Electric lifting device

Abstract

To provide an electrically operated lifting device that can stably raise and lower large, heavy main boards (such as blackboards). [Solution] The electric lifting device of the present invention comprises a main board positioned on the front side of a wall, an extendable support column supporting the bottom of the main board, an electric actuator incorporated into the support column that extends and retracts the support column to raise and lower the main board, a rail member fixed to the wall so as to extend in the vertical direction, a bracket member fixed to the back of the main board and slidable relative to the rail member, and a controller that issues a command to the electric actuator to extend and retract the support column via an operating switch.

Description

Technical Field

[0001] The present invention relates to an electric lifting device for lifting and lowering a main board. In the present invention, the main board refers to a blackboard, a whiteboard, a bulletin board, a monitor, a large TV, an electronic blackboard, or an electronic board.

Background Art

[0002] Generally, a blackboard is fixedly attached to the wall surface of a classroom or lecture hall. If the mounting position of the blackboard is low, the characters written at the lower part of the blackboard will be blocked by the front seated persons and be difficult to see. If the mounting position of the blackboard is high, a person of short stature will find it difficult to write characters at the upper part of the blackboard. Therefore, it is desirable to configure the blackboard to be able to be lifted and lowered. However, a blackboard, for example, with a size of about 3 m in width × 1 m in height weighs about 20 kg, and a blackboard with a size of about 4.5 m in width × 1 m in height weighs about 50 kg and is heavy. Patent Document 1 discloses a manual lifting blackboard that can absorb the weight of the blackboard by a balancing device composed of a spring and a drum and lift and lower the blackboard with a small force. Patent Document 2 discloses a lifting device that installs an electric motor on the wall surface at the back of the blackboard and electrically lifts and lowers the blackboard.

[0003] However, even if a manual lifting blackboard has a balancing device, it may require force when the blackboard is enlarged. Therefore, it is desirable to make it electric-powered. However, even in an electric lifting device, due to the structure of installing a lifting mechanism including an electric motor on the wall surface on the back side of the blackboard, when inspecting the lifting mechanism, it is necessary to remove the blackboard, and maintenance is not easy.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The objective of the present invention is to provide an electric lifting device that can modify existing wall-mounted main boards, such as blackboards, to allow for electric lifting, and that can stably lift even large and heavy main boards. [Means for solving the problem]

[0006] The electric lifting device according to the present invention is characterized by comprising: a main board positioned on the front side of a wall; an extendable support column supporting the bottom of the main board; an electric actuator incorporated into the support column and extending or retracting the support column to raise and lower the main board; a rail member fixed to the wall so as to extend in the vertical direction; a bracket member fixed to the back of the main board and slidable relative to the rail member; and a controller that issues a command to the electric actuator to extend or retract the support column via an operating switch.

[0007] The bracket member may be equipped with a plurality of rollers that, while in contact with the rail member, prevent tilting in two orthogonal directions.

[0008] The electric actuator may include a DC motor that extends and retracts the support column, and a gear mechanism that connects the DC motor and the support column, reducing the rotation of the DC motor and converting it into the extension and retraction of the support column. [Effects of the Invention]

[0009] To explain the main board using a blackboard as an example, in the electric lifting device of the present invention, the bottom of the blackboard is supported by an extendable support column, so compared to fixing the blackboard to the wall with screws, it can stably support a heavy blackboard. Since the electric actuator that extends and retracts the support column is built into the support column, even large blackboards can be raised and lowered. Because the electric actuator is inside the support column, it is not hidden behind the blackboard, making maintenance easy. There is no need to remove the blackboard when inspecting the lifting device. A bracket member is fixed to the back of the blackboard, and the bracket member is slidably attached to the rail member, so the blackboard can be raised and lowered stably.

[0010] The bracket member is equipped with multiple rollers that, while in contact with the rail member, prevent tilting in two perpendicular directions, thus preventing the blackboard from tilting in the front-to-back direction and the left-to-right direction. The rollers also have the effect of reducing friction between the bracket and the rail when raising and lowering the blackboard, allowing for smoother sliding.

[0011] The electric actuator is equipped with a DC motor that extends and retracts the support column, allowing the required DC motor speed to be determined by voltage. The rotation speed can be adjusted to match the weight of the blackboard. A gear mechanism is included that converts the rotation of the DC motor into extension and retraction of the support column, allowing the blackboard to slide up and down by extending and retracting the support column. The combination of gears reduces the rotation speed of the DC motor, enabling increased torque for lifting and lowering. Due to the high torque, even heavy blackboards can be lifted and lowered. [Brief explanation of the drawing]

[0012] [Figure 1] This is an overall structural diagram of the electric lifting device according to the present invention. [Figure 2] This is a perspective view showing the relationship between the rail member and the bracket member. [Figure 3] This is a plan view showing the relationship between the rail member and the bracket member. [Figure 4] This is a right side view of the electric lifting device according to the present invention. [Figure 5]This is a structural diagram of an electric actuator installed inside a support column. [Figure 6] This is a diagram showing the gears of a reduction gear for an electric actuator. [Figure 7] This is a front view with the main board raised. [Figure 8] This is a front view with the main board lowered. [Modes for carrying out the invention]

[0013] The electric lifting device according to the present invention will be described in detail below with reference to the drawings.

[0014] Figure 1 is an overall structural diagram of the electric lifting device 100 according to the present invention. The main board 1 refers to one of the following: a blackboard, a whiteboard, a bulletin board, a monitor, a large television, an electronic blackboard, or an electronic board. The electric lifting device 100 comprises a main board 1 positioned on the front of the interior wall surface 10, an extendable support column 2 supporting the bottom of the main board 1, an electric actuator 3 that extends and retracts the support column 2 to raise and lower the main board 1, a rail member 4 fixed to the back of the main board so as to extend vertically along the wall surface 10, a bracket member 5 fixed to the back of the main board 1 and slidable relative to the rail member 4 by the rail member 4 being inserted through it, and a controller 6 that issues a command to the electric actuator 3 to extend and retract the support column 2 via an operation switch 17. The electric actuator 3 is built into the support columns 2, 2. The controller 6 is attached to the bottom of the main board 1. This allows the operation switch 17 to be placed at a height that is easy to operate. The controller 6 is provided with a 100V household voltage outlet. The electric actuators 3, 3 located within the left and right support columns 2, 2 are powered by a voltage converted from AC to DC by the controller 6. As shown by the arrows in Figure 1, when the electric actuators 3 extend or retract the support columns 2, the main board 1 moves up and down. The rail member 4 extends vertically and has fixing protrusions 4a on the left and right sides, and is fixed to the wall surface 10 with screws.

[0015] Figure 2 is a perspective view showing the relationship between the rail member 4 and the bracket member 5. The bracket member 5 in Figure 2 is the bracket member shown in the upper right of Figure 1. The bracket member 5 is fixed to the upper frame of the main board 1 by screwing into the screw hole 5b of the edge portion 5a. The rail member 4 is composed of three adjacent hollow square bars, and the left and right hollow square bars are provided with slits 18 on the outer sides in the left and right directions. The bracket member 5 is provided with a plurality of front or rear tilt prevention rollers 7a and a plurality of left or right tilt prevention rollers 7b. These rollers 7 (7a, 7b) prevent the rail member 4 from tilting in two orthogonal directions. The bracket member 5 is provided with rollers 7 (7a, 7b) so as to sandwich the inside and outside of the rail member 4.

[0016] Figure 3 is a plan view showing the relationship between the rail member 4 and the bracket member 5. The bracket member 5 in Figure 3 is the bracket member shown in the upper right of Figure 1. The front or rear tilt prevention rollers 7a, 7a are located inside the rail member 4, and the left or right tilt prevention rollers 7b, 7b are located outside the rail member 4. In addition, left or right tilt prevention rollers 7b', 7b' are provided on the bracket member 5 so as to be located inside the rail member 4. These rollers 7 (7a, 7b, 7b') are provided in a total of 12 in two upper and lower rows inside one bracket member 5.

[0017] When the main board 1 tilts in the front-rear direction or the left-right direction, the rollers 7 (7a, 7b, 7b') contact the rail member 4 and the tilt is prevented. Since the rollers 7 (7a, 7b, 7b') are pivotally supported so as to be rotatable, when the main board 1 is lifted or lowered, the sliding friction with the rail member 4 can be reduced. Note that not only the rollers 7 (7a, 7b, 7b'), but also rollers, spheres, slide bearings, etc. may be used. The bracket member 5 in Figure 3 has an edge portion 5a and is fixed to the upper frame 8 of the main board 1 by screwing into the screw hole 5b.

[0018] Figure 4 is a right side view of the electric lifting device 100 according to the present invention. The rail member 4 is fixed to the wall surface 10 with screws. A bracket member 5 is provided slidably with respect to the rail member 4. The bracket member 5 can slide along the slit 18 of the rail member 4. The upper bracket member 5 has its edge 5a connected to the upper frame 8 of the main board 1 with screws, and the lower bracket member 5 has its edge 5a connected to the lower frame 9 of the main board 1 with screws. The bottom of the main board 1 is connected to and supported by the upper parts of the support columns 2, 2 spaced apart left and right, so that when the support columns 2, 2 expand and contract, the main board 1 moves up and down.

[0019] Figure 5 is a structural view of the electric actuator 3 provided inside the support column 2. Fig. 5(A) shows the state of the electric actuator 3 when the main board 1 is lowered, and Fig. 5(B) shows the state of the electric actuator 3 when the main board 1 is raised. The support column 2 is formed from an upper stage 2a, a middle stage 2b, and a lower stage 2c and is capable of expanding and contracting. The upper stage 2a is connected to the lower frame 9 of the main board with L-shaped metal fittings on the left and right sides. The electric actuator 3 is disposed inside the lower stage 2c of the support column 2. The electric actuator 3 comprises a DC motor 11 and a gear mechanism 20 that decelerates the rotation of the DC motor 11 and converts it into the expansion and contraction of the support column 2. The gear mechanism 20 comprises a reduction gear 12, a ball screw 13, lifting tables 14, 14 attached to the ball screw 13, a lifting shaft 15 that is connected to the lifting tables 14, 14 and raises and lowers the upper stage 2a of the support column 2, and a guide 16 that guides the lifting tables 14, 14 in the vertical direction.

[0020] When the DC motor 11 is rotated forward, the ball screw 13 rotates via the reduction gear 12, causing the lifting tables 14, 14 to rise and the lifting shaft 15 to rise, pushing up the upper section 2a of the support column 2 as shown in Figure 5(B). When the DC motor 11 is rotated backward, the ball screw 13 rotates backward via the reduction gear 12, causing the lifting tables 14, 14 to descend and the lifting shaft 15 to descend, pulling down the upper section 2a of the support column 2 as shown in Figure 5(A). The extension and retraction of the support column 2 is controlled by the operation switch 17 of the controller 6. The operation switch 17 is a momentary switch; while pressed upward, an up signal is output to raise the column, and when released, the signal stops in the neutral state. While pressed downward, a down signal is output to lower the column, and when released, it returns to the neutral state. The DC motor 11 rotates for the duration that the up signal or down signal is output.

[0021] Figure 6 shows the reduction gear 12 of the electric actuator 3. When the first gear 12a is rotated on the shaft 11a of the DC motor 11, and the second gear 12b which meshes with the first gear 12a is rotated, for example, if the number of teeth of the second gear 12b is five times that of the first gear 12a, the rotation of the shaft of the second gear 12b can be reduced to 1 / 5. If a third gear 12c is provided on the shaft of the second gear 12b, and a fourth gear 12d which meshes with it is provided, and the number of teeth of the fourth gear 12d is five times that of the third gear 12c, the rotation speed of the fourth gear 12d, which is centered on the ball screw 13, can be further reduced to 1 / 5. For example, if the rotation speed of the DC motor 11 is 5000 rpm, it can be reduced to 200 rpm. In this way, the lifting and lowering speed of the main board 1 can be adjusted.

[0022] Figure 7 is a front view when the main board 1 is raised. The support column 2 extends upward, raising the main board 1. The bracket member 5 attached to the main board 1 slides along the rail member 4, raising the main board 1.

[0023] Figure 8 is a front view when the main board 1 is lowered. The support column 2 retracts downward, causing the main board 1 to descend. The bracket member 5 attached to the main board 1 slides along the rail member 4, causing the main board 1 to rise. [Industrial applicability]

[0024] The present invention is suitable, for example, for an electrically operated lifting device for a blackboard. [Explanation of Symbols]

[0025] 1 Mainboard 2 Support pillar 2a Upper 2b middle row 2c lower row 3 Electric Actuator 4 Rail members 4a Fixing protrusion 5 Bracket member 5a Edge 5b Screw hole 6 Controllers 7 Laura 7a Roller to prevent forward or backward tilting 7b Roller to prevent left or right tilt 8. Top frame of the main board 9. Lower frame of the main board 10 Wall surface 11 DC motor 11a Rotation axis 12 Reduction gear 12a First gear 12b Second Gear 12c 3rd gear 12d 4th gear 13 Ball screw 14 Height-adjustable table 15 Lifting shaft 16 Guide 17. Operation switches 18 slits 20 Gear mechanism 100 Electric lifting device

Claims

1. The main board is located on the front side of the wall, The main board has an extendable support column that supports the bottom of the main board, An electric actuator incorporated into the support column extends and retracts the support column to raise and lower the main board, A rail member fixed to the wall surface so as to extend in the vertical direction, A bracket member fixed to the back of the main board and slidable relative to the rail member, The system includes a controller that issues a command to the electric actuator via an operating switch to extend or retract the support column, The electric lifting device is characterized in that the support columns support the main board at different positions in the longitudinal direction of the main board with respect to the rail members.

2. The bracket member is The electric lifting device according to claim 1, further comprising a plurality of rollers that, while in contact with the rail member, prevent tilting in two orthogonal directions.

3. The aforementioned electric actuator is The aforementioned support column is connected to a DC motor that extends and retracts, The electric lifting device according to claim 1, further comprising a gear mechanism that connects the DC motor and the support column, and reduces the rotation of the DC motor to convert it into extension and retraction of the support column.

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