Metal working – Means to assemble or disassemble – Means to assemble electrical device
Reexamination Certificate
1998-01-23
2001-09-25
Young, Lee (Department: 3729)
Metal working
Means to assemble or disassemble
Means to assemble electrical device
C029S743000, C072S094000, C074S569000, C074S055000
Reexamination Certificate
active
06293003
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to an electronic component mounting apparatus for mounting electronic components onto a circuit board and, more particularly, to an electronic component mounting apparatus in which a pickup nozzle (suction nozzle) is moved up and down by using a cylindrical cam.
2. Description of Related Art
As a prior art example of the electronic component mounting apparatus in which a pickup (suction) nozzle unit is moved up and down by using a cylindrical cam, one as described in Unexamined Japanese Patent Publication No. 3-8398, which is provided with a cylindrical cam having a fixed-portion and up/down-movable-portion composite cam groove over the entire circumference, is described with reference to
FIGS. 8
to
12
. It is noted that some cylindrical cams have only fixed cam grooves. In such a case, in the following description of the prior art, the fixed-portion and up/down-movable-portion composite cam groove is replaced by a fixed cam groove, where the fixed cam groove moves a pickup nozzle unit to a specified working position, so that the pickup nozzle unit is positioned at the specified working position, and thereafter a pickup nozzle of the pickup nozzle unit is moved up and down by a rotating cam and a lever mechanism.
Referring to
FIG. 8
, on a support base
116
are fixed an index unit
101
, a cylindrical cam
105
, plate cams
109
a
,
109
b
, levers
108
a
,
108
b
which are actuated by the plate cams
109
a
,
109
b
, and springs
110
a
,
110
b
which bias the levers
108
a
,
108
b
into press contact with the plate cams
109
a
,
109
b
, respectively.
The index unit
101
drives a rotating shaft
102
into intermittent rotational motion. A rotary table
103
is attached to a lower end of the rotating shaft
102
. Up/down guides
117
which guide the up and down sliding movement of a plurality of pickup nozzle units
104
are fixed at equal intervals on the periphery of the rotary table
103
.
Each of the plurality of pickup nozzle units
104
comprises: a block
111
which is inserted in the up/down guide
117
so as to slide up and down; a pickup nozzle
113
inserted in the block
111
in the up/down direction and biased upward toward the block
111
by a spring
118
; and a cam follower
112
placed in a fixed-portion cam groove
106
and up/down-movable-portion cam grooves
107
a
,
107
b
which are provided in an up-and-down wavy shape over the entire circumference of the cylindrical cam
105
fixed to the support base
116
. The cam follower
112
is a roller as shown in FIG.
12
.
Next, detailed structure of the fixed-portion cam groove
106
and the up/down-movable-portion cam grooves
107
a
,
107
b
of the cylindrical cam
105
as well as operation of the cam follower
112
are described with reference to
FIGS. 8
to
11
.
Referring to
FIGS. 8
to
11
, the cylindrical cam
105
is fixed to outside of the rotating shaft
102
in a coaxial state with the rotating shaft
102
that performs intermittent rotational motion, as shown in
FIGS. 8 and 9
.
In the cylindrical cam
105
, as shown in
FIGS. 9
to
11
, the fixed-portion cam groove
106
as well as the up/down-movable-portion cam grooves
107
a
,
107
b
which intervene partly across the fixed-portion cam groove
106
are provided in an up-and-down wavy state over the entire circumference of the cylindrical cam
105
. The up/down-movable-portion cam grooves
107
a
,
107
b
are provided at specified positions on the circumference of the cylindrical cam
105
, i.e., at the locations of a component pickup station and a component mounting station where the pickup nozzle units
104
work. In
FIG. 8
, the up/down-movable-portion cam groove
107
a
is positioned at the location of the component mounting station where an electronic component is mounted onto a circuit board
115
, while the up/down-movable-portion cam groove
107
b
is positioned at the location of the component pickup station where a component is picked up from a component feed unit
114
.
Then, as shown in
FIG. 8
, upper ends of the up/down-movable-portion cam grooves
107
a
,
107
b
are connected to the levers
108
a
,
108
b
, respectively, and the up/down-movable-portion cam grooves
107
a
,
107
b
will be slid up and down by the levers
108
a
,
108
b
which are actuated up and down by the rotation of the plate cams
109
a
,
109
b
, respectively.
Within the fixed-portion cam groove
106
and the up/down-movable-portion cam grooves
107
a
,
107
b
, as shown in
FIGS. 8
to
11
, is placed the cam follower
112
. The cam follower
112
is integrally combined with the block
111
that is inserted in the up/down guide
117
so as to slide up and clown as described above. Therefore, when the rotation of the rotary table
103
causes the block
111
to go into intermittent rotational motion around the cylindrical cam
105
, the cam follower
112
moves up and down along the fixed-portion cam groove
106
and the up/down-movable-portion cam grooves
107
a
,
107
b
while rotating.
In this case, the plate cams
109
a
,
109
b
will rotate in synchronization with the intermittent rotational motion of the rotating shaft
102
and the rotary table
103
driven by the index unit
101
. However, the plate cams
109
a
,
109
b
have such a shape that the levers
108
a
,
108
b
will not be actuated during time durations when the cam follower
112
is within the fixed-portion cam groove
106
of the cylindrical cam
105
, and as shown in
FIG. 11
, the up/down-movable-portion cam grooves
107
a
,
107
b
will not be moved down until the cam follower
112
reaches the up/down-movable-portion cam grooves
107
a
,
107
b
of the cylindrical cam
105
. As the up/down-movable-portion cam grooves
107
a
,
107
b
move down, the cam follower
112
moves as shown by a cam follower track
119
indicated by two-dot chain line in FIG.
11
. While the rotating shaft
102
and the rotary table
103
are at an intermittent rest, the cam follower
112
reaches a lowermost position
119
a
as shown by the cam follower track
119
, at which lowermost position
119
a
the pickup nozzle
113
is made to perform an electronic component pickup operation or mounting operation. With this operation completed, as the rotating shaft
102
and the rotary table
103
start rotating, the plate cams
109
a
,
109
b
make the up/down-movable-portion cam grooves
107
a
,
107
b
move upward again, thereby rising them until the up/down-movable-portion cam grooves
107
a
,
107
b
coincide with the fixed-portion cam groove
106
of the cylindrical cam
105
.
With the above constitution, the operation time of component mounting operation can be reduced in the following way.
By the drive of the index unit
101
, the rotating shaft
102
and the rotary table
103
are caused to go into intermittent rotational motion, and the plurality of pickup nozzle units
104
attached to the periphery of the rotary table
103
are caused to start rotating. While the cam follower
112
is within the fixed-portion cam groove
106
of the cylindrical cam
105
, the plate cams
109
a
,
109
b
are equal in the diameter of operative portion to each other so that the levers
108
a
,
108
b
will not be actuated. However, as shown in
FIG. 11
, when the cam follower
112
has reached the portions of the cylindrical cam
105
corresponding to the up/down-movable-portion cam grooves
107
a
,
107
b
, the plate cams
109
a
,
109
b
have operative portions in troughs so that the levers
108
a
,
108
b
will be actuated, and the up/down-movable-portion cam grooves
107
a
,
107
b
will be lowered. During the rest time of the intermittent rotational motion of the index unit
101
, the up/down-movable-portion cam grooves
107
a
,
107
b
reach the lowermost position
119
a
, causing the pickup nozzle
113
to perform the electronic-component pickup or mounting operation. With this operation completed, as the rotating shaft
102
and the rotary table
103
start rotating, the up/down-movable-portion cam grooves
107
a
,
107
b
move
Hirai Wataru
Mogi Seiichi
Sakurai Kunio
Yamamoto Minoru
Matsushita Electric - Industrial Co., Ltd.
Tugbang A. Dexter
Wenderoth , Lind & Ponack, L.L.P.
Young Lee
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