TECHNICAL FIELD

The present invention relates to a sealing and/or holding device and then more particularly to a sealing and holding device which is intended to be mounted and positioned between a table and a supportive structure.

More specifically, the present invention relates to a sealing and/or holding device to which there can be applied between respective mutually facing surfaces of the table and the supportive structure either a subpressure air flow which will function to hold the table in position relative to the supportive structure or an overpressure air flow which will enable the table to be moved via a generated air cushion, wherein the device is so positioned as to surround a surface area on the table and/or on the supportive structure.

In this case, each sealing and/or holding device includes a first surface part which is intended to face towards and coact with said table surface, and a second opposing surface part which is intended to face towards and coact with the surface on said supportive structure.

DESCRIPTION OF THE BACKGROUND ART

Several different types of sealing and/or holding devices of the aforedefined kind are known to the art.

For instance, European Patent Application, Publication No. EP- A2-0,361,818, teaches a device by means of which a plate is held against a supportive structure with the aid of sub- pressure, wherein a seal defines a space in which the sub- pressure is active.

U.S. Patent Specification 3,693,965 teaches the arrangement

of a groove 16 which opens towards a bed 5 and which encloses a soft seal 17 and an elastic tube 18 which coacts with a source of overpressure through the medium of a connection 19. The seal 17 is pressed against the bed 5 by the pressure generated in the elastic tube or hose 18 when lifting the table 1.

The present invention is concerned particularly with a sealing and/or holding device which is intended to be used with such tables as those where the table top is supported by a support¬ ive structure and where the table top can be lifted slightly through the medium of an overpressure-generated air cushion so as to enable the table top to be moved readily along the supportive structure on the air cushion, and wherein the table top can be held and clamped in a predetermined position relative to the supportive structure with the aid of subpres- sure.

An arrangement of this kind is illustrated and described in U.S. Patent Specification 4,190,240.

The inventive device is particularly intended for use in an arrangement of the kind illustrated and described in a Swedish Patent Application 93 03008-8 entitled "A Table Arrangement" and filed at the same time as the instant application by the same Applicant.

Reference is also made in this regard to the content of International Patent Application No. PCT/SE93/00980.

SUMMARY OF THE INVENTION

TECHNICAL PROBLEMS

When considering the earlier known state of the art, as described above, with regard to the different forms and configurations of sealing and/or holding devices and while

taking into account the specific application of the invention in which a table or table top can be held firmly in relation to a supportive structure by applying a subpressure or in which a table or table top can be moved easily over the supportive structure on an overpressure-generated air cushion, it will be seen that a technical problem resides in the ability to provide a sealing and/or holding device whose form and construction will enhance the frictional and clamping effect between table top and supportive structure when a subpressure is applied, so that the table top will be held stable in relation to the supportive structure by virtue of the sealing device, as a result of forced expanding movement of the sealing device.

It will also be seen that a technical problem resides in realizing that the two surface parts of the device shall in cross-section diverge in a direction away from a surface area that is included and formed by the device.

Another technical problem is one of realizing that at least one of the surfaces, either the surface belonging to the table top or the surface belonging to the supportive structure shall be provided with a recess, this recess also diverging in one cross-section in a direction away from said surface area.

It will also be seen that a technical problem is one of realizing the significance of positioning one of said surface parts parallel with the surface that belongs to the table top and therewith provide a relatively large surface expansion and a large frictional surface.

It will also be seen that a technical problem is one of realizing the significance of choosing a convenient angle between the two surface parts that diverge in cross-section, this angle being chosen in accordance with the field of application and the elasticity and surface structure of the surfaces of the sealing device.

Another technical problem resides in realizing the signifi¬ cance of constructing the sealing and/or holding device from an appropriate material, preferably from polyurethane, rubber or some similar material having a Shore hardness in the order of 70 Shore, at least in the surface layer.

Another technical problem is one of realizing the significance of providing at least one surface of the sealing and/or holding device, preferably a flat surface, with a structure which will induce or generate a high frictional force, and that at least the flat surface which faces towards the flat undersurface of the table top shall have a similar structure.

Another technical problem resides in realizing the signifi- cance of providing the supportive structure with a groove which corresponds to the divergence of one surface part from a flat surface and which is as large as or possibly slightly larger than the sealing and/or holding device used.

SOLUTION

The object of the present invention is to provide a solution to one or more of the aforesaid technical problems and takes its starting point from a sealing and/or holding device which can be fitted between a table top and a supportive structure, wherein there can be applied between mutually facing surfaces of the table top and the supportive structure a first air flow or air stream which functions to generate a subpressure and therewith hold the table top in a given position relative to the supportive structure, or a second air flow or air stream which functions to generate an overpressure and therewith enable the table top to be moved relative to the supportive structure through the medium of a generated air cushion, and wherein the inventive device is positioned to surround a surface area of the table top and/or the supportive structure, and wherein a first surface part is intended to face towards and coact with the bottom surface of the table top and a

second surface part is intended to face towards and coact with the upper surface of the supportive structure.

It is proposed in accordance with the invention that in the case of a sealing and/or holding device which is intended for use in the aforesaid technical field or for the aforesaid technical application the two surface parts will diverge in cross-section away from or towards said surface area, and that at least one of the surfaces belonging to the table top or to the supportive structure include a recess which in cross section diverges in a direction away from or towards said surface area, in a similar or generally similar manner.

According to proposed embodiments which lie within the scope of the inventive concept, one of said surface parts is positioned parallel with the bottom, flat surface of the table top.

It is also proposed that the diverging angle is between 30° and 5°, preferably between 15° and 20°.

According to one embodiment of the invention, the sealing device or at least the surface area adjacent one or both of said surface parts is comprised of an elastic material having a Shore hardness of 40-80 Shore, said material conveniently being polyurethane, rubber or a like material having a well- adapted elasticity.

It is particularly proposed in accordance with the invention that at least one surface part has a rough surface structure which will intentionally generate a high coefficient of friction with an engaging surface, and it is also proposed that at least the outer part that faces towards the bottom flat surface of the table top shall also include a similar surface structure.

Finally, it is proposed that there is provided solely in the

supportive structure a groove which in cross-section corres¬ ponds to the divergence of said outer parts and which is intended to coact with and to enclose the sealing and/or holding device.

ADVANTAGES

Those advantages primarily afforded by an inventive sealing and/or holding device when used within the aforesaid technical field reside in the provision of means which as a result of the configuration of the sealing device, the holding effect generated thereby and the possibility of its movement when holding the table top, will create conditions for the satis¬ factory and stable holding of the table top against the supportive structure with the aid of a subpressure. Another advantage resides in the ability to move the table top relative to the supportive structure over an air cushion formed beneath the table top.

The primarily characteristic features of an inventive sealing and/or holding device are set forth in the characterizing clause of the following Claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred exemplifying embodiment of an inventive sealing and/or holding device will now be described in more detail with reference to the accompanying drawing, which illustrates a flat table top and a supportive structure in different positions, with the intermediate sealing and/or holding device also being shown in different positions, wherein more specifi¬ cally

Figure 1 illustrates the position of the inventive device when the table top rests under its own weight directly on the device and where the device is supported by the supportive structure;

Figure 2 illustrates the position of the device when the table top is held against the supportive structure with the aid of subpressure; and

Figure 3 illustrates the position of the device in relation to the supportive structure when the table top rests on an air cushion and is therewith spaced above the inventive device.

DESCRIPTION OF EMBODIMENTS AT PRESENT PREFERRED

The invention relates, among other things, to the shape or configuration (primarily the cross-sectional shape) of the sealing and/or holding device, and also the shape or configu- ration of a groove formed in the bottom surface of the table top and/or in the upper surface of the supportive structure, and is used in the manner described in the introduction.

The device 1 can be fitted between a table top 2 and a supportive structure 3, where the space accommodating the device? is delimited by a flat bottom surface 2a of the table top 2 that faces towards the supportive structure 3 and a flat upper surface 3a of the supportive structure 3 that faces towards said bottom surface of the table top, wherein a first subpressure-generating air flow can be applied to the inven¬ tive device through the medium of a line or hose connection 4 and through the medium of channels 5 provided in the upper surface 3a of the supportive structure such as to hold the table top 1 in a given position relative to the supportive structure 3, as illustrated in Figure 2, or wherein there can be applied a second, overpressure-generating air flow which is effective in forming an air cushion between the surfaces

2a and 3a, as shown in Figure 3, so as to enable the table top 2 to be moved easily relative to the supportive structure 3.

The sealing device 1 is positioned to surround a surface area "A" of the table top and/or supportive structure, and if it is assumed that the sealing device is circular and positioned in a circular groove, said surface area will be defined by a circular peripheral line 2a ⁷ .

Sealing and holding devices of the kind meant here include a first surface part la which is intended to face towards and to coact with a flat circular surface segment 2a" on the table top, and a second surface part lb which is intended to face towards and to coact with a sloping or inclined circular surface segment 3a" on the supportive structure.

Figure 1 shows the two surface parts la, lb diverging in cross-section away from said surface area "A" defined by the circular line 2a'. At least one of the surfaces, either the surface (not shown) on the table top or the surface on the supportive structure is provided with a circular recess or groove 6 which has a surface part 6a (corresponding to the surface segment 3a") which in cross-section diverges in a direction away from said surface area "A".

As will be understood, this divergence may alternatively be towards the surface area "A".

According to the illustrated embodiment, one of the surface parts, in this case the surface part la, is positioned parallel with a flat surface segment 2a' of the table top, this surface segment forming an extension of the surface 2a.

The divergent angle "a" is between 30° and 5°, preferably between 15° and 20°, and in the illustrated case is 18°.

The inventive device 1 is made from an elastic or resilient

material, preferably a material having a Shore hardness of 40- 80 Shore, particularly a hardness of about 75 Shore, and will preferably be polyurethane, rubber or a similar material.

The modulus of elasticity will preferably be between 500 and 900%.

At least one surface, in this case the surface la, will include a structure which will purposely generate a high frictional force, for instance a structure corresponding to the structure of a grade 3 sandpaper.

Since it shall be possible for the other surface lb to slide along the surface 6a or the surface segment 3a", the second surface lb will be far smoother than the surface la.

In the case of the exemplifying embodiment illustrated in Figures 1-3, only the supportive structure 3 is provided with a groove 6 that corresponds to the divergence of the surface parts, while the device 1 can be fully enclosed in the groove 6 in a slightly expanded state.

Figure 1 shows the sealing device 1 in a position in which the table top 2 rests under its own weight against the device 1, which is supported by the supportive structure 3 and its groove 6 and the surface 6a. There is therewith formed between the surfaces 2a and 3a a closed space 10 which has an exten¬ sion egual to the extension of the surface area "A".

It will be observed that in the initial position of the device 1 in the groove 6, in which position the surface 2a (and the surface segment 2a") is spaced from the surface 3a by a distance "dl", and also in which the device 1 is located in the groove 6 such that one end surface lc of the device will be located at a distance from one end surface 6b of the groove 6.

When a subpressure is generated in the line 4 and the channels 5, the table top 2 will be drawn down against the supportive structure 3 such as to leave only a very small space 10', as shown in Figure 2.

As the device 1 is forced or pulled down towards the support¬ ive structure, the device will slide down the inclined surface 6a of the groove along the surface part 3a" or 6a in the direction of the arrow shown through a "horizontal" distance "d2" with a corresponding linear movement of the surface la along the surface segment 2a", which can be assumed to hold the table top 2 firmly in relation to the supportive structure 3 more effectively than would a metal-on-metal contact.

The distance between the surfaces 2a and 3a is extremely small and the invention is based on the conception that these surfaces will not lie in contact with one another.

When the space 10 in Figure 1 is subjected to an overpressure, through the line 4 and the channels 5, such as to form a larger space 10" or an air cushion according to Figure 3, an air flow is able to pass through the passageway 11 between the outer segment 2a" and the outer part la of the sealing device 1. Since the surface la has a rough, friction-inducing structure, such as a sandpaper structure, the airflow through the passageway 11 will become turbulent and therewith contrib¬ ute in maintaining the pressure in the space 10" with a smaller passageway 11, therewith creating conditions by means of which the table top 2 is able to move in relation to the supportive structure 3 in a simple fashion and with the aid of a narrower air passageway 11 than that which would apply in the absence of a rough surface structure.

Should the sealing device 1 be expanded slightly by the overpressure prevailing in the space 10" and therewith move slightly to the left in Figure 3, only the surfaces 2a and 3a will be located closer together than what is shown in Figure

It is also feasible to provide the groove 6 with radially extending recesses and to provide the sealing device with corresponding radially extending ribs so as to further limit rotary movement of the table and therewith form rotation inhibiting means.

The sealing device 1 of the illustrated exemplifying embodi- ment is constructed from an homogenous material.

It lies within the scope of the invention for the surface layers la' and lb' of the surfaces la and lb to be softer than a core 1 ' .

In this regard, the core may be made from a material having a hardness above 70 Shore, for instance a hardness of 80-85 Shore.

The surface layers la' and lb' will preferably have a hardness which when the sealing device is fitted will effectively seal against respective surfaces in the presence of a subpressure.

It will be understood that the invention is not restricted to the aforedescribed and illustrated exemplifying embodiments thereof and that modifications can be made within the scope of the inventive concept as defined in the following Claims.