US3788105A

US3788105A - Needle monitoring device for circular knitting machines

Info

Publication number: US3788105A
Application number: US00232712A
Authority: US
Inventors: P Brose
Original assignee: Erwin Sick GmbH Optik Elektronik
Current assignee: Erwin Sick GmbH Optik Elektronik
Priority date: 1972-03-08
Filing date: 1972-03-08
Publication date: 1974-01-29
Anticipated expiration: 1991-01-29

Abstract

A needle monitoring device for circular knitting machines comprises a sensing device for detecting the needles moving past said sensing device and for generating an impulse for each detected needle, a preselection counter pre-set to the correct number of the needles, and a feeler detecting start and end of each machine revolution. A logic circuit receives signals from said preselection counter and said feeler and delivers a warning signal when the pre-set number has not been reached after one revolution of the machine.

Description

United States Patent [1 1 Brose Jan. 29, 1974 [75] Inventor: Peter Brose, Wolfratshausen,

Germany [73] Assignee: Firma Erwin Sick, An der Allee,

Germany [22] Filed: Mar. 8, 1972 [21] Appl. No.: 232,712

Lawson et a1 66/ 157 2,760,363 8/1956 Van Alen et a1. 66/157 3,324,685 6/1967 Schmidt et al...... 66/154 A 3,496,739 2/1970 Motin et al. 66/163 Primary Examiner.lames Kee Chi Attorney, Agent, or Firm-Darbo, Robertson &

Vandenburgh [5 7] ABSTRACT 2 Claims, 3 Drawing Figures b NUMBER [52] [1.8. CI. 66/157, 66/163 [51] Int. Cl D04b 35/10 [58] Field of Search 66/157, 163, 166, 165

[ 56] References Cited UNITED STATES PATENTS 3,646,542 2/1972 Anthony 66/157 X 3,529,445 /1970 Brose 66/157 3,577,750 5/1971 Venczez 66/157 3,659,437 5/1972 McArthur et a1.. 66/157 3,509,739 5/1970 Gottschall 66/157 (REVOLUTION DETECTOR KNITTING RIB CYLINDER I NEEDLE I ozrscron MACHINE OPERATION CONTROL FIXED COUNTER I I l 1 Y 1 I I 1 BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to a needle monitoring device for circular knitting machines comprising a sensing device for detecting the needles moving past said sensing device and for generating an impulse for each detected needle.

In a prior art needle monitoring device of this type (my U.S. Pat. No. 3,529,445) there is a sensing device producing an impulse for each detected needle and thus a composite a.c. output signal. An evaluating circuit is connected to the sensing device, said evaluating circuit responding to irregularities of the a.c. signal, namely to the time interval between consecutive impulses delivered by the sensing device on the basis solely of reflections from the needle. The prior art device makes use of the fact that both a broken and a bent needle results in a change of the time interval between consecutive needle impulses. If a needle is broken, the time interval from the previous needle impulse to the next needle impulse is twice the normal value. A bent needle results in a shorter time interval between a first pair of needle impulses and a longer time interval to the next following needle impulse or vice versa. In the prior art device, the evaluating circuit comprises an integrating network to which a constant input signal is applied, said integrating network being connected to be reset by the impulses delivered by the sensing device A tripper device is provided which responds as soon as the output of the integrating network exceeds a desired threshold.

Knitting machines can have variations in the time interval between consecutive needle impulses during a machine revolution due to needle vibrations without any needle being broken or deformed. While these do not affect the operation of the knitting machine, they can improperly be interpreted by the aforesaid prior art devices as indicating a broken or bent needle.

It is' an object of the invention to provide a needle monitoring device for circular knitting machines, in which only needle impulses are processed and which operates in a purely digital manner.

- The. needle monitoring device of the invention is characterized by a. a preselection counter pre-set to the correct number of the needlesand connected to count the needle impulses, said preselection counter producing different output signals depending on whether the pre-set number has been reached or not,

b. a feeler for detecting start and end of a machine revolution and c. a logic circuit providing a logic configuration of the signals from said preselection counter and said feeler to produce a warning signal, when the preset number has not been reached after one revolution of the machine.

Preferably in embodiment of the invention the output signal of said preselection counter is changed from L to 0 upon reaching said pre-set number; the preselection counteris reset to zero at the beginning of the next revolution of the machine; and the feeler produces a signal 0 during each revolution of the machine and a signal L upon completion of each revolution; and the two signals from the preselection counter and from the feeler are logically combined by an AND-gate.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow diagram" of a device of the invention;

FIG. 2 shows the associated pulse time diagram; and

FIG. 3 is a perspective and diagrammatic view of part of a conventional knitting machine having photoelectric detectors according to the invention.

DESCRIPTION OF SPECIFIC EMBODIMENT The drawings illustrate a circular knitting machine I the revolutions of which are detected by a feeler 2 which may take the form of a photoelectric detector looking at a stripe 10 on the cylinder of the knitting machine. Feeler 2 delivers an output signal 0,." duringeach revolution and an output signal L, between the the revolutions. That is, when the photoelectric detector 2 is looking at the stripe 10 the 0, signal results, while when it is looking at the gap 11 between the ends of the stripe the L, signal results. This has been shown in the first line of FIG. 2. Two

photoelectric detectors

3 and 4 detect the rib needles l2 and the cylinder needles 13 respectively when these needles are moved past said sensing heads. The impulses received from the

sensing heads

3 and 4 are counted by a counter 5 which has been preset to count only to a given number. When the machine has n cylinder needles and n rib needles, the sum of all needles provided on the machine is n n n ..The counter is pre-set to this number. The counter delivers an output signal L as long as the pre-set number has not yet been reached. Upon reaching the pre-set number, the output signal of the preselection counter 5 is changed to 0 The output signals of feeler 2 and counter 5 are applied to the two input terminals of an AND-gate 6. The output of the AND-gate 6 controls the operation of the machine, as indicated at 7.

During the first revolution (the left side of FIG. 2), all needle impulses are present. It will be noted that during the first revolution and during the interval between it and the second revolution either the signal from feeler 2 or the signal from counter S is O, at the input terminals of AND-gate 6. Thus nothing passes through the AND-gate 6. At the beginning of the second revolution, the counter has already been reset to zero because it had counted out (up to the preset number) by the end of the preceding revolution. In FIG. 2 it is assumed that a rib needle is missing at 8 during the second revolution, so that one impulse is missing accordingly. Thus the counter does not reach the preset number during this revolution and the output of the counter does not return to 0 The signal L then continues beyond the termination of the second revolution. Thus, when the output of feeler 2 becomes also (L,) at the end of the second revolution, the AND-gate delivers a corresponding signal (L,,) which (see last line of FIG. 2) causes the machine to be switched-off immediately following the end of the second revolution.

The device described can be used in addition to a monitoring device described in US. Pat. No. 3,529,445, in order to provide an additional check and to eliminate mistaken operations which could occur in a device of this patent due to needle vibrations. Of

course, only one pair of photoelectric sensing heads need be provided, the impulses of which are, on one hand, counted. and, on the other hand, checked for their time intervals.

As will be apparent to anybody skilled in the art, L and O are two binary states. For example, L may mean voltage" and may mean no voltage" or vice versa.

The revolution feeler may be of any conventional type and may, for example, comprise a slip ring or, alternatively, photoelectric means.

I claim:

1. In a needle monitoring device for use with a circular knitting machine operating in revolutions with intervals between revolutions and having a given number of needles, said device having needle detector means producing an impulse each time a needle passes said means, said device comprising:

revolution detector means for detecting the start and end of a machine revolution and for indicating whether the machine is performing a revolution or in the interval between revolutions;

counter means connected to said needle detector means to count said impulses to said number repeatedly and to indicate whether it is in the process of counting to said number or is awaiting an impulse to commence said count; and

circuit means connected to said revolution detector means and to said counter means to produce an error signal when the count in the counter means has not reached said number by the end of a revolution. 2. In a needle monitoring device for use with a circular knitting machine operating in revolutions with intervals between revolutions and having a given number of needles, said device having needle detector means producing an impulse each time a needle passes said means, said device comprising:

revolution detector means for detecting the start and end of each revolution of said machine and producing output signals of one type during the revolutions and producing output signals of a second type in the interval between revolutions; counter means connected to said needle detector means to count said impulses to said number repeatedly and producing output signals of said one type while it is in the process of counting up to said number and of said second type after the count reaches said number and before the count recommences; and V circuit means connected to the revolution detector means and to the counter means to produce an error signal when said signals of said one type occur simultaneously.

:.-UNITED STATES PATEN OFFICE CER'TIFICATE OF CORRECTION Patent No. 3,788,'l05 Dated January 29, 1974 Inventor(s) Peter Brose dIt is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected 'as shown below:

In the address of the Assignee, delete. "An der Allee. and insert -Waldkirch-.

Signed and. sealed this 11th dayof June. 197k;

(SEAL) I v Attest: V I

EDWARD H.FLETC-HER,JR. c. MARSHALL 1mm Attesting Officer Commissioner of Patent;

-'ORM PO-1050 (10 69) USCOMM-DC 60375.]:59

' us, GOVERNMENT manna omc: inn o-ua-au.

Claims

1. In a needle monitoring device for use with a circular knitting machine operating in revolutions with intervals between revolutions and having a given number of needles, said device having needle detector means producing an impulse each time a needle passes said means, said device comprising: revolution detector means for detecting the start and end of a machine revolution and for indicating whether the machine is performing a revolution or in the interval between revolutions; counter means connected to said needle detector means to count said impulses to said number repeatedly and to indicate whether it is in the process of counting to said number or is awaiting an impulse to commence said count; and circuit means connected to said revolution detector means and to said counter means to produce an error signal when the count in the counter means has not reached said number by the end of a revolution.

2. In a needle monitoring device for use with a circular knitting machine operating in revolutions with intervals between revolutions and having a given number of needles, said device having needle detector means producing an impulse each time a needle passes said means, said device comprising: revolution detector means for detecting the start and end of each revolution of said machine and producing output signals of one type during the revolutions and producing output signals of a second type in the interval between revolutions; counter means connected to said needle detector means to count said impulses to said number repeatedly and producing output signals of said one type while it is in the process of counting up to said number and of said second type after the count reaches said number and before the count recommences; and circuit means connected to the revolution detector means and to the counter means to produce an error signal when said signals of said one type occur simultaneously.