JPH0351124Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a device for detecting the upper and lower limits of a cutting head in a tenon removal machine.

[Background of the idea]

Conventionally, as an upper and lower limit detection device for a mortising machine, there is, for example, Japanese Utility Model Publication No. 14973/1983.

The prior art will be explained using FIG. 6.

The convex portions 12a and 12b of the limit bar 12 vertically disposed from the bridge 5 correspond to the upper and lower limit detection switches 6 and 7 of the cutting head 3, and when the lower limit position is detected, the lifting motor 4 is reversed at the same time as the lower limit is stopped. The structure is such that it stops when the upper limit position is detected.

According to this structure, the limit bar 12 vertically disposed on the bridge 5 becomes very long and is easily subjected to external forces such as being hit by wood chips discharged during the tenoning operation, resulting in many troubles due to deformation.

Since this detection switch uses a limit switch with an actuator, there have been problems such as malfunctions caused by chips during long-term use.

Further, the cutting head 3, which has a mass of 60 to 80 kg, descends at a fast speed of about 6 m/min when cutting the material. When the cutting head 3 reaches the lower limit position, the lower limit detection switch 7 is activated and its contacts are switched to de-energize the lower switch and energize the lower switch.

However, because it was raised immediately after it had stopped descending, an excessive impact was applied to the main body. Furthermore, when the cutting head is raised and reaches the upper limit position, the upper limit detection switch 6 is activated and its contact is switched to deenergize the lifting switch. At this time, since the power supply is cut off while the inertia force of the ascent remains, there is a risk that the cutting head 3 will further rise and hit the lower part of the bridge 5, so there is a problem that the rising speed cannot be increased.

[Purpose of invention]

The purpose of this invention is to improve the reliability of the detector, protect the machine body, and improve work efficiency.

[Summary of the idea]

The present invention has a non-contact type switch and a rod that are not affected even if chips or the like adhere to the detector in the same member, and is devised to prevent the detection part from being exposed to the outside. The control circuit for the lifting motor is equipped with a timer circuit, and the timer circuit controls the forward and reverse rotation of the lifting motor in order to reduce the inertial force of lifting and lowering the cutting head.

[Example of idea]

An embodiment of the present invention will be described with reference to FIGS. 1 to 5.

FIG. 1 shows a side view of the mortising machine, showing the upper and lower limit detectors in an open state. Figure 2 is the first
FIG. 2 is an elevational view showing the positional relationship of upper and lower limit detection sections as viewed from the direction of arrow A in the figure. FIG. 3 is a side view showing the positional relationship of the upper limit detector among the upper and lower limit detectors.

In the figure, 1 is the base. Two guide bars 2 are hung in parallel on one side of the upper surface of the base 1, and the guide bars 2 are supported by a bridge 5 extending over the upper end of the guide bars 2. A cutting head 3 that is driven up and down by a lifting motor 4 is disposed on the guide bar 2 with the guide bar 2 as a guide. A saw is provided. On the other side of the base 1 is a vise 26 for fixing the wood.
is provided, and as the cutting head 3 moves downward, the circular saw descends to tenon the wood 27 fixed to the vise 26. On the side portions of the cutting head 3, there are rods 8a and 8b that are vertically slidably supported, and rods 8a and 8b that are interposed between the cutting head 3 and the rods 8a and 8b.
The detection device is composed of springs 10, 10, which are elastic members that always urge a, 8b toward the outside of the cutting head 3, respectively, and detectors 6, 7, which are activated by detecting the tips of the rods 8a, 8b. The devices are arranged one above the other relative to each other.

Further, a protrusion 5a is formed on the lower part of the bridge 5 to abut the end of the rod 8b that is biased toward the bridge 5, and a protrusion 5a that abuts the end of the rod 8a that is biased toward the base 1 is formed on the upper part of the base 1. A portion 1a is formed.

Therefore, when the cutting head 3 reaches the upper limit position, the protrusion 5a pushes the rod 8b downward, and the tip of the rod 8b is detected by the detector 7. When the cutting head 3 reaches the lower limit position, the protrusion 1a pushes the rod 8b downward. The rod 8a is pushed up and the tip of the rod 8a is detected by the detector 6.

Next, the control operation of the tenon removing machine will be explained using the block circuit diagram shown in FIG. 4 and the time chart shown in FIG. 5.

Signals a to i in the block diagram correspond to a to i in the time chart.

This block circuit diagram is operated by electric signals from the operation switch 13 and the detectors 6 and 7, and controls the operation and stopping of the lifting motor 4 and the circular saw drive motor 9.

A normally open relay contact 23a is connected to the power line of the circular saw driving motor 9, and normally open relay contacts 24a and 25a are connected to the power line of the lifting motor 4. The electrical connection and mechanical structure are such that when the normally open relay contact 24a is closed, the lifting motor 4 is reversed and the cutting head 3 is raised.

Relay coils of these normally open contacts 23a, 24a, 25a correspond to 23, 24, 25, respectively.

To start the tenon removal work, turn on the operation switch 1.
When Q3 is operated, its output a becomes logic "1", flip-flop 14 is set, and Q output d changes from logic "0" to "1". In response to this logic "1" signal, the relay coil 23 is excited via the amplifier 15, while the OR gate 16,
Relay coil 24 is excited via amplifier 17 . Therefore, the normally open relay contacts 23a and 24a are closed, and power is supplied to the lifting motor 4 and the circular saw driving motor 9. In other words, the circular saw rotates,
The cutting head 3 will be lowered.

When the cutting head 3 descends and reaches the lower limit position, the protrusion 1a of the base 1 pushes up the rod 8a, activating the detector 6, and its output b is reversed from logic "0" to "1". . Therefore, the flip-flop 14 is reset, the Q output d is inverted from logic "1" to "0", and the relay coil 2 is output via the amplifier 15, the OR gate 16, and the amplifier 17.
3 and 24 are demagnetized, normally open relay contacts 23a and 2
4a is opened, and the power to the lifting motor 4 and circular saw driving motor 9 is cut off. On the other hand, upon sensing the fall of the Q output signal d of the flip-flop 14, the timer 18 is activated and emits a pulse e having a preset time width _T1 . In response to this pulse signal e of time width _T1 , the flip-flop 19 is set,
The Q output f is inverted from logic "0" to logic "1", the relay coil 25 is energized via the amplifier 20, the normally open relay contact 25a is closed, and the lifting motor 4 is reversed.

This time T ₁ is a reversal pause time, and during this time T ₁ the cutting head ₃ continues to descend due to inertia even after reaching the lower limit. , the inertia force of the descent is reduced by frictional resistance, and then it can be raised, reducing the impact when reversing. Note that the time _T1 is set to about 0.2 seconds because if it is about 0.5 to 1 second, there is a risk that the cutting head 3 will hit the upper part of the base 1.

When the cutting head 3 returns quickly (9 to 12 m/min) and ascends to the upper limit position, the protrusion 5a of the bridge 5
, the rod 8b is pushed down and the detector 7
operates, and its output c is inverted from logic "0" to "1".

Therefore, the flip-flop 19 is reset, and the Q output f is inverted from logic "1" to "0".
The relay coil 25 is demagnetized via the amplifier 20, the normally open relay contact 25a is opened, and the power to the lifting motor 4 is cut off. On the other hand, upon sensing the fall of the Q output signal f of the flip-flop 19, the timer 21 is activated and generates a pulse g having a preset time width _T2 . In response to this pulse g with a time width T ₂ , the timer 22 is activated, and a preset time width T ₃ is activated.
The logic "1" pulse h is emitted, and the OR gate 1
6. Via the amplifier 17, the relay coil 24 is energized, the normally open relay contact 24a is closed for a time _T3 , the lifting motor 4 is rotated in the normal direction, and the cutting head 3 is lowered by an inch and then stopped.

Therefore, this time T ₂ is the reversal time at the upper limit, and during this time T ₂ the cutting head 3 continues to rise due to inertia even after reaching _the upper limit position. By providing this, the inertia force of quick return and rise can be reduced by frictional resistance.
After this, the cutting head 3 is lowered for a short period of time _T3 to offset the inertial force, reduce the impact at the time of reversal, and stop the cutting head 3.

If the time _T2 is about 0.5 to 1 second, there is a risk that the cutting head 3 will hit the lower part of the bridge 5, so it is set to about 0.2 seconds. If the time _T3 is too large, the descending head 3 will fall too far from the upper limit position, so it is set to about 0.3 to 0.5 seconds.

By appropriately setting these times T ₁ , T ₂ , and T ₃ , it becomes an effective means for minimizing the vertical dimension of the main body.

In the above embodiment, the upper and lower limit detectors are installed in the cutting head 3, but the upper limit detector is installed in the bridge 5.
Similar effects can also be obtained by disposing a lower limit detector on the base 1.

[Effect of idea]

In this invention, when the cutting head reaches the lower limit position and ascends, the power is cut off for a certain period of time and then the cutting head is raised, and when the cutting head reaches the upper limit position and stops, the power is cut off and then the lifting motor By reversing the cutting head, the inertial force in the direction in which it is moving is stopped and the cutting head is stopped, reducing the excessive impact applied to the main body. The workability can be improved.

Further, since the detection section for detecting the upper and lower limits is provided within the cutting head, there is no trouble caused by external forces and the detector operates reliably, so that reliability can be improved.

[Brief explanation of drawings]

Fig. 1 is a side view of a mortising machine showing the present invention, Fig. 2 is an elevational view showing the positional relationship of the upper and lower limit detection sections as seen from the direction of arrow A in Fig. 1, and Fig. 3 is an upper and lower limit detection section. 4 is a side view showing the positional relationship of the upper limit detection section;
5 is a block circuit diagram, FIG. 5 is a time chart, and FIG. 6 is a side view showing the prior art. In the figure, 1 is the base, 2 is the guide bar, 3
1 is a cutting head, 4 is a lifting motor, 6 and 7 are detectors, 8a and 8b are rods, 9 is a circular saw drive motor, 14 and 19 are flip-flops, 15 and 1
7, 20 are amplifiers, 16 are OR gates, 18, 2
1 and 22 are timers, 23, 24, and 25 are relay coils, and 23a, 24a, and 25a are normally open relay contacts.

Claims (1)

[Claims for Utility Model Registration] A tenoning machine comprising a cutting head that is driven up and down using a guide bar set upright on a base as a guide, and in which the upper end of the guide bar is supported by a bridge member, wherein: Rods are mounted on the upper and lower parts of the cutting head, respectively, and are slidably supported in parallel to the vertical direction of the cutting head, and are constantly urged outward from the cutting head by an elastic member provided between the rod and the cutting head. A detector is provided at the inner end of each rod to detect the presence or absence of the inner end of the rod, and a detector is provided at the cutting head position corresponding to the outer end of each rod. An opening is formed so that one end can be pressed freely,
When the cutting head descends and reaches the lower limit position, the protrusion provided on the upper surface of the base enters the opening provided on the lower surface of the cutting head and activates the detector, which is installed on the cutting head. It constitutes a control means that cuts off the power to the motor for driving the circular saw and the motor for lifting and lowering the cutting head, and raises the cutting head after a certain period of time, and the cutting head rises and reaches the upper limit position. In this case, the protrusion provided on the lower surface of the bridge member enters the opening provided on the upper surface of the cutting head to activate the detector, cut off the power to the lifting motor, and after a certain period of time, the An upper and lower limit detection device for a mortising machine, comprising a control means for turning on and reversing the power.