JPH0719706Y2 - Blade protection mechanism for polishing machine - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a polishing machine equipped with a mechanism for automatically reciprocating a tool post by an electric motor, and when the automatic feed of the tool post stops due to some trouble, it rotates. The present invention relates to a mechanism for protecting a cutting tool from a whetstone inside.

[Conventional technology]

In the conventional polishing machine, the motor for rotating the grindstone and the power source for the reversible motor for moving the tool rest are separate from each other, and they are started and stopped by operating respective independent power switches.

[Problems to be solved by the invention] In this method, when the reversible motor falls into a restrained state due to a mechanical problem or the like and stops rotating during the polishing work, the movement of the tool rest stops, but the grinding stone The drive motor, i.e. the grindstone, remains rotating. Therefore, since a part of the tool fixed to the tool rest continues to be polished, there is a problem that the tool in that part is burned and the accuracy of the tool is significantly reduced.

The present invention solves the above-mentioned problems of the prior art and protects the cutting tool from the rotating grindstone even if the reversible motor for moving the tool rest falls into a restrained state due to mechanical failure etc. Is to prevent burnout and deterioration of accuracy.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention provides a detector for restricting the range of reciprocating movement of a tool post, and a forward / reverse switching means for switching the direction of rotation of a reversible motor to normal rotation or reverse rotation according to a signal from the detector. A rotation detecting means for emitting an electric signal according to the rotation speed of the reversible motor, a judgment circuit for judging the rotation speed by receiving a signal from the rotation detecting means, and the grindstone driving electric motor according to the signal of the judgment circuit. Is provided with an output means for starting and stopping, and a timer circuit for compensating the determination circuit for a certain period of time when the rotation direction of the reversible motor is switched by receiving a signal from the detector. When the signal cycle exceeds a certain time, the power source of the grindstone driving electric motor is shut off by a signal output from the output means via the determination circuit.

[Action]

If the electric motor for the turret falls into the restrained state during the polishing and the rotation stops and the movement of the turret stops, the judgment circuit judges that the cycle of the electric signal output from the rotation detection means is a certain time or more. Then, a signal is output from the determination circuit to the output means, and further, a signal from the output means is output to stop the rotation of the grindstone rotating electric motor and stop the rotation of the grindstone.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a right side view of the blade polishing machine, FIG. 2 is a front view of FIG. 1, and a block circuit diagram of FIG.

In the figure, a reversible electric motor 1 for moving a tool rest (hereinafter referred to as a tool rest electric motor 1) reciprocates a tool rest 6 for fixing a tool 5 by a transmission means composed of a pinion 3 and a rack 4 via a speed reducer 2. It is movably mounted on a base 7 having a rail. Detection pieces 8 and 9 provided on the left and right of the tool post 6, respectively
Activating a pair of left end detection sensor 10 and right end detection sensor 11 composed of micro switches and the like arranged at the left end and the right end of the base 7 to detect the reversal position during reciprocating movement of the tool rest 6, and the reversible motor 1 The rotation direction of can be switched between normal rotation and reverse rotation. The detectors that regulate the reciprocating range of the tool rest 6 are the detection pieces 8 and 9, the left end detection sensor 10, and the right end detection sensor 11.
It is composed of. A grindstone 13 facing the tool rest 6 is provided in the upper rear part of the base 7, and the grindstone 13 is rotationally driven by an electric motor 12 for driving the grindstone (hereinafter, referred to as electric motor 12 for grindstone).

As shown in the block circuit diagram of FIG. 3, the turret motor 1 is connected to the power source through the normally open contacts 14a, 15a and the phase advancing capacitor 17, and is normally rotated by opening and closing the normally open contacts 14a, 15a. It is reversed.

When the normally open contact 14a is closed, the tool rest motor 1 rotates in the forward direction, and the tool rest 6 moves leftward until the detection piece 8 contacts the left end detection sensor 10. When the detection piece 8 reaches the position of the left end detection sensor 10, the left end detection sensor 10 operates and the normally open contact is made.
14a is opened, then the normally open contact 15a is closed, the direction of rotation of the tool rest motor 1 is switched from forward to reverse, and the tool rest 6 is rotated.
Moves to the right until the detector 9 contacts the right end detection sensor 11. When the detection piece 9 reaches the position of the right end detection sensor 11, the normally open contact 15a is opened, and then the normally open contact 14a is closed again, and the rotation direction of the tool rest motor 1 is switched from reverse rotation to forward rotation. The tool rest 6 moves from the direction to the left.

The series of reciprocating operations of the tool rest 6 and the rotation of the grindstone 13 polish the tool 5 held by the tool rest 6.

When the turret motor 1 falls into a restrained state during the polishing and the rotation stops, and the movement of the turret 6 stops, the rotation of the turret motor 1 is constantly detected so that the tool 5 is not burned.
Immediately, the grindstone electric motor 12 is stopped, and the rotation of the grindstone 13 is stopped.

The operation procedure will be described with reference to the block circuit diagram of FIG. 3 and the time chart diagram of FIG. Here, a in FIG.
The signals in the portions indicated by-n are (a)-
This corresponds to the time chart shown in (n).

First, when the operation switch 19 is operated, the logic "0" changes to "1" as shown in FIG. Detecting the rise of this logic, the timer 27 keeps for a preset time t ₁ .
Issue a logic "1" pulse. This pulse of logic "1" excites the relay coil 16 via the OR gate 28 and the AND gate 29, which serve as output means, closes the normally open contact 16a, and rotates the grindstone electric motor 12.

On the other hand, with respect to the electric tool 1 for the tool post, when the 0 side output of the flip-flop 21 serving as the forward / reverse switching means is the logic "1", the AND gate 22 (here, the AND gate 22 is the logic "1"). Via the relay coil 14, the normally open contact 14a is closed and the tool rest motor 1 is rotated to move the tool rest 6 to the left. The normal time until the turret motor 1 starts to rotate is the time set by the timer 27.
The relationship is smaller than t ₁ .

Therefore, when the tool rest motor 1 starts to rotate within the time t _{1, the} rotation detecting sensor 18 serving as the rotation detecting means outputs a pulse signal having a constant cycle as shown in FIG. 4 (j). The period of the pulse signal is T, when the time set in advance by the retriggerable timer 25 to be determining circuit for determining the rotational speed by checking the period T was set to t _2, when T <t _2, retrigger the output of Burutaima 25, FIG. 4 logic "1" as shown in (k), and the time T> t _2, the output of the retriggerable timer 25 is set to be logic "0".
In this embodiment, t _{2 of the} retriggerable timer 25 is
Is set to be slightly longer than the period T.

When the tool rest 6 reaches from the right end to the left end, the left end detection sensor 10 becomes logic "1" as shown in FIG. 4 (c), and the logic "shown in FIG. 4 (e) via the OR gate 20. The output of the flip-flop 21 is switched as shown in FIG. 4 (f) by the inverted output from "0" to "1", and the timer is
As shown in FIG. 4 (g), 24 is operated and t ₃
During, and outputs a logic "0", during this time t _3, the output is a logic "1" in the Andogedo 23 as shown in FIG. 4 (i)
Delay becoming. That is, closing of the normally open contact 15a of the tool rest motor 1 is delayed for t ₃ to eliminate impact when the tool rest motor 1 reverses from normal rotation to allow smooth rotation.

After the left end detection sensor 10 is activated and the power is cut off for the time t ₃ , the electric tool motor 1 for the tool post is reversed, so that the cycle T of the pulse signal of the rotation detection sensor 18 becomes T> t ₃ and retrigger. the output of Burutaima 25, as shown in FIG. 4 (k), for a time t _4, becomes logic "0". However, at the rising of the logic "0" to "1" of the output signal (e) of the left end detection sensor 10 via the OR gate 20, the timer 26 which is the timer circuit for compensating the judgment circuit is operated for a certain time. , For a preset time t ₅ (t ₅ > t ₄ ), a logic “1” is output as shown in FIG. 4 (l). This time
The signal of logic "1" t _5, the output signal of the fourth diagram of OR gate 28 and AND gate 29 (m), the Niu logic "1" is maintained as shown, the tool rest for motor 1 (n) Even at the time of reversal, the normally open contact 16a is kept biased, and the grindstone electric motor 12 remains rotating.

When the output of the AND gate 23 becomes logic "1", the relay coil 15 is excited, the normally open contact 15a is closed, the electric motor 1 for the tool post is reversed, and the tool post 6 is moved to the right. When the tool rest 6 reaches the right end from the left and the detection piece 9 comes into contact with the right end detection sensor 11, the right end detection sensor 11 becomes a logic "1" as shown in FIG. the inverted output from the logic "0" shown in FIG. 4 (e) to "1" with switches to indicate output of the flip-flop 21 in FIG. 4 (f), also for a predetermined time t ₃ in the timer 24, outputs a logic "0", during this time t _3, the output is a logic "1" of the aND gate 22 as shown in FIG. 4 (h)
Delay becoming.

Further, as in the case of detecting the left end, the right end detection sensor 11 is activated, and the electric power for the turret motor 1 is cut off during the time t ₃ ,
The output of the retriggerable timer 25 during the time t _4, during time t ₅ in becomes a logic "0" the timer 26, the logic signal of the OR gate 28 and AND gate 29 outputs a logic "1", " Keep 1 ".

If the turret motor 1 falls into a restrained state and stops rotating due to some trouble, the cycle T of the pulse signal output from the rotation detection sensor 18 becomes T> t ₂ , so that the output of the retriggerable timer 25 becomes the first value. As shown in FIG. 4 (k), it becomes a logic "0". On the other hand, at this time, since the outputs of the timers 26 and 27 are logic "0" as shown in FIGS. 4 (b) and (l), the output signal of the OR gate 28 is shown in FIG. 4 (m), FIG. 4 (n) of the output signal of the AND gate 29 is logical "0".
The relay coil 16 is no longer excited and the normally open contact 16
A is opened and the rotation of the grindstone electric motor 12 is stopped.

[Effect of device]

According to the present invention, the rotation detection means of the reversible motor that reciprocates the tool rest and the output signal thereof detect the rotation speed of the reversible motor while compensating the rotation speed change at the time of reversal with the timer circuit, and the determination circuit. Through the output means, the electric connection was made so that the power supply of the grinding wheel drive motor could be cut off, so when the reversible motor falls into the restrained state, the power supply of the grinding wheel drive motor is immediately cut off and the grinding wheel is stopped. It is possible to prevent the cutlery of the turret from burning.

[Brief description of drawings]

FIG. 1 is a right side view of a polishing machine showing an embodiment of the present invention,
2 is a front view of FIG. 1, FIG. 3 is a block circuit diagram, and FIG. 4 is a time chart diagram corresponding to a to n in FIG. 1 is a turret motor, 5 is a turret, 6 is a turret, 8 is a detection piece, 10 is a left end detection sensor, 11 is a right end detection sensor, 12 is a grindstone electric motor, 13 is a grindstone, 14, 15, 16 Is a relay coil, 14
a, 15a, 16a are normally open contacts, 17 is a phase advancing capacitor, 18 is a rotation detection sensor, 19 is an operation switch, 20 and 28 are OR gates, 2
1 is a flip-flop, 22,23,29 are AND gates, 24,2
6 and 27 are timers, and 25 is a retriggerable timer.

Claims (1)

[Scope of utility model registration request] 1. A base for holding a tool on a base is provided reciprocally by a reversible electric motor, and a grindstone is rotatably driven by the electric motor on the base, and the tool rest is reciprocated while the tool and the grindstone are in contact with each other. In a polishing machine for performing required polishing, a detector for controlling the range of reciprocation of the tool rest, a forward / reverse switching means for switching the rotation direction of the reversible motor to normal rotation or reverse rotation by a signal from the detector, A rotation detecting means for emitting an electric signal according to the rotation speed of the reversible motor, a judgment circuit for judging the rotation speed by receiving a signal from the rotation detecting means, and starting the grindstone driving electric motor by the signal of the judgment circuit, An output means for stopping and a timer circuit for compensating the judgment circuit for a fixed time when the rotation direction of the reversible motor is switched by receiving a signal from the detector are provided, and the rotation detection hand is provided. When the period of the signal is equal to or more than a predetermined time, tool protection mechanism in the polishing machine is characterized in that the power is turned off the grinding wheel driving motor by a signal issued from the output means via the judging circuit.