Bellows with molded panels

A multi-sided bellows cover has panel sections formed of extruded plastic panels in which rigid wall sections are connected at the fold lines by flexible web sections. The web sections are integrally molded by extrusion with at least one adjacent wall section, and many serial wall sections alternating with web sections may be integrally co-extruded with one another. Intermittently, a bead of one of the flexible web sections of one of the panel sections is captured in a slot of one of the rigid wall sections of another panel section.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH/DEVELOPMENT

Not applicable.

FIELD OF THE INVENTION

This invention relates to multi-sided bellows covers of the type which extend between relatively movable parts of a machine to which the bellows is mounted.

BACKGROUND OF THE INVENTION

Bellows are well known in industrial and other applications to enclose the space between two relatively movable parts of a machine. One such application is a lift table of the type that has a scissors or other lift mechanism to lift a table relative to a base. One end of the bellows is connected to one of the relatively movable parts of the machine, for example in a lift table to the table, and the other end of the bellows is connected to the other relatively movable portion, for example the base in a lift table, and the bellows encloses the machine between the two portions, i.e. between the base and the table in a lift table, typically where the mechanism resides. The bellows encloses this to protect it from dirt, coolants, cutting fluids, light, humidity and so forth.

Bellows have typically been made by providing accordion folded or sewn panels, made of for example rubberized or vinyl coated canvas or other fabric strips joined edge to edge to form the pleats of the panel, and connecting adjacent panels at the corners with flexible or foldable fabric which encloses the corners. As such, the bellows has a typically four-sided pleated construction. While a bellows must be expandable and contractible to enclose an axially variable space, a bellows must also provide resistance to lateral forces which may be exerted against the sides of the bellows to protect the enclosed space. The bellows must do this when it is both extended and retracted, and at all the positions in between.

The individual slats which make up the pleats of a bellows have typically been joined at their longitudinal edges either by bonding to a continuous sheet of flexible material and folding, by sewing or by a similar operation. The material of the bellows at the edges of the individual slats, i.e., at the apexes of the pleats, must be sufficiently flexible to permit expansion and contraction of the pleats as the bellows expands and contracts. However, the slats must also be rigid enough to support the weight of the bellows without sagging and to resist lateral forces which tend to deflect the bellows in the lateral direction perpendicular to the axial direction, which is the direction of expansion and contraction. The result in many of the prior art bellows has been to make the bellows of multi layer constructions, including flexible layers and rigid layers, or to re-enforce the bellows with wires or rigid panel components, resulting in expensive fabrication operations and considerable weight of the bellows.

SUMMARY OF THE INVENTION

The present invention provides a multi-sided bellows cover of the above-described type in which each panel includes a number of relatively rigid wall sections spaced apart by a number of web sections which are flexible relative to the wall sections, each web section being integrally molded with a longitudinal edge of at least one wall section. Therefore, the wall sections provide the needed rigidity, and the web sections provide the needed flexibility at the apexes of the pleats. As used herein, “molded” is meant to include extruded, injection molded, vacuum formed, press molded, blow molded or any other molding process.

In a preferred aspect, the wall sections and integral web section are extruded profiles, meaning that they are continuous for the length of the sections. In an especially preferred aspect, at least some of the web sections and adjacent wall sections are connected by a bead-in-slot connection. Therefore, these sections can be disconnected relative to one another. In a different aspect the web sections and adjacent wall sections can be integrally molded to provide a plurality of web sections and wall sections in one piece.

Bellows of the invention have their adjacent panels connected by corner sections, which can be a flexible piece of sheet material folded so as to provide the corner. The corner may be either a square corner or a chamfered comer, as is ordinary in other types of bellows. Bellows of the invention may also have a strap connected from peak to peak of the pleats to limit the extension of the bellows.

These and other objects and advantages of the invention will be apparent from the detailed description and drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIGS. 1-4, a bellows cover10of the invention has four sides12,14,16and18which define an open-ended box like structure with accordion folded, or pleated, sides. The adjacent sides,12,14,16and18are connected to one another at their ends, i.e., at the comers of the bellows10, by strips of folded fabric or other flexible sheet material20. The sheet material20may be provided both on the inside and on the outside surfaces of the sides12,14,16and18. In addition, the apexes of the pleats may be connected by limiting straps22(FIG.4), as required (for example, two) on each side, on the inside of the bellows10. The limiting strips22may be adhered to the peaks, or maybe affixed by stitching, stapling, rivets or other mechanical fasteners. In this context, mechanical fasteners should be interpreted to include adhesives, as well as other types of mechanical fasteners such as stitching, staples, rivets, bolts, screws, heat sealing or other means by which two components are secured.

FIG. 1Aillustrates one possible end mounting configuration for the bellows10. The top slat23is axially directed and affixed by bolts, rivets, adhesive or other fasteners to the table25or other relatively movable component of the machine to which the bellows is assembled, and the bottom slat27is laterally directed and affixed by bolts, rivets, adhesive or other fasteners to the base29or other relatively movable component of the machine to which the bellows is assembled. Alternatively, both top and bottom slats may be axially directed or laterally directed, or any combination. Any suitable mounting configuration may be used with the invention, and it need not necessarily be a molded slat which is attached directly to the movable component. For example, an end slat of the bellows could be affixed to an adaptor array, such as loops of material supported on a bar, which is attached to the movable component.

Referring toFIGS. 5-8,FIGS. 5 and 6illustrate a square corner construction andFIGS. 7 and 8illustrate a chamfered corner construction. Both of these corner constructions have been applied to bellows in the prior art, and can also be applied to a bellows of the invention. Referring toFIGS. 9 and 10, sides16and18are shown laid flat, andFIG. 10illustrates one of the corner pieces20below the sides16,18, in position for fixation to the sides16,18. End26of panel18is cut straight and end28of panel16is cut in zig zag fashion with the peaks and valleys of the zig zag corresponding to fold lines of the panel16, which fold lines line up with fold lines of the panel18. A small minimum spacing, for example one-quarter inch, is provided between the end26and the end28. Fabric panel20, for example vinyl coated canvas or other fabric, is stitched, heat sealed, adhered, RF sealed, sonic welded or otherwise secured to the facing sides of the panels16and18, and a panel20may be provided on each side of the panels16and18. The assembly is then folded so as to form the pleats, and how it is folded determines whether the comer is square as shown inFIGS. 5 and 6or chamfered as shown inFIGS. 7 and 8. As shown inFIG. 5, if the peaks on one side are made to correspond with the peaks on the other side, then the corner appears square in top view. However, if the valleys on one side are made to correspond to the peaks on the other side, then the comer appears chamfered as shown inFIG. 8in top view. Note that inFIG. 10, the straight side26could have also been cut in zig zag fashion so as to fill in the v-shaped gaps between the straight side26and the valleys at the end of side28. In addition, both sides26and28could have been cut straight as well, in which case the panels16and18would be spaced further apart than as shown in FIG.10.

Referring toFIGS. 11 and 12, a section of a panel12,14,16or18is shown. Each panel12,14,16and18includes a number of edge to edge connected panel sections30, each of which has a relatively rigid wall section32integrally connected along one edge to a relatively flexible web section34. The web sections34form the folds which are the peaks and valleys of the accordion folded panel. The wall sections and web sections are integrally molded so that at least one web section is integral along a longitudinal edge of at least one web section. The plastic of the wall sections32is harder and more rigid than the plastic of the web sections34. For example, the wall sections32may be molded by extrusion of rigid PVC and the web sections34may be similarly and simultaneously molded by extrusion of flexible PVC, in one piece with the rigid PVC wall sections32. Other materials may also be used for molding the panel such as polystyrene, polyethylene, polypropylene or other plastic materials. In some cases, the softer web sections are made softer either with an additive or by making them thinner, or making them of a different material than the wall section, for example, urethane. In any event, each panel section will typically be an extruded section, since it is longitudinally consistent, i.e., its lateral cross section is the same for the entire length of the section. As such, the panel sections can be made quite long, using the same extrusion dies.

As shown best inFIG. 12, a longitudinally extending bead36is provided at the free longitudinal edge of the web34. The bead36is received in a longitudinally extending slot38at the free longitudinal edge of the wall section32of the adjacent panel section30, the slot38being open on its side opposite from the main portion of the wall section32of the adjacent panel section30. Thus, the web34can be slipped into the opening of the slot38, with the bead36captured within the slot38.

Molded wall and web sections as shown inFIGS. 11 and 12are known and heretofore have been used for making accordion-folded folding doors. Such materials are available in many hardware or home improvement stores.

FIGS. 13 and 14illustrate an alternative construction of the panel sections30. The construction ofFIGS. 13 and 14is essentially the same as that ofFIGS. 11 and 12, except the panel sections39have multiple rigid wall sections32that are integrally connected with multiple flexible web sections34. In the embodiment ofFIG. 13, four wall sections32are integrally connected by four web sections34in each panel section39. It is noted that in the embodiment ofFIG. 11, each fold of the pleated panel section is supported by two enlarged sections, one being the enlarged section which defines the slot38and another being an enlarged section40which is solid and integrally molded with the adjacent wall section32and web sections34. These sections provide stiffening at the folds. In the embodiment ofFIG. 13, only one enlarged section, either the enlarged section which defines the slot38, or the enlarged solid section40, is provided adjacent to each fold of the pleated panel section39.

Preferred embodiments of the invention have been described in considerable detail. Many modifications and variations to the preferred embodiments described will be apparent to those skilled in the art. For example, any number of rigid wall sections32and flexible web sections34could be co-extruded in one piece. Therefore, the invention should not be limited to the embodiments described, but should be defined by the claims which follow.