JP2001341988A - Small screw jack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive small screw jack having common components and reduced machining cost and being applicable to a relatively small load. SOLUTION: The screw jack comprises a body case 1, on which rotationally driven female screw bodies 12, 13 are rotatably supported, and a screw shaft 20 threaded to the female screw bodies 12, 13, passing through the body case 1. The body case 1 has bearing portions 4 of the female screw bodies 12, 13 and a pair of split cases 2, 2 having symmetrical shapes where supporting holes 5 for the screw shaft 20 are provided. The screw shaft 20 having the same screw thread 21 throughout the total length is formed in a sectional D-shape by chamfering part of the outer periphery face to be a flat face 22. Two stopper nuts 23 with set screws 24 to be mounted at both ends of the screw shaft 20 are formed in the same shape and made in common. Two screw shaft guides 25 to be fitted to the supporting holes 5 in the body case 1 are formed in the same shape with guide holes 26 each having a sectional D-shape being the same as the sectional shape of the screw shaft 20 and made in common.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw provided with a main body case rotatably supported by a female screw body which is driven to rotate, and a screw shaft screwed to the female screw body and penetrating through the main body case. The present invention relates to a jack, and particularly to a small screw jack used for an application having a relatively small load.

[0002]

2. Description of the Related Art Screw jacks are used for various lifting devices and other various applications. Further, there is a large structural difference depending on the magnitude of the load used, and the number of parts is large.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a small-sized screw jack suitable for an application with a relatively small load, at a low cost, by making the components common and reducing the processing cost.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a main body case in which a female screw body which is driven to rotate is rotatably supported, and the main body case is screwed with the female screw body. A screw jack provided with a screw shaft penetrating therethrough, wherein the main body case comprises a pair of split cases having a symmetrical shape provided with a bearing portion of the female screw body and a bearing hole of the screw shaft, Are provided with the same thread over the entire length, and a part of the outer peripheral surface is chamfered into a flat surface to form a D-shaped cross section. The two stopper nuts with set screws have the same shape and are common, and the two screw shaft guides fitted in the bearing holes of the main body case have the same D-shape as the cross-sectional shape of the screw shaft. Mounting holes with a cross-sectional shape Digit was formed in the same shape, characterized in that it is common.

[0005] The two screw shaft guides serve both as a bellows mounting bracket and a screw shaft cover mounting bracket.

[0006] The screw jack is a traveling nut type in which an operating nut moves along the screw shaft, and the two stopper nuts with set screws are the same as the two.
Instead of the two screw shaft guides, they are fitted into both bearing holes of the main body case and fixed to the screw shaft.

Further, as a preferred embodiment, the pair of split cases are provided with eight mounting holes for both connection and jack mounting at symmetrical positions, and four mounting holes are used for connection. The remaining four mounting holes are configured to be used for mounting jacks.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show that a screw shaft 20 penetrating through a main body case 1 reciprocates in the axial direction, and a distal end screw portion 2
An example in which the present invention is applied to a screw jack of a type used for raising and lowering or reciprocating an actuated member (not shown) attached to a screwdriver 0a is shown.

As shown in FIGS. 5 and 6, the main body case 1 comprises a pair of split cases 2 and 2 having a symmetrical shape. Each split case 2 has a worm shaft 1 serving as an input shaft.
0, a bearing portion 4 of a worm wheel 12 serving as a female screw body that meshes with the worm shaft 10 and is driven to rotate, and a bearing hole 5 of the screw shaft 20 are provided. Also, the two split cases 2 and 2 are provided with four mounting holes 6 for coupling and four mounting holes 7 for jack mounting, respectively, at symmetrical positions, and a bolt 8 inserted into the mounting hole 6 for coupling is provided. Nut 9
Then, the two divided cases 2 and 2 are combined, and the main body case 1 is assembled. In addition, the bolt 8 is attached to the mounting hole 7 for mounting the jack.
Can be inserted to connect the two divided cases 2 and 2. In this case, the mounting holes 6 are used for jack mounting.

The worm shaft 10 is rotatably supported via a bearing 11 fitted in the bearing portion 3, and input shafts 10 a connected to both ends protrude from the main body case 1. The worm wheel 12 has a female screw 13 through which a screw shaft 20 is screwed, and is rotatably supported via a bearing 14 fitted in the bearing portion 4.

The screw shaft 20 is provided with the same triangular thread 21 over the entire length, and a part of the outer peripheral surface is chamfered into a flat surface 22 except for a tip screw portion 20a for attaching an actuated member. The shape is formed in a D shape.

The stopper mounted adjacent to the screw end 20a of the screw shaft 20 and the stopper mounted at the rear end of the screw shaft 20 have the same shape and are common. It is composed of a hexagon nut 23 and a set screw 24 that presses against the flat surface 22 (see FIG. 3). Also,
The two screw shaft guides 25 fitted in the bearing holes 5 on both sides of the main body case 1 also have the same shape and are shared, and FIG.
As shown in the figure, a guide hole 26 having the same D-shaped cross-section as the cross-section of the screw shaft 20 is provided.
0 is slidably penetrated and supported in the axial direction in a state where it is prevented from rotating. The screw shaft guide 25 is 4
It is fixed to the split case 2 using two bolts 27. The screw shaft guide 25 on the front side has a screw shaft 20.
Is attached and fixed. The tip of the bellows 28 is fixed from both sides using two hexagonal nuts 23 for stopper attached to the tip of the screw shaft 20. Also, the main body case 1 is attached to the screw shaft guide 25 on the rear side.
A screw shaft cover 29 accommodating the screw shaft 20 projecting rearward from the rear is fixedly mounted.

In the above configuration, when the worm wheel 12 is driven to rotate via the worm shaft 10 by an electric motor (not shown) connected to the input shaft 10a, the screw shaft screwed into the female screw 13 of the worm wheel 12 is provided. The driven member 20 (not shown) attached to the tip screw portion 20a is moved in the axial direction by rotating the worm wheel 12 in the forward and reverse directions because the screw shaft 20 prevents rotation of the worm wheel 20. Elevate or reciprocate.

FIG. 7 shows an example in which the present invention is applied to a traveling nut type screw jack. The same components as those of the screw jack shown in FIGS.
The same reference numerals are given and the description is omitted.

In the traveling nut type screw jack, since the screw shaft 20 does not move in the axial direction but merely rotates, as shown in FIG. 7, both screw holes 5, 5 of the main body case 1 are provided in FIG. Hexagon nuts 23, 23 for stoppers are fitted instead of the screw shaft guides 25 shown. The hexagonal nuts 23 for the stopper are attached to the screw shaft 20 screwed to the female screw 13 of the worm wheel 12 by a felt ring 30.
And fixed to the screw shaft 20 using set screws 24 on both sides of the bearings 14 and 14. The rear end of the screw shaft 20 is covered with a seal cap 31.

On the other hand, a traveling nut 32 is screwed into the screw shaft 20 projecting forward from the main body case 1, and an actuated member (not shown) is connected to the traveling nut 32 in a non-rotating state.

In the above configuration, when the worm wheel 12 is rotationally driven via the worm shaft 10 by an electric motor (not shown) connected to the input shaft 10a, the screw shaft 20
Rotates in a fixed position together with the worm wheel 12, and the traveling nut 32 screwed to the screw shaft 20 moves along the screw shaft 20. And worm wheel 1
When the screw shaft 20 is rotated in the forward and reverse directions by 2, the traveling nut 32 reciprocates along the screw shaft 20, and the actuated member connected to the traveling nut 32 moves up and down or reciprocates.

[0019]

As described above, in the screw jack according to the present invention, the components such as the main body case, the stopper nut with the set screw and the screw shaft guide are shared and simplified, and the screw shaft extends over the entire length. With the same thread,
In addition to the common use of the moving screw and the screw for mounting the actuated member at the tip, a part of the outer peripheral surface is chamfered to a flat surface instead of the keyway, reducing the processing cost. Can be greatly reduced, and the price of a small screw jack having a relatively small load can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing a preferred embodiment of a screw jack according to the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 1;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 1;

FIG. 5 is a plan view of a divided case constituting the main body case.

FIG. 6 is a partial longitudinal sectional view showing a combined state of both divided cases constituting the main body case.

FIG. 7 is a longitudinal sectional front view showing another embodiment of the screw jack according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body case 2 Split case 4 Bearing part 5 Bearing hole 6,7 Mounting hole 10 Worm shaft 12 Worm wheel 13 Female screw 20 Screw shaft 20a Tip screw part 21 Thread 22 Flat surface 23 Hex nut for stopper 24 Stop screw 25 Screw shaft guide 26 Guide hole 30 Felt ring 32 Traveling nut

Claims (4)

[Claims] 1. A screw jack comprising: a main body case rotatably supported by a female screw body rotatably driven; and a screw shaft screwed to the female screw body and penetrating through the main body case, The main body case is composed of a pair of split cases having a symmetrical shape provided with a bearing portion of the female screw body and a bearing hole of the screw shaft, and the screw shaft is provided with the same screw thread over the entire length. A part of the outer peripheral surface is chamfered into a flat surface to form a D-shaped cross section, and two stopper nuts with set screws mounted on both ends of the screw shaft have the same shape and are shared. The two screw shaft guides fitted in the bearing holes of the main body case are formed in the same shape provided with mounting holes having the same D-shaped cross-sectional shape as the cross-sectional shape of the screw shaft, That they are common Small screw jack to butterflies. 2. The two screw shaft guides serve both as a bellows mounting bracket and a screw shaft cover mounting bracket.
Small screw jack as described. 3. The screw jack is a traveling nut type in which an operating nut moves along the screw shaft, and the two stopper nuts with set screws are replaced with the two screw shaft guides in the main body case. 2. The small screw jack according to claim 1, wherein said small screw jack is fitted into said both bearing holes and fixed to said screw shaft. 4. The small screw jack according to claim 1, wherein said pair of split cases are provided with symmetrical positions of eight mounting holes for both connecting and jack mounting.