JPH0214037Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention includes a screen that is always biased in the winding direction on the winding shaft of the main case that is suspended from the ceiling, and a link-type holding member that connects the screen and the main case. In this device, the screen can be held by this link-type holding member when being pulled down and used, and the screen is automatically rolled up and stored in the main body case by the winding elasticity of the winding shaft. The present invention relates to a screen device for an overhead projector in which a screen bar provided at the lower end of the screen does not collide with the main body case at the end of winding, causing no noise or damage to the members.

The gist of this is that a hydraulic or pneumatic piston-cylinder braking device is linked to a link-type holding member that opens and closes as the screen is pulled down and rolled up. The purpose is to control the operation of the link-type holding member at the time of winding, thereby alleviating the impact at the end of winding.

The details of the screen device for an overhead projector according to the present invention will be explained based on the accompanying drawings. As shown in Fig. 1, this overhead projector screen device has a pair of cylindrical upper parts on a hanging surface 1 of a support fitting C that connects a tilt adjustment part A and a main body case B, which are installed hanging down on the ceiling surface. One ends of the links 2, 2 are opposed to each other and pivoted by a pivot 3, and one end of a pair of similarly cylindrical lower links 4, 4 is attached to the center of the screen bar 6 at the lower end of the screen 5. The other of the upper link 2 and the lower link 4 is pivotally connected to the provided pull fitting 7 in a similar manner, facing each other, and is located on the same side with the upper and lower pivot centers of the upper link 2 and the lower link 4 in between. A link type holding member D is provided by rotatably connecting the ends of the screen 5 using a joint fitting 8.
is pulled down and in use, as shown by the solid line in FIG. When it is rolled up, it is folded as shown by the dot-dash dots in FIG. Further, the braking device E for controlling the operation of the link-type holding member D is composed of a hydraulic or pneumatic piston-cylinder, and is installed at an appropriate location on one of the pair of upper links 2 or lower links 4 of the link-type holding member D. and the internal mechanism is provided on one of the upper link 2 or the lower link 4 in the other of the pair of upper links 2 or lower links 4 via two auxiliary links.
It is linked to parts that are almost opposite to each other.
In the illustrated example, this braking device E is provided near one end of a pair of upper links 2, and one end of an auxiliary link 12 is attached to a rotating shaft 11 of an internal mechanism protruding from one side of the upper link 2. One end of another auxiliary link 14 is rotatably connected to a mounting bracket 13 provided near one end of the other of the auxiliary links 12 and 14, and the other ends of both auxiliary links 12 and 14 are pivotally connected to each other. Accordingly, a pair of upper links 2,2
The braking device E and the two auxiliary links 12 and 14 connect their substantially opposite parts to each other, and the operation of the link-type holding member D accompanying the pulling down and winding up of the screen 5 is controlled by the two auxiliary links 12 and 14.
14 to the internal mechanism of the brake device E. The braking device E includes a piston 16 provided with a rack 18 on the side surface along the movement direction in a hydraulic cylinder 15 or a pneumatic cylinder (not shown), and a coil spring 16.
7 is provided so as to be elastically biased toward one side wall of the cylinder, that is, the left side wall in the case shown in FIG. 19 are engaged. In addition, in the illustrated case, the cylinder 15
A regulating valve 21 for regulating the amount of flowing oil is provided at a suitable location in the oil passage 20 communicating with the inside. This braking device E is installed on the upper link 2 so that the coil spring 17 side is located on the side of the pivot joint between the upper link 2 and the lower link 4, and the moving direction of the piston 16 is along the upper link 2. . In the figure, reference numeral 22 denotes a winding shaft, and the winding shaft 22 is always biased in the winding direction of the screen 5. Further, 23 is a guide fitting for guiding and holding the upper link 2.

Next, the operation of the screen device for an overhead projector according to the present invention will be explained below. First, when the screen 5 in the retracted state shown by the dashed line in FIG. As it rotates in the direction of the arrow in FIG. 3, the rack 18 and pinion 19 engage, causing the piston 16 to slide in the direction of compression of the coil spring 17 while holding it in an upright position as shown by the solid line in FIG. . On the other hand, screen 5
At the time of winding up, the upper link 2 and the downward protrusion 10 of the leaf spring 9 are disengaged by forcibly lifting the screen bar 6 of the screen 5 in the unloaded state shown by the solid line in FIG. Thereafter, the screen 5 is wound up to the state shown by the dashed line in FIG. 1 using the winding and collecting elasticity of the winding shaft 22 as an auxiliary operating force and the restoring elasticity of the coil spring 17 in the braking device E. At this time, in response to the backward movement of the link-type holding member D, the rotating shaft 11 of the braking device E rotates in the direction opposite to the arrow direction shown in FIG. Piston 1 due to the hydraulic pressure of
The restoring speed of the screen bar 6 is slowed down, which slows down the rotational speed of the rotating shaft 11 and the backward movement speed of the upper link 2, that is, the winding and retracting speed of the screen 5, thereby preventing a collision between the screen bar 6 and the main body case B. It softens the impact.

In the overhead projector screen device according to the present invention as described above, a hydraulic or pneumatic piston/cylinder is connected to a link-type holding member D that opens and closes as the screen 5 is pulled down or rolled up. Even with a simple structure in which the braking device E is provided in conjunction with the screen 5, the winding speed of the screen 5 can be moderated, and the impact at the end of winding can be reliably alleviated. Further, by arranging the braking device E so as to be hidden behind the main body case B or the screen 5 when the screen device is being pulled down and used and rolled up and stored, it is possible to eliminate the risk of spoiling the aesthetic appearance of the installed screen device. Furthermore, even in the case of an existing screen device, by easily installing the braking device E and both auxiliary links 12 and 14 at a later date, it is possible to obtain a screen device that can reliably reduce the impact at the end of winding. can.

[Brief explanation of the drawing]

FIG. 1 is a rear view showing an embodiment of the screen device for an overhead projector according to the present invention, FIG. 2 is an enlarged rear view showing the main parts thereof, and FIG. 3 is a sectional view showing the braking device. A: Tilt adjustment unit, B: Main body case, C: Support metal fittings, D: Link type holding member, E: Braking device, 1:
Drooping surface, 2: Upper link, 3: Pivot, 4: Lower link, 5: Screen, 6: Screen bar,
7: Pull metal fitting, 8: Joint metal fitting, 9: Leaf spring, 10: Projection, 1: Rotating shaft, 12: Auxiliary link, 13: Mounting metal fitting, 14: Auxiliary link, 15:
Cylinder, 16: Piston, 17: Coil spring, 18: Rack, 19: Pinion, 20:
Oil passage, 21: Adjustment valve, 22: Winding shaft, 23: Guide fitting.

Claims (1)

[Scope of utility model registration request] A screen 5 is constantly biased in the winding direction on the winding shaft 22 in the main body case B, which is suspended from the ceiling.
The link-type holding member D, which is held in an extended and upright state when it is being pulled down and used, and which is folded when it is rolled up, is connected from a pair of upper links 2, 2 and lower links 4, 4 to the upper links 2, 2. One end is pivotally connected to the main body case B facing each other, and one end of the lower links 4, 4 is pivotally connected oppositely to the screen bar 6 provided at the lower end of the screen 5, and The other ends of the upper link 2 and the lower link 4, which are located on the same side with the upper and lower pivot centers of the upper link 2 and the lower link 4 interposed therebetween, are pivotally connected to each other, and furthermore, a pair of upper links is provided. A piston 16 provided with a rack 18 on the side along the direction of movement in a hydraulic cylinder 15 or a pneumatic cylinder on one of the two or lower links 4 is elastically biased by a coil spring 17 toward one side wall of the cylinder. In addition, the piston 16
A braking device E is provided with a coil spring 17 in which the end of a pinion 19 meshing with a rack 18 provided in
An auxiliary link whose side is located on the pivoting part side of the upper link 2 and lower link 4, and where the piston 16 moves in a direction substantially parallel to the upper link 2 or the lower link 4, and whose one end is attached to the rotating shaft 11. 12
At the other end of an auxiliary link 14, the other end of which is pivoted to a part of the pair of upper links 2 or 4 that is substantially opposite to a braking device E provided on one of the upper links 2 or 4. A pivot-mounted overhead projector screen device.