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Патент USA US3089666

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May 14, 1963
Filed Jan. 5, 1961
2 Sheets-Sheet 1
FIG. 41
May 14, 1963
Filed Jan. 5, 1961
2 Sheets-Sheet 2
United States Patent 0
. IC€
Patented May 14, 1963
FIG. 7 is the theoretical package outline correspond
ing to the pro?le of FIG. 5;
FIG. 8 is an enlarged diagram‘ of one of the reversal
Pern Joseph Chaussy, Camden, S.C., assignor to E. L
du Pont de Nemours and Company, Wilmington, Del.,
points shown in the pro?le of FIG. 5; and
FIG. 9 is a top plan view of a ‘barrel cam having a
a corporation of Delaware
groove corresponding to the pro?le of FIGS. 5 and 8.
The winding apparatus chosen for purposes of illus
Filed Jan. 5, 1961, Ser. No. 80,922
4 Claims. (Cl. 242-43)
tration in FIG. 1 includes as components thereof a rotat
This invention relates generally to the traverse wind
a‘bly driven barrel cam 10 having a groove 12 in its cylin~
ing of yarn at high speeds and more particularly to im 10 drical surface and a follower 14 having a yarn guide at
provements in the cam. which is an integral part of the " tached thereto which follower rides in groove 12 and is
constrained to a linear path of travel by rails 16, 18.
Winding apparatus.
It is well known in the textile ?eld to wind substantially
The magnitude of the acceleration forces imposed on
cylindrical packages of yarn, thread or the like on a
bobbin in a traverse winding apparatus. In such an ap
paratus the yarn passes through a reciprocating guide to
a rotating package. The guide is attached to a follower
which rides in a generally helical groove in the surface
of a rotatably driven ‘barrel cam and is constrained to
a cam follower is a function of the radius of the reversal
curves with the practical minimum radius being limited
by the ability of the follower to withstand high inertial
It is known that traverse cams with sharp con
stant velocity reversal patterns subject the follower to
instantaneous acceleration shocks. Where the reversal
follow a reciprocating linear path of travel. An appa 20 pattern is circular, the shocks are not instantaneous but
ratus of this type has been disclosed by Hunter in US.
are nevertheless abrupt.
A cam pro?le having harmonic reversal curves has been
Patent No. 2,689,694. Although such an apparatus is
entirely suitable for use at the speeds contemplated, it
designated with the numeral 20 in FIG. 2. When such
has been found that higher winding speeds lead to the
a pro?le is milled into a cam of the type shown in FIG.
formation of unstable packages having bulged end faces 25 1, it produces gradual acceleration changes and is accord
ingly ideally suited for use in a high speed ‘apparatus.
and overthrown ends. These unacceptable results are
Even with such gradual acceleration changes, there is
caused by the reduction in follower velocity in the cir
cular reversal portion of the cam pro?le and the concur
still a deposit on the package of surplus yarn or shoulders
rent deposit of surplus yarn at the package ends. In the
22 (FIG. 4) opposite the reversal points. The pressing
past, it has been thought that a relatively sharp, angular 30 action of a drive rol-l (not shown) which is in frictional
contact with the package surface assists in redistributing
reversal portion in the cam pro?le would eliminate the
buildup of shoulders. Actually, the shoulders still ap
the yarn from the theoretical outline shown in FIG. 4 to
the actual though exaggerated saddle Iback shape shown
pear. Furthermore, such a remedy is unpracticable be
cause of the high acceleration forces acting on the fol
r in FIG. 3.
In FIGS. 5 and 8 the preferred cam pro?le of the
lower and guide, i.e., the nearly instantaneous change in
present invention is shown and has ‘been designated with
direction subjects the follower to excessive acceleration
the numeral 24. Pro?le 24 includes straight portions
and loads.
The principal object of the present invention is to pro
26, harmonic reversal curves 28, and intermediate
cycloidal curve portions 30. In each portion 30‘, there
vide cam pro?le improvements which facilitate the forma
tion at high winding speeds of stable, substantially cylin 40 is a change of cam direction or slope which results in a
gradual acceleration of the follower as it leaves a straight
drical, uniformly dense yarn packages having ?at end
A corollary objective is the provision of a cam pro?le
portion 26 and a gradual deceleration as it leaves a
harmonic curve 28. In the actual reversal portion 28 full
which facilitates high speed ‘winding without subjecting
advantage is taken of the gradual acceleration character
the cam and follower to excessive loads at the cam re
istics of a harmonic curve as discussed above in connec
versal points.
in its surface, a cam follower riding in the groove and
tion with FIGS. 2-4. The stroke limit or reversal point
for follower 14 is at the mid-point of harmonic curve 28.
The overall increase in velocity in the approach to and
departure from the reversal point leads to a theoretical
cutback 32 .(FIG. 7) near the ends of the package. In
guide rails limiting the follower to a reciprocating linear
path of travel between the cam reversal points. A suit
able yarn guide is attached to the follower for movement
to harmonic curves 28 slip into the low density regions
or cutbacks 32 corresponding to cycloidal curves 30.
These and other ‘desirable objectives are accomplished
in a Winding apparatus which includes a rotatably driven
barrel cam having a continuous, generally helical groove
actual practice, surplus yarn shoulders 22’ corresponding
The cam groove is characterized by succes 55 The pressing action of the package drive roll assists in
sive straight, cycloidal, harmonic, cycloidal and straight
this redistribution of yarn.
portions in its pro?le at the reversal points.
Other objectives will become apparent in the following
speci?cation wherein reference is made to the accompany
the package faces ‘are ?at, as indicated at 33. Since cut
backs 32 result from an increase in follower velocity in
ing drawings in which:
Cutbacks 32 disappear and
the cycloidal portions 30 of pro?le 24, portions 30‘ are
also referred to as cutbacks in the pro?le.
The apparatus
FIGURE 1 is a partial elevational view of a traverse
shown in FIG. 9 has a cam groove 12' corresponding to
winding apparatus into which the improvement of the
present invention may be incorporated;
the pro?le of FIG. 8 but is otherwise identical to the
FIG. 2 is a cam pro?le having harmonic curves ‘at the
reversal points;
FIG. 3 illustrates the package outline which results
when the cam pro?le of FIG. 2 is employed;
FIG. 4 illustrates the theoretical Package outline cor
responding to the pro?le of FIG. 2;
FIG. 5 is the cam pro?le of the present invention;
FIG. 6 shows the actual package formation resulting
when the cam pro?le of FIG. 5 is employed;
apparatus of FIG. 1.
Although the cutback portions 30 of the preferred
65 pro?le are cycloidal, it is practicable and sometimes ad
vantageous to use other curves of varying radius, e.g.,
polynomials, as the junctures between the straight and
harmonic curve portions. The principal requirement is
that the acceleration characteristics at both ends of the
transitional or cutback curve blend with the acceleration
characteristics of the adjacent curves.
As is apparent from the tangent lines shown in FIG.
8, the cutback portions 39, join constant velocity portions
I claim:
26 and harmonic portion28 atpoints of zero accelera
1. A winding apparatus including a rotatably driven
barrel cam having a continuous generally helical groove
tion. Thus, the follower 14 enters a cutback portion 30
in its surface, a cam follower riding in said groove and
at constant velocity, accelerates to some ?nite value and
leaves the cutback portion at zero acceleration. The 5 means limiting the follower to a reciprocating linear path
of travel between the cam reversal points, said follower
transition is continuous and smooth with no sudden or
large changes in acceleration.
having a guide ?xedly attached thereto and said groove
having a pro?le including successive straight, cutback
curve, reversal curve, cutback curve and straight portions,
maximum pressure angle 99 for the pro?le of this inven
tion exceeds the normal pressure angle or cam helix angle 10 said pro?le being entirely curvilinear in the portions in
With reference to FIG. 8 it should be noted that the
88 by the size of the cutback angle 77.
Previous cam
terconnecting said straight portions, said cutback curves
Substantially cylindrical packages of ‘heavy industrial
being respectively curves of gradual acceleration and
deceleration, each reversal curve having gradual decelera
yarn have been wound at high speeds using a cam hav
tion and acceleration characteristics respectively in the
pressure angle 99 of over 40°.
portions are cycloidal.
pro?les have not included a de?nite cutback angle 77.
ing a cutback angle 77 as large as 13°, a helix or normal 15 approach to and departure from said reversal points.
2. The apparatus of claim 1 ‘wherein said cutback curve
pressure angle 88 of about 30°, and a maximum or total
Similarly, a cutback angle
3. The apparatus of claim 1 wherein the cutback angle
is at least 4°.
suitable for lighter textile counts. Between these two
extremes cutback angles of from 4°-13° have been used 20 4. The apparatus of claim 1 wherein the maximum
pressure angle is in excess of 30° and the cutback angle
successfully in the winding of various nylon, polyester,
is at least 4°.
and spandex ?ber counts at windup rates approaching
References Cited in the ?le of this patent
5,000 yards per minute.
Although the preceding description relates primarily to 25
the use of barrel cams, it is apparent that the concept of
Anderson _____________ __ Nov. 2, 1920
adding a cutback portion to a cam pro?le is equally ap
Siegenthaler __________ __ Nov. 4, 1958
plicable to plate and other type cams. Additional
Steeger ______________ __ Apr. 26, 1960
changes to and adaptations of the disclosed cam pro?le
Metzuer _____________ __ Nov. 15, 1960
may be made without departing from the spirit of the 30
present invention which is accordingly intended to be
of as little as 4° with a cam helix angle of about 30° is
limited only by the scope of the appended claims.
France _______________ -_ Oct. 7, 1953
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