EP2286692A1

EP2286692A1 - Device for height adjustment of a whiteboard

Info

Publication number: EP2286692A1
Application number: EP09168197A
Authority: EP
Inventors: Robert Schaefer
Original assignee: Smit visual supplies BV
Current assignee: Smit visual supplies BV
Priority date: 2009-08-19
Filing date: 2009-08-19
Publication date: 2011-02-23
Also published as: DE202009016122U1

Abstract

The invention relates to a device for height adjustment of a board, like an interactive whiteboard, the device comprising:
- a stationary first frame;
- a second frame linear and parallel movable arranged to the stationary first frame;
- at least two vertical guide rails with carriages running in the guide rails arranged between the stationary first frame and second movable frame;
- a spring for compensating the weight of at least the frame, such that the second frame can be positioned at any position relative to the first frame.

Description

The invention relates to a device for height adjustment of a board, like an interactive whiteboard.
Such height adjustment devices have been used for a long time and originate from the era of blackboards. These blackboards were used for example in school classes where a teacher could write with a crayon onto the blackboard. In order to be able to adjust the height of these blackboards, a device is known in the prior art using contra weights. With this device the blackboard is arranged on a movable frame, which frame is suspended on cables running over wheels and which comprise on the other end a contra weight to equalize the weight of the blackboard and make it possible to position the blackboard at any desired height. The movable frame is typically guided along rods. To this end, bushings are arranged to the movable frame and rods, over which the bushings can slide, are arranged stationary to for example a wall.
Another known prior art device for adjusting the height of a blackboard uses springs instead of contra weights. In this device springs are arranged in a stationary frame. A second frame is movable along the stationary frame and carries the blackboard. The springs extend between this stationary frame and movable second frame with the help of some cables and wheels.
Blackboards are more and more replaced by interactive whiteboards. These interactive whiteboards have a projection device which is typically suspended in front of the whiteboard to project for example a computer image on the whiteboard. Some kind of pointer device is furthermore provided, which acts as a mouse for controlling the computer. As a result, the whiteboard becomes a digital blackboard with the advantages and capabilities of a computer.
In order to be able to adjust the height of such an interactive whiteboard, prior art devices as described above are used. However, instead of only having to adjust the height of the whiteboard, also the projection device has to be moved up and down. This projection device is not positioned in the same plane as the whiteboard, but suspended in front of the whiteboard, typically at a distance of 1 or 2 meters. This distance together with the weight of the projection device results in a substantial torque on the height adjustment frame. As the prior art devices are all designed for height adjustment of a board without a substantial torque, using such prior art devices for an interactive whiteboard results in increased wear and / or poor operation of the height adjustment device.
For example the guiding of the movable frame along rods with bushings cannot take the torque as the necessary play between the rods and bushings is such that as a result of the torque, the bushings will get jammed on the rod preventing simple height adjustment.
It is therefore an object of the invention to reduce the above disadvantages and to provide a device for reliable height adjustment of an interactive whiteboard.
This object is achieved by a device according to the invention, which device comprises:

a stationary first frame;
a second frame, linear and parallel movable arranged to the stationary first frame;
at least two vertical guide rails with carriages running in the guide rails arranged between the stationary first frame and second movable frame;
a spring for compensating the weight of at least the frame, such that the second frame can be positioned at any position relative to the first frame.

By providing guide rails with carriages, the device can easily take up the torque resulting from a suspended projection device. With the provided spring in the device according to the invention, the additional weight of the projection device can easily be compensated for. If contra weights would be used, the size of the weights would be such, that handling, moving or shipping such a device would no longer be easy and cost effective.
In a preferred device according to the invention, the cross section of the guide rails is C-shaped. The C-shaped cross section prevents the carriages from running out of the guide rails when the device is unevenly loaded. Preferably, the carriages comprise wheels, which wheels run in the C-shaped guide rails. These wheels ride on the inner surface of the C-shaped guide rails and can support substantial tangential forces, which can counteract the torque resulting from a suspended projection device.
In another embodiment of the device according to the invention the wheels are offset. This means that the wheels are not arranged in a single plane. This improves the stability of a carriage and the capability to take up disturbing forces from unevenly loading the adjustment device of the invention.
In yet another embodiment of the device according to the invention the spring is arranged between the stationary first frame and the bottom of the movable second frame.
In a preferred embodiment of the device according to the invention the spring is arranged horizontal and with one end to the first frame and wherein a cable is arranged to the other end of the spring and the cable is guided along a wheel to the bottom of the second frame. This provides for a compact solution, which enables a large stroke of the movable frame and thus a large range of possible height positions of a board.
In still another embodiment of the device according to the invention, the device comprises a sub frame mounted to the movable second frame, which sub frame extends over the top of the second frame. A projection device can be mounted on the sub frame. When the movable frame is adjusted, the sub frame is automatically taken along, such that a projected image will stay within the boundaries of the whiteboard.
In yet another preferred embodiment of the device according to the invention, the device comprises a support arranged to the stationary first frame to support the device on a base.
The invention also relates to a combination of a device according to the invention, a whiteboard arranged on the movable second frame and a projection device for projecting an image on the whiteboard.
In a preferred embodiment of the combination according to the invention the projection device is arranged to the sub frame.
These and other advantages of the invention will be elucidated in conjunction with the accompanying drawings.

Figure 1 shows a perspective view of an embodiment of a combination according to the invention.
Figure 2 shows the embodiment of figure 1 with the whiteboard and projection device removed.
Figure 3 shows an enlarged view of part of figure 2.

In figure 1 an embodiment 1 of the invention is shown. This embodiment 1 has two supports 2 on which the stationary frame 3 is mounted (see figure 2). The whiteboard 4 of the embodiment 1 has two side panels 5, which are hingedly arranged to the center part 6. Underneath the whiteboard 4 a gutter 7 is arranged for storing markers and a wiper.
A sub frame 8 extends above the whiteboard 4. A projection device 9 is suspended from this sub frame 8, such that the projection device 9 is in front of the whiteboard 4 and can project an image on the whiteboard.
In figure 2 the whiteboard 4 has been removed. The stationary frame 3 is mounted on the supports 2. At both sides of the stationary frame 3 rollers 10 are mounted, which rollers form carriages. These rollers 10 run in vertical guide rails 11, which are mounted on a second movable frame 12 (See also figure 3). As a result the movable frame 12 can be moved up and down relative to the stationary frame 3. The sub frame 8 and whiteboard are mounted to this movable frame 12, such that the whiteboard can be moved up and down together with the projection device 9.
The guide rails 11 have a C-shaped cross-section. This has the advantage that the rollers 10 are enveloped by the C-shaped structure preventing the rollers 10 from derailing.
The embodiment 1 further has two springs 13 for compensating the weight of the whiteboard 4, the projection device 8, the movable frame 12 and the sub frame 8. These springs 13 are arranged with one end to a threaded rod 14, which is mounted to the stationary frame 3. The other end of the springs 13 is connected via a piece of cable 15 to a rotatable wheel 16. To this wheel 16 two pieces of cable 17, 18 are connected, which pieces 17, 18 are each mounted to a side of the movable frame 12. This has the advantage that the compensating force of the springs 13 is equally distributed over the movable frame 12.
The threaded rod 14 can be used to adjust the pretension of the springs 13, such that the whiteboard 4 and projection device 9 can be balanced.
By using the wheels 10 running in the C-shaped guide rails 11, the torque resulting from the suspended projection device 9 can easily be taken up. With the provided springs 13 the additional weight of the projection device 9 can easily be compensated for, while providing an easy to handle interactive whiteboard 1.

Claims

Device for height adjustment of a board, like an interactive whiteboard, the device comprising:
- a stationary first frame;

- a second frame linear and parallel movable arranged to the stationary first frame;

- at least two vertical guide rails with carriages running in the guide rails arranged between the stationary first frame and second movable frame;

- a spring for compensating the weight of at least the frame, such that the second frame can be positioned at any position relative to the first frame.
Device according to claim 1, wherein the cross section of the guide rails is C-shaped.
Device according to claim 1 or 2, wherein the carriages comprise wheels, which wheels run in the C-shaped guide rails.
Device according to claim 3, wherein the wheels are offset.
Device according to any of the preceding claims, wherein the spring is arranged between the stationary first frame and the bottom of the movable second frame.
Device according to claim 5, wherein the spring is arranged horizontal and with one end to the first frame and wherein a cable is arranged to the other end of the spring and the cable is guided along a wheel to the bottom of the second frame.
Device according to any of the preceding claims, comprising a sub frame mounted to the movable second frame, which sub frame extends over the top of the second frame.
Device according to any of the preceding claims, comprising a support arranged to the stationary first frame to support the device on a base.
Combination of a device according to any of the preceding claims, a whiteboard arranged on the movable second frame and a projection device for projecting an image on the whiteboard.
Combination according to claim 7 and claim 9, wherein the projection device is arranged to the sub frame.