JP2835593B2 - Hot melt gun dispensing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed-rate discharge device for a hot-melt gun capable of discharging a fixed amount of hot-melt adhesive used for bonding various articles from a nozzle.

[0002]

2. Description of the Related Art Hot-melt adhesives are used today for box making, packaging, bookbinding, automobile parts, electric and electronic parts, woodworking, building materials,
It is widely used in the field of manufacturing sanitary products and other various products, and a bonding apparatus is used which applies the adhesive in a molten state with a wheel or discharges the adhesive from a nozzle. A hot-melt applicator system using a nozzle is generally composed of an applicator body including a melting tank, a pressure pump, a filter, a heating hose, a gun, a nozzle, and the like.

In the case of a hot melt gun, an applicator
Even if the performance is good, if the temperature control is uncertain, the viscosity of the hot melt adhesive changes, the discharge amount from the nozzle changes, and the accuracy of the pump for pumping to the nozzle and the accuracy of the pump If the rotation speed of the motor for driving the nozzle is unstable, or if dust or a degraded product of the adhesive is mixed into the adhesive to cause nozzle clogging, the discharge amount may not be constant. . Synthetic rubber-based hot melt adhesives and urethane-based hot melt adhesives that have recently started to be used are E
When the heating time is longer than that of the VA hot melt adhesive, the change in viscosity becomes large, and the heating stability is not good. Therefore, since the discharge amount is not constant, poor adhesion occurs to the whole or a part of the product. In addition, in the unmanned high-speed automatic machine using the hot melt system as described above, the post-process of the production line is greatly affected. Was causing it.

Conventionally, as a device for detecting the discharge state of a hot-melt adhesive, an optical sensor, a temperature sensor, and the like are provided for an adhesive applied linearly, dottedly, or the like to an adherend.
Devices for checking the state of the adhesive are known. However, these devices require a space for installing the device in the post-process portion of the hot melt gun, and the sensor must be correctly focused, so that when the adherend is moving, If the sensor shakes up and down, left and right, etc., it malfunctions. Also, due to the structure of the sensor, a predetermined detection angle is required and the surrounding temperature must be kept constant.
It was weak to noise, the response time was too long, spots and spots were hard to catch reliably, and adjustments of sensors and devices were difficult and one-point, and handling was troublesome as a whole. In addition, even if an abnormal discharge of the adhesive is detected as described above, the feed section of the hot melt adhesive to be supplied to the nozzle is not feedback-controlled.

[0005]

As described above, the conventional hot-melt gun is difficult to perform a fixed-quantity discharge for various reasons, and causes poor adhesion and has a great effect on an automated production line. It is an object of the present invention to provide a fixed-rate discharge device for a hot-melt gun in which the above-mentioned drawbacks are improved so that a fixed amount of hot-melt adhesive can be discharged from a nozzle.

[0006]

According to the present invention, a heater provided adjacent to a nozzle for heating a hot melt adhesive supplied to the nozzle is provided with a hot melt passing through the heater. A rotating body is provided to be rotated by the flow of the adhesive,
The rotation of the rotating body is detected outside the heater by a detecting means, and the hot-melt adhesive is applied to a nozzle based on a detection signal from the detecting means so that the rotating speed of the rotating body becomes constant. The above object is achieved by providing a fixed-rate discharge device for a hot-melt gun in which the motor rotation of a pressure-feed pump for pressure-feeding is controlled by control means.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The rotating body is located immediately before the nozzle, and is rotated by a hot melt adhesive which is heated by a heater and discharged from the nozzle. The state of discharge of the adhesive from the nozzle can be determined based on the rotation state of the rotating body, and when the number of rotations of the rotating body is less than a predetermined set value, a pressure feeding pump for pumping the hot melt adhesive to the nozzle. When the rotation speed of the motor is increased by increasing the rotation speed of the motor, and when the rotation speed of the rotating body is higher than a set value, the rotation speed of the motor of the pressure pump is reduced to reduce the flow rate, and , A fixed amount of hot melt adhesive can be discharged.

As shown in FIG. 1, a hot melt applicator (1) constituting a hot melt system includes a tank (2) for storing a molten hot melt adhesive, and a tank from the tank (2) to a nozzle. There is a pump (3) for pumping the hot melt adhesive, and a motor (4) for driving the pump (3) is provided. The pump (3) and the hot melt gun (5) are connected by a heating hose (6).

As shown in FIG. 2, the hot melt gun (5) has a nozzle (8) for discharging a molten hot melt adhesive on the side of the gun body (7). 8) is a needle valve, a rotary valve, and other well-known ON-OFF which are not shown in detail and operated by an air cylinder, an electromagnetic solenoid, or other appropriate driving means.
The above-mentioned adhesive is applied to an adherend (not shown), which is opened and closed by a valve (9) and moves below the nozzle (8), in a linear or dotted manner.

[0010] A heater (11) having a heater (10) for heating the hot melt adhesive is provided adjacent to the nozzle (8). Are two pieces (11a), (1
1b), and a connection port (12) for connecting the heating hose (6) is formed in the piece (11a).
(12) communicates with the nozzle (8) via a flow path (13). A recess is provided in the middle of the flow path (13) so as to form an enlarged detection chamber (14), and a seal piece (15) is provided on the periphery of the detection chamber.

The detection chamber (14) is provided with a rotating body (16) so as to be rotated by the flow of the hot melt adhesive passing through the heater. In the figure, the rotating body (16)
A trochoidal internal gear (1
6a) and an external gear (16b), and as shown in FIG. 3, the flow path (13) on the connection port (12) side communicates with a suction port (17) opened on the side surface of the internal and external gear, and a nozzle The flow path (13) on the (8) side communicates with a discharge port (18) opened on the side surface opposite to the suction port. And the hot melt adhesive is the suction port (17)
Flows into the space (19) between the internal gear (16a) and the external gear (16b), the internal gear (16a) is rotated in the direction of the arrow, and the adhesive is discharged from the discharge port (18) to the nozzle (8). Flows to The rotator can adopt various structures that rotate by the flow of the adhesive. For example, the rotator may be configured as a spur gear using a partition plate instead of the trochoid tooth shape, or a circumscribing gear motor. It is also possible to use a gear, an elliptical gear, a cocoon-shaped rotator, two other rotators that rotate in an appropriate engagement state, or an impeller-shaped rotator.

The rotating body (16) is provided so as to rotate lightly so as not to obstruct the flow of the hot melt adhesive. In the figure, one end of a rotating shaft (20) is supported by a bearing (21). At the other end, a ball having heat resistance and abrasion resistance, such as a steel ball, a stainless steel ball, or a ceramic ball, is brought into contact with the shaft end face, and the ball (22) is placed on a ball receiving plate (23). Although the shaft is supported, both ends of the rotating shaft may be supported by spheres or the like.

A detecting means is provided outside the heater to detect the rotation of the rotating body (16). In the figure, the detecting means is provided with an inner magnet (2) on a rotating shaft (20) of the rotating body in the heater so as to rotate together with the rotating body (16).
4), and an outer magnet magnetically coupled to the inner magnet (24).
(25) is provided on the driven body (26), and the driven body (26) is mounted on the heater.
The detection rotor (28) is provided on the driven body (26) via a shaft (27), and the detection rotor (28) is provided on the detection rotor (28). A slit or a hole is detected by a sensor (29) such as an optical sensor to generate a pulse signal. The driven body (26) is supported by a sphere (22) and a ball receiving plate (23) in the same manner as the rotating body (16), and the shaft (27) is also a ball bearing or the like. It is supported by a bearing (21).

As the detection means, various detection means can be used. For example, a magnetic sensor (not shown) can be connected to the heater section (11) without using a follower or a detection rotor. It is provided on the outside to directly detect the rotation of the inner magnet (24), or the shaft (27) is connected to the heater via an appropriate seal mechanism by omitting the follower and the inner magnet. It can extend into the negative part (11) and be directly connected to the rotating shaft (20) of the rotating body (16), or can constitute a generator to detect the number of rotations.

Based on the detection signal of the detecting means, the pressure pump (3) controls the rotation speed of the rotating body to be constant.
A control means for feedback control of the rotation of the motor (4) is provided. The control means shown in the drawing converts the pulse signal from the detection means into a current signal by a converter (30), and performs PI control on the current signal by a controller (31).
Although the frequency is converted by the inverter (32) based on the control signal to control the rotation speed of the motor (4), feedback control is performed by the PD operation or the PDI operation. Is also good.

[0016]

EXAMPLE Using a device as shown in the figure, a hot melt adhesive was injected from a hot melt gun nozzle (8) for about 1 minute 30 minutes.
When driven to discharge 30 g at a time at intervals of seconds,
Even after about 1 hour and 30 minutes from the start, as shown in FIG. 4, the ejection amount was constant within a range of 30 g ± 2 g, and it was confirmed that the ejection was constant. Such a result is almost the same for a synthetic rubber-based hot-melt adhesive or a urethane-based hot-melt adhesive, which was conventionally considered to have poor heat stability, and good results were obtained.

[0017]

The present invention is constructed as described above, and has a heater portion immediately before a nozzle for discharging a hot melt adhesive.
A rotary pump provided with a rotating body so as to be rotated by the adhesive flowing through the heater portion, a rotation of the rotary body is detected by a detecting means, and a hot melt adhesive is pressure-fed to the nozzle based on the detection signal. Since the control means is provided to control the rotation of the motor in a feedback manner, even if the viscosity of the adhesive changes on the way, the discharge amount of the hot melt adhesive actually flowing into the nozzle Can be directly checked, various hot melt adhesives can be discharged in a fixed amount, and it is possible to prevent the occurrence of defective bonding, confusion of the production line, and the like.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing the overall configuration of the present invention.

FIG. 2 is an enlarged sectional view of a part of one embodiment of the hot melt gun.

FIG. 3 is an explanatory view showing a configuration of a rotating body of the hot melt gun shown in FIG. 2;

FIG. 4 is a graph showing a discharge state of a hot melt adhesive by the apparatus of FIG. 1;

[Explanation of symbols]

1 Hot melt applicator 3 Pump
4 Motor 5 Hot melt gun 8 Nozzle
10 Heater 11 Heater part 16 rotating body
28 Detection rotor 29 Sensor

Claims (2)

(57) [Claims] A pressure pump which feeds the molten hot melt adhesive to a nozzle; and a heater provided adjacent to the nozzle for heating the adhesive supplied to the nozzle. A detecting means for detecting a rotation of the rotator outside the heater, the rotator being provided in the heater so as to be rotated by the flow of the adhesive passing through the heater; And a control means for controlling the motor rotation of the pressure feed pump based on the detection signal of the detection means so as to keep the rotation speed of the rotating body constant. Discharge device. 2. The apparatus according to claim 1, wherein said control means controls the motor of the pressure pump by an inverter.