JPH0867495A - Continuously working jack - Google Patents

Abstract

PURPOSE: To minimize a working space occupied by a device for moving a heavy cargo. CONSTITUTION: Two pieces of hollow pistons 2, 3 are provided in the same cylinder 1 in a jack used for a device to move a heavy cargo while chucking a PC steel strand wire, etc., and an end part 3b of one piston 3 of the two hollow pistons 2, 3 facing against each other is formed as a recessed part, an end part 2b of the other piston 2 is formed as a protruded part, and the recessed part and the protruded part are formed to be engaged with each other with a play. Additionally, both of the pistons 2, 3 are actuated in opposite directions by providing racks 6a, 6b respectively on ends of external shafts 2a, 3a of both of the pistons 2, 3 and having them engaged with each other through a pinion provided on the outer periphery of the cylinder 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jack for moving a heavy load or the like vertically, forward and backward, or left and right.

[0002]

2. Description of the Related Art Conventionally, as a device of this kind for generally moving a heavy object, as shown in FIG.
Two center hole jacks 32 and 33 are coaxially provided at a required distance, and a PC steel wire 35 connected to a heavy object 34 is inserted into the hollow holes of the center hole jacks 32 and 33, and the respective center hole jacks are inserted. There is used a device for moving the heavy load 34 while alternately chucking the PC steel stranded wire 35 by the chucks 36, 37 provided on the 32, 33. The center hole jack 32,
Reference numeral 33 is configured to be operated via the pipes 32a, 32b and 33a, 33b for supplying or discharging the pressure hydraulic oil, respectively.

In this generally used apparatus, the two chucks 36, 37 and the jacks 32, 33 arranged on the respective chucks are coaxially arranged, and the stroke length of each jack is also taken into consideration. This required a long working space.

As an invention for improving this problem, Japanese Patent Publication No. 4-
The jack for continuous transfer of heavy objects disclosed in Japanese Patent No. 71839 is known. According to the invention described in the publication, FIG.
As shown in FIG.
a, 42b and a jack 43a for supporting the chuck 44b,
43b and 43b are arranged upside down with respect to each other, as shown by the arrow, to share the space required for the lengths and strokes of the jacks, thereby reducing the working space. Reference numeral 46 in the figure denotes a jack base that receives the full load of heavy objects.

[0005]

However, in the above-described conventional heavy load moving device, Japanese Patent Publication No. 4-71839.
Although the working space in the longitudinal direction is reduced in the invention disclosed in Japanese Patent Publication, there is some effect, but it is further required to further reduce the working space in the orthogonal direction and simplify the device. It is about to be done.

Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide a continuously operating jack in which the work space occupied by a device for moving a heavy object is minimized.

[0007]

In order to achieve the above object, the present invention is a jack used for a device for moving a heavy load while chucking a PC steel strand or the like, and the jacks are alternately continuous in opposite directions by a pressure medium. We have developed a jack with two working hollow pistons inside the same cylinder.

The ends of one of the two hollow pistons facing each other can be fitted in a recess, the end of the other piston can be fitted in a projection, and the recess and the projection can be loosely fitted. Formed.

Further, racks are fixed to the outer shaft end portions of both pistons so as to face each other, and a pinion is provided on the outer circumference of the cylinder. By doing so, the other piston is operated in the opposite direction to the operating direction of the one piston.

[0010]

According to the continuously operating jack of the present invention, when two hollow pistons provided in the same cylinder stroke in a direction in which they approach each other, the two pistons face each other without collision. Since the ends are loosely fitted to each other to share the stroke space, it is possible to reduce the work space occupied by the device for moving the heavy object to the minimum in both the vertical and horizontal directions.

Further, by providing a mechanism for operating both pistons in opposite directions via the rack and the pinion, the operation of each jack is conventionally performed by hydraulically operating the return stroke of the pistons. No need for oil return piping.

[0012]

Embodiments of the present invention will be specifically described below with reference to the drawings. 1 to 5 show an embodiment of the present invention, FIG. 1 is a cross-sectional view of a continuous operation jack, FIG. 2 is a view for explaining the operation of a piston, and FIGS. 3 and 4 are a return stroke of the piston by a rack and a pinion. Explanatory drawing, FIG. 5 is a sectional view showing a meshing portion of the rack and the pinion.

As shown in FIG. 1, the continuous operation jack of the present invention is provided with two hollow pistons 2 and 3 inside a cylinder 1. The piston 2 has an outer shaft 2a and an inner shaft 2b thereof, and the piston 3 has an outer shaft 3a and an inner shaft 3b thereof fitted to the cylinder 1 in an airtight and slidable manner. The stroke lengths of 3 are set to be the same.

Further, the air chamber 4b of the piston 2 and the air chamber 5b of the piston 3 are provided with ventilation holes 7a and 8a in the side wall of the cylinder 1 so that air can freely flow in and out.

Further, a recess 3c is formed at the end of the inner shaft 3b of the piston 3, and the outer diameter of the inner shaft 2b of the piston 2 is sized so that the inner diameter of the recess 3c can be loosely fitted. Further, a working chamber 4a for operating the piston 2 is provided with a supply / discharge port 7 for supplying / discharging working oil as a working medium, and a working chamber 5a for operating the piston 3 is provided with a supply / discharge port 8 for supplying / discharging working oil. Has been.

On the outer circumference of the cylinder 1, there is provided a gear case 6e in which a pinion 6c is rotatably housed via a pinion shaft 6d, while an outer shaft 2 of the piston 2 is provided.
The rack 6a is fixed to the chuck case 10 at the end a, the rack 6b is fixed to the cap 22 at the end of the outer shaft 3a of the piston 3, and the tooth surfaces of the racks 6a and 6b are opposed to each other so that the rack 6a is placed inside the gear case 6e. By engaging the pinion with the racks 6a and 6b so that the pinion is engaged with each other, the rack 6a, the rack 6b and the pinion are connected to each other.
The strokes of the piston 2 and the piston 3 are always moved in opposite directions via c.

Further, the screw 1 at the end of the external shaft 2a of the piston 2
4a and a screw 14b at the end of the outer shaft 3a of the piston 3 are provided with chucks 9 and 19 each having a hollow hole through which the PC steel wire 16 is inserted.

In the chuck 9, the chuck case 10 having a tapered hole is fitted with a split claw 11 having a taper corresponding to the tapered hole, and the split claw 11 is screwed into a screw 13 of the chuck case 10. The coil spring 15 elastically pressed between the cap 12 and the fixed cap 12 pushes the taper portion into the chuck case 10 and chucks the PC steel stranded wire 16. .

The chuck 19 has a chuck case 20.
The split claw 21 that is attached by a screw 24 via a cap 22 screwed to the screw 14b at the end of the outer shaft 3a of the piston 3 and fits into the taper hole of the chuck case 20 is elastic between the end face of the outer shaft 3a and the split claw 21. The PC steel stranded wire 16 is chucked by being elastically pressed by the attached coil spring 23.

Further, a ram chair 17 is provided on the lower end surface of the cylinder 1, and the lower end of the ram chair 17 contacts the reaction force base 18 so that the entire load when towing a heavy object can be suspended. There is.

Next, the operation of moving the heavy load 24 by operating the continuous operation jack of this construction will be described. As shown in FIG. 1, first, the PC steel strand 16 connected to the heavy object 24 is inserted through the two pistons 2 and 3 and the central holes of the two chucks 9 and 19 attached to the pistons 2 and 3, respectively. At this time, the split claws 11 and 21 fitted in the taper portions of the chucks 9 and 19 are elastically pressed by the coil springs 15 and 23 elastically attached to the split claws 11 and 21, respectively, so that the PC steel strand 16 is split into the split claws 11 and 21. The inner diameter of 21 automatically chucks lightly.

When the pistons 2 and 3 provided in the cylinder 1 are started to operate from the position shown in FIG. 1 while maintaining the above state, first, pressure is applied from the hydraulic oil supply / discharge port 8 to the working chamber 5a of the piston 3. The piston 3 starts to rise by supplying oil. When the piston 3 moves up, the rack 6b fixed to the external shaft end on the piston 3 side also moves up at the same time, so that the rack 6a meshed with the pinion is lowered, and the rack 6b interlocks with the rise of the piston 3. The piston 2 is lowered.

In this case, as the piston 3 rises, the air in the air chamber 5b on the piston 3 side is discharged into the atmosphere through the ventilation hole 8a, and the ventilation hole 7a is formed in the air chamber 4b on the piston 2 side.
Air is automatically sucked in through. In this way, when the pistons 2 and 3 are actuated toward each other,
As shown in FIG. 2, the outer shape of the inner shaft 2b of the piston 2 is loosely fitted in the recess 3c at the end of the inner shaft 3b of the piston 3 to share the moving space of the pistons 2 and 3.

Simultaneously with the start of the ascent of the piston 3 as described above, the inner diameter of the split claw 21 of the chuck 19 provided at the lower portion of the piston 3 is strongly pushed into the outer circumference of the PC steel strand 16 by friction, and the taper portion is strongly pressed. The outer circumference of the steel stranded wire 16 is firmly tightened by the split claws 21 so that it is integrated with the chuck 19 and pulled upward.

On the other hand, the split claw 11 of the chuck 9 provided on the upper part of the piston 2 is pushed up by the rise of the PC steel wire 16 and the lowering of the piston 2 to release the tightening.
The space between the outer circumference of the PC stranded wire 16 and the inner diameter of the split claw 11 becomes free. This makes it possible to move the chuck 9 downward relative to the rising PC steel wire 16. In this case, the heavy load 2 supported by the chuck 19
The load of 4 is hung on the reaction force base 18 via the ram chair 17.

Next, when the pistons 2 and 3 are actuated from the closest position shown in FIG. 2, by supplying pressure hydraulic oil from the hydraulic oil supply / discharge port 7 to the working chamber 4a of the piston 2, the piston 2 Rises, and at the same time, the rack 6a fixed to the outer shaft end of the piston 2 rises, pushing down the rack 6b via the pinion 6c,
The piston 3 is lowered in conjunction with the rise of the piston 2.

In the stroke in which the pistons 2 and 3 operate in the direction of separation, the air in the air chamber 4b on the piston 2 side is discharged into the atmosphere through the ventilation hole 7a, and the piston 3
The air is automatically introduced into the side air chamber 5b through the ventilation hole 8a to enable the operation, and the pistons 2 and 3 are returned to the original positions shown in FIG.

At the same time as the piston 2 starts to rise, the PC steel strand 16 is firmly tightened on the outer periphery by the tapered portion of the split claw 11 of the chuck 9 provided on the upper portion of the piston 2, and becomes integral with the chuck 9. Be pulled up. On the other hand, the split claw 21 of the chuck 19 provided at the lower portion of the piston 3 is pushed up by the rise of the PC steel wire 16 and the lowering of the chuck 19 to loosen the taper portion, and
The outer circumference of the C stranded wire 16 and the inner diameter of the split claw 21 become free. This makes it possible to move the chuck 19 relatively upward with respect to the rising PC steel wire 16.

As described above, by repeating the operation of the pistons 2 and 3, it is possible to continuously pull the PC steel wire 16 to move the heavy object. In addition,
The PC steel stranded wire 16 chucked by the chucks 9 and 19 in the present embodiment is not limited to this, and any material that can withstand chucking of the chucks 9 and 19 can be applied.

[0030]

According to the continuous operation jack of the present invention, 1
By providing two pistons in each cylinder, the work space occupied by the heavy load moving device can be set in both vertical and horizontal directions as compared with the case where two or more jacks are used in the conventional heavy load moving device. It can be reduced to the minimum.

Further, since the two pistons are operated in opposite directions via the rack and the pinion, the return pipe for hydraulic oil, which is provided in each jack in the conventional apparatus, becomes unnecessary.

[Brief description of drawings]

FIG. 1 is a sectional view of a continuously operating jack showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating the operation of a piston.

FIG. 3 is an explanatory diagram of an operation stroke of a piston by a rack and a pinion.

FIG. 4 is an explanatory diagram of an operation stroke of a piston by a rack and a pinion.

FIG. 5 is a sectional view of a meshing portion of a rack and a pinion.

FIG. 6 is an explanatory view of a conventional heavy load moving device.

FIG. 7 is an explanatory view of a conventional heavy load moving device.

[Explanation of symbols]

 1 Cylinder 2,3 Piston 4b, 5a Working chamber 4a, 5b Air quality 6a, 6b Rack 6e Gear case 7,8 Hydraulic oil supply / discharge port 7a, 8a Vent hole 9,19 Chuck 10,20 Chuck case 11,21 Split claw 12,22 Cap 13,14,24 Screw 15,23 Coil spring 16 PC steel stranded wire 17 Ramchair 18 Reaction force base

Claims (3)

[Claims] 1. A jack for use in a device for moving a heavy object while chucking a PC steel wire or the like, wherein two hollow pistons which are continuously operated alternately in opposite directions by a pressure medium are provided in the same cylinder. A continuous operation jack characterized by comprising: 2. An end of one of the two opposed pistons of the two hollow pistons can be fitted in a recess, an end of the other piston can be fitted in a projection, and the recess and the projection can be loosely fitted. The continuously operated jack according to claim 1, wherein the jack is formed. 3. A piston is provided by fixing racks facing each other on the outer shaft end portions of both pistons, providing a pinion on the outer circumference of the cylinder, and engaging the opposing racks with each other via the pinion. 2. The continuous operation jack according to claim 1, wherein the operation of the other piston is operated in a direction opposite to the operation direction of the above.