JP2004099146A - Speed control device for sealing mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To controlling setting time for clamping a tube film with a pair of sealing bars. <P>SOLUTION: A crank mechanism 36 to reciprocate a seal bar frame 19 along a rail 35 is provided with an arm 40 swingable around a support shaft 39 at one end and a circular crank plate 43 rotated by power of a central shaft 42. A thin slider 45 to engage with a slide guide 44 formed on a lower surface of the arm 40 is fixed to a crank shaft 46 of a deviation part of the crank plate 43. The thin slider 45 is formed to exceed amount of θ1,θ2, respectively in 180°arc of semi-circle area formed around a central shaft 42 which is a range of 55-56 points, relative to a top dead point 53 and lower dead point 54 of the arm 40. A servomotor to drive the central shaft 42 controls speed to be equalized at 55-56 points of 180°arc of semi-circle area and a frame 19 is advanced and retreated along a rail 35 with high speed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is a seal mechanism for operating a pair of heating seal bars, which are arranged with a tube film moving in a longitudinal direction therebetween, in a block motion in the same direction as the film, wherein a seal bar moving process speed in the same direction as the film. To a control device for maximizing the constant.
[0002]
[Problems to be solved by the invention]
While the belt-shaped film is transported while being rolled into a tube and formed into a tube, the objects to be packaged are carried into the tube film at equal intervals, and the tube film is crossed by a pair of seal bars so as to isolate each object to be packaged. In a bag making, filling and packaging machine for sealing, since it is necessary to prolong the heating time for a film having a low degree of melting, both seal bars holding the tube film are moved in the same direction as the film for a certain period of time and the film is moved. You must retreat away from orbit. In short, both seal bars are operated in block motion.
[0003]
Conventionally, Japanese Patent Application Laid-Open No. Hei 7-291234 discloses that a seal bar support frame is reciprocated along a tube film transfer trajectory by a revolving motion of a crankshaft, and a pair of seal bars are moved toward and away from each other in the frame. This discloses that both seal bars perform a block motion operation. However, the crankshaft can use only one-half of its orbit as a forward region of the seal bar support frame, and the top dead center and the bottom dead center of the orbit of the revolving orbit have extreme speeds with a stop point interposed therebetween. However, there is a problem that the movement of the seal bar can be stabilized only at about 120 degrees due to the presence of an area that is reduced.
[0004]
[Solution]
According to the present invention, a pair of seal bars for closing the tube film between the front and rear packaged objects and simultaneously performing vacuum suction from the cut portion formed in the closed portion into the film are formed by a half of the crankshaft orbit. For the purpose of moving the area at a constant speed, the rocking motion of the arm with the support shaft at one end as the fulcrum is transmitted to the seal bar support frame via the connecting rod, so that it is activated along the tube film transfer path. By the combined movement of the reciprocating movement of the frame and the pair of seal bars arranged on the frame, the approach and separation movements of the two seal bars separated from each other by the tube frame, the two seal bars are operated in a block motion, and the two seal bars are operated. While the tube film was being pressed, the air in the film was removed by suction from the cuts made in the film in the pressing area of both seal bars. A device for heating and sealing the cut, wherein a slider supported on a crankshaft is slidably engaged with a guide formed along the arm, and the arm is swung by the crankshaft revolved by a servomotor. And an arithmetic signal is sent to the servomotor so that the arm swinging speed is constant in a 180 ° crankshaft revolving angle region inside the deceleration range on both sides of the arm swinging range. And a controller.
[0005]
The arm that swings due to the circular revolving motion of the crankshaft has the support shaft at one end as a fulcrum and the open end swings in an arc, so that the closer the support shaft is to the center of the revolution circle of the crankshaft, It is possible to advance the seal bar support frame in the area of the orbital circle of the crankshaft of 1/2 or more, that is, in the area of the orbital angle of 180 degrees or more, and to retreat the seal bar support frame in the remaining area of 180 degrees or less at high speed. It is. In short, the shorter the distance from the center point of the revolving circle to the center of the one end support shaft of the arm, the shorter the retreat area of the seal bar support frame becomes, and the advance area of the support frame can be adjusted so as to expand accordingly. It is. Therefore, by storing in a memory at least calculation data for stabilizing the swinging angular velocity of the arm in the above-mentioned revolution angle region of 180 degrees, the controller outputs an operation signal every time the crankshaft reaches the above-mentioned revolution angle region of 180 degrees. Thus, the rotation speed of the servomotor is controlled so that the swing angular velocity of the arm is constant. As a result, it is possible to perform the sealing for a relatively long time, in which the vacuum suction in the tube film by the two seal bars and the heat sealing of the cut are performed in stages, without lowering the efficiency.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2 is an overall view of the bag making and filling machine. A belt-like film 12 pulled out by a roll 11 rotating integrally with a motor 10 is rolled into a tube 14 by passing through a cylindrical former 13. On the other hand, the chain conveyor 16 rotated by the carry-in motor 15. Each packaged object 17 is carried into the tube film 14 at equal intervals. The frame 19, which supports the opposite ends of the first conveyor 18 and the second conveyor 18 respectively, includes a pair of upper and lower seal bars 21 and 22 for welding a film.
[0007]
FIG. 3 is a front view of the seal bar support frame 19, in which a motor 23 mounted on the same frame 19 and an operation shaft 25 supported between a pair of slide blocks 24 on both lower sides of the frame are paired with a pair of gears 26. And a bell crank 27 is fixed to both ends of the operation shaft 25, and a pair of upper and lower members 29 and 30 are supported on a guide rod 28 erected from the two slide blocks 24. The seal bars 21 and 22 are fixed to the bridge members 29 and 30, respectively, and the operation shaft 25 is swung in the forward and reverse directions by the power of the motor 23, thereby being connected to the bell crank 27 at both ends via the links 32 and 33. The upper and lower seal bars 21 and 22 approach and separate from each other to heat seal the tube film 14 at regular intervals.
[0008]
FIG. 1 is a plan view of the frame 19 supported on a pair of rails 35 and a crank mechanism 36 for reciprocating the frame 19 along the rails 35. As shown in FIG. 4, the details of the crank mechanism 36 are a swingable arm 40 which supports a support shaft 39 at one end on a bearing 38 fixed to the machine base 37, and a second arm 40 fixed to the machine base 37. The bearing 41 includes a circular crank plate 43 that supports the center shaft 42. Further, a grooved slider 45 engaged with a slide guide 44 formed along the longitudinal direction of the lower surface of the arm 40 is fixed to a crankshaft 46 rotatably supported on an eccentric portion of the crank plate 43, while a servo A shaft 49 connected to the motor 47 via a belt 48 is supported by a third bearing 50, and a pinion 51 fixed to an upper end of the shaft 50 is engaged with a parallel tooth 52 formed on a peripheral edge of the crank plate 43. Configure.
[0009]
In FIG. 5, when the crank plate 43 is rotated by the rotational power of the pinion 51 connected to the servomotor 47, the crankshaft 46 revolves around the central axis 42 along the trajectory 53 indicated by the arrow. Is displaced along the slide guide 44 of the arm 40, and as a result, the arm 40 swings around the support shaft 39 at one end. In this case, the top dead center 53 and the bottom dead center 54 of the arm 40 swinging about the support shaft 39 in FIG. 1 are defined as a 180-degree region connecting the central axis 42, that is, the range of the points 55 to 56 is θ1, The connecting rod 54 is formed so as to extend by θ2, and the connecting rod 54 moves the frame 19 forward along the rail 35 and retreats at high speed in the region of the both dead points 53 and 54.
[0010]
FIG. 7 is an analysis diagram obtained by dividing the swing angle of the arm of 310 mm in length with the support shaft 39 as a fulcrum when the crankshaft 46 revolves on a circular orbit 58 with a radius of 80.36 mm by 10 degrees. , An arm swing angle value 59 per 10 degree division and a millimeter value 60 for each angle value are displayed. When the numerical value 59 of the arm swing angle which is divided into 18 between points 55 and 56 corresponding to the 180-degree radius in the figure is enlarged, the range of the swing angles (1) to (9) of the arm in FIG. And the lengths of these angle values correspond to the corresponding dimensions in the right column. Therefore, the average value of the nine values in the right column is calculated to be 11.77 mm. Therefore, the servomotor 47 is moved so that the arm moves by 11.77 mm for each of the swing angles (1) to (9). Control. Note that the total value of 7.77 mm at the bottom of the table is the value of each of θ1 and θ2 in FIG. 1, and the pair of seal bars 21 and 22 move in the range of the linear track 70 at a uniform speed in FIG. The block motion operation is performed by looping back in the regions 71 and 72, and the regions 71 and 72 correspond to θ1 and θ2 in FIG.
[0011]
The reference cycle transmitter 74 in FIG. 10 is the same as the pulse transmitter 74 attached to the carry-in motor 15 in FIG. 2, and the pulse transmitter 74 has the same pitch as the carry-in pitch of the packaged object 17 to the tube film 14. A signal is transmitted to the controller to control the servo motor 47 in the same cycle. The data shown in FIG. 8 and a formula for calculating the average value are input to the memory 76 in FIG. 10, and the position angle from the rotation feedback signal 78 from the servomotor 47 in FIG. In addition to the calculation, the output speed of the servomotor 47 is controlled based on the corresponding data stored in the memory 76.
[0012]
When the length of the articles 17 to be loaded into the tube film by the carry-in conveyor 16 in FIG. 2 is changed to a shorter length, the speed of the film motor 10 is reduced to adjust the distance between the articles 17 to be kept constant. In this case, however, in FIG. 4, the screw rod 81 is rotated by the micromotor 80, and the pin 82 supporting the end of the connecting rod 57 is displaced along the guide 83, so that the reciprocating movement amount of the seal bar support frame 19 in FIG. adjust.
[0013]
FIG. 11 shows a seal mechanism installed on a seal bar support frame. The mechanism sandwiches the tube film 14 between upper and lower blocks 85 and 86 and applies vacuum pressure to first vacuum lines 86 and 87 to form the tube. The air in the tube film 14, which is sucked so as to form a gap between the films 14 and is opened by the cutting action of the cutting blade 88, is removed from the second vacuum line 87 as indicated by a dotted arrow, and then the upper and lower sides are removed. The structure is such that the bag mouth is heated and sealed by the relative approach of the two seal bars 21 and 22. As described above, the mechanism performs the heat sealing step for the tube film and the vacuum suction step in two stages, and since the traveling time on the linear track is relatively long, the arm 40 shown in FIG. This is to make the best use of the constant speed movement.
[Brief description of the drawings]
FIG. 1 is a plan view of a crank mechanism and a seal bar support frame. FIG. 2 is a side view of a bag making and filling machine. FIG. 3 is a front view of a seal bar support frame. FIG. 4 is a side view of a crank mechanism. FIG. 6 is a plan view of the previous figure. FIG. 6 is a cross-sectional view of a joint portion between the crankshaft and the arm. FIG. 7 is an explanatory view of a numerical value of the swing angle of the arm. FIG. 9: Illustration of the block motion trajectory of the seal bar [FIG. 10] Description of the control device [FIG. 11] Cross-sectional view of the seal bar [Description of reference numerals]
14: Tube film 17: Packaged object 19: Seal bar support frames 21, 22-Bar 40: Arm 45 ... Slider 46 ... Crank shaft 47 ... Servo motor 57 ... Conduit 74 ... Reference cycle transmitter 75 ... Controller 76 ... Memory 78 feedback signal 79 arithmetic unit 80 micromotor 81 screw rod 82 pin 83 slide guide 88 cutter for forming cuts

Claims (3)

By transmitting the swinging motion of the arm with the support shaft at one end as a fulcrum to the seal bar support frame via the connecting rod, the reciprocating motion of the frame activated along the transfer trajectory of the tube film, By the combined movement of the pair of seal bars disposed, approaching and separating the tube frame from each other, the two seal bars are operated in block motion,
An apparatus for heat-sealing the cuts after suctioning and removing air in the film from the cuts to be applied to the film in the pressurizing region of both seal bars while both seal bars are pressing the tube film,
A mechanism for slidably engaging a slider supported on a crankshaft with a guide formed along the arm, and swinging the arm by the crankshaft revolving by a servomotor,
A controller that sends a calculation signal to the servomotor so that both sides of the arm swing range are deceleration ranges, and the swing speed of the arm is constant in a region of a rotation angle of the crankshaft of 180 degrees inside the deceleration range. Equipment to have. The controller matches the rotation cycle of the servo motor with the cycle signal from the reference cycle transmitter, and calculates the position angle from the rotation feedback signal from the servo motor by the arithmetic unit and stores it in the memory. The apparatus according to claim 1, wherein the output speed of the servomotor is controlled based on the corresponding data. A pin is engaged with a threaded rod disposed along the arm, while an end of a conload connected to a seal bar support frame is engaged with the pin, and the pin is rotated by rotation of the threaded rod by a micromotor, and the threaded rod is rotated. 2. The apparatus according to claim 1, wherein the apparatus is adapted to be displaced along.

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