GB2222572A

GB2222572A - Counterloading arrangement for jib cranes

Info

Publication number: GB2222572A
Application number: GB8918357A
Authority: GB
Inventors: Horst Bendix
Original assignee: MAN Takraf Fordertechnik GmbH
Current assignee: Takraf GmbH
Priority date: 1988-08-25
Filing date: 1989-08-11
Publication date: 1990-03-14
Also published as: GB8918357D0; DE3915771A1; DD275036A1

Description

1 Counter-loading arrangement for jib cranes r) 222-2572 The invention can

be applied to rail-mounted jib cranes and also other mobile jib cranes in which in operation thereof it is important to ensure that the crane stands in a stable condition and in A, transportation thereof, in order to ensure travelling safety, it is important to observe certain axle loadings.

A counter-loading arrangement has been proposed in which fixed counterloads are arranged on the rotatable upper portion of the crane and a movable counterload is arranged on a pivotable counterload arm. In that arrangement the pivotable counterload am is mounted on the rotary connection of the jib crane or is coupled to the rotary connection. In the operating position of the jib crane the counterload arm is pivoted in opposite relationship to the jib under the fixed counterload and thereby ensures a higher level of 'stability. In contrast the counterload am with the movable counterload is pivoted in the direction of the jib in the transportation position of the jib crane in order to observe certain axle loadings. Supports are provided in the bridge frame, in the transportation position, for transmitting forces to the bogies.

A disadvantage in that construction is the large movable counterload which is required to provide for axle loading compensation, and the long counterload arm which is required by virtue of its being mounted on the centre of rotation and by virtue of the mounting of the movable counterload in the operating position beneath the fixed counterload. That has a disadvantageous effect on the length of the 2 lower portion of the crane and thus the overhead load clearance. Other aspects which are disadvantageous are the high level of expenditure as a result of the counterload arm being mounted on the rotary connection and the limited usefulness for cranes with a high load carrying capacity, as a result of a single movable counterload.

In addition, DD-WP 224 Oll discloses a construction for caTpensating for axle loadings, in which ballast weights;R arranged displaceably in the free spaces in the longitudinal bearers of the bottom portion of the crane. Movement is produced by means of a toothed rack. A disadvantage of that arrangement is that the ballast weights only act as central ballast and have only an _Jmoterial influence on improvement in stability of the crane in the standing condition. The use of that construction is also limited to small jib cranes.

An aim of the invention is to Provide a counterloading arrangement for a jib crane, which improves the crane parameters, stability of the crane in the operating condition and travel qualities, including in relation to heavy jib cranes.

Ways were sought of developing a counterloading arrangement which decreases the length of the lower portion 'of the crane in the track direction, to ensure that there is a high degree of freedom in respect of load for use of the crane, which does not exceed the profile limit, which only slightly limits constructional freedom an the upper portion of the crane, and which reduces the length and the cross---section of the counterload arm which carries the movable counterload. Ways were 1 1 3 also sc ighl of providing that the construction can be used for different jib cranes.

According to the invention, counterloads are arranqed fixedly on the upper portion of the crane and a movable counterload is arranqed on a pivotable counterload arm. Upon pivotal movement of the counterload arm, the movable counterload is turned from the operating position into the travel posiLlon or vice-versa simultaneously and in the same direction about the connecting joint with the counierload arm. The point of rotary movement of the counLerload arm lies on the transverse axis of the centre of rotation of the upper portion of the crane or outside same.

In the preferred arrangement, due to the rotary movement of the movable counLerload about the connecting joint with the counterload arm, the joint faces at a right angle to the lonqltudinal axis of the jib crane in an outward direction both in the operating position in the direction of the rails and also in the travel position. A counterload arm with a respective mobile counterload may be arranged at each longitudinal side of the jib crane. The pivotal movement of the counterload arms and the rotary movement of the movable counterloads may be produced by mechanical, hydraulic, pneumatic or electrical means and a per se known motor drive may be arranged as the actuating means for the pivotal movement of the counLerload arm. The rotary movement of the movable counterload may be produced by means of a chain drive (not described in greater detail herein).

As a further alternative form, the actuating means for the rotary movement of the movable counterload may be in the form of a multi-link chain.

Support means can be provided for transmitting the weiqht of the movable counLerload to the lower portion of the crane.

An embodiment of the invention is described below in areater detail with reference to the drawings in which:

Figure 1 is a diagrammatic plan view of an arranqement accordinq to the invention, and Figure 2 is a diagrammatic parL-section on line A-A of Fiqure 1 showing the drive.

4 Referring to Figure 1, the counterloading arrangement for a j ib crane 1 comprises counterloads 3 which are fixedly arranged on the upper portion 2 of the crane and able counterloads 4 which are respectively arranged on pivotable counterload arms 5 which in the travel position are pivoted in the direction of the jib and in the operating position are pivoted oppositely in the direction of the rails.

The movable counterload 4 is rotatably secured to a connecting joint 6. The movable counterload 4 rotates about the connecting joint 6 simultaneously with and in the same direction as the pivotal movement of the counterload arm 5 so that the movable counterload 4 is arranged with its longitudinal axis parallel to the longitudinal axis of the jib crane 1, both in the operating position, in the track direction of the jib crane 1, and also in the travel position. In that connection, the connecting joint 6 faces outwardly from the longitudinal axis of the jib crane 1, in both positions of the movable counterload 4. That gives the advantages that the constructional freedom on the upper portion of the crane is not restricted, stability is guaranteed in all alternative forms of operation, and axle load compensation is made possible in the travel position. As shown in Figure 2 the pivotal movement of the counterload arm 5 is produced by a vertically disposed transmission motor unit 7 by way of a gear transmission. The point at which the motor unit 7 is arranged on the upper portion 2 of the crane is so selected as to provide for maximum compensation in respect of the axle loads and maximum standing mement. As shown in Figure 2 chain wheels 9 are arranged at the motor unit 7 and at the shaft of t;e connecting joint 6 of the movable counterload 4 with the counterload arm 5. In that way the rotary movement of the movable counterload 4 is produced simultaneously with the pivotal movement of the counterload arm 5, by way of an endless chain 10. The transmission ratio in respect of the gear transmission 8 and the chain wheels 9 are such that the counterload arm 5 covers a distance of 1800 from the operating position in the direction of the tracks into the travel position and over that distance the movable counterload 4 is turned through 3600. A counterload arm 5 with a respective movable counterload 4 is arranged on each side of the jib crane 1. That has an advzntageous effect both on the stability of the jib crane 1 in the standing condition, axle load compensation, and the dimensioning of the counterload arms 5. A further advantage is that the arrangement according to the invention-can also be used for heavy jib cranes.

1 h

Claims

1. A counterloading arrangement for jib cranes, comprising counterloads which are fixedly arranged on the upper portion of the crane and a movable counterload which is arranged on a pivotably mounted counterload arm, wherein the movable counterload rotates about a connecting joint with respect to the counterload arm simultaneously with and in the same direction as the pivotal movement of the counterload arm from the operating position into the travel position or vice-versa.

2. A counterloading arrangement according to claim 1 wherein the connecting joint faces outwardly from the longitudinal axis of the jib crane both in the operating position and also in the travel position of the movable counterload.

3. A counterloading arrangement according to claim 1 or- claim 2 wherein the movable counterload ' is arranged with its longitudinal axis parallel to the longitudinal axis of the j ib crane both in the operating and in the travel position.

4. A counterloading arrangement according to any of claims 1 ta 3 whereir there;R provided two pivotable counterload arms each with a respective rotatable movable counterload 5. A counterloading arrangement according to any precedinc, mechanical, hydraulic, pneumatic or electrical claim wherein 7 actuating means are provided for producing the pivotable movement of the counterload armg and the rotary movement of the movable counterloads.

6. A counterloading arrangement according to any preceding claim, wherein support means are provided for transmitting the weight of the movable counterload to the lower portion of the crane.

7. A counterloading arrangement for jib"cranes, substantially as described with reference to the drawings.

8. A jib crane including an arrangement according to any preceding claim.

1.

1 1 PUblIAL110(11990 at The [email protected]&te House. 8#17 1 F-I&IIHolburn, London WCIA4TP Airtzier copies m&y be obtaLnedfrorn The PatentOMos. Sxiss Branch. St Mary Cray, Orpinawn, Ksnl.'8RS 3RD. Printed by Multiplex tec=ques ltd. St Mary Cray. Kent. Con. 187