JP7657912B2 - Method for closing an axial end of a knitted tubular product - Patents.com - Google Patents

Description

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 in a circular hosiery knitting machine.

As is well known, tubular knitted products, such as hosiery products, are typically produced on a circular hosiery machine and the tubular knitted product is removed from the circular hosiery machine with both axial ends of the tubular knitted product open.

In the case of hosiery products, after the hosiery products are removed from the knitting machine that produced them, the toe must be closed, which is done by a sewing machine or a linking machine.

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 manufactured on circular hosiery machines or the like.

The various techniques proposed so far can be divided into two main categories. The first category includes techniques based on the closure being carried out directly at the beginning or end of production on the knitting machine that produces the product. The second category includes techniques based on the closure being carried out at a sewing or linking station provided for this purpose and spaced apart from the knitting machine that produces the product.

The first category has the disadvantage that the closing operation requires a certain amount of time, during which the knitting machine cannot produce new products, thus significantly limiting the productivity of the knitting machine.

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, and which can then produce a new product whilst still sewing or linking the previous product.

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 that must ensure very precise operations.

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.

From EP 2 250 305 in the name of the same applicant, a method is known for closing a knitted tubular product at one of its axial ends at the end of a production cycle, for example in 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 the axial end of the product where knitting began, and holding the knitting loops of the last knitting row on the heads of the needles of the knitting machine which formed the knitting loops.

The intent of the present invention is to provide a method for closing a knitted tubular product that can improve upon the background art in one or more of the above-mentioned aspects.

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 apparatus.

Another object of the present invention is to provide a method for closing knitted tubular products that allows for reduced cycle times while maintaining a highly accurate transfer motion.

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.

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

Further features and advantages of the present 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 present invention, shown in the accompanying drawings, which are non-limiting examples.

FIG. 2 is a front view showing a circular hosiery knitting machine and the like. 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; FIG. 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. FIG. 4 is a front view showing the mechanical portion of FIG. 3 . 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. 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; FIG. 7A-7C show the circular hosiery knitting machine in the state of FIG. 6 from different partial cross-sectional views. 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. FIG. 9 is a front view showing the mechanical portion of FIG. 8 .

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 the 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 the region of the axis 123b of each needle 123, 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 said 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 and which can be turned around a diametric axis, one of which in relation to the other,
- turning over the 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;
and removing the product from the processing device , the step of removing the product from the knitting machine including a first pull-out preparation step, a second product pull-out step, and a third product transfer step .

The knitting machine 100 is equipped with a yarn guide plate that can be raised and lowered, a cylinder 101, a step motor for moving according to the command of the inner tube to bring the knitted product to the working position, a cylinder fixed piston, a knitted product extrusion piston, a pickup arm 43 with a corresponding piston, a yarn guide plate, a knitted product raising inner tube, an inside-out piston, and a dial.

The method further comprises the steps of:
- Start withdrawal command,
- a command to stop the knitting machine,
- a 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 a working position;
- a command to establish that the placement has been carried out,
- a command for actuating the cylinder fixed piston in the working state,
- a command for actuating the product ejection piston of the cylinder in the working state,
- a command for actuating the piston of the pick-up arm in the working state,
a command to move the pick-up arm 43 to an intermediate position,
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 for angularly shifting the pick-up arm 43 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 active state,
- a wait command; and - a command to move the pick-up arm 43 vertically to the pick-up height.

- a command to stop the knitting machine,
- a command to restart the knitting machine,
- a command to wait for the placement of a cylinder,
- a command for activating the step motor of the inner tube in the working position,
- a command for establishing that the positioning has been achieved; and - a command for actuating the cylinder fixed piston in the working state, said command being substantially simultaneous.

Conveniently,
- a command for actuating the piston of the pick-up arm in the working state,
commands are issued substantially simultaneously, including a command for moving the pick-up arm 43 to an intermediate position, and a command for moving the pick-up arm 43 to the entry height of the knitting machine.

Conveniently,
- a command for angularly shifting the pick-up arm 43 for entry into the knitting machine,
a command for the vertical movement of the pick-up arm 43 in order to release the product-extrusion piston of the cylinder, and a command for the vertical movement of the pick-up arm 43 to an intermediate position, after the command for raising the yarn guide plate has brought it to a preset height.

The knitting machine further includes 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 rising inner tube.

The second product extraction step of extracting the product includes:
- 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,
- commands for operating the stepper 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 for activating the step motor of the inner tube for raising the train in the working state;
- a command to activate a non-activated cylinder fixed piston;
- Commands to operate the machine to level the needles from the heel exclusion position to the tuck knitting position.

especially,
- commanding the step motor of the inactive product lift inner tube to be activated, and - commanding the step motor to be activated to the working height to pick up the product substantially simultaneously.

Conveniently,
a command to activate the step motor of the inner tube for raising the formation in the working state, and a command to activate the cylinder fixed piston in the non-working state, substantially simultaneously.

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

The third product transfer process for transferring the product includes:
- A command to wait for the completion of needle height adjustment;
- a command for activating the lower turn-over unit;
- A command to lower the dial in working condition,
a command to move the pick-up arm 43 angularly to bring it to an intermediate position;
- instructions for controlling the sensor to transfer the tubular product;
an actuation command for angularly moving the pick-up arm 43 to a predetermined height;
- a command from the lower turning-over unit to activate 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 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 flipping unit at zero height;
- instructions for activating a blower to facilitate withdrawal of the tubular product;
a command to activate the stepper 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 flipping unit at zero height;
a command for angularly moving the pick-up arm 43 at zero height;
an activation command for fixing the lower turning-over unit 130 in an inactive state;
- an activation command to lower the inactive dial;
- A wait command.

Advantageously,
- an actuation command for angularly moving the pick-up arm to bring it to an intermediate position;
- a command to control the sensor to transfer the tubular product, and - an actuation command to angularly move the pick-up arm to a predetermined height, substantially simultaneously.

In particular, the first step of preparing the drawer is
- Start withdrawal command,
- a command to stop the knitting machine, and - a command to raise the yarn guide plate,
- a command for actuating the piston of the pick-up arm in the working state,
- a command to move the pick-up arm to an intermediate position; and - a command to move the pick-up arm to an entry height into the knitting machine,
At least partially overlap during execution.

Machine movements to prepare the product for withdrawal occur simultaneously with the above steps.

The use of a step motor with a closed loop driver makes it possible to increase the movement speed of the operating device.

By employing a closed loop driver for the yarn guide plate lifting device, it is further 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 the product is transferred, if 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.

Indeed, it has been found that the present invention achieves its intended aims and objectives by providing a method that can significantly increase the productivity of a knitting machine.

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.

In fact, the materials used and the associated shapes and dimensions can be anything depending on the requirements and current technology, so long as the materials used are suitable for the particular application.

The disclosures in Italian Patent Application No. 102020000023137, from which this application claims priority, are hereby incorporated by reference.

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

Claims (6)

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,
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,
- commands for vertically moving said pick-up arm to a pick-up height,
- 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 a fixed piston of said cylinder in a working state. - 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 said pick-up arm to an entry height into said circular hosiery knitting machine . - 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,
3. The method according to claim 1 or 2, wherein a command for vertically moving the pick-up arm to said intermediate position is executed after bringing said thread guide plate to a preset height by a command for raising said thread guide plate. 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 the stepper motor to a working height for picking up the knitted product ,
- 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,
- an instruction for placing a 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;
- instructions for operating said circular hosiery knitting machine to bring the needles from the heel exclusion position to the same height as the tuck knitting position,
- said command for activating the step motor of the inactive inner tube of the train lift;
The method according to any one of claims 1 to 3, wherein said commands for actuating said stepper motors to a working height for picking up a knitted product are executed substantially simultaneously. - said command for activating the step motor of said train-lifting inner tube in the working state,
The method of claim 4 , further comprising: - executing the commands to activate the stationary pistons of the inactivated cylinders substantially simultaneously. 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,
- including a standby command,
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.

Images