Mold clamping device and injection molding machine

A mold clamping device includes a fixed platen on which a fixed mold is disposed, a movable platen on which a movable mold that defines a cavity along with the fixed mold is disposed, a tie bar configured to resist a mold clamping force that is generated between the fixed platen and the movable platen, and a half nut opening and closing device configured to grip the tie bar, thereby locking the movable platen and the tie bar, in which the half nut opening and closing device includes half nuts configured to grip the tie bars, an actuator which is disposed on the movable platen and configured to move the half nuts back and forth with respect to the tie bars, and a clevis configured to connect the actuator to the half nuts so as to allow the actuator to swing with respect to the gripping member.

TECHNICAL FIELD

The present invention relates to a mold clamping device of an injection molding machine or a die cast molding machine, which is provided with a fixed platen, a movable platen, a tie bar connecting the movable platen and the fixed platen, and a mold clamping and retaining device retaining a mold clamping force by gripping the tie bar, and an injection molding machine.

BACKGROUND ART

As is well known, in molding machines such as an injection molding machine, there is a molding machine having a configuration in which a mold clamping force during molding (for example, injection molding) generated between a fixed platen on which a fixed mold is disposed and a movable platen on which a movable mold is disposed is retained by a tensile force of a tie bar.

In the molding machine having such a configuration, a mold clamping device having a configuration in which when the movable platen and the fixed platen are in a mold clamping state, a locking-shaped portion formed in the tie bar is gripped by a half nut or the like, thereby making the movable platen be retained on the fixed platen, is widely known (refer to, for example, PTL 1).

Further, in the molding machine having such a configuration, there is also a method of performing mold opening (hereinafter, referred to as mold release) by moving the tie bar in a direction in which the movable platen is opened, by driving the movable platen through the half nut by the tie bar in a state where the locking-shaped portion formed in the tie bar remains gripped by the half nut or the like, because a large mold opening force is required at the time of a mold opening operation to separate the fixed mold and the movable mold from a mold clamping state when extracting a molded article after resin is filled into a mold.

In this manner, in the mold clamping device to grip the tie bar by the half nut or the like, for example, as shown inFIG. 14, a connection mechanism123is used in which a flange124provided at a half nut121is pressed by a knuckle125of a tip portion of a rod122of an actuator (for example, a hydraulic cylinder), thereby fixing the actuator to the half nut. In this case, in order to fix the rod122to the half nut121without rattle, usually, connection is performed by the knuckle125and the flange124with a clearance126provided.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Problem to be Solved by the Invention

However, if a molding machine having such a configuration is operated for a long period of time, there is a case where fatigue breaking due to bending occurs in the rod122fixed to the half nut121. Therefore, there is a strong demand for a technique capable of preventing the occurrence of bending damage of the rod of the actuator even if the molding machine is operated for a long period of time.

Therefore, the inventors of the present invention have extensively studied the cause of bending damage of a rod, with a hydraulic cylinder as an example, and as a result, have obtained the following knowledge.

First, in the half nut121configuring the mold clamping device, in a state where the half nut121is simply closed, as shown inFIG. 15, an axis line of the tie bar115and an axis line of the half nut121are parallel, as shown by a solid line. However, at the time of mold release, a force in a direction of an arrow P acts on the half nut121, whereby the half nut121is separated from the tie bar on the side away from the fixed platen, and thus the angle between the two axis lines is occurred as shown by a two-dot chain line.

Further, although not shown in the drawing, at the time of mold clamping, four corners of the movable platen are pulled to the fixed platen side by the tie bar, whereby deflection in which a central portion of the surface on the side opposite to the fixed platen of the movable platen becomes convex is generated, and due to this deflection, the half nut which is in close contact with the movable platen is also inclined with respect to the actuator fixed to a central portion between two tie bars and provided at a position where deformation of the movable platen is small.

As a result, as shown inFIG. 16, a bending force is generated in a tip portion of the rod122fixed to the side surface of the half nut121, thereby causing bending damage of the rod122.

The present invention has been made in consideration of such knowledge and has an object to provide a mold clamping device which is provided with a movable platen, a tie bar connecting the movable platen and a fixed platen, and a mold clamping and retaining device transmitting and retaining a mold clamping force by gripping the tie bar and can prevent the occurrence of bending damage of a rod of an actuator even if a half nut is inclined with respect to the actuator at the time of molding, and particularly an injection molding machine.

Means for Solving the Problem

In order to solve the above-described problem, the present invention proposes the following means.

(1) According to an aspect of the present invention, there is provided a mold clamping device including: a fixed platen on which a fixed mold is disposed; a movable platen on which a movable mold that defines a cavity along with the fixed mold is disposed and which is allowed to move with respect to the fixed platen; a tie bar configured to resist a mold clamping force that is generated between the fixed platen and the movable platen; and a mold clamping and retaining device which configured to grip the tie bar, thereby locking the movable platen and the tie bar, in which the mold clamping and retaining device includes a gripping member configured to grip the tie bar, an actuator which is disposed on the movable platen or the fixed platen and configured to move the gripping member back and forth with respect to the tie bar, and a swinging member which is configured to connect the actuator and the gripping member so as to allow the actuator to swing with respect to the gripping member.

According to the mold clamping device related to the aspect of the present invention of the above (1), since the actuator and the gripping member are connected so that they can swing by the swinging member, the angle with respect to the actuator generated in the gripping member at the time of molding is cancelled. As a result, it is possible to prevent the occurrence of bending in a rod of the actuator due to the inclination of the gripping member. As a result, it is possible to prevent the occurrence of bending damage of the rod of the actuator.

(2) In the mold clamping device according to the above (1), the gripping member may include two sets of half nuts which are disposed corresponding to two tie bars and which can come into contact with and be separated from the respective tie bars and in each of which a second locking-shaped portion that meshes with a first locking-shaped portion formed in the tie bar is formed, and first and second gripping members each configured to connect half nut pieces in which the second locking-shaped portions respond to a movement in the same direction, among the two sets of half nuts, by a connection member, and the first gripping member and the second gripping member may be configured so as to grip the two tie bars in cooperation with each other.

According to the mold clamping device related to the aspect of the present invention of the above (2), two half nut pieces configuring the first gripping member and two half nut pieces configuring the second gripping member have rigidity of a connection structure. Further, since the half nut pieces configuring the first and second gripping members are connected by the connection member, thereby interfering with each other's angle, the occurrence of an angle between the two half nut pieces is prevented. As a result, it is possible to prevent the occurrence of bending damage of the rod of the actuator.

Further, the half nuts come into contact with and are separated from the respective tie bars in synchronization. As a result, in addition, since the first gripping members and the second gripping members simultaneously operate in synchronization, the occurrence of movement variation for each half nut is prevented, and thus the time required to complete the contact and separation of the half nut can be shortened and productivity can be improved.

Further, in a case where the first gripping member and the second gripping member are synchronized by a link or the like, since all the half nut pieces of the first gripping member and the second gripping member simultaneously operate in synchronization, movement variation for each half nut piece is eliminated, and thus the time required to complete the contact and separation of the half nut piece can be further shortened and productivity can be improved.

In this specification, the half nut also includes a half nut in which a circumferential convex portion protrudes radially inward of a hole without having a lead configuring a screw in the hole, in addition to a half nut in which a female screw is formed in a hole formed in a casing.

(3) In the mold clamping device according to the above (2), each of the first gripping member and the second gripping member may have two sets of connection members, and the connection members of the first gripping member and the connection members of the second gripping member may be disposed diagonally in a view of the connection member in an axial direction of the connection member.

According to the mold clamping device related to the aspect of the present invention of the above (3), since the connection members of the first gripping member and the connection members of the second gripping member are disposed diagonally, the occurrence of an angle of the respective half nut pieces with respect to the tie bar during contact and separation movement and at the time of completion of the movement is prevented.

As a result, it is possible to more stably prevent the occurrence of bending damage of the rod of the actuator.

(4) In the mold clamping device according to the above (2) or (3), the connection member may be a connecting rod.

According to the mold clamping device related to the aspect of the present invention of the above (4), it is possible to easily increase the bending rigidity of a connection structure which has a simple shape. As a result, it is possible to more stably prevent the occurrence of bending damage of the rod of the actuator.

(5) According to another aspect of the present invention, there is provided an injection molding machine including the mold clamping device according to any one of the above (1) to (4).

According to the injection molding machine related to the aspect of the present invention of the above (5), it is possible to prevent the occurrence of bending in the rod of the actuator due to inclination of the gripping member. As a result, it is possible to prevent the occurrence of bending damage of the rod of the actuator.

Effects of the Invention

According to the mold clamping device and the injection molding machine related to the present invention, since the actuator and the gripping member are connected so that the actuator is allowed to swing with respect to the gripping member, even in a case where inclination with respect to the actuator occurs in the gripping member, it is possible to prevent the occurrence of bending of the rod of the actuator. As a result, it is possible to prevent the occurrence of bending damage of the rod of the actuator.

DESCRIPTION OF EMBODIMENTS

FIGS. 1 and 2are diagrams showing a mold clamping device which is used in, for example, an injection molding machine according to the first embodiment, and reference numeral1denotes the mold clamping device. Further,FIGS. 3 to 7are diagrams describing a half nut opening and closing device (a mold clamping and retaining device)20.

The mold clamping device1is provided with a base10of a molding machine main body, a fixed platen11, a movable platen12, a tie bar15, a movable platen moving means17, and the half nut opening and closing device20.

As shown inFIGS. 1 and 2, the fixed platen11is provided on one end side of the base10, and the movable platen12is disposed so as to be able to slide with respect to the base10and to face the fixed platen11.

A fixed mold13can be mounted on the fixed platen11, a movable mold14can be mounted on the movable platen12, and the fixed mold13and the movable mold14are made so as to define a cavity.

The fixed platen11and the movable platen12are connected by four tie bars15adjacent to each other in a horizontal direction and a vertical direction.

The four tie bars15are disposed to pass through the movable platen12, and the movable platen12is made so as to be able to slide on the tie bars15.

In the tie bar15, a piston for mold clamping force generation16is provided on the fixed platen11side and a circumferential groove portion (a first locking-shaped portion)15ais formed at an end portion on the side opposite to the fixed platen11.

Further, the movable platen moving means17which is electrically powered, for example, is provided on the base10, thereby being able to move the movable platen12with respect to the fixed platen11. In this case, the movable platen moving means17may be a hydraulic cylinder.FIG. 1shows a mold closing state where the movable mold14is brought into contact with the fixed mold13by moving the movable platen12in a direction of the fixed platen11by the movable platen moving means17.

The half nut opening and closing device20is provided with a half nut21, a half nut22, a guide box23, a link plate25, and a connecting rod26and is provided in two upper and lower stages to correspond to two tie bars15and15on the upper side and two tie bars15and15on the lower side among the four tie bars15, on the surface opposite to the movable mold14of the movable platen12.

The half nut21is provided with a half nut piece21aand a half nut piece21band is made so as to grip the tie bar15by making circumferential convex portions (second locking-shaped portions), which are formed in the half nut piece21aand the half nut piece21band protrude radially inward, mesh with the circumferential groove15aof the tie bar15.

Further, the half nut22is provided with a half nut piece22aand a half nut piece22band is made so as to grip the tie bar15by making circumferential convex portions (second locking-shaped portions), which are formed in the half nut piece22aand the half nut piece22band protrude radially inward, mesh with the circumferential groove15aof the tie bar15.

The half nut pieces21aand21band the half nut pieces22aand22bare respectively disposed so as to be able to slide in the horizontal direction (the right-left direction inFIG. 2), in the guide boxes23provided on the movable platen12, are respectively connected through the link plates25each supported on the outside (the upper and lower surfaces) of the guide box23, and are respectively made so as to rotate around fulcrum pins24protruding upward and downward at the center position of the tie bar15.

As a result, the half nut pieces21aand21band the half nut pieces22aand22bare made such that the movement thereof back and forth with respect to the tie bar15synchronizes.

Pins21care respectively provided to protrude upward and downward on the upper and lower surfaces of the half nut pieces21aand21b, as shown inFIGS. 4 and 5.

Further, pins22care respectively provided to protrude upward and downward on the upper and lower surfaces of the half nut pieces22aand22b.

In the link plate25, a round hole25ais formed at the center and two long holes25bare formed at both end portions which are symmetrical with respect to the round hole25a, and the fulcrum pin24protruding outward from the guide box23is inserted into the round hole25a. In addition, in the drawings, the long hole25bis shown in a rectilinear long hole shape. However, in consideration of the movement profile of the fulcrum pin24, a long hole having a curved shape such as a bent shape is also acceptable.

Further, the upper and lower pins21cof the half nut pieces21aand21band the upper and lower pins22cof the half nut pieces22aand22bare respectively inserted into the long holes25bof both end portions. In addition, in the drawings, an example in which the link plate25is provided outside of the guide box23is shown. However, a configuration is also acceptable in which the link plate25is provided between the guide box23and the half nut.

The connecting rod26includes two first connecting rods26aand two second connecting rods26band is disposed such that the first connecting rods26aslidably pass through the half nut piece21band connect the half nut piece21aand the half nut piece22aand the second connecting rods26bslidably pass through the half nut piece22aand connect the half nut piece21band the half nut piece22b.

In addition, the half nut piece21a, the half nut piece22a, and the two first connecting rods26aconnecting the half nut piece21aand the half nut piece22aconfigure a first gripping member28awhich operates the half nut piece21aand the half nut piece22ain synchronization with each other.

Further, the half nut piece21b, the half nut piece22b, and the two first connecting rods26bconnecting the half nut piece21band the half nut piece22bconfigure a second gripping member28bwhich operates the half nut piece21band the half nut piece22bin synchronization with each other.

Further, a bracket27is provided on the connecting rod26between the half nut piece21band the half nut piece22a, and a hydraulic cylinder (an actuator)30is mounted on the bracket27. Further, the bracket27is fixed to the two first connecting rods26a.

In the hydraulic cylinder30, a rod31is connected to the half nut piece21bthrough a clevis32having a rotation axis in the vertical direction, and thus, even in a case where an angle occurs in the half nut piece21b, the angle is cancelled by the rotation of the clevis32, whereby the occurrence of a bending force of the rod31is prevented.

Next, an operation of the half nut opening and closing device20will be described with reference toFIGS. 4 and 5.

FIG. 4shows a front view in a state where the half nut opening and closing device20is opened and plan views of the half nuts21and22, andFIG. 5shows a front view in a state where the half nut opening and closing device20is closed and plan views of the half nuts21.

First, when a mold is closed by the movable platen moving means17, as shown inFIG. 4, the circumferential groove portions15aof the tie bars15are disposed between the opened half nut21(half nut pieces21aand21b) and between the opened half nut22(half nut pieces22aand22b).

Next, when the rod31of the hydraulic cylinder30moves forth, the half nut piece21bof the first gripping member28amoves to the left side in the drawing, and due to a reaction force, the half nut piece21amoves to the right side in the drawing through the bracket27to which the hydraulic cylinder30is fixed and the two first connecting rods26a. At this time, since the half nut piece22aand the half nut piece21aare connected by the two first connecting rods26aand the half nut piece22band the half nut piece21bare connected by the two second connecting rods26b, the half nut pieces22aand22brespectively move in the same direction as the half nut pieces21aand21b, thereby coming close to the tie bars15and15.

At this time, as shown inFIG. 4, each of the link plates25connected to the half nuts21and22rotates in a direction of an arrow R around the fulcrum pin24, and thus the half nut pieces21aand22asimultaneously come close to the tie bars15in synchronization with the half nut pieces21band22b.

Subsequently, the half nut pieces21aand21band the half nut pieces21aand21brespectively come close to the tie bars15in synchronization, whereby the half nuts21and22mesh with the circumferential groove portions15aof the tie bars15, thereby gripping the tie bars15.

According to the half nut opening and closing device20related to the first embodiment, the hydraulic cylinder30and the half nut21are connected through the clevis32, and thus the hydraulic cylinder30is made so as to be able to swing with respect to the half nut21. As a result, even if the half nut piece21b(the half nut21) is inclined with respect to a direction in which the tie bar15extends, the angle between the half nut piece21band the direction is cancelled by its rotation around the axis of the clevis pin32, whereby the action of a bending force on the rod31of the hydraulic cylinder30is prevented, and thus the occurrence of bending damage of the rod31of the hydraulic cylinder30is prevented.

In addition, a synchronization mechanism of the half nut by the link plate25and the support pin24can also be omitted for the purpose of cost reduction or the like. However, by synchronizing the half nuts21aand21band the half nuts22aand22bby the respective link plates25, it is possible to enable more reliable synchronization than in a case where only the first and second connecting rods26aand26bare provided.

Further, in this embodiment, a case is shown in which each of the rod members26aand26bis used as a connection member connecting the half nut pieces which move in the same direction. However, a configuration is also acceptable in which the half nut piece21aand the half nut piece22bmoving toward the center of two tie bars and the half nut piece21band the half nut piece22amoving outward from the center of two tie bars are respectively connected by, for example, link structures, whereby the half nuts21and22grip the tie bars. In addition, a configuration may also be made such that the half nut pieces moving toward the center of two tie bars and the half nut pieces moving outward from the center of two tie bars respectively move in synchronization by connection members, links, or other means.

Next, a mold clamping device according to a second embodiment of the present invention will be described with reference toFIG. 8.

FIG. 8is a diagram when a connector33connecting the rod31of the actuator and the half nut piece21bis viewed in a plane.

The second embodiment is different from the first embodiment in that, instead of the clevis32, the connector33provided with a flange33A and a knuckle33B which is disposed in the flange33A is used, and others have the same configurations as those of the half nut opening and closing device20according to the first embodiment.

In the connector33, clearances G and H are set between the flange33A and the knuckle33B on both sides in the extension direction of the tie bar15and in the movement direction of the rod31. As a result, the flange33A is rotatable in a direction of an arrow R1, and thus, even if inclination occurs in the half nut piece21b, the inclination is absorbed by the clearances G and H, whereby action of a bending force from the flange33A to the rod31is suppressed.

In addition, if a chamfered portion33C as shown inFIG. 8or a corner R is provided on the tip side of the knuckle33B, since rotation at a tip corner portion of the knuckle33B is smoothly performed, the contact thereof with the flange33A is further relieved, and thus it is more suitable.

Next, a mold clamping device according to a third embodiment of the present invention will be described with reference toFIG. 9.

The third embodiment is different from the first embodiment in that, instead of the clevis32, a spherical joint34is used, and others have the same configurations as those of the first embodiment.

The spherical joint34is provided with a flange34A and a knuckle34B connected to the rod31, as shown inFIG. 9, and a concave portion34C which is formed of a portion of a spherical surface is formed inward at the flange34A. The knuckle34B has a portion of a spherical surface having a sphere radius equal to the sphere radius of the concave portion34C or slightly smaller than the radius of the concave portion34C so as to be able to slide in the concave portion34C, and thus the knuckle34B is inserted into the concave portion34C, whereby the knuckle34B can rotate with respect to the flange34A without selecting a direction within a predetermined range.

As a result, even if the half nut piece21bis inclined due to a complex movement, the inclination angle of the half nut piece21bis cancelled by its rotation at the spherical joint34, whereby the occurrence of a bending force in the rod31is prevented.

Next, a mold clamping device according to a fourth embodiment of the present invention will be described with reference toFIG. 10.

The fourth embodiment is different from the first embodiment in that, instead of the clevis32, a universal joint35is used, and others have the same configurations as those of the first embodiment.

The universal joint35is provided with a first flange35A, a second flange35B connected to the rod31, and a connection member35C connecting the first flange35A and the second flange35B, as shown inFIG. 10, and the first flange35A and the connection member35C are made so as to be able to rotate around an axis O1 and the second flange35B and the connection member35C are made so as to be able to rotate around an axis O2.

As a result, even if the half nut piece21bis inclined through a complex movement, the angle of the half nut piece21bis cancelled by its rotation at the connection member35C, whereby the occurrence of a bending force of the rod31is prevented.

Next, a mold clamping device according to a fifth embodiment of the present invention will be described with reference toFIGS. 11A and 11B.

The fifth embodiment is different from the first embodiment in that, in addition to the clevis32, a spherical bush40is used, and others have the same configurations as those of the first embodiment.

The spherical bush40is provided with an outer peripheral spherical member40ainside of which a portion of a spherical surface is formed at an outer periphery thereof and a shaft portion32J of the clevis32is fitted in a hole40b, and a concave member40cwhich is connected to the rod31and inside of which a portion of a spherical surface having a sphere radius equal to the sphere radius of the outer peripheral spherical member40aor slightly larger than the outer peripheral spherical member40aso as to be able to slide on the spherical portion40ais formed. As shown inFIG. 11A, since the shaft portion32J of the clevis32is fitted in the hole40bof the spherical bush40and the outer peripheral spherical member40ais inserted into the concave member40c, the concave member40ccan rotate with respect to the outer peripheral spherical member40awithout selecting a direction within a predetermined range.

As a result, even if the half nut piece21bis inclined due to a complex movement, the inclination is absorbed by rotation at the spherical bush40, whereby the occurrence of a bending force in the rod31is prevented.

Further, as shown inFIG. 11B, elastic bodies41aand41bsuch as disc springs may be provided on the top and bottom of the spherical bush40. Further, instead of the disc springs41aand41bshown inFIG. 11B, other spring members such as a coil spring, a lead spring, an air spring, or a liquid spring may be used. Further, the elastic body may be provided at any one of the top and the bottom, rather than both the top and the bottom. In this case, even in a case where inclination occurs in the half nut21b, whereby the shaft portion32J of the clevis32is deviated from the designed center position which is a functionally most preferable position, a reaction force to return the shaft portion32J of the clevis32to the designed center position can be applied by the elastic bodies41aand41b.

Next, a half nut opening and closing device20A according to a sixth embodiment of the present invention will be described with reference toFIG. 12.

The sixth embodiment is different from the first embodiment in that, instead of the bracket27connecting the hydraulic cylinder30and the two first connecting rods26a, a bracket27A is used and the bracket27A is made so as to be able to rotatably support a support pin30A protruding from the hydraulic cylinder30in the vicinity of the longitudinal center of the hydraulic cylinder30, and others have the same configurations as those of the first embodiment.

According to the half nut opening and closing device20A, since the hydraulic cylinder30is connected to the half nut piece21bthrough the clevis32at the tip of the rod31and the hydraulic cylinder30itself is made so as to be able to rotate at the center in a longitudinal direction, even if large inclination occurs in the half nut piece21b, the angle of the half nut piece21bis cancelled by its rotation at the support pin30A, whereby the occurrence of a bending force in the rod31is prevented. In addition, it is preferable that both the devises32and30A be provided. However, the hydraulic cylinder30may be supported so as to swing by only the clevis30A with the clevis32omitted.

Next, a half nut opening and closing device20B according to a seventh embodiment of the present invention will be described with reference toFIG. 13.

The seventh embodiment is different from the first embodiment in that, instead of the bracket27connecting the hydraulic cylinder30and the two first connecting rods26a, a bracket27B is used and the bracket27B rotatably supports a rear end portion of the hydraulic cylinder30through a clevis32A, and others have the same configurations as those of the first embodiment.

According to the half nut opening and closing device20B, even if large inclination occurs in the half nut piece21b, the angle of the half nut piece is cancelled by its rotations at the devises32and32A, whereby the occurrence of a bending force in the rod31is prevented. In addition, it is preferable that both the clevis32and the clevis32A be provided. However, the hydraulic cylinder30may be supported so as to swing by only the clevis32A with the clevis32omitted.

The preferred first to third embodiments of the present invention have been described above. However, the present invention is not limited to such examples. It will be apparent to those skilled in the art that various change examples or modification examples can be contemplated within the scope of the technical idea stated in the appended claims, and it is to be understood that these examples naturally also belong to the technical scope of the present invention.

For example, in the embodiments described above, a case where the actuator is the hydraulic cylinder30has been described. However, in place of the hydraulic cylinder, a variety of actuators including, for example, an air cylinder and a ball screw type electrically-powered or hydraulically-powered motor may be used.

Further, in the embodiments described above, a case has been described in which the mold clamping device1is provided with the four tie bars and the four half nut opening and closing devices20,20A, or20B and is used in an injection molding machine. However, the mold clamping device1may be applied to a die cast molding machine instead of the injection molding machine. Further, the present invention may be applied to a mold clamping device having a configuration in which a connecting rod (a connection member) connects three or more half nuts and provided with tie bars exceeding four.

Further, in the embodiments described above, a case has been described in which the hydraulic cylinder30and the half nut21are made so as to be able to swing by the clevis32, the connector33, the spherical joint34, the universal joint35, the clevis32and the spherical bush40, the clevis32and the bracket27A, or the clevis32and the bracket27B. However, other swinging members may be used. Further, in the sixth and seventh embodiments, a configuration in which the rod31of the hydraulic cylinder30and the half nut piece21bare connected by the clevis32is adopted. However, a configuration in which the clevis32is not provided is also acceptable.

Further, in the embodiments described above, a case has been described in which the half nut pieces21aand22aand the half nut pieces21band22bare respectively connected by the link plates25and the operations of the first gripping member28aand the second gripping member28bsynchronize. However, it is possible to arbitrarily set whether to use the link plate25. For example, a configuration is also acceptable in which the first gripping member28ais driven by the hydraulic cylinder30and the second gripping member28bis driven by an actuator other than the hydraulic cylinder30. Further, synchronization control of the movement of each of the first gripping member28aand the second gripping member28bmay be performed by electric control instead of the link plate25.

Further, a case where the hydraulic cylinder30is fixed to the first connecting rods26ahas been described. However, the hydraulic cylinder30may be mounted on a fixed member such as the guide box23which does not move even if the movable platen12or the half nut21amoves, or a member such as the half nut22acapable of supporting the movement reaction force of the half nut21a.

Further, the tie bar15may be gripped by using a member capable of being divided into three or more, instead of the half nut21or22.

Further, a member which is mounted on the clevis32is set to be the rod31. However, if room is present in a space around the clevis32, a configuration may be adopted in which, rather than the rod31being supported on the clevis32, a clevis support structure (not shown) is provided at a main body end surface portion of the hydraulic cylinder30, thereby supporting the clevis32, and the rod31is connected to the bracket27.

Further, in the embodiments described above, a case has been described in which the first gripping member28aand the second gripping member28brespectively have the two connecting rods26aand the two connecting rods26band the connecting rods26aof the first gripping member28aand the connecting rods26bof the second gripping member28bare disposed diagonally in a view of an axis line direction of the connecting rod26. However, the number of connecting rods26, the configuration thereof, and whether or not to adopt diagonal disposition can be arbitrarily set.

Further, in the embodiments described above, a case where the first gripping member28aand the second gripping member28bare disposed in the horizontal direction has been described. However, the first gripping member28aand the second gripping member28bmay be disposed in the vertical direction.

Further, in the embodiments described above, a case has been described in which the tie bar15is disposed at the fixed platen11and the movable platen12moves with respect to the tie bar15. However, the present invention may be applied to, for example, a molding machine made such that the tie bar15is allowed to move with respect to the fixed platen11. In this case, the present invention is provided to the fixed platen11.

INDUSTRIAL APPLICABILITY

According to the mold clamping and retaining device related to the present invention, since the half nut and the actuator are connected so that the actuator is allowed to swing with respect to the gripping member, whereby it is possible to prevent bending damage of the rod, the mold clamping and retaining device is industrially applicable.

REFERENCE SIGNS LIST