Improvements in Apparatus for Stretching and Drying Fabrics.
Year: 1898

page_text: [Communicated from abroad by The Firm of C. H. WEISBACH, Maschinenfabrik,
Chemnitz, Saxony, German Empire.]
Improvements in Apparatus for Stretching and Drying Fabrics.
I, PHILIP ARTHUR NEWTON, of the Office for Patents, 6, Bream's Buildings,
Chancery Lane, in the County of London, Patent Agent, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
-
In the present variable-tension stretching machines, and more especially in those
machines in which the stretching chains themselves (and not the guiding frames,
or rails for these latter) are variably driven, two evils in particular present them-
selves, that is to say:-
1. The goods cannot be guided on the stretching chains with uniform selvage
speed, as in ordinary stretching machines, but, instead, when arriving on the chains,
and following their variable travel, are subjected to various injurious pullings,
draggings, and tearings.
2. The tension of the weft thread,--influenced by the variable travel,-is, in the
lower or back travel of the fabric, not compensated for as uniformly as in the
upper or forward travel of the fabric, it being absolutely necessary that the upper
and lower travel shall be subject to equal tension, which is not attained when the
compensating mechanism swings in an arc. To attain this result, the said
mechanism should have a parallel movement, by which equal tension may be
imparted to the upper and lower portions of the fabric.
The object of the present invention is an improved mechanism which is designed
to overcome the evils above mentioned, and I will now proceed to describe this
equalizing fabric-feeding apparatus.
As shown in elevation and plan view in Figs. 1 and 2 of the accompanying draw-
ing, short converging or parallel adjustable side frames tt' are pivoted to the ends of
the diverging chain supporting frames 6 b¹ of the normal feed portion of the machine.
Mounted in these short frames t¹ is a uniform chain driving and compensation
mechanism.
This latter consists of loose chain wheels EE and H H¹, running on stud axles
carried by suitably guided slides M M' and N N', which fit in the frames tt. These
chain wheels are held in contact with the stretching chains, the upper ones E E'
by levers KK with adjustable weights LL¹, or by weighted belts passing over
rollers, and the lower ones by ordinary weights 001, guide pulleys CD, and C¹ D'
running on fixed stud axles on the short frames tt, thereby providing for the
necessary retention of the stretching chains upon the wheels E and E¹. The
front chain wheels B B are mounted on a transverse shaft which has its bearings in
the frames tt, driven by worm gearing, and at a uniform rate of speed. These
chain wheels B B¹ guide the chains in a uniform manner to the wheels EE, and
immediately in front of these wheels the varying travel of the chains commences,
which travel is caused by the chain driving wheels A A¹.
The means by which these chain wheels AA¹ have imparted to them the
periodically changing accelerated or diminished speed, and the means by which

page_text: the uniform speed is transmitted to the wheels B B¹, is of little moment, as this
transmission of motion may be effected in any suitable way. I shall therefore only
briefly describe the construction illustrated in the accompanying drawing as being
the form of driving gear that is mostly preferred.
On the axles which carry the wheels A A' are keyed the worm wheels QQ
These axles, which are in line, and work independently of each other, are carried
at their inner ends in a central bearing R, and at their outer ends they run in
bearings in the main framing.
יי
PP are worms into which the worm wheels gear. These worms are carried upon
shafts cd turning in bearings, and lying parallel to the direction of motion of the
fabric. They are connected to their shafts by feathers which permit of their being
shifted endwise to act momentarily as racks in either direction on the worm, wheels.
This shifting motion may be readily effected by a suitable lever mechanism con-
trolled by any well known device, with the object of enabling the worms to
alternately accelerate and diminish the rotation they impart to the chain. driving
wheels A A¹, and control the travel of the stretching chains in a correspondingly
variable speed.
Upon the shaft c carrying the longitudinally sliding worm P₁, and also the stepped
driving pulley U for the main driving belt, is keyed a second worm S, which gears
with a worm wheel T, and from this, through suitable intermediate gears, drives
the chain driving wheels B B' with uniform speed.
The reason for driving the chain uniformly by the tension-driven wheels BB', is,
that the fabrics are guided on the chains in precisely the same manner as in the
present stretching machines, the wheels E E¹ and H H serving merely to equalize
the heterogeneous effect of the uniform and variable driving of the stretching
chains, so that they compensate for any straining and crowding of the chains that
may occur.
The result of the compensation effected as above described by the chain
wheels EE in combination with the wheels HH', is, that the fabric enters the
machine at a uniform travelling speed, which is converted into an alternately
varying one through the chains on the two sides of the machine, by the mechanism
described.
For the proper action of the above described compensating mechanism, the
uniform tension driving gear for guiding and driving the chains at the entrance of
the machine at B B is essential (without claiming such), and in order to make
the automatic action of the compensating mechanism possible, the arrangement of
the short converging adjustable frames tt is particularly necessary, there being no
lateral tension put upon the fabric by these; therefore the compensation mechanism
is constructed in connection with the converging frames (entrance field), and not
on the diverging part of the chain guides, or on the parallel stretching and drying
field.
The means devised for producing and maintaining a periodically variable tension
upon the weft threads of the fabric by the varying speed of the stretching chains
in a satisfactory and exact manner, will now be described.
Of the two chain-guiding frames 77', a fixed adjustment for g¹ is provided by
means of screws f carried by the main framing and a trolley g fitted with rollers
and supported by suitable cross beams p, the above described arrangement being
for the adjustment or setting of the frame q¹ in accordance with the width of the
fabric in hand.
To the other chain guiding frame 9, which takes no part in the adjustment of
the width of the machine, there is imparted solely the function (distinct from its
qualification of guiding one of the chains) of swinging itself to and fro to the
adjusted frame q¹, and in such manner as may be necessary to compensate the
influence of the tension on the weft threads caused by the alternately varying
travel of the wheels A A¹.
The chain frames y are supported for the above mentioned oscillating motion by
a parallelogrammic system of levers (as shewn in Figs. 3 and 4), which are arranged

page_text: in number equal to the worm shafts for the parallel field guides. Each of these
supporting systems consists of (1º) two powerful flat springs h having their upper
ends fast to the oscillating frame g, and their lower ends bolted in any convenient
manner to the main framing; (20) two small brackets r fixed to the shaft bracket;
(30) two upper curved brackets i bolted to both the spring bar h and the frame;
(40) a lever m pivotted at top and bottom by means of its forked ends to the
brackets i andr; and (5%) an antifriction bowl o situated between the top fork
of the lever m and the top bolt k.
On a shaft S, mounted horizontally in suitable bearings cast with the shaft
bracket, and longitudinally of the oscillating frame, are keyed excentrics n, which
bear on the antifriction bowls o. These excentrics have a to-and-fro rotary motion
imparted to them by suitable intermediate mechanism (the form and construction
thereof being immaterial) deriving motion from the variable driving gear, this
motion being variable in accordance with the angular extent and speed of the
expansions and contractions initiated by the variable driving gear, and so actuated
that the parallelogrammic lever system swings outwards (and therewith the
oscillating frame q connected to it, and which is always parallel to itself), away from
the other chain frame q', which remains rigid as respects the breadth of the fabric;
and this said frame q again approaches by the action of the bars h which bring
(by their spring pressure) the bowls o against the excentrics, when these latter
commence to retire, that is to say, do not press the lever system and the oscillating
frame outwards any further.
It is quite evident that the movement imparted to the oscillating frame
mechanism above described (in spite of the flexion of the spring bars, which may
be ignored in practice, the shortening being inappreciable) is exactly parallel to
the opposite frame, and the two portions of the fabric (the upper and lower) which
are subjected to the variable tension, are influenced quickly and uniformly, that is
to say, simultaneously, and with uniform pressure, a result hitherto unattainable
by existing machinery, as the movement of the oscillating frame resulted in more
or less straining and tearing of the fabric, by reason of the unequal and variable
tension put upon it, which evils are the more pronounced with a narrow fabric
and excessive variation, and there is also gained the following advantage, namely,
that it does away with the former clumsy and heavy apparatus, which was
unreliable, and caused the oscillating frame to jam and bind, and necessitated a
great expenditure of power, and was impracticable and non-efficient.
The improved devices for supporting and operating the oscillating frame possess
no sliding parts; the only points of friction are the stud axles, and the oscillating
frame is in no way supported on the worm shafts, as in other frames, but is wholly
independent thereof. It is provided with large spaces for the axles to pass through,
and all wear can be compensated for in the most favourable manner possible, and the
oscillating frame possesses considerable stability, and yet is capable of a high speed
of oscillation (about 80 vibrations per minute).
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
from abroad, I declare that what I claim is:-
1. In stretching and drying machines of that kind in which the diagonal
movement of the fabric is wholly produced by the unequal travel of the stretching
chains (not the chain guides), the arrangement of feed mechanism (adjustable and
converging, or parallel to the direction of the fabric's travel), consisting of con-
verging frames it and uniformly-driven chain wheels B B₁ in rear of said frames,
for the purpose of uniformly feeding the fabric to the machine.
2. In combination with the feed claimed in Claim 1 and its uniformly-driven
chain wheels, a compensating mechanism consisting of vertically sliding chain
wheels EE, adjustable by weights or tension, and having guide pulleys CD
and C¹ D¹, and vertically sliding guide pulleys HH', for receiving and feeding

page_text: onward the chains, said chains being alternately tightened and slackened by the
unequally driven chain wheels A A
3. In combination with the arrangements in the machine specified in Claims 1
and 2, the device described for moving the chain frame (g) parallel to and inde-
pendent of the opposite chain frame (g), by which movement an equal compensation
for the stretching of the upper and lower travel of the fabric is effected."
Dated this 16th day of April 1898.