JPS6310258Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a raw material injection device for reaction injection molding (RIM). For more information, see RIM molds and RIM
This invention relates to the mounting technology of the raw material injection head, which plays an important function in connecting the molding press to the molding press.

The reaction injection molding method is a method in which two or more liquid raw materials are mixed just before being injected into a mold, and then reacted and solidified in the mold to obtain a resin product of a desired shape. Used for molding resin bumpers, etc.

In this reaction injection molding method, for example, the RIM polyurethane molding method, as shown in FIG. Conventionally, the work of bringing the mold into close contact with the upper mold 2 has been carried out by adjusting the thickness of the spacer 4 and shim 5 at the bottom of the injection head 1.

However, due to the thermal expansion of the mold due to the mold temperature being raised to about 70°C or the difference in the precision of the height of the injection head, which differs depending on the molding press, the gap between the upper surface of the injection head 1 and the upper mold 2 may change. Problems such as incomplete sealing, creating gaps and burrs on the molded product, and air being trapped during molding, resulting in molding defects, have occurred.

Fine-tuning spacers and shims to improve sealing performance and aligning sealing surfaces at the mold manufacturing stage are all difficult and time-consuming tasks, and even with these measures, it is still difficult to improve the quality of molded products. Since burrs cannot be completely eliminated, more man-hours are required for finishing, all of which cause increased product costs.

The object of the present invention is to solve the above-mentioned problems and provide a device that can adjust the clearance between the RIM mold and the injection head regardless of changes in the mold.

The present inventors believe that the cause of the above-mentioned clearance is the numerically large height of the injection head itself (total height: second,
Indicated by H in Figure 3. ) and numerically small errors due to thermal expansion.The former can be adjusted using a wedge block, and the latter can be adjusted using an elastic body such as a spring spring to ensure the lowest sealing pressure. devised a device.

In other words, the clearance adjustment device between the reaction injection mold and the injection head of the present invention is arranged between the lower end of the raw material injection head whose tip is connected to the upper mold of the reaction injection mold and the lower mold mounting plate. The device is characterized by comprising a pair of wedge blocks and an elastic body, which are arranged in contact with each other at corresponding inclined surfaces.

FIG. 1 explains the positional relationship between the injection head and the clearance adjustment device in the RIM forming press. The injection head 1 is detachably installed on the lower mold 3 side, but it is necessary to ensure sufficient sealing between the injection head 1 and the upper mold 2.
A clearance adjustment device (conventionally spacer 4) is placed at the bottom of the mold to adjust the height after the mold is attached.

FIG. 2 shows a cross-sectional view of the injection head 1 using a conventional spacer 4 and shim 5. Reference numeral 6 represents a raw material supply pipe, and 7 represents a raw material passage within the injection head 1.
The upper mold 2 is provided with a runner 8, and the raw material enters the runner 8 through the sealing surface S and is further supplied to the cavity.

On the other hand, in the device of the present invention, a wedge block and a bell spring are used in place of the spacer 4 and shim 5 described above, allowing continuous and fine adjustment by tightening bolts.

Next, an embodiment of the present invention will be described with reference to FIG.

Embodiment In the apparatus of the present invention, wedge blocks 10a and 10b are arranged on the lower mold mounting plate 9, and an elastic body, for example, a bell spring 11 is placed thereon. The bell spring 11 biases the block 12 to support the upper injection head 1. wedge block 1
0a and 10b are assembled in a holder 13 with their inclined surfaces at the same angle touching each other, and the holder 1
3 is fixed to the lower mold mounting plate 9 with bolts 15 via side plates 14. wedge block 10
Although the block a cannot be moved horizontally because it is blocked by the holder 12, it can be moved vertically by moving the wedge block 10b in the horizontal direction. The wedge block 10b is moved by tightening and tightening the adjustment bolt 16. The spring 11 is placed at a predetermined position on the wedge block 10a, and is fixed by a hole 17 in the block 12, and the block 12 is prevented from moving in any direction other than vertically by the side plate 14. Note that the elastic body such as the flat spring 11 is not necessarily the wedge block 10.
It does not have to be at the top of the injection head 1a or 10b, but may be at any position as long as the height of the injection head 1 can be adjusted. For example, it may be placed between the lower mold mounting plate 9 and the holder 13.

The above-mentioned wedge blocks 10a and 10b are used to adjust the clearance caused by the difference in height of the injection head 1, which differs from molding press to molding press, by adjusting the adjustment bolt 16. The clearance caused by thermal expansion at temperature can be adjusted by pushing up the injection head 1 with the biasing force of the bell spring 11. Note that the injection head 1 is bolted to the lower die 3, although not shown, in order to prevent movement in the horizontal direction.

Comparing the clearance adjustment using the device of this invention and the conventional device, the number of defective molded products is reduced by 50% compared to the conventional device, and the time required to install the injection head and adjust the clearance is reduced by 50%. This resulted in a 70% reduction in finishing man-hours after molding.

As described above, the device of the present invention eliminates the need for complicated adjustment work by replacing conventional spacers and shims, greatly reduces the number of finishing steps after molding, and, on the other hand,
These effects, such as a significant reduction in the number of defective molded products, have combined to contribute to a reduction in product costs.

[Brief explanation of the drawing]

FIG. 1 shows an explanatory view of a RIM mold and a forming press, FIG. 2 shows a sectional view of a conventional device, and FIG. 3 shows a sectional view of an embodiment of the present invention. In the figure, 1... injection head, 2... upper mold, 3...
Lower mold, 4... Spacer, 5... Shim, 6... Raw material supply pipe, 7... Raw material passage, 8... Runner, 9
...Lower mold mounting plate, 10a, 10b...Wedge block, 11...Sara spring, 12...Block, 13...Holder, 14...Side plate, 15...
Bolt, 16...adjustment bolt, 17...hole.

Claims (1)

[Scope of utility model registration request] A pair of wedge blocks and an elastic body are disposed between the lower end of the raw material injection head whose tip is connected to the upper mold of a reaction injection mold and the lower mold mounting plate, and are in contact with each other at corresponding inclined surfaces. A clearance adjustment device between a reaction injection mold and an injection head, characterized by the following: