Abstract:
An apparatus which forms a controlled engageable low maintenance seal between the slide and the gib of a mechanical press and which prevents lubricant from exiting the area between the slide and the gib and entering the die space. The sealing arrangement is selectively actuatable depending upon an operational condition of the press.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application relates to and claims the benefit under 35 U.S.C. § 119 of Provisional Application Serial No. 60/159,717 filed Oct. 15, 1999 by the same inventor. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to seals for use in a mechanical press and more particularly to seals which are selectively engageable and have low maintenance requirements. Specifically, this invention relates to the use of selectively engageable seals to control lubricant leakage in a mechanical press. 
     2. Description of the Related Art 
     Mechanical presses of the type performing stamping and drawing operations employ a conventional construction that includes a frame structure having a crown and a bed and which supports a slide in a manner enabling reciprocating movement toward and away from the bed. Conventional presses additionally include a gib. A gib is a mechanism in stamping or drawing presses which works to contain the lateral motion of a reciprocating slide in a direction substantially normal to the direction of the slide&#39;s reciprocating movement. 
     Press machines are widely used for a variety of workpiece operations and employ a large selection of die sets, with the press machine varying considerably in size and available tonnage depending on its intended use. 
     State of the art mechanical presses provide lubrication between the gib and the slide to facilitate and contain slide movement. The lubrication contained between the slide and the gib has a tendency to be pushed out and may leak onto the bed of a press. Factors such as press speed, tipping moment, applied load, and wear contribute to the likelihood of lubrication leaks. 
     Lubrication from portions of a mechanical press contained in the crown (among other places) may leak into the area between the slide and the gib. Additional lubricant entering the area between the gib and the slide exacerbates the problem of lubrication exiting the area between the gib and the slide and possibly finding its way onto the bed of the mechanical press. Leaking lubricant from other portions of a mechanical press (e.g. the crown) may also leak into other portions of the press (e.g. the bed) and cause problems. 
     Leaking lubricant may pass from the gib, down the slide and onto the parts being stamped on the press. In some production environments, oil leaks will cause scrapping of stamped product which leads to increased cost and production time. 
     Different sealing arrangements have been utilized in an effort to prevent lubricant from contacting stock material in a mechanical press. Current state of the art seals include seals which have flexible wiper portions which experience mechanical wear. This mechanical wear causes these seals to fail and leak. Frequent removal and replacement of these seals necessitate that the press be off-line and disassembled to obtain service access to the gib assembly. 
     What is needed in the art is a seal mechanism for sealing the area between the gib and the slide of a mechanical press in which the seal mechanism is adjustable controlled, and does not require frequent maintenance. 
     What is additionally needed in the art is a seal mechanism for a mechanical press which is selectively actuatable depending upon the operating condition of the mechanical press. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to improve upon the aforementioned mechanical press sealing mechanisms, wherein it is desired to prevent lubricant from contacting stock material without experiencing frequent down time for seal replacement. The present invention also improves upon the current state of the art sealing mechanisms for a mechanical press by providing a selectively actuatable sealing arrangement which is responsive to press operational condition. 
     The present invention provides a seal mechanism for a mechanical press which includes seal surfaces which can be selectively engaged and are made from a highly wear resistant, low friction material. 
     The invention, in one form thereof, comprises a press which includes a sealing mechanism. The press includes a bed which is connected to a pair of uprights. The uprights are further connected to a crown. In this form of the current invention, the press includes a gib attached to the press and a selectively inflatable seal. The selectively inflatable seal is connected to the press and can be disposed between the slide and the uprights, the slide and the crown, or the slide and the gib. 
     The invention, in another form thereof, comprises a press which includes a selectively inflatable seal. In this form, an inflator selectively inflates the linear seal. A controller, which selectively actuates the inflator may be employed. The controller receives values corresponding to press operational condition and signals the inflator to inflate the linear seals when one of the values exceeds a predetermined measure. The values received by the controller include, for example, a measure of press tipping moment, a measure of applied load, a measure of press speed and/or a measure of sensed oil leaks. 
     The invention, in another form thereof, comprises a press including a press frame. A slide is mounted within the frame for reciprocation relative to the frame. A gib is connected to the frame and a plurality of linear seals are located between the gib and the slide and selectively form a cavity therebetween. In one form of the current invention, the linear seals are lengthwise substantially parallel to the direction in which the slide reciprocates. 
     The invention, in another form thereof, includes a plurality of wear plates which have wear plate contact surfaces and which maintain a position between the slide and the gib. The wear plates are connected either to the slide or the gib and are configured such that the wear plate contact surfaces are opposite and substantially parallel to gib contact surfaces or slide contact surfaces, respectively. A plurality of linear seals selectively form a cavity with the gib and the slide. The plurality of wear plates are located within the cavity. In one form of the current invention, the wear plates have a surface finish that is approximately within the range of 16 to 32 microfinish. 
     The invention, in another form thereof, includes a plurality of linear strips of wear material which are affixed to a plurality of linear seals such that when the linear seals are actuated, the linear strips of wear material contact the slide and form the seal contact surface. The strips of wear material are formed from a highly wear resistant, low friction material which can be, for example, TEFLON or TURCITE. 
     The invention, in another form thereof, comprises a press which includes a press frame. A slide is mounted within the frame for reciprocation relative to the frame and a gib is connected to the frame. A plurality of linear seals selectively form a cavity with the gib and the slide. A collection means, for example, a collection tray, collects lubricant from the cavity. 
     The invention, in another form thereof, comprises a press including a plurality of inflatable linear seals which selectively form a cavity with the slide and the gib of the press. In this form, an inflator selectively inflates the linear seals. A controller, which selectively actuates the inflator may be employed. In one form of the current invention, the controller receives values corresponding to press operational conditions and signals the inflator to inflate the linear seals when one of the values exceeds a predetermined measure. The values received by the controller include, for example, a measure of press tipping moment, a measure of applied load, a measure of press speed and/or a measure of sensed oil leaks. 
     The invention, in another form thereof, comprises a press which includes a press frame. A slide is mounted within the press frame for reciprocation relative thereto. A gib is connected to the frame and includes a plurality of linear grooves. A plurality of linear seals occupy the grooves in the gib and selectively form a cavity with the gib and the slide. The plurality of linear seals comprise a plurality of linear strips of steel which have sealing surfaces. A plurality of linear strips of wear material are affixed to the sealing surfaces of the plurality of linear strips of steel. In this form, the linear grooves include pressure chambers which selectively apply a pressure to the linear seals causing the linear seals to form a cavity with the gib and the slide. 
     The invention, in another form thereof, comprises a press which includes a press frame. A slide is mounted within the press frame for reciprocation relative thereto. A gib is connected to the frame and a linear seal surrounds the slide and selectively forms a seal between the slide and the gib. 
     The invention, in another form thereof, comprises a press. The press includes a frame and a slide mounted within the frame for reciprocation relative thereto. The slide has four corners each of which has a front-to-rear and a left-to-right touch surface. A plurality of wear plates having wear plate contact surfaces are affixed to each of the touch surfaces of the slide. In this form, the invention includes a plurality of seal contact blocks which correspond in number to the wear plates. One of said plurality of seal contact blocks extends outwardly from each wear plate. A gib is affixed to the frame and has a plurality of gib contact surfaces corresponding in number to the wear plates. The gib contact surfaces are opposite and substantially parallel to the wear plate contact surfaces. A plurality of inflatable linear seals are connected to the gib. One of the plurality of linear seals selectively contacts each of the contact blocks. In this way, the linear inflatable seals form four sealed cavities one at each of the four corners of the slide. Each of the sealed cavities vertically encloses the front-to-rear and the left-to-right touch surface at each corner of the slide. A linear strip of wear material is affixed to each of the linear seals such that it forms the surface of the linear seal which contacts the slide. A collection tray is configured for collecting lubricant from each of the sealed cavities. 
     An advantage of the present invention is the ability to prevent lubricant from contacting stock material without utilizing a sealing arrangement which requires frequent maintenance. 
     Another advantage of the present invention is that the seals of the present invention may be selectively engaged depending upon the operational condition of the mechanical press. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a front elevational view of a mechanical press incorporating the sealing arrangement of the present invention; 
     FIG. 2 is a top sectional view of the slide and the gib of a mechanical press including an embodiment of the sealing arrangement of the current invention; 
     FIG. 3 is a top sectional view of the slide and the gib of a mechanical press including an embodiment-of the sealing arrangement of the current invention; 
     FIG. 4 is a top sectional view of the slide and the gib of a mechanical press including an embodiment of the sealing arrangement of the current invention; and 
     FIG. 5 is a top sectional view of the slide and the gib of a mechanical press including an embodiment of the sealing arrangement of the current invention. 
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings and particularly to FIG. 1, mechanical press  10  comprises a crown assembly  12 , a bed  14  having a bolster assembly  16  connected thereto and uprights  18  connecting crown assembly  12  with bed  14 . Uprights  18  are connected to or integral with the underside of crown assembly  12  and the upper side of the bed  14 . Tie rods  20  extend through crown assembly  12 , uprights  18  and bed  14  and are attached on each end with tie rod nuts  22 . Leg members  24  are formed as an extension of bed  14  and are generally mounted on the shop floor  28  by means of shock absorbing pads  26 . 
     Drive mechanism  30  is attached to crown assembly  12  of mechanical press  10  and connected by a clutch/brake mechanism (not shown) to a standard crankshaft (not shown) to which connecting rods  32  are attached. A slide  34  is operatively connected to connecting rods  32 . During operation, drive mechanism  30  rotates the crankshaft (not shown) which operates the eccentrically connected connecting rods  32  to cause slide  34  to reciprocate in a rectilinear fashion toward and away from bed  14 . 
     FIG. 2 illustrates an embodiment of the seal mechanism of the current invention. Specifically, FIG. 2 illustrates an embodiment of the sealing arrangement utilized at a corner of slide  34 . A seal mechanism in accordance with the current invention could be utilized at each corner of slide  34 . As slide  34  reciprocates during press operation, the sealing arrangement of the current invention works to prevent lubrication from exiting-the area between slide  34  and gib  50 . 
     Slide  34  includes front-to-rear touch surface  88  and right-to-left touch surface  90 . Front-to-rear wear plate  52  is connected to slide  34  at front-to-rear touch surface  88 . Right-to-left wear plate  54  is connected to right-to-left touch surface  90  of slide  34 . Front-to-rear wear plate  52  includes front-to-rear wear plate contact surface  60 . Right-to-left wear plate  54  includes right-to-left wear plate contact surface  62 . 
     Gib  50  includes gib contact surfaces  66  which are opposite and substantially parallel to front-to-rear wear plate contact surface  60  and right-to-left wear plate contact surface  62 . Seal contact blocks  86  are connected to slide  34  and have a surface finish that is approximately within the range of 16 to 32 microfinish. 
     Linear inflatable seals  56  are connected to gib  50  and include wear material  70  positioned on the sealing surface of linear inflatable seals  56 . Inflator  74  is operatively connected to linear inflatable seals  56 . Controller  76  is communicatively connected to inflator  74 . 
     During press operation, controller  76  will signal inflator  74  to inflate linear inflatable seals  56  when necessary. Upon actuation, linear inflatable seals  56  will contact seal contact blocks  86  and form a sealed cavity  64 . Collection tray  72  is operatively located beneath sealed cavity  64 . In some embodiments, the cavity may remain open at particular locations to control captured oil flow. 
     Controller  76  may be manually operated or may receive signals corresponding to the operational state of the press from sensors (not shown) and automatically signal inflator  74  to actuate linear inflatable seals  56  when a particular press operational value exceeds a predetermined measure. Such sensed values can include values corresponding to press tipping moment, applied load, press speed, or sensed oil leaks. 
     FIG. 3 illustrates another embodiment of the sealing arrangement taught by the current invention. In this embodiment, linear inflatable seals  56  are connected to gib  50  through seal mounting blocks  92 . In this embodiment, linear inflatable seals  56  have a sealing surface which contains wear material  70 . Upon inflation of linear inflatable seals  56 , wear material  70  contacts front-to-rear wear plate  52  and right-to-left wear plate  54  and forms sealed cavity  64 . 
     FIG. 4 illustrates another embodiment of the sealing arrangement of the current invention. In this embodiment, front-to-rear wear plate  52  and right-to-left wear plate  54  are connected to gib  50 . Slide  34  includes slide contact surfaces  68  which are opposite and substantially parallel to front-to-rear wear plate contact surface  60  and right-to-left wear plate contact surface  62 . Linear inflatable seals  56  are connected to gib  50  by way of seal mounting blocks  92  and selectively form sealed cavity  64 . 
     FIG. 5 illustrates an embodiment of the current invention which utilizes linear seals  58 . Linear seals  58  are formed from linear strips of steel which have sealing surfaces. Wear material  70  is connected to the sealing surfaces of linear seals  58 . Gib  50  includes linear grooves  78  which house linear seals  58 . Linear grooves  78  include bearings  82  and pressure chambers  84 . Inflator  74  is operatively connected to pressure chambers  84  and is communicatively connected to controller  76 . 
     Slide  34  includes front-to-rear touch surface  88  and right-to-left touch surface  90 . Front-to-rear wear plate  52  and right-to-left wear plate  54  are connected to front-to-rear touch surface  88  and right-to-left touch surface  90 , respectively. 
     Gib  50  includes gib contact surfaces  66  which are opposite and substantially parallel to front-to-rear wear plate contact surface  60  and right-to-left wear plate contact surface  62 . Upon actuation, linear seals  58  form sealed cavity  64 . Collection tray  72  is operatively located to receive lubrication exiting sealed cavity  64 . 
     While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.