JPS6022163B2 - New machine tool safety device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a safety device for preventing abnormal high-speed rotation of pneumatic tools such as air grinders, sanders, drills, etc. exceeding a set maximum rotation speed.

Conventional technology and its problems In general, pneumatic tools such as air grinders and air sanders that obtain rotational energy from high-pressure air to perform various tasks are designed to rotate at high speeds within their safe tolerances. For safety reasons, it is mandatory to install a speed governor.

However, the high pressure air supplied to the pneumatic tool is not necessarily clean air at the pressure set for the tool. Sometimes high-pressure air higher than the set pressure is supplied, or water droplets are mixed into the air, and these water droplets act as lubricating oil. In such a case, the rotor rotates at a rotation speed higher than the safe maximum rotation set based on the characteristics of the pneumatic coolant.

To prevent this, the rotor shaft is equipped with a speed-governing mechanism, but the speed-governing mechanism (governor device) has rusted due to the water being supplied with the air, and as a result it does not work properly and the rotor is damaged. There is a risk of causing abnormally high speed rotation exceeding the set maximum rotation speed, which may damage the rotor or damage the scales.Furthermore, in the case of air grinders, the abnormally high speed rotation may cause the grinding wheel to undergo extreme D force. It may explode and become extremely dangerous. In order to keep the pneumatic tool safe even in such cases, a device equipped with a speed rotation prevention device that is activated when it rotates at a speed exceeding the set maximum rotation speed, in addition to the speed regulating mechanism, such as Tokkoku Sho 51-50080. Publication is proposed. However, in this device, a ball (ball valve) is competitively held by an elastic plate pressed against the outer periphery of the governor body protruding from the top of the rigid rotor shaft, and when the rotation speed exceeds the set rotation speed, this elastic plate Overcoming the pressing force and using the centrifugal force to protrude from the governor body, the second control boat is formed on the outer periphery of the governor body and connects the governor chamber and motor chamber, and is then inserted into the second control boat, which connects the governor chamber and the motor chamber. This is a safety device that shuts off the air and stops the motor.For this reason, the means for detecting abnormal rotation and the means for shutting off air are performed by the same ball valve, so the inside of the casing that forms the governor chamber is In addition, after the safety device is activated, the ball (ball valve) filled with iron inside the boat cannot be removed without dismantling all parts when resetting it, and the ball cannot be removed from the governor body, which rotates at high speed. The valve tries to pop out due to the centrifugal force, but since the ball valve cannot safely pop out inside the swinging path, the ball valve is pushed against the inner peripheral surface of the swinging path by the strong pressing force of the far D force. ``If it rotates further in this state, that is, if it rotates with half of it protruding, the second control boat will not be loaded with iron, and the motor will be damaged.'' rotation, and the safety deactivation is inaccurate.
Also, since there is only one ball valve, the balance is poor and vibrations may occur. Furthermore, it has the disadvantage that it cannot be applied unless it is of a vertical type, with the rotor shaft and governor body being perpendicular to each other. Means for Solving the Problems In view of this, the present invention provides a speed mechanism at the end of the rotor shaft of the pneumatic cooler on the air supply side to rotate within the maximum setting range, and also detects abnormalities in this speed governing mechanism. In the pneumatic system, which is equipped with a safety device that stops the rotor when it rotates above the set maximum rotation speed, the rotor shaft is supported and an air supply hole is provided to provide continuity between the rotor chamber and the speed control chamber. A bearing with a hole is inserted into the outer periphery of the bearing so as to be rotatable and slidable, and a collar facing and closing the air supply hole is provided on the outer periphery. a valve having a large groove formed on its outer periphery; a flanged inner cylinder which is inserted into the valve and has grooves on the flange and a recess for ball formation on the outer periphery of the inner cylinder; This poison-damaged inner cylinder is iron-coupled with a small hollow in the valve, and when the rotor rotates above the set maximum rotational speed, the centrifugal force that acts causes the valve to pop out from the hollow and be stored in the notch via the groove. It consists of a ball that constantly presses the valve toward the bearing side and a spring that is interposed between the valve and the golden part of the governor shaft.When the rotor reaches a set maximum rotation speed or more, the ball is Due to the action of the far D force that overcomes this, the groove of the inner cylinder with a flange is used as a guide to pop out from the state where the inner cylinder with a flange and the recess of the valve are aligned, and the iron is inserted into the notch of the inner cylinder with a flange. The spring pressure applied to the valve is released from the supporting force of the inner cylinder through the ball, and the action of the spring causes the valve to slide toward the bearing side, closing the air supply hole and cutting off air to the rotor chamber for control. Provides pneumatic safety equipment.

Example The present invention will be explained below based on embodiments shown in the drawings.

FIG. 1A is a partially cutaway front view of the pneumatic cooler, FIG. 1B is an enlarged sectional view of the safety device, and FIG. 2 is an exploded perspective view of the main parts. In the figure, 1 is the main body of the pneumatic tool. A rotor 2 is inserted overboard into the cylinder of the main body 1, and the end of the rotor 2 is supported rotatably through a bearing 4. The rotational force of 2 is transmitted directly or at a reduced speed to a grindstone drill or the like via a power transmission mechanism or the like.

Further, a bearing, metal, etc. B is interposed between the rotor shaft 2a of the rotor 2 and the bearing so that the rotor shaft can be smoothly laid. A metal part 4a is provided on the outer periphery of this bearing 4, and an air supply hole A is bored in a part of this metal part 4a for supplying air into the main body cylinder, and the part protrudes from the side surface of this bearing 4, and inside. A valve 5 is installed on the outer periphery of a short guard 4b holding a bearing B so as to be rotatable and slidable. This valve 5 has a short tubular shape with stepped different diameters, and a flange 5a is integrally provided on the outer periphery of the large diameter end surface, and the side surface of this metal 5a is made to face the air supply hole A drilled in the flange 4a of the bearing. When there is a gap C between the tip side of the flange and the flange 4a, this gap C
, so that air can be introduced smoothly into the rotor chamber through the air supply hole A, and when the valve 5 slides and closes due to the pressing force of springs 6 and 7, which will be described later, the gap C is formed on the side surface of the collar 5a of the valve. This closes the air supply hole A and stops or restricts the introduction of air into the rotor chamber.

A flanged inner cylinder 8 is iron-fitted to the inner surface of the small-diameter cylinder portion 5b on the other end side of the valve 5, and a speed regulating mechanism G
A governor shaft 9 having a diameter is inserted into the shaft, and the tip of the shaft 9 is screwed onto the tip of the lower shaft 2a to form an integral unit.

At this time, springs (coil springs) 6, 7 are interposed between the flange 9a of the governor shaft 9 and the outer surface of the valve 5.
The valve 5 is pressed against the flange of the bearing with a pressing force of 7. These springs 6, 7 may be of one strip. A plurality of key grooves 8a are carved along the axial direction on the outer peripheral surface of the flanged inner cylinder 8, and key grooves 5c are formed along the axial direction on the inner peripheral surface of the small diameter cylindrical portion 5b of the valve, A key K is inserted between both key grooves 8a and 5c, and the valve 5 and the flanged inner cylinder 8 rotate together, but the key groove 5c provided on the valve 5 side is made longer than the length of the key K. This allows the valve to slide along this key. Also, the flange part 8 of the inner cylinder 8 with this maxim
A recess 8c is carved on the outer periphery of the vicinity of b to fit a part of the ball 11 for operating the safety device, and a groove 8d and a notch 8e are respectively provided on the side surface of the collar 8b by forming a groove 8c in the recess 8c. At positions on the inner surface of the valve facing the depressions 8c, grooves 8d, and notches 8e provided in the attached inner cylinder 8, a small depression 5d is provided on the inner circumference side, and a large depression 5e is provided on the outer circumference side.

This small depression 5d may be ring-shaped. In the safety device constructed as described above, the air supply boat 1 is connected to the main body of the pneumatic cooler by operating the main valve.
The high-pressure air supplied from the rotor 2 is guided into the rotor chamber through the speed control chamber R, the gap C between the flange of the valve 5 and the bearing, and the air supply port A, and the rotor 2 rotates at the required rotation speed.

When the rotor 2 reaches a set rotational speed or higher, the governor mechanism G operates, and the governor valve V facing the air supply boat operates.
moves back and forth to adjust the amount of air supplied to the low-speed chamber and regulate the speed. Normally, this speed regulating mechanism automatically controls the rotor so that it always rotates at or below the maximum allowable rotation speed. However, if the currently supplied air pressure is abnormally higher than the set pressure, or if the air contains moisture and this acts as a lubricant, causing the rotor to rotate at an abnormally high speed, the speed regulating mechanism If speed control becomes impossible, spring 6
, 7, the ball 11 for operating the safety device, which was supported under pressure between the recesses 5d and 8c of the valve and the bearing, is pushed into the recess 5d.
, 8c, an iron connection is made between the notch 8e in the outer circumferential direction and the valve recess 5e along the pop-out groove 8d by centrifugal force. Because the ball 11 is almost buried in the hollow 8e and the depression 5e, the space is larger than the diameter of the ball.
The valve 5 is pushed out by the amount that the ball li moves toward the rotor side by the pressing force of the springs 6 and 7. Therefore, the air supply □A provided on the side of the collar 5a of this valve 5 on the bearing side
The air supply to the rotor chamber is forcibly stopped, or the amount of air supply is reduced so that the rotor reaches a safe rotational speed or less, and the rotor is brought to a stopped or nearly stopped state or a safe rotating state, and the pneumatic cooling is performed. This is to prevent unexpected accidents due to abnormally high speed rotation of the motor. Effects of the Invention According to the present invention, a safety device is provided separately from the regulating mechanism normally provided in the pneumatic cooler, and even if this regulating mechanism does not operate normally, the When high-pressure air or water is supplied into the rotor chamber and the rotor reaches a high rotation speed exceeding the set maximum rotation speed, a ball supported between the valve and bearing is used to detect the abnormal rotation. The generated centrifugal force causes it to pop out from the joining position, and the pressure of the spring on the valve causes the air shutoff valve to slide toward the air supply hole.
This valve is designed to close the air supply hole, so even if the speed regulating mechanism does not operate normally due to a failure, etc., the rotor rotation will decelerate or stop before it exceeds the set maximum rotation. It can be used safely and the pole, which is a means of detecting abnormal rotation, only needs to protrude from the stereotactic layer in the recess, so it can be applied to both vertical and horizontal types without having to control the position of the tool, and can be used for detection. Since the means and the air shutoff means using a valve are provided separately, operation is reliable, and each part can be manufactured by machining, making it easy to assemble. Disassembly is also easy.

Furthermore, even if the safety device needs to be reset after activation, it has the advantage that it can be easily set by simply removing the case.

[Brief explanation of the drawing]

In FIG. 1A, the - portion was broken. A front view, FIG. 2B is an enlarged sectional view of the main part, and FIG. 2 is an exploded perspective view of the main part. 1 is the main body, 2 is the rotor, 2a is the rotor shaft, 4 is the bearing, 4a is the flange, 4b is the short section, 5 is the valve, 5a is the rusted part, 5b is the 4 diameter cylinder part, 5c is the keyway, 5d
5e is a recess, 6 and 7 are springs, G is a speed regulating mechanism, 8 is an inner cylinder with a metal clasp, 8a is a keyway, 8b is a flange, 8c is a recess, 8d is a groove, 8e is a notch, R is The speed chamber, C is the gap, 9 is the governor shaft, 9a is the collar, A is the air supply hole, and 11 is the pole. Figure 1 Figure 2

Claims (1)

[Claims] 1. A speed regulating mechanism is provided at the end of the rotor shaft on the air supply side to rotate within the maximum setting range, and a safety device is provided to stop the rotor when the speed regulating mechanism is abnormal and the rotor rotates beyond the set maximum rotation speed. A pneumatic tool is equipped with a bearing that supports the rotor shaft and is provided with an air supply hole that connects the rotor chamber and the speed regulating chamber, and a shaft that is rotatably and slidably mounted on the outer periphery of the short tube of this bearing. a valve that is fitted into the valve and has a collar on its outer periphery that faces and closes the air supply hole, a small depression inside and a large depression on the outer periphery of the valve; A flanged inner cylinder has a notch and a groove on the flange and a recess for fitting a ball on the outer periphery of the inner cylinder, and the flanged inner cylinder is fitted into the recess of the flanged inner cylinder and the small recess of the valve, and the rotation speed exceeds the set maximum rotation speed. When the rotor shaft rotates, the ball pops out from the recess and is stored in the notch through the groove, and the valve is constantly pressed toward the bearing side, and the ball is inserted between the valve and the flange of the governor shaft. It consists of an interposed spring, and when the rotor reaches a set maximum rotation speed or higher,
Due to the action of centrifugal force that overcomes the pressing force of the spring, the ball pops out from the fitted state in the recess of the flanged inner cylinder and valve using the groove of the flanged inner cylinder as a guide, and fits into the notch of the flanged inner cylinder. As a result, the spring pressure applied to the valve is released from the supporting force of the inner cylinder through the ball, and the action of the spring causes the valve to slide toward the bearing side, closing the air supply hole and cutting off air to the rotor chamber. A safety device for pneumatic tools that is controlled by