Plastic article or earthenware shaping or treating: apparatus – Distinct means to feed – support or manipulate preform stock... – Opposed registering coacting female molds
Reexamination Certificate
1999-05-28
2002-05-07
Nguyen, Nam (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Distinct means to feed, support or manipulate preform stock...
Opposed registering coacting female molds
C425S129100, C425S544000, C425S594000, C425SDIG002
Reexamination Certificate
active
06382945
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a molding apparatus for molding resin to seal an electronic device, and more specifically to a resin plunging mechanism for the molding apparatus for plunging resin tablets into the molds in the molding apparatus.
FIGS. 1 and 2
show a molding apparatus for molding resin to seal an electronic device, for example, an IC according to U.S. Pat. No. 5,435,953. This structure of molding apparatus comprises a plurality of plungers
12
a
moved in and out of cavities
14
a
and
15
a
in stationary upper mold
10
a
and movable lower mold
11
a
. The plungers
12
a
each have a plunger head
13
a
. When the plungers
12
a
are moved into the cavities
14
a
and
15
a
in stationary upper mold
10
a
and movable lower mold
11
a
, resin tablets
16
a
are plunged into the molds
10
a
and
11
a
. The molding apparatus further comprises two load elements
17
a
driven by a motor
18
a
through a respective belt transmission mechanism
19
a
and a transmission rod
22
a
to move two worm gear and worm mechanisms
20
a
, causing the worm and worm gear mechanisms
20
a
to move plunger holder means
21
a
and the plungers
12
a
up and down. This plunging mechanism is complicated. Pitch error and deformation of the worm gear and worm mechanisms
20
a
and the belt transmission mechanism
19
a
affects the movement of the plunger holder means
21
a
, causing the plunger heads
13
a
unable to be synchronously moved into the cavities
14
a
and
15
a
in the molds
10
a
and
11
a
, therefore the plunger heads
13
a
tend to be damaged. Furthermore, during the operation of the molding apparatus, heat (molding temperature is as high as 170° C.) is transferred from the molds
10
a
and
11
a
through plunger holder means
21
a
to the load elements
17
a
and guide bars
33
a
causing the load elements
17
a
and guide bars
33
a
to deform (because the worm and worm gear mechanisms
20
a
and guide bars
33
a
are securely limited on the movable plate
23
a
, and no horizontal gap is left between the mechanisms
20
a
and guide bars
33
a
and the movable plate
23
a
to absorb the space expansion of the load elements
17
a
and the guide bar
33
a
). When the load elements
17
a
deform, the plungers
12
a
are forced to tilt in different directions, and the electronic device molding quality is affected. So the plunger heads
13
a
are damged easily.
SUMMARY OF THE INVENTION
The present invention provides a plunging mechanism for a molding apparatus which eliminates the aforesaid drawbacks. In the plunging mechanism according to the present invention, a ball screw is rotated to move a movable base plate and two load elements at the movable base plate, enabling a plunger holder which is supported on the load elements to be moved with the movable base plate along guide bars, so that plungers which are securely mounted on the plunger holder are positively forced into cavities in upper and lower molds to plunge resin tablets.
REFERENCES:
patent: 5059379 (1991-10-01), Tsutsumi et al.
patent: 5118271 (1992-06-01), Baird et al.
patent: 5378140 (1995-01-01), Asano et al.
patent: 5429488 (1995-07-01), Neu
patent: 5435953 (1995-07-01), Osada et al.
patent: 5451154 (1995-09-01), Schaars
patent: 5626886 (1997-05-01), Ishii
patent: 5851559 (1998-12-01), Scribner et al.
patent: 5989471 (1999-11-01), Lian et al.
patent: 6030569 (2000-02-01), Yu
Chen Li-Wei
Hung Kuang-Yuan
Lee Sheng-Lang
Liang Muh-Wang
Industrial Technology Research Institute
Nguyen Nam
Nguyen Thu Khanh T.
Rabin & Berdo P.C.
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