Table apparatus

Abstract

To provide a table device capable of changing an inclination angle of a table by two actuators.SOLUTION: This table device 1 is provided with a table 10, a base 20, two actuators 30 and one support 40 laid between the table and the base, a fall preventing means 50 for preventing the fall of the actuators, a sensor 60 for detecting the inclination of the base, and a control part 70 for controlling the drive of the actuators based on the output signal of the sensor. The actuator includes a movable part 31 and a main body part 32, the movable part is connected to the table via a ball joint 33, the main body part is connected to the base via a ball joint 34, an upper end part 41 of the support is connected to the table via the ball joint, and a lower end part 43 of the support is fixed to the base. To support a table at three points by two actuators and one strut. Since the overturn preventing means is provided, the inclination angle of the table can be changed by the two actuators.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a table device that can change the tilt angle of a table using two actuators. [Background technology]

[0002] 2. Description of the Related Art Table devices are known that can drive an actuator to maintain a table in a horizontal position or change the angle to any desired position. For example, Patent Document 1 discloses a device in which a table is supported from below by three electromagnetic actuators, and the actuators are driven based on signals from a gyro attached to the table to maintain the table in a horizontal state. Patent Document 2 discloses a technology for maintaining the platform of a transport vehicle in a horizontal position, in which the platform is supported from below by three hydraulic cylinders and the drive of each hydraulic cylinder is controlled based on the pitching angle and rolling angle detected by an inclinometer. Many mechanisms are known that support a table with three actuators in this way and maintain the table in a horizontal state by controlling the drive of each actuator (Patent Documents 3 and 4). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-138265 [Patent Document 2] Japanese Patent Application Publication No. 4-325384 [Patent Document 3] Japanese Patent Application Publication No. 2023-114174 [Patent Document 4] Patent No. 5490650 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the techniques disclosed in the above patent documents have problems such as increased manufacturing costs and a higher possibility of failure because three actuators are used.

[0005] In consideration of the above-mentioned problems, an object of the present invention is to provide a table device that can change the tilt angle of a table using two actuators. [Means for solving the problem]

[0006] The table device of the present invention comprises a table, a base placed below the table, two actuators and one support pillar that are spanned between the table and the base to support the table, anti-tip means that prevents the actuators from tipping over, a sensor that detects the inclination of the base, and a control unit that controls the drive of the actuators based on the output signal of the sensor, and is characterized in that the actuators comprise a movable part and a main body part that supports the movable part so that it can move freely, the two movable parts are connected to one of the table and the base via ball joints, the two main body parts are connected to the other of the table and the base via ball joints, the upper ends of the pillars are connected to the table via ball joints, and the lower ends of the pillars are fixed to the base. The anti-tip device may further include a protrusion fixed to the table and a guide for guiding the movement of the protrusion in the up and down direction. The sensor is a three-axis acceleration sensor, and the control unit controls the driving of the actuator based on a resultant acceleration obtained by combining the acceleration calculated by the acceleration sensor and the acceleration of gravity. [Effects of the Invention]

[0007] In this invention, the table is supported at three points using two actuators and one support. Since a tip-over prevention mechanism is provided to prevent the actuators from tipping over, the table tilt angle can be changed using just two actuators, reducing manufacturing costs. Furthermore, compared to configurations using three or more actuators, the structure of the table device can be simplified, reducing the possibility of breakdowns. By using a protrusion fixed to the table and a guide that guides the up-and-down movement of the protrusion, the structure of the tip-over prevention means can be simplified and calculations for calculating the table coordinates can be made easier. If the control unit controls the drive of the actuator based on the resultant acceleration obtained by combining the acceleration calculated by the acceleration sensor and the acceleration of gravity, the tilt angle of the table can be changed as desired, even when the table device is mounted on a vehicle, for example. [Brief explanation of the drawings]

[0008] [Figure 1] Perspective view of the table device [Figure 2] Front view (a), left side view (b), rear view (c), and plan view (d) of the table device [Figure 3] Table device block diagram [Figure 4] 1A is a perspective view of the table device without a tip-over prevention means, and FIG. 1B is a rear view of the table device. [Figure 5] 1A and 1B are perspective views schematically illustrating a table device; [Figure 6] Left side view of the table device (a) to (c) [Figure 7] Rear view of the table device (a) and (b) [Figure 8] Left side view of table device [Figure 9] 10A and 10B are a rear view and a left side view showing a modified example of the table device; [Figure 10] 10A to 10C are diagrams illustrating a control method for a table device according to a second embodiment; [Figure 11]10A is a left side view showing a state in which the table device is applied to a wheelbarrow in the third embodiment; FIG. 10B is a rear view showing a part of the wheelbarrow; FIG. 10C is a left side view showing a state in which the carrier is rotated; and FIG. 10D is a front view showing a part of the wheelbarrow on an inclined surface. DETAILED DESCRIPTION OF THE INVENTION

[0009] [First embodiment] A first embodiment of a table device according to the present invention will be described. 1 to 3, the table device 1 includes a table 10, a base 20, two actuators 30, a support 40, a tip-over prevention means 50, a sensor 60, and a control unit 70. Although not shown, a battery required to drive the actuators 30 and the control unit 70 is attached to the base 20.

[0010] The table 10 is a member on which an object is placed on its surface. The shape of the table 10 is not particularly limited, and in this embodiment, it has a substantially triangular shape when viewed from above. The base 20 is a member for supporting the actuator 30 and the like, and is disposed below the table 10. The shape of the base 20 is not particularly limited, and in this embodiment, like the table 10, it is approximately triangular when viewed from above.

[0011] The actuator 30 includes a movable part 31 and a main body part 32 that movably supports the movable part 31. The type of actuator 30 is not particularly limited as long as the movable part 31 can perform reciprocating linear motion, and for example, a cylinder, a ball screw drive actuator, a linear motor, or the like may be used. The two actuators 30 are arranged at two of the three corners that form the table 10 and the base 20. Specifically, the two movable parts 31 are connected to the rear surfaces of the two corners of the table 10 via ball joints 33, and the two main body parts 32 are connected to the front surfaces of the two corners of the base 20 via ball joints 34. In addition, the two movable parts 31 may be connected to the surfaces of the two corners of the base 20 via ball joints 33, and the two main body parts 32 may be connected to the back surfaces of the two corners of the table 10 via ball joints 34.

[0012] The support 40 is a rod-shaped body without a movable part 31, and its upper end 41 is connected to the back surface of one remaining corner of the table 10 via a ball joint 42, and its lower end 43 is fixed to the surface of one remaining corner of the base 20. In this way, two actuators 30 and one support column 40 are provided between the table 10 and the base 20, thereby supporting the table 10 at three points.

[0013] The tip-over prevention means 50 is a means for preventing the actuator 30 from tipping over. If the table device 1 were not equipped with the tip-over prevention means 50 as shown in Figure 4(a), each actuator 30 would not be able to stand on its own and would tip over, as shown in Figure 4(b), since its main body 32 is simply connected to the base 20 via the ball joint 34. The tip-over prevention means 50 can also be said to be a means for keeping the actuator 30 standing on its own.

[0014] Specifically, the tip-over prevention means 50 includes a protrusion 51 and a guide 52 . Convex portion 51 is fixed to table 10 and moves integrally with table 10. Guide 52 guides the vertical movement of convex portion 51 and has slit 53 extending in the vertical direction. The lower end of guide 52 is fixed to base 20. When actuator 30 tilts slightly from its freestanding state, convex portion 51 comes into contact with either the left or right inner surface of slit 53, preventing actuator 30 from tilting any further and allowing it to maintain its freestanding state.

[0015] The sensor 60 is attached to the base 20 and detects the tilt of the base 20 and outputs a signal to the control unit 70. There are no particular limitations on the type of sensor 60 as long as it can detect the tilt of the base, and for example, an IMU sensor such as an acceleration sensor or a gyro sensor may be used. The control unit 70 controls the driving of the actuator 30 based on the output signal of the sensor 60, and specifically controls the inclination angle of the table 10 relative to the horizontal plane by adjusting the amount of movement of the movable part 31 based on the output signal of the sensor 60.

[0016] An example of a method for calculating the coordinates of the table 10 required when the control unit 70 controls the tilt angle of the table 10 relative to the horizontal plane will be described. Assume that by tilting the base 20 from the horizontal attitude (reference coordinate system) as shown in Fig. 5(a) to the position as shown in Fig. 5(b), a rotation matrix R is obtained from the axis attitude angles of the IMU sensor (not shown) attached to the base 20. However, this R does not include the rotation component around the y-axis. At this time, the coordinates of three points on the table surface in the base coordinate system are calculated.

[0017] (1) The coordinates of reference point A on the table surface correspond to the coordinates (0, L, 0) in the base coordinate system. (2) The vector (Vd x , Vd y , Vd z ) is equal to the vector of the line projected onto the table surface. Therefore, the x-axis of the base coordinate system is the reference coordinate system (vd x , vd y , vd z ) R×(vd x , vd y , vd z ) = (-1, 0, 0), so (vd x , vd y , vd z ) = R -1 × (-1, 0, 0) The vector of the line projected onto the table surface was normalized by eliminating the y-axis component in the reference coordinate system (αvd x , 0, αvd z ) where α is (vd x , 0, vd z ) is the normalization factor for Therefore, the vector (Vd x , Vd y , Vd z ) becomes: (Vd x , Vd y , Vd z ) = R × (αvd x , 0, αvd z )

[0018] (3) The vector (Vb x , Vb y , Vb z ) and the vector (Vc x , Vc y , Vc z ) (2) The vector (αvd x , 0, αvd z ) is rotated 30 degrees and 330 degrees around the y-axis (0, 1, 0) of the reference coordinate system, and the vector (αvb x , 0, αvb z ) and (αvc x , 0, αvc z ) is found. The calculation is performed by converting from the reference coordinate system to the work coordinate system as follows: (Vb x , Vb y , Vb z ) = R × (αvb x , 0, αvb z ) (Vc x , Vc y , Vc z ) = R × (αvc x , 0, αvc z )

[0019] (4) The coordinates of two points BC on the work surface in the base coordinate system (the coordinates are found = the length of the cylinder is also found) The following calculation is performed using the values ​​obtained in (1), (2), and (3). B coordinate: (Pb x , Pb y , Pb z ) = lw × (Vb x , Vb y , Vb z ) C coordinates: (Pc x , PC y , PC z ) = lw × (Vc x , Vc y , Vc z )

[0020] For example, when an attempt is made to change the base 20 from a horizontal state as shown in Figure 6(a) to a state in which the front is tilted downward as shown in Figure 6(b), the sensor 60 detects the tilt of the base 20 and outputs a predetermined value (signal) to the control unit 70. As shown in Figure 6(c), the control unit 70 contracts the two actuators 30 based on the output signal. Because the table 10 is connected to the two actuators 30 at two points on its rear side via ball joints 33, the rear of the table 10 moves downward in response to the contraction of the actuators 30, thereby maintaining the horizontal state of the table 10. At this time, the convex portion 51 moves downward within the slit 53.

[0021] 7(a), when an attempt is made to change the position of the base 20 downward to the left, the control unit 70 extends the left actuator 30 and contracts the right actuator 30 as shown in FIG. 7(b), thereby maintaining the horizontal position of the table 10. At this time, a force that tends to tip the two actuators 30 to the left due to gravity acts on them, but the protrusion 51 comes into contact with the right side of the inner surface of the slit 53, preventing the two actuators 30 from tipping over. It is not necessary to maintain the table 10 in a horizontal state. For example, the control unit 70 may adjust the tilt angle of the table 10 so that it is always tilted forward at a certain angle relative to the horizontal plane when viewed from the side, as shown in Figure 8. 9, a cover 54 that covers the periphery of each actuator 30 may be fixed to the base 20 as the tip-over prevention means 50. When an actuator 30 tries to tip over, it comes into contact with the cover 54, thereby preventing the actuator 30 from tipping over.

[0022] [Second embodiment] A second embodiment of the table device of the present invention will be described. The same components as those in the first embodiment will be designated by the same reference numerals and the description thereof will be omitted. This embodiment is characterized in that the sensor 60 is a three-axis acceleration sensor, and the control unit 70 controls the driving of the actuator 30 based on a resultant acceleration obtained by combining the acceleration calculated by the three-axis acceleration sensor and the acceleration of gravity. The table device of this embodiment is particularly effective when used in a vehicle.

[0023] As shown in FIG. 10(a), when a cup 81 containing water 80 is placed on a table 10 and a vehicle (not shown) is started, the water 80 may spill out of the cup 81 during acceleration. Therefore, as shown in Figure 10(b), the three-axis acceleration sensor calculates a resultant acceleration α3, which is a combination of the acceleration α1 caused by vehicle acceleration and the gravitational acceleration α2. The control unit 70 then calculates the angle θ that satisfies tan θ = α1 / α2, and controls the drive of the two actuators 30 so that the table 10 is tilted at the angle θ with respect to the horizontal plane, as shown in Figure 10(c). This prevents water 80 from spilling out of the cup 81. The control unit 70 adjusts the tilt angle of the table 10 in response to changes in the acceleration of the vehicle while it is running. When the vehicle moves from an accelerating state to a constant speed state, the control unit 70 returns the table 10 to a horizontal state.

[0024] [Third embodiment] A third embodiment of the table device of the present invention will be described, but the same reference numerals will be used to designate the same components as those in the above-described embodiments, and the description thereof will be omitted. As shown in FIG. 11, in this embodiment, a configuration in which the table device is applied to a wheelbarrow 90 will be described.

[0025] As shown in Figure 11(a), the loading platform 91 corresponds to the table 10, and the frame 92 corresponds to the base 20. The front part of the loading platform 91 is pivotally supported by the frame 92, and the loading platform 91 is structured to be rotatable around a pivot point 93. As shown in FIG. 11(b), the movable parts 94a of the two actuators 94 are pivotally supported on the left and right sides of the rear part of the loading platform 91, and the main body parts 94b are pivotally supported on the left and right sides of the frame 92. A protrusion 95a of the tip-over prevention means 95 is attached to the rear of the loading platform 91, and a guide 95b is attached to the rear of the frame 92. As the loading platform 91 rotates, the protrusion 95a moves up and down within the slit of the guide 95b. A sensor 96 is attached to the frame 92.

[0026] When a user holds the handle 97 and lifts the platform 91 upward with luggage 100 loaded on it, the sensor 96 detects a change in the position of the frame 92, and the control unit 70 extends the two actuators 94, as shown in FIG. 11(c). Extending the two actuators 94 causes the platform 91 to tilt forward, and the center of gravity of the platform 91 with luggage 100 loaded on it moves forward, that is, toward the tires 98. Shifting the center of gravity of the platform 91 toward the tires 98 allows the user to hold the handle 97 with less force, thereby reducing the burden on the user. As shown in FIG. 11(d), on an inclined surface 99, the control unit 70 extends one actuator 94 and contracts the other actuator 94 to maintain the horizontal position of the loading platform 91, so there is no risk of the luggage 100 falling off the loading platform 91. [Industrial Applicability]

[0027] INDUSTRIAL APPLICABILITY The present invention is a table device that can change the tilt angle of a table using two actuators, and has industrial applicability. [Explanation of symbols]

[0028] 1 Table device 10 tables 20 Foundation 30 Actuator 31 Moving parts 32 Main body 33 Ball Joint 34 Ball Joint 40 pillars 41 Upper end 42 ball joint 43 Lower end 50 Fall prevention measures 51 Convex part 52 Guide 53 Slit 54 Cover 60 sensors 70 Control Unit 80 water 81 cups 90 Wheelbarrow 91 Cargo bed 92 frames 93 Axis support point 94 Actuator 94a Moving part 94b Main body 95 Fall prevention measures 95a Convex part 95b Guide 96 sensors 97 Handle 98 Tires 99 Slope 100 luggage

Claims

1. the device comprises a table, a base placed below the table, two actuators and one support strung between the table and the base to support the table, a tip-over prevention means for preventing the actuators from tipping over, a sensor for detecting the tilt of the base, and a control unit for controlling the driving of the actuators based on an output signal from the sensor, the actuator includes a movable portion and a main body portion that movably supports the movable portion, the two movable parts are connected to one of the table and the base via ball joints; The two main bodies are connected to the other of the table and the base via ball joints, A table device, characterized in that an upper end of the support column is connected to the table via a ball joint, and a lower end of the support column is fixed to the base.

2. 2. The table device according to claim 1, wherein the tip-over prevention means comprises a protrusion fixed to the table and a guide for guiding the movement of the protrusion in the up and down direction.

3. 3. The table device according to claim 1, wherein the sensor is a three-axis acceleration sensor, and the control unit controls the driving of the actuator based on a resultant acceleration obtained by combining the acceleration calculated by the acceleration sensor and gravitational acceleration.

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