A adjustable bobbin holder
The present invention relates to a bobbin holder/ primarily for yarn bobbins in weaving mills and other textile factories, comprising a holder shaft with associated holder means adapted so as to be adjustable for enabling the bobbin holder to receive bobbin tubes of various inner diameters and of various shapes, viz. of cylindrical and conical shapes, respectivel .
In weaving mills and hosiery works yarn bobbins are used, which are wound on core tubes that may be either cylindrical or conical, and particularly in weaving mills, e.f in carpet factories, in which bobbins and bobbin holders are used in thousands, it is practical that the bobbin holders be usable for receiving the different types of bobbins as produced by the yarn factories, without having to be considerably modi¬ fied or changed.
According to the invention there is provided a bobbin holder which may receive and hold both cylindrical and conical bobbins by a simple insertion onto the bobbin holder, with¬ out any kind of adjustment thereof. From US-A-3,744,735 and DE-B-2225555 it is known that a bobbin holder may be adjusted or manipulated so as to suit respective different bobbin tubes of cylindrical or conical shape, but such adaptions will require a manual effort for modifying the bobbin holders generally by each shift from one type of bobbin to another.
For the invention it is decisive that for the mounting of the various types of bobbins on the bobbin holders nothing should be done but the mere insertion of the bobbins onto the holders, i.e. the bobbin holders should allow for an easy insertion of the bobbins irrespective of the size or shape thereof, of course within certain limits of variation, for achieving a reasonably centered holding of the bobbins on the bobbin holders, just as the bobbin core tubes, upon the
bobbins being emptied, should be correspondingly immediately withdrawable from the holders.
The bobbin holder according to the invention comprises a holder shaft and two circular rows of resilient finger ele¬ ments adjacent the front end and the rear end of the holder shaft, respectively, these elements projecting outwardly and rearwardly such that they will holdingly engage with the inside of the bobbin tube inserted over the holder; the fin¬ ger elements of the two rows operate independently of each other, so they can adapt themselves to both cylindrical and conical bobbin tubes. For a conical bobbin tube the foremost finger elements will just be forced inwardly in a progressive manner during the insertion of the bobbin tube onto the holder.
In a preferred embodiment of the invention the foremost fin¬ ger elements project further rearwardly and inwardly from their outer area of engagement with the bobbin tube, whereby the elements engage the holder shaft adjacent both of their ends; they are secured to the shaft at one of their ends and to a common slide ring member at their other ends, whereby the elements are bound to be deformed in a uniform manner, such that they will actively center the bobbin relative the holder shaft. Such a centering is particularly important when the bobbin holder is arranged in a rotatable manner for lateral unwinding of the yarn.
Preferably it should be the front ends of the finger elements which are fixed to the shaft, close to the front end thereof, while the slide ring is arranged approximately midways on the shaft; hereby it is ensured that the total thickness of the front end of the holder can be kept as small as possible, which is desirable because many standard conical bobbin tubes are quite narrow at their front ends. At the middle of the shaft there will be more free space available for the pro¬ vision of the slide ring.
The same slide ring may conveniently be used as a basis for the rear circular row of finger elements.
In the following the invention is described in more detail with reference to the drawing in which:-
Fig. 1 is a perspective view of a bobbin holder according to the invention.
Fig. 2 is a longitudinal sectional view thereof.
Fig. 3 is a side view of the holder holding a cylindrical bobbin, and
Fig. 4 is a similar view of the holder holding a conical bobbin.
The holder shown in Figs. 1 and 2 comprises a central shaft rod 2 having a rear extension 4 permitting it to be rigidly mounted in a holding socket 6 on a carrier member 8, which may be a fixed beam provided with several sockets 6 for a number of bobbin holders. The shaft rod 2,4 is fixable in the socket 6 by means of a clamping screw 10.
A tubular shaft 12 is mounted on the shaft rod 2 by inter¬ mediate of a front bush 14 and a rear bush 16, such that the shaft 12 is freely rotatable on the rod 2. At the rear end of the shaft 12 is mounted a sleeve member 18, which is co-rotatable with the shaft 12 and has a rear collar portion 20. A radial clamping screw 22 is mounted through the sleeve 18 and through a threaded hole in the shaft 12 so as to step on the outside of the rear bush 16, whereby the latter is deformable to press more or less against the surface of the shaft rod 2 to thereby provide for an adjustable friction braking of the rotation of the shaft 12. The bush 16 may be axially slotted to facilitate such an adjustment.
At the front end of the holder is mounted a front cap 24, which serves to cover and lock the front end portions 26 of
a number of finger elements 28 to the front end of the shaft 12. These elements each comprises a foremost inclined por¬ tion 30 projecting rearwardly and outwardly from the front end portion 26 to an outermost engagement portion 32 and a rear inclined portion 34, which extends from the engagement portion 32 rearwardly and inwardly to a ring member 36, which is slidingly held on the shaft 12. The finger elements 28 are secured to the ring member 36 by having rear end portions 38 received and locked in a recess 40 in the ring member 36.
The finger elements 28 are die cast plastic elements, which are shaped with integral hinge portions 42, 44 and 46 between the respective main portions 26, 30, 34 and 38, such that the portions 30 and 34 may be folded inwardly and outwardly in conjunction with an associated axial displacement of the ring member 36.
Between the rear side of the ring member 36 and the front end of the sleeve member 18 is inserted a compression spring 48 that will bias the ring member 36 towards the left, against an oppositely directed bias from the finger elements 28. The latter bias is rather weak, but sufficient to condition a holding of the ring member 36 in a well defined position when the holder is not carrying any bobbin.
The front end portions 26 of the finger elements are provided with inwardly directed protrusions 50, which are received in respective radial holes in the front end of the tubular shaft 12 and the cover cap 24 fits closely about or against the outer sides of these end portions 26 so as to stabilize this holding engagement. The cap 24 is secured in its posi¬ tion by having an inner annular rib 52 which is received in cooperating cross grooves in the outsides of the end portions 26.
The ring member 36 is made of plastic and is integrally pro¬ vided with a circular row of rearwardly and outwardly pro-
jecting finger members 54 acting as spring rods, which can be bent resiliently inwardly.
When a cylindrical bobbin 56, Fig. 3, is inserted on the holder the inside of the bobbin tube core 58 will hit the foremost inclined finger element portions 30 and cause these to be swung inwardly about the hinge portions 42 until the bobbin tube can slip over the outer engagement portions 32 of the elements 28. Hereby also the element portions 34 will be swung inwardly, and as a result the ring member 36 will be displaced rearwardly, against the action of the compres¬ sion spring 48, i.e. this spring will now urge or bias the ring member 36 rather strongly towards the left, whereby the finger elements 28 tend to be folded outwardly and thus to create a substantial holding force between the engagement portions 32 and the inside of the bobbin core tube 58. Upon further insertion of the bobbin the leading end thereof will be pushed over the rear finger members 54, which will yield inwardly and hold the rear end of the bobbin.
The outer hinge portions 44 are provided by a reduced material thickness at a transverse recess, which forms sharp corners 33 with the outside of the element portions 30 and 34. These corners will increase the holding effect on the bobbin, but of course they do not prevent the bobbin from being readily insertable on and retractable from the holder.
It will be appreciated that the holder will readily accept also conical bobbins, as illustrated in Fig. 4. The two sets of finger elements 28 and 54 act independently of each other, so the conical shape will not change the operation conditions of the holder.
Because the opposite ends of the finger elements 28 are col¬ lectively secured to the shaft 12 and to the ring member 36, respectively, the elements will be bound to behave uniformly
or symmetrically with respect to their being folded inwardly and outwardly, i.e. they will cause the bobbin to be centered even if the resiliency of the various elements is not entirely uniform.
The spring 48 could be avoided if the finger elements 28 are made with an inherent resiliency seeking to fold the elements outwardly, in which case a stop should be provided for the displacement of the bushing 36 towards the left.
The finger elements 28 are preferably produced as a single casting, viz. as radial protrusions from a central bushing 60. Prior to their mounting they are folded forwardly over the bushing and then their rear ends 38 together with the bushing 60 are inserted in the recess 40 of the ring member 36. The insert can be secured by means of a radial screw and/or by a rib and groove engagement 62 between the inside of the ring member 36 and the outsides of the end portions 38.