SENSING ROLL The present invention relates to a sensing roll. In the textile industry, continuous filaments or groups of filaments (a bundle) are known as "ends". "Ends-down" are ends that have broken during manufacture or processing. The roll of this invention can be called a sensor or sensor device and is particularly useful for detecting breakage of filamentary yarn ends. It can be used to activate a signal device upon the occurrence of such breakage. Filamentary yarn processing equipment must have some means of indicating when one or more ends have broken. For example, in a filter tow manufacturing machine, the tow normally comprises many ends which, when crimped and processed, make up a cigarette filter of the proper density. If an end breaks, corrective action must be taken to continue to produce the same unit density as before. If more ends break, an additional correction may be made or perhaps all ends may be sent to waste until the broken end or ends can be reinserted in the filter tow. In any event, it is often necessary to provide some sensing device to alert an operator that an end has broken or is missing. U.S. Patent No. 3,999,695, issued December

28, 1976, discloses a sensing device for detecting a running filament end while the filament is passing over a rotatable cylinder. The sensing device comprises a rotatable cylinder mounted for free rotation within a housing. The housing, which is stationary, has a fluid orifice. When a running filament is in frictional engagement with the rotatable cylinder, the cylinder rotates to thereby

overco e and rotate a counterweight (in a manner not completely disclosed) which normally blocks the fluid orifice when no filamentary yarn frictionally engages the cylinder. When the fluid orifice becomes unblocked upon the filament's engaging and rotating the cylinder, air is allowed to flow from the orifice. When the filament breaks, the counterweight rotates back into a position blocking the fluid orifice to thereby prevent the flow of air out of the orifice. This causes pressure to build up in the line through which the air passes to the orifice. The increase in pressure is sensed, e.g., by a diaphragm and an electrical switch in the manner shown in the patent. The consequence of this operation is that air normally flows from the orifice when the continuous filament is running against the rotatable cylinder. The consumption of air is costly. The fluid orifice is also in a position where it can be exposed to lint, dirt and lubricant that can be thrown off of the running filament.

This invention provides a sensing roll that is particularly useful for detecting breakage and absence of a running filamentary yarn end that frictionally engages the roll. This roll comprises a center post and a housing for the post, and is characterized in that the center post has a first and a second flat surface along its length which surfaces intersect at a first angle to form an exterior vertex, the first surface has an orifice connected to a conduit within the post to provide an air flow through the orifice. The housing is rotatable and has a first and a second interior flat surface which surfaces intersect at a second angle greater than the first angle to form an interior vertex, the first

-3- interior surface is spaced from the first surface of the post to permit air flow through the orifice in that surface, the second interior surface abutts the second surface of the post. The interior vertex of the housing is positioned upon the exterior vertex of the post to provide pivotal movement so that the first interior surface of the housing rotates in response to a torque such as that applied to the housing by a running filamentary yarn end to close the orifice in the first surface of the post and stop significant air flow through the orifice.

An advantage of the sensing roll of this invention, in comparison to the sensing device of U.S. Patent 3,999,695, is that air or other fluid flows only when an ends-down occurs. This provides obvious economies in operation. Also, the orifice which provides a flow of air or of other fluid is protected from exposure to lint, dirt, lubricant or other contaminants which could plug the orifice. The details of this invention will be described with respect to the accompanying drawings, in which

Fig. 1 is a view in elevation, partly in cross-section, of the sensing roll of this invention.

Fig. 2 is an end view, in cross-section, of the- sensing roll taken along line A-A of Fig. 1. This figure illustrates the position of the housing relative to the center post when an end is disengaged. Fig. 3 is an end view, in cross-section, of the sensing roll taken along line A-A of Fig. 1. This figure illustrates the position of the housing relative to the center post when an end is engaged. Fig. 4 is a view of part of the ends-down sensing roll shown in Fig. 1 rotated 90° to

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-4- illustrate the air fitting connection at one end of the center post.

Fig. 5 is a diagram which illustrates the normal reaction of the sensing roll of this invention to yarn ends and gravity forces; and

Fig. 6 is a schematic illustrating a typical installation involving the sensing roll of this invention.

In reference to the drawings, the sensing roll is shown as 10_; it comprises a center post 12 which can be fixed or stationary and a housing 1^ for the post.

The center post can be positioned in an operating line with one or more fiber-s inning cabinets, one for each cabinet, so that its axis is horizontal. The center post has two flat surfaces

16, 18, along a portion of its length which intersect at aτι angle to form an exterior vertex 20_. Flat surface 18 has an orifice J22 from which air or other fluid, e.g., a different inert gas, can flow.

A conduit 2Λ within the center post is connected at one end to orifice 22 and at the other end to an air supply _26_ (Fig. 6). The conduit is also operatively connected to means for signalling (signal device ^8_, Fig. 6) a change in air pressure.

An air line is connected to the air fitting 30_, which is shown in Fig. 4.

To facilitate construction, the housing 14 preferably comprises a sleeve having a cyclindrical cross-section ^2 and an outer arcuate surface 3_4 which can be engaged by a running filamentary yarn end, and an insert 36 _^ -, which is suitably secured as by use of adhesive, to the interior of the sleeve.

The insert has a pie-shaped wedge removed therefrom

to form two interior flat surfaces 38 _^ , 40_, which intersect at an angle to form an interior vertex 42. Preferably, the apex of the pie-shaped wedge extends ^" past the geometrical center of the insert as illustrated. In this manner insert 36 is oriented within the sleeve 32 so that the interior vertex 42 formed by the intersecting flat surfaces 38, 40, is above the axis of the center post 12 and lies in a plane parallel to a vertical plane passing through the axis of the center post, when the center post axis lies in the horizontal plane and the housing 14 is positioned upon the center post. The housing preferably has a cylindrical cross-section and may, of course, be made in one piece, if desired, rather than in two separate parts.

The housing 14 is positioned upon a fixed center post 12 with its interior vertex seated for pivotal movement upon the exterior vertex of the center post such that the flat surface 38 abutts flat surface 16 of the center post while flat surface 40 is spaced away from flat surface 18 of the center post in which orifice 22 is located. As illustrated, flat surface 38 is gravitationably urged against flat surface 16 but other urging means, e.g., a spring, could be used for this purpose. Also, as illustrated in Fig. 5, and discussed more fully hereinafter, the interior vertex 42 of the housing and the exterior vertex 20 of the center post, respectively, are not coincident with the geometrical centers of the housing and center post.

Frictional engagement of yarn end 44 with outer surface 34 of the housing (Fig. 3), causes the housing 14 to rotate about the exterior vertex of the

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center post until flat surface 40 abutts flat surface 18 of the center post to close the orifice 22 and stop significant air flow through the orifice.

The angle between the intersecting flat surfaces 38, 40, is preferably 70°, and the angle between the intersecting flat surfaces 16, 18, of the fixed center post is preferably 60°.

Referring to Fig. 5:

Point A is the axis of rotation of sleeve 32, Point B is the center of gravity of sleeve

32,

Point C is the center of gravity of inser ^' t

36; and

T is the torque (rotational force) exerted by yarn end 44.

When a yarn end is not in frictional engagement with the housing 14, and the moments of force around the center of rotation, Point A, are summed up then: a) The sleeve 32 produces a clockwise rotation since its center of gravity is to the right of Point A and b) the insert 36 also produces a clockwise rotation since its center of gravity is also to the right of Point A.

Thus, the normal condition is such that surface AA rests on or is supported by surface BB.

When a yarn end 44 is running in frictional engagement with housing 14, c) The friction on sleeve 32 produces a counterclockwise torque; and d) the resultant force acts to the left of the axis of rotation, Point A.

The torque produced by c) and d) is greater than that which produces the gravitational clockwise

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-7- torque. Therefore, housing 14 comprising sleeve 32 and insert 36 is rotated, causing surface DD to come to rest on surface CC and cover orifice 22.

Referring to Fig. 6 to illustrate the use of the sensing roll of this invention; a regulated air pressure and flow is supplied to the sensing roll 10 from air supply 26. The air passes through pressure regulator 4^ and flow control value 4<8 to sensing roll 10. The pressure at the roll is approximately 136 kPa. (absolute). When an end breaks or is missing for whatever reason, the center of gravity of the housing 14 causes it to rotate above the exterior vertex 20 to such extent that the orifice 22 becomes uncovered. Air then escapes from the orifice at a rate faster than it can pass across flow control value 48. This causes a loss of air pressure to pressure switch 50. The switch closes to complete an electrical circuit j52_ and activate signal device 28. When an end re-engages outer surface 34 of housing 14, the resultant torque causes the housing to rotate relative to center post 12 in the manner previously described herein until orifice 22 becomes covered and the flow of air from the orifice is stopped. Air pressure then builds up in air line 54- and pressure switch 50 deactivates to break the electrical circuit and de-engerizes signal device 54. As shown in Fig. 6, air line 54 may lead to other ends-down sensing rolls.

The sensing roll of this invention has been described with particular regard to filamentary yarn ends. However, it should be apparent that the sensing roll is equally useful in the production of continuous filaments prepared from such materials as polyesters, e.g., polyethylene terephthalate, cellulose esters, e.g., cellulose acetate, polyamides, e.g., Nylon 66 and polyolefins, e.g., polypropylene.