GB2186256A

GB2186256A - Cradle handling system

Info

Publication number: GB2186256A
Application number: GB08602997A
Authority: GB
Inventors: Robin William Hickey Coghlan
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-02-06
Filing date: 1986-02-06
Publication date: 1987-08-12
Also published as: GB8602997D0; GB2186256B

Abstract

A cradle handling system, for example a steel stockholding system, comprises a number of stackable cradles. Each cradle includes four upright members (14), and through the upper end of each of these is formed a bore (15). In use, the lifting gear is lowered over a stack of cradles, with the aligned sets of uprights (14) being received between four sets of vertically extending guide rails (36, 38). The lifting gear is positioned so that the pegs (42) are aligned with the bores (15) of the cradle whose contents are needed. The pins (42) are inserted into the bores (15) by operating a remote pneumatically-operated switch, and the entire stack of cradles including and above the chosen cradle can be lifted at once. <IMAGE>

Description

SPECIFICATION Cradle handling system The invention relates to cradle handling systems and is particularly, though not exclusively, useful in the field of steel stockholders.

The conventional method of storing and handling steel sections, bars and tubes is to use a system of stackable racks. The racks comprise simply two uprights and a lower cross member and are used in pairs one at each end of a bundle of steel. In each pair of racks may be stored a different product which is lowered onto the racks by an overhead crane. The racks themselves are positioned and removed by hand. The disadvantages of this method are that if one wishes to obtain access to the product in the pair of racks at the bottom of the stack it is necessary to lift off one by one, all the material and the racks above it. This obviously wastes a considerable ammount of time and also presents considerable dangers to the operator who is required to enter the system to remove and replace the racks.

One system which has been proposed to overcome these difficulties uses a series of interlocking cradles, each of which may be attached to the one above and below it by means of manually operated pins. With this system several cradles can be locked together and when the topmost cradle is lifted by an overhead crane all the cradles are lifted as a single unit. This system, while at least partially overcoming the problems mentioned above, has the disadvantage that, when several cradles are to be lifted at once, each must be separately linked to the one above it by means of a manually operated lever. Furthermore, since each cradle must include means for locking it to an adjacent cradle, the individual cradles are complicated and therefore expensive.

It is an object of the present invention to attempt to alleviate these problems.

According to a first aspect of the invention a cradle handling system comprises a plurality of stackable cradles, and lifting means including fastening means for fastening the lifting means to a selected cradle in a stack, whereby lifting of the selected cradle by the lifting means also lifts all the cradles in the stack above the selected cradle.

According to a second aspect of the invention, a cradle lifting device comprises a rigid lifting frame, a pair of rigid upright spars rigidly secured at spaced points to each side of the lifting frame and depending from the lifting frame to straddle a stack of cradles, and remotely operable fastening means adjacent the bottom of each spar adapted to attach the spar to a cradle.

According to a third aspect of the invention, a method of operating a cradle handling system having a plurality of stackable cradles which are not vertically coupled to one another comprises fastening lifting means to a selected cradle below the top cradle in a stack, and lifting both the selected cradle and hence also all the cradles in the stack above the selected cradle.

The present invention is particularly advantageous when used with a system in which a large number of cradles are needed. This is because the cradles used in the present invention can be of a simple and cheap construction. In fact, the cradles may be simple containers of any sort, and may vary according to the product that is to be stored within them.

Instead of an expensive locking mechanism being provided on each individual cradle, a single locking mechanism may be provided, on the lifting gear. Furthermore, in lieu of manual locking means, the invention may provide for electrically, pneumatically or hydraulically controlled locking which may be remotely operated.

The invention may be carried into practice in various ways and one specific cradle handling system and its method of operation will now be described with reference to Figs. 1 to 8, in which Figure 1 is a diagrammatic end view of a cradle handling system; Figure 2 shows an individual cradle suitable for the system of Fig. 1; Figure 3 shows an alternative form of a cradle; Figure 4 shows another alternative form of a cradle; Figure 5 shows lifting gear suitable for the system of Fig. 1; and Figure 6 shows a section of one lower corner of the lifting gear with the locking mechanism withdrawn.

Figures 6A and 6B show front and rear pin guides.

Figure 7 shows the same section as Fig. 6 but with the locking mechanism engaged into a cradle.

Figure 8 shows a floor spacer for ensuring that the cradle stacks are level and correctly separated.

Fig. 1 shows, diagrammatically, an end view of an embodiment of a cradle stacking system according to the invention. In the example shown there are four stacks 10, each comprising six cradles 12. Each cradle 12 holds a particular product; in the case of a steel stockholding system these may be, for example, various sizes and lengths of steel section, bars and tubes. The cradles 12 may be of various sizes and shapes according to the material to be stored. A basic cradle is shown in Fig. 2; this comprises simply four tubular upright members 14 having aligning spigots 16 welded at their upper ends. When the cradles are stacked one above one another these spigots 16 engage into the bot tom of the tubular upright members 14.The upright members are joined at their lower ends by two cross bars 18 and two stretchers 19; the upright members 14 are attached to the outer faces of the stretchers 19 and the cross bars 18 extend between the inner faces of the upright members so that three of the four faces of each of the upright members is unobstructed. On one of the upright members 14 is fixed a label holder 17 for identification of the material to be stored. Between the two stretchers 19 is welded a flat plate 21 to facilitate slinging and unslinging of the material to be stored and also to give an indication of the central point of the cradle. The actual form of cradle 12 to be used will depend upon the nature of the material to be stored within it. Fig. 3, for example, shows a cradle suitable for long steel bars or the like, where extra support is needed both at the ends and in the middle.The additional central support is provided by means of two central cross bars 22, and the end support is provided by making the stretchers 20 longer and joining them at the ends by additional end cross bars 24. A further type of cradle is shown in Fig. 4. This includes two supporting troughs 26 on central supports 27 and is useful where complete support of the product is required, for example very small diameter bars, without restricting access to the material for slinging and unslinging. The various types of cradle may be arranged so that they are compatible with each other, allowing, if necessary, all of them to be used within the same stack. In each case the cradles are provided with four bores 15 passing through the upper ends of the upright tubular members 14.

In order to lift several cradles at once from a single stack, the lifting gear shown in Fig. 5 is used. The gear comprises an overhead crane (not shown), the hook 28 of which is connected to four chains 30 the outer ends of which are connected to the lifting eyes 31 on a fabricated lifting beam 32. The beam comprises three lengths of box section; one longer central length 33 joined to two shorter end cross-pieces 35, 39. Extending downwardly from the lifting beam are four cradle guides 34, each comprising two generally parallel guide rails 34, each comprising two generally parallel guide rails 36, 38. The cradle guides are spaced apart laterally by slightly more than the width of the cradles 12. At their lower ends the cradle guides are joined by pieces of flat steel 37 which act as further guides on the exterior of the lifting gear.Between each pair of cradle guides 34 on the same side of the lifting gear is an encasement 40 which provides bracing for the structure, protection and access to the locking mechanisms. Between each pair of cradle guides 34 on the same end of the lifting gear is a tubular frame 41 which provides bracing for the structure, easy manipulation of the lifting gear and a convenient location for a remote operating switch 43. The tubular frames 41 are designed so that their end members are spaced at a greater distance than the length of the laden cradles 12.

Extending between each of the sets of guide rails 36, 38 at their lower ends is a pin 42. Each of the pins 42 is movable between a position as shown in which it extends between the two guide rails 36, 38 and a position in which it is retracted. To show the operator whether the pins are extended or retracted there is a system of indicators 48 mounted on the end piece 35 of the lifting beam. Each of the four pins is operated by its own pin control mechanism. This may be any type of suitable mechanism, for example an electrically operated, hydraulically operated or, in the example being described, a pneumatically operated system. The pins are operated together by means of a single switch. This may be located on the pendant control of the overhead crane or, as in this example by the switch 43 mounted on the tubular frame 41 of the lifting gear.The necessary power connections are made from the overhead crane via a hook block so to the lifting gear. In this example a high pressure hose 46 supplies compressed air from a compressor (not shown) mounted on the overhead crane. A simple pneumatic connector (not shown) mounted on the hook block 50 enables the high pressure hose to be disconnected if required. A pressure gauge 49 shows the operator when the system is ready to use. One of the hollow end pieces of the beam 39 also acts as an air reservoir in the system.

The lifting gear also includes a built in load cell 45 for weighing the stock.

The operation of the pneumatically controlled pins will now be described using Figs.

6 and 7. These diagrams show the same section of the same lower end of a pair of cradle guides 36, 38, the tubular frame 41 and the locking mechanism encasement 40. In Fig. 6 the locking pin 42 is retracted by the pneumatic cylinder 51 when air pressure is applied to it. The cylinder 51 is powerful enough to overcome the forces of a return spring 52. In this position a "retracted" indicator microswitch 53 is activated by a notch 54 in the locking pin 42 and the operator sees a red coloured flag appear on the end piece of the lifting beam as previously mentioned. The end of the pin 42 is received into a hardened bearing insert 55 formed at the lower ends of the cradle guides 36, 38. It is supported for horizontal movement by a front pin guide 57 and a rear pin guide 58, shown, respectively, in Figs. 6A and 6B. The rear pin guide 58 is formed with a shaped hole which corresponds to a similarly shaped end of the locking pin 42 to ensure that a pair of anti-retraction notches 56 remain uppermost. Fig. 7 shows the locking pin 42 in the extended position when air pressure has been released from the cylinder 51. In this example the pin is engaged through the bore 15 of the cradle 12.

The cradle sits in the anti-retraction notches 56 which thereby prevent the pin 42 being withdrawn accidentally whilst under load. The return spring 52 similarly keeps the pin 42 extended should the air supply fail. In this position an "extended" indicator microswitch 59 is activated by the notch 54 in the locking pin 42, and the operator sees a green coloured flag appear on the end piece 35 of the lifting beam. It will be noted that the high pressure tubing 60, required to activate the cylinder 51, is completely protected inside the tubular frame 41, the cradle guides 36 and 38 and the encasement 40.

Fig. 8 shows a floor spacer which is positioned between the floor and the lowest cradle of the stacks. Its purpose is to provide optimum spacing between stacks and also to level out any irregularities in the floor. This particular example shows a spacer designed to hold four vertical stacks which means that it can be freestanding since at any one time the weight of three vertical stacks will bear down on the spacer and prevent it from moving. The freestanding feature of the design is an advantage when it is desired to move a complete section of stock easily from one part of the warehouse to another. In construction spigots 23 are welded onto two flat sections 25 at particular intervals corresponding to the tubular uprights of the cradles 12. Two flat sections 25 are joined by a pair of stretchers 29 to ensure that the spigots on the pair of flat sections are correctly separated.Thus, spigots 70, 71, 72 and 73 form the location for the four lower corners of the first stack. In a system requiring more than four stacks, floor spacers can be put end to end to make any multiple thereof but give the appearance of being one large system.

The methods of operation of the system will now be described. In order to obtain access to a cradle 62 part way down a stack (see Fig. 1), the lifting gear is first positioned over the stack in question. The pins are retracted (see Fig. 6) and when the four red flags appear on the lifting beam, the assembly is lowered over the stack, the spaces between the guide rails 36, 38 accomodating acting the upright members 14. The lifting gear is then positioned so that the pins 42 are slightly above the corresponding bores 15 of the desired cradle 62. The pins are released so that the return springs 52 push them against the uprights of the cradle. The assembly is then lowered again until each of the pins becomes aligned with its corresponding bore and jumps through under the pressure of the return spring 52 (see Fig. 7). Four green flags now apper on the lifting beam.

Each pin is now in a position where it extends from a guide rail 36 through the bore 15 to the corresponding guide rail 38 securely locking the cradle, at four points to the lifting gear. In this position the entire stack of cradles comprising the desired cradle 62 and those above the desired cradle can be lifted as one unit, as is shown in Fig. 1. The cradles above the cradle 62 are not attached together but are stably held by virtue of the fact that the uprights 14 rest between the guide rails 36, 38. To obtain access to the contents of the cradle 62, the whole unit is lifted and then lowered to a convenient place.

The pins are then withdrawn, the lifting gear raised slightly and the pins replaced in the cradle 64 immediately above. This cradle and the stack above it is then lifted and returned to the place from which it came, leaving the cradle 62 behind.

An alternative method of operation is as follows. To obtain access to a cradle 66 (see Fig. 1), the pins are inserted into the cradle 62 immediately above it, and that cradle, and the rest of the stack, temporarily removed.

The lifting gear is then uncoupled from the cradle 62, and returned to lift the desired cradle 66 to the place where it is needed. It is then uncoupled from the cradle 66, recoupled to the cradle 62 and used to replace this cradle, and the stack above it, in its original place.

It will be appreciated that with this system high packing densities can be obtained since the stacks 10 be very closely spaced. For optimum use of the system the stacks 10 should be vertical.

Claims

1. A cradle handling system comprising a plurality of stackable cradles, and lifting means including fastening means for fastening the lifting means to a selected cradle in a stack, whereby lifting of the selected cradle by the lifting means also lifts all the cradles in the stack above the selected cradle.

2. A cradle handling system as claimed in Claim 1 in which the lifting means includes means for stabilizing the cradles above the selected cradle.

3. A cradle handling system as claimed in Claim 1 or Claim 2 in which the means for stabilizing the cradles comprises guide means extending from the level of the selected cradle to a point above the upper cradle of the stack.

4. A cradle handling system as claimed in Claim 1 or Claim 2 or Claim 3 in which the means for stabilizing the cradles comprises a plurality of rigid guide bars.

5. A cradle handling system as claimed in Claim 4 in which the guide bars are arranged in pairs, a part of at least some of the cradles to be stabilized being received between the or each pair of guide bars.

6. A cradle handling system as claimed in Claim 5 in which four pairs of guide bars are provided, the said parts of the cradles being four vertically-extending members.

7. A cradle handling system as claimed in Claim 6 in which the top or bottom of each member has a lug which is arranged to be received within the bottom of the corresponding member of the cradle above, or the top of the corresponding member of the cradle below, respectively.

8. A cradle handling system as claimed in any one of the preceding claims in which the fastening means comprises a movable member carried by the lifting means which co-operates with a detent on the selected cradle.

9. A cradle handling system as claimed in Claim 8 in which the fastening means comprises a movable pin which is received within a portion of the selected cradle.

10. A cradle handling system as claimed in Claim 8 and in Claim 5 in which the pin, in its fastened position, extends between the pair or one of the pairs of guide bars, and passes through the said portion of the cradle.

11. A cradle handling system as claimed in any one of the preceding claims in which the fastening means is pneumatically operable.

12. A cradle handling system as claimed in any one of Claims 1 to 10 in which the fastening means is electrically operable.

13. A cradle handling system as claimed in any one of Claims 1 to 10 in which the fastening means is hydraulically operable.

14. A cradle handling system as claimed in any one of the preceding claims in which the fastening means comprises several fastenings for simultaneously fastening the lifting means to the selected cradle in a plurality of places, the several fastenings being commonly operable.

15. A cradle handling system as claimed in Claim 14 in which the several fastenings are commonly operable by means of a remote switch, not carried on the lifting means.

16. A cradle handling system substantially as specifically herein described, with reference to the drawings.

17. A cradle lifting device comprising a rigid lifting frame, a pair of rigid upright spars rigidly secured at spaced points to each side of the lifting frame and depending from the lifting frame to straddle a stack of cradles, and remotely operable fastening means adjacent the bottom of each spar adapted to attach the spar to a cradle.

18. A device as claimed in Claim 17 in which each spar consists of two parallel bars to form a guide therebetween.

19. A device as claimed in Claim 18 in which each attachment means comprises a pin having an attaching position in which the pin extends between the parallel bars and a retracted position in which the pin is withdrawn from between the parallel bars.

20. A cradle handling system as claimed in claim 18 and claim 19 in which four pairs of bars are provided, the said part of the cradles

20. A device as claimed in any one of Claims 17 to 19 in which pneumatic control means are provided to operate the attaching means.

21. A device as claimed in Claim 20 in which at least a part of the lifting frame acts as a gas reservoir.

22. A method of operating a cradle handling system having a plurality of stackable cradles, which are not vertically coupled to one another comprising fastening lifting means to a selected cradle below the top cradle in a stack, and lifting both the selected cradle and hence also all the cradles in the stack above the selected cradle.

23. A method as claimed in Claim 22 including the further operations of lowering the selected cradle onto a support, unfastening the lifting means, fastening the lifting means to the cradle immediately above the selected cradle in the stack, and replacing the rest of the stack, other than the selected cradle, in its original place.

24. A method of operating a cradle handling system substantially as specifically herein described.

CLAIMS Amendments to the claims have been filed, and have the following effect: Claims 1-24 above have been deleted.

New claims have been filed as follows: Claims 1-25

1. A cradle lifting device comprising a rigid lifting frame, a pair of rigid upright lifting spars rigidly secured at spaced points to each side of the lifting frame and depending from the lifting frame to straddle a stack of cradles, and remotely operable fastening means adjacent the bottom of each spar adapted to attach the spar to a cradle.

2. A device as claimed in claim 1 in which each spar consists of two parallel bars to form a guide therebetween.

3. A device as claimed in claim 2 in which each fastening means comprises a pin having an attaching position in which the pin extends between the parallel bars and a retracted position in which the pin is withdrawn from between the parallel bars.

4. A device as claimed in any one of claims 1 to 3 in which the fastening means is pneumatically operable.

5. A device as claimed in claim 4 in which at least a part of the lifting frame acts as a gas reservoir.

6. A device as claimed in any one of claims 1 to 3 in which the fastening means is electrically operable.

7. A device as claimed in any one of claims 1 to 3 in which the fastening means is hydraulically operable.

8. A device as claimed in any one of the preceding claims in which the fastening means comprises a movable member which co-operates with a detent on the cradle.

being the four vertically extending members.

21. A cradle handling system as claimed in any one of claims 16 to 20 including a floor spacer arranged to be positioned between the floor and a plurality of stacks, the spacer providing a level base for the stacks and having means for ensuring correct spacing between the stacks.

22. A method of operating a cradle handling system having a plurality of stackable cradles, which are not vertically coupled to one another, comprising fastening lifting means to a selected cradle below the top cradle in a stack, lifting both the selected cradle and hence also all the cradles in the stack above the selected cradle, lowering the selected cradle onto a support, unfastening the lifting means, fastening the lifting means to the cradle immediately above the selected cradle in the stack, and replacing the rest of the stack, other than the selected cradle, in its original place.

23. A method of operating a cradle handling system substantially as specifically herein described.

24. A cradle handling system substantially as specifically herein described, with reference to the drawings.

25. A cradle lifting device substantially as specifically herein described, with reference to the drawings.

9. A device as claimed in claim 8 in which the fastening means comprises a movable pin which is received within a portion of the cradle.

10. A device as claimed in claim 9 when dependent upon claim 2 in which the pin, in its fastened position, extends between the corresponding pair of parallel bars, and passes through the said portion of cradle.

11. A device as claimed in claim 9 or claim 10 in which the pin has at least one notch therein, arranged to receive the portion of the cradle, and to prevent retraction of the pin when under load.

12. A device as claimed in any one of the preceding claims in which the several remotely operable fastening means are commonly operable.

13. A device as claimed in claim 12 in which the several fastenings are commonly operable by means of a remote switch, not carried on the lifting means.

14. A device as claimed in claim 12 in which the several fastenings are commonly operable by means of a remote switch, carried on the lifting means.

15. A device as claimed in any one of the preceding claims having indicator means arranged to indicate the position of the fastening means.

16. A cradle handling system comprising a plurality of stackable cradles, and a cradle lifting device comprising a rigid lifting frame, a pair of rigid upright lifting spars rigidly secured at spaced points to each side of the lifting frame and depending from the lifting frame to straddle a stack of cradles, and remotely operable fastening means adjacent the bottom of each spar adapted to attach the spar to a selected cradle in a stack, whereby lifting of the selected cradle by the lifting means also lifts all the cradles in the stack above the selected cradle.

17. A cradle handling system as claimed in claim 16 in which the lifting spars extend from the level of the selected cradle to a point above the upper cradle of the stack.

18. A cradle handling system as claimed in claim 16 or claim 17 in which each of the lifting sparts comprises a pair of parallel bars, the stack of cradles being stabilized by part of at least some of the cradles being received between each of the pairs of bars.

19. A cradle handling system as claimed in any one of claims 16 to 18 in which each cradle includes four vertically-extending members, the top or bottom of each member having a lug which is arranged to be received within the bottom of the corresponding member of the cradle above, or the top of the corresponding member of the cradle below, respectively.