JP2820669B2 - Electric table lift device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Panta arm having two arms connected in an X-shape between a table and a base. The present invention relates to an electric table lift device that moves a table up and down in parallel.

[0002]

2. Description of the Related Art Heretofore, the present applicant has made various improvements regarding this type of table lift apparatus as disclosed in Japanese Patent Application No. 7-25388. One example of this conventional electric table lift device is shown in FIG. 4 with reference to FIG. 1 of the same application.

As shown in the figure, a conventional electric table lift device (hereinafter, also simply referred to as “lift device”) 1 has an outer arm 5 and an inner arm 6 connected between a table 2 and a base 3. A table lift device that interposes a panta arm 4 connected in an X-shape via a, and moves the table 2 up and down in parallel by expanding and contracting the panta arm 4, comprising an outer arm 5 and an inner arm 6. Between
One end is rotatably connected to the inner arm 6 via a fixed fulcrum 9a, and the other end is connected to the outer arm 5 via a guide roller 13 so as to be rotatable and movable along the arm longitudinal direction. When the moving fulcrum 12 is displaced toward the connecting fulcrum 7 of the outer arm 5, the intermediate arm 9 is interposed in such a manner that the punter arm 4 extends, and the movable fulcrum 12 of the intermediate arm 9 is connected to the outer arm 5. And the other end of the intermediate arm 9 is displaced toward the center in the longitudinal direction of the arm when the electric cylinder 10 is actuated to the nut pulling side. Electric cylinder 10 for the entire range of vertical movement
As a result, the lift device 1 can be made more compact by using a smaller electric cylinder 10.

[0004]

However, there is still a point to be improved in the conventional electric table lift apparatus 1 as well. That is, in the conventional table lift device 1, since the intermediate arm 9 is set on only one side with respect to the connection fulcrum 7, the rigidity of the device becomes uneven right and left, and as a result, the table 2 sinks when a load is loaded. There was a problem that it was large.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a table lift device in which the rigidity of the entire device is increased and the table sinks less.

[0006]

According to a first aspect of the present invention, there is provided a table lift apparatus including a panter arm formed by connecting an outer arm and an inner arm in an X-shape between a table and a base. An electric table lift device for moving the table up and down by expanding and contracting the pant arm using an electric cylinder as a drive source, one end of which is rotatably supported by one of the outer arm or the inner arm, and the other end. An intermediate arm slidably contacting the edge of the other arm is disposed on the left and right sides with respect to the connection fulcrum of the panta arm, and a screw shaft of the electric cylinder is connected to the other end of one intermediate arm, A nut for the electric cylinder is connected to the other end of the other intermediate arm, and the operation of the electric cylinder causes the other ends of the two intermediate arms to approach and move away from each other to expand and contract the panta arm. Characterized in that it was.

[0007] According to this table lift device, when the motor of the electric cylinder rotates forward, the nut and the screw shaft move in the direction approaching each other (pull side of the nut), and the other end of one intermediate arm and the other end of the intermediate arm. The other ends of the intermediate arms approach each other, whereby both intermediate arms pivot in the vertical direction, respectively, and the punter arms extend, thus raising the table.

On the other hand, when the motor of the electric cylinder rotates in the reverse direction, the nut and the screw shaft move in a direction away from each other,
The other end of one intermediate arm and the other end of the other intermediate arm are spaced apart from each other, whereby both intermediate arms pivot sideways, respectively, and the punter arm shrinks, thus lowering the table.

As described above, since the intermediate arms are arranged on the left and right sides of the fulcrum of the connection of the panta arm, the rigidity of the panta arm is increased, and the table does not sink much as in the conventional case.

Further, since the nut and the screw shaft which are meshed with each other are moved in the direction of approaching and separating from each other, and the punter arm expands and contracts, only one side of the nut or the screw shaft as in the prior art is provided. The stroke of the electric cylinder is doubled as compared with the configuration in which the pantator arm is extended and contracted by the movement. As a result, the thrust required for the screw shaft of the electric cylinder is half that of the conventional thrust, so that the diameter can be reduced.

According to a second aspect of the present invention, there is provided the table lift apparatus according to the first aspect, wherein the movable fulcrum and the fixed fulcrum of the outer arm and the inner arm of the panta arm are vertically symmetric and left-right symmetric with respect to the connection fulcrum. And the table is moved up and down while holding the axis of the screw shaft of the electric cylinder crossing the axis of the connection fulcrum.

According to this table lift device, even if the table moves up and down (regardless of the position of the table), the axis of the screw shaft is always maintained in a state of intersecting with the connection fulcrum. Direction load is not added, thereby without impairing the durability of the table lift device,
For example, the diameter of the connecting pin as the connecting fulcrum can be made smaller.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 1 shows the table lift device 20 of the present embodiment, in which the table 21 is raised, and FIG. 3 shows a state in which the table 21 is lowered almost to the lower end position.

The table lift device 20 of the present embodiment
As shown in FIG. 2, two sets of panta arms 23 are provided between the table 21 and the base 22,
The table 21 is moved up and down in parallel by making the electric cylinder 40 extend and contract the members 3 and 23.

Each of the two punter arms 23 and 23 has an outer arm 25 and an inner arm 26 rotatably connected to each other via a connecting fulcrum 27.
One end (the left end in the figure) of each of the bases 5 and 25 is rotatably supported at the left corner of the base 22 via a fixed fulcrum 25a. On the other hand, rollers 25b are rotatably attached to the other ends (right ends in the figure) of the outer arms 25, 25, respectively, and the rollers 25b, 25b are respectively slidably in contact with the lower surface on the right side of the table 21. Have been. The center of rotation of the roller 25b corresponds to the fulcrum of movement of the outer arm 25 (hereinafter denoted by reference numeral 25b).

One end (left end in the figure) of each of the inner arms 26, 26 is rotatably supported on the lower surface of the left corner of the table 21 via a fixed fulcrum 26a.
On the other hand, rollers 26b are also rotatably mounted on the other ends (right ends in FIG. 1) of the inner arms 26, 26, and the rollers 26b, 26b are slidably contacted with the upper surface on the right side of the base 22 in a rolling manner. Have been. The center of rotation of the roller 26b corresponds to the fulcrum of movement of the inner arm 26 (hereinafter denoted by reference numeral 26b).

The connecting fulcrum 27 is set between the fixed fulcrum 25a and the movable fulcrum 25b and between the fixed fulcrum 26a and the movable fulcrum 26b.
a, 25b, 26a and 26b are connected fulcrums 27, respectively.
Symmetrical and vertically symmetrical with respect to.

Also, as shown in FIG.
The moving fulcrums 25b, 25b of 5, 25 are coaxially connected by a rod 25c, and the moving fulcrums 26b, 26b of both inner arms 26, 26 are also coaxially connected by a rod 26c. It is designed to expand and contract as one.

Next, the right intermediate arm 30 and the left intermediate arm 31 are respectively fixed to the two inner arms 26, 26 at positions symmetrical with respect to the connecting fulcrum 27, respectively.
It is rotatably supported via 31a.

As shown in FIG. 2, both left intermediate arms 31, 3
1 are connected via a connecting rod 32 having a rectangular cross section, and the front ends of both right intermediate arms 30 are connected via a connecting block 33. At both ends of the connecting rod 32, support shafts 32a, 32a having a circular cross section are provided coaxially with each other. The two support shafts 32a, 32a are rotatably inserted into the distal end of the left intermediate arm 31, and protrude laterally from the distal end. Guide rollers 31b are rotatably mounted on the protruding portions. Have been. Hereinafter, the center of rotation of the guide roller 31b, that is, the axis of the support shaft portion 32a is also referred to as a movement fulcrum 32a of the left intermediate arm 31.

On the other hand, support shafts 33a, 33a having a circular cross section are provided coaxially with each other at both ends of the connection block 33. The two support shafts 33a, 33a are rotatably inserted into the distal end of the right intermediate arm 30 and protrude laterally from the distal end. Guide rollers 30b are rotatably mounted on the protruding portions. Have been. Hereinafter, the center of rotation of the guide roller 30b, that is, the axis of the support shaft portion 33a is defined as the movement fulcrum 33a of the right intermediate arm 30.
Also called.

As shown in FIGS. 1 and 3, the right intermediate arm 30 is disposed so as to rise upward from the fixed fulcrum 30a so that the guide roller 30b can slide along the lower edge of the outer arm 25. Has been abutted. On the other hand, the left intermediate arm 31 is disposed so as to fall downward from the fixed fulcrum 31a, and slidably abuts the guide roller 31b along the upper edge of the outer arm 25. Therefore, the right intermediate arm 30 rotates upward (counterclockwise) about the fixed fulcrum 30a, and the left intermediate arm 31 rotates downward (counterclockwise) about the fixed fulcrum 31a. Then, the panta arm 23 extends upward and the table 21 rises. At this time, the movement fulcrum 33a of the right middle arm 30 moves toward the connecting fulcrum 27 along the lower end edge of the outer arm 25, and the movement fulcrum 3 of the left middle arm 31 moves.
2a moves toward the connection fulcrum 27 side along the upper edge of the outer arm 25.

Conversely, when the two intermediate arms 30 and 31 rotate clockwise, the panta arm 23 is allowed to contract downward, and the table 21 is lowered. At this time, the movable fulcrum 30a moves toward the movable fulcrum 25b along the lower edge of the outer arm 25, and the movable fulcrum 32a moves toward the fixed fulcrum 25a along the upper edge of the outer arm 25.

The two intermediate arms 30, 31 rotate counterclockwise as the distance between the connecting block 33 and the connecting rod 32 decreases, and rotate clockwise as the distance increases. . Change in the distance between the connecting block 33 and the connecting rod 32, that is, the rotation of the intermediate arms 30, 31 and, consequently, the panta arm 2
The expansion and contraction of 3, 23 is performed using the electric cylinder 40 as a drive source.

In this embodiment, the electric cylinder 40 is
An electric motor 41 and two sets of ball screws 42 are provided. In general, an electric cylinder has an electric motor and one or more sets of ball screws, and has a configuration in which rotational motion of the electric motor is transmitted to the ball screw and converted into linear motion.

The electric motor 41 is attached to the connection block 33. A double-type drive sprocket 43 is attached to the output shaft of the electric motor 41.

On both sides of the driving sprocket 43, driven sprockets 44, 44 each having a substantially cylindrical shape are arranged. Each of the driven sprockets 44, 44 has a bearing 4
It is rotatably supported by the connection block 33 via the connecting members 5 and 45. A chain 46 is extended between the driven sprockets 44 and the driving sprocket 43. Therefore, when the electric motor 41 starts,
The driven sprockets 44, 44 rotate in the same direction via the drive sprocket 43 and the chain 46.

The nuts 42a of the ball screws 42 are fixed to the driven sprockets 44, 44. Therefore, when the electric motor 41 is started, the nuts 42a, 42a are used.
Rotate in the same direction.

The rear ends (the left ends in the figure) of the screw shafts 42b, 42b in which the two nuts 42a, 42a are engaged are non-rotatably attached to the connecting rod 32, respectively. The tip ends of both screw shafts 42b, 42b are inserted through the inner peripheral side of the driven sprocket 44, respectively.

Here, as shown in FIGS. 1 and 2, the lengths of the two intermediate arms 30, 31 are set so that the moving fulcrums 33a, 32a of the left and right intermediate arms 30, 31 and the connecting fulcrum 27 are always aligned. The distance between the fixed fulcrum 30a and the movable fulcrum 33a and the distance between the fixed fulcrum 31a and the movable fulcrum 32a) are set to the same size, and the connection fulcrum 27 and the fixed fulcrum 30 are
a, the distance between the connecting fulcrum 27 and the fixed fulcrum 31a are set to the same size, and the upper and lower edges of the outer arm 25 are formed point-symmetrically.

The two screw shafts 42b, 42b are connected to the moving fulcrums 33a, 32a of the left and right intermediate arms 30, 31 and the connecting fulcrum 2a.
7, so that both screw shafts 42b, 42b are always maintained at a position intersecting the axis of the connection fulcrum 27 regardless of the position of the table 21.

According to the table lift device of the present embodiment configured as described above, the driven sprocket 4 is driven by the electric motor 41 being activated in the normal rotation direction (table ascending direction).
When the nuts 4 and 44 rotate, the nuts 42a and 42a rotate to the left in FIG. 2 through the engagement with the screw shafts 42b and 42b, and thus the connecting block 33 moves to the left in the drawing.

On the other hand, when the nuts 42a, 42a rotate, the screw shafts 42b, 42b move rightward in the figure, so that the connecting rod 32 moves rightward in the figure in conjunction with the movement of the connecting block 33 leftward in the figure. Move the same distance. When the electric motor 41 is started in the normal rotation direction in this way, the connection block 33 and the connection rod 32 move in a direction approaching each other, and the interval between the two decreases.

When the connecting block 33 and the connecting rod 32 move in a direction approaching each other, the right intermediate arm 30 and the left intermediate arm 31 rotate counterclockwise as described above, and accordingly, the panta arms 23, 23 Extend and the table 21 rises.

As the table 21 rises, the guide rollers 30b and 31b of the intermediate arms 30 and 31 are rolled along the lower and upper edges of the outer arm 25, respectively, so that the weight of the table 21 and the load is reduced. It is also received symmetrically by the two intermediate arms 30, 31.

On the other hand, when the electric motor 41 is rotated in the reverse direction, the nuts 42a, 42a rotate in the opposite direction, so that the connecting block 33 moves rightward in the drawing, and the connecting rod 32 moves the same distance leftward in the drawing. Therefore, the two move in the direction away from each other, and the space between them increases.

When the connecting block 33 and the connecting rod 32 move away from each other, the two intermediate arms 3 are moved.
Since both 0 and 31 rotate clockwise, the reduction of the panta arms 23 and 23 is allowed, and as a result
The table 21 is lowered by the weight of the load.

In the course of lowering the table 21, the guide rollers 30b, 31b of the intermediate arms 30, 31 move toward the fixed fulcrum 25a or the movable fulcrum 25b while sliding on the upper and lower edges of the outer arm 25. Therefore, the weight of the table 21 and the load is reduced by the two intermediate arms 30 and 3.
1 allows the image to be received equally on the left and right.

As described above, according to the table lift device of the present embodiment, the connection fulcrum 27 of the panta arm 23 is
Since the intermediate arms 30 and 31 are arranged on both sides, the rigidity of the panta arm 23 is increased, and as a result, sinking of the table 21 when a heavy object is placed can be reduced.

Since the two intermediate arms 30 and 31 are arranged symmetrically in the left and right directions, the weight of the table 21 and the load can be equally received on the left and right sides.

Further, the nut 42a and the screw shaft 42b, which are meshed with each other, move in the direction of approaching and moving away from each other, so that the punter arm 23 expands and contracts. Compared to a configuration in which the panta arm is expanded and contracted by moving only one side, the electric cylinder 4
The stroke of 0 is amplified twice, and as a result, the thrust required for the screw shaft 42b of the electric cylinder 40 is half that of the conventional one, so that the diameter can be reduced.

The panta arm 23 is vertically symmetrical and symmetrical with respect to the connection fulcrum 27, and the screw shaft 42b of the electric cylinder 40 is always kept crossing the axis of the connection fulcrum 27. According to this, since the thrust for expanding and contracting the panta arm 23 generated by the rotation of the two intermediate arms 30 and 31 is equally applied to the left and right, no radial external force is applied to the connection fulcrum 27, At this point, the diameter of the pin constituting the connection fulcrum 27 can be reduced.

Various modifications can be made to the embodiment described above. For example, the electric cylinder 40 has been exemplified by a configuration including two sets of ball screws 42, 42, but an electric cylinder having one set of ball screws may be used as a drive source.

Further, the intermediate arms 30 and 31 have been exemplified by a configuration supported by the inner arm 26, but one of the intermediate arms 30 and 31 is supported by the inner arm 26 and the other is supported by the outer arm 25.
The configuration may be such that the panta arm 23 is extended or contracted by the two rotating in opposite directions.

[Brief description of the drawings]

FIG. 1 is a front view of a table lift device according to an embodiment of the present invention in a state where a table is raised. This figure is a view as seen in the direction of the arrow along the line AA in FIG. 2, and therefore, the inner arm is seen toward the near side.

FIG. 2 is a plan view of the table lift device. Table is omitted in this figure

FIG. 3 is a front view of the table lift device in a state where the table is lowered.

FIG. 4 is a front view of a conventional table lift device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Conventional table lift device 9 ... Intermediate arm 10 ... Electric cylinder 20 ... Table lift device 21 ... Table, 22 ... Base 23 ... Panta arm 25 ... Outer arm 26 ... Inner arm 27 ... Connection fulcrum 30 ... Right intermediate arm 31 … Left middle arm 40… Electric cylinder 42a… Nut, 42b… Screw shaft

Claims (2)

(57) [Claims] 1. A table comprising: a panta arm comprising an outer arm and an inner arm connected in an X-shape between a table and a base; An electric table lift device for raising and lowering, an intermediate arm having one end rotatably supported by one of the outer arm or the inner arm and the other end slidingly contacting the edge of the other arm, It is arranged on the left and right sides with respect to the connection fulcrum of the panta arm, the screw shaft of the electric cylinder is connected to the other end of one intermediate arm, and the nut of the electric cylinder is connected to the other end of the other intermediate arm. Then, the other end sides of both the intermediate arms approach each other by the operation of the electric cylinder,
An electric table lift apparatus, wherein the panta arm is configured to be extended and contracted while being separated. 2. The table lift device according to claim 1, wherein the movable fulcrum and the fixed fulcrum of the outer arm and the inner arm of the panta arm are set vertically and horizontally symmetrically with respect to the connection fulcrum. An electric table lift device, wherein the table is moved up and down while holding the axis of the screw shaft so as to cross the axis of the connection fulcrum.