US3315916A - Bobbin construction - Google Patents

Description

April 1967 M. SCAGLIA BOBBIN CONSTRUCTION 2 Sheets-Sheet 1 Filed June 2, 1965 April 25, 1967 M. SCAGLIA BOBBIN CONSTRUCTION 2 Sheets-Sheet 2 Filed June 2, 1965 United States Patent Oflice 3,315,916 Patented Apr. 25, 1967 BOBBIN CBNSTRUCTIGN Mario Scaglia, Bergamo, Italy, assignor to M. Scaglia S.p.A., Bergamo, Italy Filed June 2, 1965, Ser. No. 460,698 Claims priority, application Italy, July 6, 1964,

10 Claims. (Cl. 242-118.6)

This invention relates to improvements in the construction of bobbins of the type adapted for having yarn wound thereon. In particular, the yarn is of the kind spun from man-made fibers.

The general form of construction of the bobbin includes a tube with end flanges mounted on the tube. When yarn is wound on such a bobbin, the yarn exerts a lateral force on the flanges tending to displace the flanges off the tube. If an opening or fissure should be formed in the joint between the adjacent surfaces of the flanges and tube, it is possible to snag the yarn in such fissure which will result in breakage in the yarn when it is unwound from the bobbin.

It is an object of the invention to provide an attachment between the flanges and the tube, in which there will be virtually no possibility of the formation of a fissure or opening between the flanges and the tube during Winding of the yarn whereby the danger of snagging yarn is substantially completely eliminated.

It is a further object of the invention to provide an improved method and means for securing the flanges to the tube such that the flanges are pro-stressed in a manner to resist the formation of fissures or openings between the flanges and tube.

Yet another object of the invention is to provide means for elastically and adjustably controlling the magnitude of such pro-stressing. Heretofore a substantially cylindrical metallic tube was employed whereon the yarn is wound, and both ends of the tube are upset and upturned against related flanges, which are thereby secured on the tube parallel with each other and thus perpendicular to the tube axis. The flanges can be made of a suitable material such as plastic, Bakelite, metal, or the like. The flanges must be adequately secured on the bobbin tube to prevent the formation of fissures or openings between the inner surfaces of the flanges and the outer surface of the tube when the bobbin is being wound with the related yarn. In particular, since yarns spun from manmade fibers can be wound under strong tension, high stresses are exerted by the yarn being wound, both in a radial direction on the tube and in a lateral direction against the flanges. This results in bending stresses in both flanges, tending to deflect the flanges outwardly off their seats at both tube ends. As a direct consequence thereof, spaces are formed between the flanges and the tube, and the yarn may be engaged thereinto under strong tension, whereby when such bobbins are to be unwound, yarn breakages and the like are experienced.

Known arrangements which have attempted to overcome the above have been based partly on improvements in the strength and stiffness of the connection between the flanges and tube and partly on the provision of mechanical means to prevent the formation of said spaces. Other arrangements include means to fill such spaces simultaneously with their formation, in such a manner as to insure continuity of the surfaces on which the yarn is wound. Many of the above-stated known arrangements have been presented in patents by the applicant. Such arrangements have not proven to be entirely satisfactory.

The present invention, however, is directed to an entirely novel concept.

In this respect, the invention is characterized by the provision of a suitable elastic pre-stressing which is produced by suitable means, in a direct or indirect way, in each flange, which is fitted in a related seat in the tube. In other words, a system of inwardly directed internal stresses is produced in each flange to thereby counteract and resist the laterally applied outwardly directed stresses which are produced when the yarn is being wound on the bobbin.

The above characteristic feature of the invention can he obviously carried into effect in different practical forms, both as regards the means for producing said elastic pro-stresses, and the shape, arrangement and construction of said means, as well as the number and location of such means with respect both to the flanges and to the bobbin tube.

According to a first embodiment of this invention, the means for producing said elastic pre-stresses in the flanges, comprises at least one elastic ring seated in a suitable annular groove that extends in a generally radial plane extending substantially perpendicular to the tube axis, in the inner peripheral wall of each flange, said annular groove being delimitated all along its base by the outer cylindrical surface of the tube which constitutes a seat for the flange. The end of the tube is upset and upturned against the flange to firmly secure it to said tube. By the presence of at least one groove of the abovestated type, the axial elasticity of the flange is considerably increased, whereby, when the tube end is upturned against the flange in order to secure it to said tube, the elastic ring previously seated in said groove is squeezed and thus exerts a given elastic pressure which is transmitted in all direc tions against the groove wall and particularly in the required axially inwards directed sense. Stated otherwise, the inside wall of the groove will be pro-stressed in an inwards direction of the bobbin, whereby the flange is forced to elastically engage the tube seat at a given elastic stress, which will preferably always be greater than the outwardly directed stress exerted on the yarn while it is being wound under strong tension on the bobbin. This will prevent the flange from being displaced out of its seat and off the bobbin, as well as the formation of spaces or fissures in which yarn can be engaged.

According to another embodiment, the means for producing the inwardiy directed elastic stress, advantageously consists of only one or more ofthe above: annular grooves without the insertion of an elastic ring. Such grooves increase the axial elasticity of the flange, which as a consequence of the upsetting and upturning of the end of the bobbin tube, will generate the required elastic pre-stress.

In yet another embodiment such means may comprise a spring member which elastically engages each flange and applies an inward elastic pre-stress, which tends to elastically maintain the initial position of the flange on the tube seat.

Said spring member may be a spiral spring, a cup-shaped spring, a flat spring, or the like, which may be adjustable to vary the magnitude of pro-stress exerted on the flanges.

To additionally improve the locking action by which the flanges are retained in their seats on the tube, and to positively prevent the minute displacement of such flanges, with the consequent formation of fissures and spaces, the tube seat is defined as an annular recess in the outer surface of the tube, with an outwardly inclined inner face. Such inclined face cooperates with a mating portion of the flange wall in such a manner that contact between said two walls will always be established at the outer cylindrical surface of the tube for all magnitudes of stress to which the flange is subjected.

The above and further objects, features and advantages of this invention will become more apparent fromthe following description taken with the accompanying drawing showing a number of embodiments of the invention given by way of non-restrictive example. In the drawing:

FIGURE 1 is a side view, partly in section, of a bobbin wherein the flanges thereof are secured to the tube according to a first embodiment of the invention;

FIGURE 2 is an enlarged view of a detail of one end of the bobbin of FIG. 1;

FIGURE 3 is an enlarged axial section of the end of a bobbin, showing a second embodiment of the invention;

FIGURE 4 is an enlarged view, partly in section, of the end of a bobbin, showing a third embodiment of the invention;

FIGURE 5 shows partly in axial section, a plastic plug and integral sleeve which is adapted for insertion into an end of the bobbin tube; and

FIGURE 6 is a cross-section of the plug and a bush as taken along line VIVI of FIG. 5.

Referring now to the drawing, and in particular to FIGS. 1 and 2 thereof, therein is shown a bobbin assembly A which is particularly adapted to accommodate yarn spun from man-made fibers, and which, as already well known, consists of a metal tube B having side flanges C slipped over both ends of the tube. The flanges C are secured on the tube B in a manner which will be described in more detail later on. Such basic structure of the bobin is completed by a pair of plastic plugs 10, forced into the bore 12 of the bobbin tube, with a plastic tube insert 14 clamped between both plugs and two bushes 16 in the plugs 10. Such bushes preferably are constituted of bakelized fabric.

As well known, the yarn (not shown) is wound on the cylindrical surface 18 of the tube B, which therefore must be joined, without interruption, with the inner annular sides 20 of flanges C, against which the yarn comes to rest. The wound diameter of the yarn is usually equal to diameter d of the flanges C. As already known, while the yarn is being wound, a double system of forces is produced, of which one, acting in the direction of the arrows X, is not detrimental to the structural integrity of the bobbin assembly, since it is resisted by the tube itself. The other force system acts in the direction of arrows Y and will be hereinafter referred to as lateral stresses. Such lateral stresses act to drive the flanges longitudinally of the central tube B, causing the flanges C to creep in the direction of arrows Y against the reaction forces which are generated by the means by which the flanges are locked to the tube. Theoretically, it may be conceived that each flange, under the action of its own system of lateral stresses, will be bent outwardly around the corresponding end D of the bobbin tube. Due to the above-stated bending stress, the sides 20 tend to deflect away from the surface 18 at the surface joints 22, 24, which would produce spaces between surfaces 18 and 20. Such deflection is detrimental to the operational reliability of the bobbin, since the yarn can be snagged in such spaces, with consequent breakage of yarn and lack of serviceability of the bobbin.

In the embodiments shown in FIGS. 1 and 2, there is provided means adapted to exert elastic action to produce elastic stresses designed to resist and overcome the lateral stresses acting in the direction of arrows Y. Such means comprises a groove F cut in the inner periphery of each flange C, and an elatic ring M seated in the groove F, be-- fore the flange is forced over the tube. Each flange is, formed with a bore by which it can he slipped over the corresponding end D of tube B, and is locked therein by the engagement of said flange C into the seat H that is formed on the end D, as well as by the upsetting and up turning of end portion 26 of the metal tube against the corresponding flange. The upturned portion 26 in cooperation with the conical section 28 of the flange, will result in the production of compression stress exerted on the flanges and bobbin in the direction of the arrow Z, and thus in a firm securing of flange C in seat H.

Obviously, the above construction described for the left flange is appropriate also for the right flange.

While in FIG. 1 the groove F is shown wholly filled A. by the ring M, in FIG. 2 the same groove appears to be only partly filled by said ring. This is the case because FIG. 2 represents an intermediate stage of installation, the metal edge 26 being not yet fully upturned and pressed against the cone portion 28 of the flange, as in FIG. 1.

As shown in the drawing, the ring M becomes wholly enclosed within the bobbin, i.e., in the groove F thereof, and thus is enclosed and protected against any external action which would tend to cause premature wear thereof.

The ring M in the groove F exerts an elastic action on the flange C, whereby a system of elastic stresses is produced within the flange. The stresses of the latter system are designed to act in opposition to the lateral forces which act on the flanges in the direction of arrows Y. In fact, when the edge 26 is upturned against the flange C, the side walls of groove F, by which the axial resilience of said flange is materially increased, are drawn nearer by a given amount, depending on the force exerted by said edge 26, whereby the material of elastic ring M is deformed in both radial and axial directions, thus filling the entire space of the thus deformed groove F. As a consequence thereof, the ring M will exert an elastic force on the flange C and in particular on the walls 11, 13 of such flange, since said elastic ring tends to resume its initial shape and because the elastic limit of both the flange and the ring M is never exceeded when the metal edge 26 is upturned. Thereby, a force is exerted by the ring on both walls 11, 13, whereby a force is exerted in an axial or lateral direction opposite to Z on the wall 11 and in the direction of Z on wall 13. It is the latter force that is effective for the purpose of always maintaining continuity between the outer surface 18 of the tube and the side surfaces 20 of the flanges. The abovestated elastic action is permanently exerted, due both to the tendency of ring M to resume its initial shape and also of groove F to return to its initial form. Such elastic action constitutes a pre-stress having the function of counteracting the lateral stress produced by the winding of yarn acting in the direction of arrows Y. Such prestress must always exceed, at least by a small amount, the stresses that are to be resisted, whereby the wall 20 is permanently kept in contact with the surface 15 of seat H, thus preventing the existence of objectionable spaces between the flanges and the tube, and thereby eliminating the possibility that the yarn can be caught therein.

As can be seen in FIG. 2, the wall 15 of the seat H that is formed on the tube D, is conveniently inclined outwardly, thus having a cone shape. The wall 17 of flange C is adjacent wall 15 and is inclined with respect thereto. Thus, wall 17 may be inclined or may be perpendicular to the tube B. As can be seen in the drawing, the recess in the tube defining the seat H, is bounded by the above wall 15, and the walls 15, 17 come into contact with each other after the edge 26 has been upturned against the flange C. The inclination of said walls 15, 17 is a further contribution to a positive prevention of the existence of spaces at surfaces 22, 24. In this respect the force Y exerted by the winding of the yarn, tends to bend the flange C outwardly around a rotation center 19, in the direction of arrow V, and the wall 17 attempts to move upwards by sliding along the wall 15, and out of the seat H. As a consequence of such sliding motion, a fissure-like void would be formed between the surface 18 of the tube B and the surfaces 20 of the flanges C. Such formation of a void is prevented by the fact that contact is always maintained between the walls 15 and 17 as a consequence of their relative inclination.

It is possible to use one or more grooves F 'without the elastic rings M, as a means to exert the elastic action by which the required pre-stressing of flanges C is produced. In such a case said grooves are left empty. As can be readily appreciated, the local resilience of the flange C is increased by the pressure of such grooves, whereby an elastic action is exerted for counteracting the stress Y exerted by the yarn.

A further embodiment is shown in FIG. 3 for bobbin A. In more detail the flange C, which is engaged as usual by its section G in the seat H of the bobbin tube, is elastically acted upon by a cup-shaped spring N that it slipped over the end D of tube B. The edge 26 of said end D of tube B is upset and upturned against the spring N, in order to produce the required elastic action in the direction of the arrow Z, and by which the flange C is elastically pre-stressed, thereby to counteract and to overcome the above-stated lateral stresses Y exerted by the yarn.

In this latter case, only the wall 15 of seat H is inclined, while the wall 17 of the flange is straight and perpendicular to the bobbin axis.

In the third embodiment of bobbin A", as shown in FIG. 4, the means by which the flange C is connected with the tube B, comprises a spiral spring P that is slipped over a pin 21 which is secured to tube B and which projects beyond the flange C. The elastic load that is exerted in the direction of the arrow Z on flange C can be properly adjusted by means of a nut 23, that is screwed on a threaded end of said pin 21 and by which the spring P can be more or less compressed by the washer 25. The compression of the spring constitutes an elastic load that counteracts and overcomes the stress exerted by the yarn winding, which tends to drive the flange off the tube.

In all cases as considered above, the magnitude of the elastic pre-stress that is directly or indirectly applied to the flange C, can be adjusted when assembling the bobbin. Amongst others, the limit value of pre-stressing to be imparted to flanges C in the case of the embodiment in FIGS. 1 and 2, is defined by the increase in the resistance that is opposed by the elastic ring M while being gradually deformed in its groove F as a consequence of upsetting and upturning the edge 26 of tube B. Thus, the ring M acts also as an indicator of the magnitude of pro-stressing that is imparted to the flange, whereby the magnitude can therefore be visually adjusted according to requirements.

Even in the embodiment of FIG. 3, the elastic force exerted by the spring N can be adjusted according to requirements by adjusting the degree of upsetting and upturning of the edge 26. The same can be said with regard to the embodiment in FIG. 4, wherein the elastic action can also be adjusted by varying the degree of threaded engagement of the nut 23 on its threaded pin.

Referring now to FIGS. 5 and 6, there is shown a plastic plug which is secured with a related bush 16 for being inserted into the metal tube B by forcing them as an assembly through the inwardly projecting rims at the seats H in the tube ends C. Thus said plug is required to be highly resilient to allow it to be forced through said rims, the diameter of which is smaller than the plug diameter 27.

For the above purpose, a plurality of ribs 29 are advantageously provided in the plug. Such ribs extend in an intervening space 31, between an inner cylindrical hub 33 that is locked on the related cylindrical surface of bush 16 and an outer cylindrical wall 35 that is adapted to be inserted into the metal tube B. All the ribs 29 extend tangentially from hub 33, which is an important feature of the invention, since said arrangement results in a material increase in the radial resilience of plug 10.

In fact, when the assembly of plug 10 and bush 16 is inserted into the related end opening of bobbin tube B, the edge 27 is deformed and narrowed to pass through the end D, such deformation being facilitated by the presence of ribs 29 which are readily deformed under the stress applied to the cylindrical wall 35. After the plug 10 has reached its final position, wherein said rim at the end D of the tube becomes engaged in the groove 37, the tangential ribs 29 will resume their normal shape, thereby bringing the cylindrical wall 35 into contact with the associated wall of bobbin tube B, and therefore each plug 10, on reaching its final position, wholly accommo- 6 dates itself within the inside shape of the related section of bobbin tube B.

The increase in the elasticity of plug 10, as required for attaining the above purposes, cannot be attained when the ribs are not arranged in a substantially tangential direction. Forexample, if the ribs are radially arranged, a much lower elasticy is obtained, since such ribs would be acted upon by a compression stress instead of a bending stress, thereby offering a higher resistance to deforrnation.

While the invention has been described in detail, it is to be understood that the description is for the purpose of illustration only and is not definitive of the limits of the inventive concept. Numerous changes in the details of construction and arrangement of parts will be apparent to those skilled in the art within the scope and spirit of the invention as defined in the attached claims.

What is claimed is:

1. A bobbin comprising a tube having an end, a flange constituted of resilient material mounted on and encircling the tube at said end, said tube and flange having abutting surfaces and forming a substantially continuous uninterrupted surface for the accommodation of yarn to be wound on the bobbin, said tube having an annular recess of given radial dimension defining a seat for said flange, the abutting surface of the tube being a bounding surface of the recess, said tube including an upturned end portion at the remote end of said tube applied against the flange to urge the same in a direction away from the end of the tube to cause said abutting surfaces to be forced into contact with one another, said flange having an inner peripheral surface in facing relation with the tube in said seat, said flange having an annular groove opening into said inner peripheral surface, said groove having a depth greater than the radial extent of the recess and providing axial elasticity for said flange for the development of elastic pre-stress between the abutting surfaces with the upturned end portion applied against the flange.

2. A bobbin as claimed in claim 1 further comprising an elastic ring accommodated in the groove of the flange.

3. A bobbin comprising a tube having an end, a flange constituted of resilient material encircling the tube at said end, said tube having an annular recess of determinable radial extent constituting a seat in which is accommodated said flange, said flange having an inner peripheral surface facing said seat, said flange having opposite surfaces, said recess being bounded by a surface remote from the end of the tube, which surface is in contact with the surface of the flange which faces away from said end of the tube, said flange being provided with an annular groove which opens into the inner peripheral surface of the flange, said groove having a depth greater than the radial extent of the recess and providing axial elasticity for the flange at the level of said groove, said tube including an upturned portion. at the extreme end of the tube in engagement with the other of the surfaces of the flange and applying an adjustable force against the flange to elastically deform the peripheral groove therein which thereby develops a prescribed elastic pre-stress condition in the flange urging the surface thereof which faces away from the end of the tube against the aforementioned surface of the tube which bounds said recess whereby the latter surfaces are forced into contact with one another with a predetermined magnitude of prestress.

4. A bobbin as claimed in claim 3 com-prising an elastic ring in said groove also being subjected to elastic deformation by the application of force to the flange by the upturned portion of the tube.

5. A bobbin as claimed in claim 3, wherein said groove has a cross-section which is inclined outwardly in a direction towards the end of the tube.

6. A bobbin as claimed in claim 3, wherein said bounding surface of the recess is inclined radially outwards in 7 1 direction towards the end of the tube, the surface of :he flange which is in contact with the latter surface extending substantially perpendicular to the axis of the tube.

7. A bobbin as claimed in claim 3, wherein said flange has a conical recess in said other surface thereof for receiving the upturned portion of the tube.

*8. A bobbin comprising a tube having an end and an internal bore of determinable diameter, a flange coupled to said tube at said end and having a surface in contact with a surface of the tube to form a joint thereat, means elastically acting on the flange to develop an elastic prestress therein which urges the surfaces of the tube and the flange at said joint into tight engagement to provide a substantially continuous surface at said joint and prevent opening thereof, an insert in said tube at said end closing the same, said insert comprising an assembly of an elastic outer plug and inner bush inserted in said plug, said outer plug comprising an outer cylindrical wall, an inner cylindrical hub coaxially within the wall in spaced relation, and a plurality of ribs extending between the hub and the wall, said ribs extending tangentially from the hub to the wall and providing substantial radial elasticity between the wall and the hub.

9. A bobbin as claimed in claim 8 wherein said outer cylindrical wall of the plug has a groove conforming to the shape of the seat for accommodating the same, said wall in a region outside of said groove having an outer diameter exceeding the inner diameter of the tube at said seat.

10. A bobbin as claimed in claim 8 wherein said tube has an end opposite the first said end and a second flange identical to the first coupled to the tube at the second end, there being provided a second insert in said tube at said second end, the bobbin further comprising an insert tube member supported Within the tube and positioned between the inserts at the opposite ends.

References Cited by the Examiner UNITED STATES PATENTS 634,738 10/1899 Sampson 2421 18.6 1,150,011 8/1915 Barker 242-1186 1,395,038 10/1921 Clinton 242-118.61 1,862,694 6/1932 McC-onnel et al. 242-1 18.61 X 3,013,378 12/1961 Newton 242-1l8.6 X 3,081,960 3/1963 Howe 24273 X FOREIGN PATENTS 558,613 5/1923 France.

FRANK J. COHEN, Primary Examiner.

GEORGE F. MAUTZ, Examiner.

Claims (1)

1. A BOBBIN COMPRISING A TUBE HAVING AN END, A FLANGE CONSTITUTED OF RESILIENT MATERIAL MOUNTED ON AND ENCIRCLING THE TUBE AT SAID END, SAID TUBE AND FLANGE HAVING ABUTTING SURFACES AND FORMING A SUBSTANTIALLY CONTINUOUS UNINTERRUPTED SURFACE FOR THE ACCOMMODATION OF YARN TO BE WOUND ON THE BOBBIN, SAID TUBE HAVING AN ANNULAR RECESS OF GIVEN RADIAL DIMENSION DEFINING A SEAT FOR SAID FLANGE, THE ABUTTING SURFACE OF THE TUBE BEING A BOUNDING SURFACE OF THE RECESS, SAID TUBE INCLUDING AN UPTURNED END PORTION AT THE REMOTE END OF SAID TUBE APPLIED AGAINST THE FLANGE TO URGE THE SAME IN A DIRECTION AWAY FROM THE END OF THE TUBE TO CAUSE SAID ABUTTING SURFACES TO BE FORCED INTO CONTACT WITH ONE ANOTHER, SAID FLANGE HAVING AN INNER PERIPHERAL SURFACE IN FACING RELATION WITH THE TUBE IN SAID SEAT, SAID FLANGE HAVING AN ANNULAR GROOVE OPENING INTO SAID INNER PERIPHERAL SURFACE, SAID GROOVE HAVING A DEPTH GREATER THAN THE RADIAL EXTENT OF THE RECESS AND PROVIDING AXIAL ELASTICITY FOR SAID FLANGE FOR THE DEVELOPMENT OF ELASTIC PRE-STRESS BETWEEN THE ABUTTING SURFACES WITH THE UPTURNED END PORTION APPLIED AGAINST THE FLANGE.

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