US3719061A - Safety device for flat knitting machine - Google Patents

Safety device for flat knitting machine Download PDF

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Publication number
US3719061A
US3719061A US00199533A US3719061DA US3719061A US 3719061 A US3719061 A US 3719061A US 00199533 A US00199533 A US 00199533A US 3719061D A US3719061D A US 3719061DA US 3719061 A US3719061 A US 3719061A
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United States
Prior art keywords
carriage
machine
signal
knitting machine
safety device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00199533A
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English (en)
Inventor
W Hadam
J Ploppa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
H Stoll GmbH and Co KG
Original Assignee
H Stoll GmbH and Co KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from DE2056391A external-priority patent/DE2056391C3/de
Priority claimed from DE19712120824 external-priority patent/DE2120824B2/de
Application filed by H Stoll GmbH and Co KG filed Critical H Stoll GmbH and Co KG
Application granted granted Critical
Publication of US3719061A publication Critical patent/US3719061A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04B—KNITTING
    • D04B35/00—Details of, or auxiliary devices incorporated in, knitting machines, not otherwise provided for
    • D04B35/10—Indicating, warning, or safety devices, e.g. stop motions
    • D04B35/18—Indicating, warning, or safety devices, e.g. stop motions responsive to breakage, misplacement, or malfunctioning of knitting instruments
    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04B—KNITTING
    • D04B35/00—Details of, or auxiliary devices incorporated in, knitting machines, not otherwise provided for
    • D04B35/10—Indicating, warning, or safety devices, e.g. stop motions

Definitions

  • a safety device for sensing large disturbances or reaction forces to out off the machine and hence prevent damage thereto.
  • the safety device includes piezoelectric pressure bodies strategically located to convert pressure forces into electrical signals.
  • An electrical circuit senses the electrical signals and, if the signals are of sufiicient magnitude, causes the machine to cut olf.
  • the electrical circuit may include a comparator to compare signals from the piezoelectric body or bodies or a semi-conductor which transmits a current to a relay to cut off the knitting machine drive only when it is triggered by a peak voltage from the piezoelectric body.
  • This invention relates to a safety device for a flat knitting machine designed for use in stopping the machine in the event of overloads or disturbing forces acting at a monitored part of the machine.
  • the safety device consists of a lever or slide which is held loaded by one or two springsdepending on whether the safety device is to be stressed in one or in both directions of travel of the carriagethe loading determining the permissible stress limits.
  • a known safety device has the drawback that to trigger it the lever or slide must undergo a specific displacement against the force of the spring, or the appropriate spring, as the case may be.
  • An object of the present invention is to provide a safety device of the kind set forth which is not only capable of versatile use not limited merely to the monitoring of the machine carriage, but which also responds more rapidly than previous safety devices, and, if desired, can be made so sensitive that the breakage of a single needle or jack butt can :be recorded and trigger stoppage of the machine drive.
  • At least one force-detecting piezoelectric pressure body is coupled to the monitored machine part and connected in an electrical circuit controlling the machine drive.
  • the piezoelectric pressure body hereinafter referred to as a piezobody for short, may be connected to one input of a signal comparator stage, the output signal of which controls the machine drive.
  • the signal comparator stage may be connected to a reference value emitter which gives a reference value signal dependent on an operative condition of the machine, for example on the carriage setting, and the output signal of the signal comparator stage may be proportional to the difference between the actual value signal and the reference value signal.
  • the piezobody may be polarized in the force transmitting direction under a mechanical bias at one force transmission area of the monitored machine part.
  • the incident mechanical force will produce proportional electrical voltages in the piezobodies, and these can be compared in the signal comparator stage with standard electrical reference voltage signals, the machine ibeing stopped when the reference value is exceeded.
  • the safety device according to the invention has the attribute that it will respond partical'ly without any relative displacement of the monitored part relatively either to the body of the machine or to some other datum part. With no such displacement, the rate of response of this safety device is much higher than is the case with known forms of safety devices; this is in addition to the substantially increased sensitivity secured by the continuous adaption of the reference value signal.
  • the piezoelectric force detector can be made small and relatively sensitive so that it can also be used for the supervision of relatively light parts of the flat knitting machine, for example individual carns or even individual parts of a cam.
  • a driving part of the carriage is equipped at each of its two ends, as seen in the direction of stroke of the carriage, with a piezobody serving as a force detector, and these two piezobodies are indirectly ope-rated by screw bolts which are adjustable and fixably mounted in a driving member having arms which enfold the aforesaid driving part of the carriage at two sides and coupled with a driving component such, for instance, as a chain, spindle or the like.
  • At least one piezobody may be clamped as the force detector between a cam part mounted in the cam box and the cam plate or between the cam plate and the carriage, in which event two piezobodies will be used and arranged at each end of the cam part as related to the direction of carriage travel.
  • the piezobody is arranged in a vibration pick-up which is attached to the needle bed in such a way that the direction in which the grip is applied to piezobody coincides with the longitudinal direction of the said bed.
  • the vibration pick-up may advantageously comprise, in combination, a housing which is applied firmly against the needle bed, a mass within the housing, a piezobody which is provided with two electrodes and is gripped between the wall of the housing and one end of the mass, and a compression spring which is arranged between an opposite end of the mass and housing and urges the mass towards the piezobody.
  • the needle beds In the case of a two-bed flat knitting machine the needle beds would each be provided with a piezoelectric vibration pick-up and the two pick-ups would be electrically connected in parallel.
  • FIG. 1 is a diagrammatic partial sectional view through a carriage of a flat knitting machine provided with one form of the improved safety device.
  • FIG. 2 is a partial plan and partial horizontal sectional view of FIG. 1, taken along line 22 of FIG. 1.
  • FIG. 3 is a diagrammatic section view through a cam part mounted in a cam plate of the carriage and showing another embodiment of the invention.
  • FIG. 4 is a schematic drawing of an electrical circuit portion of the safety device which is usable with the embodiment of FIGS. 1 and 2 and/or the embodiment of FIG. 3.
  • FIG. 5 is a partial plan view of a needle bed of a flat knitting machine and showing another embodiment of the invention.
  • FIG. 6 illustrates schematically an electrical circuit for use with the embodiment of FIG. 5.
  • FIG. 7 is a diagrammatic view showing the general position of the three illustrated embodiments of the invention in a knitting machine.
  • a driving element 11 is connected both to a machine carriage 10 (not fully shown) which moves longitudinally relative to a needle bed 10a and also to a U-shaped driving part 12.
  • This driving part is in turn connected to a driving spindle (not shown) and has arms 12a and 12b which project out around the driving element 11.
  • a piezoelectric pressure body (piezobody for short) 13 is located at each of the two opposite sides 11a and 11b of the driving element 11 and is polarized in the direction of travel of the carriage 10.
  • Each of these two bodies 13, which is effective in one of the directions of travel of the carriage, is provided at both sides thereof in the polarization direction, with electrodes 14.
  • Each inner electrode is insulated relatively to the driving element 11 by an insert 15 of sintered ceramic material, and each piezobody 13, together with its inner electrode, is inserted into a recess in this material.
  • each of the two piezobodies 13 is contacted in the vicinity of its outer electrode 14 by a thrust plate 16 which is also made of an electrically-insulating sintered ceramic material.
  • These thrust plates 16 are applied against the piezobodies 13 by screws 17 which are mounted in the arms 12a and 12b of the driving part 12 in such a Way that these bodies are pre-stressed and are fixed, free of play between the driving parts 11 and 12.
  • FIG. 3 diagrammatically illustrates an arrangement of piezobodies 13 at opposed sides of a cam part 20 which is to be monitored as regards the strength of the forces which are active in the directions of the double arrow 21.
  • the two piezobodies 13' are again provided with electrodes and are mounted in a playfree manner between electrical insulating bearings 22 and pressure bodies 23.
  • Each bearing 22 is connected to the relevant end face of the cam part 20 while the corresponding pressure body 23 1s connected to the adjacent wall of a cambox plate 24 or 25.
  • forces acting on the cam part 20 in the direction of the double arrow 21 are manifest as a consequence of deformation of the piezobodies 13' and the resulting signal voltages are conducted to a signal comparator stage for exploitation.
  • FIG. 4 illustrates an electrical circuit usable with the embodiments of FIGS. 1, 2 and/or FIG. 3.
  • a plurality of piezobodies having their electrodes connected in parallel, and indicated by the voltage arrows U to U are transmitted through an input transformer 31 and a diode 32 to the actual value input terminals 33 and 34 of a slgnal comparator stage 30.
  • a transformer instead of employing a transformer use may be made of a threshold value switch which responds when a specific voltage peak is exceeded.
  • the signal comparator stage 30 has two reference value input terminals 35 and 36 to which is applied a reference signal indicated by the voltage U This reference signal is emitted by a reference value transmitter (not shown) into which a reference value'signal corresponding to an assumed or detected tensile force pattern on the carriage (or other appropriate part) is fed during a stroke of the carriage and is transmitted synchronously with the development of the carriage movement.
  • the signal comparator stage 30 delivers to the two output terminals 37 and 38 thereof control signal or fault signal U which is equal or proportional to the difference between the instantaneous value of the actual signal and the reference value signal. If, by reason of a sudden and rapidly increasing mechanical pressure an actual value signal amplitude is produced at one of the two piezobodies connected in parallel, which amplitude exceeds the reference value signal at that moment applied to the comparator stage 30, an appropriately strong control signal U is produced to stop the flat knitting machine.
  • FIGS. and 6 show a further example of the improved safety device.
  • FIG. 5 illustrates the end section of a needle bed 101.
  • the needle tricks formed in this bed are indicated at 102 and the intervening ribs at 103.
  • a needle 104 is shown inserted in one of the tricks 102, and the butt of this needle is shown at -5.
  • a piezoelectric vibration pickup 106 is arranged at an end of the needle bed 101 .
  • the piezobody 109 has two electrodes .110.
  • the loading of piezobody 109 is performed by a compression spring 111 which is stressed between the other end of mass 108 and the opposing wall of housing 107. Mass 108 is therefore out of direct communication with the housing 107 of the vibration picku 106.
  • the electrodes 110 of piezobody 109 are connected to the two ends of a potentiometer 112 acting as a voltage distributor and a tapping 1.13 of which leads to the control input of a thyristor semiconductor 115 via a protective resistance 1'14.
  • a condenser -116 is coupled bet-ween the control input of thyristor 115 and electrode 110 of the piezobody 109 and this shields the control input of the thyristor from disturbing voltage peaks.
  • the thyristor 11 5 is connected to a control voltage source iU in series with the energizing winding of a relay 117. The relay winding is by-passed in one direction by a diode 118.
  • Relay 1*17 operates a switch 119 in the current supply circuit (not shown) of the fiat knitting machine.
  • the anti-needle breakage system only requires a small outlay in terms of manufacture and electrical equipment and operates in the required way very rapidly and positively.
  • FIG. 7 is a diagrammatic view of an overall needle bed carriage and drive therefor showing the relative locations of the three embodiments of the safety device described in detail above. While only a single cam part 20 is shown in FIG. 7, of course a suitable safety device may be provided for each cam part. Also, in a two-bed knitting machine, these safety devices could be duplicated on the opposite bed and carriage. It will be apparent that any one or any combination of these safety devices may be employed on a single knitting machine.
  • a safety means for stopping the machine in response to forces above a predetermined level acting on a monitored part of the machine, said safety means comprising at least one force-detecting piezoelectric pressure body operatively coupled to said monitored part such that in response to the application of a force from the monitored part to the piezoelectric body a first electrical signal is transmitted, and means responsive to said first electrical signal for controlling the drive of the knitting machine.
  • the invention of claim 1 including a signal comparator, means for developing a reference electrical signal, said comparator including means for receiving and comparing the reference signal and the said first signal and transmitting an output signal proportional to the difference between the said first signal and the said output signal for controlling the drive of the knitting machine.
  • the said comparator has a pair of input means and an output means, said piezoelectric body being connected to one of said input means, means for emitting a reference electrical signal, said reference electrical signal being connected to the second input means of the comparator, and said comparator transmitting an output signal through said output means, which output signal is proportional to the difference between the said first electrical signal and the said reference electrical signal.
  • the invention of claim 5, including a driving member movable with the drive of the knitting machine, said monitored part of the machine being a driven part of the carriage, a force detecting piezoelectric body located on each end of the said driven part of the carriage, as seen in the direction of travel of the carriage, and said driving member having arms positioned on opposite sides of each piezoelectric body, as seen in the direction of travel of the carriage, whereby forces tending to create relative movement between the driving member and the driven parts are sensed by the piezoelectric bodies.
  • the invention of claim 6 including electrically insulated members located on the driven part and said piezoelectric bodies being fixed thereagainst, electrically insulated pressure plates located on the sides of each piezoelectric body opposite from its electrically insulated rnembers, said driving member having an elongated part, out from which the two said arms of the driving member project on opposite sides of the said carriage driven part, and means attached to said arms for adjustably forcing the pressure plates against the said piezoelectric bodies.
  • said comparator receiving a signal from said piezoelectric bodies at the first input and the reference signal at the second input, said comparator including means for delivering an output signal proportional to the dilference between the said first signal received from the piezoelectric bodies and the reference signals, and means electrically connecting the said output signal to the machine drive to stop the same and hence also stop the driving member and the carriage when the signal from the piezoelectric bodies exceeds the reference signal by a predetermined amount.
  • the invention of claim 10 including a pair of electrically insulated members located on the cam part and said piezoelectric bodies being fixed thereto, electrically insulated pressure plates located on the sides of the piezoelectric bodies opposite from the electrically in sulated members and connected to the said parts of the cam plate.
  • said knitting machine including a needled bed, and said safety means being a vibration pick-up positioned to sense vibrations of the needle bed.
  • the vibration pick-up comprises, in combination, a housing which is applied firmly against the needle bed, a mass within the said housing, a piezoelectric body which is provided with two electrodes and is gripped between a wall of the housing and one end of the mass, and a compression spring which is arranged between the opposite end of the mass and the opposed part of the housing to urge the mass towards the piezoelectric body.
  • said means responsive to the first signal being a semi-conductor, a relay means in series with the semi-conductor for controlling operation of the knitting machine, and wherein when the said first signal is of sutficient magnitude it triggers the semi-conductor to permit passage therethrough of electrical current to operate the relay means.
  • said semi-conductor being a thyristor
  • said piezoelectric body electrodes being connected through a voltage distributor and a filter to the thyristor.
  • each needle bed includes a piezoelectric vibration pick-up and-the two said pick-ups are electrically connected in parallel.
  • said means sensing reaction forces of the carriage comprises a driving member movable with the drive of the knitting machine, said monitored part of the machine being a driven part of the carriage, a force detecting piezoelectric body located on each end of the said driven part of the carriage, as seen in the direction of travel of the carriage, and said driving member having arms positioned on opposite sides of each piezoelectric body, as seen in the direction of travel of the carriage, whereby forces tending to create relative movement between the driving member and the driven parts are sensed by the piezoelectric bodies, and wherein the means responsive to reaction forces on the cam parts includes a piezoelectric body on each end of the cam part, as seen in the direction of travel, and a part of the said cam plate being positioned on the opposite side of each piezoelectric body.
  • said knitting machine including a needle bed
  • said safety means further including a vibration pick-up device positioned to sense vibration of the needle bed.
  • the vibration pick-up device comprises, in combination, a housing which is applied firmly against theneedle bed, a mass within the said housing, a piezoelectric body which is provided with two electrodes and is gripped between the wall of the housing and one end of the mass, and a compression spring which is arranged between the opposite end of the mass and the opposed part of the housing to urge the mass towards the piezoelectric body.
  • said means responsive to the piezoelectric bodies of the vibration pick-up device being a semi-conductor, a relay means in series with the semi-conductor for controlling operation of the knitting machine, and'wherein the vibration pick-up force signal is of sufiicient magnitude it triggers the semi-conductor to permit passage therethrough of an electrical current to the relay means to open the circuit delivering current to the machine driving means.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Knitting Machines (AREA)
US00199533A 1970-11-17 1971-11-17 Safety device for flat knitting machine Expired - Lifetime US3719061A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2056391A DE2056391C3 (de) 1970-11-17 1970-11-17 Strickmaschine, insbesondere Flachstrickmaschine, mit einer Sicherungseinrichtung
DE19712120824 DE2120824B2 (de) 1971-04-28 1971-04-28 Sicherungseinrichtung fuer flachstrickmaschinen

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US3719061A true US3719061A (en) 1973-03-06

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US00199533A Expired - Lifetime US3719061A (en) 1970-11-17 1971-11-17 Safety device for flat knitting machine

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US (1) US3719061A (enrdf_load_stackoverflow)
JP (1) JPS4940025B1 (enrdf_load_stackoverflow)
CH (1) CH525317A (enrdf_load_stackoverflow)
ES (1) ES396928A0 (enrdf_load_stackoverflow)
FR (1) FR2114438A5 (enrdf_load_stackoverflow)
GB (1) GB1312023A (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3838584A (en) * 1972-03-13 1974-10-01 Schieber Universal Maschf Needle breakage safety device
US3955407A (en) * 1975-04-29 1976-05-11 The Singer Company Method and apparatus for testing knitting machines
US4156357A (en) * 1978-09-05 1979-05-29 The Singer Company Carriage releasing mechanism for a flat bed knitting machine
DE2756491A1 (de) * 1977-12-12 1979-06-13 Sulzer Ag Webmaschine
US4505135A (en) * 1982-06-11 1985-03-19 Atelier De Construction Steiger S.A. Safety device for a knitting machine
US4790153A (en) * 1986-11-13 1988-12-13 H. Stoll Gmbh & Co. Safety device for flat-bed knitting machines
WO2009081532A1 (ja) * 2007-12-21 2009-07-02 Shima Seiki Mfg., Ltd. 横編機と横編機における異常振動の検知方法
CN113249885A (zh) * 2021-07-09 2021-08-13 南通海峰家居用品有限公司 一种用于窗帘生产加工的自动锁缝机
CN116971084A (zh) * 2023-06-28 2023-10-31 浙江理工大学 基于三角振动响应特性的纬编针织机故障诊断方法和系统

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2577313A1 (fr) * 1985-02-11 1986-08-14 Deude Rene Systeme electro-mecanique pour la detection par palpation d'une discontinuite ou d'une variation d'un etat de surface.
JPS63266281A (ja) * 1986-12-19 1988-11-02 Tatsuo Okazaki フロ−スイツチバルブ
WO2008152815A1 (ja) * 2007-06-13 2008-12-18 Shima Seiki Mfg., Ltd. ショックセンサを備える横編機

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3838584A (en) * 1972-03-13 1974-10-01 Schieber Universal Maschf Needle breakage safety device
US3955407A (en) * 1975-04-29 1976-05-11 The Singer Company Method and apparatus for testing knitting machines
DE2756491A1 (de) * 1977-12-12 1979-06-13 Sulzer Ag Webmaschine
US4156357A (en) * 1978-09-05 1979-05-29 The Singer Company Carriage releasing mechanism for a flat bed knitting machine
US4505135A (en) * 1982-06-11 1985-03-19 Atelier De Construction Steiger S.A. Safety device for a knitting machine
US4790153A (en) * 1986-11-13 1988-12-13 H. Stoll Gmbh & Co. Safety device for flat-bed knitting machines
WO2009081532A1 (ja) * 2007-12-21 2009-07-02 Shima Seiki Mfg., Ltd. 横編機と横編機における異常振動の検知方法
JP5362584B2 (ja) * 2007-12-21 2013-12-11 株式会社島精機製作所 横編機と横編機における異常振動の検知方法
CN113249885A (zh) * 2021-07-09 2021-08-13 南通海峰家居用品有限公司 一种用于窗帘生产加工的自动锁缝机
CN113249885B (zh) * 2021-07-09 2021-09-21 南通海峰家居用品有限公司 一种用于窗帘生产加工的自动锁缝机
CN116971084A (zh) * 2023-06-28 2023-10-31 浙江理工大学 基于三角振动响应特性的纬编针织机故障诊断方法和系统

Also Published As

Publication number Publication date
JPS4940025B1 (enrdf_load_stackoverflow) 1974-10-30
CH525317A (de) 1972-07-15
ES396928A0 (es) 1974-12-16
FR2114438A5 (enrdf_load_stackoverflow) 1972-06-30
GB1312023A (en) 1973-04-04

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