JP3727530B2 - Shutter device for thermoforming machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shutter device for a thermoforming machine.
[0002]
[Prior art]
Conventionally, the heat of a resin sheet for forming a continuous resin sheet to form a molded product made of resin such as a container for storing food, beverages, electrical parts, daily necessities, pharmaceuticals, etc., and a lid (lid) of the container In the molding line, a thermoforming machine that has an upper mold and a lower mold and molds a heated resin sheet by clamping is used.
[0003]
Here, the thermoforming machine is an apparatus for forming a molded product on the continuous resin sheet by a thermoforming method, and the resin sheet is intermittently conveyed by a conveying apparatus for each length required for forming one shot. And fed into the thermoforming machine. A trimming device is disposed downstream of the thermoforming machine in the resin sheet conveying direction. In the trimming device, the molded product is cut from the resin sheet, separated and integrated, and then packaged, boxed, etc. It is sent to the subsequent process.
[0004]
On the other hand, a heating device is disposed on the upstream side of the thermoforming machine in the resin sheet conveying direction, in which the resin sheet is heated to a temperature suitable for molding and sent to the thermoforming machine. . And the said heating apparatus has a radiant heater normally arrange | positioned at the upper and lower sides of the conveyance path of the said resin sheet, and heats the said resin sheet with the radiant heat from this radiant heater. Yes.
[0005]
By the way, in thermoforming, the positioning of the resin sheet at the time of mold clamping and molding is an extremely important molding factor. Therefore, the resin sheet sent to the thermoforming machine is gripping means when mold clamping and molding. Need to be held and fixed by.
[0006]
In addition, since the heat inside the heating device can easily escape from the outlet portion of the heating device, that is, the portion on the thermoforming machine side, it is necessary to provide a member for preventing the heat from being released at the outlet portion of the heating device. There is.
[0007]
In order to solve such a problem, in a conventional thermoforming machine, it is opened and closed at a position between the heating apparatus, that is, at an inlet of the thermoforming machine that is a position facing the outlet of the heating apparatus. A type of shutter is arranged. In this case, the shutter is opened when the resin sheet is conveyed, and is closed when the resin sheet is stopped so as to sandwich the resin sheet from above and below. Thus, not only does the heat not escape from the heating device, but also when the mold is clamped and molded, the resin sheet is gripped and positioned from above and below by the shutter, so that the molded product is accurately Molded on top.
[0008]
As described above, by disposing an openable shutter at the inlet of the thermoforming machine, heat does not escape from the heating device, so that thermal efficiency is improved and the resin sheet is gripped and positioned by the shutter from above and below. Therefore, since the molded product is accurately molded on the resin sheet, the resin sheet is favorably thermoformed in the thermoforming machine, and a high-quality molded product can be molded.
[0009]
[Problems to be solved by the invention]
However, in the conventional shutter device for a thermoforming machine, since the upper and lower shutters are driven by an air cylinder to move up and down, the operation is not reproducible, and in particular the timing at which the thermoforming machine clamps the mold. And the timing at which the upper and lower shutters close may be misaligned.
[0010]
In this case, the resin sheet is not gripped from above and below by the shutter, that is, the mold clamping is started without being positioned. Therefore, the resin sheet is drawn into the mold side with mold clamping, causing a positional shift, and molding. The product will not be accurately molded on the resin sheet.
[0011]
In addition, since the air cylinder generally has a low operating speed, it is difficult to cope with the recent increase in the speed of the resin sheet thermoforming line. In particular, the lower shutter has a large amount of movement, and when closing the shutter, a heavy load such as the lower shutter is lifted, so that a high load is applied to the air cylinder that drives the lower shutter. . Therefore, it has been extremely difficult to increase the speed of the air cylinder that drives the lower shutter.
[0012]
Furthermore, even when the speed of the air cylinder is increased, it is difficult to finely control the operating speed of the air cylinder, so that the control of the moving speed immediately before the shutter closes, that is, just before the stop becomes unstable. In particular, the lower shutter is designed to lift the resin sheet that hangs down from the middle of movement, so if the moving speed of the shutter just before the stop is too fast, the resin sheet will overshoot upward due to inertia. It becomes impossible to position.
[0013]
In order to improve the reproducibility of the operation, it may be possible to use an AC servo device using a ball screw instead of the air cylinder. However, the AC servo device using such a ball screw can increase the operation speed. Since it is difficult and the size becomes large, it is unsuitable for use in a shutter device for a thermoforming machine.
[0014]
The present invention solves the problems of the conventional shutter device for a thermoforming machine, and moves the lower shutter up and down using a link mechanism driven by a servo motor, so that the reproducibility of the operation is good. Another object of the present invention is to provide a shutter device for a thermoforming machine that has a high operating speed and that can be easily controlled.
[0015]
[Means for Solving the Problems]
  For this purpose, in the shutter device for a thermoforming machine of the present invention, the resin sheet inlet in the thermoforming machine is provided with an upper mold and a lower mold and molds a heated resin sheet by clamping the upper mold and the lower mold. An upper shutter disposed in a portion of the resin sheet above the conveyance path of the resin sheet so as to be movable up and down, and disposed at a position facing the upper shutter below the conveyance path of the resin sheet. A lower shutter that cooperates to grip the resin sheet, a servo motor that reciprocates within a predetermined angle range, and a reciprocating rotational motion of the servo motor that converts the reciprocating motion of the servo motor into a linear reciprocating motion in the vertical direction. Link mechanism to transmitThe link mechanism includes a crank arm fixed to the rotation shaft of the servo motor, a connecting rod rotatably connected to the end of the crank arm, and the angular velocity of the servo motor is constant. The moving speed of the lower shutter is low when the lower shutter is near the bottom dead center and near the top dead center, and when the lower shutter is between the bottom dead center and the top dead center Configured to be high.
[0016]
Another shutter device for a thermoforming machine of the present invention further includes a cylinder device for reciprocating the upper shutter.
[0018]
  In still another thermoforming machine shutter device of the present invention, the link mechanism is further provided.BeforeLower drive rod that can move in the vertical direction to transmit linear reciprocating motion to the lower shutterThe connecting rod is rotatably connected to the lower end of the lower drive rod.
[0019]
In still another thermoforming machine shutter device according to the present invention, the crank arm has a counterweight fixed to an end opposite to the end to which the connecting rod is connected.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0022]
1 is a view taken along the line AA of FIG. 3, FIG. 2 is an overall side view of the thermoforming machine and the heating device for the thermoforming machine in the first embodiment of the invention, and FIG. 3 is the first embodiment of the invention. FIG. 4 is an enlarged cross-sectional view taken along the line B-B of FIG. 1 and FIG. 5 is an enlarged view of part C of FIG. 4. FIG. 6 and FIG. 6 are enlarged views of a portion D in FIG.
[0023]
In the figure, reference numeral 10 denotes a heating device for a thermoforming machine, and on a continuous resin sheet 14, food such as cup noodles, sashimi, jelly, beverages such as fruit juice, carbonated water, electrical parts, daily necessities, pharmaceuticals, etc. In a thermoforming line of a resin sheet 14 for molding a container to be accommodated and a resin molded product such as a lid of the container, the thermoforming machine 30 is disposed upstream of the thermoforming machine 30 in the conveying direction of the resin sheet 14. The resin sheet 14 fed into the machine 30 is heated to a temperature suitable for molding.
[0024]
And the said thermoforming machine 30 shape | molds the said molded article on the said resin sheet 14 with thermoforming methods, such as vacuum forming, pressure forming, drawing forming, press forming, matched mold forming, for example.
[0025]
The heating device 10 for the thermoforming machine may be disposed away from the thermoforming machine 30, but in this case, the temperature of the resin sheet 14 sent out from the heating device 10 for the thermoforming machine is lowered. Therefore, from the viewpoint of thermal efficiency, it is desirable that the heating device for a thermoforming machine 10 and the thermoforming machine 30 are disposed close to each other.
[0026]
Further, the resin sheet 14 is gripped at both ends by a conveying device 13 having a chain, belt, etc. having pins and clamps, and leftward in FIG. 3 by the length required for molding one shot by a driving device (not shown). , Being intermittently conveyed, fed out from the raw roll 15 and fed into the thermoforming machine 30. A trimming device (not shown) is disposed on the downstream side in the conveying direction of the resin sheet 14 of the thermoforming machine 30. In the trimming device, the molded product is cut, separated, and accumulated from the resin sheet 14. , And sent to post-processing such as packaging and boxing.
[0027]
The resin sheet 14 in the present embodiment may be any material, for example, PVC (polyvinyl chloride), PS (polystyrene), expanded polystyrene, PP (polypropylene), PE (polyethylene), PET ( Polyethylene terephthalate), PC (polycarbonate), ABS resin, methacrylic resin, biodegradable resin and the like are used. In consideration of water resistance, gas barrier properties, etc., a sheet in which a plurality of types of resins are laminated can also be used.
[0028]
Reference numeral 11 denotes an upper heater device disposed above the conveying path of the resin sheet 14 in the heating device 10 for the thermoforming machine, and 12 denotes the resin sheet 14 in the heating device 10 for the thermoforming machine. The upper heater device 11 and the lower heater device 12 are respectively moved upward and downward by a lift driving device (not shown).
[0029]
Here, the upper heater device 11 is a single sheet-like heater as a whole by disposing a plurality of block-shaped radiation heaters comprising a sheathed heater, a porcelain heater, an infrared bulb heater, etc. on the same surface. The resin sheet 14 is heated from above by radiation. In addition, the magnitude | size of the said block-shaped radiation heater does not necessarily need to be the same magnitude | size.
[0030]
Note that which one of the sheathed heater, the porcelain heater, the infrared bulb heater and the like is selected is a matter made in consideration of the heating temperature, the performance of the heater, the material of the resin sheet 14, and the like. For example, when the resin sheet 14 is PP, PE, PS, or ABS resin, a sheathed heater is selected. When the resin sheet 14 is a foamed polystyrene or a thick sheet, a porcelain heater is preferably selected. Further, the temperature of the upper heater device 11 is preferably about 500 to 700 [° C.] when the block radiation heater is a sheathed heater, and about 300 to 500 [° C.] when it is made of a porcelain heater. .
[0031]
On the other hand, the lower heater device 12 is for heating the resin sheet 14 from below by radiation, and has the same structure as the upper heater device 11, and with respect to the transport path of the resin sheet 14, The upper heater device 11 is arranged symmetrically.
[0032]
In addition, the dimension of the conveyance direction of the said upper heater apparatus 11 and the lower heater apparatus 12 is a little longer than the double length of the said resin sheet 14 required for shaping | molding of 1 shot. Therefore, the resin sheet 14 is heated in the thermoforming machine heating apparatus 10 only for a time during which the thermoforming machine 30 performs two-shot molding.
[0033]
In more detail, in the first zone on the resin sheet inlet side (right side in FIG. 3) in the heating apparatus 10 for the thermoforming machine, the thermoforming machine 30 is stopped while performing one shot molding. The portion of the resin sheet 14 is intermittently fed by the conveying device 13 after the thermoforming machine 30 is molded by one shot, and the resin sheet outlet side in the heating device 10 for the thermoforming machine (in FIG. 1) Move to the second zone on the left and stop. Subsequently, after the thermoforming machine 30 is stopped while performing one-shot molding, the thermoforming machine 30 is intermittently fed by the transfer device 13 and fed into the thermoforming machine 30.
[0034]
Further, an upper shielding plate 16 and a lower shielding plate 17 are disposed in the vicinity of the resin sheet inlet in the heating apparatus 10 for the thermoforming machine, with the conveyance path of the resin sheet 14 interposed therebetween. Here, the upper shielding plate 16 and the lower shielding plate 17 are for shielding radiant heat from the upper heater device 11 and the lower heater device 12, and are arranged to be movable in the transport direction.
[0035]
Here, when the portion of the resin sheet 14 on the right side in FIG. 3 from the starting point on the resin sheet inlet side of the first zone is heated, the portion is further further, in the first zone and the second zone, in the first zone and the second zone. Since the thermoforming machine 30 is heated for two shots, the temperature rises too much. In order to prevent this, the block radiation heater on the right side of the starting point on the resin sheet inlet side of the first zone stops heating, but the block radiation corresponding to the first zone is stopped. Since the radiant heat from the heater is also applied to the portion of the resin sheet 14 on the right side of the starting point on the resin sheet inlet side of the first zone, the portion is heated.
[0036]
In this case, by arranging the upper shielding plate 16 and the lower shielding plate 17, the portion of the resin sheet 14 on the right side of the starting point on the resin sheet entrance side of the first zone corresponds to the first zone. Therefore, the resin sheet 14 is heated by the radiant heat from the upper heater device 11 and the lower heater device 12 before being carried into the first zone, so that the temperature is increased. It will not rise too much.
[0037]
The thermoforming machine 30 includes an upper table drive actuator and a lower table drive actuator (not shown) fixed to a frame 31, and an upper table 32 and a lower table 34 attached to the upper table drive actuator and the lower table drive actuator, respectively. Each of the upper table 32 and the lower table 34 has an upper mold 33 and a lower mold 35 that are detachably attached.
[0038]
Here, the upper mold 33 and the lower mold 35 are usually one female type and the other male type, but when the thermoforming machine 30 is a vacuum forming machine, for example, a plug is used instead of the male type. Can also be used. In addition, when the molded product is a small container such as a container for storing food, beverages, electric parts, daily necessities, medicines, etc., or a lid of the container, the upper mold 33 and the lower mold 35 are usually a plurality of each. A molding die is provided, and a plurality of molded products are molded on the resin sheet 14 in one molding operation, that is, in one shot. For example, when the molded product is a small container, the upper mold 33 and the lower mold 35 are ten in the width direction (left-right direction in FIG. 1) of the resin sheet 14, and the resin sheet conveyance direction (left-right direction in FIG. 3). ) In 5 rows, a total of 10 × 5 = 50 molds.
[0039]
In addition, smaller upper molds and lower molds can be used in place of the upper mold 33 and the lower mold 35 according to the production plan of the resin sheet molding line, the width of the resin sheet 14, and the like.
[0040]
An open / close shutter device is disposed between the thermoforming machine 30 and the thermoforming machine heating device 10. In this case, the shutter device includes an upper shutter device 40 and a lower shutter device 50 and is attached to the frame 31 at the entrance portion of the resin sheet 14 in the thermoforming machine 30.
[0041]
Here, as shown in FIGS. 1 and 4, the upper shutter 40 includes an upper support member 41 that is movable up and down, an upper sheet grip plate 42 that is fixed to a lower portion of the upper support member 41, and the upper shutter 40. The upper heat seal plate 43 is fixed to the upper portion of the support member 41.
[0042]
The upper support member 41 extends in the vertical direction, and upper and lower ends thereof are fitted to the left and right guide rods 46 fixed to the frame 31 so as to be slidable. A lower end portion of the upper drive rod 44 extending in the vertical direction is fixed to the central portion of the upper support member 41.
[0043]
Further, the upper end of the upper drive rod 44 is connected to a piston of a drive cylinder device 45 as shown in FIG. The drive cylinder device 45 is an air cylinder, but may be a hydraulic cylinder.
[0044]
Accordingly, the upper support member 41, the upper sheet grip plate 42, and the upper heat seal plate 43 are integrally moved up and down when the drive cylinder device 45 is driven.
[0045]
On the other hand, as shown in FIGS. 1 and 4, the lower shutter 50 includes a lower support member 51 that is movable up and down, a lower sheet grip plate 52 that is fixed to the upper portion of the lower support member 51, and The lower heat sealing plate 53 is fixed to the lower portion of the lower support member 51.
[0046]
The lower support member 51 extends in the vertical direction, and upper and lower ends thereof are slidably fitted to the left and right guide rods 46 fixed to the frame 31. Further, an upper end portion of a lower drive rod 54 extending in the vertical direction is fixed to a central portion of the lower support member 51.
[0047]
Further, as shown in FIG. 6, one end of a connecting rod 56 is rotatably attached to the lower end of the lower drive rod 54, and the other end of the connecting rod 56 is connected to an AC servo. It is rotatably attached to the end of a crank arm 57 fixed to the shaft of a servo motor 55 such as a motor. The servo motor 55 is fixed to the lower part of the frame 31. Thus, the lower drive rod 54, the connecting rod 56 and the crank arm 57 constitute a link mechanism.
[0048]
Accordingly, the lower support member 51, the lower sheet grip plate 52, and the lower heat seal plate 53 are integrally moved up and down by the link mechanism when the servo motor 55 rotates.
[0049]
The lower sheet grip plate 52 and the lower heat seal plate 53 are preferably made of aluminum from the viewpoint of weight reduction.
[0050]
The shutter device opens when the resin sheet 14 is conveyed, closes when the resin sheet 14 is stopped, and moves the resin sheet 14 up and down by the upper sheet holding plate 42 and the lower sheet holding plate 52. It is supposed to be sandwiched between. That is, the upper shutter 40 and the lower shutter 50 cooperate to grip the resin sheet 14. Thereby, not only does the heat not escape from the heating device 10 for the thermoforming machine, but the resin sheet 14 is positioned, so that the molded product is accurately formed on the resin sheet 14.
[0051]
The transport device 13 is disposed on both sides of the transport path of the resin sheet 14 so as to be movable in the width direction of the resin sheet 14. That is, the left and right transport devices 13 have parallel portions and inclined portions, and can move so that the distance between them can be changed according to the width dimension of the resin sheet 14. Yes.
[0052]
The thermoforming machine 30 has a control device (not shown). The control device includes arithmetic means such as CPU and MPU, storage means such as semiconductor memory and hard disk, input means such as mouse, keyboard and touch panel, display means such as CRT and liquid crystal display, I / O (input / output interface), etc. Have The control device controls the operations of the upper table drive actuator, the lower table drive actuator, the drive cylinder device 45, the servo motor 55, the transport device 13, and the like based on an operator command or a pre-input program.
[0053]
Further, the control device comprehensively controls the operation of all or part of the thermoforming machine 30. Note that the control device is not independent, and is integrated with other control devices as part of a control device that controls devices such as the thermoforming machine heating device 10 and the trimming device in a resin sheet molding line. Can also be used.
[0054]
Moreover, it is desirable that the heating device 10 for a thermoforming machine has a wall member (not shown) that covers the periphery for heat insulation. The wall member has a heat insulating material, and is attached so as to cover the upper, lower, left, and right front and back surfaces of the heating apparatus 10 for a thermoforming machine. However, an opening is formed in a portion through which the resin sheet 14 passes or a portion through which a part of the apparatus passes or protrudes. In this case, in order to improve thermal efficiency, it is desirable to reduce the area of the opening as much as possible and to attach an open / close shutter.
[0055]
In order to improve the thermal efficiency of the thermoforming machine 30, it is desirable to have a wall member. In this case, a wall member integral with the wall member of the heating apparatus 10 for a thermoforming machine may be attached.
[0056]
Next, the operation of the shutter device for a thermoforming machine having the above configuration will be described.
[0057]
First, in the heating apparatus 10 for a thermoforming machine, the resin sheet 14 is unwound from the raw roll 15 and is intermittently conveyed from the right side to the left side in FIG. The resin sheet 14 is stopped for a predetermined time in the heating device 10 for the thermoforming machine, and during that time, the temperature range optimum for molding by the radiant heat from the upper heater device 11 and the lower heater device 12, that is, the molding temperature. Until heated.
[0058]
At this time, the drive cylinder device 45 is driven, the upper shutter 40 including the upper support member 41, the upper sheet grip plate 42, and the upper heat seal plate 43 is moved downward, and the servo motor 55 is driven, The lower shutter 50 including the lower support member 51, the lower sheet grip plate 52, and the lower heat seal plate 53 is moved upward. Thus, the upper sheet grip plate 42 of the upper shutter 40 and the lower sheet grip plate 52 of the lower shutter 50 grip the resin sheet 14 from above and below.
[0059]
The molding temperature varies depending on molding conditions, the type and thickness of the resin sheet 14, and generally in thermoforming, when the resin sheet 14 is PVC, 120 to 140 [° C.], PS 110 to 150 [° C.] in the case of PP, 170 to 220 [° C.] in the case of PP, 140 to 190 [° C.] in the case of PE, 130 to 150 [° C.] in the case of ABS resin, and 135 to 135 in the case of PET. It is about 155 [° C.].
[0060]
Here, the heating temperature of the resin sheet 14 is controlled by adjusting the outputs of the upper heater device 11 and the lower heater device 12 to control the amount of radiant heat. By moving the heater device 11 and the lower heater device 12 upward and downward and adjusting the distance between the resin sheet 14 and the upper heater device 11 and the lower heater device 12, respectively, a predetermined molding temperature can be obtained. it can.
[0061]
Further, when the portion of the resin sheet 14 on the right side in FIG. 3 from the starting point on the resin sheet inlet side of the first zone is heated, the portion is further further in the first zone and the second zone. Since the thermoforming machine 30 is heated for two shots, the temperature rises too much. In order to prevent this, the block on the right side of the starting point on the resin sheet inlet side of the first zone. It is desirable to stop the radiant heater.
[0062]
Furthermore, since the radiant heat from the block-shaped radiant heater corresponding to the first zone is also given to the portion of the resin sheet 14 on the right side of the starting point on the resin sheet inlet side of the first zone, the portion is heated. Therefore, the position of the upper shielding plate 16 and the lower shielding plate 17 is adjusted, and the portion of the resin sheet 14 on the right side of the starting point on the resin sheet inlet side of the first zone becomes the first zone. It is desirable to be shielded from the radiant heat of the corresponding block radiant heater.
[0063]
Thereby, before carrying in to the said 1st zone, the said resin sheet 14 is heated by the radiant heat from the said upper heater apparatus 11 and the lower heater apparatus 12, and temperature does not rise too much.
[0064]
When the upper mold 33 and the lower mold 35 of the thermoforming apparatus 30 are changed to those having different sizes, and the feed amount of one shot of the resin sheet 14 is changed, the first zone and the second zone The length of will change. In such a case, since the range on the right side of the starting point on the resin sheet inlet side of the first zone is also changed, the range of the block-shaped radiation heater to be stopped is also changed. Further, the positions of the upper shielding plate 16 and the lower shielding plate 17 are also adjusted.
[0065]
Next, the resin sheet 14 heated to the molding temperature is conveyed and fed into the thermoforming machine 30.
[0066]
At this time, the drive cylinder device 45 is driven to move the upper shutter 40 upward, and the servo motor 55 is driven to move the lower shutter 50 downward. As a result, the upper sheet grip plate 42 of the upper shutter 40 and the lower sheet grip plate 52 of the lower shutter 50 open the resin sheet 14. Thereby, the resin sheet 14 is smoothly conveyed.
[0067]
When the resin sheet 14 stops at a predetermined position, the drive cylinder device 45 is driven again, the upper shutter 40 is moved downward, and the servo motor 55 is driven to move the lower side. The shutter 50 is moved upward. Thus, the upper sheet grip plate 42 of the upper shutter 40 and the lower sheet grip plate 52 of the lower shutter 50 grip the resin sheet 14 from above and below.
[0068]
On the other hand, when the resin sheet 14 stops at a predetermined position, an upper table drive actuator and a lower table drive actuator (not shown) are operated, and the upper mold 33 and the lower mold 35 move downward and upward, thereby clamping the resin sheet 14. To form a molded product. Here, when the molded product is a small container, for example, 50 molded products are molded in one shot. Thereafter, the upper mold 33 and the lower mold 35 are moved upward and downward, that is, in directions away from each other, to open the mold.
[0069]
During this time, in the heating apparatus 10 for a thermoforming machine, the resin sheet 14 having a length corresponding to one shot is stopped and heated to a molding temperature.
[0070]
Next, the drive cylinder device 45 is driven again to move the upper shutter 40 upward, and the servo motor 55 is driven to move the lower shutter 50 downward. As a result, the upper sheet grip plate 42 of the upper shutter 40 and the lower sheet grip plate 52 of the lower shutter 50 open the resin sheet 14. Then, the resin sheet 14 is conveyed again, the molded product is conveyed downstream in the resin sheet conveying direction and sent out from the thermoforming machine 30, and the resin sheet 14 having a length for the next one shot is transferred to the thermoforming machine. 30.
[0071]
By repeating the above operation, a large number of molded products are continuously molded in the resin sheet molding line.
[0072]
Here, the operation of the lower shutter 50 will be described in detail.
[0073]
FIG. 7 is a diagram illustrating a state where the servo motor 55 rotates and the lower shutter 50 is moved up and down by the link mechanism.
[0074]
First, when the resin sheet 14 is conveyed, the lower support member 51 of the lower shutter 50 is moved downward, and the link mechanism including the lower drive rod 54, the connecting rod 56, and the crank arm 57 is shown in FIG. The state is as shown in FIG.
[0075]
When the resin sheet 14 stops at a predetermined position, the servo motor 55 is driven and the lower shutter 50 is moved upward. In this case, the servo motor 55 rotates clockwise in FIG. Then, the lower drive rod 54 is moved upward by the link mechanism, and the lower shutter 50 is raised. In order to prevent the lower drive rod 54 from swinging in the lateral direction, a guide member may be provided along the side surface of the lower drive rod 54.
[0076]
When the lower shutter 50 approaches the top dead center, the link mechanism is in a state as shown in FIG.
[0077]
When the lower shutter 50 is moved downward, the servo motor 55 is rotated counterclockwise. That is, the servo motor 55 does not rotate in one direction but swings, that is, reciprocates within a predetermined angle range.
[0078]
Here, due to the structure of the link mechanism, when the angular speed of the servo motor 55 is constant, the moving speed of the lower drive rod 54 and the lower shutter 50 is high when the crank arm 57 is in a state of being almost horizontal. It can be seen that the moving speed of the lower drive rod 54 and the lower shutter 50 decreases as the crank arm 57 approaches the vertical. Further, the torque of the servo motor 55 required to move the lower drive rod 54 and the lower shutter 50 is large when the crank arm 57 is in a nearly horizontal state, and as the crank arm 57 approaches the vertical. It can also be seen that it decreases.
[0079]
Therefore, as shown in FIG. 7A, when the servo motor 55 starts rotating clockwise from the state where the lower shutter 50 is at the bottom dead center, the servo motor 55 generates a large torque. Even if not, the lower drive rod 54 and the lower shutter 50 begin to move upward. At this time, the moving speed of the lower drive rod 54 and the lower shutter 50 is extremely low.
[0080]
As the crank arm 57 approaches horizontal, the moving speed of the lower drive rod 54 and the lower shutter 50 increases, and reaches a maximum when the crank arm 57 is horizontal. Since the lower drive rod 54 and the lower shutter 50 are already moving, it is not necessary for the servo motor 55 to generate a large torque.
[0081]
Next, as the crank arm 57 approaches vertical, the moving speed of the lower drive rod 54 and the lower shutter 50 decreases, and as shown in FIG. It gets very low when it comes close to the point.
[0082]
On the other hand, even if the servomotor 55 does not generate a large torque, the force for moving the lower drive rod 54 and the lower shutter 50 upward increases.
[0083]
Therefore, when the upper sheet holding plate 42 of the upper shutter 40 and the lower sheet holding plate 52 of the lower shutter 50 hold and hold the resin sheet 14 from above and below, the lower sheet holding just before contacting the resin sheet 14 is performed. Since the moving speed of the plate 52 is extremely low, the upper sheet gripping plate 42 and the lower sheet gripping plate 52 do not impact each other. Further, since the resin sheet 14 hanging down is not lifted at a high speed, the resin sheet 14 does not overshoot due to inertia. Further, since the resin sheet 14 is gripped with the upper sheet gripping plate 42 by the strong upward force of the lower sheet gripping plate 52, no positional deviation occurs.
[0084]
Further, the position of the top dead center of the lower shutter 50 can be changed by changing the range of the reciprocating angle of the servo motor 55.
[0085]
Therefore, even if the upper mold 33 and the lower mold 35 of the thermoforming machine 30 are exchanged or the resin sheet 14 is changed to one having a different thickness, it is necessary to change the position of the top dead center. It is possible to easily cope with the problem by simply changing the rotation angle of the servo motor 55. In this case, the position of the top dead center can be changed in units of 0.1 [mm].
[0086]
In general, since the movement amount of the upper shutter 40 is shorter than the movement amount of the lower shutter 50, it is not necessary to increase the operation speed. Therefore, even if driven by the drive cylinder device 45, no particular problem occurs.
[0087]
Furthermore, even if the amount of movement of the lower shutter 50 becomes a predetermined value or more and the upper shutter 40 is pushed upward, if the drive cylinder device 45 is formed of an air cylinder, the drive cylinder device 45 is Since the movement of the sheet gripping plate 42 is absorbed, there is no possibility that an excessive force is applied to members such as the lower sheet gripping plate 52 and the upper sheet gripping plate 42.
[0088]
However, if necessary, the upper shutter 40 can be driven by a servo motor and a link mechanism in the same manner as the lower shutter 50 instead of the drive cylinder 45.
[0089]
As described above, in the present embodiment, the lower shutter 50 including the lower support member 51, the lower sheet grip plate 52, and the lower heat seal plate 53 has a lower drive rod when the servo motor 55 rotates. 54, and a link mechanism comprising a connecting rod 56 and a crank arm 57 are integrally moved up and down.
[0090]
Therefore, when the upper sheet holding plate 42 of the upper shutter 40 and the lower sheet holding plate 52 of the lower shutter 50 hold the resin sheet 14 from above and below, the reproducibility of the operation of the lower shutter 50 is extremely high. Since it is always moved upward at a predetermined timing, the timing at which the thermoforming machine 30 clamps and the timing at which the upper sheet gripping plate 42 and the lower sheet gripping plate 52 grip the resin sheet 14 from above and below are misaligned. There is no end.
[0091]
In addition, since the speed of the operation of the lower shutter 50 is high, it is possible to cope with the speeding up of the thermoforming line of the resin sheet 14.
[0092]
Furthermore, since the moving speed of the lower shutter 50 immediately before the lower sheet holding plate 52 contacts the resin sheet 14 is extremely low, the upper sheet holding plate 42 and the lower sheet holding plate 52 abut on each other in shock. There is no. Further, since the resin sheet 14 hanging down is not lifted at a high speed, the resin sheet 14 does not overshoot due to inertia.
[0093]
The resin sheet 14 is gripped between the resin sheet 14 and the upper sheet gripping plate 42 by the strong upward force of the lower sheet gripping plate 52, so that no positional deviation occurs.
[0094]
Further, since the position of the top dead center of the lower shutter 50 can be changed by changing the range of the reciprocating angle of the servo motor 55, the upper mold 33 and the lower mold 35 of the thermoforming machine 30 are exchanged. Even if it is necessary to change the position of the top dead center as in the case where the resin sheet 14 is changed to one having a different thickness, it can be easily handled by changing the rotation angle of the servo motor 55. be able to. In this case, the position of the top dead center can be changed in units of 0.1 [mm].
[0095]
Next, a second embodiment of the present invention will be described. The description of the same structure and the same operation as those in the first embodiment will be omitted.
[0096]
FIG. 8 is a view showing a main part of the link mechanism in the second embodiment.
[0097]
In the figure, 58 is a crank arm fixed to the shaft of the servo motor 55. The crank arm 58 is substantially fixed to the shaft of the servo motor 55 in the vicinity of the center, the end of the connecting rod 56 is rotatably connected to one end thereof, and the counterweight 59 is fixed to the other end. Yes.
[0098]
Thus, in the present embodiment, the counterweight 59 is fixed to the crank arm 58 fixed to the shaft of the servo motor 55.
[0099]
Therefore, even when the servo motor 55 starts to rotate clockwise from the state where the lower shutter 50 is at the bottom dead center, the servo motor 55 does not need to generate a large torque, and the lower shutter 50 50 can begin to move upward.
[0100]
Next, a third embodiment of the present invention will be described. The description of the same structure and the same operation as those of the first and second embodiments will be omitted.
[0101]
FIG. 9 is a diagram showing a main part of the link mechanism in the third embodiment.
[0102]
In the figure, reference numeral 60 denotes a cam fixed to the shaft of the servomotor 55, and a cam groove 61 is formed on one surface.
[0103]
Reference numeral 63 denotes a connecting rod whose upper end (not shown) is connected to the lower end of the lower drive rod 54. In this case, the connecting rod 63 may be formed integrally with the lower drive rod 54. A protrusion extending in the lateral direction is formed at the lower end of the connecting rod 63, and the protrusion slides in the cam groove 61. Reference numeral 62 denotes a guide for preventing the connecting rod 63 from being displaced in the lateral direction.
[0104]
As a result, the projection of the connecting rod 63 moves in the vertical direction along the shape of the cam groove 61 of the cam 60, and moves in the vertical direction along with it.
[0105]
Here, when the angular velocity of the servo motor 55 is constant, the cam groove 61 is in a state where the vertical position of the lower shutter 50, that is, the vertical position of the connecting rod 63 is close to the bottom dead center. The moving speed of the connecting rod 63 is low, and then the moving speed of the connecting rod 63 is high. When the connecting rod 63 approaches the top dead center, the moving speed of the connecting rod 63 decreases. Yes.
[0106]
Therefore, even if the servomotor 55 does not generate a large torque, the lower drive rod 54 and the lower shutter 50 start to move upward. Further, since the operating speed of the connecting rod 63 is high, the operating speed of the lower shutter 50 is increased. Then, the moving speed of the lower sheet gripping plate 52 just before coming into contact with the resin sheet 14 becomes extremely low.
[0107]
Thus, in the present embodiment, the projection of the connecting rod 63 slides in the cam groove 61 of the cam 61 fixed to the shaft of the servo motor 55.
[0108]
Therefore, the structure of the link mechanism is simple and compact. Furthermore, the speed pattern of the operation of the lower shutter 50 can be easily changed simply by changing the shape of the cam groove.
[0109]
In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.
[0110]
【The invention's effect】
  As described above in detail, according to the present invention, the shutter device for a thermoforming machine includes an upper mold and a lower mold, and molds a heated resin sheet by clamping the upper mold and the lower mold. In the thermoforming machine, the upper shutter disposed in the resin sheet inlet portion above the resin sheet conveyance path so as to move up and down, and the upper sheet shutter located below the resin sheet conveyance path can be moved up and down. A lower shutter that grips the resin sheet in cooperation with the upper shutter, a servo motor that reciprocates within a predetermined angular range, and a reciprocating rotational motion of the servo motor into a vertical reciprocating motion. A link mechanism for converting and transmitting to the lower shutter.The link mechanism includes a crank arm fixed to the rotation shaft of the servo motor, a connecting rod rotatably connected to the end of the crank arm, and the angular velocity of the servo motor is constant. The moving speed of the lower shutter is low when the lower shutter is near the bottom dead center and near the top dead center, and when the lower shutter is between the bottom dead center and the top dead center Configured to be high.
[0111]
In this case, when the upper shutter and the lower shutter grip and hold the resin sheet 14 from above and below, the reproducibility of the operation of the lower shutter is extremely high and is always moved upward at a predetermined timing. There is no deviation between the timing at which the machine clamps and the timing at which the upper and lower shutters sandwich the resin sheet from above and below.
[0112]
In addition, since the operation speed of the lower shutter is high, it is possible to cope with an increase in the speed of the thermoforming line for the resin sheet.
[0113]
  Furthermore, since the position of the top dead center of the lower shutter can be changed by changing the rotation angle of the servo motor, the upper mold and the lower mold of the thermoforming machine can be exchanged, or the resin sheet can be of a different thickness. Even if it is necessary to change the position of the top dead center of the lower shutter as in the case of changing to a thing, it can be easily dealt with by changing the rotation angle of the servo motor.
Furthermore, since the moving speed of the lower shutter immediately before the lower shutter contacts the resin sheet becomes extremely low, the upper shutter and the lower shutter do not come into contact with each other in an impact. Further, since the resin sheet with the lower shutter hanging down is not lifted at a high speed, the resin sheet does not overshoot upward due to inertia.
Furthermore, with a simple configuration, the reciprocating rotary motion of the servo motor can be converted into a linear reciprocating motion in the vertical direction.
[0114]
Another shutter device for a thermoforming machine further includes a cylinder device that reciprocates the upper shutter.
[0115]
In this case, the reproducibility of the operation of the upper shutter is extremely high, and the upper shutter is always moved upward at a predetermined timing. Therefore, the timing when the thermoforming machine clamps and the upper shutter and the lower shutter sandwich the resin sheet from above and below. There is no deviation from the timing of gripping.
[0118]
  In still another shutter device for a thermoforming machine, the link mechanism is further provided.BeforeLower drive rod that can move in the vertical direction to transmit linear reciprocating motion to the lower shutterThe connecting rod is rotatably connected to the lower end of the lower drive rod.
[0119]
In this case, it is possible to convert the reciprocating rotary motion of the servo motor into a vertical linear reciprocating motion with a simple configuration.
[0120]
In still another thermoforming machine shutter device, the crank arm has a counterweight fixed to the end opposite to the end to which the connecting rod is connected.
[0121]
In this case, even when the servo motor starts rotating from the state where the lower shutter is at the bottom dead center, the servo motor does not need to generate a large torque and starts to move the lower shutter upward. Can do.
[Brief description of the drawings]
1 is an AA arrow view of FIG. 3;
FIG. 2 is an overall side view of the thermoforming machine and the heating apparatus for the thermoforming machine in the first embodiment of the present invention.
FIG. 3 is a conceptual diagram of a main part showing a side surface of a thermoforming machine and a side cross section of a heating device for a thermoforming machine in the first embodiment of the present invention.
4 is an enlarged cross-sectional view taken along the line B-B in FIG. 1;
FIG. 5 is an enlarged view of a portion C in FIG.
6 is an enlarged view of a part D in FIG. 4;
FIG. 7 is a diagram illustrating a state in which a servo motor rotates and a lower shutter is moved up and down by a link mechanism.
FIG. 8 is a diagram illustrating a main part of a link mechanism according to a second embodiment.
FIG. 9 is a diagram illustrating a main part of a link mechanism according to a third embodiment.
[Explanation of symbols]
14 Resin sheet
30 Thermoforming machine
54 Lower drive rod
55 Servo motor
56, 63 Connecting rod
57, 58 Crank arm
59 Counterweight
60 cams

Claims (4)

(A) An upper mold and a lower mold are provided, and the resin sheet inlet portion of a thermoforming machine that molds a heated resin sheet by clamping the upper mold and the lower mold is moved up and down above the conveyance path of the resin sheet. A possible upper shutter, and
(B) a lower shutter that is arranged to be movable up and down at a position facing the upper shutter below the resin sheet conveyance path, and that grips the resin sheet in cooperation with the upper shutter;
(C) a servo motor that reciprocates within a predetermined angle range;
(D) a reciprocating rotational motion of the servomotor is converted into linear reciprocating motion in the vertical direction have a link mechanism for transmitting the lower shutter,
(E) The link mechanism includes a crank arm fixed to the rotation shaft of the servo motor, a connecting rod rotatably connected to the end of the crank arm, and a constant angular velocity of the servo motor. When the lower shutter is in the vicinity of the bottom dead center and the top dead center, the moving speed of the lower shutter is low, and when the lower shutter is in the middle position between the bottom dead center and the top dead center A shutter device for a thermoforming machine, characterized in that it is configured to be high . The shutter device for a thermoforming machine according to claim 1, further comprising a cylinder device that reciprocates the upper shutter. The link mechanism, the front SL comprises a lower drive rod movable in a vertical direction for transmitting the linear reciprocating motion to the lower shutter, said connecting rod is rotatably connected to the lower end of said lower drive rod The shutter device for a thermoforming machine according to claim 1 or 2 . The thermoforming machine shutter device according to claim 3 , wherein a counterweight is fixed to an end portion of the crank arm opposite to an end portion to which the connecting rod is connected.

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