JPH0353767Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an improvement of a bending correction machine for correcting the bending of a rod-shaped member such as a reinforcing bar.

[Technical background of the invention and its problems]

At construction sites and the like, portable bending correction machines are used to correct the bending of reinforcing bars. As this bending correction machine, the applicant of the present application has developed a portable bending correction machine with excellent handling and workability and has filed a patent application (Japanese Patent Laid-Open No. 59-21433).

This bending correction machine consists of a casing body with an oil tank inside, and a casing body installed inside the casing body.
A pump mechanism for pumping the oil stored in the oil tank, and a cylinder chamber formed in the casing body to which pressure oil is supplied from the pump mechanism, which is disposed slidably in the axial direction and has a piston rod joined to the back surface. A piston with a release mechanism, a switching valve disposed in an oil passage communicating the pump mechanism and the cylinder chamber and switching a pressure oil supply route, a receiving arm of a rod-shaped member attached to the front part of the casing body, A correction hook is attached to the tip of the piston rod and cooperates with the receiving arm to correct the bending of the rod-shaped member.

The release mechanism provided in the piston includes a plurality of through holes provided in the piston in the axial direction, and a valve body disposed in the through hole in a state biased by a spring from behind. Further, each of the valve bodies has, at its tip, protrusions in opposite directions that protrude from the end surface of the piston into the cylinder chamber.

Pressure oil is supplied into the cylinder chamber and the piston moves, but when the piston moves to its final position,
The protrusion of the valve body attached to the piston comes into contact with the end wall surface, and the valve body retreats against the spring. This opens a through hole, and the pressure oil in the cylinder chamber on one side flows into the cylinder chamber on the other side. This stops the movement of the piston and prevents the pump mechanism and electric motor from being overloaded.

However, in a release mechanism with such a structure, there is a risk that the protrusion attached to the tip of the valve body may bend, or when the piston rod is rotated together with the hook, it may get galled against the end wall surface and break. There is.

Therefore, it has been desired to develop a release mechanism that has a simple structure and is free from failure.

[Purpose of invention]

The present invention has been made with these points in mind, and it is an object of the present invention to provide a bending correction machine for correcting the bending of bar-shaped members such as reinforcing bars, which has a simple structure and is equipped with a release mechanism that does not cause failures. purpose.

[Summary of the idea]

The present invention includes a casing body with an oil tank provided therein, a pump mechanism disposed inside the casing body to pump oil stored in the oil tank, and a pump mechanism formed inside the casing body to pump pressure oil from the pump mechanism. A cylinder chamber to be supplied, a piston with a release mechanism that is slidably disposed in the cylinder chamber in the axial direction and has a piston rod connected to the back, and an oil passage that communicates between the pump mechanism and the cylinder chamber. A switching valve that switches the pressure oil supply route,
A bending rod-shaped member comprising a receiving arm for the rod-shaped member attached to the front part of the casing body, and a correction hook attached to the tip of the piston rod and working together with the receiving arm to correct the bending of the rod-shaped member. In the correction machine for correction, the release mechanism provided on the piston includes a through hole provided through the piston in the axial direction, and a size smaller than the diameter of the through hole and slightly longer than the length in the axial direction. It has a valve rod and a valve head that is provided at both ends of the valve rod and is larger than the diameter of the through hole, and is mounted with the valve head protruding from the front end surface and the rear end surface of the piston, respectively, toward the cylinder chamber side. It is characterized by consisting of a release valve.

[Example of idea]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is an external view of the bending correction machine according to the present invention. In the figure, reference numeral 11 denotes an electric motor, and the electric motor 11 is connected and fixed to the rear end of the casing body 12. At the front part of the casing body 12, there is a receiving arm 13 for a rod-shaped member R such as a reinforcing bar.
is attached to be rotatable around the outer periphery of the casing body 12. A pair of receiving arms 13 are attached at intervals, and a correction hook 14 is disposed between the receiving arms 13 to correct the bending of the rod-shaped member R in cooperation with the receiving arms 13. This hook 14 has a concave shape so as to be able to apply a pushing or pulling correction force to the rod-shaped member R, and is attached to the tip of a piston rod 15, which will be described later. Reference numeral 16 is a handle provided with a switch S for the electric motor 11, and reference numeral 17 is an auxiliary handle attached to the front portion of the casing body 12.

FIG. 1 is a sectional view showing the internal structure of a bending correction machine 10 according to the present invention. An oil tank 18 in which oil is stored is provided inside the casing body 12, and a pump mechanism 1 that pumps the oil in the oil tank 18 is provided.
9 are arranged. The pump mechanism 19 includes a cam portion 21 formed at the tip of a motor shaft 20 and a piston 22 that is reciprocated by the cam portion 21, and generates high-pressure oil by reciprocating the piston 22. The casing body 12 is
It is divided by a vertical wall 23 into an oil tank 18 in which a pump mechanism 19 is arranged and a cylinder chamber 24, and the pump mechanism 19, oil tank 18, and cylinder chamber 24 are communicated with each other by an oil passage provided in the vertical wall 23. .

The oil passages include an oil supply passage 25 connected to the pump mechanism 19, a retreat oil passage 26 having an opening on the front side of the cylinder chamber 24, a forward oil passage 27 having an opening on the rear side of the cylinder chamber 24, and an oil tank 18. The oil flow path is configured to be switched by a switching valve 30 provided in the vertical wall 23.

The switching valve 30 has a substantially cylindrical shape and is rotatably inserted into a cylindrical cylinder 29 formed within the vertical wall 23 . In the cylindrical cylinder 29, the other ends of the oil supply passage 25, the backward oil passage 26, the forward oil passage 27, and the return passage 28 are all open.

3 and 4 are partially enlarged views showing the state in which the switching valve 30 is inserted. The switching valve 30 is formed in a left-right symmetrical shape, and is provided with a through passage 31 in the direction of the symmetrical axis, and tapers 32a, 32a, and 32a, each starting from a point spaced apart by a distance of Δl from the end of the through passage 31, respectively. 32b is formed. These tapers 32a, 32b and each oil passage mentioned above are connected to one taper 32a and the cylindrical cylinder 29.
When the oil supply passage 25 and the retreating oil passage 26 are communicated with each other by the space 33a formed between the space 33a and the inner wall, the forward oil passage 27 and the return passage 28 are connected to the other taper 32b and the inner wall of the cylindrical cylinder 29. (see FIG. 3), and the retreat oil passage 26 and the return passage 2 are communicated with each other by the space formed between the taper 32a and the other taper 32a (see FIG. 3).
The oil supply passage 25 and the forward oil passage 27 are arranged in such a relationship that when they are communicated with each other, the space formed between the oil supply passage 25 and the forward oil passage 27 is communicated with the other taper 32b (see FIG. 4). There is. Also, the oil supply passage 25
The opening diameter d opening into the cylindrical cylinder 29 is
The distance Δl from the end of the through passage 31 to the ends of the tapers 32a and 32b is made slightly larger. The return passage 28 has openings 2 at positions facing the openings of the oil supply passage 25, the backward oil passage 26, and the forward oil passage 27 to the cylindrical cylinder 29, respectively.
8a, 28b, and 28c. The switching valve 30 has an opening 28a in its widening end.
and 28c or a groove 34 that communicates with the openings 28b and 28c is formed, and this groove 34 further communicates with the through passage 31.

The switching operation of the switching valve 30 can be performed by rotating a lever 48 (FIG. 2) connected to the end of the valve.

Inside the cylinder chamber 24, a piston 35 having a piston rod 15 joined to the back surface is disposed so as to be freely slidable in the axial direction.
The piston rod 15 is moved backward by the pressure oil supplied to the rear side 24b of the cylinder chamber 24 (the left side in FIG. 1), and the piston rod 15 is moved forward by the pressure oil supplied to the rear side 24b of the cylinder chamber 24 (the right side in FIG. 1). It's starting to become easier.

The piston 35 is provided with a through hole 36 in the axial direction, and the release valve 3 is connected to the through hole 36.
7 is mounted so as to be movable in the axial direction. The release valve 37 includes a valve rod 37a which is movably inserted into the through hole 36 with a gap and has a diameter smaller than the diameter of the through hole 36 and a length slightly larger than the length in the axial direction. , a valve head 37 having a diameter larger than the diameter of the through hole 36, which is fixed to both ends of the valve rod 37a.
b, 37c. These valve heads 3
7b and 37c are arranged to protrude from the front and rear end surfaces of the piston 35 toward the cylinder chambers 24a and 24b, respectively, and are connected to the valve rod 3.
The sealing surfaces on the connection side with 7a can be brought into close contact with the front and rear end surfaces of the piston 35, respectively.

A through hole 38 is further bored in the piston 35 in a direction perpendicular to the through hole 36 .
Also, oil is provided around the outer circumference of the piston 35 at the front and rear sides (left and right sides in FIG. 1) of the communication hole 38, respectively, so that the oil can flow only from the communication hole 38 toward the cylinder chambers 24a and 24b. Seal 39
a and 39b are attached.

The piston 35 further includes a cylinder chamber 24a,
A safety valve 40 is provided that is activated when a pressure above a predetermined level is generated within 24b. This safety valve 40
a through hole 41 provided to penetrate the piston 35 in the axial direction; a valve body 40a having a shape capable of closing the through hole 41 disposed within the through hole 41;
and a spring 40b that urges the valve body 40a toward the opening of the through hole 41. A pair of the safety valves 40 are arranged in opposite directions so that the valve bodies 40a face the front cylinder chamber 24a and the rear cylinder chamber 24b, respectively.

Next, the operation of this embodiment having such a configuration will be explained.

First, it is decided whether the rod-shaped member R to be corrected should be corrected by pulling (correcting by moving the hook 14 backward) or by pressing (correcting by moving the hook 14 forward), and then the switching valve 30 is selected by operating lever 48. In FIG. 1, the switching valve 30
is in position to be corrected by tension. Next, as shown in FIGS. 1 and 2, the rod-shaped member R is
It is inserted between the tip projection 13a of the receiving arm 13 and the hook 14. In the case of tension correction, the rod-shaped member R is placed in contact with the front side of the protrusion 13a as shown in the figure, and in the case of pressure correction, it is arranged so as to be brought into contact with the rear side of the protrusion 13a.

After setting the rod-shaped member R and the bending correction machine in this way, when the switch S of the electric motor 11 is pressed, the motor shaft 20 and the cam 21 are rotationally driven, and the piston 22 moves back and forth to suck the oil in the oil tank 18. Compress and generate pressure oil. The pressure oil generated by the pump mechanism 19 is fed under pressure to the cylindrical cylinder 29 through the oil supply passage 25, and is supplied to the retreating oil passage 26 through the space 33a, as shown in FIG. The pressure oil supplied to the retreating oil passage 26 is introduced into the front cylinder chamber 24a, thereby pressing the piston 35 and moving it backward (rightward in FIG. 2). As the piston 35 retreats, the piston rod 15 and the hook 14 move backward, and the rod-shaped member R is pulled and bent between it and the receiving arm 13 for correction.

During this time, the valve head 37b of the release valve 37
is brought into close contact with the front end surface of the piston 35 by hydraulic pressure,
The pressure inside the front cylinder chamber 24a is maintained at high pressure. Further, the oil in the rear cylinder chamber 24b is returned to the oil tank 18 through the forward oil passage 27, the space 33b, and the return passage 28.

When the piston 35 moves backward to near the final position, the release valve 3 attached to the piston 35
The valve head 37c of No. 7 abuts against the end surface of the vertical wall 23. The subsequent movement of the piston 35 causes the release valve 37 to move relative to the front side of the piston 35 (to the left in FIG. 1) within the through hole 36. As a result, the valve head 37b separates from the front end surface of the piston 35, and the high pressure oil in the front cylinder chamber 24a fills the gap between the front end surface of the piston 35 and the valve head 37c, and the gap between the through hole 36 and the valve rod 37a. and flows into the rear cylinder chamber 24b. As the oil pressure in the front cylinder chamber 24a decreases, the piston 35, piston rod 15, and hook 14 stop moving.

When pressure oil is released through the through hole 36, if the release valve 37 does not move sufficiently and the amount of released oil is insufficient, the high pressure oil in the through hole 36 passes through the communication hole 38 and seals the oil seal. 39b
The oil flows to the side and flows out into the rear cylinder chamber 24b while pushing the oil seal 39b. This reliably stops the movement of the piston 35 and prevents overload from being applied to the pump mechanism 19 and the electric motor 11.

Furthermore, when the oil pressure in the cylinder chamber 24 becomes abnormally high due to the release valve 37 not operating, etc., the valve body 40a moves against the spring 40b, and the pressure oil flows from the high pressure side to the low pressure side through the through hole 41. It flows into the cylinder chamber 24 on the side.

Next, when correcting the bending of the rod-shaped member R by pressing, the rod-shaped member R is held on the hook 1 as described above.
4 and the receiving arm 13, and the switching valve 30 is rotated to the position shown in FIG. 4 by operating the lever 48. During this switching operation, since the opening diameter d of the oil supply passage 25 is made slightly larger than the distance Δl from the end of the through passage 31 to the ends of the tapers 32a and 32b, the switching valve 30
The oil supply passage 25 is not completely sealed by the distance Δl. Therefore, during the switching operation of the switching valve 30, the electric motor 11 is driven,
Even if pressure oil is supplied from the pump mechanism 19,
This pressure oil is released to the return passage 28 through the through hole 31 and the groove 34, so that the load on the pump mechanism 19 will not suddenly increase and cause a failure.

After switching the switching valve 30 to the position shown in FIG. 4, pressure oil is transferred from the pump mechanism 19 to the oil supply passage 25.
When the pressure oil is supplied to the forward movement oil passage 27 through the space formed between the taper 32b and the inner wall of the cylindrical cylinder 29, the pressure oil flows into the forward movement oil passage 27 and further into the rear cylinder chamber 24b. As a result, with the valve head 37c of the release valve 37 brought into close contact with the rear end surface of the piston 35, the piston 35 moves forward in the left direction in FIG. 1, and the piston rod 15 and the hook 14 perform a forward pressing movement. When the piston 35 moves near the final forward position, the valve head 37 of the release valve 37 moves, contrary to what has been described above.
b comes into contact with the end wall 42, and the release valve 37 moves relative to the piston 35 in the right direction in FIG.
Pressure oil in the rear cylinder chamber 24b is released to the front cylinder chamber 24a. This stops the forward movement of the piston 35 and piston rod 15. Also, during forward movement, the front cylinder chamber 24
The oil a passes through the retreat oil passage 26, the space formed between the taper 32a of the switching valve 30, and the inner wall of the cylindrical cylinder 29, and then reaches the return passage 28 and the oil tank 1.
Returned to 8.

Similarly, when switching the switching valve 30 from the position shown in FIG. 4 to the position shown in FIG. Failure of the electric motor 11 due to overload is prevented.

When working on the bending correction machine 10 according to this embodiment, the operator usually holds the handle 16 and the auxiliary handle 17 and places the receiving arm 13 and the hook 14 on the rod-shaped member R to be corrected. .
In this case, if the receiving arm 13 and the hook 14 cannot be placed in a position where the work is easy due to the position of the worker and the position of the rod-shaped member, the auxiliary handle 17 or the receiving arm 13 may be manually rotated. , can be set in the optimal position.

[Effect of idea]

As explained above, in the present invention, the release mechanism attached to the piston has an extremely simple structure and does not have elongated protrusions, springs, etc. as in the past, so there is a risk of failure during use. There are almost no Further, in the event that the release mechanism malfunctions, the safety valve mechanism is activated, so that no overload is applied to the pump mechanism, electric motor, etc.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a bending correction machine according to the present invention, FIG. 2 is an external view thereof, and FIGS. 3 and 4 are partially enlarged views of a switching valve. 12...Casing body, 13...Receiving arm, 14...Hook, 15...Piston rod,
18...Oil tank, 19...Pump mechanism, 24...Cylinder chamber, 25...Oil supply passage, 26...Reverse oil passage, 27...Forward oil passage, 28...Return passage, 30...Switching Valve, 35... Piston, 3
6...Through hole, 37...Release valve, 37a
...Valve rod, 37b, 37c...Valve head, 38...Communication hole, 40...Safety valve.

Claims (1)

[Scope of utility model registration request] a casing body having an oil tank provided therein; a pump mechanism disposed within the casing body to pump oil stored in the oil tank; and a cylinder formed within the casing body and supplied with pressure oil from the pump mechanism. A piston with a release mechanism, which is disposed slidably in the axial direction in the cylinder chamber and has a piston rod connected to the back; A piston is disposed in an oil passage that communicates the pump mechanism and the cylinder chamber, and supplies pressure oil. a switching valve that switches the path between the front side and the rear side of the cylinder chamber; a receiving arm of a rod-shaped member attached to the front part of the casing body; and a receiving arm of the rod-shaped member attached to the tip of the piston rod and working together with the receiving arm A correction hook for correcting bending;
In the bending correction machine for correcting the bending of a rod-shaped member, the release mechanism provided on the piston has a through hole that is provided through the piston in the axial direction; The valve rod has a dimension longer than the axial length of the hole, and a valve head provided at both ends of the valve rod and larger than the diameter of the through hole, and the valve head extends from the front end surface and rear end surface of the piston, respectively, into the cylinder chamber. A bending correction machine characterized by comprising: a release valve mounted in a protruding state on the front side and the rear side;