The present invention relates to a support and control device for circular knitting machines. In particular, the invention relates to a support and control device characterized by a specific structure and characterized by a peculiar integration of its component apt to interact with needles and selectors of a knitting machine.
Moreover, the present invention relates to a circular knitting machine comprising such device.
The present invention falls into the technical field of circular knitting machines for knitted items, seamless knitted items, hosiery items and the like.
In the present text the wording "knitting machine" generally means a circular knitting machines apt to manufacture knitted items and provided with at least one needle-holding unit or needle-holding cylinder turnably mounted in a supporting structure of the machine and supporting in suitable sliding compartments (or needle seats) a plurality of needles moving parallel to an axis of rotation of the needle-holding cylinder so as to produce a knitted fabric. The needle-holding unit further comprises a corresponding plurality of needle selectors, wherein each selector is typically coupled to a respective needle and phased with it, i.e. vertically aligned along the respective sliding compartment. Each selector is configured so as to interact with the respective needle and in particular to guide its longitudinal movement (along the sliding compartment) by lifting and lowering it so as to perform certain knitting operations.
Moreover, the knitting machine is provided with a plurality of yarn feeding points or yarn "feeds", in which the needles of the machine are supplied with yarn. This knitting machine can be e.g. single or double needlebed. Circular knitting machines can comprise a variable number of feeds, e.g. 2, 4, 6, 8 or more yarn feeds.
In the field of circular knitting machines, several modes for controlling needles and needle selectors are known.
Typically, a series of components and devices for controlling needles and needle selectors are mounted to the knitting machine on each yarn feed. These components and devices comprise at least: a stitch cam, which interacts with the needle butts for moving them longitudinally (up and down) in the respective sliding compartment; a selector cam, which interacts with the selector butts for moving them longitudinally (up and down) in the respective sliding compartment, so that they impart a given longitudinal movement to the respective needle. Basically, on each feed the movement (in particular the lifting movement) of each needle is the combination of the longitudinal motion imparted by the stitch cam directly to the needle and by the motion imparted by the selector cam to the respective selector and through it to the needle.
The needle butts are placed in a point of the longitudinal development of the needles, and so as to sequentially catch the stitch cam profile. In a similar manner, the selector butts are placed in a point of the longitudinal development of the selectors, and so as to sequentially catch the selector cam profile.
Known knitting machines typically comprise for each feed also a selecting device, which consists of a box-shaped block or body carrying a series of levers individually actuated by respective actuators and configured so as to interact with suitable selector teeth. As a matter of fact, each selector is provided with at least a respective tooth protruding outside the needle-holding unit.
In a state-of-the-art solution shown by way of example, the levers are arranged in a vertical row, whereas the selector teeth are placed at different heights along the respective longitudinal development, and in particular progressively along a group of sequential selectors, thus forming a global sawtooth-shaped development of the teeth around the needle-holding unit. Each lever interacts with the teeth placed at the same height only, therefore when the needle-holding unit is rotating, due to the progressive development of the teeth of sequential selectors, the levers periodically abut onto a tooth arranged at their same height, with an actuating sequence of the levers along the vertical row of the levers themselves (e.g. from the bottom lever to the top lever and so on from the beginning).
At the state of the art, the actuators actuating the levers can exploit for instance a piezoelectric technology, which makes use of special ceramics changing their geometrical shape during the passage of electric current. In this solution, each ceramic acts upon a respective lever so as to selectively shift it between a first position, in which it does not get in contact with the selector tooth, and a second position, in which it touches the selector tooth and pushes it inside the needle-holding unit (using the technical jargon, the lever pushed the tooth and "drowns" the selector). Basically, in the first position the lever does not interfere with the selector tooth, which maintains its radial position (with respect to the axis of the needle-holding cylinder) resulting in its butt entering the path of the selector cam, and thus the selector makes a longitudinal movement transmitted to the respective needle: in this condition, the selector intervenes in the definition of the travel of the respective needle and thus of its law of motion. Conversely, in the second position, the lever interferes with the selector tooth by changing the radial position of the latter so that its butt does not enter the path of the selector cam; therefore, the selector is not led to make longitudinal movements and does not cooperate with the respective needle: in this condition, the selector does not intervene in the definition of the travel of the respective needle. Therefore, each needle makes a different trajectory depending on whether its selector has been guided by the selector cam, which depends in its turn on whether the lever has interacted with the selector tooth.
Typically, the selecting devices at the state of the art are complete commercial components, produced by specialist manufacturers and mounted to the knitting machine. These devices are thus connected to the control unit of the knitting machine, which manages their operation.
In the field of knitting machines, it is known about the use of structures enabling to place the various devices (stitch cams, selector cams, selecting devices) in the correct positions for interacting with needles and selectors and for performing knitting operations.
A first solution makes use of a supporting block to be placed on the frame of the knitting machine and to which one or more stitch cams, one or more selector cams and one or more selecting devices have to mounted. These blocks, in the technical jargon referred to as "sections" or "boxes", also "cam boxes" or "cam sections", are basically worked pieces receiving thereon the stitch cams, the selector cams and in particular the box-shaped block or body of the selecting device, which comprises inside the levers and the piezoelectric actuators. The elements mounted to the block are placed in a given manner with respect to the needle-holding unit.
Knitting machines comprise a plurality of the aforesaid blocks, typically one or more for each yarn feed; the number of blocks can also be very large, e.g. on knitting machines with large diameters or with a large number of yarn feeds.
In a further solution at the state of the art, the box-shaped blocks or bodies are of the selecting devices are mounted to a plate, which in its turn is secured to the frame of the knitting machine. Moreover, there is an additional ring - typically placed above the selecting devices - supported by uprights and developing around the needle-holding unit: the stitch cams and the selector cams are secured onto this ring. Basically, in this case there is not a plurality of distinct blocks for supporting the various devices, but these are mounted on different levels based on the type they belong to.
Other examples of methods and apparatuses are known.
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The Applicant has found that known knitting machines, in particular as far as components and devices controlling the needles and needle selectors, are not without drawbacks and can be improved under various aspects.
A typical drawback of known solutions consists in the difficult mounting of the various devices for controlling needles and selectors. As a matter o fact, in the state-of-the-art solution making use of a supporting block (the aforesaid "section" or "box"), it is necessary to mount the stitch cams, the selector cams and the selecting device individually to the supporting block and then mount each supporting block to the machine frame. In the technical solution making use of plates and additional ring, the selecting devices have to be mounted to the plates and these to the frame of the knitting machines, and moreover the needle cams and the selector cams have to be mounted to the additional ring, which is in its turn placed and secured with respect the frame.
All these mounting operations of the needle and selector control devices are typically complex and require much time and manpower. Moreover, every mounting operation can lead to an erroneous mounting, which results in an erroneous positioning of the device with respect to the needle-holding unit. This is a huge drawback in the field of knitting machines, since an erroneous mounting of the cams and of the selecting devices - even though not so serious - leads to an erroneous interaction with the needles and with the selectors of the needle-holding unit, and thus to knitting mistakes or inaccuracies.
For these mistakes, at the state of the art the control devices for the needles and the selectors require complex and difficult operations involving adjustments and configurations with respect to the needle-holding unit.
A further drawback of known solutions consists in the large overall dimensions of the structure apt to place the various control devices for needles and selectors. As a matter of fact, both the supporting blocks and the plates as well as the additional ring have quite large dimensions and occupy considerable volumes around the needle-holding unit.
A further drawback of known solutions consists in the fact that, due to the overall dimensions of the structures apt to place the various control devices for needles and selectors, it is hard to attain in the knitting machine a large number of feeds, and in general it is difficult to integrate many control devices.
A further drawback of known solutions consists in the difficult execution of maintenance operations on control devices for needles and selectors, in particular to the complex structures for mounting these to the frame of the knitting machine.
Under these circumstances, the aim underlying the present invention in its various aspects and/or embodiments is to provide a support and control device which can obviate one or more of the drawbacks referred to above.
A further aim of the present invention is to provide a support and control device which can accurately position the control devices for needles and selectors, and in particular the stitch cams, the selector cams and the selecting devices, with respect to the needle-holding unit.
A further aim of the present invention is to provide a support and control device which can simplify the mounting and/or maintenance operations of the control devices for needles and selectors.
A further aim of the present invention is to provide a support and control device characterized by a high operating reliability and/or by a lower susceptibility to failures and malfunctions.
A further aim of the present invention is to provide a support and control device for circular knitting machines characterized by a simple and rational structure.
A further aim of the present invention is to provide a support and control device characterized by low manufacturing costs as far as offered performance and quality are concerned.
A further aim of the present invention is to create alternative solutions to the state of the art for carrying out support and control devices for circular knitting machines and/or open new design possibilities.
A further aim of the present invention is to provide a support and control device for circular knitting machines which can enable a new design of the control devices for needles and selectors.
A further aim of the present invention is to provide a support and control device for circular knitting machines characterized by an innovative structure and configuration with respect to the state of the art.
These and other possible aims, which shall appear better from the following description, are basically achieved by a support and control device according to one or more of the appended claims, each one being considered alone (without those depending on it) or in any combination with the other claims, and according to the following aspects and/or embodiments, variously combined, also with the aforesaid claims. In a first aspect thereof, the invention relates to a support and control device for circular knitting machines for knitted or hosiery items, designed to be mounted in a circular knitting machine having a rotating needle-holding unit and carrying a plurality of needles and a corresponding plurality of selectors for these needles.
In one aspect, the device comprises at least one support body equipped at least with:
In one aspect, the device comprises:
In one aspect, said selecting units for controlling the plurality of needle selectors comprise a plurality of levers, each one being configured so as to interact with the butts of a respective plurality of needle selectors, and a corresponding plurality of piezoelectric actuators, each piezoelectric actuator being configured so as to selectively move the respective lever at least between a first position, in which the lever interacts with the butts of the respective plurality of selectors, and a second position, in which the lever does not interact with the butts of the respective plurality of selectors.
In one aspect, said support body is made in one piece or as a single piece. In one aspect, the support body is monolithic. In one aspect, said at least one cam associated with said second seat is a stitch cam for controlling the needles.
In one aspect, said plurality of piezoelectric actuators is directly associated with, or directly engages, one or more surfaces of said first seat of the device body. In one aspect, said plurality of piezoelectric actuators is directly mounted inside the first seat of the device body.
In one aspect, said plurality of piezoelectric actuators is without a box-shaped housing body, the actuators being directly housed in said first seat.
In one aspect, the levers of said plurality of levers are directly associated with, or directly engage, one or more surfaces of said first seat of the device body.
In one aspect, the levers of said plurality of levers are directly mounted inside the first seat of the device body and are moving with respect to the device body.
In one aspect, said first seat and said second seat are obtained directly in said device body.
In one aspect, the device further comprises:
In one aspect, said at least one further cam associated with said third seat is a selector cam for controlling the selectors of the knitting machine.
In one aspect, said support body directly housing said selecting units acts as a support also for a stitch cam and/or one or more selector cams. In one aspect, said third seat is obtained directly in said device body.
In one aspect, the needles are moving parallel to an axis of rotation of the needle-holding unit so as to produce a knitted fabric.
In one aspect, the device is designed to be placed on a needle-holding unit or needle-holding cylinder of the knitting machine.
In one aspect, the mounting portion is configured so as to allow the device to be directly mounted to a supporting structure of a circular knitting machine.
In one aspect, the piezoelectric actuators comprise a ceramic element which can be curved or extended as a result of an electric voltage, so as to place the respective lever in said first position or in said second position. In one aspect, the selecting units comprise electric and electronic components for the operation of the piezoelectric actuators.
In one aspect, the support body extends longitudinally or vertically between a lower side and an upper side, opposed to said lower side.
In one aspect, the support body comprises a front side, configured so as to face - with the device being mounted to the knitting machine - a needle-holding unit of the knitting machine, preferably in a radial, outer position with respect to an axis of rotation of the needle-holding unit.
In one aspect, said first seat is defined (or obtained) on said front side.
In one aspect, the first seat comprises a cavity turning inwards from said front side to the inside of the support body.
In one aspect, said cavity is at least partially open at least on said front side.
In one aspect, said second seat is defined (or obtained) on said front side.
In one aspect, said third seat is defined (or obtained) on said front side.
In one aspect, the support body is made of metallic material, preferably aluminum. In an alternative aspect aspect, the support body is made of plastic material.
In one aspect, the stitch cam is configured so as to interact with the butts of the moving needles as a result of the rotation of the needle-holding unit.
In one aspect, the selector cam is configured so as to interact with the butts of the moving selectors as a result of the rotation of the needle-holding unit.
In one aspect, the body of the device is a box or section of a circular knitting machine, configured so as to support the control units associated with a feed or yarn feeding point on which the yarn is supplied to the machine needles.
In one aspect, the support device is configured so as to comprise the selecting units, the stitch cams and the selector cams associated with a single feed or yarn feeding point on which the yarn is supplied to the machine needles.
In one aspect, the stitch cam defines a guiding path for the moving needles (in particular for the needle butts), apt to globally guide the movement thereof parallel to the axis of rotation of the needle-holding cylinder.
In one aspect, the selector cam defines a guiding path for the moving selectors (in particular for the selector butts), apt to globally guide the movement thereof parallel to the axis of rotation of the needle-holding cylinder.
In an aspect thereof, the present invention relates to a circular knitting machine for knitted or hosiery items comprising at least one support and control device according to one or more of the aforesaid aspects and/or claims.
In one aspect, the knitting machine comprises:
In one aspect, the knitting machine further comprises at least one support and control device according to any one of the aspects and/or claims, wherein the mounting portion of the support body is mounted to said supporting structure, wherein said first seat houses the selecting units of a feed and said second seat houses said at least one cam for controlling the needles or for controlling the selectors of the same feed. In one aspect, each feed of said plurality of feeds comprises a respective stitch cam and a respective selector cam, said second seat housing said stitch cam and said third seat housing said selector cam of the same feed.
In one aspect, said needle-holding unit is a needle-holding cylinder or a needle-holding plate.
In one aspect, the knitting machine comprises a plurality of support and control devices, each of them being associated with a respect feed.
In one aspect, the circular knitting machine comprises a plurality of support and control devices placed circumferentially around said needle-holding unit, preferably each one on a respective feed.
In one aspect, the support and control devices are preferably angularly spaced from one another in a uniform manner around the axis of rotation.
In one aspect, the knitting machine comprises a plurality of support and control devices which are all basically identical to one another.
Each one of the aforesaid aspects of the invention can be considered alone or in combination with any one of the claims or of the other aspects as described.
Further characteristics and advantages shall be more evident from the detailed description of some embodiments, among which also a preferred embodiment, which are exemplary though not exclusive, of a support and control device according to the present invention. This description shall be made below with reference to the accompanying drawings, provided to a merely indicative and therefore non-limiting purpose, in which:
With reference to the mentioned figures, the numeral 1 globally designates a support and control device for circular knitting machines according to the present invention. Generally, the same numeral is used for identical or similar elements, if applicable in their variants of embodiment.
The figures do not show the knitting machine for which the device 1 is designed; such a machine can be of conventional type and known per se. Generally, it should be assumed that a circular knitting machine, for knitted or seamless knitted items or for hosiery items, typically comprises a supporting structure, at least one needle-holding unit or needle-holding cylinder or plate turnably mounted in this supporting structure, a plurality of needle supported by the needle-holding cylinder and moving parallel to an axis of rotation of the needle-holding cylinder so as to produce a knitted fabric, and a corresponding plurality of selectors for these needles, which are also supported by the needle-holding cylinder and each one is phased with a respective needle. The needle-holding cylinder can have a diameter varying depending on textile needs; accordingly, the needle-holding unit can be a needle-holding plate. Moreover, the knitting machine comprises a plurality of yarn feeding points or "feeds", in which the needles of the machine are supplied with yarn. These feeds are placed circumferentially around the needle-holding unit and angularly spaced from one another.
From the point of view of knitting technology, the operation of the whole knitting machine is not described in detail, since it is known in the technical field of the present invention.
The device 1 comprises at least one support body 2 equipped at least with:
The device further comprises:
The selecting units 20 for controlling the plurality of needle selectors comprise a plurality of levers 21, each one being configured so as to interact with the butts of a respective plurality of needle selectors, and a corresponding plurality of piezoelectric actuators. Each piezoelectric actuator is configured so as to selectively shift the respective lever 21 at least between a first position, in which the lever interacts with the butts of the respective plurality of selectors, and a second position, in which the lever does not interact with the butts of the respective plurality of selectors.
Basically, the selecting units 20 are piezoelectric selecting units.
In a preferred embodiment, shown by way of example in the figures, the support body 2 is made in one piece or a single piece. In other words, the support body 2 is monolithic, preferably not made as a composition of parts mounted to one another but as one block.
Preferably, as shown by way of example in the figures, the aforesaid at least one cam, associated with the second seat 5, is a stitch cam 30 for controlling the needles.
In the field of knitting machines, the wording "stitch cam" means an element designed to be placed on a feed so as to define the height of each needle moving on the stitch cam on this feed. When the needle moves in a feed, it receives the yarn so as to form the knitted fabric: the formation of the knitted fabric takes place for each yarn on a knitting plane placed vertically on top of the needle-holding cylinder. The stitch cam causes a vertical movement of the needles along a direction parallel to the longitudinal development of the needle (and parallel to the axis of rotation of the cylinder). The vertical movement of each needle, managed by the stitch cam, is such as to vertically position the upper end (or head) of the needle at a desired height, so that the needle receives the yarn from the feed which the stitch cam is associated with, and then to lower it so as to form a stitch. The stitch cam defined a guiding path, which intercepts the rotating needles: this causes a vertical shift of the needle according to a given law of motion defined by the guiding path itself. Depending on the vertical position of the stitch cam, the vertical height (in particular the minimum height) reached by the needle in the feed varies: as a result, also the length (or width) of the stitch (or loop) thus made varies, since this width depends on the distance between the knitting plane and the lower point reached by the needle head. Typically, the stitch cams interact with a specific portion of the needle, the so-called butt. With the knitting machine running, i.e. with the cylinder rotating, all the needles sequentially get through - on each cam - the respective stitch cam of the feed and interact with it.
Going back to the selecting units 20, preferably the aforesaid plurality of piezoelectric actuators is directly associated with, or directly engages, one or more surfaces of the first seat 4 of the body of the device. In the embodiment shown in the figures, levers and piezoelectric actuators are in direct contact with, i.e. directly mounted to the support body 2, in particular to the first seat 4.
Preferably, the first seat 4 and the second seat 5 are obtained directly in the body 2 of the device or are defined directly on the device body. Preferably, the first and the second seat represent respective portions of the device body, i.e. they are defined on these respective portions. The first and the second seat can be structured as a suitable surface of the device body, machined so as to house (or enable the mounting of) the selecting units and of the stitch cam or the cam.
Preferably, the device 1 further comprises:
Preferably, as shown by way of example in the figures, the aforesaid further cam, associated with the third seat 6, is a selector cam 40 for controlling the selectors of the knitting machine.
Preferably, the third seat 6 is obtained directly in the body 2 of the device or is defined directly on the body 2 of the device.
Preferably, as in the embodiment shown by way of example in the figures, the device 1 further comprises:
Preferably, the mounting portion 3 is configured so as to allow the device 1 to be directly mounted to a supporting structure of a circular knitting machine.
As far as the selecting units 20 are concerned, some cooperating modes between the levers 21 and the selectors are described below.
First of all, each selector can be selected or not by the respective lever, depending on the effect on the selector determined by the position of the lever, which can be selected between said first and second position.
In a first mode, which corresponds to the most common mode in the field, the selector operates "passively": according to this mode, in the first position (or OFF position or inactive position or low lever) the lever does not get in contact with the tooth of the selector and thus does not push it inside the cylinder. In this case, the selectors remains outside (normally outside the cylinder with respect to the axis of rotation of the cylinder) and therefore interacts with the selector cam, which is placed outside and facing the cylinder. The selector interacts with the selector cam engaging a path of this selector cam, and therefore interacts with the respective needle, lifting and guiding it in its sliding compartment. Thus, in this case the OFF position of the lever corresponds to the activation of the selector.
In the second position (or ON position or active position or high lever) the lever gets in contact with the tooth of the selector and thus pushes it inside the cylinder: in this case the selector does not interact with the selector cam (i.e. does not get into the path of the selector cam) and therefore does not interact with the needle, i.e. does not lift and guide it into its sliding compartment. Thus, in this case the ON position corresponds to the deactivation of the selector.
This operation of the selector is therefore referred to as "passive".
In a second mode, the selector operates "directly": according to this mode, in the first position (or OFF position or inactive position or low lever) the lever does not get in contact with the tooth of the selector and thus the latter does not interact with the selector cam (i.e. does not get into the path of the selector cam) and therefore does not interact with the needle. In this case the OFF position corresponds to the deactivation of the selector.
In the second position (or ON position or active position or high lever) the lever gets in contact with the tooth of the selector and thus the latter interacts with the selector cam (i.e. engages the path of the selector cam) and therefore interacts with the needle. In this case the ON position corresponds to the activation of the selector.
The levers of the selecting units enable to control the selectors so as to define at least two technical modes for the needles of the knitting machine, i.e. two operating positions for the needles: non-operating and knitting (or operating).
Typically, the activation of the selector corresponds to the activation of the respective needle, which is therefore shifted to the operating position (or knitting position), whereas the deactivation of the selector corresponds to the non-activation of the respective needle, which therefore remains in its non-operating position.
Preferably, the piezoelectric actuators comprise a ceramic element which can be curved or extended as a result of an electric voltage, so as to place the respective lever 21 in one of the aforesaid first position or second position. The selecting units further comprise electric and electronic components for the operation of the piezoelectric actuators.
Preferably, the support body 2 extends longitudinally (or vertically) between a lower side 11 and an upper side 12, opposed to said lower side.
Preferably, the aforesaid mounting portion 3 is defined on the lower side 11 of the support body and is configured so as to be removably mounted to a supporting structure, e.g. a frame, of the knitting machine. Preferably, the support body 2 comprises a front side 13, configured so as to face - with the device being mounted to the knitting machine - a needle-holding unit of the knitting machine, preferably in a radial, outer position with respect to an axis of rotation of the needle-holding unit.
Preferably, the first seat 4 is defined (or obtained) on the front side 13.
Preferably, the first seat 4 comprises a cavity turning inwards from the front side 13 to the inside of the support body 2. Preferably, the cavity is at least partially open at least on the front side 13. Preferably, the second seat 5 is defined (or obtained) on the front side 13.
Preferably, the second seat 5 comprises a surface portion configured so as to allow at least one stitch cam 30 to be mounted; this surface portion is suitably machined and can comprise one or more mounting holes.
Preferably, the third seat 6 is also defined (or obtained) on the front side 13. Preferably, the third seat comprises a surface portion configured so as to allow at least one selector cam 40 to be mounted; this surface portion is suitably machined and can comprise one or more mounting holes.
Preferably, also the fourth seat 7 is defined (or obtained) on the front side 13. Preferably, the fourth seat 7 comprises a surface portion configured so as to allow at least one further selector cam 50 to be mounted; this surface portion is suitably machined and can comprise one or more mounting holes.
Basically, preferably all the seats, i.e. the first 4, the second 5, the third 6 and the fourth seat 7, are positioned on the front side 13 of the device body, so as to face - with the device mounted - the needle-holding unit and perform their respective control function for needles and selectors.
Preferably, the first seat 4 is positioned in a proximal position with respect to the lower side 11 of the support body 2, and the second seat 5 is positioned in a proximal position with respect to the upper side 12 of the support body.
Preferably, the third seat 6 is longitudinally placed between the first seat 4 and the second seat 5. Preferably, the fourth seat 7 is placed between the first seat 4 and the lower side 11 of the support body. Preferably, as shown by way of example in the figures, the second seat 5, the third seat 6, the first seat 4 and, if present, the fourth seat 7 develop vertically on the front side 13 in sequence from the upper side 12 to the lower side 11.
Preferably, the support body is made of metallic material, e.g. aluminum. As an alternative, the support body can be made of plastic material.
Preferably, the first seat 4, the second seat 5 and the third seat 6 respectively house the selecting units 20 for controlling the plurality of selectors, the stitch cam 30 and the selector cam 40 in a removable manner. Preferably, the device can further comprise a fifth seat configured so as to house an intermediate selector cam for controlling intermediate selectors of the knitting machine. These intermediate selectors are similar to the selectors and are placed longitudinally between a respective selector and a respective needle inside a sliding compartment. Basically, each intermediate selector acts upon the respective needle and contributes, together with the respective selector, to define the law of motion of the needle, i.e. the vertical positioning of the needle during the rotation of the needle-holding cylinder. The intermediate selectors are typically controlled by a respective cam, which is indeed the intermediate selector cam.
In a possible embodiment (not shown), the device comprises a mounting unit (or plate) configured so as to be placed between a stationary structure of the knitting machine and the support body and to enable an adjustment of the position of the support body with respect to the needle-holding unit.
Preferably, the mechanical coupling between support body and mounting unit grants the support body a certain degree of translational freedom with respect to the mounting unit, preferably along a radial direction moving to and away from the needle-holding unit.
Preferably, this adjustment of the position of the support body comprises at least an adjustment of the radial distance of the support body (and therefore of the levers and/or of the cams) from the needle-holding unit, in particular from the axis of rotation of the needle-holding unit.
Preferably, the mechanical coupling between support body and mounting unit allows the support body to slide with respect to the mounting unit, along a radial direction with respect to the needle-holding unit. Preferably, the mounting unit comprises a first portion configured so as to be mounted in a given position of the stationary structure of the machine, so that the mounting unit is integral with the stationary structure and uniquely positioned with respect thereto.
The first portion is preferably defined on a lower side of the mounting unit.
Preferably, the mounting unit comprises a second portion configured so as to receive the mounting portion of the support body and to movably mount the support body to the mounting unit.
Preferably, the mechanical coupling between the mounting portion of the support body and the second portion of the mounting unit is of skid or slide type and enables a shift of the support body with respect to the mounting unit (and therefore with respect to the stationary structure of the knitting machine), preferably along a radial direction basically perpendicular to the axis of rotation of the needle-holding unit.
The second portion is preferably defined on an upper side of the mounting unit.
Preferably, the mounting unit comprises clamping means configured so as to stably secure the position of the support body after adjusting its radial distance from the needle-holding unit.
The support body can thus be slidingly mounted to a plate, the latter stiffly secured to the frame of the knitting machine; this allows to adjust the radial position of the support body and, as a result, the radial position of the levers of the selecting units. This is particularly important since during the mounting and setup of the knitting machine, the radial position of the levers must be such as to precisely contact the butts of the selectors during the passage of the latter. As a matter of fact, were the levers radially at too short a distance from the cylinder, they might incorrectly interfere with the butts (e.g. hitting them), whereas conversely, were the levers radially at too large a distance from the cylinder, they might incorrectly control the butts (e.g. they might not contact the butts).
Preferably, the body of the device is a box or section of a circular knitting machine, configured so as to support the control units associated with a feed or yarn feeding point on which the yarn is supplied to the machine needles.
Preferably, the support device is configured so as to comprise the selecting units, the stitch cams and the selector cams associated with a single feed or yarn feeding point on which the yarn is supplied to the machine needles.
In a possible embodiment, shown by way of example in the figures, the support body 2 comprises a pair of first seats 4a and 4b, configured so as to respectively house first selecting units 20a and second selecting units 20b for controlling the plurality of selectors of the needles of the knitting machine. Preferably, the first seats 4a and 4b of said pair of first seats are both defined on the front side 13 and are laterally placed one beside the other. Preferably, each first seat of the pair of first seats comprises a respective cavity turning inwards from the front side to the inside of the support body. Preferably, the respective cavity of each first seat of the pair of first seats is at least partially open at least on the front side. Preferably, the support body has an inner partition placed between the two first seats of the pair of first seats and configured so as to define and separate the cavities of the two first seats from one another.
Preferably, the two first seats of the pair of first seats are basically identical to each other.
Preferably, the device comprises the aforesaid first selecting units 20a and the aforesaid second selecting units 20b for controlling the plurality of selectors of the needles of the knitting machine, wherein the first selecting units 20a are housed in or associated with a first seat 4a of the pair of first seats, and the second selecting units 20b are housed in or associated with a second seat 4b of the pair of first seats.
Preferably, the first selecting units and the second selecting units are basically identical to each other from a structural point of view.
The presence of first selecting units and second selecting units, i.e. of a double series of levers actuated by a double series of piezoelectric actuators, associated with one support body and designed for the same feed, allows to control the selectors so as to define three technical modes for the needles of the knitting machine, i.e. three operating positions for the needles: non-operating, knitting (or operating), stopped. Preferably, the first seat 4 (or each first seat of the pair of first seats) is laterally open at least on a lateral face 15, or side, of the support body. Preferably, the support body 2 comprises a wall 16 (or panel or carter) configured so as to laterally close the first seat 4, housing therein the selecting units 20, and to define a portion of the lateral face 15. Preferably, the two first seats of the pair of first seats are open on opposite lateral faces, or sides, of the support body. Preferably, the support body 2 comprises two walls 16 (or panels or carters) each configured so as to laterally close the respective first seat, housing therein the respective selecting units, and to define a portion of the respective lateral face.
Preferably, the aforesaid wall 16 is a structural element configured so as to strengthen the support body and prevent the support body from bending due to the absence of material from the first seat 4 on the respective lateral face 15.
Concerning this point, it should be pointed out that the device body undergoes in use stresses generated by the interaction between the needles and the selectors with the body itself. As a matter of fact, the device body is secured to a supporting structure of the knitting machine and faces the needle-holding unit; the rotation of the latter causes the passage of the needles in the stitch cam of the device and the interaction of the selectors with the selecting units (levers) of the device. This gives rise to a series of strains and stresses on the body of the device, in particular, in the sense of rotation of the needle-holding unit. The particular shape of the device body according to the present invention is preferably characterized by the cavity turning inwards from the front side to inside of the support body and defining the aforesaid first seat. This cavity can weaken the device body, which can bend or deform as a result of the aforesaid strains and stresses.
In the embodiment in which the first seat 4 is laterally open at least on a lateral face 15, or side, of the support body, the bending action involves in particular the portions of the body above and below the cavity (i.e. the first seat). This bending can be due to a compression of the body, which tends to bring the portions of the body above and below the cavity near each other (basically "narrowing" the opening of the cavity on the lateral face), or to a traction, which tends to bring the portions of the body above and below the cavity away from each other (basically "widening" the opening of the cavity on the lateral face).
Therefore, the aforesaid wall 16, in order to represent a structural element apt to strengthen the support body and prevent the body itself from bending, is stiffly secured to the support body so as to avoid deformations under compression and under traction, and to keep the size of the support body, and in particular of the cavity defining the first seat, constant.
Preferably, the wall 16 is placed on a respective lateral face of the body and is secured above to a proximal portion of the body with respect to the upper side 12 of the body itself, and below to a proximal portion of the body with respect to the lower side 11 of the body itself.
Preferably, the wall 16 has an upper tooth configured so as to be secured to a proximal portion of the body with respect to the upper side 12 of the body itself, and a lower tooth configured so as to be secured to a proximal portion of the body with respect to the lower side 11 of the body itself.
Preferably, the wall 16 is secured above to the support body by means of one or more screws, inserted into dedicated slots of the body itself, and is secured below to the support body by means of further one or more screws, inserted into dedicated slots of the body itself. These screws enable a mounting of the wall ensuring a friction hold, between the screws themselves and the support body.
In a possible embodiment, the wall 16 is secured to the support body, both above and below, by means of one or more stop pins (or rivets) inserted (preferably forced) into suitable seats (typically holes) of the support body. These stop pins enable a mounting of the wall ensuring a size coupling hold, between the pins themselves and the aforesaid seats of the support body.
The aforesaid upper and lower teeth and/or the aforesaid screws and/or the aforesaid stop pins allow to obtain a stiff and stable mounting of the wall to the support body, so that the wall represents a structural element configured so as to strengthen the support body and prevent the thrusts and stresses acting upon the support body from generating therein bending or deformations.
In one embodiment, not shown, the support body comprises one first seat 4 only, which is laterally open on both lateral faces 15, or sides, of the support body. In this case, the support body 2 preferably comprises two walls 16 configured so as to laterally close the first seat 4, housing therein the selecting units 20, each wall 16 defining a portion of the respective lateral face 15.
In a possible embodiment, not shown, the device can comprise a base configured so as to house and carry thereon the support body of the support and control device, said base being - with the device mounted to the knitting machine - vertically placed between the support body and a frame of the knitting machine. Preferably, the base corresponds to the aforesaid mounting unit.
Preferably, the aforesaid base is configured so as to enable the adjustment of the position of the device body with respect to the needle-holding unit of the circular knitting machine. More preferably, the base allows to adjust the radial position of the device body with respect to the needle-holding unit, i.e. the radial distance of the device body from the axis of rotation of the needle-holding unit. The position adjustment preferably occurs by means of coupling means placed between the device body and the base. These coupling means can comprise a translational coupling, e.g. a rectilinear guide, which allows to shift the device body towards or away from, along a radial direction, the axis of rotation of the needle-holding unit. Preferably, the aforesaid coupling means between the device body and the base can enable further adjustments of the position of the device body on a plane orthogonal to the axis of rotation of the needle-holding unit. Preferably, the aforesaid base is configured so as to carry a pair of support and control devices, one beside the other, so that the devices are associated with two adjacent feeds or yarn feeding points of the knitting machine; each device supports the control units (i.e. selecting units, stitch cams and/or selector cams) associated with a respective feed.
Preferably, the two devices associated with a single base are basically identical to each other.
As shown by way of example in the figures, the device 1 comprises, preferably on a rear portion of the support body 2 opposite the front side 13, connecting means configured so as to be connected, e.g. by means of a data cable, to a control unit of the knitting machine, so that the latter can manage the operation of the device, and in particular the operation of the selecting units, more specifically of the piezoelectric actuators. The connecting means preferably comprise a plurality of electric/electronic connectors (e.g. one or more connectors coupled to each piezoelectric actuator), which can be removably connected to the aforesaid data cable.
A circular knitting machine for knitted or hosiery items according to the present invention is described below. This machine comprises at least:
The knitting machine further comprises at least one aforesaid support and control device, having the mounting portion of the support body mounted to the supporting structure and carrying the selecting units, the stitch cam and/or the selector cam. Preferably, the knitting machine comprises a plurality of support and control devices placed circumferentially around said needle-holding unit, wherein each of them is associated with a respective feed. Preferably, the support and control devices are angularly spaced from one another in a uniform manner around the axis of rotation. Preferably, the knitting machine comprises a plurality of support and control devices which are all basically identical to one another.
The invention thus conceived can be subjected to various changes and variants, all of which fall within the scope of the claims, and the components mentioned here can be replaced by other technically equivalent elements, falling within the scope of the claims.
The present invention can be used both on new and on existing machines, in the latter case replacing traditional structures for mounting components and devices for controlling needles and selectors. The invention achieves important advantages. First of all, the invention allows to overcome at least some of the drawbacks of known technique.
Moreover, the device of the present invention is structured so as to enclose and integrate into one device the functions of support of the needle cams and of the selector cams and at the same time of support of the selecting units. In particular, as the selecting units are concerned, the device of the present invention is characterized in that it comprises a support body being suitably machined so as to mount and position the levers, the piezoelectric actuators and the electronics required for controlling these actuators.
Basically, in the present device the support body directly housing the selecting units also acts as a support for the stitch cams and the selector cams. Therefore, the device represents a box or section for circular knitting machines, configured so as to support the control units associated with a feed, and enables to eliminate the complex support structures used at the state of the art. In particular, with respect to the solution making use of supporting blocks (the so-called "cam boxes" or "cam sections"), the present invention allows to avoid the structural weakening of the cam box due to the large hollow designed to house the box-shaped block or body of the selecting device. The device of the present invention is stiffer and structurally better than the solutions at the state of the art. Moreover, with respect to the solution making use of plates and additional ring, the present invention allows to completely eliminate the additional ring.
A further advantage of the device of the present invention consists in that it can accurately position the control devices for needles and selectors, and in particular the stitch cams, the selector cams and the selecting devices, with respect to the needle-holding unit. Moreover, the device of the present invention allows to eliminate the complex and difficult operations involving the adjustment and configuration of the control devices for needles and selectors with respect to the needle-holding unit.
Moreover, the device of the present invention allows to reduce the overall dimensions of the supporting portion for stitch cams and selectors and of the selecting units with respect to the solutions at the state of the art. In particular, the vertical dimensions can be highly reduced, even to the half or more, with respect to known supporting structures (making use of a block (cam box or cam section) or of an intermediate ring). Also the lateral (or horizontal) dimensions - i.e. the size of the device between the lateral walls - are highly reduced with respect to the solutions at the state of the art, thanks to the integration of the control devices for needles and selectors directly into the support body of the device.
Therefore, the device of the present invention - having small overall dimensions both in vertical and above all in lateral (or horizontal) direction - allows to increase the number of devices that can be positioned on each feed, and therefore allows to increase the selecting points inside a single feed. The selecting points allow to select in a given manner the movement of the needles and of the selectors: a larger number of selecting points therefore allows to impart a larger number of possible movements to the needles and to the selectors, and thus to obtain a higher variety of knitting operations that can be executed by the machine.
In addition or as an alternative, the small overall dimensions (in particular in a lateral direction of the device) allow - the type of knitting machine being the same - to increase the number of feeds of the machine itself, since all the control devices for needles and selectors are integrated into the device of the present invention and therefore occupy a smaller volume.
Moreover, the device of the present invention allows to simplify the mounting and maintenance operations of the control devices for needles and selectors.
Furthermore, the device highly improves the access to the needle-holding cylinder also with the knitting machine mounted, and does not require to dismount many components in case of maintenance of the needle-holding cylinder.
Moreover, the device of the present invention is characterized by a high operating reliability and by a lower susceptibility to failures and malfunctions.
Moreover, the device of the present invention is characterized by a competitive cost and by a simple and rational structure.
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.