Method for closing a knitted tubular article at its axial ends

Abstract

A method for closing a knitted tubular article at its axial ends at the end of its production cycle on a circular hosiery knitting machine comprises: - producing the article until the final knitting cycle is performed, holding the knitted loops of the final knitting cycle in the heads of the machine's needles forming them; - individually gripping the loops by a pick-up device provided with a pick-up element, the pick-up element being arranged to abut against a region of the shank of each needle located close to a latch opposite the head; - removing the article, holding each loop of the final knitting cycle formed by means of the pick-up element; - positioning the article at a sewing station; - individually transferring the loops from the pick-up element to a spike of an annular device consisting of two half-annular parts; - inverting the article by means of the handling device; - superimposing each loop of one half of the final knitting cycle on the corresponding loop of the other half by turning over on the same spike of the handling device; - sewing the pairs of knitted loops superimposed on each other; - releasing the article from the handling device, the article removal step comprising a first extraction preparation step, a second article extraction step and a third article transfer step. A specific order of commands for the different steps is provided.

Description

Technical Field

[0001] The present invention relates to a method for closing a knitted tubular article at its axial ends at the end of its production cycle on a circular hosiery knitting machine or similar equipment. Background Art

[0002] It is known to produce knitted tubular articles such as hosiery, usually with the aid of circular hosiery knitting machines, and which are opened at both axial ends when unloaded from the machine.

[0003] In the case of hosiery articles, after being unloaded from the machine in which they are manufactured, the toe needs to be closed, an operation performed with the aid of a sewing or binding machine.

[0004] Since this operation requires the use of additional machines and labor, which significantly affects the overall production costs of hosiery articles, various technologies have been proposed to automate the closing of the toe of hosiery articles, or more generally, to automate the closing of the axial ends of tubular knitted articles produced by circular hosiery knitting machines or similar equipment.

[0005] The various technologies proposed so far can be divided into two main categories: the first category includes technologies based on performing the closing at the beginning or end of the production of the products directly on the machine used to produce these products, and the second category includes technologies based on performing the closing in a sewing station or connecting station provided for this purpose, which is separated from the machine used to produce the products.

[0006] The first category has the disadvantage that the productivity of the machine is significantly limited, since the closing operation requires a certain amount of time during which the machine cannot produce new products.

[0007] The second category, to which the technology described in patent IT 1,300,622 belongs, makes it possible to at least partially eliminate this problem, since the production potential of the machine is affected only by the time required to remove the articles from the machine in which they are produced, after which the machine can start producing new articles while the previous ones are undergoing sewing or joining at the same time.

[0008] On the other hand, the operation of transferring the product from the production machine to the joining station often requires the use of complex equipment, which must ensure extremely precise operation.

[0009] In the use of these devices, it has been found that the extraction of the article from the needle of the machine producing the article is particularly critical, since it significantly affects the total transfer time of the article and since it does not always ensure the required precision.

[0010] According to EP2250305 in the name of the same applicant, a method is known for performing closing at the axial ends of tubular knitted articles at the end of a production cycle of the article on a circular hosiery knitting machine or similar equipment, the method comprising initial steps of article production up to the execution of a final knitting loop at the axial end of the article opposite to the axial end at which knitting is started, the knitting loops of said final knitting loop being retained in the heads of the needles of the machine which form these knitting loops. Summary of the Invention

[0011] The object of the present invention is to provide a method for carrying out the closing of a tubular knitted article which improves the prior art in one or more of the aspects mentioned above.

[0012] Within this aim, an object of the present invention is to provide a method for closing a knitted tubular article that allows the productivity of the method and the device to be significantly improved.

[0013] Another object of the present invention is to provide a method for closing knitted tubular articles that allows reducing the cycle time while maintaining a very precise transfer operation.

[0014] Another object of the present invention is to provide a method for closing a knitted tubular article which is highly reliable, relatively easy to provide and cost-competitive. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Other characteristics and advantages of the invention will become more apparent from the description of a preferred but not exclusive embodiment of the method for closing a knitted tubular article according to the invention, which embodiment is illustrated by way of non-limiting example in the accompanying drawings, in which:

[0016] Figure 1 is a front elevation view of a circular hosiery knitting machine or similar apparatus;

[0017] Figure 2 During the initial steps of manufacturing a finished product Figure 1 a front view of a portion of a circular machine;

[0018] Figure 3 It is a step between the initial step of producing the product and the step of individually grasping the knitted loops with the help of a pickup element. Figure 1 A top view of a portion of a circular machine;

[0019] Figure 4 yes Figure 3 A front view of the machine part;

[0020] Figure 5 During the step of individually gripping the knitted loops with the help of a pick-up element Figure 1 a front view of a portion of a circular machine;

[0021] Figure 6 During the step of removing the product from the machine Figure 1 a front view of a portion of a circular machine;

[0022] Figure 7 yes Figure 6 Views of the machine in different partial cutaway angles;

[0023] Figure 8 During the step of positioning the product at the sewing station or the joining station 102 Figure 1 A top view of a portion of a circular machine;

[0024] Figure 9 yes Figure 8 Front view of the machine part. DETAILED DESCRIPTION

[0025] With reference to the accompanying drawings, the method according to the invention for closing a knitted tubular article at its axial ends at the end of its production cycle on a circular hosiery knitting machine 100 or similar device comprises:

[0026] – The initial steps of producing the article, which last until the execution of the final knitting pass at the axial end of the article opposite to the one where knitting is started, the loops of this final knitting pass being retained in the heads 123 c of the needles 123 of the machine 100 that form them.

[0027] – A step of individually gripping the knitted loops by means of a pick-up element 29 placed against the area of ​​the stem 123b of each needle 123 situated close to the latch 123d opposite the head 123c.

[0028] – a step of removing the article from the machine 100 for producing it, holding each knitting loop of the final knitting course formed by means of said pick-up element 29 .

[0029] - a step of positioning the product at the sewing or joining station 102;

[0030] - a step of transferring the knitted loops individually from the pick-up element 29 to the spiked portion of an annular handling device consisting of two half-annular portions, one of which can be turned relative to the other about a diametrical axis;

[0031] – a step of inverting the article held by the handling device;

[0032] - a step of superimposing, on the same spike portion of the processing device, each knitting loop of half the final knitting cycle on the corresponding knitting loop of the other half of the knitting cycle by turning one of the two semi-annular portions of the processing device relative to the other semi-annular portion through an arc of approximately 180° about the diametrical axis;

[0033] – the step of sewing or joining each pair of knitted loops that lie on top of each other;

[0034] - a step of removing the product from the treatment device, the product removal step comprising a first extraction preparation step, a second product extraction step and a third product transfer step.

[0035] The machine 100 has a yarn guide plate that can be raised and lowered, a cylinder 101, a stepper motor for moving the internal tube on command to bring the knitted fabric to the working position, a cylinder locking piston, a knitted fabric pusher piston, a pick-up arm 43 with a corresponding piston, a yarn guide plate, an internal knitted fabric lifting tube, an inverting piston, and a dial.

[0036] The method is characterized in that the first extraction preparation step comprises the following commands:

[0037] – Extraction start command;

[0038] – command to stop the machine;

[0039] – command to raise the yarn guide plate;

[0040] – Command to reboot the machine;

[0041] – Waiting for the command to position the cylinder 101 of machine 1;

[0042] – command to actuate the stepper motor of the internal tube to bring the knitted fabric to the working position;

[0043] – Set the command for positioning;

[0044] – command to actuate the cylinder locking piston in the working position;

[0045] – a command to actuate the piston of the knitwear pusher of the cylinder in working position;

[0046] – command to actuate the pickup arm piston in working position;

[0047] – a command to move the pick-up arm 43 to an intermediate state;

[0048] - a command to move the pickup arm 43 to a height for entering the machine;

[0049] – Waiting for the command for the yarn guide plate to enter the extraction position;

[0050] – Command to move the pickup arm 43 degrees to enter the machine;

[0051] - a command to move the pick-up arm 43 vertically to release the knitwear pusher of the cylinder;

[0052] – a command to move the pick-up arm 43 vertically in the intermediate position;

[0053] – If the cylinder locking piston is in active state, there is a command for the pick-up piston in inactive state;

[0054] – Waiting for orders;

[0055] – Command to move the pick-up arm 43 vertically to the pick-up height.

[0056] Commands including the following

[0057] – a command to stop the machine;

[0058] – Command to reboot the machine;

[0059] – Waiting for the command to position the cylinder;

[0060] – a command to actuate the stepper motor of the internal knitwear lifting tube in the working position;

[0061] – Set the command for positioning;

[0062] – command to lock the piston of the cylinder in working state;

[0063] Basically executed simultaneously.

[0064] Conveniently, the command that includes

[0065] – command to actuate the pickup piston in working position;

[0066] – a command to move the pick-up arm 43 to an intermediate state;

[0067] - a command to move the pickup arm 43 to a height for entering the machine;

[0068] Basically executed simultaneously.

[0069] Conveniently,

[0070] – Command to move the pickup arm 43 degrees to enter the machine;

[0071] - a command to move the pick-up arm 43 vertically to release the knitwear pusher of the cylinder;

[0072] – a command to move the pick-up arm 43 vertically in the intermediate position;

[0073] Executed after the yarn guide plate raising command has brought the yarn guide plate to the preset height.

[0074] The machine also has a knitting pusher of the cylinder, a stepper motor and an electric throttle valve associated with the suction device, a stepper motor for moving the sinker, and a stepper motor associated with the internal knitwear lifting tube.

[0075] The second step of extracting the product includes the following commands:

[0076] – a command to actuate the inactive stepper motor of the internal knitwear lifting tube;

[0077] - a command to actuate the stepper motor to the working height to pick up the product;

[0078] – command for the knitwear pusher of the cylinder in the working position;

[0079] – Waiting for orders;

[0080] – commands for actuating the stepper motors and electric throttle valves of the suction equipment;

[0081] – a command to move the pick-up arm 43 vertically to the extraction height;

[0082] – command to place the product on the pickup element;

[0083] – A command to activate the stepper motor to move the sinker to a safe height;

[0084] – a command to activate the stepper motor of the internal fabric lifting tube, which is in operation;

[0085] – command to actuate the inactive cylinder locking piston;

[0086] – Actuate the machine to level the needle from the heel exclusion position to the tuck stitch position.

[0087] Specifically,

[0088] – a command to actuate the inactive stepper motor of the internal fabric lifting tube; and

[0089] – A command to actuate the stepper motor to the working height to pick up the product;

[0090] Basically executed simultaneously.

[0091] Conveniently,

[0092] - a command to activate the stepper motor of the internal fabric lifting tube, which is in operation; and

[0093] – command to actuate the inactive cylinder locking piston;

[0094] Basically executed simultaneously.

[0095] Furthermore, the machine has a piston associated with the lower inverting unit, a sensor for transferring the product, a stepper motor and an electric throttle valve for the sewing machine, and a blower device for extracting the tubular product.

[0096] The third step of transferring the product includes the following commands:

[0097] – Waiting for the command to complete the leveling of the needle;

[0098] – Actuation of the command to reverse the piston;

[0099] – command to lower the dial in working position;

[0100] – an actuation command for the angular movement of the pickup arm 43 so as to bring it into the intermediate position;

[0101] – commands to control the sensors to transfer the tubular product;

[0102] – an actuation command for angular movement of the pick-up arm 43 to a predefined height;

[0103] - a command from the lower inverting unit to actuate the stepping motor and the electric throttle valve of the sewing machine to bring the lower inverting unit to a first throttle height;

[0104] – A command to actuate the stepper motor to tilt the inverting unit to a preset height;

[0105] – A command to actuate the stepper motor and the electric throttle valve to return the suction to zero;

[0106] – A command to actuate the stepper motor to tilt the lower inverting unit to a preset height;

[0107] – Waiting for orders;

[0108] – command to actuate the stepper motor to tilt the lower inverting unit to zero height;

[0109] – command for the blower device to facilitate the extraction of tubular products;

[0110] – a command to actuate the stepper motor and the electric throttle valve of the sewing machine to pump the lower inverting unit to the second throttle height;

[0111] – commands to the stepper motors to tilt the inverting unit to zero height;

[0112] – command to actuate the pickup arm 43 degrees to zero height;

[0113] – an actuation command to lock the inverting unit 130 in the inactive state;

[0114] – lowering the actuation command of an inactive dial;

[0115] – Waiting for orders;

[0116] Advantageously,

[0117] – an actuation command for the angular movement of the pickup arm to bring it to the intermediate position;

[0118] – commands to control the sensor to transfer the tubular product; and

[0119] – Actuation command to move the pick-up arm to a predefined angular height

[0120] Basically executed simultaneously.

[0121] Specifically, the steps include:

[0122] – Extraction start command;

[0123] – a command to stop the machine;

[0124] – command to raise the yarn guide plate;

[0125] and steps including:

[0126] – Command for picking up pistons in working state;

[0127] – Command to move the picking arm to the intermediate state;

[0128] – a command to move the pick-up arm to the height required to access the machine;

[0129] With respect to the first step of extraction, there is at least partial overlap during execution.

[0130] The movement of the machine to prepare the product for extraction is performed simultaneously with the above steps.

[0131] The use of stepper motors with closed-loop drives allows for increased movement speeds of the affected device.

[0132] The use of a closed-loop drive on the guide plate lifter allows further removal from the hosiery program of some of the idle rotation required to wait for the guide plate lifter to return to the starting state. Regarding the third step of transferring the articles, if a camera or alternative control sensor is installed, it is optimal to restart the machine immediately after the hosiery article has passed, without waiting for the control step using mechanical sensors.

[0133] In practice it has been found that the invention achieves the intended purpose and objectives and provides a method capable of significantly increasing the productivity of a machine.

[0134] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced by other technically equivalent elements.

[0135] In practice, the materials used may be any according to requirements and the state of the art, provided they are compatible with the specific use, or have shapes and dimensions.

[0136] The disclosures in Italian Patent Application No. 102020000023137 from which this application claims priority are incorporated herein by reference.

[0137] Where technical features mentioned in any claim are followed by reference numerals, the sole purpose of including these reference numerals is to increase the intelligibility of the claim and, therefore, these reference numerals do not have any limiting effect on the interpretation of each element exemplified by these reference numerals.

Claims

1. A method for closing a knitted tubular article at its axial ends at the end of a production cycle of the knitted tubular article on a circular hosiery knitting machine, the method comprising: - the initial steps of producing the article, said initial steps leading up to the execution of a final knitting pass at the axial end of said article opposite to the axial end where knitting is started, the loops of said final knitting pass being retained in the heads of the needles of the machine forming said loops; - a step of individually gripping the knitted loops by means of a pick-up element (29) arranged against the area of ​​the stem of each needle positioned close to the latch opposite the head; - a step of removing said article from said machine (100) for producing said article, holding each knitting loop of said final knitting course formed by means of said pick-up element (29); - a step of positioning the article at a sewing or joining station (102); - a step of transferring the knitted loops individually from the pick-up element (29) to the spiked portion of an annular handling device, the annular handling device consisting of two half-annular portions, one of which can be turned relative to the other about a diametrical axis; - a step of inverting said articles held by said handling means; - a step of superimposing, on the same spike portion of the processing device, each loop of the knitting of one half of the final knitting cycle on the corresponding loop of the knitting of the other half by turning one of the two semi-annular portions of the processing device relative to the other semi-annular portion through an arc of approximately 180° about the diametrical axis; – the step of sewing or joining each pair of knitted loops lying one on top of the other; - a step of removing the object from the handling device, wherein the step of removing the object comprises a first extraction preparation step, a second object extraction step and a third object transfer step, characterized in that the first extraction preparation step is executed by a control device and comprises the following commands: – Extraction start command; - a command to stop said machine (100); - a command to raise the yarn guide plate, wherein the yarn guide plate is provided with a closed-loop drive; - a command to restart said machine (100); – Waiting for the command to position the column (101); - a command to actuate the stepper motor of the inner tube to bring the knitted item to the working position, wherein said stepper motor is provided with a closed-loop drive; – Set the command for positioning; - a command to activate the locking piston of the cylinder (101) in the working state; - a command to activate the knitwear pusher piston of said cylinder in working condition; - a command to actuate the pickup piston in working position; – Command to move the picking arm to the intermediate state; - a command to move the pick-up arm to a height for entering the machine (100); - Waiting for the command for the yarn guide plate to enter the extraction position; - a command to angularly move the pickup arm to enter the machine (100); - a command to move the pick-up arm vertically to release the knitwear pusher piston of the cylinder; - a command to move the pick-up arm vertically in an intermediate position; - a command to actuate the inactive pickup piston if the cylinder locking piston is in the active state; – Waiting for orders; - a command to move the pick-up arm vertically to the pick-up height, Commands including the following - said command to stop said machine (100); - said command to restart said machine (100); - the command to wait for the cartridge to be positioned; - said command to actuate the stepper motor of the internal knitwear lifting tube in the working position; – the command to set the location; - a command to lock the piston of the cylinder in the working state; Basically executed simultaneously.

2. The method according to claim 1, characterized in that Commands including the following - a command for said pickup piston to be in working condition; - a command to move the pick-up arm to an intermediate state; - a command to move the pick-up arm to a height for entering the machine (100); Basically executed simultaneously.

3. The method according to claim 1, characterized in that Said: - a command to angularly move the pickup arm to enter the machine (100); - a command to move the pick-up arm vertically to release the knitwear pusher piston of the cylinder; - a command to move the pick-up arm vertically in the intermediate position; The method is executed after the yarn guide plate raising command brings the yarn guide plate to a preset height.

4. The method according to claim 1, wherein The second item extraction step is executed by the control device and includes the following commands: - a command to actuate the inactive stepper motor of the internal knitwear lifting tube; - a command to actuate the stepper motor to a working height to pick up the item; - a command for the knitwear pusher of the cylinder to be in the working position; – Waiting for orders; – commands for actuating the stepper motor and electric throttle valve of the suction device; - a command to move the pickup arm vertically to the extraction height; - a command to place said object on a pickup element; - a command to actuate the stepper motor to move the sinker to a safe height; - a command to activate the stepper motor of the internal textile lifting tube, which is in operation; - a command to actuate said cylinder locking piston which is in an inactive state; - a command to activate the machine (100) to level the needle from the heel exclusion position to the tuck stitch position; It is characterized in that - the command to actuate the stepper motor of the internal knitwear lifting tube, which is in an inactive state; - a command to actuate the stepper motor to a working height to pick up the item; Basically executed simultaneously.

5. The method according to claim 4, characterized in that - the command to actuate the stepper motor of the internal textile lifting tube in working order; and - a command to actuate the cylinder locking piston which is in an inactive state; Basically executed simultaneously.

6. The method according to claim 1, characterized in that The third item transfer step is executed by the control device and includes the following commands: – Waiting for the command to end the leveling of the needle; - a command to activate the lower inversion unit (130); – command to lower the dial in working order; - an actuation command for the angular movement of the pickup arm to bring it into an intermediate position; - a command to control the sensor to transfer the tubular article; - an actuation command to move the pickup arm angularly to a predefined height; - a command from the lower inverting unit (130) to actuate the stepping motor and the electric throttle valve of the sewing machine to bring the lower inverting unit to a first throttle height; - a command to actuate the stepping motor to tilt the lower inverting unit (130) to a preset height; - a command to actuate the stepper motor and the electric throttle valve to return their suction to zero; - a command to actuate the stepping motor to tilt the lower inverting unit (130) to a preset height; – Waiting for orders; - a command to actuate the stepper motor to tilt the lower inverting unit (130) to zero height; - a command for a blower device to facilitate the extraction of said tubular article; - a command to actuate the stepping motor and the electric throttle valve of the sewing machine to pump the lower inverting unit (130) to a second throttle height; - a command to the stepper motor to tilt the lower inverting unit (130) to zero height; - a command to actuate the pickup arm angle to zero height; - an actuation command to lock the lower inverting unit (130) in an inactive state; - lowering the actuation command of said dial in an inactive state; – Waiting for commands, The actuation command for angularly moving the pick-up arm to reach an intermediate position, the command for controlling the sensor to transfer the tubular article, and the actuation command for angularly moving the pick-up arm to a predefined height are executed substantially simultaneously.

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