JP3310734B2 - Safety device for vertical clamping mechanism of injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device in a vertical clamping mechanism of an injection molding machine.
The present invention relates to a safety device for preventing a vertical clamping mechanism from dropping when an endless member (belt or chain) transmitting a rotational force of a motor serving as a driving source for generating a clamping force in the mechanism is broken.

[0002]

2. Description of the Related Art Injection molding machines can be broadly classified according to the arrangement relationship between an injection mechanism and a mold clamping mechanism, such as a horizontal type in which both are arranged in a horizontal direction, a vertical type in which they are arranged in a vertical direction, and an eclectic type. There are things. The present invention relates to a safety device for preventing a fall accident peculiar to a vertical clamping mechanism (hereinafter referred to as a vertical clamping mechanism) of the vertical arrangement. Therefore, first, a general structure of the vertical clamping mechanism will be briefly described.

FIG. 1 is a partially cutaway front view showing a schematic configuration of a vertical clamping mechanism. The vertical clamping mechanism indicated by reference numeral 1 in FIG. It has a structure for vertically moving a movable body 3 mounted to be vertically movable. A mold-clamping motor 12 is used as a drive source that generates this vertical movement, and a brake device 4 is provided as a means for stopping the movable body 3 at an upper position.

[0004] The movable body 3 has a structure in which an upper movable platen 5 and a lower die height platen 6 are connected by four tie bars 7, and a fixed platen 8 integrally fixed to the frame 2 has: The tie bar 7 is vertically penetrated and mounted. The lower die height platen 6 and the fixed platen 8 are connected by a toggle mechanism 9, and the toggle mechanism 9
Is composed of a toggle link 10 arranged in a symmetrical manner on the left and right and a crosshead 11 for driving the toggle link 10. The crosshead 11 is moved up and down by rotation of a ball screw 13 driven and rotated by a mold clamping motor 12, and cooperates with the toggle link 10 to move the rotation of the ball screw 13 up and down of the movable body 3. It performs the function of converting to directional translation. The space between the fixed platen 8 and the movable platen 5 is the mold 1
The mold clamping space 15 is provided with the mounting space 4.

[0005] The brake device 4 has a built-in disc brake mechanism.
3 and functions to lock the movable body 3 so as not to drop from the upward movement position (indicated by the broken line position in FIG. 1) when removing a molded product or replacing a mold.
In this case, the brake-side member to be braked by the disc brake mechanism is the ball screw 13, and the frame 2 is the brake-side member. As the brake device 4 attached to the vertical clamping mechanism, a type in which a braking force is applied when the power is cut off is adopted in consideration of safety during a power failure.

The rotational force of the clamping motor 12 mounted on the die height platen 6 is transmitted to the ball screw 13 via a pulley and an endless member (belt or chain) 16. When the ball screw 13 rotates, the crosshead 11 moves up and down, and the movable head is moved via the toggle link 10.
The up-and-down movement of the Latin 5 occurs (see the broken line). Thereby, the vertical movement of the entire movable body 3 including the movable platen 5 with respect to the outside is realized.

Incidentally, an endless member (belt or chain) 16 used to transmit the rotational force of the motor 12 for clamping to the ball screw 13 during use of the vertical clamping mechanism having such a structure. May break. This is thought to be caused by material fatigue due to repeated use over a long period of time and unexpected excessive load. However, break phenomena often occur suddenly, and it is difficult to prevent this before it occurs. .

Then, once the belt or chain 16
When the ball screw 13 breaks, the force for restraining the rotation of the ball screw 13 disappears, so that the ball screw 13 is in a free rotation state, and the movable body 3 drops downward by gravity together with the mold clamping motor 12 and the like mounted thereon. Will do. If such a rupture accident occurs when the movable body 3 is lifted upward, the falling distance increases, and there is a possibility that the mold 14 and the vertical clamping mechanism itself in use may be damaged. Also,
This can lead to injury to the operator operating the injection molding machine.

[0009]

SUMMARY OF THE INVENTION The present invention is directed to a vertical movable mechanism included in a vertical clamping mechanism when a break occurs in an endless member for transmitting the rotational force of a motor for clamping the vertical clamping mechanism. By providing a safety device to prevent the occurrence of a fall accident, it is intended to prevent damage to the mold and vertical clamping mechanism itself and to protect the operator from the danger of personal injury. is there.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a vertical moving mechanism for a vertical clamping mechanism of an injection molding machine ;
Endless member for transmitting the rotational motion of the motor to the rotating member
And connecting the rotating member and the movable body to each other,
Convert the rotational motion of the material into the vertical translational motion of the movable body
Rotating / translating motion converting means for breaking the endless member.
Injection molding, comprising: a break detecting means for detecting a break; and means for urging a braking force of a rotation braking brake means of the rotating member based on a break detection signal given by the break detecting means. The above technical problem has been solved by a "safety device for the vertical clamping mechanism of the machine".

[0011]

The safety device according to the present invention transmits the rotational motion of the motor for clamping the vertical clamping mechanism of the injection molding machine to the rotating member.
The breakage of the endless member is detected by a breakage detecting means for detecting the breakage of the endless member for applying a braking force of a rotation braking brake means of the rotary member based on a breakage detection signal given by the breakage detection means. It is a force.

Therefore, even if the belt or chain that transmits the clamping force is broken during the operation of the vertical clamping mechanism, the braking force acts on the rotating member (usually a ball screw) to stop and lock the rotational movement. Is done. This makes it possible to move up and down the vertical clamping mechanism
A fall of the body is avoided, and damage to the machine and injury to the operator are prevented beforehand.

The rupture detecting means for detecting the rupture of the endless member can be used to quickly detect the rupture of the endless member used.
It is desirable to use a switching device . There are various types of detection switches that can be used, such as a mechanical type, a photoelectric type (reflection type and transmission type), a magnetic type, an electric type (detects changes in electric capacity and electric resistance), a microwave type, and the like. Conceivable.

When the endless member is broken, the rotating member exerts a braking action, and as a means for stopping and locking the rotating member , a brake device attached to a normal vertical clamping mechanism can be used. Further, in order to energize the braking force of the brake device in response to a break detection signal from the break detection means,
It is possible to use a control device with a built-in CPU for controlling the entire injection molding machine.

[0015]

FIG. 2 is a block diagram showing an outline of a system in which a safety device in a vertical clamping mechanism according to an embodiment of the present invention is connected to a control device of an injection molding machine. In FIG. 2, reference numeral 50 denotes a control device for controlling the entire injection molding machine including a safety device for the mold clamping portion, and includes a CPU (central processing unit including a microprocessor) 51 for controlling the operation of the control device. . The CPU 51 includes a ROM 52 and a RAM 53 that store various programs for controlling the operation of each unit of the injection molding machine, related data, and the like.
An input / output device (I / O) 54 for transmitting and receiving signals and the like to and from each part of the injection molding machine, and input of programs and data;
Operation panel 57 for inputting commands for manually operating each part
Are connected via a bus 58.

Hereinafter, each part of the safety device connected to the input / output device 54 will be described (elements not particularly related to the safety device will not be shown and described). First, the voltage detector RV55 connected to the input / output device 54
Is a belt breakage detection switch 60 disposed in the vicinity of the endless member 16 (in this embodiment, a belt; the same applies hereinafter) of the vertical clamping mechanism shown in FIG.
Is connected to a 24 V DC power supply. This R
V55 responds to the voltage sensing command sent from the CPU 51 via the input / output device 54 at a very short cycle, and sends a signal indicating the open / closed state of the belt break detection switch 60 to the CPU 51 via the input / output device 54. send.

The belt break detection switch 60 is connected to the belt 1
When the belt 6 is normal, it keeps the closed state and opens only when the belt is broken. Therefore, the RV 55 detects DC 24 V during normal operation, and detects a voltage drop to the ground potential when the belt is broken.

Next, the block designated by reference numeral 56 is:
A brake control unit for controlling the brake mechanism 40 is connected to the input / output device 54, and
V DC power supply and the brake switching unit 70. The brake switching unit 70 includes a contact 72 for supplying / cutting off a 90 V DC voltage to the brake mechanism 40 and a relay (relay coil) 71 for opening and closing the contact. The contact 72 is configured to maintain a closed state while the relay 71 is energized / excited, and maintain an open state while the energization to the relay 71 is interrupted. The brake control unit 40 controls switching of the braking mechanism 40 between the braking state and the non-braking state by supplying / cutting off a 24 V DC voltage to / from the relay 71 in accordance with a command from the CPU 51.

As described above in the description of the prior art, the brake mechanism 40 is of a type in which a braking force is applied when the power is cut off in consideration of safety at the time of a power failure or the like. I do. Therefore, when the contact 72 is opened, the braking force of the brake mechanism 40 is urged and maintained, and conversely,
While the contact 72 is closed, the braking force of the brake mechanism 40 is not energized, and the state in which the rotation of the ball screw 13 of the vertical clamping mechanism is allowed to be maintained.

The operation of the above system will be described on the premise of the above configuration and the function of each unit. When the system starts,
It is assumed that the braking force of the brake mechanism 40 is energized and the rotation of the ball screw 13 of the vertical clamping mechanism is locked. Further, it is assumed that the belt 16 is in a normal state.
First, in order to activate the vertical mold clamping mechanism and start the vertical movement of the movable body 3, the keyboard of the operation panel 57 is operated to release the braking force of the brake mechanism 40, and the mold is clamped according to a required operation. The rotation of the motor 12 is started. The release of the braking force of the brake mechanism 40 is executed by sending a command from the CPU 51 to the DV 56, connecting and exciting the relay 71 to a power supply (DC 24 V), and closing the contact 72.

If the belt 16 does not break, the work including the mold clamping operation is performed as usual, and the power to the relay 71 is cut off at the end of the work, and the braking force of the brake mechanism 40 is energized. Prepare for the next work as a state. On the other hand, if the belt 16 is broken during the operation, the belt break detection switch 60 is opened. Voltage detection unit RV receiving a sensing command from CPU 51 in a very short cycle
55 detects a voltage drop and sends a belt break detection signal to the CPU 51. The CPU immediately sends a brake braking force urging command to the brake control unit DV56 via the input / output circuit 54 to stop energization / excitation of the relay 71, and
To open. As a result, the brake mechanism 40 supplies the power (D
C90V), the braking force is urged, and the rotation of the ball screw 13 is locked.

By the above-described series of operations, even if the belt 16 is broken, a fall accident of the movable body 3 is prevented, and a machine damage accident and a personal injury accident of the operator are prevented from occurring. The replacement / repair operation of the broken belt 16 can be performed in a state where the braking force of the brake mechanism 40 is maintained (power supply is cut off).

The belt break detection switch 60 for detecting the break of the belt 16 may be of any type as long as it has the ability to quickly detect the break of the belt 16 (or chain). . The available detection switches are classified according to the principle of fracture detection, such as mechanical, photoelectric (reflection and transmission), magnetic, electric (detecting changes in electric capacity, electric resistance, etc.), microwave, etc. Can be mentioned.

Here, a case where a mechanical switch device of the limit switch system is used will be described. FIGS. 3 and 4 are views illustrating a state in which a mechanical switch device based on the limit switch method is arranged near the belt 16 of the vertical clamping mechanism shown in FIG. 1, and FIG. FIG. 4 schematically shows a cross section taken along line L in FIG. In both figures, reference numeral 10
Numerals 7 and 108 denote pulleys connected to the rotation shaft of the mold clamping motor 12 and the ball screw 13, respectively, and the belt 16 is suspended on both pulleys. Brake mechanism 40
In the state where the braking force is not applied, the rotation of the mold-clamping motor 12 is stopped until the belt 16 is broken.
Is transmitted to the ball screw 13 through the orbital motion of the ball screw 13. The switch device 60 for detecting the break of the belt 16 has a built-in limit switch 61, and converts the break of the belt 16 into an electric signal by separating the movable contact member 65 from the fixed contacts 68a and 68b.

The movable contact member 65 is attached to a spring member 64 having one end fixed to a fixed member 66, and is formed integrally with the movable plunger 62. A rolling roller 63 is attached to the tip of the movable plunger 62, and is constantly biased rightward in the figure by the action of a spring member 64. The belt 16 has a certain thickness, and an arrangement is adopted in which the movable contact member 65 and the fixed contacts 68a and 68b surely maintain contact in a normal state where the belt is not broken as shown in the figure.

This state corresponds to the state in which the belt rupture detection switch device 60 in FIG. 2 described above is in the closed state. That is, the fixed contacts 68a and 68b are respectively connected to the DC power supply (24V) and the voltage detection unit RV55 shown in FIG.

If the belt 16 is broken during the operation, the belt 16 is disengaged from the pulley 107, and the rolling roller 63 moves to the right together with the movable plunger 62 and the movable contact member 65 by the action of the spring member 64. Then, the contact of the limit switch is opened. Then, the voltage detection unit RV55 receiving the sensing command from the CPU 51 in a very short cycle detects the voltage drop on the contact 68a side, and
A belt break detection signal is sent to the PU 51. Hereinafter, the CPU 5
As described above, the brake mechanism 40 is immediately disconnected from the power supply in response to the command from 1, the braking force is applied, and the rotation of the ball screw 13 is locked.

Finally, as for the brake mechanism built in the brake device 4, a case where a disk brake mechanism which can be attached to a general vertical clamping mechanism is used as a braking means in the present invention will be described with reference to FIG. explain.

Referring to FIG. 5, the disc brake mechanism 40 generally includes a disc 18 which rotates together with the rotating shaft 17.
With the side plate 1 (on the braking side) fixed to the machine frame side
Basically, a braking force is obtained by pressing the armature 9 against the armature 20, and an electromagnetic force is used for driving the armature 20 (in some cases, hydraulic pressure or air pressure is used).

The disk 18 is usually provided with an axial groove such as a spline 22 formed on the outer peripheral surface of the inner driver 21 on an inner driver 21 fixed to the rotating shaft 17 (rotated together with the ball screw 13) on the braking side. The rotation shaft 17 is always rotated together with the rotation shaft 17 while being movable in the axial direction of the rotation shaft 17.

The disk 18 is mounted with a slight allowance with respect to the inner driver 21 for smooth movement in the axial direction and lubrication. There is play, and there is also some play in the direction in which the surface of the disk 18 is inclined with respect to the rotation shaft 17.

Further referring to the details of the figure, a disk-shaped side plate 19 and a frame case 23 are fixed at intervals by three spacer screws 24, and are provided between the side plate 19 and the frame case 23. It has a structure in which the disk 18 and the armature 20 are arranged.

The armature 20 is disposed between the disk 18 and the frame case 23, and is movable in the axial direction of the rotary shaft 17 with the spacer screw 24 as a guide. The frame case 23 has an annular storage groove 2 on the inner surface side.
A coil 26 for generating an electromagnetic force and a spring 27 are mounted in the groove 25. Annular brake pads 28 and 29 are attached to the back surface of the side plate 19 and the surface of the armature 20.

The armature 20 is pressed from the back side by a spring 27 and constantly presses the disk 18 against the brake pad 28 of the side plate 19 via the brake pad 29, so that the armature 20 is in a braking state unless power is supplied to the coil 26. Yes (negative actuation type). When power is supplied to the coil 26, the armature 20
Side to release the restraint of the disk 18.

When the removal of the molded product is completed and the process proceeds to the next injection molding operation, or when the exchange of the mold 14 is completed and the injection molding is resumed, the braking by the disk brake mechanism is released and the mold is released. The fastening motor 12 is driven in a direction opposite to the direction when the mold is clamped. As a result, the movable body 3 descends and the mold 14 is clamped. At this time, the disc 18 of the disc brake mechanism whose braking has been released is rotated by the rotating shaft 17.
And is rotated together with the ball screw 13.

If the belt 16 breaks during the operation, the power to the coil 26 for generating electromagnetic force is cut off, and the force for pulling the armature 20 toward the frame case 23 disappears. Then, the armature 20 is pressed from the back side by the spring 27, and the brake pad 2
The disc 18 is pressed into contact with the brake pad 28 of the side plate 19 via 9. Thereby, the ball screw 13
Is applied to the rotating shaft 17, and the ball screw 1 is rotated.
The rotation of the movable body 3 is locked to prevent the movable body 3 from falling.

[0037]

According to the safety device of the vertical clamping mechanism of the present invention according to the present invention, the ball a rotational force of the mold clamping motor 12 threaded (times
Even if a break occurs in the endless member (belt or chain) used for transmission to the transfer member ), the movement of the vertically movable portion included in the vertical clamping mechanism is immediately stopped. Thus, it is possible to prevent the mold and the vertical clamping mechanism from being damaged due to an accidental drop of the heavy vertical movable portion, and to protect the operator from the risk of personal injury.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view schematically showing a general structure of a vertical clamping mechanism.

FIG. 2 is a main block diagram showing an outline of a system in which a safety device in a vertical clamping mechanism according to an embodiment of the present invention is coupled to a control device of an injection molding machine.

FIG. 3 is a front view schematically showing the structure and arrangement of a belt breakage detection switch used in the embodiment of the present invention.

FIG. 4 is a diagram schematically illustrating a cross section taken along a line L in FIG. 3;

FIG. 5 is a schematic view illustrating the structure of a disc brake mechanism that can be employed in the brake device 4 attached to the vertical clamping mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vertical clamping mechanism 2 Fixed frame 3 Movable body 4 Brake device 5 Movable platen 6 Die height platen 7 Tie bar 8 Fixed platen 9 Toggle mechanism 10 Toggle link 11 Crosshead 12 Motor for clamping 13 Ball screw 14 Mold 15 Mold clamping space DESCRIPTION OF SYMBOLS 16 Endless member (belt or chain) 17 Rotating shaft 18 Disk 19 Side plate 20 Armature 21 Inner driver 22 Spline 23 Frame case 24 Spacer screw 25 Groove 26 Electromagnetic force generating coil 27 Spring 28, 29 Brake pad 40 Brake mechanism 50 Control device 51 CPU (Central Processing Unit) 52 ROM 53 RAM 54 Input / Output Device 55 Voltage Detector 56 Brake Controller 57 Operation Panel 60 Belt Break Detection Switch 61 Limit Switch 6 The movable plunger 63 rolling roller 64 spring member 65 movable contact member 66 fixed member 68a, 68b fixed contacts 70 brake switching portion 71 relay (relay coil) 72 contacts

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 45/64-45/84 B22D 17/26

Claims (1)

(57) [Claims] 1. Vertical movement of a vertical clamping mechanism of an injection molding machine
Moving body and a motor for transmitting the rotational movement of the mold clamping motor to the rotating member.
An end member, a rotation / translational motion converting means for coupling the rotating member and the movable body, and converting the rotating motion of the rotating member into a vertical translational movement of the movable body; and breaking the endless member. An injection molding machine, comprising: a break detecting means for detecting a break force; and a means for urging a braking force of a rotation braking brake means of the rotating member based on a break detection signal given by the break detecting means. Safety device for vertical clamping mechanism.