JPH0536568Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention uses pressurized oil to move a piston, and uses a processing jig such as a cutter attached to the tip of the piston to perform predetermined cutting operations. This invention relates to a portable hydraulic processing machine for machining.

[Conventional technology]

For example, in construction work sites, civil engineering work sites, etc., a large number of reinforcing bars are used, and machining to cut the reinforcing bars into predetermined lengths or bend them at predetermined angles is required at the site. For this reason, various portable hydraulic processing machines called reinforcing bar cutters and reinforcing bar benders are used.

In this type of portable hydraulic processing machine, a piston is arranged to be able to reciprocate within a cylinder that constitutes a part of the main body, and a pair of chambers are moved within the cylinder by the piston head. Defined left and right. A return spring made of, for example, a compression coil spring is disposed in one chamber (second chamber). here,
A processing jig, for example, one of a pair of cutters, is attached to the tip of the piston, and the other cutter faces and is fixed to the housing.

In such a configuration, the start switch is operated after a workpiece such as a reinforcing bar is placed between the movable cutter at the tip of the piston and the fixed cutter on the housing. Then, the built-in motor is activated, the pump supplies pressurized oil from the reservoir to the other chamber (first chamber) of the cylinder, and the piston moves forward against the biasing force of the return spring. Then, the reinforcing bars are cut by a movable cutter and a fixed cutter.

Immediately after disconnection, the relief valve provided in the piston head is opened to prevent abnormal pressure build-up in the first chamber, and the outflow passage communicating with the reservoir via the second chamber is connected to the first chamber. is released, allowing pressurized oil to drain into the reservoir. Here, the return spring is compressed during the advancement of the piston, and sufficient biasing force is stored in the return spring. Therefore, when the relief valve is released, the pressurized oil in the first chamber is drained into the reservoir via the second chamber, and the piston moves back to its initial position due to the biasing force of the return spring. .

Even when the piston moves in either the forward or backward path, the volumes in the first chamber and the second chamber of the cylinder change as the piston moves.
Pressurized or unpressurized oil flows into and out of each chamber in response to volume changes.

However, if pressurized oil and the like are not moved properly, negative pressure will be generated within the chamber, making it difficult to move the piston smoothly. Therefore, a flexible air bag that prevents the generation of negative pressure is installed with its interior open to the atmosphere, and when negative pressure is generated in the first and second chambers, it expands and creates a negative pressure. Prevent pressure build-up. The air bladder also ensures smooth movement of the piston by deflating.

The open end of the flexible air bladder is removably attached to a mounting member, and the mounting member is disposed in a mounting hole formed in the end surface of the housing. Since this attachment hole communicates with the reservoir, the air bag is housed within the reservoir.

However, pressurized oil is transferred from the first chamber to the second chamber.
When the air bag is drained into the reservoir via the chamber, there is a risk that the air bag together with the mounting member may be pushed out from the mounting hole and removed from the main body. In particular, in a type of portable hydraulic processing machine that does not have a built-in return spring, pressurized oil is supplied to the second chamber to cause the piston to move on its return path.
However, since the second chamber is always in communication with the reservoir, when pressurized oil is supplied to the second chamber, the pressure of the pressurized oil acts on the air bladder in the reservoir, pushing the air bladder to the outside. There is a big risk.

Therefore, in known portable hydraulic processing machines, a configuration is generally adopted in which a step portion having a smaller diameter on the outer side is formed in the mounting hole, as exemplified in Japanese Utility Model Publication No. 18568/1983. With this configuration, the mounting member is not obstructed by the stepped portion and is not pushed out.
Air bag separation can be prevented.

[The problem that the idea aims to solve]

When selecting the material for the flexible air bladder, oil resistance is taken into consideration, and since it is repeatedly inflated and deflated, durability is also taken into consideration. however,
No matter how durable the material is to mold the air bag, if the portable hydraulic processing machine is used for a long time,
Replacement of the air bladder is inevitably required.

However, as described above, since the mounting hole is provided with a stepped portion that prevents the air bag from detaching, the mounting member and the air bladder are obstructed by the stepped portion and cannot be removed through the mounting hole. Therefore, in known portable hydraulic processing machines, the main body must be disassembled to replace the air bag. However, disassembling and assembling the main body is complicated and time consuming. In addition, the disassembly causes the oil in the reservoir and the first and second chambers of the cylinder to flow out and must be refilled after assembly of the body.
Here, due to the complex internal structure of the reservoir,
It takes time to remove air, and refueling the reservoir requires at least 30 minutes. In addition, there is a risk of contaminating the surrounding area due to oil spillage.

The purpose of this invention is to provide a portable hydraulic processing machine in which the flexible air bag can be replaced without disassembling the main body.

[Means to solve the problem]

To achieve this purpose, according to this invention,
A piston is arranged in a cylinder so that it can reciprocate,
When pressurized oil is supplied to the chamber of the cylinder, the piston moves on the outward path and the machining jig at the tip of the piston performs the specified machining process.Then, the piston moves on the return path and returns to the initial position, opening the inside of the cylinder. In a portable hydraulic processing machine in which a flexible air bag that is open to the atmosphere is placed in a reservoir that communicates with a chamber to prevent the generation of negative pressure within the cylinder, the opening of the flexible air bag A mounting hole is formed in the end face of the housing, the end of which is removably attached to the mounting member, and which communicates with the reservoir and into which the air bag can be inserted from the outside together with the mounting member, and an obstacle that prevents the air bag from being pushed out from the mounting hole. object is provided in the housing.

[Effect]

In the above configuration, the air bag is inserted and installed from the outside into the mounting hole on the end face of the housing, so the air bag can be replaced without disassembling the main body.
Air bladders can be replaced quickly without oil spills.
It's easy to do. Also, since there are obstacles,
The air bag will not be pushed out of the mounting hole.

〔Example〕

Hereinafter, embodiments of this invention will be described in detail with reference to the drawings.

As shown in FIG. 1, a portable hydraulic processing machine 10 according to the invention includes a substantially cylindrical main body 12 made of a cast alloy, and the main body includes a housing 1.
3, a cylinder 14, a pump case 15, and a motor housing 16. A piston 17 is disposed within the cylinder 14 so as to be able to reciprocate, and a processing jig 22 such as a cutter is attached to the tip of the piston rod.

A return spring 24, such as a compression coil spring,
It is arranged within the chamber of the cylinder 14. A relief valve 26 is also attached to the piston head 28. This relief valve 26 is
Relief hole 30 formed in piston head 28
The valve rod 32 is loosely fitted into the valve rod, a large-diameter valve head 34 integral with the valve rod, and a tight spring 36 wound around the small-diameter portion of the valve rod.

The pump, motor, etc. are housed in a pump case 15 and a motor housing 16 on the right side of the cylinder, and oil is stored in a reservoir 41 formed in the housing 13 on the left side of the cylinder. The reservoir 41 is constantly communicated with the chamber 14b, and the oil is
It is sent from the reservoir through the chamber 14b and the flow path 42 to the pump in the pump case 15, and after being pressurized by the pump, it is sent to the cylinder 1 through the flow path 44.
4 chambers 14a.

A flexible air bladder 50 is disposed in the reservoir 41 to prevent negative pressure from building up in the chambers 14a, 14b. The air bladder 50 is housed in a mounting hole 52 formed in the end face of the housing 13, and this mounting hole communicates with the chamber 14b via the reservoir 41.

As can be clearly seen from FIG. 2, one end of the air bag 50 is open, and the open end is removably fixed to the attachment member 54. The air bag 50 is attached to the attachment member 54, for example, as follows.

First, the nut 56 is pushed into the air bag 50 through the opening. The attachment member 54 is formed in a cylindrical shape with a bottom, and the air bag 50 is attached to the attachment member 54 by screwing a bolt 58 loosely fitted into a hole 60 at the bottom into a nut 56 inside the air bag. . Since the bolt 58 has a through hole 61 that communicates with the inside of the air bag 50, the inside of the air bag is opened to the atmosphere, and the expansion and contraction of the air bag is ensured. Further, a filter 62 is housed inside the mounting member 54 to prevent damage to the air bag 50 due to dust in the air. An O-ring 64 is disposed between the mounting member 54 and the mounting hole 52.

Here, as will be described later, since the pressurized oil supplied to the chamber 14a flows into the chamber 14b, the pressure of the pressurized oil acts on the air bag 50 in the attachment hole 52 communicating with the chamber 14b. and,
In a configuration in which the mounting hole 52 does not have a step, the air bag 50
There is a possibility that it may come off from the mounting hole 52. Therefore, it is necessary to provide an obstacle that prevents the air bag 50 from detaching.In the embodiment, a set screw 68 is screwed into a tap hole 66 provided in the housing 13, and a lockable, for example, annular shape at the tip of the set screw is provided. Locking groove 7
0 is formed on the outer periphery of the mounting member 54.

In such a configuration, the set screw (obstruction) 68
This prevents the attachment member 54 from moving and prevents the air bag 50 from detaching. The configuration for preventing detachment of the air bag 50 is not limited to the illustrated configuration; for example, as shown by the dashed line in FIG. 71 may be screwed to the housing 13. Here, a hole is formed in the center of the cover 71 so as not to obstruct the supply of air to the air bag 50.

As described above, since the attachment hole 52 does not have a step, the air bag 50 can be easily replaced without disassembling the main body 12. That is, the air bladder 50 can be replaced without disassembling the main body 12 and removing the housing 13 from the main body. The air bag 50 is replaced, for example, as follows.

In other words, the air bag 50 can be easily removed from the attachment hole 52 by unscrewing the set screw 68 to release the engagement with the attachment member 54 and then taking out the attachment member to the outside. Then, remove the filter 62,
By unscrewing the nut 56 and bolt 58, the air bag 50 is removed from the mounting member 54. Thereafter, the nut 56 is set in another air bag 50 and the procedure is reversed to complete the replacement of the air bag.

Note that the portable hydraulic processing machine 10 having the above configuration operates as follows.

First, when the start switch 72 is operated to operate the motor in the motor housing 16, the pressurized oil is supplied to the first pump by the pump in the pump case 15.
As can be seen from the figure, from the reservoir 41, the flow path 4
2, 44 and is supplied to the chamber 14a of the cylinder. Then, the piston 17 moves to the left against the biasing force of the return spring 24, and a predetermined machining is performed by the machining jig 22 at the tip of the piston. When pressurized oil is supplied to the chamber 14a, the pressure of the pressurized oil acts on the surface of the valve head 34 of the relief valve, so that the back surface of the valve head and the surface of the piston head come into close contact, leaving the relief hole 30 closed. Piston 17 moves to the left. When the piston 17 moves forward enough and the predetermined machining is completed, the relief valve tightening spring 3
6 or the rear end of the valve rod 32 comes into contact with the bottom 15 of the housing 13, separating the back surface of the valve head 34 from the surface of the piston head, so that the relief hole 30 opens into the chamber 14a,
The pressurized oil in the chamber 14a flows into the chamber 14b and flows into the reservoir 41 via the chamber 14b.
, thereby draining the chamber 14a.
This prevents abnormal pressure rise inside the tank.

When the chambers 14a and 14b are brought into communication, the return spring 24 accumulated during the movement of the piston 17
The biasing force causes the return stroke of the piston. In other words, the biasing force of the return spring 24 causes the pressurized oil in the chamber 14a to be transferred to the chamber 14a.
The piston 17 moves to the right and returns to its initial position while draining into the reservoir 41 via b.

When the piston 17 returns to the initial position, the head of the return spring 24 contacts the inner wall of the cylinder, the back surface of the valve head 34 comes into close contact with the surface of the piston head, and the relief hole 30 is closed.

By the way, as the piston 17 moves to the right, the volume of the chamber 14b increases. By the pressurized oil in the chamber 14a flowing into the chamber 14b through the flow path 44, the chamber 14b
The increase in volume is compensated for. Here, chamber 1
The amount of oil corresponding to the change in volume of chamber 1 is
If the liquid does not flow into the chamber 14b, negative pressure will be generated within the chamber 14b, making it difficult for the piston 17 to move smoothly. However, a flexible air bag 50 is disposed in a mounting hole 52 communicating with the chamber 14b, and the inside of the air bag is open to the atmosphere. Therefore, even if the amount of oil flowing in is insufficient, the air bladder 50 will expand appropriately to compensate for the lack of oil amount, preventing the generation of negative pressure, and ensuring smooth movement of the piston 17. .

Note that while the piston 17 is moving forward, the chamber 1
The volume of 4b decreases, and oil corresponding to the decrease in volume is transferred from the reservoir 41 to the chamber 14b, the flow path 42,
44 into the chamber 14a,
Smooth movement of the piston is not ensured. and,
Reduction in the volume of the chamber 14b and the reservoir 41,
If the amount of oil flowing out from the chamber 14b is not balanced, negative pressure may occur. In this case as well, it goes without saying that the air bladder 50 is appropriately inflated to maintain balance, thereby preventing the generation of negative pressure.

The above-described embodiments are for illustrating the invention, and are not intended to limit the invention in any way, and may be modified within the technical scope of the invention. Needless to say, all modified items are also included in this invention.

For example, the mounting member 54 may include a filter 6 inside.
2 is formed in a cylindrical shape with a bottom, but it is not limited to this and can take various shapes.

In the embodiment, the piston 17 is returned by the biasing force of the return spring 24, but the piston may be returned by supplying pressurized oil to the chamber 14b.

[Effect of idea]

As described above, in the portable hydraulic processing machine according to the present invention, the stepped portion is removed from the air bag attachment hole, and the air bag can be installed by inserting the air bag into the attachment hole from the outside. With this configuration, the air bladder can be replaced without disassembling the main body. Therefore, there is no oil leakage, and the air bag can be replaced quickly and easily.

In addition, since there are obstacles in the housing,
The air bag will not be pushed out from the mounting hole.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view of a portable hydraulic processing machine according to the invention, and FIG. 2 is a partially enlarged view of the portable hydraulic processing machine. 10...Portable hydraulic processing machine, 12...Main body,
13...Housing, 14...Cylinder, 14
a, 14b...Cylinder chamber, 15...Pump case, 16...Motor housing, 17...
... Piston, 24 ... Return spring, 26 ... Relief valve, 41 ... Reservoir, 50 ... Flexible air bag, 52 ... Mounting hole, 54 ... Mounting member, 56 ... Nut, 58 ... Bolt, 61...
...through hole, 62...filter, 68...set screw, 70...locking groove.

Claims (1)

[Claims for Utility Model Registration] (1) A piston is disposed in a cylinder so that it can reciprocate, and when pressurized oil is supplied to the chamber of the cylinder, the piston moves in the outward path and the processing jig at the tip of the piston is moved. After performing the specified machining,
The piston moves on the return path and returns to the initial position,
In a portable hydraulic processing machine, a flexible air bag whose inside is open to the atmosphere is placed in a reservoir communicating with the chamber to prevent the generation of negative pressure inside the cylinder. The open end of the housing is removably attached to the mounting member, and a mounting hole is formed on the end face of the housing that communicates with the reservoir and into which the air bag can be inserted from the outside together with the mounting member, and prevents the air bag from being pushed out from the mounting hole. A portable hydraulic processing machine with obstacles installed in the housing. (2) The portable device according to claim 1, wherein the obstacle is a set screw that is screwed into a tap hole formed in the housing, and the tip of the set screw prevents the attachment member from coming out of the attachment hole. Hydraulic processing machine. (3) The portable hydraulic processing machine according to claim 2, wherein a locking groove capable of locking the tip of the set screw is formed on the outer periphery of the mounting member. (4) The portable hydraulic processing machine according to claim 1, wherein the obstacle is a cover that partially blocks the outlet of the mounting hole and is screwed to the end face of the housing.