JPH02298474A - Fluid operating tool - Google Patents

Abstract

PURPOSE:To drive a nail continuously with a small stroke force by composing this tool so that a piston repeats a reciprocating movement between an advance and stop position and the specific position where retreat is detected by a retreat detecting means. CONSTITUTION:When a pressure fluid of a pressure source 1 is fed to a piston front chamber 6a and piston rear chamber 6b- via the flow pass 5d of a switch valve 5, the pressures of the piston front chamber 6a and piston rear chamber 6b are increased but a piston 7 is advanced because of the pressure receiving area of the rear end face being larger than that of the front end face having a piston rod 8. A stroke force is thus generated on the piston rod 8 and a nail 9 is driven into a plate member 12. When the piston rod 8 is stopped after its driving the nail 9, the advance of the piston 7 is checked and so the pressure in the piston rear chamber 6b is increased by pulsation and becomes higher than the feeding pressure of the pressure source 1. Consequently, an unload valve 11 forms a passage, switching a switch valve 5 and retreating the piston 7 to a standby position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a fluid-operated tool that drives a nail or the like using fluid pressure.

[Conventional technology]

A fluid-operated tool that drives fasteners such as nails using fluid pressure may have a structure in which a reciprocating piston is installed in a cylinder, as disclosed in JP-A No. 47-9515, for example. It is commonly used. In such a configuration, a high fluid pressure such as compressed air is applied to the rear chamber of the piston of the cylinder, and the nail is driven in by the striking force generated by moving the piston at high speed.

[Problems to be Solved by the Invention] However, in the conventional structure mentioned above, in order to drive a nail with one blow, the cylinder and piston must be made larger to increase the striking force.

Therefore, the tool body becomes large and heavy, reducing operability. Furthermore, if the impact force is large and the strength of the member into which the nail is driven is low, there is a risk that the member will be destroyed by the impact force of the tool.

Therefore, in order to downsize the cylinder and piston,
- It is possible to reduce the impact force per impact and drive the nail in several times, but in this case, the lever operation that supplies pressurized fluid to the cylinder and discharges the pressure fluid from the cylinder for each impact is necessary. This poses a problem in that it is necessary to repeat the process, and it is also necessary to move the striking position according to the position of the nail, making the operation complicated.

(Means for Solving the Problems) In order to solve the above problems, a fluid-operated tool according to the present invention includes a piston that reciprocates in a cylinder by the pressure of a pressure fluid, and a piston that is prevented from moving forward. forward stop position detection means for detecting the stopped position by the pressure increase in the piston rear chamber when the piston is prevented from moving forward;
When the stop position of the piston is detected by the retraction detection means for detecting that the piston has retracted to a predetermined position and the forward stop position detection means, the flow path of the pressure fluid is switched so as to retract the piston, while - ” - When the retraction detection means detects the retraction of the screw I-
It is characterized by comprising a switching means for switching the flow path of the pressure fluid so as to move the cylinder forward.

[Function] According to the above configuration, when the forward movement of the piston is blocked during impact, the pressure in the rear chamber of the piston increases due to the reaction.
The stop position of the piston is detected by the forward stop position detection means, the flow path of the pressure fluid is switched by the switching means, and the piston begins to retreat. When the piston retreats to a predetermined position, the retreat of the piston is detected by the retreat detecting means, the flow path of the pressure fluid is switched by the switching means, and the piston begins to move forward. This behavior causes
Since the piston repeats reciprocating motion between a stop position when moving forward and a predetermined position when retreating, nails can be continuously driven with a small striking force.

Therefore, it is possible to reduce the size and weight of the tool body by making the cylinder smaller, and it is also possible to reduce damage to the member into which the nail is driven.

In addition, by continuously striking, not only does it eliminate the need to repeatedly operate the lever to switch between pressurizing and depressurizing the rear chamber of the piston for each strike, but the striking position can also be moved according to the position of the nail. There will be no need for it.

〔Example〕

An embodiment of the present invention will be described below based on FIG.

As shown in FIG. 1, a pressure source 1 serves as a pressure fluid supply source.
A tank 2 for discharging pressure fluid is connected to a cylinder 6 via a trigger valve 3, a safety valve 4, and a switching valve 5 for switching a pressure supply route.

The trigger valve 3 has a lever 3a, and this lever 3
It is provided so that the flow paths 3b and 3c can be switched by operation a. The flow path 3b is formed to prevent pressure fluid from flowing from the pressure source 1 and to allow pressure fluid from the safety valve 4 to flow to the tank 2, while the flow path 3c
is formed to allow pressure fluid from the pressure source 1 to flow to the safety valve 4 and to allow pressure fluid from the safety valve 4 to flow to the tank 2. When the lever 38 is pushed against the elastic force of the spring 3d, the I-rigger valve 3 switches to the flow path 3c, and when the pressing force of the lever 3a is released, it switches to the flow path 3b.

The safety valve 4 has a switch 4a, and is provided so that flow paths 4b and 4C are switched by operating the switch 4a. The flow path 4b is formed to prevent pressure fluid from flowing from the trigger valve 3 and to allow pressure fluid from the switching valve 5 to flow to the trigger valve 3, while the flow path 4c is formed to prevent pressure fluid from flowing from the trigger valve 3. It is formed to allow pressure fluid to flow and also to allow pressure fluid from the switching valve 5 to flow to the 1-liga valve 3. When the switch 4a is pushed against the elastic force of the spring 4d, the safety valve 4 opens the flow path 4C.
When the pressing force of the switch 4a is released, the flow path is switched to the flow path 4b. Further, by interlocking the safety valve 4 and the switch 4a with a bushing lever 10, which will be described later, the supply of pressure fluid from the pressure source 1 can be stopped in an emergency.

The switching valve 5 serving as a switching means has two pressure receiving surfaces 5a and 5b, and is provided so as to switch between the flow paths 5C and 5d based on the difference in force acting on the pressure receiving surfaces 5a and 5b.

The pressure receiving surface 5a is provided so that pressure fluid is supplied from the pressure source 1 via the trigger valve 3, while the pressure receiving surface 5b has a larger pressure receiving area than the pressure receiving surface 5a and has a bore of a cylinder 6 which will be described later. ) 6c to be supplied with pressure fluid. Further, the flow path 5C is formed to allow pressure fluid to flow from the safety valve 4 to the piston front chamber 6a in the cylinder 6, and to flow pressure fluid from the piston rear chamber 6b in the cylinder 6 to the safety valve 4. On the other hand, the flow path 5d is formed to allow pressure fluid to flow from the safety valve 4 to the piston front chamber 6a and the piston rear chamber 6b. The switching valve 5 has a pressure receiving surface 5a
When the force acting on the pressure receiving surface 5b becomes larger than the force acting on the pressure receiving surface 5b, the channel is switched to the channel 5C, while when the force acting on the pressure receiving surface 5b becomes greater than the force acting on the channel 5a, the channel 5d is switched.
It is now possible to switch to .

The cylinder 6 is provided with a piston 7 in its inner chamber so as to be able to reciprocate in its axial direction, and is also provided with a bow 6c serving as forward stop position detection means. Beau+-6
c is provided at a position such that it opens when the piston arm is in the standby position as shown and closes when the piston 7 moves forward from the standby position, and is designed to detect that the piston 7 has retreated to the standby position. It has become. The piston 7 is provided with a piston rod 8 extending from the inner chamber of the cylinder 6 to the outside thereof for axial force at the center of the front end surface thereof. On the outside of the front end of the cylinder 6,
A cylindrical holding member 6d for holding the nail 9 is provided around the movement of the piston rod 8. A bushing lever 10 that presses the switch 4a of the safety valve 4 to switch between the flow paths 4b and 4c is attached to the tip of the holding member 6d.

The unload valve 11, which serves as a retraction detection means, is supplied with pressure fluid from the pressure source 1 and the piston rear chamber 6b and given a pilot pressure, and when the pressure of the pressure source 1 is higher than the pressure of the piston rear chamber 6b. It is designed to close the flow path. Further, the unload valve 11 is activated by the piston rear chamber 6 due to the reaction when the piston 7 is stopped from moving forward.
When the pressure of b becomes higher than the pressure of the pressure source 1, the flow path is opened, and the pressure fluid acting on the pressure receiving surface 5b of the switching valve 5 connected to this flow path is passed through the safety valve 4 and the trigger valve 3. It is designed to be discharged to tank 2. In this manner, the unload valve 11 detects the position at which the piston 7 has stopped by detecting the pressure increase in the piston rear chamber 6b when the piston 7 is struck.

2, when the lever 3a of the trigger valve 3 is pressed, the flow path 3c is switched to the pressure receiving surface 5 of the switching valve 5.
Pressure fluid is supplied to a, and pilot pressure (=) is applied to b. Also, by pressing the holding member 6d of the cylinder 6 against the plate member 12, the switch 4 of the safety valve 4
When a is pushed by the bush lever 10, the flow path is switched to the flow path 4c.

On the other hand, in the switching valve 5, a trigger valve 4 is provided on the pressure receiving surface 5a.
Although pressure is applied to the bicot 1 through the pressure receiving surface 5b, a flow path 5c is formed, and the pressure fluid that has passed through the 1-riger valve 3 and the safety valve 4 flows through the pressure receiving surface 5b. It is supplied to the piston front chamber 6a. The pressure fluid of the piston front mass 6; 3 is supplied to the pressure receiving surface 5b via the boat 6C, and a pilot pressure is applied thereto.

However, since the pressure receiving area of the pressure receiving surface 5b is larger than the pressure receiving area of the pressure receiving surface 5a, the force acting on the pressure receiving surface 5b is
The force becomes larger than the force exerted by a, and the flow path is switched to the flow path 5d.

When the pressure fluid from the pressure source 1 is supplied to the piston front chamber 6a and the piston rear chamber 61] through the flow path 5d of the switching valve 5, the pressures in the piston front chamber 6a and the piston rear chamber 6b rise. Since the rear end surface of the piston 7 has a larger pressure receiving area than the front end surface having the piston rod 8, the piston 7 moves forward in the direction of the arrow in the figure. This generates an impact force on the piston rod 8 and drives the nail 9 into the plate member 12.

When the piston rod 8 drives the nail 9 and stops, the piston 7 is prevented from moving forward, so the pressure in the piston rear chamber 6b increases due to pulsation and becomes higher than the supply pressure of the pressure iru. For this reason, the unload' valve 11 forms a flow path, and the pressure fluid that has been supplied to the pressure receiving surface 5b of the switching valve 5 passes through the safety valve 4 and the I-RIGA valve 3 to the tank 2.
is discharged to. At this time, since pilot pressure is applied to the pressure receiving surface 5a, the switching valve 5 switches to the flow path 5c. Then, from the pressure source 1 to the piston front chamber 6
When pressure fluid is supplied to a, the piston rear chamber 6b
As the pressure fluid is discharged from the tank 2 to the tank 2, the piston 7 retreats to the standby position.

Thereafter, the above operation is repeated, and a striking force is applied to the piston rod 8 every time the piston 7 makes one reciprocation. When the nail 9 is driven to a predetermined position, the button lever 10 releases the suppression of the switch 4a of the safety valve 4 and switches to the flow path 1+b, or the lever 3a of the trigger valve 3 is switched to switch to the flow path 3b. Each time the supply of pressure fluid from the pressure source 1 to the cylinder 6 is cut off, the movement of the piston 7 is stopped.

In this embodiment, the switching valve 5 is configured to switch the flow paths 5c and 5d for the piston rear chamber 6b, but for example, the piston 7 may be configured such that the rear end surface has a larger pressure receiving area than the front end surface. When the piston front chamber 6a is moved forward, the piston front chamber 6a
Pressure oil is discharged from the piston rear chamber 6b and pressure oil is supplied to the piston rear chamber 6b. On the other hand, it may be configured such that the pressure oil is supplied to the piston front chamber 6a and the piston rear chamber 6b during retraction.

Also, regardless of the pressure receiving area of screws 1-7, forward movement ■, 1
During retraction, pressure oil is discharged from the piston front chamber 6a and is supplied to the piston rear chamber 6b, while at the time of retraction, pressure oil is supplied to the piston front chamber 6a and pressure oil is discharged from the piston rear chamber 6b. It may be configured so that

〔Effect of the invention〕

As described above, the fluid-operated tool according to the present invention includes a piston that moves reciprocally in a cylinder by the pressure of a pressure fluid, and a position where the piston is stopped when the piston is prevented from moving forward. When the stop position of the piston is detected by the forward stop position detecting means that detects by the pressure increase in the piston rear chamber, the backward detecting means that detects that the piston has retreated to a predetermined position, and the forward stop position detecting means, A switching means for switching the flow path of the pressure fluid so as to move the piston backward, and a switching means for switching the flow path of the pressure fluid so as to move the piston forward when the retraction detection means detects the retraction of the piston. be.

According to this, the piston repeats reciprocating motion between the stop position detected by the forward stop position detecting means and the predetermined position at which the retreat is detected by the backward detecting means, so that the piston can be continuously nailed with a small striking force. can be typed. Therefore, by making the cylinder smaller, the tool body can be made smaller and lighter, and damage to the member into which the nail is driven can be reduced. In addition to this, continuously 1]
By striking the piston, there is no need to repeatedly operate the lever to switch between pressurizing and depressurizing the rear chamber of the piston for each strike, and there is no need to move the striking position according to the position of the nail. This has the effect of improving operability.

[Brief explanation of drawings]

FIG. 1 shows one embodiment of the present invention, and is a circuit diagram showing the configuration of a fluid-operated tool. 5 is a switching valve (switching means), 6 is a cylinder, 6b is a piston rear chamber, 6c is a boat (backward detection means), 7 is a piston, and 11 is an unlower 1' valve (forward stop position detection means).

Claims (1)

[Claims] 1. A piston that moves reciprocally in a cylinder due to the pressure of a pressure fluid, and a forward stop position where the piston is prevented from moving forward and stops, which is detected by the pressure increase in the rear chamber of the piston when the piston is prevented from moving forward. a detection means, a retraction detection means for detecting that the piston has retracted to a predetermined position, and a flow path for pressure fluid so as to retract the piston when the stop position of the piston is detected by the forward stop position detection means. and switching means for switching the flow path of the pressure fluid so as to advance the piston when the retraction of the piston is detected by the retraction detection means.