Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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PLACEMENT MECHANISM
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Thls inventiorl relates to a meehanism for pieking up
and placing on a substrate small artleles sueh as miero-
elec-tronic componen-ts.
In the processing of micro-eleetronie eomponents (chips),
the component is obtained from a supply source and trans-
ported to a plaeement head having a placement mecharlism which
pieks up the eomponent and places it on a printed circuit
board. In eommonly owned U.S. Patent No. 4,501,064 issued
February 26, 1985 sueh a component proeessing appara-tus is
disclosed. Also disclosed in eommonly owned Canadian patent
applica-tion Serial No. 469,748 filed Deeember 10, 1984 there
is a mechanism for adjusting the position of the plaeemen-t
head for different sized eomponents. In both of the above
disclosures, -the placement head performs a motion on a
vertical axis Erom the position of reeeiving the component
to positioning the eomponent on -the printed cireuit board.
There are maehines for automa-tieally obtaining ehip
si~e eomponents from a supply souree and transporting the
component to a placement head which positions -the eomponent
on a printed cireuit board. Examples of these maehines are
illustrated in U.S. Patent Nos. 4,307,832; 4,327,482;
4,346,514 and 4,393,579. None of these maehines have a
plaeement meehanism with a vertieal motion on a single
axis during which the mechanism pieks up the component and
moves the eomponent down to the board for positioning
between the conduetive lands of -the eireuit on the board.
Further, the plaeement mechanisms are not rotationally
positionable on the same axis -to align the eomponent with
the eireuit on -the board.
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RIEF ~ RY OF THE IN~ rION
It is the purpose of this invention to provide a placement
mechani~m that is vertically displaced to receive a micro-electronic
component and place the cc~onent between the conductive lands on a
printed circuit board.
It is also an object of this in~ention to provide a place~.ent
mech~nism which can be moved on a single axis vertically from a
position to receive a co~ponent and place the co~ponent on a board
and also be rotated on the sane verticaI axis to align the leads of
the component with the conductive lands of the circuit on the board.
It is a further object of this inventiorl to provide in a
placement mecharlism a housing adapted to be posltioned above an
article conveyor for receiving an article from the conveyor and
placing the same on a substrate. A spindle is m~unted in the
housing for up and down movement on a verticle axis and is adapted
to rotate on that axis to properly align the article with
preselected portions of the substrate. A plac~ment rod is mounted
in the spindle and has a tip for receiving and holding the article.
There is a resilient interconnection between the spindle and the
placement rod to buffer the i~pact o~ the plac~ment of the article
on the substrate and to acconmodate variable thicknesses in the
substrate. A resilient part of the tip also buffers the i~pact of
the placenPnt Or the component on the board~ The rod ~d tip have a
central opening which when subjected to a vacuum will retain the
article on the tip and when subjected to an air blast wi]l release
the article from the tip onto the substrate.
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STATEMENT OF INVENTION
According to a still further broad aspect of the present
invention -there is provided a placement mechanism for orient-
ing and positioning an electrical component on a substrate.
The mechanism comprises a housing adapted to be supported
above the substrate and includes a cylindrical opening. A
spindle is rotatably mounted in -the opening about a vertical
axis. The spindle has a lower end portion slidably receiving
a placement rod that receives a component, and places the
component on the substrate. A piston surrounds the spindle
and is carried in the opening and movable in response to a
fluid medium -to move -the spindle toward and away from the
substrate along the ver-tical axis. Means interconnects the
spin~le and the rod. This interconnecting means comprises a
collar on the sp:Lndle and set screws threaded into the
collar. The set screws are engageable with flat sides on
the rod to maintain the spindle and the rod in axial align-
ment. The collar is adjustably threaded onto the spidle ~o
permit vertical adjustment Qf the rod relative to the spindle
along the vertical axis. Means is provided to resiliently
interconnect the spindle and the rod to cushion impact of
the placement of the component-onto khe subs-trate and accom-
modate substrates of different thickness. Means is also
provided for rotating -the spindle and the rod to orient the
component prior to its being positioned on the substrate.
BRIEF DECRIPTION OF THE DRAWINGS
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Figure 1 is a side elevational view oE the
placemerlt head;
Figure 2 is a sectional view of the placement
mechanism of this invention; and
Figure 3 is an exploded view of the placement
mechanlsm of this invention.
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DESCRIPTION OF THE PREFERRED EMBODIMENT
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The micro-electronic component assembly machine in which
the placemen-t mechanism of this inventi.on is utili~ed in the
type disclosed in commonly owned U.S. Patent No. 4,501,064
which issued on February 26, 1985. That component assembly
machine utilizes an air conveyor to transport a cornponent
from a s~pply source to apparatus receiving the component
beneath the placemerlt head which positions the component on
the board. In that disclosure and the disclosure of
commonly owned Canadian Patent Appiication Serial No.
469,748 filed on December 10, 1984, the component receiving
means is adjustable in position to accommodate various sizes
of components to center the component in the placement head
to assure the component leads are placed on -the conduc-tive
lands of the circuit on the board. The disclosures of both
-the aforementioned prior applications are incorporated here:in
by reference.
In the componerlt placement machine illus-trated, a place-
ment head 8 comprises an air conveyor 10 which transports the
component (c) from a supply source (not shown) to a receiving
means 12 positioned below the placement mechanism 14. The
receiving means 12 comprises an adjustable shelf 16 posi-
tioned by a piston 18 in a cylinder 20. The air in line 22
will move the piston 18 to position the shelf 16 inward
underneath the placement mechanism 14 so that the component
(c) in the shelf 16 can be picked up by the placement
mechanism 14. Thereafter, air in line 24 will move the
piston 18 to the right to move the shelf 16 outward to permit
the placement.mechanism to move toward the board (not shown)
to place the component on the board. A stop mechanism 26
~ontrols the rearward movement of the piston 1~ to control
the position of the shelf 16 underneath the placement
mechanism.
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1 ~e placement mechanism 14 is carried in a housing 28 supported
on the machine support (not shown). The housing 28 has a stepped
bore 30 having an upper portic)n 32 and a lower portion 34. A
spindle 36 is carried in the bore 30 an~ has a lower opening 38
car~ying a placement ro~ 40. The placen~nt rod 40 has an upper area
42 received within the opening 38 and a lower area 44 into which a
tip or nozzle 46 is threaded at 48. An opening 50 passes through
the placemen~ rod 40 and communicates with the interior of opening
38. A vacul~ line 52 is attached at 54 to the lower bore 34 and
provides va~uun to the nozzle 46 through openings 56 in the spindle
36. A seal 58 surrounds the end 60 of placem~,nt rod 40. The rod 40
is norn~lly bia,sed downward by a spring 62 positioned bet~veen the
end 6~ of opening 3$ ~md a plug 66. A collnr 68 is threaded around
the end 70 of the spindle 36 and has set screws 72, 74 which ride
against the flattened ides 76, 78 of the placement rod 40 to
prevent rotation of the placement rod 40 in the spindle 36 for
reasons that will bec~ne appflrent hereafter. The position of the
collar 68 on the spindle 36 will adjust the spacin~ of the tip 46
from the shelf 16. The collar 58 is locked on spindle 36 by lock
nut B9 to vertically position the tip 46 from the shelf 16. A
bearing gland 80 and seal 82 nre positioned around the spindle 36 to
seal the lower bore 34 and provide thè lower bearing surface for the
spindle 36. An additional seal 83 surrounds the spindle 36. In the
operation of the placement mechani~n thus far described, vacuwn in
the placement rod will retain a cor.ponent on the nozzle 4G. A~ a
co~ponent is placed on the board, the spring 62 acting against the
end of the placement rod 40 through plug 66 and will allow for
~arying board heights and buffer the i~pact of the placen~nt of the
cc~ponent on the board.
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1 Attentio~ is now directed to ~igures 1 and 2 which illustrate
the portion of the placemellt mechanisn ~Jhich lowers the placement
rod 40 so that after a component is removed fra~ the shelf 16, the
component can be lowered to a position on the board. kn insert 84
~- 5 and seal 86 are located in the upper bore 32 to isolate the upperand lower portions of bore 30. ~n additional seal 87 surrounds the
spindle 36. Positioned against the shoulder 88 of spindle 36 is a
piston 90. The piston 90 is retained o~l the spindle 36 by a nut 92.
A resilient bu~,per 94 ~surrounds the spindle 36 between the piston 90
and the insert 84 to soften the impact of the piston 90 against the
: insert 84.
I~e top 96 of the upper bore 32 in the housing 28 is enclosed
by fl cap asse~ly 98 which permits the spindlc 36 to be n~vecl ~ ~d
down in the housing d~ring the placement of the component on the
board. The cap assembly 98 also permits the spindle 36 to be
rotated so that the leads of the component (C) curried on noz~le 46
can be aligned with the lands of the circuit on the boa~d.
The cap assexbly 98 comprises a cup 100 having a bott~n portion
102 extending into the top 96 of the up~er bore 32. An annular
: 20 groove 104 surrounds the bott~m portion 102 and contains a seal 106,
to seal the bore 32. The spindle 36 is mounted through fl bearing 111
and a seal 110 in the opening 112 in the bott~ portion 102 of the
cap assembly 98. The seal 110 is retained in opening 112 by a snap
rin~ 114. The botton portion 102 also has a recess llG to
25~ acco~modate the nut 92 when the piston 90 is in the upper position.
A bumper 108 surrounds the bottom portion 1~2 to soften the i~pact
~ ~ of the piston 90 againæt the cap ass3Tbly 98.
: ~ A collar 118 is mounted in bearings 120, 122 which are
separated by ~ spacer 124. A cap 126 is positioned between the
béaring 120 and a pulley 128 intregal with the collar 118. A snap
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1 ring 132 in annular groove 134 retains the bearings 120, 122 and
spacer 124 on collar 118. Cap 126 is attached through cup 100 to
housing 28 with screws 150. A spring washer 136 is positioned
between the bearing 120 and the cap 126 in recess 138 to preload
bearings 120, 122 for the purpose of remo~ing bearin~ clearanee
which will give collar 118 a m~ore precise ~nd stable rotating
motion.
A square rod 140 is positioned in the opening 142 in collar 118
and rests on the shoulder 144 on the spindle 360 An extensi~n 146
is threaded onto the end 148 of spindle 36 and secures the rod 140
to the spindle. The sclllare opening 142 in the collar 118 through
which the ro~ 140 is posit~oned pernits the pulley 128 to rotatc the
spindle 3fi while the spindle is reciprocnting. Ihe pulley 128 is
driven by a belt 152 carried on a drive pulley 154 of motor 156.
Ihe motor 1~6, in response to progra~med control, rotates the
spindle 36 and thus placement rod 40 to ~lign the corponent held on
the end of the plac~ment rod with the desired locatic~n on the board.
The cap 126 and cap assembly 98 are assembled to the housing 28
~y screws 150. In the assen~led condition ~Fig. 2) the bearing 122
Z rests against the shculder 158 in opening 160 of the CUp 100.
In operntion, after the vacutnn tip 46 picks the cc~ponent fron
the shelf 16 ancl the shelf 16 mo~es forward, air in line 164 will
Ic~er the pistOlt 90 an~ thus spindle 3~ to pe~mit the plac~ment rod
to lower the cc~onent onto the printed circuit board. ~ith the
resilient interconnection between the spindle and placement rod
varying thicl~ess of the substrate are accc~moclated.
Since there is a cle~rance 165 arot~d the spindle 36 in the
lower bore 3~t the vacut~n will continue to hold the component on the
nozzle 46. Also, at the tin~ the cc~ponent reaches the board, the
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1 vacu~n in line 52 will be relieved and an air blast in line 52 will
release the component frc~ the tip or no~zle ~6 onto the board.
Thereafter, air in line 162 will raise the spindle 36 uncl the
shelf 16 will move inward to receive another comp~nent so that the
tip 46 can pick another cc~ponent frcm shelf 16. Further, during
this place~ent sequence, the rotational m~unting of the spin~le
pe~mits the co~ponent to be aligned to assure that the component
leads are properly placed on the lands of the circuit on the board.
The extension 146 on spindle 36 COflCtS with the switches 166 on
the housing 28 to give an indication of the positiorl of the spindle
36.
Attention ls also directecl to the fnct that the nozzle 4fi has R
reccss or groove 17~1 in-to which the chip type corrponent nests. The
gYoove 170 has an energy absor~ing material 172 to help bwffer the
impact of the placenent of the co~ponent on the boarcl. F~lrtherj the
co~onent iæ held between the sides 174, 176 of the groove 170 when
the spindle 36 is rotated during the aligr~ent o~ the co~ponent with
the circuit on the board.
It caIl thus be seen with the use of a spindle rotatably mounted
in the placem~nt head housing and movable toward and away from the
board, a cc~onent can be properly aligned with the circuit and
easily ancl accurately placed on the board. FurtherJ with the
placement rod slidably mounted in the spindle, the cc~ponent can be
placed OTI uneven bvard surfaces with no damage to the co~ponent.
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