Title of Invention

A CLAMPING DEVICE FOR BLOW MOLDING MACHINE

Abstract

TITLE: A CLAMPING DEVICE FOR BLOW MOLDING MACHINE. A CLAMPING DEVICE FOR BLOW MOLDING MACHINE, COMPRISING; A FIRST CLAMPING PLATE AND SECOND CLAMPING PLATE ARRANGED FACING EACH OTHER; A PAIR OF SPLIT MOLDS FORMING A BLOW CAVITY MOLD BEING ESPECTIVLEY MOUNTED ON FACING SURFACES OF THE FIRST CLAMPING PLATE AND THE SECOND CLAMPING PLATE A MOVABLE PLATE DISPOSED ON A SIDE OF THE FIRST CLAMPING PLATE OPPOSITE FROM A SIDE ON WHICH THE SECOND CLAMPING PLATE IS DISPOSED; A PLURALITY OF TIE RODS EZXTENDING THROUGH THE FIRST CLAMPING PLATE AND FIXEDLY CONNECTED TO THE MOVABLE PLATE AND THE SECOND CLAMPING PLATE, AND SUPPORTING THE FIRST CLAMPING PLATE MOVABLE BETWEENT HE MOVABLE PLATE ANDTHE SECOND CLAMPING PLATE; ANDA DRIVING DEVICE FOR DRIVING THE MOVABLEPLATE AND THE FIRST CLAMPING PLATE AWAY FROM OR TOWARD EACH OTHER; A POSITIONING MEANS PROVIDED INDEPENDENTLY OF THE DRIVING DEVICE, MVOING THE FIRST CLAMPING PLATE AND THE SECOND CLAMPING PLATE IN SYNCHRONIZATION, AND CONTROLLING THE CLAMPING POSITION OF THE SPLIT MOLDS; WHEREIN THE POSITIONING MEANS IS DISPOSED BETWEENT HE MOVABLE PLATE AND THE FIRST CLAMPING PLATE; WHEREIN THE POSITIONING MEANS COMPRISES A V-SHAPED LINK MEANS WHEREIN THE V-SHAPED LINK MEANS COMPRISES; A CONNECTING SHAFT DISPOSED AT MIDDLE POSITION BETWEENT HE MOVABLE PLATE AND THE FIRST CLAMPING PLATE; A FIRST LINK ARM RATATABLY SUPPORTED BY THE CONNECTING SHAFT ANDTHE MOVABLE PLATE RESPECTIVELY; AND A SECOND LINK ARM ROTATABLY SUPPORTED BYTHE CONNECTING SHAFT ANDTHE FIRST CLAMPING PLATE RESPECTIVELY; WHEREIN THE POSITIONING MENAS COMPRISE A GUI8DE MEMBER WHICH GUIDES THE MOVEMENT OF THE CONNECTING SHAFT IN A DIRECTION CROSSING AN OPENING-AND-CLOSING DIRECTION OF THE SPLIT MOLDS WHEN THE SPLIT MOLDS OPEN OR CLOSE.

Full Text

CLAMPING MECHANISM FOR BLOW MOLDING MACHINE BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a clamping mechanism for blow molding machine and particularly to a clamping mechanism for blow molding machine which can open and close a mold and clamp the mold without creation of any eccentricity. Description of the Related Art In general, the blow molding machine clamps a blow cavity mold by use of a clamping device. The clamping device may comprise, for example, a pair of clamping plates, that is, first and second clamping plates disposed facing each other, on each of which the corresponding one of split molds for defining a blow cavity mold is fixedly mounted. A movable plate disposed on the opposite side of the first clamping plate to the second clamping plate is fixedly connected to the second clamping plate through a tie rod. A driving device is fixedly mounted on the movable plates. The driving device urges the first clamping plate in the clamping direction with its reaction created moving the movable plate in the opposite direction to the first clamping plate. When the second clamping plate connected to the movable plate through the tie rod is moved in the mold closing direction, the mold will be closed and clamped. The blow cavity mold can be opened by actuating the driving means in the reverse direction. In such a clamping device for the blow molding machine, the split molds must simultaneously reach the clamping position on clamping. Otherwise, one of the split molds would abut a preform or a preform carrying member or a bottom mold prior to the other split mold. This may damage the preform or the preform carrying member of the bottom mold. Therefore, both the right and left split molds are required to be synchronized on clamping of the blow cavity mold. US 5698243 although discloses a structure of a mold apparatus but fails to provide a device which is capable of controlling the clamp position of the split mold. US 5388981, US 5698243, US 4449996 and US 4283218 eventhough disclose molding apparatuses but none of them proposes a "V-shaped link", "a connecting shaft", "a guide member", "a movable plate" or "a first and second link arms"which may obviate frequent adjustment of the positioning means. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a clamping device for blow molding machine which can establish the mold closing position independently without associating with the driving means ad can open and close the split molds in synchronization with each other. Another object of the present invention is to provide a clamping device for blow molding machine which can be of a simplified and size-reduced structure for opening and closing the split molds in synchronization, thus reducing the manufacturing cost. One aspect of the present invention provides a clamping device for blow molding machine, comprising: first and second clamping plates each having two sides, and arranged facing each other; a pair of split molds forming a blow cavity mold being respectively mounted on the facing sides of the first clamping plate and the second clamping plate; a movable plate disposed on a side of the first clamping plate opposite from a side on which the second clamping plate is disposed; a plurality of tie rods extending through the first clamping plate and fixedly connected to the movable plate and the second clamping plate, and supporting the first clamping plate movable between the movable plate and the second clamping plate; a driving device for driving the movable plate and the first clamping plate away from or toward each other; and a positioning mechanism provided independently of the driving device, moving the first clamping plate and the second clamping plate in synchronization, and controlling the clamping position of the split molds. In this aspect of the present invention, the positioning mechanism is provided independently of the driving device that drives the first clamping plate and the second clamping plate. Thus, the positioning mechanism can synchronously move the first clamping plate and the second clamping plate without association with the driving device and may mechanically control the clamping plates of the two split molds. The positioning mechanism may be disposed between the movable plate and the first clamping plate. The positioning mechanism may easily be disposed since such a space is relatively large. The positioning mechanism may further comprise a V-shaped link mechanism. The V-shaped link mechanism may include a connecting shaft disposed at a middle position between the movable plate and the first clamping plate; a first link arm rotatably supported by the connecting shaft and the movable plate respectively; and a second link arm rotatably supported by the connecting shaft and the first clamping plate respectively. Since the V-shaped link mechanism is sufficient to have only three rotation points, it may be of a simplified and size-reduced structure to reduce the manufacturing cost. The positioning mechanism may further comprise a guide member which guides the movement of the connecting shaft in a direction crossing an opening-and-closing direction of the split molds when the split molds open or close. The guide member may be of a simplified and size-reduced structure to reduce the manufacturing cost since it is sufficient to guide only the movement stroke of the connecting shaft. In such a manner, the mold closing position can be established by the pair of link arms and the guide member independently of the stroke of mold opening and closing. As a result, it is not necessary to adjust the positioning mechanism even in the case where the blow cavity mold is replaced by another . Therefore, the replacement of blow cavity mold may simply and easily be performed, resulting in a reduction in the operating time. The first link arm and the second link arm forming the V-shaped link mechanism may maintain the V-shape during a time between a clamping of the split molds and an opening of the split molds. In such an arrangement, the mold can smoothly be opened or closed without need of any additional force since the V- shaped link mechanism maintains its V-shape at all times. The positioning mechanism may be located between the first clamping plate and the second clamping plate. This can directly position the first clamping plate and the second clamping plate in a good manner. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view of a clamping mechanism for blow molding machine according to one embodiment of the present invention, showing it when a mold is opened; Fig. 2 is a side view of the clamping mechanism of Fig. 1, showing it when the mold is closed; and Fig. 3 is a cross - sectional view taken along a line III-III in Fig. 2 . Description of the Embodiment One embodiment of the present invention will now be described in detail with reference to the drawings. Figs. 1 to 3 show a clamping mechanism for blow molding machine according to one embodiment of the present invention. As can be seen from Figs. 1 and 2, the clamping mechanism for blow molding machine 10 comprises a first clamping plates 12, a second clamping plate 14, a movable plate 16, four tie rods 18, a clamping cylinder 20 and toggle mechanisms 22 which serve as a driving device, and a positioning mechanism 24. The first clamping plate 12 and the second clamping plate 14 are disposed facing each other. One of two split molds 28 forming a blow cavity mold 26 is mounted on the respective one of the opposing faces of the first clamping plate 12 and the second clamping plate 14. Each of the two split molds 28 includes a mounting plate 30 mounted on its backside. The split mold 28 is fixedly mounted on the first clamping plate 12 or the second clamping plate 14 through the corresponding mounting plate 30. A bottom mold (not shown) is disposed on the two split molds 28 . A bottom-mold lifting mechanism 32 raising and lowering the bottom mold is supported by a lifting mechanism support member 33 at an upper position between the first clamping plate 12 and the second clamping plate 14. The first clamping plate 12 and the second clamping plate 14 are disposed at equal distance from the center of the bottom mold. The movable plate 16 is disposed on the side of the first clamping plate 12 opposite from the side on which the second clamping plate 14 is disposed. The four tie rods 18 extend through the first clamping plate 12 and fixedly connected to the movable plate 16 and the second clamping plate 14. Thus, the first clamping plate 12 is movably supported between the movable plate 16 and the second clamping plate 14 through the tie rods 18. As shown in Fig. 3, the four tie rods 18 are arranged at positions corresponding to the four corners of the respective clamping plates 12 and 14 and the movable plate 16. Two lower tie rods 18 among the four tie rods 18 are slidably supported by support members 36 and 38 which are fixed on a machine base 34. Consequently, the movable plate 16 and the second clamping plate 14 moves together with the tie rods 18. The first clamping plate 12 is movable along the four tie rods 18 between the movable plate 16 and the second clamping plate 14. The clamping cylinder 20 is attached to one face of the movable plate 16 opposite from the other face facing the first clamping plate 12. The clamping cylinder 20 includes a cylinder rod 40 extending through the movable plate 16 toward the first clamping plate 12. The pair of toggle mechanisms 22 are disposed symmetrically in the vertical direction and between the first clamping plate 12 and the movable plate 16. Each of the toggle mechanisms 22 has a first link arm 44 rotatably mounted at one end on a cross head 42 which is attached to the end of the cylinder rod 40, a pair of second link arms 46 which are laterally located and rotatably mounted at one end on the movable plate 16 (see Fig. 3), and two pairs of third link arms 48 which are laterally located and rotatably mounted at one end on the first clamping plate 12 (see Fig. 3) . The other ends of these first, second and third link arms 44 to 48 are rotatably connected to a rotation shaft 50. In such an arrangement, when the cylinder rod 40 of the clamping cylinder 20 is extended from the mold opening position of Fig. 1, the upper toggle mechanism 22 forces the rotation shaft 50 upwardly through the first link arm 44 while the lower toggle mechanism 22 similarly forces the rotation shaft 50 downwardly. Thus, the second and the third link arms 46 and 48 will be extended to close the mold. Ultimately, as shown in Fig. 2, the second and the third link arms 46 and 48 will be positioned on a straight line to clamp the mold. When the cylinder rod 40 is retracted from the mold clamping position of Fig. 2, the procedure will be reversed to unclamp and open the mold. The positioning mechanism 24 is provided between the movable plate 16 and the first clamping plate 12 independently of the driving device including the clamping cylinder 20 and the toggle mechanisms 22. The positioning mechanism 24 moves the movable plate 16 and the first clamping plate 12 in synchronization and controls the mold clamping position of the two split molds 28. More specifically, the positioning mechanism 24 has a V-shaped link mechanism 53 and a positioning plate 58 serving as a guide member. The V-shaped link mechanism 53 comprises a pair of laterally disposed link arms 54 and 56 that connect the movable plate 16 with the first clamping plate 12 and fold at a connecting shaft 52, and the positioning plate 58 as a guide member that makes the connecting shaft 52 slidable at a predetermined position. In other words, the V-shaped linkage mechanism 53 has the connecting shaft 52 and the first link arms 54 and the second link arm 56. The opposing ends of the first link arm 54 are rotatably supported by the movable plate 16 and the connecting shaft 52, respectively. The opposing ends of the second link arm 56 are rotatably supported by the first clamping plate 12 and the connecting shaft 52, respectively. These first and second link arms 54 and 56 are maintained in their V-shaped configuration at all times. Particularly, even though the mold is clamped as shown in Fig. 1 to maximize the spacing between the movable plate 16 and the first clamping plate 12, the first link arm 54 and the second link arm 56 maintain their V-shaped configuration. When the movable plate 16 and the first clamping plate 12 are moved to open or close the mold, the connecting shaft 52 will be moved upwardly or downwardly by a predetermined distance. The connecting shaft 52 includes a roller follower 60 which is mounted thereon substantially at its central location. The positioning plate 58 is fixed on the machine base 34 and includes slide groove 62 extending in the vertical direction. The roller follower 60 slidably engages in the slide groove 62. As the roller follower 60 is moved in the slide groove 62, 52 the up-and-down movement of the connecting shaft 52/will be guided. The length of the slide groove 62 is selected to ensure 52 the desired stroke of movement in the connecting shaft 5/ The slide groove 62 includes a hardened plate 64 for preventing any wear due to the movement of the cam follower 60. Since the positioning mechanism 24 has the V-shaped linkage mechanism 53 including the link arms 54 and 56 and the connecting shaft 52, the movable plate 16 and the first clamping plate 12 are moved line-symmetrically along a vertical line passing through the connecting shaft 52. Therefore, the first clamping plate 12 and the second clamping plate 14 can be driven in synchronization and yet the mold clamping position of the two split molds 28 can be positioned. Since the positioning mechanism 24 has the positioning plate 58 for guiding the up-and-down of the connecting rod 52, the lateral movement of the connecting shaft 52 is regulated by the slide groove 62 in the positioning plate 58, even though the movable plate 16 and the first clamping plate 12 tend to do their eccentric movement at the opening or closing of the mold. Therefore, the eccentric movement in the movable plate 16 and the first clamping plate 12 can be avoided to perform the synchronized opening or closing of the mold at all times. Since the positioning plate 58 has previously been fixed at the position of the connecting shaft 52, the mold clamping position can surely be positioned when the mold is to be clamped . Since the pair of link arms 54 and 56 are sufficient to be connected only at three points and the positioning plate 58 is sufficient to have its dimensions corresponding to the stroke of vertical movement in the connecting shaft 52, the positioning mechanism 24 can be simplified and reduced in size to reduce the manufacturing cost. Moreover, the positioning mechanism 24 is provided independently of the driving device so that the pair of link arms 54 and 56 and the positioning plate 58 can only establish the mold closing position irrespectively of the stroke of mold opening or closing. As a result, it is not necessary to adjust the positioning mechanism 24 even after the blow cavity mold 26 has been replaced by another. The present invention is not limited to the aforementioned embodiment, but may be carried out in any of various modified forms without departing from the scope of the invention. Although the embodiment of the present invention has been described as to the positioning mechanism provided between the movable plate and the first clamping plate, for example, the positioning mechanism 24 may be arranged between the first clamping plate 12 and the second clamping plate 14. In such a case, the first clamping plate 12 and the second clamping plate 14 may be connected to each other through the V-shaped link mechanism 53. The connecting shaft 52 in the V-shaped link mechanism 53 may be guided in the similar manner. Thus, the first clamping plate 12 and the second clamping plate 14 can directly be positioned to provide a good positioning operation. Although the embodiment of the present invention has been described as to two clamping plates for clamping one blow cavity mold, the present invention may similarly be applied to any other case, for example, in which two blow cavity molds are to be clamped by two or more (e.g., four) clamping plates. Although the embodiment of the present invention has been described as to the driving device including the clamping cylinder and the toggle mechanisms, the present invention may use any other general driving means such as a straight hydraulic driving device, ball-screw type servo motor driving device or the like. Although the embodiment of the present invention has been described as to the roller follower rotatably moved in the slide groove of the positioning plate, it may be replaced by any other slide member. We Claim 1. A clamping device for blow molding machine, comprising: a first clamping plate (12) and second clamping plate (14) arranged facing each other; a pair of split molds (28) forming a blow cavity mold (26) being respectively mounted on facing surfaces of the first clamping plate (12) and the second clamping plate (14); a movable plate (16) disposed on a side of the first clamping plate (12) opposite from a side on which the second clamping plate (14) is disposed; a plurality of tie rods (18) extending through the first clamping plate (12) and fixedly connected to the movable plate (16) and the second clamping plate (14), and supporting the first clamping plate (12) movable between the movable plate (16) and the second clamping plate (14); and a driving device (20, 22) for driving the movable plate (16) and the first clamping plate (12) away from or toward each other; characterized in that; a positioning means (24) provided independently of the driving device, moving the first clamping plate (12) and the second clamping plate (14) in synchronization, and controlling the clamping position of the split molds (28); wherein the positioning means (24) is disposed between the movable plate (16) and the first clamping plate (12); wherein the positioning means (24) comprises a V-shaped link means (53), wherein the V-shaped link means (53) comprises: a connecting shaft (52) disposed at middle position between the movable plate (16) and the first clamping plate (12); a first link arm (54) rotatably supported by the connecting shaft (52) and the movable plate (16) respectively; and a second link arm (56) rotatably supported by the connecting shaft (52) and the first clamping plate (12) respectively; wherein the positioning means (24) comprise a guide member (58) which guides the movement of the connecting shaft (52) in a direction crossing an opening-and-closing direction of the split molds (28) when the split molds open or close. 2. The clamping device for blow molding machine as claimed in claim 1, wherein the first link arm (54) and the second link am (56) forming the V-shaped link means (53) maintain the V-shape during a time between a clamping of the split molds (28) and an opening of the split molds (28). 3. A clamping device for blow molding machine, comprising: a first clamping plate (12) and second clamping plate (14) arranged facing each other; a pair of split molds (28) forming a blow cavity mold (26) being respectively mounted on facing surfaces of the first clamping plate (12) and the second clamping plate (14); a movable plate (16) disposed on a side of the first clamping plate (12) opposite from a side on which the second clamping plate (14) is disposed; a plurality of tie rods (18) extending through the first clamping plate (12) and fixedly connected to the movable plate (16) and the second clamping plate (14), and supporting first clamping plate (12) movable between the movable plate (16) and the second clamping plate (14); and a driving device (20,22) for driving the movable plate (16) and the first clamping plate (12) away from or toward each other; characterized in that; a positioning means (24) provided independently of the driving device, moving the first clamping plate (12) and the second clamping plate (14) in synchronization, and controlling the clamping position of the split molds (28); wherein the positioning means (24) is located between the first clamping plate (12) and the second clamping plate (14); wherein the positioning means (24) comprises a V-shaped link means (53); wherein the V-shaped link means (53) comprises: a connecting shaft (52) disposed at a middle position between the first clamping plate (12) and the second clamping plate (14); a first link arm (54) rotatably supported by the connecting shaft (52) and the first clamping plate (12) respectively; and a second link arm (56) rotatably supported by the connecting shaft (52) and the second clamping plate (14) respectively; wherein the positioning means (24) comprise a guide member (58) which guides the movement of the connecting shaft (52) in a direction crossing an opening-and-closing direction of the split molds (28) when the split molds (28) open or close. 4. The clamping device for blow molding machine as claimed in claim 3, wherein the first link arm (54) and the second link arm (56) forming the V-shaped link means (53) maintain the V-shape during a time between a clamping of the split molds (28) and an opening of the split molds (28). A clamping device for blow molding machine, comprising: a first clamping plate (12) and second clamping plate (14) arranged facing each other; a pair of split molds (28) forming a blow cavity mold (26) being respectively mounted on facing surfaces of the first clamping plate (12) and the second clamping plate (14); a movable plate (16) disposed on a side of the first clamping plate (12) opposite from a side on which the second clamping plate (14) is disposed; a plurality of tie rods (18) extending through the first clamping plate (12) and fixedly connected to the movable plate (16) and the second clamping plate (14), and supporting the first clamping plate (12) movable between the movable plate (16) and the second clamping plate (14); and a driving device (20, 22) for driving the movable plate (16) and the first clamping plate (12) away from or toward each other; a positioning means (24) provided independently of the driving device, moving the first clamping plate (12) and the second clamping plate (14) in synchronization, and controlling the clamping position of the split molds (28); wherein the positioning means (24) is disposed between the movable plate (16) and the first clamping plate (12); wherein the positioning means (24) comprises a V-shaped link means (53), wherein the V-shaped link means (53) comprises: a connecting shaft (52) disposed at middle position between the movable plate (16) and the first clamping plate (12); a first link arm (54) rotatably supported by the connecting shaft (52) and the movable plate (16) respectively; and a second link arm (56) rotatably supported by the connecting shaft (52) and the first clamping plate (12) respectively; wherein the positioning means (24) comprise a guide member (58) which guides the movement of the connecting shaft (52) in a direction crossing an opening-and- closing direction of the split molds (28) when the split molds open or close.

Documents:

00234-cal-2001-abstract.pdf

00234-cal-2001-assignment.pdf

00234-cal-2001-claims.pdf

00234-cal-2001-correspondence.pdf

00234-cal-2001-description (complete).pdf

00234-cal-2001-drawings.pdf

00234-cal-2001-form 1.pdf

00234-cal-2001-form 18.pdf

00234-cal-2001-form 2.pdf

00234-cal-2001-form 3.pdf

00234-cal-2001-form 5.pdf

00234-cal-2001-letter patent.pdf

234-CAL-2001-FORM-27.pdf