Apparatus for monitoring weft thread in a weaving machine

An apparatus for monitoring a weft thread in a weaving machine operated in operating cycles, comprising:

• a sensing head for sensing a weft thread;
• said sensing head comprising a transmitter and a receiver;
• a signal processing and evaluating circuit operatively connected to said sensing head;
• said signal processing and evaluating circuit comprising:
• a detecting circuit for deriving a thread signal which is independent of extraneous effects;
• a monitoring and control circuit operatively connected to said detecting circuit for linking said thread signal to operating cycles of the weaving machine in order to monitor and control the function thereof;
• the weaving machine containing a reed comprising lamellae having a predetermined depth extension and defining a weft-thread insertion path;
• said sensing head being releasably mounted at any desired location on said reed;
• said transmitter and said receiver of said sensing head defining a path of sensing rays extending therebetween;
• at least sections of said path of sensing rays extending between said lamellae of said reed along said depth extension thereof and intersecting said weft-thread insertion path;
• and
• said path of sensing rays extends substantially along the circumference of a polygon.

An apparatus for monitoring a weft thread in a weaving machine operated in operating cycles, comprising:

• a sensing head for sensing a weft thread;
• said sensing head comprising a transmitter and a receiver;
• a signal processing and evaluating circuit operatively connected to said sensing head;
• said signal processing and evaluating circuit comprising:
• a detecting circuit for deriving a thread signal which is independent of extraneous effects;
• a monitoring and control circuit operatively connected to said detecting circuit for linking said thread signal to operating cycles of the weaving machine in order to monitor and control the function thereof;
• said transmitter generating a sensing beam of rays;
• said detecting circuit comprising a control circuit for automatically controlling the intensity of said sensing beam of rays so as to be within a predetermined intensity range and unaffected by undesired extraneous effects;
• and
• said detecting circuit further comprising a thread recognition circuit for selecting said thread signal from spurious signals.

An apparatus for monitoring a weft thread in a weaving machine operated in operating cycles, comprising:

• a sensing head for sensing a weft thread;
• said sensing head comprising a transmitter and a receiver;
• a signal processing and evaluating circuit operatively connected to said sensing head;
• said signal processing and evaluating circuit comprising:
• a detecting circuit for deriving a thread signal which is independent of extraneous effects;
• a monitoring and control circuit operatively connected to said detecting circuit for linking said thread signal to operating cycles of the weaving machine in order to monitor and control the function thereof;
• said detecting circuit comprising a sample-and-hold member having at least one input and further comprises a thread recognition circuit for recognizing a thread signal;
• said monitoring and control circuit comprising:
• a pulse generator controlled by the weaving machine;
• a clock pulse generator connected at an input side thereof to said pulse generator and at an output side thereof to said at least one input of said sample-and-hold member;
• said clock pulse generator being feed-back connected to define the start of a monitoring interval;
• a counting pulse unit for generating a sequence of counting pulses and having an output;
• said counting pulse unit being controlled by said clock pulse generator;
• a control unit controlled by said clock pulse generator;
• and
• a counting and indicating unit connected to said clock pulse generator and to said thread recognition circuit;
• said counting and indicating unit indicating coincidence of one of said counting pulses in said sequence of counting pulses and said thread signal;
• and
• a malfunction and the nature of such malfunction of the weaving machine being indicated by a change in the position in the sequence of said counting pulse coinciding with said thread signal.

An apparatus for monitoring a weft thread in a weaving machine operated in operating cycles, comprising:

• a sensing head for sensing a weft thread;
• said sensing head comprising a transmitter and a receiver;
• a signal processing and evaluating circuit operatively connected to said sensing head;
• said signal processing and evaluating circuit comprising:
• a detecting circuit for deriving a thread signal which is independent of extraneous effects;
• a monitoring and control circuit operatively connected to said detecting circuit for linking said thread signal to operating cycles of the weaving machine in order to monitor and control the function thereof;
• said detecting circuit comprises a sample-and-hold member having at least one input and further comprises a thread recognition circuit for recognizing a thread signal;
• and
• said monitoring and control circuit comprising:
• a pulse generator controlled by the weaving machine;
• said pulse generator being connected to said at least one input of said sample-and-hold member;
• an inverter connected to said pulse generator;
• a storage member supplied with pulses by said thread recognition circuit of said detecting circuit;
• and
• a control unit connected to said inverter and to said storage member for controlling the weaving machine in correspondence with said thread signal.

An appartus for monitoring a weft thread in a weaving machine operated in operating cycles, comprising:

• a sensing head for sensing a weft thread;
• said sensing head comprising a transmitter and a receiver;
• a signal processing and evaluating circuit operatively connected to said sensing head;
• said signal processing and evaluating circuit comprising:
• a detecting circuit for deriving a thread signal which is independent of extraneous effects;
• a monitoring and control circuit operatively connected to said detecting circuit for linking said thread signal to operating cycles of the weaving machine or order to monitor and control the function thereof;
• said detecting circuit comprises a sample-and-hold member having at least one input and further comprises a thread recognition circuit for recognizing a thread signal;
• and
• said monitoring and control circuit comprising:
• a pulse generator controlled by the weaving machine;
• said pulse generator being connected to said at least one input of said sample-and-hold member;
• a control unit connected to said pulse generator;
• a storage member having two inputs and an output;
• and
• a first one of said tow inputs of said storage member being connected to said pulse generator, a second one of said two inputs being connected to said thread recognition circuit and said output being connected to said control unit.

An apparatus for monitoring a weft thread in a weaving machine operated in operating cycles, comprising:

• a sensing head for sensing a weft thread;
• said sensing head comprising a transmitter and a receiver;
• a signal processing and evaluating circuit operatively connected to said sensing head;
• said signal processing and evaluating circuit comprising:
• a detecting circuit for deriving a thread signal which is independent of extraneous effects;
• a monitoring and control circuit operatively connected to said detecting circuit for linking said thread signal to operating cycles of the weaving machine in order to monitor and control the function thereof;
• and
• at least one microprocessor for effectuating switching functions of said circuits.