JPH02160199A - Pressing force measuring instrument - Google Patents

Abstract

PURPOSE:To exactly obtain the pressing force which is applied between a movable side die and a fixed side die by fixing one end of a distance measuring rod to one of a rear platen or a fixed platen and placing the other end in the other platen position. CONSTITUTION:In a regular operation, in a clamping part 1, a toggle mechanism 7 presses a movable platen 4 against a fixed platen 3 by driving of a clamping motor 12, and a movable side die 13 and a fixed side die 14 are locked up. In this case, even if effective length L is varied, since length of a distance measuring rod 15 in which only one end is fixed is not varied, a position variation is generated in a detection point 17 of a dial gauge 16, and it is detected and displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a pressing force measuring device for a mechanism that presses (clamps) a movable mold against a fixed mold with a predetermined force, such as a press machine or an injection molding machine.

In conventional injection molding machines, the fixed side mold is attached to the fixed platen, the movable side mold is attached to the movable platen, and the movable die is moved by an expansion mechanism (toggle mechanism, motorized linear motion mechanism, etc.) installed between the movable platen and the rear platen. is pressed into a fixed mold and clamped.

In this case, the rear platen and the fixed platen are connected by a tie rod, and the tie rod receives the reaction force during mold clamping.

Therefore, if we examine the elongation of the tie rod, we can determine the mold clamping force (
You can see how much pressure (pressure force) is being applied.

Conventionally, for example, after replacing the mold and adjusting the mold thickness, in order to check whether the predetermined mold clamping force is actually being applied accurately, a fixed platen a is used as shown in Figure 2. and tie bar nut C for fixing tie bar b to this.
By placing a load sensor d between the
A deep hole e is formed in one end of the tie bar on the fixed platen a side in the axial direction from the end, and a distance measuring rod f is attached to this with one end fixed to the bottom of the deep hole e, while a tie bar nut C, etc. is fixed. A measuring person Q, such as a dial gauge, is fixed on the side of the platen a to detect the positional displacement between the fixed platen a and the end face of the distance measuring frame f.

However, the load sensor is expensive and requires a detection circuit for this purpose, so it has the disadvantage of high cost.In addition, in the case of the distance measuring frame f, it is difficult to process one end of the tie bar. However, since the dimensions cannot be increased, the amount of positional displacement to be detected is small, resulting in a large error.

The above points also apply to press machines having similar mechanisms.

Problems to be Solved by the Invention It is an object of the invention to provide a pressing force measuring device that can more accurately determine the degree of pressing force applied to a mold in a press machine or an injection molding machine with a simple configuration.

Means for Solving the Problems A movable platen is provided between a rear platen and a fixed platen that are connected by a tie bar, and a mechanism is configured to press the movable platen toward the fixed platen.

A distance measuring frame is arranged between the rear platen and the fixed platen, one end of the ranging frame is fixed to either the rear platen or the fixed platen, and the other end is arranged at the position of the other platen.

A measuring tool is provided on the other platen.

The measuring tool detects and displays a positional change between the distance measuring frame and one point on the other end side with respect to the other platen.

For production The distance measuring frame transmits the elongation of the tie bar to the measuring tool.

The measuring tool measures and displays the elongation of the tie bar.

Embodiment FIG. 1 shows a mold clamping section 1 in an injection molding machine, and a machine stand 2.
A fixed platen 3 is fixed on top, and a movable platen 4 and a rear platen 5 are arranged in parallel behind it.

The rear platen 5 is connected to the fixed platen 3 by four tie bars 6, and the movable platen 4 is connected between both platens by using the tie bars 6 as a guide, and by a toggle mechanism 7 as a pressing mechanism provided between the two platens. It is attached so that it can be moved back and forth relative to 3.

Each tie bar 6 has its rear end penetrated through the rear platen 5, and a threaded portion formed in that part is screwed into a sprocket nut 8 mounted on the rear surface of the rear platen 5, and its front end is connected to the fixed platen 3. The tie bar nut 9 is screwed through the hole. Therefore, the effective length (L) of each tie bar 6 is determined by the tie bar nut 9 and sprocket nut 8.
has been decided.

Note that this length can be adjusted by rotating the sprocket/nut 8, and in reality, the chain 10 that is hooked around each sprocket/nut 7 is connected to the mold thickness adjustment motor 11.
The distance between the four tie bars 6 (that is, the distance between the rear platen 5 and the fixed platen) is synchronously adjusted. Since the pressing mechanism is the toggle mechanism 7, this adjustment is necessary for adjusting the mold thickness after replacing the mold. For this reason, the rear platen 5 is configured to be able to move back and forth over a short distance with respect to the machine base 2.

The toggle mechanism 7 is driven by a mold clamping motor 12.

Reference numeral 13 is a movable mold, and reference numeral 14 is a fixed mold.

At the upper part between the rear platen 5 and the fixed platen 3, a distance measuring frame 15 made of metal or hard resin is arranged in parallel with the tie bar 6, one end of which is screwed into the fixed platen 3 and fixed, and the other end is fixed by passing through the rear platen 5. Supported in a slidable manner.

Further, a dial gauge 16 for detecting positional displacement is fixed to the rear platen 5 as a measuring tool, and its detection point 17 is set on the end surface of the distance measuring frame 15 on the other end side.

In normal operation, the mold clamping section 1 is operated by the mold clamping motor 12.
When driven, the toggle mechanism 7 presses the movable platen 4 against the fixed platen 3 and locks up the movable mold 13 and the fixed mold 14. During lock-up, the effective length (L) of each tie bar 6 is slightly extended, thereby maintaining the mold clamping force. The amount of elongation is about 1.0 mm (mold clamping force 30t, tie bar diameter 50φ) and about 1.5 mm (mold clamping force 300t, tie bar diameter 130φ).

At this time, even if the effective length (L) changes, the length of the distance measuring rod 15, which is fixed at one end, does not change, so a positional displacement occurs at the detection point 17 of the dial gauge 16, and this is detected. will be displayed. The dial gauge 16 is returned to zero at the beginning of detection.

When the mold has been replaced and the mold thickness has been adjusted, perform a test run to lock up the mold and read the display on the Daicel gauge at that time before returning to normal operation. It is possible to know in advance whether adjustments have been made to apply mold clamping force.

Note that the display on the dial gauge may directly indicate positional displacement (i.e., the extension opening of the tie bar), or
The force may be converted from the cross-sectional area and Young's modulus of the tie bar 6.

The amount of elongation detected by the dial cage 16 is the result of integrating the amount of deformation of each part, such as compressive deformation of the toggle mechanism during the mold clamping operation, and is approximately commensurate with the mold clamping force being applied.

In this case, the dial gauge 16 has one end fixed to the fixed platen 3, and a distance measuring rod 15 having a length reaching the rear platen.
Since the elongation of the tie bar 6 is detected using the other end as a reference, the detected amount is large, and therefore the error is small.

Further, the structure is simple because one end of the distance measuring rod 15 is fixed to the fixed platen 3, the other end is passed through the rear platen 5, and the contact point of the dial gauge 16 is disposed at the end.

Although the embodiments have been described above, one end of the distance measuring rod may be fixed to either one of the fixed platen and the rear platen, and the other end does not necessarily need to be passed through the other platen.

However, if the distance measuring rod is bent, it is preferable to support it in some way.

The method of fixing one end of the distance measuring rod is not limited to screwing. For example, the end of the distance measuring rod may be formed into a shouldered screw, and a nut may be screwed into the portion protruding from one platen to secure the rod.

The measuring tool is not limited to a dial gauge, but may be a linear scale. Furthermore, the detection point of the measuring tool and the distance measuring rod is not limited to the end surface on the other end side of the distance measuring rod, but may be set at one point on the other end side.

Further, the present invention can be applied to mold clamping devices and press devices in which the suppression mechanism is not a toggle type, for example, a direct-acting type in which a movable platen is directly moved by a ball screw/nut mechanism driven by a mold clamping motor. .

Effects of the invention The pressing force applied between the movable mold and the fixed mold can be reduced by
With a simple configuration, you can understand more accurately.

[Brief explanation of the drawing]

FIG. 1 is a front view, FIG. 2 is a front view of a conventional example, and FIG. 3 is a front view of the conventional example without showing main parts. 3...Fixed platen, 4...Movable platen, 5...
・Rear platen, 6... Tie bar 7... Toggle mechanism, 13... Movable side mold, 14... Fixed side mold, 1
5... Distance stick, 16... Dial gauge (measuring tool)
.

Claims (1)

[Claims] In this mechanism, a movable platen is provided between a rear platen and a fixed platen that are connected by a tie bar, and the movable platen is pushed toward the fixed platen.One end of the ranging rod is fixed to either the rear platen or the fixed platen, and the other end is fixed to the other. A pressing force measuring device, comprising: a measuring tool disposed at the platen position of the other platen to detect and display a change in position between the other platen and one point on the other end side of the distance measuring rod.