JPS5837892B2 - How to make plastic safety pins - Google Patents

Description

[Detailed Description of the Invention] The present invention? j. This relates to a method of manufacturing a plastic safety pin, the purpose of which is to separate the pin receiving part and main body of the plastic safety pin so that the resin does not flow into the coil spring receiving groove. To easily manufacture a safety pin that does not prevent movement of the pin due to inflow.

By setting the spring holder in a secondary shape mold and shaping the main body, the pins can be installed uniformly and reliably, allowing automatic mass production of perfect products that will not be damaged.

To reduce product costs by attaching the opening of a coil spring receiving groove to a mold or blocking it with a small protrusion, by using an inexpensive mold to perform trouble-free molding.

etc. Next, an embodiment of the method according to the present invention will be described below with reference to the drawings.

In the figure, reference numeral 1 indicates a pin receiving part that has been shaped using a primary mold (not shown in the drawing).A receiving groove 4 for accommodating the coil spring 3 of the pin 2 is provided at the inner lower part of the part, and from this receiving groove 4 upward A spring foot 5 is made to protrude, a pin 2 is made to protrude downward, and a fused portion 6 is provided at the upper part to form an oval shape of the main body, which will be described later.

7 is a mold for secondarily shaping the main body 8, in which a recess 9 into which the fused part 6 and below of the pin receiving part 1 are fitted and a molded hole 11 forming a pin hooking part 10 are provided in the upper part b; has 12 decorative holes in the center.
When a hollow-shaped nitrogen gap 13 is provided that forms a main body 8 having a
A small protrusion 14 is provided in the pin receiving part 1 fitted into the lower mold recess 9 to close the opening into the molding space 13 of the coiled spring receiving groove, and the small protruding piece 14 is provided at the center of the upper part to match the spring foot 5. Concave 1
It is shaped like 5.

Reference numeral 16 denotes a resin flow path provided in the mold 7, which guides the resin to be injected into the molding space 13.

17 is a movable part in the lower mold a, which is a diagonal guide 1 during mold clamping.
8 to a fixed position to align the certain shaped spaces 13 and 11, and when opening the mold, move the movable part 17 outward,
This allows the pin groove 19 shaped portion 20 in the pin hooking portion 10 to be pulled out laterally.

Since the method according to the present invention uses the mold as described above, the pin receiving part 1 as shown in FIG. If this pin receiving part 1 is fitted into the recess 9 of the lower mold a of the mold 7 for secondary shaping the main body 8 as shown in FIG. 2, the small protrusion 14 attached to the lower mold a will be Since it hits the inner end surface of the pin receiving part 1 and closes the part where the coiled spring receiving groove 4 communicates with the certain shaped space 13, in this state, after placing the clay mold b on the lower mold a and clamping the mold, When molten synthetic resin is injected into the resin flow path 16, the resin flows from the flow path 16 into the molding space 13.11 and flows into the space 13.11.
11 and form the main body 8 and the pin hook part 10 having the same shape as the space 13. The small projecting piece 14 completely prevents the resin from flowing into the coil spring receiving groove 4, so even if the spring foot 5 is inserted into the main body 8 and becomes immovable, the coil spring 3 part prevents the resin from flowing into the receiving groove 4. Since no inflow occurs, it is possible to easily manufacture a safety pin made of synthetic resin that has flexibility and allows the pin 2 to be easily hooked onto and removed from the pin hooking portion 10.

In particular, in this method, the pin is housed in the primary molded pin receiving part and set in the secondary molding die to form the main body, so the pin receiving part and the main body are integrated by fusion. hand,
There is absolutely no damage, and since the position and angle of the pin to the main body are regulated by the mold, it is done uniformly and securely, and there is no possibility of loosening or detachment.
Since the pin is made of resin, it has a good appearance, is easy to use, and has excellent safety, and is highly effective as a method for mass-producing safety pins at low cost.

[Brief explanation of drawings]

The drawings show one embodiment of the method according to the present invention.
The figure is a rear view of the product manufactured by this method, Figure 2 is a perspective view of the primarily formed pin receiver, Figure 3 is a partial view showing the pin receiver set in the lower mold, and Figure 4 (shippin Fig. 5 is a sectional view showing a state in which the receiving part is set in the lower mold and the mold is clamped, and Fig. 5 is a sectional view showing a state in which the mold is clamped and molded. Pin, 3 is a coiled spring, 4 (1
7 is a mold, 13 is a shaped space, and 14 is a small protrusion.

Claims (1)

[Claims] 1. A pin receiving part having a coil spring receiving groove in the pin and a fusion part to the main body is pre-formed and placed, and this pin receiving part is put into a secondary mold for forming the main body and the spring foot is fused. The coil spring receiving groove is set so that it protrudes into the molding space, and the part where the coil spring receiving groove opens into the mold space is closed by a small protrusion attached to the secondary mold. A method of manufacturing a plastic safety pin, characterized in that the main body is oval-shaped by resin injection to prevent resin from flowing into the spring receiving groove.