JP2006281493A - Mold clamping device of injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To omit the use of a locking adhesive by fixing the link pin of the mold clamping device of an injection molding machine by a set screw composed of two members, that is, a fixing screw member and a press screw member and to solve the subject due to an adhesive used at the time of attachment and detachment of the set screw. <P>SOLUTION: In the mold clamping device of the injection molding machine, the set screw 26 of the link pin 16 is constituted of two members, that is, the fixing screw member 27 and the press screw member 28 both of which have screws same in outer diameter and pitch provided on their outer peripheral surfaces. A tapered recessed place 27a and a tapered protruded part 27b, both of which are fitted to each other, are respectively provided to the upper surface of the fixing screw member 27 and the undersurface of the press screw member 28 and either one of them is provided at an eccentric position. The fixing screw member 27 is laterally pressed by the fitting and eccentricity of the recessed place 17a and the protruded part 27b and the clamping force of the press screw member 28 to fix the link pin 16 to a link 17. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mold clamping device of an injection molding machine that performs forward / backward movement and mold clamping of a movable platen by bending and stretching of a link mechanism.

  As a link mechanism employed in a mold clamping device of an injection molding machine, a toggle link mechanism that bends and stretches by a toggle and a mechanism that flexes and stretches a link by a crank are known. In any of them, the link is connected to the pin receiving portion of the pressure receiving plate and the movable plate connected by the diver by a link pin so as to be able to bend and extend, and the link is extended by a toggle or a crank to generate an extension of the tie bar. The mold is shrunk by the elastic recovery force.

  The toggle link mechanism includes a first link and a second link connected by link pins, a crosshead on the pressure receiving plate side driven by hydraulic pressure or electricity, and an operation link provided across the crosshead and the first link. There are a single toggle mechanism and a double toggle mechanism.

  The generation of the clamping force by the toggle link mechanism adopted by the clamping device is due to the elastic force of the tie bar that is generated when the link is fully extended, and both the link extension force and the elastic force of the tie bar act on each link pin. To do. Therefore, if the position of the link pin is in a state where it slightly changes with the operation of the link, the enlargement ratio and the moving speed acting on the toggle mechanism also change, and this is caused between the fixed platen and the movable platen. Since it will affect the parallelism, straightness, operability, etc., both ends of the link pin are fixed to the link or the pin receiving part with a set screw, and the link pin rotates as the link bends and stretches. In this way, the design accuracy is maintained for a long period of operation.

  FIG. 7 illustrates a conventional set screw used for fixing a link pin. The set screw 1 is formed by integrally forming a convex portion 1a on a lower surface of a screw shaft that is screwed into a screw hole 2a formed in an end portion of a link 2. The convex portion 1a is formed in a conical shape in which an opening drilled in an end portion of the link pin 3 is fitted with a perforated hole 3a having a tapered surface. The end of the link pin 3 is fixed to the link 2 by being screwed into the link 2. In order to prevent the set screw 1 from loosening, an adhesive is applied as a screw lock agent, and the screw screw gap is filled with the adhesive to lock the set screw 1 to the link 2.

In addition, as a screw member that fixes a rotating member such as a flywheel to the shaft, two members, a fixed screw member and a presser screw member, are adopted, and an eccentric part is provided on the presser screw member to prevent the fixing screw member from loosening. Things are known.
JP 2004-025813 A Japanese Patent Laid-Open No. 8-281175 JP 2001-50292 A

The fixing of the link pin by the conventional set screw has the following problems.
(1) The pressing force of the convex part on the perforation is inconsistent due to the variation in the thickness of the adhesive applied and the variation in the tightening force of the set screw caused by tapping and the material applied to the link pin or link. It tends to be sufficient, and the convex part is damaged by the stress concentrated on the link pin, and the fixing function is easily lost.
(2) Since the adhesive is applied to the set screw, it is difficult to screw it in, and it takes time to completely screw in and fix it, so that the work efficiency is lowered. If applied, the effect of the adhesive will decrease,
(3) Since the adhesive is applied, it is not easy to unscrew the set screw during maintenance, and it takes time to remove the link pin.
(4) The set screw lock adhesive removed by maintenance cannot be used repeatedly because the effect of preventing loosening of reuse is reduced due to damage caused by attachment and detachment.

  The present invention was conceived in order to solve the problem of the link pin by the conventional set screw, and its purpose is composed of two members, a fixing screw member and a presser screw member. The screw member provided with the eccentric part is used for the set screw that fixes the link pin, and the application of the locking adhesive, which has been indispensable in the past, can be omitted, and the link pin can be fixed only by the set screw. An object of the present invention is to provide a mold clamping device for an injection molding machine.

  The present invention also provides a mold clamping device for an injection molding machine in which the lower surface of the fixing screw member is formed so as to be screwed, fitted, or abutted with the side surface of the link pin, and thereby the link pin is fixed without loosening. There is to do.

  According to the present invention, the first link and the second link are connected to the pin receiving portions of the pressure receiving plate and the movable plate by link pins so that they can be bent and extended. In a mold clamping device of a molding machine having a link mechanism fixed to each part, when the link and the link pin are fixed by a set screw, the set screw has a screw having the same outer diameter and the same pitch on the outer peripheral surface. And a fixing screw member. The fixing screw member and the holding screw member have a recess or a convex portion on which the tool can be fitted on the upper surface, and the holding screw. The member has a concave or convex portion on the lower surface that fits with a convex or concave portion on the upper surface of the fixing screw member, and the convex or concave portion on the lower surface of the pressing screw member and the concave portion on the upper surface of the fixing screw member. Place or convex part fits each other A fixed screw which is firstly screwed into the screw hole of the link or the pin receiving part by the eccentricity and mutual fitting. The member is pressed to the side by the clamping force of the presser screw member, and the link pin is fixed.

  The link pin has a hole having a smaller diameter than the screw hole on a side surface facing the screw hole of the link or the pin receiving portion, and a convex portion of a small diameter shaft that fits the hole is formed on a lower surface of the fixed screw member. It is said to project in one piece.

  The link pin has a perforation at a portion facing the screw hole of the link or the pin receiving portion, and a conical convex portion that fits into the perforation is integrally projected on the lower surface of the fixed screw member. It will be.

  The link pin has a flat contact surface on the side facing the screw hole of the link or the pin receiving portion, and the lower surface of the fixed screw member is formed on a flat surface similar to the contact surface. That's it.

  In the above configuration, since the concave and convex portions on the upper surface and the lower surface of the fixing screw member and the presser screw member are located eccentrically from the center of the screw shaft within a range in which they can be fitted to each other in the screw hole of the link. As the screw is screwed in, the eccentricity generated there and the mutual fitting causes the fixing screw member tightening the link pin to be strongly pressed to the side, and this state is maintained even after the link pin is fixed. The screw member is not loosened, and the fixing of the link pin by the screw member can be maintained for a long time.

  Also, since it is not necessary to apply a locking agent to the fixing screw member, the set screw can be screwed in and loosened smoothly, and the link pin is fixed by the fixing screw member and then the presser screw member is screwed in. Since the fixing screw member is tightened, the link pin can be reliably fixed by the fixing screw member.

  Also, the link pin can be fixed with a set screw by fitting the convex portion of the small-diameter shaft projecting on the lower surface of the fixing screw shaft with the perforation provided on the link pin, or the perforation of the link pin and the lower surface of the fixing screw shaft. This can be done by contact with the flat part of the fixed screw shaft and the flat side surface of the link pin, etc., and can be fixed by screwing, fitting, contact, etc. Because it can be tightened and fixed by screwing in with the specified torque, fixing with excessive tightening torque is not performed, and even if the load and stress received by the link pin concentrate on the fixed part, the fixed part will not be damaged, It will stay fixed for a long time.

  FIG. 1 and FIG. 2 show a mold clamping device of an injection molding machine that opens and closes a mold and mold-clamps by a normal double link toggle mechanism having a pair of upper and lower link mechanisms. In this mold clamping device, a pressure receiving plate 11 and a fixed platen 12 are connected to a machine base 10 by connecting tie bars 13 and 13 at four corners, a movable plate 14 inserted through the tie bars 13 and 13, and a pressure receiving plate. 11 and a double link toggle mechanism 15 provided over the area 11.

  The double link toggle mechanism 15 includes a pair of left and right first links 17 and second links 18 which are inserted through and connected to link pins 16, a crosshead 19 on the pressure platen which is driven by hydraulic pressure or electricity, and the crosshead 19 It consists of an operating link 20 provided across the first link 17.

  The first link 17 is connected to link receiving portions 21 and 21 provided on the upper and lower sides of the pressure receiving plate 11 in both the upper and lower directions by inserting link pins 22, and the second link 18 is movable on the upper and lower sides. The link pin 24 is inserted and connected to the link receiving portions 23 and 23 provided on the upper and lower sides of the rear panel 11.

  The cross head 19 is threadably engaged with a rotary drive shaft (not shown) provided in a drive fixing portion 25 in the center of the pressure receiving plate, and a pair of upper and lower link mechanisms is moved by the backward movement of the cross head 19. Is bent inward and the mold is opened by moving the movable platen 14 backward, and the pair of upper and lower link mechanisms bent by the forward movement is extended, and the mold is closed and clamped by moving the movable platen 14 forward. Is called.

  Both end portions of each link pin 16, 22, 24 are fixed to the link end portion of the second link 17, the link receiving portion 21 of the pressure receiving plate 11, and the link receiving portion 23 of the movable platen 14 using a set screw 26. is there. The set screw 26 is screwed into a screw hole formed on the same line of each part until the lower surface part is screwed, fitted, or abutted with the side surface of each link pin.

  As shown in FIG. 3, the set screw 26 includes two members: a fixing screw member 27 having a screw having the same outer diameter and the same pitch on the outer peripheral surface, and a presser screw member 28 of the fixing screw member 27. The fixing screw member 27 has a recess 27a formed on a top surface of a rectangular or polygonal shape in which the opening peripheral wall is a tapered surface inclined inward and the internal peripheral wall is fitted to the tightening tool. Further, a convex portion 27b having a smaller diameter shaft than the fixing screw member 27 is provided on the lower surface.

  The presser screw member 28 has a recess 28a formed on a top surface of a rectangular or polygonal shape whose inner peripheral wall is fitted with a tightening tool. Further, a trapezoidal and disc-shaped convex portion 28b having a circumferential surface formed in the same taper so as to be fitted to the opening peripheral edge of the recess 27a of the fixing screw member 27 is formed on the lower surface of the presser screw member 28. It protrudes from the center of the screw shaft. The eccentric dimension a is limited to a dimension (for example, 1.0 to 1.5 mm) within the range of fitting with the opening periphery.

  In such a set screw 26, when the presser screw member 28 is separated from the fixing screw member 27 and overlaps with each other, as shown in FIG. However, in the state where the presser screw member 28 is in contact with the fixing screw member 27 and the eccentric convex portion 28b is completely fitted to the opening periphery of the recess 27a, as shown in FIG. And the center of the convex portion 28a coincide with each other, and a lateral shift a 'equal to the eccentric dimension a is generated there.

This lateral displacement occurs when the convex portion 28b fits into the recess 27a of the fixing screw member 27. Therefore, in the screw hole, the taper surface on one side of the opening peripheral edge of the fixing screw member 27 screwed first is changed later. The taper side surface on the eccentric side of the convex portion 28b of the screw screw 28 that is screwed in presses the taper surface on one side of the peripheral edge of the opening, and the pressing force at this time increases in proportion to the fitting depth of the convex portion 28b. The upper part of the fixing screw member 27 is pressed against the wall surface of the screw hole. This compression makes the fixing screw member 27 difficult to loosen.

  FIG. 4 shows a case where the link pin 16 is fixed to the link end portion of the second link 17 by the set screw 26 of the first embodiment having the above-described configuration. First, the fixing screw member 27 is screwed into the screw hole 17a drilled in the link end. In this screwing, the convex portion 27b on the lower surface of the fixed screw member 27 enters the perforation 16a having a smaller diameter than the screw hole 17a provided in advance at a portion facing the screw hole 17a at the end of the link pin 16, and the convex portion. Repeat until the tip surface is in contact with the bottom of the hole. Next, the presser screw member 28 is screwed.

  In accordance with the screwing of the presser screw member 28, the convex portion 28b at the eccentric position of the presser screw member 28 enters the recess 27a of the fixing screw member 27 screwed in first. When the screw is further screwed in, the taper side surface on the eccentric side of the convex portion 28b presses the taper surface on one side of the peripheral edge of the opening. The pressing force at this time increases according to the fitting depth of the convex portion 28a, and presses the upper part of the fixing screw member 27 against the wall surface of the screw hole. Further, the lower portion of the presser screw member 28 is also pressed against the opposite wall surface of the screw hole by the reaction force of the pressing force.

  As a result, the upper and lower screw members in the screw hole are pressed against each other and tightened to each other, so that there is no clearance between the screw threads that contributes to the looseness of the set screw 26 in the pressed portion, and vibration, impact, load and Even if the stress at the time of bending and stretching is repeatedly received via the link pin 16, the set screw 26 is difficult to loosen, and the link pin 16 is securely fixed. In addition, the link pin 16 is restrained from moving by the convex portion 27b on the lower surface of the fixing screw member 27 fitted in the perforation 16a and is fixed to the link end portion, so that the set screw 26 may be loosened. However, since the link pin 16 does not move in the axial direction and does not rotate in the circumferential direction, the fixed state can be maintained for a long time. Further, the set screw 26 is hardly damaged.

  FIG. 5 shows the case of the set screw 26 according to the second embodiment, in which a tapered hole 16b is provided at a portion facing the screw hole 17a at the link end of the link pin 16, and the conical shape is fitted to the hole 16b. A projecting portion 27 c is projected from the lower surface of the fixing screw member 27, and the projecting portion 27 c and the perforated 16 b are fitted to fix the link pin 16 to the link end portion by the set screw 26.

  FIG. 6 shows a case where the set screw 26 of the third embodiment is used, and a portion facing the screw hole 17a at the link end of the link pin 16 is formed in a partially flat contact surface 16c. A convex portion 27d having a flat front end surface corresponding to 16c projects from the lower surface of the fixing screw member 27, and the link pin 16 is set screw by contacting the front end surface of the convex portion 27d and the contact surface 16c. 26 is fixed to the link end.

  In the above embodiments, the upper surface of the fixing screw member 27 is formed in the recess 27a and the lower surface of the presser screw member 28 is formed in the convex portion 28a so as to be fitted to each other. However, even if the convex part on the fixing screw member side is provided at the eccentric position, the same effect as that of the above embodiment can be obtained. May be.

It is a top view of the mold clamping apparatus of the injection molding machine concerning this invention. It is a side view same as the above. It is a longitudinal cross-sectional view which shows the state (B) which overlap | superposed the state (A) before superimposition of the set screw which consists of two members, a fixing screw member and a presser screw member. It is a longitudinal cross-sectional view of the link end part which shows the fixed state of the link pin by the set screw of 1st Embodiment. It is a longitudinal cross-sectional view of the link end part which shows the fixed state of the link pin by the set screw of 2nd Embodiment. It is a longitudinal cross-sectional view of the link end part which shows the fixed state of the link pin by the set screw of 3rd Embodiment. It is a longitudinal cross-sectional view of the link end part which shows the fixed state of the link pin by the conventional set screw.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Pressure receiving board 13 Tie bar 14 Movable board 15 Double link toggle mechanism 16 Link pin 16a Drilling 16b Taper surface drilling 16c Contact surface 17 First link 17a Screw hole 26 Set screw 27 Fixing screw member 27a Opening peripheral wall is a recess of taper surface 27b Convex part of small-diameter shaft 27c Conical convex part 27d Convex part with flat tip surface 28 Presser screw member 28b Convex part at eccentric position

Claims (4)

A link mechanism in which the first link and the second link are connected to the pin receiving part of the pressure receiving plate and the movable plate by a link pin so that they can be bent and extended, and the end of the link pin of each part is fixed to the link or the pin receiving unit, respectively. In the mold clamping device of the molding machine having the above, when fixing the link and the link pin with the set screw,
It consists of two members, a fixed screw member having the same outer diameter and the same pitch on the outer peripheral surface, and a presser screw member of the fixed screw member,
The fixing screw member and the presser screw member have a recess or a protrusion on the upper surface where a tool can be fitted,
And the presser screw member has a recess or projection that fits with a projection or recess on the upper surface of the fixing screw member on the lower surface,
The convex portion or concave portion on the lower surface of the presser screw member and the concave portion or convex portion on the upper surface of the fixing screw member have a tapered surface that can be fitted to each other, and either one of them is eccentric from the center of the screw shaft. Provided,
The link pin is fixed by pressing the fixing screw member screwed first into the screw hole of the link or pin receiving portion to the side by the tightening force of the presser screw member by the eccentricity and mutual fitting. A mold clamping device for an injection molding machine.   The link pin has a hole having a smaller diameter than the screw hole at a portion facing the screw hole of the link or the pin receiving portion, and a convex portion of a small diameter shaft that fits the hole is formed on the lower surface of the fixed screw member. 2. The mold clamping apparatus for an injection molding machine according to claim 1, wherein the mold clamping apparatus is integrally projected.   The link pin has a perforation in a portion facing the screw hole of the link or the pin receiving portion, and a conical convex portion that fits into the perforation is integrally formed on the lower surface of the fixed screw member. 2. The mold clamping apparatus for an injection molding machine according to claim 1, wherein   The link pin has a flat contact surface at a portion facing the screw hole of the link or the pin receiving portion, and a convex portion having a tip surface formed on a flat surface corresponding to the contact surface, the fixing screw member 2. The mold clamping device for an injection molding machine according to claim 1, wherein the mold clamping device is formed integrally with the lower surface of the injection molding machine.

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