JPH084859B2 - Overload prevention device for transfer press - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer press for continuously and automatically operating at high speed, which eliminates the risk of damage to various parts due to overload on the cam mechanism in an emergency when the transfer is stopped.

[0002]

2. Description of the Related Art A transfer feeder of a transfer press holds a material by a pair of feed bars extending horizontally from both sides toward the center of the press and conveys the material to a desired die position by a three-dimensional motion to continuously transfer the material. It is a system that mass-produces molding with extremely high efficiency by repeating the operation of opening the molded product after receiving press molding.
Although there is a hydraulic cylinder or gear transmission for driving the feed bar, a configuration in which a cam and a link mechanism are combined to convert the rotational movement of the drive source into a desired linear movement is often adopted. That is, from a configuration in which three sets each having one cam fixed to one rotating shaft are provided to share a single motion, by changing the phase of three sets of two cams per one rotating shaft. Various mechanical configurations have been implemented, including those that are fixed and combined with a swing arm to translate to the desired motion.

In order to receive the change in the outer peripheral curved surface of the cam which rotates by the rotation of the rotating shaft and convert it into a linear motion, generally, the rolling contact is made while rolling on the transfer surface of the outer periphery of the cam. A normal mechanism is to rotatably attach a swing arm having a roller for receiving a phase change at one end. For example, as shown in FIG. 3, the other end of the swing arm 2a having a roller 21a rolling on the outer peripheral surface of the cam 12a at one end is
It is fixed to the feed bar connecting portion 67a via the link 101. An air cylinder 4a, whose tip presses against the swing arm 2a, is attached, and compressed air is supplied to this piston side chamber 42a from a compressed air source (not shown), and the piston rod 4a
The swinging arm is always urged toward the cam side at the tip of 1a so that they are pressed against each other.

There is no particular problem when the rotation of the cam driving the three-dimensional linear movement of the transfer feeder and the movement of the feed bar move normally in synchronization with each other.
Since various elements are complicatedly involved in the forming operation of the press, it is not always possible to guarantee that normal movement is always continued, and the feed bar may be blocked by some reason and stopped. At this time, the cam that receives the driving force from the drive source cannot stop the rotation instantaneously, so if one is left as it is and the other continues to rotate, the member connecting them, such as the swing arm, the link, or the pin. It is inevitable that somewhere will be damaged by excessive force.

In order to prevent this trouble, some proposals have been made in the past. For example, in the case of FIG. 3, the pin 102 that rotatably connects the swing arm 2a and the link 101 is set in advance as a breaker pin, and when the feed bar is stopped, it is preferentially cut here. This prevents damage to the entire device.

Japanese Utility Model Laid-Open No. 4-432 (also Japanese Utility Model Laid-Open No. 4-431, which has the same effect) shown in FIG. 4 is also an example of an overload preventing device in an emergency when the feed bar is stopped, and is rotated by a rotary shaft 1b. Lift system cam 12b
The other end of the swing arm 2b, which has a roller 21b rotatably pressed against the outer peripheral surface of the one end, has a basic structure for moving up and down the feed bar 6b via the engaging pin 103 and the vertical shaft 104. Since the fulcrum shaft 22b that supports the swing arm is liftably supported by the overload cylinder device 4b that is fixedly installed in the feed bar box, something abnormal occurs in the movement of the feed bar 6b. When stopped, excessive pressure is applied to the hydraulic oil in the cylinder, a relief valve (not shown) communicating outside the cylinder opens, the hydraulic oil is once released, the fulcrum shaft 22b is lowered, and the pressure contact with the outer peripheral surface of the cam is released. It prevents damage before it happens. Others
When an abnormal overload occurs for some reason on the command bar side
Immediately cut off the transmission of driving force from the driving side.
We can find many proposals to prevent damage and failure of
For example, in Japanese Utility Model Publication No. 2-30106, press
Between the drive shaft and the transfer transmission shaft that are interlocked with the rotating shaft of
The second torque can be freely engaged and disengaged with the interposed torque limiter.
A limiter is provided, and this torque limiter is an independent drive model.
Connected to the data. Conventional torque limiters are overloaded
Therefore, if the mesh is disengaged, manually engage the mesh.
After returning, the second torque limiter was driven
He claims to be able to return mechanically. Actual exploitation Sho 57-1562
In No. 41, the transfer drive shaft 1 and the driven shaft side are driven.
A torque damper is installed between the drive shaft side and
The shock torque applied during operation is buffered.
It The torque damper is a differential gear mechanism that is connected to the drive shaft.
The case that encloses the entire device is equipped with a hydraulic cylinder.
It is kept in a fixed position by power, but in overload
It is configured to rotate and absorb this. Furthermore
No. 62-13704 discloses a press side drive shaft and a feeder.
Connect the cam and the link by interposing the connecting part between the side drive shaft and
The feeder is operated via the combined transmission mechanism,
If an overload is applied to the feeder side drive shaft,
Overload consisting mainly of a clutch that disengages
Built-in prevention mechanism .

[0007]

Among the transfer bar overload preventing devices, the structure shown in FIG.
Every time a trouble occurs, you have to insert your hand into the complicated cam drive unit to replace the pin, and the feed bar stop accident causes frequent stoppages due to poor coordination with the mold and die holder. If you do so, there is a problem that you cannot bear the trouble and it is extremely unfavorable in terms of occupational safety. In addition, in the conventional technique shown in FIG. 4, the position of the fulcrum of the swing arm, which is an important point for determining the base point of the movement of the feed bar, is set to the fluid pressure cylinder regardless of whether the fluid pressure cylinder is applied for mere urging. Since it fluctuates directly according to the external load via the pressure cylinder, it is difficult to say that it is preferable in terms of the accuracy of the operation locus, and a problem remains. Also, real
Hei 2-30106, Japanese Utility Model Publication 57-156241.
Prior Art Related to Japanese Patent Publication No. 62-13704
Is the transfer work in each configuration.
Prevents damage to equipment when abnormal overload occurs during operation
To prevent the overload that cuts off the transmission of driving force
All parts (torque limiter) are connected to the drive shaft and transmission shaft.
It is common in that it is provided at the junction. Feed bar says
Needless to say, three-dimensional movement of clamp, lift and feed
Therefore, overload may occur in any of the exercises.
The ability cannot be denied. Therefore, the overload for each dimension
Must be dealt with
As with all prior art, there is no guarantee that it will occur.
Install an overload prevention device directly on the transmission shaft itself
If it is a system that
For example, the setting should not exceed the total drive torque for each single dimension.
If that were not the case, it would not be perfect. Or overloaded
Designed the prevention device assuming that the occurrences do not overlap each other
However, the torque below the torque showing the highest value in each dimension
Luk setting is meaningless to achieve the purpose
There is no requirement for strength of the structure because it cannot escape from slander.
Cost is high and design and manufacturing costs cannot be ignored.
The problem of affecting to a certain degree remains.

Apart from this, as a problem imposed on the entire transfer press, there is an increase in the speed of the press work. That is, there is a limit on the rotation speed for rolling the roller of one swing arm on one cam to convert the rotational motion of the cam into a linear motion and transmitting it to the feed bar. When the roller rotates, the roller begins to jump apart from the transfer surface on the outer circumference of the cam and cannot accurately follow the fluctuation of the outer peripheral curved surface. With regard to transfer presses as well, in order to improve work efficiency, machine operation speeds up, and attention is paid to the jerk on the cam rolling surface of the roller as the cause of noise and vibration when transmitting the operation from the cam to the roller. became.

To solve this problem, for example, as shown in Japanese Unexamined Patent Publication No. 63-41304 shown in FIG. 5, two advance swing arms 2c connected to a link 101 for advancing or retracting the feed bar 6c. 3c is supported by a common fulcrum shaft 22c, and the roller 2 is attached to one end of both swinging arms.
1c and 31c, and both rollers roll on the outer peripheral surfaces of two cams 11c and 12c which are rotated by a rotating shaft 1c. In this case, in order to accurately transmit the fluctuation of the phase of the cam, it is necessary for both rollers to roll on the outer peripheral surface of the cam while always being in pressure contact with each other, and the disc spring 105 is attached in order to exert the pressing force. There is. That is, this disc spring 105
3 plays the role of the air cylinder 4a in the prior art of FIG. 3, and the roller is separated from the transfer surface on the outer circumference of the high-speed rotating cam due to the centrifugal force and inertia, and the fluctuation of the phase of the cam is not accurately transmitted to the roller. To prevent this.

However, even if this conventional technique appropriately responds to the demand for high-speed operation of the transfer press, it cannot deal with another big problem of overload treatment due to stop of the feed bar, and damages of equipment and the like. I have to say that defense against the danger of is not considered. This means that as a mechanism of operation conversion in a heavy machine with a large driving force such as a transfer press,
It is an extremely unstable factor.

In order to solve the above two problems at the same time, the present invention is a cam mechanism for high speed operation, which is composed of two cams, so-called positive movement cams, and two rocking arms. It is an object of the present invention to provide an overload device for a transfer press, which can immediately respond to an unexpected abnormal stop of the feed bar and can easily return to the original setting condition as soon as the cause of the abnormality is released.

[0012]

In a transfer press overload prevention device according to the present invention, a cam mechanism for converting rotational movement of a drive source into linear movement of a feed bar is provided.
Material gripping and each single movement of front-back, left-right, up-down three-dimensional movement
Two cams, a sub cam 11 and a main cam 12, which are attached to the same rotary shaft 1 with a different phase for each movement, a sub rocking arm 2 and a main rocking rocking in contact with the respective cams.
The arm 3 includes two swing arms, and the two swing arms form a scissor-like body that opens and closes about the same fulcrum shaft 22, and one end of the sub swing arm 2 and the main swing arm 3 Rollers 21 and 31 which are respectively in contact with the rolling surface of the cam are rotatably rotatably supported on the other side, and a fluid pressure cylinder 4 is extensible between the two oscillating arms on the other side of the fulcrum shaft 22. The above problem is solved by forming an information transmission path from the fluid drive control device 5 of the fluid pressure cylinder 4 to the cam rotation drive control device.

[0013]

In the cam mechanism of the transfer device according to the present invention, the cams fixed to the common cam shaft for each single movement are two cams which are combined by changing their phases, and the outer peripheral transfer surface of this cam is Two rocking arms each having a roller that presses and rolls are also rotatably attached to two common fulcrum shafts 22 to form scissors-like bodies. Since a fluid pressure cylinder is interposed between the two swing arms in the opposite direction with the roller and the fulcrum shaft separated, one of the swing arms has a reverse direction with the roller and the fulcrum shaft separated. The roller surface presses the cam by the principle of the lever, receiving a force from the rod tip of the fluid pressure cylinder toward the end of the. The body of this fluid pressure cylinder is fixed in the opposite direction to the roller of the other swing arm. That is, the two rocking arms are pivotally supported by a common fulcrum shaft, and the movement of the cam is fed to the feed bar 6 while being pressed by the pressure from the fluid pressure cylinder so as to sandwich the outer peripheral surface of the cam at one end thereof. Connection part 6
Communicate to 7. The relative positional relationship between the two rocking arms is constantly constrained by the pressure of the fluid pressure cylinder to maintain a constant state, and the two rocking arms integrally perform a rocking motion like a rocking arm. Repeatedly, this swinging motion is converted into the linear motion of the feed bar connecting portion 67 and transmitted to the feed bar 6. During this time, the piston of the fluid pressure cylinder interposed between both swing arms hardly moves during normal operation,
It is only enough to perform a fine operation that absorbs a subtle machining error on the outer peripheral surfaces of both swing arms.

When the feed bar 6 is prevented from moving due to some trouble, the rotary shaft of the cam cannot stop the rotation immediately, so that the feed bar connecting portion 67 is tried to be further moved, but the cam and the swing arm do not move. The double cam mechanism is a combination of two rockers. Since the cam is sandwiched by two rocking arms, the fixed positional relationship between the two rocking arms is broken and the piston is partitioned by the piston in the fluid pressure cylinder. The fluid pressure in the chamber changes, and this abnormality is immediately detected by the fluid drive control device 5 to command the stop of the cam drive source, and at the same time, the restraint of the two swinging arms pressing the cam is released. . When the cause of the trouble is removed, the fluid drive device can be operated to immediately restore the current state and restart the transfer press.

[0015]

DETAILED DESCRIPTION FIG. 1 shows the main part of the overload apparatus of the present invention embodiment, the front and rear, left and right, responsibility of the upper and lower three-dimensional motion
Only each single movement (for example, vertical movement) was taken out
It is a key part. FIGS. 2A and 2B are a vertical sectional front view and a plan view illustrating the conversion of the rotation of the swing arm into the linear movement of the feed bar connecting portion. Although other drawings of the entire transfer itself are omitted, the present invention can be applied to any transfer device as long as it is based on the operating principle of combining a cam and a swing arm. In FIG. 1, the cam comprises a rotary shaft 1 driven by a drive source (not shown), two slave cams 11 fixed to the rotary shaft in combination, and a main cam 12. When the roller 21 axially supported by the tip of the slave swing arm 2 extends from the small diameter to the large diameter of the slave cam 11, the main swing arm 3
The roller 31 pivotally supported at the tip of the main cam 12 extends from the large diameter to the small diameter of the main cam 12, and when the roller 21 of the slave swing arm 2 extends from the large diameter to the small diameter of the slave cam 11, the roller 31 of the main swing arm 3 moves to the main diameter. The main cam 12 and the slave cam 12 are arranged along the small diameter to the large diameter of the cam 12.
Since the cam 11 is out of phase with the main swing arm 3,
And従揺movement arm 2 is to cooperate. During normal operation of the device, there is no pressure fluctuation in each chamber of the fluid pressure cylinder 4, and both rollers of both swinging arms are in close contact with the transfer surfaces of both cams to completely follow the rotation of the cams. Convert to linear motion.

Fluid drive controller 5 in this embodiment
Is assembled by members such as the pressure detector 51, the overload valve 52, the pump 53, the operation detector 54, and the non-leak valve 55, and the piping connecting these as shown in the figure. Now, if the feed bar 6 is stopped due to some trouble while the roller 21 of the slave rocking arm 2 is running from the small diameter to the large diameter of the slave cam 11, the roller 21 of the slave rocking arm 2 is driven by the slave 21. Although the pressing force is received from the cam 11, the main swing arm 3 hardly moves together with the feed bar 6 without receiving the pressure force from the main cam 12, so that the slave swing arm 2 rotates around the fulcrum shaft 22 and the fluid pressure is increased. The rod 41 of the cylinder 4 is pressed in the compression direction. That is, since the refracting power about the fulcrum shaft 22 acts on the slave swing arm 2, the pressure in the cylinder side chamber increases, the overload valve 52 operates, and the pressure in the cylinder side chamber is eliminated, so that the slave swing arm 2 moves. The refracting power applied to 2 also disappears. When the overload valve 52 operates, an abnormal signal is transmitted from the operation detector 54 of the overload valve 52, and the rotation of the cam stops urgently.

The roller 31 of the main swing arm 3 is connected to the main cam 12 by the roller 31.
When a trouble occurs in the feed bar 6 and the roller 21 of the sub-oscillation arm 2 stops along the small-diameter to the large-diameter, the roller 21 of the sub-oscillation arm 2 moves from the large diameter of the sub cam 11 to the small diameter of the main oscillation arm. Since 3 does not move much, the rod 41 of the fluid pressure cylinder 4 expands, and the fluid pressure that presses the cam through the rollers is released and reduced. For this reason, the pressure detector 51 is activated, an abnormal signal is transmitted, and the cam rotation is stopped urgently. In this case, since the force for refracting the slave swing arm 2 does not work, it is not necessary to provide an overload valve for releasing the fluid pressure.

Further, when the pressure of the fluid pressure cylinder 4 is set to 0 by the fluid drive control device 5, both swinging arms 2 and 3 can be freely rotated, so that the rollers 21 and 31 and the fluid pressure cylinder 4 are replaced or repaired. There is an advantage in maintenance such as doing.

In the embodiment of the present invention, a special structure is applied to the mechanism for converting the rotational movement of the cam into the linear movement of the feed bar. That is, the main swing arm 3 has a connecting wheel 61 formed at the end portion on the opposite side of the roller 31 and the fulcrum shaft 22, and a disc 62 is rotatably fitted into the inner side of the connecting wheel 61 to form a disc. A pin 63 rotatably fitted in a circular hole provided at a position eccentric from the center has a box body 60 sandwiching both end faces.
The leg portion 64 extending in the linear direction of the box body 60 slidably fits into the guide hole 66 formed in the guide 65, and the opposite side of the box body is fitted to the feed bar 6 It is characterized in that it is fixed to the connecting portion 67.

As shown in FIGS. 2A and 2B, the main swing arm 3 is connected to the feed bar connecting portion 67 at a distance R about the fulcrum shaft 22 and is perpendicular to the feed bar 6 with a stroke S. Give exercise. The center Q of the connecting wheel 61 has a radius R
Since it moves along the circular arc, there is a deviation of the height F of the circular arc from the vertical line. When the center Q is at the point P1, the center of the pin 63 eccentric from the center Q by the distance E and P1
Forms an angle of θ1, but when the center Q moves to the point P2, the angle formed by the center of the pin 63 and the point P2 becomes θ2, and the pin 63 rotates around the center Q in the connecting wheel. To do. Therefore, as long as the condition of E> F is satisfied, if the connecting wheel 61 forming the end of the swing arm 3 swings, the box body 60 connected to the feed bar 6 is guided by the guide 65 and converted into a linear reciprocating motion. It exerts the action of doing.

As shown in FIGS. 4 and 5, in the conventional transfer press, a link mechanism is mainly used to correct the arc movement of the tip of the swing arm into a straight line, but there is rattling. There is a problem in maintaining the accuracy of the product because it results in the addition of additional elements.In addition, when sliding between flat surfaces, which has been widely used in the past, there is a problem in terms of mechanical finishing, and the accuracy of the product is still high. It tends to be a difficulty in maintenance. In this respect, the method of transmitting motion by rotating and sliding on the entire circumferential surface as in the present embodiment is advantageous in terms of easiness of processing, securing of accuracy and its continuation.

[0022]

As described above, according to the present invention, the two rocking arms are brought into contact with the two cams, and the rotary motions of the cams are always followed even during high-speed operation to be converted into accurate linear motions. To the feed bar. In addition to this function, when some trouble occurs on the feed bar side, an emergency cutoff signal is immediately issued to the cam drive source in response to the abnormality, and at the same time, the two swinging arms that press the cam are mutually restrained. Since it is opened, the unreasonable load is not concentrated on any of the members that transmit the operation, and there is no concern that the mechanism will be damaged. Moreover, since the cam stop at the time of this abnormality operates only by the pressure balance between the two rocking arms and does not require the position variation of the fulcrum shaft, which is the basic position, the cam between the cam and the rocking arms is not required. There are no unstable factors related to the reduction of accuracy in the motion transmission, and it is superior to any of the conventional methods in maintaining the product accuracy. Also, when an abnormality is detected and a stop signal is sent to the drive device, and if the cause is removed, a command to restart the operation is received, and the operation is easily returned to the original operation. It also brings good results for improvement and establishment of safe work.

In addition, the fluid pressure cylinder absorbs minute machining errors on the outer peripheral surfaces of the two cams to eliminate the slight vibration to the feed bar connecting portion 67, and the fluid pressure of the fluid pressure cylinder is reduced to 0.
By doing so, each cam and swing arm can be moved freely, maintenance and replacement can be performed easily, and since the link mechanism or flat sliding is not adopted for conversion of movement, it is a rotary sliding between the circumferential surfaces, Smooth transmission with no vibration or rattling, surpassing conventional devices of the same type in terms of maintenance and product accuracy.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional front view (A) showing a part of the details of the same embodiment.
It is a top view (B).

FIG. 3 is a front view showing a conventional technique.

FIG. 4 is a front view showing another conventional technique.

FIG. 5 is a front view showing still another conventional technique.

[Explanation of symbols]

 1 rotary shaft 2 slave swing arm 3 main swing arm 4 fluid pressure cylinder 5 fluid drive control device 6 feed bar 11 slave cam 12 main cam 21 slave roller 22 fulcrum shaft 31 main roller 41 rod (fluid pressure cylinder) 60 box 61 Connecting wheel 62 Disc 63 Pin 64 Leg 65 Guide 66 Guide hole 67 Feed bar connection

Claims (1)

[Claims] 1. A gripping and the material before and after, left and right, in the transfer press which combines an open top and bottom of the three-dimensional motion, a cam mechanism for converting a rotary motion of the driving source into a linear movement of the feed bar, the three-dimensional motion For each single exercise of
Respectively to the same rotary shaft 1 mounted out of phase
Two cams, a sub cam 11 and a main cam 12, and a sub rocking arm 2 and a main rocking arm 3 that rock on contact with the respective cams.
It consists two swing arms, two rocking arms of forming a scissors-like body for opening and closing around the same pivot shaft 22
Then, rollers 21 and 31, which are in contact with the rolling surface of the cam, are rotatably rotatably supported at one ends of the sub-oscillation arm 2 and the main oscillating arm 3 , respectively. The fluid pressure cylinder 4 is interposed between the moving arms so that it can expand and contract.
An overload prevention device for a transfer press, wherein an information transmission path is formed from a fluid drive control device 5 of the fluid pressure cylinder 4 to a cam rotation drive control device.