Method of stripping a molded article

A molding method comprises a step of fitting a movable mold to a stationary mold and filling a molten resin into a cavity formed by the mold fitting; a step of separating the movable molds; a step of releasing a molded product held by one or more push pins while shifting the push pins; a step of holding the molded product by a guide having a .]. shaped sectional view; and a step of releasing the molded product from the push pins to pass the molded product along the guide having a .]. shaped sectional view.

BACKGROUND OF THE INVENTION 
The present invention relates a method of molding a plastic etc. and a 
molding machine. 
In the conventional method of molding a plastic etc., a molded product is 
put out from a female mold by using a push pin to freely fall down on a 
conveyor or to directly fall into a storage vessel at random so as to be 
arranged by a hand operation. 
It has been proposed to pass the molded products through rails to a storage 
place (Japanese Unexamined Patent Publication No. 128754/1975). However, 
the molded products have not been smoothly guided to the storage place 
because of the construction for throwing the molded products to the 
position of the rails for the mold. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a molding method having 
high productivity while smoothly passing molded product without any 
damage. 
The foregoing and other objects of the present invention have been attained 
by providing a molding method comprising a step of fitting a movable mold 
to a stationary mold and filling a molten resin into a cavity formed by 
the mold fitting; a step of separating the movable molds; a step of 
releasing a molded product held by one or more push pins while shifting 
the push pins; a step of holding the molded product by a guide having a 
.]. shaped sectional view; and a step of releasing the molded product from 
the push pins to pass the molded product along the guide having a .]. 
shaped sectional view.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawings, the molding method of the present invention will 
be illustrated. 
In FIG. 1, the reference numeral (13) designates a movable platen which 
slides under a guide of divers (23) fixed on a stationary platen (12). A 
stationary mold (10) is mounted on the stationary platen (12) and a 
movable mold (11) is mounted on the movable platen (13). Accordingly, the 
movable mold (11) is fitted to the stationary mold (10) by moving the 
movable platen (13) toward the stationary platen (12). On the contrary, 
the molds are separated by departing the movable platen (13) from the 
stationary platen (12). 
Thus, the molds are fitted and a molten resin is fed through a runner (14) 
from the side of the stationary platen (12) as shown in FIG. 2 while 
applying the pressure to the movable platen (13) and it is filled in a 
cavity of a space formed between a concavo part (18) and a core (19) to 
carry out the molding. After cooling the resin to be solidified, the mold 
separation for departing the movable mold (11) from the stationary mold 
(10) is carried out as shown in FIG. 3 and the molded product (21) is 
remained in the movable mold (11) under contacting with the core (19). 
On the other hand, when a signal indicating the initiation of the mold 
separation is received, a pushing cylinder (17) is actuated as shown in 
FIG. 1 to move a push rod (16) toward the stationary platen (12) and to 
push a push plate (20). Push pins (15) mounted on the push plate (20) are 
passed through the core (19). The molded product (21) is released from the 
mold through the holes as shown in FIG. 4. 
One of the significant advantages of the present invention is found in the 
releasing step. 
In the conventional molding method, the edges of the push pins (15) are 
disposed at the same plan of the core (19) whereby when the push pins (15) 
are actuated to release the molded product (21) from the core (19), the 
molded product falls down under its dead weight. 
On the contrary, in accordance with the present invention, at least one or 
more preferably several push pins (15) are projected for a slight distance 
from the core surface (19). Thus, the molded product (21) includes the 
push pins (15). Even though the push pins (15) are actuated to separate 
the molded product (21) from the core (19), the molded product (21) is 
still held by the push pins (15) as shown in FIG. 4. 
Thus, rails having a .]. shaped sectional view (22), (22') approach to the 
molded product (21) held by the push pins (15) so as to hold the molded 
product (21) from both sides by the rails as shown in FIG. 1. 
The driving of the rails having a .]. shaped sectional view will be further 
described by certain examples. 
When the push cylinder (17) is actuated to return the push pins (15), the 
molded product (21) intends to return together with the push pins (15) 
however, the rails having a .]. shaped sectional view (22), (22') hold the 
molded product (21) whereby the molded product (21) is released from the 
push pins (15) and the released molded product (21) falls down under the 
guidance of the rails (22), (22') as shown in FIG. 5. 
The rails having a .]. shaped sectional view (hereinafter referring to as 
the rail) will be described. 
In FIGS. 6 and 7, the reference numeral (39) designates a shaft which is 
mounted on support blocks (40) mounted on the upper surface and the lower 
surface of the movable mold (11). Two pairs of slidable blocks B (37), 
(37') are fitted through the shaft (39). Each slide bearing (38) is buried 
in each of the slidable blocks B (37), (37') to make smooth sliding. 
The slidable blocks B (37) are connected with a connecting plate (36) and 
the slidable blocks B (37') are connected with a connecting plate (36'). 
The rails (22) and (22') are respectively connected to the slidable blocks 
B (37) and (37'). The reference numeral (33) designates a plate cam having 
a projected portion and the sectional width is varied depending upon the 
mold fitting and the mold separation. The reference numerals (34), (34') 
designate cam followers mounted on each connecting plate (36), (36') and 
are always pushed on both side surfaces of the plate cam (33) with a 
spring (35). 
When the sectional width of the plate cam (33) becomes narrow, the 
connecting plates (36), (36') are slided toward the center, whereby the 
rail (22) is shifted to the right side and the rail (22') is shifted to 
the left side so as to approach each other. When the sectional width of 
the plate cam (33) become wide, the connecting plates (36), (36') are 
outwardly slided from the center whereby the rail (22) is shifted to the 
left side and the rail (22') is shifted to the right side so as to depart 
each other. 
The reference numeral (41) designates a bolt for mounting the plate cam on 
the stationary mold (10) and (42) designates a relief groove formed on the 
stationary mold (10) for containing the rails (22), (22') during the time 
fitting the stationary mold (10) and the movable mold (11). When the 
molding step is finished and the detouching step is initiated, the cam 
followers (34), (34') are moved along the side surfaces of the plate cam 
(33) so as to deepen the cross of the connecting plates (36), (36'). The 
rails (22), (22') approach to the width for holding the molded product 
(21) and stop at the position of the narrowest width of the plate cam (33) 
as shown in FIG. 8. 
FIG. 9 shows the second embodiment of the present invention. 
When the stationary mold (10) and the movable mold (11) are fitted, the 
angular pin (32) is at the position (32') while being inserted into a 
slant hole (31') formed in the slidable block (30'). 
When the mold releasing step is initiated, the angular pin (32) is departed 
from the movable mold (11) and the slant hole (31') is shifted toward the 
position (31) and the slidable block A (31') is shifted toward the 
position (30). Accordingly, the rail (22) is inwardly shifted. 
The angle of the angular pin is reversed whereby the other rail is 
outwardly shifted. 
When the molds are fitted, the angular pin (32) is inserted into the slant 
hole (31) whereby the rail (22) is returned to the position (22'''). 
FIG. 10 shows the third embodiment of the present invention. 
The angular pin (32) is used as in the second embodiment. Thus in this 
embodiment, a taper is given at the bottom of the slidable block A (30) 
whereby the slidable block A (30) is slided while rising. Accordingly, 
under the mold fitting condition, the slidable block A is at the position 
(30') whereby the rail (22) is not inwardly shifted. Accordingly, it is 
unnecessary to have a relief groove (42) for the rail in the first 
embodiment nor to have a step difference of the stationary mold in the 
second embodiment. 
FIG. 11 shows the fourth embodiment. 
A rack (43) molded on the stationary mold (FIG. 1 etc.) is moved to the 
arrow line direction by the mold separation, and a pinion (44) interlocked 
with the rack (43) is turned to the arrow line direction to rotate the 
shaft (28) whereby the rail (22) mounted on the rotary piece (29) is 
shifted from the position (22''') to the position (22). 
In this embodiment, the rail (22) is not shifted under the mold fitting 
condition, and accordingly, the surface of the stationary mold can be flat 
as the same with that of the third embodiment. 
FIG. 12 shows the fifth embodiment. 
The cylinder for rail ascent and descent (24) is actuated by receiving a 
signal for the finish of the mold separation step and a signal for the 
finish of the push out of the molded product, whereby the rail (22) is 
shifted to the position (22") and the molded product (21) held by the push 
pins (15) are held by the rails (22"). Then, the push pins (15) are 
returned while holding the molded product (21) by the rails (22") so as to 
separate the molded product (21) from the push pins (15) and the molded 
product (21) falls down along the rails (22") and the arrangement for the 
next step is given. 
In this embodiment, the mold is not modified but only the timings of the 
push pins (15) and the mold operation are varied. The advantage of this 
embodiment is significant. 
In the conventional operation, a molded product discharging machine has 
been used. Such machine has carried out many complicated operations such 
as a descent and a forward shifting of an arm, a suction, a reward 
shifting and an ascent, a direction change and a descent of the arm and a 
release of the molded product. Accordingly, it has disadvantages of high 
cost and low processability. 
The reference numeral (26) designates a conveyor for passing the molded 
product (21) to the next step and (27) designates a stopper for preventing 
the falling of the molded product (21) over the conveyor (26). These parts 
are commonly used in all of the embodiments of the present invention. 
In accordance with the molding method of the present invention, the molded 
products are smoothly passed whereby the productivity is high and the 
molded products are not injured.