JPS5814147B2 - Kousakuhen Atsushiyukusouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an apparatus for compressing a workpiece by the relative movement of a pair of dies.

Patent No. 1015288 (Japanese Patent Publication No. 54-41
No. 682), a press ram carries a die in cooperation with another die to act on a workpiece, and two mutually pulling electromagnets drive said ram through a working stroke to force said workpiece. a workpiece compression device, the workpiece compression device being relatively movable to compress the workpiece between the two dies, and a control circuit controlling the compression of the workpiece by controlling the energization from the power supply of the electromagnet. Are listed.

In one embodiment, the control circuit provides a pulse of predetermined amplitude and duration to the electromagnet, the amplitude and duration of the pulse influencing the shape of the ram's force-motion characteristic curve.

In a second embodiment, the control circuit is a feedback circuit containing a force transducer to ensure that a constant force is applied throughout the compression stroke.

Although both control circuits provide adequate control under certain conditions, they lack the efficiency and safety characteristics necessary for large scale production.

According to the invention, said control circuit comprises a drop-down circuit adapted to limit the energization of the electromagnet to a value that produces a small closing force, said drop-down circuit being deenergized in response to a predetermined distance between said die molds. a force transducer that monitors the force between the die molds, and a force control circuit that deenergizes the electromagnet in response to the monitored force when the monitored force reaches a predetermined value. It is characterized by

In this manner, the ram is moved into gentle initial contact with the workpiece, after which the lowering circuit is deenergized to apply sufficient actuation power and therefore sufficient force.

This is particularly advantageous in certain crimping operations where high impacts can damage the work piece (terminal) or result in a poor crimp.

In order to protect the operator and equipment from injury and damage, respectively, the control circuit comprises a clock circuit, which circuit terminates the die closing cycle if a critical force is not reached within a predetermined time. act.

Next, embodiments of the present invention will be described with reference to the drawings.

The compression apparatus of FIGS. 1 and 2 generally includes a number of features not shown in these figures.

In particular, these figures do not show the feed mechanism for feeding the terminal and/or the feed mechanism for feeding the stripped conductor between the dies.

These details are not necessary for understanding the invention and have been omitted for the sake of clarity.

The compression device has a frame or housing containing a metal base plate 12 that rests on top of a workbench 10.

Box-shaped support housing structure 1 containing a magnetic actuation mechanism
8 is attached to the metal bottom plate 12.

The actuation mechanism is connected to a ram 20 having a die 22 at its lower end.

As best seen in FIG. 2, the ram 20 is connected to a ram shaft 24 that extends vertically through the housing structure.

The top of the ram shaft 24 includes a flange member 26 that surrounds an upper portion of the shaft 24 and a spring member 28 .
The spring member abuts the top surface of the housing structure 18 around the hole through which the shaft 24 moves during operation of the press.

A suitable auxiliary bearing 29 is mounted on the top surface of the housing structure 18 to support the shaft 24 for relative sliding movement.

Spring member 28 is in compression with sufficient force to force the ram shaft and structures connected thereto rapidly toward the position shown in FIG. 1 in the absence of a magnet attracting force.

The lower magnet 30 of the die-type closure device is attached to the housing structure 1
8 and thus fixed with respect to ram axis movement.

The magnet has a central hole through which a ram shaft 24 passes, and the ram shaft 24 is connected to the housing structure 18 by a conventional main bearing 36.
is supported in said central hole for longitudinal sliding movement relative to said center hole.

The upper magnet 32 of the die closure device is secured to the ram shaft by a keyed threaded sleeve 38 as shown in FIG.

The upper surface of the fixed lower magnet 30 carries a cushion 34 in the form of a sheet of Mylar or other plastic, which is shown in FIG. prevents surface engagement of the two magnets while in the closed position.

The cushion 34 also serves to maintain the spacing between the two magnets so that they do not stick to each other.

Each magnet contains a concentrically extending recess within it, which is shown as recesses 40, 42 in FIG.

These recesses contain coils WI, W2 and are connected to power supplies and control circuits in a suitable manner as detailed below.

The die mold 50 fixed to the bottom plate 12 is connected to the die mold 2.
2 and a force transducer 5 below the die 50.
2 is provided.

The force transducer is coupled to a control circuit, shown schematically as box 63 in FIGS. 1 and 2, as described below.

The compression device also includes a switch 33 , one contact of which is mounted on magnet 32 and the other contact mounted on magnet 30 .

This switch operates in conjunction with the drop-down circuit to de-energize the circuit after initial engagement of the die 22 with a terminal or other workpiece.

The metal base plate 12 also includes a photoresponsive element 53.

The element may be in the form of a conventional photoconductor. A light source (not shown) for controlling the electrical output of the photoresponsive element 53 is mounted on the underside of the plate 55 .

The operation of the photoresponsive element with respect to the control circuit in the present invention will be detailed below.

In operating the present compaction apparatus, the apparatus is initially in the position shown in FIG. 1, with the die 22 in the upper position separated from the lower die 50.

During the crimping operation, the terminal T is placed on the lower die and the stripped portion of the conductor W is placed into the crimped portion of said terminal.

When the coils WI, W■ are energized, a magnetic field is generated in the magnets 30, 32, creating a force that pulls the two magnets together.

Because the magnet 30 is fixed to the housing structure 18, the closing force of the magnet causes the ram 2, which carries the die 22 downwardly, to move toward the terminal T and the lower die 50.

This force is detected or sensed by transducer 52 to generate a signal that is used to selectively terminate the die closure cycle.

FIG. 4 is a block diagram of a control circuit used in the present invention.

It has been found that excellent quality crimps can be obtained over a wide range of wire sizes if the crimping cycle is terminated when the force acting on the terminal reaches a predetermined critical force.

Based on this discovery, the control circuit includes a force responsive control circuit 114 that terminates the crimping cycle when the force acting on the terminal reaches a critical value.

Generally, a die closing device using the control circuit of the present invention performs the following sequence of operations.

Magnet 3032 is initially in the remote position shown in FIG.

Closing a switch 116, such as a footswitch, energizes the electromagnet.

When switch 116 is closed, starting circuit 108 generates a starting signal to energize drive circuit 104 .

The start signal is present during the entire cycle.

By energizing the drive circuit 104, the current is transferred to the DC power source 1.
00 to the coils WI of electromagnets 30 and 32. Flows to WI [.

A regulated DC power source 102 is used to energize the circuitry of the control circuit.

The output of the DC power source 100 is the regulated power source 1
It is considerably larger than the output of 02.

For example, power supply 100 provides approximately 160 volts DC while regulated power supply 102 provides 30 volts DC.

The relatively high potential provided by power supply 100 often exceeds the 900 K required to obtain a good crimp for a given period of time.
It is necessary to generate large crimping forces in the region of 2000 lbs.

The magnets are coupled when current from the power source 100 energizes the coil 10 of the electromagnet shown schematically in FIG. 4 and corresponding to electromagnet 30, 32 of FIGS. 1 and 2.

The initial speed at which the magnets approach each other is controlled by the drop-down circuit 112.

The drop-down circuit limits the average drive current to the electromagnet to cause die 22 to initially engage terminal T with little kinetic energy.

Therefore, damage to the terminal T that often occurs when the die 22 is rapidly initial engaged with the terminal T is prevented.

When initial contact occurs, the drop circuit is deenergized and the drive current is increased to increase the traction between the magnets.

Because of this increased drive current, the required crimping force is rapidly developed between the dies.

As will be discussed in more detail below, the drop-down circuit 112 intermittently de-energizes the disabling circuit 109 to intermittently interrupt the drive current through the drive circuit 104.

Intermittent interruptions of this drive current reduce its average value and limit the closing force.

The force between the die molds, that is, the force acting on the terminal T, is detected by the force transducer 52, transmitted to the force control circuit 114, and converted into a proportional potential.

The force control circuit 114 also includes a reference potential proportional to the critical force.

Note that reaching the critical force means that crimping has been performed.

Circuit 114 also includes a comparator that compares the reference potential with the force transducer supply potential, and when the two potentials match, generates an output signal that acts on starting circuit 108 to interrupt the starting signal and terminate the crimping cycle. let

When a foreign object of at least the expected size and shape accidentally enters the crimping area, the electro-optic protection circuit 121 acts to generate an output signal, which acts on the starting circuit 108 to interrupt the starting signal. do.

It is possible for foreign objects, such as wrenches or screwdrivers, to get between the dies and disable the electro-optic protection circuit.

As will be discussed in detail below, the control circuitry includes additional safety features that act to terminate the closure cycle when such foreign objects enter between the dies.

When a screwdriver or wrench is inserted between the dies, for example, the magnets 30, 32 can only be moved a sufficient distance to prevent the contacts of the switch 33 from closing.

In this way, a critical force is not reached and only a small force is applied to the foreign object between the dies.

An additional safety feature that starts at the beginning of a cycle is a clock circuit 110.

This circuit is a timed circuit that starts at the beginning of the die closure cycle.

If the critical force is not reached within the predetermined time, the timer circuit generates an output signal which signals the start circuit 108 to interrupt the start signal and signals the override circuit 109 to activate.

The output from this override circuit 109 generates a warning signal to notify the operator that there is a malfunction in the equipment and prevent further cycles from being initiated until the control circuit is manually reset by the operator.

The operation of the control circuit in the present invention will be further detailed with reference to FIG.

Elements with the same number in FIGS. 1-4 correspond to the same elements.

Switch 116 is closed to begin the die closure cycle, which in the particular embodiment described above is the crimping cycle.

Prior to the closure of switch 116, capacitor C2 is charging through 30 volt conductor 113 from regulated DC power source 102.

When switch 116 is closed, the potential of capacitor C2 appears at the anode of transistor Q2, which is like a double base diode.

This transistor may be a 2N6027 unijunction transistor (trade name).

This double base diode becomes conductive when the anode potential is in a predetermined relationship with the gate potential.

To turn off this transistor, a negative pulse is applied to the anode to bring the anode potential to approximately ground potential.

By applying the voltage of capacitor C2 to the anode of transistor Q2, the transistor becomes conductive.

As a result, the potential at the connection point a in the drive circuit 104 rises, turning on the transistor Q11.

When transistor Qll conducts, transistor Q12
,Q. 3, Q, and 4 are also conductive, energizing the coils WI and W, and generating a traction force between the magnets 30 and 32.

Components of the drop-down circuit 112 are feedback coils L physically located in the vicinity of the coils WIW2, and the currents in these coils generate induced currents in the feedback coils L.

Switch 33 is open from the beginning.

One terminal of the feedback coil L is connected through a suitable resistor to a 30 volt conductor 113, and the other terminal is coupled to the reversing input of an operational amplifier OP1 connected as a trigger circuit.

The operational amplifier O P 1 may be a conventional Schmitt trigger.

Before the coil L is energized, the output potential of the trigger circuit OP1 is low, thus keeping the transistor Q1o in a non-conductive state.

When a current is induced in the feedback coil L, the conductor 1
The potential of capacitor C6 previously charged from 13 drops.

When the trigger voltage is reached, the output of circuit OP1 rises to a potential sufficient to turn on transistor Q10.

The emitter of transistor Q10 is coupled to the base of transistor Q6 in disabling circuit 109.

Thus, when transistor QIO conducts, a positive bias is applied to the base of transistor Q6 to turn off transistor Q6, and the potential at connection point a rapidly drops to turn off transistor Q11.
Next, transistor Q12 of the drive circuit. Turn off Q13 and Q14.

This prevents the current from flowing any further through the coils WI, W2.

As the current in feedback coil L decreases, the potential of capacitor C6 increases, causing the output of circuit OP1 to return to a low state and turning off transistors QIO and Q6.

As a result, the potential at node a of drive circuit 104 increases again, turning on the drive circuit and causing current to flow through coil WI. It will now flow through WII.

In this manner, drive circuit 104 is rapidly energized and deenergized to limit the average current in coils WI,W.

This small average current creates a small traction force between the magnets 30, 32, which limits the speed at which said magnets initially approach each other.

As a result, the die 22 gently lowers onto the terminal T.

When the die 22 contacts the terminal T, the switch 33 closes, keeping the output of the trigger circuit OP at a low level and keeping the transistors Q6 and QIO non-conductive.

The operation of switch 33 is best understood by reference to FIGS. 1 and 2.

One contact of this switch is mounted on magnet 30 and the other contact is mounted on magnet 32.

These contacts close when both magnets are separated by a predetermined distance.

This distance corresponds to the distance between the dies 22.50 when the die 22 first contacts the terminal T.

When transistor Q6 turns off, the potential at node a rises and remains at this elevated high level for a sufficient period of time for the current in coils W■, W■ to reach a value sufficient to generate a large traction force between the magnets. stay.

Of course, this force is transmitted to the ram 20 causing it to approach and lower onto the terminal T.

The dies 22.50 thus engage with sufficient force to provide a good crimp.

The force acting on the terminal is monitored by force transducer 52.

The output of transducer 52 is coupled to force control circuit 114.

This force control circuit also contains an operational amplifier OP2 connected as a comparison circuit.

The output of circuit OP2 is connected to the gate terminal of transistor (double base diode) Q9.

The anode of transistor Q9 is connected to a reference voltage source in the form of a potentiometer 122.

The potential at the wiper of potentiometer 122 is proportional to the desired critical force.

As the force acting on force transducer 52 increases, its potential increases, increasing the input to the reversing side of circuit OP2 and decreasing the potential at its output.

When the force acting on terminal T corresponds to a critical force, transistor Q9 is turned on.

The cathode of transistor Q, is coupled to the base of transistor Q1 of starting circuit 108.

When the transistor Q9 becomes conductive, the transistor Q1 becomes conductive, and the anode of the transistor Q2 becomes close to the ground potential and is turned off. When the transistor Q2 is turned off, the potential at the connection point a of the drive circuit 104 changes to the potential of the transistor Q11.
drop to a value sufficient to turn off the drive circuit 104.
Deactivate.

In this way, as soon as a critical force is reached, the drive circuit is disconnected from the coil and the die closing cycle is terminated.

The magnet returns to its initial open position under the control of biasing spring 28.

The critical force for terminating the closure cycle is determined by the potentiometer 12
This can be easily changed by changing the potential at 2.

Let us assume that a foreign object such as a screwdriver is placed on the die 50.

The control circuit includes a clock circuit 11 that operates in conjunction with a drop circuit 112.
Contains 0.

When starting circuit 108 operates to conduct transistor Q2, transistor Q3 of clock circuit 110 turns off and charges capacitor C1.

Capacitor C1 forms part of a timing circuit that includes resistors 124, 126 and transistor Q3.

Capacitor C1 continues to charge to a critical voltage that turns on transistor Q4.

As mentioned above, once capacitor C1 is charged, die 22 is slowly lowered by the action of lowering circuit 112 into engagement with the screwdriver.

Since the acting force is small, it does not damage the die mold.

The switch 33 is configured so that the contact will not close when a relatively large foreign object such as a screwdriver is on the die 50.

However, the height of the foreign object shall be greater than the height of the contact to be crimped.

Generally, in such cases, when die 22 first contacts the foreign object, magnets 30, 32 are not close enough to engage the contacts of switch 33.

The descending circuit is thus active and limits the force exerted by the magnet so that a critical force is never reached.

When transistor Q4 reaches a critical voltage, it conducts and turns on transistor Q1 of the starting circuit, which in turn turns on transistor Q2.

Also, when transistor q turns on, transistor Q
5 is conductive, so the transistor Q of the disabling circuit 109
7. Q8 becomes conductive.

When transistor Q8 becomes conductive, light 111 is illuminated to indicate to the operator that there is a problem with the equipment.

When the transistor Q7 is conducting, the connection point a is connected to the drive circuit 10 even if another die closure cycle starts.
4 is prevented from rising to the potential required to turn on.

Transistors Q7jQ8 remain conductive until the control circuit is manually reset by the operator by closing reset switch 115.

Transistor Q2 turns on due to the turn-on of transistor Q1.
- Q3- Even if Q4 turns off, transistor Q5
Note that remains conductive.

As long as transistor Q5 conducts, transistors Q7,
Q8 remains conductive.

If the operator attempts to start another cycle without resetting the circuit, the cycle will not start because the cathode of transistor Q2 is shorted to ground by conduction transistor Q7.

When switch 115 is closed, transistor Q5 turns off, thus turning off transistors Q7 and Q8, allowing node a to rise to the drive circuit turn-on potential when switch 116 is closed.

Another safety device in the form of an electro-optical protection circuit 121 is included in the control circuit of the present invention.

This safety device protects the operator in the event that the operator accidentally puts his hand between the die molds and closes the switch 116.

1 and 2, a plurality of photoresponsive elements, such as photoconductors, are mounted on base 12 of housing structure 18. Referring to FIGS.

A light source for energizing these photoresponsive elements may be mounted on the underside of the cross plate 55 of the housing structure 18.

The resistance of a photoconductor varies inversely with the intensity of the received light beam.

Therefore, when the optical path between the light source and the photoconductor is not interrupted, the resistance of each photoconductor is at its lowest value. When the light to the photoconductor is interrupted, the resistance increases. Said photoconductor is protected by electro-optic protection. It is connected to an arithmetic amplifier i0P3 forming part of the circuit 121.

Whenever all the incident light beams of the photoconductors 53, individually named PC1PC2, .

When the light beam to the photoconductor is interrupted, such as when an operator places his hand on a die-shaped area, the photoconductor PC1. PC
2,..., some resistance of PCn increases and amplifier OP
When the photoconductor has a high resistance, the potentials at the anode and gate of transistor Q1 have the predetermined relationship necessary to make transistor Q15 conductive.

When transistor Q15 turns on, transistor Q
1 will turn on and the drive circuit 104 will be prevented from starting, or if already activated, will be stopped.

In this way, if the operator places his hand in the vicinity of the die, the light beam to a significant number of the photoconductors is interrupted and transistor Q15 becomes conductive, preventing operation of the drive circuit.

Additional related invention is the original invention patent No. 1015288 (Showa 54
This invention falls under Article 31, Item 3 of the Patent Law because it is an invention of a device that is directly used for carrying out the invention described in the first claim of 2007 Patent Application Publication No. 41682).

[Brief explanation of drawings]

Figure 1 is a partial cross-sectional perspective view of the compression device before the operation stroke for crimping a terminal, Figure 2 is a partial cross-section perspective view of the compression device shown in Figure 1 at the end of the operation stroke, and Figure 3 is a configuration diagram of the control circuit. , FIG. 4 is a detailed diagram of the control circuit. 12...Bottom plate, 20...Ram, 22.
... Dice type, 30 ... Electromagnet, 32.
...Electromagnet, 33...Switch, 50.
...Dice type, 53...Photoresponsive element, 1
12... Descending circuit, 121... Mori protection circuit.

Claims (1)

Claims: 1. A press ram carries a die for acting on a workpiece in cooperation with another die, two mutually pulling electromagnets drive said ram through a working stroke, thereby The workpiece is relatively movable to compress the workpiece between the two dies, and the control circuit controls the compression of the workpiece by controlling the energization from the power supply of the electromagnet. In the compression device, the control circuit controls the electromagnet 3.
Lowering circuit 112 adapted to limit the activation of 032 to a value that produces a small closing force: said die type 22.50
a switch 33 that deenergizes the lowering circuit 112 in response to a predetermined distance between; a force transducer 52 that monitors the force between the dice 22.50; and when the monitored force reaches a predetermined value. At times, the electromagnet 3 is activated in response to the monitored force.
A compression device comprising a force control circuit 114 for deenergizing 0.32. 2. The compression device according to claim 1, wherein one of the die molds 22.50 is mounted on a bottom plate 12 having a plurality of photoresponsive elements 53, and the light beam is directed to the photoresponsive elements. and a protection circuit 121 for generating a signal to disable the energization of the electromagnet 30,32 in response to blocking the light beam to a predetermined number of the photoresponsive elements 53. A compression device characterized by: