JP6244517B2 - Load support mechanism - Google Patents

Description

  The present invention relates to a support mechanism for supporting loads of various articles and the like, and particularly to a load support mechanism for supporting a target article at a desired position and displaceably.

  Conventionally, various support mechanisms have been proposed in order to support articles such as computers, television monitor devices, OA desks, work table tops, and heavy objects so that they can be raised and lowered to a desired height position. For example, a monitor device support mechanism is known that can move the monitor device up and down and can be positioned with a constant support force (see, for example, Patent Document 1).

  The monitor device support mechanism described in Patent Document 1 includes at least one cam, at least one cam follower member, an energy storage member such as a spring, and a moving body for mounting the monitor device. In the monitor support mechanism, when the moving body moves along a fixed base, the spring is compressed / expanded by the cam, and the elastic energy stored in the spring is increased / decreased. The spring force of the spring is converted into a reaction force from the cam surface against the cam follower member, and this reaction force includes a first component in the moving direction of the moving body and a second component substantially orthogonal thereto. . The shape of the cam is such that even if the second component increases / decreases due to the compression / extension of the spring, the first component in the moving direction is kept constant, and a substantially constant supporting force acts on the moving body and the monitoring device. Designed to do.

  According to Patent Literature 1, the force for urging the moving moving body and the monitor in the moving direction is kept substantially constant by such a combination of the spring and the cam shape. Therefore, when a slight force is applied to the moving body or the monitor device by hand, the monitor device can be easily moved. When the force is released, the moving body and the monitor device are localized at the new support position.

JP 2002-303304 A

  This kind of article support mechanism is preferably configured in a small size and light weight from a practical point of view, with a simple structure and a small number of parts. However, in the monitor device support mechanism described in Patent Document 1, the coil spring of the energy storage member is arranged in a direction in which the axial direction thereof is substantially perpendicular to the moving direction of the monitor device, and the spring force rotates the moving body. The cam follower at the tip of the arm member that is attached is pressed against the cam surface. The force for supporting the monitor device is obtained only by the first component in the moving direction of the moving body, not all of the reaction force from the cam surface to the cam driven member.

  Therefore, a large coil spring that can exert a spring force considerably larger than the weight of the moving body and the monitor device is required as the energy storage member. Moreover, the coil spring is disposed on the front side and / or the back side of the cam. As a result, the monitor apparatus support mechanism disclosed in Patent Document 1 is difficult to reduce the size and weight because the entire apparatus is particularly large in the depth direction and complicated in structure.

  Furthermore, the monitor device support mechanism described in Patent Document 1 determines the support force of the monitor device by a combination of a spring and a cam shape. It is necessary to replace the support mechanism or the support mechanism itself. Therefore, a separate support mechanism or component must be prepared for each weight of the target article to be supported, resulting in a problem that the price increases.

  On the other hand, in a state where the load of the article to be supported and the pushing force of the spring are balanced, the article can be pushed up and pushed down from the stationary position with a relatively small force. However, on the other hand, if the weight of the article is large, the inertial force acting during the movement also increases accordingly, so that a large force is required to stop the article, or it is difficult to stop the article at a desired position. There is a risk of becoming.

  The present invention has been made in view of the above-described problems, and an object of the present invention is a load support mechanism capable of supporting a load of an article or the like in a stationary state so as to be displaceable. An object of the present invention is to provide a load support mechanism that is simple and has a small number of parts, can be easily downsized, and can safely and reliably move an article or the like to a desired position.

The load support mechanism of the present invention is a support member for supporting a load that is movable in a predetermined range along a predetermined direction;
A spring member having one end fixed and the other end exerting a biasing force in a direction along the moving direction of the support member against the load;
The load and the urging force are transmitted between the support member and the other end of the spring member, and are disposed so as to be displaced along the moving direction together with them, and are inclined at a predetermined angle with respect to the direction of the urging force. A cam follower that is in contact with one cam surface and the first cam surface;
A second cam surface that is inclined at a predetermined angle with respect to the direction of the urging force and abuts the cam follower;
A side support portion that generates a reaction force that restricts displacement of the first cam surface in a direction perpendicular to the direction of the biasing force with respect to the load and / or the biasing force;
A controllable drive mechanism for moving the support member along its moving direction;
The pressing force of the second cam surface to the cam follower is a component in the first direction along the direction of the biasing force generated by the position within the predetermined range in which the support member can move, and at least in the direction of the biasing force. A second direction component orthogonal to each other,
When the drive mechanism is stopped, the first cam surface and the second cam surface act on the cam follower, the urging force of the spring member, the pressing force of the second cam surface on the cam follower, and the first side support portion. It is designed so that the reaction force to the cam surface is balanced in the predetermined range in which the support member can move.

  Here, “equilibrium” means that when several external forces are acting on a certain object or member (for example, a cam follower), the resultant force is zero throughout the specification, and as a result, the object Or it shall say that the member is in a stationary state. In addition, the external force acting on the object or member is generated in the friction force generated between the object or member and another object or member, or in another object or member causing the external force to act on the object or member. Includes frictional force.

  In such a configuration, the pressing force from the first cam surface to the cam follower includes a first direction component along the direction of the urging force and a second direction component orthogonal thereto, The component is a reaction force of the side support portion to the first cam. Therefore, when the force acting around the cam follower is in an equilibrium state, the direction of the biasing force includes the load, the biasing force of the spring member, and the pressing force of the second cam surface to the cam follower in the first direction. In a direction that is balanced with the component and orthogonal to the direction of the urging force, a reaction force on the first cam surface of the side support portion, that is, a component in the second direction of the pressing force from the first cam to the cam follower, The component in the second direction of the pressing force to the cam follower of the second cam surface is balanced.

  Usually, since the biasing force of the spring member varies depending on the displacement, it is smaller or larger than the load depending on the position of the support member. According to the present invention, when the force is in an equilibrium state in the direction of the biasing force, the component in the first direction of the pressing force to the cam follower of the second cam surface is less than the load of the spring member This acts in the direction of assisting this, and when it is larger than the load, it acts in the direction of reducing this. Therefore, the supporting member can be held in a desired position and easily moved with a small force within a predetermined movable range while the load is supported. Moreover, since the support member is moved by a controllable drive mechanism, it can be safely and reliably performed even when the load is relatively large.

  Further, the spring member does not need to exert an urging force that exceeds the load in the entire movement range of the support member. Accordingly, it is possible to employ a relatively small and light-weight one, and the entire apparatus can be reduced in size and weight.

  In one embodiment, the drive mechanism can control the start, stop, orientation or speed of movement of the support member. Accordingly, the movement of the support member can be more reliably controlled in accordance with the magnitude of the load and the size / shape of the article.

  In another embodiment, the second cam surface can change its orientation relative to the cam follower in response to different loads, and the first cam surface and the second cam surface are relative to the cam follower of the second cam surface. Even if the direction is changed, the force acting around the cam follower can be maintained in an equilibrium state. Thereby, even if the magnitude of the load to be supported changes, the support member is held in a desired position and held movably by simply changing the direction of the second cam surface to the cam follower member. The function of the present invention can be ensured. Moreover, there is no need to replace the first cam surface, the second cam surface, or the spring member, or the entire device, which is advantageous.

FIG. 1 is a perspective view of an embodiment of a load support mechanism according to the present invention. FIG. 2 is a perspective view of the load support mechanism of the present embodiment as viewed from the opposite side of FIG. FIG. 3 is an exploded perspective view of this embodiment. FIG. 4 is a longitudinal sectional view of this embodiment in which the mounting plate is in the uppermost position in the standard mode. FIG. 5 is a cross-sectional view taken along line VV in FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. FIG. 7 is a schematic diagram illustrating the relationship between the main parts in FIG. FIG. 8 is a schematic diagram illustrating the relationship between the main parts when the mounting plate is in the intermediate position in the standard mode. FIG. 9 is a longitudinal sectional view of the present embodiment in which the mounting plate is in the lowest position in the standard mode. FIG. 10 is a schematic diagram illustrating the relationship between the main parts in FIG. FIG. 11 is a longitudinal sectional view of this embodiment in which the mounting plate is in the uppermost position in the lightweight mode. FIG. 12 is a longitudinal sectional view of this embodiment in which the mounting plate is in the lowest position in the lightweight mode. FIG. 13 is a longitudinal sectional view of this embodiment in which the mounting plate is in the uppermost position in the weight mode. FIG. 14 is a longitudinal sectional view of this embodiment in which the mounting plate is in the lowest position in the weight mode.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the accompanying drawings, similar components are denoted by the same reference numerals throughout the present specification.

  1 to 3 schematically show an article support device 1 which is a preferred embodiment of a load support mechanism according to the present invention. As shown in the figure, the article support device 1 according to this embodiment includes a base member 2, a support member 3, a spring member 4 including a compression coil spring, a spring force transmission member 5, a cam member 6, and a cam follower. Member 7.

  The base member 2 is integrally provided at the lower end of the fixed column 8 in order to install the article support device 1 on the floor surface or work table surface, and a rectangular cylindrical fixed column 8 that extends vertically and opens upward. And a base plate 9. A pair of relatively large openings 10 extending in the longitudinal direction of the fixed column 8 are formed at opposite positions on the pair of opposing side surfaces 8 a of the fixed column 8.

  The support member 3 includes a rectangular cylindrical movable column 11 that extends vertically and opens downward, and a mounting plate 12 that is integrally provided at the upper end of the movable column 11 for mounting a desired article. Have. In the center of the upper surface of the mounting plate 12, a positioning pin 13 is provided for positioning the article. A pair of first cam grooves 14 having the same shape and dimensions extending over substantially the entire width of the movable column 11 are formed obliquely with respect to the longitudinal direction of the movable column 11 on the pair of opposing side surfaces 11a of the movable column 11. It is formed at the facing position. Each first cam groove 14 has a downward cam surface 15 formed of an inner peripheral upper end surface that is linearly inclined at a predetermined angle with respect to the central axis of the movable column 11.

  The spring force transmission member 5 includes a short octagonal cylindrical slide portion 16 extending vertically and opening downward, and a pair of cams 17 having the same shape and size provided integrally at the upper end of the slide portion. Have The cam 17 is a flat plate cam that is arranged in mirror symmetry with respect to the central axis of the slide portion, in parallel with each other and a pair of opposing side surfaces 16 a of the slide portion 16. Each cam 17 has an upward cam surface 18 that extends over substantially the entire width of the slide portion 11 and has an upper end surface that is linearly inclined at a predetermined angle with respect to the central axis of the slide portion.

  As shown in FIGS. 4 and 5, the spring force transmission member 5 is in sliding contact with the inner surface of the inner hole 11 b adjacent to the outer surface adjacent to the slide portion 16 in the inner hole 11 b of the movable column 11 of the support member 3. And is slidably inserted in the vertical direction. The spring force transmission member 5 is arranged so that each cam 17 and the corresponding first cam groove 14 of the movable column are on the same side with respect to the central axis of the movable column 11. At this time, the downward cam surface 15 and the upward cam surface 18 are disposed so as to face each other with their inclination directions reversed.

  The cam member 6 has a pair of cam plates 19 having the same shape and size disposed in parallel and facing each other at a predetermined interval. Both cam plates 19 are integrally formed in a U-shape when viewed from above in the drawing by a connecting plate 20 at the upper side edge on one side thereof. Each cam plate 19 is formed with a second cam groove 21 of the same shape and size extending in the vertical direction at the opposing position. The second cam groove 21 has a lateral cam surface 22 composed of an end surface on the left side in FIG. 4, that is, the side facing the upward cam surface 18 and the downward cam surface 15. The lateral cam surface 22 is curved in a convex shape toward the right in the drawing, that is, toward the upward cam surface 18 and the downward cam surface 15 so that the inclination in the tangential direction changes over the entire length from the upper end to the lower end or partially. doing.

  In the vicinity of the lower end of each cam plate 19, a cam position adjusting groove 23 having a downward convex arc shape extending in the width direction is formed, and a scale 24 is attached to the lower side along the groove. Further, a shaft hole 25 for pivotally supporting the cam member 6 is formed at the upper end of the side edge of each cam plate 19 opposite to the connecting plate 20.

  The cam follower member 7 is made of, for example, a straight circular rod made of metal, and a plurality of rolling bearings having the same outer diameter are fitted on the outer periphery thereof along the axial direction of the rod. As a result, the cam follower member 7 can smoothly roll by bringing the bearings into contact with the upward cam surface 18, the downward cam surface 15, and the lateral cam surface 22, as will be described later. In another embodiment, the bearing can be omitted.

  The spring member 4 is disposed in the inner hole 8b of the fixing column 8 of the base member 2, and the lower end thereof is fixed in contact with the bottom surface of the inner hole. The movable column 11 having the spring force transmission member 5 mounted in the inner hole 11b is inserted into the inner hole 8b of the fixed column 8 so as to be relatively movable in the vertical direction. A spring force transmitting member 5 is mounted on the upper end of the spring member 4 so that the upper end is abutted against the upper end surface of the inner hole 15a of the slide portion 15 and is urged upward.

  A pair of left and right guide rollers 26 are provided at the upper end of the fixed column 8 so as to abut on another pair of opposite side surfaces 11 b orthogonal to the side surface 11 a provided with the first cam groove 14 of the movable column 11. ing. Further, guide rollers 27 are provided at the respective corners at the lower end of the movable column 11 so as to contact the inner surface of the inner hole 8b of the fixed column 8 adjacent to the side surface 11b. The movable column 11 is supported from both sides in the left-right direction by the fixed column 8 via these guide rollers 26, 27, so that it can be smoothly moved in the vertical direction without rattling or displacing from the left and right with respect to the fixed column. Can move.

  As shown in FIG. 3, the cam member 6 covers the fixed column 8 from the side so that the cam plate 19 overlaps each side surface 8 a provided with the opening 10 of the fixed column. The pivot pins 28 are respectively inserted through the pivot columns 28 and screwed into the screw holes at the upper end of the fixed column 8. Thereby, the cam member 6 is hold | maintained so that rocking | fluctuation centering | focusing on the said pivot pin is shown as an imaginary line in FIG. Further, a positioning screw 29 is inserted into the cam member 6 from the outside into the cam position adjusting groove 23 and screwed to a cam plate fixing portion 30 protruding from the side surface 8a of the fixing column 8 behind the cam screw. By tightening the positioning screw 29, the cam member 6, that is, each cam plate 19, is fixed to the fixed column 8 at a desired rotational position.

  In this embodiment, three numbers 1.5, 2, and 2.5 are marked on the lower scale 24 of the cam position adjusting groove 23, and the load of the article that can be placed on the article support device 1 is determined. , In the range of 1.5 to 2.5 kg. In the embodiment of FIG. 4, the set screw 29 is set to the number “2” on the scale 24 and set to support an article having a load of 2 kg. When the load of the article is 1.5 kg, the cam plate 19 is arranged at a position indicated by an imaginary line 19 ′ in FIG. 1, and when the load of the article is 2.5 kg, the cam plate 19 is rotated to a position indicated by an imaginary line 19 ″. Fixed.

  The cam follower member 7 is horizontally disposed above the cam 17 through the first cam groove 14, the second cam groove 22 and the opening 10 of the fixed column 8, and its outer peripheral surface is a downward cam surface 15 and an upward cam surface. 18 and the lateral cam surface 22 are mounted. At this time, the rolling bearing fitted to the rod of the cam follower member 7 is rolling bearing 71 with respect to the downward cam surface 15, rolling bearing 72 with respect to the upward cam surface 18, and rolling with respect to the lateral cam surface 22. Each of the bearings 73 is disposed and is individually brought into contact with the corresponding cam surface. Moreover, it is preferable to attach an appropriate retaining ring to both ends of the cam follower member 7 protruding from the second cam groove 22 to the outside of the cam plate 19 to prevent the cam follower member 7 from coming off.

  In the present embodiment, the vertical movement range of the cam follower member 7 in the second cam groove 21 is the vertical stroke of the support member 3, that is, the mounting plate 12. Within this range, the article A on the mounting plate 12 can be lifted, stopped at a desired height position, and held at that position.

  The article support device 1 includes a drive device 31 for moving the support member 3 up and down relative to the base member 2. The drive device 31 includes a drive motor 32 and a drive force transmission mechanism that transmits the drive force to the movable column 11 of the support member 3. As shown in FIG. 2, the drive motor 32 is attached to the upper end of the side surface of the fixed column 8 on the opposite side of the connecting plate 20 of the cam member 6 using an attachment stay 33.

  The driving force transmission mechanism includes a rack 34 that is integrally provided along one side surface of the movable column 11, and a pinion 35 that meshes with the rack and is pivotally supported by a mounting stay 33. Is done. The rack 34 extends vertically from the vicinity of the upper end of the movable column 11 to a position that meshes with the pinion 35 when the mounting plate 12 is at the uppermost position as shown in FIG. The pinion 35 meshes with a drive gear 36 attached to the tip of the rotation shaft of the drive motor 32. The drive motor 32 is connected to an external power source 37 by a power cable 38. In another embodiment, a built-in battery can be used in place of the power source 37.

  A first elevating switch 39 is provided on the side surface of the movable column 11 for on / off control of the drive motor 32. The first raising / lowering switch 39 has an ascending button 40a and a descending button 40b. Further, a second lift switch 41 is provided on the lower side of the mounting plate 12. The second raising / lowering switch 41 has one switch lever 42 that extends horizontally from the switch box and can be raised and lowered at the tip.

  Next, the operation and function of the article support apparatus 1 will be described. In the following description, a standard mode is set when the load of an article supported by the article support device is 2 kg, a light mode is set when the minimum use load is 1.5 kg, and a weight mode is set when the maximum use load is 2.5 kg.

  Further, the lateral cam surface 22 of the second cam groove 21 is divided into the following three regions depending on the contact position with the cam follower member 7. The first region S1 is a region in which the normal direction at the contact point with the cam follower member 7 is upward with respect to the horizontal direction. The second region S2 is a region in which the normal direction at the contact point with the cam follower member is substantially horizontal. In other words, the second region S2 is a region in which the tangential direction at the contact point with the cam follower member is substantially vertical. Here, “substantially” is slightly upward or downward from the complete horizontal direction, but the degree thereof is negligible in terms of the operational effect of the present invention or the operation or function of the article support device 1 of the present embodiment. It is meant to include a case that can be regarded as being in the horizontal direction. The third region S3 is a region in which the normal direction at the contact point with the cam follower member 7 is downward with respect to the horizontal direction.

  FIG. 4 shows a case where the placing plate 12 on which the article A having a load W is placed in the uppermost position in the standard mode. The cam follower member 7 is stationary at the upper limit position of the first region S1 of the lateral cam surface 22.

  FIG. 7 schematically shows an equilibrium state of forces acting on a system including the cam follower member 7, the fixed column 8, the movable column 11, the spring force transmission member 5, and the cam plate 19 at the upper limit position. In order to simplify the description, the load of the support member 3 and the spring force transmission member 5 and the frictional force between the movable column 11 and the fixed column 8 and the spring force transmission member are omitted. In an actual design, it goes without saying that these factors must be taken into consideration, and the load of the support member and the spring force transmission member is composed of the cam follower member, the fixed column, the movable column, the spring force transmission member, and the cam plate. In addition to the force acting on the system, the resultant force is a friction force generated between the movable column, the fixed column, and the spring force transmission member, and in some cases, friction or resistance generated in or by the drive unit 31. If it is smaller, the equilibrium state is maintained.

  Here, the spring force Fs of the spring member 4 composed of a compression coil spring having a spring constant k is expressed by the displacement x in the axial direction of the compression coil spring (displacement from the free length of the spring, that is, the length of the unloaded state: Fs = k · x. In order to be able to support the article A at the uppermost position, at the upper limit position of the stroke, the compression coil spring is pre-compressed by a predetermined initial displacement amount x0 from the free length, and already has an initial spring force (Fs0 = k -It is configured to exhibit x0). This is the same when the cam plate 19 is rotated to change its fixed position in accordance with the load to be supported.

  In FIG. 7, at the contact point Pa between the cam follower member 7 and the downward cam surface 15, the load W of the article A, the reaction force Ra acting in the normal direction of the downward cam surface 15 from the cam follower member 7, and the movable column 8 are movable. The horizontal reaction force Rd1 acting on the column 11 is balanced. The magnitude of the vertical component Ra1 of the reaction force Ra is equal to the magnitude of the load W, and the magnitude of the horizontal component Ra2 is equal to the reaction force Rd1 from the fixed column 8. A force Fa that presses the cam follower member 7 from the downward cam surface 15 is a resultant force of the load W and the reaction force Rd1.

  At the contact Pb between the cam follower member 7 and the upward cam surface 18, the spring force Fs of the spring member 4, the reaction force Rb acting in the normal direction of the upward cam surface 18 from the cam follower member 7, and the movable column 11 from the fixed column 8. The reaction force Rd2 acting in the horizontal direction on the spring force transmission member 5 is balanced via the. The magnitude of the vertical component Rb1 of the reaction force Rb is equal to the spring force Fs, and the magnitude of the horizontal component Rb2 is equal to the reaction force Rd2 of the fixed column 8. The force Fb that presses the cam follower member 7 from the upward cam surface 18 is a resultant force of the spring force Fs and the reaction force Rd2.

  At the contact point Pc between the cam follower member 7 and the lateral cam surface 22, forces Fa and Fb acting on the cam follower member 7 from the downward cam surface 15 and the upward cam surface 18, and a reaction force Rc acting from the lateral cam surface 22 in the normal direction. And are in equilibrium. Since the cam follower member 7 is in the first region S1 of the lateral cam surface 22, the reaction force Rc has an upward vertical component Rc1. The magnitude of the horizontal component Rc2 of the reaction force Rc is the sum of the reaction force Rd1 and the reaction force Rd2 that the movable column 11 and the spring force transmission member 5 receive from the fixed column 8.

When the cam follower member 7 is stationary at a certain position on the lateral cam surface 22, the force acting direction is positive in the vertical direction between the load W, the spring force Fs, and the vertical component Rc1 of the reaction force Rc. The following relationship always holds in theory.
W + Fs + Rc1 = 0
In the actual design, friction and resistance are generated between the members as described above, and even if the resultant force expressed by this relational expression is not 0 and has a slight value, the resultant force is not limited to the friction and the friction. If it is smaller than the resistance, the equilibrium state is maintained.

  In the case of FIG. 4, the spring force Fs of the spring member 4 is the minimum initial spring force (Fs0 = k · x0), which is smaller than the load W. Accordingly, the vertical force component Rc1 of the reaction force Rc acting upward from the lateral cam surface 22 is applied as an assist force to the spring force Fs, thereby realizing the balance with the load W in the vertical direction. In this state, when a downward force is applied to the article A or the mounting plate 12, the force is added to the load W and the balance is lost. Therefore, the article can be easily lowered even with a relatively small force. .

  When the mounting plate 12 is lowered, the cam follower member 7 moves downward while being displaced in the left-right direction along the lateral cam surface, the downward cam surface, and the upward cam surface. While the cam follower member 7 is in the range of the first region S1 of the lateral cam surface 22, the upward vertical component Rc1 of the reaction force Rc acts to balance the spring force Fs with the load W.

  In this embodiment, the mounting plate 12 on which the article A is placed can be lowered by turning on the driving motor 32 and driving the movable column 11 downward. The drive motor 32 can be turned on / off from either the first lift switch 39 or the second lift switch 41.

  As the first elevating switch 39, for example, a pressure sensitive switch that is energized only while the ascending button 40a or the descending button 40b is being pressed and the resistance value of the contact changes continuously with the pressing force can be used. In this case, while the lowering button is pressed, the drive motor 32 is turned on, rotates counterclockwise as indicated by an arrow in FIG. 6, and the mounting plate 12 is lowered. When the lowering button is released, the drive motor is turned off, and the mounting plate can be stopped at that position. Further, if the lowering button 40b is pressed strongly, the rotational speed of the drive motor increases and the mounting plate 12 descends quickly. Conversely, if the lowering button is lightly pressed, the rotational speed of the drive motor is low, and the mounting plate 12 is slowly lowered.

  The second raising / lowering switch 41 can be of a type that uses a strain gauge or a resistance sheet, for example, to detect the direction of raising and lowering the switch lever 42 and the amount of strain, and to control the drive motor 32 based on the detected direction. While the switch lever 42 is pushed down, the drive motor 32 is turned on, rotates counterclockwise as indicated by an arrow in FIG. 6, and the mounting plate 12 descends. When the switch lever is released and returned to the original horizontal position, the drive motor is turned off, and the mounting plate can be stopped at that position. Further, if the force for pushing down the switch lever 42 is strong, the rotational speed of the drive motor increases and the mounting plate 12 descends quickly. On the contrary, if the switch lever is lightly pressed down, the rotational speed of the drive motor is low, and the mounting plate 12 is slowly lowered.

  Commercially available switches can be widely used for the first lift switch 39 and the second lift switch 41. Further, the up / down switch merely turns on and off the drive motor and does not have to be able to control the rotation speed. Further, the lift switch can be provided with a lock function so that it cannot be operated by mistake.

  As described above, since the mounting plate 12 on which the article A is placed can be moved with a relatively small force, the output of the drive motor 32 may be relatively small according to the magnitude of the load W. Therefore, it is easy to reduce the size of the article support device 1.

  Further, if the drive motor 32 is equipped with an electromagnetic brake, even if an external force is applied to the article A or the mounting plate 12, it does not rotate easily, so that the mounting plate 12 can be safely moved to a desired height position. Can be held in. If the drive motor 32 does not have such a braking function, the mounting plate 12 can be pushed down by hand.

  The spring force Fs of the spring member 4 increases as the displacement of the compression coil spring increases as the spring force transmission member 5 moves downward due to being pressed by the cam follower member 7. As the spring force Fs increases, the assist force due to the vertical component Rc1 of the reaction force Rc from the lateral cam surface 22 can be reduced. Therefore, the inclination with respect to the vertical direction of the tangential direction of the lateral cam surface 22 also decreases as it goes downward.

  As the force with which the cam follower member 7 presses the lateral cam surface 22 in the horizontal direction by the pressing force from the downward cam surface 15 and the upward cam surface 18 increases, the horizontal component Rc2 of the reaction force Rc increases. The vertical component Rc1 becomes large. The reaction force Rd1 and the reaction force Rd2 increase when the inclination of the downward cam surface 15 and the upward cam surface 18 with respect to the vertical direction is reduced, and decrease when the inclination is increased. By adjusting the inclination of the downward cam surface 15 and the upward cam surface 18 with respect to the vertical direction, an appropriate pressing force with respect to the lateral cam surface 22 can be obtained.

  In other words, the reaction force Rc of the lateral cam surface 22 is the same in the vertical direction even if the inclination of the lateral cam surface with respect to the vertical direction is reduced if the horizontal pressing force against the lateral cam surface is large. The upward assist force in the vertical direction to the component Rc1, that is, the spring force Fs is obtained. The lateral cam surface 22 can be designed to have a laterally convex shape that is looser, that is, less curved, as the inclination with respect to the vertical direction becomes smaller.

  Conversely, the horizontal cam surface 22 can be pushed horizontally by increasing the inclination of the downward cam surface 15 and / or the upward cam surface 18 with respect to the vertical direction or omitting one of the downward cam surface 15 or the upward cam surface 18. As the pressure decreases, the reaction force Rc of the lateral cam surface 22 decreases accordingly. Here, in order to obtain the upward vertical component Rc1 having the same size, the inclination of the lateral cam surface 22 with respect to the vertical direction must be increased, and the laterally convex shape having a tighter curve, that is, a larger curvature.

  In the standard mode, when the mounting plate 12 on which the article A having the load W is placed is lowered from the uppermost position in FIG. 4 to the intermediate position, the cam follower member 7 is set to the lateral cam surface 22 as indicated by an imaginary line in FIG. It is located within the range of the second region S2. FIG. 8 schematically shows an equilibrium state of forces acting on a system including the cam follower member 7, the fixed column 8, the movable column 11, the spring force transmission member 5, and the cam plate 19 at this intermediate position. Similarly, for simplification, the load of the support member 3 and the spring force transmission member 5 and the frictional force between the movable column 11 and the fixed column 8 and the spring force transmission member will be omitted.

  As in the case of FIG. 7, at the contact point Pa between the cam follower member 7 and the downward cam surface 15, the load W of the article A, the reaction force Ra acting in the normal direction of the downward cam surface 15 from the cam follower member 7, and the fixed The horizontal reaction force Rd1 acting on the movable column 11 from the column 8 is balanced. The magnitude of the vertical component Ra1 of the reaction force Ra is equal to the load W, and the magnitude of the horizontal component Ra2 is equal to the reaction force Rd1 of the fixed column 8. A force Fa acting on the cam follower member 7 from the downward cam surface 15 is a resultant force of the load W and the reaction force Rd1.

  At the contact Pb between the cam follower member 7 and the upward cam surface 18, the spring force Fs of the spring member 4, the reaction force Rb acting in the normal direction of the upward cam surface 18 from the cam follower member 7, and the movable column 11 from the fixed column 8. The horizontal reaction force Rd2 acting on the spring force transmission member 5 is balanced. The magnitude of the vertical component Rb1 of the reaction force Rb is equal to the spring force Fs, and the magnitude of the horizontal component Rb2 is equal to the reaction force Rd2 of the fixed column 8. A force Fb acting on the cam follower member 7 from the upward cam surface 18 is a resultant force of the spring force Fs and the reaction force Rd2.

  At the contact point Pc between the cam follower member 7 and the lateral cam surface 22, forces Fa and Fb acting on the cam follower member 7 from the downward cam surface 15 and the upward cam surface 18, and a reaction force Rc acting from the lateral cam surface 22 in the normal direction. And are in equilibrium. In this case, since the cam follower member 7 is in the second region S2 of the lateral cam surface 22, the reaction force Rc is substantially only the horizontal component and has no vertical component. The magnitude of the reaction force Rc is the sum of the reaction force Rd1 and the reaction force Rd2 acting on the movable column 11 and the spring force transmission member 5 from the fixed column 8.

  Thus, when the cam follower member 7 is located in the range of the second region S2 of the lateral cam surface 22, the spring force Fs and the load W of the spring member 4 are substantially balanced in the vertical direction. Therefore, the spring force Fs does not require an assist force due to the reaction force Rc from the lateral cam surface 22. Even in this state, by simply turning on the drive motor 32 and applying a relatively small driving force, the force is added to the load W or the spring force Fs and the balance is lost. Can be moved up and down.

  In this embodiment, when the placement plate 12 on which the article A is placed is raised, the drive motor 32 may be turned on to drive the movable column 11 upward. The drive motor 32 can be turned on / off from either the first lift switch 39 or the second lift switch 41.

  The drive motor 32 is in an ON state while the lift button 40a of the first lift switch 39 is being pressed, and rotates in the clockwise direction in FIG. When the raising button is released, the drive motor is turned off, and the mounting plate can be stopped at that position. Further, if the ascending button 40a is pressed strongly, the rotational speed of the drive motor increases and the mounting plate 12 rises quickly. On the contrary, if the raising button is lightly pressed, the rotational speed of the drive motor is low, and the mounting plate 12 rises slowly.

  Further, the drive motor 32 is turned on while the switch lever 42 of the second elevation switch 41 is being pushed up, and similarly rotates clockwise in FIG. 6, and the mounting plate 12 is raised. When the switch lever is released and returned to the original horizontal position, the drive motor is turned off, and the mounting plate can be stopped at that position. Further, if the force for pushing down the switch lever 42 is strong, the rotational speed of the drive motor increases and the mounting plate 12 rises quickly. On the contrary, if the switch lever is lightly pushed up, the rotational speed of the drive motor is low, and the mounting plate 12 is slowly raised.

  FIG. 9 shows a case where the placing plate 12 on which the article A having the load W is lowered in the standard mode. The cam follower member 7 is stationary at the lower limit position of the third region S3 of the lateral cam surface 22.

  FIG. 10 schematically shows an equilibrium state of forces acting on a system including the cam follower member 7, the fixed column 8, the movable column 11, the spring force transmission member 5, and the cam plate 19 at the lower limit position. Similarly, for simplification, the load of the support member 3 and the spring force transmission member 5 and the frictional force between the movable column 11 and the fixed column 8 and the spring force transmission member will be omitted.

  In the figure, at the contact point Pa between the cam follower member 7 and the downward cam surface 15, the load W of the article A, the reaction force Ra acting in the normal direction of the downward cam surface 15 from the cam follower member 7, and the movable column 8 are movable. The reaction force Rd1 acting in the horizontal direction on the column 11 is balanced. The magnitude of the vertical component Ra1 of the reaction force Ra is equal to the load W, and the magnitude of the horizontal component Ra2 is equal to the reaction force Rd1 of the fixed column 8. A force Fa that presses the cam follower member 7 from the downward cam surface 15 is a resultant force of the load W and the reaction force Rd1.

  At the contact Pb between the cam follower member 7 and the upward cam surface 18, the spring force Fs of the spring member 4, the reaction force Rb from the cam follower member 7 in the normal direction of the upward cam surface 18, and the movable column 11 from the fixed column 8. The reaction force Rd2 acting in the horizontal direction on the spring force transmission member 5 is balanced. The magnitude of the vertical component Rb1 of the reaction force Rb is equal to the spring force Fs, and the magnitude of the horizontal component Rb2 is equal to the reaction force Rd2 of the fixed column 8. The force Fb that presses the cam follower member 7 from the upward cam surface 18 is a resultant force of the spring force Fs and the reaction force Rd2.

  At the contact point Pc between the cam follower member 7 and the lateral cam surface 22, forces Fa and Fb acting on the cam follower member 7 from the downward cam surface 15 and the upward cam surface 18, and a reaction force Rc acting from the lateral cam surface 22 in the normal direction. And are in equilibrium. Since the cam follower member 7 is in the third region S3 of the lateral cam surface 22, the reaction force Rc has a downward vertical component Rc1. The magnitude of the horizontal component Rc2 of the reaction force Rc is the sum of the reaction force Rd1 and the reaction force Rd2 that the movable column 11 and the spring force transmission member 5 receive from the fixed column 8.

  In the case of FIG. 9, the displacement of the spring member 4 is maximum, the spring force Fs is maximum, and the magnitude thereof is larger than the load W. Therefore, the vertical component Rc1 of the reaction force Rc acting downward from the lateral cam surface 22 acts in a direction to reduce the upward biasing force, that is, the push-up force by the spring force Fs. The equilibrium is realized.

  Even in this state, the article A or the mounting plate 12 simply turns on the drive motor 32 as described above to apply a relatively small driving force, and the force is added to the spring force Fs, so that the equilibrium is lost. Can be raised easily. When the mounting plate 12 is raised, the cam follower member 7 moves upward while being displaced in the left-right direction along the lateral cam surface 22, the downward cam surface 15, and the upward cam surface 18. While the cam follower member 7 is within the range of the third region S3 of the lateral cam surface 22, the downward vertical component Rc1 of the reaction force Rc reduces the push-up force due to the spring force Fs of the spring member 4 and balances with the load W. Acts in the direction.

  The spring force Fs of the spring member 4 decreases in response to the spring force transmission member 5 moving upward against the cam follower member 7 and the displacement of the compression coil spring being reduced. Accordingly, the vertical component Rc1 of the reaction force Rc from the cam plate 19 can be reduced. Therefore, the inclination with respect to the vertical direction of the tangential direction of the lateral cam surface 22 also decreases as it goes upward.

  Also in the third region S3, the horizontal component Rc2 of the reaction force Rc increases as the force with which the cam follower member 7 presses the lateral cam surface 22 in the horizontal direction by the pressing force from the downward cam surface 15 and the upward cam surface 18 increases. Accordingly, the reaction force Rc and its vertical component Rc1 are increased. Similarly, the reaction force Rd1 and the reaction force Rd2 increase when the inclination of the downward cam surface 15 and the upward cam surface 18 with respect to the vertical direction is reduced, and decrease when the inclination is increased. By adjusting the inclination of the downward cam surface 15 and the upward cam surface 18 with respect to the vertical direction, an appropriate pressing force with respect to the lateral cam surface 22 can be obtained.

  In other words, the reaction force Rc of the lateral cam surface 22 is the same in the vertical direction even if the inclination of the lateral cam surface with respect to the vertical direction is reduced if the horizontal pressing force against the lateral cam surface is large. The component Rc1, that is, a vertically downward force that reduces the pushing force, is obtained. The lateral cam surface 22 can be designed to have a laterally convex shape that is looser, that is, less curved, as the inclination with respect to the vertical direction becomes smaller.

  Conversely, the horizontal cam surface 22 can be pushed horizontally by increasing the inclination of the downward cam surface 15 and / or the upward cam surface 18 with respect to the vertical direction or omitting one of the downward cam surface 15 or the upward cam surface 18. As the pressure decreases, the reaction force Rc of the lateral cam surface 22 decreases accordingly. Here, in order to obtain the downward vertical direction component Rc1 having the same size, the inclination of the lateral cam surface 22 with respect to the vertical direction must be increased, and the laterally convex shape having a tighter curve, that is, a larger curvature.

  When the lateral cam surface 22 is viewed as a whole, the cam follower member 7 sets the force for pressing the lateral cam surface 22 in the horizontal direction to an appropriate magnitude by the downward cam surface 15 and the upward cam surface 18 inclined with respect to the vertical direction. By doing so, it is possible to obtain a laterally convex shape having a gentle or small curvature through the first to third regions S1 to S3 while securing a necessary and sufficient vertical component Rc1. Accordingly, the horizontal dimension of the second cam groove 21 and the cam plate 19 can be made relatively small, and the article support device 1 itself can be downsized. Further, as shown in FIG. 1, when the cam member 6 is pivoted about the pivot pin 28, it is advantageous because the protrusion from the fixed column 8 to the side can be reduced.

  According to this embodiment, when the drive device 31 is stopped, the system comprising the cam follower member 7, the fixed column 8, the movable column 11, the spring force transmission member 5, and the cam plate 19 in the entire region of the lateral cam surface 22. The load W of the article A, the spring force Fs of the spring member 4, the reaction force from the fixed column 8, and the reaction force from the cam plate 19 are balanced around the cam follower member 7. As a result, the mounting plate 12 on which the article A is placed can be held at a desired height position in the range of the vertical stroke, and the position can be maintained, and the drive motor 32 having a relatively small output can be easily used. Can be moved up and down.

  In practice, when the mounting plate 12 is moved up and down, a resistance such as friction is generated between the movable column 11, the fixed column 8, and the spring force transmission member 5, which are omitted in the above description. In this embodiment, the resistance due to friction between the movable column 11 and the fixed column 8 is reduced by the guide roller 26 provided at the upper end of the fixed column 8 and the guide roller 27 provided at each corner of the lower end of the movable column 11. And the influence which it may have on the raising / lowering operation | movement of the mounting plate 12 is eliminated or eased, and smooth operation is ensured.

  11 and 12 show the article support device 1 set to the lightweight mode. The lightweight mode is set by rotating the cam plate 19 around the pivot pin 28 in the clockwise direction in the drawing, and tightening and fixing the set screw 29 in accordance with the numeral “1.5” of the scale 24. As in the case of the standard mode in FIG. 4, the lateral cam surface 22 has a first region S1 in which the normal direction at the contact point with the cam follower member 7 is upward in the horizontal direction, and the first tangential direction is substantially vertical. It is divided into two regions S2 and a third region S3 whose normal direction is downward with respect to the horizontal direction.

  FIG. 11 shows a case where the placement plate 12 on which the article A is placed is at the uppermost position. The cam follower member 7 is stationary at the upper limit position of the first region S1 of the lateral cam surface 22. At this position, with the drive device 31 stopped, the system comprising the cam follower member 7, the fixed column 8, the movable column 11, the spring force transmission member 5 and the cam plate 19 includes the load W of the article A, the spring member. The spring force Fs 4, the reaction force from the fixed column 8, and the reaction force from the cam plate 19 act and balance around the cam follower member 7.

  In the first region S1, the displacement of the spring member 4 is small and the spring force Fs is smaller than the load W of the article A as described in connection with FIG. The reaction force Rc acting on the cam follower member 7 from the lateral cam surface 22 includes an upward vertical component. By applying the upward vertical component of the reaction force Rc as an assist force to the spring force Fs, the balance with the load W is realized in the vertical direction.

  When the placement plate 12 on which the article A is placed is lowered from the uppermost position in FIG. 11 to the intermediate position, the cam follower member 7 is within the range of the second region S2 of the lateral cam surface 22 as indicated by an imaginary line in FIG. Located in. Even in this intermediate position, with the drive device 31 stopped, the system comprising the cam follower member 7, the fixed column 8, the movable column 11, the spring force transmission member 5, and the cam plate 19 includes the load W of the article A, the spring The spring force Fs of the member 4, the reaction force from the fixed column 8, and the reaction force from the cam plate 19 act and balance around the cam follower member 7.

  In the second region S2, as described with reference to FIG. 8 for the standard mode, the reaction force Rc from the lateral cam surface 22 is substantially only the horizontal component and has no vertical component. In the vertical direction, the spring force Fs of the spring member 4 and the load W are substantially balanced.

  FIG. 12 shows a case where the placement plate 12 on which the article A is placed is at the lowest position. The cam follower member 7 is stationary at the lower limit position of the third region S3 of the lateral cam surface 22. Even at this position, with the driving device 31 stopped, the system comprising the cam follower member 7, the fixed column 8, the movable column 11, the spring force transmitting member 5 and the cam plate 19 includes the load W of the article A, the spring member. The spring force Fs 4, the reaction force from the fixed column 8, and the reaction force from the cam plate 19 act and balance around the cam follower member 7.

  In the third region S3, the displacement of the spring member 4 is large and the spring force Fs is larger than the load W of the article A as described in the standard mode with reference to FIG. The reaction force Rc acting on the cam follower member 7 from the lateral cam surface 22 includes a downward vertical component. The downward vertical component of the reaction force Rc acts in a direction that reduces the push-up force due to the spring force Fs, thereby realizing the balance with the load W in the vertical direction.

  13 to 14 show the article support device 1 set to the weight mode. The weight mode is set by rotating the cam plate 19 around the pivot pin 28 in the counterclockwise direction in the drawing and tightening and fixing the positioning screw 29 in accordance with the numeral “2.5” on the scale 24. As in the case of the standard mode in FIG. 4, the lateral cam surface 22 has a first region S1 in which the normal direction at the contact point with the cam follower member 7 is upward in the horizontal direction, and the first tangential direction is substantially vertical. It is divided into two regions S2 and a third region S3 whose normal direction is downward with respect to the horizontal direction.

  FIG. 13 shows a case where the placement plate 12 on which the article A is placed is at the uppermost position. The cam follower member 7 is stationary at the upper limit position of the first region S1 of the lateral cam surface 22. At this position, with the drive device 31 stopped, the system comprising the cam follower member 7, the fixed column 8, the movable column 11, the spring force transmission member 5 and the cam plate 19 includes the load W of the article A, the spring member. The spring force Fs 4, the reaction force from the fixed column 8, and the reaction force from the cam plate 19 act and balance around the cam follower member 7.

  In the first region S1, the displacement of the spring member 4 is small and the spring force Fs is smaller than the load W of the article A, as described above for the standard mode and the lightweight mode. The reaction force Rc acting on the cam follower member 7 from the lateral cam surface 22 includes an upward vertical component. By applying the upward vertical component of the reaction force Rc as an assist force to the spring force Fs, the balance with the load W is realized in the vertical direction.

  When the placing plate 12 on which the article A is placed is lowered from the uppermost position in FIG. 13 to the intermediate position, the cam follower member 7 is within the range of the second region S2 of the lateral cam surface 22 as indicated by an imaginary line in FIG. Located in. Even in this intermediate position, with the drive device 31 stopped, the system comprising the cam follower member 7, the fixed column 8, the movable column 11, the spring force transmission member 5, and the cam plate 19 includes the load W of the article A, the spring The spring force Fs of the member 4, the reaction force from the fixed column 8, and the reaction force from the cam plate 19 act and balance around the cam follower member 7.

  In the second region S2, as described above with respect to the standard mode and the light mode, the reaction force Rc from the lateral cam surface 22 is substantially only a horizontal component and has no vertical component. In the vertical direction, the spring force Fs of the spring member 4 and the load W are substantially balanced.

  FIG. 14 shows a case where the placing plate 12 on which the article A is placed is at the lowest position. The cam follower member 7 is stationary at the lower limit position of the third region S3 of the lateral cam surface 22. At this position, with the drive device 31 stopped, the system comprising the cam follower member 7, the fixed column 8, the movable column 11, the spring force transmission member 5 and the cam plate 19 includes the load W of the article A, the spring member. The spring force Fs 4, the reaction force from the fixed column 8, and the reaction force from the cam plate 19 act and balance around the cam follower member 7.

  In the third region S3, the displacement of the spring member 4 is large and the spring force Fs is larger than the load W of the article A, as described above for the standard mode and the lightweight mode. The reaction force Rc acting on the cam follower member 7 from the lateral cam surface 22 includes a downward vertical component. The downward vertical component of the reaction force Rc acts in a direction that reduces the push-up force due to the spring force Fs, thereby realizing the balance with the load W in the vertical direction.

  Comparing FIG. 11 and FIG. 12 with FIG. 4 and FIG. 9, in the lightweight mode, the first to third regions S1 to S3 as a whole are shifted upward as compared with the case of the standard mode. Therefore, the first region S1 is narrower and the third region S3 is wider than in the standard mode.

  13 and 14 are compared with FIGS. 4 and 9, in the weight mode, the first to third regions S1 to S3 as a whole are shifted downward as compared with the case of the standard mode. Therefore, the first region S1 is wider and the third region S3 is narrower than in the standard mode.

  In the lightweight mode, although the load W of the article A is smaller than that in the standard mode, the same spring member 4 as in the standard mode is used, so that the force for pushing up the article A is relatively large. Therefore, the assist force required for the spring force F to balance the load W in the vertical direction in the upper region where the displacement of the spring member 4 is small on the lateral cam surface 22 may be smaller than that in the standard mode. Furthermore, the spring force Fs and the load W can be balanced in the vertical direction without an assist force from a position above the standard mode. Conversely, in the lower region where the displacement of the spring member 4 is large, it is necessary to apply a downward force from a position higher than that in the standard mode in order to reduce the pushing force.

  On the other hand, in the weight mode, although the load W of the article A is larger than that in the standard mode, the same spring member 4 as in the standard mode is used, so the force for pushing up the article A is relatively small. Therefore, on the lateral cam surface 22, in the upper region where the displacement of the spring member 4 is small, the assist force required for the spring force Fs to balance the load W in the vertical direction is larger than that in the standard mode. Furthermore, the spring force Fs can be balanced with the load W in the vertical direction without any assist force at a position below that in the standard mode. On the contrary, in the lower region where the displacement of the spring member 4 is large, the downward force for reducing the push-up force may be smaller than that in the standard mode.

  In this embodiment, the cam plate 19 is rotated as described above to change the orientation of the entire lateral cam surface 22 relative to the cam follower member 7, thereby reducing the light mode or weight without replacing the cam plate or cam member 6. Corresponding to the mode, the first to third regions S1 to S3 are shifted upward or downward as shown in FIG. 11 or FIG. Moreover, the cam profile of the lateral cam surface 22 is designed so that the mounting plate 12 on which the article is placed can be stopped at a desired height in all the areas even if the first to third areas S1 to S3 are shifted. Is formed.

  The above description is made for the case where the load W of the article is 1.5 kg, 2 kg, and 2.5 kg in the present embodiment. However, the present embodiment is naturally an article that can be placed on the article support device 1. It can be similarly applied in the load range. The side-facing cam surface 22 is designed to have a cam profile that can rest the mounting plate 12 on which articles are placed at a desired height in the entire area when the cam plate 19 is fixed at a predetermined position according to the load to be supported. Is formed.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications or changes can be made within the technical scope. For example, the downward cam surface of the movable column and the lateral cam surface of the cam plate can be formed in various known forms other than the inner peripheral edge of the cam groove described above. Further, the usable load range of the article support device 1 can be set variously, and correspondingly, the downward cam surface of the movable column, the upward cam surface of the spring force transmission member, and the lateral direction of the cam plate The cam surface can be designed for various cam profiles. In addition to the electric motor, various known driving means can be used for the driving device. Furthermore, in addition to the compression coil spring described above, the spring member has a different shape such as a leaf spring and a spiral spring, a fluid spring such as an air spring, an elastic material such as rubber, and other non-metallic materials, etc. Various known springs can be applied.

DESCRIPTION OF SYMBOLS 1 Article support apparatus 2 Base member 3 Support member 4 Spring member 5 Spring force transmission member 6 Cam member 7 Cam follower member 8 Fixed column 9 Base plate 11 Movable column 12 Mounting plate 14 1st cam groove 15 Downward cam surface 16 Slide part 17 Cam 18 upward cam surface 19 cam plate 21 second cam groove 22 lateral cam surface 23 cam position adjustment groove 31 drive device 32 drive motor 34 rack 35 pinion 39 first lift switch 41 second lift switch

Claims (3)

A support member for supporting a load, movable within a predetermined range along a predetermined direction;
A spring member having one end fixed and the other end exerting a biasing force in the direction along the moving direction of the support member against the load;
The load member and the biasing force are transmitted between the support member and the other end of the spring member, and are disposed so as to be displaced along the moving direction together with the load and the biasing force, and at a predetermined angle with respect to the direction of the biasing force. An inclined first cam surface and a cam follower contacting the first cam surface;
A second cam surface that is inclined at a predetermined angle with respect to the direction of the urging force and is in contact with the cam follower;
A side support portion that generates a reaction force that restricts displacement of the first cam surface in a direction orthogonal to the direction of the biasing force with respect to the load and / or the biasing force;
A controllable drive mechanism for moving the support member along the moving direction;
The pressing force of the second cam surface to the cam follower includes a component in a first direction along the direction of the biasing force generated by the position of the support member within the predetermined range in which the support member can move, and at least the biasing force. A second direction component orthogonal to the direction of
The first cam surface and the second cam surface, when the drive mechanism is stopped, the load acting around the cam follower, the urging force of the spring member, the pressing force of the second cam surface to the cam follower, The load support mechanism is designed so that a reaction force of the side support portion against the first cam surface is balanced in the predetermined range in which the support member is movable.   The load support mechanism according to claim 1, wherein the drive mechanism is capable of controlling the start, stop, direction, or speed of movement of the support member.   The second cam surface can change its orientation with respect to the cam follower corresponding to the load having a different size, and the first cam surface and the second cam surface are the cam follower of the second cam surface. 3. The load support mechanism according to claim 1, wherein the load support mechanism is provided so that an equilibrium state of the force acting around the cam follower can be maintained even if the direction of the cam follower is changed.

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