U.S. patent number 3,837,063 [Application Number 05/368,448] was granted by the patent office on 1974-09-24 for post terminal insertion apparatus.
This patent grant is currently assigned to Elco Corporation. Invention is credited to Robert Charles Wright.
United States Patent |
3,837,063 |
Wright |
September 24, 1974 |
POST TERMINAL INSERTION APPARATUS
Abstract
Apparatus for direct insertion into a substrate of terminals
from a flexible carrier strip releasably supporting the terminals.
The strip path of travel toward a terminal removal zone and from
that zone is constrained to accomodate strip flexibility and travel
without binding while preventing significant strip twisting and
transverse and lateral excursion. A guide block assembly
establishes that path of travel in first and second channel guide
sections where the terminals and deflected strip portions are
respectively guided by flanges. During terminal removal, resilient
jaws aid in providing uniform deflection of these strip portions.
Continuous tension tends to advance the strip, and escapement
fingers control strip indexing. A ram assembly, operable after
indexing to directly insert the terminal, includes selected
gripping inserts cooperable with differently sized terminals. An
anvil assembly cooperates with a sensor and an indicator to insure
correct substrate orientation relative to the ram assembly.
Inventors: |
Wright; Robert Charles
(Huntingdon Valley, PA) |
Assignee: |
Elco Corporation (Willow Grove,
PA)
|
Family
ID: |
23451239 |
Appl.
No.: |
05/368,448 |
Filed: |
June 8, 1973 |
Current U.S.
Class: |
227/2; 29/739;
29/707; 29/721 |
Current CPC
Class: |
H05K
13/04 (20130101); Y10T 29/5303 (20150115); Y10T
29/53091 (20150115); Y10T 29/53174 (20150115) |
Current International
Class: |
H05K
13/04 (20060101); H05k 013/04 () |
Field of
Search: |
;29/23B,23P,211R,625 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Eager; Thomas H.
Attorney, Agent or Firm: Burns, Doane, Swecker &
Mathis
Claims
What is claimed is:
1. Apparatus for establishing a path of travel for a flexible
carrier strip releasably mounting a plurality of terminals,
generally orthogonally to the direction of strip extent, for
removal and insertion into a substrate by ram means, the apparatus
comprising:
guide channel wall means for establishing an elongate guide channel
through which the strip may be threaded;
ram path wall means defining a ram movement zone for accomodating
movement of ram means transversely of said guide channel into
engagement with terminals carried by the strip;
said guide channel wall means being operable to constrain the
carrier strip and supported terminals against significant twisting
and significant excursion laterally and transversely of the extent
of the strip threaded in said guide channel, while providing
clearance to accomodate strip flexibility and relatively free strip
advancement through said guide channel, and including:
first channel forming surface means, guidingly cooperable with
releasably strip supported terminals in the first section of said
guide channel leading to said ram means movement zone, to limit
relative movement between the terminals and the strip laterally of
the extent of the strip, and
second channel forming surface means for guidingly cooperating, in
a second section of said guide channel leading from said ram
movement zone, with terminal support portions of the strip from
which terminals have been removed.
2. Apparatus according to claim 1 wherein the terminal support
portions of the strip are deflectable by ram means during terminal
removal, and wherein:
said second channel forming surface means is engagable with
deflected terminal support portions of the strip.
3. Apparatus according to claim 2 including:
terminal insertion back-up jaw means having jaw portions mounted
for pivotal movement toward and away from said ram movement zone;
and
resilient means for biasing said jaw means toward said ram movement
zone;
said biased jaw means being operable to engage terminals releasably
carried by the strip during engagement of ram means with the
terminals to substantially uniformly control deflection of said
deflectable support portions of the strip.
4. Apparatus according to claim 2 wherein:
said second channel forming surface means includes cam means
adjacent said ram movement zone and cooperable with deflected
support portions of the strip to cam such portions into a generally
uniform orientation in the section of said guide channel leading
from the ram movement zone.
5. Apparatus according to claim 1 including:
feed means operable to apply continuous tension to the strip urging
the strip in an advancing direction through said guide channel;
escapement means for controlling advancement of the carrier strip
through said guide channel, said escapement means including:
first escapement finger means engageable with the strip in said
first guide channel section,
second escapement finger means engageable with the strip in said
second guide channel section; and
escapement finger control means for establishing alternate
engagement of said first and second escapement finger means with
said strip.
6. A guide block assembly for establishing a path of travel for a
terminal carrier strip, said strip being comprised of a flexible
elongate member of generally U-shaped cross-section defined by a
base and contiguous legs having support portions deflectable by ram
means operable to remove terminals from the strip and directly
insert them into a substrate, said support portions of said legs
releasably mounting a plurality of terminals generally orthogonally
to the direction of strip extent, with the terminals extending
between and projecting beyond both legs, said guide block assembly
comprising:
wall means defining a ram means movement zone for accomodating
movement of ram means into engagement with terminals carried by
said strip;
first guide channel wall means defining a first guide channel
section;
second guide channel wall means defining a second guide channel
section;
said first and second guide channel section being generally aligned
to establish an elongate guide channel through which the strip may
be threaded, with said guide channel intersecting said ram means
movement zone to provide a terminal removal and insertion zone
intermediate said first and second guide channel sections; said
first guide channel wall means including:
a first recess having first recess guide surface means for
guidingly cooperating with the base of the carrier strip and with
external portions of the carrier strip legs along their extent from
that base to the terminals,
a first guide flange projecting toward said first recess and having
first guide flange surface means for guidingly cooperating with the
internal portions of the carrier strip legs along their extent
projecting beyond the terminals and with an extent of the terminals
between the carrier strip legs, and
guide rail means extending along said first recess for guidingly
cooperating with projecting portions of the terminals extending
from the carrier strip legs;
said second guide channel wall means including:
a second recess having second recess guide surface means for
guidingly cooperating with the base of the carrier strip and with
deflected portions of one of the strip legs adjacent its juncture
with that base, while deflected portions of the other strip leg
remain essentially free from guidance, and
a second guide flange projecting toward said second recess and
having second guide flange surface means for guidingly cooperating
with the said deflected portions of said one of the strip legs;
said guide rail means, said first and second recess guide surface
means, and said first and second guide flange surface means being
operable to constrain the carrier strip and supported terminals
against significant twisting and significant excursion laterally
and transversely of the extent of the strip threaded in said guide
channel, while providing clearance accomodating flexibility of the
strip and limiting binding during travel thereof.
7. A guide block assembly according to claim 6 including:
terminal insertion back-up jaw means having jaw portions mounted
for pivotal movement toward and away from said ram movement zone;
and
resilient means for biasing said jaw means toward said ram movement
zone;
said biased jaw means being operable to engage terminals releasably
carried by the strip during engagement of the ram means with the
terminals to substantially uniformly control deflection of said
deflectable portions of the strip.
8. Apparatus according to claim 7 wherein:
said jaw portions include mutually inclined, terminal aligning
faces.
9. Apparatus according to claim 6 wherein:
said second guide flange surface means includes inclined cam means,
adjacent said terminal removal and insertion zone and cooperable
with deflected portions of the strip legs, to cam such portions to
the level of the remaining portion of said second guide flange
surface means.
10. Apparatus according to claim 6 including:
escapement means for controlling advancement of the carrier strip
through said guide channel, said escapement means including:
first escapement finger means engageable with the strip in said
first guide channel section,
second escapement finger means engageable with the strip in said
second guide channel section; and
escapement finger control means for establishing alternate
engagement of said first and second escapement finger means with
said strip.
11. Apparatus according to claim 10 wherein said escapement finger
control means comprises:
escapement spring means for biasing said second escapement finger
means out of engagement with the strip;
solenoid means, operable in an energized condition to move said
first escapement finger means out of engagement with the strip, and
operable in a de-energized condition to permit movement of said
first escapement finger means into engagement with the strip;
and
finger linkage means operable, in response to movement of said
first escapement finger means out of engagement with the strip upon
energizing of said solenoid means, to move said second escapement
finger means into engagement with the strip against the bias of
said escapement spring means, and operable, in response to movement
of said second escapement finger means out of engagement with the
strip upon de-energizing of said solenoid means, to move said first
escapement finger means into engagement with the strip.
12. Application according to claim 11 including:
feed means operable to apply continuous tension to the strip urging
the strip in an advancing direction through said guide channel.
13. Apparatus according to claim 6 including:
ram means operable to remove terminals from the strip and directly
insert them into a substrate;
said ram means including ram arm means movable in said ram means
movement zone and engageable with terminals for removal and
insertion,
said ram arm means comprising:
a body section, and
a nose section,
said nose section including a terminal receiving opening defined by
means, including a removable resilient insert, for resiliently
gripping a received terminal and limiting the depth of reception of
the terminal in said terminal receiving opening.
14. Apparatus according to claim 13 wherein said guide block
assembly includes:
terminal insertion back-up jaw means having jaw portions mounted
for pivotal movement toward and away from said ram movement zone;
and
resilient means for biasing said jaw means toward said ram movement
zone;
said biased jaw means being operable to engage terminals releasably
carried by the strip, during engagement of said ram arm means with
the terminals, to urge the terminals into said terminal receiving
opening of said nose section.
15. Apparatus according to claim 6 including:
ram means operable to remove terminals from the strip and directly
insert them into a substrate;
an anvil assembly aligned with said ram means and cooperable with
the substrate and said ram means to effect terminal insertion, said
anvil assembly including:
tubular housing means including a receiving opening for receiving a
portion of an inserted terminal projecting below the substrate,
locating finger means movably mounted in the receiving opening of
said housing means,
anvil spring means for biasing said locating finger means to
project from said receiving opening of said housing means,
said locating finger means being sized for reception by a terminal
receiving aperture of the substrate; and
sensing means operable in response to displacement of said locating
finger means from its projected position to disable activation of
said ram means.
16. Apparatus according to claim 15 including:
light source means for directing light toward said locating finger
means to provide a visual indication of reception of said locating
finger means by a terminal receiving aperture of the substrate.
17. Apparatus according to claim 6 including:
a manually positionable jig means for orienting a substrate in
alignment with said ram means movement zone, said jig means
comprising:
a plurality of substrate support bars,
track means movably mounting said substrate support bars to adjust
their spacing,
clamp means for clamping the substrate to said support bars,
and
first and second movable switch control means disposed at opposite
ends of said track means, and operable only upon movement of both
of said switch control means to effect actuation of a ram
means.
18. A guide block assembly for establishing a path of travel for a
terminal carrier strip, said strip being comprised of a flexible
elongate member having support portions deflectable by ram means
operable to remove terminals from the strip and directly insert
them into a substrate, said support portions of said strip
releasably mounting a plurality of terminals generally orthogonally
to the direction of strip extent, with the terminals extending
between and projecting beyond said support portions, said guide
block assembly comprising:
wall means defining a ram means movement zone for accomodating
movement of ram means into engagement with terminals carried by
said strip;
first guide channel wall means defining a first guide channel
section;
second guide channel wall means defining a second guide channel
section;
said first and second guide channel section being generally aligned
to establish an elongate guide channel through which the strip may
be threaded, with said guide channel intersecting said ram means
movement zone to provide a terminal removal and insertion zone
intermediate said first and second guide channel sections;
said first guide channel wall means including first guide flange
surface means for guidingly cooperating with an extent of the
terminals between the carrier strip support portions; and
said second guide channel wall means including second guide flange
surface means for guidingly cooperating with deflected support
portions of the carrier strip.
19. Apparatus according to claim 18 including:
feed means operable to apply continuous tension to the strip urging
the strip in an advancing direction through said guide channel;
and
escapement means for controlling advancement of the carrier strip
through said guide channel, while permitting transmission of
tension throughout said strip in said second guide channel section
and said terminal removal zone.
20. Apparatus according to claim 19 including:
resiliently biased jaw means operable to engage terminals during
removal and to substantially uniformly control deflection of the
support portions of the strip.
Description
BACKGROUND OF THE INVENTION
This invention relates to apparatus for installing elongate objects
such as pin or post terminals on substrates such as printed circuit
boards. More particularly, this invention relates to apparatus
wherein pins discrete from and removably carried by a flexible
plastic carrier strip are directly inserted into a circuit
board.
A polyester carrier strip of this type is disclosed in a commonly
assigned copending patent application Ser. No. 288,851, filed Sept.
13, 1972, for "Pin Terminal Carrier Strip." The strip is comprised
of an elongate member having a generally U-shaped transverse cross
election. The opposite legs of the U-shaped member are provided
with aligned carrier slots for holding pins in a generally
orthogonal relationship to the strip. Relief slots are also
provided in these legs to facilitate transport of the strip by
sprocket wheels or the like, while the pins remain seated in the
carrier slots. For such transport purposes, the base of the
U-shaped member includes indexing apertures cooperable with the
sprocket wheels.
In the above-mentioned application, the disclosure of which is
hereby incorporated by reference, the carrier strip previously
described is discussed in the context of overcoming drawbacks
associated with prior pin installation techniques.
One such prior technique is that of manual, individualized
installation. This type installation not only is time consuming by
reason of the large numbers of pins usually involved and their
handling difficulty attributable to size, but also may not be
entirely satisfactory from the standpoint of obtaining reliable pin
orientation perpendicular to a board without pin damage.
Although some of the problems associated with manual installation
may be overcome through prior proposals for automated handling of
loose pins with a vibrating hopper or similar arrangement for
orienting the pins, it will be appreciated that significant room
for improvement exists. Particularly, several drawbacks may be
encountered with such arrangements in the areas of the speed of
operation, complexities in relation to pin handling once the pins
are oriented, etc.
As pointed out in the previously identified application, there have
also been prior proposals directed toward providing carrier strips
for pin terminals and other types of contacts. However, such
proposals may not be entirely acceptable for a variety of
reasons.
For example, in some cases heat is required for contact removal.
Often the flexibility of the carrier strip is not particularly
suited for adequate handling in an automated manner. Disposal costs
in connection with some strips made from certain materials may be
prohibitive. In addition, complex equipment is often contemplated
for removal of the contacts from strips with which the contacts may
be integral.
The flexible, easily handled carrier strip of the aforementioned
application is intended to aid in overcoming problems of the sort
previously noted. In accordance with the teachings of that
application, removal of the pins from that strip may be
accomplished by applying a force to the pin either in a direction
transverse to the extent of the strip or in an axial direction.
With transverse removal, equipment in addition to that used for
removal is required for insertion of the pins. With axial removal,
a post employed for pin removal may also be used for direct pin
insertion. During direct insertion of the pin, the yieldable legs
of the U-shaped strip are displaced by the recessed post which
embraces the pin and axially translates it into a position of press
fit reception in a circuit board hole.
The present invention relates to direct pin insertion of this type.
Specifically, the present invention is concerned with retaining the
advantages of single stroke pin removal and installation as
disclosed in the above noted application, while minimizing or
obviating problems associated with such a direct insertion
technique.
In this connection, it will be recognized that among the
difficulties that might be encountered with automated pin insertion
techniques is that of insuring reliably reproducible location of
the pins at a pin insertion zone aligned with the circuit board
hole to receive the pin. Although the flexibility of a pin carrier
strip enhances its handling and transport characteristics, that
same flexibility might contribute to misalignment of the pins at
the insertion zone, both as an initial matter and during pin
insertion. Similarly, where direct insertion is attempted,
misalignment problems might result from inadequate provision for
carrier strip advancement.
Problems such as these can be somewhat remedied by using equipment
separate from the carrier to grip and orient the pins at the
insertion zone. However, provision of such equipment could give
rise to potentially higher equipment costs and lower operational
speeds. Conversely, elimination of such equipment could create
other difficulties associated with force and positional
relationships between the pin and the members acting on the pin
during insertion.
One previous machine of the present assignee, not of the direct
insertion type, utilized removal equipment to transversely remove
the pins from a carrier strip. This equipment also aided in
insuring correct positioning of the pins for insertion. It would,
however, be desirable to eliminate the need for such equipment by
reason of the earlier noted potentially higher cost and lower
operational speed factors, etc. associated therewith.
Moreover, other elements of that machine would not be necessarily
compatible with direct insertion techniques. For example, carrier
strip guidance by utilizing jaws to grip the base of the generally
U-shaped strip could present interference with movement of an
insertion ram if direct insertion were attempted. Moreover, these
jaws could undesirably rigidify the strip to render it unsuited for
both continuous feed and direct insertion without breaking the
strip.
In addition, force cooperation between an insertion ram and the
pins to be inserted involved, in that machine, the use of sliding
blocks that needed to be displaced during continued downward ram
movement to effect insertion. The mass of the blocks and control of
the block movement through cooperation with an anvil gives rise to
the need for controlling several mechanical movements and the
possibility of jamming.
Other prior proposals which do relate to direct insertion of pins
from a carrier strip are disclosed in Bakermans U.S. Pat. No.
3,605,237, issued Sept. 20, 1971, and in DeShong U.S. Pat. No.
3,307,244, issued Mar. 7, 1967. According to proposals such as
these, the carrier may be advanced by incrementally pushing on a
metal strip with which the pins are integral. Guidance of the strip
along a structurally defined path may be provided. At the insertion
location, the pins are gripped by alignment clamps, and a ram and
anvil like combination is employed to sever the pin from the strip
and insert the pin.
It will be recognized that, although such machines might be
desirable for some purposes, the may not be entirely acceptable for
a number of reasons. Some of these relate to the particular type
carrier strip to which these proposals are essentially restricted,
while others are more general in nature.
For example, the need for equipment and sequencing associated with
severance of the pins from the strip may present difficulties.
Similarly, use of the particular type feeding and guidance
techniques for the relatively rigid strip might not be acceptable
in the case of a flexible strip such as that with which the present
invention is most particularly useful. Pin orientation equipment
distinct from the carrier might, as earlier noted, also be
undesirable.
Numerous other difficulties associated with carrier strip feeding
and handling, pin orientation, and pin insertion can be
envisioned.
OBJECTS AND BRIEF SUMMARY OF PREFERRED FORMS OF THE INVENTION
Recognizing the carrier strip feeding and handling, pin
orientation, and pin insertion difficulties associated with removal
of a pin from a carrier strip and insertion of the pin into a
substrate, it is a general object of the present invention to
provide a novel apparatus for inserting pins into such a
substrate.
It is a particular object of the present invention to provide such
a novel apparatus especially suited for use in connection with
direct pin insertion from flexible carrier strips carrying pins
discrete from the strips.
It is a further object of the present invention to provide, in such
apparatus, a novel carrier strip guidance technique.
It is an additional object of the present invention to provide, in
such apparatus, for strip guidance with novel guide blocks that
enhance pin positioning while accomodating strip flexibility.
It is another object of the present invention to provide, in such
apparatus, a novel technique for incrementally advancing the
carrier strip.
It is yet another object of the present invention to provide, in
such apparatus, for incremental carrier strip advancement utilizing
an escapement mechanism.
It is a still further object of the present invention to provide,
in such apparatus, for novel controlled force relationship between
pins and a ram during direct pin insertion from the flexible
strip.
It is still another object of the present invention to provide, in
such apparatus, for novel cooperation between an anvil assembly and
a circuit board to enhance pin alignment with circuit board
receiving holes.
Preferred forms of the present invention intended to accomplish at
least some of the foregoing objects entail apparatus for direct
insertion of terminals from the carrier strip into a substrate.
Preferably, this strip is comprised of a flexible elongate member
of generally U-shaped cross-section defined by a base portion and
contiguous legs. The carrier strip includes a plurality of carrier
openings in the legs for releasably mounting a plurality of
terminals generally orthogonally to the direction of extent of the
strip. The terminals so mounted project outwardly from both legs
and along the space defined between these legs. A series of
indexing openings are provided in the base portion of the carrier
strip.
Apparatus according to the present invention includes in addition
to carrier strip feeding means and carrier strip guiding means, a
ram assembly and an anvil assembly cooperable with the pins mounted
on the carrier strip for removal of those pins from the strip and
insertion of the pins into a circuit board. Also included are
elements for insuring correct positioning of the pin receiving
circuit board relative to the ram assembly and anvil assembly.
Movable ram means of the ram assembly is operable to act on the
pins carried by the strip to remove the pins directly from that
strip and insert the pins into the substrate or circuit board. This
movable ram means includes a pin receiving opening, and means for
resiliently gripping the pin within that opening.
The anvil assembly includes movable locating finger means
cooperable with the substrate for locating the substrate in a
position for reception of the pins acted upon by the ram means.
This movable locating finger means is movable between an extended
and retracted positions. In the extended position, the locating
finger means may be received within a pin receiving aperture of the
substrate. In this connection, an indicating means, such as a light
source, is operable to provide a visual indication of the reception
of the locating finger means in that receiving aperture.
When the locating finger means is displaced from its extended
position, such as by engagement with solid portions of the
substrate as would occur if the substrate were improperly oriented
for pin reception, sensing means is operable to effect disabling of
the ram means.
A manually operable substrate mounting fixture may be employed to
properly position the substrate for pin reception.
Orientation of the anvil assembly and the ram assembly is such as
to establish a pin removal and insertion zone therebetween. Proper
orientation of the carrier strip, for pin removal and insertion on
movement of the ram means into that pin removal and insertion zone,
is provided by carrier strip guiding means.
This guiding means comprises guide block means for establishing the
path of travel for said carrier strip in a direction to intersect
the pin insertion zone. The guide block means include means
defining a ram movement zone in the pin insertion zone, as well as
means defining first and second carrier strip guide channel
sections along the carrier strip path of travel on opposite sides
of that ram movement zone.
The first guide channel is operable to guide a portion of the
carrier strip on which the pins are mounted, and includes a
generally cross-sectionally U-shaped recess defined by recess wall
means having a base and legs. The base and legs are cooperable
externally with the base and legs of the carrier strip and those
portions of the carrier strip legs that extend from the base to the
pins.
Also included in the first guide channel are generally upright wall
faces that extend above and below the recess. These wall or track
faces respectively cooperate with portions of the pins extending
above and below the legs of the carrier strip.
A projecting flange means of the first guide channel is generally
cross-sectionally U-shaped and projects toward the guide channel
recess. A generally upright face of this projecting flange means is
cooperable with the portion of the pins extending between the legs
of the carrier strip. Further faces of the projecting flange means
are cooperable internally with those portions of the legs of the
carrier strip projecting from the pins.
The second guide channel is operable to guide a portion of the
carrier strip with the pins removed. The legs of the carrier strip
with the pins so removed are deflected in the direction of pin
insertion after being acted on by the movable ram means. The second
guide channel includes a generally L-shaped recess having a base
and an upper leg respectively cooperable with the base of the
carrier strip and one of the carrier strip legs adjacent the zone
of deflection, at the juncture of that leg and the carrier strip
base.
A second projecting flange means projects into the generally
L-shaped recess and is cooperable with that leg of the carrier
strip adjacent its free end.
Aspects of the present invention in connection with guidance of the
carrier strip entail establishing a constraining guide path for
that strip, with the constraint being sufficient to accomodate
carrier strip flexibility while preventing significant twisting,
pivoting or translation of the strip, and also rigidifying the
strip on opposite sides of the ram means movement zone. The
orientation between the carrier strip and pins, and the previously
mentioned elements of the first and second guide channels
cooperable therewith, provide, with limited clearance, the desired
constraining relationship.
The carrier strip feeding means includes reel means for supporting
the strip for movement along its path of travel. Also included is
driven sprocket means cooperable with the indexing openings of the
carrier strip to continually bias the strip for movement along that
path. Escapement fingers project through openings in the guide
blocks for alternating engagement with the indexing openings of the
carrier strip on opposite sides of the ram movement zone. The
escapement means is operable to provide for sequential advancement
into the ram movement zone of pins carried by the strip.
Further aspects of the present invention involve resisting
displacement of the pins from the carrier strip, by a force
sufficient to provide generally uniform deflection of those
portions of the carrier strip legs that are in the ram movement
zone during the movement of the ram which effects removal of the
pin from the strip. The resistance force so applied is additionally
operable to cause relative movement between the pin and the moving
ram means, so that the pin is forced to its limit position gripped
within the pin receiving opening of the ram means. At the same
time, the resistance force is at a level where undue abrasion of
the pins during insertion is avoided.
In the preferred form of the invention, this desired resistance is
provided by resiliently biased jaw means having jaw portions
mounted for pivotal movement, below the pin path of travel zone,
toward and away from the ram movement zone. The jaws also include
tapered faces operable to aid in aligning the pin in the direction
of its intended path of travel.
Other objects and advantages of the present invention will become
apparent from the subsequent detailed description thereof, in
connection with the accompanying drawings, in which like numerals
refer to like elements, and in which:
THE DRAWINGS
FIG. 1 is a view according to the present invention showing a pin
terminal insertion machine in perspective along with a partially
broken away perspective illustration of a fixture for holding and
orienting a circuit board for receiving the pins;
FIG. 2 is a side elevational view of the pin insertion machine
shown in FIG. 1, partially broken away to depict the drive employed
in connection with take up of the strip serving as a carrier for
the pins;
FIG. 3 is a partial top plan view of the insertion machine shown in
FIGS. 1 and 2, illustrating in phantom the path of travel of the
carrier tape;
FIG. 4, is a partial front elevational view of the post insertion
machine of FIG. 1, illustrating in phantom the carrier strip
travelling through guide blocks, showing the orientation of the
guide blocks relative to the insertion ram and back-up jaws, and
depicting in cross-section the anvil assembly partially shown in
FIG. 5, with the orientation of the pin receiving circuit board
shown in phantom.
FIG. 5 is a partial side elevational view illustrating the anvil
assembly of the insertion machine of FIG. 1;
FIG. 6 is a top plan view taken generally in the direction of line
6--6 in FIG. 4 and illustrating the escapement mechanism utilized
for advancement of the carrier strip in the insertion machine of
FIG. 1.
FIG. 7 is an exploded perspective view of the guide block assembly
of the insertion machine of FIG. 1;
FIG. 8 is a perspective view of substitute back-up jaws that may be
mounted on the guide block assembly of FIG. 7 in connection with
insertion of long terminal pins;
FIG. 9 is a cross-sectional view taken along line 9--9 of FIG. 4
and showing guidance of the carrier strip at its path of travel
location prior to positioning under the ram assembly;
FIG. 10 is a cross-sectional view taken along line 10--10 of FIG. 4
and illustrating the pin location prior to removal from the carrier
strip;
FIG. 10A is a cross-sectional view similar to that of FIG. 10, but
showing the ram assembly displaced for pin insertion;
FIG. 11 is a cross-sectional bottom plan view taken along line
11--11 of FIG. 10;
FIG. 12 is a cross-sectional front view taken along line 12--12 of
FIG. 4 and showing guidance of the carrier strip at its path of
travel location subsequent to positioning under the ram
assembly;
FIG. 13 is cross-sectional view taken generally in the direction of
lines 13--13 of FIGS. 9 and 12 and depicting displacement of the
back-up jaws during a pin insertion operation, as well as the
orientation of fingers of the escapement mechanism relative to the
carrier strip;
FIG. 14 is a generally schematic plan view illustrating the fingers
of the escapement mechanism prior to and subsequent to carrier
strip advancement;
FIG. 15 is a generally schematic plan view similar to that of FIG.
14 but showing displacement of the escapement mechanism fingers to
effect carrier strip advancement; and
FIGS. 16 and 17 are partial perspective views showing respectively
short and long pins mounted on carrier strips for insertion by the
machine of FIG. 1.
DETAILED DESCRIPTION
General Structure and Operation
With particular reference now to FIGS. 1-3, a preferred form of
post insertion machine 20 according to the present invention may be
seen. The machine 20 includes a support base 22 for mounting the
machine on a suitable floor positioned table (not shown) or the
like.
Overlying and projecting outwardly from the upper face of the base
22 is a worktable like fixture 24 positioned on the base in any
suitable manner. This work table fixture 24 provides a support for
a manually positionable jig 26 on which a post receiving circuit
board 28 may be mounted.
This jig 28, hereinafter more fully described, incorporates a
safety feature to insure proper placement of an operator's hands
out of the insertion area during post insertion.
The post insertion zone may be considered to be the zone extending
between a post insertion ram assembly 30 and an anvil assembly 32
projecting upwardly from the support base 22 through the table-like
fixture 24. During post insertion, a ram arm of the ram assembly
30, hereinafter more fully described, is operable to displace a
post into a position received in a hole in the circuit board 28
located directly above the anvil assembly 32. It will also be
appreciated that in accordance with the present invention,
simultaneous insertion of multiple posts is also envisioned.
Each post so inserted is one of a series of posts or pins 34
mounted on a carrier strip or tape 36. (See FIGS. 16 and 17.) The
strip 36 is advanced along a path of travel transverse to and
intersecting the post insertion zone.
The path of travel is established to extend from a reel 37 about
which the strip 36 is wound to a take-up sprocket 38 cooperable
with a guide pin 39 that is removable for initial positioning of
the tape on the sprocket, (See FIG. 3.) The reel 37 and the take-up
sprocket 38 may be mounted in any suitable manner on the machine
base 22, preferably adjacent the rear portion thereof on opposite
sides of a generally upwardly projecting, and forwardly extending
L-shaped support arm 40.
Suitably mounted on the upper end of this support arm 40, adjacent
its most forwardly extending portion, is a working cylinder 42 of
the ram assembly 30. It will be appreciated that the illustrated
ram assembly 30, including this working cylinder 42, may be
pneumatically or hydraulically operated through a suitable number
of conduit connections such as the one schematically shown at 44 in
FIG. 1.
Depending from the forwardly extending portion of the support arm
40 at a location beneath the ram assembly 30, is a guide block
assembly 46, hereinafter more fully described. Attachment of this
guide block assembly 46 to the support arm 40 may be accomplished
by means of mounting plates 48 on opposite sides thereof. Although
not illustrated, these plates may have cut out portions to permit
visual access to elements disposed therebetween.
Two suitably mounted guide pulleys 50 and 51 project from the guide
block assembly 46 to a location outward of the mounting plates 48.
These guide or idler pulleys are positioned at a vertical level
essentially coplaner with the take-up sprocket 38 and the carrier
reel 37. The path of travel of the carrier strip 36, depicted in
phantom in FIG. 3, is initiated by leading the strip from the reel
37 and about the first guide pulley 50, and then threading the
strip through a guide channel defined by the guide block assembly
46 in a manner to be described below. The strip is then passed
about the other guide pulley 51 to the sprocket 38.
At this juncture it may be noted that the guide channel of the
guide block assembly 46 lies in the vertical plane which includes
the axis of the ram assembly 30 and is parallel to the vertical
plane that includes the axes of the guide pulleys 50. Advancement
of the carrier tape 36 along that guide channel is thus operable to
position pins 34 in the post insertion zone beneath an axially
extensible ram arm of the ram assembly 30.
This advancement of the strip 36 may be effected by driving the
take-up sprocket 38 with a suitable driving arrangement, such as an
electric motor and gearing arrangement shown generally at 52 in
FIG. 2 as being housed with the machine support base 22. Through
this driving arrangement 52, the carrier tape 36 may be placed in
tension between the guide pulleys 50 and 51, and sequentially
advanced for positioning of sequential posts 34 beneath the ram
assembly 30. In a manner described more fully below, particularly
in connection with FIGS. 14 and 15, sequential advancement and
accurate positioning of the tape and pins is controlled by means of
a solenoid operated escapement mechanism 53 (not shown in FIGS.
1-3).
A suitable control circuit (not shown) is employed to effect, among
other things, operation of the escapement mechanism 53 after post
insertion and retraction of the ram member. In this connection, a
control circuit switch 54 may be located at the side of the machine
base 22.
Also positioned in that location is a take motor switch 56 for
controlling the on or off condition of the sprocket drive 52. The
take-up force exerted on the carrier strip 36 is essentially
continuous with the motor switch in its on position. However, the
escapement mechanism 53 prevents strip advancement except at
appropriate times. Timing relationships between operation of the
escapement mechanism 53 and strip movement, caused by take-up force
generated by the drive 52, can be adjusted by means of a rheostat
control 58 suitably electrically connected to the take up
motor.
The Circuit Board Jig and Circuit Board Positioning
With renewed reference to FIG. 1, the preferred technique and
structure for properly orienting the circuit board 28 for pin
reception will be appreciated. It will be recalled that the circuit
board 28 is mounted in the manually positionable jig 26.
This jig 26 may be comprised of an open rectangular frame with
sides formed from interconnected L-shaped pieces of metal 60 and
61. Support legs 62 depend therefrom at suitable locations.
Projecting between two opposite sides 60 of the frame are two
circuit board support beams 64.
These beams 64 are transversely apertured adjacent each of their
ends for reception of bars 66 which define tracks on which the
beams may slide. Once proper spacing of the beams 64 is
established, the beams may be locked in position on the bars 66 by
means of set screws or the like (not shown) extending into holes in
the tops of the beams adjacent the location of the bars 66.
The beams are also provided throughout their length with a series
of further holes 68. Clamps 70 may be securely positioned on the
tops of the beams by means of fasteners 72 cooperable with these
holes. These clamps 70 may be stepped adjacent their edges facing
inwardly of the beams 64 for reception therebeneath of the edges of
the circuit board 28.
As will be appreciated, the dimensions of the circuit board 28 will
govern the selected adjustable spacing between the beams 64 and the
selected adjustable positioning of the clamps 70. After these
locations are established, the board 28 is firmly clamped against
the upper faces of the beams 64.
The board 28 includes a plurality of rows and columns (not shown in
FIG. 1) of apertures for press fit or other suitable reception of a
portion of the posts 34. In order to aid in proper positioning of
the board apertures for such post reception, a light source 74 is
provided. This light source is mounted in any suitable manner to
direct a beam of light in the general vicinity of the anvil
assembly 32.
The anvil assembly 32 includes a projecting locating finger 76 (See
FIG. 2) at its upper end. This projecting finger or pin 76 is sized
to fit into the post receiving apertures and has a diameter
approximately equal thereto.
A visual indication that the manually positionable jig 26 has been
properly positioned with the anvil finger 76 so received in the
board aperture is provided by reflection from that finger of the
beam of light established by the light source 74. When the board
has not been properly positioned, the beam of light strikes solid
portions of the board, producing a distinctly different visual
effect.
After orientation of the board with the anvil finger 76 properly
positioned in the aperture, the ram may be activated. In order to
ensure against location of an operator's hands in the pin insertion
zone, activation of the ram may be controlled by two manually
operable switches 77 located on opposite side legs 61 of the jig
frame. As will be appreciated, suitable electrical connection can
be made between these switches 77 and appropriate controls for ram
activation so that ram activation is not possible unless both
switches 77 are simultaneously depressed.
The Anvil Assembly
It will be recognized that in the absence of proper circuit board
positioning, damage to the pins 34 as well as to the insertion
machinery may result by jamming caused through engagement of the
pins against solid portions of the board 28. In accordance with the
present invention, ram activation is prevented unless the anvil
finger 76 is properly received in a pin receiving aperture. With
reference to FIG. 5 and the bottom portion of FIG. 4, the structure
of the anvil assembly 32 for so preventing ram activation may be
seen.
The anvil finger 76 is slidably received in a necked housing 78
assembly of the anvil assembly 32. Below the necked portion of this
housing 78 an enlarged retainer member 80, to which the anvil
finger 76 is attached, is also slidably received.
This retainer member 80 is biased by a coil spring 82 located in
the housing 78 between the bottom of the retainer member 80 and a
lower internal housing shoulder 84. Normally, the action of the
spring 82 urges the retainer member 80 against an upper internal
housing shoulder 86, to maintain the anvil finger 76 projecting
from the housing 78 by an amount substantially equal to the depth
of an aperture in the board 28.
Projecting downwardly from the retainer member 80 through the lower
end of the housing 78 is a stem 88 about which the coil spring 82
is positioned. This stem 88 may be suitably connected, adjacent its
lower end protruding from the housing, to a cam member 90 or the
like.
A contact member 92 of a suitable sensing means such as a
microswitch 94 may be resiliently biased downwardly against the cam
member 90. The biasing force of the contact member 92, is, of
course, less than that which is sufficient to overcome the lifting
bias on the retainer member 80 provided by the coil spring 82.
However, downward movement of the retainer member 80, and the stem
88 connected thereto, displaces the cam 90 downwardly, and permits
the biased contact member 92 to disengage from another microswitch
contact 96 with which it is normally held in engagement.
Suitable electrical connections between the microswitch 94 and the
control circuit for ram activation may be established to allow ram
activitation only when the microswitch contacts 96 and 92 of the
microswitch are engaged. In this fashion, undesirable ram
activation without reception of the anvil locating finger 76 in a
circuit board receiving hole will be prevented, inasmuch as with
solid portions of the circuit board resting on that finger 76, the
stem 88 and cam 90 will be downwardly displaced against the bias of
the coil spring 82 to break contact at the switch 94.
During actual insertion of a pin 34 into a receiving hole of the
circuit board 28, the portion of the pin projecting beneath the
board bottom is received in the anvil housing 78 in the zone from
which the locating finger 76 is downwardly displaced. In instances
where jamming of a pin 34 in the anvil assembly might thereafter
occur, the control circuitry is such that the resultant downward
displacement of the stem 88 and cam 90 will also be operative to
prevent subsequent cycles of ram activation during attempts at
unjamming.
In this connection, it may be noted that the retainer member 80 is
provided with projecting arms 98 extending through slots 100 in the
anvil housing 76 to permit manual displacement of the retainer
member 80 and connected elements.
The Carrier Strip and Pins
With reference now to FIGS. 16 and 17, the carrier strip 36 and
pins 34 for insertion in accordance with the present invention may
be seen.
The elongate flexible, polyester strip 36 is generally U-shaped in
transverse cross-section, and is comprised of a base portion 101
and two projecting legs 102 integral therewith. The base portion
includes a series of indexing holes 103 for feeding of the strip as
described below.
Each leg portion 102 is provided with a plurality of longitudinally
spaced necked carrier slots 104, which support a series of pins 34
generally orthogonally to the direction of strip extent. Adjacent
carrier slots 104 are separated by relief slots 105. These relief
slots add flexibility to the strip.
Sequential relief slots 105 define tab portions 106 of the strip
legs 102. The pins 34 are thus supported by these tabs 106 which
contain the carrier slots 104.
The relatively short pins 34 illustrated in FIG. 16 are elongate
members having a tail portion 107, a widened body portion 108 and a
contact portion 109. The widened body portion may be press fit into
the receiving apertures of the circuit board 28, with the tail
portion 107 projecting therebelow.
Relatively long pins illustrated in FIG. 17 also include a tail
portion 107, a widened body portion 108 and a contact portion 109.
However, unlike the pins of FIG. 16, the tail portion 107 of the
pins of FIG. 17 is longer than the contact portion 109.
For a purpose hereinafter more fully described the tail portions
107 of the pins of FIG. 17 are embraced by the carrier slots 104,
whereas the contact portions 109 of the pins of FIG. 16 are so
embraced.
In typical examples of the relative dimensions of the short and
long pins 34 of FIGS. 16 and 17, the contact portion 109 of both
pins would be about three eighths of an inch in length, while the
length of tail portions 107 would be about one-sixteenth inch and
five-eighths inch respectively.
The pins 34 may be snapped into the carrier slots 104 in any
suitable manner. In this connection, reference may be had to
copending United States patent application Ser. No. 288,851, filed
Sept. 13, 1972 for further details regarding the pins 34 and
carrier tape or strip 36 on which they are mounted, as well as for
a general description of a technique for carrier strip advancement
and displacement of the pins from the strip by a ram into press-fit
reception into the circuit board. The disclosure of that
application, assigned to the assignee of the present invention, is
hereby incorporated by reference.
Guide Block Assembly and Carrier Tape Guidance
In FIG. 4, threading of the carrier strip or tape 36 through the
guide channel defined by the guide block assembly 46 is illustrated
in phantom. The manner in which this guide channel is defined and
the structural members of the guide block assembly 46 are best seen
in FIG. 7.
As shown therein, the guide block assembly includes a front block
110 and a rear block 111. These front and rear blocks include
mating planar faces 112, 113 with assembly apertures 114 and 115
extending therethrough. These apertures are located so that when
the mating planar faces 112, 113 are in abutment, the apertures 114
of the front block 110 are aligned with those 115 of the rear block
111.
The blocks may be then assembled together by machine bolts 116 (see
FIGS. 9 and 12) cooperating with threads in the apertures 115 of
the rear block 111. The assembly apertures 114 of the front block
110 may communicate with enlarged recesses 118 for reception of the
heads of the machine bolts 116.
With the blocks 110 and 111 so assembled, a tape guiding channel
having first and second sections generally indicated at 119 and 120
in FIGS. 9 and 12, is defined. As subsequently described, the
configuration of the channel section 119 in the tape path of travel
zone prior to passage of the tape beneath the ram assembly 30 (see
FIG. 9) differs from the configuration of the channel section 120
in the tape path of travel zone after the tape passes the location
of the ram assembly (See FIG. 12).
This difference in configuration of the channel sections 119 and
120 is attributable to the difference in tape configuration before
and after the tape passes a ram movement zone, indicated at 122 in
FIG. 13, defined generally centrally of the guide block assembly
46. In this ram movement zone 122 a ram member is operable to
remove the pins 34 from the tape 36 to effect pin insertion into
the board 28 as described more fully below.
In so doing, the ram member deflects the tape tabs 106 downwardly
into the configuration shown in FIG. 12. The second guide channel
section 120 is arranged to cooperate with the tape 36 in that
deflected condition, while the first guide channel section 119 is
arranged to cooperate with the tape 36 in the condition shown in
FIGS. 16 and 17.
Turning now specifically to FIGS. 7, 9 and 12, the configuration of
the first and second channel sections 119 and 120 may be more fully
appreciated. Each of these sections 119 and 120 is defined by
structure of both the front and rear blocks 110 and 111.
In connection with defining the first channel section 119, the
front block 110 is provided with an insert 122.
This insert 122 is received in a generally L-shaped cut out section
machined in the block 110. A groove 124 is additionally machined in
the block face defined by the cutout.
The insert 122 includes a main body portion having a
cross-sectional configuration substantially identical to the
cross-sectional configuration of the L-shaped cutout section. In
addition, the insert 122 includes a locating flange 126 for mating
reception of the insert in the L-shaped cut out section. Securing
of the insert 122 in this position may be accomplished by means of
machine screws 128 cooperable with suitable apertures in the
inserts and the block 110.
Projecting outwardly from the insert 122 is a guiding flange 130
with a tapered lead in portion 131. As may be seen in FIG. 9, this
guiding flange 130 has a height dimension substantially equal to
the distance between the upper and lower legs 102 of the generally
U-shaped tape 36. The width of the guiding flange 130 is sufficient
so that the front face of that member projects to a location
substantially adjacent the pins 34 when the tape 36 is threaded
through the channel, as shown in FIG. 9.
When the tape is so threaded, the base 101 of the generally
U-shaped tape 36 is positioned substantially adjacent the base of a
similarly shaped recess 132 machined in the rear block 111. This
recess 132 has a longitudinal extent substantially equal to the
guiding flange 130 of the front block insert 122. The height of the
recess 132 is substantially the same as the distance between the
legs 102 of the tape.
As will be appreciated from the foregoing description of the first
channel section 119, the walls of the recess 132 provide guide
surfaces cooperate with the base 101 of the tape 36 and with the
external portions of the tape legs 102 in their extent from that
base 101 to the pins 34. Similarly, the walls of the guide flange
130 cooperate with internal portions of those tape legs 102 in
their extent projecting beyond the pins 34, and with the extent of
the pins 34 between the tape legs 102.
An additional portion of the front face 113 of the rear block 111
is also machined away along the length of the recess 132. In this
fashion, guide rails 134 are established immediately above and
below the recess 132. The width of this machined away portion of
the rear block 111 is such that when the front and rear blocks 110
and 111 are assembled, the front faces of these guide rails 134 lie
substantially adjacent the portions of the pins 36 projecting above
and below the tape legs 102.
Thus, the first channel section 119 includes walls, provided by the
rails 134, for guiding cooperation with these projecting pin
portions. The guidance surfaces included in that channel section
119 are spaced and dimensioned relative to one another to provide
for clearance between those surfaces and the tape 36 as well as the
pins 34 at all locations. This clearance is, however, sufficiently
small so that it is not shown in FIG. 9.
It will, nevertheless, be appreciated that the first channel
section 119 is so defined as to limit significant excursion of the
tape and pins 34 in both the vertical and horizontal planes.
Similarly, twisting of the tape 36 and supported pins 34 is
minimized. Although the tape 36 and pins 34 are constrained by the
channel section 119, the clearance is sufficient to accomodate tape
flexibility and to avoid binding during tape advancement.
Of particular significance in relation to the first channel section
119 is the essentially three location support provided for the pins
34, namely along the portions projecting above and below the tape
legs 102 and along the portion therebetween. As will be noted
below, by reason of the provisions made for tape advancement
through the earlier mentioned escapement mechanism 53 (FIGS. 14 and
15) tension in the tape at the zone of the first channel section
119 is somewhat limited. Therefore, tape twisting possibility is
significant.
Such twisting could result in camming of the pins 34 against the
guiderails 134 and subsequent forcing of the pins free from the
carrier slots 104. This possibility is resisted by the guiding
flange 130.
At the same time, the guide rails 134 add stability and lend
rigidity to the somewhat slack tape. In this fashion, adequate tape
support on the entry side of the post insertion zone (where the
first channel section 119 ends) is established at a level
compatible with forces generated during direct pin insertion.
At the exit side of the pin insertion zone, the second channel
section 120 commences. At this channel section 120 the front block
110 is provided with another insert 136. The machining of the block
for reception of this insert 136, and the actual assembly of the
insert 136 are similar to that in connection with the block insert
122 associated with the first channel section 119.
The block insert 136 of the second channel 120 also includes an
elongate guide flange 138. This guide flange 138 has a greater
width than and a smaller thickness than the other guide flange
130.
As previously mentioned, the tabs 106 of the tape legs 102 are
deflected during pin insertion. At that time, these tabs take on a
set or degree of stable deformation. The orientation of the guide
flange 138 in the second guide channel 120 is such that the upper
wall thereof cooperates with the free end of the upper deflected
tabs 106 to stabilize the tape portion from which the pins 34 have
been removed.
In the portion opposite the second guide flange 138, the rear block
11 is cut away in alignment with the generally U-shaped recess 132
of the first guide channel 119. However, there is no provision for
pin guidance rails such as those associated with the first guide
channel, so that the resulting cut away or recess portion 140 takes
on a generally inverted L-shaped configuration.
The back wall of this recess 140 provides guidance cooperation with
the base 101 of the tape, while the upper recess wall provides
guidance cooperation with the upper deflected tab 106 adjacent its
juncture with the base 101 at which deflection occurs. At the same
time, the lower deflected tab 106 is free from guidance surfaces.
In this fashion, reaction forces that might be otherwise be
produced by engagement of portions of the block with bottom tab 106
so as to induce twisting of the tape are avoided.
As best viewed in FIG. 7, it will be seen that the second guide
flange 138 includes a lead in portion with a compound profile
including a tapered portion 142 adjacent the pin insertion zone.
This tapered portion 142 is operable to gradually cam the deflected
upper tabs 106 of the tape upwardly in the second channel section
120. Thus, the possibilities of the introduction of twisting forces
and tape feed interference by reason of snagging of non-uniformly
deflected tabs 106 on the guide flange 138 are minimized, and tape
uniformity is enhanced.
As in the case of the first channel section 119, the second channel
section 120 is dimensioned to provide clearance for the tape. In
addition, the second channel section 120, like the first section
119, is arranged to stabilize the tape against twisting and
significant vertical and lateral excursions. In this connection,
inasmuch as tape tension is greater in this section, the second
guide channel section 120 does not require as small of a clearance
between the front face of the guide flange and the adjacent moving
portion, in this case the inside, of the tape base 101.
The provision in accordance with the present invention on opposite
side of the pin insertion zone for tape guidance that constrains
the tape, but does not induce significant drag to resist feeding,
is particularly significant from the standpoint of proper
positioning of the pins in the insertion zone. Uncontrolled tape
deflection on either side of that zone, i.e., in the portion of the
tape supporting the pins 34 or in the portion of the tape from
which those pins have been removed, could result in improper
alignment between the pins and the ram. The tape guide guidance
channels 119 and 120 lend sufficient rigidity to the flexible tape
to enable use of the tape as the sole means of support for the pins
during actual insertion. Direct insertion of the pins from their
support position on the tape 36 avoids the need for separate
equipment to remove the pins 34 and stabilize them during
insertion.
Returning again to FIG. 7, it will be seen that the rear block 111
is provided with two apertures 142 and 144 on opposite sides of the
post insertion zone. It will also be noted that the guide flange
138 projecting from the second block insert 136 is provided with a
recess 146 alignable with one of these apertures 144. The function
of these apertures 142 and 144 and the recess 142 will be
hereinafter more fully described in conjunction with the function
of the earlier mentioned escapement mechanism 53.
With continued reference to FIG. 7, it may be observed that the
longitudinally extending holes 148 are provided on one end of the
rear block 111. These and similar holes on the other end cooperate
with machine bolts (not shown) to attach the guide block assembly
46 to the mounting plates 48 for suspending that assembly from the
support arm 40. (See, e.g., FIG. 1).
For a purpose described more fully below in connection with the ram
assembly, the front block 110 includes a threaded hole 150 in its
top surface. A set screw 151 (see FIG. 4) in that hole 150 limits
ram travel.
To accomodate ram travel, the rear block 111 includes a generally
T-shaped vertical groove 152 approximately centrally thereof. The
front block is also grooved centrally adjacent its rear face 112 as
indicated at 154 for this purpose. In addition, the front block is
machined away adjacent its front face at the upper and lower
portions thereof, leaving a web 156 (see FIGS. 10 and 10A)
interconnecting the block portions on opposite sides of the post
insertion zone.
This latter machining of the front block exposes, for viewing, the
tape supported pins located in the pin insertion zone. (See, e.g.,
FIG. 4).
Additionally included in the block assembly 46 beneath the tape
path of travel are two pivotally mounted jaws 158 and 160 mounted
on the rear block 111. The function of these jaws 158, 160, and the
substitute jaws shown in FIG. 8, is hereinafter more fully
explained in conjunction with the description of ram insertion of
the pins 34 into the board 28.
For now, it may only be noted that these jaws, generally mirror
image in appearance, each are fixed to a pivot axle 162 which
projects through holes in a lower zone of the rear block 111. Each
of these axles 162 are suitably fixed to a bifuricated clamp member
164 by means of a set screw or the like. These clamps 164 include
pins projections 166 adjacent their lower ends.
As best shown in phantom in FIG. 4, the clamps 164 are oriented at
oppositely projecting forty-five degree angles relative to the axis
of the ram assembly 30. A coil spring 168 biases the clamps to that
position, in which position pivot arms 170 of the jaws abut the
upper surface of an inverted generally L-shaped recess 172 further
cut away beyond the guide channel recesses 132 and 140.
During post insertion, the jaws 158 and 160 are pivoted about the
axis defined by the axles 162 against the bias provided by the
spring 168.
The Ram Assembly and Pin Removal and Insertion
In FIGS. 10 and 10A and 11, details of the ram assembly 30 may be
seen. The illustrated ram assembly includes, in addition to the
previously identified working cylinder 42 (FIG. 1), a reciprocable
ram arm indicated at 174.
This ram arm is partially received in a tubular housing 175 that is
suitably mounted in alignment with the working cylinder 42. At the
upper end of the ram arm housing 175, the ram arm is operatively
connected to a piston (not shown) received within and controlled by
pressures within the working cylinder 42.
The lower end of the ram arm 174 is comprised of a body section 176
and a nose section 178. This nose section 178 is defined by a
reduced portion 180 of the body section and a gripping insert 182
primarily received within the body section.
As best seen in FIG. 10A, the flat insert 182 includes a main
portion 184 and a nose projection 186. The main body portion 184 is
the portion received in the body section 176 of the ram arm, and
the nose projection 186 completes the nose section 178 of the ram
arm by complementing the previously mentioned reduced portion
180.
Positioning of the insert 182 is accomplished by means of a tab 188
on its nose projection 186. This tab 188 is receivable in an
opening 190 in the reduced body portion 180. In addition, the main
portion 184 of the insert 182 includes a recess 192 cooperable with
a set screw 194 (see FIGS. 4 and 13) and an opening in the body
section 176 of the ram arm to firmly maintain the insert 182 in
position.
As will be appreciated from the view of FIG. 11, the ram arm 174
has a cross-sectional configuration complementary to the ram arm
receiving grooves 152 and 154 in the guide blocks 110 and 113. The
ram arm is thus able to traverse the guide block assembly along a
ram movement zone intersected by the tape path of travel zone, to
remove the pins 34 and effect insertion thereof into the circuit
board 28.
Upon movement of the ram arm 174 into engagement with the upper end
of the pin 34 supported in the ram movement zone, the upper end of
that pin is received by the nose section 178 of the ram arm as
shown in FIG. 10A. In this connection, it should be noted that the
nose projection 186 of the insert functions as a flexible gripping
spring which accomodates reception of the pin 34 and grips that pin
against the reduced body portion 180. The clearance between these
two members defines a pin receiving opening of the ram arm 174.
After a given amount of downward movement of the ram arm 174, the
ram arm overtakes the pin 34 until the pin is firmly seated in that
receiving opening. The limit of travel of the pin into the
receiving opening is established by engagement of the upper end of
the pin with the positioning tab 188 of the insert 182.
With renewed references to FIG. 7, the function of the jaws 158 and
160 during the pin removal and insertion operation may be more
fully appreciated.
Upon initial engagement of the ram arm 174 with the upper end of a
pin 34, the support tabs 106 will begin to deflect downwardly.
Inasmuch as variations in tape tension and other tape conditions
may result in non-uniformity of this deflection, and thereby
produce enforced misalignment of the pin when the pin is acted on
by the ram arm, it is important to insure pin alignment despite
such conditions.
One function of the jaws 158 and 160 is to accomplish this. The
jaws, being positioned close to the bottom end of the pin supported
by the tape, resiliently engage that pin end upon a small
deflection of the tabs 106.
This resilient resistance aids in accomplishing relatively uniform
deflection of the tabs 106 in repeated insertion operations,
thereby aiding maintenance of the pin in longitudinal alignment
with the pin path of travel. The resilient resistance by the jaws
to pin displacement also enforces relative movement between the pin
and the ram arm 174 at a relatively controlled rate. In this
manner, the pin becomes smoothly and properly seated in the pin
receiving opening of the ram without being subjected to detrimental
bending and twisting forces.
As will be apparent, such forces would otherwise cause the pin to
be jammed against the circuit board 28 or jammed into the anvil
assembly upon further downward movement of the ram arm 174.
While the magnitude of the resilient back-up force produced by the
jaws is sufficient for the purposes discussed above, the force
level is chosen so that undue abrasion of the pins as they rub
against the jaws is avoided. It will be recognized that such
rubbing is produced as the pins enter the generally V-shaped zone
194 (FIGS. 4 and 13) defined by mutually inclined faces of the
jaws.
The zone 194 so defined provides an additional centering and
aligning means for orienting the pin along its proper insertion
path of travel.
In normal ram operation, with a circuit board 28 located properly
for pin insertion, the ram arm stroke bottoms out against the
circuit board. This bottoming out, coupled with the proper pin
seating dimensions in the ram arm pin receiving opening, produces a
correct displacement of the pin. In other words, the pin is
received in the board receiving holes with proper extensions above
and below the board.
However, ram actuation is sometimes undertaken, for inspection or
other purposes, without a circuit board in place. In such cases,
provision is made to prevent the ram arm 174 from bottoming out
against the anvil assembly 32 and causing damage thereto. For this
purpose, the earlier noted adjustable set screw 151 (FIG. 4) acts
as a stop cooperable with a shoulder 195 (FIG. 4) of the ram arm to
limit its stroke.
Much of the foregoing description has been particularly applicable
to insertion of the relatively short pins from the tape depicted in
FIG. 16. Operations for insertion of the long pins of FIG. 17 are
essentially similar.
However, in the case of the long pins, a substitute (not shown) for
the resilient ram insert 182 is provided. The substitute insert has
an overall configuration similar to the one illustrated in FIG.
10A. Unlike that insert, the equivalent nose projection 186 is
longer, and the body section is received higher up within the ram
body. The terminus of that nose projection still is located
adjacent the illustrated ram arm terminus when the substitute
insert is assembled.
A positioning tab on that nose projection is also located at a
level to cooperate with a second tab receiving aperture 196 (FIG.
10A).
The longer nose projection and tab location are such as to
accomodate reception of the long tail section 107 of the long pin.
It will be recalled that although the contact portion 109 of the
short pin is acted upon by the ram, the tail portion 107 of the
long pin is acted upon by the ram.
In both instances it is the longer of the tail and contact portions
of the pin that are acted upon and substantially fully received by
the ram. The reason for this is to limit the free extension of the
pin to the smallest length dimension so as to minimize alignment
and bending problems.
It will, however, be appreciated that in the case of long pin
insertion, the circuit board is positioned in an upside down
posture for pin reception. This positioning is dictated by the fact
that the contact portion 109 of the assembled pins are to project
from the top of the circuit board, and the tail portions 107 of the
pins are to project from the bottom for wire wrapping or the
like.
When the longer pins of FIG. 17 are to be inserted, the jaw
assembly illustrated in FIG. 8 is substituted for the jaw assembly
of FIG. 7. This substitute jaw assembly includes the axles 162 and
arms 170, as well as the jaws 158 and 160. However, these jaws 158
and 160 are supported by arms 198 at a sufficient level beneath the
pin path of travel to accomodate for the longer length of the pins
34.
Operation of the jaw assembly of FIG. 8 is essentially the same as
that of FIG. 7. It has been found that the long pin back-up jaws
can be directly substituted for the short pin jaws without change
of biasing springs 168 (FIG. 4), and with equivalent biasing force
levels consistent with the earlier described functions of the
back-up jaws.
The dimensional relationships and orientations producing this
result, enabling minimizing of parts and simplifying change over of
operation, involve the orientation of the jaw support arms 198 and
the axle clamps 164. In the case of long pin insertion, the axle
clamps 164, in their rest positions are arranged to lie generally
vertical rather than at the angle illustrated in FIG. 4. However,
the jaw support arms 198 are mutually inclined toward one another
at about an angle of forty-five degrees to the vertical.
Carrier Strip Indexing and The Escapement Mechanism
In FIG. 6, the basic structure associated with the previously
identified escapement mechanism 53 may be seen.
This escapement mechanism includes escapement fingers 200 and 202
receivable in the rear guide block holes 142 and 144 intersecting
the tape path of travel. Each of these fingers has a tip cooperable
with the carrier tape indexing holes 103 in the tape base 101.
One finger 200 is directly controlled by a solenoid 204. The other
finger 202 is directly controlled by a spring 206. Longitudinal
movement and positioning of both fingers are related by means of a
suitably mounted pivot arm 208, pivotable about a generally
vertical axis indicated at 210.
The ends of the arm 208 are bifurcated to establish slots 212
cooperable with pin projections 214 located on extensions of the
escapement fingers 200 - 202. It will thus be apparent that
retraction of the solenoid controlled pin 200 effects opposite
movement of the other pin 202 through the pivot arm 208. Similarly,
retraction of the spring controlled pin 202 effects extension of
the other pin 200.
Normally, the spring 206 biases the associated pin 202 to a
retracted position as shown in FIGS. 6 and 14. This places the
other pin 200 in its extended position where its tip is received
within a tape indexing hole 103.
In this extended position that pin 200 prevents the tape from
feeding despite the continuous feeding force generated by the
driven sprocket 37. At the same time, engagement of that pin with
the tape necessarily isolates the tape section leading up to that
pin from some of the feed tension. As earlier noted, special tape
guidance is established in the first guide channel section 119 to
minimize problems associated with this tension isolation.
It is important to note that the relative location of the solenoid
controlled finger 200 does not isolate feed tension transmission to
the tape portion supporting the pin at the pin insertion zone. It
will be recalled that the tape guide channel sections terminate
adjacent the pin insertion zone. Therefore, the solenoid controlled
finger 200 is located close to that zone to give added stability,
imparted by transmitted tension, to the tape in that zone.
After the ram is activated to effect direct insertion of a pin, and
the ram arm 174 is retracted, the solenoid 204 is activated to
retract its associated finger. Suitable circuitry (not shown) is
provided to accomplish this automatically.
In FIG. 6 a microswitch indicated at 216, is shown. This switch 216
is operable to time ram movement in relation to tape indexing
caused by operation of the solenoid 204. In this fashion, ram
activation in the absence of proper indexing may be prevented.
When the solenoid retracts the one finger 200, the other finger 202
is extended against the bias of its associated spring 206.
De-energizing of the solenoid enables that spring 206 to retract
its finger 202 and permits extension of the other pin 200.
From the foregoing, and with reference to the schematic
illustrations in FIGS. 14 and 15 it will be apparent that alternate
extension and retraction of the escapement fingers 200, 202
produces sequential indexing of the tape to sequentially position
each tape carried pin 34 in the insertion zone.
The timing of an indexing operation to ensure proper unit indexing
may be adjusted by operation of the earlier mentioned rheostat
control 58 for the tape drive 52. This raises or lowers the speed
at which the tape advances at that point in time when both fingers
are disengaged from the indexing holes 103. Thus, after the
solenoid controlled finger 200 is retracted, the tape is released
for a time for feeding at a proper rate so that the other finger
202 engages the next in line indexing hole 103 to temporarily
terminate tape advancement.
From FIGS. 14 and 15 it will be seen that the tips of the
escapement fingers 200 and 202 are defined by a straight shoulder
212 and a tapered shoulder 214. The dimensions of these tips and
their relative spacing, as well as the relative size and spacing of
the indexing holes 103, are such that after tape advancement is
temporarily terminated, subsequent solenoid de-energization results
in the finger 200 re-engaging the tape 36 in a time less than that
in which the tape feed speed would cause the next indexing hole to
by-pass that finger.
The next pin is thus placed in position for insertion.
GENERAL SUMMARY OF ADVANTAGES
From the foregoing, it will be apparent that in accordance with the
present invention, a novel and advantageous method and apparatus
for inserting terminal pins in a substrate has been provided.
Of particular significance is the provision for carrier strip
guidance on opposite sides of a pin insertion zone so as to
accomodate strip flexibility while conditioning the strip for
direct insertion. In this connection, the guide channel sections of
the guide blocks may be specifically defined to accomodate the
strip sections with and without the pins.
Also of importance is the provision for resilient back-up forces
with back-up jaws to aid in proper pin orientation during
insertion.
Additionally, the escapement mechanism advancement control to
insure proper positioning for insertion provides further
advantages.
Cooperation between the anvil assembly and the circuit board
enhances pin alignment with the pin receiving holes of the circuit
board. In this connection, disabling of the ram assembly, except
during proper board positioning minimizes the possibility of
damage.
Although the present invention has been described in connection
with preferred forms thereof, it will be appreciated that
additions, modifications, substitutions and deletions may be made
without departing from the spirit and scope of the invention as
defined in the appended claims.
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