JP5745819B2 - Braking device for vertical blackboard - Google Patents

Description

  The present invention relates to a device for braking a vertically moving blackboard in a vertical blackboard, which eliminates unpleasant noise caused by the vertical blackboard colliding with an upper frame or a lower frame, and A braking device for a vertical blackboard that can eliminate the risk of injury by pinching a hand between the blackboard and the lower frame.

  The vertical blackboard refers to a blackboard in which two blackboards can be moved up and down to use each board surface alternately. The top and bottom blackboard itself is widely used in lectures, science rooms, music rooms, cooking training rooms, etc. that can accommodate a large number of people, mainly in the field of education. Since the board surface written down can be slid upward and lifted, it is easy for students sitting behind the classroom to see the written contents. In addition, the two blackboards can be rotated, so the progress of the lecture is less affected by the speed of the students' writing.

Utility Model Registration No. 3080564 JP-A-8-72483

  The basic structure of the vertical blackboard appears in the above patent document. The writable part of the blackboard is divided into two upper and lower isoforms, an equal area, and an equal mass area. The first region is located closer to the writer and is called the front surface. The second area is located behind the first area and is called a rear surface. The upper corners of the front and rear surfaces are joined by a wire. The front and rear surfaces are suspended by this wire and supported by a fixed pulley fixed in the vicinity of the upper frame. The length of the wire must be at least the vertical dimension of each writing surface. In place of a wire and a pulley, a chain and a sprocket are used to improve power transmission efficiency.

  The home position of the top / bottom blackboard is such that the front is at the bottom and the back is at the top, both showing the writer the entire board. If the front position is pushed up from the home position, the rear surface will be lowered at the same time, and the front surface will reach the upper frame and the rear surface will reach the lower frame and stop. If the front surface is pulled down, the rear surface simultaneously rises, the front surface reaches the lower frame, the rear surface reaches the upper frame, and returns to the home position.

  In such a vertical blackboard, the potential energy of the other board surface that is suspended can be used when pushing up the board surface, and the weight of the writer can be used when lowering the board surface. Even a relatively large blackboard can be moved up and down with a slight force. However, if too much force is applied during the operation, the plate surface will violently collide with the upper frame or the lower frame, resulting in an unpleasant noise for a classroom that should be quiet. In addition, the writer's finger may be caught between the rapidly descending plate surface and the lower frame, and there is a risk of injury, resulting in a safety problem. The present invention seeks to solve both the noise and safety issues.

  The plate surface that moves up and down collides with the upper frame or the lower frame because the momentum of the plate surface is excessive. Since the mass of the plate surface is constant, the movement speed of the plate surface may be reduced in order to reduce the momentum. Therefore, a braking means is provided for braking the movement of the plate surface before the plate surface and the frame collide. If the plate surface descends slowly toward the lower frame, the writer's finger or the like is pinched and the risk of injury is reduced.

  The vertical blackboard according to the present invention is provided with a braking device in a vertical section (small edge) at the left end and the right end of the front surface. The braking device includes a rotary damper. A rotary damper is an instrument that adds resistance to rotation and suppresses its rotational movement. The rotary damper included in the braking device has a property (direction) that generates rotational resistance only in one direction, and a gear (pinion) is coaxially and integrally attached. For this reason, if the pinion rotates in the forward direction, resistance is added to the rotational motion, but if the pinion rotates in the reverse direction, resistance is not added to the rotational motion.

  Parallel rails that assist the vertical movement of the front surface are provided on the left and right fore edge side of the front surface. A rack that is paired with a pinion attached to the rotary damper is fixed to the inner surface of the parallel rail. The front surface moves up and down along the parallel rails, and the pinion engages with the rack and rotates during this vertical movement. The rotational movement of the pinion is transmitted to a rotary damper provided coaxially.

  The rack is attached so that the pinion rotates in the forward direction when the front surface is pulled down. This is called a lower rack. The rack is also attached so that the pinion rotates in the forward direction when the front surface is pushed up and the rear surface is lowered. This is called an upper rack. Therefore, at least a lower rack and an upper rack must be provided on the parallel rail.

  When the pinion starts to engage with the rack, each tooth clash may cause a big impact. For this reason, an elastic leaf spring or the like is attached to the starting point of the rack to release the impact when the pinion hits. The leaf springs are preliminarily formed with teeth at the same pitch as the rack.

  In order to ensure the engagement between the pinion and the rack, it is necessary to keep the distance between them constant. Therefore, when the front surface moves along the parallel rail, a counter roller that rotates in contact with the parallel rail is attached to the front edge of the front surface so that the posture does not fluctuate. Since a rack cannot be provided on the track of the opposing roller, the operation lines of the pinion and the opposing roller must not overlap.

  The vertical blackboard according to the present invention does not cause unnecessary noise when the blackboard is moved up and down, and the plate surface operates slowly, so there is no fear of inadvertent injury to the user. . Therefore, it can be used safely even at the site where young children are taught.

It is a figure which shows the basic composition of the braking device for the vertical blackboard concerning this invention. (A) is a perspective view of the braking device attached to the front edge side of the front, and (B) is a front view showing the lower rack attached to the parallel rail and the pinion of the braking device engaging with each other. . It is a figure for demonstrating the function of the braking device for top-and-bottom type blackboards concerning this invention. (A) is a front view showing that the brake pinion engages with the lower rack when the front is pulled down and rotates, and (B) is the brake pinion with the upper rack when the front is pushed up. It is a front view which shows a meshing and rotating manner. It is a front view which shows the structure of the vertical blackboard which mounts the braking device for the vertical blackboard concerning this invention.

  Next, one embodiment of a braking device for a vertical blackboard according to the present invention will be described in detail with reference to the drawings.

<Basic configuration of braking device>
FIG. 1 is a diagram showing a basic configuration of a braking device for a vertical blackboard according to the present invention. Attach the fixing bracket 2 slightly below the fore edge of the front 1 of the vertical blackboard. The fixed metal fitting 2 is provided with a counter roller 3. The front surface 1 moves up and down along the vertical frame 13 of the vertical blackboard, and the vertical frame 13 is composed of a pair of parallel rails 6. The opposing roller 3 rotates while contacting the parallel rail 6 and moves up and down together with the front surface 1.

  Further, a rotary damper 4 is attached to the fixture 2, and the rotary damper 4 is coaxially and integrally coupled with the pinion 5. The trajectory of the pinion 5 does not overlap the trajectory of the facing roller 3. That is, the pinion 5 and the opposing roller 3 are not rotated on the same plane. In this embodiment, it is assumed that the forward rotation in which the rotary damper 4 generates resistance is clockwise.

  FIG. 2 is a view showing a state in which the front surface 1 of the vertical blackboard according to the present invention moves up and down along the parallel rails 6. A lower rack 7 is provided on the inner lower side of the parallel rail 6 with the tooth crest facing away from the writing surface, and a substantially point-symmetrical position from the lower rack 7 on the inner upper side of the parallel rail 6. In addition, the upper rack 8 is provided with the tooth teeth facing the writing surface side. That is, the teeth of the lower rack 7 and the upper rack 8 face the inner side of the parallel rail 6 but they do not face each other.

  When the front surface 1 is pulled down and the pinion 5 engages with the lower rack 7, the pinion 5 starts to rotate clockwise due to the reaction. Then, the rotary damper 4 generates a resistance that hinders rotation, so that the lowering speed of the front surface 1 decreases. Therefore, the front surface 1 does not collide with the lower frame 11. Similarly, when the front surface 1 is pushed up and the pinion 5 engages with the upper rack 8, the pinion 5 starts to rotate clockwise due to the reaction. Then, the rotary damper 4 generates a resistance that hinders rotation, so that the rising speed of the front surface 1 is lowered, and accordingly, the lowering speed of the rear surface 10 is lowered. Therefore, the rear surface 10 does not collide with the lower frame 11.

  Even when the front surface 1 of the home position is pushed up, the pinion 5 engages with the lower rack 7, but the pinion 5 starts to rotate counterclockwise due to the reaction. Since the rotary damper 4 does not generate a resistance that hinders rotation, the front surface 1 moves smoothly without decreasing the rising speed. Similarly, when the front surface 1 is pulled down from the state in contact with the upper frame 12, the pinion 5 engages with the upper rack 8, but the pinion 5 starts to rotate counterclockwise due to the reaction. Since the rotary damper 4 does not generate a resistance that hinders rotation, the front surface 1 moves smoothly without decreasing the descending speed. Thus, when the front surface 1 or the rear surface 10 is separated from the lower frame 11, no brake is applied.

<Preventing collision between pinion and rack>
Leaf springs 9 are provided at the upper end of the lower rack 7 and the lower end of the upper rack 8. When the pinion 5 starts to engage with the lower rack 7 or the upper rack 8, the leaf spring 9 serves to prevent a large impact from occurring due to a collision between the tooth teeth. The leaf spring 9 is preliminarily formed with tooth teeth at the same pitch as each rack. When the pinion 5 encounters the leaf spring 9, the leaf spring 9 bends in the direction of the force due to its elasticity. For this reason, since the momentum of the pinion 5 is reduced, the pinion 5 can be prevented from colliding violently with the lower rack 7 or the upper rack 8.

<Plate surface control>
In the longitudinal direction of the parallel rail 6, a groove serving as a moving path of the facing roller 3 is provided. The material of the opposing roller 3 is an elastic body. The opposing roller 3 rotates and moves along this groove, and applies a pressing force to the left and right rails, thereby stabilizing the relative position between the front surface 1 and the parallel rail 6. For this reason, since the distance between the pinion 5 and the parallel rail 6 is kept constant, the pinion 5 and the lower rack 7 and the pinion 5 and the upper rack 8 can always be reliably engaged. Further, the opposed roller 3 does not cause a fluctuation in posture when the front surface 1 moves along the parallel rail 6. As described above, the opposing roller 3 also controls the posture of the plate surface, and therefore may be additionally provided outside the vicinity of the rotary damper 4 (for example, on the small edge side of the rear surface 10). However, in order to make the movement of the plate surface smoother while maintaining the posture control function of the plate surface, in the vicinity of the rotary damper 4, the thickness of the opposing roller 3 is set to 0.2 to 0. 0 than the groove width. It is desirable that the length of the opposing roller 3 be longer than 5 mm, and the thickness of the opposing roller 3 be 0.2 mm shorter than the groove width.

<Application of braking device to vertical blackboard>
FIG. 3 is a view showing a state in which the braking device according to the present invention is applied to an up-and-down blackboard. The fixing bracket 2 on which the rotary damper 4 is mounted is provided slightly below both wings of the front surface 1. The position of the pinion 5 is preferably selected so that it is above the lower end of the lower rack 7 at the home position and lower than the upper end of the upper rack 8 when the front surface is in contact with the upper frame 12.

  It should be noted that the fixture 2 on which the rotary damper 4 is mounted should be fixed to the front surface 1 and is not desirably provided on the rear surface 10. When operating a vertical blackboard, it is normal to move the front. When the fixing bracket 2 is attached to the rear surface, if the front surface is pushed up vigorously, the lowering of the rear surface is braked, and the chain or the like that suspends the plate surface is slackened. This sagging leads to derailment from sprockets and pulleys and is extremely dangerous.

The damper may be a spring type or a rod type, but the plate type vibrates in the spring type, so it is necessary to provide an additional device to suppress this, and the mechanism becomes complicated. End up. In the rod type damper, the chalk powder easily adheres to the rod, so that the damper case is easy to hurt and easily causes oil leakage. Therefore, it is most preferable to use a rotary damper for the vertical blackboard braking device.

1: Front 2: Fixing bracket 3: Opposing roller 4: Rotary damper 5: Pinion 6: Parallel rail 7: Lower rack 8: Upper rack 9: Leaf spring 10: Rear surface 11: Lower frame 12: Upper frame 13: Vertical frame

Claims (4)

A pair of plate surfaces consisting hanging Do the front and rear surfaces, the upper and lower formula blackboard pulled alternately along parallel rails forming a pair provided respectively on the fore side of the right and left of the plate surface, offer for writing,
Each in fore of the right and left of the front, the pinion which rotates the rotary damper and the rotary damper coaxially and integrally generating rotational resistance only in one direction is provided,
An upper rack and a lower rack meshing with the pinion, in pairs provided on the right and left blackboard each inner parallel rails for supporting the front surface of the board, so as not to face each, and Hayama By providing them so as to be inward of each other ,
When lowering or pushing up the front, the pinion is engaged with the upper rack or lower rack, the rotational motion of the pinion is transmitted to the rotary damper and attempts to obstruct only rotation in one direction of the pinion resistance arising braking device for vertical type blackboard, characterized in that. By providing an auxiliary spring provided with tooth teeth so that it can be engaged with the pinion on one extension line of the tooth teeth of each rack,
2. The braking device for a vertical blackboard according to claim 1, wherein when the auxiliary spring engages with the pinion, the auxiliary spring bends in a direction in which force is applied from the pinion. By providing a counter roller on the front edge of the front surface, rotating while in contact with both sides of the parallel rail, and the rotation trajectory does not overlap with the rotation trajectory of the pinion,
The relative position between the rack provided on the parallel rail and the pinion provided on the front edge of the front surface is maintained constant by the force of the opposing roller pressing the parallel rail. Item 3. The braking device for a vertical blackboard according to item 1 or 2. Claims 1 comprises a braking device for a vertical type blackboard according to any one of 3, vertical type blackboard, characterized in that.