WO1984002329A1

WO1984002329A1 - Grab device for the transportation of objects, such as oblong tubes

Info

Publication number: WO1984002329A1
Application number: PCT/NL1983/000049
Authority: WO
Inventors: Willem Johannes Kors
Original assignee: Willem Johannes Kors
Priority date: 1982-12-10
Filing date: 1983-12-10
Publication date: 1984-06-21
Also published as: NL8204782A

Abstract

Grab device for the transportation of objects, such as oblong tubes (21). The grab comprises a tubular carrier (1; 31) which is provided at the outer ends with hooks (9) to be hooked on to the object to be transported. These hooks are outwardly moved by a preferably hydraulic device (6, 7; 33), said hydraulic device being connected via dampening means, such as a throttle place or a regulating valve, with a supply vessel for hydraulic liquid. When the grab is being hoisted, the own weight of the grab pushes the hooks inwardly until the tube is hooked, up, after which the tube can be transported. After putting down of the tube, the grab is being rested on the tube without hoisting force, whereby the hooks (9) are disconnected from the tube (21).

Description

Grab device for the transportation of objects, such as oblong tubes.

The invention relates to a device such as described in the preamble of claim 1.

A similar device is known from NL-A-7206052. Accordin to this two beams are present lying one above the other, which are connected with each other with a system of rods and a number of draw-springs and compression springs. The lower rod is provided at the ends, with telescopically slidable rods having pivoting hooks at their outer ends which are connected with the ends of the upper beam,by means of a carrying rope. The rods and springs push the rods with hooks outwardly, whereas the weight of the grab device itself moves the rods with hooks inwardly until the hooks grab around the outer edges of the tube to be grabbed and the grab with tube can be hoisted. The known device has the objections that, as a consequence of the large back pressure when moving outwardly and of the high centre of gravity, the device falls over, owing to which the crane's operating procedure has to start over again before the tube can be grabbed. This causes great loss of time. Besides, the operation of the bolt lock of the rod system is unreliable, which once more decreases the dependability.

The aim of the invention is the removal of these objections and the provision of a grab device of the above- mentioned kind which is reliable, is suitable for the transportation of heavy tubes of steel, also under arctic circumstances and which can be connected and/or disconnected exclusively by means of the operating procedure of the crane by the crane-driver, without hydraulic pipes or other controls between the grab and the crane-driver being necessary.

According to the invention this aim is attained by the measure according to the characterizing part of claim 1.

By the application of the invention one obtains a small back pressure of the outward movement of the hoisting hooks at a low structural height of the grab itself, whereby

OMPI a reliable operation is attained by exclusive operation control by the^* crane's operating procedure by the crane driver, so that on account of the lack of operation control on the tube itself, the grab is suitable for arctic weather conditions, during which the tube can be slippery, either by snow, ice or glazed frost.

DE-C-196.162 relates to a grab for concrete tubes comprising a central, vertical hydraulic lifting cylinder, to which a number of grab rods have been connected. Special dampening means for the hydraulic system are lacking here.

US-A-789.716 relates to a grab with pneumatic operation control outwardly and spring pressure inwardly. The special dampening is missing also here, whereas the air operation on the one hand produces suddenly engaging forces making the reliable grabbing uncertain and is on the other hand unsuitable for arctic operations by the danger of freezing of the pipes.

DE-B-1.293.433, it is true, shows hydraulic operation control for the long downwardly extending arms, but the hydraulic system is very complicated in comparison with the simple dampering means according to the invention.

The invention will now be elucidated by means of the enclosed, drawing of some embodiments.

Fig. 1 shows a side vie--7 of the grab device according to the invention for the transportion of tubes, whereby the suspension cables have been represented in a foreshortened way, according to a first embodiment.

Fig. 2 shows on a larger scale a middle section over the grab device of Fig. 1 according to line II-II in Fig. 1.

Fig. 3 and 4 show on the same scale as Fig. 2 cross sections over the lines III-III resp. IV-IV in Fig. l.

Fig. 5 shows a side-view of a second embodiment.

Fig. 1 shows that the grab device according to the invention is constituted by a tubular carrier which is generall indicated by 1 and has a square cross section in the represente embodiment. Since the grab is symmetric around its centre plane situated in the cross section II-II in Fig. 1, only one half of the device will be described, since the other half is

OMPI IPO performed symmetrically.

In the carrier tube 1, which in the centre is provided with a rim flange, with which the halves can be connected by means of detachable fastening means, such as bolts and nuts, is situated a tubular arm 3 having pairs of guiding wheels 4 resp. 5 on its upper side and lower side, so that the arm 3 is axially slidable in and out. The cylinde 6 of a hydraulic piston-cylinder-unit is connected in the arm 3, whereas the piston 7 thereof has been secured against displacement in the centre surface. A hook 9 which is pivota around a horizontal shaft with joint 8 has been attached to the outer end of the arm 6 being slidable inwardly and outwar the jaw or opening of the hook being directed towards the centre of the support 1 and being situated on the lower side of said support. The inwardly directed point of the hook 9 supports a wheel 11 rotatable around a horizontal shaft 10. At its outer side the hook 9 is moreover provided with a buff 12, which for instance can be made as a pneumatic tyre which rotatable around a horizontal shaft 13. This buffer 12 protec the hook 9 against side-pushes.

The hydraulic piston rods 7 are preferably hollow in order to constitute a supply and discharge channel towards the inner space of the cylinder 6. This channel 14 is connect via (not represented) means to an accumulator 15 for hydrauli liquid, preferably containing also a gas under pressure, such as nitrogen. These accumulator vessels 15 have been connected, by means of brackets 16, to the side walls of the support 1. In the hydraulic connection is present at least one (not represented) throttle place taking care for at least the dampening of the inward movement of the cylinder 6 and consequently of the hooks 9.

Such as is shown in Fig. 4, the support 1 is preferab provided on both sides with support legs 17. These support leg 17 are able to pivot around horizontal shafts 18 extending parallel to the longitudinal direction of the support 1. The shafts with joints 8 have been attached in support leg gins 19, which themselves have been connected to both sides of the support and offering the opportunity to connect the support le 17 in an adjustable way, so that these support legs can be_^ adjusted on the^' relating diameter of the tube to be transporte The consequence thereof is that then the hook 9 always grabs in the correct position into the tube.

At their lower sides the support legs 17 are provided with antifriction members 20 consisting preferably of wheels, the running surfaces of which is able to roll of wheels, the running surface of which is able to roll over the tube 21 to be transported, in such a way that the support 1 can always be placed with its centre plane as much as possible in the centre plane of the tube to be transported 21.

Although the represented embodiment only represents one support 1, which on every end is provided with a hook with jaw, as a consequence of which only one tube 21 can ever be transported, it will be clear that the grab device accordin to the invention can also be execute plurally, so that, for instance, two or more supports have been connected one beside the other, which simultaneously are able to transport two or more tubes.

The hoisting means preferably comprise pulleys 21 connected on both sides of the support to the shafts with joints 8, said pulleys on the one side being solidly connected to the lifting hook 23, and on the other side to an eye 24 positioned above the support in the middle surface, by means of a continuous cable 22. This eye 24 is again solidly connected with the lifting hook 23 by means of a vertical cable 25 having a fixed length. This lifting hook 23 is operated by the lifting cable 26 which is connected to a hoisting apparatus (not represented) . This suspension of cable has the advantage that when the whole hoist, consisting of the suspended support with the load attached thereto and formed by the object, such as a tube of steel, is eased off on one side on an obstacle, such as a hatch-coaming of a seaship or something like that, this load can make a considerable angl with the horizontal without the risk existing that the hooks 9, by the decrease of the horizontal locking force, move outwardly under the influence of the spring means and release the tube at an undesired and dangerous point of time. The crane driver who is warned by the oblique position can then hoist the load again and thereafter ease off the hoist in the

OMPI WIP correct way in the almost horizontal position, so that the disconnection of the hooks does not take place prematurely, but exclusively takes place on the desired spot and at the correct time. Fig. 5 shows a second embodiment of the invention, according to which the tubular support 31 connected to the hoisting hook 23 is shear-shaped and is provided with the hinging shear arms 31a and 31b. A hydraulic piston-cylinder unit 33 is hingeably connected between the upper ends of the arms 31a, b. The width of opening of the shear can be adjusted by means of that hydraulic piston-cylinder unit 33. The supply vessel 36 for hydraulic liquid is accommodated in one of the arms, here arm 31a. A balance beam is connected between the hoisting hook 23 and the shear arms 31a, b. The extremities of this balance beam are connected to the hooks 9a,b by means of wire cables 35a,b; said hooks grab on the tube 21 to be hoisted. These hooks 9a, b are connected to the extremities of the hook arms 3a, b which are hingeably connected to the lower ends of the shear arms 31a,b. Furthermore each of the hook arms 3a,b carry an antifriction member 20a,b for the easy displacement over the tube 21. The hinge point 32 of the shear arms at the lower side is provided with a fixed support, with which the gripper can support on a movable car (not represented In principle the operation of this second embodiment is similar to that of the first embodiment according to Figs. 1-4.

OMPI

Claims

1. Grab device for the transportation of objects, such as oblong tubes, provided with a support which can be displaced by means of hoisting means, and which is provided with at least two jaw means, each being situated near to an end and each being pivotable around a horizontal axis, for the grabbing of an object, the jaw means (9) on the one side each being under the influence of a spring device (15) which tries to move the jaw means outwardly and on the other side during hoisting each are subjected to an inward force exerted by the hoisting means (22-25) , characterized in that spring dampening means are present for the retardation of at least the inward movement of the jaw means (9) .

2. Grab device according to claim 1, characterized in that the outward force of the spring means is smaller, preferab an order of magnitude, than the inward force exerted by the hoisting means (22-25) .

3. Grab device according to claim 1 or 2, provided wit fluid means for the control of the jaw means, characterized in that the fluid means comprise at least one piston-cylinder unit (6,7) which is connected to a fluid accumulator (15) which is also filled with an other fluid under pressure.

4. Grab device according to claim 1 or 2, characterize in that the spring damping means in the connection between the cylinder (6) and the fluid accumulator (15) comprise at least one throttle place.

5. Grab device according to one or more of claims 1 to 4, characterized in that a hydraulic medium is used as fluid.

6. Grab device according to one or more of claims

1-5, characterized in that the support comprises a tube (1) which guides arms (3) which are telescopically slidable inwardl and outwardly, said arms each supporting at their extremity a hingeable jaw (9) .

7. Grab devuce according to ine or more of claims 1 to

6, characterized in that the support tube (1) has one or more antifriction members (20) with which it can move over the objec to be transported for the positioning of the jaws (9) with respect to the object (21) .

8. Grab device according to one or more of the preceding claims 1 to 7, characterized in that the antifricti members (20) have been placed on support legs (18,19) protrud from the support in a transverse downward and an oblique downward direction.

9. Grab device according to one or more of the preceding claims, characterized in that the antifriction members (20) are wheels, the axis of which crosses that of the object to be transported preferably perpendicularly.

10. Grab device according to one or more of the preceding claims 1 to 9, characterized in that the hoisting means comprise a pulley (21) connected to each jaw (9) , which by a continuous cable (22) one the one side is fixedly connect to the hoisting hook (23) and on the other side to an eye (24) disposed in the horizontal position of the support (1) in the centre between the pulleys (21) higher than the pulleys (21) , said eye being solidly connected to the hoisting hook (23) by means of a vertical cable (25) having a fixed length.

11. Grab device according to one or more of the proceding claims, characterized in that each arm (3) is connec to the extremity of a fluid cylinder (6) , the piston (7) of which is solidly connected to the inner side of the support (1 whereas the fluid connection with the inner side of the cylind (6) takes place via the hollow piston (7) .

12. Grab device according to one or more of the claims 1 to 11, characterized in that the jaws (9) each at the outer side carry a wheel (13) , which is rotatable around a horizontal axis, with air tyre serving as buffer, and the shaft line of which extends parallel to the shaft line of the support (1) .

13. Grab device according to one or more of the preceding claims, characterized in that the support tube (31a, is shear-shaped, while near the hinge point (32) of the shear arms a hydraulic operating cylinder (33) has been connected- hingeably which pushes the shear arms in an outward direction.

14. Grab device according to claim 13, characterized in that the hinged connection of the shear arms (31a,b) has been connected to a balance beam (34) , which at the outer ends is connected to the hooks (9a,b) grabbing on the tube (21), by

- TJREΛ

OMPI means of cables (35a,b) .

15. Grab device according to one or more of the claims 13 or 14, characterized in that the arms (3a,b) are hingeably connected to the lower ends of the shear arms (3la,b)

16. Grab device according to one or more of the claims 13-15, characterized in that the hook arms (3a,b) suppo the antifriction members (20a,b) at the lower side.

17. Grab device according to one or more of the claim 13-16, characterized in that the balance beam (34) is solidly connected to the hoist.

18. Grab device according to one or more of the claim 13-17, σharacteruzed in that the supply vessel (36) for the hydraulic liquid is accommodated in one of^' the shear arms (35a)

OMPI