DE20203140U1 - Frame for a projection surface - Google Patents

Description

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Description Frame for a projection screen

The invention relates to a frame for a projection surface or the like, which has frame parts that grip the front edge of the projection surface.

Mobile projection surfaces are increasingly being used to present products and explain facts, for example at trade fairs, in conference rooms or seminar rooms. Such projection surfaces usually consist of a stable metal frame to which a screen is attached using, for example, snap fasteners. Unfortunately, such a projection surface does not meet higher aesthetic requirements, especially since the fastening elements for the screen are often visible on the front. It is therefore common for a frame to be placed on the edge of the projection surface, which is designed similarly to a picture frame and is therefore correspondingly expensive. However, since projection surfaces come in very different sizes, you have to have a large number of such frames on hand if you want to fit all common sizes with one frame. Carrying such a frame around with you is also annoying, as the frame parts are bulky and easily scratched. On top of that, there is the risk of bringing an unsuitable frame with you.

Especially with large projection surfaces, the screen is often smaller than the area enclosed by the metal frame. This makes it possible to stretch the screen on all sides outwards within the metal frame using rubber bands. In this way,

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However, there is a relatively wide edge with the rubber bands that stretch the canvas, so that a frame covering this must be correspondingly wide and therefore becomes particularly expensive.

The invention is based on the problem of designing a frame of the type mentioned above in such a way that it can be used for projection surfaces of different sizes and takes up as little space as possible.

This problem is solved according to the invention in that the frame has four separate corner pieces which are designed to be fastened to the rear side of a corner of the projection surface in each case, in that each corner piece has a winding body with a band which can be unwound from the winding body and led over the front side of the projection surface along its edge to the opposite corner piece and fastened there.

With such a frame, you can adjust the size of the projection surface by unwinding enough of the bands that serve as the cover parts to cover one edge of the projection surface. The free end of the band is simply attached to the opposite winding body. The winding bodies make it possible to stretch the band so that it is guided tightly over the front of the projection surface. The corner pieces on the back of the projection surface are invisible from the front, so that when the projection surface is in use, only the bands that form the frame are visible.

The fastening of the free end of each band can be done simply by having each corner piece with two winding bodies, with one winding body to one edge of the projection surface and the other winding body to

runs parallel to the other edge of the corner of the projection surface, and that the tape runs from a winding body of one corner piece to a winding body of the opposite corner piece.

Each winding body of each corner piece can carry a sufficient length of tape in the wound-up state to form a frame part even with a large projection surface if, according to an advantageous development of the invention, one winding body is mounted in the corner piece with a small distance to the rear of the projection surface when the corner piece is mounted and the other winding body is mounted crossing over the first winding body with a greater distance to the rear of the projection surface and that the tape is initially wound on the winding body with a greater distance.

Fixing the free end of each band and tensioning the band in the state leading over the projection surface is particularly easy if, according to another development of the invention, the winding bodies each protrude from the corner piece with an adjusting part behind the projection surface and each have a clamping body for fixing the winding body in any position.

The corner pieces are particularly easy to attach to the projection surface if they are designed to be clamped onto a frame holding the projection surface.

The clamping can be carried out by very simple means if the corner pieces are designed to overlap the frame and have a pressure piece on the inside of the frame that can be clamped into the inner corner of the frame.

The cover parts formed by the bands each extend to the outermost edge of the projection surface if the corner pieces are designed to deflect the bands over the respective edge of the projection surface to the respective winding body.

The invention allows for various embodiments. To further clarify its basic principle, one of them is shown in the drawing and is described below. This shows in

Fig.l a view of the back of a projection screen
with the frame according to the invention,

Fig.2 a view of a corner of the projection surface,
seen from the front,

Fig.3 an enlarged view of the back of a
Corner of the projection surface.

Figure 1 shows the back of a projection surface 1, which has a metal frame 2 on which a screen 3 is stretched. A corner piece 4 is attached to the frame 2 at each of the four corners of the projection surface 1. These corner pieces 4 each have two winding bodies 5, 6, which can each be rotated by hand using an adjusting part 7, 8. It can be seen that the winding bodies 5, 6 run a short distance from the edge of the projection surface 1 and cross over each other. The winding body 5 of the corner piece 4 is used to wind and unwind a band 9 shown in Figure 2, which in the unwound state runs from the corner piece 4 along an edge of the projection surface 1. The winding body 6 is used accordingly to wind up a band 10 shown in Figure 2.

The band 9 shown in Figure 2 leads from the winding body 5 outside past the corner piece 4 to the front of the projection surface 1 and then runs along the edge of the projection surface 1 to the corner piece 4a shown in Figure 1. There, the band 9 is again led outside over the corner piece 4a and then reaches the winding body 5a. The band 10 runs accordingly on the front of the projection surface 1 to the winding body 6c of the corner piece 4c.

Figure 3 shows that the corner pieces 4 are each attached to the frame 2 of the projection surface 1. To do this, they grip over the frame 2 in such a way that a pressure piece 11 can be clamped against the inner corner of the frame 2 by means of a clamping screw 12. Figure 3 also shows that the corner piece 4 has two clamping bodies 13, 14 that serve to fix the winding bodies 5, 6. The clamping bodies 13, 14 can be simple screws that are screwed into the corner piece 4 in such a way that their front surface comes into contact with the axis of the respective winding body 5, 6.

List of reference symbols

1 projection screen

2 frames

3 Canvas

4 Corner piece

5 winding bodies

6 winding bodies

7 Control unit

8 Control unit

9 Volumes

10 volumes

Pressure piece clamp screw clamp body clamp body

Claims (7)

1. A frame for a projection surface ( 1 ) or the like, which has frame parts which grip the front edge of the projection surface ( 1 ), characterized in that the frame has four separate corner pieces ( 4 ) which are designed to be fastened to the rear of one corner each of the projection surface ( 1 ), that each corner piece ( 4 ) has a winding body ( 5 ) with a band ( 9 ) which can be unwound from the winding body ( 5 ) and is to be led over the front side of the projection surface ( 1 ) along its edge to the opposite corner piece ( 4a ) and fastened there. 2. A window frame according to claim 1, characterized in that each corner piece ( 4 ) has two winding bodies ( 5 , 6 ), wherein one winding body ( 5 ) runs parallel to one edge of the projection surface ( 1 ) and the other winding body ( 6 ) runs parallel to the other edge of the corner of the projection surface ( 1 ), and that the band leads from a winding body ( 5 ) of a corner piece ( 4 ) to a winding body ( 5a ) of the opposite corner piece ( 4a ). 3. A window frame according to claim 2, characterized in that in each case one winding body ( 6 ) is mounted with a small distance to the rear side of the projection surface ( 1 ) when the corner piece ( 4 ) is mounted and the other winding body ( 5 ) is mounted in the corner piece ( 4 ) crossing over the first winding body ( 6 ) at a greater distance to the rear side of the projection surface ( 1 ), and that the tape ( 9 , 10 ) is initially wound onto the winding body ( 5 ) with a greater distance. 4. A window frame according to at least one of the preceding claims, characterized in that the winding bodies ( 5 , 6 ) each have an adjusting part ( 7 , 8 ) that protrude from the corner piece ( 4 ) behind the projection surface ( 1 ) and each have a clamping body for fixing the winding body ( 5 , 6 ) in any position. 5. A window frame according to at least one of the preceding claims, characterized in that the corner pieces ( 4 ) are designed to be clamped onto a frame ( 2 ) holding the projection surface ( 1 ). 6. A window frame according to claim 5, characterized in that the corner pieces ( 4 ) are designed to overlap the frame ( 2 ) and have on the inside of the frame ( 2 ) a pressure piece ( 11 ) to be clamped into the inner corner of the frame ( 2 ). 7. A window frame according to at least one of the preceding claims, characterized in that the corner pieces ( 4 ) are designed to deflect the strips ( 9 , 10 ) over the respective edge of the projection surface ( 1 ) to the respective winding body ( 5 , 6 ).