US3008587A

US3008587A - Traveling crane for precise operation

Info

Publication number: US3008587A
Application number: US809486A
Authority: US
Inventors: Dachkevitch Vsevolod
Original assignee: Commissariat a lEnergie Atomique CEA
Current assignee: Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Priority date: 1958-05-06
Filing date: 1959-04-28
Publication date: 1961-11-14
Anticipated expiration: 1978-11-14
Also published as: LU37145A1; FR1238236A; CH350095A; DE1130978B; GB917137A; BE578104A

Description

MlOZA XR sgoomsav "kW Nov. 14', 19 1 y. DACHKEVITCZZH 3,008,587

-' TRAVELING CRANE FOR PRECISE OPERATION Filed April 28, 1959 3 Sheets-Sheet l Nov- 1 v. DACHKEVITCH TRAVELING CRANE FQR PRECISE OPERATION Filed April 28, 1959 5 Sheets-Sheet 2 FIG.3

Nov. 14, 1961 v. DACHKEVITCH 3,008,587

TRAVELING CRANE FOR PRECISE OPERATION Filed April 28, 1959 3 Sheets-Sheet 3 3,008,587 TRAVELING CRANE FOR PRECISE OPERATION Vsevolod Dachkevitch, Nenilly, France, assignor to Cornmissariat a lEnergie Atomique, Paris, France Filed Apr. 28, 1959, Ser. No. 809,486 Claims priority, application France May 6, 1958 7 Claims. (Cl. 212-129) The present invention relates to a traveling crane for precise operation in which precision is obtained automatically without intervention by the operator for adjusting the position of the mobile elements.

This apparatus may be employed for performing cycles of operation automatically or semiautomatically. It may also serve for handling dangerous substances, for example, radioactive substances, because the operator can control operation from a protective shelter which prevents him from seeing the apparatus in operation.

The traveling crane of the present invention has a hoisting assembly divided into two superposed elements, which can be connected with each other or moved relatively to each other, the upper element having a member mounted in guide tracks, both stationary and mobile. The mobile tracks are connected to a movable carriage and by movement of the carriage form prolongations of the fixed tracks, the lower element having centering means with respect to the axis of lifting of the load.

The operation of this apparatus is to easy to understand. During movement of the carriage the guides connected with the carriage are employed for limiting the gratory or oscillatory movement of the hoisting assembly whose two elements are connected.

Movement of the carriage is arrested by any suitable. means when the mobile guides form prolongations of the fixed guides. Precise positioning of the carriage is unnecessary. All that is necessary is either that the guide member of the hoisting assembly sliding along the guides be able to disengage from the mobile guides and engage in the stationary guides or the reverse. To this end relatively great play may be provided between the guides and the hoisting assembly at the opposed ends of the stationary and mobile guides.

The carriage being at rest, the movement of the hoisting assembly in the vertical direction can be performed. The stationary or mobile guides damp its parasitic movements and adjust its trajectory.

However, the amount of freedom of the guided hoisting assembly cannot be made large enough for good centering with respect to the load. It is important that play in guidance be small so that the movement of the hoisting assembly will be stable and precise. The play should be smaller than the play between the load and its support especially for precision of placement of the support in the case of a mobile support.

The division of the hoisting assembly into two elements, which can be connected with each other or be movable relative to each other, permits the lower element, when released, to have sufficient freedom to center itself by means supported on the load or by means of the load contacting the support on which it is to be placed.

The division of the hoisting assembly into two superposed elements has another advantage. It creates two superposed zones of manipulation communicating through small openings. For this purpose the lower element may be of small size to pass from the upper to the lower zone or conversely. In this way the upper zone remains free for handling of cumbersome objects.

According to one embodiment of the present invention, the hoisting assembly is suspended on a lifting cable having a fixed end with the other end wound on a winch. The cable is rove off as a tackle having n 3,fili8,587 Patented Nov. 14, 1961 pulleys mounted on the upper element of the hoisting assembly and 11 plus 1 pulleys mounted on the lower element of the hoisting assembly where n is any suitable number. Stops limit the descent of the upper element. Centering of the two elements is provided by telescoping male and female members of suitable shape, such as conical.

The tension of the lifting cable due to the weight of the hoisting assembly maintains the two elements in contact with each other in the absence of a deliberate relative displacement of the elements. During a descent, if movement of the upper element is arrested by the stops, the lower element continues to descend alone. However, for a given velocity of unwinding of the lifting cable, the velocity of the lower element is only a fraction equal to (l)/(n+1) of what it would be if the two elements were connected. Descent of the lower element in the lifting axis is assured by the parts of the lifting cable, which form the tackle between the two elements of the hoisting assembly and the reduction of the velocity of descent increases the stability of its trajectory.

Analogously, on ascent only the lower element is at first lifted at slow speed. When the lower element rejoins the upper element it is automatically positioned in proper relation to the upper element and bears against it and lift is at normal speed, the effect of the tackle being eliminated by the union of the two elements of the hoisting assembly into a single mechanism.

In an embodiment of the traveling crane of the present invention, control of the locking and unlocking of gripping members is provided by mechanism sliding on the lower element of the hoisting assembly and connected by a tackle, similar to the lifting tackle and disposed between this mechanism and the upper element of the hoisting assembly, with a locking cable having a fixed end with its other end wound on a winch. Adjustment of the tension of this cable is obtained by two suitable devices, such as springs, counterweights or pneumatic jacks. One such device which is capable of exerting a force smaller than that necessary for unlocking the gripping members is employed in the locked position and the other device unlocks and maintains the gripping members in unlocked position.

In another embodiment, the tension of the locking cable is adjusted in the locked position by an auxiliary movable counterweight, whose upward movement is limited by a stop; and, in the unlocked position, by another mechanism, for example, a pneumatic jack, which blocks the counterweight against the stop and controls the unlocking of the gripping members.

The mechanism described above prevents relative displacement of the lower element of the hoisting assembly and of the locking arrangement of the load sliding on this element during vertical movements of the hoisting assembly. The position of the lower element of the hoisting assembly, therefore, determines the moment for hooking or unhooking the load.

The action of the winch simultaneously winds or unwinds theoretically equal lengths of the lifting and of the locking cables, displacing by the same amplitude the locking arrangement of the lower element of the hoisting assembly, these mechanisms being connected to the respective cables by similar tackles. However, differences in diameter of the cables due to differences in construction; differences of diameter of winding between two zones of the drum caused by the two cables due to unequal workmanship; and different wear of the grooves may produce relative movement between the lifting and the locking cable. Friction and seizing of the cable on obstacles because of excessive bending in the unlocked position, and locking of the gripping mechanism may prevent engagement with the load. Excessive tension may cause, in the locked position, premature unlocking of the load and, in the unlocked position, breaking of the cable.

It is therefore desirable to absorb variations in the tension of the locking cable due to the relative movement of this cable with respect to the lifting cable. Two arrangements are necessary, one for the tension corresponding to the locked position, and the other for the higher tension corresponding to the unlocked position. This latter arrangement also regulates the locking and unlocking of the gripping members.

The first of these arrangements may be an auxiliary movable counterweight having its upward movement limited by a stop which counterweight is displaced to absorb variations in the length of the cable. The second arrangement may be a pneumatic jack which blocks the auxiliary counterweight against its stop, overcomes resistance opposing the unlocking action and regulates the tension in the cable and maintains it constant.

The traveling crane of the present invention may have a plurality of hooks for engaging and locking with the load. Three hooks are preferred and are articulated on the lower element of the hoisting assembly and are supported on an inner flange projecting toward the interior of the load.

This arrangement is utilized when hollow bodies such as receptacles are to be handled.

The hooks or claws described above spread into engagement with the load and so do not increase the dimensions of the load enabling the load to be passed through smaller openings and placed in smaller receptacles.

It is necessary and sufficient to seize the load at three points to avoid any relative movement between the load and the gripping members.

The operation of the traveling crane of the present invention is automatic or semiautomatic when handling objects of the same or nearly the same form and dimensions which are to occupy predetermined positions. The movement of translation of the carriage, the ascent and descent of the hoisting assembly, the locking and unlocking of the load, can, for example, be controlled by contacts placed along the paths of movement of the carriage and of the hoisting assembly to close or open electric circuits and actuate relays energizing the driving mechamsms.

With reference to the accompanying drawings and to FIGS. 1 to 4 thereof, in which like reference characters indicate like parts, there will now be described an illustrative embodiment of the traveling crane of the present invention. The constituents and arrangements described in connection with this embodiment are to be regarded asconstituting a part of the invention, it being understood that equivalent structures may be used without thereby departing from the scope of the invention.

In the drawings:

FIG. 1 is a schematic showing of one embodiment of a traveling crane according to the present invention;

FIG. 2 shows, on larger scale, the hoisting assembly of the traveling crane of FIG. 1;

FIG. 3 is a schematic view of the guides on the line I--I of FIG. 2; and

FIG. 4 shows the relationship of the carriage and guide tracks with the hoisting assembly positioned on the guide tracks.

In FIG. 1, a treating shop for dangerous materials, for example, radioactive materials is shown. This shop is divided into three compartments; the garage A; the colfer B; and the treating bay C, which are separated by doors D and D, respectively, operated in any suitable manner. Garage A has a hatch B through which the tubs 1 are introduced into the treating bay C, these tubs being made in such a way that they can be seized by the gripping members of the traveling crane.

A control desk F for the traveling crane is located outside of the treating shop. It is equipped with a synoptic board for observation of the operations proceeding in the treating shop.

In tubs 1, substances are treated which are manipulated with the help of special open receptacles 2, called baskets. Each basket 2 is brought to and taken away from the shop by a carriage 3, provided with a receiving container 4 which is disposed beneath entrance hatch 5. Hatch 5 is provided with an automatic system, not shown, which closes compartment B after basket 2 has entered it. Each basket 2 is provided at its top with an outer flange 6 by which it is suspended in tubs 1 or receptable 4. Each basket 2 is provided with an inner flange 7 by which it is seized by the hooks of the lifting apparatus.

The operations to be performed are the transfer of a basket 2 from receptacle 4 to one of tubs 1 or from one tub I to another.

For this purpose a traveling crane is provided having a carriage 8 mounted on rollers 9 carried in track 10. Movement is obtained by cable 11 under tension by counterweight 12, guided by various transmission pulleys 13, and tensioned by winch 14.

Carriage 8 suspends hoisting assembly 15 Whose movement is directed by guides 16 connected to carriage 8 and by guides 17 which are mounted to the right of the axes of tubs 1 and of batch '5.

Guides

16 and 17 consist of angles spaced apart to provide a groove or slideway. The groove or slideway is widened at the lower part of guides 16 and at the upper part of guides 17 to facilitate transfer of hoisting assembly ,15 if the

guides

16 and 17 are not perfectly aligned. Stops 18 at the lower end of the guides 17 for hatch 5 limit the movement of the guide member of hoisting assembly 15.

As can be seen in FIG. 2, swingbar 15 comprises an upper element 15-A and a lower element Iii-B.

As shown in FIGS. 2 and 3, upper element 15A consists of a guide traverse 19 comprising a frame extended by two lateral wings whose ends 24) engage in

guide grooves

16 and 17. Traverse 19 carries supports 21 and 22 for two superposed

pulleys

23 and 24.

Lower element 15B consists of plate 25 carrying frames 26 supporting two coaxial pulleys 27, and spaced by horizontal frame 28. Frame 28 is centered on traverse 19 by means of

elements

29 and 39 of conical form telescoping in each other providing alignment of the two ele ments of hoisting assembly 15.

Three hooks 31, arranged at relative to each other are articulated on plate 25 and are controlled by lever arms 32. Hooks 31 seize basket 2. For sake of clarity in the drawing, only one book 31 is shown in FIG. 2.

Plate 25 carries axially a sliding arrangement for controlling hooks 31, which includes pulley support 33, mounting two identical pulleys 34 and connected by rod 36 to counterweight 35. Movement of rod 36 is limited in one direction by pulley support 33 and in the other by stop 37. The end of lever arm 32 is mounted between counterweight 35 and plate 38. counterweight 35 is provided with three fins 39, one only being shown, guiding the lower element 15-8 of hoisting assembly 15 relative to basket 2, when the hooks 31 are re opened. Fins 39 are placed at 120 relative to each and at 60 relative to hooks 31.

Hoisting assembly 15 is suspended from carriage 8 by lifting cable 48. Cable 40 is fastened at its end 41 and passes in succession over transmission pulleys 42 mounted on carriage 8; then over one of the pulleys 27; then over pulley 23; then over the second pulley 27; then over the second pulley 42; then over transmission pulley 43; and then leads onto winch 44.

The locking arrangement above described is controlled by cable 45. Cable 45 is fastened at one end 46 and passes in succession over one of the pulleys 47; then over one of the pulleys 34; then over pulley 24; then over the second pulley 34; then over the second pulley 47; then over transmission pulley 43; then over pulley 49, carrying auxiliary counterweight 50; then over pulley 51 carried by stationary pneumatic jack 52; and then leads onto winch 44. Auxiliary counterweight th is. lighter than counterweight 35 and its upward movement is limited by stop 54 on housing 53 in which it is located. Jack 52 exerts on cable 45 a force sufficient to displace counterweights 35 and 59, locking or unlocking hooks 31.

Movement of carriage 8 by winch 14 is elfected when ,hois-ting assembly 15 is in its upper position with guide traverse 19 engaged in guides 16.

Movement is stopped when guides 16 are opposite one of the sets of fixed guides 17. The descent of hoisting assembly 15 is then started by actuating winch 44. During descent auxiliary counterweight 50 or pneumatic jack 52 maintains constant tension on locking cable 40.

When lowering into receptacle 4, when the upper element 15-A of hoisting assembly 15 encounters stops 18, its movement is stopped, and lower element 15-13 continues to descend alone but at half speed only. Descent of element 15-B is arrested when basket 2 is placed in receptacle 4 or when hooks 31 are at the level of flange 7 of basket 2 which is indicated by the position of element 15-B. Locking or unlocking of basket 2 is then completed. The ascent of hoisting assembly 15 is then begun and lower element 15-B rejoins element 15-A, contacts and lifts it until hoisting assembly 15 is in position for horizontal movement which is indicated by the position of upper element 1 5-A.

When basket 2 is lowered into one of tubs 1, hoisting assembly 15 is stopped when basket 2 is placed in tub 1 or when hooks 31 are at the level of the inner flange of basket 2 which is indicated by the position of the upper element 15-A.

The various operations are started or stopped according to the position of element =15-A or element 15-B of hoisting assembly 15. Suitable means located at suitable places, for example, electric contacts, represented schemmatically at 55 of FIG. 2, indicate the position of basket 2 or of hooks 31, and may start or stop any operation or group of operations. Automatic operation is possible because of the precision with which movement of the various elements of the traveling crane can be obtained.

It should now be apparent to those skilled in the art that the several objectives discussed above are obtained by the present invention.

Changes in or modifications to the above described illustrative embodiment of the invention may now be suggested without departing from the inventive concept and reference should be had to the appended claims to determine the scope of the invention.

What is claimed is:

1. In a traveling crane for precise operations, a carriage, a hoisting assembly, two superposed elements in said hoisting assembly, means for connecting said elements to each other and for moving said elements relative to each other, a guide for the upper element of said superposed elements, vertically disposed guide tracks for said guide, said guide tracks comprising fixed guide tracks and movable guide tracks mounted on said carriage and form ing extensions of said fixed guide tracks, said guide engaging arid running on said guide tracks, and centering means on the lower element of said superposed elements centering said lower element with respect to said upper element and to the lifting axis of the load.

2. A traveling crane as described in claim 1, in which said hoisting assembly is suspended by a lifting cable, means fixing one end of said cable, a lifting winch receiving the other end of said cable, the bight of said cable being rove off in a tackle, pulleys for said tackle mounted on the upper element of said superposed elements and pulleys for said tackle mounted on the lower element of said superposed elements.

3. A traveling crane as described in claim 2 including male and female members of.conical form carried by and centering the lower element and the upper element of said superposed elements.

4. A traveling crane as described in claim 2 including gripping members on said lower element and means for controlling the locking and unlocking of said gripping members mounted on said lower element, including a tackle similar to said lifting tackle and disposed between said controlling means and the 'upper element of said superposed elements and rove ofi from a locking cable having a fixed end and its other end led to said lifting winch.

5. A traveling crane as described in claim 4 including means for regulating the tension of the locking cable comprising two tensioning mechanisms, one of said mechanisms exerting a tractive force smaller than required for releasing said gripping members, for maintaining said gripping members in locked position and the other of said mechanisms exerting a tractive force sufiicient to unlock and hold said gripping members in unlocked position.

- 6. A traveling crane as described in claim 4 including an auxiliary mobile counterweight whose upward movement is limited by a stop regulating the tension of the locking cable in the locked position, and a pneumatic jack blocking said counterweight against said stop in unlocked position and unlocks said gripping members.

7. A traveling crane as described in claim 4 including a plurality of hooks locking the load and articulated on said lower element of said hoisting assembly and mounted for reception within the interior of the load.

References Cited in the file of this patent UNITED STATES PATENTS 1,570,035 Bennington Jan. 19, 1926 2,457,135 Deiters Dec. 28, 1948 2,615,588 Gedris Oct. 28, 1952 2,689,661 Przybylski Sept. 21, 1954 FOREIGN PATENTS 416,781 Great Britain Sept. 18, 1934