Device for covering or displaying an object

Abstract

The device comprises a U-shaped holding device (3) with three limbs, namely a base limb (a), a joining limb (b) and a supporting limb (c) of different dimensions. A wall covering is fixed by means of joining elements (5) or track elements to the front side of the supporting limb (c) in an manner that enables the wall covering to be displaced, and the base limb (a) is mounted on a supporting element (e.g. a wall) by means of connecting elements (6) or track elements of the device in a manner that enables the base limb to be displaced. The corners of the device can be provided with rotating axes whereby permitting a space-saving displacement of the covering. For heavy or large coverings, a number of devices can be coupled to one another by connecting elements. The direction of motion of the device can be freely selected (360°) according to assembly and can be controlled mechanically or in an electronic-hydraulic manner by installing micro-electrical units, if desired, by remote control.

Description

The present invention refers to a device by means of which a flat object attached to the wall, such as an electronic flat screen or a picture, can be covered or intentionally exposed.

High-resolution flat screens for displaying electronically stored information of all kind in public locations, in offices, stations, airports, museums or in business premises as well as in private rooms are very popular nowadays. The distribution of such flat screens has been increasing rapidly. Flat screens of this type provide a favourable picture quality, they are lightweight and they can easily be mounted on a wall or another portable means.

In a sales room or exhibition room, such as a gallery or a museum etc. with a large amount of customers or visitors, such flat screens provide more meaningful and up-to-date information and leave a more permanent impression than printed information material does. Freeze images, video clips or computer animations also enable a dynamic marketing and visual messages whose effect is by far superior to a presentation of mere printed matter.

The large, clear and bright pictures and the wide angle of vision of flat screens ensure an optimum readability and visibility. In conferences or meetings the monitors provide any presentation with a professional touch. Moreover, a flat screen can be mounted to almost any audiovisual device within a few seconds—be this a notebook or a DVD player. Moreover, video conferences can be made more lively, personal and productive when using such monitors. They offer versatile connection alternatives, useful control functions and a conventional, also wireless, remote control.

The high resolution monitors usually have standard width-to-height ratios of 16:9, wherein the diagonal varies, e.g. from 82 cm to 127 cm. Such flat monitors may be hung up the wall either in landscape format or in portrait format or they may be placed at any other position. The format of these screens is in principle not defined. Custom products may have sizes of several square meters. Commercially available, normal models have formats similar to those of oil paintings, graphics, maps etc.

A great advantage of the flat screens is its very flat construction. Modern flat screens are today not wider than 5 to 7 cm. Due to the flat structure, they can be mounted on the wall or other portable objects in a very simple and space-saving manner.

One problem in connection with the use of the monitors is, however, not solved. There are situations in which the electronic messages shall not be shown on the flat screens. Time periods frequently occur during which the electronic screen is not used, is switched off or is disturbing in any other way. Flat screens that are increasingly used for multimedia purposes in a gallery or a museum are disturbing when they are not used next to oil paintings or other pieces of art. In public places such as stations, airports, hotels or stores it regularly occurs that flat screens are not used during a certain period of time. During these “dead times” these screens are often disturbing and they do not match with the overall picture or the atmospheric situation. Flat screens also occupy their space on the wall even in times they are not used and they are normally not dismounted. This wall surface therefore lies idle. In public places this unused surface costs money, which is not economical and not efficient. A flexible use of the wall surface is not possible. The space relations on public walls, in galleries and museums as well as in private living room walls are often limited or shall consciously not look flamboyant. A flat screen or generally a wall panelling such as a wall picture, a painting, photo, poster or hangings of different materials such as fabric, paper, glass wood, plastics, stone needs a certain surface that could also be used by other wall claddings and therefore always competes with alternative hangings and wall covers.

Thus, it is the object of the present invention to provide a device for covering or exposing an object, such as a flat screen, which can be used if needed depending on the situation and in a flexible way.

This object is solved by the subject matters of claims 1, 2, 10 and 14. Preferred embodiments are subject matter of the dependent claims.

The present invention is basically based on the idea that flat screens usually have a sophisticated design but that they are considered to be disturbing after some time due to their fixed attachment on a wall and that they can in the long run not contribute to a high quality room decoration.

Thus, the present invention suggests a technical solution by means of which such a flat screen can be made to disappear from the viewpoint of the observer, namely in that a mechanically and/or electrically movable cover is brought from a position in which it does not cover the flat screen to a position in which the flat screen is fully covered by the cover.

According to a preferred embodiment, the relative movement required for this can be achieved in that the flat screen is moved relative to the cover, i.e. in that the flat screen is moved forward by mechanical and/or electric displacement from the area of a fixedly installed cover.

According to a preferred embodiment, the flat screen used comprises devices provided by the manufacturer, which serve for attachment and for the displaceability of the cover. Particularly, the flat screen may comprise for this purpose pre-mounted rails, which are conveniently integrated into the design of the flat screen so that such portions are not regarded to be disturbing in the state in which the flat screen can be seen. Flat screens that have such accessory means that enable a later attachment of the required construction for displacing the cover, have an especially simple structure in their overall construction, since less parts must be assembled, and the fundamentally carrying construction was already connected to the flat screen by the manufacturer.

The cover is preferably a wall picture, wherein paintings, prints etc. can be used. The use of wall paintings for covering a flat screen leads to an especially aesthetic effect and the integration of the flat screen into an interior is perfectly enabled at a high decorative value.

Depending on the type of aesthetic creation shown on the cover, this cover may in a state in which the flat screen can be seen by the observer deploy an additional aesthetic effect in that the objects that can then commonly be seen mutually supplement one another decoratively. A displacement of the cover downwards may for instance lead to the observer's impression that the cover also forms the column for the flat screen which even increases the aesthetic effect of the flat screen itself.

According to a preferred embodiment, the construction, which enables the relative displacement of the cover with respect to the flat screen, enables a displacement of the wall cover in various directions, preferably in four directions that are orthogonal with respect to each other, to achieve a maximum flexibility for the displacement of the cover. The cover may particularly be displaced into a range that is still free or at which the wall cover acts especially nicely with the decoration, e.g. an oil painting or may thereby again cover an object.

The construction preferably enables a mechanical displacement or a displacement effected by an electromotor. When using an electronic solution, the desired displacement may be achieved by the aid of a remote control or by the aid of switches on the wall.

Such a solution also leads to the fact that a displacement profile can be pre-adjusted so that depending on the user of the room, different displacements must be adjusted and thus a flat screen can be visible or covered. For the case that several flat screens of this kind or other objects shall be covered, the desired covering pattern can be adjusted according to personal taste and can at the same time be changed or retracted at the push of a button.

From the mechanical point of view, the displacement may be achieved by a rigid construction, e.g. by rails in which the cover is displaced. However, more filigree solutions are also suitable, such as rope constructions at which the cover may almost invisibly be displaced. This gives the observer an especially interesting impression, since the cover is moved almost by “ghost hand”. The rope construction is preferably made of transparent threads made of silk or plastics so that this construction does almost not become visible to the naked eye. Metal ropes may also consciously be used to achieve an especially technical impression.

According to a preferred embodiment, the cover may also be part of a piece of furniture, which is built up on a stationary location. The relative movement between the cover and the flat screen is implemented in this case by moving the flat screen out of the piece of furniture by means of a suitable construction. In the simplest case, this might be some sort of telescopic rod which moves the screen from the piece of furniture into the visible area. Preferably, such a construction also allows a turning and/or inclination of the flat screen to ensure an optical viewing angle for the observer. This angular setting as well as the moving-out itself may be controlled by a remote control. Profile settings can also again be made so that fixedly programmed viewing angles can be pre-set according to the present use of the room.

To install a flat screen into such a solution, this flat screen is provided by the manufacturer with respective accessory means, particularly for attachment with a telescopic rod or another carrier, which effects the relative displacement.

According to a further preferred embodiment, the flat screen is already installed into a wall, i.e. it is inserted into a recess of the wall. The flat screen does preferably not project over the plane defined by the wall in this solution. Such a solution allows especially elegant constructions by means of which the cover is moved over the flat screen, since then the cover may directly be guided over the surface of the wall. In the case that the cover is a picture, the observer has the impression after moving the picture of the flat screen that actually a normal picture hangs on the wall. In such a construction, the holder that carries the cover and enables the mechanical and/or electrical displacement of the cover of the screen is attached to the wall and not to the flat screen. Of course, constructions are also conceivable in which the holder is connected to the flat screen, however, the attachment on the wall in this case is preferred differently than in the above-mentioned solutions. In such a solution the total construction always consists of the flat screen, a wall into which the flat screen is sunk and a holder attached to the wall and carrying the cover and which comprises suitable devices which enable a displacement of the cover over the flat screen and out of the area of the flat screen.

According to a further aspect of the present invention, the cover according to the invention is used to selectively expose or cover a painting or other decorative means. According to an especially preferred embodiment, this is again a painting so that a first painting may selectively cover a second, different painting. Such an employment is particularly interesting for galleries that only have a limited exposition area and which are given the opportunity by the present invention to double the amount of works exhibited. By using a suitable control device, which may again be a remote control, the observer may selectively view the one or the other picture. One picture is preferably fixedly connected to the wall and the other one is selectively brought to a position in which it covers or exposes this picture. According to a preferred embodiment, several of such paintings are arranged in stacked fashion so that several paintings may selectively cover a painting fixedly attached to the wall, whereby the exposition surface cannot only be doubled but multiplied many times.

Those paintings that are not currently moved into focus, i.e. which are in a “resting position” may fully disappear behind a cover fixedly connected to the ground, e.g. a wall. The observer does not see that further pictures are available that may be moved to a position of the currently viewed picture. This further cover fixedly connected to the ground may also be designed in the form of a container, into which the pictures that are not shown disappear so that a protective function is also achieved thereby, and according to a preferred embodiment even a security container effect can be achieved in which the pictures that are not shown are fully encapsulated.

Preferred embodiment on how the technical construction may look like that allows the movement of the cover over the flat screen or the movement of a painting over another painting etc. are explained in detail by means of FIG. 1 to 7. The constructive features are not restricted to the respective context but apply analogously to all discussed alternatives of the device according to the invention.

FIG. 1a shows an alternative of a holder in U-shape for assembly of a mechanically or electronically controllable movably supported wall panelling with roller-shaped connection elements towards the wall and towards the panelling;

FIG. 1b shows such a U-shaped holder for assembly of a mechanically or electronically controllable movably supported wall panelling with rail-like connection elements towards the wall and towards the panelling;

FIG. 2a shows a U-shaped, movably supported holder with a movably supported wall panelling fixed to the holder seen from the top in a manner covering a flat screen;

FIG. 2b shows a U-shaped, movably supported holder with a movably supported wall panelling fixed to the holder seen from the side in a manner covering a flat screen, with a possible additional device and a connection portion for heavy panellings;

FIG. 3 shows a movably supported wall panelling fixed to a U-shaped movable holder mounted between the wall and the wall panelling. The wall panelling is located in front of a flat object such as a flat screen in a manner covering same (FIG. 3a) and exposes this object for the observer by lateral displacement of the panelling (FIG. 3b, 3c);

FIG. 4 shows a U-shaped, movably supported holder with a movably supported wall panelling fixed to the holder seen from the top in a manner covering a flat screen (FIG. 4a) and after displacement of the movably supported wall panelling, whereby the flat screen becomes fully visible (FIG. 4b);

FIG. 5 shows an alternative U-shaped holder which is flexible through rotary axes (hinges) with a movably supported wall panelling fixed to the holder seen from the top in a manner covering a flat screen (FIG. 5a), and after moving the movably supported wall panelling and after folding-in the U-shaped holder by means of rotary movements of the two hinges integrated in the holder (FIG. 5b);

FIG. 6 shows two U-shaped, movably supported holders of different dimensions and type of assembly with a movably supported wall panelling fixed to the holders seen from the top in a manner covering a (joint) flat screen;

FIG. 7 shows a schematic view of a U-shaped movably supported holder with an integrated rail module fixed to the wall seen from the side (of FIG. 1b, as an alterative to FIG. 1a).

FIG. 1 shows the device in the form of a U-shaped holder 3 consisting of a base leg a, a connection leg b and a carrier leg c per se, without a wall panelling attached to the front end c and without the wall resting on the base leg a or a stationary means. The device includes as an essential feature this holder in a U-shape with the three legs a, b and c. The length relations of the three legs a, b and c may freely be selected depending on the given proportions of the object to be covered and the wall panelling. Furthermore, the mounting units 5 are shown in the front end of the carrier leg c and 6 on the base leg a of the holder. These mounting units form the connection elements between the wall and the holder and between the holder and the panelling. However, it is not mandatory that the holder is U-shaped. Depending on the circumstances, the holder may also be frame-like, L-shaped or have any other design. An L-shaped alternative is for instance suitable if the displaceable wall panelling itself has a strong frame. In this case the one short leg of the L-shaped holder may be attached at the one frame side so that it stands perpendicularly to the wall, and the other leg is then displaceably supported attached to the wall. The most important purpose of the holder is that it may safely hold the displaceable cover and at the same time enables the lateral displacement of same. For this displacement, rail elements (FIG. 1a) supported on wheels or rollers or slide rail elements (FIG. 1b, 7) may be used or also sliding telescopic elements. It is important that the holder is movably supported and ensures a displacement both on the base leg a as well as on the carrier leg c.

FIG. 2a shows the device with the U-shaped holder 3 from the top, wherein it carries a wall panelling 2 on the front end of the carrier leg c by means of the mounting unit 5, and it is fixed to a wall 1 on the rear side of the base leg a by means of mounting units 6. With its wall panelling the device covers a flat screen 4, which is fixed to the wall 1 via the connection element 7 and the mounting device 8. Caused by the movably supported holder 3 of the device, an object covered in this manner, such as a flat screen 4, may be exposed. FIG. 2b shows the same device from the side. Moreover, it is also useful for very heavy or large wall panellings to reinforce the device and its holder 3 by additional bracings that may be connected through connection elements 15. In FIG. 2b this is shown in dotted lines. The fundamental mechanism is, however, not changed. Instead of moving a picture in front of or away from a flat screen in order to expose same, the flat screen may vice versa also be mounted in a displaceable manner.

FIG. 3a shows the device from the front, wherein it carries a panelling (e.g. a picture) that covers a flat screen. By laterally displacing the movably supported holder of the device and the panelling, the covered object becomes visible and is made usable. FIG. 3c shows a snap-shot during the exposition of the covered flat screen. FIG. 3c shows the fully exposed object. The holder of the device was in this Figure displaced laterally horizontally. However, other directions of movement are fundamentally also possible. The device is not restricted at all to the horizontal direction of movement towards the left or right. The device may also be mounted in a manner that a vertical movement of its holder towards the top or bottom becomes possible. Other directions of movement are also conceivable; basically any direction of movement of the circle (360°) may be realized by the respective assembly.

The movement of the holder of the device for exposing or covering an object shown in FIG. 3 may either be implemented totally mechanically or in an electronically controlled manner. The device may be equipped with miniaturized electromotors that ensure a slow back and forth movement including a final switch-off. Such a motor may directly be connected to the device and its support 3 or it may be integrated into the mounting assembly 5, 13 and 6, 14.

A hydraulic drive of the device is also possible. An electromotor then generates the required hydro-pressure, either instantly when needed or in that it charges a hydro-storage. The movement of the holder is then generated by a hydraulic cylinder-piston unit. Such a means is particularly conceivable for heavy and larger panellings. The automatic controls may additionally be equipped with a remote control unit that allows a convenient control of the device at the push of a button.

FIG. 4a shows the U-shaped holder 3 of the device from the top, wherein it carries a wall panelling 2 on the front end c and is mounted at the base side a to a wall 1 or also to a rail. The device covers a flat screen 4 fixed to the wall 1. Caused by the movably supported holder of the device, an object covered in this manner, e.g. a flat screen, may be exposed. FIG. 4b shows the device from the top after its holder and the panelling mounted thereto have exposed by lateral displacement the object, in this case a flat screen, located behind the panelling.

It is clear that the device and its holder 3 can also be realized in other embodiments. For applications in which a possibly space-saving solution is required, the U-shaped holder may be constructed flexibly and movably by means of rotary axes (hinges 9, 10) integrated on the corners between the legs a and b, and b and c, respectively. FIG. 5a shows such a holder 3 with integrated hinges 9, 10 from the top, wherein the device with its holder carries a panelling that covers a flat screen. In FIG. 5b the device and its holder 3 was moved to the side by the integrated rotary hinges together with the panelling in a very space-saving manner. The movable axes (9, 10) may, if needed, be moved to the desired positions by means of integrated electromotors. The pivoting range of the movable axes (9, 10) may be adjusted by means of opto-electronic or mechanical end portions to rotations of any degrees of rotation. Caused by this flexibility, the panelling comes very close to the wall 1 lying behind the panelling. It is possible to equip rotary hinges with electromotors, whereby these movements can also be carried out automatically by means of a remote control.

FIG. 2 shows 2 U-shaped, flexibly supported and movable holders of devices seen from the top. Both devices are mounted independent of one another, wherein in this example the holder 3₁ of the one device may be moved to the right and the holder 3₂ of the other device may be moved to the left. Both devices are equipped with one movably supported panelling 2₁ and 2₂ each, which cover a common flat screen 4. The Figure elucidates that caused by the individual geometries of the legs a, b and c the device can be used very flexibly for several panellings arranged behind one another.

The device and its holder 3 is installed in that first of all the mounting units 6, 14 are connected to the wall 1 and to the holder 3. This is possible in an easier manner if the object to be covered is taken off. In the normal case, the mounting units 6, 14 are located behind this object and are not always visible from the front. The panelling 2 is connected to the holder 3 of the device by means of the mounting units 5, 13. Depending on the type of wall panelling and its rear side, the contact portions between this rear side and the mounting units 5, 13 may have a different design. If needed, additional electronic or hydraulic components may be mounted to the device in a manner that this device is also located behind the object to be covered. Then, the flat object, such as a flat screen 4, is installed again. The device now allows to cover the object 4 automatically or manually by a respective panelling whose size fits with respect to the object 4 to be covered, or vice versa to expose the object. Caused by the U-shaped geometry of the holder 3 of the device, this device is located behind the object 4 and the panelling and cannot be seen by the observer, neither in the covered nor in the exposed condition of the (flat) object 4.

Thanks to this device it is possible to situationally expose or cover flat objects, such as a flat screen. Usually flat screens are not used around the clock but only during certain periods of time. During the unused time, the flat screen can be covered by a respectively selected panelling by using the device. This may give a room, hall, office etc. a completely different look or different dynamics or a different topic than if the flat screen would hang on the wall in an uncovered manner. Vice versa, the screen can be fetched, if needed, very flexibly and it may practically be used. This fetching may quite well include a surprise effect and may be used respectively. The wall surface used is virtually multiplied by the device in that the flat screen 4 and the panelling(s) 2 need the same surface but this surface can be used situationally in a flexible manner.

It is clear that this device leaves open many technical embodiments. The device may be varied in length, width, depth and geometry of the individual sides as well as in the selection of the material. The device may not only be mounted to a planar wall but also to other carrying elements such as a column. The device and its holder 3 may be equipped with various movable axes (hinges 9, 10). Moreover, very different connection pieces 5, 6, 13, 14 are conceivable, which may additionally be equipped with electronic or hydraulic components to enable an automatic movement of the device and the panelling.

LIST OF REFERENCE NUMERALS

1 wall or other fixed means

2 wall panelling (such as picture, poster, hanging, painting, map)

3 holder (U-shaped carrier) with legs a, b and c

4 flat wall object (such as flat screen)

5 connection elements or mounting units between the device (3) and the wall panelling (2)

6 connection elements or mounting units between the device (3) and the wall (1)

7 connection elements from flat screen (4) to mounting plate (8)

8 mounting device (e.g. plate) for attaching the flat screen (4) on the wall

9 movable axis; hinge

10 movable axis; hinge

11 wall anchor

12 slide or roller rail for the free movability of the device (3) or the wall panelling (2)

13 rail element, integrated into the device (3), movable between (3) and (2)

14 rail element, integrated into the device (3), movable between (3) and (1)

15 connection element that connects two individual devices (3) for heavy panellings (2)

Claims

1. A device for selectively covering a flat screen, comprising

a flat screen,

a cover, and

a means for effecting a relative movement between a cover and the flat screen, wherein the movement is implemented electrically and/or mechanically, and wherein the flat screen is connected to the cover through a construction enabling the relative movement.

2. A device for selectively covering a wall picture, comprising

a first wall picture,

a second wall picture, and

a means for effecting a relative movement between the first wall picture and the second wall picture, wherein the movement is implemented electrically and/or mechanically and wherein the first wall picture is connected to the second wall picture through a construction enabling the relative movement.

3. A device as claimed in claim 1 or 2, wherein the construction for enabling the relative movement basically consists of a rope construction.

4. A device as claimed in claim 1 or 2, characterized in that the construction for enabling the relative movement basically consists of a frame connected to the wall, which allows the displacement of at least one of the two objects relative to the other object.

5. A device as claimed in claim 1, characterized in that the flat screen already comprises elements of the construction caused by the manufacturer.

6. A device as claimed in claim 5, characterized in that the construction for effecting the relative movement between the cover and the flat screen is supported by the flat screen and only the flat screen is connected to the wall.

7. A device as claimed in claim 1, characterized in that the cover carries a wall picture.

8. A device as claimed in one of the preceding claims, characterized in that the relative movement leads to a complete coverage of the one object by the other object and alternatively leads to a complete exposition of the previously covered object.

9. A device as claimed in one of the preceding claims, characterized in that the relative movement is possible along several directions.

10. A piece of furniture comprising a flat screen, wherein the flat screen can be moved out of the upper side of the piece of furniture and as an alternative can fully be moved into the piece of furniture.

11. A piece of furniture as claimed in claim 10, characterized in that the movement of the flat screen is achieved by the aid of a telescopic means.

12. A piece of furniture as claimed in claim 10 or 11, characterized in that in the moved-out state a turning and an inclination of the flat screen is enabled.

13. A piece of furniture as claimed in one of claims 10 to 12, characterized in that moving out the flat screen takes place automatically by switching on the flat screen and a retraction of the flat screen into the piece of furniture takes place automatically when switching off the flat screen.

14. A device for assembling a mechanical or electrically controllable movably supported wall panelling (2) for covering or exposing a background or object (4), consisting of a holder (3) which serves as a central, connecting and movably supported element between the wall panelling (2) and the wall (1).

15. A device for mounting a mechanical or electronically controllable movably supported wall panelling (2) as claimed in claim 14, characterized in that the holder (3) is U-shaped and consists of a base leg (a), a connection leg (b) and a carrier leg (c) wherein on the front side of the carrier leg (c) a wall panelling (2) is movably mountable and the base leg (a) with its back side is movably fixed in the leg direction of the U-shaped holder (3) in a displaceably manner to a supporting element such as a wall (1).

16. A device of a movably supported wall panelling (3) for covering or exposing a background or object (4) according to claim 15, characterized in that the panelling mountable on the front side of the carrier leg (c) is supported with mechanically or electronically controllable motorically drivable connection elements (5) movably on same.

17. A device of a movably supported wall panelling (3) for covering or accentuating a background or object (4) according to claim 15, characterized in that the panelling (2) mountable on the front side of the carrier leg (c) is movably supported with mechanical or electronically controllable motorically drivable slide rail, roller guides or telescoping elements (13).

18. A device of a movably supported wall panelling (3) for covering or exposing a background or object (4) according to claim 15, characterized in that the base leg (a) of the U-shaped holder (3) can be fixed by means of mechanically or electronically controllable motorically drivable connection element (6) in a movably supported manner at a statically carrying element such as a wall (1).

19. A device of a movably supported wall panelling (2) for covering or exposing a background or object (4) as claimed in one of claims 14 to 18, characterized in that the holder (3) of the device includes movable axes in the form of hinges (9, 10).

20. A device of a movably supported wall panelling (3) for covering or exposing a background or object (4) as claimed in one of claims 14 to 19, characterized in that the movable axes (9, 10) are, if needed, controllable by means of integrated electromotors into the desired positions and that the pivot portion of the movable axes (9, 10) can be adjusted by optoelectronic or mechanical limit switches to rotations of any degrees of rotation.

21. A device of a movably supported wall panelling (3) for covering or exposing a background or object (4) as claimed in one of claims 14 to 20, characterized in that the device (3) includes connection elements (15) by means of which several identical devices can be connected to one another so that panellings of heavy materials can also be used.

22. A device of a movably supported wall panelling (3) for covering or exposing a background or object (4) as claimed in one of claims 14 to 21, characterized in that the device (3) can be displaced by means of a hydraulic cylinder piston unit, wherein a hydro-storage exists which can be filled by means of an electronic pump.

23. A device of a movably supported wall panelling (3) for covering or exposing a background or object (4) as claimed in one of claims 14 to 22, characterized in that the electronic control includes a remote control unit for controlling the device at the push of a button.