Turns large loads by hoisting

Summary

The invention features a turning apparatus using a hoist system and includes a winding (hoist) electric motor, a decelerator to work on the winding motor, a drum for wire rope (cable), a sheave connected to the drum by wire rope, a hoist section (with hook section connected to the sheave by wire rope) and the turning apparatus itself hung on the hook section to turn a heavy object.

The hoist, in fact, includes a pair of hoists installed on a girder, and working together so that the weight of a heavy object hung on the hoists can be halved between the two hoists, thus avoiding overloading.

Improving

The patent points out that conventional turning hoist apparatus for heavy objects has a complicated structure and/or limited utility. One such design was filed as Korean Utility Model Application Number 2003-0036791 by Korea Gorbel. This has an upper fixing section to attach under the hoist, a decelerator and brake formed on one side of a central friction pulley, and thence connected to a drive motor on the other side. The heavy object is turned by friction force of the pulley and means of connection (wire rope etc). However, the friction force decreases rapidly with weight perhaps causing slippage.

Also, in this design, as the motor and friction pulley work together to rotate the heavy object, the weight is concentrated on the friction pulley and the connection portion when the motor rotates. Extended use may abrade the rope. The friction drum is extended to accommodate the size of the heavy object and consequently the object’s weight is increasingly concentrated on the friction drum. Thus the strength of the drum has to be increased with the weight of the object.

In operating this existing apparatus the operator controls the turning operation based only on personal observation and motor power. An operator mistake may overload the motor, shortening its service life, and/or creating a dangerous situation causing the load object to escape. Neither can the operator accurately control the rotating speed and turning angle without precise determination. It may not be possible to operate the apparatus for a heavy object of high volume.

The apparatus has to be disassembled after use so that the hoist can lift and transport the load as normal, but this causes inconvenience and extended working time.

Objectives

Thus the new development has the objectives of overcoming these drawbacks, based on the use of two hoists installed on the upper side of a girder, without the use of a friction drum. The heavy object is connected to the hook from the hoists by a sling in order to divide the load between the two hoists, and object turning carried out without any overload.

The new design provides a sheave frame with an upper sheave rotationally fixed the frame and pivotally connected to the bottom portion of a support bracket with a pin. This allows the sheave frame to be moved to an angle corresponding to the size of the heavy object with adjustment. The length of the wire rope should be extendible so that any turning job can be performed without limitation on the size of the object. With the sling connected to a hook, the sheave frame should be capable of pivoting to an angle corresponding to the size of the heavy object without the wire rope escaping from the sheave.

The pair of hoists can operate without a separate turning apparatus so that normal lifting and transporting work can be carried out without any separate installation or disassembling work.

Lastly there can be no slippage to ensure safe work and no additional maintenance.

Best mode

Referring to the accompanying figures (selected from 15 published), the preferred embodiment of the invention is described.

In Fig 1 the hoist section (10) is composed of a bracket section (11) for fixing to the upper portion of a girder, a transverse-travel driver section (12) fixed at the bracket section, a driver section (13) for driving the turning apparatus (also fixed at the bracket section), a control section (14) to control the driver section (also fixed at the bracket), an upper sheave section (15) pivotally fixed at the bottom portion of the bracket section, according to the size of the heavy object load, and a hook section (Fig 2 – 16) for lifting the heavy object.

The transverse-travel driver section includes a support-transverse travel wheel (121) configured to be running on two lengths of girders (100). The driver-transversal travel wheel (123) is extended by a shaft (122) across the pair of lateral fixing brackets and is driven by a transversal-travel motor (124) through connecting gearing or drive belt or chain. Thus the turning apparatus can be moved by this assembly along the girders.

The driver section includes a winding motor (131) fixed to the rear of the transversal-travel driver section with a shaft connection through the lateral fixing bracket. On the opposite side to the traversal-travel motor, the wire drum (133) is situated at the rear of the of the support bracket.

The two wire drums have a pair of wire ropes (132) spaced apart from each other. The drums are bolt-fixed to the lateral fixing brackets with the shafts protruding through. A decelerator (134) is connected to each wire drum, passing through the lateral fixing bracket and the shaft of the winding motor. It transfers the rotation of the winding motor to the wire drum at a reducing ratio, a supplied by a selective gearbox, chain or belt drive. A brake (135) also controls the decelerator, being inserted in either side of the decelerator body and fixed with a bolted connector.

The control section is configured to control the travel and stopping of the turning apparatus, winding operation, and pair of hoist sections. It is fixed to outside of the driver section fixing bracket, and thus connected to the shaft of the wire drum. The driver section includes a control panel to execute the operations from the operator section. The latter is connected with the control panel by electric cable and can be operated from the floor of the workplace by pendant or wireless, or from an operating cabin under the supporting girders.

The upper sheave section is fixed to the centre of the bottom of the main support bracket with a fixing plate. It includes an upper sheave (152) connected with a wire rope wound around the wire drum, and an upper sheave cover (153) where the sheave is fixed and rotates. The disc of the upper sheave cover is formed integrally with fixing plates so that the upper sheave can be protected at one bottom side of a hollow rectangular frame. One or more pairs of upper sheaves can be rotated with the disc centre of the sheave cover using a shaft.

The end of the wire rope unwound from the wire drum is fixed to the outside of the upper sheave cover at the sheave. So, when the upper sheave section is pivoted the wire rope is also pivoted and wound round the upper sheave, thus preventing its release. Each upper sheave cover is connected between a pair of fixing plates with a pivot pin, also preventing the wire rope from escaping.

The hook section includes a lower sheave (161) in one pair or more connected to the wire rope, and has a cover (163) to which the hook (161).

The two hoist sections are identical as above in mirror image with connection of the support-transversal travel wheel facing each other in pairs. The connection is either by an electromagnet (using an applied electric current) or suitable bracket (113). The connection bracket has a D-shape with its bottom portion opened, and constructed so as to be inserted from the upper portion of the support-transversal travel wheel and connected by a bolt-and-nut or pin method. An alternative means of connection (Fig 2 – 113) at this point uses a latching pin, a pair of lateral plates and a pivot pin.

The patent describes the detailed construction of this means of connection, not included here.

The hoist section (Fig 3 – 10) may be constructed so that the rectangular frame supporting the facing support-transversal wheel is constructed integrally, so that the pair of hoist sections can be used without having to be disassembled.

Operation

As shown in Figs 3 and 4, a means of turning (300), such as a flat belt, of rigidity and toughness, is inserted into the bottom part of the heavy object to be handled and supports it. At first the belt, for example, is wound around the heavy object in two rows so that the transverse and vertical portions of the heavy object are symmetrical and balanced. The means of turning is also connected to both sides of the heavy object, with the end portions exposed. Thus the lifting side of the belt becomes shorter and the descending side therefore becomes longer. Each end portion is firmly fixed using a sling (Fig 3 – 400).

The turning belt is divided so that two of them can be used as one pair. The end portion is in contact with the upper and lower edges at one side of the heavy object, and a circular hook can be used to connect the end portions. Thus the turning belt will not be moved or escape from its initial position due to any wobbling when the heavy object is turned.

Once the turning belt and sling are in position the pair of hoists can be initiated by the installed means operation (pendant cable control, wireless or from an operator’s cabin), and the hoist sections positioned above the centre of the heavy object.

Once the desired orientation to be achieved by turning of the heavy object is determined, the operator section is used to rotate each winding motor individually, and pair of hoist sections, so that the hook can be connected to both slings, with the hook section placed at the lower side, and with the extended lengths of wire rope being different.

If the installation width is less than the width of the heavy object at this point, the upper sheave section is pivoted to prevent the wire rope connected to the upper sheave from escaping.

Thus the winding motor is rotated to place the hook section so that the wire rope becomes longer at the hook section of the heavy object lifting side, and shorter at the hook on the opposite side. This completes the connection of the sling in preparation for turning the heavy object.

The winding motor at the hook section of the longer length of wire rope is rotated to be pulled, and the winding motor at the hook section of the shorter length of wire rope rotated to lengthen the wire rope. The length of the wire rope is adjusted to position the hook section centrally between the hoist section and the heavy object being turned.

As shown in Fig 4, by operating the relevant winding motors in the hoist sections simultaneously in equal but opposite directions, one side of the heavy object is lifted and the other side descends. At the middle of the distance between the hoist section and the heavy object the lengths of wire rope on both sides are identical and heavy object becomes upright.

Application

In use of the turning apparatus there is no restrictions on the size or length of the heavy object being handled. Since the load is halved between the pair of hoist sections, the system can be applied to objects weighing in excess of 150t.

The patent claims that all the objectives (as above) in improving previous designs have been achieved with the developments covered by the patent.

About the patent

This article is an edited version of WIPO international patent publication number WO/2007/086628, published on August 2 2007, and based on an application filed in Korea on January 27 2006. The inventor is Duck-Rae Cho of Buncheon, Kyunggi-do, and the applicant is Korea Gorbel Co Ltd. of Incheon City, Republic of Korea.

Disclaimer

This article is an edited version of the patent and may omit legally or technically important text. To see the full patent go to www.hoistmagazine.com/patents

Marketing

The applicant, and KG Cranes, are major manufacturers and suppliers of hoist and crane systems in Korea, and part of the Gorbel group of the USA. Individual hoists have capacities up to 400t, so that the development above can be used for objects of up to 800t in a single arrangement. For more information contact KG Inc., tel: +82-32-583-6671, fax: +82-32-583-6674, email: wills@kgcrane.com or Gorbel Inc., tel: +1 585 924 6262, fax: +1 585 924 6273, email: csr@gorbel.com.

Fig 2 – Side view of the turning apparatus and hoist of the invention Fig 2 Fig 3 – Elevation of the turning apparatus when prepared for turning a heavy object
Fig 3 Fig 1 – Bottom view of the turning apparatus and hoist Fig 1 Fig 4 – Side view of the turning apparatus in operation with the heavy object turned through 45 degrees Fig 4