Summary
The patent discloses an ergonomic hoist including a lifting assembly riding on a rigid support. A load support assembly is connected to the lift assembly via a lift arm. The device has an operator panel connected to the support assembly via a support arm. The panel is maintained at substantially the same height when the support assembly moves with the load.
Background
The invention of the lifting equipment and method relates to the transferring of loads between different positions for manufacturing purposes. The design is intended for engine transfer but can also be adapted to other heavy objects. The target stations may include conveyors, making the transfer even more challenging, time-consuming and difficult for the operator, even when using the various types of cranes and hoists previously available, especially when depositing the load onto another conveyor.
In particular, internal combustion engines often weigh over 400kg, say the inventors, and may require transfers into a vehicle for installation as well as between assembly stations and conveyors. In manufacturing lines hundreds of engines may need to be transferred from one moving conveyor system to another, with 500 or more movements in a typical shift.
In using existing electric winches, etc. the operator uses a hand-held pushbutton pad whilst standing in one spot, holding the pad in one hand to manipulate the crane over the load object to make a connection using a wire rope, etc. On lifting the operator then has to push the crane to the lowering point, for lowering and disconnecting from the crane, taking considerable time. Thus the development is aimed a making this work more efficient.
In an existing lifting system the operator holds a pair of handles with both hands as he lifts the engine using the hoist to which the handles are attached, so the handles rise with the hoist, forcing the operator to extend both arms upwards. In this case the handles may reach up to 1.58m – a long reach for some individuals. Repetitive stretches and arm movements can be tiring, especially as the movements are non-powered.
Description
The patent describes the apparatus in detail and also discloses a method of controlling it with intuitive controls for positioning the hoist accurately over the loading and unloading position, including any position on moving conveyors.
Fig 1 – Side view of an ergonomic hoist system of the invention
In Fig 1 the improved hoist (100) is shown in an assembly plant in which the floor (101) and horizontal hoist assembly support (103) are shown. The latter may be a structural part of the manufacturing plant. With an ‘I’ beam to facilitate hoist motion along a major axis. The hoist has one or more roller assemblies (107) moving along and secure to the main horizontal support. Each should have a drive to power the hoist motion, with control by the operator or an automated positioning system. If the loads are small enough the roller assemblies need not be powered if the operator can provide the movement without undue strain using force within recommended ergonomic ranges.
The hoisting equipment includes a lift assembly (11) connected to the roller assemblies with a structural frame (113) of any suitable construction to support the load, load assembly (115) and an electronic module (117). The construction portrayed in the patent has a load weight limit of 2,500kg but other designs for smaller or larger loads are possible.
The load assembly includes a lift piston (119), a lift arm (121), a vertical guide assembly (123), a vertical position sensor and a vertical brake. The lift piston moves the support assembly vertically with pneumatic, hydraulic or mechanical action. The support assembly is connected to the lift assembly through the lift piston and the lift arm. The vertical guide assembly (123) ensures axial motion of the support assembly with respect to the assembly when moved by the lift piston. The vertical position sensor is connected to the electronic module and in turn to the vertical brake. The latter can stop and hold the lift arm in position with respect to the vertical guide assembly.
The support assembly has an upper support (127) and lower support (129). The upper support assembly includes an angular position motor (131) and a support plate (133), shown connected to the lift arm and lift piston, and with the position motor connected to the support plate. The lower support is connected to the support plate with a rotatable attachment allowing rotation movement with respect to the lift assembly by the angular position motor with pneumatic, hydraulic or mechanical drive.
Fig 2 – Side view of the hoist system with the load in an upper position
The rotational position sensor is placed between the support plate and lower support and is electronically connected to the electronic module, as is the angular position motor. The latter can stop the lower support and hold it in position with respect to the support plate, or a rotational position brake can also be used with electronic control and connected to the electronic module. Variable frequency drive motors can be used in the hoist to vary its speed in horizontal or vertical directions.
The operator assembly (135) is connected to the support assembly through a support arm (137), which is free to rotate about the same axis as the engine support. Alternatively it can have a rigid connection, or be free to rotate about a different axis. The operator assembly includes a frame (139), adjustment piston (141), control interface (143), operator panel (145) and handles (147). The frame is connected on a slide to the support arm.
A height adjuster can change the relative position of the support arm and frame. The control interface has a number of electronic switches and displays to allow an exchange of information and commands between the operator and electronic module. The operator panel has a sliding connection with the frame, and the adjustment piston controls the relative position.
The handles connected to the operator panel include switches to enable the operator to control the position, orientation and operation of the hoist. As shown in Fig 2 the operator (701) stands next to the operator panel and holds the handles. An engine load is connected to the support assembly through the lower support. Engines typically have lifting eyes attached to the engine with holes through which the engine is engaged and lifted. The lower support may have retractable rams operated by a switch in the handles. These can be extended through the engine lifting eyes to hold the load during transport.
The patented equipment can maintain and ergonomic and comfortable position for the operator panel relative to the operator during operation. When the support assembly is in a low position, the lift position and lift arm are extended, the support arm is positioned low on the frame of the operator assembly. The adjustment piston is retracted to keep the control interface and panel at a height comfortable for the operator. In Fig 2 the support assembly is in a retracted or lift position (303). Here the lift piston and lift arm are retracted, and the support arm is positioned high on the frame of the operator assembly. Now the adjustment piston is extended to maintain the control interface and panel at substantially the same height for the operator as previously.
Controls
Fig 3 – Operator’s view of the hoist control panel
Fig 3 shows the operator panel as seen by the operator with the main interface (401) and a master switch (403). Handle supports (405 and 407) are connected to the frame. The handle themselves are attached near the end of the supports.
Fig 4 – Perspective views of the operator handles with hoist control switches
Fig 4 shows the handles in detail. In Fig 4A, button 413 can be actuated by the left thumb, for example, to grip the load by actuating rams on the lower support. A second button (415) can release the load for example. A third (417) and fourth button (419) can be pressed to move the hoist in tow horizontal directions. These buttons can also be part of a single, dual-position switch. Thumb operation requires less force for more comfortable operation.
The right handle (Fig 4B) has switches actuated by the operator’s right hand, with buttons 421 and 423 pressed to move the hoist in two vertical directions. Buttons 425 and 426 can move the hoist in two more horizontal directions.
The handles may also have one or more dead-man switches located where the operator grips the handles or on the far side of each handle. When the dead-man switch is released the hoist automatically stops, plus any other desired function at the same time. Each handle can be ergonomically shaped for ease of operation with switch positioning close to the operator’s fingers. Buttons can also be designed for ‘one-time activation’ for a feature to be accomplished by a single push rather than continuous depression.
Method
The patent disposes a flow chart for one method of transporting a load starting with positioning the hoist over the first position, such as a conveyor belt. The hoist can compensate automatically for motion of the load such as on a moving conveyor system. The hoist is lowered over the load whilst maintaining the operator panel at substantially the same height throughout the whole movement of the load.
The load is attached to or gripped by the hoist, which raises it whilst moving the load. The hoist is then moved to above the second load position. The hoist can also be capable of moving to another position past the first position to allow for manufacturing flexibility if, for example, a load lying on the conveyor system is deemed defective or incomplete, and requires removal to a second conveyor system for reworking. The hoist can also automatically compensate for movement of a second conveyor.
The load is lowered and deposited onto the second position, again maintaining the operator panel at the same height throughout the process. The load is then released. The overall hoist movement may include one or more horizontal directions and/or one or more vertical directions.
Ergonomic advantages
Maintaining the operator panel at substantially the same height within a narrow range provides ergonomic operation of the hoist so that, for examples, the operator need not reach or bend in ways that may stress the arms or lower back. It is intended that the range of movement be within 150-200mm of a chosen height of the operator but larger or smaller ranges can be utilised to accommodate other circumstances.
It is also intended that the patent cover the handling of loads other than engines, with ergonomic operation reducing downtime compared to traditional hoists. Power-assisted motion of the hoist allows operators to manoeuvre and position loads at faster rates, decreasing cycle times. Load manipulation also becomes an easier operation that is more desirable for operators.
About the patent
This article is an edited version of WIPO international patent application number WO/2007/008331, published on January 18 2007, and also published as European Patent EP1/904/395 A0. The national equivalent patent is US2007/063173. The inventors are Zachary Fijal of Brookfield, Jeffrey Schueller of Streamwood, Sanjay Patel of Bartlett and Andrew Filipial of Gurnee, all Illinois, US. The applicant is the International National Engine Intellectual Property Co., which holds a large number of patents related to automotive components and their manufacture. The company is a wholly owned subsidiary of the International Truck & Engine Corporation.
Disclaimer
This article and accompanying illustrations are edited versions of the patent and may omit legally or technically important text or details.
