Note: Descriptions are shown in the official language in which they were submitted.
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The present inven-tion relates to an eyeletting machine,
and more par-ticularly to a manually actuated fused eyele-tting
machine capable of cold and Eused setting of eyelets and
funnelets to printed circuit boards.
~CKGROUND OF T~IE IN~-ENTION
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The present invention constitlltes an improvement over
the fused eyeletting machines disclosed in IJnited States Patents
3,739,141; 3,940,590 and 4,584,460.
United States patent 3,739,141 discloses a fused
eyeletting machine having a C-shaped frame, with the upPer arm oE
the -frame housing an upper tool, and the lower arm housing a
resilient support structure for a lower tool which enables -the
eyelet setting pressure to be pre-determined. The upPer tool is
brought into contact with the lower -tool by means of a toggle
arrangement which is ~ivoted to the upPer arm oE the frame.
United States Paten-t 3,940,590 describes an improved
version of the machine disclosed in '141 patent. In the machine
described in the '590 patent, the upper arm of the C-shaped frame
terminates in a pair of spaced-apart tool support members, and a
double stop toggle mechanism is mounted between those support
members for actuating movement of the upper tool with respect to
the lower tool.
United States patent 4,584,4~0 describes a further
improved fused eyeletting machine which utilizes a novel and
simPlified support structure for resilien-tly biasing the lower
tool -to exert a pre-determined force
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against which the upper tool acts during the eyelet
setting operation. As Wit]l the machines described in
the '141 and '590 V.S. patents, the upper tool is
actuated by means of a toggle arrangement.
One of the disadvantages associated with the
structures described above arises from the use of a
toggle arrangement for actuating movement of one of
the tools towards and away from the other tool. In
those toggle arrangements, the s-tro~e length is fi~ed
so that difficulties in operation sometimes arise when
boards of different thicknesses or eyelets of different
lengths are utilized. These difficulties arise es-
pecially in the circuit board repair industry where
circuit boards and eyelets of various thicknesses and
lengths are encountered. In light of this, care must
be taken by the machine operator in each eyelet setting
operation to achieve the desired eyelet setting and
fusing on the board without crushing the board or dis-
torting the eyelets.
A further problem which arises from the use of
toggle actuating arrangements is that most toggle
mechanisms are manufactured according to low tolerance
specifications, so that difficulties are encountered
in achieving accurate and repeatable alignment of the
upper and lower tools each time the toggle arrange-
ment is used. This, in turn, gives rise to possible
dis-tortion of the eyelets as they are pressed into
contact with the board prior to fusing, which in turn
impairs the quality of the fused eyelet.
It is therefore a primary object of the present
invention to provide an improved eyeletting machine
capable of use with equal facility on eyelets and
funnelets of different sizes and on printed circuit
boards of different thicknesses.
It is another object of the present invention to
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provide an eyeletting machlne which utilizes a novel and
simplified tool moving arrangement whereby the eyelet
setting tools are brought into aligned contact with
each other at a pre-determined eyelet setting pressure,
which pressure can not be exceeaed despite continued
operation of the tool moving arrangement after the
pre-determined pressure has been reached.
SUI~l~ARY OF THE INVENTION
According to one aspect of the present invention,
there is provided a machine for setting eyelets and the
like, compr:ising a generally U-shaped frame having a
pair of spaced-apart support arms defining a work-piece
receiving zone therebetween. A first tool is movably
mounted in one of the support arms, and a second tool
is fixedly mounted in the other of the support arms so
that the second tool is axially opposed to the first
tool. A tool moving means is connected to the first
tool for moving the first tool into aligned contact
with the second tool at a pre--determined eyelet setting
pressure, with the tool moving means including an
adjustable torque limiting means for insuring that the
pre-determined eyelet setting pressure is not exceeded
upon continued operation of the tool moving means.
According to another aspect of the present
invention, there is provided a work-piece suspending
arrangement for vertically suspending the work-piece
into the work--piece receiving zone between the support
arm of the U~shaped frame. This arrangement enables
the work-piece to be suspended vertically next to the
first and second tools, and leaves the operator free
to finally position the work-piece relative to the
first and second tools while actuating the tool moving
means to bring the first tool into contact with the
eyelet to be fused in the work-piece.
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BRIEF DESCRIPTION OF THE DRAWINGS
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The invention will now be described in more detail
with reference to the accompanying drawings, in which:
Figure 1 is a side perspective view of the
machine of the present invention;
Figure 2 is a partial cross-sectional view taken
along the line 2-2 of Figure l;
Figure 3 is a partial cross-sectional view of an
alternative embodiment;
Figure 4 is an enlarged cross-sectional view of
a printed circuit board and an eyelet being set
therein.
DETAILED DESCRIPTION OF THE INVE~TION
Referring to Figure 1, there is shown a machine,
generally referenced 10, for setting eyelets and the
like in printed circuit boards. The machine 10 has a
U-shaped frame 12 which is suitably a cast frame. The
frame has a pair of spaced-apart support arms 14, 16
connected by a base section 18. The base section 18 is
preferably provided with feet members 20 which support
the frame, and also enable the machine to be secured
to a work table through apertures 22.
Mounted on the opposing support arms 14~ 16 of the
frame is a first tool 24 and a second tool 26. The
firs-t tool 24 is heid in a mandrel 28 which is movably
supported in a first tool support structure 30, and the
second tool 26 is fixedly mounted in a second tool
support structure 32. As shown in Figure 2, the upper
portion of the support arm 14 terminates in a pair of
spaced-apart tool support posts 34, 36. The support
post 34 houses the first tool support structure 30, and
the support post 36 supports an adjustable torque
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screw 38, which is described in more detail below.
Referring to the first tool support structure 30,
the mandrel 28 is slidably housed inside a cylindrical
support member 40 which, together with an annular
insulator ~ushing 42, is press fitted in a cy]indrical
aperture 44 in the support post 34. End 46 of the
mandrel 28 has a threaded portion 48 having thereon a
pair of nuts 50, 52, and an electrical cable 54 is
secured between the nuts. It will be seen, therefore,
that the principal purpose of the annular insulator
bushing 42 is to electrically insulate the cable 54
from post 34 and frame 12.
The adjustable torque screw 38, which is supported
in the support post 36, includes a shaft 56 having a
threaded portion 58 and an unthreaded portion 60. The
threaded portion 58 is threadably received in a threaded
aperture 62 in the post 36, and the threaded aperture 62
is positioned in post 36 such that the shaft 56 and the
mandxel 28 are axially aligned with each other, as shown
in Figure 2. The adjustable torque screw 38 has a
handle 64 with an adjustable torque mechanism 66 pro- -
vided internally of the handle, and rnay be of the type
supplied by Jergens, Inc. of Cleveland, Ohio, U.S.A.
The handle is fixedly mounted to the threaded portion 58,
so that rotation of the handle results in rotation of
the shaft 56. A swivel pad 60 is mounted on the remote
end of the unthreaded portion 60, and a stop clip 70
is mounted on the shaft 56 in a region of reduced
diameter between the unthreaded portion 60 and the
swivel pad 68. A piece of flexible plastic tubing 72
is stretch fitted over the swivel pad 68 and end 46 of
the mandrel 28 between nut 52 and stop clip 70 in order
to connect the mandrel 2g and the adjustable torque
screw 38 together. The significance of this connection
is discussed in more detail below. In order to further
insure complete insulation between the frame 12 and the
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electric cable 54, an insulating ring 76 is provided
between the nut 50 and the annular insulator bushing 42,
and an i.nsulating pad 78 is provided on section 80
extenaing between support posts 34 and 36.
As will be seen from Figure 2, the upper portion
of support arm 16 has an upstanding support member 82
with a cylindrical aperture 84 extending therethrough.
The second tool support structure 32 includes a support
mandrel 84 which fixedly houses the second tool 26 at
one end 86. End-94 of the support mandrel 84 is
threaded and is provided with a pair of nuts 88 and 90
with an electric cable clamped therebetween.The support
mandrel 84 is received in a cylindrical insulator
bushing 96 wliich is press fitted in a cylindrical
aperture 98 in the upstanding support member 82. A
portion of enlarged diameter 100 is provided on the
support mandrel 84 which abuts against the insulator
bushing 96 so that the support mandrel 84 can be
firmly mounted in the cylindrical insulator bushing 96
upon tightening of the nuts 88, 90. A support plate
102 may be provided as shown in Figure 2 to provide
additional support for the second tool support
structure 32.
Figures 1 and 2 also show a work-piece suspending
arrangement 104 which consists essentially of an L-shaped
member 106 and an adjusting arm 108 which telescopingly
receivable within the L-shaped member 106. As shown
in Figure 1, a support means, for example a clip 110, '-
is provided on the end of the adjusting arm 108 for
vertically suspending a work-piece 112, typically a
circuit board, into the region between the support
arms 14, 16 and close to the first and second tools
24, 26. Positioning of the circult board 112 is
accomplished by telescopingly moving the adjusting
arm 108 inside the L-shaped member, and when the
desired position has been reached, the adjusting al~ 108
can be fixed in that position by means of screw member
114. As illustrated, the suspending arrangernent 104 is
mounted on the support post 34, but could also be
mounted elsewhere on the machine, for example, on the
upstanding support member 82. In addition, the suspending
arrangement 104 may be mounted i.n the support post 34 so
that it can be rotated about the axis of the vertical
upstanding portion 107 of the L-shaped member to
facili-tate swinging the circuit board 112 into and out
of the work-piece receiving zone between the support
arms 14, 16.
In Figure 3, -there is illustrated an alternative
embodiment in which a stripper accessory 116 is provided
on the end of the second tool 26. The stripper accessory
116 comprises a plastic annulus 118 with a flat upper
surface therein and a helical spring 120 secured to the
plastic annulus 118. The stripper accessory 116 fits
around the second tool 26 as shown in Figure 3 with its
flat upper surface flush with the tip end of the
second tool 26 and the helical spring 120 resting
adjacent the top of the support mandrel 84. The purpose
of the stripper accessory 116 is to square a work-piece
on the second tool 26 so that the eyelet, funnelet, or
the like, may be properly aligned on the work-piece
prior to being contacted by the first tool 24. During
the setting operation, the stripper accessory 116 is
- forced along the second tool 26, and-it is to be noted
that the presence of the stripper accessory 116 does
not affect actual operation of the tool 24, 26. The
stripper accessory 116 may be removed if insufficient
space is present on the work-piece.
Operation of the machine of the present invention
will now be aescribed with reference to Figure 4 of
the arawings.
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In Figure 4, a work-piece such as a prlnted circuit
board 112 is shown having an eyelet hole 122. A pre-
inserted eyelet or funnelet 124 is loosely positi.oned
in hole 122 with its pre-formed head 126 facing towards
tool 24. The work-piece 112 and the eyelet 124 are
moved to a position between the first and second tools
24, 26, suitably by suspending the work-piece from
the clip 110 as shown in Figure 1. The work-piece 112
is located such that the eyelet 124 is positioned
10 adjacent the second tool 26, and the first tool 24 is
advanced towards the pre-formed head 126 of the eyelet
124 by urging the adjustable torque screw 38 from right
to left from position W as seen in Figure 2 to bring
threaded portion 58 into threaded engagement with the
threaded aperture 62, followed by rotating the adjustable
torque screw 38 to screw the threaded portion 58 into
the threaded aperture 62 and thereby advance the
second tool 24 into engagement with eyelet 124. The
adjustable torque screw 38 is pre-adjusted to the
desired torque limit, which i.s typically 20 to 60 lbs,
for example 32 to 40 lbs, usually about 35 lbs, and
rotation of the hand]e 64 is continued until the torque
limit is reached and the desired eyeletting pressure is
achieved. As the desired eyeletting pressure is reached,
upsetting and cold setting of the eyelet 124 occur so
that the. eyelet is just tight enough not to rotate in
hole 122, and the eyelet or funnelet is then fused to
pad 128.on the printed circuit board 112 by electrically
generated heat. The sizes of the first and second tools
24, 26 may be varied according to the different sizes
of eyelets or funnelets utilized.
When fusing of the eyelet or funnelet 124 has been
completed, the first tool 24 is withdrawn from contact
with the fused eyelet by rotating the handle 64 in order
to unscrew the threaded portion 58 rom the threaded
aperture 62 and pull the first tool 24 and the mandrel 28
32
g
from left to right as seen in Figure 2 as a result of
the connection between the manclrel 28 and the adjustable
torque screw 38 by the flexibl.e plastic tubing 72.
~otation of the handle 64 to unscrew the threaded
portion 58 from the threaded aperture 62 gives rise
to a relatively slow withdrawal of the first tool 24
from the work-piece 112, but this withdrawal may be
increased when the threaded portion 58 becomes dis-
engaged from the threaded aperture 62 so that the
torque screw 38 together with the mandrel 23 oftool 24
can be manually pulled to position W. When position W
is reached, the s-top clip 70 comes into abutting engage-
ment with the face 130 of the tool support post 36 in
order -to avoid further withdrawal and possible dis-
engagement of the screw 38 from the machine 10. If
desired, a spring (not shown) may be placed between face
74 and handle 64 to assist in the movement of the
adjustable torque screw 38 towards position W after dis-
engagement from threaded aperture 62.
If it is desired to conduct a further eyelet
fusing operation, the work-piece with the inserted eye-
let is arranged with respect to the second tool 26,
advantageously by suspending from a suspending arrange-
ment 104 as described above, and the first tool 24 is
advanced into contact with the eyelet by urging the
torque screw 38 from right to left as shown in Figure 2
from position W in order to effect threaded engagement
of the threaded portion 58 with the threaded aperture 62.
The handle 64 is then rotated to effect gradual advance-
ment of the first -tool 24 into contact with the eyelet.
In this regard, it will be noted -that the flexible
plastic tubing 72 is sized such that the end 46 of the
mandrel 28 and the swivel pad 68 remain coupled when
the torque screw 38 is pulled towards position W. When
-~he torque screw 38 is rotated in order to advance the
first tool 24 towards the second tool 26, the shaft 56
rotates, but the swivel pad 68 does not rotate in view
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of the swivel pad connection 132, so that rotation of
the torque screw 38 does not result in the first tool 24
being rotated as it advances towards the work-piece.
It will be appreciated from the above that the
machine of the present invention enjoys numerous
advantages over prior eyelettin~ machines. In particular,
the present machine utilizes a torque screw arrange-
mentinstead of a toggle arrangernent for moving the
first tool towards or away from the second tool, and this
enables the machine to be used for eyelet fusing
operations using eyelets of different lengths and/or
circuit boards of difEerent thicknesses. In addition,
the eyelet setting pressure can be set to a pre-
determined value with the adjustable torque screw
arrangement so that an accurate repeatable eyelet
setting pressure can be applied and crushing of the
board or distortion of the eyelet is substantially
eliminated. Furthermore, by using the adjustable
torque screw arrangement of the present invention,
the accuracy of the axial alignment of the first and
second tools is substantially improved over that which
is generally achievable. In addition, the torque screw
arrangement of the present application occupies less
space thereby enabling the machine to be housed in a
compact unit. A further advantage arises from the fact
that the second tool is fixedly mounted in the support
arm 16, so that it is not necessary to incorporate any
biasing mechanism -to achieve the desired eyelet setting
pressure. As discussed earlier, the eyelet setting
pressure is controlled entirely by the first tool
moving arrangement which incorporates the adjustable
screw device, and this results ;n a more convenient
and less costly machine.
