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(11) | EP 0 095 445 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Improved cylinder with rotating sleeve to prevent twisting on circular knitting machines |
| (57) improved cylinder (10) with rotating sleeve to prevent twisting on circular knitting
machines, and advantageously on circular machines for stockings, whereby said cylinder
(10) comprises an inner sleeve (19) rotating in cooperation with the part of the cylinder
(10) which knits, and whereby said sleeve (19) is supported at its upper end by the
sinker ring (12) and said sinker ring (12) in its turn is supported by the needle
cylinder (11), and whereby means for the vertical adjustment of the sinker ring (12)
and also means able to hinder the vertical raising of said ring (12) are envisaged. |
[0001] This invention concerns an improved cylinder with rotat-. ing sleeve to prevent twisting on circular knitting machines. and, in particular,on circular machines for stockings.
[0002] It is known that, above all on circular machines for stockings, the fabric produced becomes twisted during the. processing, that is to say, the rows of stitches formed leng- .thwise take on a spiral development, which is caused partly . .by the twisting of the yarn, partly by the knitting action of .the needles and partly by the friction applied to the fabric. .itself by the inner portion of the cylinder through which the .formed fabric passes.
[0003] Said friction is developed because in the known art .the part of the cylinder which does the knitting and which .consists of the needle cylinder and sinker ring rotates and . .takes with it the fabric formed, whereas the inner part of .the cylinder comprising the sinker cams and the elements bear- .ing said cams is stationary and is in contact with the formed fabric through an inner bush solidly fixed to said bearingelements, the fabric sliding on said inner bush.
[0004] Said friction is considerably accentuated when the ma- . chine employs a system to pull the fabric which envisages elements cooperating with said stationary bush, such as a pair of scoop elements rotating substantially in step with the cylinder and gifted with an alternating axial motion which brings the periphery of each scoop element alternately. into contact with the fabric, which is interposed between the funnel-shaped portion of said stationary bush and the periphery of said scoop elements, whereby said fabric is thrust axially by the scoop elements, which thus produce the desired action.
[0005] The twisting of the fabric due to the aforesaid factors. is corrected by a pressing operation thereafter; the greater. the twisting of the fabric, the more carefully the pressing . operation has to be performed.
[0006] The main purpose of our invention is to embody an improved cylinder for circular knitting machines which is especially suitable for machines making hosiery and which has const-. ructional lay-outs that enable the unfavourable friction be-. tween the fabric and the inner part oi the cylinder to be eliminated so as to lessen considerably the times employed in the pressing operation.
[0007] Our invention also proposes further improvements concern ning the part of the cylinder which carries out the knitting. work.
[0008] At the present time, if the sinker nib or butt is broken or the sinkers have to be changed, the work in replacing one. or more sinkers is relatively delicate and burdensome in that there is a risk that the sinker ring may be displaced from its correct alignment on the cylinder.
[0009] Furthermore, with the cylinders now existing there is a. possibility that the intrinsic dust of the yarn and dirt in . general may be introduced between the sinker ring and the upper sinker cams, thereby leading to shortcomings in the working of the machine.
[0010] Our invention aims to eliminate or lessen the aforesaid. problems and shortcomings by adopting specific means and suitable technical lay-outs.
[0011] The invention is therefore embodied in an improved cylinder with a rotating sleeve to prevent twisting on circular . knitting machines, and advantageously on circular machines for stockings, said cylinder being characterized by compris-. sing an inner sleeve rotating in cooperation with the part of the cylinder that performs the knitting, whereby said sleeve. cooperates at its upper end with the sinker ring through supporting means, and whereby supporting means and means for the vertical setting of the sinker ring are envisaged on the need- ,le cylinder, and whereby means are included which can hinder. .the vertical displacement of said sinker ring from its position of alignment on the needle cylinder.
[0012] The invention visualises supporting means and means for .the coupling of said inner sleeve to the sinker ring, said- means consisting respectively of a supporting surface obtain- .ed by making an annular cutaway portion on the upper surface .of the sinker ring, and of an 0-ring located between the sink- .er ring and the edge of the inner rotating sleeve which faces .said sinker ring.
[0013] . In the preferential embodiment of the invention said 0- .ring has the twofold task of setting and keeping in rotation .said inner sleeve during the operation of the knitting portion .of the cylinder and also, in cooperation with the surface 23,. of preventing the entry of dust and dirt between the sinker - .ring and the inner rotating sleeve.
[0014] Moreover, according to the invention the sinker ring is . .upheld not by fixed organs such as the cams of the sinkers, .but by the needle cylinder rotating with and solidly fixed to .said sinker ring, which is adjusted vertically by shin means. .which can be inserted between the sinker ring and the surface .of the cylinder that supports said sinker ring.
[0015] Furthermore, in the preferential embodiment of the inven- .tion the means able to hinder the vertical displacement of .the sinker ring when one or more sinkers are being changed .consist of a prong cooperating with a circumferential groove. .made in the stationary tubular element..of the cylinder, said .prong being envisaged at the lower end of the tongue which is .solidly fixed to the sinker ring and is located between the . .needle cylinder and said sinker ring so as to set the latter. .in rotation.
[0016] According to a variant of the invention the inner rotat- .ing sleeve is not engaged with the knitting portion of the cylinder but rotates at an adjustable speed of rotation lower .or higher than or the same as the speed of said knitting port- .ion owing to the action of drive means cooperating with the .lower part of the rotating sleeve stretching along the lower .cylinder of the machine.
[0017] According to said variant it is possible to control ad-. .vantageously, to suit specific requirements, the friction de- .veloped between the rotating sleeve and the fabric owing to .the different'speed of rotation of said sleeve as compared to .the knitting portion of the cylinder and to the system for .pulling the fabric.
[0018] We shall give hereinafter the description of the impro-. .ved cylinder according to the invention with the help of the. .attached table, wherein:- .
.Fig.1 shows the preferential embodiment of the cylinder cooperating with a pulling system of scoop elements of. the type described hereinbefore; .
Fig.1a shows a detail of the zone of the coupling of the ro-, tating sleeve to the sinker ring; .
Fig.2 shows a variant of the invention.
[0019] With reference to the Table, the improved cylinder 10 of the invention has a knitting portion consisting of the outer- cylinder 11 bearing the needles and of the ring 12 bearing . the sinkers, and a stationary portion consisting of a central tubular element 13, an inner tube 14 coaxial with said tubular element 13, the upper 15 and lower 16 cams of the sinkers; said cams 15 and 16 being lodged in a seating formed by the upper end 17 of said central tubular element 13, and of an .inner bush 18 screwed onto said tube 14.
[0020] According to the invention an inner sleeve 19 is envisa- .ged which is coaxial with the cylinder 10 and rotates substan- .tially in step with the knitting portion of the cylinder 10; .said inner sleeve 19 cooperates at its upper end with the sin- .ker ring 12 and stretches downwards so as to cover the inner- .bush 18 fully.
[0021] . Said sleeve 19 has a substantially flat portion 20 along- .side the sinker ring 12, a middle funnel-shaped portion 21 .and a lower tubular portion 22.
[0022] Said inner rotating sleeve 19 is upheld on a supporting. .surface 23 obtained by making an annular cutaway part on the .inner portion of the surface of the sinker ring 12.
[0023] . In the preferential embodiment of the invention shown in .Fig.1 and according to the detail of Fig.1a an 0-ring 24 is . .visualized as being lodged in a circumferential groove 25 on .the upper edge of the sleeve 19 facing the sinker ring 12; . .when the rotating sleeve 19 is being fitted, said 0-ring 24 is forced against the sinker ring 12, which is provided with .a connecting surface 12' with a slight taper that tends to .keep the rotating sleeve 19 anchored to the sinker ring 12 be- .low an'inducting bevel 12" made to assist installation. The .mechanical union of said two elements is thus insured.
[0024] Moreover, the O-ring 24 has the twofold task of anchoring the inner sleeve 19 solidly to the sinker ring 12 and, in cooperation with the surface 23, of preventing the entry of . dust or dirt which may cause difficulties during working, between said two elements 12-19.
[0025] The tubular portion 22 of said inner rotating sleeve 19. has on its periphery the sliding surfaces 26 cooperating with the inner surface 27 of the bush 18 so as to provide further. assurance of the guiding and alignment of the sleeve 19.
[0026] According to the-invention the employment of the rotat-. ing sleeve 19 entails full elimination of unfavourable friction of the fabric against the cylinder 10 and thereby the elimination of the permanent twisting of the fabric caused by said friction.
[0027] This is particularly advantageous whenever the machine . uses a fabric-pulling system which accentuates the friction . of the fabric against the cylinder 10, as shown, for instance, in the attached table wherein the pulling of the fabric is obtained with a pair of scoop elements 28 envisaged within the. upper cylinder 29 and rotating substantially in step with the cylinder 10 and gifted with an alternating axial motion . out of phase as between one scoop element 28 and the other, . whereby said motion brings the periphery 30 of each scoop element 28 alternately into contact with the fabric moving within the cylinder 10, thus producing the desired pulling action on the fabric cooperating with the knitting portion of the cylinder.
[0028] In this case the pressure exerted by the scoop elements. .28 on the rotating sleeve 19 is discharged on the surface 23. supporting the rotating sleeve 19 and envisaged on the sinker .ring,thus cooperating helpfully in keeping said rotating sle- .eve 19 in rotation.
[0030] 12 is supported, not by the sinker cams 16, but by the needle cylinder 11 through interchangeable shims 31 placed between the needle cylinder 11 and the surface of the sinker ring 12. supporting the same on the needle cylinder 11, whereby said shims 31 enable the vertical position of said sinker ring 12. to be adjusted.
[0031] The sustaining of the sinker ring 12 by the needle cylinder 11 makes it possible to prevent the weight of the sinker. ring 12 itself and the pressure produced by the pulling action from burdening the curved surfaces of the lower sinker .cams 16 and thereby to avoid shortcomings during rotation of. .the sinker ring 12 in relation to the stationary sinker cams
[0032] According to the invention a further improvement of the. .cylinder 10 is intended to facilitate the replacement or ex-. change of one or more sinkers and consists in embodying a ton- .gue 32 to couple the sinker ring 12 to the needle cylinder 11, whereby said tongue 32 is solidly fixed to the sinker ring 12 .and has at its lower end a prong 33 cooperating with a circumferential groove 34 envisaged on the upper end 17 of the cen- .tral tubular element 13.
[0033] When one or more sinkers are being replaced and the butt .of the sinker has to be able to pass, it is necessary to un-. .screw the tube 14 that secures the inner bush 18 and then to .raise the upper sinker cam 15.
[0034] At the present time the machine operator has to devote . .much care and attention to said operation since there is a .risk that the sinker ring 12, which is only resting on the .needle cylinder 11, will rise together with the inner bush 18 .and upper cams 15, thereby hindering the removal of the sinker.
[0035] But in the case of the cylinder 10 of our invention this .risk does not exist since the prong 33 of the tongue 32,which is secured to the sinker ring 12 with screw fixture means, 35,. prevents this rising action as it is engaged in the circumferential groove 34 envisaged on the tubular element 13.
[0036] According to a variant of the invention the inner rotating sleeve 19 is not engaged with the knitting part of the a cylinder 10 but rotates at/speed of rotation which may be the same as or higher or lower than that of said knitting part . and which can be regulated by actuation means 36 cooperating. with the lower part of the rotating sleeve 19 stretching along the lower cylinder of the machine, as shown in the non-restric- .tive example of Fig.2.
[0037] According to said variant it is thus possible to control, .so as to suit the specific requirements, the friction developed between the rotating sleeve 19 and the fabric owing to the difference between the speed of rotation of said sleeve 19 . .and the speed of rotation of the knitting part of the cylin-. .der and of the system that pulls the fabric.
[0038] . In this way it is possible to impart to the fabric a twi- .sting which can cancel or be added to the twisting caused by. the torsion of the yarn itself and by the knitting action of. .the needles, depending on whether it is wished to eliminate .the twisting of the fabric wholly or to accentuate said twist- .ing for reasons tied to the fabric design to be obtained.
[0039] We have described herein a preferential embodiment of .the invention and also a variant, but further variants are .possible within the scope of the Claims which follow.
I N D E X
[0040]
10. Improved cylinder
11. Needle cylinder
12. Sinker ring
13. Central tubular element
14. Tube to secure inner bush
15. Upper sinker cams
16. Lower sinker cams
17. Upper end of central tubular element
18. Inner bush
19. Inner rotating sleeve
20. Flat portion of inner sleeve
21. Funnel-shaped portion of inner sleeve
22. Tubular portion of inner sleeve
23. Surface supporting the inner sleeve
24. 0-ring
25. Circumferential groove to lodge 0-ring
26. Alignment surfaces of rotating sleeve
27. Surface of inner bush
28. Scoop elements to pull the fabric
29. Upper cylinder
30. Periphery of scoop elements
31. Interchangeable shims
32. Coupling tongue
33. Prong of coupling tongue
34. Circumferential groove to lodge the prong
35. Means to secure the tongue
36. Means to drive the rotating sleeve.
1. Improved cylinder (10) with rotating sleeve to prevent twisting on circular knitting
machines, and advantageously on circular machines for stockings, characterized by
comprising. an inner sleeve (19) rotating in cooperation with the part of the cylinder
(10) that knits, whereby said sleeve (19) is sustained at its upper end by the sinker
ring (12), which in its turn is borne by the needle cylinder (11), and whereby means.
for the vertical setting of the sinker ring (12) and also means able to hinder the
vertical raising of said sinker ring . (12) are envisaged.
2. Improved cylinder (10) with rotating sleeve to prevent twisting as in Claim 1,
characterized by the fact that said . sleeve (19) is solidly fixed to the part of
the cylinder (10) that knits, and rotates in step with said knitting part,whereby
means to couple together the sinker ring (12) and said sleeve (19) are visualised.
3. Improved cylinder (10) with rotating sleeve to prevent twisting as in Claims 1
and 2, characterized by the fact that said coupling means consist of an 0-ring (24)
located between the sinker ring (12) and the edge of the inner rotating sle-. .eve
(19) which faces said sinker ring (12).
4. Improved cylinder (10) with rotating sleeve to prevent .twisting as in Claim 1,
characterized by the fact that the in- .ner rotating sleeve (19) is engaged with the
knitting part of .the cylinder (10) and rotates at a speed the same as or higher .or
lower than that of said knitting part, said speed being .regulated by drive means
(36) cooperating with the lower part of the rotating sleeve (19) stretching along
the lower cylin- .der (10) of the machine.
5. Improved cylinder (10) with rotating sleeve to prevent .twisting as in Claim 1
and in one or another of the,Claims thereafter, characterized by the fact that the
rotating sleeve (19) is supported by the sinker ring (12)'by.means of a sup-. porting surface (23) obtained
by making an annular cutaway portion on the upper surface of said sinker ring (12).
6. Improved cylinder (10) with rotating sleeve to prevent twisting as in Claim 1 and
in one or another of the Claims . thereafter, characterized by the fact that the means
for ver- .tical adjustment of the sinker ring (12) consist of interchan- .geable shims
means (31) placed between the needle cylinder .(11) and the surface of the sinker ring (12) which rests on . .said needle cylinder (11).
7. Improved cylinder (10) with rotating sleeve to prevent .twisting as in Claim 1
and in one or another of the Claims . .thereafter, characterized by the fact that
the means able to. hinder the vertical raising of the sinker ring (12) consist . .of
a prong (33) cooperating with a circumferential groove (34) .made in the stationary
tubular element (13) of the cylinder . .(10), whereby said prong (33) is envisaged
as being at the .lower end of the tongue (32) solidly secured to the sinker .ring
(12) and located between the needle cylinder (11) and .said sinker ring (12) so as
to set the latter (12) in rota- . .tion.