US2957432A - Trolley for cranes such as tong cranes - Google Patents

Description

TROLLEY FOR CRANES SUCH AS TONG CRANES Filed April 1, 1957 3 Sheets-Sheet 1 INVENTOR BY P641 ATTORNEY 1960 H. J. SCHOREL 2,957,432

mum FOR cam-:s SUCH AS TONG cams Filed April 1, 1957 s Sheets-Sheet 2 F19"- Z 45 as as as a i 3 f I I1 I x r Q1 1% 40 ll 1 I. n I I M @Z M 44 :5 34 I? MEEMBMMA INVENTOR ATTORNEY Oct. 25, 1960 H. J. SCHOREL 2,957,432

TROLLEY FOR CRANES SUCH AS TONG CRANES 3 Sheets-Sheet 3 Filed April 1, 1957 u -m 62 a f; as 3 mp 3 MMWIWW 41 645 ammo/v FE g, E

I L/Qu/p INVENTOR flElvpm/r .721 JCHbfEEL M SYSTEM or F/@. 5 w/f/mur BY 7M JFK/#65 J4- ATTORNEY United States Patent ice 2,957,432 TROLLEY FOR CRANES SUCH AS TONG CRANES Hendrik .I. Schorel, Beverwijk, Netherlands, assignor to Koninklijke Nederlandsche Hoogovens en taal- Fabrieken N.V., Ijmuiden, Province of North Holland, Netherlands, a Dutch limited-liability company Filed Apr. 1, 1957, Ser. No. 649,751 Claims priority, application Netherlands Apr. 4, 1956 5 Claims. or. 105-163) This invention relates to a trolley for soaking pit cranes, ingot-stripping cranes, tong cranes, charging cranes or the like, in which the load in one or more horizontal directions has a more or less rigid connection with the trolley.

It is essential that the tongs, loading arm or the like be able to receive and exercise horizontal forces of some magnitude, e.g. when a fallen block is to be put upright again, when an ingot is to be put in the oven or during work on the truck or Waggon and during the rep-air or maintenance of the oven floors. In addition incidental horizontal impacts on the tongs may occur, e.g. against vertical oven or soaking pit walls. On this account the tong column or the like has to be connected somewhat rigidly to the further parts of the trolley. This involves the disk that with a greater horizontal force acting on the tongs the travelling wheels of the trolley may tip up, i.e. get clear of their tails and drop back thereon with a thud. It is known to prevent this by means of springs in the traverses 'by which the tong column is guided when moving up and down in a guide extending downwardly from the frame of the trolley. Therewith. the horizontal force than can be exercised rigidly with the tong column or the like before the spring are compressed will vary greatly. The force at which the springs are just fully compressed, i.e. the moment at which the tong column begins to form a rigid connection with the trolley, so that the trolley is in danger of tipping up, also varies greatly.

On the traverses little space is available for readjustment, inspection, etc., and for the accommodation of springs of sufficient length. Further, lubrication and maintenance will cause difficulties owing to the considerable heat in the immediate neighborhood of the traverses, while the use of hydraulic springs and gas-liquid-accumulators, etc. is not possible in view of heat with a good deal of breakdown.

With this known structure the sidewise deviation of the tongs up to the moment the trolley tips up in the lowermost position of the tongs is a multiple of said deviation in the uppermost position. The crane attendant will thus lack all sense of judging what he can do with the tongs before this tipping-up occurs.

The tipping-up of the trolley has the drawback of the risk of derailment and of sudden dropping-back of the trolley on the crane girder, which may involve very serious damage and interruption of work.

In practice a further structure is known in which fixed abutments have been provided on the trolley, which fixed abutments are forced against the lower side of the main girders of the crane after the trolley has tipped up a little. The trolley structure, upon tipping up, is thus clamped to the crane structure, which gives rise to very great, unverifiable forces in many essential parts of the crane and trolley structures, in consequence of which much damage and even breakage will occur.

It is also known to fit the tong column with a flange, which is supported on the trolley by means of bolts and 2 pre-stressed springs. This is intended to counteract tipping-up 'of the trolley.

This structure has the drawback that the tong column has a very long unsupported length and is consequently subject to considerable bending when horizontal forces act on the tongs. The column therefore has. to be of very heavy construction or else it w ll become too weak and liable to great danger or breakage.

In order to eliminate the drawback of such known structures and to obtain an improved trolley, which suffices all requirements as to the horizontal forces as indicated above in a safe and reliable manner this invention provides a trolley for soaking pit cranes, ingotstripping cranes, tong cranes, charging cranes or the like, in which the load in one or more horizontal directions has a more or less rigid connection with the trolley, in which trolley at least some of the wheels, by means of which the trolley is adapted to move on its supporting structure on the crane, are fitted so as to be displaceable vertically relative to the frame of the trolley together with wheel bearing means such as wheel casings, having abutments cooperating wi h butments on the frame of the trolley, said abutments being arranged so as to prevent the frame of the trolley to sink appreciably relative to said wheels from the relative position for normal load but to allow the frame to rise with respect to part of the wheels with abnormal horizontal loads, a damping device being fitted between the wheels and the frame to damp downward movements of the frame relative to the wheels at least in that part of such downward movements in'which thesaid abutments are in mutual proximity. By this means great imp-act loads on the rail when the trolley drops back and the consequent risk of breakage of the steelstructure and of various parts of the machinery are avoided. When the trolley tips up, the wheels may thus remain on the rails simply owing to their own weight and that of their supporting structure. Further a spring structure may preferably be fitted between the frame and the vertically movable wheel structure, which spring structure forces the wheels resiliently down relative to the frame and is' arranged with pre-stress between the frame and the wheels when the said abutments'abut. In consequence of this the limiting forces for the tipping-up and the horizontal deviations of the tongs for the uppermost and the lowermost position of the traverse are substantially equal.

If the cabin is fastened inthe usual manner to the frame of the trolley the crane attendant will follow the movements of the tong column or the like, so that he will sense at once what is happening.

' Fora better understanding of the nature of the invention, reference may be had' to the accompanying drawings forming a partof this specification and the following description thereof and showing by way of example only an embodiment of a tong crane for use as a soaking pit crane according tolt'his invention.

In the drawings:-

. Fig. 1 represents a vertical somewhat diagrammatic side elevation and cross section of such a tong crane with bridge and trolley, the tongs operating in a soaking of the hydraulic system of the its-parts essential for this invenfor such a trolley with wheel casings Fig. 6 shows a diagram of a modification of a hydraulic system so as to eliminate the need for separate springs.

In Fig. 1 the two composite girders of the bridge are indicated by reference numerals 1 and 2. One of the end carriages or trucks 3 is shown in this figure and both trucks are provided with track wheels 4 running on stationary tracks 5.

Each girder 1, 2 is provided at its upper end facing the other girder with a rail track 6 and 7 respectively. On these tracks wheels 8 of a trolley, indicated generally by 9, support the trolley so that it is able to run in a.

direction perpendicular to the plane of the drawing on the bridge, which itself is able to run in a direction from left to right and reverse as seen in the drawing.

The trolley 9 has a frame structure, which supports the several driving means for wheels and tongs and a depending guide structure 10, rigidly connected to said frame. A tong column 11 has at its upper end a traverse 12 guided for up and down movement in the guide 10. This traverse 12 is provided with two rope pulleys 13, from which ropes extend upwardly to a hoisting drum 14 on the frame of trolley 9. For sake of clarity said pulleys 13 have been shown one to the side of the other, but in reality they should be imagined to be turned by 90 so that they are seen as a circular body in Figure l.

The tong column 11 at its lower end bears a pair of tongs of usual structure, the tong levers 16 and 17 being guided at 18 and 19 respectively in oblique guides 20 and 21 respectively of the tong column 11. A rod 22 extending through the column 11 in a sense as to be freely slidable longitudinally therein is at its upper end provided with a rope pulley 23 so that it is possible to move this rod upwardly by hoisting a rope from a separate hoisting drum on the trolley. The lower end of this rod 22 is connected by a part 24 to a common pivot 25 of the levers 16 and 17. Said levers are provided with hard bits 26 and 27 respectively. By hoisting the rod 22 upwardly the levers 16 and 17 move upwardly in their guides 20 and 21, so that the bits 26 and 27 move apart and by moving the rod 22 downwardly the bits may move towards one another. The tong structure is conventional and may be of the type disclosed in US. Letters Patent No. 670,317, issued March 19, 1901, to Friedlaender.

A traverse 28 of the same general structure as the traverse 12 is arranged below it in the lower part of the guide 10. It rests on abutments (not shown) in said guide and is able to move upwardly in the guide in the same way as the traverse 12. If the column 11 is moved upwardly so far that the collar 29 on the lower end thereof touches the traverse 28 further elevating of the column 11 takes the traverse 28 along upwardly and it is thus possible to move the tongs entirely into the guide 10.

A soaking pit 30 for keeping an ingot 31 at the desired temperature is shown with the cover removed and the tongs lowered entirely into the pit. The operation of the tongs in lifting the ingot from the pit is well known, as described in the aforementioned Friedlaender patent, for example.

The trolley 9 has an operators cage 32. The traverses 12 and 28 and the guide 10 have their greatest horizontal dimension, shown in Figure 1, in reality at right angles to the plane of this figure, as described above with reference to the pulleys 13. Thus the operator through a window 33 is able to see fully and easily what is happening with the tongs.

The trolley 9 carn'es electric motors, gear boxes, operating means etc. for moving the hoisting drums for operating pulleys 13 and 23. Moreover there is an electric motor 34 on the trolley for driving it by its wheels 8 on the tracks 6 and 7 of bridge 1, 2. The operator from his cage 32 also operates motors for driving the wheels 4 of the bridge for moving it along tracks 5.

Turning now to Figures 2, 3 and 4, these show four side girders 35 of the trolley frame 9, mutually connected by transverse connections in the usual way to constitute a rigid frame. In Figure 2 the driving motor 34 and further driving means for only two of the wheels is shown, the hoisting drums and means for driving them are omitted and so are many other parts not relevant for this invention. The tong column 11 is shown schematically as a circle.

Each wheel 8 is bolted to a gear wheel 36 and is together therewith rotatably supported on a trunnion 37, supported in a stationary manner in a wheel casing 38, embodied substantially as a rectangular box with open top and bottom. This wheel casing 38 has a width smaller than the distance between the two adjacent girders 35 so as to be free to move between said girders. A pivot shaft 39 is supported stationary between said adjacent girders 35. The wheel casing 38 is supported pivotally upon said shaft 39 at 40 and 41. A gear wheel 42 is freely rotatable on shaft 39 but is prevented to move axially thereon. Gear wheel 42 is in engagement with gear wheel 36 bolted to the wheel 8 and is on the other hand in engagement with gear wheel 43, keyed on a driving shaft 44. This shaft 44 is supported in bearings 45, one on each of the girders 35, and is driven through a suitable transmission 46 by the motor 34.

At the end of the wheel casing 38 opposite the pivot shaft 39 this casing is bridged by a bridge 47 and between the girders 35 there is a rigid bridge 48 with a downwardly extending abutment 49. This abutment is provided at its lower end with a layer 50 of material, which is somewhat elastic, such as rather hard rubber.

A piston rod 51 of a hydraulic cylinder 52 engages the wheel casing pivotally at 53 and the cylinder 52 is pivoted to the bridge structure 48 on the girders. Said cylinder 52 constitutes part of the hydraulic damping system, which will be described later with reference to Figure 5.

Closer to the wheel 8 a set of two helical springs 54, arranged side by side, is supported pivotally at 55 by the wheel casing and the central guiding rod 56 of each spring extends slidably through a traverse 57, supported pivotally by the bridge 48 on the girders. The springs 54 are under compression as prestress when the frame of the trolley rests by the abutments 49 on the blidges 47 of the wheel casings. The spring discs 58 at the upper end of the springs are also freely slidable in the traverse 57.

Each wheel casing 38 is also provided with a cam surface 59, cooperating with an electric end switch 60, carried by the stationary bridge 48. Switches 60 may be employed to control bridge driving and trolley driving motors.

Referring now to Figure 5, this shows the four wheel casings 38 with pivots 39, the wheels 8, the abutment bridges 47, the stationary abutments '49, the piston rods 51 and cylinders 52 and the springs 54. The spaces in the cylinders 52 above the pistons are connected by ducts 61 to a manifold 62 so that each duct 61 is always in open connection with a duct 62 com-ing down from a reservoir 63 and this entire system is filled with a suitable hydraulic fluid. The reservoir 63 has a pressure equalising connection with the atmosphere in its cover, such that the gas space above the hydraulic fluid therein is always under atmospheric pressure.

Each duct 61 is connected to its cylinder 52 via a check valve 64 allowing liquid to flow towards the cylinder but not back into the duct 61. This check valve 64 is bypassed by a duct with a small and adjustable throttling" orifice 65 and there is a manometer 66 at the entry of the duct 61 into cylinder 52. At 67 leakage oil can be drained from the cylinder 52.

The operation of the trolley is as follows:

In normal circumstances the trolley 9 rests with its frame by the abutments 49 on the wheel casings 38 and horizontal forces of some magnitude,

If the horizontal force upon thetongs becomes too high, the frame of the trolley. tends to tilt. This means that on one side of the trolley frame this frame moves upwardly. The wheels 8 nevertheless remain on their rail tracks 6 or 7 as the hydraulic fluid is able to flow easily from reservoir 63 to cylinders 52 through check valves 64. Thus the wheel casings at the raised side of the trolley pivot easily about shafts 39. The springs 54 cooperate to urge the wheel casings and wheels 8 down on their rails. During this tilting movement the'pre-stress in the springs 54 is decreased and after the stress therein has become zero the wheel casings are allowed to move further down as the spring discs 58 are able to slide down through their traverse 57. As soon as the cam 59, however, moves the arm of the electric switch 60 downwards the electric current is interrupted as indicated above, so that it becomes impossible for the operator to move the trolley or the crane bridge in the direction in which the trolley would tilt further.

If the horizontal load on the tongs decreases, e.g. by moving the cranebridge or trolley in the opposite direction, the trolley tends to sink back to its horizontal position. The concerning pistons thus press the hydraulic fluid from their cylinders 52 into the ducts 61. The check valves 64 prevent this, so that the fluid flows through the throttling orifices 65 in the bypass. This means, that the lowering of the trolley is damped and that the trolley is lowered slowly, so that it returns only with negligible impact upon the wheel casings through contact of the abutments 47 and 49. I

The springs are stressed at least during the later part of this lowering movement and thus aid in obtaining this effect. So no damage to the crane parts is possible and no derailment of the trolley either.

As the trolley is allowed to tilt within limits, the operators cage 32 will tilt w'th the trolley, and thus the operator will feel immediately that the horizontal load allowable for normal circumstances is surpassed.

The pre-stress of the springs is preferably adjustable, as is also the damping of the damping devices.

The damping devices may be combined with the springs by the application of a hydraulic system in which spring action and damping action are combined, eg. with a single buifer space for all the wheel casings, with gas under pressure or other flexible agents above the liquid in said space. This could be obtained easily be replacing the reservoir by a pressure tank, eg with a piston separating gas and liquid or with a flexible balloon with gas under pressure therein resting on the liquid as shown in Fig. 6.

Some kind of damping should anyhow be provided. It is possible to omit the springs entirely and to insert hydraulic dampers only or to damp with mechanical springs alone. It is also possible to arrange hydraulic damping devices so that they only damp the downward movement when this movement is almost terminated.

It will be clear that the invention is not restricted to the embodiment described above and shown in the attached drawings, but covers also such other embodiments falling within the scope of the attached claims.

What I claim is:

1. A trolley for cranes having load engaging means supported thereon and in at least one horizontal direction having a substantially rigid connection thereto whereby horizontal forces on said load engaging means in said direction are transmitted to said trolley, said trolley comprising frame means, wheel casing means carried by said frame means, wheels connected to said wheel casing means for movement on supporting rail means in a horizontal plane thereon, at least one of said wheel casing means and at least one of said wheels being displaceable vertically relative to said frame means, first abutments carried by said frame means, second abutments carried by said displaceable wheel casing means, said first and second abutments cooperating with one another to prevent the frame means from sinking appreciably relative to said wheels from the relative normal position of means but permitting said spect to at least part of the wheels when said horizontal forces become great enough to separate said abutments, and damping means positioned between the wheel casing means and the frame means to damp downward movement of the frame means relative to the wheels.

2. A trolley for cranes having load engaging means supported thereon and in at least one horizontal direction having a substantially rigid connection thereto whereby horizontal forces on said load engaging means in said direction are transmitted to said trolley, said trolley comprising frame means, wheel casing means carried by said frame means, wheels connected to said wheel casing means for movement on supporting rail means in a horizontal plane thereon, at least one of said wheel casing means and at least one of said Wheels being displaceable said time vertically relative to said frame means, first abutments carried by said frame means, second abutments carried by said displaceable wheel casing means, second abutments cooperating with one another to prevent the frame means from sinking appreciably relative to said wheels from the relative normal position of said frame means but permitting said frame means to rise with respect to at least part of the wheels when said horizontal forces become great enough to separate said abutments, damping means positioned between the wheel casing means and the frame means to damp downward movement of the frame means relative to the wheels, and spring means connected between said frame means and the wheel casing means to urge the wheels connected thereto resiliently downwardly relative to said frame means, said spring means being pre-stressed between said frame means and said wheel casing means.

3. A trolley for cranes having load engaging means supported thereon and inat least one horizontal direction having a substantially rigid connection thereto where by horizontal forces on said load engaging means in said direction are transmitted to said trolley, said trolley comprising frame means, wheel casing means carried by said frame mean-s, wheels connected to said wheel casing means for movement on supporting rail means in a horizontal plane thereon, at least one of said wheel casing means and at least one of said wheels being displaceable vertically relative to said frame means, first abutments carried by said frame means, second abutments carried by said displaceable wheel casing means, said first and second abutments cooperating with one another to prevent the frame means from sinking appreciably relative to said wheels from the relative normal position of said frame means but permitting said frame means to rise with respect to at least part of the wheels when said horizontal forces become great enough to separate said abutments, and combined spring and hydraulic damping means positioned between the wheel casing means and the frame means to damp downward movement of the frame means relative ot the wheels and to urge the wheels resilientlydownwardly relative to said frame means.

4. A trolley for cranes having load engaging means supported thereon and in at least one horizontal direction having a substantially rigid connection thereto whereby horizontal forces on said load engaging means in said direction are transmitted to said trolley, said trolley comprising frame means, wheel casing means carried by said frame means, wheels connected to said wheel casing means for movement on supporting rail means in a horizontal plane thereon, at least one of said wheel casing means and at least one of said wheels being displaceable vertically relative to said frame means, first abutments carried by said frame means, second abutments carried by said displaceable wheel casing means, said first and second abutments cooperating with one another to prevent the frame means from sinking appreciably relative to said wheels from the relative normal frame means to rise with re-' said first and,

position of said frame means but permitting said frame means to rise with respect to at least part of the wheels when said horizontal forces become great enough to separate said abutments, hydraulic damping means positioned between the wheel casing means and the frame means to damp downward movement of the frame means relative to the wheels, said damping means for each of said wheel casing means having a common reservoir for the hydraulic fluid and a cylinder for each wheel casing means connected to said reservoir by means of a duct, each duct having a check valve therein to permit liquid to flow therethrough with slight resistance upon movement of the frame means upwardly with respect to any corresponding wheel, but to resist the flow of fluid therethrough upon the movement of said frame means in the opposite direction.

5. A trolley for cranes having load engaging means supported thereon and in at least one horizontal direction having a substantially rigid connection thereto whereby horizontal forces on said load engaging means in said direction are transmitted to said trolley, said trolley comprising frame means, wheel casing means carried by said frame means, wheels connected to said wheel casing means for movement on supporting rail means in a horizontal plane thereon, at least one of said wheel casing means and at least one of said wheels being displaceable vertically relative to said frame means, first abutments carried by said frame means, second abutments carried by said displaceable wheel casing means, said first and second abutments cooperating with one another to prevent the frame means from sinking appreciably relative to said wheels from the relative normal position of said frame means but permitting said frame means to rise with respect to at least part of the wheels when said horizontal forces become great enough to separate said abutments, and combined spring and hydraulic damping means positioned between the wheel casing means and the frame means to damp downward movement of the frame means relative to the wheels and to urge the wheels resiliently downwardly relative to said frame means, said damping means for each of said wheel casing means having a common reservoir for the hydraulic fluid and a cylinder for each wheel casing means connected to said reservoir by means of a duct, each duct having a check valve therein to permit liquid to flow therethrough with slight resistance upon movement of the frame means upwardly with respect to any corresponding wheel, but to resist the flow of fluid therethrough upon the movement of said frame means in the opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS 546,774 Cliif Sept. 24, 1895 628,832 Morgan et al. July 11, 1899 670,317 Friedlaender Mar. 19, 1901 821,359 Haeberlein May 22, 1906 1,222,588 Allfree Apr. 17, 1917 1,287,336 Kendall Dec. 10, 1918 1,761,747 Rosin et al. June 3, 1930 2,097,966 Edmunds Nov. 2, 1937 2,365,819 Herrick et al. Dec. 26, 1944

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