Traversing hoists – With motor control – In control cab
Reexamination Certificate
1998-03-13
2001-02-27
Brahan, Thomas J. (Department: 3652)
Traversing hoists
With motor control
In control cab
C212S291000, C212S344000
Reexamination Certificate
active
06193086
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to cranes, and more particularly to circuitry and apparatus which are manually variable for controlling moveable components of the crane, such as booms, lift frames, winches, trolleys, hydraulic cylinders, hydraulic motors, valves, and wheels which move the cranes.
BACKGROUND OF THE INVENTION
Cranes, such as gantry cranes are used for lifting and handling loads. In particular, gantry cranes are used to lift such as truck trailers, cargo containers, boats and the like. The cranes normally have a gantry structure that spans over the load(s). For example, in intermodal applications, the crane may span over two adjacent railroad cars, a truck trailer adjacent a railroad car or side-by-side stacks of containers. Gantry cranes are frequently self-mobile, moving on tracks or wheels.
Conventionally, some sort of apparatus, such as a lift frame or a lifting yoke, is suspended from the gantry structure to engage and lift loads. Such apparatus must be moveable at least up and down. For intermodal applications the apparatus is also preferably moveable side-to-side and may be tilted end-to-end and side-to-side.
Movement of the crane itself and its moving components is generally accomplished directly, or indirectly, by the operator using control circuitry and apparatus which is manually-actuated and articulated to achieve desired variable speeds and directions. Controls, such as, joysticks, manually-rotatable wheels or roller balls, foot pedals and the like are moved and positioned by an operator. The movement and position are translated into a control signal to move and position a given component of the crane itself.
These controls must provide a wide range of control. For example, to engage loads and to maneuver in limited spaces, the controls must provide for slow and careful movement of the crane and its components. On the other hand, because of the high duty cycles required for efficient commercial operations, the controls must also provide for higher speeds when such precision of movement is not required. Also, for speed and efficiency of operation, an operator must be able to quickly and continuously vary the speeds from low to high and any appropriate speeds in-between.
Accordingly, conventional control systems provide manual controls permitting a continuous range of vehicle and component movement speed from a minimum to maximum speed which is relatively broad. Thus, accuracy and consistency of speed and direction affected by the manual controls on the vehicle or a given component is a function of the physical acuity of the operator attempting to physically position the control appropriately between its maximum and minimum value.
This poses a problem during operations which require a great deal of very precise, or slow, movement such as encountered by operators when positioning the crane or its lifting apparatus for proper engagement with, or over, a load.
For example, when using a conventional joystick to control the crane or its other moveable components, the operator can repeatedly overshoot, or undershoot, the position desired to properly align a lifting apparatus over the load. This is particularly problematic when twist locks are involved where all four corners of a lifting apparatus must be aligned with all four upper comers of a container to be lifted. Using the mechanical range and variable response of a conventional joystick to properly align the twist locks can be difficult and time consuming.
Another example of an operation which requires precision of speed and direction of movement is found in marine applications where the crane wheels must be directed on narrow sea walls in order to position the crane over a boat in the water. Such sea walls are frequently not much wider than the wheels of the crane and a small control error by the operator could be disastrous.
The present invention is proposed to solve these problems and to provide other advantages not provided in the same manner by conventional apparatus.
SUMMARY OF THE INVENTION
The present invention provides a control apparatus which changes the response of a moveable component of a gantry crane or the gantry crane itself, to a manually-articulable control when more precision of movement is desired. More particularly, a means is provided for changing the response to a given manual control when the means is activated. The means may either scale the range of response or provide a single constant output in response to manual activation.
In one embodiment of the invention, electronic circuitry, in the form of first and second control circuits, is used to control the rate, amount or direction of movement of the component or components. A manually-articulable control is provided which has a physical, mechanical range of movement. The manually-articulable control can be switched between the first and the second control circuits.
When connected to the first control circuit, a first range of control signals is generated in response to the manually-articulable control, the value of the signal corresponding to the mechanical range of manipulation of the control. Thus, when the first circuit is connected to the manually-articulable control, the control signal is dependent upon, and proportional to, a crane operator's manual articulation over the entire mechanical range of manipulation of the control. Accordingly, the rate and amount of movement of the moveable component are proportional to the crane operator's manual input over the mechanical range of manipulation of the manually-articulable control between a maximum and a minimum speed or amount of response.
When the manually-articulable control is connected to the second control circuit, a preset control signal is produced in response to any motion or position of the manually-articulable control after actuation. Thus, regardless of the precision or steadiness of the operator's physical manipulation of the manually-articulable control, the movement of the component is at a constant speed. Alternatively, the second circuit could be separately controlled by a second control.
In another embodiment of the invention, when the manually-articulable control is connected to the second control circuit, a second range of control signals is produceable in response to manipulation of the manually-articulable control over its entire range of manipulation. The second range of control signals is scaled to be a fraction of the first range of control signals. In other words, over the entire range of mechanical manipulation of the manually-articulable control, the first control circuit will produce movement of the moveable component from a minimum speed to a maximum speed. On the other hand, over the entire range of physical manipulation of the manually-articulable control, the second control circuit will produce movement of the moveable component from the minimum speed only up to a fraction of the maximum speed provided by the first control circuit.
According to another aspect of the present invention, the second control circuit has a means for variably adjusting the scaling of the second range of control signals or adjusting the preset constant speed control signal.
According to another aspect of the invention, means are provided to permit the operator to select either a second range of control signals, or a single preset signal provided by second and third control circuits.
According to another aspect of the invention, conveniently operable and accessible means are provided for switching between the first and second circuits.
Other advantages and aspects of the present invention will become apparent upon reading the following description of the drawings and detailed description of a preferred embodiment of the invention.
REFERENCES:
patent: 3856102 (1974-12-01), Queen
patent: 4638883 (1987-01-01), Morizumi et al.
patent: 4700802 (1987-10-01), Fought
patent: 4995472 (1991-02-01), Hayashi et al.
patent: 5957235 (1999-09-01), Nishimura et al.
patent: 5996341 (1999-12-01), Tohji
patent: 5996722 (1999-12-01), Price
Feider Thomas H.
Gunnlaugsson Robbie M
Brahan Thomas J.
Marine Travelift, Inc.
Wallenstein & Wagner Ltd.
LandOfFree
Gantry crane with improved manually variable controls for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Gantry crane with improved manually variable controls for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gantry crane with improved manually variable controls for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2594284