US3842986A

US3842986A - Device for accurately positioning a body suspended from cables

Info

Publication number: US3842986A
Application number: US00221361*A
Authority: US
Inventors: L Hupkes
Original assignee: WERF CONRAD AND STORK
Current assignee: CONRAD-STORK BEHEER BV; WERF CONRAD AND STORK
Priority date: 1971-01-29
Filing date: 1972-01-27
Publication date: 1974-10-22
Anticipated expiration: 1991-10-22
Also published as: BE778379A; AU3814472A; FR2124940A7; GB1375756A; NL7101224A; DE2203245A1

Abstract

A body is suspended from a trolley solely by hoisting cables or by a combination of hoisting cables and positioning wires. In the case when only hoisting cables are employed, they pass on drums joined together and so operated to raise and lower the load, the hoisting cables passing on sheaves and being connected to the trolley by support members which are pivotable to compensate for load differences in the cables, the sheaves also being pivotable on the trolley to compensate for elongation differences in the cable. In the case when positioning cables are utilized, the latter are connected to a driving drum over pivotable sheaves to compensate for elongation differences in the cables, the ends of the hoisting cables being connected to the trolley by displaceable support members which compensate for load differences in the hoisting cables.

Description

United States Patent [191 Hupkes DEVICE FOR ACCURATELY POSITIONING A BODY SUSPENDED FROM CABLES [75] Inventor: Leonard Hupkes, Heemstede,

Netherlands [73] Assignee: Werf Conrad & Stork lHiisch N.V. [22] Filed: Jan. 27, 1972 [21] Appl. No.: 221,361

[30] Foreign Application Priority Data 212/83, 11; 254/144, 173; 214/14.15; 244/81 SF; 294/81 SF, 67 R [56] References Cited UNITED STATES PATENTS 3,161,309 12/1964 Baudhuin et al. 294/81 SF 3,179,259 4/1965 McLean 212/126 3,273,860 9/1966 Weisenbach 254/173 3,510,107 5/1970 Fidler 254/173 FOREIGN PATENTS OR APPLICATIONS 742,094 9/1966 Canada 254/173 [4.51 Oct. 22, 1974 Primary Examiner-Evon C. Blunk Assistant ExaminerHadd Lane Attorney, Agent, or Firm-Eric l-l. Waters 5 7] ABSTRACT A body is suspended from a trolley solely by hoisting cables or by a combination of hoisting cables and positioning wires. in the case when only hoisting cables are employed, they pass on drums joined together and so operated to raise and lower the load, the hoisting cables passing on sheaves and being connected to the trolley by support members which are pivotable to compensate for load differences in the cables, the sheaves also being pivotable on the trolley to compensate for elongation differences in the cable. In the case when positioning cables are utilized, the latter are connected to a driving drum over pivotable sheaves to compensate for elongation differences in the cables,

the ends of the hoisting cables being connected to the 2 Claims, 5 Drawing Figures DEVICE FOR ACCURATELY POSITIONING A BODY SUSPENDED FROM CABLES BACKGROUND OF THE INVENTION a. Field of the Invention The present invention relates to a device for accurately positioning a body suspended via an engaging means from one or more cables of a hoisting device in which at least two cables or wires, which are in communication with the body or the engaging means, are guided each at an angle to the vertical, and not parallel to each other, to a drum which may be driven. b. Prior Art A device of this type is disclosed in Applicants earlier Application Ser. No. 158,539 filed Aug. 3, 1974. In said device, special positioning wires are passed to drums which may be driven, said drums being coupled in such a manner that a rotation of the drums relative to each other will effect a change in the driving moment of one of the drums. It has appeared that this device permits a displacement of the container due to elongation in the positioning cables, which, in practice, may become excessive.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a device of the aforementioned type which does not have the disadvantage associated therewith. r

In accordance with the invention, a device is provided for accurately positioning a body suspended from cables of a hoisting device, said device being characterized' in that means are provided to prevent a change in the positions of the drums for the wires or cables relative to each other, at least in the sense that one drum will unwind relative to the other drum, irrespective of the amount of stress in the wires, and further means are provided to compensate for the differences in elongation in the wires and/or the cables. The inclined wires or cables may consist of special positioning wires or they may be formed by the hoisting cables, in the first case one or more separate drums for the positioning wires are provided.

The means for preventing a change in the positions of the drums relative to each other, consists preferably of mechanical coupling means for the drums or of means for uniting the drums as one single drum around which the two wires are passed in the same sense.

The means for preventing a change of the positions of the drums relative to each other may also consist of an analog or digital control of the driving means of the drums.

In a device with separate positioning wires, the means for compensating for the differences in elongation of the wires preferably comprises movably mounted sheaves, over which the positioning wires are passed to the drums and a device which can transform a difference between the stresses in the wires into such a relative movement of said guiding sheaves that the difference in elongation will be compensated.

In the embodiment in which the driving means of the drums of the wires or cables are controlled by analog or digital means, the means for compensating for the differences in elongation of the wires or cables may also consist of means controlling the driving means of the drums so that the drum around which the wire or cable subjected to the greatest stress is passed will wind up relative to the other drum.

If wind forces act on a body suspended from hoisting cables in a device as described above, then it is not possible that a horizontal displacement of the body will occur, inasmuch as the positioning wires or the hoisting cables will prevent such a displacement. In doing so, one of the positioning wires or hoisting cables will be subjected to a higher load and the other wire or cable will be subjected to a lower load, as a consequence of which the wire or cable with the higher load will elongate, however, said elongation will be compensated in one of the ways described above, so that also a horizontal displacement resulting from said elongation is prevented.

Thus, a body suspended by cables of a hoisting device may be accurately positioned as to the position where the body is to be deposited. Accurate positioning, however, requires also that the body will come down in the correct position. With a container this means with its surface absolutely horizontal. This will be the case if the center of gravity of the container lies on the vertical central axis of the container. This is often not the case, so that as a consequence of the unequal loads of the hoisting cable which then occur, the cables will not stretch to the same extent and the container will hang aslant.

In order to prevent this, both in the device with positioning wires and without same, in accordance with the invention, the cables from which the body is suspended are connected with a system for measuring the differ ences in load between said cables, while the points where said cables engage the hoisting device are engaged in movably mounted supports, and a mechanism is present to move said supports in response to the measured differences in load so that the difference in elongation of the cables will be compensated Inasmuch as the elongation of a cable or a wire apart from the load is also dependent from the length of the cable or wire, a device is present in accordance with the invention, which can control the measuring system for measuring the differences in load between the hoisting cables and/or the means for compensating the differences in elongation in the positioning wires in dependency on the length of the cable between the body and the hoisting device.

The invention will now be described in greater detail, with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic side view of a first embodiment of the present invention with separate positioning wires;

FIG. 2 is a schematic view, on enlarged scale, of an alternative embodiment of a means for compensating the differences in elongation in the positioning wires;

FIG. 3 is a perspective view of a second embodiment of the present invention, without separate positioning wires;

FIG. 4 is a perspective view of a means for compensating the differences in elongation in the hoisting cables illustrated in FIG. 3; and

FIG. 5 shows in perspective a means for guiding the hoisting cables illustrated in FIG. 3 by means of a spring.

DETAILED DESCRIPTION Regarding FIG. 1, therein is seen part of a girder 1 of a container bridge, along which a trolley 2 may travel on wheels 3. A hoisting drum 4 is mounted on the trolley, and hoisting cables 5 of the drum extend to sheaves 6 on a lifting frame of a container. The hoisting cables 5 extend around the sheaves 6 and are fixed at supports 8 on the trolley 2. Measuring systems are built in the support 8 to measure the differences in load in the hoisting cables and control a mechanism (not shown) to move the supports 8 in a manner so that the difference in elongation of the hoisting cables will be compensated, whereby the lifting frame 7 and the load 9 suspended therefrom will remain absolutely horizontal. This movement may be continuous or stepwise. It is also possible to adapt the movement of the supports 8 of the hoisting cables 5 to a secondary action, such as an offset position of the center of gravity of the load 9 or a difference in deflection of the girder 1.

Additionally, a drivable drum 10 is mounted on the trolley 2, and positioning wires 11 extend around drum l0 and are guided on sheaves 12 to the lifting frame 7 of the container. The drum 10 is subjected to a suitable constant torque so that the wires 11 will be kept continuously tensioned, both during standstill and during the hoisting and lowering of the load 9. The sheaves 12 are mounted on hinged rods 13 which are connected to each other by a rod 14. Measuring devices 15 are mounted on rod 14 to provide a signal which is transmitted to a control device 16 which can move the rod 14 to the left or to the right. Thus, if, for example, a wind force acts on the right-hand lateral face of the container 9 (as shown in the drawing), the positioning wire 11 at the extreme right will be subjected to a higher load than the positioning wire 11 at the extreme left side. This difference in load will be measured by the measuring systems 15 which control the device 16, as a consequence of which the rod 14 is moved to the right. The result of this movement is that the right-hand guiding sheave 12 will swing to the right, whereby the higher elongation in the right-hand positioning wire 11 will be compensated. The movement of the sheaves 12 may be effected either continuously or in one or more steps; it is also possible to compensate by these movements the secondary actions of the wind force, such as the deflection of the stationary leg and the girder of the container bridge.

Because the elongation in the positioning wires 11 is also dependent on the length of these wires and because the angle of said wires to the vertical changes during hoisting and lowering, the load on the wires 11 not only depends on the wind force on the container 9 but also on the distance between the container 9 and the trolley 2. In order to take this into account, a device (not shown) is provided which regulates the measuring system 15 in conformity with the distance between the It is also possible, as shown in FIG. 2 for each guiding sheave 12 to be adjusted independently. FIG. 2 illustrates only one of the sheaves 12, and the sheave is rotatably secured to the end of one of the arms of a bellcrank lever, 17. The lever 17 is rotatably secured at its center to a frame 18, and the end of lever 17 remote from sheave 12 is connected with one end of a load measuring unit 19. The other end of unit 19 is engaged with a lever 20. The lever 20 is hinged at one end to the frame 18 and is connected at its other end with an adjusting device 21, which in the present embodiment comprises a hydraulic cylinder. When the load measuring unit 19 records a difference in the load in the positioning wires 11, a signal is produced by which the adjusting device 21 is operated in a manner so that the sheave 12 will swing in one direction or the other. If, for example, the load on the positioning wire 11, illustrated in FIG. 2, is higher than in the other positioning wire (not shown), then the adjusting device 21 will push the lever 20 down, as a result of which the bellcrank lever 17 will swing counterclockwise and the sheave 12 will move to the right.

It is, of course, also possible to put the adjusting device into operation, starting from a measured displacement of the lifting frame 7 of the container 9.

A second embodiment of the present invention is illustrated in FIG. 3, in which no separate positioning wires are employed. In FIG. 3, four drums 23 are mounted on a trolley 22, said drums being rigidly coupled to each other. The drums 23 may also be constructed as a single drum. Two hoisting cables 24 extend from each one of the drums 23 via guiding sheaves 25 to sheaves 28 mounted on the lifting frame 27, said lifting frame engaging container 26, said hoisting cables extending further to points of attachment 29 on the trolley 22.

When the center of gravity of the container 26 is centrally located and no horizontal forces act on the container 26, all the hoisting cables have an equal load. If a horizontal force, such as a wind force occurs during the positioning of the container 26 or if the center of gravity is offset, the eight hoisting cables are then subjected to different loads and the container 26 will hang aslant as a consequence of the differences in elongation in the hoisting cables 24 caused by the different loads. In order to compensate these differences in elongation, each point of attachment 29 comprises a load measuring device 30 (as shown in FIG. 4), which measures the rope tension. In response to the differences in force measured by the load measuring devices 30, a signal is produced by which a stepping motor 31 is operated. The stepping motor 31 drives a transmission mechanism located in a casing 32 to cause a lever 33 to be pivoted in one direction or the other. As a consequence thereof, the differences in elongation resulting from the load will be compensated, to prevent the container from tilting and moving horizontally.

It is often desirable that during the travel of the trolley or the bridge, there is a possibility of swaying of the load. To this end, the guiding sheaves 25 are rotatably -mounted on the end of one of the arms of a bell-crank lever 34, as illustrated in FIG. 5. The lever 34 is rotatably supported in its center by a supporting means 35 mounted on the trolley 22. A spring 36 is located between another supporting means (not shown) which is mounted on the trolley and the lever 34, so that the sheaves 25 may move when the load sways and the spring 36 will form a buffer. At the end of its other arm, the bell-crank lever 34 is connected to a hydraulic cylinder 37, whose piston is connected to the frame 38 through a piston rod, the frame 38 being rigidly mounted on the trolley 22. A hydraulic liquid is present on both sides of the piston in the cylinder 37, the liquid being displaced from one side of the piston to the other side via pipes 39 and 40 and an open blocking valve 41 as a consequence of swaying of the lever 34. The pipes 39 and 40 extend to a pump 42, and a valve 43 is mounted in the pipes, the valve 43 being in closed position during the above mentioned operation, If swaying or any eccentric position of the container is to be ruled out during the positioning of the container, the blocking valve 41 is closed and the valve 43 opened, as a result of which the piston in the cylinder 37 is displaced to a terminal position in which the bell-crank lever 34 cannot move.

What is claimed is:

1. Apparatus for suspending a body, comprising a trolley, a single drum means supported on said trolley, at least two pair of cables positively connected to said single drum means and said body and each cable of each pair extending at a substantial angle to the vertical and in non-parallel relation to the other cable of the pair and converging at said body, said drum means being drivable in rotation to cause said cables to raise and lower the body respectively at the locations where the cables are connected to said body, a plurality of pivotal support members mounted on the trolley, an equal plurality of sheaves each being supported on a respective support member for pivoting therewith, one cable passing on each sheave and being connected to the drum means and to the body, means .acting on said pivotal support members to move each of the same and the respective sheaves supported thereby and means controlling the last said means to operate the same and move the plurality of pivotable support members for cancelling any difference in elongation of the cables and thereby obviate any tilting or eccentric movement of the body.

2. A device as claimed in claim 1 wherein said single drum means comprises a plurality of drums, a plurality of pairs of said cables being provided for each drum, and a mechanical coupling means joining said drums together for rotation as a common unit.

S TRIM LIN Patent No. ,986 Dated October 22; 1974 PRINTET- Inventor(s) Leonard Hupkes It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet item 130] "1224/71" should read Signed and sealed this 4th day of February 1.975.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents FORM PO-10SOH0-69) USCOMM-DC 60376-P69 u.s. GOVERNMEN'Y PRINTING OFFICE a n v cm

Claims

1. Apparatus for suspending a body, comprising a trolley, a single drum means supported on said trolley, at least two pair of cables positively connected to said single drum means and said body and each cable of each pair extending at a substantial angle to the vertical and in non-Parallel relation to the other cable of the pair and converging at said body, said drum means being drivable in rotation to cause said cables to raise and lower the body respectively at the locations where the cables are connected to said body, a plurality of pivotal support members mounted on the trolley, an equal plurality of sheaves each being supported on a respective support member for pivoting therewith, one cable passing on each sheave and being connected to the drum means and to the body, means acting on said pivotal support members to move each of the same and the respective sheaves supported thereby and means controlling the last said means to operate the same and move the plurality of pivotable support members for cancelling any difference in elongation of the cables and thereby obviate any tilting or eccentric movement of the body.