CA1043069A - Construction of pendulum arm type high sensitivity self-aligning weighting arm - Google Patents

Abstract

ABSTRACT
A pendulum arm type high sensitivity self-aligning weight-ing arm includes a press assembly for pressing a driven roller body against a driving body such as a roller body or a belt body, One end of the press assembly which has the function of holding and pressing the driven body and which provides a fulcrum for the weighting arm is pivotally supported in such a manner as to be capable of executing pitching, yawing and rolling motions, while the other end holds a rotatable roll shaft for the driven body.
The weighting arm has a rolling-contact bearing element which is positioned by a cap in a region of contact between the weighting arm and the press assembly, which uses a compression spring, compressed air or other fluid pressure for pressing the weighting arm.

Description

~)43C~69 The present invention relates to a self-aligning type weighting arm for use with a top-roller holding and pressing device which can be used for forming a nip for dra~t operation in textile machines including drawing frames, flyer frames and spinning frames.
The following description will refer to the accompanying drawings, whereinO
Figure 1 is a side view of a Gonventional adjusting type guide arm;

Figure 2 is a plan view of said arm;

Figure 3 (sheet 2) is a graph showing deviated - conditions according to a self-aligning device utilizing the guide arm shown in Figures 1 and 2;
Figure 4 (sheet 1) A and B, which appear on the same sheet as Figures 1 and 2, show a conventional pendulum type guide arm;
Figure S is a graph showing the frequency dis-tribution of parallelism of back top rollers in a conventional device;
: 20 Figure 6 is a graph showing the frequency dis-tribution of parallelism of front top rollers;
FigurP 7, A and B, which appear on the third sheet of drawings, show a conventional fixed type guide arm;
Figures 8, 9 and 10 show a conventional adjustable type guide arm, Figures 11 and 12 (sheet 3~ show concrete examples of the adjustable type;
Figure 13, A and B, (sheet 4) which appear on the same sheet as Figures 8 and 9, are views ex~lanatory of self-aligning action;

Figure 14 (sheet 4) i~ a view explanatory of the main point o~ dynamical consideration of said action;

B

3q~
Figure 15, A and B~ is an imaginary view of a convention-al weighting arm assembly;
Figure 16, A, B and C, is a view explanatory of operating difficulties;
Figure 17, A9 B and C, and Figure 18, A and B, show embodLments incorporating the basic nature of the present in-vention;
Figures 19 through 24 are views showing other examples of the pre ent invention; and Figure ?5 is a table showing Lmprovement percentages under various items.
In general, a pendulum arm type weighting arm having a self-aligning action which is in wide use3 as shown in Figures 1 and 2~ comprises a weighting arm A, a guide arm case B, a guide arm pin C, a driving body D(having a curved or a plane surface), driven rollers RJ a driven roller shaft G, and a press body SO
Usually9 the draft section of a textile machine comprises : two or more pairs of parallel-disposed assemblies described above3 and in each such pair the driven top roller R is xotated as pressed against the driving bottom roller D while maintaining a cyli~drical contact relation therewith and forming a pressure nip which may have various forms~ including point~ line and surface contact~ clepending upon the quality of p~rallelism of the axes o the top and bottom rollersO For the textile machine draft section, highly stabilized surface contact is an essential prerequisite for Improved yarn quality~ More particularly, if the parallelism between the axes of the top and bottom rollers ~ and D i~ LmpairedJ this causes an unstable change in their ~436~6~
condition of contact, bringing them into a point or line contact condition, which means that a stable pressure nip cannot by main-tained and hence it is difficult to obtain a smooth and skable draft ac~ion, with the result that there is a direct adverse effect on the quality of the product. 'rherefore, maintaining the parallelism of the axes of the bottom and top rollers D and R
has been an indispensable condition for the draft section of textile machines. Conventionally9 the measures taken to achieve this condition have been to maximize the degree of accuracy of the guide arm A and weighting arm, to make adjustments during assembly, or to resort to self-alignmentO It is under always-parallel conditions that the rollers continue to form a roller nip with a uniform pressure distribution over the entire area of contact while executing pr~ssure contact rotationO This de-vice has a tendency to produce an unstable condition as it is ~ubjected to the influence of a complex motion such as yawing, rolling and pitching due to the arrangement of the weighting anm Ao Particularly in the ca~e of Figure 1 wherein the driven roller R and the driving roller D contact each other along a cylindrical surface, depending upon the quality of parallelism of their axes, their contact condition presents various forms, producing a very unstable nip in connection with pressingO
In brief, the draft section requires a stable and secure nipO Further, it is important to maintain a strong nip condition uniformly distributed over the entire width of the contact regionO
More particularly, if the parallelism between the axe~ of the top and bottom rollers R and D is impaired, this produces an un-stable change in the nip condition o~ the rollers, w.ith the ~43~6~31 pres~ure contact condition changing its linear form into one re~
sembling a point, thereby making it difficult to obtain a unformly pressed nip condition stabilized widthwise of the rollersO
Figure 3 shows deviated conditions associated with a self-aligning mechanism corresponding to Figure 1~ wherein a designates a - normal condition and b and c designate abnormal conditions de--viated to either side. When measured at a job site, it is ~ound that in most cases either a or b predominates. The maintenance of the parallelism of the axes of the driven roller and the driv-ing bsdy is a subject of utmost importanceO No sufficient approachto meet this condition has been establishedO Heretofore, there has been no choice but to maxLmize the degree of accuracy of the components of the guide arm and the weighting arm, to repair or adjust them during assembly while taking much time, or to resort to a ~el~-aligning mechanism o~ the convention~l type though this is not very satisfactoryO These approaches, however, have their lLmitationsO In order to meet the needs of the market, it is necessary to no longer rely on the con~entional ~systems which are at a deadlock and instead to invent a novel weighting arm con-struction of high sensitivityO Such demand has led to varioustypes of weighting constructionsO
The weighting anms actually employed at job sites may be classified into the following three typesO
SELF-CE~TERING TYPE ~PE~DULUM TYPE) This type, as shown in Figures 4A and 4B, is based on the principle of employing a pivot construction with the axis of the swing motion of a conventional pendulum type guide arm 3 located at a pin 6, whereby the guide arm is supported for rotation in the vertical and horizontal direction or yawing directionJ wherein a ~ 43~9 top roller 2 is rotated by a bo~tom roller 1, ther~by automatical-ly adj usting the parallelism of the top roller 2 with resp~ct to the bottom roller 20 The numeral 4 designates a spring; 5, a guide arm case; and 7 designates the support for the arm. Thus, this ype is based on the principle ~f the pendulum found in the centrally directed restoration action of two freely rotatable wheels in the case where said wheels are symmetrically arranged while a pendulum arm holding their shaft at its midpoint is dis-posed at right angles with the shaft and has its fulcrum located on an extension thereof The restoration action is based on the production o thrust due to alignment, but the influences of cumulative error due to various factors connected with manufac-ture including deviations in the spring, deviations in the guide arm case, deviations in the arm body, and errors in the holding part are noticeableO Particularly, the recent demand for in-creased weighting ha~ a marked tendency to amplify the effect of these sources of deviation because of the nature of the surface of contact between the top and bottom rollers. It is the second back roller and the following roller having a lower rpm that are particularly greatly subjected to said sources of errors. ~n these parts, the restoration force (a thrust force) is so small that it is insuEficient to accommodate said cumulative error.
Therefore, under these circumstances, when the part having the lower rpm has been remodelled into a pendulum form, this has resulted in interfering with the maintenance of the parallelism of the top roller relative to the bottom rollerO Further, in order to improve the draft performance of the draft section~ as is currently demanded~ it is indispensable to incraase the nip pressure. ~owever, the increase in the pressure on the top ~ 5 ~

1~L31369 roller in the cylinder-on-cylinder arrangement aggravates the errors in parallelism of the bottom and top rollersO Therefore, there is a limit to the increasedl pressure that can be applied with the arrangement using self-alignment based on the pendulum principle, and at present it is used beyond its limitO Parti-cularly in the second roller and the following roller having lower rpmO there is the drawback that this tendency toward de viation is pronouncedO (See Figures 5 and 6.) It has been proved that the adverse effect of relying on self-alignment on recent 10 flyer frames using low rpm and high weighting pressure leads to a lowering of the performance of the fiber draft section and that self-alignment has xeached its limit in improving quality~
As a countermeasure thereagain~t, a method is sometLmes employed in which a guide piece ~not shown) is attached to the guide arm for correction purposes, but it is practically impossible to maintain the required accuracy.
FIXED TYPE
This method is shown in Figures 7, A and Bo Figure 7, A~
shows a system not relying on self-alignmentJ wherein the part for holding the arbor of the top rollers pressed by a pressure is directly held at a right angle by a guide arm 3 in such a manner as to be capabl~e of two motions, yawing and rollingO In this system, the guide arm 3 itself is fixed to the arm body 90 De-9 ignated at 11 is a set screw and 12 is a spring-anchoring pinO
The arrangement shown in Figure 7, ~, resembles that shown in Figure 7J A. In order to prevent conc~mit~nt lowering of the pressure on the top roller due to frictional resistance at the part for holding the top roller to the guide arm, which is the drawback cf the type of arrangement of Figure 7, A, a guide arm ~ 3~i69 pin 10 is provided. As described above~ the fixed type is the type of guide arm used in heavy weighting systems when it has been attempted to eliminate the drawbacks of the pendulum system~
and in recent years there has been an increased tendency to use arrangements belonging to this type. It is impossibla to obtain satisfactory results unless the arm body is at a true right angle with the bottom roller and unless all the components of the guide arm have very high manufacturing accuracyO As in the pendulum system, cumulative error is produced, widening the range of scatter more than would be expected. In this case also, the cumulative error is not very different from that in the case of : the above-described pendulum systemO Though it is theoretically possible, as in the pendulum system, to maintain the parallelism of the top and bottom rollers, in practice it is very difficult.
Both the pendulum arm type and the fixed type have serious draw-backs with respect to self-alignment performance9 as described aboveO
This is fully endorsed by the following investigation results obtained at job sites. Thus, Figure 5 shows the degree of deviation of the back top roller in the pendulum arm system and in the fixed system~ and similarly Figure 6 shows the degree of deviation of the front top roller in said two s~stemsO In ea~h case, the data was obtained at large firms on the basis of a strict sasnpling methodO Considering this data, it is clearly seen that although the self-aligning type weighting arm is a little more advantageous, the deviation scatters over a wide range be-yond the allowable limits (range irrelevant to the occurrence of yarn unevenness)O For f irms which manage a very large number of groups~ it is no easy task to maintain the top roller in an ~43~
allowable conditionO
As a result, it can be said that basic investigation for a high sensitivity sel~-aligning construction having a maintenance-free capability is an urgent necessityO
The structural drawbacks of the weighting arm cannot ~e easily elLminated~ as described above, but this doeq not necessari-ly mean that there is no perfect arrangement. ~he adjustment type to be described below provides an improvement.
ADJUSTMEN~ TYPE
. 10 According to the adjustment type disclosed in Japanese Patent Application NoO 117330/72 (Patent Opening No. 72422/74), it is po~sible to elLminate the direct drawbacksO Figures 8-10 show an ex2mple of the adjustment system. According to this adjustment ~ystem9 in the draft section of a textile machinQ~ the top roller is fLxedly held by one end of the waighting anm (guide anm), the other end being supported in a pivot fashion to constitute the pendulum system, while separately from the guide anm, the guide arm ca-ee, or a separately fixed deviation-adjusting spherical element, is brought into spherical surface contact with a portion of the guide arm in a ~ree condition with respect to the guide arm so a~ to allow the yawing motion of the top roller to be adjusted and controlled, thereby maintaining the axis of the top roller parallel with the axis of the bottom roller and at the same time allowing the pitching motion and the rolling motion of the top roller to follow the bottom roller, thus ensuring that the bottom and top rollers will move in close and inseparable relation to one another. Thu~, this arrangement follows the principle of the pendulum system in that in the case where one end is supported in a pivot fashion in the guide arm, the top roller held by the holding part at the other end is free with respect to the three spatial coordinate axes, namely, in the X~ Y and Z axis directions, so that 3~D69 the top roller held hy the guide arm i~ pressed against the bottom roller in a complex relation of point~ line and sur~ce contact and in a manner which allows yawing, rolling and pitching motions thereof.
In this case~ the main factor in maintaining the paral-lelism of the top roller with respect to the bottom roller is the yawing motion of the top rollerO If the yawing moti~n of the top roller perfectly follows the bottom roller, all the conditions are balanced and the maintenance of parallelism of their axes is established, so that a stable surface contact nip can be obtained.
~n the contraxyJ if it is not able to ~ollow the bottom roller, all the other conditions lose their balance, making it impossible to achieve the intended objectO
If, therefore, a method is employed in which with the ro-tative axis of the top roller is held parallel to a reference axis based on the rota~ive axis of the ~ottom roller, then only he yawing motion of the guide arm is strictly controlled while allow-ing it to freely follow in the other directions, namely, with re-spect to the pitching and rolling motions and it then follows that the various conditions needed for the top roller weighking condition are satisfied, as described aboveO As long as this condition iæ
maintained, the condition of the nip for fleece having a given width becomes satisfactory and is stable for any heavy load. This relation holds perfectly for the pitching motion, but or the rolling motion3 t:heoretically it ~lightly in~luences the yawing motiona Howeverv its displacement is practically negligible with respect to a very small displacement of the order of bottom-roller deflection and it hardly becomes such a displacement as will have sufficient influence on the yawing motion to upset the parallelismO

_ g _ ~3~U69 The reason therefor iq shown in Figure 10~ Supposing a spherical surface accentricity-ad~uster to have a radius R (the amount of deviation ~), the amount: of displacement ~ in the yawing directio~ with respect to t:h~ angle e of the rolling motion at the point of contact between the spherical surface and the guide arm is expressed as follows:
~ = R (1 - cos ~ ) It is seen that ~ is nearly equal to zero for a infinitesimal di~placement of ~r In the adjustme~t system, various methods may be con-templated and in this connection Figures 8 and 9 show an example of the eccentric type and Figures 11 and 12 show examples of the adjusting pin type. Figure 11 shows the adjustment type using a lock nut No~ while Figure 121 A a~d Bs shuws a clamp type using a plate spring nl or nl', C shows the type using crLmping n3, D
shows a type u~ing an elastic body n2 such as rubber, and E shows the use of a ~ube n4 of a relativaly soft metal such as lead or copper combined with means for deforming the same to fix an ad-justing pin ~ at the middleO F shows one way for fixing the ad-justing pin, using an adhesive agent or solder n5~ Each type has been developed so that it allows adjustment when necessary. Thus, a suitable j ig is prepared for each type and is used when ~eces-sary to make adjustments, thereby eliminating difficulties due to the deviation of the top rollerO However, this system require~
skill and time in making adjustmants, ~o that it is difficult to put into practiceO Therefore, it is used by makers when a statistical method is applied to the weighting arm assembling operation to correct errorsO
At any rate~ these systems are based on a concept which 1~3~
almost ignores the self-aligning function of the pendulum arm, ignoring natural laws which could be advantageously utilized, and in practice they are not always convenient9 as described a~ve.
Thus, they cannot be called carefully thought-out measures.
However, su~ficient rnarits can be obtained by applying them to a wide gauge top roller or to very slowly rotating top rollers in-cluding the second top roller and the ~ollowing roller which are heavily loaded and whose rpm is very 14wo Further, thare has been an example in which a control system similar thereto is applied in the form of a guide arm control clip to the weighting arm in a flyer frame. ~ut this is nothi~g more than a makeshift means which is somewhat different in category from the above-described ad~ustment sys,tem. At any rate, compared with the weighting anm arrangements now in use~ this type of adjustment system provided an e~fective measure as considered from the point of view of manufacturing errors in the current mass-production system. Further~ a system which is based on the fixed type con-c~pt premises that the arm body is set always correctly as de-signed, as or example in the.saddle system prsduced by some leading firms, and this i9 far from satisfactory as evidenced by many actual examples thereof and by the actual results of maintenance thereof ~or yeaxs, and further by the fact that under present circumstances it form~ a source o noticeable complaints as to its qualityO
As is evident from the above, as along the weighting anm of the conventional system is employed, it is a task of extreme difficulty to maintain or control the parallelism of a vast number of top rollers which are operating in textile millsO
However, judging from the fact that the parallelism of the top 3~
roller R contributes much to lmproving the quality~ production efficiency and operational stabil:ity in the various subsequent proce~ses, it should be of vital :~portance to create a new technical arrangement which is capable of making effective use of the self aligning performance.
The description given so far has clarified the present condition concerning the circumstances and drawbacks of the weighting arms in the weighting arm units now in useO In particu-lar, the pendulum type arm which, though based on an ingenious idea, has not had its self-aligning performance fully developed because of its structural drawbacks, has been described by citing concrete examples. Now, the principle of the self-aligning per-formance of tbe pendulum anm will be considered by going back to its starting point.
Figure 13 is a view explanatory of the self-aligning actionO
As shown in Figure 13, the basic principle of the pendulum arm system is represented by Figures 13A and 13B~ When a driving surface D' is continuously moving in the direction of arrow YY', the press arm A is supported by a small-diameter pin I at a fulcrum 0 in a pivot fashion, and orthogonally holds the rotary shaft XX' of the driven roller R and is pressed ~ubstantially perpendicularly at a fixed point P on the guide arm by press meansO
In this arrangement, the press a~m A continues to maintain strict-ly the relation of JoJo ~XoXo under the condition of YY'l XX'.
This relationship is preserved irrespective of how many rollers as shown in Figure 13~ A and B are used, and remains unchanged as long a~ there is no disturbance from the outside.
The main points of a dynamic consideration of the rea~on thereor will now be de~cribed with reference to Figure 14. With 1~3(~6~
the driving surface D' continuously moving in the direction of the arrc~w (parallel with the ~' axis), consideration will be given to three basic attitudes a, b and c of the driven body R
with respect to its holding axis xx ' . For the movement of the driving surface D in the direction of the arrow parallel to the travel direction s~atum axis YY', the attituda a of the driven roller R show a condition in which it is at its datum axis original position where the relation YY'lxoxo'll B' holds;
attitude b shows a condition in which the roller is rightwardly 10 upwardly inclined at an angle e to the reference axis Xo~o', and attitude c shows a condition in which it is leftwardly upwardly inclined at an angle e to the datum axis XoXo ' O Therefore, in attitude a, the midpoint Q on the roller R is always positioned on the datum axis YY' extending through the pivot-like support point O and no angular displacement thereof takes place on ~he driving surface D'. On the other hand, the path described by the midpoint Q2 on the roller R2 is as shown by a straight line Y~ ~' while that for the roller Rl in c is represented by a straigh~ line yryx'. Since the roller R make~ line or sur:eace contact with the driving surface widthwise of the ro~l~r, it describes paths on the J~ 3~ and JR ~urface~, respectively.
That i~, in b and c, as shown in Figure 149 these paths are de-f ined by an angle of inclination e of the driven roller R to the datwll axis nr' ~ and in the pvsitional relation shown in Figure 14, both a and b follow path~ approaching the datu~ axi~
YY'O The speed s thereof expressed as follows:

. s = V sin e . O . . . O O (1) ~ ynamically, this relation can be directly replaced by a vector value having the direction of orce F~

~3(~69 As shown in Figure 15, A and BJ suppose a weighting anm construction wherein a support ann OQ having a length 1 and occupy-ing a fulcrum 0 on the datum axie YY' holds the roller shaft xx'0 AS long as the normal datwm positional relation xx'¦l XoXo~YY' is retained and thl- driving surface D' travels in the direction YY', the normal position is maintained per-manently since no vector is produced in the direction which dis-plac~s the axial direction XoXo'0 In Figure 159 A and BJ where the driving roller R is in the conditions of Rland R2, i~ is ~een that in the condition of Rl, a component vector Tl corresponding to the drive vector V is produced in the direction Gf axis X1X1 ' of the roller Rl. As a result of this thrust, a torque M in the restoration directio~
equal to Tl 1 with a center at the fulcrum 0 of the swing arm is produced to bring the weighting arm back in the directional con-forming to the datum axis YY' since the roll Rl is orthogonally supported by the swing arm of length 1.
M -- Tl lo o ~ o o o ~ o (2) At this time, the vector corresponding to the component force in the rotative axis direction xlxl' of the driven roller R1, iOe.
the thrust Tl produced in Rl is expressed as follows, Tl - V sin e 00...(3) Thus 9 it becomes evident that the thrust is a function of the angle of inclination ~ formed with the datum axis direction xOxO' of the driven roller Rl-From the equations (2) and (3~, M - 1 V sin ~ 00..00...00..0(4) From this equation it is seen that unless the angle of inclina-tion between the rotative axis direction xx' of the driven roller - 14 _ ~ ,i , , , ~ ~L3~
R and the datum axis direction XoXo' o~ the driven body with respect to the travel axis YY' of the driving body D' is stabiliz-ed such that e = o, the restoration torque M will not disappear.
Thus, if e = o, then M = o and the swing arm is stabilized at that position. In the case whPre the driven roll~r takes the disposition of R2, ~ only takes a minus sign and the various relations remain unrhangedO
The theory described above is applied to the pendulwm arm type weighting armO
Therefore, in this form, the swing support part 0 forming a fulcrum for the pendulum actio~ of a conventional weighting arm is in the form of a characteristic pivot-like support system and at the other end it correctly orthogonally holds the driven roller Ro Further, the means for presqing the weighting arm usually comprises a spring, e~g. a compression spring (coil spring of volute spring) or a plate spring of special shapeO The system shown in Figure l is a typical example of thi O In rare cases~ said means comprising a pres~ing device uses gas or llquid pressure, such as pneumatic or hydraulic pressure. Whiche~er system may be utilized, the present condition is thak it i3 arranged to act on the upper surface of the weighting arm or on a spring receiving part integral therewith, As long as a system corresponding to or similar to this kind of arrang~ment is employed, similar dr~wbacks invariably exist therein. Particularly in the typical example shown in Figure 1 using a spring, it can hardly be expected that a pressure vector or pressure distribution in the pressure contact region produced by the compression of the spring will be the theoretical, normal uniform distribution in the datum normal position of the ~3(~

weighting arm.
As described above, the existing pressing system~ whether a compression spring (coil spring or volute spring) or plate spring, actually have individually considerably scattered in-trinsic deviations~ and the direction of the spring pressure also tends to be scattered in a wide range with respect to the axial direction of the springO Thus, a technique for directing the direction of such spring correctly to the direction of the spring axis has not been establishedO Moreover, the tendency t~ward in-creasing the pressure in the weighting arm unit in accordancewith advances in ~extile technology including the rise of synthetic fiber blend spinning in addition to the increase of draft ratio and of productivity on the basis of operating stability and the guality-first precept5 has resulted in increasing the drawbacks of the existing weighting arm unitsO
Even if these deviations in spring pressure, etc. remain in a very small range, the secondary, balance-destroying action influenced by the buckling phenomenon found in compression springs, . and by the deviation of the axis of the pressing spring accompany-20 ing the angular displacement of the weighting arm A, continues tointerfere with the function peculiar to the pendulum arm of ad-justing the axis of the driven roller R to make i~ parallel with the rotative axis on the driving sideO This phenomenon may be considered to be shown in Figures 5 and 6 in terms of measured valuesO Figure 169 A, B and C, explains this interfering phenomenonO Thus~ as shown in a front view A in Figure 16, the pressing construction of a conventional weighting arm i~ such that a compression coil spring 23 is supported at its upper end surace by a spring position controlling projection 25 on the ~3~9 ceiling of a guide anm case 21 while it~ lower end surface issupportsd under pressure by a spring position controlling pro-je~tion 26 provided on the outer ceiling surface of a weighting arm 22. Dri~en rollers 24, 24' orthogonally supported at its middle by the weighting arm 22 are opposed to a driving body in the illustrated relation. ~herefore, the horizontalne~s of tha pressure contact surface of the pressing spring 23 posi~ioned on the outer ceiling surface of he weighting arm is governed by the manner of contact between the driving surface D and the driven rollers 24, 24'. ~he weighting arm construction is subjected directly to various influences from factors including the hori-zontalness of the pressing surface of the pressing 23 and the intrinsic deviation of the pressing spring 23 during operation of the waighting arm 22 and the angle of deviation es of ~he center axis of the compression spring 23 due to the displacement of the pressing center P of the guide arm 22 with respect to the longitudinal datum axis ZZ' extending through the weighting point P of the weighting arm construction, with the result that an overall vector Pl acts on the weighting armO
The overall vector Pl has an angle of deviation ~0s with respect to the datum vertical axis Z2' of the weighting arm con-structionO From this relation, the driven rollers 247 24' have a thrust E produced in the direction of their rotative axis xx' which is a component thrust in the anti-restoration direction of the guide arm~
The siæe of the thrust E, as seen in a vector diagram shown in Figure 16, B~ is express~d as follows~
E = Pl sin ~es~oooo-00(5) Therefore, the deviation torque ~s which is a moment in the ~3~g deviation direction acting on the point P of the guide arm 22 and produced by a pressure a~ting on the guide arm 22 is expre~sed by the following equationO

Ms = s P sin ~osO~oooo(6) On the other handJ as shown in a plan view C in Figure 16, the guide arm 22, under the influence of the deviating actio~, is positioned displaced by S e relative to ths datum axis YY' in the weighting arm construction extending through the center of swing motion o of the arm 220 Thusg from the equation (4) the restora-10 tion torque Mr produced at the center point Q of the drivenrollers 24, 24 ' is expressed by the ~ollowing equationO
~ r = 2 1 Vo sin~eOO0.00(7) The two kinds of moments, namely9 the deviation torque Ms and re-storation torque Mr having different directions described above sLmultaneously act on the weighting arm Ql at points P and Q.
Therefore, the guide arm OQ continues to remain at a position where the ~wo torques are balanced.
Ms = MrO0Ø0..0(8~
As shown in a plan view in Figure 16, C, with the weighting arm constructed to have rotatable rolls on opposite sides of the holding shaft oiE the guide arm, equal thrusts Tl and T2 are pro-duced on opposite sidesO Therefore, the equation (8) is developed as follows~

- 2 1 V sin S~ = S Pl sin ~5 sin ~e = S Pl sin 5 e = 1 sin~l~s Pl sin ~ 0O.OOOO(9) 2 ~ 1 V
It is evident from t~e ~quation (9) that it is necessary and sufficient condition for O = O that l~s - OO That is, unless ~3~
the pressing vector line coincides with the weighting datum axis ZZ' in the front view in Figure 16, A, it will not return to the origin Q. The condition ~6s = 0 theoretically is at the weight-ing arm original position where XX' 11 xx' 11 ~Y', and this condition is no more than the absolute parallelism of the rotative axis xx' of the driven rollers with respect to the right-angle axis XX' of the bottom driving surface Do This proves the fact that the self-aligning property of the top rollers with respect to the driving roller D of the pendulum type weighting arm is very imperfectç In ordar to achieve higher aligning performance here-tofore demanded at job sites, iOe. the allowable deviation range within 003 mm indicatRd in Figure~ 5 and 6~ it is required in an aspect of basic design to minimize or eliminate the pressing deviation characteristics of the individual pressing bodies or pressing assemblies. ~owever, it is evident also from investi~
tated data that it is impossible even by the exi~ting technique to include the limit of management of tens of thou~ands or hundreds of thousands of lots in the above r~nge. In this con-nection, Figures 5 and 6 prove that even the typical weighting arm which is produced with the highest level of technique and according to the best principle has been still in~ufficient to improve quality and op~ration in practice~ Weighting arms used especially in textile mills are the key to forming a roller nip which governs the quality of spun yarn and operating efficiency~
ThereforeJ it is an important subject to improve the parallelism of the driven rollers R with respect to the driving bottom roller D in that case~
~ he present invention has been developed in view of the above and relates to a construction wherein on the assumption ~3~;g that the pressing deviation charactexstics peculiar to a pressing body or assembly which are the main cause of troubles are allowed to eXist at substantially the pre,sent level, a rolling-contact bearing element or rolling assembly i9 interposed between it and a guide arm to isolate them from ~each other, the function of the rolling element being utilized to elL~inate the deviation vPctor while transmitting only the necessary pressing vector directed in the direction of the vertical datum axis ZZ', thereby making fullest use of the self-aligning principle and function of the known pendulum arm systemO
Weighting arm assemblies according to the prssent invention may be arranged in a plurality of row~ inside the weighting arm body, whereby they can serve as a weighting arm device capable of performi~g the necessary and sufficient weighting arm function for the respective lines in ~he draft sectionO Therefore, the invention has high rationality in that it has the versatility to adapt for the production of many kinds of types or standards of weighting arm and has as well the capability of being applied as a ~tandard form so as to provide for mass-productionO In parti-cular, the significance o~ its capability in opening the way Eorhigh rationali~ation of manuacturing facilitie~ is higher than expected~
As regards the effects of the invention on the performance of the weighting arm used in a spinning frame, a great Lmprovement can be obtained in the parallelism of the axes of the bottom and top rollers D and R, and this is highly advantageou~ in improving the quality of yarn material~ The improvement of the quality of yarn material not only contributes to an improvement of the quality of the textile end products but also increases the ~3~g operating efficiency and productivity o~ spinning proce~se~ andat the same time minimizes the occurrence of defects in the yarn and has marked effects on the production efficiency and on the productivity of secondary processes and those that follow. For example, when a yarn material providing about 0o5-1~ increase in ~ of 40s combed yarn is used, there is for example an ex-pectedly high percentage improvement in the quality and efficiency of tht3 weaving and o~ the weaving proces~ 9 as shown in the table of Figure 250 This is why the requirements ~or the quality of 10 yarn material are becoming increasingly severe in proportion to advances in the proce~sing facilitie~ and in the ~ubsequent pro-cesses, and in the diversification of productsO These conditions can hardly be satisfied with the present level of paralleli~m found in the existing weighting armsO (See Fi~ures 5 and 60) ~hus~ the requirement~ for the weighting arms in the spinning frame are high. That is, the problems of, ~or example, firstly increasing the pressure, secondly stabilizing the quality, thirdly, convenience of operation, and fourthly freedom from maintenance are all difficult to solve. Even the mo~t modern weighting arm uni~., iX frankly criticized from the standpoint o~ an expert, ha~ many problerns including tho~e described above which are yet to be solved. That is, whereas great merits are provided by the. weighting arm unit, the Lmportant aspect of ~tability i~ sacrificed to convenienceO
Among other things, it is pointed out that it is in the parallelism of the top roller that the greatest drawback is exposedO Needless to say, the parallelism oE the top roller directly govern~ the performance of the draft section, f~rming a main factor affecting the quality of yarnO The improvement

3~
thereof will result in rais ing the level of textile technologyO
In brief~ the present invention is arranged to enable all the top rollers associated with the spindles in a 3pinning Prame to be confined within the allowable range of deviation of the paralleliQm of top rollers (where no yarn unevenness takes place)0 Thus 9 the invention i~ significant.
In addition, the invention provides a self-aligning type weighting arm construction which is ucable not only with textile machine~but al80 with other similar machines using a parallel-10 hold type ro atable press roll assembly.
Figures 17 and 18 show embodiments incorporating thebasic nature of the present invention, and the structural concept hereoP will now be described~.
(1) The ~onstruction of a support point 0 for the swing motion of a guide arm A in the rear is by the pivot-wise support methodO
(2) A rolling element i8 received in the lower end surface of a pre sing spring SO There is pxovided a bottom cap HB of the illustrated shapeO For exam~le, in the case of a compression coil spring9 an inverted U-section cap is provided and this cap H.B receives a rolling element3 for example a ball K or a cylindrical roller or a shaft-equipped rollerO The upper inner surace X3X3' of the bottom cap i~ arranged so that with respect to the upper surface X5X5' of the guide arm ca~e it is maintained in the relation X3x3'l1 X5X5' during operation.
~ 3) At a predetermined position on the upper surface oP the guida arm oppo~ed to a pressing body or pxe~sing a3sembly9 a rolling contact flat ~urface portion X2X2' is formed to provide a small guide surfaceO

~43(D~;~

(4) Even if (2) and (3) are reversely installed, the resulting arrangement will be exactly same in function with some exceptions.

(5) The pressing ~pring S is usually in the form of a compression coil spring. The 90-~degree anyularity of the opposite end surfaces of the spring S wi~h respect to its longi-tudinal axis, and the parallelism of said opposite end surfaces are strictly controlled according to JIS (~apanese Industrial Standard)~ Although some ~catter i5 produced, if it i~ within the range specif ied by JIS~ experiments have proved that such scatter does not matter. In in~talling the spring S, its upper surface is vertically fitted on a projection 25 formed at a pre-determined po~ition on the upper end of the guid~ arm case. The inner surface X3X3' of the bottom cap HB mounted on the lower surface of the pressing spring S in this condition could retain a nearly horizontal condition but ~is can hardly be said to be sufficient~ In the present invention, therefore, the bottom cap HB i~ combined with the pressing spring S in such a manner that the clearance with respect to the diameter of said epring ~whether ~he inner or outer diameter) is minimized and a~ the same time it i~ combined with tha guide arm case B ( in some ca~es, the arm body) in such a manner that the clearance between the diameter (or width) d of the b~ttom cap B and the widthwise in~ide di-men ion w of the guide arm case is similarly minimized. As a result of this design, the vertical axis of the pressing spring S approximately coincides with the datum axis ~' of the width of the ca3e. Thus, this arrangement assures that the pres~ing spring S will be maintained upright at the predetermined position on the end surface X5X5' of the guide arm ca~e BJ while minimizing ~ 23 -3~)~9 the sources of deviation such as the buckling phenomenon, so thatthe axis of the spring substantially coincides with the central axis of the width of the guide arm case B and hence the pressure exerted by the spring acts vextically. In response thereto, the ceiling surface X3X3' of the bottom cap HB maintain~ the altitude x5x5~ 11 X3X3' o that through the pressing structure using the ball or other rolling element K contained in the bottom cap ~, the pressure of the spring S is transmitted to the end surface X2X2' of the guide arm B in the correct direction, that is, only the required correct pressure obtained by elLminating the intrin~ ic deviativity of the pressing spring S is transmitted.

(6) On the other hand, the self-aligning function of the driven roller ~ provided by the driving of the driving body D
acts in accordance with the principle described a~ove, producing a self-aligning swing motion of the weighting arm A around the fulcrum 0. As a result, the resistance to the rolling of the rolling element K at points of contact 27~ 28 between the end surface X2X2' and the end surface X3X3' of the bottom cap HB i9 minLmized almost to zero~ Thus, an ideal pendulum type weighting arm con~truction allowing the guide arm A to swing independently of the pressuxe and without any substantial resistance can be obtained. As for the parallelism of the upper and lower races XX' and X2X2' between which the rolling element is interposed~
some amount of tilt relative to each other away from paralleli~m cannot be avoided in practiceO However~ in the present system in-corporating compensating means as described above~ the relative tilt remains withln a very small range and no slippage on the races occurs since the pressure being transmitted act~ to increa~e the res i~tance. In brief, the most characteristic feature of the present invention cons ist~ in the fact that the 2~rrangemerlt ~43~i~9 comprising a rolling element interposed between the bottom surface X3X3' of the pressing body and the upper ~urface X2X2' of the weighting arm on the pressed side provides three different functions, namely, a rolling function, a pressure transmitting function and a ~unction of elLminating the deviative pressure vector component:of the pressing body between the races defined by the upper and lower parallel surfaces between which the rolling element is held~ That is, the invent.ion has opened a new way for maintalning the resistance to the sel~-aligning swing motion of the weighting arm alway~ at zero even under high pressure and fully developing the pendulum performance. As a result, a rolling support type prsssing construction i5 formed which re-sponds to the restoration torque automatically produced on the weighting arm side with very high sensitivity even under heavy load, whereby the pure pre~sure which does not interfere with the pendulum function of the wei~hting arm ~ is accurately trans-mitted to the top roller R~

(7) In the draft aection of the textile machine, the angle of ~wing of excessi~ely large amplitude found in the exist-ing pendulum arm i~ unnecessary and moreover, in most ca~e~,superfluous swing is harmful. Particul~xly in the large-sized heavy-load weighting arm demanded in recent years, the exce~sive-ness of the angle of swing has close correlation with the de-gradation of the parallelism of the top roller Ro - The present invention has investiaged the principle of the self-aligning function of the pendulum ~ystem heretofore sought after as the ideal arrangement for the weighting arm and has opened a new way for most reasonably making efficient use of it.
Further, the invention has investigated the causes of the ~3Q~9 degradation of the parallelism found in the conventional sy~tem~
and has as one of its features the fact that in order to in-cre~se the stability necessary for advantageously U9 ing the intrinsic features of the conventi.onal systems, a particularly limited range is set for the angle of 3wing of the weighting arm A and the limit value of the effective amplitude thereof is a~sociated with the range of cumulakive error produced during manufacture of weighting arms 50 as to limit the amplitude to an allowable minimum by special means. Thus, the invention has successfully provided a construction having a perfect self-restoration function by applying a unique idea based on the above descxibed various concepts and experiments to make rea~on-able use of the principle of the self-alignment of the pendulum system.
As is evident from the above~ in the present invention~
the long experience and information concerning the characteri-stics of the xi~ting typical weighting arm have been sy~temati-cally arran~ed to investigate and grasp the merits and demerits of ~aid weighting arm~ The conclusion is that the principle of the ~elf-alignment of the known pendulum 4ystem i~ theoretically quite correct and~ if correctly applied, will provide ~.uperior stable functiolls most suitable for the weighting arm. The rea30n why the parallelism of the top roller R is disturbed i~ that the defects of the weighting m~ans for the weighting arm impede the performance of the top roller, as described a~oveO Thus, the conclusion i~ t:hat even if the pre~ing means or pre-~ing device has its intrin~ic dire~tionality, the correct self aligning function peculiar to the pendulum type arm can be derived if ~ome measure i~ taken to eliminate the influence of said 3~69 directionality. In the pr~sent inventionJ therefore, a method is employed which denies the se].f-alignme~t of the conventional weighting axm construction and lncorporates a rolling element or device between the weighting anm A and the pre~sing body or pres~ing assembly SO
Th~ arrangement of the invention will now be described in more detail wi~h refs~ence to Figures 19 through 24.
Figures 19, 20 and 21 show the relation betwe~n the bottom ~ cap HB holding the rolling element K and the guide arm case B
and also 9hOW various attitude~ at points of contact 27, 28 be-tween the rolLing elemant K and the bottom cap HB and guide arm Ao In Figure 19~ Figure A shows a front view of the weighting arm davice and Figure B ~hows a s ide view thereof . In Figure A, a recesg M is formed at a regio~ of the guide arm A where the rolling body K is pressed thereagainst. The configuration of the recess is ~uch that when viewed in the side view B, it is an arcuate groove having a radius R' ~omewhat greater than the radius R of the ball K and that when viewed in Figure A it hag a radius R e~ual to the radius R of the ball K with its center displaced by a di3tance ~ so as to form a f lat surface over the distance ~ ~ . Since the ball K rolls within thi3 recess M, the h~rizontal swirlg of the guide arm A i~ performed in the range of aid flat surface a ~, thereby making it po~sible to control the swing angle of the weighting arm Ao The portion of the ball K greater than its radiu~ is received in the inside pocket of the bottom cap HB with some clearance therebetween so ~hat there is no interference with the rolling of the ball K. FurtherJ in the side view BD the de~ign of the cross-section of the groove M

~43~69 does not allow the horizontal di~placement of the ball K, thu~
maintaining the contact point 27 on the datum axis ZZ'.
On the othex hand7 the bottom cap ~B is fitted in the guide arm case B with a minimum clearancs therebetween and, if nece~sary, it occupies a height h. As a result, there is obtained the function of compensating for the influence of the deviation tendency or buckling phenomenon peculiar to the pre~ing -pring S.
Although the control of horizontal displacement of the bottom cap ~B as viewed in Figure B is omitted in this 3ystem~
there will be no difficulty in practice ~ince the ball K is con-trolled by the race groove M in the guide arm A.
Figure 20 shows a sy tem in which ths ceiling plate of the guide arm A is formed with a rectangular race groove M for use as a race for the ba~l Ko In this case, th~ amount of rolling di-~placement of the ball K is controlled by the dimension o~ the longer side a of the rectangle, as shown in the front view Ao Furtherl as seen in the side view B, since th~ race for the ball K ha~ a groove width b, the ball K contacts he race at two edges 27 and 27', whereby the same operating condition as in Figura A i~ established. In Figure A, although the bottom cap HB is loo~ely fitted in the guide aLm case B only by mean~
of its plate thicknes~, this i~ sufficient if the accuracy of the pre3sing spring S is good.
Figure 21 show~ a system }:elonging:: to the most typioal o the embodiments of the invention. As shown in the front view A, swing control projectivns 29, 29' are provided at parti-cular po~itions on opposite outer surfaces of the guide arm A.
This idea is ~imilar to that of using the previously describsd ~ ~3(~6~
control pin (see Figures 11 and 12) and there is lef~ a swing clearance ~ relative to the ins:ide dimension of the guide arm case Ao This relation correspond~ to the plane distance ~
shown in Figure 19, Ao Instead~ it becomes unnecessary to form a reces~ in the upper surface of the guide arm Ao The other conditions are the same as those sf the system shown in Figure 19. ~owever, a construction is added wherein guide projections 30, 30', 31, 31' disposed on opposite inner surfaces of the guide aLm ca~e B to surround the outer periphery of the bottom - 10 cap HB, as shown in the plan view C in Figure 21, control the movement of the bottom cap HB so that it moves only in the correct spring pressing direction, i~eO in the direction of the pressing axis of the pressing spring without deviating in any other direction~. This construction can ba applied, without any change, to the embodiments shown in Figures 19 and 20. Figure 22 shows another embodLnent coneerning the rolling intermediary.
As shown, thi~ embodiment belongs to the type Nsing a roller K
having a shaft.
Figure 22, A, shows a front view and B shsws a 9 ide viewO
20 ~igure C is a par~pective explanatory view. Figure D show~ a weighting arm construction us ing ~ plate spring S ' as the pre~-ing spring S and also using a roller K having a shaft.
~ he system shown in Figure 23 is same as that shown in Figure 22 in that it uses a roller K, but the way the shaft o~
ths roller is assembled is different. Thus, as contrasted with the system of Figure 22 having the sha~t attached to the bott~m ~ap HB, the syqtem of Yigure 23 has the shaft attached to the upper plate portion of the guide arm Ao At any rate9 the systems shown in Figures 22 and 23 have the advantage that the rolling element K, which is an intermediary, can be stabilized by ths ~436~69 setting of the ~haft and hence the swing action of the guidearm A is further stabilized. However, in some cases~ such con-struction tends to become complicated and, on the other hand, sLmplification involve~ some cau~e of ~lippage. Some amount of slippage does not matter so much and this sy~tem is convenient in ca~es where priority should be given to stabilization.
The embodLment shown in Figure 24 is an example of the so-called universal type weighting arm construction appl~ able to the various lines (front roller, 2nd.roller, 3rd roller, etcO) in the draft section of a textile machine, In Figure 24, the swing axis O for the weighting arm for supporting one end of the weighting arm A i~ locatsd at the lower end of the guide arm case B. The other end of the weight-ing arm A is provided with a stay kn~b 43 which is received on the lower edge of a rectangular opening 14 formed in the guide arm caseO The arbor G of the top roller R i5 securely held at right angles by a central lower inverted U-shaped gxoove in the guide arm A. The opposite ends of a pressing coil spring S are provided with a top cap 32 and a bottom cap 31 to form parallel surface at right angles with the central axis of the æpring S
: extending along said opposite end urfaces.
The upper surface of the guide arm is formed with a race for the ball K,. Usually, in the race for the roller arrangement, the center of the roller K is located on the datum axis XX' of the weightiny arm construction so that the roller will not dis-place forwardly or rearwardly of the guide arm A, while a particular limit range is provided in the direction of swingO
Thus the arrangement is s imilar to those shown in Figures 19-21~

More than the upper half of the ball K is received in the bottom 16~43~DG9I
cap 31 and its top i~ in contact with the end surface thereof under pressureO
The bottom cap 31 and top cap 32 are fitted in the inner diameter of the pressing spring S with a minLmum clearance there-between and their outer ~urfaces are fitted likewise in the guide arm case B with a minimwm clearance therebetween, ~o thak they are slidable only in the pressing directionO The upper assembly 36 of the guide arm case B forms an attaching base part for selectively fixing the weighting arm assembly at a predeter-- lO mined position an the weighting arm main body 42 and also serves a. a base for adjusting a screw 35 which adjusts the pressure of ths press ing ~pring S .
As for the spring pre~sure adjustment, this embodiment shows a basic system using a screw and gauge plate 41, but this is an example only9 since many methods may be used, including one using a stepwise adjustable top-shaped cam and one using a combination of a lever device and a c~n devicaO Therefore, the invention is not l~nited to the screw adju~tment type. Further, pins 38, 38' illustrated are an example of means ~or uniting the upper and lower assem~lies 36 and 37 of the guide arm case B.
It is also po~sible to form them integrally with the guide arm case B, While there have be~n describ~d herein what are at pre~ent considered preferred embodiments of the several features of the invention, it will be obvious to those skilled in the art that modifications and changes may be made without departing from the essence of the ~vention.
It i~ thQrefore to be unders tood that the exemplary embvdi-ments thereof are illustrative and not restrictive of the - 31 ;

~L~43~
invention, the ~cope of which is defined in the appended claim~
and that all modif ication~ that come within tha meaning and range of equivalency of the cla~ras are intended to be included the rein.

Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a pendulum arm type, self-aligning weighting arm assembly for use with textile machinery and having casing means, said casing means including a pivot member, weighting arm means pivotally mounted at one end to the said pivot means of said casing means for movement in a plurality of directions rotatably driven roller means rotatably mounted on the opposite end of said weighting arm means, driving body means operatively positioned with said driven roller means for rotating same and pressing means operatively engaged with said weighting arm means intermediate the ends thereof urging said driven roller means into engagement with said driving means, the improvement of the pressing means comprising cap means U-shaped in cross-section positioned in the lower end of said casing means for vertical movement therein, a rolling contact bearing element positioned within said casing means and between the bottom of said cap means and the top surface of the weighting arm means intermediate its ends thereof and in bearing engagement there-with, and spring means positioned in said casing means and above said cap means positively urging said cap means vertically downwardly against said rolling contact bearing element.

2. A weighting arm as set forth in claim 1, wherein the rolling contact bearing element is a ball.

3. A weighting arm as set forth in claim 1, wherein the rolling contact bearing element is a cylindrical roller.

4. A weighting arm as set forth in claim 1, wherein the rolling contact bearing element is a spherical roller.

5. A weighting arm as set forth in claim 1, wherein said cap means include means for controlling the effective rolling range of the rolling contact bearing element.

6. A weighting arm as set forth in claim 1, wherein the upper surface of the weighting arm includes a recess for ontrolling the range of movement of the rolling contact bearing element.

7. A weighting arm as set forth in claim 1, wherein the upper surface of the weighting arm includes an opening for controlling the range of movement of the rolling contact bearing element.