JPH0144558Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement of a screw jack used for hoisting heavy objects in civil engineering construction, bridge construction, shipbuilding, transportation of heavy machinery, etc.

(Prior Art) This type of conventional screw jack is usually arranged concentrically with the axis of the driven bevel gear A of a pair of bevel gears A and B that mesh at right angles, as shown in Fig. 2. The lower end of the screw rod C is fixed, and the screw cylinder D is screwed into the screw rod C, and its rotation is prevented by a key (not shown) provided on the main body E. Screw tube D
It is configured to move up and down. The load applied to the screw rod C is supported by a thrust bearing G disposed between the bottom F of the main body and the driven bevel gear A, and generally a thrust type ball bearing is used.

(Problems to be Solved by the Invention) The conventional screw jack has a relatively simple structure, is easy to handle, and has high practical utility. However, there are still problems with conventional screw jacks that need to be solved.

First, the ball type thrust bearing G
The lower side of the bevel gear A is supported by the bevel gear A, and since the bevel gear A is formed into a thick flat plate, the height of the screw rod C and the screw tube D is smaller than the height of the main body E. It is difficult to make it relatively large, and as a result, there is a problem that the lifting dimension of the jack cannot be increased, or that the height of the main body E is required to be large for a certain lifting height. The second problem is that the bevel gear A is supported by a ball-shaped thrust bearing G.
The problem is that when the load applied to the screw rod C is large, the bevel gear A is rotated thereby, causing the screw tube D to naturally descend. In order to prevent this natural descent, it is necessary to specially provide a brake device or the like on the side of the driving bevel gear B, which poses a problem of increasing the manufacturing cost of the screw jack. Furthermore,
The third problem is that the ball-type thrust bearing that supports the lower surface of the driven bevel gear A has a relatively weak supporting force against lateral loads, so the applied load becomes large and its direction is slightly deviated from the axis, causing the screw cylinder to If a torsional load is applied to D or the screw rod C, the position of the driven bevel gear A will shift, making it difficult for the screw jack to operate smoothly.

The purpose of this invention is to solve the above-mentioned problems, and it is possible to reduce the height of the jack body for a certain lifting size, and also to reduce the weight of the jack without the need for a special brake device. To provide a screw jack which can be lifted up safely and which can always operate smoothly.

(Means for Solving the Problems) The present invention includes a set of bevel gears, a screw rod fixed to the driven side bevel gear, a screw tube screwed into the screw rod, and the front side bevel gear In the screw jack consisting of a thrust bearing for supporting the screw cylinder, and a main body for slidably holding the screw tube, the driven side bevel gear 5 is formed into a substantially cylindrical cross-sectional shape, and its side wall 5a The driven bevel gear 5 is rotatably supported by providing a bevel tooth 5b on the upper end surface, and by interposing a sheet-like slat decking part 3 between the bottom surface 5d of the driven bevel gear 5 and the bottom part 2 of the main body. Furthermore, a ring-shaped presser plate 9 is fitted to the inner lower part of the main body 1, and the inner circumferential portion 9a of the presser plate 9 is attached to a stepped portion 5c formed on the outer circumferential surface of the side wall of the driven side bevel gear 5. The basic structure of the invention is to allow the driven bevel gear 5 to be slidably engaged and to regulate the position of the driven bevel gear 5.

(Function) When the driven bevel gear 5 is rotated via the drive bevel gear, the screw rod 4 is rotated, and the screw cylinder 6 screwed therein is moved up and down.

The load applied to the screw tube 6 is the driven bevel gear 5.
It is supported by a sheet-like slide pad 3 disposed on the bottom surface 5d. Further, the driven bevel gear 5 is
It is always held in a fixed position by a presser plate 9 fitted below the main body 1 and slidably engaged with a stepped portion 5c on the outer peripheral surface of the side wall of the driven bevel gear 5, so that a large load cannot be applied. Also, no positional deviation occurs.

Further, the frictional resistance between the bottom surface 5d of the driven bevel gear 5 and the sliding part 3 functions as a brake when a jack load is applied, thereby preventing the screw rod 4 from falling naturally due to the jack load. .

(Example) Hereinafter, an example of the present invention will be described based on FIG. 1.

In Figure 1, 1 is a cylindrical main body, 2 is a main body 1
The bottom of the main body is screwed to the lower end of the main body, 3 is a fluororesin sheet-like sliding part laid on the bottom of the main body 2, 4 is a screw rod with a thread formed on the outer circumferential surface, 5 is the lower end of the screw rod 4 A driven bevel gear 6 is concentrically welded to the screw rod 4, and a screw tube 7 is screwed into the screw rod 4 via a female screw body 4a.
is a screw for preventing rotation of the screw tube 6 screwed into the main body 1, and the tip of the screw 7 is slidably fitted into a key groove (not shown) formed vertically on the outer peripheral surface of the screw tube 6. are doing.

Also, 8 is a jack head, 9 is a presser plate, and 10
11 is a screw for fixing the female threaded body 4a, and 11 is a drive device for a driving bevel gear (not shown) that meshes with the driven bevel gear 5.

The driven side bevel gear 5 has a cylindrical cross-sectional shape, and bevel teeth 5b are formed on the upper end surface of the side wall 5a. Further, on the outer circumferential surface of the side wall 5a on the lower side, an inner circumferential portion 9a of a presser plate 9, which will be described later, is provided.
A shallow recessed stepped portion 5c is formed which is slidably engaged with. Further, the bottom surface 5d of the cross-sectional driven bevel gear 5 is finished into a smooth planar shape, and the sliding part 3 is interposed between the bottom surface 5d and the bottom surface 5d of the driven side bevel gear 5.
It is rotatably supported on the top. That is, the bottom surface 5d of the driven bevel gear 5, the sliding pad 3, and the top surface of the main body bottom portion 2 form a thrust bearing portion 12 such as the screw rod 4.

The presser plate 9 is a ring body with a square cross-sectional shape, and has a so-called two-piece structure in which the ring body is formed by abutting two ring pieces.

The presser plate 9 has its outer circumferential portion 9b connected to the main body bottom 2.
It is fixed to the lower inner circumferential portion of the main body 1 by fitting between the engaging step portion 1a formed on the lower inner circumferential surface of the main body 1, and is firmly clamped vertically by tightening the main body bottom 2. It is fixed. In addition, the presser plate 9
The inner peripheral part 9a is slidably engaged into the marked part 5c on the outer peripheral surface of the side wall of the driven side bevel gear 5,
As a result, the position of the driven bevel gear 5 is regulated.

By rotating the screw rod 4 by the drive device 11 via the drive side bevel gear and the driven side bevel gear 5, the screw cylinder 6 moves up and down.

When the jack is not in use, the lower end of the screw cylinder 6 is lowered to the inside of the cylindrical driven bevel gear 5, thereby increasing the lifting dimension of the jack.

The downward load applied to the screw tube 6, the screw rod 4, etc. is supported by the thrust bearing section 12 mainly composed of the sliding part 3 etc., and the lateral and upward loads applied to the driven bevel gear 5 are supported by the presser foot. It is supported by plate 9.

(Effects of the invention) As described above, in the present invention, the driven gear 5 is a cylindrical body with a cross-sectional shape, so that the lower end of the screw cylinder 6 can be lowered to the lower inside of the driven gear 5 when the jack is not operating. I can do it. As a result, if the height dimension of the main body 1 is the same, the lifting dimension will be significantly increased compared to the conventional jack, and if the jacking dimension is the same, the height of the main body can be reduced. This improves the workability of the jack and allows the jack to be fully installed even in a narrow space.

Further, in the present invention, since the thrust bearing part 12 is formed by the sliding part 3, the bottom surface 5d of the driven bevel gear 5, and the top surface of the main body bottom part 2,
Compared to the case of using a conventional ball-type thrust bearing, the height of the space required to store the bearing part 12 is smaller, which is advantageous in terms of the jack lift-up dimension, etc., and reduces sliding when using the jack. Since the friction resistance of the pads 3 properly functions as a braking device to prevent the screw rod 4 from falling naturally, the safety of the jack can be ensured without providing a special braking device.

Furthermore, since the side portion of the driven bevel gear 5 is slidably supported by the holding plate 9, the position of the driven bevel gear 5 is always correctly regulated.
The jack operates smoothly at all times.

As mentioned above, the present invention has excellent practical effects.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the screw jack according to the present invention. FIG. 2 is a longitudinal sectional view of a conventional screw jack. DESCRIPTION OF SYMBOLS 1... Main body, 2... Bottom of main body, 3... Sliding parts, 4... Screw rod, 5... Driven bevel gear, 5a... Side wall, 5b... Bevel teeth, 5c...
Stepped part, 5d...Bottom surface, 6...Screw tube, 9
...Press plate, 9a...Inner peripheral part, 9b...Outer peripheral part,
11... Drive device, 12... Thrust bearing section.

Claims (1)

[Scope of utility model registration request] A set of bevel gears, a screw rod fixed to the driven side bevel gear, a screw tube screwed into the screw rod, a thrust bearing portion supporting the front side bevel gear, and the screw tube. In a screw jack consisting of a main body that is slidably held, the driven side bevel gear 5 is formed into a substantially cylindrical cross-sectional shape, and bevel teeth 5b are formed on the upper end surface of the side wall 5a.
A sheet-like sliding part 3 is interposed between the bottom surface 5d of the driven bevel gear 5 and the bottom part 2 of the main body 2 to rotatably support the driven bevel gear 5. A ring-shaped presser plate 9 is fitted to the inner lower portion, and the inner circumferential portion 9a of the presser plate 9 is slidably engaged with the stepped portion 5c formed on the outer circumferential surface of the side wall of the driven side bevel gear 5. , a screw jack characterized by regulating the position of the driven bevel gear 5.