US3110325A

US3110325A - Pneumatic weft control means

Info

Publication number: US3110325A
Application number: US84031A
Authority: US
Inventors: Strake Lambertus Te
Original assignee: Individual
Current assignee: Individual
Priority date: 1961-01-23
Filing date: 1961-01-23
Publication date: 1963-11-12
Anticipated expiration: 1980-11-12

Description

Nov. 12, 196s 1 TE STRAKE 3,110,325

PNEUMATIC WEFT CONTROL MEANS Filed Jan. 25, 1961 United States Patent O '5,110,325 PNEUMAHC WEF? CQNTRQL BEANS Lambertus te Stralte, Huize Gallia, Deurne, Netherlands Filed Jan. 23, 255i, Ser. No. 34,0% 5 Claims. (Cl. 139-127) This invention relates to loom apparatus in general and in particular to a device for periodically drawing a loop in a thread by pulling the thread in through the open end of a hollow shaft having a suction opening closable by a valve at the closed end. This suction opening is connected to a suction device, so that with the suction valve open air enters the shaft at its open end and with the suction valve closed the loop of thread can be readily rawn out of the shaft, without a suction Iaction being exerted on it. The shaft is an improvement on the shaft disclosed in U.S. Patent No. 3,024,8l4 issued March 13, 1962, to Lambertus te Stralte, such patent showing the location and operation of the shaft in a weaving loom.

Suction of air into the hollow shaft on one side of the loom occurs between the periods in which at the same side of the loom a weft thread is blown into the shed. The frequency of operation of this suction action for one hollow shaft is thus forced to be about periods per minute at a high worling velocity of the loom.

Because of the high frequency of operation the interruption of the suction flow of the air into the hollow shaft has to occur as rapidly as possible, so that the thread can be blown immediately into the shed and hence pulled out of the shaft. This means that the suction valve must close very rapidly to disconnect the suction line.

Flow interruption and the res ltant kinetic energy or" the air column in the shaft by closure of the Valve causes very troublesome pressure wave formations. Due to the velocity of the air within the shaft, the air will be a little compressed at the closed end of the shaft immediately after the closing of the suction valve. Since the air is compressed it will expand and air will flow back toward the open end of the shaft tending to take the bottom of the U of the U-shaped loop of thread with it and entangling the thread.

lt is an object of this invention to provide improved loom apparatus. It is a specific object of this invention to provide a loop drawing shaft as described herein wherein a rapid closure of a suction valve is possible, thereby allowing operational speed of the loom to be increased, while the consumption of air in the nozzles for the weft thread need not be higher than is necessary for a direct propulsion of the thread.

ri`he invention features a provision between the open end of a hollow shaft and Vthe suction opening at the closed end an air valve for increasing the self-frequency of 'a pressure `wave occurring in the shaft as a result of closure of the valve of the suction opening. Thus the air column cannot start resonating and if a resonance might arise, a strong attenuation or damping takes place as a result of the logarith r ic decrease of the arising pressure wave.

lt is preferred that the distance between the air valve and the closed end of the shaft where the suction opening is provided, be such 'diat the period of the pressure wave as a result of the closure of the valve is about 1A of the original period determined by the length of the shaft.

Other objects, features, and advantages will become apparent when the following description is tarten in conjunction with the accompanying drawings, in which:

`FIG. l is a plan view of a shaft for drawing a loop in a length of thread;

Patented Nov. l2, 1963 The shaft is disposed at the side of the loom, near the shed. A thread running along the open end l of the shaft is drawn in a loop into the shaft when the thread is not under tension, as a result of the suction provided through a suction opening or aperture at the other end of the shaft 2.

The suction opening 2 can be closed by means of a valve 3. The opening Z is connected to a suction device via the conduit 4. rl'he shaft has formed therein a at hollow recess or longitudinally extending thread receiving slit 5 having a conduit or enlarged channel 6 along the edge or periphery of the recess 5, said slit being of a width to readily admit said loop while preventing said loop from twisting.

The shaft housing comprises a lower half 7 and an upper half i8, these halves joined by suitable means such as threaded screw Preferably the upper half 8 of the housing is made of transparent material, so that the loop of the thread, when it is present in the shaft, is visible. This is desirable when the loom is not in operation for the repair of a weaving fault, broken thread, etc.

As appears from FlG. 3, the cross-section of the shaft has the shape of a dumb-bell or bar-bell, having two conduits or enlarged channels 6 at the edges of the narrow slit 5.

In the 'lower half 7 of the housing there is formed a second aperture 9, access therethrough being controlled by a valve lil. Via the valve-housing ll and the ports l2 the second aperture 9 is in communication with the atmosphere when the valve l@ is open. The second aperture 9 communicates with the thread receiving slit 5 intermediate the opening of the slit from the shaft land the suction aperture 2.

During the suction of the loop in the thread into the recess 5 the valve 3 is in the open position and the thread enters the shaft through the opening l in the shape or form of a loop. The substantially parallel threads of the loop lie in the conduits or channels 6 because the suction pull is stronger the channels.

At the moment that the thread is to be pulled out of the shaft the valve 3 is closed and the suction action ceases.

At the same moment that the valve 3 is closed, the valve lil is opened, so that the edective length of the shaft in connection with or relative to the resonance of the air column is suddenly interrupted. The valve `lil may also be opened a short period before closure of the valve 3.

'ln order to transmit the influence of the valve lt) with the appertaining second aperture 9 in the direction of propulsion of the pressure wave into the shaft, the second aperture 9 merges into an elongated longitudinal depression i3 formed in the lower half 7 and communicating with recess 5 where the second aperture 9 opens into the recess S formed inside the shaft.

By opening of `the valve l@ as described hereinbefore a correct damping of the pressure wave occurring during closure of the valve 3 is obtained, avoiding undesirable secondary phenomena, causing the thread -to leave the position obtained when drawn into the shaft by suction and thus avoid entanglement thereof.

l claim:

l. A device for temporarily collecting a thread while preventing entanglement thereof comprising a shaft having formed therein a longitudinally extending thread receiving slit; said shaft also having formed therein a suction aperture adapted to be utilized to lower `the pressure within said slit whereby a thread disposed adjacent said slit is drawn in a loop into said slit; said slit being of a width to readily admit said lloop while preventing said loop from twisting; first means disposed to control air ilow through said suction aperture; a second aperture 3 formed in said shaft communicating with said threadreceiving slit intermediate the opening of said slit from said shaft and said suction aperture; and second means controlling air ilow through said second aperture.

2. A device for temporarily collecting a thread while preventing entanglement thereof comprising -a shaft having formed therein a longitudinally extending thread receiving slit; said shaft also having formed therein a suction aperture adapted to be utilized to lower the pressure within said slit whereby a thread disposed adjacent said slit is drawn in a loop into said slit; said slit being of a width to readily admit said loop while preventing said loop from twisting; first means disposed to control air flow through said suction aperture; a second aperture formed in said shaft communicating with said thread-receiving slit intermediate the opening of said slit from said shaft and said suction aperture; and second means controlling air iiow through said second aperture; said second means being operative to admit air ilow through said second aperture in response to ia cessation of flow through said suction aperture.

3. A device for temporarily collecting a thread while preventing entanglement thereof comprising a shaft having formed therein a longitudinally extending thread receiving slit; said shaft also having formed therein a suction aperture .adapted to be utilized to lower the pressure within said slit whereby a thread disposed adjacent said slit is dra-wn in a loop into said slit; said slit being of a width to readily admit said loop While preventing said loop from twisting; means disposed to control air flow through said suction aperture; a second aperture formed in said shaft communicating with said thread-receiving slit intermediate the opening of said slit from said shaft and said suction aperture; and means controlling air ow through said second aperture; said second aperture merging with a longitudinal depression formed in said housing and communicating with said thread-receiving slit.

4. A device for temporarily collecting a Athread while preventing entanglement thereof comprising a shaft having formed therein a longitudinally extending thread receiving slit; said shaft also having formed therein a suction aperture adapted to be utilized to lower the pressure within said slit whereby a thread disposed adjacent said slit is drawn in a loop into said slit; said slit being of a width to readily admit said loop while preventing said loop from twisting; means disposed to control air ilow through said suction aperture; a second aperture formed in said shaft communicating with said thread-receiving slit intermediate the opening of said slit from said shaft and said suction aperture; md means controlling air ilow through said second aperture; said second aperture being spaced from said suction aperture by `approximately onefourth of the distance between said suction aperture and the shaft opening of said threadeceiving slit.

5. A device for temporarily collecting a thread while preventing entanglement thereof comprising a shaft having formed therein a longitudindly extending thread receiving slit; said shaft :also having formed therein a suction aperture adapted to be utilized to lower the pressure within said slit whereby a vthread disposed adjacent said slit is drawn in a loop 'into said slit; said slit being of a width to readily admit said loopV while preventing said loop from twisting; said shaft having enlarged channels formed around the periphery of and communicating with said thread-receiving slit whereby suction pull is stronger in the channels thereby maintaining said thread in a U-shaped loop; means disposed to control air ilow through said suction aperture; a second aperture formed in said shaft communicating with said thread-receiving slit intermediate the opening of said slit from said shaft and said suction aperture; and means controlling air ilow through said second aperture.

References Cited in the tile of this patent UNTTED STATES PATENTS 1,963,098 Pool lune 19, 1934 2,089,620 Rossmann Aug. 10, 1937 FOREIGN PATENTS 1,242,687 France Aug. 22, 1960 30,514 Switzerland Nov. 16, 1955

Claims

1. A DEVICE FOR TEMPORARILY COLLECTING A THREAD WHILE PREVENTING ENTANGLEMENT THEREOF COMPRISING A SHAFT HAVING FORMED THEREIN A LONGITUDINALLY EXTENDING THREAD RECEIVING SLIT; SAID SHAFT ALSO HAVING FORMED THEREIN A SUCTION APERTURE ADAPTED TO BE UTILIZED TO LOWER THE PRESSURE WITHIN SAID SLIT WHEREBY A THREAD DISPOSED ADJACENT SAID SLIT IS DRAWN IN A LOOP INTO SAID SLIT; SAID SLIT BEING OF A WIDTH TO READILY ADMIT SAID LOOP WHILE PREVENTING SAID LOOP FROM TWISTING; FIRST MEANS DISPOSED TO CONTROL AIR FLOW THROUGH SAID SUCTION APERTURE; A SECOND APERTURE FORMED IN SAID SHAFT COMMUNICATING WITH SAID THREADRECEIVING SLIT INTERMEDIATE THE OPENING OF SAID SLIT FROM SAID SHAFT AND SAID SUCTION APERTURE; AND SECOND MEANS CONTROLLING AIR FLOW THROUGH SAID SECOND APERTURE.