JP2015075231A - 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: An article supporting device 1 includes a base member 2, a supporting member 3, a spring member 4, a spring force transmitting member 5, a linear operation mechanism composed of a spring seat plate 6 and an adjustment screw shaft 10, and a cam follower member 7. The cam follower member is pressed to a downward cam face 15 of the supporting member, an upward cam face 18 of the spring force transmitting member, and a lateral cam face 22 of the base member by a load of an article and a spring force of the spring member. A height position of the spring member is adjustable by the spring seat plate 6 in the base member at one end 4a, and the other end 4b biases the spring force transmitting member vertically upward. A pressing force to the cam follower member, of the lateral cam face includes a vertical component according to a height position of the supporting member. Each of the cam faces is designed so that the load, the spring force and the pressing forces to the cam follower member from the cam faces, acting around the cam follower member 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 for supporting a load of an article or the like, which has a relatively simple structure, a small number of parts, a small size, and An object of the present invention is to provide a load support mechanism that is lightweight and can support an object having a different load at a desired position and in a displaceable manner without replacing components or the entire apparatus.

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

  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, within a predetermined range in which the support member can be moved, the support member can be held at a desired position while the load is supported, and can be easily moved with a small force.

  In addition, the load support mechanism of the present invention can adjust the initial biasing force of the spring member by adjusting the position of the one end of the spring member along the direction of the biasing force, and even for loads of different sizes. Since the first cam surface and the second cam surface maintain the equilibrium state around the cam follower, the support member can be held at a desired position and held movably. Moreover, it is advantageous for the variation in the magnitude of the load because it is not necessary to replace the first cam surface, the second cam surface or the spring member or the entire device.

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

  In one embodiment, in the predetermined range in which the second cam surface can move the support member, the first direction component of the pressing force to the cam follower of the second cam surface acts in the direction of the biasing force. 1 region, and a second region in which the component in the first direction of the pressing force of the second cam surface to the cam follower acts in the direction opposite to the direction of the urging force. If comprised in this way, the magnitude | size of the inclination with respect to the direction of the said urging | biasing force of a 2nd cam surface does not become large too much or either of a 1st area | region or a 2nd area | region. Therefore, when moving the support member to a desired position, the cam follower can be smoothly driven over the entire second cam surface.

  In another embodiment, the load support mechanism further includes a fixing member that fixes the one end of the spring member so that the position thereof can be adjusted along the direction of the biasing force and has a side support portion. Thereby, the configuration of the entire apparatus can be simplified and the number of parts can be reduced.

FIG. 1 is a perspective view of an embodiment of a load support mechanism according to the present invention. FIG. 2 is an exploded perspective view of this embodiment. FIG. 3 is a longitudinal sectional view of this embodiment in which the mounting plate is in the uppermost position in the standard mode. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a diagram illustrating the relationship between the main parts in FIG. FIG. 6 is an explanatory view similar to FIG. 5 when the mounting plate is in the intermediate position. FIG. 7 is an explanatory view similar to FIG. 5 when the mounting plate is in the lowest position. FIG. 8 is a longitudinal sectional view similar to FIG. 3 in the lightweight mode. FIG. 9 is a longitudinal sectional view similar to FIG. 3 in the weight mode.

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

  1 and 2 schematically show an article support device 1 which is a preferred embodiment of a load support mechanism according to the present invention. As shown in FIG. 1, the article support device 1 of this embodiment includes a base member 2, a support member 3, a spring member 4 including a compression coil spring, a spring force transmission member 5, and a cam follower member 7. . Further, the article support device 1 includes a linear operation mechanism (to be described later) formed by combining a spring seat plate 6 with a nut and an adjusting screw shaft 10.

  The base member 2 has a rectangular cylindrical fixed column 8 that extends in the vertical direction and opens upward. A base plate 9 is integrally provided at the lower end of the fixed column 8 in order to install the article support device 1 on a floor surface or a work table surface.

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

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

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

  On a pair of opposing side surfaces 8a of the fixed column 8, second cam grooves 21 having the same shape and dimensions extending in the vertical direction are formed at opposing positions. The second cam groove 21 has a lateral cam surface 22 composed of an end surface on the left side, that is, the side facing the upward cam surface 18 and the downward cam surface 15 in FIG. The lateral cam surface 22 is curved in a convex shape toward the right in the drawing, that is, toward the upward cam surface 18 and the downward cam surface 15 so that the inclination in the tangential direction changes over the entire length from the upper end to the lower end or partially. doing.

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

  The spring seat plate 6 has a flat plate shape having substantially the same rectangular shape and dimensions as the cross section of the inner hole 8b of the fixed column 8, and a circular shallow spring receiving surface 6a for receiving the lower end of the spring member on the upper surface thereof. It is recessed. At the center of the spring seat plate 6, a nut portion 19 having a female screw portion is erected integrally vertically upward. Further, the spring seat plate 6 has a small protrusion 20 protruding outward from the center of one side.

  The adjustment screw shaft 10 has a relatively long screw portion 23 and a hexagonal columnar head portion 24. As shown in FIG. 3, a through hole 25 having a diameter slightly larger than the outer diameter of the shaft portion of the adjusting screw shaft 10 is formed at the center of the bottom plate of the inner hole 8 b of the fixed column 8. The adjusting screw shaft 10 is prevented from coming off by a double nut in which the screw portion 23 is inserted into the through-hole 25 upward from the lower side, and two set nuts 28 are screwed onto the base end of the screw portion from the inner hole 8b side. By doing so, it is rotatably attached to the bottom plate of the inner hole 8b.

  The fixed column 8 is provided with a guide groove 29 extending vertically from the upper end to the lower end on the inner surface of one side wall 8c adjacent to the side surface 8a. The spring seat plate 6 is arranged in the inner hole 8b of the fixed column 8 so that each side is aligned with the inner wall of the inner hole, and the protrusion 20 is fitted in the guide groove 29, so that the nut portion 19 is fitted to the adjusting screw shaft 10. The screw part 23 is screwed and arranged. Since each side of the spring seat plate 6 is constrained by the inner wall of the inner hole 8b and cannot be rotated, when the adjusting screw shaft 10 is rotated, the spring seat plate 6 moves up and down according to its direction. Thus, according to the present embodiment, the linear operation mechanism for continuously adjusting the height position of the spring seat plate 6 is obtained.

  When the adjustment screw shaft 10 is rotated, the set nut 25 rotates integrally with the adjustment screw shaft while being in sliding contact with the bottom surface of the inner hole 8b of the fixed column 8. If an appropriate friction reducing means such as a low friction washer or a thrust bearing is interposed between the lock nut 25 and the bottom surface of the inner hole 8b, friction that prevents smooth rotation of the adjusting screw shaft 10 and wear on the contact surface are eliminated. Or because it is reduced.

  In the guide groove 29 of the fixed column 8, a through window 30 made of a straight groove is formed at the lower part thereof. Through the through window 30, the protrusion 20 of the spring seat plate 6 can be easily seen from the outside. When the protrusion 20 moves up and down in the guide groove 29 together with the spring seat plate 6, the height position of the spring seat plate can be determined from the through window 30.

  The side surface 8c of the fixed column 8 is preferably provided with a scale indicating the height position of the spring seat plate 6 corresponding to the magnitude of the load applied to the article support device 1 along the through window 30. For example, if the load of the article that can be placed on the article support device 1 is set to 1.5 to 2.5 kg, the through window 30 is formed in accordance with the range, and the corresponding scale and / or numerical display May be provided.

  The spring member 4 is disposed in the inner hole 8b of the fixed column 8 of the base member 2 so that the lower end thereof is in contact with the spring receiving surface 6a of the spring seat plate 6 and expands and contracts in the vertical direction. The movable column 11 having the spring force transmission member 5 mounted in the inner hole 11b is inserted from above the spring member 4 into the inner hole 8b of the fixed column 8 so as to be relatively movable in the vertical direction. The spring force transmission member 5 is mounted so that the upper end of the spring member 4 is brought into contact with the upper end surface of the inner hole 15a of the slide portion 15 and is urged upward by the spring member.

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

  The cam follower member 7 is inserted horizontally through the first cam groove 14 and the second cam groove 21 and is horizontally disposed on the upper side of the cam 17, and its outer peripheral surface is in contact with the downward cam surface 15, the upward cam surface 18 and the lateral cam surface 22. It is mounted so that it touches. At this time, the rolling bearing fitted to the rod of the cam follower member 7 is rolling bearing 71 with respect to the downward cam surface 15, rolling bearing 72 with respect to the upward cam surface 18, and rolling with respect to the lateral cam surface 22. Each of the bearings 73 is disposed and is individually brought into contact with the corresponding cam surface. Moreover, it is preferable to attach a suitable retaining ring to both ends of the cam follower member 7 protruding outward from the second cam groove 22 to prevent the cam follower member 7 from coming off.

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

  Next, the operation and function of the article support apparatus 1 will be described. In the following description, as described above, it is assumed that the load of the article that can be placed on the article support device 1 is in the range of 1.5 to 2.5 kg, and the case where the load of the article is 2 kg is the standard mode, the minimum use load. The case of 1.5 kg is a light mode, and the case of a maximum use load of 2.5 kg is a weight mode.

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

  FIG. 3 shows a case where the placing plate 12 on which the article A with a load W is placed in the uppermost position in the standard mode. The cam follower member 7 is stationary at the upper limit position of the first region S1 of the lateral cam surface 22.

  FIG. 5 schematically shows an equilibrium state of forces acting on the system including the cam follower member 7, the fixed column 8, the movable column 11 and the spring force transmission member 5 at the upper limit position. In order to simplify the description, the load of the support member 3 and the spring force transmission member 5 and the frictional force between the movable column 11 and the fixed column 8 and the spring force transmission member are omitted. In an actual design, it goes without saying that these factors must be taken into consideration, and the load of the support member and the spring force transmission member is composed of the cam follower member, the fixed column, the movable column, the spring force transmission member, and the cam plate. 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 member 4 composed of a compression coil spring having a spring constant k is expressed by the displacement x in the axial direction of the compression coil spring (displacement from the free length of the spring, that is, the length of the unloaded state: Fs = k · x. In order to be able to support the article A at the uppermost position, at the upper limit position of the stroke, the compression coil spring is pre-compressed by a predetermined initial displacement amount x0 from the free length, and already has an initial spring force (Fs0 = k -It is configured to exhibit x0). The same applies to the case where the height position of the spring seat plate 6 is changed by rotating the adjusting screw shaft 10 in accordance with the load to be supported.

  In FIG. 5, at the contact point Pa between the cam follower member 7 and the downward cam surface 15, the load W of the article A, the reaction force Ra acting in the normal direction of the downward cam surface 15 from the cam follower member 7, and movable from the fixed column 8. The horizontal reaction force Rd1 acting on the column 11 is balanced. The magnitude of the vertical component Ra1 of the reaction force Ra is equal to the magnitude of the load W, and the magnitude of the horizontal component Ra2 is equal to the reaction force Rd1 from the fixed column 8. A force Fa that presses the cam follower member 7 from the downward cam surface 15 is a resultant force of the load W and the reaction force Rd1.

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

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

When the cam follower member 7 is stationary at a certain position on the lateral cam surface 22, the force acting direction is positive in the vertical direction between the load W, the spring force Fs, and the vertical component Rc1 of the reaction force Rc. The following relationship always holds in theory.
W + Fs + Rc1 = 0
In the actual design, 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 spring force Fs of the spring member 4 is the minimum initial spring force (Fs0 = k · x0), which is smaller than the magnitude of the load W. Accordingly, the vertical force component Rc1 of the reaction force Rc acting upward from the lateral cam surface 22 is applied as an assist force to the spring force Fs, thereby realizing the balance with the load W in the vertical direction. In this state, when the article A or the mounting plate 12 is pushed down by hand, the pushing force is added to the load W and the balance is lost, so that the article can be easily lowered with a relatively small force.

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

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

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

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

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

  In the standard mode, when the mounting plate 12 on which the article A having the load W is loaded is pushed down from the uppermost position in FIG. 3 to the intermediate position, the cam follower member 7 is moved to the lateral cam surface as indicated by an imaginary line 7 ′ in FIG. It is located within the range of 22 second region S2. FIG. 6 schematically shows an equilibrium state of forces acting on a system including the cam follower member 7, the fixed column 8, the movable column 11, and the spring force transmission member 5 at this intermediate position. Similarly, for simplification, the load of the support member 3 and the spring force transmission member 5 and the frictional force between the movable column 11 and the fixed column 8 and the spring force transmission member will be omitted.

  As in the case of FIG. 5, at the contact point Pa between the cam follower member 7 and the downward cam surface 15, the load W of the article A, the reaction force Ra acting in the normal direction of the downward cam surface 15 from the cam follower member 7, and the fixed The horizontal reaction force Rd1 acting on the movable column 11 from the column 8 is balanced. The magnitude of the vertical component Ra1 of the reaction force Ra is equal to the load W, and the magnitude of the horizontal component Ra2 is equal to the reaction force Rd1 of the fixed column 8. A force Fa acting on the cam follower member 7 from the downward cam surface 15 is a resultant force of the load W and the reaction force Rd1.

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

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

  Thus, when the cam follower member 7 is located in the range of the second region S2 of the lateral cam surface 22, the spring force Fs and the load W of the spring member 4 are substantially balanced in the vertical direction. Therefore, the spring force Fs does not require an assist force due to the reaction force Rc from the lateral cam surface 22. Even in this state, by pushing down or pushing up the article A or the mounting plate 12 by hand, the force is added to the load W or the spring force Fs, and the balance is broken. Therefore, the article can be easily made with a relatively small force. Can be moved up and down.

  Similarly, in the standard mode, when the mounting plate 12 on which the article A having the load W is loaded is pushed down to the lowest position, the cam follower member 7 is moved to the third side of the lateral cam surface 22 as indicated by an imaginary line 7 ″ in FIG. Fig. 7 schematically shows an equilibrium state of forces acting on the system including the cam follower member 7, the fixed column 8, the movable column 11, and the spring force transmission member 5 at the lower limit position of the region S3. Similarly, for simplification, the load of the support member 3 and the spring force transmission member 5 and the frictional force between the movable column 11 and the fixed column 8 and the spring force transmission member will be omitted.

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

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

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

  When the cam follower member 7 is at the lower limit position of the third region S3 of the sideways cam surface 22, the displacement of the spring member 4 is maximum, the spring force Fs is maximum, and the magnitude thereof is larger than the load W. Therefore, the vertical component Rc1 of the reaction force Rc acting downward from the lateral cam surface 22 acts in a direction to reduce the upward biasing force, that is, the push-up force by the spring force Fs. The equilibrium is realized.

  Even in this state, when the article A or the mounting plate 12 is pushed up by hand, the pushing force is added to the spring force Fs and the balance is broken, so that the article can be easily raised with a relatively small force. . When the mounting plate 12 is raised, the cam follower member 7 moves upward while being displaced in the left-right direction along the lateral cam surface 22, the downward cam surface 15, and the upward cam surface 18. While the cam follower member 7 is within the range of the third region S3 of the lateral cam surface 22, the downward vertical component Rc1 of the reaction force Rc reduces the push-up force due to the spring force Fs of the spring member 4 and balances with the load W. Acts in the direction.

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

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

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

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

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

  According to the present embodiment, the load W of the article A acting on the system including the cam follower member 7, the fixed column 8, the movable column 11, and the spring force transmission member 5 and the spring of the spring member 4 in the entire region of the lateral cam surface 22. The force Fs, the reaction force from the fixed column 8 and the reaction force from the lateral cam surface 22 are balanced around the cam follower member 7. As a result, the placement plate 12 on which the article A is placed can be kept stationary at a desired height position within the range of the vertical stroke, the position can be maintained, and the plate can be easily raised and lowered with a relatively small force.

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

  FIG. 8 shows the article support apparatus 1 set to the lightweight mode. The lightweight mode is set by rotating the adjusting screw shaft 10 to lower the spring seat plate 6 to the bottom surface of the inner hole 8b of the fixed column 8. As in the case of the standard mode of FIG. 3, the lateral cam surface 22 will be described by dividing it into a first region S1, a second region S2, and a third region S3.

  The figure shows a case where the mounting plate 12 on which the article A is placed is at the uppermost position. The cam follower member 7 is stationary at the upper limit position of the first region S1 of the lateral cam surface 22. In this position, the system comprising the cam follower member 7, the fixed column 8, the movable column 11 and the spring force transmission member 5 includes a load W of the article A, a spring force Fs of the spring member 4, a reaction force from the fixed column 8, and The reaction force from the lateral cam surface 22 acts and balances around the cam follower member 7.

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

  When the placement plate 12 on which the article A is placed is pushed down from the uppermost position in FIG. 8 to the intermediate position, the cam follower member 7 is moved to the second region S2 of the lateral cam surface 22 as indicated by an imaginary line 7 ′ in FIG. Located within range. Even at this intermediate position, the system comprising the cam follower member 7, the fixed column 8, the movable column 11 and the spring force transmission member 5 has a load W of the article A, a spring force Fs of the spring member 4, a reaction force from the fixed column 8, The reaction force from the lateral cam surface 22 acts and balances around the cam follower member 7.

  In the second region S2, as described with reference to FIG. 6 for the standard mode, the reaction force Rc from the lateral cam surface 22 is substantially only a horizontal component and has no vertical component. In the vertical direction, the spring force Fs of the spring member 4 and the load W are substantially balanced.

  When the placement plate 12 on which the article A is placed is pushed down to the lowest position, the cam follower member 7 stops at the lower limit position of the third region S3 of the lateral cam surface 22 as indicated by an imaginary line 7 "in FIG. Even at this position, the system comprising the cam follower member 7, the fixed column 8, the movable column 11 and the spring force transmitting member 5 has a load W of the article A, a spring force Fs of the spring member 4, a reaction force from the fixed column 8, The reaction force from the lateral cam surface 22 acts and balances around the cam follower member 7.

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

  FIG. 9 shows the article support apparatus 1 set to the weight mode. The weight mode is set by rotating the adjustment screw shaft 10 and raising the spring seat plate 6 to a predetermined uppermost position. Here again, the lateral cam surface 22 will be described by dividing it into a first region S1, a second region S2, and a third region S3.

  The figure shows a case where the mounting plate 12 on which the article A is placed is at the uppermost position. The cam follower member 7 is stationary at the upper limit position of the first region S1 of the lateral cam surface 22. In this position, the system comprising the cam follower member 7, the fixed column 8, the movable column 11 and the spring force transmission member 5 includes a load W of the article A, a spring force Fs of the spring member 4, a reaction force from the fixed column 8, and The reaction force from the lateral cam surface 22 acts and balances around the cam follower member 7.

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

  When the placement plate 12 on which the article A is placed is pushed down from the uppermost position in FIG. 9 to the intermediate position, the cam follower member 7 moves in the second region S2 of the lateral cam surface 22 as indicated by an imaginary line 7 ′ in FIG. Located within range. Even at this intermediate position, the system comprising the cam follower member 7, the fixed column 8, the movable column 11 and the spring force transmission member 5 has a load W of the article A, a spring force Fs of the spring member 4, a reaction force from the fixed column 8, The reaction force from the lateral cam surface 22 acts and balances around the cam follower member 7.

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

  When the placement plate 12 on which the article A is placed is pushed down to the lowest position, the cam follower member 7 stops at the lower limit position of the third region S3 of the lateral cam surface 22 as indicated by an imaginary line 7 "in FIG. In this position, the system comprising the cam follower member 7, the fixed column 8, the movable column 11, and the spring force transmission member 5 includes a load W of the article A, a spring force Fs of the spring member 4, a reaction force from the fixed column 8, The reaction force from the lateral cam surface 22 acts and balances around the cam follower member 7.

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

  In the lightweight mode, since the load W of the article A is smaller than that in the standard mode, if the initial displacement amount and the initial spring force of the spring member 4 are the same as those in the standard mode, the force that pushes up the article A relatively increases. Therefore, it is necessary to make the biasing force of the spring member 4 smaller than that in the standard mode in all the regions S1 to S3 of the lateral cam surface 22.

  On the other hand, in the weight mode, the load W of the article A is larger than that in the standard mode. Therefore, if the initial displacement amount and the initial spring force of the spring member 4 are the same as those in the standard mode, Get smaller. For this reason, in all the regions S1 to S3 of the lateral cam surface 22, the urging force of the spring member 4 needs to be larger than that in the standard mode.

  In the present embodiment, as described above, the adjustment screw shaft 10 is rotated to adjust the height position of the spring seat plate 6, thereby changing the initial displacement amount and the initial spring force of the spring member 4. Correspondence to the light weight mode and the heavy weight mode is realized without replacing the spring member and / or other components or replacing the article support device 1 itself. In addition, the cam profile of the sideways cam surface 22 allows the mounting plate 12 on which the article is placed to rest at a desired height in the entire range of the first to third regions even if the height position of the spring seat plate 6 is changed. It is designed and formed to be able to.

  The means for adjusting the height position of the spring seat plate 6 is not limited to the linear operation mechanism of the present embodiment, and various known mechanisms and structures can be used. Further, in order to support the lower end of the spring member 4 in the fixed column 8, a structure other than the spring seat plate can be adopted, and in this case, the end position of the spring member is determined by a method different from the linear operation mechanism. Needless to say, it can be adjusted.

  The above description is made for the case where the load W of the article is 1.5 kg, 2 kg, and 2.5 kg in the present embodiment. However, the present embodiment is naturally an article that can be placed on the article support device 1. It can be similarly applied in the load range. The lateral cam surface 22 has a cam profile that allows the mounting plate 12 on which articles are placed in the entire region to be stationary at a desired height when the spring seat plate 6 is set at a predetermined height position in accordance with the load to be supported. Designed and formed.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications or changes can be made within the technical scope. For example, the downward cam surface of the movable column and the lateral cam surface of the fixed column 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 fixed column The cam surface can be designed for various cam profiles. Furthermore, in addition to the compression coil spring described above, the spring member has a different shape such as a leaf spring and a spiral spring, a fluid spring such as an air spring, an elastic material such as rubber, and other non-metallic materials, etc. Various known springs can be applied.

DESCRIPTION OF SYMBOLS 1 Article support apparatus 2 Base member 3 Support member 4 Spring member 5 Spring force transmission member 6 Spring seat plate 7 Cam follower member 8 Fixed column 9 Base plate 10 Adjustment screw shaft 11 Moving column 12 Mounting plate 14 First cam groove 15 Downward cam surface 16 Slide portion 17 Cam 18 Upward cam surface 21 Second cam groove 22 Lateral cam surface

Claims (3)

A support member for supporting a load, movable within a predetermined range along a predetermined direction;
A spring member having one end fixed and the other end exerting a biasing force in the direction along the moving direction of the support member against the load;
The load member and the biasing force are transmitted between the support member and the other end of the spring member, and are disposed so as to be displaced along the moving direction together with the load and the biasing force, and at a predetermined angle with respect to the direction of the biasing force. An inclined first cam surface and a cam follower contacting the first cam surface;
A second cam surface that is inclined at a predetermined angle with respect to the direction of the urging force and is in contact with the cam follower;
A side support portion that generates a reaction force that regulates displacement in a direction orthogonal to the direction of the biasing force on the first cam surface with respect to the load and / or the biasing force;
The pressing force of the second cam surface to the cam follower includes a component in a first direction along the direction of the biasing force generated by the position of the support member within the predetermined range in which the support member can move, and at least the biasing force. A second direction component orthogonal to the direction of
The one end of the spring member can adjust its position along the direction of the biasing force;
Even if the first cam surface and the second cam surface adjust the position of the one end of the spring member, the load acting around the cam follower, the urging force of the spring member, and the second cam surface The load is designed such that the pressing force to the cam follower and the reaction force of the side support portion to the first cam surface are balanced in the predetermined range in which the support member is movable. Support mechanism.   In the predetermined range in which the second cam surface can move the support member, the first direction component of the pressing force of the second cam surface to the cam follower acts in the direction of the urging force. And a second region in which a component in the first direction of the pressing force of the second cam surface to the cam follower acts in a direction opposite to the direction of the biasing force. The load supporting mechanism according to 1.   The said one end of the said spring member is fixed further so that the position can be adjusted along the direction of the said urging | biasing force, The fixing member which has the said side support part is further provided. Load support mechanism.

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