JPS6022162B2 - Near tool safety equipment - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention supplies high-pressure air to the horn of an air tool such as an air grinder or a sander when the rotation reaches a set maximum rotation or higher to issue an alarm and also protect the tool. This relates to a safety device that stops or decelerates the speed below the set maximum rotation speed.

Conventional technology and its problems In general, air tools such as air grinders and sanders that obtain rotational energy from high-pressure air to perform various tasks have safety standards for governor devices to ensure that they rotate within safe tolerances. Its installation is mandatory.

However, the high-pressure air supplied to the air tool is not necessarily clean air at the pressure set for the tool. Sometimes high-pressure air that is higher than the set pressure is supplied, or water droplets are sometimes supplied to the air tool along with the air. In such a case, there is a risk that the rotor will rotate at a rotation speed higher than the maximum safe rotation set due to the characteristics of the air tool. To prevent this, the rotor shaft is equipped with a governor mechanism, but the water supplied with the air can cause the governor mechanism to rust and not operate properly in the event of an abnormality, resulting in damage to the rotor or burnout. Furthermore, in the case of an air grinder, the grinding wheel of an air grinder may burst due to the centrifugal force caused by its high-speed rotation, which can be very dangerous. In order to prevent this, a system has been proposed in which a safety device for preventing overspeed rotation is provided separately from the conventional speed governor, for example, in Tokokukan Sho 51-50080. However, this known safety device shuts off the air supply to the air motor chamber and stops the tool when the governor does not operate properly and the grinder, etc. reaches a set maximum rotation speed. However, it is possible to achieve that goal. However, it is not clear why the tool stopped, whether the safety device was activated due to an abnormality in the governor, or whether the tool stopped due to damage to the air motor, bearing, reduction gear, etc. In the present invention, when the governor is no longer operating normally and reaches an abnormally high rotation speed, a safety device is activated to decelerate or stop the rotor and to warn of the abnormality. This was done with the purpose of making the tool sound audible, thereby notifying the cause of the tool stoppage.

Means for Solving the Problems The present invention provides an auxiliary shaft with an inscription that is concentrically connected to the end of the rotor shaft that rotates due to the supply of high-pressure air, and a shaft that is slidably inserted into the outer periphery of the auxiliary shaft. In addition, the ball holder is equipped with a cap with a concave inner circumference, the ball is held between the cap of the ball holder and the flange of the auxiliary shaft, and the ball holder is made of metal to hold the ball with pressure. It consists of a spring that presses toward the passenger side and a horn provided in a part of the main body, and an air inflow hole that opens and closes to the governor room by the sliding of the ball holder, and is connected to the air inflow hole and connected to the horn. drilling an air hole into the auxiliary shaft;
The air supply hole leading to the cylinder chamber is connected to the governor chamber, and due to an abnormality in the governor, the rotor reaches a high speed exceeding the set rotation speed, and the balls are pushed toward the outer circumference by centrifugal force. Then, the air inflow hole of the auxiliary shaft is closed, and part of the air supplied to the rotor chamber is also supplied to the horn side to issue an alarm, and when the rotor rotation increases further, the ball is popped out and the air is supplied. Iron is inserted into the air hole to cut off the air supply to the rotor, and the rotor is stopped while issuing an alarm to maintain the safety of the tool.

EXAMPLE The present invention will be explained below based on an example of an air grinder shown in the drawings.
If it is, the safety device of the present invention can be applied.

In the figure, 1 is the main body of the air tool, and a rotor 2 is rotatably supported in the cylinder of the main body 1, and the rotation of the rotor 2 is transmitted to the grinding wheel via a power transmission mechanism 3, either directly or after deceleration. do.

In addition, a bearing 4 is provided at the shaft end of the rotor 2 to support the rotor shaft in the main body 1, and a part of the air supplied to the air ring in this bearing also generates noise when the rotor rotates abnormally. A horn 5 is provided integrally. An auxiliary shaft 6 is added to the end of the rotor shaft to make it integral. This auxiliary ball 6 has an air hole 6a passing through it along its longitudinal axis, and this air hole 6a.
Air inflow holes 6c, 6c are provided on the outer peripheral surface of the shaft from a, and a maxim 6b is provided protruding from the outer peripheral surface of the shaft. A cylindrical ball holder 7 with a cap 7a at the tip is inserted into this auxiliary shaft 6, and one or more balls 8 are interposed between the inner surface of the cap of the ball holder 7 and the gold inspector 6b of the auxiliary shaft. urge That is, the pole 8 is sandwiched between the collar portion 6b and the umbrella portion 7a. The side surface of the umbrella portion 7a that comes into contact with the ball is a tapered surface with the inner circumference side depressed so that the outer circumference side is closer to the flange side than the inner circumference side. In this state, as shown in the upper half above the line X-X in Figure 2, the air hole perforated in the auxiliary shaft is The inflow holes 6c, 6c are all closed by the inner surface of the ball presser 7. This ball holder 7 is always pressed with a constant pressure toward the auxiliary shaft by a spring 9 interposed between the ball holder 7 and a governor shaft 11a which is connected to the tip of the auxiliary shaft. High-pressure air for rotating the rotor is introduced into the governor chamber R inside the main body through the main valve from an air inlet hole provided at one end or any position of the main body 1, passes through the outer periphery of a safety device consisting of an auxiliary shaft, a ball retainer, etc., and then enters the cylinder. The air is led to the cylinder chamber through a supply hole that closes to the chamber S, and rotates the rotor.

Between the air supply hole H closed to the cylinder chamber and the governor chamber R, there is a hole 1 having an inner diameter that allows the above-mentioned ball 8 to be inserted sufficiently.
0 is punched. Operation Next, the operation of the safety device constructed as described above will be explained.

The air now led to the governor chamber passes through the hole 10 and the air supply hole, and is then supplied to the cylinder chamber, causing the rotor to rotate.

If the supplied air pressure is at or below the set pressure, the rotor will rotate normally, but if the supplied air pressure exceeds the set pressure, or if water is introduced, etc., and the rotor exceeds the set maximum rotation speed, the governor A governor 11 provided on the shaft operates to control the amount of air supplied and reduce the rotational speed of the rotor. However, if this governor becomes rusty due to moisture that has entered with the working air, or does not operate properly due to foreign matter that has entered, the governor will rotate at a high speed that far exceeds the set maximum rotation speed. At this time, centrifugal force acts on the ball 8 due to the pressing force of the spring 9, which overcomes the force of the ball holder 7 and the spring pressure, and this centrifugal force pushes the ball holder back and protrudes in the direction of its outer circumference. work like that.

This is because when the rotor rotates normally, the ball holder is pressed against the auxiliary shaft side by the spring 9, and the ball does not jump out toward the outer circumference, but when the set maximum rotation speed is reached, the pressing force of this spring becomes greater. The centrifugal force begins to hit the ball,
By retracting the ball holder, the ball moves toward the outer periphery as shown in the lower half of FIG. As a result, the air inflow hole 6c is opened to the air supply hole, and a portion of the air is introduced into the horn 5 through the air supply hole 6a, causing the horn to sound to notify the operator of an abnormality. As the rotational speed of the rotor further increases, the ball 8 completely pops out from the ball clamping position, that is, the flange of the auxiliary shaft and the umbrella of the ball holder, as shown in the upper half of Fig. 1
0 and closes the air supply hole, which has a diameter slightly smaller than this hole 10, cutting off the air supply into the cylinder and stopping the rotation of the rotor, but air is also supplied to the horn side and the whistle sounds. There is. When making a quick stop with a grinder, etc., if there is a danger, do not completely block the air supply hole H with a ball, but close it slightly so that the rotor rotates at a low speed that can be safely stopped. control. In this case as well, the ball presser 7 is moved by the spring 9 to the collar 6b.
The air inflow hole 6c is brought into contact with the air supply hole H',
Similarly to the above, air is allowed to flow into the horn 5, and the horn 5 is sounded. In order to stop the operation of this safety device, the main body 1 must be disassembled.

Effects of the Invention According to the present invention, when the ball held between the auxiliary ratchet provided on the rotor shaft and the ball holder facing it reaches a rotational speed higher than the set drum height rotational speed of the rotor, this Due to the centrifugal force acting on the ball, it overcomes the spring pressing force and pops out from its clamping position, and when the ball holder is moved, the air supply hole leading to the horn, which was closed by the ball holder, is opened and the air supply hole leading to the rotor is opened. By allowing the air to flow through the rotor chamber, a portion of the air supplied to the rotor chamber is supplied to the horn and activates the horn, allowing the operator to quickly detect abnormalities and rotating at even higher speeds, causing the ball to move away from the pinched position. The rotor stops because the escape hole is completely closed and the air supply to the rotor chamber is cut off.

Also, air is supplied to the horn at this time, so the horn will sound, and even after the rotor has reached the maximum rotation set in this way and the safety device is activated and the rotor is stopped, the horn will still sound. If the tool stops due to the action of a safety device, or if the tool stops without sounding the horn, the operator may
It has the advantage that it is easy to identify whether the stoppage is due to a failure of the reduction gear, rotor, etc., and also has the effect of enabling safer work.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view, Figures 2 and 3 are sectional views of the figure,
This shows an explanation of the operation at the time of abnormal rotation. 1...Body, 2...Rotor, 3...
...Power transmission mechanism, 4...Bearing, 5...Honk horn, 6...Auxiliary shaft, 6a...Air hole,
6b... collar part, 6c... air inflow hole,
7...Ball holder, 7a...Umbrella part, 8...Ball,
9... Spring, 10... Hole, 11... Governor, S... Cylinder chamber, R... Governor chamber, H... Air supply hole. Figure 2 Figure 3

Claims (1)

[Claims] 1. A rotor shaft that rotates by supplying high-pressure air in an air tool that is equipped with a governor that adjusts the rotation of the rotor and a safety device that cuts off the air supply to the rotor and stops the rotor when it reaches a set maximum rotation speed. an auxiliary shaft with a flange connected concentrically with the auxiliary shaft at the end;
In addition, a ball holder equipped with a cap with a recessed inner circumferential side, and a ball held between the cap of the ball holder and the flange of the auxiliary shaft.
An air inflow hole that is made up of a spring that presses the ball holder toward the flange side to hold the ball elastically, and a horn provided on a part of the main body, and that opens and closes into the governor chamber when the ball holder slides, and this air. An air hole that communicates with the inflow hole and connects to the horn is drilled in the auxiliary shaft, and is communicated with the governor chamber through the air supply hole that leads to the cylinder chamber, so that if the governor malfunctions, the rotor will not rotate at the set rotation speed. This safety device for an air tool is characterized in that when the ball reaches a high speed, the centrifugal force acting on the ball supplies air to a horn, issues an alarm, and cuts off the air supply to the rotor to stop the air tool.