JP4268082B2 - Roll-on capping method and apparatus - Google Patents

Description

  The present invention is a bottomed cylindrical screwless cap (hereinafter referred to as a cap) formed as a cap in a container with a reseal function such as a bottle-shaped can in which a threaded portion (male thread) is formed in advance in a metal container mouth portion. The present invention relates to a capping method and an apparatus in which a thread portion (female screw) is formed on and attached to a peripheral surface of the cap.

  Usually, the metal cap of a container is comprised from the top plate part and the skirt part hanging from the outer periphery. Then, a cap is put on the container mouth portion, and then pressed from the outer peripheral side of the cap skirt portion by a screw forming roll, and a screw portion that matches the screw portion of the container is formed on the cap. As a capping device for roll-on capping with the cap placed on the container mouth as described above, those disclosed in Patent Document 1 and Patent Document 2 are conventionally known.

  These have a forming head that moves vertically up and down with respect to the forming table, and pressure from above is applied to the cap top plate, and the spindle unit is rotated around the cap skirt to cover the container mouth. The cap portion is configured to perform capping while forming a screw portion in the portion and by narrowing the skirt skirt portion of the cap inward. That is, the screw forming roll is pressed from the outer peripheral side of the cap to perform screw forming, and the hem fastening roll is pressed to the lower side of the annular convex portion of the container mouth portion to perform the skirt fastening.

  The screw forming roll and the skirt tightening roll are moved by moving a conical cone cam up and down to move back and forth with respect to the central axis of the forming head to apply a controlled radial force. Such a movement in the radial direction is generally performed by a conventionally known screw forming roll opening / closing mechanism and skirt fastening roll opening / closing mechanism. Then, the screw forming roll is pressed from the outer peripheral side of the cap, the cap peripheral surface is rolled along the male screw provided at the container mouth, a predetermined female screw is formed on the cap peripheral surface, and the hem The fastening roll is pressed and rolled along the lower surface of the annular convex portion, and a predetermined stationary fastening portion is drawn at the lower end of the skirt portion.

  The structure of the forming head is usually 2 or 2 or more thread forming rolls for screw forming of the cap, and 2 or 2 or more hem tightening for skirt tightening by narrowing the skirt skirt of the cap inward. The rolls are provided alternately and at almost equal intervals. The movement of these rolls in the radial direction is performed by the above-described vertical movement of the cone cam.

  As the target cap in this type of apparatus, a cap having good workability made of an aluminum alloy or a steel thin plate is used. Therefore, the pressing force for pressing the screw forming roll and the skirt fastening roll against the cap is generated by an elastic member such as a torsion spring.

  Further, the screw forming roll opening / closing mechanism and the fastening roll opening / closing mechanism move the screw forming roll and the hem fastening roll toward the center side of the forming head by the vertical movement of the cone cam in the axial direction, and contact the cap with the screw forming roll and The skirt tightening roll presses the circumferential surface of the cap by the elastic force of each torsion spring to perform screw forming and hem tightening forming.

  However, in the conventional method, when the screw forming roll and the hem fastening roll are separated from the cap after forming, the screw portion formed on the cap by the elasticity of the cap material, such as aluminum, is spring-backed to the screw portion of the container mouth portion. There is a problem in that when the inner pressure of the container rises or the impact is dropped, the sealing performance between the container and the cap deteriorates and leakage easily occurs.

  In order to reduce the amount of such spring back, it is conceivable to increase the pressing force of the forming roll. However, in the case of a reseal container such as a metal bottle-shaped can made of thin metal, a rigid glass bottle If the screw forming roll is pressed against the circumference of the cap with a strong pressing force unlike the cap, the cap and the container mouth will be deformed by the pressing force, and it will be easy to cause unsuccessful opening and sealing failure. Cannot be applied.

  In response to this problem, Patent Document 3 discloses a so-called “2” in which a forming head (clamping head) is controlled by an operation cam to re-form a screw portion so that the screw portion and the bottom fastening portion are in close contact with the container mouth portion. A technique of “turning”, that is, forming a screw portion by tightly adhering to a screw portion of a container mouth portion by winding the cap in two turns and tightening.

In addition, in the capping device that winds twice during the transportation of the container, the pressing force of the screw forming roll against the cap is made different between the first time and the second time so as not to apply an excessive force to the mouth and the cap of the container. Patent Document 4 also describes a device that winds twice with a predetermined pressing force. This apparatus changes the cam track formation position (height) by providing a lower cam (cam track) that moves the cone cam up and down separately from an upper cam (cam track) that moves the forming head (capping head) up and down. It is a thing.
JP-A-53-137771 JP-A-47-41979 JP 58-203888 A JP 2001-301889 A

  However, in the case of winding twice with one operating cam (single cam) as in Patent Document 3, before a predetermined pressing force (hereinafter referred to as a capping pressure) is applied to the cap top plate portion (that is, a predetermined cam). Before the capping pressure is reached, the screw forming roll and the hem fastening roll come into contact with the cap, and the molding starts, and the cap is inclined to easily cause a winding failure.

  On the other hand, in Patent Document 4, an upper cam for moving the forming head (capping head) up and down and a lower cam for moving the cone cam up and down are provided separately. Since the screw forming roll and the hem fastening roll do not come into contact with the cap before reaching, the problem with the single cam is solved temporarily. Also, during the transportation of the container, the container mouth can be deformed or the cap can be divided into multiple times with a predetermined pressing force so that excessive force is not applied to the container mouth or cap by pressing the screw forming roll against the cap. There is a description in Patent Document 4 that it is possible to prevent scratches.

  However, after the first screw forming, when the screw forming roll is separated from the cap, the pressure unit holding the top plate of the cap is moved upward so that the pressure unit is separated from the cap top plate. Therefore, when spring back is performed with the first thread forming, the pressing force of the first thread forming roll is set so weak that it does not deform the cap or the container mouth, so the thread is the container mouth In this case, the adhesive force (contact load) between the liner member of the cap and the container mouth portion is reduced, and even if the second screw molding is performed, Even if the screw forming roll is pushed in, the material is not drawn more than the first time, so that the second time of screw forming is performed in a state where the adhesive force between the liner member and the container mouth portion is reduced. Recovery of adhesion cannot be expected. As a result, sealing is performed when the internal pressure of the can rises after filling and sealing the contents (for example, during sterilization processing such as retort processing) or when a drop impact occurs during the distribution of canned food. There is a problem that has not been solved yet, such as being prone to defects.

An object of the present invention is to eliminate the above-described problems. Specifically, when a cap is attached to a container mouth by a roll-on capping method, a plurality of screw forming operations are performed while the container is being transported. In this case, the screw forming dimension can be stabilized and the cap can be sealed against the container mouth even in the case of a metal container in which the container mouth is easily deformed. The purpose is to prevent sealing failure when the internal pressure of the can rises after filling and sealing the contents, or at the time of a drop impact in the distribution process of canned food.

To achieve the above object, a first aspect of the invention, the screws forming roll capping pressure on the top plate portion of the metallic pilfer-proof cap covering the mouth of the container in the state was pressurized example thereabout After rolling and forming the female screw part along the male screw part of the container mouth part on the peripheral surface of the cap, the screw forming roll is once separated from the cap, and the same screw forming roll is again attached to the peripheral surface of the cap. In the capping method of re-forming the female thread portion by pressing, the screw-forming roll is moved to the radially inner side as the cone cam is lowered, and the screw-forming roll is rolled to the peripheral surface of the cap for the first time. After the screw forming is performed, while the cone cam is further lowered and the driven member is moved outward in the radial direction so that the screw forming roll is once separated from the cap, the driven member has a radius by an elastic force. The reaction force against the driven member from the cone cam by being pressed against the direction inward, until just before the second thread forming is started continues causing downward in the axial direction of the driven member, the top plate portion of the caps The capping method is characterized in that the pressing force is maintained at least equal to or higher than the capping pressure of the top plate portion of the cap during the first screw forming.

On the other hand, the invention according to claim 2 is a molding table on which a container is placed around a fixed shaft and rotated and conveyed in the horizontal direction, and a plurality of the table that is integrally connected to the molding table and rotates in the horizontal direction around the fixed shaft. A frame turret, a pressurizing unit which is arranged to be movable up and down above the forming table, raises and lowers the forming head relative to the forming table, and applies a capping pressure to the top plate portion of the cap, and a shaft of the pressurizing unit On the other hand, the screw forming roll is moved radially inward, and the screw forming roll rotates around the metal pill fur proof cap placed on the mouth portion of the container, along the male thread portion of the mouth portion of the container. A spindle unit that forms a female thread portion on the peripheral surface of the cap, a cylindrical upper cam that raises and lowers the pressure unit and the spindle unit, and the spindle unit. In a capping device comprising a cone cam for moving the screw forming roll in the radial direction via a driven member and a cylindrical lower cam for raising and lowering the cone cam, cam tracks of the lower cam and the upper cam are arranged side by side, The lower cam track moves up and down the cone cam in accordance with the vertical movement of the molding head composed of the pressurizing unit and the spindle unit, and projects downward from the lift track to lower the cone cam and follow it. A molding track that moves the member inward in the radial direction and moves the screw forming roll that moves integrally with the driven member inward in the radial direction, and projects downward from the molding track at an intermediate position of the molding track. The cone cam is further lowered, and the screw forming roll is moved through the driven member. The cone cam has a curved constricted portion formed at a central portion thereof, a downwardly inclined portion extending downward and outward from the constricted portion, and an upwardly extending from the constricted portion and An upwardly inclined portion extending outward, and the driven member is configured to engage with the upwardly inclined portion within a range that does not deviate upward beyond the upwardly inclined portion at the lowest descending position of the cone cam. It is the capping device characterized by being made.

The invention of claim 3 is Oite to claim 2, the inclination angle with respect to the central axis of the cone cam of the upper inclined portion, a capping device which is a range of 10 degrees to 20 degrees.

  According to the capping method of the present invention, a resealing container such as a metal bottle-shaped can that is easy to deform the container mouth portion while avoiding loosening of the screw portion by carrying out screw forming a plurality of times while the container is being conveyed. Even in this case, it is possible to stabilize the thread forming dimensions, improve the sealing performance of the cap against the container mouth, and when the internal pressure of the can rises after filling and sealing the contents, It becomes possible to prevent a sealing failure at the time of a drop impact in the distribution process.

  Further, according to the capping device of the present invention, the cone cam can be moved up and down with a simple configuration that does not require any special operating means, so that the screw molding can be performed in a plurality of times. In addition to being easy to handle, when the screw forming roll is once separated (intermediately separated) from the cap after the first screw forming, the cone cam is further lowered to apply a force to move the cam follower radially outward. When the screw forming roll is moved away from the cap by applying a downward pressing force, the cam head is connected to the cam follower to prevent the forming head from moving up and down and press the cap top plate during separation. The plugging pressure of the pressure unit is prevented from lowering at least than the state at the time of the first screw forming. As a result, even if the first molded screw part is spring-backed, the second screw molding can be performed without lowering the sealing function between the cap and the container mouth part at the time of intermediate separation. Therefore, even when the internal pressure of the can rises after filling and sealing the contents, or when a drop impact is received in the distribution process of the can, sealing failure can be prevented.

  Hereinafter, the capping method and apparatus of the present invention will be described in detail with reference to specific examples.

  The capping method and apparatus of the present embodiment relates to capping in which a metal pilfer proof cap provided with a resin sealing liner is attached to the mouth of a reseal can by roll-on molding. As shown in FIG. 1, the cap 1 before being attached to the container mouth portion by roll-on molding is formed with a screw portion on a skirt portion 13 that hangs downward from the periphery of the cap top plate portion 11 via a corner portion 12. The portion to be left is left as a cylindrical portion 14, and a pilfer proof band 16 is formed at the bottom of the cylindrical portion 14 so as to be separated by the weakening portion 15. A sealing resin liner member 2 is integrally attached to the inner surface side of the top plate portion 11 of the cap 1.

  On the other hand, as shown in FIG. 2, the container body to which the cap 1 is mounted is a can container 30 having a screwed mouth portion 3 that can be resealed (replugged) by the cap 1, and is manufactured from a sheet metal. A curled portion 31 having a circular cross-section or a multilayer folded structure is formed at the upper end of the mouth portion 3 of the can container 30, and an inclined wall 32 that extends downward is provided below the curled portion 31. Thus, a male screw portion 33 for screwing the cap 1 is formed, and an annular projecting portion 34 for locking the pilfer proof band 16 of the cap 1 is formed below the male screw portion 33.

  The metal material of the cap 1 is not particularly limited. For example, it has been conventionally known, for example, an aluminum alloy plate coated with an epoxy-phenol resin in which an olefin resin powder is dispersed on the inner surface side. A metal material for the cap is used. The resin material of the sealing liner member 2 is a conventionally known liner such as a blend material of low density polyethylene and ethylene-propylene copolymer synthetic rubber, a blend material of polypropylene and styrene elastomer, a polyester elastomer, and the like. Resin materials for members are used. The sealing liner member 2 is formed by a well-known embossing method or the like in which a resin material is extruded in a molten state onto the inner surface side of the top plate portion 11 of the cap 1 and embossed. Moreover, the can container 30 which is a container main body is formed from a metal plate such as an aluminum alloy plate or a steel plate, for example, and the body portion and the bottom portion are integrally formed from, for example, a polyester-coated metal plate coated with a polyester film thermally bonded on both sides. It is molded (or a bottom lid made as a separate body may be wound around the body).

  By the way, when the cap 1 in which the screw part shown in FIG. 1 is not formed is attached to the container mouth part 3 shown in FIG. 2, it will be described later in a state where the cap 1 is put on the container mouth part 3 from above. By using such a capping device, the container mouth portion 3 is placed on the cylindrical portion 14 of the skirt portion 13 of the cap 1 by roll-on molding using a screw-forming roll while applying a stoppering pressure to the top plate portion 11 of the cap 1. A female screw portion is formed so as to match the male screw portion 33, and the lower end portion of the pilfer proof band 16 formed on the skirt portion of the skirt portion 13 of the cap 1 is formed in an annular shape of the container mouth portion 3 by a skirt tightening roll. The hem is tightened so as to engage with the lower end of the protrusion 34.

  As shown in FIGS. 3 and 4, the capping device of the present invention includes a spindle unit 42 having a screw forming roll 40 and a hem fastening roll 41, and a pressure unit incorporating a cap pressing push pin (not shown). And a molding head 44 composed of 43. As shown in FIG. 4, it is arranged on the central axis of the forming head 44 and is elastically held in a state of being biased downward by a spring 71 (plugging pressure generating means), and in the vertical direction according to an upper cam described later. A spindle shaft on which a spindle unit 42 having a screw forming roll 40 and a hem fastening roll 41 rotates so as to revolve outside the pressure rod 45 around the central axis of the forming head 44 as a rotation center with respect to the moving pressure rod 45. 49 and a pressure unit 43 is provided at the lower end of the pressure rod 45.

  Further, the outline of this capping device is shown. The capping device is configured to perform capping in the process of turning and transporting the container 30 around the fixed shaft 46, and the molding table that rotates around the fixed shaft 46. 47 is provided, and the molding head 44 is disposed above the molding table 47 so as to be vertically movable.

  Above the molding table 47 described above, a frame turret 48 that rotates integrally with the molding table 47 about the fixed shaft 46 is provided. The above-described molding head 44 is disposed above the container 30 held by the molding table 47 on the outer periphery of the frame turret 48.

Further, as shown in FIG. 4, a molding head 44 attached to the lower end portion of a spindle shaft 49 which is moved up and down with respect to the container 30 on the molding table and rotated by a rotation drive mechanism (not shown), and its spindle A cone cam 51 is disposed outside the shaft 49 and attached to the lower end of a sleeve 50 that moves up and down. On the other hand, the pressure block 52 of the pressurizing unit 43 is attached to the lower end portion of the pressure rod 45 disposed inside the spindle shaft 49 so as to be reciprocally movable in the vertical direction.

  In this way, two or more screw forming rolls 40 and two or more hem fastening rolls 41 are alternately arranged, and each roll 40, 41 is moved to the central axis of the forming head 44 by the vertical movement of the cone cam 51. On the other hand, it is configured to move back and forth in the radial direction. Further, the screw forming roll shaft 53 and the bottom fastening roll shaft 54 are held by the forming head 44 so as to be rotatable with their respective axis lines directed in the vertical direction. A cam follower (driven member) that comes into contact with the cone cam 51 at the tip of the upper arm 55 is attached to both the upper and lower ends of the screw forming roll shaft 53 in a state of protruding in the radial direction. 57 is attached. Further, the screw forming roll 40 is held at the tip of the lower arm portion 56 so that its axis is directed in the vertical direction and is rotatable. Similarly, arm portions 58 and 59 are attached to both upper and lower ends of the hem fastening roll shaft 54 in a state of projecting in the radial direction, respectively, and a cam follower (driven) that contacts the cone cam 51 at the distal end portion of the upper arm portion 58. Member) 60 is attached. Further, a hem fastening roll 41 is held at the tip of the lower arm portion 59 so that its axis is directed in the vertical direction and is rotatable.

  Further, between the screw forming roll shaft 53 and a predetermined fixing portion of the forming head 44, the cam followers 57 and 60 are in a direction approaching the cone cam 51, and the screw forming roll 40 and the hem fastening roll 41 are respectively caps 1. Are provided with torsion coil springs 61 and 62 for applying a torsional force to the screw forming roll shaft 53 and the fastening roll shaft 54, respectively.

  On the other hand, as shown in FIG. 4, the cone cam 51 has a curved constricted portion 51A at the center, a lower inclined portion 51B is connected to the lower side of the constricted portion 51A, and the constricted portion 51A is interposed therebetween. The upper inclined portion 51C is connected to the upper side.

  Note that the inclination angle (θ) of the upper inclined portion 51C depends on the number of cam followers 57 and 60 installed around the cone cam 51, the set value of the pressing force (side load) of the screw forming roll 40, and the curl of the container mouth portion 3. Generally, 4 to 6 cam followers 57 and 60 for the screw forming roll 40 and the hem fastening roll 41 are generally provided, and the cap is conventionally used at the time of intermediate separation. Since the amount (200N to 300N) in which the capping pressure to the top plate portion 11 is reduced is shared by the number of cam followers, it is appropriately determined in the range of 10 to 20 ° with respect to the central axis of the cone cam. If the inclination angle (θ) is smaller than 10 °, the decrease in contact load between the liner member 2 and the upper surface of the curled portion 31 of the container mouth portion 3 at the time of intermediate separation cannot be compensated, and the amount of movement of the cone cam is small. This increases the size of the device, which is undesirable. On the other hand, if the angle is larger than 20 °, the container mouth portion 3 is likely to be buckled. Therefore, the angle is set in the range of 10 ° to 20 ° with respect to the central axis of the cone cam. More preferably, it is in the range of 10 ° to 15 °. In addition, in the case of a narrow laminated curl shape that is folded back vertically with a relatively small contact area with the surface of the curled portion of the liner member, it is more susceptible to the spring back of the screw portion than in the case of a wide width. Therefore, it is effective to select a larger inclination angle.

  As shown in FIGS. 3 and 5, the screw forming roll 40 is connected via an upper cam 63 that is a cylindrical cam that moves the pressure unit 43 and the spindle unit 42 up and down, and a cam follower 57 that is attached to the spindle unit 42. A lower cam 64 for moving the cone cam 51 up and down for moving the cam in the radial direction is provided around the fixed portion 70. These cams 63 and 64 are cylindrical groove cams. Cam followers 63A and 64A are engaged with the cams 63 and 64, respectively. The spindle shaft is moved up and down in accordance with the movement of the upper cam follower 63A, and the sleeve is moved up and down in accordance with the movement of the lower cam follower 64A.

  The upper cam 63 and the lower cam 64 will be described. The upper cam 63 includes an elevating orbit (AB, MN) for raising and lowering the molding head 44, and a stopper trajectory (BM) for pressing the cap top plate (the cap while applying the stoppering pressure). The corner portion may be deformed). One lower cam 64 is arranged side by side with the upper cam 63, and its orbit is raised and lowered (AB, MN) for moving the cone cam 51 up and down as the forming head 44 moves up and down, and the cone cam 51 is raised and lowered. The cam follower 57 is moved inward in the radial direction, the screw forming roll 40 that moves integrally with the cam follower 57 is pressed against the peripheral surface of the cap, and screw forming tracks (DE, HJ) are formed. Then, at an intermediate position between the first and second trajectories of the screw forming trajectory, an intermediate separation that protrudes further downward from the screw forming trajectory and further lowers the cone cam 51 to separate the screw forming roll 40 from the cap once. Orbit (E-H).

  Next, a capping method using the above-described apparatus of the present embodiment will be described below.

  The capping method of the present embodiment is a capping method in which the screw molding and the skirt fastening molding are performed a plurality of times while the top plate portion of the cap is being pressed while the molding table goes around. Usually, when winding is performed a plurality of times, in order to prevent deformation of the cap and the container mouth portion, screw molding and stationary molding are performed without applying a strong pressing force (side load) at the first time. Therefore, when the screw forming roll and the hem fastening roll are once separated from the cap by performing the first screw forming, the spring back of the formed screw portion is large, resulting in loosening of the screw portion, and the container mouth portion and A decrease in the adhesion of the liner member is likely to occur.

  In addition, after the first molding is performed on the peripheral surface of the cap, if the pressure unit is also released when the screw forming roll is once separated from the cap, the cap applied during the first screw molding is applied. The plug pressure is lost, and as a result, the screw portion is loosened and the contact pressure of the liner member is also lowered. For this reason, in this embodiment, it is assumed that the top plate portion of the cap is kept pressed even when the screw forming roll is once separated from the cap.

  The cause of the decrease in sealing performance will be discussed below. First, in the screw forming process, the screw part (female screw) formed on the cap is not formed with a uniform screw depth in the lead direction, and the screw part is formed on the lower side of the cap. It has been found that the upper thread portion formed first is pulled, and as a result, the upper screw depth tends to be formed shallower than the lower screw depth. This phenomenon appears strongly when screw molding and skirt fastening are performed in the same process.

  In other words, at the initial stage of screw forming, the material is drawn from the top plate portion of the cap to the skirt portion side, pulling force acts on the corner portion of the cap, and between the curled portion of the container mouth portion at the cap corner portion. A liner member is compressed, and the contact load of the liner member against the curled portion increases, but as the screw forming progresses and the screw forming roll moves downward along the male screw, the material of the already formed screw portion is reduced. Pulled to form the lower screw, the groove shape of the screw portion formed in the initial stage is loosened (the depth of the screw portion is reduced). As a result, it was found by computer structure analysis that the contact load of the liner member is lower than that in the initial stage when the screw forming roll moves downward.

  The decrease in the contact load of the liner member is that although the screw forming roll is pressed against the cap again and the screw portion is re-formed (second screw forming), the screw portion is already shallow in the first screw forming. Therefore, the pulling force of the cap corner is not obtained as much as the first screw forming step, and the decrease in the adhesion force is difficult to recover, and the cap and the container mouth (curl surface) If the cap top plate swells when the internal pressure of the can rises, the contact load is likely to further decrease, and it is presumed that the contact load tends to cause poor sealing.

  Second, it has also been found that it originates from a configuration unique to the capping device. That is, the structure in which the cam follower is moved in the radial direction along with the vertical movement of the cone cam and the screw forming roll is moved closer to and away from the circumferential surface of the cap accordingly has a considerable influence on the sealing function.

  When the cap is wound twice, if the intermediate separation track of the lower cam protrudes upward as in the prior art, the mechanism that raises the cone cam and moves the cam follower radially outward in the intermediate separation step is the first time After screw forming, when the screw forming roll is once separated from the cap (intermediate separation), the cone cam is raised and the cam follower is brought into contact with the inclined surface of the downward inclined portion extending downward and outward so that the screw forming roll is in the radial direction. At that time, the cam follower is subjected to a vertical component force that pushes upward due to impact or frictional resistance with the slope, and force is applied in the direction of floating the spindle unit itself having the cam follower. The spindle shaft and the bearing that supports the spindle shaft with the upward component force acting on the spindle unit. Through the grayed (corresponding to the bearing 65 of FIG. 4) to lower the capping pressure cap float against the pressure rod presses the top plate portion of the cap the spring 71 upward.

  In this way, when the screw forming roll is once separated from the cap on the intermediate separation track, if the capping pressure of the cap is released or lowered, the adhesion force between the liner member and the surface of the curled portion is reduced, resulting in poor sealing. It can be assumed that it is easy to wake up.

  Therefore, in the present invention, the screwing pressure applied to the cap top plate portion is set so as not to reduce the contact load of the liner member 2 at the same time when the screw forming roll moves backward after the first screw forming or immediately before the end of the first screw forming. It is important to maintain or increase the value so that the second screw forming can be performed.

  In the present embodiment, as shown in FIG. 4, the cam follower 57 is moved radially outward in the intermediate separation step so that the screw forming roll 40 is once separated from the cap so as not to cause various problems as described above. Therefore, the operation of the cone cam 51 is made different from the conventional one, and the cone cam 51 is lowered to move the cam follower 57 radially outward along the upper inclined portion 51C formed above the constricted portion 51A. Then, as shown in FIG. 7, the capping pressure of the cap top plate portion is increased between the tracks E-H of the lower cam 64.

  More specifically, FIG. 5 shows a series of states from the state before the start of the molding process to the end as a development view, and FIG. 6 shows the change in the relative position between the cone cam 51 and the cam follower 57. Is schematically shown. First, the can container 30 is supplied to the holding portion of the molding table 47 by a predetermined infeed turret (not shown) and held in an upright state. In this state, the molding head is pulled upward, and the cap 1 is put on the mouth of the can container 30. Furthermore, each roll 40, 41 is retracted outward (open) in the radial direction.

  When the molding table 47 and the spindle unit are rotated by a predetermined angle about the fixed axis from this state, the upper cam 63 and the lower cam 64 are aligned and inclined downward (track A-B), so the spindle unit. As a whole descends toward the can container 30. Then, a downward punching pressure is applied from the pressure block 52 to the top portion of the cap 1 that is previously placed on the mouth portion, and the corner portion and the like are drawn into a predetermined shape.

  At the subsequent rotational position (phase), there is no change in the shape of the upper cam 63 (trajectory B-M), and the lower cam 64 is first displaced downward (track A-B). ). For this reason, the cam follower 64A engaged with the lower cam 64 and the sleeve integral therewith move downward. A cone cam 51 is provided at the lower end of the sleeve. The cone cam 51 is configured such that the peripheral surface follows the cam follower 57 as shown in FIGS. 4 and 6, and a screw is provided at the center of the peripheral surface. A curved constricted part 51A for moving the forming roll 40 inward in the radial direction, a downward inclined part 51B formed so as to extend downward and outward from the constricted part 51A, and upward from the constricted part 51A And an upward inclined portion 51C formed to extend outward.

  On the other hand, since the elastic force of the torsion coil spring 61 described above acts on the screw forming roll shaft 53, the cam follower 57 moves relative to the constricted portion 51A of the cone cam 51, so that the screw forming roll 40 has a radius. It moves inward in the direction and is pressed against the skirt portion of the cap 1. Further, since the entire forming head 44 is rotating, the skirt portion of the cap 1 is deformed by the screw forming roll 40 into a shape along the male screw portion of the mouth portion 3, and the screw forming roll 40 is the male screw portion. Move in a spiral. As a result, a female screw portion having a shape corresponding to the male screw portion is formed in the skirt portion of the cap 1.

  Further, before and after the screw forming, the skirt fastening roll 41 is pressed against the skirt skirt, so that the skirt skirt is drawn so as to wrap around the annular protrusion formed in the mouth 3. That is, the pilfer proof band is drawn.

  At the subsequent rotational position (phase), there is no change in the shape of the upper cam 63, and the lower cam 64 is inclined and displaced downward (trajectory EF). Accordingly, the cone cam 51 is displaced downward, while the cone cam 51 is formed with the upper inclined portion 51C so as to extend upward and outward from the constricted portion 51A, so that the peripheral surface of the constricted portion 51A is elastically applied. The cam follower 57 that has been in contact (a slight gap is formed at the time of screw molding) moves to the outside of the spindle unit 42 in the radial direction. That is, the screw forming roll 40 and the skirt fastening roll 41 are returned to the original positions, that is, the positions separated radially outward from the cap 1.

  In this so-called intermediate separation state, since the cam follower 57 is pressed against the upper inclined portion 51C of the cone cam 51 by an elastic force, a force that presses the cam follower 57 downward in the axial direction is generated as the reaction force. As a result, a pressing force is continuously applied to the spindle unit 42.

  As described above, after the screw molding and the skirt fastening are performed for the first time, the screw molding and the skirt fastening are simultaneously performed again. That is, the lower cam 64 has returned to the position in the axial direction where the first screw forming and the bottom tightening were performed (track GH). Accordingly, the screw forming roll 40 is again brought into contact with the skirt portion subjected to the first screw forming, that is, the screw forming portion (female screw portion), and the second screw forming is performed. At the same time, the skirt fastening roll 41 comes into contact with the skirt skirt portion that has been subjected to the first hem fastening, that is, the skirt fastening portion, and the second skirt fastening is performed (track H-J). .

  At the subsequent rotational position (phase), the lower cam 64 is tilted upward and returned to the original axial position (track J-K), so that each of the screw forming roll 40 and the bottom fastening roll 41 is in the radial direction. Open outward and away from the cap 1.

  In the subsequent rotational position (phase), the upper cam 63 and the lower cam 64 return to the state before the start of molding (track MN), so that the spindle unit 42 is pulled up above the container 30 and the pressure block 52 Is separated from the top plate portion of the cap 1 and the forming process is completed.

FIG. 7 shows the change in the capping pressure with respect to the cap in the molding process described above. In the process of the so-called intermediate separating above, pressed by the elastic force upward inclined portion cam follower is in cone cam, since a downward load associated therewith occurs, Dasen'ni heavy is maintained substantially constant or slightly increased to Yes. On the other hand, in the conventional apparatus and method, as indicated by the broken line, the pressing force is reduced in the intermediate separation step. As described above, in the apparatus and method of the present invention, even if so-called plural windings in the roll-on molding of the threaded portion, the load pressed by the cap does not decrease, so that molding without loosening can be performed.

It is a partial section side view shown partially in a section by cutting out an example of a metal cap to which the capping method of the present invention is applied. It is a partial cross section side view which shows a cross section about an example of the container main body (near the container mouth part) applied to the capping method of the present invention. It is a conceptual diagram which shows the schematic structure of the capping apparatus of this invention. It is a schematic diagram around a forming head in the capping device of the present invention. It is explanatory drawing which shows typically a series of shaping | molding processes by the capping method of this invention. It is explanatory drawing which shows the component force which acts on the cam follower by a cone cam in the series of shaping | molding processes shown in FIG. It is a diagram which shows the relationship of the stoppering pressure with respect to the shaping | molding position in the shaping | molding process shown in FIG .

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Cap, 3 ... Container mouth part, 11 ... Top plate part, 13 ... Skirt part, 33 ... Male screw part, 40 ... Screw forming roll, 42 ... Spindle unit, 43 ... Pressure unit, 44 ... Molding head, 46 ... fixed shaft, 47 ... molding table, 48 ... frame turret, 51 ... cone cam, 51A ... constricted part, 51B ... lower inclined part, 51C ... upper inclined part, 57 ... cam follower (driven member), 63 ... upper cam, 64 ... Lower cam.

Claims (3)

A screw thread is rolled around the top plate part of the metal pilfer proof cap that covers the mouth part of the container, and the female thread along the male thread part of the container mouth part is rolled around it. In the capping method in which the part is formed on the peripheral surface of the cap, the screw forming roll is once separated from the cap, and the same screw forming roll is pressed against the peripheral surface of the cap again to re-form the female screw part.
After the screw forming roll is moved inward in the radial direction as the cone cam is lowered, the screw forming roll is rolled to the peripheral surface of the cap, and after the first screw forming, the cone cam is further moved. While the driven member is moved downward in the radial direction and the screw forming roll is once separated from the cap, the driven member is pressed against the driven member from the cone cam by the elastic force. the reaction force, of the driven member until just before the second thread forming is started continues causing downward in the axial direction, at least the first of said cap when the screw forming the pressing force of the top plate portion of the caps A capping method characterized in that the capping pressure is maintained at a level equal to or higher than the capping pressure of the top plate.   A molding table on which a container is placed around a fixed shaft and rotated and conveyed in the horizontal direction, a plurality of frame turrets that are integrally connected to the molding table and rotate in the horizontal direction around the fixed shaft, and an upper portion of the molding table A pressurizing unit that raises and lowers the forming head relative to the forming table and applies a capping pressure to the top plate of the cap, and a screw forming roll radially inward with respect to the axis of the pressurizing unit. The screw forming roll is rotated around a metal pilfer proof cap that covers the mouth portion of the container, and the female screw portion along the male thread portion of the mouth portion of the container is placed on the peripheral surface of the cap. Via a spindle unit to be molded, a pressure unit and a cylindrical upper cam for raising and lowering the spindle unit, and a driven member attached to the spindle unit. A cone cam moving the screw forming roll radially in the capping device and a cylindrical Roakamu elevating the cone cam,
  A cam track of the lower cam and the upper cam is arranged side by side, and the lower cam track is an elevating track that raises and lowers the cone cam in accordance with the vertical movement of the molding head composed of the pressurizing unit and the spindle unit. A projecting track that projects downward from the lifting track, lowers the cone cam, moves the driven member radially inward, and moves the screw forming roll that moves integrally with the driven member radially inward,
  At an intermediate position of the forming track, an intermediate separating track is formed that protrudes downward from the forming track, further lowers the cone cam, and temporarily separates the screw forming roll from the cap via the driven member.
  The cone cam has a curved constricted portion at a central portion, a lower inclined portion extending downward and outward from the constricted portion, and an upper inclined portion extending upward and outward from the constricted portion. Provided,
  The capping device according to claim 1, wherein the driven member is configured to engage with the upper inclined portion within a range that does not deviate upward beyond the upper inclined portion at the lowest descending position of the cone cam. The angle of inclination with respect to the central axis of the cone cam of the upper inclined portion, key Yappingu device according to claim 2, characterized in that in the range of 10 degrees to 20 degrees.

Images