JPH0581536B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a gob weight control method in an IS type glass bottle forming machine.

(Prior Art) An IS type (independent section type) glass bottle forming machine is a typical glass bottle forming machine that connects in series a number of forming sections of the same structure that are operated with a predetermined phase difference, and has a common gob feeder. Glass bottles are formed by sequentially distributing gobs continuously supplied to each section.

However, the weight of the gobs supplied from the gob feeder may fluctuate due to various external disturbances.
If the gob is too heavy than the design value of the mold, it will cause defects such as protrusion at the mouth of the glass bottle, and on the other hand, if the gob is too light than the design value of the mold, it will not protrude enough at the mouth of the bottle or cause problems such as mouth flow. will occur. For this purpose, conventionally, the operator of the glass bottle forming machine measured the gob weight using a scale at regular intervals, and controlled the gob weight by changing the tube height of the gob feeder by operating the handle. Ta.

Recently, as shown in Japanese Patent Publication No. 59-43426, for example, the maximum stroke of the plunger that press-forms the gob is detected by a sensor such as a differential transformer, the weight of the gob is measured, and the weight of the gob is determined based on this value. Attempts have also been made to automatically control the gob weight by automatically changing the tube height of the gob feeder.

However, with such conventional automatic gob weight control methods, the detection accuracy of the plunger's maximum stroke was low, and the gob weight control accuracy was about ±0.5%.
A variation of 0.75 g can occur for a glass bottle of g. Converting this to glass capacity is approximately 2.0cc, and for this reason, it is necessary to increase the inner diameter of the straight part of the glass bottle mouth to absorb fluctuations in gob weight. It was not possible to press-blow mold glass bottles.

(Problem to be solved by the invention) The present invention solves the above-mentioned conventional problems and
The fluctuation in the weight of the gob supplied to the glass bottle molding machine has been suppressed to less than half that of the previous model, and it is now possible to mold glass bottles with narrow openings with an inner diameter of approximately 10 mm, which was previously impossible to press blow mold. This was completed in order to provide a method for controlling gob weight in a glass bottle forming machine.

(Means for Solving the Problems) The present invention aims to solve the above problems by controlling the displacement of a conductor attached at a constant pitch to the movable side of the plunger of each section of an IS type glass bottle forming machine to the fixed side. By detecting it as the secondary output of the coil that is excited by the primary AC signal attached to the
The maximum stroke of the plunger of all sections of the IS type glass bottle forming machine is continuously taken out, the average deviation for a predetermined number of times is converted into a gob weight deviation, and the set value of the tube height of the gob feeder is constantly adjusted by PI control. The tube height is adjusted by rotating a motor based on this signal.

The present invention will be explained in more detail below with reference to illustrated embodiments.

(Embodiment) FIG. 1 is a perspective view schematically showing the entire embodiment of the present invention, in which two 6-section IS-type glass bottle forming machines 1, 1 are arranged in series, and substantially 12 An example of operation as a section forming machine is shown.

Sensors, which will be described later, are attached to the forming member operating devices of all sections of each glass bottle forming machine 1, and information from the sensors is inputted to the control panel 3 through the sensor interface box 2. Further, the control panel 3 displays necessary information on the operator terminal, and allows necessary instructions to be given and controlled to the system through the control panel 3 or the operator terminal.

The glass bottle forming machines 1, 1 are for forming glass bottles by a press blow method, and the operation is detected by a plunger for press forming gobs supplied from a gob feeder 4 among the forming members inside a rough mold. A sensor is installed.

FIG. 2 is a diagram showing the specific structure of the sensor, in which 5 is a piston rod for raising and lowering the plunger;
6 is a cylinder on the fixed side. A ring-shaped conductor 7 is attached to the surface of the piston rod 5 at a constant pitch, and a coil 8 is attached to the cylinder 6. The structure and operating principle of this sensor are as follows.

That is, as shown in FIG. 3, the coil 8 includes primary coils 9a to 9d and secondary coils 10a to 10d, and the cylindrical spaces of these coils are concentric with the piston rod 5. The conductor 7 is made of a better conductor than the material of the piston rod 5, and may be made of aluminum, copper, etc., and its surface may be coated with another material.

The coil 8 operates in four phases, A, B, C, and D, as exemplified by the primary AC signal.
The magnetic resistance is shifted by 90° depending on the relative position of the conductor 7 with respect to the coil. For example, if phase A is a cosine phase, phase B is a sine phase, and phase C is a sine phase.
The phase is arranged to be a minus cosine phase, and the D phase is arranged to be a minus sine phase.

In the embodiment, the primary coils 9a to 9d and the secondary coils 10a to 10d of each phase are wound at the same position, and the length of each coil is P/2 (P is an arbitrary number).
It is. The A-phase and C-phase coils, and the B-phase and D-phase coils are provided adjacent to each other, and the interval between each coil group is [P×(n+0.25)] (n is any natural number).

In the above configuration, each phase primary coil 9a~
The magnetic flux caused by 9d passes through the piston rod 5, and when the conductor 7 enters the magnetic field, an overcurrent flows along the ring-shaped conductor 7 depending on the amount of penetration. As a result, an overcurrent flows through each conductor 7 depending on the degree of penetration of the conductor 7 into the primary coil of each phase, and a change in magnetic resistance due to this overcurrent loss occurs in the magnetic circuit of each phase. The secondary coils 10a to 10d of each phase are excited with an alternating current signal at a level corresponding to this magnetic resistance.

In this embodiment, an output signal corresponding to the linear position of the piston rod 5 is obtained by a phase shift method. That is, in each phase, the piston rod 5
A periodic change in magnetic resistance occurs depending on the linear displacement of the phase, and the phase of this change in magnetic resistance is 90° between adjacent phases.
It is shifted by degrees (P/4). Therefore, if the phase angle corresponding to the linear displacement is expressed as φ, the level of the voltage excited in the secondary coils 10a to 10d of each phase depends on the linear position (that is, φ) of the piston rod 5, and in the A phase, cosφ, sinφ for the B phase, −cosφ for the C phase, and −sinφ for the D phase (however, 2π corresponds to P). The A-phase and C-phase primary coils 9a, 9c are excited by a sine wave signal sin ωt, and the B-phase and D-phase primary coils 9b, 9d are excited by a cosine wave signal cos ωt. Then, the output signals of the secondary coils 10a and 10c are added differentially, the output signals of the secondary coils 10b and 10d are also added differentially, and the differential output signals of each phase are added and synthesized to form the final An output signal Y is obtained. Then, the final output signal Y can be expressed by the following equation.

Y=sinωt cosφ−(−sinωt cosφ)+cosωt s
inφ−(−cosωt sinφ) =2sinωt cosφ+2cosωt sinφ=2sin(ωt+
φ) Here, φ corresponds to the linear position of the piston rod 5, so by measuring the phase shift φ of the output signal Y corresponding to the primary alternating current signals sin ωt, cos ωt using a known phase difference detection circuit, the piston rod 5 can be determined by can accurately detect the position of

The phase shift data Dφ obtained in the above manner is the length P of one cycle of the periodic pattern of the conductor 7.
The absolute position of the piston rod 5 is shown within the range of . The current position of the piston rod 5 with respect to the predetermined origin position is based on this phase shift data Dφ, and data Dx indicating the number of cycles from the origin position of the conductor 7 currently entering the coil 8.
It can be specified in combination with Note that the signal processing method is not necessarily limited to the phase shift method. By the above method, it is possible to accurately measure the absolute position of the forming member actuating device such as the piston rod 5 in all sections of the IS type glass bottle forming machine on the order of 1 μm.

FIG. 4 is a graph showing the operating curve of the piston rod 5 electrically removed during glass forming in this manner. The highest point in this graph indicates the maximum stroke position of the plunger, and since glass is an incompressible viscous fluid, if the volume of the rough mold is constant, the maximum stroke position of the plunger is the weight of the gob. is directly expressed.

FIG. 5 is a block diagram illustrating the gob weight control method of the present invention.

The maximum stroke value of the plunger taken out from each section as described above is input one after another into the memory 11 provided corresponding to each section. In the embodiment, the memory 11 can store 20 consecutive pieces of data regarding the same plunger, and as new data is input, the oldest data is sequentially erased. Then, the average value of the 20 pieces of data inside the memory 11 is calculated. Compare this with the set value of the maximum stroke position of the plunger, calculate the position deviation ΔP for each plunger, and calculate the average position deviation ΔB of all sections for each sampling time set to a value of 99 seconds or less. . Next, from this average position deviation ΔB, ΔG = (D/2) ²・π・
The gob weight deviation ΔG is calculated based on the formula C·ΔB. Here D/2 is the radius of the plunger, C
is the specific gravity of glass.

Next, the gob weight deviation ΔG obtained in this way
is a parameter, and inside the gob weight control unit
The set value L of the tube height of the gob feeder is calculated by PI control. To do this, perform the calculations shown in block 12 of Figure 5, and
The positioning amount ΔS is first calculated by control. Then, the tube height l at the time of calculating the set value is added to this positioning amount ΔS, and the set value L of the tube height is calculated as L=l+ΔS.

The gob weight control unit adjusts the tube height by rotating the stepping motor 13 shown in FIG. 6 based on the tube height setting value L calculated in this way. As shown in Figure 6,
The stepping motor 13 is configured to drive a shaft 15 for raising and lowering the tube via a reduction gear 14 and an electromagnetic clutch 15, and the upper end of this shaft 15 rotates a feed screw to raise and lower the tube 16 of the gob feeder 4. let Further, a rotation angle sensor 17 is attached to the lower end of the shaft 15 to detect the height of the tube 16. The sensor 17 for this purpose can be based on the same principle as the sensor for detecting the plunger height described above, but is not necessarily limited to this. The electromagnetic clutch 15 described above is used to disconnect the stepping motor 13 from the shaft 15 when the operator manually drives the shaft 15.

In this way, the height of the tube 16 is constantly controlled based on the gob weight data that is input one after another from the sensor attached to the piston rod 5 of the plunger of each section of the IS type glass bottle forming machine, and the gob weight is This means that the control will be much more precise than before.

(Effects of the Invention) As explained above, according to the present invention, the displacement of the conductor attached at a constant pitch to the plunger of each section of a glass bottle forming machine is excited by the primary AC signal attached to the fixed side. By detecting the secondary output of the coil, the maximum stroke of the actually formed plunger can be determined in micrometers much more accurately than the conventional measuring method using a working transformer.
Can be accurately measured to order.

Moreover, in the present invention, based on this measured value, calculation processing such as calculating the average deviation of the maximum stroke of the plunger, converting it to a gob weight deviation, and calculating the set value of the tube height of the gob feeder using PI control is performed, and this signal is used. Since the tube height is controlled by driving the stepping motor based on this, the average value of the gob weights supplied to all sections of the glass bottle forming machine can be accurately adjusted to the design value. As a result, with the present invention, it is possible to control the gob weight with an accuracy of ±0.25%, and the absorption allowance for fluctuations in the gob weight can be reduced. It becomes possible to form glass bottles of

Furthermore, according to the present invention, when an obvious molding abnormality is detected, an alarm signal or a stop signal can be issued, and the glass bottle molding process, including the control of gob weight, which was conventionally managed by the skill of the operator, can be performed. can be managed more scientifically.

Therefore, the present invention makes an extremely large contribution to the industry as a gob weight control method in a glass bottle forming machine that solves the conventional problems.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing the entire embodiment of the present invention, FIG. 2 is a sectional view showing the specific structure of the sensor, and FIG. 3 is an enlarged sectional view showing the structure and operating principle of the sensor. Fig. 4 is a graph showing the operating curve of the plunger electrically taken out during glass forming, Fig. 5 is a block diagram explaining the gob weight control method of the present invention, and Fig. 6 is a tube height control device. The front view shown in FIG. 7 is a block diagram of the entire control system of the glass bottle forming machine. 1: Glass bottle forming machine, 4: Gob feeder, 5:
Piston rod for plunger operation, 6: cylinder, 7: conductor, 8: coil, 9a to 9d:
Primary coil, 10a-10d: Secondary coil, 1
3: Motor.

Claims (1)

[Claims] 1 Detecting the displacement of the conductor attached at a constant pitch to the movable side of the plunger of each section of the IS type glass bottle forming machine as the secondary output of the coil attached to the fixed side and excited by the primary AC signal. The maximum stroke of the plunger of all sections of the IS type glass bottle forming machine is continuously taken out, the average deviation for a predetermined number of times is converted into the gob weight deviation, and the set value of the tube height of the gob feeder is calculated using PI control. A method for controlling gob weight in a glass bottle forming machine, characterized in that the height of the tube is adjusted by constantly calculating the signal and rotating a motor based on this signal.