JPH0676103B2 - Screw type cap tightening method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cap tightening method in a capping device that uses a screw-type cap made of metal, resin, or the like, and each head is equipped with a motor that is rotationally driven independently. Applied to the capping device.

[Conventional technology]

In FIG. 7, (01) is a container gripping mechanism including a pair of arms (03), (03) for holding the body of the container (02),
A plug gripping mechanism (05) for gripping the plug (04) is provided above the container gripping mechanism (01), and the plug gripping mechanism (05) is linked to a torque motor (07). The torque motor (07) is fixed to the upper end of the tubular body (08), and the tubular body (08) can be moved up and down by an elevator mechanism (not shown).

The rotary shaft (010) that rotates the plug gripping mechanism (05) and the drive shaft (011) of the torque motor (07) are the same as the drive shaft (0
A slit (013) is formed along the axial direction on the inner surface of the tubular coupling fitting (012) fixed to (11), and this slit (013)
A key (014) fixed to the upper end of the rotary shaft (010) is slidably engaged with the rotary shaft (010) to allow the rotary shaft (010) to move up and down with respect to the coupling fitting (012) while allowing the torque motor (0
The rotation of 7) can be transmitted to the plug gripping mechanism (05). In addition, the stopper ring (0
15) to prevent this.

The plug gripping mechanism (05) is basically the same as the one that grips the plug (04) by utilizing the air pressure known as a conventionally known air chuck, and the air pressure is applied to the pressure chamber (020). By introducing the disk (021), the ring-shaped elastic body (022) is elastically deformed, and the elastic body (022).
(04) A plug inserted into the shaft hole by shrinking the inner diameter of the shaft hole (04)
Is to hold. The pressure chamber (020) is connected to the compressed air source (028) via the air passages (023), (024), (025), the conduit (026) and the solenoid valve (027). The space on the upper surface of the stopper (04) is covered with the elastic body (022).
When 4) is gripped, it is sealed by the elastic body (022), so that the space is made to communicate with the atmosphere through the passages (029) and (030).

However, (035) is the controller (036) that occupies the main part.
And a detector (034), a comparator (037), and a torque setting device (038), wherein the controller (036) is
The rotation speed of the torque motor (07) is controlled to a required rotation speed by receiving a signal from the tachogenerator or the rotary encoder (039), and the torque of the torque motor (07) is controlled, and the solenoid valve (027). Solenoid (040)
The solenoid valve (027) is opened and closed by controlling the energized state of. On the other hand, the torque setting device (038) sets the maximum value of the closing torque, and the comparator (037) detects the current or voltage value corresponding to the set torque value set in the torque setting device (038) and the above detection. The current or voltage value of the torque motor (07) detected by the device (034) is compared, and when the detected value exceeds the set value, this is input to the controller (036).

It is also possible to provide a torque detector (041) on the rotary shaft (010) instead of the detector (034) and directly detect the torque value applied to the rotary shaft (010) by the torque detector (041).

In such a device, the main body (08) is located at the rising end, and therefore the torque motor (07) and the plug gripping mechanism (05) are arranged.
The controller (036) drives the torque motor (07) to rotate at a low torque and a required number of revolutions in a state in which the above components are located at the rising end. In this state, like the conventionally known capper, when the container (02) is introduced into the container gripping mechanism (01), the container gripping mechanism grips the container (02) and the stopper (04) is elastic. When it is inserted into the shaft hole of the body (022), a signal from a sensor (not shown) that detects the operation of the body (022) is transmitted to the controller (03
6), the solenoid (040) is excited to open the solenoid valve (027). As a result, the air pressure from the compressed air source (028) is introduced into the pressure chamber (020), so that the elastic body (022) holds the plug (04) as described above.

Next, when the main body (08), the torque motor (07), the plug gripping mechanism (05), etc. are integrally lowered by an elevator mechanism (not shown), the mouth of the container (02) is relatively inside the plug (04). Is inserted into the container (02), and the stopper (04) is rotated to turn the stopper (04) into the container (02).
Is screwed onto. When the rotation of the stopper gripping mechanism (05) and the torque motor (07) decreases or stops, the rotary encoder (039) detects this and the controller (036)
Increases the current and / or voltage to the torque motor (07) to increase its output torque, and the plug gripping mechanism (0
Increase the capping torque of the stopper (04) by 5). When a signal from the comparator (037) detects that the capping torque exceeds the current or voltage value set by the torque setting device (038), the controller (036) stops the increase of the output torque and , The solenoid (040) is deenergized to release the grip of the stopper (04) by the elastic body (022).

After that, the main body (08), the torque motor (07), the plug gripping mechanism (05), etc. are lifted to the original rising end position by the lifting device, and the controller (036) increases the rotational speed of the torque motor (07). The output torque of the torque motor (07) is reduced in accordance with. On the other hand, the container (02) with the stopper (04) tightened is released from the container gripping mechanism (01), carried out to the outside, and conveyed to the next step.

Torque motor (0) increased by the controller (036)
If the signal from the comparator (037) is not obtained even when the output torque value of 7) reaches the maximum value, the controller (036) activates an alarm device (not shown), and also the container gripping mechanism (01) After releasing the grip of the container (02), an appropriate discharging mechanism (not shown) is operated to prevent the container from being discharged from the processing line and conveyed to the next step.

[Problems to be solved by the invention]

(1) A known method in which the speed immediately before the final closing is detected, the torque (voltage or current) generated in the torque motor from the cap side is maintained as it is, and the closing is completed with the set value of the torque setting device. Then, the torque and the rotation speed applied in the process from the beginning of the closure to the completion of the final closure cannot be sufficiently controlled.

In other words, due to the diversification of product containers with screw-type caps, the material of the seal cap attached to the screw-type cap and the cap, the screw part, the shape of the seal packing material, the material of the container to be screwed, the container screw part Shape, cap at the time of sealing, environmental conditions of the screw part of the container (temperature,
A desired capping torque value or capping torque value is quantitatively strictly required in accordance with humidity, dryness, etc.). However, conventional methods cannot meet those strict requirements.

(2) Since the friction torque of the rotating portion and the rotating shaft system cannot be avoided due to the function of the capping tightening device, this friction torque greatly affects the capping torque value given by the torque motor.

(3) With respect to the above problem, the degree of influence is different among the plurality of heads arranged, and as a result, a uniform capping torque cannot be obtained between the capping product containers.

(4) Similar to the friction torque, the inertial force due to the inertial moment of the rotating shaft system cannot be avoided, so the capping torque value is affected by the inertial force due to the rotating shaft system in the process up to the final closing. With respect to the problem of the item (1), the capping container cannot obtain a uniform capping torque value.

[Means for solving problems]

(1) Each setting device for setting the output torque and the rotation speed of the torque motor is provided.

(2) Provide a reference torque setting device that quantitatively sets the friction torque of the rotating shaft system (a slightly large torque value can be set).

(3) A comparison circuit for adding / subtracting between the motor output torque value from the torque motor and the reference torque value of the reference torque setting device is provided.

[Work]

(1) With the output signal from the comparison circuit, the value of the output torque setting device is switched by the voltage switching device via the timer, and the torque of the torque motor is controlled by the torque variable motor controller.

(2) The speed control is performed independently based on the same idea as the torque control.

(3) When the speed of the torque motor is changed, particularly when the speed is changed to a speed lower than the speed change, the inertial force due to the inertia moment of the rotary shaft system is absorbed by the regenerative energy of the torque motor to minimize the influence of the inertia moment.

〔Example〕

In FIGS. 1 and 2, (3) is an upper cam support fixed to the support column (2), and (4) is the upper cam support (3).
An upper annular rail having a cam groove secured to it by bolts or the like, (5) is a turntable, and the turntable (5) is fitted to the support sleeve (1) and is connected to a drive device (not shown). There is. Further, (50) is a turret hub (mounting member) fixed to the turntable (5), (7) is a bottle gripping device, and the bottle gripping device (7) is mounted on the turntable (5). Has been done. Further, (90) is a bottle having a spiral groove on the outer circumference of the bottle mouth,
It is held by the bottle gripping device (7). (12) is a lower annular rail having a cam groove fixed to the fixed hub (49) by a bolt or the like, and (15) is a cam floor having two rolls of a large size and a small size engaged with the cam groove of the upper annular rail (4). A plurality of cam floors (15) are arranged on the circumference of the turret.

A plurality of turret frames (51) fixed to the outer peripheral portion of the turret hub (50), a turntable (52) pivotally supported by the columns (2) and fixed to the turret frame (51), (53) is a sleeve fixed to the turret table (52), (54) is a turret frame fixed to the sleeve (53) while being supported by the column (2), and (55) is a turret frame (54). O-ring that seals between the column and the column (2), (56) is a slip ring mounted between the turret frame (54) and the column (2), and (57) is the turret table (52). In a torque variable motor such as a fixed servo motor, a control cable is wired to a control panel (not shown) via a slip ring (56) (a control circuit will be described later).

Further, (57 ') is a timing pulley fixed to the output shaft of the motor (57), (26) is a cylinder suspended and supported by the cam floor (15) and loosely fitted in the turret frame (54), (59). ) Is a piston fitted into the cylinder (58), (60) is a cap fixed to the cylinder (58) by bolts, etc., (61) is a housing fixed to the piston (59) by penetration, (62) Is a compression coil spring, which gives repulsive force to the piston (59) in the cylinder (58), (63)
Is fixed to the cylinder (58) and is engaged with the groove of the turret frame (54), (64) is an O-ring for sealing between the cylinder (58) and the housing (61), (65) Is an O-ring that seals between the cylinder (58) and the piston (59), (66) is an O-ring that seals between the piston (59) and the housing (61), and (67) is a housing (61). A shaft screwed on, a slider (68) engaged with the turret frame (51),
An air passage (flexible hose) (69) extending from the cylinder (58) to the top of the column (2), and a spindle (70) loosely fitted to the shaft (67) and fitted to the bearing (22). Sleeve, (71) is a key fixed to the spindle sleeve (70), (72) is the spindle sleeve (70)
A timing pulley fixedly attached to the base, an endless timing belt (73) stretched between a pulley (57 ') and a pulley (72), and an endless timing belt (83) supported by a base (82). The pivot arm, (84) is the pivot arm (8
A cam roller pivotally supported by 3), (85) an open arm fixed to the shaft of the pivot arm (83), (86) a chucking block, and a range of an elongated hole formed in the base (82). Is mounted so that it can be moved vertically. Further, (87) is a compression coil spring interposed between the base body (82) and the chucking block (86), (88) is a chucking arm built in the chucking block (86), and (89). ) Is a vertically movable sensor (round bar with a step) built in the chucking block (86), and (90) is a screw cap type bottle having a screw groove formed on the outer periphery of the bottle mouth. Further, (91) is a screw cap in which a screw groove is formed, (92) is a screw cap head, and each part (82) to (86) is incorporated. (93) is a spindle coarse solid.

Next, the control circuit shown in FIGS. 3 and 4 will be described.

The torque variable motor controller (101) can change the motor rotation speed of the torque variable motor (57) by changing the voltage of the command voltage V ₂ , and the motor of the torque variable motor (57) by changing the voltage of the command voltage V _1. The output torque can be changed. Further, T ₃ is the motor output torque value of the variable torque motor (57) (the motor output torque is replaced by the voltage).

Variable torque motor (57) and variable torque motor controller (10
A slip ring (56) is connected between 1) via an electric wire (108).

The setting of the command voltages V ₁ and V ₂ to the variable torque motor controller (101) and the incorporation of the output torque T ₃ from the same controller (101) are performed by the controller (inside the chain double-dashed line) (109). Be done.

Next, the configuration of the controller (109) will be described.

(111) is a first motor output torque setting device, which is composed of a variable resistor (VR ₁₁ ), and is connected to the torque variable motor controller (101) via the voltage switching device (102) to the first motor output torque setting value T ₁₁ To set.

(112) is a second motor output torque setting device, which is composed of a variable resistor (VR ₁₂ ), and is connected to the torque variable motor control device (101) via the voltage switching device (102) to the second motor output torque setting value T ₁₂ To set. (T ₁₁ > T ₁₂ is set.) (121) is the first motor rotation speed setting device, which is a variable resistor (V
R ₂₁ ), and sets the first motor rotation speed setting value N ₁₁ in the torque variable motor controller (101) via the voltage switch (103).

(122) is a second motor rotation speed setting device, which is a variable resistor (V
R ₂₂ ) and sets the second motor rotation speed set value N ₁₂ of the torque variable motor controller (101) via the voltage switch (103). (N ₁₁ > N ₁₂ is set.) (131) is a reference torque setting device, which is composed of a variable resistor (VR ₃₁ ), and has a reference torque value T ₂ of the comparison circuit (104) (in this embodiment, the rotary shaft). It is a setting device that sets the friction torque of the system to a value slightly larger than that.

Reference numeral (102) is a voltage switching device, which receives a setting signal T ₁₁ from the first motor output torque setting device (111) and a setting signal T ₁₂ from the second motor output torque setting device (112) to rotate the timer (105).
The command voltage V ₁ is set in the torque variable motor controller (101) by switching the output signal from the.

(103) is a voltage switching device, which is a first motor rotation speed setting device (1
21) setting signal N ₁₁ from the second motor rotation speed setting device (1
The setting signal N ₁₂ from 22) is switched by the output signal from the comparison circuit (104) to set the command voltage V ₂ to the torque variable motor controller (101).

(104) The comparison circuit compares the reference torque setting unit and the reference torque value T ₂ which is set at (131), and a motor output torque value T ₃ from the variable torque motor controller (101), T ₃ > T
_When it reaches ₂ , it outputs a signal.

Reference numeral (105) is a timer circuit, which is delayed by the output signal of the comparison circuit (104) from the voltage switch (103) and which has a voltage switch (1).
02) is output (the delay time is determined by the volume inside the timer circuit. In this embodiment, 50 msec to 1000 msec).

Next, the operation of this device will be described.

The rotation of the screw cap head (92) is performed by transmitting the rotation of the motor (57) to the pulley (72) via the pulley (57 ') and the belt (73), and is controlled separately from the turntable (5). To be done.

When the screw cap head (92) descends, the sensor (89) contacts the screw cap (91) previously mounted on the bottle (90) to detect the presence or absence of the cap. If the cap (91) is not provided, the position of the sensor (89) with respect to the chucking arm (88) does not change, and the chucking arm (88) maintains the open state and does not come into contact with the bottle (90). On the other hand, when the cap (91) is provided, the relative position of the sensor (89) with respect to the chucking arm (88) changes, and the chucking arm (88) is closed by the elastic force of a spring device (not shown). The closing timing is immediately after the chucking arm (88) presses the upper surface of the screw cap (91) by the elastic force of the spring (87).

The rotating chucking arm (88) closes,
When the outside of the screw cap (91) is gripped, the gripped cap (91) is rotated by the torque variable motor (57) and tightened according to the spiral formed on the bottle (90).

When the tightening is completed, the conical cam (27) descends with respect to the screw cap head (92), and the cam roller (84) that compresses the conical cam (27) rotates the pivot arm (83), so that the open arm (85) is released. The capping arm (86) is opened, and the grip of the screw cap (91) is released.

In the next step, the bottle with the cap tightened is discharged, and the subsequent steps are the same as those in the related art, and detailed description thereof will be omitted.

Next, the cap tightening control will be described in detail with reference to FIGS. 1 to 5.

The cap (91) gripped as described above is rotated by the torque variable motor (57) set to the motor output torque T ₁₁ and the motor rotation speed N ₁₁ , and starts to be tightened.
1) and cap (9) along the spiral formed on the bottle (90)
Torque is generated by the friction between 1) and the bottle (90), and the torque variable motor (57) increases the motor output torque from point S in FIG. As a result, the motor output torque value T ₃ also becomes large. A reference torque value T ₂ (for example, slightly larger than the friction torque of the rotary shaft system) is preset in the comparison circuit (104) via the setting device (131). When the motor output torque value T ₃ reaches T ₃ ≧ reference torque value T ₂ at the point A, a signal is input from the comparator (104) to the voltage switch (103), and the high speed first motor rotation speed setting value N ₁₁ To the low speed second motor rotation speed setting value N ₁₂ .

On the other hand, when the time TR set in the timer circuit (105) has passed, a signal is input to the voltage switch (102) to switch from the first motor output torque value T ₁₁ to the second motor output torque value T ₁₂ (= 0). At the same time, the second motor rotation speed setting value N ₁₂ is also switched to 0. From the switching point Q, the inertial force due to the inertia moment of the rotary shaft system of the torque variable motor (57) is absorbed by the regenerative braking energy of the torque variable motor (57) until the closure is completed, and the influence of the moment of inertia is minimized. To do.

That is, in general, the friction torque of the rotary shaft system of the cap tightening device becomes a value of 1/3 to 1/5 of the capping torque, and when the capping torque is practically applied by the torque variable motor, the tightening torque is set to the reference set torque and tightening torque. Since the set torque width can be made large, the torque motor can sufficiently respond even if the rotation setting control is performed.

In addition, the setting of the rotation speed can exhibit the same characteristics.

Next, the operation of the timer (105) will be described. Both the torque and the rotation speed have setting devices and corresponding voltage switching devices, and a comparison circuit (104) between V ₁₁ and V _{12 and} between V ₂₁ and V ₂₂ is provided. ) Is used for switching, and the timer (105) has the function of changing the timing of switching.
The purpose is to give a uniform capping torque and capping torque. In the process from the beginning of capping to the completion of final capping, the combination of controlled torque and rotational speed is important in cap tightening control. The tightening torque immediately before, that is, when the rotational speed is low is the most important.

Therefore, the following tightening control method is also possible by inserting the timer (105) into the set torque voltage switching circuit.

FIG. 6 shows a control pattern in another embodiment, in which each torque setting value is set as follows: reference torque setting value T ₂ <first motor output torque setting value T ₁₁
<Second motor output torque setting value T ₁₂ or each rotation speed setting value is set as follows: First motor rotation speed setting value N ₁₁ > Second motor rotation speed setting value N ₁₂ Torque variable motor (57) When the equipped capping head starts to close the cap, the torque monitor value from the variable torque motor controller (101), that is, the motor output torque value T ₃ becomes large, and when the reference torque value T ₂ exceeds the point A, The comparison circuit (104) operates and the torque variable motor (5
The rotation speed of 7) is switched from the first speed N ₁₁ to the second speed N ₁₂ . However, since the torque motor output torque of the capping head is set at the first motor output torque setting value T _{11, the} capping is stopped until the torque setting value T ₁₁ (the output torque of the torque motor is regulated at T _11). Therefore, the motor stops at the point (point P) in equilibrium with the cap closing torque). The timer (105) is operated from the operation of the comparison circuit (104), and at the time Q when the time is up, the output torque of the torque motor is switched to T ₁₂ , so that the capping head starts capping again and the capping torque is the torque motor set value T. ₁₂
The capping is completed at the point when the value reaches.

By adjusting the time TR of the timer circuit as described above, the cap closing can be temporarily tightened with the first motor torque setting value, and the cap closing specified torque can be tightened with the second motor torque setting value. At this time, when switching to the second motor torque set value T ₁₂ , the motor always starts from the stopped state, so the rotation speed when the cap is closed is low,
Moreover, since it is stable, it is possible to minimize the variation in the closing torque.

The command voltages V ₁ and V ₂ may be replaced by current values.

Further, as the motor output torque setting value and the motor rotation speed setting value, two examples of high and low values are shown, but the same applies to three or more types.

〔The invention's effect〕

(1) The rotation speed and the torque are appropriately combined and controlled in the process up to the completion of the capping, and the target uniform capping torque and capping torque of the screw bottle product can be obtained.

(2) By using the comparison circuit (104) and the timer circuit (105), it is possible to increase the combination of the rotation speed and the torque in the above item (1), and perform fine capping control.

(3) The rotational speed can be switched so that the inertial force due to the moment of inertia of the drive shaft system is absorbed by the regenerative energy of the torque motor, and the influence of the inertial force on the closing torque can be minimized.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a screw type capping device for carrying out the present invention, FIG. 2 is an explanatory view showing a capping state of the device shown in FIG. 1, and FIG. 3 is a cap tightening control circuit diagram for carrying out the present invention, FIG. 4 is a flowchart of cap tightening control for carrying out the present invention, FIG. 5 shows an example of a control pattern for carrying out the present invention, and FIG. 6 is another example of a control pattern for carrying out the present invention. Show. FIG. 7 shows a control circuit diagram of a conventional screw capper. 57 …… Torque variable motor 91 …… Screw cap 92 …… Screw cap head 93 …… Spindle assembly 109 …… Controller 111 …… First motor output torque setter 112 …… Second motor output torque setter 121… … 1st motor rotation speed setting device 122 …… 2nd motor rotation speed setting device 131 …… Reference torque setting device 104 …… Comparison circuit 105 …… Timer circuit 102, 103 …… Voltage switching device

Claims (1)

[Claims] 1. A capping device for mounting a torque variable motor on each head to tighten a screw cap,
Each setting device that sets the rotation speed, output torque, and reference torque of the torque variable motor, and a comparison circuit that adds and subtracts the output signal of the reference torque setting device and the motor output torque value are provided, and output from the comparison circuit. The torque signal is passed through the timer, and the rotation speed signal is led through the switch without passing through the timer, and the rotation speed and torque of the screw cap head tightened by the torque variable motor are controlled to control the screw type cap. Tightening method.