Presses – Methods
Reexamination Certificate
2001-06-06
2004-02-10
Ostrager, Allen (Department: 3725)
Presses
Methods
C100S25800A, C100S269170, C384S039000
Reexamination Certificate
active
06688216
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a press machine environment, and, more particularly, to a system for monitoring the gib-slide interface to detect the presence of a clearance therebetween and to initiate a procedure for adjusting the clearance in a controlled manner, using a process that selectively pressurizes a pressurized chamber combination disposed in actuating relationship to the press gib.
2. Description of the Related Art
Mechanical presses of the type performing stamping and drawing operations have a conventional construction comprising a crown and a bed portion configured within a frame structure. A slide supported within the frame is adapted for reciprocating movement toward and away from the bed. The slide is driven by a crankshaft having a connecting arm coupled to the slide. These mechanical presses are widely used for a variety of workpiece operations employing a diverse array of die sets, with the press machine varying substantially in size and available tonnage depending upon its intended use.
In a conventional arrangement, the frame structure is formed and/or integrated with a gib apparatus having a known function and configuration. For example, in a typical machine configuration, the frame includes a set of upright support members (e.g., four) extending between the crown and bed at respective corner locations. Transverse cross-beams are used to provide a connection between a pair of same-side uprights. At the upper portion of each upright, a gib member is employed in a known manner to provide guidance-type bearing support to the slide. For example, the gib member includes an engagement surface that is adapted for full surface-to-surface abutting contact with a corresponding surface on the slide or a coupling piece secured to the slide.
In one gib configuration, the individual gib members are mounted to a respective upright. Although designed as stationary structures, the uprights may nevertheless experience an undesirable bending or outward bowing under certain conditions. For example, this bending may occur at the upper ends of the uprights as the crown expands in response to certain thermal conditions within the machine environment, such as significant variations or increases in temperature. These environmental factors are difficult to avoid and/or overcome because press operations inevitably involve a dynamic confluence of extremely high pressures and temperatures that make it difficult to isolate individual machine components from their effects, particularly with respect to a component as massive as the press crown. Temperature changes also effect the slide and bed.
The significance of this bending behavior of the upright is seen in the fact that the attached gib member will move in concert with the upright. In particular, any deflection of the upright causes a simultaneous displacement of the attached gib member, which necessarily rearranges the precise spatial relationship between the gib and slide. Under conditions where the upright bows outwardly (i.e., away from the slide), the concurrent movement of the gib will cause a spatial separation or clearance to develop at the interface between the gib and slide, where previously these components were in abutting engagement with one another in a bearing support relationship.
The absence or diminution in the bearing support provided by the gib to the slide can present various problems. For example, if the slide is inadequately supported, as may arise when certain gib elements experience movement creating an unbalanced support configuration, the slide may deviate from its planned course of travel as it reciprocates between the crown and bed. Malfunctions or misalignments involving the slide can lead to press failure and die damage.
SUMMARY OF THE INVENTION
An adjustment mechanism for use in a press machine environment is used to vary the spatial relationship between the slide and gib member mounted on the press upright. Adjustment of the gib-slide clearance is part of a compensation scheme aimed at counteracting the bowed or spatial change relative to the slide condition of the uprights that may arise from thermal expansion of the crown, bed, or slide portion, causing the clearance between the gib and slide to increase or decrease.
In one form of the invention, the gib is adapted to include a pressurized chamber, such as, for example a piston-cylinder combination contained within a receptacle area or housing space formed by the gib. A sensor measures a clearance between the gib and slide. A determination is made regarding whether this clearance measurement has exceeded an allowable threshold value. In response to an out-of-bounds determination, a controller injects pressurized oil into a pressurization chamber to create a directional actuating force which effectuates an inward or outward displacement of the gib toward the slide (e.g., via elastic bending of the gib). This gib movement counteracts the prior displacement of the gib resulting from bowing of the upright. The clearance between the gib and slide is therefore substantially restored to a normal condition, e.g., a minimal clearance condition.
The adjustment mechanism preferably forms part of an automated closed-loop feedback system that dynamically and continuously monitors the gib-slide clearance and appropriately regulates the pressurization level of the piston-cylinder combination in accordance with a comparison of the clearance measurement to allowable data values. Adjustment of the gib clearance preferably occurs during a running press cycle.
In another form, an adjustment mechanism comprises, in combination, a hydraulically activatable pressurized chamber, such as a piston-cylinder combination operatively associated with the gib, such piston-cylinder combination being responsive to changes in its pressurization to actuatively induce an elastic deformation of the gib sufficient to close-out the clearance between the gib and slide. The mechanism further includes a sensor to measure the gib-slide clearance, and a controller to vary the hydraulic pressurization according to the sensor clearance measurement. The system preferably defines an automated, closed-loop feedback configuration offering dynamic and continuous monitoring and adjustment of the gib-slide clearance.
The invention, in another form thereof, is directed to an assembly for use in a machine comprising a movable machine member and a frame to guide the movable machine member, wherein the frame includes a gib.
The assembly comprises at least one selectively pressurizable piston-cylinder combination each operatively associated with the gib, each piston-cylinder combination operatively actuating movement of at least a portion of the gib upon activation thereof. The assembly further includes a control system to control operation of the at least one piston-cylinder combination.
In one form, the cylinder of each respective piston-cylinder combination is defined at least in part by a respective portion of the gib. The frame preferably includes at least one upright support member, wherein each piston-cylinder combination is arranged to have one end of the cylinder thereof being disposed opposite a portion of a respective upright support member. Accordingly, during operation, at least one piston-cylinder combination is selectively activated to urge the respective piston against the respective upright support member associated therewith, thereby effectively inducing displacement of at least a portion of the gib at least towards the movable machine member.
In one form, the control system includes a sensor to provide a measure of the spatial relationship between the gib and the movable machine member; and a controller to control the pressurization of the at least one piston-cylinder combination, using the spatial measurement provided by the sensor. In a preferred form, the piston-cylinder combination and the control system cooperatively define a feedback configuration. The sensor spatial measurement preferably defines a possible clearance betw
Knuth Randall J.
Ostrager Allen
Self Shelley
The Minster Machine Company
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