Note: Descriptions are shown in the official language in which they were submitted.
Background of the Invention
The present invention relates to the field of knot tying using an automated
device to tie the
knot in a completely automatic fashion. There is a wide variety of knot tying
machines being
used in various fields, such as fishing hook to fishing line connections, in
surgery, in rebar tying,
and grape vine tying. While some of these machines are fully automatic, many
require some
human input. They also tie a limited number of knots, with a limited number of
string or wire
types. Some strings are harder to tie than others, as the string, if it does
not have tightly twisted
strands will not allow for back pressure on the string as it will tend to
unravel as back pressure
(compression loading) is applied. Additionally some strings are slippery and
therefore require
tighter gripping than others during the tying process. The biodegradable
string used in the
greenhouse industry is exactly the type of string that is both intolerant of
back pressure and is
very slippery. Examples of biodegradable string used in the greenhouse
industry include; BIO-
CORDENKATM, Elite Bio Twine', and PLA yarn (polylactic acid).
Summary of the Invention
It is the object of this invention to provide a method for tying a knot in a
string that attaches it
to an overhead wire, cable, or rod. The type of knot being tied is a slippery
half knot which
allows for easy release by pulling the end of the string. The string tying
device is fully automatic,
without the need for human intervention during operation. The primary use of
the knot tying
device is in the greenhouse industry where strings are used for the plants to
grow vertically,
there are thousands of such strings used in a greenhouse and currently they
are all tied
manually. These strings are made of a biodegradable material, so that when the
crop is
finished the strings and the vines can simply be composted together.
In operation: the following process is carried out:
1. The string tying unit is positioned around the wire or cable at the
location along the
wire or cable where the string will be tied
2. The U shaped guide is moved forward into position around the wire or cable
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Date Recue/Date Received 2023-10-14
3. The vacuum tube is moved up into position to collect the string after it
passes through
the U shaped guide
4. String is feed into the string tying unit by the belt feeder unit, where it
goes through the
U shaped guide and is collected by the vacuum tube ¨ adequate string is fed to
allow
for formation of the knot
5. The clamp (inner U) making up one side of the U shaped guide is closed
forming a path
for the string between the top of the U shaped guide and the vacuum tube which
is
raised, string is fed into the vacuum tube until there is enough to form a
knot and the
belt feeder stops. The vacuum tube is lowered and the string is pulled out to
form a
taught vertical stretch that can be accessed by the slotted jaw gripper.
6. The slotted jaw gripper is then advanced toward the string and then clamps
on the
string
7. The slotted jaw gripper is then pulled back, raised up to the centerline of
the U shaped
guide, and then advanced though the U shaped guide
8. The second gripper in line with the slotted jaw gripper is advanced into
the slotted jaw
gripper's jaws and clamps onto the string with the second gripper, taking the
string
through the U shaped guide and to the other side forming the shape of the
knot. When
the second gripper has the string the slotted gripper is released and the
slotted gripper
retracts
9. The inner U opens outward allowing the string to escape the U shaped guide
and go
around the wire or cable
10. As the second gripper grabs the string some string remains in the vacuum
tube and a
loop is formed which will be gripped by the second gripper.
11. The U shaped guide now retracts and the second gripper moves back, the
belt feeder
runs in reverse to tighten the knot, the tension between the loop in the
second Gripper
and the reverse pull of the feeder is applied to the drop end of the String
forming the
knot and causes the tension in the knot. The belt feeder then spools out the
length of
string required to reach the floor, and the string is cut.
12. The second gripper is then opened and retracted
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Date Recue/Date Received 2023-10-14
13. The string tying unit is then moved to the next location along the wire or
cable
In the typical greenhouse environment where tomatoes, peppers, and cucumbers
are grown on
strings, the strings are tied to a horizontal wire or cable that is suspended
between 8 and 15
feet above the floor of the greenhouse. In order to tie the stings to the wire
or cable, a
transport and lift mechanism is required that can navigate between the rows of
strings that are
being tied to the wire or cable. It is desirable that this transport and lift
mechanism travel along
the existing pipe system that is located between the rows and is currently
used during the
harvesting of the produce. It is also necessary the string tying device,
sitting on the lift and
transport system, be located at the level of the wire or string, with the
ability to adjust its
location to center vertically and horizontally on the wire or cable prior to
tying the knot. It is
also possible that there are two string tying devices mounted on the transport
and lift
mechanism so that two rows can have strings tied at the same time.
The travel and lift mechanism can be automatically controlled to move onto the
pipe system at
the start of a row, tie the first string, then move a pre-programmed distance
to tie the second
string, and so on to the end of the row, where it will reverse out of the row
and then move on
to the next row, until all rows have strings tied. It will naturally be
required that the travel and
lift mechanism be stopped from time to time to allow for reloading string,
batteries or fuel.
Brief Description of the Drawings
These and other objects of the invention will become apparent from reading a
detailed
description taken in conjunction with the drawings, in which:
FIG. 1 is a drawing showing the string tying machine located around the wire
or cable with the
U shaped guide extended and the vacuum tube in the up position.
FIG. 2 is a drawing showing the string tying machine after the string has been
feed into the
vacuum tube.
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Date Recue/Date Received 2023-10-14
FIG. 3 is a drawing showing the string tying machine after the vacuum tube and
the slotted jaw
gripper has been extended, to expose the string to the slotted jaw gripper.
FIG. 4 is a drawing showing the slotted jaw gripper clamped on the string.
FIG. 5 is a drawing showing the slotted jaw gripper clamped on the string, and
now in position
in the center of the U shaped guide.
FIG. 6 is a drawing showing the second gripper in position to clamp the string
between the jaws
of the slotted jaw gripper.
FIG. 7 is a drawing showing the second gripper clamping the string while the
slotted jaw gripper
is ready to release the string and retract.
FIG. 8 is a drawing showing the second gripper clamping the string retracting
while the U
shaped guide side opens and the string is released from the guide.
FIG. 9 is a drawing showing the transport and lift device on the greenhouse
rails, with the string
tying unit located in position around the wire or cable.
Detailed Description
With reference to FIG. 1 the string tying machine, 1, is shown positioned
around the wire or
cable, 2, that the string, 3, will be tied around. It consists of the
following key components: a
base plate, 4, two flat belts, 5, driven by pulleys, 6 and 7, and passing over
idler pulleys, 14, and
being tensioned by pulleys, 8, a roller guide assembly, 9, that allows
locating relative to the wire
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Date Recue/Date Received 2023-10-14
or cable, 2, a vacuum tube, 10, a slotted jaw gripper, 11, a U shaped guide,
13, that can open
completely on one side, and a second gripper, 15.
The spacing between the two flat belts, 5, is less than the diameter of the
string, 3, that passes
between them, so that there will be a gripping force generated on the string,
3. While flat belts,
5, are shown, it is also possible to use drive wheels to accomplish the string
feeding.
The U shaped guide, 13, is shown in the advanced position around the wire or
cable, 2, while
the vacuum tube, 10, is shown in its lifted position, ready to catch the
string, 3, after it passes
through the U shaped guide, 13. The slotted jaw gripper, 11, is shown in its
lower retracted
position, ready to advance to receive the string, 3, at a future time in the
operating cycle.
With reference to FIG. 2 the string tying machine, 20, is shown with the
moveable side, 21, of
the U shaped guide, 13, in the closed position to guide the string, 3, around
the wire or cable, 2.
With reference to FIG. 3 the string tying machine, 25, is shown with the
vacuum tube, 10,
rotated down out of the way after it has collected the string, 3, the slotted
jaw gripper, 11, is
now shown in an advanced position, ready to grip the string, 3, which is
hanging down between
the slotted jaw gripper, 11.
With reference to FIG. 4 the string tying machine, 30, is shown with the
slotted jaw gripper, 11,
now clamped on the string, 3.
With reference to FIG. 5 the string tying machine, 35, is shown with the
slotted jaw gripper, 11,
in its upper extended position, having been retracted, lifted, and extended,
while gripping the
string, 3.
With reference to FIG. 6 the string tying machine, 40, is shown with the
second gripper, 15,
extended such that its jaws are between the jaws of the slotted jaw gripper,
11.
Date Recue/Date Received 2023-10-14
With reference to FIG. 7 the string tying machine, 45, is shown with the
additional gripper, 15,
closed on the string, 3, and with the moveable side, 21, of the U shaped
guide, 13, opened so
that the string, 3, can fall out and touch the wire or cable, 2.
With reference to FIG.8 the string tying machine, 50, the second gripper, 15,
then retracts and
the belts, 5, driven by pulleys, 6 and 7, are reversed, tightening the knot
around the wire or
cable, 2. The jaws of the second gripper, 15, are then released and the
gripper is retracted.
With reference to FIG. 9 the complete apparatus for use in a greenhouse, 55,
consisting of the
string tying machine, 1, of FIG. 1, and the transport, 58, and lift mechanism,
57, is shown. An x-
y-z table, 56, is used to adjust the precise location of the string tying
machine, 1, to the location
of the wire or cable, 3. The relative location of the wire, 3, is determined
using cameras (not
shown) and the location information is used to place the string tying machine,
1, relative to the
wire or cable, 3. The transport system, 58, has wheels that run on the rails,
59, that are present
between the rows in the greenhouse. The transport system, 58, is fully or
partially autonomous
and computer controlled to allow tying of the vertical strings, 60, at proper
spacing along the
wire or cable, 3.
This invention has been described with reference to detailed descriptions of
preferred
embodiments. The details of the descriptions are given for the sake of
explanation only and are
not intended as limitations upon the scope and spirit of the appended claims.
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Date Recue/Date Received 2023-10-14
