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Патент USA US3083581

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April 2, 1963
E. P. CARTER
3,083,564
TEXTILE IMPACT TESTER
Filed Feb. 19, 1960
2 Sheets~$hyeet 1
INVENTOR.
ERNEST /? CARTER
' Ma
ATTORNEY
April 2, 1963
E. P. CARTER
3,083,564
TEXTILE IMPACT TESTER
Filed Feb. 19, 1960
2 Sheets-Sheet 2
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TEMPERATURE
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INVENTOR.
ERNEST R CARTER
BYKM
ATTORNEY
United States Patent O?tice
1
3,683,564
Patented Apr. 2, 1963
2
dulum after passing through the equilibrium position at
3,833,554
TEXTELE EME’AET TESTER
Ernest P. Carter, Decatur, Ala, amigner, by mesne as
signments, tdMonsanto Chemical Company, a corpo
ration of Delaware
Filed Feb. 19, 1960, Ser. No. 9,86?
' 4i {Balm-s.
(til. 73-42)
the bottom of its swing without a test specimen in place
against the instance where a test specimen is in place
and intelposed as an obstruction in the swing path of
the pendulum. Thus, the energy absorbed from the free
falling pendulum in effecting rupture of the test specie
men is given by the relation
V=MXg (cos 0—cos 01)
This invention relates to an apparatus and method
for measuring the impact strength of textile materials. 10 where M represents the total pendulum mass, X is the
distance from the axis of suspension of the pendulum to
By impact strength, as used herein, there is meant that
property which enables a given textile matereial to with—
its center of gravity, where g is the acceleration of grav
stand or resist the stresses of “shock loading.”
ity, 0 is the angle of de?ection of the pendulum from
While there are devices and procedures for evaluating
the vertical after rupturing the test specimen, and H1
the strength property of textile materials, they are not 15 is the angle of de?ection of the free-falling pendulum
reliable for use in measuring the ability to resist impact
Without a test specimen in place. Error due to extra
forces. Although the strength property is involved in
neous frictional losses (bearings, wind resistance, etc.)
establishing the level of resistance to the impact process,
is eliminated from consideration on the plausible as
the conditions of impact are different from those which
sumption that these small losses are constant both with
prevail in the usual strength tests. For example, con
and Without a test specimen in place and therefore can
ventional strength tests are conducted with relatively
cel out.
low loading rates while the impact process is character
As is clearly evident, it is essential that angular de
ized by an extremely fast loading rate. It is primarily for
?ections of the'pendulum be capable of a very precise
this reason that standard strength tests cannot properly be
measurement since comparative differences Will always
employed for measuring impact strength in that the load 25 be small in view or“ the low energy requirement for break
which textile yarns and cords are able to sustain with
ing a single ?lament test specimen. Hence, a particularly
out breaking varies with the rate of load application.
important feature of the present invention, as will be
Moreover, the order or rank of di?fering textile materials
described hereinafter, is the provision of highly sensitive
based on load sustaining ability has been found to differ
indicating means for accurately measuring the arc
30 traversed by the pendulum as it swings from free-fall in
with a change in the rate of loading.
Because textile materials, such as nylon, rayon and
a test situation.
the like have been employed with increasing frequency
Since it is desirable in some instances to have the test
in the fabrication of products where resistance to “shock
specimen at a controlled elevated temperature when ap
loading” is an essential service requirement, a need has
plying the impact force, means are provided for accom
developed for means to accurately evaluate the ability 35 plishing this objective. The capability for conducting the
of textiles to withstand these stresses. That is, it has
impact test at an elevated temperature is particularly
become necessary to properly evaluate the impact re
important when testing textile tire cord in that the pneu
sistance of textiles which are contemplated for use in
matic tires of motor vehicles experience temepratures of
the fabrication of such products as the structural ele
140° C. or better during service, and it has been found
40
ments of pneumatic tires, parachute guide lines, tow
ropes, various types of netting and the like.
Accordingly, it is a primary object of this invention to
provide a means for accurately evaluating the impact
strength of textile materials.
Thus, in order to obtain test data having a closer corre
laion with actual service experience, it is necessary to
simulate the temperatures encountered in service.
It is a further object of this invention to provide a de
vice capable of applying a “shock load” to a textile test
vention are described in greater detail in the discussion
specimen, sufficient to break it, and to indicate the en
ergy required to effect the break or rupture.
Other objects and advantages of the present invention
will become ‘apparent in the description as given herein
after.
in general, the objects of this invention are accom
plished by a device having means provided for (l) sus
pending a textile ?lament at a predetermined tension,
(2) applying an impact force to the suspended and ten
sioned test specimen su?icient to effect the rupture there
that elevated temperaures a?ect impact performance.
The above-noted and other elements of‘ the present in
which follows wherein reference is made to the accom
panying drawing which illustrates a preferred embodi
ment. Because the drawing is presented merely to illus
50 trate a particular embodiment of this invention, it should
in no way be considered as limitative.
In the drawing,
FIGURE 1 is a perspective view of a preferred em
bodiment of the invention illustrating the general lay
out of that part of the apparatus which includes the
pendulum and the means for suspending the test speci~
men at a predetermined tension.
of, and (3) indicating the energy absorbed from the ap
FIGURE 2 is a schematic diagram of the various ele
ments which can be used to bring the test specimen to
An essential element of the test device is a Weighted 60 a predetermined elevated temperature.
pendulum which provides the means for shock loading
FIGURE 3 is a schematic diagram of the circuit em
the suspended test specimen. The pendulum is adapted
ployed to measure and record the angular displacement
to be released from a poised position at a predetermined
‘of the pendulum in a test situation.
angle of de?ection from the vertical such that it will
Referring to the drawing, the numeral 10 designates
strike the test specimen laterally at the bottom of its
a base member. Extending upwardly from the base It)
swing in free-fall with su?icient force to break it. The
is a supporting standard 11 having a horizontal exten
relative ‘amount of kinetic energy absorbed from the
sion 13 at the end of which there is mounted a housing
plied force to accomplish this rupture.
free-falling pendulum in effecting the break or rupture
16. Protruding out longitudinally from housing 16 is
of the test specimen affords a measure of the impact re
a shaft 15 which is mounted on ball hearings to permit
free rotation thereof. Pivotally connected to shaft 15
is a weighted pendulum l2.
sistance property.
The amount of energy absorbed from the swinging
pendulum in causing the test ?lament to break is deter
mined by comparing the angular de?ection of the pen
Pendulum 12 is held in poised position at a prede
termined angle from the vertical by a spring loaded
-~
3,083,554.
1i
3
pin 21.
Pin 21 is horizontally mounted at the upper
end of slotted bar 19 which in turn is secured within
bracket. support 26 along with disc 18 by means of
Wing nut 22. The angle at which the slotted bar it?
is positioned can be modified by loosening wing nut 22
and adjusting the bar to the desired angle. Since the
slotted bar 1? supports the pin 21 against which the
pendulum rests when held in poised position, any change
in the angle at which the bar is held will cause a like
change in the initial deflection of the pendulum, i.e.
the angular displacement from the vertical'at which
the pendulum is held prior to release for a free-fall
to both ends of the test block 24. Metal tubing or any
other ‘suitable conduit may be used to transfer compressed
air into the block from an outside source. The test block
'
is provided with hinged cover members 40 and 41 (as
shown in FIGURE 1) which also prevent heat losses from
the block.
The cover members are provided with handles
42 and 43 to facilitate the opening and closing thereof.
In order that the covermembers can be made to close
properly over clamps 25 and 26 as well as cylindrical
posts 27 and 28 which protrude above the top surface of
the test block 24, recesses such as 25a and 27a are pro<
vided in both cover members. Since it is desirable that
there be a uniform distribution of heat throughout the
Thus, the pendulum can be initially poised at
testing block when employing elevated temperatures dur
any de?ection up to 90° for differing test situations
by referring to the calibrations on disc 13 for the desired 15 ing the testing operation, the inside surfaces of block 24
and cover members 40 and 4-1 are preferably lined with
angle and adjusting bar v19 accordingly. The mecha
a heat conducting material such as aluminum. it is also
nism by which the pendulum is released from its poised
desirable that the block and cover members the insulated
position to swing in free-fall is by the longitudinal dis
with asbestos or other insulating material to further mini
‘ placement of that part of pin 21upon which the pendu
mize loss of heat therefrom.
lum rests. Since the pin 21 is spring loaded, this is
swing.
accomplished by manually forcing the pin in a direction
opposing the spring bias.
Mounted in the test ‘block 24 are test specimen clamps
25 and 26, positioned between clamps 25 and 26 and in
alignment therewith are cylindrical posts 27 and 28.
These cylindrical structures provide smooth, rounded sur
faces for the test ?lament to bend against upon receiving
the pendulum impact and prevent tearing of the test speci
men which might other-Wise occur if bending took place
at the sharp clamp surfaces. Between cylindrical posts
27 and 23 there is a groove 29 in the test block 24 which
extends across the width thereof. The purpose of this
groove is to provide a means for the pendulum to pass
through the block 24 while swinging ‘from free-fall.
In alignment with clamps 25 and as but positioned out
side the test block 24, there is shown a means for impart
ing predetermined tension to the test ?lament 30 which in
cludes a supporting base 31 having an upright 32 extend—
ing vertically therefrom. Secured to the upper end of the
upright 32 and extending out horizontally therefrom is a
stationary shaft 33 having a sleeve 34 rotatably mounted
thereon. Rigidly attached to sleeve 34 and adapted to
As explained hereinabove, the impact strength of textile
materials is evaluated in ‘accordance with the procedure
of this invention by determining the amount of energy
absorbed from the'free-falling pendulum in effecting a
rupture of the test specimen, which is generally a single
textile ?lament. In determining the energy absorbed.
from the pendulum to break the test ?lament, it is neces
sary that an accurate measurement of the angular deflec
tion experienced by the pendulum in each test run he
obtained.
Since the pendulum :12. is pivotally connected to rotat
able shaft 15, this shaft is caused to rotate in response
to the pendulum swing. The degree or extent or rotation
will, of course, correspond directly to the angular dis
placement or the arc traversed by the pendulum as it is
allowed to ‘swing from free-fallin a test situation. Thus,
the angular displacement of the pendulum can be readily
ascertained ‘from a measurement of the torque produced
in shaft 15 through movement of the pendulum 12. This
measurement is obtained in the present invention by em
rploying a low-torque potentiometer which is connected
to rotatable shaft 15 and accurately divides an electric
current vor voltage inproportion to the shaft rotation.
The potentiometer is mounted in the housing 16 shown
pivot in opposition to each other are lever arms 3-5’ and
36. Attached to the free end of lever arm 35. is a grooved
vmember 37 to which one end of the test specimen is 45 in FIGURE 1 as is shaft 15 to which it is connected. It
is necessary to employ a potentiometer having a low tor
secured. That is, one end of the test specimen is wound
que requirement because of the light radial loads to which
in the groove of member 37 and secured therein by
tightening lock nut 33. An adjustable counter-weight 39 a this instrumentgmust respond. However, any commer
cially available potentiometer having a torque require
is attached to lever arm 3d and is adapted for positioning
anywhere along the length thereof. Thus, the tension 50 ment in the range of from about 0.003 to 0.008 o'z./inch
can be suitably employed.
Reference is made to FIGURE 3 of the drawing where
a‘schematic diagram is shown of the circuit contemplated
vAs has been indicated, it is often desirable that the test
for indicating and recording the rotation of the shaft to
specimen ‘be at a controlled, elevated temperature while
conducting the impact strength test, with such condition 55 which the pendulum 12 is connected, ‘such as shaft 15 in
on the test specimen can be controlled by position adjust
ment of counter-weight 39 on lever arm 36.
being particularly desirable when testing textile materials
which are contemplated for a tire cord end use.
Refer
FIGURE 1.
There is shown a power source 53 and a
standard potentiometer circuit including a coil 54 and
coil tap 55 connected thereto. The coil tap 55 is caused
ence is made to the schematic diagram of FIGURE 2
to move and divide the current or voltage in response to
where a suitable ‘arrangement of means for heating and
for controlling the temperature of the test block are illus 60 the swinging movement of pendulum 12. which is con
nected to the coil tap through a horizontal rotatable shaft,
trated. Thus, there is shown a heating means 51 and
such
as shaft 15, as shown in FTGURE 1. This induces
temperature control means 52 connected to each other
an
electrical
signal in the potentiometer circuit which
with both being in turn connected to the test block 24- at
passes to an ampli?er 56 and ?nally to an electrical
different points thereon. The heating means may com
57. The amplifier used may be any of the stand
prise any suitable, commercially available, electrically 65 recorder
ard
types
while the electrical recorder may, for example,
operated heating device. The heat source may be posi
be a strip recorder or any other type conventionally used
tioned outside the test block or alternatively electrical
for such purpose.
heating elements can be insertedwithin the block. The
The procedure generally followed when employing the
temperature control means employed can be any of the
well-known devices normally used for this purpose, such 70 impact testing device :of this invention is to ?rst adjust
the pendulum holding means to obtain the desired initial
as an electrically'operated standard bridge type tempera
angular de?ection of the pendulum before it is released
ture control. In order to restrict entry of unheated air
for free-fall. This is accomplished by loosening wing
into the test block, air pressure is maintained therein
nut 22 ‘so that slotted bar 1% can be properly positioned
which exceeds that of the atmosphere. Thus, as is shown
in FIGURE 2, a source of compressed air 58 is connected 75 to the desired angle using the angle calibrations on disc +18
3,083,564.
5
6
as a guide. After adjustment of the pendulum holding
means, the pendulum is released from the initial de?ection
structed path, i.e., ‘without a test specimen in the swing
source and having a coil tap secured to the rotatable shaft
so that movement of the pendulum moves said coil tap,
and means for indicating the movement of the coil tap.
3. A device for testing the capacity of a textile ?lament
path, and the arc traversed is ascertained and recorded.
for resisting rupture from impact loading comprising: a
Following a determination of the angle displaced by the
pendulum when free to swing in an unobstructed path,
the test specimen is positioned in the swing path and the
vided with a central groove extending across the width
at which it is held to swing in free-fall over an unob
base, a block supported on the base, said block being pro
thereof and hinged cover members, a pair of ?lament
positioning clamps mounted within said block on opposite
10 sides of the central groove thereof, a pair of cylindrical
posts positioned within the block on either side of the
will, of course, be smaller than in the instance where the
central groove thereof and between said ?lament posi
path of the pendulum was unobstructed, since breaking
the test ?lament will consume gravitational energy. The
tioning clamps, tension regulating means mounted adja
extent of difference in the magnitude of these angles
cent said ?lament positioning clamps for maintaining a
affords the measure of impact resistance possessed by the 15 predetermined tension on said ?lament, means for main
test specimen.
taining the ?lament at an elevated predetermined tempera
angle displaced by the pendulum is again determined with
the test ?lament obstructing the swing path. This angle
It is to ‘be understood that the above-described embodi
ture, a rotatable shaft mounted above the base, a weighted
pendulum secured to the rotatable shaft and adapted to
ment of this invention is amenable to many modi?cations.
swing in a path wherein engagement is made with the
Consequently, the intent is to cover all such changes and
modi?cations which do not constitute departures from- the 20 ?lament to e?ect a rupture thereof, a releasable support
for positioning the pendulum at a predetermined angle
spirit and scope of the invention as set forth in the follow
ing appended claims.
from the vertical, an electrical power source, a potenti
I claim:
ometer connected across the power source and having a
1. A device for testing the capacity of a textile ?lament
coil tap secured to the rotatable shaft so that movement
for resisting rupture from impact loading comprising: a
of the pendulum moves said coil tap, and means for in
dicating the movement of the coil tap.
base, a block supported on the base, said block being pro
4. A device for testing the capacity of a textile ?lament
vided with a central groove extending across the width
for resisting rupture from impact loading comprising: a
thereof and hinged cover members, a pair of ?lament
positioning clamps mounted within said block on opposite
base, a block supported on the base, said block being pro
vided with a central groove extending across the width
sides of the central groove thereof, tension regulating
means mounted adjacent said ?lament positioning clamps
thereof and hinged cover members, a pair of ?lament
positioning clamps mounted within said block on opposite
for maintaining a predetermined tension on said ?lament,
means for maintaining the ?lament at an elevated pre
sides of the central groove thereof, tension regulating
means mounted adjacent with said ?lament positioning
determined temperature, a rotatable shaft mounted above
clamps for maintaining a predetermined tension on said
the base, a weighted pendulum secured to the rotatable
shaft and adapted to swing in a path wherein engagement
?lament, an electrically operated heater connected to said
block, an electrically operated temperature control device
is made with the ?lament to effect a rupture thereof, a
releasable support for positioning the pendulum at a pre
connected to said heater and to said block, ‘a source of
compressed air connected to said block, a rotatable shaft
determined angle from the vertical, an electrical power
source, a potentiometer connected across the power source 40 mounted above the base, a weighted pendulum secured
and having a coil tap secured to the rotatable shaft so
that movement of the pendulum moves said coil tap, and
means for indicating the movement of the coil tap.
2. A device for testing the capacity of a textile ?lament
to the rotatable shaft and adapted to swing in a path where
in engagement is made with the ?lament to effect a rupture
base, a block supported on the base, said block being pro
vided with a central groove extending across the width
thereof and hinged cover members, a pair of ?lament
source and having a coil tap secured to the rotatable shaft
so that movement of the pendulum moves said coil tap,
and means for indicating the movement of the coil tap.
thereof, a releasable support for positioning the pendulum
at a predetermined angle from the vertical, an electrical
for resisting rupture from impact loading comprising: a 45 power source, a potentiometer connected across the power
positioning clamps mounted within said block on opposite
sides of the central groove thereof, tension regulating 50
means mounted adjacent said ?lament positioning clamps
for maintaining a predetermined tension on said ?lament,
an electrically operated heater connected to said block,
References Cited in the ?le of this patent
UNITED STATES PATENTS
1,946,100
Norton ______________ __ Feb. 6, 1934
2,521,244
Moore ______________ .._ Sept. 5, 1950
an electrically operated temperature control device con
2,778,219
Wachter ______________ __ Jan. 22, 1957
55
nected to said heater and to said block, a rotatable shaft
OTHER REFERENCES
mounted above the base, a weighted pendulum secured to
the rotatable shaft and adapted to swing in a path wherein
Publication: Textile Research Journal, December 1953,
engagement is made with the ?lament to effect a rupture
Article by Lyons et al., pages 917-925. (Copy in 73-12.)
thereof, a releasable support for positioning the pendulum
at a predetermined angle from the vertical, an electrical
power source, a potentiometer connected across the power
6O
Publication: “Symposium on Impact Testing,” ASTM
#176 (1956), pages 134—139. (Copy in Scienti?c Li
brary TA407 A5i.)
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