JP2015075232A - Load support mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a mechanism for displaceably supporting articles of various weights on desired positions with a small and light-weight structure.SOLUTION: A load support mechanism 1 includes a fixing portion 2, a movable supporting portion 3 for supporting a load, a spring 4 arranged in parallel with the moving direction of the supporting portion, a spring force transmitting portion 5, first and second movable cams 6, 7, a fixed cam 8, a cam follower 9, and first and second side supporting portions. The cam follower is pressed to the first and second movable cams and the fixed cam by a load of an article and a spring force of the spring. A pressing force to the cam follower, of the fixed cam includes a vertical component according to a height position of the supporting portion, and the vertical component compensates or eliminates the force of the spring to press up the load. Each of the cams is designed so that the load, the spring force and the pressing force to the cam follower from each of the cams, acting around the cam follower, are balanced.

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, there is known a monitor device support mechanism 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.

  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 and can be easily reduced in size.

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;
One end is fixed, the other end resists the load and exerts a biasing force in the direction along the moving direction of the supporting member, and a spring member disposed on one side with respect to the moving direction of the supporting member;
With cam followers,
It inclines at a predetermined angle with respect to the direction of the urging force, abuts on a cam follower, transmits the load and urging force between the support member and the other end of the spring member, and is displaced along the moving direction together with them. A movable cam surface;
A fixed cam surface that is inclined at a predetermined angle with respect to the direction of the biasing force and abuts the cam follower;
A side support portion that generates a reaction force that regulates displacement in a direction orthogonal to the direction of the biasing force on the movable cam surface with respect to the load and / or the biasing force,
The pressing force of the fixed cam surface to the cam follower is orthogonal to the direction of the urging force at least in the first direction along the direction of the urging force generated by the position of the support member within the predetermined range in which the support member can move. A second direction component to
The load that the movable cam surface and the fixed cam surface act around the cam follower, the biasing force of the spring member, the pressing force of the fixed cam surface to the cam follower, and the reaction force of the side support portion to the movable cam surface are the support members. It is designed so that it may balance in the predetermined range which 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.

  Further, when the load supporting mechanism of the present invention is realized in an actual apparatus by arranging the spring member on one side with respect to the moving direction of the supporting member, for example, in parallel with the supporting member, the depth or other dimensions of the spring supporting member is realized. Can be designed smaller. As a result, it is possible to effectively reduce the size of the apparatus, which is particularly advantageous when supporting panel-like articles such as a television monitor.

  In one embodiment, each of the plurality of support mechanisms includes a support member, a spring member, a cam follower, a movable cam surface, a fixed cam surface, and a side support portion. It is common. Thereby, since the load of a load is disperse | distributed to a some support mechanism, it becomes easy to support a bigger load and a heavier article. Further, by sharing the support member, it is possible to receive a load with a larger area, so it is possible to support a longer article or the like.

  In another embodiment, each of the first support mechanism and the second support mechanism includes a support member, a spring member, a cam follower, a movable cam surface, a fixed cam surface, and a side support portion. The member and the support member of the second support mechanism are common, and the first support mechanism and the second support mechanism are arranged symmetrically with respect to the moving direction of the support member. As a result, the common support member is supported by the first support mechanism and the second support mechanism in a balanced manner on the left and right, and the support member can be more stably held and moved.

  In another embodiment, the movable cam surface is inclined with respect to the direction of the urging force, abuts against the cam follower, and transmits the load to the spring member side. A second movable cam surface that is inclined with respect to the direction and is in contact with the cam follower and transmits the biasing force to the support member side, and the side support portion has the biasing force against the first movable cam surface. A reaction force that regulates the displacement in a direction perpendicular to the direction of the urging force with respect to the first side support portion that generates a reaction force that regulates a displacement in a direction orthogonal to the direction of And a second side support portion that generates

  The pressing force of the second cam surface to the cam follower increases as the force pressing the second cam surface in the horizontal direction from the cam follower increases. By pressing the cam follower with the first movable cam surface and the second movable cam surface, the horizontal pressing force on the second cam surface can be easily increased. As a result, the component in the first direction of the pressing force of the second cam surface to the cam follower also increases. Therefore, even if the inclination of the second cam surface with respect to the direction of the biasing force is reduced, the biasing force of the spring member is assisted. Or the power to reduce can be made the same magnitude.

  When the inclination with respect to the direction of the urging force is reduced, the second cam surface can be reduced in size in the direction perpendicular to the direction of the urging force as a whole. Therefore, the entire apparatus can be reduced in size, particularly in a direction perpendicular to the direction of the urging force.

  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 still another embodiment, the first movable cam surface and the second movable cam surface are disposed so as to be inclined in opposite directions and to face each other with the cam follower interposed therebetween. Thereby, the cam follower can be pressed with a larger force from the first movable cam surface and the second movable cam surface.

  In another embodiment, the spring member is a tension spring. Thus, the load support mechanism of the present invention can be configured with a relatively simple structure and at a lower cost.

FIG. 1 is a diagram showing a basic configuration of a load support mechanism according to the present invention. FIG. 2 is an arrow view taken along the line II-II in FIG. FIG. 3 is a diagram illustrating the relationship between the main parts in a state where the cam follower is in the first region S1 of the lateral cam surface. FIG. 4 is an explanatory view similar to FIG. 3 in which the cam follower is in the second region S2 of the lateral cam surface. FIG. 5 is an explanatory view similar to FIG. 3 in which the cam follower is in the third region S3 of the lateral cam surface. FIG. 6 is a perspective view of an embodiment of an article support apparatus to which the present invention is applied. FIG. 7 is an exploded perspective view of the embodiment of FIG. FIG. 8 is a front view of the main part with the support frame part in the uppermost position. 9 is an enlarged cross-sectional view taken along line IX-IX in FIG. FIG. 10 is a front view similar to FIG. 8 with the support frame portion in the intermediate position. FIG. 11 is a front view similar to FIG. 8 with the support frame portion in the lowest position. FIG. 12 is a partially enlarged view showing the vicinity of the upper end of the lateral cam surface. FIG. 13 is a partially enlarged view showing the vicinity of the lower end of the lateral cam surface. FIG. 14 is a partially enlarged view showing the vicinity of the upper end of the first movable cam surface. FIG. 15 is a partially enlarged view showing the vicinity of the lower end of the second movable cam surface. FIG. 16 is a partially enlarged perspective view showing the brake mechanism of the present embodiment. FIG. 17 is a front view of the brake mechanism of FIG. FIG. 18 is a front view showing the releasing operation of the brake mechanism when ascending. FIG. 19 is a front view showing the releasing operation of the brake mechanism during lowering. FIG. 20 is an enlarged fragmentary view of the speed limiter mechanism as viewed from the back side of the article support device. (A) And (b) figure is the partial crushing enlarged front view at the time of the non-operation of a centrifugal brake mechanism, and an operation | movement, respectively.

  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 and 2 conceptually show the basic structure of a load support mechanism according to the present invention. As shown in the figure, the load support mechanism 1 includes a fixed portion 2, an article support portion 3, a spring 4 made of, for example, a tension coil spring, a spring force transmission member 5, first and second movable cams 6, 6. 7, a fixed cam 8 attached to the fixed portion 2, and a cam follower 9.

  The article support portion 3 can move up and down in the vertical direction with the article A placed on the upper end thereof. The spring 4 has an upper end fixed to the fixing portion 2 and a spring force transmission member 5 attached to the lower end, and expands and contracts in the vertical direction to generate a vertical upward biasing force. The load support mechanism 1 includes a first side support portion 10 that supports the article support portion 3 from the horizontal direction and restricts displacement in the horizontal direction when the article support portion 3 moves up and down, and a spring 4 in the vertical direction. A second side support portion 11 that further supports the spring force transmission member 5 that moves up and down in the vertical direction along with the horizontal direction and restricts the displacement in the horizontal direction when it expands and contracts.

  The first movable cam 6 is provided at the lower end of the article support portion 3 so as to be integrally movable, and has a downward first movable cam surface 12 inclined with respect to the movement direction of the article support portion. The second movable cam 7 is provided so as to be movable integrally with the spring force transmission member 5, and has an upward second movable cam surface 13 that is inclined with respect to the moving direction of the article support portion 3. The downward-facing first movable cam surface 12 and the upward-facing second movable cam surface 13 are disposed so as to face each other with the cam follower 9 interposed therebetween with the inclination directions opposite to each other.

  The fixed cam 8 has a lateral cam surface 14 that faces the first movable cam surface 12 and the second movable cam surface 13, that is, fixed to the right in FIG. 1. The lateral cam surface 14 protrudes toward the first movable cam surface and the second movable cam surface, that is, to the right in the drawing so that the inclination in the tangential direction changes over the entire length or partially from the upper end to the lower end. Is curved.

  The cam follower 9 has a straight rod shape with a circular cross section, and abuts against each cam surface horizontally between the first movable cam surface 12, the second movable cam surface 13, and the lateral cam surface 22 and at the outer peripheral surface thereof. Are arranged as follows. The first movable cam surface 12 presses the cam follower 9 to transmit the load of the article A to the spring 4 side, and the second movable cam surface 13 presses the cam follower to transmit the urging force of the spring 4 to the article support portion 3 side. To do.

  According to the present invention, the spring 4 is arranged on one side with respect to the moving direction of the article support 3, ie the vertical direction. In this embodiment, as shown in FIGS. 1 and 2, the spring 4 is arranged in parallel with the article support portion on the left and right with respect to the moving direction of the article support portion 3 and the axial direction of the cam follower 9. By arranging in this way, the depth dimension of the device can be designed to be smaller when the load support mechanism 1 is realized in an actual device. This is advantageous when the load to be supported becomes large and a large biasing force is required, and the spring 4 is enlarged.

  The “arrangement on one side” here is not limited to the narrow meaning in which the spring 4 and the article support 3 are arranged in parallel on the left and right as shown in FIG. For example, when the spring 4 shown in FIG. 1 is arranged on the extension line in the expansion / contraction direction of the spring 4 in FIG. 1, it should be broadly interpreted as including all sides such as the front and rear sides of the article support portion 3 and the extension line. Is.

  In another embodiment, the spring 4 can be a compression spring instead of a tension spring. In that case, the compression spring is disposed on the opposite side up and down across the spring force transmission member 5 in FIG. 1, the lower end thereof is fixed, and the spring force transmission member 5 is attached to the upper end. In another embodiment, in addition to the spring 4 of FIG. 1, another compression coil spring can be added on the opposite side up and down across the spring force transmission member 5. In this case, the additional coil spring has the lower end fixed and the spring force transmission member 5 is attached to the upper end. In either case, the depth dimension can be designed to be smaller when the device is actually implemented.

  Further, in the present embodiment, as shown in FIG. 2, the first movable cam 6, the second movable cam 7 and the fixed cam 8 form a symmetrical pair by two along the axial direction of the cam follower 9, respectively. Is provided. With such an arrangement, the pressing force acting on the cam follower 9 from each of the cams is distributed along the axial direction of the cam follower and becomes symmetrical. This is advantageous because the cam follower 9 is easily held horizontally between the first movable cam surface 12, the second movable cam surface 13, and the lateral cam surface 14.

  Further, since the pressing force from each cam acts on the cam follower 9 at the respective contact positions, if it is too long in the axial direction, there is a risk of excessive bending or deformation or breakage. In the present embodiment, since there are no other components between the first movable cam 6, the second movable cam 7 and the fixed cam 8 that are paired on the left and right, the axial length of the cam follower 9 is shortened. Can be advantageous.

  Further, the lateral cam surface 14 is divided into the following three regions depending on the position where the cam surface follows the cam follower 9. The first region S1 is a region in which the normal direction at the contact point with the cam follower 9 is upward with respect to the horizontal direction. The second region S2 is a region where the normal direction at the contact point with the cam follower is substantially horizontal. In other words, in the second region S2, the tangential direction at the contact point with the cam follower is substantially vertical. Here, “substantially” is slightly upward or downward from the complete horizontal direction, but the degree thereof is so small as to be negligible in terms of the operational effects of the present invention or the operation or function of the present embodiment. This includes the cases that can be considered. The third region S3 is a region in which the normal direction at the contact point with the cam follower 9 is downward with respect to the horizontal direction.

  In FIG. 1, the article support 3 on which the article A is placed is stationary at an upper position where the cam follower 9 is in the first region S <b> 1 of the lateral cam surface 14. FIG. 3 shows the cam follower 9, the first movable cam 6 (article support portion 3), the second movable cam 7 (spring force transmission member 5), the fixed cam 8, the first and second side support portions 10 in this stationary position. , 11 schematically shows the equilibrium state of the force acting on the system. In FIG. 3, in order to simplify the drawing, the first and second side support portions 10 and 11 are shown as one component.

  In order to simplify the description, the load between the article support 3 and the spring force transmission member 5 and the friction between the first and second side support parts 10 and 11 and the article support and the spring force transmission member 5 are described. Power is 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. If the resultant force in addition to the force acting on the system is smaller than the frictional force generated between the movable column, the fixed column and the spring force transmission member, the equilibrium state is maintained.

  Here, the spring force Fs of the spring 4 consisting of a tension coil spring having a spring constant k is the axial displacement x of the tension coil spring (displacement from the free length of the spring, that is, the length of the unloaded state: here, compression Fs = k · x. In order to support the article A in a stationary state at the upper limit position of the article support portion 3, the tension coil spring is held in a state of being previously extended from the free length by a predetermined initial displacement amount x0, and has already been directed upward in the vertical direction. The initial spring force (Fs0 = k · x0) is exhibited.

  In FIG. 3, at the contact point Pa between the cam follower 9 and the first movable cam surface 12, the load W of the article A, the reaction force Ra acting from the cam follower 9 in the normal direction of the first movable cam surface 12, and the first side The horizontal reaction force Rd1 acting on the article support portion 3 from the side support portion 10 is balanced. The magnitude of the vertical direction component Ra1 of the reaction force Ra is equal to the load W, and the magnitude of the horizontal direction component Ra2 is equal to the reaction force Rd1 from the first side support portion 10. The force Fa that the first movable cam surface 12 presses the cam follower 9 is a resultant force of the load W and the reaction force Rd1.

  At the contact Pb between the cam follower 9 and the second movable cam surface 13, the spring force Fs of the spring 4, the reaction force Rb acting in the normal direction from the cam follower 9 to the second movable cam surface 13, and the second side support portion 11, 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 from the second side support portion 11. The force Fb that the second movable cam surface 13 presses the cam follower 9 is a resultant force of the spring force Fs and the reaction force Rd2.

  At the contact point Pc between the cam follower 9 and the lateral cam surface 14, the forces Fa and Fb acting on the cam follower from the first movable cam surface 12 and the second movable cam surface 13 and the reaction acting on the cam follower in the normal direction from the lateral cam surface 14. The force Rc is balanced. Since the cam follower 9 is in the first region S1 of the lateral cam surface 14, 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 article support part 3 and the spring force transmission member 5 receive from the first and second side support parts 10 and 11, respectively. is there.

When the cam follower 9 is stationary at a certain position on the lateral cam surface 14, 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, frictional force is generated between the members as described above, and even if the resultant force represented by this relational expression is not 0 and has a slight value, the resultant force is not reduced between the members. If it is smaller than the frictional force, the equilibrium state is maintained.

  In the case of FIG. 3, the magnitude of the spring force Fs of the spring 4 is smaller than the load W. Accordingly, the vertical force component Rc1 of the reaction force Rc acting upward from the lateral cam surface 14 is added to the spring force Fs as an assist force, thereby realizing the balance with the load W in the vertical direction. When the article support part 3 is pushed down or pushed up in this state, the force is added to the load W or the spring force Fs, and the balance is lost. Therefore, the article A can be easily raised and lowered with a relatively small force.

  When the article support unit 3 is raised and lowered, the cam follower 9 moves downward or upward while being displaced in the left-right direction along the lateral cam surface, the first movable cam surface, and the second movable cam surface. While the cam follower 9 is within the first region S1 of the lateral cam surface 14, the upward vertical component Rc1 of the reaction force Rc assists the spring force Fs to balance the load W.

  Within the range of the first region S1, the spring force Fs of the spring 4 is such that the spring force transmission member 5 pressed against the cam follower 9 by the lowering of the article support portion 3 moves downward, and the displacement of the tension coil spring increases. Correspondingly increases. As the spring force Fs increases, the assist force due to the vertical component Rc1 of the reaction force Rc can be reduced. The inclination of the lateral cam surface 14 with respect to the vertical direction of the tangential direction also decreases as it approaches the second region S2 downward.

  The greater the force with which the cam follower 9 presses the lateral cam surface 14 in the horizontal direction due to the pressing force from the first movable cam surface 12 and the second movable cam surface 13, the greater the horizontal component Rc2 of the reaction force Rc. The force Rc and its vertical component Rc1 are increased. The reaction force Rd1 and the reaction force Rd2 increase when the inclination of the first movable cam surface and the second movable cam surface with respect to the vertical direction is reduced, and decrease when the inclination is increased. By adjusting the inclination of the first movable cam surface 12 and the second movable cam surface 13 with respect to the vertical direction, a pressing force with an appropriate magnitude on the lateral cam surface 14 can be obtained.

  In other words, the reaction force Rc of the lateral cam surface 14 reduces the inclination of the lateral cam surface with respect to the vertical direction when the horizontal pressing force against the lateral cam surface is large, and the vertical component of the same magnitude. An upward assist force in the vertical direction to Rc1, that is, the spring force Fs can be obtained. The lateral cam surface 14 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. Thereby, the width dimension of the whole fixed cam 8 can be made small.

  Conversely, if the inclination of the first movable cam surface 12 and / or the second movable cam surface 13 with respect to the vertical direction is increased or one of the first movable cam surface 12 or the second movable cam surface 13 is omitted, the lateral cam surface Accordingly, the pressing force in the horizontal direction with respect to 14 decreases, and the reaction force Rc from the lateral cam surface 14 decreases accordingly. Here, in order to obtain the upward vertical direction component Rc1 of the same size, the inclination of the lateral cam surface 14 with respect to the vertical direction must be increased, and the laterally convex shape with a tighter curve, that is, a larger curvature. This increases the width of the entire fixed cam 8.

  4 shows an intermediate position in which the article support portion 3 on which the article A is placed is pushed down from the upper position in FIG. 1 so that the cam follower 9 is in the second region S2 of the lateral cam surface 14 as indicated by an imaginary line in FIG. FIG. 2 schematically shows an equilibrium state of forces acting on the system including the cam follower 9, the first movable cam 6, the second movable cam 7, the fixed cam 8, and the first and second side support portions 10 and 11. Is shown. Similarly, the load of the support member 3 and the spring force transmission member 5 and the frictional force between the article support portion 3 and the spring force transmission member and the first and second side support portions 10 and 11 are omitted for simplification. To explain.

  As in the case of FIG. 3, at the contact point Pa between the cam follower 9 and the first movable cam surface 12, the load W of the article A and the reaction force Ra acting in the normal direction from the cam follower 9 to the first movable cam surface 12. The horizontal reaction force Rd1 acting on the article support 3 from the first side support 10 is balanced. The magnitude of the vertical direction component Ra1 of the reaction force Ra is equal to the load W, and the magnitude of the horizontal direction component Ra2 is equal to the reaction force Rd1 from the first side support portions 10 and 11. The force Fa that the first movable cam surface 12 presses the cam follower 9 is a resultant force of the load W and the reaction force Rd1.

  At the contact Pb between the cam follower 9 and the second movable cam surface 13, the spring force Fs of the spring 4, the reaction force Rb acting in the normal direction from the cam follower 9 to the second movable cam surface 13, and the second side support portion The horizontal reaction force Rd2 acting on the spring force transmission member 5 from 11 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 from the second side support portion 11. The force Fb that the second movable cam surface 13 presses the cam follower 9 is a resultant force of the spring force Fs and the reaction force Rd2.

  At the contact point Pc between the cam follower 9 and the lateral cam surface 14, the forces Fa and Fb acting on the cam follower from the first movable cam surface 12 and the second movable cam surface 13 and the reaction acting on the cam follower in the normal direction from the lateral cam surface 14. The force Rc is balanced. Since the cam follower 9 is in the second region S2 of the lateral cam surface 14, the reaction force Rc is substantially only a horizontal component and has no vertical component. Therefore, the magnitude of the reaction force Rc is the sum of the reaction force Rd1 and the reaction force Rd2 acting on the article support part 3 and the spring force transmission member 5 from the first and second side support parts 10 and 11.

  Thus, when the cam follower 9 is located in the second region S2 of the lateral cam surface 14, the spring force Fs and the load W of the spring 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 14. Even in this state, when the article support portion 3 is pushed down or pushed up, the force is added to the load W or the spring force Fs, and the balance is lost. Therefore, the article A can be easily raised and lowered with a relatively small force.

  FIG. 5 shows a case where the article support portion 3 on which the article A is placed is further pushed down so that the cam follower 9 stops at a lower position in the third region S3 of the lateral cam surface 14 as indicated by an imaginary line in FIG. FIG. 2 schematically shows a balance state of forces acting on the system including the cam follower 9, the first movable cam 6, the second movable cam 7, the fixed cam 8, and the first and second side support portions 10 and 11. . Similarly, the load of the support member 3 and the spring force transmission member 5 and the frictional force between the article support portion 3 and the spring force transmission member and the first and second side support portions 10 and 11 are omitted for simplification. To explain.

  In the figure, at the contact point Pa between the cam follower 9 and the first movable cam surface 12, the load W of the article A, the reaction force Ra acting in the normal direction from the cam follower 9 to the first movable cam surface 12, and the first side. The reaction force Rd1 acting in the horizontal direction from the side support portion 10 to the article support portion 3 is balanced. The magnitude of the vertical direction component Ra1 of the reaction force Ra is equal to the load W, and the magnitude of the horizontal direction component Ra2 is equal to the reaction force Rd1 from the first side support portion 10. The force Fa that the first movable cam surface 12 presses the cam follower 9 is a resultant force of the load W and the reaction force Rd1.

  At the contact Pb between the cam follower 9 and the second movable cam surface 13, the spring force Fs of the spring 4, the reaction force Rb acting in the normal direction from the cam follower 9 to the second movable cam surface 13, and the second side support portion 11, 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 from the second side support portion 11. The force Fb that the second movable cam surface 13 presses the cam follower 9 is a resultant force of the spring force Fs and the reaction force Rd2.

  At the contact point Pc between the cam follower 9 and the lateral cam surface 14, the forces Fa and Fb acting on the cam follower from the first movable cam surface 12 and the second movable cam surface 13 and the reaction acting on the cam follower in the normal direction from the lateral cam surface 14. The force Rc is balanced. Since the cam follower 9 is in the third region S3 of the lateral cam surface 14, 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 article support part 3 and the spring force transmission member 5 receive from the first and second side support parts 10 and 11, respectively. is there.

  In the lower position, the magnitude of the spring force Fs of the spring 4 is larger than the load W. Therefore, the vertical component Rc1 of the reaction force Rc acting downward from the lateral cam surface 14 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, when the article support portion 3 is pushed down or pushed up, the force is added to the load W or the spring force Fs, and the balance is lost. Therefore, the article A can be easily raised with a relatively small force. When the article support unit 3 is moved up and down, the cam follower 9 moves downward or upward while being displaced in the left-right direction along the lateral cam surface, the first movable cam surface, and the second movable cam surface. While the cam follower 9 is within the range of the third region S3 of the lateral cam surface 14, the downward vertical component Rc1 of the reaction force Rc acts in a direction to balance the load W by reducing the push-up force due to the spring force Fs. .

  Within the range of the third region S3, the spring force Fs of the spring 4 is moved upward against the cam follower 9 by the ascent of the article support portion 3, and the displacement of the tension coil spring is reduced. Decrease correspondingly. Along with this, the vertical component Rc1 of the reaction force Rc that reduces the push-up force by the spring force Fs can be reduced. Accordingly, the inclination of the lateral cam surface 14 with respect to the vertical direction of the tangential direction also decreases as it approaches the second region S2 upward.

  Also in the third region S3, the horizontal component of the reaction force Rc increases as the force that the cam follower 9 presses the lateral cam surface 14 in the horizontal direction by the pressing force from the first movable cam surface 12 and the second movable cam surface 13 increases. Rc2 increases, and accordingly, the reaction force Rc and its vertical component Rc1 increase. The reaction force Rd1 and the reaction force Rd2 increase when the inclination of the first movable cam surface 12 and the second movable cam surface 13 with respect to the vertical direction is reduced, and decrease when the inclination is increased. By adjusting the inclination of the first movable cam surface 12 and the second movable cam surface 13 with respect to the vertical direction, a pressing force with an appropriate magnitude on the lateral cam surface 14 can be obtained.

  In other words, the reaction force Rc of the lateral cam surface 14 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 14 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, if the inclination of the first movable cam surface 12 and / or the second movable cam surface 13 with respect to the vertical direction is increased or one of the first movable cam surface 12 or the second movable cam surface 13 is omitted, the lateral cam surface Accordingly, the pressing force in the horizontal direction with respect to 14 decreases, and the reaction force Rc from the lateral cam surface 14 decreases accordingly. Here, in order to obtain the downward vertical direction component Rc1 of the same size, the inclination of the lateral cam surface 14 with respect to the vertical direction must be increased, and the laterally convex shape having a tighter curve, that is, a larger curvature. This increases the width of the entire fixed cam 8.

  The lateral cam surface 14 as a whole is given a force for pressing the lateral cam surface 14 in the horizontal direction via the cam follower 9 from the first movable cam surface 12 and the second movable cam surface 13 inclined with respect to the vertical direction. In addition, by appropriately setting the size, a necessary and sufficient vertical component Rc1 can be secured, and the first to third regions S1 to S3 have a laterally convex shape having a gentle or small curvature. can do. As a result, the width of the entire fixed cam 8 can be made relatively small, and the size can be reduced when the device is actually made.

  As described above, according to the present embodiment, the cam follower 9, the first movable cam 6, the second movable cam 7, the fixed cam 8, and the first and second side support portions 10 and 11 are formed in the entire region of the lateral cam surface 14. The load W of the article A, the spring force Fs of the spring 4, the reaction force from the fixed cam 8, and the reaction force from the first and second side support portions 10, 11 are applied around the cam follower 9. Equilibrium. As a result, the article supporting portion 3 on which the article A is placed can be kept stationary at a desired height position within the range of the vertical stroke, and the position can be held up and down easily with relatively little force.

  The basic configuration of the present invention described above can be implemented with various modifications and changes. For example, an additional spring can be arranged in parallel on the opposite side of the spring 4 in FIG. 1 across the article support portion 3, the upper end thereof can be fixed, and the lower end can be attached with the spring force transmission member 5. As a result, the article support 3 on which the article A is placed can be supported in a balanced manner on the left and right and can be moved up and down.

  Further, another set of the first movable cam, the second movable cam, the fixed cam and the cam follower which are the same as the first movable cam 6, the second movable cam 7, the fixed cam 8 and the cam follower 9 in FIG. They can be arranged mirror-symmetrically. At this time, it is preferable that the additional first movable cam and the second movable cam are provided on the common article support portion 3 and the spring force transmission member 5, respectively. Thus, by constituting symmetrically, the load and spring force which each said cam bears can be decreased, and a bigger load can be supported stably as a whole.

  A preferred embodiment of the article support apparatus to which the modification of the present invention is specifically applied is shown in FIGS. The article support device 20 of the present embodiment is for supporting a relatively heavy article B such as a television monitor, and a stand 21 installed on the floor surface and a fixed frame portion fixed to the base. 22, a support frame portion 23 attached to the fixed portion so as to be movable up and down, and left and right spring portions 24 and 25. The article B is integrally and detachably attached to the support frame portion 23.

  The stand 21 includes a pair of left and right vertical Y-shaped legs 21a arranged in parallel with a predetermined interval, and a plurality of horizontal reeds 21b laid across both the legs 21a. The fixed frame portion 22 is detachably fixed to the horizontal bar 21b of the stand 21 in a suspended manner by, for example, an appropriate fastener.

  The fixed frame portion 22 has a substantially rectangular frame structure, and includes upper and lower frames 26 and 27 extending horizontally, and left and right side frames 28 and 29 extending vertically between the upper frame and the lower frame. Furthermore, the fixed frame portion 22 is provided with a first brake rail 30 at its center extending vertically between the upper frame and the lower frame. Each of the side frames 28 and 29 is formed with a U-shaped slide rail 31 that opens to the inner side of the frame structure from the upper end to the lower end of the side frame. The penetrating guide grooves 32 and 33 are formed from the vicinity of the center to the lower end.

  The support frame portion 23 has a generally rectangular frame structure, and includes left and right guide frames 34 and 35 extending vertically, an upper frame 36 extending horizontally between the two guide frames, and two lower portions spaced slightly above and below. In order to fix the article B on the front side of the frames 37a and 37b, each frame has a pair of left and right mounting stays 38 extending vertically inside the guide frame. Further, the support frame portion 23 includes a brake device 39 provided at the upper center thereof, and an operation handle 40 for releasing the brake device and raising and lowering the support frame portion. The operation handle 40 is attached so that the brake device 39 can be operated via left and right vertical transmission rods 41 coupled to both ends thereof.

  The support frame portion 23 is fitted to the fixed frame portion 22 so that the left and right guide frames 34 and 35 are slidably fitted in the slide rails 31 of the corresponding left and right side frames 28 and 29 of the fixed frame portion, respectively. And mounted so as to be movable up and down along the slide rail. The left and right guide frames 34 and 35 are slidably contacted with the inner surface of the slide rail 31 in order to reduce or eliminate friction and other resistance that may occur with the inner surface when sliding in the slide rail 31. A plurality of moving rollers 42 are attached. As a result, the support frame portion 23 can smoothly move in the vertical direction without rattling or displacing from the left and right with respect to the fixed frame portion 22.

  The left and right spring portions 24 and 25 are arranged in parallel with the support frame portion in the movement direction of the support frame portion 23, that is, in the vertical direction, just outside the left and right sides of the fixed frame portion 22. Each spring part 24 and 25 has two tension coil springs 43 and 44 arranged in parallel, respectively. The tension coil springs 43, 44 are suspended vertically by fixing the upper ends thereof to the upper frame 26 of the fixed frame portion 22, and the lower ends thereof are coupled to the left and right end portions 45 a, 45 b of the common spring force transmission member 45. .

  A first movable cam member 46 is integrally attached to the lower frame 37 b below the support frame portion 23. The first movable cam member 46 has two generally inverted isosceles triangular first cam plates 46a and 46b arranged in parallel in the front-rear direction in the drawing. The first cam plates 46a and 46b have a pair of downward first movable cam surfaces 47 and 48, which are end surfaces of the left and right lower sides of the inverted isosceles triangle, respectively. The first movable cam surfaces 47 and 48 are provided symmetrically opposite to each other with respect to the moving direction of the support frame portion 23, that is, the vertical direction, with the same inclination.

  A second movable cam member 49 is formed integrally with the spring force transmission member 45. The second movable cam member 49 includes two substantially isosceles triangular second cam plates 49a and 49b arranged in parallel in the front-rear direction in the drawing. The second cam plates 49a and 49b have a pair of upward second movable cam surfaces 50 and 51 formed by end faces of the left and right sides of the isosceles triangle. The second movable cam surfaces 50 and 51 are provided in a bilaterally symmetric manner by being inclined with the same inclination in opposite directions with respect to the moving direction of the support frame portion 23, that is, the vertical direction.

  In the spring force transmission member 45, the second cam plates 49a and 49b are arranged inside the frame structure of the fixed frame portion 22, and the left and right end portions 45a and 45b are guide grooves 32 and 33 of the left and right side frames 28 and 29, respectively. And is slidable up and down along the guide groove. The upper limit position of the spring force transmission member 45 is defined by the upper ends of the guide grooves 32 and 33. When the article B is supported, the tension coil springs 43 and 44 are expanded in advance by a predetermined amount of displacement from the free length so that the spring force transmission member 45 can be stationary at the upper limit position, and a predetermined amount upward in the vertical direction. The initial spring force is set.

  Fixed cam members 52 and 53 are attached to the fixed frame portion 22 symmetrically inside the frame structure. The fixed cam members 52, 53 are each composed of two third cam plates 52a, 52b, 53a, 53b which are arranged in parallel in the front-rear direction in the figure and whose upper ends are on the first brake rail 30. Are supported by pivot pins 54a and 54b so as to be swingable left and right. The lower end of the third cam plate is fixed by screwing to stays 55 and 56 protruding from the lower frame 27 of the fixed frame portion 22. The stays 55 and 56 are provided so as to be movable within a certain range in the left-right direction with respect to the lower frame 27, and the position of the third cam plate is adjusted around the pivot pin by changing its position. can do.

  The first movable cam member 46 and the second movable cam member 49 are arranged such that the corresponding left and right first movable cam surfaces 47 and 48 and the second movable cam surfaces 50 and 51 face each other and incline in opposite directions. Has been placed. The fixed cam members 52 and 53 have inwardly extending cam surfaces 57 and 58 formed of end faces facing inwardly extending in the vertical direction, that is, facing the corresponding first movable cam surface and second movable cam surface.

  The lateral cam surfaces 57 and 58 face the corresponding first movable cam surface and the second movable cam surface so that the inclination in the tangential direction changes substantially over the entire length from the upper end to the lower end or partially. Curved in a convex shape. The inclination of the entire lateral cam surfaces 57 and 58 can be easily adjusted by changing the positions of the stays 55 and 56 in the lower frame 27 and rotating the third cam plate.

  As shown in FIGS. 8 and 9, the left and right corresponding first movable cam surfaces 47, the second movable cam surfaces 50, and the lateral cam surfaces 57, and the first movable cam surfaces 48 and the second movable cam surfaces 51, respectively. The cam follower members 59 and 60 are disposed between the cam surface 58 and the lateral cam surface 58 so as to contact the cam surfaces. The cam follower members 59 and 60 are made of, for example, a straight circular rod made of metal, and six rolling bearings are fitted on the outer periphery thereof along the axial direction. As shown in FIG. 9, the respective rolling bearings 61a, 61b, 62a, 62b, 63a, 63b are arranged so as to individually contact the respective cam surfaces.

  In FIG. 9, the first cam plates 46 a and 46 b, the second cam plates 49 a and 49 b, and the third cam plates 52 a and 52 b are arranged so as to be symmetrical two by two along the axial direction of the cam follower member 59. Therefore, the force with which each cam plate presses the cam follower member 59 is distributed along the axial direction and acts symmetrically. Thus, the cam follower member 59 is easily and stably held horizontally between the first movable cam surface 47, the second movable cam surface 50, and the lateral cam surface 57.

  Further, the cam follower member 59 does not have another component between the first cam plates 46a and 46b, the second cam plates 49a and 49b, and the third cam plates 52a and 52b that are paired with each other, and is spaced apart in the axial direction. Can be arranged short. As a result, the axial length of the cam follower member 59 can be shortened, and the possibility of excessive bending, deformation, or breakage that can occur when the cam follower member 59 is too long can be eliminated.

  Similarly, the laterally facing cam surfaces 57 and 58 are divided into three regions depending on the contact positions with the cam follower members 59 and 60. The first region S1 is a region in which the normal direction at the contact point with the cam follower member 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, that is, the tangential direction is substantially vertical. As described above, the term “substantially” is slightly upward or downward from the complete horizontal direction, but the degree thereof is negligibly small in terms of the operational effect of the article support device 20 or its operation or function. This includes the cases that can be considered. The third region S3 is a region in which the normal direction at the contact point with the cam follower member is downward with respect to the horizontal direction.

  FIG. 8 shows a case where the support frame portion 23 on which the article B is placed is at the uppermost position. The cam follower members 59 and 60 are stationary at the upper ends of the first regions S1 of the lateral cam surfaces 57 and 58. At this position, the load W of the article B acting on the system composed of the cam follower member, the fixed frame portion 22, the support frame portion, the spring force transmission member 45, and the fixed cam members 52, 53, and the spring force of the spring members 24, 25 Fs, the reaction force from the fixed frame portion, and the reaction force from the fixed cam member are balanced around the cam follower member.

  In the first region S1, the displacement of each of the tension coil springs 43 and 44 is small, and the spring force Fs is smaller than the load W of the article B. Since the reaction force Rc acting on the cam follower member 59 from the lateral cam surfaces 57 and 58 includes an upward vertical component, it is balanced with the load W in the vertical direction by adding this to the spring force Fs as an assist force. .

  FIG. 10 shows a case where the support frame portion 23 on which the article B is placed is in an intermediate position. The cam follower members 59 and 60 are stationary at positions in the second region S2 of the lateral cam surfaces 57 and 58. Even at this intermediate position, from the cam follower member, the fixed frame portion, the support frame portion, the spring force transmission member and the fixed cam member, the load W of the article B acting on the system, the spring force Fs of the spring member, and the fixed frame portion. The reaction force and the reaction force from the fixed cam member are balanced around the cam follower member.

  In the second region S2, the reaction force Rc from the lateral cam surfaces 57, 58 is substantially only a horizontal component and has no vertical component. In the vertical direction, the spring force Fs of the spring members 24 and 25 and the load W are substantially balanced.

  FIG. 11 shows a case where the support frame portion 23 on which the article B is placed is at the lowest position. The cam follower members 59 and 60 are stationary at the lower end of the third region S3 of the lateral cam surfaces 57 and 58. Even at this lower end position, from the cam follower member, the fixed frame portion, the support frame portion, the spring force transmitting member and the fixed cam member, the load W of the article B acting on the system, the spring force Fs of the spring member, and the fixed frame portion. The reaction force and the reaction force from the fixed cam member are balanced around the cam follower member.

  In the third region S3, the displacement of each of the tension coil springs 43 and 44 is large, and the spring force Fs is larger than the load W of the article B. The reaction force Rc acting on the cam follower members 59, 60 from the lateral cam surfaces 57, 58 includes a downward vertical component, which acts in a direction to reduce the push-up force due to the spring force Fs, thereby causing a load in the vertical direction. Equilibrium with W.

  When the load W of the article B is decreased, the spring members 24 and 25 are not changed, so that the spring force Fs is relatively increased. Accordingly, the lateral cam surfaces 57 and 58 shift the first region S1 to the third region S3 upward as a whole, and in the first region S1, the assist force to the spring force Fs by the lateral cam surface is reduced. In the third region S3, it is necessary to increase the downward force for reducing the push-up force due to the spring force Fs.

  On the other hand, when the load W of the article B increases, the spring members 24 and 25 are not changed, so that the spring force Fs becomes relatively small. Accordingly, the lateral cam surfaces 57 and 58 shift the first region S1 to the third region S3 downward as a whole, and in the first region S1, the assist force to the spring force Fs by the lateral cam surface is increased. In the third region S3, it is necessary to reduce the downward force for reducing the push-up force by the spring force Fs.

  In the article support device 20, as described above, the positions of the stays 55 and 56 in the lower frame 27 are changed, and the third cam plates 52a, 52b, 53a, and 53b are rotated around the pivot pins 54a and 54b. The position is fixed at the position, and the inclination of the entire lateral cam surfaces 57 and 58 is adjusted. When the load B is small, the stay may be moved in such a direction that the lower ends of the left and right third cam plates approach each other. Conversely, when the load B is large, the stay is moved in a direction in which the lower ends of the left and right third cam plates are separated from each other.

  In the article support apparatus 20, since the force is balanced in the vertical direction at the stationary position, the article B can be easily moved to another height position with a relatively small force from any height position. Can do. On the other hand, as the mass of the article increases, the inertial force acting on the article being moved increases accordingly, and it may be difficult to stop at a desired position. In the worst case, the support frame part 23 on which the article B is placed violently collides with the fixed frame part 22 at the upper end or the lower end of the vertical stroke.

  As means for solving such a problem, generally, an elastic body such as a damper, a shock absorber, or rubber that attenuates or absorbs kinetic energy is known. For example, if a gas spring or oil damper using fluid resistance is used, the entire apparatus becomes complicated, large and heavy, not only difficult to handle, but also expensive. An elastic body such as rubber cannot always obtain a sufficient effect.

  The article support device 20 according to the present embodiment is a buffer having an effective and simple configuration for decelerating the movement of the support frame 23 at the upper and lower ends of the vertical stroke of the support frame 23 and stopping it without causing a large impact. It has a mechanism. As will be described below, this buffer mechanism is effectively realized by adding a new and innovative device to the cam plate that drives the cam follower member 59 based on the basic technical concept of the present invention. .

  FIG. 12 is an enlarged view of the vicinity of the upper end of the lateral cam surface 57 of the third cam plate 52a on the left side in the drawing. In this figure, the contact area between the cam follower member 59 and the lateral cam surface 57 indicated by the solid line has an effective area of the lateral cam surface in which the function of causing the support frame portion 23 to which the article B is attached to stand still at a desired height position is exhibited. This is the upper limit position C1 of S. On the lateral cam surface 57, an upper buffer area L1 and an upper stopper area M1 are continuously provided extending further upward from the upper limit position C1.

  The upper buffer area L1 is greatly curved in the opposite direction to the virtual lateral cam surface extension 57 'indicated by the imaginary line in the figure, and passes through a point D1 whose tangential direction is in the vertical direction, and further, the upper stopper area M1 Is curving towards. The upper stopper region M1 is a downward horizontal surface that completely prevents the cam follower member 59 from moving upward.

  In the upper buffer area L1, the inclination in the tangential direction with respect to the vertical direction decreases rapidly from the upper limit position C1 to the point D1, and accordingly, the pressing force or reaction force from the lateral cam surface 57 to the cam follower member 59 is upward. The vertical component decreases rapidly and becomes zero at point D1. Thereby, the assist force to the urging force of the spring portions 24 and 25 is lost rapidly, and the ascent of the article B and the support frame portion 23 is greatly decelerated.

  Conversely, in the range from the point D1 to the upper stopper region M1, the reaction force from the lateral cam surface 57 to the cam follower member 59 generates a downward vertical component. Thereby, since the force which pushes down the cam follower member 59 acts, the raise of the article | item B and the support frame part 23 is further decelerated further.

  Thus, by the downward deceleration action, the guide frames 34 and 35 of the support frame portion 23 collide with the upper end of the slide rail 31 of the fixed frame portion 22, and the end portions 45 a and 45 b of the spring force transmission member 45 are Without colliding with the upper ends of the guide grooves 32 and 33 of the fixed frame portion, the cam follower member 59 stops at the same time as the support frame portion in the upper buffer region L1 or does not stop at a relatively low speed. Stops after entering the stopper zone M1. In this stop position, since the weight of the article B and the support frame part 23 exceeds the push-up force of the spring parts 24 and 25, the article B and the support frame part 23 are slightly lowered by their own weight after being stopped for a very short time. The cam follower member 59 returns to the vicinity of the upper limit position C1 and stops.

  FIG. 13 is an enlarged view of the vicinity of the lower end of the lateral cam surface 57 of the third cam plate 52a. In the drawing, the contact point between the cam follower member 59 and the lateral cam surface 57 indicated by a solid line is the lower limit position C2 of the effective region S of the lateral cam surface. The lateral cam surface 57 is provided with a lower buffer area L2 extending further downward from the lower limit position C2.

  In the lower buffer area L2, the upper buffer area L1 is greatly curved in the opposite direction to the virtual lateral cam surface extension portion 57 "shown by an imaginary line in the drawing, and passes through a point D2 in which the tangential direction is in the vertical direction. From the lower limit position C2 to D2, the inclination in the tangential direction with respect to the vertical direction suddenly decreases, and accordingly, the reaction force from the lateral cam surface 57 to the cam follower member 59 is a downward vertical component. Decreases suddenly and becomes 0 at point D2. Thereby, the force to push down the support frame portion 23 against the urging force of the spring portions 24, 25 is suddenly lost, and the article B and the support frame portion are lost. The descent of is greatly decelerated.

  In the range beyond point D2, conversely, the reaction force from the lateral cam surface 57 to the cam follower member 59 generates an upward vertical component. Thereby, since the force which pushes up the cam follower member 59 acts, the fall of the article | item B and the support frame part 23 is further decelerated further.

  Thus, the upward deceleration action causes the guide frames 34 and 35 of the support frame portion 23 to collide with the lower end of the slide rail 31 of the fixed frame portion 22, and the end portions 45 a and 45 b of the spring force transmission member 45 are The cam follower member 59 stops in the lower buffer region L2 simultaneously with the support frame portion without colliding with the lower ends of the guide grooves 32 and 33 of the fixed frame portion. At this stop position, the article B and the support frame portion 23 have their weight exceeding the push-up force of the spring portions 24 and 25, so after stopping for a very short time, the article B and the support frame portion 23 are slightly lifted by the biasing force of the spring portion. Ascending, the cam follower member 59 returns to the vicinity of the lower limit position C2 of the lateral cam surface 57 and stops.

  12 and 13, only the third cam plate 52a on the left side in the figure has been described, but the upper buffer region L1, the upper stopper region M1, and the lower buffer region L2 are similarly provided on the right third cam plate 52b. be able to. Of course, it may be provided only on one of the third cam plates. Further, only one of the upper buffer area L1 and the upper stopper area M1 or the lower buffer area L2 can be provided.

  FIG. 14 is a modification of FIG. 13 and shows the vicinity of the lower end of the lateral cam surface 57 of the third cam plate 52a in an enlarged manner as in FIG. In the figure, the cam follower member 59 and the lateral cam surface 57 indicated by a solid line are in contact with each other at the lower limit position C2 corresponding to the lowest position of the support frame portion 23 in the effective area S of the lateral cam surface. The lateral cam surface 57 is provided with an extension region E formed so that its inclination can exhibit the same function as the effective region S in a certain range below the lower limit position C2.

  The first movable cam surface 47 of the first cam plate 46a is in contact with the cam follower member 59 at the contact point G1 at the lowest position of the support frame portion 23. In this embodiment, this contact point is an upper limit position where the cam follower member 59 can move while contacting the first movable cam surface 47 when the support frame portion 23 moves between the uppermost position and the lowermost position.

  In the first movable cam surface 47, the region below the upper limit position G1 is inclined with a constant inclination with respect to the vertical direction. As described above, the inclination is such that the cam follower cooperates with the second movable cam surface 50 and the lateral cam surface 57 so that the support frame portion 23 can rest at a desired height position between the uppermost position and the lowermost position. The member 59 is set to apply a desired pressing force in the horizontal direction to the lateral cam surface 57 when the member 59 is pressed by the first movable cam surface.

  The first movable cam surface 47 is provided with a buffer area N1 extending further upward from the upper limit position G1. The buffer area N1 is curved so that its inclination becomes larger in the direction approaching the horizontal direction, that is, in the vertical direction. Therefore, even if the cam follower member 59 is pressed from the first movable cam surface 47 with the same force, the horizontal component is smaller than that in the case of the same inclination as the region below the upper limit position G1. Accordingly, the horizontal component of the pressing force from the cam follower member 59 to the lateral cam surface 57 becomes smaller than when the inclination of the first movable cam surface is the same as the region below the upper limit position G1.

  As a result, the downward vertical component of the reaction force of the lateral cam surface 57 against the cam follower member 59 decreases. As a result, the force that pushes down the support frame portion 23 against the urging force of the spring portions 24 and 25 is suddenly lost, and the lowering of the article B and the support frame portion is greatly decelerated.

  Thus, the upward decelerating action causes the cam follower member without causing a collision between the support frame portion 23 and the fixed frame portion 22 and / or between the spring force transmission member 45 and the fixed frame portion. 59 stops in the buffer area N1 simultaneously with the support frame portion. At this stop position, the article B and the support frame portion 23 are slightly lifted by the urging force of the spring portion after being momentarily stopped because the push-up force of the spring portions 24 and 25 exceeds their weight. The cam follower member 59 returns to the vicinity of the upper limit position G1 of the first movable cam surface 47 and stops.

  FIG. 15 is another modified example of FIG. 13, and similarly to FIG. 13, an enlarged view of the vicinity of the lower end of the lateral cam surface 57 of the third cam plate 52 a is shown. Similarly to FIG. 14, the cam follower member 59 and the lateral cam surface 57 indicated by a solid line are in contact with each other at the lower limit position C2 corresponding to the lowest position of the support frame portion 23 in the effective area S of the lateral cam surface. The lateral cam surface 57 is provided with an extension region E formed so that its inclination can exhibit the same function as the effective region S in a certain range below the lower limit position C2.

  The second movable cam surface 50 of the second cam plate 49a is in contact with the cam follower member 59 at the contact H1 at the lowest position of the support frame portion 23. In this embodiment, this contact point is a lower limit position at which the cam follower member 59 can move while contacting the second movable cam surface 50 when the support frame portion 23 moves between the uppermost position and the lowermost position.

  In the second movable cam surface 50, the region above the lower limit position H1 is inclined with a constant inclination with respect to the vertical direction. As described above, the inclination is such that the cam follower cooperates with the first movable cam surface 47 and the lateral cam surface 57 so that the support frame portion 23 can rest at a desired height position between the uppermost position and the lowermost position. The member 59 is set to apply a desired pressing force in the horizontal direction to the lateral cam surface 57 when the member 59 is pressed by the second movable cam surface.

  The second movable cam surface 50 is provided with a buffer area N2 extending further downward from the lower limit position H1. The buffer area N2 is curved so that its inclination approaches the horizontal direction, that is, increases in the vertical direction, and in the middle, the tangential direction passes through the point H2 that faces the horizontal direction and is further curved upward.

  Therefore, in the buffer region N2, from the lower limit position H1 to the point H2, even if the cam follower member 59 is pressed from the second movable cam surface 50 with the same magnitude of force, the horizontal component is higher than the lower limit position H1. It becomes smaller than the case of the same inclination as the area. Accordingly, the horizontal component of the pressing force from the cam follower member 59 to the lateral cam surface 57 becomes smaller than when the inclination of the second movable cam surface is the same as the region above the lower limit position H1.

  As a result, the downward vertical component of the reaction force of the lateral cam surface 57 against the cam follower member 59 decreases. As a result, the force that pushes down the support frame portion 23 against the urging force of the spring portions 24 and 25 is suddenly lost, and the lowering of the article B and the support frame portion is greatly decelerated.

  Conversely, in the range from the point H2, the pressing force from the second movable cam surface 50 to the cam follower member 59 acts upward. This pressing force has a horizontal direction component that reduces the pressing force on the cam follower member 59 and an upward vertical direction component. As a result, the force that pushes up the cam follower member 59 further increases, so that the lowering of the article B and the support frame portion 23 is further greatly decelerated.

  Thus, the upward decelerating action causes the cam follower member without causing a collision between the support frame portion 23 and the fixed frame portion 22 and / or between the spring force transmission member 45 and the fixed frame portion. 59 stops in the buffer area N2 simultaneously with the support frame portion. At this stop position, the article B and the support frame portion 23 are slightly lifted by the urging force of the spring portion after being momentarily stopped because the push-up force of the spring portions 24 and 25 exceeds their weight. The cam follower member 59 returns to the vicinity of the lower limit position H1 of the second movable cam surface 50 and stops.

  14 and 15, only the first cam plate 46a and the second cam plate 49a on the left side in the figure have been described, but the same applies to the first cam plate 46b and the second cam plate 49b on the right side. it can. In addition to the first movable cam surface 47 or the second movable cam surface 50, the buffer region can be provided at the same time on both.

  In this embodiment, in order to decelerate and / or stop the support frame portion 23 at the upper and lower ends of the vertical stroke, the lateral cam surface 57 is extended above and below the effective area S, and the force acting around the cam follower member 59 Is provided with a buffer region where becomes non-equilibrium. In another embodiment, in this way, the region where the force around the cam follower member 59 is unbalanced is between the regions where the force around the cam follower member is balanced, i.e. the range of the effective region S of the lateral cam surface 57. Can be provided inside.

  For example, in the first region S1 of the lateral cam surface 57, there is a non-equilibrium region of inclination in a direction in which the upward assist force is reduced from the equilibrium state and a non-equilibrium region of inclination in a direction to return the assist force to the original magnitude again. Can be provided between the equilibrium region and the equilibrium region. Further, in the third region S3 of the lateral cam surface 57, a non-equilibrium region having an inclination in which the downward force for reducing the biasing force of the spring is reduced from the equilibrium state and a direction for returning the force to the original magnitude again. The gradient non-equilibrium region can be continuous and provided between the equilibrium region and the equilibrium region.

  As a result, the moving support frame portion 23 is subjected to a temporary fluctuation in the moving speed and a light impact caused by the movement when returning to the equilibrium region from the equilibrium region. Therefore, the user who is operating the operation handle 40 can know the height position of the moving support frame 23.

  Further, at the position where the direction of inclination changes within the non-equilibrium region, the force around the cam follower member 59 is in an equilibrium state. Therefore, by setting this position in advance, the support frame portion 23 can be easily stopped at a desired height position. As such a height position, for example, there is an intermediate position of the vertical stroke of the support frame portion 23.

  Furthermore, the article support device 20 of the present embodiment holds the support frame portion 23 at a desired height position even when a force such as vibration or impact is applied from the outside, and can be easily moved or stopped by a simple operation. The brake mechanism which can be made to have is provided. The brake mechanism includes a brake device 39 of the support frame portion 23 and a first brake rail 30 of the fixed frame portion 22.

  As shown in FIG. 16, the brake device 39 is disposed slightly in front of the upper frame 36 of the support frame portion 23, slightly parallel to the brake device 39, and immediately behind the first brake rail 30 of the fixed support frame portion 22. The transmission plate 71 extends in the left-right direction. The transmission plate 71 is attached integrally by fixing the left and right ends to the upper ends of the left and right transmission rods 41 using, for example, an appropriate stay 72.

  Each transmission rod 41 is attached to the left and right guide frames 34 and 35 of the adjacent support frame portion 23 so as to be relatively movable up and down within a predetermined range. Specifically, the transmission rod 41 and the transmission plate 71 can be moved up and down between a home position shown in FIG. 17, an upward release position shown in FIG. 18, and a downward release position shown in FIG.

  At least one of the transmission rods 41 is integrally provided with a rack 73, and a pinion 74 that meshes with the rack is coaxial with a spring shaft 75 that is horizontally mounted between the guide frames so as to be rotatable in the axial direction. It is attached as a unit. A return spring 76 made of, for example, a coil spring for urging the transmission rod 41 upward via the pinion 74 and the rack 73 is gently wound around the spring shaft 75. One end 76 a of the return spring 76 is engaged with a claw 75 a on the spring shaft 75 so as to urge the transmission rod 41 upward, and the other end 76 b is engaged with the guide frame according to the rotational position of the spring shaft 75. A stop part (not shown) is detachably provided.

  In the home position of FIG. 17, the return spring 76 has the other end 76 b engaged with the locking portion and urges the transmission rod 41 and the transmission plate 71 upward. When the operation handle 40 is pushed down by hand to move the transmission rod and transmission plate from the home position to the downward release position in FIG. 19, the other end 76b of the return spring 76 is still engaged with the locking portion. . Thereafter, when the hand is released from the operation handle, the transmission rod and the transmission plate move upward by the urging force of the return spring 76 and return to the home position.

  Conversely, when the operating handle 40 is pushed up by hand and moved from the home position to the upward release position in FIG. 18, the other end 76b of the return spring 76 releases the engagement with the locking portion, and the return spring The bias is lost. Thereafter, when the hand is released from the operation handle, the transmission rod and the transmission plate are lowered by their own weight, and returned to the home position where the urging force of the return spring can be obtained again and stopped.

  A pair of transmission pins 77 a, 77 b, 78 a, 78 b are integrally projected from the transmission plate 71 toward the front in a symmetrical manner with respect to the first brake rail 30. The transmission pins 77a, 77b, 78a, 78b are arranged just outside the first brake rail 30, and the pairs are spaced apart from each other at a certain distance.

  A pair of support shafts 79 a, 79 b, 80 a, and 80 b are integrally formed on the upper frame 36 of the support frame portion 23 on the outer side of the transmission pin and symmetrically with respect to the first brake rail 30. Projected. The upper support shafts 79a and 80a are disposed below the upper transmission pins 77a and 78a, and the lower support shafts 79b and 80b are disposed above the lower transmission pins 77b and 78b. The ends of the respective support shafts are inserted through holes (not shown) formed in the transmission plate 71 and extend to the front of the transmission plate. The punch hole of the transmission plate 71 is formed to be sufficiently large so as not to prevent the transmission plate from moving up and down by the operation handle 40 described above.

  Brake arms 81a, 81b, 82a, and 82b are pivotally attached to the tips of the respective support shafts 79a, 79b, 80a, and 80b protruding from the entire surface of the transmission plate 71 along the plane of the transmission plate 71. Has been. The upper brake arms 81a and 82a are located above the upper transmission pins 77a and 78a whose tip portions are adjacent to each other, and the lower brake arms 81b and 82b are the lower transmission pins 77b and 78b whose tip portions are adjacent to each other. It arrange | positions so that it may be located below.

  Gear parts 83a, 83b, 84a, 84b are formed on the outer periphery of the base end of each brake arm, and the gear parts of the upper and lower pairs of brake arms 81a, 81b and 82a, 82b mesh with each other. Yes. Thus, when one of the pair of brake arms is rotated, the other is interlocked and rotated in the opposite direction.

  Brake shoes 85a, 85b, 86a, 86b are provided at the tips of the respective brake arms. The tip ends of the upper and lower pairs of brake arms 81a, 81b and 82a, 82b are interposed between them by tension springs 87a, 87b, and are thereby biased in a direction approaching each other. The brake shoes are pressed against the side surface of the first brake rail 30 at the home position in FIG. 17 by the urging force of the tension springs 87a and 87b. The spring strength of each of the tension springs may cause a sufficient frictional resistance between the brake shoe and the side surface of the first brake rail 30 so that the support frame portion 23 to which the article B is attached is not easily moved from the stationary position. Set to

  When the operation handle 40 is lifted and the transmission plate 71 is moved to the upwardly open position shown in FIG. 18, the upper transmission pins 77a and 78a abut against the side edges of the upper brake arms 81a and 82a, which are pulled by the tension springs 87a, It is rotated upward and outward against the urging force of 87b. In conjunction with this, the lower brake arms 81b and 82b rotate downward and outward. As a result, the engagement between each brake shoe and the side surface of the first brake rail 30 is released, so that the operation handle 40 can be lifted and the support frame portion 23 can be freely moved upward.

  Conversely, when the operation handle 40 is pulled down and the transmission plate 71 is moved to the downward open position shown in FIG. 19, the lower transmission pins 77b and 78b abut against the side edges of the lower brake arms 81b and 82b. Is rotated outwardly against the urging force of the tension springs 87a and 87b. In conjunction with this, the upper brake arms 81a and 82a rotate upward and outward. As a result, the engagement between each brake shoe and the side surface of the first brake rail 30 is released, so that the operation handle 40 can be pulled down and the support frame portion 23 can be freely moved downward.

  Since the support frame portion 23 can be moved up and down with a relatively small force, when the user operates the operation handle 40 with an unexpectedly strong force, the support frame portion 23 cannot be stopped at a desired position, or the buffer mechanism is sufficient. There is a risk of moving at such a high speed that a slow deceleration buffer effect cannot be obtained. In order to solve such a problem, the article support device 20 of this embodiment further includes a speed limiter mechanism for suppressing or limiting the moving speed of the support frame portion 23.

  As shown in FIG. 20, the speed limiter mechanism 90 according to this embodiment includes a centrifugal brake device 100 provided on the support frame portion 23 and a second brake rail 92 provided on the fixed frame portion 22. The second brake rail 92 is disposed on the rear side of the first brake rail 30 of the fixed frame portion, and extends vertically downward from the center of the upper frame 26 so as to sufficiently cover the vertical stroke of the support frame portion. doing. The second brake rail 92 has a U-shaped cross section that opens to the front side, and a rack 92a extending in the vertical direction is integrally formed on one inner side surface thereof.

  The centrifugal brake device 100 is disposed between a central plate 91 and a second brake rail 92 that extend vertically between the upper frame 36 of the support frame portion 23 and the upper lower frame 37a. The centrifugal brake device 100 includes a circular frame 101 fixed to the back surface of a central plate 91, and a rotating plate 102 rotatably supported on a central shaft 103a in the circular frame. The rotating plate 102 has a pair of parallel long sides and a pair of arcuate short sides, and a small gear 103 is integrally provided at the center thereof and concentrically with the central axis 103a of the circular frame. .

  As shown in FIG. 21 (a), a pair of brake arms 104a and 104b on one of the short sides of the rotating plate 102 are swingable around the support shafts 105a and 105b at the base end portions. And it is attached left-right symmetrically about the long side direction of the rotation plate. The brake arms 104a and 104b each have a semicircular arc shape that curves along the inner peripheral surface of the circular frame 101, and are urged in a direction approaching each other by a tension spring 107 interposed therebetween. Each brake arm 104a, 104b has a pin 109a, 109b projecting from its free end inserted into a long hole 108a, 108b formed in the rotating plate 102, thereby limiting the swingable range. .

  Brake shoes 106a and 106b are attached to the brake arms 104a and 104b, respectively, with at least a part protruding from the outer peripheral edge of the brake arm toward the inner peripheral surface of the circular frame 101. When the centrifugal brake device 100 is not in operation, the brake shoes 106a and 106b are not in contact with the inner peripheral surface of the circular frame 101 as shown in FIG. As shown in (2), it is arranged so as to be able to engage with the inner peripheral surface of the circular frame.

  As shown in FIG. 20, a gear member 93 is provided between the centrifugal brake device 100 and the second brake rail 92 so as to be rotatable around a central shaft 93 b fixed to the central plate 91. . The gear member 93 includes a pinion 94 formed of a small gear concentrically with the central shaft 93b and a large gear 95 provided along the outer periphery. The gear member 93 is mounted such that the pinion 94 meshes with the rack 92 a of the second brake rail 92 and the large gear 95 meshes with the small gear 103 of the rotating plate 102.

  When the support frame portion 23 is raised and lowered, the gear member 93 is rotated by the rack 92 a and the pinion 94, whereby the rotating plate 102 is rotated at a high speed according to the gear ratio between the large gear 95 and the small gear 103. The rotational speed of the rotating plate 102 increases or decreases depending on the lifting speed of the support frame portion 23.

  When the support frame portion 23 is stationary or moving at a very low speed, the brake arms 104a and 104b of the centrifugal brake device 100 are positioned as shown in FIG. 21 (a) by the urging force of the tension spring 107. Does not rock at all. Therefore, since it does not contact the inner peripheral surface of the circular frame 101, the support frame portion 23 can be moved at a low speed as it is.

  As the moving speed of the support frame portion 23 increases, the brake arms 104a and 104b begin to separate against the urging force of the tension spring 107. When the moving speed of the support frame portion is relatively low and the swing of the brake arm is small, the brake shoe does not come into contact with the inner peripheral surface of the circular frame 101 and the support frame portion 23 is moved as it is. be able to.

  When the moving speed of the support frame portion 23 is increased to a certain degree or more, the brake arm largely separates against the urging force of the tension spring 107, and each brake shoe has the circular shape as shown in FIG. It comes in contact with the inner peripheral surface of the frame. Therefore, the movement of the support frame portion 23 is decelerated in accordance with the magnitude of friction between the brake shoe and the inner peripheral surface of the circular frame. When the movement of the support frame portion 23 is decelerated to a certain extent, the brake arms approach each other by the tension spring 107, and the brake shoes are released from contact with the inner peripheral surface of the circular frame. Therefore, the support frame part 23 can be smoothly moved at the decelerated speed.

  When the moving speed of the support frame portion 23 is further increased, the brake arm is separated to the maximum against the biasing force of the tension spring 107, and the brake shoes are strongly pressed against the inner peripheral surface of the circular frame. The Therefore, the support frame part 23 is greatly decelerated and can be stopped depending on the case. When the movement of the support frame portion 23 is decelerated or stopped to a certain extent, the brake arms are similarly moved toward each other by the tension spring 107, and the brake shoes are released from contact with the inner peripheral surface of the circular frame. Accordingly, the support frame portion 23 can be moved smoothly or again at the reduced speed.

  As described above, in this embodiment, the speed limiter mechanism 90 described above can suppress or limit the moving speed of the support frame portion 23. Therefore, the support frame portion can be moved by careless operation of the user. It is possible to eliminate the possibility that the stop cannot be controlled. Therefore, the safety can be further enhanced particularly when supporting heavy objects such as a large TV monitor.

  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. Furthermore, in addition to the tension 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 Load support mechanism 2 Fixed part 3 Article support part 4 Spring 5 Spring force transmission member 6 1st movable cam 7 2nd movable cam 8 Fixed cam 9 Cam follower 10 1st side support part 11 2nd side support part 12 1st Movable cam surface 13 Second movable cam surface 14 Lateral cam surface 20 Article support device 21 Stand 22 Fixed frame portion 23 Support frame portion 24, 25 Spring portion 26 Upper frame 27 Lower frame 28, 29 Side frame 30 First brake rail 31 Slide rail 34, 35 Guide frame 36 Upper frame 37a, 37b Lower frame 39 Brake device 40 Operation handle 41 Transmission rod 43, 44 Tension coil spring 46 First movable cam members 46a, 46b First cam plates 47, 48 First movable cam Surface 49 Second movable cam members 49a, 49b Second cam plates 50, 5 Second movable cam surfaces 52, 53 Fixed cam members 52a, 52b, 53a, 53b Third cam plates 57, 58 Sideways cam surfaces 90 Speed limiter mechanism 91 Center plate 92 Second brake rail 92a Rack 93 Gear member 94 Pinion 100 Centrifugal brake Device 101 Circular frame 102 Rotating plates 104a, 104b Brake arms 106a, 106b Brake shoes 107 Tension spring E Extension region L1 Upper buffer region L2 Lower buffer region M1 Upper stopper region N1, N2 Buffer region

Claims (6)

A support member for supporting a load, movable within a predetermined range along a predetermined direction;
One end is fixed, the other end resists the load, exerts a biasing force on the support member in a direction along the movement direction, and a spring member disposed on one side with respect to the movement direction of the support member;
With cam followers,
Inclined at a predetermined angle with respect to the direction of the urging force, abuts against the cam follower, transmits the load and the urging force between the support member and the other end of the spring member, and together with them, moves in the moving direction. A movable cam surface that is displaced along,
A fixed cam surface that is inclined at a predetermined angle with respect to the direction of the biasing force and abuts the cam follower;
A side support portion that generates a reaction force that restricts displacement of the movable cam surface in a direction orthogonal to the direction of the biasing force with respect to the load and / or the biasing force;
The pressing force of the fixed 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 in the predetermined range in which the support member can move, and at least the biasing force. A component in a second direction orthogonal to the direction,
The movable cam surface and the fixed cam surface are moved around the cam follower, the biasing force of the spring member, the pressing force of the fixed cam surface to the cam follower, and the movable cam surface of the side support portion. The load support mechanism is designed so that the reaction force is balanced in the predetermined range in which the support member is movable. Each of the support member, the spring member, the cam follower, the movable cam surface, the fixed cam surface, and a plurality of support mechanisms comprising the side support portion,
The load support mechanism according to claim 1, wherein the plurality of support mechanisms share a common support member. Each of the support member, the spring member, the cam follower, the movable cam surface, the fixed cam surface, and the side support portion includes a first support mechanism and a second support mechanism,
2. The load support mechanism according to claim 1, wherein the first support mechanism and the second support mechanism share each of the support members and are arranged symmetrically with respect to the moving direction of the support member. The movable cam surface is inclined with respect to the direction of the biasing force, is in contact with the cam follower, and is inclined with respect to the direction of the biasing force, and a first movable cam surface that transmits the load to the spring member side. And a second movable cam surface that contacts the cam follower and transmits the urging force to the support member side,
A first side support portion that generates a reaction force that restricts displacement in a direction perpendicular to the direction of the biasing force with respect to the first movable cam surface; and the second movable cam surface. The load support mechanism according to claim 1, further comprising a second side support portion that generates a reaction force that restricts the displacement in a direction orthogonal to the direction of the biasing force.   5. The load support mechanism according to claim 4, wherein the first movable cam surface and the second movable cam surface are disposed so as to be inclined in opposite directions and to face each other with the cam follower interposed therebetween. .   6. The load support mechanism according to claim 1, wherein the spring member is a tension spring.

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