JPH0248360B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to safety devices, and more particularly to safety devices in press machines, and in one embodiment, to safety devices in machines for attaching buttons to garments.

When moving the movable mold towards the fixed mold to process the workpiece, such as punching, drawing, caulking, swaging, etc., the workpiece must be moved by hand.
In many cases, it is necessary to insert each piece between molds and take it out from the mold after processing. In such cases, safety devices are required to avoid injury to the human body, and may be regulated by law. Many safety devices have been proposed for this purpose, but
This often impairs work efficiency, and although there is a desire for a press machine with a simple mechanism that takes sufficient safety measures without impairing work efficiency, there are few that are fully satisfactory.

Figure 1 is U.S. Patent No. 3315049, U.S. Pat.
A typical safety device in a press machine as shown in No. 21201 is shown. The press machine has a fixed mold 1 and a movable mold 2, between which a vertically slidably supported feeler rod 3 is arranged. The feeler rod 3 is normally biased upward by a spring, etc., but when the press is operated, switch SW1
When it is closed manually or with a foot pedal, it can be moved downward by a solenoid 4 or other driving means (air cylinder, etc.), and when it reaches a predetermined lowest position, it becomes a part of the feeler 3. A normally open switch whose protrusion 5 enters the power supply circuit for the power of the press machine (electric motor, air cylinder, etc.)
Close SW2. Therefore, even if the switch SW1 is closed, the feeler 3 will never close the switch SW2 as long as there is a hand or other obstacle between the molds 1 and 2, so safety is ensured. However, the problem with this safety device is that as long as switch SW1 is activated, undesired operation will occur. That is, when the switch SW1 is closed and, for example, a hand inserted between the molds is withdrawn, the feeler is immediately pulled downward, closing the power circuit, and the movable mold is driven down. For example, when attaching a button such as a snap fastener to clothing, it is necessary to hold the clothing material with your hands and keep the button stationary in a predetermined position. cannot be moved quickly to the correct position, resulting in incorrect driving or crimping. Therefore, in such a case, it is necessary to disable the power circuit, but no suitable means has been proposed.

As another method, as in Special Publication No. 55-132491,
Prepare two foot pedals or manual levers, lower the safety device feeler (similar to Figure 1) with one lever, and remove the safety device of the power means.
The other lever connects the power means to the movable mold. This is troublesome because it requires two steps of operation, and the work efficiency is greatly reduced.

The object of the present invention is to provide a safety device in a press machine that is free from the above-mentioned defects. Here, the press machine means a machine for attaching snap fasteners to clothing fabrics, a punching press, a press for drawing or bending, a press used for caulking, etc.

According to the safety device of the press machine, which will be described in detail below, a single operation of the foot pedal can confirm the safety and start the downward stroke of the plunger for the movable mold of the press. In other words, if there is a hand or other obstacle between the movable mold and the fixed mold before the plunger is started when the pedal is depressed, the feeler of the safety device detects this and activates the plunger. Prevent operation. Even if your hand is withdrawn before you return the pedal, this blocking relationship will be maintained and the plunger will not come down. This will prevent the plunger from going down unless you return the pedal completely and repeat the same operation from the beginning. This means that the ivy press operation can be prevented.

In the following, preferred embodiments of the invention will be explained in detail in conjunction with the drawings.

Fig. 2 is a side view of the snap button attachment machine equipped with the safety device of the present invention, showing the state before the pedal is depressed, Fig. 3 is a similar view after the pedal is depressed, and Fig. 4 is the pedal It is a partial front view of a state where it is depressed. The button attachment machine has an integrally molded C-shaped frame body comprising a base plate 10, a column 11, and a head 12 supported on a stand (not shown). At the front of the frame, a head 12 has a plunger 1 that moves vertically.
3 is attached so that it can be moved up and down by a power source (hydraulic cylinder or electric motor). At the lower end of the plunger 13 is an upper mold, that is, a movable mold 1.
4 is fixed, the lower end of which is adapted to receive, for example, a male or female snap button (not shown). The button may be automatically fed through the chute from a suitable automatic feeding device, or it may be inserted manually. A lower mold or fixed mold 15 is mounted in the substrate below the movable mold 14, and its upper surface is shaped to support a mounting member.

A pivot pin 16 is attached to the side surface of the rear end of the base plate 10, and a link 17 is swingably attached to the pivot pin 16, and the rear end is connected to a tension rod 19 by a pin 18. This tension rod 19 is a spring (not shown)
It is always biased upward. The lower end of the tension rod 19 is connected to a foot pedal (not shown). The left end of link 17 is connected to link 2 by pin 20.
1. The upper end of link 21 is pin 2
2 to the right end of the drive plate 23. Incidentally, the link 21 may be in the form of a nut joint having left and right threads so that its length can be adjusted. The left side of the drive plate 23 is pivotally connected to a short shaft 24 fixed to the surface of the support column 11 of the frame body. The drive plate 23 is similarly coupled to a holder plate 25, which is pivotally mounted on a shaft 24, via a friction plate 26 (made of felt, etc.) by frictional force. Details of this are shown in FIG.

As shown in FIG. 4, the driving plate 23 and the holder plate 25 have opposing planes, and a disc-shaped friction plate 26 is interposed between them. These members 23,
25 and 26 are short shafts 24 screwed into the side surfaces of the frame body.
A screw is provided on the head of the friction plate 26 by applying pressure to the drive plate 23 with a nut 28 via a spring 27.
This is done by pressing the holder plate 25 against the holder plate 25.
Therefore, the drive plate 23 and the holder plate 25 can rotate relative to each other when a force is applied between them to overcome the frictional force. Note that it is also possible as a modification to use a friction disk integrated with the holder plate or the drive plate. A guard finger or feeler 29 is fixed to the holder plate 25 and extends from there between the upper and lower dies 14, 15. The feeler 29 traverses the working area between the molds when viewed from the front of the press as shown in FIG. The feeler 29 can swing in a range from the position shown in FIG. 2 to the position shown in FIG. The upper limit of the range of movement of the feeler 29 is defined by a stop 30 or other abutment on the frame that projects from the frame, and the lower limit is defined by a stop 31 or similar abutment.

An actuator 32 protrudes from the lower end of the holder plate 25, and a pair of switches S2 and S3 are attached to the frame so as to sandwich this actuator. The positional relationship between the actuator and the switch is such that when the feeler 29 is engaged with the stopper 30, the switch S2
is closed and the feeler engages with the stopper 31, the switch S3 is set to close. A switch S1 is further supported on the frame at a position below the link 17, and can be operated by depressing the pedal.

The press having the above configuration operates as follows. Attach the specified fixtures and buttons to the upper and lower molds (generally any workpiece may be used, but for the sake of illustration, attaching buttons to clothing), support the garment fabric with your hands, and press the designated parts. Arrange them vertically,
Next step on the pedal. This pulls the tension rod 19 downward against the force of the spring, and the link 17
6 to the right (as seen in Figure 2) and push up the link 21. The link 22 thereby rotates the drive plate 23 to the left around the short axis 24, which causes the holder plate 25 to rotate to the left and drive the feeler 2.
9 to the left and push it down until it engages with the stopper 31. In the meantime, actuator 32 opens switch S2, then actuator 32 closes switch S3, and finally link 17 closes switch S1. Switch S1 engages the clutch that connects the power source to plunger 13. Figure 3 shows the plunger operating position. Lowering of the plunger occurs only when these three switches are opened and closed as described above, as described in more detail below. If you accidentally step on the pedal while your hand is on top of the lower mold 15, the front end of the feeler 29 will touch your hand during the above operation and you will not be able to lower it any further. The holder plate 25 and the drive plate 23 will rotate relative to each other, so the switch S3 will not close and the power source will not be connected to the plunger 13. Furthermore, even if you suddenly withdraw your hand from this state, the relative positions of the holder plate 25 and drive plate 23 will remain the same, so even if the pedal is fully depressed, the switch S3 will not close, so there will be no accidental descent of the plunger. After returning the pedal and returning the feeler to its original position using the stopper 30, the plunger can be reset.

FIG. 5 shows an example of a control circuit that can be used in the present invention. In the figure, R (R ₁ to R ₄ ), R′, R″, R
etc. represent relays and their contacts, and S ₁ , S ₂ , S ₃ ,
S ₁ ′, S ₂ ′, and S ₃ ′ are the contact points of the switches shown in Figures 2 and 3, S ₄ is a switch that is closed by the operation of the clutch described above, and CHC and CHC ′ are set to 0.1 seconds, for example. Connect the timer relay and its contacts,
P ₁ and P ₂ are pilot lamps, and M is a plunger actuating motor. The part related to the control of the present invention is the part indicated by C, where A is the power source circuit and B is the preliminary safety circuit. In FIG. 5, the contacts indicated by black dots are normally closed contacts, and those indicated by white circles are normally open contacts.

Now, when the press is operating, the main switch MS
is closed and the power source (motor) M is started.
The pilot lamp _P1 indicates the power connection status, and the pilot lamp _P2 indicates the operation of the motor M.
In this state, switch S2 is closed, so relay _R2 and its contacts R2 _' and _R2 '' are working.
As explained in connection with FIG. 4, when the pedal is depressed, switch S2 opens, but the circuit through normally closed contact S ₁ '-relay contact R ₂ '-relay R ₂ is maintained. Next, when switch S3 closes, power flows through the held relay contact R ₂ ″ - relay R ₃ ,
It is held by relay contact R' ₃ and continues to be held even if normally closed contact S ₁ ' opens and relay R ₂ becomes inactive.
Next, when the switch S1 closes, the normally closed contact _S1 ' opens, but since the relay contact _R3 '' is held by the relay contact _R3 ', current flows to the relay _R4 and connects the clutch through the contact _R4 '. Current flows through the solenoid SOL, connecting the clutch to the plunger 13 and causing the plunger 13 to enter a predetermined downward stroke.At the same time, the normally closed contact S ₄ ' is opened, the control circuit is restored, and the normally open switch for the timer circuit is opened. S4 closes.

The above is a case of normal operation, but if the finger or feeler 29
If it is touched by a hand or the like, the feeler 29 does not descend, but only causes a relative movement between the holder plate 25 and the drive plate 23. Then, even if switch S2 opens and S1 closes, the circuit passing through relay _R3 will not operate, so relay _R4 will also not operate.
Solenoid SOL doesn't work either. Also switch S
Even if relay 3 is closed after S1, the normally closed contact S ₁ ' is already open, so the circuit of relay R ₃ will not operate. Therefore, the safety device will not actuate the clutch transmitting power to the plunger unless the pedal is released to return the feeler 29 to the starting position of FIG.

In addition, if the tension pin of the solenoid SOL breaks due to some accident after the clutch is engaged, the clutch will remain engaged regardless of the circuit operation, and the plunger will continue to move up and down, which is dangerous. be. As a countermeasure to this, a timer CHC is used to close the normally open switch contact S4 in conjunction with the clutch. If switch S4 does not open after 0.1 seconds, the timer contact
CHC′ closes, relay R ₁ operates to hold relay R ₁ at its contact R ₁ ′, and opens the closing contact R ₁ ″ of the motor. Thus, the plunger lowers and rises only once with each pedal operation. .

As described above, according to the present invention, since the feeler is associated with pedal operation through the connection of the holder plate and the drive plate, when a hand or other object is present between the press dies, the operation of the press is blocked, and the hand Even if the machine or object is retracted, the press will not operate, which prevents the possibility of incorrect operation. Moreover, the pedal only needs to be operated once, and there is no need to operate two switches sequentially with the foot or hand, resulting in high work efficiency.
It will be apparent to those skilled in the art that many variations are possible within the scope of the invention.

In short, the main point of the present invention is to control the operation of switch S3 depending on the presence or absence of obstacles between the molds by using a frictionally coupled holder plate and drive plate, thereby providing a safety measure and The plunger cannot be driven unless the driving plates are positioned relative to each other. Therefore, the circuit configuration may be other than that shown in FIG. 5.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the safety device of a conventional press machine, Fig. 2 is a side view of a press machine having the safety device of the present invention, and Fig. 3 is similar to Fig. 2, showing a state in which the pedal is depressed. FIG. 4 is a side view, FIG. 4 is a front view seen from the left of FIG. 3, and FIG. 5 is a diagram showing an example of the control circuit. The main parts in the diagram are as follows. 10: Substrate, 11:
Post, 12: Head, 13: Plunger, 14:
Movable type (upper type), 15: Fixed type (lower type), 17,1
9, 21: Link, 23: Drive plate, 25: Holder plate, 26: Friction plate, 29: Feeler or guard finger, 30, 31: Stopper, 3
2: switch actuator, S1, S2, S3: switch.

Claims (1)

[Scope of Claims] 1. A safety device for a press machine in which a movable mold supported by a power-driven plunger and a fixed mold aligned opposite to the movable mold are supported on a frame, in which a safety device is provided between the molds. a pivotable holder plate supporting the feeler, a stopper defining a pivot range between the upper and lower limits of the feeler and the holder plate, and a pivot frictionally coupled to the holder plate directly or via a friction plate. a movable drive plate, a pedal connected to said drive plate via a linkage, the pedal being adapted to pivot said drive plate on operation thereof, at said lower limit a part of said feeler or holder plate; 1. A safety device for a press machine comprising: a control switch actuated by said control switch; and means for coupling a power source to said plunger upon actuation of said control switch. 2. The circuit coupling power to the plunger includes a first switch having contacts that close at the upper limit of the feeler and a second switch that closes later than the control switch at maximum depression of the pedal;
2. A safety device for a press machine as claimed in claim 1, wherein the circuit for coupling power to the plunger is completed only by sequential closure of the control switch and the second switch.