However, in the above-described prior art, in a state where the two-stage X-type frame structure is contracted (a state where the lifting platform is lowered), from the center pin contact of the lower X-type frame to the line of action of the horizontal force applied by the actuator Therefore, the moment around the central rotation axis of the lower X-shaped frame is small, and the horizontal force applied by the actuator cannot be fully utilized as the moment for rotating the diagonal member in the upright direction. For this reason, there has been a problem that a large driving force is required in the initial stage where the two-stage X-type frame structure shifts from the contracted state to the standing state. For this reason, the actuator as a drive source becomes large.
The present invention has been made in view of such problems, and the force from the actuator can be relatively small even in the initial stage when the two-stage X-type frame structure shifts from the contracted state to the standing state. It is an object of the present invention to provide an elevating device that can be made into an elevating device and an elevating bed having the same.
The lifting device according to the present invention includes a base, a lifting base, and a lifting part that lifts and lowers the lifting base with respect to the base. The lifting parts each include a first to a fourth pair. A first shaft that rotatably supports the first link on the base, and a first shaft that rotatably supports the second link on the base in a longitudinal direction. A rail, a second shaft that rotatably connects the first and second links, and an upper end portion of the first link and a lower end portion of the third link are rotatably connected to each other. A third shaft, a fourth shaft that connects the upper end of the second link and the lower end of the fourth link so as to be rotatable with each other, and the third and fourth links with each other. A fifth shaft that is rotatably connected, and a sixth shaft that rotatably connects an upper end portion of the third link to the lifting platform; A second rail that supports the upper end of the fourth link on the lifting platform so as to be movable in the longitudinal direction thereof, a cylinder portion is supported by the first link, and a piston portion is connected to the third link. An actuator, and changing the angle formed by the first link and the third link by the actuator to move the elevator up and down with respect to the base. It is characterized by making it.
The lifting device preferably further includes an elastic member that is provided between the third shaft and the base and urges the third shaft upward.
The first arm is fixed to the connecting rod fixed between the first links so as to protrude from the first link toward the first rail, and is fixed between the second links. The second arm is fixed to the connecting rod so as to protrude from the second link to the sixth shaft side, and the actuator is attached to the tips of the first and second arms. Preferably it is.
Moreover, the raising / lowering bed which concerns on this invention has the said raising / lowering apparatus.
In the lifting device of the present invention, the direction of force applied by the actuator is not a horizontal direction but an oblique direction, so that even when the two-stage X-type frame structure is most contracted, the actuator is applied from the central pin contact of the lower X-type frame. The distance to the line of action of the applied force is greater than when the actuator is installed in the horizontal direction, and the force from the actuator is relatively low even in the initial stage when the two-stage X-type frame structure shifts from the contracted state to the standing state It can be small.
Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. 1 (a) and 1 (b) are drawings showing an elevating bed having an elevating device according to an embodiment of the present invention, (a) is an overhead perspective view seen obliquely downward, and (b) is obliquely upward. FIG. 2A is a front view of the lifting device, and FIG. 2B is a side view. FIG. 3 is a perspective view showing an elevating part of the elevating device, and FIG. 4 is a perspective view showing a state where a cover of the elevating bed is removed. FIGS. 5A and 5B are front views showing links of the lifting mechanism, and FIGS. 6A to 6C are front views showing the operation of the lifting device.
The lifting bed according to the present embodiment is interposed between the base 1, the bed frame 3, and the base 1 and the bed frame 3, and moves the bed frame 3 up and down with respect to the base 1 by a link mechanism. It has the raising / lowering part 2, and the cover 4 of the raising / lowering part provided between the base 1 and the bed frame 3 so that the raising / lowering part 2 might be surrounded. A bed 35 is fixed to the bed frame 3.
The base 1 is configured such that height adjusting legs 12 are provided at the lower ends of the four corners of a frame composed of two sets of cross members 10 and vertical members 11. Further, between the longitudinal members 11, a rotating shaft 21 a that can rotate with respect to the longitudinal member 11, a rotating shaft 14 that can rotate with respect to the longitudinal member 11, and a rail 11 a provided on the inner surface of the longitudinal member 11 are supported. In addition, a movable shaft 21b movable along the rail 11a is stretched over. A control box 13 including a power source and a control circuit is attached between the longitudinal members 11.
In the elevating unit 2, a pair of links 22b whose lower ends are fixed to both ends of the rotating shaft 21a and a pair of links 22a whose lower ends are fixed to both ends of the moving shaft 21b are connected by pins 22c at the center. Each link is provided in an X shape so as to be rotatable with respect to each other. Further, the link 26a and the link 26b are rotatably connected with a pin 26c at the center thereof, and each link is provided in an X shape. The lower end of the link 26a is rotatably connected to the upper end of the link 22b by the rotary shaft 25c, and the lower end of the link 26b is rotatably connected to the upper end of the link 22a by the rotary shaft 25d. The link mechanism is provided. A reinforcing connecting rod 25a is stretched between the upper ends of the links 22b on the outer side of the rotating shaft 25c, and is fixed between the lower ends of the links 26b on the outer side of the rotating shaft 25d. A reinforcing connecting rod 25b is stretched over and fixed. The upper frame of this link mechanism is composed of a pair of vertical members 28 and horizontal members 29, and the upper end of the link 26a is rotatably connected to the vertical member 28 by a rotating shaft 27b, and the upper end of the link 26b. Is fixed to a rail 28a provided on the inner surface of the vertical member 28 so as to be movable and rotatable along the rail 28a. On the upper frame constituted by the vertical members 28 and the horizontal members 29, the bed frame 3 is installed. In the bed frame 3, between a pair of longitudinal members 31, a transverse member 30 at both ends of the longitudinal member, a transverse member 32 at the center of the longitudinal member, and two transverse members 33 between the transverse members 30, 32 are parallel to each other. And is fixed to the vertical member 31. Further, as will be described later, a stopper 50 is secured to the side surface of the cross member 29 of the upper frame to prevent the cover 4 from moving upside down when the bed is transported. A stay 34 for fixing the bed 35 is installed on the outer surface of the vertical member 31.
In the link mechanism configured as described above, the moving shaft 21b that spans between the lower ends of the link 22a and the moving shaft 27a that spans between the upper ends of the link 26b move along the rails 11a and 28a, respectively. By doing so, the crossing angle of each link is changed, and the bed frame can be moved up and down while the bed frame is held horizontally.
Thus, the mounting bracket 24b is fixed to the rotating shaft 14, and the mounting bracket 24a is also fixed to the rotating shaft 25c. The air spring 24 is installed between the mounting brackets 24a and 24b. ing. The air spring 24 provides an elastic force between the rotating shaft 14 and the rotating shaft 25c in a direction opposite to the direction in which both approach, so that the bed frame 3 is loaded by the load on the bed 35. It is designed not to inadvertently fall quickly. Further, the air spring 24 always lifts the rotary shaft 25c, thereby supporting the load of the bed 3 and reducing the driving force of the ascending operation by the actuator 23 described later.
A connecting shaft 21c is spanned and fixed between the lower portions of the pair of links 22b, and an arm 23b is fixed to the connecting shaft 21c. Further, a connecting shaft 25e is spanned and fixed between the lower portions of the pair of links 26a, and an arm 23a is fixed to the connecting shaft 25e by welding. The arm 23b projects from the link 22b to the right in FIGS. 5A and 5B, and the arm 23a projects from the link 26a to the upper side in FIGS. 5A and 5B. The cylinder portion of the actuator 23 is rotatably supported by the arm 23b, and the tip of the piston portion is rotatably connected to the arm 23a. When the actuator 23 operates and the piston part advances and retracts, the interval between the connecting shaft 21c and the connecting shaft 25e changes, and the angle formed by the link 26a and the link 22b changes. Can be driven to stretch or fold. Thereby, the bed 35 is driven up and down.
Next, the operation of the lifting device of this embodiment configured as described above will be described. In this link mechanism, the air spring 24 urges the rotary shaft 25c upward, so that a biasing force always acts on the link 22b in the standing direction so that the bed frame 3 opposes gravity. It is biased upward. Therefore, the driving force required for the actuator 23 is reduced by the air spring 24. Further, the air spring 24 prevents the bed frame 3 from inadvertently descending.
Then, as shown in FIG. 6 (a), when the actuator 23 is operated to advance the piston rod from the position where the bed 35 (bed frame 3) is lowered, the distance between the arm 23a and the arm 23b is increased. A force acts in the direction in which the angle is increased, and a force acts in a direction in which the angle formed by the link 26a and the link 22b increases. As a result, the link extends and the bed frame 3 rises as shown in FIGS. 6 (b) and 6 (c). Conversely, when the piston rod of the actuator 23 is retracted, the actuator 23 descends from the raised position shown in FIG. 6 (c) to the lower end position shown in FIGS. 6 (b) and 6 (a).
In this embodiment, the actuator 23 is provided between the arm 23b fixed to the link 22b and the arm 23a fixed to the link 26a, and a force is applied in a direction to directly expand the space between the link 22b and the link 26a. Therefore, the actuator 23 rises as shown in FIGS. 6A to 6C as the bed frame 3 rises. Further, even when the bed frame 3 is in the lower end position, as shown in FIG. 6A, the actuator 23 is not horizontal but is relatively upright. Therefore, when the bed frame 3 starts to rise, the actuator 23 From 23, a relatively upward force acts, that is, the actuator 23 exerts a force on the link mechanism in a direction close to the direction in which the bed frame 3 is to be raised, so that the driving force of the actuator 23 is efficiently Acts on the link mechanism. For this reason, the driving force of the actuator 23 is relatively small, and the actuator 23 can be downsized.
In particular, in the present embodiment, the position where the actuator 23 is attached is divided into the arm 23b protruding from the link 22b in the right direction of FIGS. Since the arm 23a projecting upward is used, the actuator 23 can be attached to the link mechanism in a further standing state as compared with the case where the actuator 23 is directly attached to the links 22b and 26a. For this reason, the driving force of the actuator 23 can be utilized for raising the bed frame 3 more efficiently.
DESCRIPTION OF SYMBOLS 1; Base 2; Elevating part 3; Bed frame 4; Elevating part cover 10: Cross member 11; Vertical member 13; Control box 14; Central part cross member 21a, 25c, 25d; Rotating shaft 22a, 22b; Pin 25a; connecting rod 23; actuator 24; air spring 34; stay 35;