bag. The bag is then emptied under gravity through the outlet tube 14. When the bag has been emptied it can then be removed from the apparatus being tested, folded and transported to its next site of use.
As can be seen from Figure 4, two or more of the bags 10 may be suspended from a single hook or eye 29 and a second tier of bags suspended below the first tier from the eyes 26. However, the number of bags which can be suspended from a single hook or eye is limited because of the bulk of the bags when they are filled with water and we therefore provide a frame for supporting and spacing a plurality of bags below the same load carrying point. This supporting and spacing frame is indicated generally at 30 in Figures 5 to 7. The frame 30 comprises a central node 31 carrying six similar arms 32 which extend radially outwardly from the node 31. The arms 32 are slotted into sockets provided in the node 31 and are equiangularly positioned around the node. The outer ends of the arms 32 are joined by links 34 which are adapted to spread a load applied to any one arm equally throughout the frame. The frame 30 is suspended from a single load carrying boss 35 by a plurality of load carrying cables 36 each one of which extends from the boss 35 to an outer end of an arm 32, where it passes through a sleeve 37. The end of each cable 36 carries an eye 38 from which a bag 10 can be suspended by its hook 22.
In use, an empty bag 10 is suspended on a cable 36 beneath each of the six arms 32 and the boss 35 is then suspended from the piece of apparatus to be weight tested by means of a U-shaped hook 39 which extends upwardly from the boss 35. When the frame and the bags suspended therefrom are in position, each of the bags is filled with water up to the required weight.
In order to minimise the strain on the frame 30 the bags should be filled uniformly. The frame 30 may therefore be provided with three inlet manifolds which are not shown but which may be mounted on the arms 32 and adapted to fill two diametrically opposite bags simultaneously. This ensures that a substantial weight imbalance cannot occur as the bags are filled.
If a greater weight is required than can be provided by a first tier of bags 10 suspended from the frame 30 then a second tier of bags 10a can be suspended below the first tier of bags as shown in Figure 7.
By varying the size of the bags employed and by controlling the rate of fill to each bag it is possible to fill a plurality of different sizes of bags simultaneously without overspill or waste. The manifolds on the support frame are also preferably designed to minimise turbulence in the filling of the bags.
In order to minimise the weight of the apparatus and to resist oxidation, the metal components may be made as far as possible from duralumin so as to provide a rust-resistant extremely lightweight construction in relation to the weight or mass provided when the bag or bags are filled to the required extent.

Claims

1. Weight testing apparatus comprising a liquid impervious bag (10, 10a),a liquid outlet (13) at the bottom end of the bag, (10, 1 Oa) operable to retain liquid in the bag (10, 10a), an inlet at the top end (12) of the bag (10, 10a) and means for suspending the bag from a support (21) by elongate load bearing elements (17) which are flexible and generally uniformly spaced around the bag (10, 10a) so that the bag (10, 10a) is uniformly supported against burst forces exerted on it by the weight of a liquid contained therein characterised in that the liquid outlet (13) comprises an outlet tube (14) which extends from the bottom end of the bag (10, 10a) wholly externally of the bag and is of a length such that its end (16) can be positioned and retained above the top end of the bag '(10, 10a).

2. Weight testing apparatus as claimed in claim 1 characterised in that the elements (17) are attached to a load carrying boss (21).

3. Weight testing apparatus as claimed in any preceding claim, characterised in that the bag (10, 10a) comprises a liquid impervious envelope (11) which is generally pear-shaped and open topped.

4. Weight testing apparatus as claimed in any preceding claim, characterised in that a load supporting cable (23) extends through the bag (10, 10a) from top to bottom, whereby a load can be supported on the cable (23) beneath the bag (10, 10a) without adding any further load to the bag (10, 10a) or to the load bearing elements (17).

5. Weight testing apparatus as claimed in claim 4, characterised in that the cable (23) extends through a sleeve (27) which is joined in a fluid sealed relationship to the bottom of the bag (10, 10a) and which extends upwardly to a point adjacent the upper end of the bag (10, 10a).

6. Weight testing apparatus comprising a plurality of bags (10, 10a) as claimed in any preceding claim suspended from below a supporting frame (30) comprising a node (31) and a plurality of arms (32) extending outwardly from the node (31, characterised in that the arms (32) are equiangularly spaced around the node (31) and a bag (10, 10a) is suspended from each arm (32) at or adjacent the outer end of the arm (32).

7. Weight testing apparatus as claimed in claim 6 characterised in that the support frame (30) comprises an even number of arms (32).

8. Weight testing apparatus as claimed in claim 6 or claim 7, characterised in that the outer ends of adjacent arms (32) are joined by links (34) adapted to spread a transverse load applied to any one arm (32) equally throughout the struc- tu re.

9. Weight testing apparatus as claimed in any of claims 6 to 8, characterised in that the support frame (30) is suspended from a single load carrying boss (35) by a plurality of cables (36) each of which extends from the boss (35) to an outer end of an arm (32).

10. Weight testing apparatus as claimed in claim 9, characterised in that each cable (36) extends below an arm (32) and is provided with means for suspending a bag (10, 10a) therefrom.

11. Weight testing apparatus as claimed in any of claims 6 to 10, characterised in that a fluid inlet manifold is provided on the support frame (30) for filling the bags (10, 10a) with fluid.

12. Weight testing apparatus as claimed in claim 11, characterised in that the fluid inlet manifold is adapted to fill diametrically oppositely positioned bags (10, 10a) simultaneously.