JP6395177B2 - Load support mechanism - Google Patents

Description

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

  Conventionally, various support mechanisms have been proposed in order to support articles such as computers, television monitor devices, OA desks, work table tops, and heavy objects so that they can be raised and lowered to a desired height position. For example, 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 Documents 1 and 2).

  The monitor device support mechanism described in Patent Document 1 includes at least one cam, at least one cam driven member, an energy storage member such as a spring, a moving body for attaching the monitoring device, and a cam driven member on the moving body. And a swingable arm member to be connected. In the monitor device support mechanism, when the moving body moves along the fixed base, the spring is compressed / expanded by the cam. The spring force of the spring is converted into a reaction force against the cam follower member by the cam surface, and the first reaction force component in the moving direction of the moving body included in the reaction force is transferred to the moving body and the monitoring device via the arm member. Create support for

  According to Patent Document 1, the shape of the cam is designed so that the first reaction force component in the moving direction is kept constant. By such a combination of the spring and the cam shape, the force for biasing the moving moving body and the monitor in the moving direction is kept substantially constant. 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. Patent Document 1 discloses an adjustment mechanism for adjusting a variable load applied to the monitor device support mechanism by adjusting the interval between the cams by rotating the cams around the axis.

  Further, Patent Document 2 describes another force adjusting mechanism for adjusting a substantially constant supporting force that acts on the moving body and the monitor device. This force adjustment mechanism can support loads of various weights in the monitor device support mechanism by changing the effective length and pretension of the leaf spring that presses the cam follower (roller) against the guide surface of the cam. .

  Further, in order to support the load of the conduit etc. with a substantially constant spring biasing force, a main spring mechanism for suspending and supporting the load and an additional spring mechanism for compensating for a change in the biasing force of the main spring mechanism are provided. A suspension device provided is known (for example, see Patent Document 3). The main spring mechanism is an upper and lower main spring that is inserted between the upper head member that is externally attached to the vertical sleeve and is fixed to the upper end of the sleeve and the lower spring receiver that is fixed to the casing. And a downward load acting on the lower end of the sleeve is supported by the upward biasing force of the main spring.

  The additional spring mechanism includes a cam follower provided in the head member, a cam arm swingably attached to the casing, a cam surface formed integrally with the cam arm, and a biasing force of the cam arm in the horizontal direction to cause the cam surface to be a cam follower. A pair of additional springs that are pressed against each other are arranged symmetrically. The displacement of the sleeve in the vertical direction due to the load is canceled by the rolling of the cam follower along the curved cam surface so that the change in the biasing force of the main spring is canceled by the biasing force of the additional spring.

Japanese Patent Laid-Open No. 2002-215055 JP 2002-303304 A U.S. Pat. No. 4,613,119

  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. In addition, when supporting a monitor device such as a television set that is often arranged along the wall surface, the support device itself needs to be thinned, that is, the depth dimension is reduced, as the monitor device is thinned. Has been.

  However, in the monitor device support mechanisms described in Patent Documents 1 and 2, the coil spring of the energy storage member is arranged in a direction in which the axial direction thereof is substantially orthogonal to the moving direction of the monitor device, and the moving body is formed only by the spring force. And supporting the monitoring device. In addition, it is only the first reaction force component in the moving direction of the moving body, not the entire reaction force of the cam surface against the cam driven member that creates the force that supports the moving body and the monitor device.

  Therefore, a large coil spring that can exert a spring force considerably larger than the weight of the moving body to be supported 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. Further, the supporting force to the moving body is transmitted from the cam follower member through the swingable arm member. Therefore, in order to support a large and heavy monitor device, for example, as described in FIGS. 4A and 4 of Patent Documents 1 and 2, a thick and sturdy arm member must be used. As a result, it is difficult to reduce the thickness of the monitor device support mechanism of Patent Documents 1 and 2 because the entire device is enlarged particularly in the depth direction. In addition, since the structure is complicated, it is not possible to easily reduce the size and weight of the apparatus.

  Furthermore, the monitor device support mechanisms described in Patent Documents 1 and 2 are disclosed in these documents because the support force of the moving body and the monitor device is determined only by the combination of the spring that biases the cam follower and the cam shape. However, the force adjusting mechanism to be used may not be able to cope with a large change in the weight of the monitor device. Therefore, it may be necessary to replace the spring and the cam or replace the support mechanism itself in order to support the monitoring device having a significantly different weight. As a result, a separate support mechanism or component must be prepared for each weight of the object to be supported, resulting in a problem that the price is increased.

  The suspension device described in Patent Document 3 is merely a buffer mechanism for stably supporting a conduit at a predetermined height position. For this reason, the conduit or the like cannot be moved to a desired height position and supported in a stationary state at the height position.

  In addition, recent monitor devices tend to be heavier as the screen becomes larger. Therefore, the article support mechanism is required to have a structure that can withstand a higher load.

  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. It is an object of the present invention to provide a load support mechanism that is simple and has a small number of parts and that can be easily reduced in size, particularly reduced in thickness with a small depth dimension.

  A further object of the present invention is to provide a load support mechanism having sufficient strength to withstand a high load in addition to the above object.

The load support mechanism of the present invention includes a fixed support portion,
A movable support for receiving a load, movable within a predetermined range along a predetermined direction with respect to the fixed support;
A fixed cam provided on the fixed support portion and having a fixed cam surface;
A cam groove provided in the movable support portion, having a first movable cam surface and a second movable cam surface facing each other, and extending in a direction crossing the moving direction of the movable support portion;
A cam follower movable in the cam groove along the cam groove while being in contact with the first movable cam surface or the second movable cam surface;
A first spring interposed between the fixed support portion and the movable support portion so as to support the load;
A second spring provided on the movable support portion and biasing the cam follower toward the fixed cam surface;
The first movable cam surface is provided to transmit the load at a contact point with the cam follower,
The second movable cam surface is provided to transmit the urging force of the first spring at the contact point with the cam follower,
Fixed cam surface, along the moving direction of the movable supporting member, the reaction force against the cam follower, the Ingredient second direction including useless perpendicular to the moving direction of at least the movable support portion in contact with the cam follower, toward the cam follower side Curved in a convex shape
The curvature of the fixed cam surface is caused by the load acting on the cam follower from the first movable cam surface, the urging force of the first spring acting from the second movable cam surface , the reaction force of the fixed cam surface against the cam follower, and the cam follower. The urging force of the second spring acting in this manner is balanced around the cam follower and the movable support portion is designed to be stationary within a predetermined range.

In such a configuration, when the force acting around the cam follower is in an equilibrium state, the movable support portion is movable in the moving direction of the load, the urging force of the first spring, and the reaction force of the fixed cam surface. The component in the first direction along the moving direction of the support portion is balanced. Further, in the second direction orthogonal to the moving direction of the movable support portion, the biasing force of the second spring and the component in the second direction of the reaction force of the fixed cam surface are balanced. Accordingly, the movable support portion can be held in a state in which the load is supported at a desired position without using other components or external force.

  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. The external force acting on the certain object or member includes a frictional force generated between the certain object or member and another object or member in addition to the load of the certain object or member itself. , A frictional force or a resistance generated in another object or member that applies the external force to the certain object or member is included. In actual use, when these frictional forces are equal to or greater than the resultant force when the weight of the certain object or member and the other object or member is added to the force acting around the cam follower , Can act as a force to hold the object or member in a stationary position.

Between the fixed support with a fixed cam movable support that moves in supporting a load, the movement direction or first direction of the movable supporting member, because only the first spring and the cam follower exist, load and first power of the difference between the biasing force of the spring is directly transmitted to the fixed cam surface through the cam follower from the first or second movable cam surfaces of the cam grooves of the variable rotation support portion. On the other hand, in the second direction orthogonal to the moving direction of the movable support portion, only the second spring and the cam follower exist, so the urging force of the second spring directly acts on the fixed cam surface via the cam follower and the cam follower. the reaction force of the fixed cam face in contact, so generates a force in the first direction component in accordance with the inclination of the fixed cam face, can be utilized to effectively support the load of the urging force of the second spring. As described above, according to the present invention, it is possible to realize a load supporting mechanism that exhibits high strength structurally with a small number of parts, a smaller and simple configuration.

Since the biasing force of the first spring varies depending on the displacement, the biasing force of the first spring becomes smaller or larger than or equal to the load depending on the position of the movable support portion. According to the present invention, when there is an equilibrium state of the force around the cam follower , the component in the first direction of the reaction force from the fixed cam surface assists when the biasing force of the first spring is smaller than the load. Acts in the direction and acts in a direction to reduce this when it is larger than the load. Therefore, the movable support portion can be easily moved with a small force while being held at a desired position within a predetermined movable range while supporting the load.

  In one embodiment, each of the plurality of support mechanisms includes a fixed support portion, a movable support portion, a first spring, a second spring, a cam follower, a fixed cam, and a cam groove. The support part and the movable support part are made common. As a result, since the load of the load is distributed to the plurality of support mechanisms, it is easy to support a larger load and a heavier article in a balanced manner. Further, by sharing the fixed support portion and the movable support portion, it is possible to receive a load with a larger area and to support a longer article or the like.

  In another embodiment, the first support mechanism includes a first support mechanism and a second support mechanism each including a fixed support portion, a movable support portion, a first spring, a second spring, a cam follower, a fixed cam, and a cam groove. And the second support mechanism share the fixed support portion, the movable support portion, and the second spring, and are arranged symmetrically with respect to the moving direction of the movable support portion. Accordingly, even with a larger load, the first support mechanism and the second support mechanism can support the left and right in a balanced manner, and the movable support portion can be held and moved to a desired stationary position more stably.

  In another embodiment, the fixed support portion has outer frame portions on both sides in the movement direction of the movable support portion, and the both side portions of the movable support portion are guided in the movement direction by the outer frame portion. Configured. Since both side portions of the movable support portion are guided by the outer frame portion of the fixed support portion in this way, the entire structural strength of the movable support portion and the load support mechanism is improved. be able to.

  In one embodiment, the movable support portion has a support member extending in a direction orthogonal to the moving direction, the cam groove is provided in the support member, and the second spring is externally or internally provided on the support member. This is a compression coil spring that biases the cam follower in the extending direction of the support member. Accordingly, the second spring is supported by the support member that constitutes a part of the movable support portion, and buckling that may occur due to the compression displacement of the second spring can be prevented without providing an additional member, and the number of parts can be reduced. It can be reduced and the structure of the entire apparatus can be simplified.

  In another embodiment, the cam groove extends from near one end of the support member toward the opposite side, and a second spring is provided to bias the cam follower toward the one end of the support member. Thereby, the range which can be moved while making a cam follower contact | abut to a fixed cam surface can be set larger. As a result, the fluctuation range of the biasing force of the second spring, that is, the reaction force of the fixed cam and the fluctuation range of the first direction component can be made larger, and the movable support portion can be maintained while maintaining the equilibrium state of the force. The range that can be moved can be expanded.

In yet another embodiment, the cam follower, the front and rear pair respectively provided front and rear ends of the first cam follower member which projects a cam groove and a first cam follower member which penetrates in the longitudinal direction of the supporting support member, the cam groove The fixed cam is composed of a pair of front and rear fixed cam members that abut each of the second cam follower members. Thereby, the force acting on the cam follower from the fixed cam is distributed in a well-balanced manner along the axial direction of the first cam follower member, which is advantageous because the cam follower is stably held in the cam groove.

  Furthermore, since there is no other component between the spring support member and the front and rear fixed cam members, the axial length of the first cam follower member can be shortened, and excessive force due to reaction force from the fixed cam member can be reduced. The risk of bending, deformation, breakage, etc. can be eliminated. Also for the fixed cam, the burden on each fixed cam member is reduced due to the dispersion of the force received from the cam follower, so that they can be made thinner. Thus, by reducing the length of the first cam follower member in the axial direction and making the fixed cam member thinner, the overall device can be made thinner and lighter.

  In another embodiment, the first spring and the second spring are disposed so as to at least partially overlap each other when seen in a plan view in a direction orthogonal to the moving direction of the movable support portion. With such an arrangement, the depth dimension of the load support mechanism can be designed to be smaller, that is, thinner.

It is a front view which shows the basic composition of the load support mechanism by this invention. It is an arrow line view in the II-II line of FIG. It is a figure explaining the relationship between the principal parts in the state which has a 2nd cam follower in 1st area | region S1 of a fixed cam surface. It is explanatory drawing similar to FIG. 3 in which a 2nd cam follower exists in 2nd area | region S2 of a fixed cam surface. It is explanatory drawing similar to FIG. 3 in which a 2nd cam follower exists in 3rd area | region S3 of a fixed cam surface. It is a perspective view of the embodiment of the article support device to which the present invention is applied. FIG. 7 is an exploded perspective view of the embodiment of FIG. 6. It is a front view of the article | item support apparatus which has a support frame part in the uppermost position. It is the elements on larger scale of FIG. 8 which looked at one cam follower member from the top. FIG. 10 is a view taken along the line IX-IX in FIG. 9 with the fixed cam member omitted. It is an enlarged view which shows the lower frame and 2nd spring of the lower side of a support frame part. It is the elements on larger scale which planarly viewed the support frame part from the upper part. It is the elements on larger scale which show the fixed cam surface and cam follower member of FIG. It is a front view similar to FIG. 8 with a support frame part in an intermediate position. It is the elements on larger scale which show the fixed cam surface and cam follower member of FIG. It is a front view similar to FIG. 8 with a support frame part in the lowest position. It is the elements on larger scale which show the fixed cam surface and cam follower member of FIG. It is the elements on larger scale which show the upper end vicinity of a fixed cam surface. It is the elements on larger scale which show the lower end vicinity of a fixed cam surface. It is a partial expansion perspective view which shows the brake mechanism of this embodiment. FIG. 20 is a front view of the brake mechanism of FIG. 19. It is a front view which shows releasing operation | movement of the brake mechanism at the time of a raise. It is a front view which shows releasing operation | movement of the brake mechanism at the time of descent | fall. It is the partial crushing enlarged view which looked at the speed limiter mechanism 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 support portion 2 installed on, for example, a floor or a table, a movable support portion 3 that receives a load of an article, and a first spring 4 made of, for example, a tension coil spring. Prepare. For example, the article A which is a monitor device of a television can be attached to and supported on the front side of the load support mechanism 1 by an attachment stay 5 provided on the movable support portion 3.

  In this embodiment, the fixed support portion 2 has an outer frame structure composed of vertical left and right vertical frame members 6a and 6b and a horizontal frame member 7 that is horizontally installed between the upper ends of the vertical frame members. One vertical frame member 6a is integrally provided with a fixed cam 8 extending from the vicinity of the center in the vertical direction to the vicinity of the lower end.

  The fixed cam 8 is curved toward the other vertical frame member 6b, that is, convex rightward in FIG. 1, and so that its tangential inclination changes over the entire length or partially from the upper end to the lower end. A fixed cam surface 9. Preferably, as shown in FIG. 2, a pair of fixed cams 8 and 8 and fixed cam surfaces 9 and 9 are provided symmetrically in the front and rear direction, one on each of the front and rear sides of the vertical frame member 6 a.

  In this embodiment, the movable support portion 3 includes upper and lower horizontal frame members 10a and 10b extending horizontally between the vertical frame members 6a and 6b of the fixed support portion 2, and vertical left and right vertical frame members 11a, 11b. The vertical frame members 11 a and 11 b are provided so as to be movable up and down along the guides 12 a and 12 b inside the vertical frame members 6 a and 6 b of the fixed support portion 2. Thereby, the movable support portion 3 is guided by the guide with the article A attached thereto, and is movable in the vertical direction with respect to the fixed support portion 2.

  The upper end 4a of the first spring 4 is fixed to the horizontal frame member 7 of the fixed support portion 2, and the lower end 4b is fixed to the horizontal frame member 10a of the upper side of the movable support portion 3, and expands and contracts in the vertical direction. An upward biasing force FA is generated. Due to the urging force FA of the first spring 4, the movable support portion 3 and the article A are supported so as to be displaceable in the vertical direction.

  Further, the movable support part 3 has a lower side frame member 10b as a movable cam that moves together with the movable support part in the front-rear direction and in a direction perpendicular to the moving direction of the movable support part, that is, in the horizontal direction. An extending cam groove 13 is provided. The cam groove 13 has a parallel upper downward first movable cam surface 14a and a downward upward second movable cam surface 14b facing each other.

  A cam follower member 15 is provided in the cam groove 13. The cam follower members 15 are respectively provided at the front and rear ends of a straight rod-shaped or circular tube-shaped first cam follower 16 penetrating the cam groove 13 in the front-rear direction and the first cam follower 16 projecting forward and backward from the cam groove. Roller-shaped second cam followers 17 and 17.

  The first cam follower 16 can move to the left and right along the cam groove 13 while contacting the first and / or second movable cam surfaces 14a and 14b on the outer peripheral surface thereof. The second cam follower 17 is preferably freely rotatable with respect to the both ends of the first cam follower 16 and is disposed so as to contact the fixed cam surface 9 of the corresponding fixed cam 8.

  A second spring 18 made of a compression coil spring is externally mounted on the lateral frame member 10b on the lower side of the movable support portion 3. The second spring 18 has an end 18a on the fixed cam 8 side fixed to the first cam follower 16, and an end 18b on the opposite side fixed to an appropriate position on the opposite side of the horizontal frame member 10b from the fixed cam 8. ing. The second spring 18 is provided so as to bias the cam follower member 15 in a state where the second cam follower 17 is constantly pressed against the fixed cam surface 9.

  At this time, the urging force FB of the second spring 18 generates a vertically upward or downward force with respect to the second cam follower 17 due to the inclination of the fixed cam surface 9 as described later. In addition, the second spring 18 is held straight in a compressed state without being buckled due to the presence of the horizontal frame member 10b.

  In this embodiment, the cam groove 13 extends from the vicinity of the end of the horizontal frame member 10b on the fixed cam 8 side toward the opposite side. As a result, the range in which the cam follower member 15 can move in the horizontal direction while bringing the second cam follower 17 into contact with the fixed cam surface 9, that is, the horizontal stroke can be set as large as possible. Therefore, the range in which the urging force FB of the second spring 18 can be used for pressing the fixed cam surface 9 by the second cam follower 17 can be made wider.

  When the article A is supported by the load support mechanism 1, the load W of the article A causes the first spring 4 to extend downward, and this force is transmitted via the movable support portion 3, and the cam groove 13 faces downward. The first follower member 15a acts to push down the cam follower member 15. On the other hand, the urging force FA of the first spring 4 is similarly transmitted through the movable support portion 3 and acts to push up the cam follower member 15 by the upward second movable cam surface 14b of the cam groove 13.

  By configuring as described above, as can be seen from FIG. 2, the first spring 4 and the second spring 18 at least partially overlap each other in a plane perpendicular to the moving direction of the movable support portion 3, that is, a horizontal plane. Can be arranged. With such an arrangement, when the load supporting mechanism 1 is realized in an actual device, the depth dimension can be designed to be smaller, that is, thinner. This is advantageous also when the load to be supported becomes large and a large urging force is required for the first spring 4 and / or the second spring 18 and the springs are enlarged.

  In another embodiment, a compression coil spring may be used for the first spring 4 instead of the tension coil spring, and the first support 4 may be disposed on the lower side so as to push up the movable support portion 3. In another embodiment, in addition to the first spring of FIG. 1, a compression coil spring can be added to push it up below the movable support 3. In either case, the depth dimension can be designed to be smaller when the device is actually implemented.

  In the present embodiment, as shown in FIG. 2, the fixed cam 8 and the second cam follower 17 are two symmetrical along the axial direction of the first cam follower 16, respectively, with the lower lateral frame member 10 b interposed therebetween. It is provided to make a pair. With such an arrangement, the force acting on the cam follower member 15 from the fixed cam 8 is distributed symmetrically in a well-balanced manner along the axial direction of the first cam follower 16, so that the first cam follower is less likely to bend or deform. It is. Due to the dispersion of the force, the burden of each fixed cam 8 is reduced, so that it can be made thinner. As a result, the entire apparatus can be reduced in thickness and weight.

  Furthermore, since the pressing force from each fixed cam 8 is concentrated on the contact position and acts in the same direction on the first cam follower 16, excessive bending or deformation is caused if the axial length is too long. There is a risk of breakage. In this embodiment, since there is no other component between the horizontal frame member 10b provided with the cam groove 13 and the fixed cam 8, the axial length of the first cam follower 16 can be shortened, which is advantageous. is there.

  In addition, the fixed cam surface 9 is divided into the following three regions in the range in contact with the second cam follower 17 depending on the position thereof. The first region S1 is a region in which the normal direction at the contact point with the second cam follower 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 second cam follower is substantially horizontal. In other words, in the second region S2, the tangential direction at the contact point with the second 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 where the normal direction at the contact point with the second cam follower is downward with respect to the horizontal direction.

  1 and 2, the movable support 3 on which the article A is placed is stationary at an upper position where the second cam follower 17 is in the first region S <b> 1 of the fixed cam surface 9. At this position, the displacement amount of the first spring 4 is small, and the magnitude of the spring force FA is smaller than the load W. FIG. 3 schematically shows an equilibrium state of forces acting on the system including the cam follower member 15, the movable support portion 3, and the fixed cam 8 in this stationary position.

  In order to simplify the description, the load on the movable support 3, the second spring 18 and the cam follower member 15, and the distance between the guides 12 a and 12 b of the fixed support 2 and the vertical frame members 11 a and 11 b of the movable support 3. Friction forces between the first cam follower 16 and the cam groove 13 and between the second cam follower 17 and the fixed cam 8 are omitted. Needless to say, these factors must be taken into account in actual design.

  At this time, when the load, that is, the weight of the movable support portion, the second spring, and the cam follower member is added to the force acting on the system including the cam follower member, the movable support portion, and the fixed cam, the resultant force is combined with the guide. If the frictional force generated between the vertical frame member, between the first cam follower and the cam groove, and between the second cam follower and the fixed cam spring is equal to or smaller than that, the equilibrium state is maintained. By these frictional forces, the movable support portion 3 can be held at the stationary position when it is stationary at a certain position in the equilibrium state.

  As the force for holding the movable support portion at the stationary position in this way, for example, when a torque limiter is provided between the first cam follower 16 and the second cam follower 17, the force acting between the two cam followers by the torque limiter is considered. It is done. Further, when the contact surface of the second cam follower 17 with the fixed cam surface 9 is made of a material having a large coefficient of friction such as rubber, the stationary position holding force is determined by the frictional force acting between the rubber surface and the fixed cam surface. Can also be obtained.

  Generally, the spring force F of a coil spring having a spring constant k is F with respect to the axial displacement x of the coil spring (displacement from the free length of the spring, that is, the length of the unloaded state: here positive in the compression direction). = K · x. In order to support the article A in a stationary state at the upper limit position of the movable support portion 3, the first spring 4 has already been extended upward in the vertical direction by a predetermined initial displacement amount xA0 from the free length. A force (FA0 = kA · xA0) is exerted, and at the same time, the second spring 18 is similarly compressed in advance by a predetermined initial displacement amount xB0 from the free length, and the initial spring force (FB0 = kB) is already upward in the vertical direction.・ Exhibiting xB0).

  In FIG. 3, between the first cam follower 16 and the cam groove 13, the load W of the article A from the first movable cam surface through the movable support portion 3 at the contact point Pa with the first movable cam surface 14a. It acts vertically downward with respect to the first cam follower. In this state, it is ideally assumed that the first cam follower 16 is in contact with the second movable cam surface 14b as well as the first movable cam surface so as to transmit force. it can. In that case, it is considered that the urging force FA of the first spring 4 acts vertically upward with respect to the first cam follower at those contact points Pb.

  Actually, it is difficult for the first cam follower 16 and the second movable cam surface 14b to come into contact with each other in such an ideal state so that the force can be transmitted. not exist. At this time, at the contact point Pa, a force Fv having a magnitude obtained by subtracting the urging force FA of the first spring 4 from the load W of the article A acts on the first cam follower 16 from the first movable cam surface 14a vertically downward. Is equivalent to In any case, a force Fv having a magnitude obtained by subtracting the biasing force FA of the first spring 4 from the load W of the article A acts on the first cam follower 16 from the cam groove 13 vertically downward. Will be.

  At the contact point Pc between the second cam follower 17 and the fixed cam surface 9, the pressing force from the second cam follower to the fixed cam surface and the reaction force Rc acting in the normal direction from the fixed cam surface are balanced. Yes. The pressing force from the second cam follower to the fixed cam surface is a resultant force of the urging force FB of the second spring 18 and the vertically downward force Fv acting on the first cam follower 16 as described above. The reaction force Rc of the fixed cam surface has an upward vertical component Rc1 and a horizontal component Rc2.

When the second cam follower is stationary at a certain position on the fixed cam surface, a force is applied between the load W, the spring force FA of the first spring 4 and the vertical component Rc1 of the reaction force Rc. The following relation always holds in theory, with the direction being vertical upward.
W + FA + 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.

Between the urging force FB of the second spring 18 and the horizontal component Rc2 of the reaction force Rc, the following relationship is always theoretically established with the force acting direction in the horizontal direction being positive in the right direction in the figure.
FB + Rc2 = 0
Accordingly, the magnitude of the horizontal component Rc2 of the reaction force Rc is equal to the urging force FB of the second spring 18. The magnitude of the reaction force Rc, and hence the magnitude of the vertical direction component Rc1, is determined by the magnitude of the urging force FB.

  In the case of FIG. 3, since the magnitude of the spring force FA of the first spring 4 is smaller than the load W, the vertical component Rc1 of the reaction force Rc acting upward from the fixed cam surface is applied as an assist force. The balance with the load W is realized in the vertical direction. When the movable support portion 3 is pushed down or pushed up in this state, the force is added to the load W or the spring force FA, and the balance is lost. Therefore, the article A can be easily raised and lowered with a relatively small force.

  When the movable support portion 3 is moved up and down, the cam follower member 15 moves downward or upward while being displaced in the left-right direction along the first cam follower 16 along the cam groove 13 and the second cam follower 17 along the fixed cam surface 9. To do. While the second cam follower is within the range of the first region S1 of the fixed cam surface, the upward vertical component Rc1 of the reaction force Rc helps to balance the spring force FA of the first spring 4 with the load W. To do.

  Within the range of the first region S1, when the movable support portion 3 is lowered and the displacement of the first spring 4 is increased, the spring force FA is correspondingly increased, and accordingly, due to the vertical component Rc1 of the reaction force Rc. The assist power can be reduced. Therefore, the inclination of the fixed cam surface 9 with respect to the vertical direction of the tangential direction also decreases as it approaches the second region S2 downward.

  On the other hand, as the second cam follower 17 moves downward on the fixed cam surface 9 due to the lowering of the movable support portion 3, the second spring 18 increases in compression displacement and the spring force FB increases. Accordingly, the pressing force from the second cam follower to the fixed cam surface, and thus the reaction force Rc, increases. The inclination of the fixed cam surface 9 is determined by the assist force due to the vertical component Rc1 of the reaction force Rc in consideration of the change of the spring force FB of the second spring 18 in addition to the change of the spring force FA of the first spring 4. It is preferable to determine so as to be optimal.

  4 shows that the movable support portion 3 on which the article A is placed is pushed down from the upper position in FIG. 1 so that the second cam follower 17 is in the second region S2 of the fixed cam surface 14 as indicated by an imaginary line in FIG. FIG. 4 schematically shows an equilibrium state of forces acting on the system including the cam follower member 15, the movable support portion 3, and the fixed cam 8 when stationary at an intermediate position. Similarly, for simplification, the load on the movable support 3, the second spring 18 and the cam follower member 15, and the distance between the guides 12a, 12b of the fixed support 2 and the vertical frame members 11a, 11b of the movable support 3, The frictional force between the 1 cam follower 16 and the cam groove 13 and between the second cam follower 17 and the fixed cam 8 will be omitted.

  In this case, between the first cam follower 16 and the cam groove 13, the spring force FA of the first spring 4 and the load W are substantially balanced in the vertical direction. Therefore, the spring force FA does not require an assist force due to the reaction force Rc from the fixed cam surface 9.

  At the contact point Pc between the second cam follower 17 and the fixed cam surface 9, the reaction force Rc from the fixed cam surface 14 is balanced with the urging force FB acting on the second cam follower from the second spring 18, and the vertical component Does not have. Even in this state, when the movable support portion 3 is pushed down or pushed up, the force is added to the load W or the spring force FA, and the balance is lost. Therefore, the article A can be easily raised and lowered with a relatively small force.

  The movable support portion 3 on which the article A is placed is further pushed down, and the second cam follower 17 is stopped at a lower position within the third region S3 of the fixed cam surface 9 as indicated by an imaginary line in FIG. At this time, the displacement of the first spring 4 further increases, and the magnitude of the spring force FA becomes larger than the load W.

  FIG. 5 schematically shows an equilibrium state of forces acting on the system including the cam follower member 15, the movable support portion 3, and the fixed cam 8 in this stationary position. Similarly, for simplification, the load on the movable support 3, the second spring 18 and the cam follower member 15, and the distance between the guides 12a, 12b of the fixed support 2 and the vertical frame members 11a, 11b of the movable support 3, The frictional force between the 1 cam follower 16 and the cam groove 13 and between the second cam follower 17 and the fixed cam 8 will be omitted.

  In the figure, between the first cam follower 16 and the cam groove 13, the urging force FA of the first spring 4 acts vertically upward with respect to the first cam follower at the contact Pb with the second movable cam surface 14b. ing. In this state, it is ideally assumed that the first cam follower 16 is in contact with the second movable cam surface 14a as well as the first movable cam surface 14a so as to transmit force. it can. In that case, it is considered that the load W of the article A acts vertically downward with respect to the first movable cam surface via the movable support portion 3 at the contact points Pa.

  Actually, it is difficult for the first cam follower 16 and the first movable cam surface 14a to come into contact with each other in such an ideal state so that the force can be transmitted. not exist. At this time, at the contact point Pb, a force Fv having a magnitude obtained by subtracting the load W of the article A from the biasing force FA of the first spring 4 acts on the first cam follower 16 from the second movable cam surface 14b vertically upward. Is equivalent to In any case, a force Fv having a magnitude obtained by subtracting the load W of the article A from the biasing force FA of the first spring 4 acts on the first cam follower 16 vertically upward from the cam groove 13. Will be.

  At the contact point Pc between the second cam follower 17 and the fixed cam surface 9, the pressing force from the second cam follower to the fixed cam surface and the reaction force Rc acting in the normal direction from the fixed cam surface are balanced. Yes. The pressing force from the second cam follower to the fixed cam surface is a resultant force of the urging force FB of the second spring 18 and the vertically upward force Fv acting on the first cam follower 16 as described above. The reaction force Rc of the fixed cam surface has a downward vertical component Rc1 and a horizontal component Rc2.

  At the lower position, since the magnitude of the spring force FA of the first spring 4 is larger than the load W, the vertical component Rc1 of the reaction force Rc acting downward from the fixed cam surface 9 is upward due to the spring force FA. By acting in the direction to reduce the urging force, that is, the pushing-up force, the balance with the load W is realized in the vertical direction. Even in this state, when the movable support portion 3 is pushed down or pushed up, the force is added to the load W or the spring force FA, and the balance is lost. Therefore, the article A can be easily raised and lowered with a relatively small force.

  When the movable support portion 3 is moved up and down, the cam follower member 15 moves downward or upward while being displaced in the left-right direction along the first cam follower 16 along the cam groove 13 and the second cam follower 17 along the fixed cam surface 9. To do. While the second cam follower is within the range of the third region S3 of the fixed cam surface, the downward vertical component Rc1 of the reaction force Rc reduces the push-up force due to the spring force FA of the first spring 4, and the load W Acts in a direction to balance with.

  Within the range of the third region S3, when the movable support part 3 is raised and the displacement of the first spring 4 is reduced, the spring force FA is correspondingly reduced, and accordingly, the pushing force due to the spring force FA is reduced. Therefore, the vertical component Rc1 of the reaction force Rc can be reduced. Therefore, the inclination of the fixed cam surface 9 with respect to the vertical direction of the tangential direction also decreases as it approaches the second region S2 upward.

  On the other hand, as the second cam follower 17 moves upward on the fixed cam surface 9 as the movable support portion 3 moves upward, the second spring 18 has a larger compression displacement and an increased spring force FB. Accordingly, the pressing force from the second cam follower to the fixed cam surface, and thus the reaction force Rc, increases. The inclination of the fixed cam surface 9 is optimal for reducing the push-up force by the spring force FA in consideration of the change of the spring force FB of the second spring 18 in addition to the change of the spring force FA of the first spring 4. Thus, it is preferable to determine.

  As described above, according to this embodiment, the load W of the article A acting on the system including the cam follower member 15, the movable support portion 3, and the fixed cam 8 and the spring force of the first spring 4 in the entire region of the fixed cam surface 9. FA, the spring force FB of the second spring 18 and the reaction force from the fixed cam 8 are balanced around the cam follower member 15. As a result, the movable support 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 easily raised and lowered with a relatively small force.

  The basic configuration of the present invention described above can be implemented with various modifications and changes. For example, the 2nd spring 18 can also comprise the horizontal frame member 10b with a tubular member, and can also be accommodated in it. Moreover, the movable support part 3 can have various structures other than the rectangular frame described above.

  Further, another set of the fixed cam 8, the cam groove 13, the cam follower member 15 and the second spring 18 of FIG. 1 is added and arranged in mirror symmetry with respect to the center lines in the left and right directions of the fixed support portion 2 and the movable support portion 3. be able to. At this time, it is preferable that the second spring is constituted by one common compression spring, and the cam follower members 15 are provided at both ends thereof. Thus, by constituting left-right symmetrically, the load which the fixed cam bears can be reduced, and as a whole, a larger load can be stably supported in a balanced manner in the left-right direction.

  A preferred embodiment of the article support device to which the modification of the present invention is specifically applied is shown in FIGS. The article support device 20 according to the present embodiment is for supporting a relatively large weight article B such as a large-screen TV monitor. The article support apparatus 20 includes a base 21 movably installed on a floor surface and the like. A fixed frame portion 22 fixed to a base, a support frame portion 23 attached to the fixed frame portion so as to be movable up and down, a first spring 24, and an operation handle portion 25 for operating the support frame portion 23 up and down. .

  The article B is integrally and detachably attached to the support frame portion 23 as will be described later. The lower portion of the fixed frame portion 22 is firmly fixed to the upper surface of the base plate 21a of the base 21 by a stay 21b.

  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. Further, the fixed frame portion 22 is provided with a first brake rail 31 extending in the middle between an intermediate frame 30 having a substantially intermediate height extending horizontally between the left and right side frames 28 and 29 and the upper frame. It has been.

  FIG. 9A shows a cross section of one side frame 28 of the fixed frame portion 22, but the other side frame 29 is also configured to be completely symmetrical with the side frame 28, so the drawing is omitted. To do. As shown in FIG. 9A, the side frames 28 and 29 have U-shaped guide rails 32 and 33 that open to the inside of the frame structure, respectively, from the substantially upper end to the lower end of the side frame. Is formed.

  Fixed cam members 34 and 35 are attached to the left and right side frames 28 and 29 of the fixed frame portion 22 symmetrically inside the lower portion of the intermediate frame 30. The fixed cam members 34 and 35 have two vertically long cam plates fixed in parallel to each other on the front and rear surfaces of the side frames 28 and 29, respectively. The fixed cam members 34 and 35 have fixed cam surfaces 36 and 37 extending from the vicinity of the upper end to the vicinity of the lower end, respectively. The fixed cam surfaces 36 and 37 are convex so as to face each other, and are provided so as to curve so that the inclination in the tangential direction changes over the entire length or partially from the upper end to the lower end.

  The support frame portion 23 has a substantially rectangular frame structure, and includes left and right guide frames 38 and 39 that extend vertically, an upper frame 40 that extends horizontally between the two guide frames, and two lower frames 41 that are slightly spaced apart from each other. , 42. The support frame portion 23 is fitted to the fixed frame portion 22 so that the left and right guide frames 38 and 39 are slidably fitted in the guide rails 32 and 33 of the corresponding left and right side frames 28 and 29 of the fixed frame portion, respectively. It is mounted so that it can move up and down along the guide rail.

  The left and right guide frames 38 and 39 are slidably brought into sliding contact with the inner surface of the guide rail in order to reduce or eliminate friction and other resistance that may occur between the inner surfaces of the guide rails 32 and 33. A plurality of moving rollers 43 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.

  By attaching the support frame portion 23 so that the outer frame is directly supported by the outer frame of the fixed frame portion 22 in this way, the structural strength of the support frame portion 23 itself and the entire apparatus is improved. Thereby, it is possible to realize the article support device 20 having a structure with a high load resistance and high strength that can cope with an increase in the weight of the article B.

  In order to fix the article B, the support frame portion 23 is provided with a pair of left and right mounting stays 44 that extend vertically in front of the guide frame. Further, the support frame portion 23 is provided with a brake device 45 in the center of the upper frame 40. The brake device can be engaged or disengaged by the operation handle portion 25 as will be described later.

  The first springs 24 have tension coil springs 46 and 47 that are arranged symmetrically and in parallel in the left-right direction, two each inside the right and left guide frames 38 and 39 of the support frame portion 23. The tension coil springs 46, 47 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 fixed to the lower frame 41 on the upper side of the support frame portion 23.

  As shown in FIG. 10, two cam grooves 48 and 49 penetrating the lower frame in the front-rear direction are provided on the lower frame 42 on the lower side of the support frame portion 23 in a bilaterally symmetrical manner. As shown in FIGS. 9A and 9B for the left cam groove 48, each cam groove 48, 49 extends horizontally from the left and right ends of the lower frame 42 toward the opposite side by a predetermined length. The first upper and lower movable movable cam surfaces 50a and 51a are parallel to each other, and the upper and lower second movable cam surfaces 50b and 51b are opposed to each other.

  A second spring 52 made of a compression coil spring is externally mounted on the lower frame 42. The second spring 52 can be surely prevented from buckling that may occur due to compression thereof, by covering the straight lower frame 42 constituting a part of the support frame portion 23 in this way. In another embodiment, the second spring 52 can be mounted inside the cylindrical lower frame 42.

  Cam follower members 55 and 56 are provided at left and right ends of the second spring 52 via cam follower holders 53 and 54 slidably inserted into the lower frame 42, respectively. As shown in FIG. 9A for the left cam follower member 55 in the figure, the cam follower members 55 and 56 are straight rod-shaped first cam followers 57 and 58 each having a circular cross section passing through the cam grooves 48 and 49 in the front-rear direction. Have Furthermore, the cam follower members 55 and 56 have roller-like second cam followers 59 and 60 provided at both front and rear ends of the first cam followers 57 and 58 protruding forward and backward from the cam groove.

  The first cam followers 57 and 58 move to the left and right along the cam grooves 48 and 49 while contacting the first movable cam surfaces 50a and 51a and the second movable cam surfaces 50b and 51b on the outer peripheral surfaces thereof. can do. The second cam followers 59 and 60 can be mounted so as to be rotatable with respect to the both ends of the first cam followers 57 and 58 via, for example, rolling bearings.

  The second cam followers 59 and 60 are disposed so as to contact the fixed cam surfaces 36 and 37 of the corresponding fixed cam members 34 and 35, respectively. The second cam followers 59 and 60 are urged outward in the horizontal direction by the second springs 52 and pressed against the corresponding fixed cam surfaces 36 and 37 of the fixed cam members 34 and 35, respectively.

  As shown in FIG. 9B, the cam follower holder 53 on the left side of the drawing is formed of an outer first holder member 61 and 62 and an inner second holder along the axial direction of the second spring 52. It consists of members 63 and 64. The first holder member rotatably holds the first cam followers 57 and 58 via a bearing, for example. The second holder member is a spring receiver for receiving the end of the second spring 52 at its end face.

  The first holder members 61 and 62 and the second holder members 63 and 64 are abutted with a plurality of steps that can be complementarily engaged in a stepped manner in the circumferential direction so as to be joined together to form a meshing joint. Each has a surface. The axial lengths of the cam follower holders 53 and 54 can be changed by relatively rotating the first holder members 61 and 62 and the second holder members 63 and 64 in the circumferential direction and changing their abutting positions. it can.

  As shown in FIG. 9A, each of the cam plates of the fixed cam member 34 is arranged so as to be symmetric in the front-rear direction along the axial direction of the cam follower member 55. The force that presses the cam follower member 55 is distributed along the axial direction and acts symmetrically in the longitudinal direction. Although not shown, the pressing force of each cam plate of the fixed cam member 35 is also distributed along the axial direction of the other cam follower member 56 and acts symmetrically in the longitudinal direction. Thereby, the cam follower members 55 and 56 are stably held horizontally in the cam grooves 48 and 49. Further, due to the dispersion of the force, the fixed cam member 35 can reduce the burden on each of the cam plates, so that they can be made thinner. As a result, the entire apparatus can be reduced in thickness and weight.

  Further, each cam plate of the fixed cam members 34, 35 has no other component between the lower frame 42 of the support frame portion 23 provided with the cam grooves 48, 49, so that they are arranged in the front-rear direction. The intervals can be reduced. As a result, the cam follower members 55, 56 can shorten the axial length of the first cam followers 57, 58, and eliminate in advance the risk of excessive bending, deformation, or breakage that may occur if they are too long. Can do.

  FIG. 11 is a partially enlarged view of the left side portion of the support frame portion 23 in plan view from above. As shown in the figure, the article support device 20 of this embodiment is arranged in a plane so that substantially the entire tension coil spring 46 of the first spring 24 overlaps the second spring 52 in the vertical direction. Although not shown, the tension coil spring 47 on the opposite side is also substantially planarly disposed so as to overlap the second spring 52 in the vertical direction. With such an arrangement, even when the outer diameter of the temporary first spring 24 and / or the second spring 52 is increased, the depth dimension of the article support device 20 can be minimized and designed to be thin.

  As shown in FIG. 8, the fixed cam surfaces 36 and 37 are divided into the following three regions according to the contact positions with the second cam followers 59 and 60, as described with reference to FIG. The first region S1 is a region in which the normal direction at the contact point with the second cam follower 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 second cam follower 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 where the normal direction at the contact point with the second cam follower is downward with respect to the horizontal direction.

  The operation handle portion 25 has left and right vertical transmission rods 65 attached to the front portions of the left and right guide frames 38 and 39 of the support frame portion 23. A substantially L-shaped connecting stay 66 is coupled to the lower portion of each transmission rod 65, and a long handle rod 67 extending in the left-right direction is held by the front ends of both connecting stays 66 protruding forward. Yes. The support frame portion 23 and the article B can be moved up and down by operating the operation handle portion 25 while holding the handle rod 67 by hand.

  8 and 12 show a case where the support frame portion 23 to which the article B is attached is at the uppermost position in the movement range. The second cam followers 59 and 60 are stationary at the upper ends of the first regions S1 of the fixed cam surfaces 36 and 37. In this position, the load W of the article B acting on the system comprising the cam follower members 55 and 56, the fixed frame portion 22 and the support frame portion 23, the spring force FA of the first spring 24, the spring force FB of the second spring 52, and The reaction force from the fixed cam surface is balanced around the cam follower member.

  In the first region S1, the displacements of the tension coil springs 46 and 47 of the first spring 24 are small, and the spring force FA is smaller than the load W of the article B. Since the reaction force Rc acting on the second cam follower 59 from the fixed cam surface 36 includes an upward vertical component, by adding this to the spring force FA of the first spring 24 as an assist force, the reaction force Rc is applied in the vertical direction. Equilibrium.

  13 and 14 show a case where the support frame portion 23 to which the article B is attached is at an intermediate position in the movement range. The second cam followers 59, 60 are stationary at positions within the second region S2 of the fixed cam surfaces 36, 37. Even at this intermediate position, the load W of the article B acting on the system consisting of the cam follower member, the fixed frame portion and the support frame portion, the spring force FA of the first spring, the spring force FB of the second spring, and the fixed The reaction force from the cam surface is balanced around the cam follower member.

  In the second region S2, the spring force FA of the first spring 24 and the load W are substantially balanced. The reaction force Rc from the fixed cam surfaces 36, 37 is substantially only a horizontal component, is balanced with the spring force FB of the second spring 52, and has no vertical component.

  15 and 16 show a case where the support frame portion 23 to which the article B is attached is at the lowest position in the movement range. The second cam followers 59, 60 are stationary at the lower end of the third region S3 of the fixed cam surfaces 36, 37. Even at this lower end position, the load W of the article B acting on the system consisting of the cam follower member, the fixed frame portion and the support frame portion, the spring force FA of the first spring, the spring force FB of the second spring, and the fixed The reaction force from the cam surface is balanced around the cam follower member.

  In the third region S3, the displacements of the tension coil springs 46 and 47 of the first spring 24 are large, and the spring force FA thereof is larger than the load W of the article B. The reaction force Rc acting on the second cam follower 59 from the fixed cam surface 36 includes a downward vertical component, which acts in a direction that reduces the push-up force due to the spring force FA of the first spring 24. The load W is balanced in the vertical direction.

  When the load W of the article B is reduced, the first spring 24 is not changed, so that the spring force FA is relatively increased. Therefore, in the first region S1, it is necessary to reduce the assist force to the spring force FA by the fixed cam surface, and in the third region S3, it is necessary to increase the downward force that reduces the push-up force due to the spring force FA.

  Conversely, when the load W of the article B is increased, the spring force FA of the first spring 24 is relatively decreased. Therefore, in the first region S1, it is necessary to increase the assist force to the spring force FA by the fixed cam surface, and in the third region S3, it is necessary to reduce the downward force that reduces the push-up force by the spring force FA.

  In the article support device 20, the biasing force of the second spring 52 at the same height position of the support frame portion 23 is adjusted by changing the axial length of the cam follower holders 53 and 54 to adjust the compression displacement of the second spring 52. The feedback force Rc from the fixed cam surface is adjusted to be increased or decreased. When the load W is small, the axial length of the cam follower holder is shortened to reduce the urging force FB of the second spring 52, thereby reducing the reaction force Rc from the fixed cam surface and its vertical component. Conversely, when the load W is large, the axial length of the cam follower holder is lengthened to increase the biasing force FB of the second spring 52, and the reaction force Rc from the fixed cam surface and its vertical component are Enlarge.

  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 portion 23 on which the article B is placed may collide with the fixed frame portion 22 violently in the moving range, that is, 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 based on the basic technical concept of the present invention, and a novel and innovative device is added to the cam plates of the fixed cam members 34 and 35 that follow the second cam followers 59 and 60. By adding, it is effectively realized.

  FIG. 17 is an enlarged view of the vicinity of the upper end of the fixed cam surface 36 of the left fixed cam member 34 in the drawing. In the same figure, the contact between the second cam follower 59 and the fixed cam surface 36 indicated by the solid line is effective for the fixed 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 the region S. An upper buffer region L1 and an upper stopper region M1 are continuously provided on the fixed cam surface 36 so as to extend further upward from the upper limit position C1.

  The upper buffer area L1 is greatly curved in the opposite direction to the virtual fixed cam surface extension 36 'indicated by an imaginary line in the drawing, and passes along a point D1 in which the tangential direction is directed in the vertical direction, and further, the upper stopper area M1 Is curving towards. The upper stopper area M1 is a downward horizontal surface that completely prevents the second cam follower 59 from moving upward.

  In the upper buffer area L1, the inclination in the tangential direction with respect to the vertical direction suddenly decreases from the upper limit position C1 to the point D1, and accordingly, the reaction force from the fixed cam surface 36 to the second cam follower 59 is an upward vertical component. Decreases rapidly and becomes zero at point D1. Thereby, the assist force from the fixed cam surface 36 to the urging force FA of the first spring 24 is suddenly lost, 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 area M1, the reaction force from the fixed cam surface 36 to the second cam follower 59 generates a downward vertical component. Thereby, since the force which pushes down the 2nd cam follower 59 acts, the raise of the article | item B and the support frame part 23 is further decelerated greatly.

  Thus, the downward decelerating action acts so that the guide frames 38 and 39 of the support frame portion 23 do not collide with the upper ends of the guide rails 31 of the fixed frame portion 22, so that the second cam follower 59 is in the upper buffer region L 1. Even if the motor stops at a stop or does not stop, it enters the upper stopper area M1 at a relatively low speed and stops. At this stop position, since the weight of the article B and the support frame portion 23 exceeds the pushing force of the first spring 24, after stopping for a very short time, the article B and the support frame portion 23 are slowly lowered slightly by their own weight. The two cam follower 59 returns to the vicinity of the upper limit position C1 and stops.

  FIG. 18 is an enlarged view of the vicinity of the lower end of the fixed cam surface 36. In the drawing, a contact point between the second cam follower 59 and the fixed cam surface 36 indicated by a solid line is a lower limit position C2 of the effective area S of the fixed cam surface. The fixed cam surface 36 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 fixed cam surface extension portion 36 "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 fixed cam surface 36 to the second cam follower 59 decreases in the downward vertical direction. The component rapidly decreases and becomes 0 at the point D2. As a result, the force that pushes down the support frame portion 23 against the urging force of the first spring 24 is suddenly lost, and the article B and the support frame portion are lost. The descent of is greatly decelerated.

  In the range beyond the point D2, conversely, the reaction force from the fixed cam surface 36 to the second cam follower 59 generates an upward vertical component. Thereby, since the force which pushes up the 2nd cam follower 59 acts, the fall of the article | item B and the support frame part 23 is further decelerated further.

  Thus, the upward decelerating action acts so that the guide frames 38 and 39 of the support frame portion 23 do not collide with the lower end of the guide rail 31 of the fixed frame portion 22, so that the second cam follower 59 is in the lower buffer region L 2. Stop at. At this stop position, the article B and the support frame portion 23 have their weights exceeding the push-up force of the first spring 24. Therefore, 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 first spring. Ascending, the second cam follower 59 returns to the vicinity of the lower limit position C2 of the fixed cam surface 36 and stops.

  17 and 18, only the left fixed cam member 34 in the figure has been described, but the right fixed cam member 35 may be similarly provided with an upper buffer area L1, an upper stopper area M1, and a lower buffer area L2. it can. Of course, you may provide only in one of the fixed cam members 34 and 35. FIG. Further, only one of the upper buffer area L1 and the upper stopper area M1 or the lower buffer area L2 can be provided.

  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 fixed cam surface 36 is extended above and below the effective area S, and the force acting around the cam follower member 55 Is provided with a buffer region where becomes non-equilibrium. In another embodiment, the region where the force around the cam follower member 55 is unbalanced in this way is between the region where the force around the cam follower member is balanced, ie, the range of the effective region S of the fixed cam surface 36. Can be provided inside.

  For example, in the first region S1 of the fixed cam surface 36, 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 fixed cam surface 36, 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, a user who operates the handle handle 67 of the operation handle portion 25 by hand can know the height position of the support frame portion 23 that is moving.

  Further, at the position where the direction of inclination changes in the non-equilibrium region, the force around the cam follower member 55 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.

  In the embodiment of FIGS. 1 and 6 described above, cam grooves 13, 48 and 49 are provided so as to extend the horizontal frame member 10b or the lower frame 42 horizontally. In another embodiment, depending on the structure and application of the support mechanism, design conditions, etc., the support mechanism may be provided obliquely, that is, in a crossing direction that is not orthogonal to the moving direction of the movable support portion or the support frame portion.

  Furthermore, the first movable cam surface and the second movable cam surface in the cam grooves 13, 48, 49 need not necessarily be provided in parallel. The first movable cam surface and the second movable cam surface are arranged to face each other, and one of the first movable cam surface and the cam follower member are in contact with each other, so that the load and the spring force of the first spring can be transmitted between them. It only has to be.

  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 45 of the support frame portion 23 and a first brake rail 31 of the fixed frame portion 22. The brake device 45 can be operated or released via the transmission rod 65 by operating the handle rod 67 of the operation handle portion 25.

  As shown in FIG. 19, the brake device 45 is disposed slightly in front of the upper frame 40 of the support frame portion 23 in parallel with and slightly behind the first brake rail 31 of the fixed support frame portion 22. The transmission plate 71 extends in the left-right direction. The transmission plate 71 is attached integrally with the left and right ends fixed to the upper ends of the left and right transmission rods 65 using, for example, an appropriate stay 72.

  The transmission rod 65 is attached to the left and right guide frames 38 and 39 of the adjacent support frame portion 23 so as to be movable within a slight predetermined range in the vertical direction. Specifically, the transmission rod 65 and the transmission plate 71 can be moved up and down between a home position shown in FIG. 20, an upward release position shown in FIG. 21, and a downward release position shown in FIG.

  At least one of the transmission rods 65 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 supported between the guide frames so as to be pivotable 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 65 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 65 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. 20, the return spring 76 has the other end 76b engaged with the locking portion, and urges the transmission rod 65 and the transmission plate 71 upward. When the transmission handle and the transmission plate are moved from the home position to the downward release position in FIG. 22 by pushing down the operation handle portion 25 by hand, the other end 76b of the return spring 76 is still engaged with the locking portion. Yes. Thereafter, when the hand is released from the operation handle portion, the transmission rod and the transmission plate are moved upward by the urging force of the return spring 76 and returned to the home position.

  Conversely, when the operation handle portion 25 is pushed up by hand and moved from the home position to the upward release position in FIG. 21, the other end 76b of the return spring 76 releases the engagement with the locking portion, and the return spring The urging power of 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 protruded forward from the transmission plate 71 with the first brake rail 31 interposed therebetween. The transmission pins 77a, 77b, 78a, 78b are disposed just outside the first brake rail 31 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 40 of the support frame portion 23 with the first brake rail 31 sandwiched therebetween and symmetrically on the left and right sides. 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 punched 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 portion 25 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 urged toward each other. The brake shoes are pressed against the side surface of the first brake rail 31 at the home position in FIG. 22 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 31 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 portion 25 is lifted and the transmission plate 71 is moved to the upward open position shown in FIG. 21, the upper transmission pins 77a and 78a abut against the side edges of the upper brake arms 81a and 82a, and this is connected to the tension spring 87a. , 87b 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 31 is released, so that the operation handle portion 25 can be lifted and the support frame portion 23 can be freely moved upward.

  Conversely, when the operation handle 25 is pulled down and the transmission plate 71 is moved to the downward open position shown in FIG. 22, the lower transmission pins 77b and 78b abut against the side edges of the lower brake arms 81b and 82b. This is rotated downward and outward 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 31 is released, so that the operation handle portion 25 can be pulled down as it is, 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 portion 25 with a strong force unexpectedly, the support frame portion 23 cannot be stopped at a desired position or by the buffer mechanism. There is a possibility of moving at such a high speed that a sufficient deceleration buffering 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. 23, the speed limiter mechanism 90 of this embodiment includes a centrifugal brake device 100 provided in the support frame portion 23 and a second brake rail 92 provided in the fixed frame portion 22. The second brake rail 92 is disposed on the rear side of the first brake rail 31 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 center plate 91 fixed to the center of the back surface of the upper frame 40 of the support frame portion 23 and the second brake rail 92. 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. 24 (a), a pair of brake arms 104a and 104b on one of the short sides of the rotating plate 102 is 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. Each of the brake arms 104a and 104b has a semicircular arc shape that curves along the inner peripheral surface of the circular frame 101, and is biased 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 operated, the brake shoes 106a and 106b do not come into contact with the inner peripheral surface of the circular frame 101 as shown in FIG. 24A, and when the centrifugal brake device is operated, 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. 23, 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. 24 (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 usable load range of the article support device 1 is set variously, and the fixed cam surface can be designed to have various cam profiles correspondingly. In addition to the above-described coil spring, the first and second springs are made of different shapes such as leaf springs and spiral springs, fluid springs such as air springs, elastic materials such as rubber, and other non-metallic materials. Various known springs can be applied.

DESCRIPTION OF SYMBOLS 1 Load support mechanism 2 Fixed support part 3 Movable support part 4 1st spring 5 Mounting stay 6a, 6b Vertical frame member 7 Horizontal frame member 8 Fixed cam 9 Fixed cam surface 10a, 10b Horizontal frame member 11a, 11b Vertical frame member 12a, 12b Guide 13 Cam groove 14a First movable cam surface 14b Second movable cam surface 15 Cam follower member 16 First cam follower 17 Second cam follower 18 Second spring 20 Article support device 21 Base 22 Fixed frame portion 23 Support frame portion 24 First Spring 25 Operation handle portion 26 Upper frame 27 Lower frame 28, 29 Side frame 30 Intermediate frame 31 First brake rail 32, 33 Guide rail 34, 35 Fixed cam members 36, 37 Fixed cam surfaces 38, 39 Guide frame 40 Upper frame 41, 42 Lower frame 45 Brake device 46, 47 Tension coil 48, 49 Cam grooves 50a, 51a First movable cam surfaces 50b, 51b Second movable cam surface 52 Second springs 53, 54 Cam follower holders 55, 56 Cam follower members 57, 58 First cam followers 59, 60 Second cam followers 71 Transmission Plates 81a, 81b, 82a, 82b Brake arms 83a, 83b, 84a, 84b Gear portions 85a, 85b, 86a, 86b Brake shoes 90 Speed limiter mechanism 91 Central plate 92 Second brake rail 100 Centrifugal brake device 101 Circular frame 102 Rotating plate 104a, 104b Brake arm 106a, 106b Brake shoe 107 Tension spring E Extension region L1 Upper buffer region L2 Lower buffer region M1 Upper stopper region N1, N2 Buffer region

Claims (8)

A fixed support;
A movable support for receiving a load that is movable in a predetermined range along a predetermined direction with respect to the fixed support;
A fixed cam provided on the fixed support portion and having a fixed cam surface;
A cam groove provided in the movable support portion, having a first movable cam surface and a second movable cam surface facing each other, and extending in a direction crossing a moving direction of the movable support portion;
A cam follower movable in the cam groove along the cam groove while being in contact with the first movable cam surface or the second movable cam surface;
A first spring interposed between the fixed support portion and the movable support portion so as to support the load;
A second spring provided on the movable support portion and biasing the cam follower toward the fixed cam surface;
The first movable cam surface is provided to transmit the load at a contact point with the cam follower;
The second movable cam surface is provided so as to transmit a biasing force of the first spring at a contact point with the cam follower,
The fixed cam surface, along the moving direction of the movable support, the reaction force against the cam follower, the Ingredient in a second direction perpendicular to the moving direction of at least the movable support portion at the contact point between the cam follower including uselessly , Curved in a convex shape toward the cam follower side,
The curvature of the fixed cam surface is caused by the load acting on the cam follower from the first movable cam surface , the biasing force of the first spring acting on the second movable cam surface, and the fixed cam surface against the cam follower. A reaction force and a biasing force of the second spring acting on the cam follower are balanced around the cam follower , and the movable support portion is designed to be stationary within the predetermined range. The load support mechanism. A plurality of support mechanisms each including the fixed support portion, the movable support portion, the first spring, the second spring, the cam follower, the fixed cam, and the cam groove;
The load support mechanism according to claim 1, wherein the plurality of support mechanisms share the fixed support portion and the movable support portion. Each of the fixed support portion, the movable support portion, the first spring, the second spring, the cam follower, the fixed cam, and the first support mechanism and the second support mechanism each including the cam groove,
The first support mechanism and the second support mechanism share the fixed support portion, the movable support portion, and the second spring, and are arranged symmetrically with respect to the moving direction of the movable support portion. The load supporting mechanism according to claim 1. The fixed cam surface has a first direction component along a moving direction of the movable support portion of a reaction force of the first fixed cam surface against the cam follower in the predetermined range in which the movable support portion is movable. A first region acting in the direction of the urging force of the first spring, and a component in the first direction along the moving direction of the movable support portion continuously from the first region, the urging force of the first spring 4. The load supporting mechanism according to claim 1, further comprising a second region acting in a direction opposite to the direction of. The movable support portion has a support member extending in a direction perpendicular to the moving direction;
The cam groove is provided in the support member;
5. The load according to claim 1, wherein the second spring is a compression coil spring that is externally or internally mounted on the support member and biases the cam follower in an extending direction of the support member. Support mechanism. The load support mechanism according to any one of claims 1 to 5, wherein the second spring has an adjustment mechanism for adjusting an urging force to the cam follower. It said cam follower comprises a first cam follower member extending through the cam groove in the longitudinal direction before Ki支 support member, a second of the cam groove longitudinal pair respectively provided front and rear ends of the first cam follower member protruding from Consisting of cam follower members,
The load support mechanism according to any one of claims 1 to 6 , wherein the fixed cam includes a pair of front and rear fixed cam members that abut each of the second cam follower members.   The first spring and the second spring are arranged so as to at least partially overlap each other when seen in a plan view in a direction perpendicular to the moving direction of the movable support portion. The load supporting mechanism according to any one of 1 to 7.

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