JPH0227966Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field> The present invention relates to a mold clamping device for an injection molding machine, etc., and particularly to a mold clamping device that can automatically pull out tie bars without applying a preload.

<Prior art> In general, in devices such as injection molding machines that perform assembly by strongly tightening tie bars between a fixed plate and a mold clamping cylinder, the mold clamping force is several percent higher than the maximum mold clamping force of the device. Assembling is performed by applying a preload to the tie bar, which is a condition in which the tie bar is stretched by force. Applying this preload to the tie bar requires a narrow tie bar diameter.
It is lighter in weight and saves on material costs.

However, when pulling out tie bars for mold replacement, etc., the work is extremely complicated.
The work is time consuming and the tie bar pulling device is also expensive.

Pulling out a preloaded tie bar is only possible after the preload is released because the tie bar nut tightening the tie bar is strongly pressed against the fixing plate or mold clamping cylinder while the preload is still applied. be. Therefore, pulling out the tie bar involves first releasing the preload and then pulling the tie bar.

<Purpose of the invention> The present invention eliminates the disadvantages of mold clamping devices such as injection molding machines that have tie bars with a preload as described above, and eliminates the disadvantages of mold clamping devices such as injection molding machines that have tie bars that are not preloaded. To provide a mold clamping device capable of simply and easily pulling out tie bars at low cost without requiring two steps.

<Structure of the invention> In order to achieve the above-mentioned object, the inventors of the present invention inserted a tie bar with threaded portions at both ends between a fixed plate of an injection molding machine, etc. and a mold clamping cylinder, etc., and screwed a tie bar nut at one end. In a mold clamping device such as an injection molding machine, the other end is screwed together with a split nut split in two along a dividing line passing through the axis of the tie bar to tighten between the fixed plate and the mold clamping cylinder, etc. a nut rotation mechanism that tightens and loosens the split nut; a nut engagement mechanism that opens and closes the split nut from a direction perpendicular to the axis of the tie bar and engages and disengages the tie bar threaded portion and the split nut threaded portion; A split collar provided on the split nut side of the tie bar that regulates the length of the tie bar inserted into the fixed plate or mold clamping cylinder;
A tie bar lock mechanism (1) that locks the movable plate and the tie bar in order to move the tie bar in a predetermined movement direction by the forward and backward movement of the movable plate; and a tie bar lock mechanism (1) that locks the movable plate and the tie bar; A tie bar is provided, which locks the tie bar with the fixing plate or mold clamping cylinder, etc. during the tie bar removal or insertion work, and prevents the tie bar from being locked while the tie bar is locked by the tie bar locking mechanism (1). It is characterized by the provision of a lock mechanism (2).

<Embodiment> Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2. Reference numeral 11 denotes a tie bar with threaded portions 11a at both ends, and the fixing plate 12 and the flange portion 13 of the mold clamping cylinder 24. A tie bar nut 14 and a split nut 15 are used to tighten the space between the two.
16 is a hydraulic cylinder, and as shown in FIG. 2, a piston rod 17 is attached to the split nut 15. As the piston rod advances and retreats, it is rotated about the split nut 15 as shown by the chain line 15a, and the tie bar is rotated. It is a nut rotation mechanism that tightens and loosens the threaded portion 11a and the threaded portion of the split nut 15.

18 is a hydraulic cylinder and its piston rod 19
A toggle mechanism 20 is provided at the tip of the split nut 15 to open and close the split nut 15 from left to right in the figure with a fulcrum 21 as the center. Therefore, when the piston rod 19 advances or retreats, it closes and opens, respectively.For example, when opening the split nut 15 that is in a tightened state, the nut rotation mechanism moves it to the position indicated by the chain line 15a, and then the hydraulic cylinder 18 moves it to the position indicated by the chain line 15a. Toggle mechanism 2
When 0 is in the loosening direction, the split nut 15 comes off from the threaded portion 11a of the tie bar. Conversely, in order to tighten the split nut 15 in the open state to the tie bar 11, the hydraulic cylinder 18 should push the toggle mechanism 20 left and right at the position shown by the chain line, and the split nut 15 will tighten the tie bar 11 from the left and right. With clamping, the threaded parts will fit together. Reference numeral 22 denotes a split collar that regulates the length by which the tie bar 11 is inserted into the fixed plate 12.

Reference numeral 23 denotes a movable plate to which a movable mold (not shown) is attached, and the fixed mold attached to the fixed plate 12 is opened and closed by pressure oil acting on a mold clamping cylinder 24. Reference numeral 25 is for locking the tie bar 11 to the movable plate 23 by hydraulic pressure acting on the tie bar lock mechanism (1). Reference numeral 26 is for locking the flange 13 of the mold clamping cylinder and the tie bar 11 by hydraulic pressure acting on the tie bar lock mechanism (2).

Both tie bar lock mechanisms are designed to operate in reverse when the tie bar 11 is inserted or removed. That is, when the movable plate 23 and the tie bar 11 are engaged, the movable plate 23 closes the mold clamp and the cylinder 2.
4, the tie bar 11 moves in the insertion or removal direction in synchronization with the movement of the moving plate 23. At that time, the lock mechanism (2) attached to the flange 13 of the mold clamping cylinder locks with the tie bar 11. This is because it will not be possible to move if it is closed. Further, when the moving plate 23 releases the locking with the tie bar 11 and returns to the original position to lock the tie bar 11 again in order to move the tie bar 11 again, the locking mechanism (2) locks the tie bar 11 again.
1 is adapted to be locked to the flange portion 13.

<Operating operation> The structure is as described above. Next, the operating operation will be explained using the case of removing the tie bar as an example. First, the hydraulic cylinder 16 moves the split nut 15 to the second
As shown in the figure, the position shown by the chain line 15a is reached, and the tightening is loosened. Next, the toggle mechanism 20 is loosened by the hydraulic cylinder 18, the split nuts 15 are opened left and right, and the threaded portions 11a of the tie bars 11 are disengaged, so that the tie bars 11 are released from the tightened state and can be removed freely. Subsequently, the tie bar lock mechanism (1) 25 attached to the movable plate 23 locks the tie bar 11 to the movable plate 23 when the movable plate 23 is at the backward limit position. Next, the moving plate 23 moves forward (in the mold clamping direction), and the tie bars 11 move forward together.

When the moving plate 23 stops at the forward limit, the directional switching valve 27 switches from the previous position a to the b position,
The tie bar lock mechanism (2) operates to lock the tie bar 11 to the mold clamping cylinder flange 13, and the tie bar lock mechanism (1) 25 releases the lock of the tie bar 11. Subsequently, the movable plate 23 returns from the forward limit to the backward limit and engages the tie bar lock mechanism (1) 25 again.
to lock the tie bar 11 and move forward. In this way, the forward movement is repeated several times to move the tie bar 11 each time, and the tie bar 21 is pulled out toward the split nut. Similarly, the tie bar 11 can be inserted in such a way that the tie bar locking mechanism (1) 25 locks the tie bar 11 when the movable plate moves in the backward direction in the opposite direction to this pulling out operation.

<Effects> Since the present invention operates with the configuration described above, it has a much better effect than the mold clamping device assembled with preloaded tie bars as originally proposed.
Simple and easy to operate.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of the present invention. FIG. 2 is a view taken along the Z arrow in FIG. 11...Tie bar, 12...Fixing plate, 1
3... Flange of mold clamping cylinder, 15... Split nut, 16... Hydraulic cylinder (for nut rotation mechanism),
18...Hydraulic cylinder (for nut engagement mechanism) 2
0... Toggle mechanism, 23... Moving plate, 25
... Tie bar lock mechanism (1), 26... Tie bar lock mechanism (2), 27... Directional switching valve.

Claims (1)

[Scope of utility model registration request] A tie bar with threaded portions formed on both ends is inserted between a fixed plate mold clamping cylinder etc. of an injection molding machine, etc., one end is screwed with a tie bar nut, and the other end is split into two at a dividing line passing through the axis of the tie bar. In a mold clamping device such as an injection molding machine in which a split nut is screwed together to tighten between the fixed plate and a mold clamping cylinder, a nut rotation mechanism for tightening and loosening the split nut; and a tie bar shaft. a nut engagement mechanism that opens and closes the split nut from a direction perpendicular to the split nut, and also engages and disengages the tie bar threaded part and the split nut threaded part; and a tie bar that regulates the length of the tie bar inserted into the fixing plate or mold clamping cylinder, etc. A split collar provided on the split nut side; installed on the moving plate, and when the split nut is disengaged from the threaded part, the moving plate and the tie bar are used to move the tie bar in a predetermined movement direction by the forward and backward movement of the moving plate. A tie bar lock mechanism (1) is provided on a fixing plate or mold clamping cylinder, etc. at the opposite end of the tie bar split nut, and is installed on a fixing plate or mold clamping cylinder, etc. at the opposite end of the tie bar to prevent the tie bar from interlocking with the fixing plate or mold clamping cylinder, etc. during the removal or insertion of the tie bar. A mold clamping device for an injection molding machine, etc., comprising a tie bar lock mechanism (2) that is locked and is not locked while the tie bar of the tie bar lock mechanism (1) is locked.