WO2022066000A1

WO2022066000A1 - System and method for tying a knot

Info

Publication number: WO2022066000A1
Application number: PCT/MY2021/050078
Authority: WO
Inventors: Kok Long TAN; Jian Zhan CHEW; Soon Seng CHAI; Li Ren LEONG
Original assignee: Emec Packaging Solutions Sdn Bhd
Priority date: 2020-09-24
Filing date: 2021-09-23
Publication date: 2022-03-31

Abstract

This invention relates to a system (1000) and method for tying a knot around an article (1150). The system comprises a knot-tying mechanism that uses a filament (1140) to form the knot in a knot-tying process, the knot-tying mechanism includes a filament delivery device (100) that leads movement of the filament (1140) around the article (1150) to form a coil (1141) having at least one loop; a hooking device (200) configured to create a bight (1142) of the knot that passes through the coil (1141); and a filament tensioning device (300) for tightening the knot upon creation of the bight (1142); wherein the hooking device (200) has a hook (230) rotatable about its pivot point to hook and unhook the filament (1140) for forming the bight (1142).

Description

SYSTEM AND METHOD FOR TYING A KNOT

FIELD OF INVENTION

This invention relates to a knot-tying system and method, in particular, the system and the method are used for closing an opening of an article by the knot.

BACKGROUND OF THE INVENTION

Generally, the term ‘knot’ includes loop knots, hitches, splices and anchors. These knots come in various structures and serve different functions, whether it is for practical or decorative use. Knots intended for practical use are commonly utilized for binding, attaching and constricting objects, whereas knots for decorative use exhibit repetitive patterns and usually possess complex structures to provide an attractive appeal.

Often, knots are formed manually by hand. However, manual tying of knots is timeconsuming, especially when a large number of knots are required, errors are prone to happen and the operation is tedious. Automated knot-tying machines are thus employed as an alternative to manual tying. An example of such machine is described in US8622440B2 wherein the machine is a system that comprises a knot-tying device for tying a filament in a knot around an article and a filament delivery device from which the filament is drawn. The filament delivery device is in the form of a cartridge having a housing sized and arranged to be releasably attached to the knot-tying device where the housing has an opening through which pre-cut or loosely coupled lengths of the filament can be drawn. The knot-tying device comes with a shuttle attachable to the filament where the shuttle is configured to move during a knot-tying process around an article to be tied. In addition, the knot-tying device also includes a device for pulling the filament away from the article at appropriate times during the knottying process. However, operation of this machine is restricted within a pair of ring assemblies that surrounds the articles to be tied. The shuttle assembly moves between and within channels that are formed in the ring assemblies while the hook of the looping hook assembly is driven into and out of the area between the ring assemblies to hook and release the filament for creating space in which the shuttle assembly, while carrying the filament, passes by to create the desired knot. Other than movement restrictions of the machine components, the knot-tying process is also complicated with such component arrangement and monitoring of the components performing the process is difficult as viewing of the components is blocked by the ring assemblies. Further, this machine is catered for tying a bundle of articles and not for closing an opening of a bag that contains articles therein.

To close the opening of a bag containing articles, especially an ice bag, the twist tie machine is commonly used. Prior to the tying process, the opening part of the bag is constricted to form a bag neck that is fed to the machine to be encircled by a wire that is twisted to hold the bag neck in a desired dimension to entirely close the opening or restrict size of the opening. Another way to close the opening of a bag is to use a sealing machine that utilizes a tape with adhesive to wrap around the bag neck. The opening of the bag is constricted to form the bag neck that is slid through a slot of the sealing machine in a downward direction. The tape wraps around the bag neck instantly and the tape is cut automatically. Both machines require constricting of the bag neck, usually through twisting, prior to applying a tying component to secure the constricted opening in a desired dimension. This step is usually performed manually by hand which is time consuming. Further, the sharp edges of the wire can cause injuries or damages of objects including the bag or articles near the bag. Besides that, to open the bag sealed with the tape, cutting of the tape is usually required and therefore, the tape is not reusable. Solutions to the abovementioned limitations and drawbacks of current technologies for tying an article are hereby disclosed.

SUMMARY OF INVENTION

The main object of the present invention is to provide an automated knot-tying system and method for forming a knot around an article. The article can be a bundle or a stack of objects, but preferred to be a bag with an opening such that the knot closes the opening of the bag. A further object of the present invention is to provide a knottying system and method that are capable of forming a quick-release knot around the article to offer convenience to users to untie the knot. Another object of the present invention is to provide a knot-tying system with a knot-tying mechanism that is catered to form a particular knot without the involvement of excessive machinery components or complicated arrangement of components. The present invention introduces a hooking device with a hook configured to form the bight of the knot. The bight can be formed by using just one hook of the hooking device. In addition, the present invention does not restrict movement of the knot-tying mechanism components within a closed boundary. Without a closed boundary, the present invention enables monitoring of the knot-tying mechanism during operation of the system and eases troubleshooting of the components when failure of machine operation occurs. Additionally, reusable tying component to form the knot is promoted in the present invention. This automated system also serves to operate efficiently by being able to complete the knot-tying process of a high volume of articles within a short period.

At least one of the preceding objects is met, in whole or in part, by the present invention, in which one aspect of the present invention provides a system for tying a knot around an article which comprises a knot-tying mechanism that uses a filament to form the knot in a knot-tying process. The knot-tying mechanism includes a filament delivery device that leads movement of the filament around the article to form a coil having at least one loop; a hooking device configured to create a bight of the knot that passes through the coil; and a filament tensioning device for tightening the knot upon creation of the bight; wherein the hooking device has a hook rotatable about its pivot point to hook and unhook the filament for forming the bight.

In one of the embodiments of the invention, the hook, in a coil latching state, has a first groove on a surface facing away from the article for hooking the filament of the coil when the coil is wound therearound, and a second groove on a surface facing the article.

On the other hand, it is preferred that the hook, in a bight latching state, has the first groove rotated towards the article to release the filament of the coil, and the second groove rotated to face away from the article while hooking a standing part of the coil to form the bight.

According to a preferred embodiment of the invention, the filament tensioning device is movable to pull the standing end of the filament for tightening the knot.

Preferably, the hooking device includes a force exerting member to rotate the hook.

It is preferred that the filament delivery device holds a working end of the filament to move around the article while increasing the length of the filament used to form the knot.

The filament tensioning device is preferred to have a retainer to hold a standing end of the filament.

Based on a preferred embodiment, the system further comprises a cutter for separating the used filament used to form the knot from the unused filament attached to the system.

The cutter is preferred to be incorporated at the filament tensioning device that is movable to cut the filament attached to either or both of the filament delivery device and filament tensioning device.

In a preferred embodiment, the system further comprises a filament holder that holds the filament and supplies the filament to the filament delivery device and then to the filament tensioning device, whereby length between the filament tensioning device and filament delivery device increases as the filament delivery device, while carrying the filament, moves around the article during the knot-tying process.

Preferably, the article is a bag having an opening to be closed by the knot.

It is preferred that the system further comprises a gripper for gripping the opening of the article during the knot-tying process.

Based on a preferred embodiment, the system further comprises an article holder for retaining the article in position during the knot-tying process.

In another aspect of the present invention, a method for tying a knot around an article using a system according to the system described above is provided. The method comprises the step of performing a knot-tying process by a knot-tying mechanism through forming a coil having at least one loop around the article by a filament delivery device; creating a bight of the knot that passes through the coil by a hooking device; and tightening the knot by a filament tensioning device upon creation of the bight; wherein the bight is created by hooking and unhooking the filament by a hook of the hooking device that is rotatable about its pivot point.

According to a preferred embodiment, the coil is formed by winding a working end of the filament, in a first curve direction, around the article and the hook.

It is preferred that the method further comprises the step of creating a reverse turn, upon forming the coil, by passing the working end of the filament under or across a standing part of the filament being a first loop of the coil in a second curve direction that opposes the first curve direction.

Based on a preferred embodiment, the bight is formed by rotating the hook from a coil latching state, where the filament of the coil is hooked around a first groove of the hook that faces away from the article when the coil is formed and a second groove of the hook is configured to face the article, to a bight latching state where the first groove is rotated towards the article to release the filament of the coil, and the second groove is rotated to face away from the article while hooking a portion of the reverse turn lying under or across the first loop of the coil to pass it through the coil for forming the bight.

It is preferred that the knot is tightened by moving the filament tightening device to pull a standing end of the filament that is held by the filament tightening device.

Preferably, the used filament to form the knot is separated from the unused filament attached to the system by a cutter incorporated at the filament tensioning device that is movable to cut the filament attached to either or both of the filament delivery device and filament tensioning device.

The filament is preferred to be supplied from a filament holder that supplies the filament to the filament delivery device and the to the filament tensioning device, whereby length between the filament tensioning device and filament delivery device increases as the filament delivery device, while carrying the filament, moves around the article during the knot-tying process. In a preferred embodiment, the article is gripped by a gripper during the knot-tying process.

It is preferred that the article is retained in position by an article holder during the knot-tying process.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention will now be described in greater detail with reference to the accompanying drawings.

Figure 1 is a side view of the knot-tying system.

Figure 2 is an exploded perspective view of the knot-tying system.

Figure 3 is a perspective view of the article holder for holding the article during the knot-tying process.

Figure 4 is a perspective view of the operation assembly that comprises the actuator, motor, knot-tying mechanism and gripper.

Figure 5 is a side view of the operation assembly that comprises the actuator, motor, knot-tying mechanism and gripper.

Figure 6 is a back view of the operation assembly that comprises the actuator, motor, timing gear, knot-tying mechanism and gripper.

Figure 7 is a perspective view of the gripper for gripping the article.

Figure 8 is a perspective view of a portion of the knot-tying mechanism that includes the timing gear, filament delivery device, hooking device and filament holder.

Figure 9 is a perspective view of the filament holder.

Figure 10 is a side view of the hooking device.

Figure 11 is a perspective view of the hooking device.

Figure 12 is a perspective view of the motor.

Figure 13 is a perspective view of the filament tensioning device.

Figure 14 is a side view of the filament tensioning device.

Figure 15 is a perspective view of the knot-tying mechanism performing step 1 of the knot-tying process where a standing end of the filament is held by the filament tensioning device, and a working end of the filament is held by the filament delivery device to form at least one loop of the coil around the article and first groove of the hook.

Figure 16 is a perspective view of the knot-tying mechanism performing step 2 of the knot-tying process where the filament delivery device has formed at least one loop of the coil around the article and the hook and is ready to form the reverse turn.

Figure 17 is a perspective view of the knot-tying mechanism performing step 3 of the knot-tying process where the hook is rotated to form the bight of the knot.

Figure 18 is a perspective view of the knot-tying mechanism performing step 4 of the knot-tying process where the filament tightening device pulls the standing end of the filament to tighten the knot. Figure 19 is a top view of the knot-tying mechanism performing step 4 of the knottying process where the filament tightening device pulls the standing end of the filament to tighten the knot.

Figure 20 is a perspective view of the knot-tying mechanism performing step 5 of the knot-tying process where the standing end of the filament is released by the filament tensioning device.

Figure 21 is a perspective view of the knot-tying mechanism performing step 6 of the knot-tying process where the used filament to form the knot is separated from the unused filament attached to the system by a cutter incorporated at the filament tensioning device that is movable to cut the filament attached to the filament delivery device.

Figure 22 is a perspective view of the hooking device and article when step 1 of the knot-tying process is carried out where the hook is in a coil latching state that the filament is delivered around the article and first groove of the hook to form the first loop of the coil in the first curve direction.

Figure 23 is a perspective view of the hooking device and article when step 2 of the knot-tying process is carried out where the first loop of the coil is formed.

Figure 24 is a perspective view of the hooking device and article when step 2 of the knot-tying process is carried out where the second loop of the coil is formed.

Figure 25 is a side view of the hooking device and article when step 3 of the knottying process begins by exerting a downward force to the hook by the force exerting member to rotate the hook.

Figure 26 is a perspective view of the hooking device and article when step 3 of the knot-tying process is carried out where the reverse turn is created by passing the working end of the filament under or across a standing part of the filament being a first loop of the coil in a second curve direction that opposes the first curve direction.

Figure 27 is a perspective view of the hooking device and article when step 3 of the knot-tying process is carried out where the hook is in a bight latching state that the first groove is rotated towards the article to release the filament of the coil, and the second groove is rotated to face away from the article while hooking the portion of the reverse turn lying under or across the first loop of the coil to pass it through the coil for forming the bight.

Figure 28 is a perspective view of the hooking device and article when step 4 of the knot-tying process is carried out where the knot is tightened around the article by the filament tensioning device that pulls the standing end of the filament.

DETAILED DESCRIPTION OF THE INVENTION

For a better understanding of the invention, preferred embodiments of the invention that are illustrated in the accompanying drawings will be described in detail.

Disclosed herein is a system (1000) and method for tying a knot around an article (1150). Although the article (1150) is preferably a bag with an opening that is to be constricted or closed by the present invention through having the knot encircling and sealing the opening at the bag neck (1151), the present invention is also applicable for bonding more than one items that define the article (1150) such as a stack of items, a bundle of items and any collection of items. Whilst there is no limitation to the type of knot formed by the knot-tying system (1000) disclosed herein, a quick-release knot is most preferred and is used as an exemplary knot herein and illustrated in the drawings to explain the operation of the present invention. In a preferred embodiment of the knot-tying system (1000) shown in Figure 1 and Figure 2, the components of the system (1000) are housed within a support frame (1100) that comes with a container (1110) having a top plate (1111), side walls and an open base at the top section of the frame (1100) in which an operation assembly (1300) of the system (1000) is accommodated therewithin which includes an actuator (500), a motor (600), a knot-tying mechanism and a gripper (400) is accommodated therewithin. The article (1150) to be tied is fed through the front door or opening of the frame (1000), preferably through a conveyer or manually by hand, to an operation zone where the article (1150) is subjected to the knot-tying process, and is retained in a position that is reachable by the knot-tying mechanism to perform the knot-tying process by an article holder (700). The article holder (700) is provided below the operation assembly (1300). Upon completion of the knot-tying process the article holder (700) releases the article (1150) such that it can be directed or carried out of the operation zone by the conveyer or manually by hand. It should however be noted that the positioning of the operation assembly (1300) and article holder (700) is not limited to a top-bottom relationship, and they can be positioned side by side or in any desired position as long as the operation of the system (1000) can be carried out. Further, the incorporation of the frame (1100), especially with the container (1110), is optional. A controlling device (1200) is provided at the frame (1100) to allow users to manipulate operation of the knot-tying system (1000)

Figure 3 illustrates an exemplary article holder (700) used in the present invention. The article holder (700) has a platform (720) with one or more clamping units (710) that serve to clamp the article (1150) in position during the knot-tying process. Each clamping unit (710) has two clamping portions (711), preferably in curved shape to form a cylindrical clamping unit (710) when they are in a closed state. The area surrounded by the clamping unit (710) is the loading site of the article (1150). There are two extendable legs (730) mounted to the platform (720) and each clamping unit (710) for adjusting the distance between the two clamping portions (711). Prior to feeding the article (1150) to be clamped, the clamping units (710) are in an open state where they are separated by the extended legs (730). Once an article (1150) is disposed on the loading site, the legs (730) retract to move the clamping portions (711) toward each other to form the cylindrical clamping unit (710) to clamp the article (1150). When the clamping unit (710) is in closed state, the knot-tying process is carried out. In an article holder (700) that has more than one clamping units (710), the article holder (700) can be configured to interchangeably use more than one of the clamping units (710) to clamp a single article (1150). For instance, in an article holder (700) with two clamping units (710), the first clamping unit (710a) is positioned in a loading zone and a second clamping unit (710b) is positioned in an operation zone. When the article (1150) is clamped by the first clamping unit (710a) in the loading zone, the article (1150) is sent to the operation zone by moving the first clamping unit (710a) to the operation zone, while the second clamping unit (710b) moves to the unloading zone. Once the article (1150) reaches the operation zone, the first clamping unit (710a) unclamps the article (1150) and moves back to the loading zone while the second clamping unit (710b) returns to the operation zone to clamp the article (1150) when the knot-tying process is being performed. During this time, a second article (1150) to be tied can be disposed at the loading zone to be clamped by the first clamping unit (710a). When the knot-tying process is completed, the second clamping unit (710b) moves the article (1150) to the unloading zone and unclamps the article (1150) to be unloaded, while the first clamping unit (710a) delivers the second article (1150) to be tied to the operation zone.

Figure 4 to Figure 6 depict the operation assembly (1300) that comprises the actuator (500), motor (600), knot-tying mechanism and gripper (400). The actuator (600), preferably a pneumatic actuator, is applied for controlling operation of the gripper (400) and some devices of the knot-tying mechanism. The knot-tying mechanism includes a filament delivery device (100), a hooking device (200) and a filament tensioning device (300). Both the filament delivery device (100) and hooking device (200) are regulated by the actuator (600), whereas the filament tensioning device (300) is controlled by the motor (600). A timing gear (800) is incorporated to function with the actuator (500) to synchronize rotation of the filament delivery device (100). The timing for rotating the filament delivery device (100) by the timing gear (800) is programmed. The center section of the operation zone is occupied by the actuator (500), timing gear (800), gripper (400) and hooking device (200). The gripper (400) and hooking device (200) are suspended from the center of the timing gear (800) with the hooking device (200) being mounted at a position outside of the gripping zone to avoid interfering operation of the gripper (400). Suspended from a side of the timing gear (800) is the filament delivery device (100) that is rotatable around the article (1150) gripped by the gripper (400). One side section of the operation zone is occupied by the motor (600) and filament tensioning device (300).

With reference to Figure 7, the gripper (400) has a set of claws (410) that is configured to grip and free the article (1150). In the embodiment shown in Figure 7, the claws (410) are rotatable to a position away from the article (1150) to free the article (1150) from being gripped, and rotatable to a position close to the article (1150) to grip it. Alternatively, the claws (410) can be extendable or retractable to move towards or away from the article (1150). Other than the article holder (700), the gripper (400) also functions to hold the article (1150) in position within the operation zone. When the gripper (400) is positioned at the top of the article (1150), the gripped article (1150) is suspended from the gripper (400). Such gripper (400) is suitable for use to hold the article (1150) that is in the form of a bag, in particular, the gripper (400) grips the opening part of the bag and constricts the opening, forming a bag neck (1151) for the knot to be tied therearound. The part of the article (1150) that is not gripped is held by the article holder (700). In the example of the bag as the article (1150), the body of the bag that is not to be tied is held by the article holder (700). With the use of the article holder (700) with two clamping units (710), when the first clamping unit (710a) is moved to the operation zone and releases the article (1150), the gripper (400) is utilized to grip the article (1150) when it is not clamped by any clamping unit (710) of the article holder (700). The first clamping unit (710a) leaves the operation zone to the loading zone while the second clamping unit (710b) arrives at the operation zone to clamp the article (1150) while the knot-tying process progresses.

A portion of the knot-tying mechanism is illustrated in Figure 8, where the timing gear (800), filament delivery device (100), hooking device (200) and filament holder (900) are shown. The filament delivery device (100) is in the form of an arm that extends downwardly from the timing gear (800). The free end of the filament delivery device (100) has a guiding member (110) with an outlet for the filament (1140) to come out of the filament delivery device (100). The guiding member (110) is preferred to be perpendicularly projected from the arm to face the article (1150). Serving as a filament supplier, the filament holder (900) is disposed on the timing gear (800) to supply the filament (1140) to the filament delivery device (100) and then to the filament tensioning device (300). The filament (1140) is the tying component that forms the knot. It can be any flexible elongate element that is preferably made of reusable material such as a string, rope, strap and wire. The filament holder (900), shown in Figure 9, is in the form of a cylinder (910) for the filament (1140) to be wrapped therearound.

Figure 10 and 11 depict the hooking device (200) that comes in two portions according to a preferred embodiment, the force exerting portion (220) and the hooking portion (210). The hooking portion (210) has an elongate member with one fixed end mounted to the timing gear (800) and a free end pivotally connected with a hook (230) that is rotatable around its pivot point at the elongate member. The hook (230) can be seen clearly in Figure 22 to 28 where the part mounted to the pivot point is in the form of a gear (233) to control rotation position and timing of the hook (230). The hook (230) is extended from the gear (233) and has two grooves, each at one opposing side of the hook (230). In a coil latching state, the first groove (231) of the hook is on a surface facing away from the article (1150) and the second groove (232) is on a surface of the hook (230) that faces the article (1150). On the other hand, in a bight latching state, the first groove (231) is rotated towards the article (1150) whereas the second groove (232) is rotated to face away from the article (1150). The force exerting portion (220) which is pivotally connected to the hooking portion (210) has a force exerting member (221) at its end. The force exerting portion (230) is rotatable around a pivot point that mounts the force exerting portion (220) to the hooking portion (230). Rotation of the force exerting portion (220) allows the force exerting member (221) to be in contact with the hook (230) in order to exert a force to the hook (230) to rotate the hook (230). When the hook (230) is rotated to a desired position, the force exerting member (221) becomes contactless with the hook (230) to stop further rotation of the hook (230). In an example of the system (1000) where the article (1150) is in a standing position for the knot to be tied around the article (150) where the coil (1141) lies in a transverse plane, the hook (230) is preferred to rotate vertically about a horizontal axis of the pivot point of the hook (230).

The motor (600) that controls operation of the filament tensioning device (300) shown in Figure 12 is preferably a worm gear and servo motor that is linked to the filament tensioning device (300) positioned below it. The filament tensioning device (300) has a plate (310) projecting in a direction towards the article (1150) to be tied. The plate (310) is formed with a retainer (320) to hold a standing end of the filament (1140). The retainer (320) can come in more than one retaining units, each with a rotatable door that can be closed to keep the standing end of the filament (1140) attached to the filament tensioning device (300), and open to release the standing end of the filament (1140). With the motor (600) driving movement of the filament tensioning device (300), the filament tensioning device (300) is movable away from the article (1150) to pull the standing end of the filament (1140) to attain a tightened knot.

In the present invention, a cutter (330) is provided to separate the used filament (1140a) employed to form the knot from the unused filament (1140b) attached to the system (1000) upon formation of the knot. The cutter (330) can be provided in any position within the system (1000) that can reach appropriate positions of the filament (1140) to cut it. In the preferred embodiment of the present invention, the cutter (330) is incorporated at the filament tensioning device (300), preferably at the end of the plate (310) and adjacent to the retainer (320). The cutter (330) can have two blades, with one of them pivotally connected to the end of the plate (310) and the other remaining static. When the cutter (330) is in an open state, the movable blade is moved upwardly away from the static blade. To cut the filament (1140) in between the blades, the movable blade is moved downwardly towards the static blade to cut the filament (1140). With the filament tensioning device (300) being movable, the cutter (330) can cut the filament (1140) attached to either or both of the filament delivery device (100) and filament tensioning device (300). In addition, the cutter (330) can also be used to cut any portions of the filament (1140) that are not attached to the filament delivery device (100) and filament tensioning device (300). In the preferred embodiment, the retainer (320) releases the standing end of the filament (1140) without having to cut the standing end of the filament (1140), and the filament tensioning device (300) is moved towards the filament delivery device (100) to cut the working end of the used filament (1140a) such that it is separated from the unused filament (1140b) that is still attached to the system (1000). Upon cutting the working end of the filament (1140a), an unused portion of the filament (1140b) is supplied to the filament tensioning device (300) through the outlet of the filament delivery device (100) that is to be used as the standing end of the filament (1140) which is retained in position by the retainer (320) on the plate (310) of the filament tensioning device (300) and the filament tensioning device (300) moves away from the filament delivery device (100) to be ready for the next knot-tying process.

Figure 15 to Figure 11 illustrate the knot-tying process with the use of the knot-tying system (1000) disclosed herein. Figure 22 to Figure 28, on the other hand, focuses on the configuration of the hook (230) with respect to the article (1500) during the knottying process. A bag is used an example of the article (1500) in the drawings. In particular, the knot is to be formed around the bag neck (1141). The arrows in the drawings indicate movement direction of the components. The process starts with the filament (1140) from the filament holder (900) being supplied to the filament delivery device (100) and then to the filament tensioning device (300). The portion of the filament (1140) retained at the filament tensioning device is the standing end of the filament (1140) to form the knot whereas the portion of the filament (1140) outside the guiding member (110) of the filament delivery device (100) and adjacent to the outlet of the guiding member (110) is the working end of the filament (140). The length between the filament tensioning device (300) and filament delivery device (100) increases as the filament delivery device (100), while carrying the filament (1140), moves around the article (1150) during the knot-tying process. As the filament delivery device (100) delivers the filament (1140), the filament holder (900) supplies longer filament (1140) between the filament delivery device (100) and filament tensioning device (300). Figure 15 is a perspective view of the knot-tying mechanism performing step 1 of the knot-tying process where a standing end of the filament (1140) is held by the filament tensioning device (300), and a working end of the filament (1140) is held by the filament delivery device (100). The filament delivery system (1000) is ready to form at least one loop of the coil (1141) around the article (1150) and the first groove (231) of the hook (230). Figure 22 is a perspective view of the hooking device (200) and article (1150) when step 1 of the knot-tying process is carried out where the hook (230) is in a coil latching state such that the filament (1140) of the coil (1141) can be hooked around the first groove (231) of the hook.(230) to form the first loop of the coil (1141) in the first curve direction which can be a clockwise or anti-clockwise direction. In the coil latching state, the first groove (231) of the hook (230) is on a surface of the hook (230) that faces away from the article (1150), and the second groove (232) is on a surface facing the article (1150).

The completion of one turn around the article (1150) and first groove (231) of the hook (230) forms one loop of the coil (1141). Preferably, the loop formed is an overhand loop. Figure 23 illustrates the formation of the first loop, whereas Figure 24 depicts the formation of the second loop of the coil (1141). There is no limitation to the number of loops of the coil (1141). Step 2 of the knot-tying process is shown in Figure 16 where the filament delivery device (100) has completed the formation of the coil (1141) with at least one loop around the article (1150) and the hook (230) by winding the working end of the filament (1140) therearound. The system (1000) is then ready to form a reverse turn of the knot.

Figure 25 is a side view of the hooking device (200) and article (1150) when step 3 of the knot-tying process begins by exerting a downward force to the hook (230) by the force exerting member (221) to rotate the hook (230) upon formation of the coil (1141). While the hook (230) begins to rotate to transform from the coil latching state to a bight latching state, a reverse turn of the filament (1140) is created, as shown in Figure 26, by passing the working end of the filament (1140) from the last created loop to the opposite end of the coil (1141) which is under or across a standing part of the filament (1140) that is the first loop of the coil (1141) in a second curve direction that opposes the first curve direction. If the first curve direction is an anti-clockwise direction, the second curve direction is a clockwise direction.

Figure 17 is a perspective view of the knot-tying mechanism performing step 3 of the knot-tying process where the hook (230) is rotated to form a bight (1142) of the knot. The hook (230) rotates vertically about the horizontal axis of its pivot point. In the bight latching state of the hook (230), the first groove (231) is rotated towards the article (1150) to release the filament (1140) of the coil (1141), and the second groove (232) is rotated to face away from the article (1150) while hooking a standing part of the coil (1141) which is a portion of the filament (1140) of the reverse turn lying across or under the first loop to form the bight (1142). Figure 27 shows the hook (230) passing the bight (1142) through the coil (1141) from the first loop to the last loop and extends out of the last loop. The bight (1142) is a turn that is at least substantially perpendicular to the coil (1141).

After the bight (1142) is formed, the filament tightening device (300) moves further away from the article (1150) in step 4 of the knot-tying process, thereby pulling the standing end of the filament (1140) that is held by the retainer (320) at the filament tensioning device (300) to tighten the knot where the loops of the coil (1141) encircling the bight (1142) and the article (1150) constrict. Figure 18 and Figure 19 show the knot-tightening process. The diameter of the coil (141) is decreased as shown in Figure 28, indicating that the knot-tightening process is conducted.

After the tightening step, the knot is formed. The knot described herein is a quick release knot whereby it can be released by pulling the bight (1142). The hook (230) is then rotated to release the bight (1142) whereby the second groove (232) is rotated to a position that unhooks the bight (1142). To separate the filament (1140a) used for forming the knot from the unused filament (1140b) that is still attached to the knottying system (1000), the cutter (330) is used to cut the filament (1140). In the preferred embodiment of the invention, the retainer (320) of the filament tensioning device (300) releases the standing end of the filament (1140) in step 5 of the knottying process as shown in Figure 20.

To separate the used filament (1140a) from the unused filament (1140b) at the filament delivery device (100), the filament tensioning device (300) moves to the filament delivery device (100) and cuts the working end of the filament (1140) in step 6 of the knot-tying process as shown in Figure 21. It is preferred that the plate (310) of the filament tensioning device (300) lies beneath the filament delivery device (100) and the cutter (330) is in an open state where the movable blade is moved upwards and away from the static blade to allow the filament (1140) to be positioned in between the blades of the cutter (330). A downward movement of the movable blade cuts the filament (1140). With the plate (310) of the filament tensioning device (300) being underneath the filament delivery device (100), the filament (1140) can be delivered to the filament tensioning device (300) to be retained therewithin as the standing end of the filament (1140) for the next knot-tying process. The next knottying process begins when the filament tensioning device (300) moves away from the filament delivery device (100) and the filament delivery device (100) starts to rotate around the article (1150). The tied article is then ready to be unloaded from the system (1000). Although the description above contains many specifications, it is understood that the embodiments of the preferred form are not to be regarded as a departure from the invention and it may be modified within the scope of the appended claims.

Claims

1. A system (1000) for tying a knot around an article (1150) comprising a knot-tying mechanism that uses a filament (1140) to form the knot in a knottying process, the knot-tying mechanism includes a filament delivery device (100) that leads movement of the filament (1140) around the article (1150) to form a coil (1141) having at least one loop; a hooking device (200) configured to create a bight (1142) of the knot that passes through the coil (1141); and a filament tensioning device (300) for tightening the knot upon creation of the bight (1142); wherein the hooking device (200) has a hook (230) rotatable about its pivot point to hook and unhook the filament (1140) for forming the bight (1142).

2. The system (1000) according to claim 1, wherein the hook (230), in a coil latching state, has a first groove (231) on a surface facing away from the article (150) for hooking the filament (1140) of the coil (1141) when the coil (1141) is wound therearound, and a second groove (232) on a surface facing the article (1150).

3. The system (1000) according to claim 2, wherein the hook (230), in a bight latching state, has the first groove (231) rotated towards the article (1150) to release the filament (1140) of the coil (1143), and the second groove (232) rotated to face away from the article (1150) while hooking a standing part of the coil (1141) to form the bight (1142).

4. The system (1000) according to any one of the preceding claims, wherein the hooking device (200) includes a force exerting member (221) to rotate the hook (230). The system (1000) according to any one of the preceding claims, wherein the filament delivery device (100) holds a working end of the filament (1140) to move around the article (1150) while increasing the length of the filament (1140) used to form the knot. The system (1000) according to any one of the preceding claims, wherein the filament tensioning device (300) has a retainer (320) to hold a standing end of the filament (1140). The system (1000) according to claim 6, wherein the filament tensioning device (300) is movable to pull the standing end of the filament (1140) for tightening the knot. The system (1000) according to any one of the preceding claims, further comprising a cutter (330) for separating the used filament (1140a) applied to form the knot from the unused filament (1140b) attached to the system (1000). The system (1000) according to claim 8, wherein the cutter (330) is incorporated at the filament tensioning device (300) that is movable to cut the filament (1140) attached to either or both of the filament delivery device (100) and filament tensioning device (300). The system (1000) according to any one of the preceding claims, further comprising a filament holder (900) that holds the filament (1140) and supplies the filament (1140) to the filament delivery device (100) and then to the filament tensioning device (300), whereby length between the filament tensioning device (300) and filament delivery device (100) increases as the filament delivery device (100), while carrying the filament (1140), moves around the article (1150) during the knot-tying process.

11. The system (1000) according to any one of the preceding claims, wherein the article (1150) is a bag having an opening to be closed by the knot.

12. The system (1000) according to claim 11, further comprising a gripper (400) for gripping the opening of the article (1150) during the knot-tying process.

13. The system (1000) according to any one of the preceding claims, further comprising an article holder (700) for retaining the article (1150) in position during the knot-tying process.

14. A method for tying a knot around an article (1150) using a system (1000) according to any one of the preceding claims, the method comprising the step of performing a knot-tying process by a knot-tying mechanism through forming a coil (1141) having at least one loop around the article (1150) by a filament delivery device (100); creating a bight (1142) of the knot that passes through the coil (1141) by a hooking device (200); and tightening the knot by a filament tensioning device (300) upon creation of the bight (1142); wherein the bight (1142) is created by hooking and unhooking the filament (1140) by a hook (230) of the hooking device (200) that is rotatable about its pivot point.

15. The method according to claim 14, wherein the coil (1141) is formed by winding a working end of the filament (1140), in a first curve direction, around the article (1150) and the hook (230). The method according to claim 15, further comprising the step of creating a reverse turn, upon forming the coil (1141), by passing the working end of the filament (1140) under or across a standing part of the filament (1140) being a first loop of the coil (1141) in a second curve direction that opposes the first curve direction. The method according to claim 16 wherein the bight (1142) is formed by rotating the hook (230) from a coil latching state, where the filament (1140) of the coil (1141) is hooked around a first groove (231) of the hook (230) that faces away from the article (1150) when the coil (1141) is formed and a second groove (232) of the hook (230) is configured to face the article (1150), to a bight latching state where the first groove (231) is rotated towards the article (1150) to release the filament (1140) of the coil (1141), and the second groove (232) is rotated to face away from the article (1150) while hooking a portion of the reverse turn lying under and across the first loop of the coil (1141) to pass it through the coil (1141) for forming the bight (1142). The method according to any one of claims 14 to 17, wherein the knot is tightened by moving the filament tightening device (300) to pull a standing end of the filament (1140) that is held by the filament tightening device (300). The method according to any one of claims 14 to 18, wherein the used filament (1140a) to form the knot is separated from the unused filament (1140b) attached to the system (1000) by a cutter (330) incorporated at the filament tensioning device (300) that is movable to cut the filament attached to either or both of the filament delivery device (100) and filament tensioning device (300). The method according to any one of claims 14 to 19, wherein the filament (1140) is supplied from a filament holder (900) that supplies the filament (1140) to the filament delivery device (100) and the to the filament tensioning device (300), whereby length between the filament tensioning device (300) and filament delivery device (100) increases as the filament delivery device

(100), while carrying the filament (1140), moves around the article (1150) during the knot-tying process. The method according to any one of claims 14 to 20, wherein the article (1150) is gripped by a gripper (400) during the knot-tying process. The method according to any one of claims 14 to 21, wherein the article (1150) is retained in position by an article holder (700) during the knot-tying process.