Abstract:
A vacuum cup construction designed to support large items includes a planar outer plate, and a planar, generally coincidentally shaped inner plate which is smaller than the outer plate. A generally flat coincidentally shaped compressible unmolded, non-preformed sealing member, which is larger than the inner plate, is retained between the outer and inner plates by a threaded stud and a threaded nut connecting the outer and inner plates, the tightening of which compresses the sealing member. Compression of the sealing member causes the periphery to deform and form a sealing edge. A vacuum passage passes through the outer plate, the sealing member, and the inner plate to permit a vacuum to be drawn when the assembly is placed against the surface of an item or object.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The field of the invention comprises devices generally known as vacuum support cups. 
     2. Description of the Prior Art 
     Heretofore various constructions have been proposed for vacuum cups of the type which are attached to an object for lifting of that object. Vacuum cups are used, for example, for attachment to plate glass from a supporting or lifting device. A known prior art vacuum cup construction comprises a solid rubber cup with a central vacuum port which permits a vacuum to be drawn within the cup. Another embodiment comprises a solid rubber cup laminated to a metal backing. A third embodiment employs two metal plates which clamp upon a preformed solid rubber sealing ring to form a cup upon which a vacuum may be drawn. A fourth embodiment comprises a structure similar to the third embodiment that has been modified by laminating a soft rubber ring to the edge of the solid rubber cup. Yet another embodiment in the prior art comprises a single metal plate with a soft rubber ring laminated to the base of the metal plate for purposes of supplying a vacuum seal. In all instances, a cup is formed with a flexible edge to engage an object and a vacuum port is connected to the inside of the cup whereby the cup may be evacuated to effect attachment of the cup to an object. There as remained, however, the need for an improved vacuum cup construction. 
     SUMMARY OF THE INVENTION 
     Briefly the present invention comprises an improved vacuum cup construction which includes an outer plate and an inner plate wherein the inner plate is smaller than the outer plate. The construction also includes a compressible sealing member between the outer and inner plates wherein the sealing member is larger than the inner plate, means for connecting the outer plate to the inner plate to compress and form the sealing member and thereby define a sealing edge, and at least one tube passing through the sealing member, the outer plate and the inner plate adapted for connection to a vacuum source. 
     This device has at least three major advantages over the prior art. First the sealing member may be quickly replaced by a new member when the sealing edge is no longer able to sustain a vacuum. This allows for significant savings in the time and cost to replace a cup associated with prior art constructions when it is worn and no longer able to sustain a vacuum. A second major advantage is that the sealing member is reusable. In the preferred embodiment the opposite flat side of the sealing member may be used to create a second sealing edge by simply reversing the sealing member and replacing it between the outer and inner plates. Thus, the sealing member has twice the life, resulting in a significant savings in the cost of vacuum cups. A third major advantage is that the sealing member requires no molding or preforming. By contrast, in the prior art vacuum cups, the sealing member has a molded, preformed cup shape. In the present invention the cup shape is caused by differential compression of the sealing member between the inner and outer plates. Thus, no preforming of the sealing member is necessary. This results in a significant savings in the cost of manufacturing the sealing member. 
     Thus, it is an object of the invention to provide an improved vacuum cup construction. 
     Yet a further object of the invention is to provide an improved vacuum cup construction comprised of a plurality of parts including a pair of generally planar opposed parallel plates which are generally coincidentally shaped and have a flexible, elastomeric sealing member retained between the plates. 
     Yet another object of the invention is to provide an improved vacuum cup construction comprised of generally coincidentally shaped planar plates wherein one of the plates has a generally smaller size than the other plate and further wherein a flexible elastomeric sealing member is retained by compression between the plates. 
     Yet a further object of the invention is to provide a sealing cup construction having a simplified construction which may be easily repaired. 
     Yet a further object of the invention is to provide an improved vacuum cup which may be assembled utilizing a variety of materials. 
     Yet a further object of the invention is to provide a vacuum cup construction wherein the sealing characteristics associated with the vacuum cup may be altered by substitution of the particular elastomeric sealing material utilized in the sealing member of the vacuum cup construction. 
     Still another object of the invention is to provide an efficient, economical vacuum cup construction. 
     These and other objects, advantages and features of the invention will be set fourth in a detailed description as follows: 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     In the detailed description which follows, reference will be made to the drawing comprised of the following figures: 
     FIG. 1 is a perspective view of the assembled vacuum cup of the invention; 
     FIG. 2 is a perspective view of the inner plate associated with the vacuum cup of the invention; 
     FIG. 3 is an perspective view of the outer plate associated with the vacuum cup of the invention; 
     FIG. 4 is a perspective view of the elastomeric sealing member associated with the vacuum cup of the invention wherein FIGS. 2, 3 and 4 are juxtaposed with respect to one another to depict an exploded view of the construction of FIG. 1; 
     FIG. 5 is a side cross-sectional view of the construction of FIG. 1; 
     FIG. 6 is a perspective view of an alternative configuration of a vacuum cup construction incorporating the principals of the invention; 
     FIG. 7 is a perspective view of yet a further embodiment incorporating the principals of the invention; 
     FIG. 8 is a perspective view of a further embodiment incorporating the construction principals of the invention; and 
     FIG. 9 is a cross-sectional view of the vacuum cup as it is attached to the surface of an object by means of a vacuum. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 is a perspective view of a preferred embodiment of the invention. The three major elements of the cup include (1) an inner plate 10, (2) an outer plate 12 and (3) an intermediate sealing member 13. The combination is designed so both the outer plate 12 and the sealing member 13 have an effective area larger than that of the inner plate 10. The sealing member 13 is placed on the inner plate 10 so that a passage 14 is associated with a threaded stud 15 projecting from the plate 10. The outer plate 12 is attached to this assembly via a passage 16 which fits over the threaded stud 15. The combination is secured by means of a threaded nut 17. The tightening of said threaded nut 17 onto the threaded stud 15 secures the combination and causes compression of sealing member 13 between plates 10 and 12. This compression forces that part of the sealing member 13 that extends over the edge of the inner plate 10 down around the edge of the inner plate 10. This creates the cup formation with a depth 18. The cup is placed on the surface of an object and a vacuum is drawn through a vacuum port or passage 19. The vacuum causes the cup to attach itself to the object along a peripheral sealing edge 20. 
     FIG. 2 is a depiction of the inner plate 10. The inner plate 10 is generally planar; however it not restricted to a simple flat plane. It may take the shape of many complex planes such as a cylindrical plane or a spherical plane. The inner plate 10 is constructed of a rigid material, generally aluminum or steel, but the material may vary with the application. In the preferred embodiment the inner surface 11 of the inner plate 10, is laminated with a rubber coating 21 to protect the surface of the object. Attached to the inner plate 10 are means for securing it to the outer plate 12. Any appropriate means can be used. The preferred embodiment has a threaded stud 15 welded to the outer side of the inner plate 10. The inner plate 10 further includes a passage 23 to allow a vacuum source to connect to the inside of the cup construction. 
     This vacuum passage 19 passes through the inner plate 10, the sealing member 13, and the outer plate 12. At the outer plate 12 a fitting may be provided to allow attachment of the vacuum source. In one embodiment, the vacuum passage 19 is simply a tube welded over the passage 23 on the inner plate 10 that is threaded so as to accept a vacuum source. A threaded nut 17 may be used for securing the outer plate 12 to the inner plate 10. A vacuum source may then be attached to the end of tube 19. 
     FIG. 3 depicts the outer plate 12. The outer plate 12 like the inner plate 10 is generally planar and made out of a rigid material. Steel or aluminum are generally used, however, this may vary with the application. The effective area of the outer plate 12 must be larger than the effective area of the inner plate 10. The effective area of both plates is that surface area that interacts with the surface of the sealing member 13. This size differential is necessary in order to properly compress the sealing member 13 and create a cup shape with depth 18. 
     The relative size of the outer plate 12 with respect to the sealing member 13 is not a critical factor. The outer plate 12 may be larger than the sealing member 13. However, in the preferred embodiment the effective area of the outer plate 12 is smaller than the sealing member 13. This relationship minimizes the material needed for the outer plate 12 and provides the sealing member 13 clearance to absorb compression when a vacuum is drawn on the cup. 
     The outer plate 12 is equipped with a passage 16 to allow the threaded stud 15 to pass through. The threaded nut 17 may then be threaded on the threaded stud 15. 
     FIG. 4 depicts the sealing member 13. The sealing member 13 is constructed of a compressible, elastomeric soft material. Generally the material used is a closed cell foam rubber. An alternative would be open cell foam rubber, laminated, on at least the sealing side, with a solid rubber surface. The material must be able to sustain a vacuum. Therefore, it must be impermeable to air. In the preferred embodiment the sealing member 13 is supplied with an opposing side 22, also impermeable to air. This allows the sealing member to be reused simply by flipping it and reinserting it between the inner plate 10 and outer plate 12. 
     The sealing member 13 requires no premolding or preforming. In the preferred embodiment the sealing member is flat prior to being compressed. It is not necessary, however, that the sealing member be flat in order for the combination to be operative. The sealing member 13 will be just as effective if it were preformed to allow for a deeper cup. However, preforming the sealing member would likely effect its ability to be reused on the opposing side 22. 
     The compression of the sealing member 13 is demonstrated in FIG. 5. When compressing the sealing member 13 two factors are of importance: first, the sealing member 13 must be compressed enough to allow for formation of the cup with depth 18; second, the integrity of the seal must be maintained. For example, when the sealing member 13 consists of closed cell foam rubber, the compression cannot be so great as to rupture the cells and destroy its ability to hold a vacuum. Generally, when the sealing member 13 is compressed to about 50%-70% of its original thickness both goals can be achieved. A standard cup uses a sealing member 13 about 1 inch thick. However, this dimension may be varied for specific applications. 
     In most applications the sealing member 13 would have a shape generally coincident with that of the inner plate 10, thereby extending equally over all sides of the inner plate 10. However, this is not necessary. In some applications it is desirable to have the extension of the sealing member 13 non-equidistant around the edge of the inner plate 10. In such a case the shape of the sealing members and the inner plate 10 may be significantly different. Such an embodiment is particularly helpful when the surface of the object being attached is not flat, such as the curved surface of a cylinder. 
     The amount of the extension of the sealing member 13 over the inner plate 10 combined with the shape of the object to which the cup is being attached will determine the width of the sealing edge 20. This sealing edge 20 would encompass a portion of the sealing member 13 about the periphery of the inner plate 10. For example, if the extension is great and the cup is being attached to a flat surface, the sealing edge 20 will be broad. In contrast, if the extension is just as great and the cup is being attached to a cylindrical surface the sealing edge 20 along the cylindrical surface would be much more narrow. 
     FIG. 9 illustrates the formation of the sealing edge 20. The extension of the sealing member 13 over the edge of the inner plate 10 interacts with the surface of the object to be attached. When a vacuum is drawn through the vacuum tube 19, the extension of the sealing member 13 is forced against the surface of the object creating the sealing edge 20. 
     FIGS. 6, 7 and 8 demonstrate that the cup may take many different shapes. The most common shapes employed are round, rectangular and oblong. However, if a particular application required a special shape the cup could be so tailored. Indeed, if it were required, the same cup may have a different shape sealing member 13, inner plate 10, and outer plate 12. 
     Depending on the shape of the cup and the need for uniform compression on the sealing member 13, there may be a plurality of threaded studs 15 and a plurality of vacuum passages 19 may be required. Generally, the larger the cup, the greater the need for additional threaded studs 15 and vacuum passages 19. In such a case the sealing member 13, the inner plate 10, and the outer plate 12 would be adapted to allow for passage of the additional studs and passages. Also, the studs and passages may be provided separately rather than integrated as depicted in the preferred embodiments. 
     The above description is illustrative of the present invention and is not intended to limit the invention in spirit or scope. Only the following claims and their equivalents limit the scope of the invention.