JP3424733B2 - Lifter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lifter using a cross link mechanism, which is generally called a table lifter, and more particularly to an improvement of a drive mechanism for driving the cross link mechanism up and down.

[0002]

2. Description of the Related Art As a lifter of this type, a pair of left and right cross-link mechanisms that support an elevating and lowering platform so as to be able to move up and down in parallel are provided on a base, and drive means for driving the cross-link mechanism. Each of the cross links is provided with a driving member that is supported so as to be vertically swingable about a link intersection support shaft and is movable in a horizontal direction orthogonal to the link intersection support shaft. A lifter is known in which rollers that are fitted between the cross links of the mechanism and axially support rollers that drive the cross links are raised and lowered.

However, by moving the drive member in the drive means in the direction approaching the link intersection support shaft, the cross link is erected to raise the lifting platform, and conversely, the drive member is moved to the link intersection support shaft. On the other hand, by moving in the separating direction, the cross link can be caused to fall down by gravity and the lifting platform can be lowered.
A conventional lifter of this type, as disclosed in Japanese Patent Laid-Open No. 6-354394, has two rotary screw shafts arranged side by side in order to reciprocate the drive member in the horizontal direction orthogonal to the link intersection support shaft. Had been set up.

[0004]

In the conventional lifter having the above-described structure, the two rotary screw shafts, the two nut members screwed into the two rotary screw shafts, and the two rotary screw shafts are rotationally driven in the same direction. A large interlocking mechanism is required to make the manufacturing cost very high, and the driving member that pivotally supports the rollers for undulating the cross links of both cross link mechanisms at both ends is The two rotary screw shafts are respectively supported via nut members, and their postures are fixed in the horizontal direction and the vertical direction. Therefore, the dimensions of the entire device including both cross link mechanisms, the driving member, and the driving means thereof. If the accuracy is not sufficient, there is a drawback that an unreasonable bending force acts on each member including the rotary screw shaft, so that smooth operation cannot be expected and the useful life is shortened.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a lifter capable of solving the above-mentioned conventional problems, and the means are attached with the reference numerals of the embodiments described later. In other words, a pair of left and right cross link mechanisms 3A, 3 for supporting the lifting platform 2 on the base 1 so as to be able to move up and down in parallel.
B and a drive means 4 for driving the cross link mechanisms 3A, 3B. The drive means 4 is supported so as to be vertically swingable about link intersection support shafts 15, 16 of both cross link mechanisms 3A, 3B. The link intersection support shafts 15 and 16 are
Drive member 30 movable in a horizontal perspective direction orthogonal to
The drive member 30 includes each cross link mechanism 3
Rollers 41, 42, 4 which are fitted between the cross links 5, 6 of A, 3B to drive the cross links 5, 6 up and down.
4, 45 is a lifter pivotally supported, wherein the driving means 30 is provided on the driving member 30 at a central position between the pair of left and right cross link mechanisms 3A, 3B.
7 includes a rotary screw shaft 29 penetrating through the screw 7, and a motor 27 with a speed reducer that drives the rotary screw shaft 29 in forward and reverse directions. The nut member 47 is a vertical support shaft with respect to the drive member 30. 48,49 is swingably supported around the drive
Rollers 41, 42 , 4 pivotally supported by the moving member 30
One of the rollers 4 and 45 that contacts the link 12
2 is a grooved roller fitted to the link 12
It has been configured.

As the motor 27 with a speed reducer of the driving means 4, a motor having a cylindrical output shaft 35 which is externally fitted and locked to the shaft end 29a of the rotary screw shaft 29 is used. The motor 27 is provided with a torque arm 37 that engages with a member (shaft member 32) on the bearing 28 side that supports the rotary screw shaft 29 and stops the rotation of the motor 27 around the rotary screw shaft 29. You can

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. In FIGS. 1 to 4, 1 is a base, 2 is a lifting platform, and a base 1 is mounted on the base 1. It is supported by a pair of left and right cross link mechanisms 3A and 3B so as to be able to move up and down in parallel. Reference numeral 4 is a drive means for driving the cross link mechanisms 3A and 3B.

The cross link mechanisms 3A and 3B include cross links 5 and 6 and a pair of upper and lower slide guides 7, 8 and 9,
It is composed of 10 and. Each cross link 5,6
Two links 11, 12 and 13, each of the same length,
14 are overlapped with each other and pivoted in an X shape at left and right horizontal link intersection support shafts 15 and 16, and one end of one of the links 11 and 13 is horizontally and concentrically supported with respect to each other. A shaft 18 is pivotally supported on one end of the base 1 so as to be vertically swingable, and the other ends of the links 11 and 13 are connected by a single horizontally-supported connecting support shaft 19 and the connecting support shaft 19. Slide guide rollers 20 and 21 that fit into the front and rear horizontal guide grooves 7a and 9a of the slide guides 7 and 9 provided below one end of the hoisting and loading platform 2 are supported at both ends of. Also, the other link 1
One end of each of the links 2 and 14 is pivotally supported below the one end of the lifting platform 2 by the support shafts 22 and 23 that are horizontally oriented horizontally and concentric with each other. While being connected by one connecting support shaft 24 of
Slide guide rollers 25, 26 fitted in the front and rear horizontal guide grooves 8a, 10a of the slide guides 8, 10 provided on one end of the base 1 are supported at both ends of the connection support shaft 24. ing.

The driving means 4 is a motor 27 with a reduction gear,
It comprises a bearing 28, a rotary screw shaft 29, and a drive member 30. The bearing 28 rotatably supports one end of a front-rear horizontal rotation screw shaft 29, and the cross-link mechanisms 3A, 3A,
Two shaft members 31 and 32 having the link intersection support shafts 15 and 16 of the cross links 5 and 6 forming 3B at their outer ends are concentrically fixed and projected. Motor 27 with reduction gear
The reduction gear unit 33 is provided with a tubular output shaft 35 parallel to the motor unit 34, and the tubular output shaft 35 is externally fitted to the shaft end 29 a of the rotary screw shaft 29 protruding from the bearing 28. Then, the torque arm 37, which is keyed and attached to the speed reducer portion 33 via the bracket 36, is fitted to the one shaft member 32, so that the motor 27 with a speed reducer rotates around the rotary screw shaft 29. Has stopped.

The drive member 30 is formed by concentrically projecting shaft members 39 and 40 on both left and right sides of a rectangular frame portion 38, and the free end portion of one shaft member 39 has a cross link of the cross link mechanism 3A. 5, the roller 41 abutting on the lower cam surface 11a of the link 11 and the upper cam surface 12 of the link 12
The roller 42 that is in contact with a is pivotally supported by the left and right horizontal common support shaft 43, and the free end portion of the other shaft member 40 has the link 1 in the cross link 6 of the cross link mechanism 3B.
A roller 44 that abuts on the lower cam surface 13a of the link 3 and a roller 45 that abuts on the upper cam surface 14a of the link 14 are pivotally supported by a common horizontal support shaft 46.

Further, as shown in FIGS. 5 and 6, a nut member 47 screwed onto the rotary screw shaft 29 is provided in the rectangular frame portion 38 of the drive member 30, and a pair of upper and lower concentric vertical support shafts are provided. It is horizontally rotatably supported by 48 and 49. Fifty
Is an annular bearing member which is externally fitted and fixed to the nut member 47, and is fixed inwardly from both upper and lower sides of the rectangular frame portion 38 to shaft holes provided concentrically on the upper and lower sides of the annular bearing member 50. The provided vertical support shafts 48 and 49 are fitted together.

With the above structure, the drive means 4 can swing up and down about the concentric link intersection support shafts 15 and 16 of the cross links 5 and 6 in both cross link mechanisms 3A and 3B, and the drive member 30 , Which is swingable in the vertical direction around the rotary screw shaft 29 and has a concentric vertical support shaft 48,
It can swing horizontally around 49. Therefore, the cam surfaces 11a to 1 of the links 11 to 14 to which the rollers 41, 42, 44, and 45 on both ends of the drive member 30 correspond, respectively.
Of these rollers 41, 42, 44, 45, only one roller 42 is a grooved roller with which the upper side of the link 12 fits so that it does not come off in the horizontal direction from the left and right.

According to the above construction, however, the driving means 4
The nut member 47 that is driven by the motor 27 with a speed reducer to drive the rotary screw shaft 29 in the normal direction to be screwed into the rotary screw shaft 29.
The driving member 30 is moved so as to be drawn toward the link intersection supporting shafts 15 and 16 side through the driving member 30.
The rollers 41, 42, 44, and 45 at both ends of the above will push open so as to erect the cross links 5 and 6 via the cam surfaces 11a to 14a of the corresponding links 11 to 14, respectively. Therefore, the cross links 5 and 6 of both cross link mechanisms 3A and 3B are moved in the forward and backward directions within the slide guides 7 to 10 of the slide guide rollers 20, 21, 25 and 26 of the links 11 to 14, respectively. The lying posture shown in FIG. 1 is changed to the standing posture shown in FIG. 2, and the lifting platform 2 is lifted by the both cross links 5 and 6.

Further, from the state in which the lifting platform 2 is in the raised position, the motor 27 with a speed reducer of the driving means 4 is operated to drive the rotary screw shaft 29 in the reverse direction, and the nut member 47 screwed into the rotary screw shaft 29. By moving the drive member 30 in the direction away from the link intersection support shafts 15 and 16 via
Each roller 41, 42, 44, 4 at both ends of the drive member 30
5 moves in a direction that allows the cross links 5 and 6 to fall over. Therefore, the load acting on the hoisting platform 2 causes the hoisting platform 2 to change the cross links 5 and 6 from the standing posture shown in FIG. 2 to the lying posture shown in FIG. 1 as the drive member 30 moves. While descending.

[0015]

As described above, according to the lifter of the present invention, the lifter is provided with the rollers which are fitted between the cross links of the pair of left and right cross link mechanisms for supporting the lift platform so as to lift and lower the cross links. The drive member is moved in a horizontal perspective direction orthogonal to the link intersection support shaft by one rotary screw shaft, and the drive member side nut member through which the rotary screw shaft is threaded is By supporting the drive member so as to be swingable about a vertical support shaft, the drive member is swingable in a vertical direction about one rotation screw shaft, and at the same time, is supported by the vertical support shaft. It becomes possible to swing horizontally around it.

That is, the driving member has a vertical degree of freedom of rotation and a horizontal degree of freedom of rotation about one rotary screw shaft, and the manufacturing dimensional accuracy of each part including the cross link of the cross link mechanism is somewhat poor. In addition, without applying unreasonable bending force to each part such as the rotary screw shaft, the rollers at both ends of the drive member can be surely brought into contact with each link of both cross links to smoothly drive both cross links up and down. it can. In other words, as compared with the conventional structure using two rotary screw shafts, the structure of the drive means is extremely simple and not only can the weight be reduced, but the manufacturing is also very easy. Moreover, it became possible to obtain a lifter having a long service life. Further according to the invention, as described above
Although it is a driving member with a large degree of freedom,
Align the rollers on both ends of the drive member with the specified number of links
Surely abut the place to smoothly drive the undulation of the cross link.
And it can be done reliably.

According to the second aspect of the present invention, the coupling between the rotary screw shaft and the output shaft of the motor with reduction gear is not required, and the mount for mounting the motor with reduction gear is rotated. Since it is not necessary to provide it on the bearing side member of the screw shaft, the structure becomes simpler and the cost can be further reduced.

[0018]

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view in a state where a lifting platform is lowered.

FIG. 2 is a vertical cross-sectional side view in a state where the lifting platform is raised.

FIG. 3 is a cross-sectional plan view in the state of FIG.

FIG. 4 is a vertical cross-sectional rear view in the state of FIG.

FIG. 5 is a partially cutaway plan view showing a support structure of a drive member with respect to a rotary screw shaft.

6 is a vertical side view of FIG.

[Explanation of symbols]

1 Base 2 Lifting / unloading platform 3A, 3B Cross link mechanism 4 Drive means 5, 6 Cross link 7-10 Slide guide 11-14 Link 15, 16 Link intersection support shaft 20-21, 25, 26 Slide guide roller 27 With reduction gear Motor 28 Bearing 29 Rotating spiral shaft 29a Shaft end portion of rotating spiral shaft 30 Driving member 35 Cylindrical output shaft of motor with reduction gear 37 Torque arms 41, 42, 45, 46 Cross link undulation driving roller 47 Nut members 48, 49 Vertical spindle

Claims (2)

(57) [Claims] 1. A pair of left and right cross-link mechanisms for supporting an elevating and lowering platform in parallel with each other on a base, and a drive means for driving the cross-link mechanism, the drive means being links of both cross-link mechanisms. A drive member that is swingably supported about an intersection support shaft and is movable in a horizontal perspective direction orthogonal to the link intersection support shaft is provided between the cross links of each cross link mechanism. A rotary screw shaft that axially supports a roller that fits in and drives the cross link up and down, wherein the drive means includes a single rotary screw shaft that threadably penetrates a nut member provided in the drive member. And a motor with a speed reducer that drives the rotary screw shaft to rotate forward and backward, wherein the nut member is rotatably supported on the drive member around a vertical support shaft and is axially supported by the drive member. Roller of
Among them, only the roller that abuts one link is
Lifter that is a grooved roller that fits in the slot. 2. A motor with a speed reducer of the drive means, wherein a cylindrical output shaft is externally fitted and locked to a shaft end portion of the rotary screw shaft, and a member on a bearing side which supports the rotary screw shaft. The lifter according to claim 1, comprising a torque arm that engages to stop rotation about the rotary screw axis.