U.S. patent number 3,775,219 [Application Number 05/131,191] was granted by the patent office on 1973-11-27 for composite-tape placement head.
This patent grant is currently assigned to Goldsworthy Engineering Inc.. Invention is credited to Ethridge E. Hardesty, Harald E. Karlson.
United States Patent |
3,775,219 |
Karlson , et al. |
November 27, 1973 |
COMPOSITE-TAPE PLACEMENT HEAD
Abstract
An integrally complete composite-tape placement head for direct
attachment to a host gantry type of machine, which tape placement
head is designed to precisely apply preimpregnated fiber reinforced
tape to a work piece. The tape is initially supplied in the form of
a roll with a suitable backing. The tape is automatically peeled
from the backing by a separator mechanism and thereafter applied to
the work piece. A powered cut-off device is actuated by a
photoelectric mechanism to sever the tape at a proper location and
at a preestablished angle. The determination of the pre-established
angle is accomplished by a photoelectric edge sensing
mechanism.
Inventors: |
Karlson; Harald E. (Santa
Monica, CA), Hardesty; Ethridge E. (Pine Valley, CA) |
Assignee: |
Goldsworthy Engineering Inc.
(Torrance, CA)
|
Family
ID: |
22448315 |
Appl.
No.: |
05/131,191 |
Filed: |
April 5, 1971 |
Current U.S.
Class: |
156/363; 156/353;
156/526 |
Current CPC
Class: |
B29C
70/388 (20130101); B29C 70/545 (20130101); Y10T
156/1361 (20150115) |
Current International
Class: |
B29C
70/04 (20060101); B29C 70/38 (20060101); B32b
031/00 () |
Field of
Search: |
;156/353,355,523,526,527,363,522 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Torchin; Norman G.
Assistant Examiner: Kimlin; Edward C.
Claims
Having thus described our invention, what we desire to claim and
secure by Letters Patent is:
1. A tape applicator for applying a tape formed of a plurality of
longitudinally extending filament containing strands to a receiving
surface, said applicator comprising support means, tape supply
means operatively retained by said support means, tape placement
means on said support means for applying said tape to said
receiving surface during relative movement between said applicator
and said receiving surface, means carried by said tape applicator
for applying radiant energy directly to said receiving surface,
means selectively locatable on said receiving surface to generate a
differential reflected radiant energy response at a predetermined
end position on said receiving surface, sensing means including a
radiation active sensing element carried by said tape applicator
and being located to scan the radiant energy reflected from said
receiving surface, said sensing means being operable to generate an
electrical signal responsive to receipt of the differential
reflected radiant energy response upon sensing of said
predetermined end position, and cutting means operable upon receipt
of said electrical signal for automatically severing said tape in
advance of said predetermined end position to form a terminal edge
which will coincide with the predetermined end position, said
cutting means also including means to form said terminal edge with
a proper angle established by and conformable to said predetermined
end position, to thereby form a final structural member comprised
of the tape when the tape is removed from said receiving
surface.
2. The tape applicator of claim 1 further characterized in that
means are provided for rotating said support means so that said
tape is applied to said receiving surface in a direction opposite
the direction of relative movement during application of a previous
tape to said receiving surface.
3. The tape applicator of claim 1 further characterized in that
drive means are provided for causing relative movement between said
tape applicator and said receiving surface, deceleration means
operatively associated with said drive means for decreasing the
speed of said relative movement upon detection of said
predetermined position and in advance of said predetermined
position.
4. The tape applicator of claim 1 further characterized in that
said tape supply means comprises a supply spool of said tape, and
means are operatively associated with said tape supply means for
positively driving said tape supply means to dispense tape from
said supply spool.
5. A tape applicator for applying a tape formed of a plurality of
longitudinally extending filament containing strands to a work
surface, and which strands are preimpregnated with a curable
resin-type matrix, said tape dispensing applicator comprising
support means, tape supply means operatively retained by said
support means for dispensing said filament containing tape,
application means located in proximity to said work surface for
receiving said dispensed tape and applying same directly to said
work surface, radiation type pre-heating means located intermediate
said tape supply means and said application means for passing
radiation into said pre-impregnated tape after dispensing of said
tape from said supply means and during movement of said tape past
said pre-heating means, and motive means for automatically shifting
said pre-heating means to a position where substantial radiation is
not directed toward said tape when said tape is not moving with
respect to said pre-heating means, to thereby form a final
structural member comprised of the strands of tape when the
pre-impregnated tape is cured and removed from the work
surface.
6. The tape applicator of claim 5 further characterized in that the
tape dispensable from the tape supply means is initially provided
with and lies in contact with a removable backing member, means for
removing said backing member from said tape prior to introduction
into a location where it receives said radiation, and further means
for reintroducing said tape into contact with said backing member
after subjection to said radiation.
7. In an applicator for applying reinforcing strands comprised of a
plurality of substantially parallel textile filaments to a work
piece while relative movement exists between said applicator and
work piece; means carried by said tape applicator for applying
radiant energy directly to said work piece, means selectively
locatable on said work piece to generate a differential reflected
radiant energy response at a predetermined end position on said
work piece, sensing means for detecting a predetermined end
position on said work piece representing a desired terminal end
location for the piece of strand being applied to said work piece,
said sensing means including a radiation active element carried by
said tape applicator and being located to scan the radiant energy
reflected from said receiving surface, said sensing means being
operable to generate an electrical signal responsive to receipt of
the differential reflected radiant energy response upon sensing of
said predetermined end position, means operatively associated with
said sensing means for establishing a predetermined angle with
respect to the predetermined end position on said work piece, and
cutting means operatively connected to said sensing means for
automatically cutting said strands to terminate at said desired
predetermined end position and conformable to said predetermined
angle, to thereby form a final structural member comprised of the
strands when removed from said work piece.
8. In the applicator of claim 7, said sensing means comprising a
first radiation active sensing element initially detecting said
predetermined end position, and a second radiation active sensing
element capable of being shifted into a position where said first
and second elements are aligned with said predetermined end
position to thereby establish said predetermined angle.
9. In the applicator of claim 7, further characterized in that said
sensing means comprises a first radiation active sensing element
initially detecting said predetermined end position, and a second
radiation active sensing element capable of being shifted into a
position where said first and second elements are aligned with said
predetermined end position, and stepping motor means for
intermittently shifting said second sensing element until said
alignment is achieved to thereby establish said predetermined
angle.
10. In the applicator of claim 8, further characterized in that
said sensing means comprises a third radiation active sensing
element, and deceleration means operatively connected to said third
sensing element for slowing down a relative movement between said
work piece and applicator upon detecting of said predetermined end
position on said work piece.
11. In the applicator of claim 8, further characterized in that
said sensing means comprises a first radiation active sensing
element initially detecting said predetermined end position, a
second radiation active sensing element capable of being shifted
into a position where said first and second radiation active
sensing elements are aligned with said predetermined end position,
stepping motor means for intermittently shifting said second
sensing element until said alignment is achieved to thereby
establish said predetermined angle, and means operatively connected
to said stepping motor means for shifting said cutting means to
conform to said predetermined angle.
12. A tape applicator for applying a tape formed of longitudinally
extending filament containing reinforcing strands which are
pre-impregnated with a curable resin-type matrix to a work piece
while relative movement exists between said work piece and
applicator; said applicator comprising support means, tape supply
means carried by said support means to dispense said tape, cutting
means operatively carried by said support means for cutting said
strands in advance of a preselected location on said work piece to
create terminal ends of said tape coextensive with said preselected
location, means for separating said backing member from said tape
prior to cutting said strands, means for applying said tape to said
work piece, and means for reintroducing the severed portion of the
tape into contact with the backing member at least prior to the
application of the severed strands to the work piece, to thereby
form a final structural member comprised of the strands of tape
when the pre-impregnated tape is cured and removed from the work
piece.
13. The tape application of claim 12, further characterized in that
said applicator comprises photoelectric sensing means including a
radiation active sensory element for detecting said pre-selected
location, and deceleration means operatively connected to said
sensory element and being operable to slowdown the speed of said
relative movement prior to said preselected location.
14. The tape applicator of claim 12, further characterized in that
said photoelectric sensing means includes a radiation active
sensory mechanism for detecting a preselected angle on said work
piece at said preselected location, and means operatively
connecting said sensory element and said cutting means to enable
said strands to be cut at said preselected angle.
15. The tape applicator of claim 14, further characterized in that
said sensory mechanism includes a first radiation active sensing
element initially detecting said preselected angle, and a second
radiation active sensing element capable of being shifted into a
position where said first and second radiation active sensing
elements are aligned with said preselected angle.
16. The tape applicator of claim 14, further characterized in that
said photoelectric sensing means includes a first radiation active
sensing element initially detecting said preselected angle, and a
second radiation active sensing element capable of being shifted
into a position where said first and second radiation active
sensing elements are aligned with said preselected angle, and
stepping motor means for intermittently shifting said second
sensing element until said alignment is achieved.
17. A reinforced composite tape applicator for applying a tape
formed of a plurality of longitudinally extending filament
containing strands on a removable backing member to a work piece,
and which strands are pre-impregnated with a curable resin-type
matrix, said applicator comprising support means, tape supply means
operatively retained by said support means for dispensing said
filament containing tape which has been pre-impregnated with said
curable matrix, pre-heating means for passing radiation into said
pre-impregnated tape during movement of tape past said pre-heating
means to initiate a heating of the resin-type matrix impregnated in
said strands, means for separating said backing member from said
tape prior to passing radiation thereinto, means for applying said
tape to a work piece, and means for momentarily causing contact
between said tape and backing member just prior to placing said
tape on said work piece, to thereby form a final structural member
comprised of the strands of tape when the pre-impregnated tape is
cured and removed from the work piece.
18. The reinforced composite tape applicator of claim 17, further
characterized in that means is provided for shifting said
pre-heating means to a position where substantial radiation is not
directed toward said tape when said tape is not moving with respect
to and past said pre-heating means.
19. A tape applicator for applying a tape formed of a plurality of
longitudinally extending filament containing strands to a receiving
surface during relative movement between said receiving surface and
said applicator, and which strands are pre-impregnated with a
resin-type matrix curable material and located on a removable
backing member; said applicator comprising:
a. support means,
b. tape supply means operatively retained by said support means for
dispensing said filament containing tape therefrom,
c. radiation type pre-heating means located to receive the tape
dispensed from said tape supply means and passing radiation into
said pre-impregnated tape for initiating a heating of the matrix
curable material,
d. motive means for automatically shifting said pre-heating means
to a position where substantial radiation is not directed toward
said tape when the tape is not moving with respect to said
pre-heating means,
e. application means carried by said support means for receiving
said tape and applying same directly to said receiving surface
during relative movement between said tape applicator and said
receiving surface,
f. means carried by said tape applicator for applying radiant
energy directly to said receiving surface,
g. means selectively locatable on said receiving surface to
generate a differential radiant energy response at a predetermined
end position on said receiving surface,
h. sensing means for sensing said predetermined end position with
respect to the application of the tape to the receiving
surface,
i. said sensing means including a radiation active element located
to scan the radiant energy reflected from said receiving surface
and being capable of generating an electrical signal responsive to
receipt of the differential reflected radiant energy response upon
sensing of said predetermined end position,
j. cutting means operable upon receipt of said electrical signal
for automatically severing said tape in advance of said
predetermined position to form a terminal edge which will coincide
with the predetermined end position,
k. said cutting means also including means to form said terminal
edge with a proper angle established by and conformable to said
predetermined end position,
l. means for temporarily separating said tape from said backing
member while said tape is being severed by said cutting means so
that said backing member is not severed therewith,
m. and means for bringing said backing member into contact with
said tape momentarily at said application means and separating same
therefrom after said tape has been applied to said receiving
surface, to thereby form a final structural member comprised of the
strands of tape when the pre-impregnated tape is cured and removed
from the receiving surface.
20. A tape applicator for applying a tape formed of a plurality of
longitudinally extending filament containing strands to a receiving
surface during relative movement between said receiving surface and
said applicator, and which strands are preimpregnated with a
resin-type matrix curable material and located on a removable
backing member; said applicator comprising:
a. support means,
b. drive means for causing relative movement between said receiving
surface and said tape applicator,
c. tape supply means including a supply spool containing said tape
operatively retained by said support means for dispensing said
filament containing tape therefrom,
d. means for positively driving said tape supply means to dispense
tape from said supply spool,
e. radiation type pre-heating means located to receive the tape
dispensed from said tape supply means and passing radiation into
said pre-impregnated tape for initiating a heating of the matrix
curable material during movement of said tape past said pre-heating
means,
f. separation means for removing said backing member from said tape
prior to introduction into a location where said tape receives the
radiation,
g. motive means for automatically shifting said preheating means to
a position where substantial radiation is not directed toward said
tape when the tape is not moving with respect to said pre-heating
means,
h. application means carried by said support means for receiving
said tape and applying same directly to said receiving surface
during relative movement between said tape applicator and said
receiving surface,
i. sensing means for sensing a predetermined end position and a
predetermined angle with respect to the application of the tape to
the receiving surface,
j. said sensing means including a first radiation active element
capable of generating an electrical signal responsive to receipt of
radiation, and initially detecting said predetermined angle,
k. second radiation active sensing means also capable of generating
an electrical signal upon receipt of radiation and being shifted
into a position where said first and second radiation active
sensing elements are aligned with said predetermined angle,
l. stepping motor means for intermittently shifting said second
sensing element until said alignment is achieved,
m. third radiation active sensing means capable of generating an
electrical signal upon receipt of radiation,
n. deceleration means operatively associated with said third
sensing element and with said drive means for decreasing the speed
of relative movement upon detection of said predetermined end
position and in advance of said predetermined end position,
o. cutting means operable upon receipt of said electrical signals
from said first and second radiation active elements for
automatically severing said tape in advance of said predetermined
position to form a terminal edge which will coincide with the
predetermined end position,
p. said cutting means also including means to form said terminal
edge with a proper angle established by and conformable to said
predetermined end position,
q. said separation means also being located to temporarily separate
said tape from said backing member while said tape is being severed
by said cutting means so that said backing member is not severed
therewith,
r. means for bringing said backing member into contact with said
tape momentarily at said application means and separating same
therefrom after said tape has been applied to said receiving
surface, and
s. means for rotating said support means so that said tape is
applied to said receiving surface in a direction opposite to the
direction of relative movement during application of a previous
tape to said receiving surface, to thereby form a final structural
member comprised of the strands of tape when the pre-impregnated
tape is cured and removed from the receiving surface.
21. Apparatus for applying a tape formed of a plurality of
longitudinally extending filament containing strands to a work
receiving surface forming part of a work element, said apparatus
comprising:
a. base means, means for retaining said work element on said base
means,
b. a gantry member movable on said base means,
c. a tape applicator carried by said gantry member and movable
therewith over and past said work element,
d. said tape applicator including support means,
e. tape supply means operatively retained by said support means for
dispensing said filament containing tape therefrom,
f. radiation type pre-heating means located to receive the tape
dispensed from said tape supply means and passing radiation into
said pre-impregnated tape for initiating a heating of the matrix
curable material,
g. application means carried by said support means for receiving
said tape and applying same directly to said receiving surface
during relative movement between said tape applicator and said
receiving surface,
h. means carried by said support means for applying radiant energy
directly to said work receiving surface,
i. means selectively locatable on said receiving surface to
generate a differential reflected radiant energy response at a
predetermined end position on said receiving surface,
j. a radiation active sensing element operatively carried by said
support means for scanning the radiant energy reflected from said
receiving surface and generating an electrical signal responsive to
determination of said differential reflected radiant energy
response at said predetermined end position,
k. cutting means operable upon receipt of said electrical signal
for automatically severing said tape in advance of said
predetermined end position to form a terminal edge which will
coincide with the predetermined end position,
l. and means operatively associated with said cutting means to form
said terminal edge with a proper angle established by and
conformable to said predetermined end position, to thereby form a
final structural member comprised of the strands of tape when the
pre-impregnated tape is cured and removed from the receiving
surface.
22. A tape applicator for applying a tape formed of a plurality of
longitudinally extending filament containing strands to a receiving
surface, said applicator comprising support means, drive means
operatively associated with said support means for causing relative
movement between said tape applicator and said receiving surface,
tape supply means operatively retained by said support means, tape
placement means on said support means for applying said tape to
said receiving surface during relative movement between said
applicator and said receiving surface, sensing means for sensing a
predetermined end position with respect to the application of tape
to said receiving surface, said sensing means including a first
radiation active element capable of generating a first electrical
signal responsive to receipt of radiation upon sensing of said
predetermined end position, deceleration means operatively
associated with said drive means and said first radiation active
element and being operable on receipt of said first electrical
signal for decreasing the speed of relative movement in advance of
said predetermined end position, said sensing means including a
second radiation active element capable of generating a second
electrical response to receipt of radiation upon sensing of said
predetermined end position, and cutting means operable upon receipt
of said second electrical signal for automatically severing said
tape in advance of said predetermined end position to form a
terminal edge which will coincide with the predetermined end
position, said cutting means also including means to form said
terminal edge with a proper angle established by and conformable to
said predetermined end position, to thereby form a final structural
member comprised of the tape when the tape is removed from said
receiving surface.
Description
BACKGROUND OF THE INVENTION
This invention relates in general to certain new and useful
improvements in composite-tape placement heads, and more
particularly, to composite-tape placement heads for direct
attachment to actuating equipment.
In recent years, reinforced plastic composite materials have
achieved increased prominence and have been used in the manufacture
of a variety of products which are normally formed of heavy metals
and other counterpart materials. For example, pipe, motor casings
and various other types of structural members which were formerly
fabricated from the heavy metals are now being produced in the form
of reinforced plastics.
Many of the structural members used in the air frame industry are
presently formed of aluminum and other light weight metals.
However, there has also been a recent transition to the employment
of reinforced plastic components. Conventional filament winding
systems have been employed in the fabrication of these reinforced
plastic components. In order to increase productivity in the
manufacture of these components, resort has been made to the use of
tape application equipment.
However, the extant tape laying equipment is ineffective in many
cases because the filament reinforced tapes are often difficult to
effectively handle due to their modulous of induced rigidity.
Accordingly, the unspooling of a three inch tape, for example,
presents considerable problems in maintaining proper tension on the
tape as it is applied to the work surface. The convolute windings
of the tape tend to expand and unwind in the manner of a released
clock spring. The various tapes presently employed inherently have
some variation in boardiness and tack and the lay down pressure on
the work piece is not variable to adjust for these variations in
the tape.
One of the most serious problems encountered in the use of the
conventional presently available tape heads resides in the failure
of the head to properly sever the tape at a desired location, and
at a pre-selected angle with respect to the work piece.
It is, therefore, the primary object of the present invention to
provide an integrally complete composite-tape placement head for
direct attachment to other actuating equipment.
It is another object of the present invention to provide a tape
placement head of the type stated which can be actuated both in
cooperation with and independently of the host actuating
equipment.
It is a further object of the present invention to provide a tape
placement head of the type stated which is highly reliable in its
operation and which can be used with a wide variety of reinforced
plastic composite tapes.
It is another object of the present invention to provide a tape
placement head of the type stated which includes all of the tape
forwarding, tape-placement, backing-film retrieval, and
tape-cut-off mechanical and drive functions.
It is yet another salient object of the present invention to
provide a tape placement head of the type stated which is
constructed with a high degree of precision and thereby provides an
extremely close dimensional accuracy with minimal tolerances.
With the above and other objects in view, our invention resides in
the novel features in form, construction, and arrangement of parts
presently described and pointed out in the claims.
In the accompanying drawings (6 sheets):
FIG. 1 is a perspective view of a host gantry machine having a tape
placement head of the present invention operatively mounted thereon
and schematically illustrating the application of tape strands to a
work piece;
FIG. 2 is a perspective view of a tape placement head constructed
in accordance with and embodying the present invention;
FIG. 3 is a perspective view of the tape placement head of FIG. 2,
showing the opposite side of the placement head;
FIG. 4 is a side elevational view of the tape placement head,
partially broken away and in section;
FIG. 5 is a horizontal sectional view taken along line 5--5 of FIG.
2 and showing a portion of the cut-off assembly forming part of the
tape placement head;
FIG. 6 is a horizontal sectional view taken along line 6--6 of FIG.
2 and showing a portion of the edge sensing-alignment assembly
forming part of the tape placement head of FIG. 2;
FIG. 7 is a fragmentary vertical sectional view taken along line
7--7 of FIG. 4;
FIG. 8 is a horizontal sectional view taken along line 8--8 of FIG.
2 and showing a portion of the heater assembly forming part of the
tape placement head;
FIG. 9 is a fragmentary sectional view taken along line 9--9 of
FIG. 8;
FIG. 10 is a schematic view illustrating the method of compensating
for tape length when applying at varying angles with respect to the
work piece; and
FIG. 11 is a schematic view illustrating the relationship in terms
of length between a deceleration photocell, cutting mechanism and
applicator roller forming part of the tape placement head of the
present invention.
GENERAL DESCRIPTION
Generally speaking, the present invention relates to a filament
tape applicator (often referred to as a "tape head" or "tape
placement head") which is used on a selected type of host actuating
equipment, such as a gantry machine. The tape placement head is
normally shifted through X and Y coordinate axes through the action
of the gantry machine. In addition, the tape placement head is
constructed so that it can shift along additional axes with respect
to the gantry machine.
The tape placement head of the present invention generally includes
a relatively large major support bracket for removable securement
to the host actuating equipment. A motor is suitably mounted on the
supporting frame and is connected to a drive mechanism for rotating
the tape placement head about a depending flange formed on the host
actuating equipment. The drive mechanism is designed to rotate the
entire tape placement head in a full 180.degree. arc in either
direction. Thus, if tape was being placed upon a work piece during
the movement of the tape placement head in the X axis, the host
actuating equipment would be programmed to automatically stop at
the end of the tape application cycle. At this point in time, th
motor is actuated to rotate the tape placement head 180.degree..
The host actuating equipment would shift the head laterally in the
Y coordinate axis so that a next strand of tape can be placed
adjacent to the previously deposited strand of tape.
Also mounted on the supporting frame is a shaft for removably
receiving a roll of filament type tape such as boron tape. The tape
is secured to a backing film, generally formed of paper, and is
preferably pre-impregnated with a suitable resin curable matrix.
Furthermore, the supply spool is maintained under a proper degree
of tension as the tape strand is paid out from the spool.
A separating mechanism is provided to peel away the backing from
the pre-impregnated tape and the backing is retrieved onto a driven
wind-up storage spool. The relative position of all of the spindles
in the tape placement head have been arranged to provide an
alternate path for the tape-backing, if desired. After the backing
web has been separated from the composite tape, the tape passes
through a cutting mechanism to be hereafter described. The tape is
again brought into contact with the backing web prior to engagement
by a laydown roller. The backing web which is operatively
interposed between the lay-down roller and the tape prevents the
tacky resin matrix from being accumulated on the lay-down roller
and subsequent soiling thereof. Thus, the lay-down roller is
shielded by reutilization of the backing web. In some reinforced
composite tapes, it is not necessary to separate the backing web
from the tape prior to cutting and the backing web would then be
separated from the tape at the lay-down roller.
As indicated previously, the supply spool is driven. The unspooling
of a three inch wide tape, for example, can only be practically
accomplished through physical containment and restraint due to the
modulous induced rigidity. Otherwise, the convolute windings would
tend to expand and unwind in the manner of released clock spring.
The tape which is brought into contact with the backing web and the
lay-down roller is then push-fed against a curving chute which
terminates at the point of tangency with a substrate work
surface.
A cut-off assembly or so-called "shear mechanism" or "shear
assembly" is also mounted on the frame and is pneumatically
operated by paired cylinders. The shear assembly is capable of
cutting a 3 inch wide filament tape through an arc of .+-.
45.degree. normal to the tape center line. The shear assembly is
driven by a stepping motor which is controlled by a complex
edge-sensing mechanism to be hereinafter described. The shear
assembly comprises a combination of a shearing type blade and
teflon anvil. The blade is attached to a fixed shear frame member
and the teflon anvil is attached to a moving platen.
Also mounted on the frame is an edge-alignment sensory assembly
which consists of a pair of photocells mounted on a linkage
mechanism that swings the cells through an arc .+-. 45.degree. from
the tape center-line. The sensing mechansim is driven by and with
the shear mechanism so that the relationship between these two
members is kept constant. As one of the photocells of the
edge-alignment sensory assembly picks up the reflection of its
integral light source from the retro-reflective tape, a signal to
the shear drive motor causes the drive motor to shift the cutting
mechanism in the direction corresponding to the cells' position.
When the second cell is activated, the shear drive mechanism is
stopped and a solenoid valve controlling the shear's cylinders is
energized thereby causing the tape to be severed.
A deceleration photocell is aimed approximately two inches ahead of
the edge-sensing photocells. When this latter cell is activated by
its light beam being reflected from the retro-reflective tape, it
signals the machine to slow to a creep speed. This slow-down
insures that the edge-alignment sensory assembly will have
sufficient time to accurately rotate into position.
Also mounted on a frame is an infrared type of electrical heating
device utilizing a quartz lamp as the heat source and an elliptical
reflector to concentrate the heat in a small band at the focal
point of the reflector, this band being transverse to the direction
of movement of the tape. The quantity of heat is controlled by a
transformer or a rheostat. The heating device is also designed to
rotate away from the tape whenever the tape drive is stopped, in
order to prevent localized heating of the tape, thereby providing
any premature cure of the tape.
DETAILED DESCRIPTION
Referring now in more detail and by reference characters to the
drawings which illustrate a preferred embodiment to the present
invention, T designates a tape placement head which is secured to a
somewhat conventional gantry-type machine in the manner as
illustrated in FIG. 1. In order to more fully understand the
operation of the tape head, a brief description of the gantry-type
machine is provided.
By reference to FIG. 1, it can be seen that the tape head T is
mounted on a gantry machine G having a gantry 1 shiftable along a
longitudinal axis X. Furthermore, the tape head is mounted on a
support plate or carriage 2 which shifts transversely with respect
to a work platform 3 forming part of the gantry machine G. Thus,
the support plate 2 shifts in a transverse or Y axis. The support
plate 2 is also shiftable vertically in a Z coordinate axis. Thus,
the tape head T can be shifted longitudinally with respect to a
work piece W in order to apply longitudinal strands of tape to the
work piece W. In like manner, the support plate 2 is shiftable
transversely so that the tape head T can be shifted in order to
apply a next adjacent strand of tape material. Finally, the support
plate 2 is shiftable vertically in order to locate the tape head T
at a proper distance with respect to the work piece W.
By further reference to FIG. 1, it can be seen that the tape
placement head T is also rotatable in an axis C in order to apply
tape strands to the work piece in an axis which is angularly
displaced with respect to the X or Y axes. Furthermore, the tape
head is shiftable accurately with respect to the Y axis in order to
provide an axis A.sub.2. Finally, while the work piece W is
illustrated as being located on a flat work surface, it should be
recognized that the work piece W may be rotatable along its axis
which is parallel to the X axis in a rotatable coordinate axis
A.sub.1.
By reference to FIGS. 2 and 4, it can be seen that the tape
placement head T integrally includes a bearing retaining ring 4
which forms part of a yoke 11. A support ring 5 is mounted on the
underside of the bearing retaining ring 4 in the manner as further
illustrated in FIGS. 2 and 4 and a drive ring 10 is mounted in
cooperative relationship to the support ring 5 and the retaining
ring 4. The drive ring 10 is provided with an exterior peripheral
ring gear (not shown) and mating with a pinion gear 13 driven by an
electric motor 14, the latter being mounted on a bracket 12, in
order to selectively rotate the entire yoke 11 in 180.degree. arcs.
Thus the entire tape placement head T can be rotated with respect
to the work piece W and with respect to the gantry machine G. A
pair of stops 15 are provided in order to hold the tape placement
head T in position. Furthermore, the stops are provided with
suitable magnetic or other type locking mechansims in order to
maintain a rigid pattern for the tape placement head T, while the
latter is shifting during the application of the tape.
The yoke 11 comprises a pair of oppositely disposed vertically
depending legs 16 which are integrally formed with the support ring
10 in the manner as illustrated in FIG. 2 and the two legs 16 are
connected by a plurality of transversely extending support bars 17
which are welded to or otherwise rigidly secured to the legs 16. At
their lower end, the legs 16 are integrally merged into enlarged
hubs 17' which retain suitable roller bearings 18 for journaling a
transversely extending yoke shaft 19. Thus, it can be seen that the
shaft 19 is pivotal with respect to the legs 16.
Pivoting on the shaft 19 and extending forwardly thereof, that is
in the direction of movement of the tape head T are a pair of
transversely spaced support arms 20 and 20', as illustrated in
FIGS. 2 and 7. Secured to the support shaft 19 and extending
forwardly therefrom is a cast metal side frame 21 which is more
fully illustrated in FIG. 3. It can be seen that the side frame 21
has a forwardly extending horizontally located arm 22 and a
somewhat triangularly shaped cast section 22'.
By reference to FIGS. 2 and 3, it can be seen that the major
portions of the components on the tape head T are carried by the
arms 20 and 20' and the slide frame 21 so that, in essence,
substantially all of the components of the tape head T are pivotal
with respect to the yoke 11 about the yoke shaft 19. A pair of
micro-switches 23 are located on the arm 23 of the side frame 21
and indicate to a central control unit the relative vertical
position of the tape placement head T. In essence, these
micro-switches 23 indicate whether or not the tape head T has been
pivoted upwardly to a shifting position or downwardly to a tape
laying position.
Integrally formed with one of the lowermost transversely extending
support bars 17 are a pair of rearwardly extending clevis forming
brackets 24 for pivotally retaining a hydraulic cylinder 25, the
latter being conventional in its construction and, therefore, not
illustrated in any further detail herein. A piston 26 is operable
by cylinder 25 and secured to the lower end of the piston 26 is a
coupling 27 for pivotal securement to a bracket 28. It can thus be
seen that the bracket 28 is formed with side frame 21 and is
secured to the coupling 27 through a pivot pin 29. Thus, it can be
seen that when the hydraulic cylinder 25 is actuated, the piston 26
will cause the link 27 to shift the cast side frame 21 and the
forwardly extending arm 20 upwardly about the yoke shaft 19,
thereby raising the assembly with respect to the main support yoke
11.
Integrally formed in the upper end of the side frame 21 in an
enlarged hub 30 and journaled in the hub 30 is a transversely
extending reel spindle 31 for supporting a pay-off reel 32. The
reel 32 or so-called "spool" contains wound filament reinforced
composite tape 33 suitably secured to a removable backing 34. As
indicated previously, the tape is of the reinforced composite type
and contains and may be pre-impregnated with a suitable resin
curable matrix. The reel 32 is conveniently removable from the
spindle 31 by means of a rotatable locking assembly 35.
Furthermore, a magnetic brake 36 is secured to the outer end of the
spindle 31 to provide a back tension on the spindle 31 and, hence,
on the pay-off reel 32.
The backing paper may be conveniently formed of any suitable
material which is inert with respect to the tape and any
pre-impregnated matrix and which is conveniently removable from the
tape by means of peeling. For example, the backing may be formed of
paper or a thin flexible plastic material such as polyethylene,
mylar or the like.
The composite tape is generally formed of a series of
longitudinally extending substantially parallel strands of
filamentary reinforced material such as fiberglass, lithium, boron,
quartz or grown whisker crystals, etc. In addition, metal wire may
be interspersed with the filaments in the event that it is desired
to add some type of metallic body to the reinforced structure.
Any of a number of commercially available resin matrix materials
can also be employed for pre-impregnating the tape. The matrix
should be capable at some stage of the process of being liquidified
and softened for a period of time and also should be sufficient to
flow around the filaments forming the tape. In addition, the matrix
should be capable of achieving a rigid stage of a complete
polymerization to become a rigid solid and should also possess
ability to adhere to the reinforced material. Some of the suitable
matrix materials which can be employed for pre-impregnating the
tape are many of the thermoplastic resins such as polypropylene,
polycarbonates, etc. In addition, some thermosetting resins, such
as the polyesters. Many of the phenolics and epoxies can be used as
well.
The pay-off reel 32 is designed to carry either three inch or eight
inch inside diameter cores and a wide number of tape widths. In
order to account for tape reels of different widths, a side plate
37' having a teflon coated inner surface is disposed against the
tape reel. A number of washers can also be disposed on the reel
spindle 31 between the side plate 37 and the locking nut assembly
35.
The composite of the tape 33 and the backing 34 is then passed
between a pair of tape guides 38 and trained through an idler pinch
roller 39 and a drive roller 40 in the manner as illustrated in
FIGS. 2 and 4. The combination of the drive roller 40 and the idler
pinch roller 29 provides a means for feeding the tape through the
system at a preselected rate. The pinch roller 39 is rotatably
secured to a pivotally mounted arm 41 which is biased toward the
drive roller 40, by means of a set screw mechanism 42 in order to
maintain a proper pressure between the tape backing 34 and the
drive roller 40. A suitable drive motor 43 is mounted on the side
frame 21 for driving the drive roller 40. An overrunning clutch
(not shown) may be fitted between the drive roller 40 and the motor
43 to allow the tape to be unspooled at a rate faster than the
motor drive speed in such manner that the machine travel rate
determines the tape speed during the actual tape laying
operation.
The backing web 34 is separated from the tape 33 on the underside
of the drive roller 40 in the manner as illustrated in FIGS. 2 and
4 and the backing web 34 is then trained around an idler roller 44,
the latter being secured to a shaft 45 journaled on the side frame
21. As indicated previously, in many cases it is not necessary to
separate the tape from the backing web, in which case the idler
roller 44 would not be employed.
The tape 33 which has been separated from the backing web 34 is
then passed along a guide plate 46 and into tape cutting mechanism
47 and a heating mechanism 48 in the manner as illustrated in FIGS.
2 and 4. The tape cutting mechanism 47 and the heating mechanism 48
will be hereinafter described in more detail.
Finally, the tape 33 is again brought into facewise engagement with
the backing web 34 along the annular surface of a tape placement
roller or so-called "applicator roller" 49, the latter being
journaled on a transversely extending roller shaft 50 and which is,
in turn, secured to the extending arms 20, 20'. The tape placement
roller 49 is pneumatically inflated to provide an adjustable and
variable pressure area. Secured to the side frame 21 and being
connected to the extending arm 20 is an adjustable spring loading
device 51 enabling an operator to adjust a roll-down pressure on
the roller 49. This mechanism provides for a type of spring
suspension of the tape placement roller 49 to enable compliance
with variations in a complex surface. The spring loading device 51
is more fully illustrated in FIG. 7 and is described in more detail
hereinafter. It should be observed that the impregnated tape 33
does not contact any portion of the tape placement roller 49 since
the backing web 34 is interposed between the tape 33 and the roller
49. Furthermore, it can be observed that as the tape head T travels
in the direction of movement of the arrow, reference being made to
FIG. 4, the tape will be applied to the work surface W.
The backing web 34 is trained around a take-up spool 52 which is
mounted on a powered spool shaft 53, the latter being journaled on
the side frame 21. The spool shaft 53 is driven by means of a
high-slip motor 54 which provides a constant tension on the backing
web 34 and with varying speed. It should be observed that the
take-up spool 52 is retained on the shaft 53 by means of a locking
nut 55 for convenient removal of the spool 52.
By reference to FIGS. 2 and 4, it can be seen that a guide shoe 56
clamps the tape 33 along with the backing web 34 to the tape
placement roller 49 prior to retraction of the entire tape laying
head T. With this mechanism, it is possible to maintain the tape
position during the "turn around" phase of the tape placement
operation. It can be seen that the guide shoe assembly 56 is
provided with an accurately shaped shoe surface 57 conforming to
the surface of the tape placement roller 49. Furthermore, the guide
shoe assembly 56 is pneumatically operable by means of a pneumatic
cylinder 58.
By reference to FIG. 1, it can be seen that the tape laying head T
travels with the carriage 2 along the axis X during the application
of the tape 33 to the work piece W. As the tape is applied to the
surface of the work piece W, it is severed in such manner that the
terminal end of the severed section is coincident with the
transverse margin of the work piece W. At this point, the gantry 1
is programmed to stop its shifting movement and the tape heat T
will rotate for a 180.degree. arc so that another strand of tape
can be laid adjacent to the previously deposited strand of tape on
the work piece W. Furthermore, the carriage 2 will be shifted
transversely in order to properly locate the applicator roller 49
with respect to the work piece W.
The tape head T includes an edge-alignment sensory assembly 59
which, in part controls the movement of the tape head T. This
edge-alignment sensory assembly is capable of detecting the
terminal edge of the work piece W in advance of that edge during
the movement of the entire tape head T. Thus, the tape head T will
stop its advancing movement at a prescribed location, and is
signaled to stop its advancing movement in advance of the
prescribed location. In addition, the edge-alignment sensory
assembly controls the cutting mechanism 47 so that the edge of the
tape 33 is severed with an edge trim conforming to a peripheral
edge of the work piece W.
The edge-alignment sensory assembly includes a deceleration
photocell 60 which is secured to a pivotally mounted bracket 61 in
the manner as illustrated in FIGS. 2 and 4. In actual operation, a
retro-reflective tape (not shown) is deposited on the edge of the
work piece W, or preferably spaced from the edge of the work piece
W, and is capable of being sensed by the photocell 60. The
retro-reflective tape will have a substantially different surface
emissivity than the work piece W so that the photocell 60 will be
capable of detecting a marked change in surface emissivity - as
being the difference between the dark impregnated tape and a white
strip of relfective tape. Thus, when the photocell 60 is actuated
by its light beam reflected from the retro-reflective tape, it
signals the tape head T and the controlling mechanism (not shown)
for the gantry machine G to reduce the speed of movement of the
carriage. This reduction in speed insures that the edge-alignment
sensory assembly will have sufficient time to rotate into position
accurately, in a manner to be more fully described in detail
hereinafter.
The edge-alignment sensory assembly 59 also includes a pair of
photocells 62, 62' mounted on a linkage mechanism 63 which swings
the photocells 62, 62' through a .+-. 45.degree. arc with respect
to the centerline of the tape being deposited. The linkage
mechanism 63 and the photocells 62, 62' are more fully illustrated
in FIG. 6. The link mechanism is biased rearwardly, reference being
made to FIG. 6, by means of a compression spring 64 which bears
against a flat plate 65. The plate 65 is connected to the link
mechanism 63 by means of a pair of spaced rods 66 which extend
through axial bearings 67. Furthermore, an adjustment screw 68 is
provided for regulating the degree of bias rearwardly on the
linkage mechanism 63.
It can be seen that the photocells 62, 62' are mounted on a flat
cross bar 69 which is secured to a mounting plate 70, the latter in
turn being secured to a pair of shiftable links 71, 72. Finally,
the mounting plate 66 is shifted by means of a bar 73 connected to
the rods 66. By further reference to FIG. 6, it can be seen that
the links 71, 72 are secured to stepping links 74, 75,
respectively, which are in turn shifted through an anchor 76 on a
vertical drive shaft 77. The drive shaft 77 is in turn driven
through a gear mechanism 78 by means of a stepping motor 79, the
latter being illustrated in FIGS. 2 and 5. The link structure 63
with the attendant links 71, 72 and the drive link 73 all form a
stirrup structure so that the photocells 62, 62' essentially ride
on an idle cross bar. In this manner, they are free to rotate .+-.
45.degree. parallel to the work surface.
When either of the photocells 62, 62' detects a marked change in
surface emissivity -- as being the difference between the dark
pre-impregnated boron (or graphite) tape and a white skirt or strip
of reflective tape on the work piece W, the photocells will, in
essence, hold to the colored change line. This allows the other of
the photocells to swing forward. Thus, if the photocell 62' first
detected the colored change line, represented by the demarcation
between tape and the work piece W, the other photocell 62 would
swing forward through the action of the stepping motor 73. Thus, as
the tape head T continually moves forward, the photocell 62 will
continually shift causing the link mechansim 63 to rotate the
photocells 62, 62' until both photocells are in complete alignment
with the edge of the tape 33.
By further reference to FIG. 4, it can be seen that the photocell
60 is located so that it detects the position of a point during the
movement of the tape head T toward that point and prior to the time
that the tape head T reaches that particular point. Thus, in the
case of the present invention, the photocell 60 will be the first
of the photocells to detect the presence of the retro-reflective
tape. In normal practice, it is desirable to place the tape
approximately 2 inches from and in parallel relationship to the
edge of the work surface. These relationships are more fully
illustrated in FIGS. 10 and 11. Thus, if the tape placement head
were moving in a path such as that designated as Y.sub.1 in FIG.
10, the tape placement head T would be moving toward the work piece
edge designated as Z.sub.1. The photocell 60 would detect the
retro-reflective tape Z.sub.2 which is fixed approximately 2 inches
from the edge of the work surface Z.sub.1. As the photocell 60
detects the retro-reflective tape Z.sub.2, a signal is generated to
slow-down the movement of the tape head T. Furthermore, it can be
seen that since the tape head T is moving in a direction completely
perpendicular to the edge of the work surface Z.sub.1 and the
retro-reflective tape Z.sub.2, that the photocells 60, 62' will not
change their relative position. Accordingly, when the two
photocells 60, 62' contact the retro-reflective tape Z.sub.2, a
signal will be generated to initiate the tape cutting mechanism 47.
At this point the tape 33 will be severed.
It is to be noted that these time-distance relationships are fixed,
but yet are adjustable in the tape head T. For example, when the
applicator roller 29 is located at the position illustrated in FIG.
11 and a cutting signal is generated, the tape 33 will be severed.
The distance between the severed edge of the tape 33 and the point
of contact of the applicator roller 49 (designated as S) is equal
to the distance between the this point of contact S of the roller
49 and the work piece edge Z.sub.1 (distance designated as
X.sub.1). Furthermore, it is to be noted that the cutting signal is
generated when the photocells 62 and 62' are aligned with work
piece edge and both detect the line Z.sub.2, as illustrated in
FIGS. 10 and 11.
It can be seen that if the tape placement head T was moving along
the path Y.sub.2 as illustrated in FIG. 10, then a somewhat
different time relationship is created. When the tape placement
head T is moving in the path Y.sub.2 the photocell 60 will detect
the retro-reflective tape Z.sub.2 generating a signal to slow-down
the movement of the tape head. However, since the tape placement
head T is moving in an angulated path the distance between Z.sub.1
and Z.sub.2 in the direction Y.sub.2 is not equal to the distance
between Z.sub.1 and Z.sub.2 in the direction Y.sub.1. The tape
placement head T of the present invention compensates for this
change of distance. Thus, the two photocells 62 and 62' will not
contact the retro-reflective tape Z.sub.2 at the same point in
time. The first photocell 62' will contact the retro-reflective
tape Z.sub.2. This will cause the other of the photocells 62 to
shift around through the action of the link mechanism 63 as
illustrated in FIG. 6. However, it is to be noted that the link
mechanism 63 actually extends forwardly in order to compensate for
the additional distance between Z.sub.1 and Z.sub.2 as a result of
the tape head moving in the path Y.sub.2.
Accordingly, when the photocell 62' detects the retro-reflective
tape Z.sub.2, the link 71 will remain stationary but photocell 62
will shift forwardly through the action of the link 72. It is to be
noted that the link 72 is movable through the stepping link 74 by
the action of the anchor 76. The actual point of rotation will
occur about the point of connection between the link 71 and the
mounting plate 70. Furthermore, it can be observed that the entire
linkage mechanism 63 shifts forward. The drive link 73 actually
shifts forwardly through the action of the rod 66 moving through
the axial bearings 67. Furthermore, this forwardly moving action
occurs against the action of the compression spring 64. Thus, it
can be seen that the photocells 62, 62' not only compensate for the
angle between the direction of movement of the tape head T and the
edge of the work surface, but actually compensate for a variance in
distance between the edge of the work surface Z.sub.1 and the
retro-reflective tape Z.sub.2 caused by the angle of movement of
the tape head T. It can also be observed at the end of the work
cycle, that the two photocells 62, 62' will be shifted back to
their normal positions, as illustrated in FIG. 6, and, furthermore,
the entire assembly will be shifted to the right by the action of
the compression spring 64.
In addition, it can be seen that as a result of the tape head T
movement in the path Y.sub.2, an additional distance of X.sub.3 is
generated in FIG. 11. Accordingly, when the two photocells 62, 62'
shift in order to match the edge of the work surface Z.sub.1, they
will be extended for a distance X.sub.3.
The tape cutting mechanism 47 is more fully illustrated in FIG. 5
and generally comprises a frame 84 which is rotated through a .+-.
45.degree. arc by means of the stepping motor 79. It can be seen
that the frame 84 is secured to a shaft 85 supported by roller
bearings 86 and is driven through a pair of pulleys 87 and a drive
belt 88. Thus, it can be seen that when the stepping motor shifts
the photocells 62, 62' to become aligned with the retro-reflective
tape, the stepping motor 79 will also shift the shear frame 84.
Rigidly secured to one end of the shear frame is a blade 89 and
which is engagable with a similar blade 90, the latter being
secured to a slideable plate 91. By further reference to FIG. 5, it
can be seen that the plate 91 is shiftable along a pair of guides
92 forming part of the frame 84 and is powered by means of a pair
of pneumatic cylinders 93, the latter being secured to the frame
84. Thus, it can be seen that the cutting blades 89, 90 are
pneumatically operated by the paired cylinders 93. Furthermore,
this mechanism is capable of cutting a three-inch wide tape through
an arc of .+-. 45.degree. with respect to the tape centerline. The
blade 89 actually serves as a type of anvil and is preferably
formed of teflon. The blade 90 which is shiftable with respect to
blade 89 serves as a crushing type of blade.
Thus, the edge-alignment sensory assembly also drives the tape
cutting mechanism 47. As one of the photocells 62, 62' pick up the
reflections of its integral light source from the retro-reflective
tape, the motor 79 is actuated to operate in a direction
corresponding to the cells' position. As the shear frame 84
rotates, it also drives the link structure 63 to the angle of the
retro-reflective tape. When the second photocell is activated, the
stepping motor 79 stops the rotation of the shear frame 84 and also
thereafter energizes a solenoid valve (not shown) which controls
the cylinders 93 to cause the tape to be severed.
By further reference to FIG. 7, it can be seen that the spring
loading device 51 is designed to provide an adjustable spring
loading pressure on the applicator roller 49. The spring loading
device 51 essentially cooperates with the side frame 21 and the arm
20 in the manner as illustrated. The spring loading device 51
generally comprises a bracket 94 which is welded or otherwise
secured to side frame 21 in the manner as illustrated. In addition,
the bracket 94 has a flange 95 which extends through a slot 96
formed within the arm 201. Furthermore, the bracket 94 has a lower
flange 97 which also extends outwardly from the side frame 21 and
the flanges 95, 97 carry adjusting screws 98, 99, respectively.
Both of the adjusting screws are capable of bearing against a
spring bias 100 which is biased downwardly through the action of
the spring 101. Thus, it can be seen that the applicator roller 49
is carried by the arms 20, 20' and partially held by the side frame
21. However, the roller 49 is shiftable to a slight degree with
respect to the side frame 21 so that it is capable of compensating
for variance in the work surface W. The degree of bias tension
maintained on the roller 49 is adjusted by the upper screw 98 with
a possible degree of lowermost movement of the applicator roller 49
regulated by means of the screw 99. The desired load pressure
maintained on the applicator roller 49 is determined by the many
factors which affect the tape lay-down characteristics. For
example, a soft, resin-rich tape would require less roller load for
a good adherence than would be required for a dryer tape.
The heating mechanism 48 is more fully illustrated in FIG. 8 of the
drawings and generally comprises a quartz lamp 104 which is located
within a frame 105. The frame 105 is rotatably mounted on a shaft
106 and operates a pair of microswitches 107, 108 by means of a cam
109 located on an extension of the shaft 106. In like manner, the
extension of the shaft 106 is secured through a coupling 110 to an
electric motor 111. The frame 105 is located so that the quartz
lamp 104 provides an infrared type of heat source and the frame 105
concentrates the heat in a 0.06 to 0.09 inch wide band at the focal
point of the reflector. The quantity of heat is controlled by a
console mounted transformer or rheostat (not shown). At any point
in time when the tape 33 stops moving in the tape head T, the
electric motor 111 is energized to rotate through shaft 106 the
frame 105 and, hence, the quartz lamp 104 away from the tape 33 to
prevent localized heating of the tape and thereby avoiding a
premature cure of the tape.
It should be understood that changes and modifications in the form,
construction, arrangement and combination of parts presently
described and pointed out may be made and substituted for those
herein shown without departing from the nature and principle of our
invention.
* * * * *