Method for closing an axial end of a knitted tubular product - Patents.com

Abstract

A method for closing the axial ends of a knitted tubular product at the end of a production cycle on a circular hosiery knitting machine includes: producing the product up to the last knitted row, holding the knitted loops of the last knitted row on the heads of the knitting machine needles that formed the knitted loops of the last knitted row, individually grasping the knitted loops with a pickup device having pickup elements positioned on the opposite side of the head and adjacent to the area of ​​the axis of each needle located immediately adjacent to the latch, removing the product by holding each loop of the formed last knitted row with the pickup elements, placing the product in a sewing station, individually transferring the loops from the pickup elements to spikes of a circular device consisting of two half-circles, turning the product held by the processing device inside out, overlapping half of the loops of the last knitted row with the corresponding loops of the other half of the last knitted row by inversion with the same spikes of the processing device, sewing the overlapped pairs of knitted loops together, and removing the product from the processing device. The product removing step includes a first step for preparing the product for withdrawal, a second step for withdrawing the product, and a third step for transferring the product. A specific sequence of instructions for the various steps is provided.

Description

[Technical field]

[0001] The present invention relates to a method for closing a knitted tubular product at its axial ends at the end of a production cycle, such as on a circular hosiery knitting machine. [Background technology]

[0002] As is well known, tubular knitted articles, such as hosiery articles, are typically produced on a circular hosiery machine and removed from the circular hosiery machine with both axial ends of the tubular knitted article being open. Summary of the Invention [Problem to be solved by the invention]

[0003] In the case of hosiery products, after the hosiery products are removed from the knitting machine on which they were produced, the toe must be closed, which is performed by a sewing machine or a linking machine.

[0004] Because such operations require additional machinery and labor, which significantly impacts the overall manufacturing costs of hosiery products, various techniques have been proposed to automate the closure of the toes of hosiery products, and more generally, to automate the closure of the axial ends of tubular knitted products produced on circular hosiery knitting machines or the like.

[0005] The various techniques proposed so far can be divided into two main categories: the first category includes techniques based on closure carried out directly at the beginning or end of production on the knitting machine that produces the product, and the second category includes techniques based on carrying out the closure in a sewing or linking station that is spaced apart from the knitting machine that produces the product and that is dedicated to this purpose.

[0006] The first category has the drawback that the closing operation requires a certain time during which the machine cannot produce new products, thus significantly limiting the productivity of the machine.

[0007] The second category, to which the technology described for example in Italian patent no. 1300622 belongs, makes it possible to at least partially eliminate this problem, since the production capacity of the knitting machine is only penalized in terms of the time required to remove the product from the machine which produced it, after which the machine can produce a new product whilst still sewing or linking the previous product.

[0008] On the other hand, the operations for transferring the product from the knitting machine to the linking station often require the use of complex equipment which must ensure very precise operations.

[0009] When using these devices, the pick-up of the product from the needles of the knitting machine which produced it proves to be particularly critical, since it has a significant influence on the overall transport time of the product and it is not always possible to ensure the necessary precision.

[0010] From EP 2 250 305 in the name of the same applicant is known a method for closing a knitted tubular product at one of its axial ends at the end of a production cycle, for example on a circular hosiery knitting machine, which method comprises an initial step of producing the product up to the last knitting row at the axial end opposite to that of the product from which knitting began, and of retaining the knitting loops of said last knitting row on the needle heads of the knitting machine which formed said knitting loops.

[0011] It is an intention of the present invention to provide a method for closing a knitted tubular product, which is able to improve upon the background art in one or more of the above mentioned aspects.

[0012] Within this spirit, the object of the present invention is to provide a method for closing knitted tubular products, which makes it possible to significantly increase the productivity of the method and the device.

[0013] Another object of the present invention is to provide a method for closing knitted tubular products which allows shortening the cycle time while maintaining a very accurate transfer motion.

[0014] Another object of the present invention is to provide a method for closing knitted tubular products that is highly reliable, relatively easy to provide and competitively priced. [Means for solving the problem]

[0015] This aim, as well as these and other objects which will become more apparent hereinafter, are achieved by a method for closing a knitted tubular product according to claim 1, optionally comprising one or more of the features of the dependent claims.

[0016] Further features and advantages of the invention will become more apparent from the description of preferred, but not exclusive, embodiments of the method for closing a knitted tubular product according to the invention, shown by way of non-limiting example in the accompanying drawings, in which: [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a front view showing a circular hosiery knitting machine and the like. [Diagram 2] 2 is a front view of a portion of the circular hosiery knitting machine of FIG. 1 during an early stage of producing a product. [Diagram 3] 2 is a plan view of a portion of the circular hosiery knitting machine of FIG. 1 at an intermediate step between the initial step of producing a product and the step of individually gripping the knitted loops by the pick-up elements; FIG. [Figure 4] FIG. 4 is a front view showing the mechanical portion of FIG. [Diagram 5] 2 is a front view of a portion of the circular hosiery knitting machine of FIG. 1 during the process of individually gripping the knitted loops by the pick-up elements; FIG. [Figure 6] 2 is a front view of a portion of the circular hosiery knitting machine of FIG. 1 during the process of removing the product from the machine. [Figure 7] 7A-7C show the circular hosiery knitting machine in the state of FIG. 6 from a different partial cross-sectional perspective. [Figure 8] 2 is a plan view of a portion of the circular hosiery knitting machine of FIG. 1 during the process of placing the product at a sewing or linking station 102. [Figure 9] FIG. 9 is a front view showing the mechanical portion of FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] With reference to the drawings, the method for closing a knitted tubular product at its axial ends at the end of a production cycle, such as in a circular hosiery knitting machine 100, according to the invention, comprises: - an initial step of producing a product up to the last knitting row at the axial end opposite to the axial end of the product where knitting has started, and holding said knitted loop on the head 123c of the needle 123 of the knitting machine 100 which formed the knitted loop of the last knitting row; - gripping the knitted loops individually by means of a pick-up element 29 arranged in contact with the area of ​​the axis 123b of each needle 123 located opposite the head 123c and immediately adjacent to the latch 123d; - removing the product from the knitting machine 100 on which it was produced by holding each knitting loop of the last knitted row formed by the pick-up element 29; - placing the product at a sewing or linking station 102; - transferring the knitted loops individually from the pick-up element 29 to the spike of an annular processing device, which is made up of two semi-annular parts, one of which can be turned around a diametric axis with respect to the other semi-annular part; - turning over the product held by the processing device; - overlapping the loops of one half of the last knitted row with the corresponding loops of the other half of the last knitted row by means of identical spikes of the processing device, by inverting one of the two semi-annular parts of the processing device relative to the other semi-annular part through an arc of substantially 180° about a diametric axis; - sewing or linking pairs of knitted loops superimposed on one another; - Processing The process of removing the product from the processing equipment Have The process of removing the product from the knitting machine includes a first pull-out preparation process, a second product pull-out process, and a third product transfer process. .

[0019] The knitting machine 100 includes a yarn guide plate which can be raised and lowered, a cylinder 101, a step motor for moving the knitted product in response to a command from the inner tube to bring the knitted product to a working position, a cylinder fixed piston, a knitted product pushing piston, a pickup arm 43 having a corresponding piston, a yarn guide plate, a knitted product lifting inner tube, an inside-out piston, and a dial.

[0020] This method includes the steps of: - Start withdrawal command, - a command to stop the knitting machine, - command to raise the thread guide plate, - a command to restart the knitting machine, a command to position the cylinder 101 of the knitting machine 100 in a standby state, - a command to operate the stepper motor of the inner tube to bring the train into the working position; - a directive to set that the placement has been made; - a command for actuating the cylinder fixed piston in the working state, - a command to activate the piston of the cylinder in the working state; - a command to activate the piston of the pick-up arm in the working state, - a command to move the pick-up arm 43 to an intermediate state, - a command to move the pick-up arm 43 to the entry height of the knitting machine, - a command to wait for the thread guide plate to be in the withdrawn position; - a command to move the pick-up arm 43 angularly for entry into the knitting machine, - a command to move the pick-up arm 43 vertically to release the product ejection piston of the cylinder, - a command to move the pick-up arm 43 vertically to an intermediate position, - a command to activate the piston of the inactive pick-up arm if the cylinder fixed piston is in the working state, - Standby command, and - command to move the pick-up arm 43 vertically to the pick-up height It is characterized in that it includes

[0021] - a command to stop the knitting machine, - a command to restart the knitting machine, - Command to wait for cylinder placement, - a command to activate the step motor of the inner tube in the working position, - a command to establish that the placement has been made, and - Command to activate the cylinder fixed piston in working state and performing instructions including:

[0022] Conveniently, - a command to activate the piston of the pick-up arm in the working state, - a command to move the pick-up arm 43 to an intermediate state, and - a command to move the pick-up arm 43 to the entry height of the knitting machine and performing instructions including:

[0023] Conveniently, - a command to move the pick-up arm 43 angularly for entry into the knitting machine, - a command to move the pick-up arm 43 vertically to release the product ejection piston of the cylinder, and - A command to move the pickup arm 43 vertically to an intermediate position This is done after the thread guide plate has been brought to a preset height by a command to raise the thread guide plate.

[0024] The knitting machine further comprises a cylinder knitted product pusher, a step motor and an electric throttle valve associated with the suction device, a step motor for moving the sinker, and a step motor associated with the knitted product lift inner tube.

[0025] The second product extraction process for extracting the product is - a command to activate the step motor of the inactive train lift inner tube; - a command to activate the stepper motor to the working height to pick up the product; - a command for activating the knitting pusher of the cylinder in the working position; - A standby command, - a command for operating the step motor and the electric throttle valve of the suction device; - a command to move the pick-up arm 43 vertically to the pull-out height; - instructions for placing the product on the pick-up element; - a command to activate the stepper motor to move the sinker to a safe height; - a command to activate the step motor of the inner tube of the ascending train in the working state; - a command to activate a non-activated cylinder fixed piston; - A command to operate the knitting machine and bring the needles from the heel exclusion position to the tuck knitting position at the same height. Includes.

[0026] especially, - a command to activate the step motor of the inactive train lift inner tube, and - Command to activate the stepper motor to the working height to pick up the product are performed substantially simultaneously.

[0027] Conveniently, - a command to operate the step motor of the inner tube of the ascending train in the working state, and - Command to activate the cylinder fixed piston in the inactive state are performed substantially simultaneously.

[0028] The knitting machine further comprises a piston associated with the lower turning unit, a sensor for shifting the product, a sewing machine stepper motor and an electric throttle valve, and a blower for drawing the tubular product.

[0029] The third product transfer process is - A command to wait for the needle height adjustment to finish, - a command to activate the lower flipping unit; - A command to lower the dial in working condition, - a command to angularly move the pick-up arm 43 to bring the pick-up arm 43 to an intermediate position; - instructions for controlling a sensor to transfer the tubular product; - an actuation command for angularly moving the pickup arm 43 to a predetermined height; - a command from the lower turning-over unit to operate the step motor and the electric throttle valve of the sewing machine to bring the sewing machine to a first throttle height; - a command to activate the stepper motor to tilt the lower flipping unit at a preset height; - a command to zero the stepper motor and the electric throttle valve of the suction device; - a command to activate the stepper motor to tilt the lower flipping unit at a preset height; - A standby command, - a command to activate the stepper motor to tilt the lower flip unit at zero height; - a command to activate the blower to facilitate withdrawal of the tubular product; - a command to operate the step motor and the electric throttle valve of the sewing machine to suck the lower inside-out unit to a second throttle height; - a command to activate the stepper motor to tilt the lower flip unit at zero height; - a command for angularly moving the pick-up arm 43 at zero height; - an activation command for fixing the lower turn-over unit 130 in an inactive state; - An activation command to lower the inactive dial, and - Standby command and Includes.

[0030] Advantageously, - an actuation command for angularly moving the pickup arm to bring the pickup arm to an intermediate position; - instructions for controlling a sensor to transfer the tubular product; and - An operation command to move the pickup arm to a specified height are performed substantially simultaneously.

[0031] In particular, the first drawer preparation step is related to - Start withdrawal command, - a command to stop the knitting machine, and - Command to raise the thread guide plate and - a command to activate the piston of the pick-up arm in the working state, - a command to move the pick-up arm to an intermediate state, and - Command to move the pick-up arm to the entry height of the knitting machine The process includes: At least partially overlap during execution.

[0032] Machine movements to prepare the product for withdrawal occur simultaneously with the steps described above.

[0033] The use of stepper motors with closed loop drivers has made it possible to increase the speed of movement of the working device.

[0034] By employing a closed loop driver for the yarn guide plate lifting device, it has further been possible to eliminate from the hosiery program the multiple idle revolutions required to wait for the yarn guide plate lifting device to return to the starting state. With reference to the third product transfer step, where a video camera or alternative control sensor is installed, the restart of the knitting machine immediately after the passage of the hosiery product is optimized without waiting for the mechanical sensor control step.

[0035] Indeed, it has been found that the present invention achieves its targeted aims and objects by providing a method which can significantly increase the productivity of a knitting machine.

[0036] The invention thus conceived is susceptible to numerous modifications and variations, all of which are within the scope of the appended claims, and all of the details may further be replaced by other technically equivalent elements.

[0037] In fact, the materials used, and the associated shapes and dimensions, can be anything depending on the requirements and current state of the art, so long as the materials used are suitable for the particular application.

[0038] The disclosures in Italian Patent Application No. 102020000023137 from which this application claims priority are incorporated herein by reference.

[0039] Although technical features described in any claim are followed by reference signs, these reference signs are included only to enhance the clarity of the claims and therefore do not limit in any way the interpretation of the respective elements identified by such reference signs as examples.

Claims

1. 1. A method for closing an axial end of a knitted tubular article at the end of a production cycle, such as in a circular hosiery machine, comprising: - an initial step of producing a knitted product at the axial end opposite to the axial end of the knitted product where knitting has started, up to the last knitting row, and holding said knitted loops on the heads of the needles of a circular hosiery knitting machine which has formed the knitted loops of said last knitting row; - gripping said knitted loops individually by means of pick-up elements arranged in contact with the area of ​​the axis of each needle, located opposite said head and immediately adjacent to the latch; - removing the knitted product from the circular hosiery knitting machine on which it was produced by holding each knitted loop of the last knitted row formed by the pick-up element; - placing said knitted product at a sewing or linking station; - transferring the knitted loops individually from said pick-up elements to the spikes of an annular processing device, which consists of two semi-annular parts, one of which can be turned around a diametric axis relative to the other, - turning over the knitted product held by the processing device; - overlapping, with identical spikes of the processing device, the knitted loops of one half of the last knitted row on the corresponding knitted loops of the other half of the last knitted row by inverting one of the two semi-annular parts of the processing device relative to the other semi-annular part through an arc of substantially 180° about the diametric axis; - sewing or linking pairs of knitted loops superimposed on one another; - removing the knitted product from the processing device; having The step of removing the knitted product from the circular hosiery knitting machine includes a first step of preparing to pull out the knitted product, a second step of pulling out the knitted product, and a third step of transferring the knitted product, The first drawer preparation step is executed by a control means, - Start withdrawal command, a command to stop the circular hosiery knitting machine, - a command to raise the thread guide plate with a closed loop driver, a command to restart the circular hosiery knitting machine, - a command to wait for the placement of a cylinder, - a command to operate a stepper motor with a closed-loop driver of the inner tube to bring the assembly into a working position; - a command to establish that the placement has been carried out, a command for actuating the fixed piston of said cylinder in the working state, - a command for activating the product ejection piston of said cylinder in the working state, - a command for actuating the pick-up piston in the working state, - a command to move the pick-up arm to an intermediate state, - a command to move the pick-up arm to an entry height into the circular hosiery knitting machine, a command to wait for the thread guide plate to be in the withdrawal position, - a command to move the pick-up arm angularly for entry into the circular hosiery knitting machine, - a command to move the pick-up arm vertically to release the product ejection piston of the cylinder, - a command to move the pick-up arm vertically to an intermediate position, a command to activate an inactive pick-up piston when the fixed piston of said cylinder is in said working state, - Standby command, - a command to move said pick-up arm vertically to the pick-up height Including, - said command to stop said circular hosiery knitting machine, - said command for restarting said circular hosiery knitting machine, - said command to wait for placement of said cylinder, - said command for activating a step motor of said inner tube in a working position, - said command to establish that the placement has been carried out, - said command for actuating the fixed piston of said cylinder in the working state; 4. A method for substantially simultaneously executing instructions including:

2. - a command for activating said pick-up piston in the working state, - a command to move the pick-up arm to the intermediate state, - a command to move the pick-up arm to an entry height into the circular hosiery knitting machine The method of claim 1 , further comprising substantially simultaneously executing instructions including:

3. - a command to move the pick-up arm angularly for entry into the circular hosiery knitting machine, - a command to move the pick-up arm vertically to release the product ejection piston of the cylinder, - a command to move the pick-up arm vertically to the intermediate position 3. The method according to claim 1, further comprising the step of: a) executing a command for raising the thread guide plate after bringing the thread guide plate to a preset height;

4. The second knitted product pulling step is executed by the control means, - a command to activate the step motor of the inactive train lift inner tube, - a command to operate said stepper motor to a working height for picking up a unit; - a command to activate the knitting pusher of said cylinder in the working position, - Standby command, - commands for operating the stepper motor and the electric throttle valve of the suction device, - a command to move the pick-up arm vertically to the pull-out height, - instructions for placing the knitted item on said pick-up element, - a command to activate the stepper motor to move the sinker to a safe height, - a command to activate the step motor of the inner tube for lifting the formation in the working state, a command to activate the fixed piston of said cylinder, which is inactive; - a command to operate said circular hosiery machine so that the needles are levelled from the heel exclusion position to the tuck knitting position; Including, - said command for activating the step motor of the inactive inner tube of the train lift; - said command for operating said stepper motor to a working height for picking up a unit; The method according to any one of claims 1 to 3, wherein the steps are carried out substantially simultaneously.

5. - said command for activating the step motor of said train-lifting inner tube in the working state, - said command for actuating a fixed piston of said cylinder which is in an inactive state; The method of claim 4 , wherein:

6. The third knitted product transfer step is executed by the control means, - A command to wait for the needle height adjustment to finish, - a command to activate the lower turn-over unit, - command to lower the dial in working condition, - an actuation command for angularly moving the pick-up arm to bring it to an intermediate position, - instructions for controlling the sensor to move the tubular structure, - an actuation command for angularly moving said pick-up arm to a predetermined height, - a command from said lower turning unit to operate the stepper motor and the electric throttle valve of the sewing machine to bring it to a first throttle height; - a command to activate the stepper motor to tilt the lower turning unit at a preset height, - a command to zero the stepper motor and the electric throttle valve of the suction device, - a command to activate the stepper motor to tilt the lower turning unit at a preset height, - Standby command, - a command to activate the stepper motor to tilt the lower turning unit at zero height, - instructions for activating the blower to facilitate the drawing of the tubular arrangement; a command to activate the stepper motor and the electric throttle valve of the sewing machine to suck said lower inside-out unit to a second throttle height; - a command to activate the stepper motor to tilt the lower turning unit at zero height, - a command for moving said pick-up arm angularly at zero height, - an activation command for fixing said lower turning-over unit in an inactive state, - an activation command to lower the inactive dial, - Standby command Including, 6. The method according to claim 1, wherein the actuation command for angularly moving the pick-up arm to bring the pick-up arm to an intermediate position, the command for controlling the sensor to transfer a tubular braid, and the actuation command for angularly moving the pick-up arm to a predetermined height are executed substantially simultaneously.

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