JPH047685B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a nozzle touch and a
Regarding the sprue break mechanism.

Prior Art The nozzle touch mechanism in conventional injection molding machines uses a hydraulic cylinder to press the nozzle against the mold using hydraulic pressure. Also, a nozzle touch mechanism has been developed in which the nozzle touch mechanism is driven by a motor without using hydraulic pressure.

Problems to be Solved by the Invention When the nozzle touch mechanism is driven by a motor, it is necessary to always press the nozzle against the mold with a constant pressure, so it is necessary to keep current flowing through the motor. The motor generates heat and energy loss occurs. Also, if you use a motor with a brake and press the nozzle against the mold at a constant pressure, then apply the brake and cut off the current to the motor, heat generation and energy loss in the motor can be improved, but Since the brakes are only applied, even if the motor shaft moves for some reason, the brakes will still be applied at that position.
There was a drawback that the nozzle could not always be pressed and held against the mold with a constant pressure.

Means for Solving the Problems The present invention provides a slidable slide base on which an injection device is placed so as to be able to slide within a certain range, a cam driver that is driven by a motor to move forward and backward, and the above-mentioned The cam driver provided on the slide base moves the injection device until the nozzle comes into contact with the mold as the cam driver moves forward, and when the nozzle comes into contact with the mold, it rotates and operates a brake device via the cam follower to fix the slide base. a first cam which is rotated by the backward movement of the cam driver to release the operation of the brake device, and a first cam which is provided on the slide base and which rotates by the forward movement of the cam driver to press the injection device via a spring. a second cam that presses the nozzle against the mold and rotates as the cam driver moves backward to release pressure contact between the nozzle and the mold; This is a nozzle touch/sprue break mechanism characterized by being provided with a moving protrusion.

Operation When the motor is driven and the cam driver is moved forward, the cam driver comes into contact with the first cam, advances the injection device via the first cam, and brings the nozzle into contact with the mold. When the nozzle comes into contact with the mold, the first cam rotates while pushing down the cam follower, operating the brake device and fixing the slide base. Next, the cam driver rotates the second cam to press the spring, and the force generated by the compression of the spring presses the nozzle against the mold. Also, when the motor is reversed and the cam driver is moved backward, the cam driver rotates the second cam to release the pressure contact between the nozzle and the mold, and then rotates the first cam to operate the brake device. The cam follower presses the protrusion provided on the slide base to move backward, and the injection device moves backward.

Embodiment The figure is a partially cutaway view showing an embodiment of the present invention. Reference numeral 1 denotes an injection device, which is fixed to an injection unit base 5. 2 is the cylinder, 3 is the nozzle, 4
is a mold. The injection unit base 5 is slidably mounted on a slide base 6, and the injection unit base 5 has a pressure plate 7 having a rotatably fixed roller R1. 5 and pressure plate 7
are connected by a spring 8. The slide base 6 has a first cam C1 and a second cam C2 that rotate around shafts 9 and 10 fixed to the slide base 6. It has rotatable rollers R3 and R4 that engage with the cam driver 11, respectively. A cam follower 12 having a roller R2 is pressed against the first cam C1 surface by a spring 13, and the cam follower 12 is pressed by the first cam C1.
When the link 14 of the cam follower 12 moves downward in the figure, the brake shoe of the brake device 15 is actuated to fix the slide base 6 and the guide rod 16. The first and second cams C1 and C2 have two stable stopping points as shown in the figure.
That is, the cam surface of the first cam C1 has concave portions at the position shown by the solid line and the position shown by the dotted line, and the radius around the shaft 9 at these positions is smaller than the periphery of that position. The first cam C1 is held in these two positions. Similarly, the radius of the second cam C2 becomes smaller than the surrounding area at the position indicated by the solid line and the position indicated by the dashed line in the drawing, and becomes a concave portion.
It is designed to be held by roller R1 at these two positions. The slide base 6 is fixed to the guide rod 16 through bushes to slidable tubes 17 and 18, and is also fixed to the housing of the brake device 15. Also,
A tube 19 is also slidably inserted into the guide rod 16 via a bush, and the tube 19 is fixed to the injection unit base 5. Reference numeral 20 denotes a protrusion that comes into contact with the cam driver 11 provided on the slide base 6. The cam driver 11 is a roller chain 2 that spans sprockets S1 to S4.
1, and when the roller chain 21 is driven by the motor M, the cam driver 11 engages with the rollers R3 and R4 of the first cam C1 and the second cam C2 and the projections. It's becoming like that. Note that 22 and 23 are engagement surfaces provided on the injection unit base 5 and the slide base 6. Further, LS1 to LS3 are limit switches that control the drive of the motor M.

Next, the operation of this embodiment will be explained.

First, to explain the process of advancing the injection device to perform the nozzle touch operation, the motor M
When the roller chain 21 is rotated counterclockwise in the figure, the cam driver 11 engages with the roller R3 of the first cam C1 and rotates the first cam C1 around the shaft 9. However, the roller R2 is pushing the first cam C1 due to the force of the spring 13 of the cam follower 12, and when it tries to rotate, the radius increases, so the first cam C1 does not rotate and the shaft 9 Slide the slide base 6 along the guide rod 16 to the left in the figure. Furthermore, since the second cam C2 presses the roller R1, the injection unit base 5 is also slid along the guide rod 16 via the roller R1, the pressure plate 7, and the spring 8, and the nozzle 3 is moved into the mold 4. move in the direction. As a result, when the nozzle 3 comes into contact with the mold and the forward movement of the injection device 1 and the injection unit base 5 (left side in the figure) stops, the spring 13 has a weaker force than the spring 8. First, the first cam C1 starts rotating around the shaft 9 while compressing the spring 13, pushes down the link 14 of the cam follower 12, and when the cam follower 12 overcomes the protrusion P1 on the cam surface and rotates slightly, the roller The engagement between R3 and the cam driver 11 is released. The point at which it crosses over the protrusion P1 is formed in a concave portion, and the radius of the first cam C1 is formed to increase thereafter, so that the first cam C1 is reversed by the force of the spring 13 of the cam follower 12. (clockwise in the figure) and is stopped and held at the position shown by the dotted line in the figure. On the other hand, at this point, the link 14 of the cam follower 12 is pushed down and the link 14 operates the brake shoe of the brake device 14, so that the slide base 6 is fixed to the guide rod 16 at this position. Next, when the cam driver 11 contacts the roller R4 of the second cam C2 and rotates the second cam C2, the second cam C2 presses the roller R1, and the pressure plate 7, The injection unit base 5 is pressed to the left in the figure via the spring 8, and the second cam C2 rotates, and at the point where the roller R1 rotates slightly from the position beyond the protrusion P2, the cam driver 11
However, like the first cam C1, this second cam C2 is also formed so that its radius increases from the point beyond the protrusion P2. The cam C2 is also reversed by the force of the spring 8, and is stably held at the position shown by the dotted line in the figure. At this time, the spring 8 is compressed, and the nozzle 3 comes into pressure contact with the mold 4 due to the repulsive force generated by the compression. The force that presses the nozzle 3 against the mold 4 is generated by the force accumulated in the spring 8, and by adjusting the radius of the cam surface of the second cam C2, the nozzle 3 and the mold 4 can be brought into contact with each other. The pressure contact force can be adjusted and maintained at a constant pressure contact force. When the cam driver 11 further moves to the left in the figure and presses the limit switch LS1, the drive of the motor M is stopped.

Next, the operation when removing the nozzle 3 from the mold 4 at the time of sprue break or nozzle replacement will be described.

When the motor M is reversed and the roller chain 21 is rotated clockwise in the figure, the cam driver 11 moves backward (to the right in the figure), and first, the second cam C2, which is stopped at the position indicated by the dashed line in the figure, moves backward. The second cam C2 contacts the roller R4 and moves backward while rotating the second cam C2 clockwise about the shaft 10. When the contact between the cam driver 11 and the roller R4 is released, the second cam C2 is reversed (counterclockwise) so that the roller R1 contacts the recess P4, which has the smallest radius in the vicinity. , is held at the position shown by the solid line in the figure. That is, the concave portion P4 on the cam surface has the smallest radius in its vicinity, and the cam surface is formed such that the radius gradually increases on both sides, so the cam driver 11 moves the second cam C2 along the solid line in the figure. Even if the roller R1 is rotated further clockwise than the position, the force of the spring 8 causes the roller R1 to rotate counterclockwise so that the recess P4 and the roller R1 are engaged, and are held at the solid line position in the figure. Next, when the cam driver 11 moves further backward, the cam driver 11 comes into contact with the roller R3 of the first cam C1 located at the dotted line position in the figure, and rotates the first cam C1 clockwise about the shaft 9. let Then, when the contact between the cam driver 11 and the first cam C1 is released, the first cam C1 is rotated counterclockwise by the spring 13 so that the roller R2 of the cam follower 12 comes into contact with the recess P2 whose radius has become smaller. The first cam C1 is held at the position shown by the solid line in the figure, and the operation of the brake device 15 is released. Then, the cam driver 11 comes into contact with the protrusion 20 provided on the slide base 6, and the slide base 6 is moved to the right in the figure by the cam driver 11, so that the engagement surface 23 of the slide base 6 and the injection unit base 5 are engaged. When the mating surfaces 22 come into contact, the cam driver 11 moves the injection unit 1, cylinder 2, and nozzle 3 to the right in the figure via the slide base 6 and the injection unit base 5, and the nozzle 3 and the mold 4 come into contact with each other. Solve. If the sprue breaks, the slide base 6 is the limit switch.
Step on LS2, and when limit switch LS2 turns ON, stop driving motor M and stop movement of injection device 1 and nozzle 3. When replacing nozzle 3, move further back from limit switch LS2 (to the right in the figure). limit switch installed in
When slide base 6 steps on LS3, motor M
All you have to do is stop it.

Note that instead of the engaging surfaces 22 and 23, the slide base 6 and the injection unit base may be connected by a link that is extendable and does not extend beyond a certain level. Furthermore, a balancer may be attached to the first cam and the second cam so that these cams are more stable at the solid line position and the dot-dashed line position in the figure.

Effects of the Invention In the present invention, a cam driver driven by a motor transports the injection device using the first cam until the nozzle touches the mold, and presses the nozzle against the mold using the second cam and spring. Since the force is applied, the force with which the nozzle contacts the mold is always constant, and the pressure force can also be adjusted to any value by adjusting the cam curve, or radius, of the second cam. . Furthermore, after the single-stage nozzle is pressed into contact with the mold, the drive of the motor can be stopped, resulting in less energy loss. Furthermore, since the first and second cams are simply driven by the cam driver, there is no need to precisely adjust the rotational position of the motor to adjust the nozzle contact force, and the limit switch can be used to adjust the rotational position of the motor to the appropriate position. Since it can be stopped, controlling the nozzle touch is also very simple and easy to control.

[Brief explanation of drawings]

The figure is a partially cutaway view of an embodiment of the present invention. 1... Injection device, 3... Nozzle, 4... Mold,
5...Injection unit base, 6...Slide base, 8...Spring, 11...Cam driver,
15...Brake device, 20...Protrusion, 21...
Roller chain, C1...first cam, C2...
Second cam, M...motor, S1 to S4... sprocket.

Claims (1)

[Scope of Claims] 1. A nozzle touch mechanism that moves an injection device to press a nozzle into contact with a mold, which includes a slidable slide base on which the injection device is placed so that it can slide within a certain range, and a motor. The injection device is moved until the nozzle comes into contact with the mold as the cam driver provided on the slide base moves forward and the nozzle comes into contact with the mold. When the nozzle comes into contact with the mold, the cam follower rotates. A first cam is provided on the slide base and rotates when the cam driver moves forward, and a first cam is provided on the slide base and rotates when the cam driver moves backward to release the operation of the brake device. a second cam that presses the injection device via a spring to press the nozzle against the mold, and rotates as the cam driver moves backward to release the pressure contact between the nozzle and the mold; A nozzle touch/sprue break mechanism characterized by being provided with a protrusion that abuts when the cam driver moves backward and moves the slide base rearward. 2. The nozzle touch/sprue break mechanism according to claim 1, wherein the drive of the motor is controlled by a limit switch that detects the position of the cam driver and the slide base.