Note: Descriptions are shown in the official language in which they were submitted.
CA 02366091 2001-12-21
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for inserting hooks
into a tape.
In horticulture it is now becoming common practice to provide an environmental
control
for a crop growing area through the use of a curtain located above the crop.
The curtains are
adjustable so that they may be retracted or deployed or maybe replaced with
alternative materials
to affect the climatic conditions to which the crop is subjected. These
curtains may be used
internally within an existing greenhouse structure or externally on a
structural framework as a
greenhouse roof.
The curtains are suspended from sets of parallel wires by hooks inserted into
the curtain
material. The hooks can slide along the wires under control of a motor or
similar device so that
the position of the curtain within the structure can be adjusted.
To ensure satisfactory operation of the curtain, the hooks must be carefully
aligned
between adjacent rows of hooks and must be uniformly spaced along each of the
wires. The
hooks must also be capable of withstanding the significant forces that may be
imposed upon the
curtain and therefore are of relatively robust constructions, typically molded
from plastics
material. The hooks must also be designed such that once they are secured to
the material they
are not detached or torn from the material.
The traditional way of securing the hooks to the material is by manually
inserting the
hook directly into the weave of the material. This, however, requires great
care in alignment and
is labor intensive. An alternative approach is to secure the hooks to a tape
and sew the tape to
the material. Such an arrangement is shown in published PCT application No. CA
98-00705
in which a sewing machine is provided that permits the sewing of tape on to a
fabric in a
controlled and carefully aligned manner. However, the insertion of the hooks
to the tape is still
time consuming and still needs to be performed in a controlled manner to
ensure uniform spacing
and pleating of the hooks.
It is therefore an object to the present invention to provide a method and
apparatus to
permit insertion of the hooks into a tape and overcome the above noted
disadvantages.
CA 02366091 2001-12-21
According to the present invention there is provided a method of inserting a
hook having
a open bight terminating at a free end into a tape comprising the steps of
moving the tape along a
predetermined path to a hook insertion station, folding the tape to present a
pair of oppositely
directed surfaces orthogonal to the predetermined path, positioning a hook
with its free end
aligned with and generally normal to one of the oppositely directed surfaces,
engaging the hook
to move the hook toward the tape such that the free end pierces the oppositely
directed surfaces
of the tape, and unfolding the tape to secure the hook within the bight.
Preferably, the hook is rotated to move the fold into the bight of the hook.
Alternatively, the hook is closed by abutment with a stop and application of a
force in the
direction of insertion.
Embodiments of the invention will now be described by where of example only
with
reference to the accompanying drawings in which.
Figure 1 is a general schematic representation of a curtain system
Figure 2 is a perspective view of a tape and hook used in the curtain system
of Figure 1.
Figure 3 is a section on the line 3-3 of Figure 2.
Figure 4 is a schematic representation of the sequential steps involved in
inserting the
hook into the tape to obtain the arrangement shown in Figure 3.
Figure S is a plan view of the general arrangement of the machine illustrating
schematically in Figure 4.
Figure 6 is a side view of the machine shown in Figure 5.
Figure 7 is a view on an enlarged scale of a portion of the machine shown in
Figure 6.
Figure 8 is a plan view on the line 8-8 of Figure 7.
Figure 9 is a view on the line 9-9 of Figure 8.
Figure 10 is an end view of the hook insertion mechanism shown schematically
in Figure
4.
Figure 11 is a side view of mechanism shown in Figure 10.
Figure 12 is a plan view of the mechanism shown in Figure 10.
Figure 13 is a front view of an alternative embodiment of hook,
Figure 14 is a side view of the hook of figure 13,
Figure 15 is a plan view of an alternative embodiment of hook insertion
apparatus,
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CA 02366091 2001-12-21
Figure 16 is an end view of the apparatus of figure 15,
Figure 17 is a side view of the apparatus of figure 15,
Figure 18 is an enlarged view of a portion of the apparatus seen in figure 17,
Figure 19 is a side view of figure 18 showing alternative positions of the
components
thereof,
Figure 20 is an enlarged view of a portion of the apparatus seen in figure 19,
and
Figure 21 is an enlarged view of a further portion of the apparatus seen in
figure 19.
Referring therefore to Figure 1 a greenhouse structure 10 includes spaced
structural
gables 12 defining a sagitated roof line and supported on posts 14. Wires 16
extend between the
gables 12 and support a curtain 18. The curtain 18 is secured to the wires 16
by hooks 20 which
slide along the wires 16 to allow retraction or deployment of the curtain and
thereby control the
environment within the greenhouse structure 10. The general arrangement of
greenhouse 10 is
well known in the art and therefore need not be described fiwther at this
time.
Referring to Figure 2 and 3, the hook 20 is secured to the curtain 18 through
the
intermediary of a tape 22. The hook 20 is formed with an open bight 24 to
accommodate the
tape 22. The bight is defined between a pair of legs 26, 28 interconnected by
cross member 30.
The free end of the leg 28 is formed as a barb 32 to retain the leg 28 within
the tape after
insertion and the free end of the leg 26 is formed with an open aperture 34 to
receive the cable
16. Again the form of the hook is known and the exact details thereof may vary
from installation
to installation.
A hook insertion apparatus shown in Figures 5 through 12 is utilised to insert
the hook 20
within the tape 22 and the steps of the process are illustrated schematically
in Figure 4. Prior to
describing the detailed operation in the machine, the overall arrangement of
the machine is best
appreciated from a review of the sequential steps set out in Figure 4.
Referring therefore to
Figure 4(a) the hook insertion apparatus generally designated 50 includes a
tape feed and support
station 52 and tape folding m~hanism 54. Hooks 20 are delivered to the support
station 52
through a hook delivery mechanism, indicated generally at 56 on Figure 5.
Referring again to
Figure 4(a) a hook insertion mechanism 58 includes a jaw 60 secured at one end
of an operating
arm 62. The operating arm 62 is slidably and pivotally supported in a guide 63
and positioned
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CA 02366091 2001-12-21
within the guide by actuator 66. Lateral displacement of the arm 62 is
controlled by an actuator
68 operating through a cam 70 secured to the actuator and a follower 72
secured to the arm 62.
In the initial condition shown in Figure 4 (a) the hook 20 is delivery to the
support
station 52 with the tape supported by the station in a planar position. The
folding mechanism 54
is retracted and the jaw 60 open so that the hook is free to be positioned
adjacent the station.
As an initial step, the folding mechanism 54 is lowered to fold the tape 22
back on itself
within a slot provided in the folding station 52 and orientated along the
direction of fed of the
tape. At the same time, the jaw 60 is closed within the aperture 34 in the
hook 20 so that the
hook 20 and arm 62 are interconnected. In this position, the barb 32 is facing
one of a pair of
oppositely directed surfaces, 23,25 on the tape 22.
To move the hook through the tape 22, the actuator 62 is operated to swing the
arm 62
within the guide 63 to the position shown in Figure 4 (c). The actuator 68
operates upon the cam
70 to move the roller 72 and thereby the arm 62 to the inclined position. The
pivotal connection
between arms 62 and actuator 66 accommodates the inclination of the arm 62.
The hook 20 is
thus pulled through the tape so as to project through both of the oppositely
directed faces of the
tape. After insertion, the hook, as shown in Figure 4 (c) it is rotated to the
position in Figure 4
(d) by operation of the actuator 66. The actuator 66 pulls on the arm 62 to
move it along the cam
surface of the cam 70 and thereby lower and rotate the end 34 of the hook 20.
Thereafter, the
fold mechanism is retracted and the tape advanced so as to open the fold and
nest the tape within
the bight 24 of the hook 20. The jaw 60 is released and returned to the
condition as shown in
Figure 4(a) for the next hook 20.
The details of the mechanism are shown more fully in Figures 5 through 12.
Referring therefore to Figure 5, the hook delivery mechanism 56 includes a
hopper 100
sloping downwardly and inwardly to an outlet 102. A spiral picker mechanism
104 is located
below the aperture 102 to receive and orientate the individual hooks 20 and
deliver to them chute
106. The hooks delivered to the chute 106 are all oriented with the barb 28
pointing in the
direction of travel indicated by the arrow A and uppermost. The chute 106
delivers the hooks to
the support station 52 through which the tape 22 is advanced. As can best be
seen in Figure 6,
tape 22 is fed from a reel (not shown) across the support station 52 and
around the outer
periphery of a drive wheel 108. The drive wheel is rotatable about a generally
horizontal axis
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CA 02366091 2001-12-21
driven by a motor 110 through a clutch and brake mechanism (Figure 5). A pinch
wheel 112 is
positioned adjacent the periphery of the drive wheel 108 to cause tape 22 to
engage with the
drum and be advanced by it. The clutch and brake mechanism transmits the drive
from the
motor 110 to the wheel 108 intermittently so that the movement of the tape
past the fold station
52 is likewise intermittent. Movement of the tape 22 through the folding
station is also controlled
by a retractable clamp 132 (Figure 6) which has a shoe 134 moveable by an
actuator 136. The
shoe can be moved toward the platen 114 to engage the tape 22 and inhibit
continued movement
induced by the drive wheel 108.
The support station 52, as shown in Figures 6 through 9 has a platen 114 with
an upper
surface 116 to support the tape 22. The platen 114 has an elongate slot 118
located immediately
below a blade 120. The blade 120 is dimensioned to fit within the slot 118 and
includes a notch
122 aligned with the chute 106 of the hook feed mechanism. The blade 120 is
secured to the rod
of an actuator 124 which can be operated to lower or raise the blade 120. A
ramped surface 121
is provide at each end of the slot 118 to facilitate the smooth transition
from a flat to folded
configuration.
A releasable stop 126 is located on the platen 114 adjacent the chute 106 and
is operative
to control the flow of hooks 20 along the chute and to the station 52. The
platen 114 has an
elongate cavity 128 (Figure 9) intersecting the slot 118 and aligned with the
notch 122. The
cavity 128 is dimensioned to snuggly receive one of the hooks 120 and to be
maintained in
position by a stop 130 provided on the upper end of arm 62 as will be
described more fully
below.
The hook insertion mechanism is best shown in Figures 10, 11, and 12. The
operating
arm 62 is of square cross section and is supported between a pair of side
plates 150. The arm
162 carnes a pair of rollers 154 at its lower end which are slightably
received in a slot 156
formed in respective ones of the side plates 150, 152. The side plates 150,
include a cantilevered
extension 158 that are provided with a pair of mounting lugs 160 projecting
toward one another.
The lugs 160 engage a mounting boss 162 formed on the end of an actuator 164.
The actuator
164 is connected to the cam 70 provided by a slide block 166 (Figure 12) which
in turn has a pair
of cam plates 168 projecting forwardly within the side plates 150, 152. Each
of the cam plates
CA 02366091 2001-12-21
includes a cam track 170 of generally cartoid shape defining a limit of
lateral and longitudinal
movement. The follower 72 is provided by a pair of rollers 172 secured to
opposite sides of the
arm 62 and received within respective ones of the cam track 170. The lateral
position of the arm
62 relative to the side arms 150, is thus controlled by the actuator 64 and
limited by the rollers
172 acting within the cam tracks 170. The vertical position of the arm 62
within the side plates
is controlled by the actuator 66 located at the lower end of the arm 62 and
secured to the arm by
a pin 176. A similar pin 178 secures the actuator 66 to the side arm 150 to
permit pivotal
movement of the arm 62 relative to the side arms under the control of the
actuator 164.
The jaw assembly 60 is located at the opposite end of the control arm 62 and
comprises a
crank 180 pivotally secured at 182 to the arm 62. The opposite end of the arm
180 includes a pin
184 that is received within the stop 130 formed at the tip of the arm 62. An
actuator 186 acts
between the arm 62 and the crank 180 to open and close the jaw assembly 60. In
the open
position, the end 34 of the hook 20 can be positioned against the stop 130 so
that the aperture 34
in the end of the hook 20 is aligned with the pin 184. Upon extension of the
actuator 186, the
crank 180 closes to bring the pin 184 into the aperture and thereby secure the
hook 29 to the arm
62.
In order to insert a hook 20 into the tape 22, the tape 22 is first advanced
by the drive
wheel 108 so that the location on the tape is to receive the hook and is
positioned at the support
station 52. The drive from the motor 110 is disconnected and the clamp 136
actuated to inhibit
further movement between the tape 22 and platen 114. The blade 120 is then
lowered so as to
fold the tape about the blade 120 into the slot 118 and provide the pair of
oppositely directed
surfaces 23,25. At this position, which corresponds to (b) in Figure 4, the
tip of the barb 32 of
the hook 20 is aligned with the notch 122 and with the arm 24 of the hook 20
below the blade
120.
With the hook 20 secured to the arm 62, the actuator 164 is operated to
displace laterally
the cam plate 168 and thereby pivot the arm 62 about the roller 154 between
the side plates 150.
This action forces the barb 32 through the folds of the tape 22 in the region
overlying the notch
122 so as to pierce the folds of the tape 22 and pulls the hook 20 through the
tape 22 to the
position shown at Figure 4 (c).
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CA 02366091 2001-12-21
The actuator 164 may then be returned to its original position and the
actuator 174
retracted so as to move the arm 62 vertically downwardly between the side
plates 150, 152. This
downward movement causes the roller 172 to roll along the cam face and thereby
progressively
return the arm 62 to a vertical position at the apex of the cam surface 170.
During this
movement, the hook is rotated within the tape to the position shown at Figure
4 (d).
The actuator 186 is then retracted to release the hook from the arm 62 and the
clamp 134
released and the clutch on motor 110 engaged to advance the tape around the
drive drum 108.
As the tape 22 is advanced, it exits the slot 118 and unfolds. As it unfolds,
it settles in the bight
24 of the hook 20. The tape is then advanced until the next position at which
a hook 20 is
required, at which time the clamp 132 again inhibits further movement of the
tape. The stop 126
is withdrawn to allow a further hook 20 to be advanced from the chute into the
chamber 128 and
against the stop130 in a position for insertion. The actuator 174 extends to
return the arm 62
vertically upwardly to the start position ready to complete a further cycle.
It will be seen therefore that the apparatus of figures 5 to 12 enables a hook
to be inserted
at regular predetermined intervals without manual intervention. The tape with
the hooks inserted
may then be attached to the curtain 18 as described in the above referenced
PCT application.
A further embodiment of the hook insertion apparatus 50 is described below in
which like
components will be identified with like reference numerals with a suffix "a"
added for clarity.
The apparatus SOa of figures 15 to 21 is used to insert the hook 20a shown in
figure 13 and 14.
The hook 20a is similar in function to the hook 20 but provides a closure for
the leg 28a. Further
details of the hook 20a may be obtained from PCT publication WO 00/55513, the
contents of
which are incorporated herein by reference. Briefly however, to the extent
necessary to
appreciate the operation of the apparatus SOa, the leg 26a is formed with an
enlarged head 180
defining the aperture 34a. The connection of the cross member 30a to the leg
26a provides a
degree of resilience to permit the leg 28a to move from the open position
shown in solid line in
figure 13 to the closed position shown in ghosted outline. A groove 182 is
formed in the side
face 184 of the head 180 that opens in to a broader channel 186. The groove
182 is dimensioned
to receive the leg 28a and the channel 186 the barb 32a.
After insertion of the hook in the tape 22a, the cross member 30a is flexed to
bring the
barb 32a in to alignment with the channel 186 sa that the leg may be inserted
in to the groove
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CA 02366091 2001-12-21
182. Release of the force on the cross member 30a allows the barb to engage
the end of the
channel 186 and retain the leg 28a in a closed or locked position. If
preferred, an undercut may
be provided at the transition from groove 182 to channel 186 to retain the
barb 32a.
The apparatus used to insert the hooks SOa is shown in figures 15 to 21. Hooks
20a are
retrieved from a hopper 100a, and delivered to a chute 106a with the barbs 32a
uppermost. The
tape 22a is delivered to the platen 114a and folded within the slot 118a by
blade 120a as
described above. To insert the hooks 20a, a pusher mechanism 200 is utilised
that is located
parallel to but spaced from the chute 106a. Hooks 20a are transferred from the
chute 106a to the
pusher mechanism 200 by a shuttle 202 (figure 18).
The shuttle 202 includes a carriage 204 of generally channel section and
configured to
support a hook 20a on a base 206 between a pair of sidewalk 208. The carriage
204 corresponds
to the profile of the chute 106a and is interposed between the chute 106a and
a stop surface that
limits movement of the hooks in the chute. The carriage 204 is mounted on a
rod 212 of an
actuator 214disposed generally parallel to the direction of feed of the tape
22a so as to be
1 S movable between the pusher mechanism 200 and the chute 106a..
The pusher mechanism 200 is upwardly inclined relative to the chute 106a and
is shown
in detail in figures 19 and 20. The pusher mechanism 200 has a base 220 with a
slide plate 222
secured to it to define an axis of movement generally normal to the direction
of the tape feed. A
pair of slide blocks 224 are mounted at spaced intervals on a sliding plate
226 and engage the
slide plate 222 to allow relative sliding movement between the plates 222 and
226. The sliding
plate 226 is attached to a piston rod 228 of a hook insertion actuator 68a and
the cylinder 230 is
secured to the base 220. An adjustable stop 232 is provided on the base 220 to
limit the travel
between the sliding plate 226 and the base 220.
A shoe 234 is mounted on the sliding plate 226 and has a notched outer end 236
defined
by converging flanks 238,240. As can be seen in figure 19, the flanks 238,240
are configured so
that when the lower flank 238 supports the head 180, the upper flank 240
contacts the
intersection of the crossmember 30a and leg 28a.
An anvil assembly 242 is positioned on the opposite side of the blade 120a to
the pusher
mechanism 200. The anvil assembly 242 includes an anvil 244 with a strike face
246 conforming
to the nose of the head 180. The anvil 244 is mounted on a frame 248 and is
adjustable in a
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CA 02366091 2001-12-21
vertical direction by a pair of bolts 250. The anvil 244 is secured in
position by a bolt 252. The
orientation of the hock 20a during movement of the shoe 234 is maintained by a
pair of guide
pins 254 that pass through holes in the anvil 242 and form the piston mds of
actuators 256. The
actuators 256 are mounted side by side on a bracket 260 cantilevered from the
platen 114a and
the pins 254 are spaced apart so as to pass to either side of the hook 20a
mounted on the shoe
234. The pins 254 are positioned vertically to overlap the nose of the head
180 as it passes
below the tape during insertion and are retrievable by the actuator 256 after
insertion to allow
subsequent movement of the tape.
In operation, the hooks 20a are fed from the hopper 100a to the chute 106a.
The shuttle
202 is positioned by the actuator 214 with the carriage 204 aligned with the
chutel Oda. The hook
20a is supported in the carriage 204 which is transferred by the actuator 214
into alignment with
the pusher mechanism 200. The carriage 204 is positioned adjacent the shoe 234
and presents the
hook 20a in the proper orientation to the notched outer end 236.
With the hook 20a in position in the pusher mechanism 200, movement of the
drive
wheel 108a is interrupted and clamp 132a operated to hold the tape 22a
stationary on the platen
114a. The blade 120a is lowered to fold the tape 22a in to the slot 118a and
present one of the
oppositely directed faces to the insertion mechanism 200. The pins 254 are
extended toward the
blade 120a to provide a guide for the hook 20a. The rod 228 of cylinder 230 is
extended so that
the hook 20a is picked up in the outer end 236 and the barb 32a carried toward
and through the
tape 22a. As the hook 22a is advanced, the nose on the head 180 passes beneath
the blade 120a
and is received between the pins 254 before the barb 32a engages the tape 22a.
This prevents
tipping of the hook in the shoe 234 as the barb 32a is forced thmugh the tape
22a. After the barb
32a has pierced the tape 22a the head 180 of the hook 20a is carried by the
shoe 234 into
engagement with the strike face 246 of the anvil 244. Continued forward
movement of the shoe
234 causes the upper flank 240 to bear against the cross member 30a and move
the leg 28a in to
the groove 182 thereby locking the hook.. The upper flank 240 is positioned to
induce a hinging
of the leg 28a relative to the leg 26a and therefore rotate it in to the
groove 182. The convergent
flanks ensure that as the abutment is engaged, continued movement of the shoe
will allow limited
movement of the hook allowing the lower flank and cause continued pivotal
movement of the leg
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CA 02366091 2001-12-21
28a into the groove 128. Reversal of the actuators 230 releases the hook 20a
with the leg 28a
through the tape 22a and held in the locked position.
The shoe 234 is then fully retracted and the shuttle operated to transfer a
fiuther hook 22a
from the chute 106x. The blade 120a and the pins 254 are retracted, the motor
110a operated and
S the clamp 132a released to allow the tape to be advanced out of the slot
118a and unfolded along
the crossmember 30a. The process is repeated at each location at which a hook
is to be inserted
and the tape subsequently sewn to the curtain as described above.
Although the invention has been described with reference to certain specific
embodiments, various modifications thereof will be apparent to those skilled
in the art without
departing from the spirit and scope of the invention as outline in the claims
appended hereto.
For example different hooks may be used and the tape folded in a transverse
direction if
appropriate. Similarly, although the embodiments utilise a tape to receive the
hook, it will be
appreciated that the hook may be inserted in to any suitable web of flexible
material, including
the curtain itself, provide an appropriate feed mechanism is provided.
However, given the extent
of the curtain for horticultural applications it is believed that use of the
tape is preferred.
