Circular weft knitting machine and control method of circular weft knitting machine

Abstract

A circular weft knitting machine comprises a base (2) and a knitting assembly (3) installed on the base (2). The knitting assembly (3) comprises a needle holding mechanism (4), the needle holding mechanism (4) is provided with a gear (8) coaxial with the central axis (X-X) of the needle holding mechanism (4), and the gear (8) is provided with a plurality of teeth (18 '). A main motor (9) is operably connected to the gear (8) for determining the rotation of the needle holding mechanism (4) about the central axis (X-X) and relative to the base (2). The proximity sensors (17A, 17B) are fixedly mounted relative to the base (2) for detecting the passage of the teeth (18 ') of the gear (8) and / or the passage of the teeth (18) of the auxiliary wheels (15A, 15B) operably paired with the gear (8) and emitting corresponding signals (S1, S2). The electronic control unit (19) receives and processes the signals (S1, S2) from the proximity sensors (17A, 17B) and controls mechanism and / or functional parameters of the machine (1) according to the signals (S1, S2).

Description

Technical Field

[0001] The present invention relates to a circular weft knitting machine. The present invention also relates to a control method for a circular weft knitting machine. In particular, the present invention relates to detecting the position and / or rotation speed of a circular weft knitting machine so as to control its operation. Background Art

[0002] As is known, circular weft knitting machines can be used to manufacture various types of textiles, for example for manufacturing clothing or other types of textiles.

[0003] The circular weft knitting machine comprises a knitting assembly, on which at least one needle holding mechanism (needle holding cylinder and / or needle holding plate) is mounted, on which a group or more tissue needles arranged along a circular path are provided to form a corresponding circular needle bed. The knitting assembly also comprises means for controlling the movement of the knitting needles to weave a fabric which is at least partially tubular. These means comprise an action triangle arranged around the needle holding cylinder and / or facing the needle holding plate and operably connected to the knitting needles. The knitting assembly is provided with a plurality of knock-over sinkers, which are arranged to cooperate with the knitting needles to form a knitted fabric. The knock-over sinkers are movably arranged in radial seats in an annular body (sinking crown seat) arranged around the needle holding cylinder. The circular knitting machine comprises a base, which constitutes the bearing structure of the knitting machine. Specifically, the base constitutes the ground bearing mechanism of the knitting machine. The base is also used to support the knitting assembly mounted on the base. During the knitting process, the tubular fabric produced by the knitting assembly continuously moves downward, i.e., descends into the lower space defined by the base structure and is collected by a special device. The knitting machine is equipped with a main motor, which is usually mounted on a base plate and connected to the needle holding mechanism through a belt and gear transmission device, and determines the rotation of the needle holding mechanism around its central axis. The rotation of the needle holding mechanism determines the movement of the knitting needle and other machine mechanisms through interaction with the cam to achieve the purpose of weaving fabrics. For example, documents WO2020250075A1 and WO2020212817A1 under the name of the same applicant describe such a machine.

[0004] In known machines such as those mentioned above, the rotation of the main motor (which drives the needle holding mechanism) is detected by an encoder, and the position and speed of the needle holding mechanism are determined by control electronics, thereby controlling the machine's mechanisms and parameters during the fabric production process based on this position and speed. Summary of the invention

[0005] With regard to the above-mentioned circular weft knitting machines, the Applicant has noted that in order to precisely control and guide the machine mechanism in order to produce a quality fabric and / or provide the desired properties, the exact position and / or speed of the needle holding mechanism must be instantly known and communicated to the control electronics.

[0006] The Applicant has found that machines of known type detect the position and / or speed of the needle-holding mechanism indirectly, but this detection is not accurate and / or may be subject to errors, since the detection is carried out on the main motor, which is connected to the needle-holding mechanism via a transmission. Due to the presence of one or more belts, possible play in the transmission and / or a flexible transmission, the signal sent to the electronic control unit does not provide the exact position and / or speed of the needle-holding mechanism. If maintenance and / or replacement of parts are not carried out regularly and in a timely manner, the deviation between the actual position and / or speed of the needle-holding mechanism and the signal received by the control electronics will also increase during the service life of the machine, since the flexible belt will deform over time and / or the play of the transmission parts will increase.

[0007] Therefore, the object of the present invention is to propose a circular weft knitting machine and a control method for a circular weft knitting machine that can overcome the above-mentioned limitations and disadvantages.

[0008] A basic object of the present invention in its various aspects and / or embodiments is to provide a circular weft knitting machine that can accurately control the movement of its mechanisms and / or operate according to set functional parameters, thereby producing high-quality fabrics that meet the characteristics of the fabric to be manufactured.

[0009] Another object of the present invention is to provide an accurate and reliable control method for a circular weft knitting machine.

[0010] Another object of the present invention is to provide a circular weft knitting machine and a control method which can maintain such reliability and accuracy for a long time.

[0011] According to the following aspects and / or embodiments and / or the appended claims, the circular weft knitting machine and the control method of the circular weft knitting machine provided by the present invention can basically achieve the above-mentioned and other objects.

[0012] In a first aspect, the invention relates to a circular weft knitting machine comprising:

[0013] A base that can be placed on the ground;

[0014] A knitting assembly mounted on a base, the knitting assembly comprising: a needle holding mechanism having a central axis and a plurality of grooves arranged around the central axis, a plurality of knitting needles being mounted in the plurality of grooves, an action device being fixedly mounted on the base, being operable to be paired with or suitable for being paired with the knitting needles, and being able to determine or allow the knitting needles to move along the grooves so as to form a knitted fabric through the knitting needles, the needle holding mechanism comprising a gear coaxial with the central axis and having a plurality of teeth;

[0015] A main motor, operatively connected to the gear of the needle holding mechanism, for determining the rotation of the needle holding mechanism about the central axis and relative to the base;

[0016] at least one proximity sensor fixedly mounted relative to the base, for detecting the passage of teeth of the gear and / or the passage of teeth of at least one auxiliary wheel operably paired with the gear, and for issuing a corresponding signal;

[0017] An electronic control unit is operably connected to the at least one proximity sensor and is configured to receive and process a signal from the at least one proximity sensor, and to control a control mechanism of the circular weft knitting machine and / or a functional parameter of the circular weft knitting machine according to the signal.

[0018] In a second aspect, the present invention relates to a control method for a circular weft knitting machine, comprising:

[0019] Acquiring a signal from at least one proximity sensor for detecting the passage of teeth of a gear of a needle holding mechanism of a circular weft knitting machine and / or the passage of teeth of at least one auxiliary wheel operatively paired with the gear, wherein the needle holding mechanism rotates about its own central axis and the gear is coaxial with the central axis;

[0020] The mechanism of the circular weft knitting machine and / or the functional parameters of the circular weft knitting machine are controlled according to the signal.

[0021] In one aspect, the electronic control unit is configured to calculate the relative position and speed of the needle holding mechanism around the central axis from the signal.

[0022] In one aspect, the method of the preceding aspect or one or more of the following aspects is performed by a knitting machine of the preceding aspect or one or more of the following aspects, and vice versa, the knitting machine of the preceding aspect or one or more of the following aspects is configured to perform the method of the preceding aspect or one or more of the following aspects.

[0023] The Applicant has verified that the knitting machine and / or the method according to the invention ensures a precise and reliable detection of the speed and / or angular position of the needle holding mechanism about its own central axis. In fact, if the proximity sensor is mounted to detect the passage of the teeth of a gear wheel (which is a single element together with the needle holding mechanism or integral with the needle holding mechanism), the electronic control unit directly reads the movement of the needle holding mechanism. On the other hand, if the proximity sensor is mounted to detect the teeth of an auxiliary wheel, the reading is accurate in any case, since the auxiliary wheel is coincident with the gear wheel.

[0024] The applicant has demonstrated that this detection accuracy and reliability enables the electronic control unit to accurately and reliably control the various mechanisms and operating parameters of the machine.

[0025] The Applicant has also demonstrated that the knitting machine and / or the method according to the invention can maintain this accuracy and reliability over a long period of time.

[0026] The Applicant has also demonstrated that the knitting machine and / or the method according to the invention can produce high quality fabrics and provide the properties that were intended to be achieved.

[0027] Applicants have also demonstrated that the detection system according to the invention is economical, robust and minimally invasive.

[0028] Other aspects of the invention are listed below.

[0029] In one aspect, the knitting machine comprises the at least one auxiliary wheel operatively paired with the gear.

[0030] In one aspect, at least one proximity sensor includes a first proximity sensor and a second proximity sensor mounted on a base; wherein the first proximity sensor emits a corresponding first signal and the second proximity sensor emits a corresponding second signal; wherein the electronic control unit is configured to control a mechanism of a circular weft knitting machine and / or functional parameters of the circular weft knitting machine according to the first signal and the second signal.

[0031] In one aspect, the first proximity sensor and the second proximity sensor are mounted at different locations on the base.

[0032] In one aspect, the electronic control unit is configured to receive and process the first signal and the second signal, and to determine the rotation direction of the needle holding mechanism around the central axis.

[0033] The above structure provides two phase-shifted waveforms (first signal and second signal) to the electronic control unit. By reading only one signal (for example, the first signal), information related to the rotation speed can be obtained, and by acquiring the other signal (the second signal), the rotation direction can be determined based on the state sequence generated by the two signals.

[0034] In one aspect, the at least one auxiliary wheel includes a first auxiliary wheel and a second auxiliary wheel; wherein the first proximity sensor is mounted to detect the passage of teeth of the first auxiliary wheel and the second proximity sensor is mounted to detect the passage of teeth of the second auxiliary wheel.

[0035] In one aspect, at least one auxiliary wheel is directly driven with the gear, or the at least one auxiliary wheel is paired with the gear through an intermediate gear.

[0036] In one aspect, there is no flexible transmission between the gear and the at least one auxiliary wheel.

[0037] In one aspect, the at least one auxiliary wheel is an auxiliary wheel mechanically connected to the main motor and transmits the movement of the main motor to the gear.

[0038] In one aspect, the at least one auxiliary wheel is an auxiliary wheel coupled to a crank via a clutch for manually rotating the needle holding mechanism, such as for maintenance operations.

[0039] In one aspect, the auxiliary proximity sensor is operably connected to the electronic control unit.

[0040] In one aspect, the auxiliary proximity sensor is fixedly mounted relative to the base.

[0041] In one aspect, the auxiliary proximity sensor is received in a hole in the base.

[0042] In one aspect, the auxiliary proximity sensor is configured to detect the passage of a single element integral to the needle holder and to generate a corresponding auxiliary signal.

[0043] In one aspect, the electronic control unit is configured to receive and process the auxiliary signal and determine the absolute angular position of the needle holding mechanism around the central axis. The auxiliary signal provides an absolute zero position of the needle holding mechanism.

[0044] In one aspect, the individual elements are spikes, grooves or teeth.

[0045] In one aspect, the teeth of the gear wheel and / or the at least one auxiliary wheel each have a head portion which is located on a head circumference.

[0046] In one aspect, the teeth have respective widths measured along the circumference of the head, and the spaces between consecutive teeth have respective widths measured along the circumference of the head.

[0047] In one aspect, the signal of the at least one proximity sensor is defined by a respective square wave.

[0048] In one aspect, the ratio between the tooth width and the width of the gap is such that the width of the square wave peaks is equal to or substantially equal to the width of the square wave valleys.

[0049] In one aspect, the first signal and the second signal are defined by respective square waves.

[0050] In one aspect, the ratio between the tooth width and the width of the gap is such that the width of each square wave peak is equal to or substantially equal to the width of the square wave trough itself.

[0051] In one aspect, the ratio between the width of the teeth and the width of the gap can compensate for the characteristics of the at least one proximity sensor so that the width of the square wave peaks is equal to or substantially equal to the width of the square wave valleys.

[0052] In one aspect, the characteristic includes a nominal detection distance and / or hysteresis of the proximity sensor.

[0053] In one aspect, the ratio between the width of the teeth and the width of the gap measured along the circumference of the head is between 0.60 and 0.99, optionally between 0.70 and 0.99, optionally between 0.85 and 0.95.

[0054] In one aspect, the teeth of the gear wheel and / or of the at least one auxiliary wheel have an involute profile.

[0055] In one aspect, the gear and / or the at least one auxiliary wheel has a pitch circumference with a pitch diameter and an outer circumference with an outer diameter, wherein the head circumference of the teeth is located between the pitch circumference and the outer circumference.

[0056] In one aspect, the tooth width measured along the circumference of the head is greater than the tooth width measured along the outer circumference and less than the tooth width measured along the circumference of the pitch circle.

[0057] In one aspect, the at least one proximity sensor faces a portion of the gear wheel and / or the at least one auxiliary wheel.

[0058] In one aspect, the at least one proximity sensor is received in a hole in the base.

[0059] In one aspect, the teeth present corresponding heads on the head circumference at the above-mentioned portion, and the teeth themselves present corresponding heads on the outer circumference at the rest of the gear and / or at least one auxiliary wheel.

[0060] In one aspect, the teeth of the portion of the gear and / or the at least one auxiliary wheel have a height lower than the height of the teeth of the remaining portion of the gear and / or the at least one auxiliary wheel.

[0061] In one aspect, the teeth of the gear wheel and / or the at least one auxiliary wheel have edges which are parallel to the respective rotational axes of the gear wheel and / or the at least one auxiliary wheel.

[0062] In one aspect, the edge is a sharp edge.

[0063] In one aspect, the proximity sensor is magnetic, and may also be Hall effect, inductive or capacitive, or laser.

[0064] In one aspect, the gear rotates integrally with the needle.

[0065] In one aspect, the gear is located on a radially outer surface of the needle holding mechanism.

[0066] In one aspect, the gear wheel and / or the at least one auxiliary wheel are made of a magnetic or magnetizable material, such as cast iron, steel, iron.

[0067] In one aspect, a magnetic filter operates adjacent the gear and / or at least one auxiliary wheel to remove any metal shavings.

[0068] In one aspect, a magnetic filter operates in proximity to the at least one proximity sensor.

[0069] In one aspect, the knitting machine includes a stretching device mounted on a base below the knitting assembly and driven by respective actuators controlled by an electronic control unit, wherein the stretching device is configured to maintain tension on the formed fabric.

[0070] In one aspect, the cutter is mounted on a base and driven by a corresponding actuator controlled by an electronic control unit, wherein the cutter is configured to cut the formed fabric.

[0071] In one aspect, a collector (preferably a winder) is mounted on a base below the weaving assembly and driven by a corresponding motor controlled by an electronic control unit, wherein the collector is used to collect (preferably wind) the forming fabric.

[0072] In one aspect, a blower is mounted on the weaving assembly and / or a yarn guide above the weaving assembly and is driven by at least one actuator controlled by an electronic control unit, wherein the blower is configured to blow air to cool and remove dust residues on the bed surface.

[0073] In one aspect, the blower includes at least one fan driven by the at least one actuator and / or a nozzle connected to a source of compressed air.

[0074] In one aspect, the blower is mounted on a rotating support that is driven to rotate by a motor.

[0075] In one aspect, the electronic control unit is configured to manage anomalies of the at least one signal, optionally the first signal and the second signal, and issue an alarm signal and / or shut down.

[0076] In one aspect, the electronic control unit is configured to control and direct the main motor and / or the traction device and / or the cutter and / or the collector and / or the blower according to the signal.

[0077] In one aspect, the action device includes an action triangle.

[0078] In one aspect, the actuation means is disposed around the needle holding cylinder.

[0079] In one aspect, the method includes positioning the at least one proximity sensor to detect the passage of teeth of a gear of the needle holding mechanism and / or the passage of teeth of the at least one auxiliary wheel.

[0080] In one aspect, the method includes rotating the needle holding mechanism and the gear about their own central axis via a main motor paired with the gear.

[0081] In one aspect, the method includes calculating the relative position and velocity of the needle holding mechanism around the central axis using the signal.

[0082] In one aspect, acquiring a signal includes acquiring a first signal sent by a first proximity sensor and acquiring a second signal sent by a second proximity sensor.

[0083] In one aspect, the controlling comprises: controlling a mechanism of the circular weft knitting machine and / or a functional parameter of the circular weft knitting machine according to the first signal and the second signal.

[0084] In one aspect, the at least one signal is defined by a square wave.

[0085] In one aspect, the first signal and the second signal are each defined by a square wave.

[0086] In one aspect, the width of each square wave peak is equal to or substantially equal to the width of the trough of the square wave itself.

[0087] In one aspect, the method includes positioning a first proximity sensor and a second proximity sensor such that a first signal and a second signal are offset from each other.

[0088] In one aspect, the method includes positioning the first proximity sensor and the second proximity sensor in such a way that the first signal peaks and the second signal peaks always partially overlap.

[0089] In one aspect, the method comprises arranging the teeth of the gear and / or the teeth of the at least one auxiliary wheel in such a way that the width of the peaks of the square wave is equal or substantially equal to the width of the troughs of the square wave.

[0090] In one aspect, the method includes arranging teeth of the gear and / or teeth of the at least one auxiliary wheel in a manner to compensate for characteristics of the at least one proximity sensor so that a width of a square wave peak is equal to or substantially equal to a width of a square wave trough.

[0091] In one aspect, the characteristic includes a nominal detection distance and / or hysteresis of the proximity sensor.

[0092] In one aspect, the method includes: determining the rotation direction of the needle holding mechanism around the central axis by using the first signal and the second signal.

[0093] In one aspect, the method includes acquiring an auxiliary signal from an auxiliary proximity sensor positioned to detect passage of a single element integral to the needle holding mechanism.

[0094] In one aspect, the method includes: determining the absolute angular position of the needle holding mechanism around the central axis by using the first signal, the second signal and the auxiliary signal.

[0095] In one aspect, controlling the mechanism and / or functional parameters of the circular weft knitting machine includes: controlling and guiding the main motor and / or the drafting device and / or the cutter and / or the collector and / or the blowing device according to the signal.

[0096] According to the present invention, more features and advantages will be better revealed by the detailed description of preferred but non-limiting embodiments of a circular weft knitting machine and a control method for a circular weft knitting machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0097] The present description will be described with reference to the accompanying drawings, which are for illustrative purposes only and are not limiting, in which:

[0098] - Figure 1 An overall three-dimensional view of the circular weft knitting machine of the present invention is shown;

[0099] - Figure 2 Shows Figure 1 a knitting machine in which some parts are not shown to better highlight other parts;

[0100] - Figure 3 Shows Figure 1 and Figure 2 A two-plane cross-sectional view of a portion of a knitting machine shown in;

[0101] - Figure 4 A three-dimensional view of the knitting machine assembly shown above is shown;

[0102] - Figure 5 Shows Figure 4 A magnified view of the components in the figure;

[0103] - Figure 6 Shows Figure 4 and Figure 5 an enlarged view of the components shown in;

[0104] - Figure 7 Shows Figure 4 , Figure 5 and Figure 6 A partial schematic diagram of the gear in FIG.

[0105] - Figure 8 shows the signal associated with the proximity sensor Figure 7 The development of the gear shown in;- Fig. 9 The signals generated by two proximity sensors are shown;

[0106] - Fig.10 , 11 12 and 13 show the abnormal signals of the two proximity sensors.

[0107] Description of reference numerals:

[0108] 1: Circular weft knitting machine

[0109] 2: Base

[0110] 3: Braided components

[0111] 4: Needle holding mechanism

[0112] XX: Center axis

[0113] YY: Rotation axis

[0114] 5: Upper support ring or component

[0115] 6: Base

[0116] 7: Action Device

[0117] 8: Gear

[0118] T: Tubular fabric

[0119] 9: Main motor

[0120] 10: First belt

[0121] 11: First pulley

[0122] 12: Second belt

[0123] 13: The third pulley

[0124] 14: Training wheels

[0125] 15A, 15B, 15C: Training wheels installed in freewheeling mode

[0126] 16: Crank

[0127] 17A: First proximity sensor

[0128] 17B: Second proximity sensor

[0129] 18, 18': teeth

[0130] 19: Electronic control device

[0131] 20: Auxiliary proximity sensor

[0132] 21: Single component

[0133] 22: Traction and / or collection group

[0134] 23: Spreading roller

[0135] 24: Fan

[0136] 100: Shell frame

[0137] ct: head circumference

[0138] cp: pitch circle circumference

[0139] ce: outer circumference

[0140] dt: head diameter

[0141] dp: pitch diameter

[0142] de: outer diameter

[0143] Lt: Tooth width measured along the head circumference "ct"

[0144] Lp: Tooth width measured along the pitch circle circumference "cp"

[0145] Le: Tooth width measured along the outer circumference "ce"

[0146] Lv: Width of the gap measured along the circumference of the head "ct"

[0147] Ac: peak width

[0148] Ag: valley width

[0149] S1: First signal

[0150] S2: Second signal

[0151] S3: Auxiliary signal

[0152] Fs: Leading edge

[0153] Fd: trailing edge DETAILED DESCRIPTION

[0154] With reference to the above-mentioned drawings, a circular weft knitting machine according to the present invention is generally indicated by numeral 1 .

[0155] The circular weft knitting machine 1 comprises a base 2, which constitutes the bearing structure of the knitting machine and can be placed on the ground. A knitting assembly 3 is mounted on the base 2 and is provided with a needle holding mechanism 4, on which a plurality of knitting needles are movably mounted, and a command device is provided for selectively driving the plurality of knitting needles to produce a tubular fabric "T".

[0156] The needle holding mechanism 4 shown in the drawings is a needle holding cylinder. In an embodiment not shown, the needle holding mechanism 4 may include a needle holding plate combined with the needle holding cylinder. The knitting machine 1 may be a single needle bed or a double needle bed. The needle holding mechanism 4 has a central axis "XX" and a plurality of grooves arranged around the central axis "XX", and a plurality of needles are mounted in the plurality of grooves. The grooves and needles of the needle holding mechanism 4 are not shown because they may be of conventional type and are also known in the technical reference field.

[0157] The base 2 comprises an upper support ring or part 5 on which the knitting assembly 3 is mounted so that the needle holding mechanism 4 can rotate about a central axis "XX". When the knitting machine 1 is properly placed on the ground, the vertical axis "XX" is substantially vertical. The base 2 comprises a base 6 for placement on the ground. In the figures, the base 6 comprises three legs.

[0158] The action device ( Figure 7 ) is used to determine or allow the knitting needle to move along the groove so as to form a knitted fabric by the knitting needle. In the illustrated embodiment, the action device comprises an action triangle fixedly mounted on the base 2. Since the action triangle can be of a known type, it is not described in detail.

[0159] The needle holding mechanism 4 is supported by the support ring 5 via a bearing and has a gear 8 coaxial with the central axis "XX" and having a plurality of teeth. The gear 8 in the example shown is radially outward relative to the needle holding cylinder and is mounted in a circular seat in the support ring 5 together with the bearing. Figure 4 , Figure 5 and Figure 6 The gear 8 can be seen more clearly in the figure. The gear 8 rotates integrally with the needle holding mechanism 4 and the needle.

[0160] The main motor 9 is operatively connected to the gear 8 of the needle holding mechanism 4 and is used to determine the rotation of the needle holding mechanism 4 around the central axis "XX" and relative to the base 2 and the action triangle. Figure 4 It can be seen that the main motor 9 is mounted in one of the legs of the base 6 and is connected to the gear 8 by a flexible transmission device, which is used to transmit the movement of the main motor to the gear. In particular, the flexible transmission device includes a first belt 10 wound on the shaft of the main motor 9 and on a first pulley 11. A second belt 12 is wound on a second pulley coaxial with and integral with the first pulley 11, and a third pulley 13 coaxial with and integral with an auxiliary wheel 14 meshing with the gear 8 ( Figure 4 and Figure 5 The first pulley 11 and the second pulley are rotatably mounted on the base 2. The third pulley 13 and the auxiliary wheel 14 are also rotatably mounted on the base 2.

[0161] As can be seen, the knitting machine 1 comprises auxiliary wheels 15A, 15B, 15C, which are mounted in idle mode on the base 2 and mesh with the gear 8. For example, the gear 8, the auxiliary wheel 14 and the auxiliary wheels 15A, 15B, 15C have an involute profile. The auxiliary wheels 15 are arranged at different angular positions around the central axis "XX". Each auxiliary wheel 15A, 15B, 15C mounted in idle mode is also paired with a crank 16 via a clutch. The crank 16 is used to manually rotate the needle holding mechanism 4 when the knitting machine 1 is stopped, for example to perform maintenance operations.

[0162] The first auxiliary wheel 15A installed in the idle mode and the second auxiliary wheel 15B installed in the idle mode are paired with the first proximity sensor 17A and the second proximity sensor 17B installed on the base 2, respectively. The first proximity sensor 17A and the second proximity sensor 17B are respectively installed in the through holes on the radial outer wall of the support ring 5, and one end of each proximity sensor 17A and 17B faces the teeth of the first auxiliary wheel 15A and the second auxiliary wheel 15B, respectively. The first proximity sensor 17A and the second proximity sensor 17B are fixedly installed on the base 2. When the knitting machine 1 is running and the needle holding cylinder rotates, the first auxiliary wheel 15A and the second auxiliary wheel 15B are dragged to rotate, and the teeth of the first auxiliary wheel 15A and the second auxiliary wheel 15B slide in front of the first proximity sensor 17A and the second proximity sensor 17B, respectively. The first proximity sensor 17A is installed to detect whether the teeth 18 of the first auxiliary wheel 15A pass through, and the second proximity sensor 17B is installed to detect whether the teeth 18 of the second auxiliary wheel 15B pass through.

[0163] In the illustrated embodiment, the first and second proximity sensors 17A and 17B are cylinders oriented in a radial direction relative to the respective rotational axes "YY" of the first and second auxiliary wheels 15A and 15B.

[0164] The first auxiliary wheel 15A and the second auxiliary wheel 15B are substantially the same, and the first proximity sensor 17A and the second proximity sensor 17B are also substantially the same, so only reference will be made to the first auxiliary wheel 15A and the second auxiliary wheel 15B in the following text. Figure 5 , Figure 6 , Figure 7 and Figure 8 The structure and function of an assembly consisting of the first auxiliary wheel 15A and the first proximity sensor 17A will be described.

[0165] The first proximity sensor 17A is of the Hall effect magnetic type, the working principle of which is known per se and therefore not described in detail here. The first auxiliary wheel 17A comprises a plurality of upright teeth 18, i.e. the teeth 18 are arranged parallel to the respective rotation axis "YY". The teeth 18 of the first auxiliary wheel 17A are made of a material capable of interacting with the Hall effect first proximity sensor 17A, i.e. by means of a magnetic or magnetized material, such as cast iron, steel, iron.

[0166] In order to optimize the function of the Hall effect first proximity sensor 17A, an operable magnetic filter may further be mounted on the first auxiliary wheel 15A so that any metal shavings generated by the interaction between the gear 8 and the first auxiliary wheel 15A are removed and away from the first proximity sensor 17A.

[0167] In other embodiments, the proximity sensor may be of a different type, such as an inductive or capacitive laser sensor.

[0168] The first auxiliary wheel 17A has a pitch circle circumference "cp" with a pitch circle diameter "dp" and an outer circumference "ce" with an outer diameter "de". As is well known, the pitch circle diameter "dp" of a gear refers to the diameter of the circumference (pitch circle circumference "cp") passing through the circumference where the tooth width is equal to the gap width. The outer circle of the tooth top determines the outer diameter "de".

[0169] Figure 6 It can be clearly seen that the first auxiliary wheel 17A has a unique portion, the height of the teeth 18 of which is lower than the height of the teeth 18 of the remaining portion of the first auxiliary wheel 17A, that is, relative to the engineering drawing, the shape and size of the teeth 18 meet the correct transmission performance, and the height of the teeth 18 is lower. In this portion, the head circumference "ct" of the teeth 18 is not consistent with the outer circumference "ce", but is located between the pitch circle circumference "cp" and the outer circumference "ce" ( Figure 7 ). The head diameter "dt" (or discharge diameter) of the head circumference "ct" is smaller than the outer diameter "de" and larger than the pitch diameter "dp" ( Figure 7 ). Therefore, the width "Lt" of the tooth 18 measured along the head circumference "ct" is greater than the width "Le" of the tooth 18 measured along the outer circumference "ce", and less than the width "Lp" of the tooth 18 measured along the pitch circle circumference "cp" ( Figure 8 ). In addition, the width "Lt" of the tooth 18 measured along the head circumference "ct" is greater than the width "Lv" of the gap measured along the head circumference "ct". In addition, the tooth 18 of the first auxiliary wheel 15A has a sharp edge.

[0170] The first proximity sensor 17A detects the presence of the tooth 18 within its nominal range and switches between two states by emitting a square wave first signal "S1": a square wave peak is emitted when a tooth passes, and a square wave trough is emitted when a gap passes ( Figure 8 ).

[0171] When calculating the ratio between the width "Lt" of the tooth 18 measured along the head circumference "ct" and the width "Lv" of the gap measured along the head circumference "ct" (and processing / releasing the teeth of this part accordingly), the following factors need to be taken into account at the same time: the characteristics of the first proximity sensor 17A (nominal detection distance and / or hysteresis), so that the square wave peak width "Ac" of the first signal "S1" is equal to or substantially equal to the square wave valley width "Ag" (Ac=Ag, Figure 8)。Normally, the ratio of "Lt / Lv" is less than 1, for example, between 0.60 and 0.99, preferably between 0.85 and 0.95. In other words, by having the first proximity sensor 17A read the teeth 18 on the head circumference "ct" (where Lt < Lg), an electronic equivalent value (Ac = Ag) of the pitch circle circumference "cp" can be obtained. On the other hand, if the teeth 18 are displaced to the pitch circle circumference "cp", the width "Ac" of the square wave peak will be greater than the width "Ag" of the trough, and one peak of the first signal "S1" will overlap with two adjacent peaks of the second signal "S2". In this case, in order to ensure that the leading edges "Fs" and trailing edges "Fd" of the signals "S1" and "S2" follow each other at a predetermined rhythm, precise mechanical machining procedures and / or electronic adjustments must be performed on each knitting machine.

[0172] The above situation also applies to the assembly consisting of the second auxiliary wheel 15B and the second proximity sensor 17B. Fig. 9 The first signal "S1" emitted by the first proximity sensor 17A and the second signal "S2" emitted by the second proximity sensor 17B are shown. It can be seen that both the first signal "S1" and the second signal "S2" are defined by respective square waves and are offset from each other, so that the peak portions overlap. The first proximity sensor 17A and the second proximity sensor 17B can be appropriately positioned relative to the teeth 18 of the first auxiliary wheel 15A and the second auxiliary wheel 15B respectively, so that the first signal "S1" and the second signal "S2" are offset from each other. As shown in the figure, if the width "Ac" of the square wave peak of the two signals is equal to the width "Ag" of the square wave trough, precise positioning of the first proximity sensor 17A and the second proximity sensor 17B is not required, because the phase shift and peak overlap of the two signals "S1" and "S2" are both minimal.

[0173] The knitting machine 1 includes an electronic control unit 19 and is controlled thereby, as Figure 6 shown. The electronic control unit 19 is operably connected to the first proximity sensor 17A and the second proximity sensor 17B for receiving and processing the first signal "S1" and the second signal "S2", and for controlling the mechanism of the knitting machine 1 and / or the functional parameters of the knitting machine 1 according to the signals "S1" and "S2". By reading one of the two signals (for example, the first signal "S1"), the electronic control unit 19 calculates the rotational speed of the needle cylinder, and by acquiring the other signal (the second signal "S1"), the electronic control unit 19 discriminates the rotational direction based on the state sequence generated by the two signals "S1" and "S2".

[0174] In addition, the knitting machine 1 also includes an auxiliary proximity sensor 20 integrated with the base 2, which is used to detect the passage of a single element 21 (such as a hook) integrated with the needle holding mechanism 4 and send a corresponding auxiliary signal "S3". Figure 3 The individual elements 21 may be in other shapes, such as grooves or teeth, instead of hooks.

[0175] In addition, the auxiliary proximity sensor 20 is connected to the electronic control unit 19. The electronic control unit 19 is configured to receive and process the auxiliary signal "S3" and determine the absolute angular position of the needle holding mechanism 4 around the central axis "XX". The auxiliary signal "S3" is a squared pulse ( Fig. 9 ), every time it rotates 360°, the electronic control unit 19 will receive the signal and provide the absolute zero position of the needle holding mechanism 4.

[0176] The knitting machine 1 includes a known traction device mounted on the base 2 below the knitting assembly 3 for maintaining the tension ( Figure 2 and Figure 3 The knitting machine 1 also includes a take-up mechanism mounted on the base 2 below the knitting assembly 3 for collecting (preferably winding) the formed fabric "T".

[0177] The knitting machine 1 may also comprise a cutter, not shown in the figures, for example of a known type, for cutting and opening the shaped fabric "T".

[0178] The drafting device is driven by various actuators controlled by the electronic control unit 19. The winding mechanism is driven by a motor controlled by the electronic control unit 19. The cutter is driven by various actuators controlled by the electronic control unit 19.

[0179] In the illustrated knitting machine 1, the traction device and the take-up mechanism are integrated in a traction and / or collection group 22, which is movably mounted in the collection space between the legs of the base 6 and is closed by a carter 100 ( Figure 1 and 2 The pulling and / or collecting group 22 is used to open and unfold, and possibly even to stretch the fabric "T" produced by the weaving assembly 3, and to wind it continuously in a single layer on a collecting roll. Figure 2 The collecting roller is not visible in the drawing because it is hidden behind the spreading roller 23. The spreading roller 23 (also called the tensioning roller) is mounted upwardly relative to the collecting roller for interacting with the fabric "T" advancing toward the collecting roller in order to spread it out before winding on the collecting roller.

[0180] The traction and / or collection group 22 shown in the figure is suspended on the needle holding mechanism 4, and is suspended in the collection space in this way and rotates together with the needle holding mechanism 4. The cutter not shown in the figure is part of the traction and / or collection group 22, which is used to cut the forming fabric "T" and cut it into single layers.

[0181] The knitting machine 1 further comprises a blower mounted on the knitting assembly 3 and / or the yarn guide on the upper part of the knitting assembly 3. The function of the blower is to blow air to cool and remove residual dust on the bed surface. The blower is driven by an actuator or actuators controlled by an electronic control unit 19. The blower is mounted on a bracket driven to rotate by a motor. In the illustrated knitting machine 1, the blower comprises a fan 24 and a nozzle (not shown in the drawings) connected to a compressed air source.

[0182] According to the circular weft knitting machine control method of the present invention, the electronic control unit 19 can control and guide the main motor 9 and / or the drafting device and / or the cutter and / or the collector and / or the blower, and control the operating parameters of the knitting machine 1 according to the first signal "S1", the second signal "S2" and the auxiliary signal "S3", or the relative and absolute angular position, rotation direction and rotation speed of the needle holding mechanism 4.

[0183] Furthermore, the electronic control unit 19 can also manage abnormalities of the first signal "S1" and the second signal "S2" and issue an alarm signal and / or stop the knitting machine 1. For example, in the event of a signal loss, such as Fig.10 As shown, this means that there is a problem with the proximity sensor's electrical connections and / or the proximity sensor itself. Fig.11 A situation is shown where the second proximity sensor 17B is faulty or disconnected. Fig.12 A further check that the control unit 19 can perform is to count the number of teeth detected by the first sensor 17A and / or the second sensor 17B during a 360° rotation of the needle holding mechanism 4 and to check whether this number of teeth is correct using the auxiliary signal "S3", which gives an indication of a rotational shutdown.

[0184] In other embodiments not shown, the first proximity sensor 17A and the second proximity sensor 17B may be positioned to read the teeth 18' of the gear 8. In this case, a portion of the gear 8 may present teeth 18' of a lower height, as shown in the first auxiliary wheel 15A in the above figure. In a further embodiment, the first proximity sensor 17A may be positioned to read the teeth 18' of the gear 8, while the second proximity sensor 17B reads the teeth 18 of the respective second auxiliary wheel 17B. In a further embodiment, the first proximity sensor 17A and the second proximity sensor 17B may be positioned to read the teeth 18 of the auxiliary wheel itself, which may also be the auxiliary wheel 14 of the above-mentioned flexible transmission. In other embodiments not shown, a single auxiliary wheel or auxiliary wheels 15A, 15B in combination with proximity sensors 17A, 17B are not directly engaged with the gear 8, but are paired with the gear 8 through respective intermediate gears.

[0185] In different embodiments, the peak width "Ac" and the trough width "Ag" of the first signal "S1" and / or the second signal "S2" may also be different from each other. In this case, the first proximity sensor 17A and the second proximity sensor 17B must be positioned in such a way that the overlap between the two signals can identify the rotation direction of the needle holding mechanism 4.

[0186] In further embodiments not shown and within the scope of the invention, the knitting machine 1 is not equipped with the auxiliary proximity sensor 20 and the electronic control unit 19 to calculate the rotation speed, rotation direction and relative angular position of the needle holding mechanism 4 but not the absolute angular position.

[0187] In a further embodiment not shown, the knitting machine 1 comprises a unique proximity sensor 17A which allows the electronic control unit 19 to calculate the rotation speed and the relative angular position of the needle holding mechanism 4, but not the rotation direction and the absolute angular position.

[0188] The present invention has significant advantages.

[0189] The present invention can detect the position and / or speed and / or rotation direction of the needle holding mechanism in real time and accurately without generating errors due to factors such as the encoder reading on the main motor and the deformation / elasticity of the transmission device between the main motor and the needle holding mechanism.

[0190] The invention can effectively control the knitting machine, in particular, can control the various mechanisms of the knitting machine, and accurately and reliably control its operating parameters. The electronic control device knows the position of the cylinder in real time, can calculate the production volume and production speed of the fabric, and then cut, pull, collect the required amount at the required time and quantity, and move the fan for effective cooling and dust removal.

[0191] The present invention can safely stop the knitting machine according to the proximity sensor signal.

[0192] The invention can optimize the operation of the knitting machine, thereby saving energy.

[0193] In addition, the control system adopted is simple, reliable and economical.

Claims

1. A circular weft knitting machine, comprising: A base (2) that can be placed on the ground; A knitting assembly (3) mounted on a base (2), the knitting assembly (3) comprising: a needle holding mechanism (4) having a central axis (XX) and a plurality of grooves arranged around the central axis (XX), wherein a plurality of knitting needles are accommodated in the plurality of grooves; an action device (7) fixedly mounted on the base (2), which is operably paired with or suitable for pairing with the knitting needles and can determine or allow the knitting needles to move along the grooves so as to form a knitted fabric through the knitting needles; the needle holding mechanism (4) comprises a gear (8) coaxial with the central axis (XX) and having a plurality of teeth (18'); a main motor (9), operably connected to the gear (8) of the needle holding mechanism (4), for determining the rotation of the needle holding mechanism (4) around the central axis (XX) and relative to the base (2); at least one proximity sensor (17A, 17B) fixedly mounted relative to the base (2), for detecting the passage of a tooth (18') of the gear (8) and / or the passage of a tooth (18) of at least one auxiliary wheel (15A, 15B) operably paired with the gear (8), and for sending a corresponding signal (S1, S2); An electronic control unit (19) is operably connected to the at least one proximity sensor (17A, 17B) and is configured to receive and process signals (S1, S2) from the at least one proximity sensor (17A, 17B), and to control a control mechanism of the circular weft knitting machine (1) and / or functional parameters of the circular weft knitting machine (1) according to the signals (S1, S2).

2. The circular weft knitting machine according to claim 1, characterized in that: The at least one proximity sensor (17A, 17B) comprises a first proximity sensor (17A) and a second proximity sensor (17B) mounted on the base (2), wherein the first proximity sensor (17A) sends a corresponding first signal (S1), and the second proximity sensor (17B) sends a corresponding second signal (S2); wherein the electronic control unit (19) is configured to control the mechanism of the circular weft knitting machine (1) and / or the functional parameters of the circular weft knitting machine (1) according to the first signal (S1) and the second signal (S2).

3. The circular weft knitting machine according to claim 2, characterized in that: The electronic control unit (19) is configured to calculate the relative position and speed of the needle holding mechanism (4) around the central axis (XX) through the signals (S1, S2), wherein the electronic control unit (19) is configured to receive and process the first signal (S1) and the second signal (S2), and determine the rotation direction of the needle holding mechanism (4) around the central axis (XX).

4. The circular weft knitting machine according to claim 2 or 3, characterized in that: The at least one auxiliary wheel (15A, 15B) comprises a first auxiliary wheel (15A) and a second auxiliary wheel (15B), wherein the first proximity sensor (17A) is installed to detect the passage of teeth (18) of the first auxiliary wheel (15A), and the second proximity sensor (17B) is installed to detect the passage of teeth (18) of the second auxiliary wheel (15B).

5. The circular weft knitting machine according to any one of claims 1 to 4, characterized in that It includes an auxiliary proximity sensor (20) operably connected to the electronic control unit (19), the auxiliary proximity sensor (20) is fixedly mounted relative to the base (2), and is configured to detect the passage of a single element (21) integrated with the needle holding mechanism (4) and to send a corresponding auxiliary signal (S3), wherein the electronic control unit (19) is configured to receive and process the auxiliary signal (S3) and to determine the absolute angular position of the needle holding mechanism (4) around the central axis (XX).

6. The circular weft knitting machine according to any one of claims 1 to 5, characterized in that The teeth (18, 18') of the gear (8) and / or the at least one auxiliary wheel (15A, 15B) respectively have heads arranged on a head circumference (Ct); wherein the teeth (18, 18') have respective widths (Lt) measured along the head circumference (Ct); wherein gaps defined between consecutive teeth (18, 18') have respective widths (Lv) measured along the head circumference (Ct); wherein the first signal (S1) and the second signal (S2) are respectively defined by respective square waves; wherein the ratio between the width (Lt) of the teeth (18, 18') and the width (Lv) of the gaps is such that the peak width (Ac) of each square wave is equal to or substantially equal to the trough width (Ag) of the square wave.

7. The circular weft knitting machine according to claim 6, characterized in that The ratio between the width (Lt) of the teeth (18, 18') and the width (Lv) of the gap is between 0.60 and 0.99, optionally between 0.85 and 0.

95.

8. The circular weft knitting machine according to claim 6 or 7, characterized in that: The gear (8) and / or the at least one auxiliary wheel (15A, 15B) have a pitch circle circumference (Cp) with a pitch circle diameter (dp) and an outer circumference (Ce) with an outer diameter (de), wherein the head circumference (Ct) of the tooth (18, 18') is located between the pitch circle circumference (Cp) and the outer circumference (Ce), and the width (Lt) of the tooth (18, 18') measured along the head circumference (Ct) is greater than the width (Le) of the tooth (18, 18') measured along the outer circumference (Ce) and smaller than the width (Lp) of the tooth (18, 18') measured along the pitch circle circumference (Cp).

9. The circular weft knitting machine according to claim 8, characterized in that The at least one proximity sensor (17A, 17B) is facing a portion of the gear (8) and / or the at least one auxiliary wheel (15A, 15B); wherein the tooth (18, 18') has a corresponding head on the head circumference (Ct) at the portion, and the tooth (18, 18') itself has a corresponding head on the outer circumference (Ce) at the rest of the gear (8) and / or the at least one auxiliary wheel (15A, 15B).

10. The circular weft knitting machine according to any one of claims 1 to 10, characterized in that The electronic control unit (19) is configured to control and direct the main motor (9) and / or the traction device and / or the cutter and / or the collector and / or the blower according to the signals (S1, S2).

11. A control method for a circular weft knitting machine, comprising: Acquiring a signal (S1, S2) from at least one proximity sensor (17A, 17B), the proximity sensor being positioned to detect the passage of a tooth (18') of a gear (8) of a needle holding mechanism (4) of a circular weft knitting machine (1) and / or the passage of a tooth (18) of at least one auxiliary wheel (15A, 15B) operably paired with the gear (8), wherein the needle holding mechanism (4) rotates around its own central axis (XX) and the gear (8) is coaxial with the central axis (XX); The mechanism of the circular weft knitting machine (1) and / or the functional parameters of the circular weft knitting machine (1) are controlled according to the signals (S1, S2).

12. The method according to claim 11, characterized in that Acquiring signals (S1, S2) includes: acquiring a first signal (S1) emitted by a first proximity sensor (17A) and acquiring a second signal (S2) emitted by a second proximity sensor (17B).

13. The method according to claim 12, characterized in that include: The first proximity sensor (17A) is positioned and the second proximity sensor (17B) is positioned so that the first signal (S1) and the second signal (S2) are offset from each other and the peaks of the first signal (S1) and the peaks of the second signal (S2) always partially overlap each other.

14. The method according to claim 12 or 13, characterized in that The first signal (S1) and the second signal (S2) are defined by respective square waves; wherein it is provided that the teeth (18') of the gear (8) and / or the teeth (18) of the at least one auxiliary wheel (15A, 15B) are arranged in a manner to compensate for the characteristics of the at least one proximity sensor (17A, 17B) and to make the peak width (Ac) of the square wave equal to or substantially equal to the trough width (Ag) of the square wave.

15. The method according to claim 14, characterized in that The characteristics include a nominal detection distance and / or hysteresis of the proximity sensor (17A, 17B).

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