GB2193185A

GB2193185A - Overhead travelling crane

Info

Publication number: GB2193185A
Application number: GB08618686A
Authority: GB
Inventors: Anatoly Vasilievich Trushin; Vladimir Arkadievi Dobrovensky; Arkady Semenovich Malkin; Evgeny Ivanovich Shevchenko; Vladimir Georgievich Gutsol; Alexei Danilovich Petrov; Jury Georgievich Buryak; Anatoly Ivanovich Zakharov
Original assignee: Dn Metall Inst
Current assignee: Dn Metall Inst
Priority date: 1986-07-31
Filing date: 1986-07-31
Publication date: 1988-02-03
Also published as: GB8618686D0; FR2602500B1; FR2602500A1; GB2193185B; DE3627983A1

Abstract

The trolley of an overhead travelling crane has two main girders (2) rigidly connected, through one pair of their ends, to one of the end girders (1), while the other ends of the girders are traversably connected to the other end girder (4) and are rigidly interconnected through a cross girder (3). The transversable end girder (4) carries an arm (5) with a roller (6) engaged with guides (9) on the cross-girder (3). Rollers (7) on the end girder (4) engage the main girders. <IMAGE>

Description

SPECIFICATION Overhead travelling crane This invention relates generally to materials handling machinery and more specifically it concerns overhead travelling cranes operated at most diverse enterprises and especially at open trestles.

The present invention can find application both for reconstruction of the cranes now in action and for manufacture of new cranes.

At present there are operated mostly overhead travelling cranes featuring rigid interconnection of the end and main (longitudinal) girders. As a result of inaccurately installed crane travelling wheels their translational motion is accompanied by turning and slipping over the crane runways. It is the side forces arising within the contact zone of the wheel flanges with the rail head that are instrumental in compensating for said crane travelling inaccuracies. As a result, however, an intense wear on both the wheel flanges and rail heads occurs, as well as premature failure of the crane metallic structures.Such a wear on the flanges of the crane travelling wheels and failure of the crane metallic structures is liable to occur at extremely high rate at open trestles or load handling ramps, wherein constant interaxial spacing of the crane runway rails (track width) is too difficult to maintain in the course of crane operation.

Known in the present state of the art are also overhead travelling cranes having movably interconnected end girders. When the wheel of such a crane rides over the rail head, the end girders are mutually displaced, the lateral loads applied being insignificant. This in turn adds to the service life of both the cranes and their runways.

Known heretofore is one prior-art overhead travelling crane whose metallic construction consists of two L-shaped members, each incorporating an end apd a main girder, both being interconnected to provide mutually movable interconnection of said L-shaped members. Practical experience gained in operating such cranes has demonstrated that provision of a rigid and movable connection of the same end girder with the main girders results in different-value deformation of the main girders in a horizontal plane, which might lead to derailing of the crane trolley from the runways as a result of an opposite traversing of the main girders alongside with the trolley rails laid thereon.

One more overhead travelling crane which is the closest to the one being disclosed in this invention as to its technical essence and results attained, comprises two main girders of which one pair of ends is rigidly connected to one of the end girders, while the other end girder is movably connected to the free end of the main girders through the agency of a rotary frame provided with two arms. The arms carry rollers and are directed inwards the main girders. The crane bridge incorporating the two main girders along which the crane trolley travels, is in fact suspended from the arms. However, when the roller-carrying arms are displaced with respect to the main girders accompanied by simultaneous deformation of the main girders from vertically applied loads, the arm-carried rollers are liable to seize or jam in the guideways provided inside the main girders.Besides, the mere fact that the crane bridge is suspended from the arms across the span is fraught with a danger.

It is a general object of the present invention to eliminate the disadvantages mentioned above.

It is a specific object of the invention to provide an overhead travelling crane having such a construction that would incorporate movable end girders so as to ensure reduced side loads on the flanges of the crane runway rails and would render crane operation safe: The aforesaid object is accomplished due to the fact that in an overhead travelling crane incorporating two main girders which are rigidly connected, through one pour of their ends, to one of the end girders, while the other ends of said girders are movably connected to the other end girder and are rigidly interconnected through a cross girder, according to the invention, located on the traversable end girder is a means for its fixing in position, said means being interposed between the main girders and arranged lengthwise their longitudinal axes.

According to one of the embodiments of the invention, the means fQr fixing the traversable girder in position is made as at least one cantilevered arm whose free end carries a roller featuring a horizontal axis of rotation and being adapted to contact guideways provided on the cross girder.

According to another embodiment of the invention, the means for fixing the traversable girder in position is made as at least one cantilevered arm whose free end carries a roller featuring a horizontal axis of rotation and being adapted to contact guideways provided on the main girders.

Such a constructional arrangement of the overhead travelling crane of the invention provides for its higher durability, longer life and makes it safer in operation.

The essence of the present invention resides in that the crane bridge is in effect a closed truss established by the two main girders rigidly interconnected through one of the end girders and the cross girder The crane bridge incorporating one of the end girders, is movably connected to the other end girder through rolls. To ensure against turning of the traversabiw end girder with respect to the rail, the girder is fixed in position relative to the main girders using a means made as a canti levered arm carrying a roller. Since the armmounted roller is in fact the third point of support of the end girder, the arm is arranged square with the axis of the rail that supports two travelling wheels of said girder and is directed lengthwise the longitudinal axes of the- main girders.Interposing of the arm between the main girders is accounted for by the fact that located outside the girders are attendance platforms bearing the crane control devices and equipment.

Provision of an overhead travelling crane featuring the herein-proposed constructional arrangement of fixing the traversable end girder in position makes it possible to attain longer service life of the crane and to prevent the travelling wheels of the crane trolley against derailing, thus ensuring safe crane operation.

The invention can be successfully utilized in the now-operated rigid-construction overhead travelling cranes by disconnecting one of the end girders from the main girders and appropriately fixing said end girder with respect to the main girders.

Given below is a specific embodiment of the invention which is illustrated by the accompanying drawings, wherein: FIG. 1 a general diagrammatic view of an overhead travelling crane; FIG. 2 is a plan view of FIG. 1 showing the guideways provided on the cross girder; and FIG. 3 is a view of FIG. 2 illustrating the guideways provided on the main girders.

The overhead travelling crane (FIG. 1) according to the invention comprises an end girder 1 rigidly interconnecting one pair of the ends of main girders 2, and a cross girder 3 (FIG. 2) rigidly interconnecting the other ends of the main girders 2.

There is also provided an end girder 4 on which the ends of the main girders 2 rest movably, thus rendering the end girders 1 and 4 mutually movable. Located on the traversa ble end girder 4 is a means for its fixing in position, said means being interposed between the main girders 2 lengthwise their longitudinal axes. The aforesaid means may be made as an arm 5 cantilevered to the girder 4 and carrying at its free end a roller 6 featuring a horizontal axis of rotation.

Movabie interconnection of the main girders 2 with the end girder 4 is attained through the use of rolls 7 located inside the end girder and adapted to contact a bearing surface 8 of the main girders 2.

The arm 5 of the end girder 4 is arranged along the crane longitudinal axis so that the roller of the arm 5 is in contact with guideways 9 provided on the cross girder.

FIG. 3 illustrates a plan view of the overhead travelling crane of the invention. The movable end girder is fixed in position by the two arms 5 carrying rollers when the arm are arranged lengthwise the longitudinal axes of the main girders and are spaced different distances apart from them. The guideways 9 are held in place with the aid of supports 10 directly to the main girders. The supports 10 may be in effect plain steel plates.

This makes it possible to position the cross girder 3 above the traversable end girder, thereby extending the crane trolley travel.

The overhead travelling crane of the invention operates as follows.

When the flange of any travelling wheels of the end girder 1 runs against the rail head, a side force arising in the zone of contact of the wheel flange with the rail, urges to displace the end girder 1 alongside with the main girders 2 and the cross girder 3 with respect to the traversable end girder 4. Upon riding the flange of the travelling wheel of the traversable end girder 4 over the rail head the similar displacement of said end girder 4 occurs with respect to the main girders 2 and the end girder 1 and the cross girder 3 connected to the end girder 4, this displacement being effected due to the fact that the bearing surface 8 of the main girders 2 rolls over the rolls 7 and the roller 6 connected to the traversable end girder 4 through the arm 5, runs on the guideways 9.FIG. 2 illustrates the guideways 9 provided on the cross girder 3 rigidly interconnecting the free ends of the main girders 2. Such being the case, the arm 5 of the traversable end girder is arranged lengthwise the longitudinal axis of crane symmetry.

FIG. 3 illustrates the guideways 9 installed on the supports 10 which are fastened immediately on the main girders 2. In such a case the traversable end girder 4 is provided with the two cantilevered c arms 5 located inside the main girders 2 and arranged lengthwise their longitudinal axes. The number of the arms in this case is so selected as to eliminate the thus-created bending moments by uniform load distribution.

In both of the aforementioned cases the lateral force arising on the wheel flange depends on the force of resistance to the rolling motion performed by the rolls 7 and the roller 6, which force is but insignificant in value as compared with forces required to prevent the entire crane against being turned with respect to its runaways.

Thus, the effect of practical application of the overhead travelling crane of the present invention as compared with the heretoforeknown ones, resides in reduced loads on the flanges of the crane runway rails, as well as in a possibility of crane travel along curved runway rails. Furthermore, safe operation of the crane trolley and of the crane as a whole is also provided.

As a result of reduced loads on the wheel flanges the crane metallic structure in a horizontal plane is decreased and its specific metal consumption is reduced accordingly.

Claims

1. An overhead travelling crane, comprising two main girders which are rigidly connected, through one pair of their ends, to one of the end girders, while the other ends of the girders are movably connected to the other end girder, and are rigidly interconnected through a cross girder and a means for the traversable end girder to fix in position is located on the same girder, the means being interposed between the main girders and arranged lengthwise their longitudinal axes.

2. An overhead travelling crane as claimed in Claim 1, wherein the means for fixing the traversable girder in position is made as at least one cantilevered arm whose free end carries a roller featuring a horizontal axis of rotation and being adapted to contact guideways provided on the cross girder.

3. An overhead travelling crane as claimed in Claim 1, wherein the means for fixing the traversable girder in position is made, as at least one cantilevered arm whose free end carries a roller featuring a horizontal axis of rotation and being adapted to contact guideways provided on the main girders.

4. An overhead travelling crane substantially as herein described with reference to and as illustrated in the accompanying drawings.