EP0516589A1

EP0516589A1 - Threading apparatus in a loom

Info

Publication number: EP0516589A1
Application number: EP92810389A
Authority: EP
Inventors: Masanobu c/o K.K. Toyoda Sakai
Original assignee: Toyoda Jidoshokki Seisakusho KK; Toyoda Automatic Loom Works Ltd
Current assignee: Toyota Industries Corp
Priority date: 1991-05-27
Filing date: 1992-05-22
Publication date: 1992-12-02
Also published as: JPH04352851A; JP2890903B2

Abstract

To provide a threading apparatus that does permit a workman to perform threading operation in a loom without requiring him to use his both hands. Adjacently to the inlet (11a) of a main nozzle (11) is provided a sensor comprising a light emitter (3) and a light receiver (4) located in opposing relation to each other with respect to passage of a weft to be passed into the nozzle, and the light receiver 4 is connected to a control unit (5) which controls supply of threading air to the main nozzle in response to a control signal from the sensor.

Description

The present invention relates to an apparatus for threading a device of a loom with a yarn. More specifically, it relates to an apparatus for threading a main weft inserting nozzle of a jet loom with a weft.
In threading a main weft inserting nozzle of a jet loom with a weft, or passing a weft through the main nozzle, it has been a practice that a workman brings the leading end of weft close to the inlet of the nozzle while holding it with his left hand and then operates a threading switch with his right hand or a foot-operated valve with his foot thereby to allow threading air to be supplied to the main nozzle so that the weft is passes through the nozzle by air flow.
Publication of Unexamined Japanese Patent Application No. 62-57968 (1987) discloses a loom having a weft feeler which is provided adjacently to the inlet of a main weft inserting nozzle for detecting a weft break occurring between a weft storage device to the nozzle during normal weaving operation of the loom.
Thus, conventional threading operation in a jet loom which has required a workman to use his both hands to do the job is disadvantageous because it is poor in workability, consumes much time and calls for skill of the workman.
Since the workman has to use his both hands for threading, it is practically impossible for him to make simultaneous adjustment of flow or pressure of threading fluid.
The feeler in the apparatus according to the above-cited Publication JP No. 62-57968 is adapted only to detect a weft break occurring during loom operation and no provision is made to facilitate threading operation. With this conventional apparatus, it is difficult to perform weft threading.
It is an object of the present invention to provide a threading apparatus which can permit a workman to perform threading operation without use of both his hands, thereby facilitating the operation and allowing the workman to do other jobs than the threading.
To achieve the above object, there is provided a threading apparatus comprising a sensor disposed adjacently to a yarn inlet of a device which is to be threaded with a yarn and a control, operable only when the loom operation is at a stop so as to permit yarn threading fluid to be supplied to said device in response to a signal from said sensor.
The invention is particularly suitable for application to a main weft inserting nozzle in a jet loom, in which case the device to be threaded with a yarn is the main nozzle.

[EMBODIMENTS]

The following will describe an embodiment of threading apparatus according to the present invention with reference to the accompanying drawings. The Figures illustrate the following:

FIG. 1 is a schematic diagram showing first embodiment of threading apparatus of the present invention as applied to a main weft inserting nozzle of a jet loom.
FIG. 2 is a schematic diagram showing second embodiment of threading apparatus of the invention as applied to a drum type weft measuring device.

Referring firstly to FIG. 1, a schematic diagram showing an embodiment of the invention wherein the threading apparatus is applied to a main weft inserting nozzle in a jet loom, a main nozzle 11 is attached to a slay (not shown) of a jet loom.
The main nozzle 11 has an inlet 11a into which a weft is inserted and an injection pipe 12 of which the weft comes out with air to be blown into a warp shed.
Adjacently the nozzle inlet 11a is disposed a sensor comprising a light emitter 3 and a light receiver 4 positioned in opposite relation to each other with respect to passage of a weft to be introduced into the nozzle. The light emitter and receiver 3, 4 are fixed to brackets 2 which are in turn fixed to loom frame 1.
The light receiver 4 is connected to a control unit 5 which is adapted to control supply of threading air to the main nozzle 11, in response to a control signal from the sensor. The control unit 5 is in turn connected to a coil of an electromagnetically-operated valve 6. The valve 6 shown in the embodiment is a two-way valve whose input is connected to an air supply 7 by way of a throttle valve 8 so that compressed air of a predetermined pressure is supplied to the valve 6. The output of the valve 6 is connected to the main nozzle 11 so that the compressed air for threading is fed to the main nozzle 11 when the valve is opened.
The control unit 5 has a loom-stop sensor (not shown) connected thereto and is operable only during a stop of the loom. That is, in view of the situation that threading operation is usually performed when the loom is at a stop, the control unit 5 is adapted to be operable effectively to respond to a signal from the sensor 3, 4 only during a stop of the loom. Thus, the control unit 5 is kept inoperable even if a sensor signal is transmitted thereto during normal operation of the loom. The sensor according to the present invention differs in this respect from the sensor disclosed in the above-cited Publication No. No. 62-57968 which is adapted to detect a weft break occurring between a weft measuring device and a main nozzle during loom operation. Since a sensor for detecting a weft-break is not used when the loom is at a stop, this sensor may be used also to function as the sensor 3, 4.
Additionally, since threading operation is performed at crank angles of the loom within a given range, it may be so arranged that the control unit 5 is conditioned to be operable at the crank angles of such specific range.
Threading apparatus of the above-described embodiment operates as follows. When a workman brings the leading end of a weft 10 with his left hand 9 close to the nozzle inlet 11a for threading the nozzle 11 with that weft 10, light between the light emitter and receiver 3, 4 is blocked by workman's hand 9, thereby decreasing the level of the light received by the light receiver 4. In response to such a decrease in the light level, the sensor generates a signal to the control unit 5. When such a signal is received during a stop of the loom, the control unit 5 responds effectively to the sensor signal, thereby actuating the electromagnetically-operated valve 6 to open and allowing threading air from the air source to be supplied to the main nozzle 11. Threading air flowing through the nozzle 11 creates suction in the region adjacent the nozzle inlet 11a, acting on the leading end of weft 10. The weft 10 is pulled into the main nozzle 11 under the influence of this suction when the workman releases its end, and the weft is passed through the main nozzle. Thus, weft threading is completed.
Though the threading apparatus of the invention has been described in the above embodiment as applied to a main nozzle of a jet loom, it is applicable to a drum-type weft measuring device, as well.
An embodiment of threading apparatus as used for threading such drum-type weft measuring device will be now described with reference to FIG. 2. Reference numeral 21 designates a drum of conventional drum-type weft measuring device and 21a depicts a drum inlet, respectively. As indicated by a dash-and-dot line, it is so arranged that compressed air is supplied via an electromagnetically-operated valve 6 to the drum 21. Adjacently to the drum inlet 21a is disposed a sensor comprising a light emitter 2 and a light receiver 3′. These light emitter 2 and receiver 3′ are connected to a control unit 5 which is operable to activate the valve 6 to open thereby supplying air to the drum 21 in response to a sensor signal generated when the light from the emitter 2 to the receiver 3′ is blocked during a stop of the loom.
To provide a threading apparatus that can permit a workman to perform threading operation in a loom without requiring him to use his both hands.
Adjacently to the inlet 11a of a main nozzle 11 is provided a sensor comprising a light emitter 3 and a light receiver 4 located in opposing relation to each other with respect to passage of a weft to be passed into the nozzle, and the light receiver 4 is connected to a control unit 5 which controls supply of threading air to the main nozzle in response to a control signal from the sensor.
As it is now apparent from the foregoing description, the threading apparatus of the present invention according to which threading fluid or air is supplied automatically when a workman's hand is placed adjacent the inlet of a device to be threaded, the workman can bring the weft end close to the device while holding it with one hand, or with both hands if necessary, thus permitting him to easily pass a yarn through a small-diameter hole of the device such as a main weft inserting nozzle of a jet loom. Furthermore, workability in threading operation can be improved greatly because the workman need not manually operate a threading control switch as practiced heretofore. Thus, success in threading is improved and the time for such operation is reduced. Additionally, the workman is allowed to use the other hand for controlling a throttle valve for adjustment of flow of fluid.

DESIGNATION OF REFERENCE NUMERALS

1 Loom frame
3; 2 Light emitter
4; 3′ Light receiver
5 Control unit
6 Electromagnetically-operated valve
11 Main nozzle lla Main nozzle inlet
21 Drum
21a Drum inlet

Claims

Threading apparatus in a loom comprising a sensor (3, 4; 2, 3′) disposed adjacently to a yarn inlet of a device (11, 11a, 12) which is to be threaded with a yarn and a control (5) operable only when the loom operation is at a stop so as to permit yarn threading fluid (7) to be supplied to said device (11, 11a, 12; 21, 21a) in response to a signal from said sensor (3, 4; 2, 3′).
Threading apparatus in a loom comprising a first sensor (3, 4; 2, 3′) disposed adjacently to a yarn inlet (11a) of a device (11, 12; 21, 21a) which is to be threaded with a yarn and a control unit (5) that permits yarn threading fluid (7) to be supplied to said device (11, 12; 21, 21a) in response to a signal from said sensor (3, 4; 2, 3′).
Threading apparatus as claimed in claim 2, further including a loom-stop sensor connected to the control unit (5) and putting the control unit (5) into operation only when the loom is at a stop.
Treading apparatus as claimed in claim 3, further including a second sensor putting the control unit (5) into operation only when the loom is stoped at a specific range of the crank angle position.
Threading apparatus as claimed in any of claims 1 to 4, said first sensor (3, 4; 2, 3′) being an optical sensor.
Threading apparatus as claimed in claim 5, said optical sensor including a light emitter (3; 2) and a light sensor (4; 3′) placed on opposite sides of the path of the yarn to be threaded into the device.
Treading apparatus as claimed in any of claims 1 to 6, said first sensor (3, 4; 2, 3′) actuating a threading fluid valve (6) when the control unit (5) is oparable and signal of the first sensor (3, 4; 2, 3′) is changed by the operator.
Treading apparatus as claimed in any of claims 1 to 7, wherein the threading fluid is air.
Threading apparatus in a loom according to any of claims 1 to 8 wherein said device (11, 11a, 12) which is to be threaded with a yarn, is a main weft inserting nozzle of a jet loom.
Air jet loom with a thereading apparatus as claimed in any of claims 1 to 9.