U.S. patent number 3,641,807 [Application Number 05/013,409] was granted by the patent office on 1972-02-15 for traffic machine for carpets.
This patent grant is currently assigned to Monsanto Company. Invention is credited to Gene A. Brooks.
United States Patent |
3,641,807 |
Brooks |
February 15, 1972 |
TRAFFIC MACHINE FOR CARPETS
Abstract
A traffic machine for testing carpets to simulate the effect of
flat floor wear thereon, said machine having a roller assembly
comprising a beam pivotally connected to a lever, the beam being
adapted to pivot on an axis substantially parallel to the direction
assumed by the path of travel of a table, a plurality of rollers
connected to said beam, the rollers being adapted to move
substantially perpendicular to the direction of travel of the
table.
Inventors: |
Brooks; Gene A. (Decatur,
AL) |
Assignee: |
Monsanto Company (St. Louis,
MO)
|
Family
ID: |
21759822 |
Appl.
No.: |
05/013,409 |
Filed: |
February 24, 1970 |
Current U.S.
Class: |
73/7 |
Current CPC
Class: |
G01N
3/56 (20130101); G01N 33/36 (20130101) |
Current International
Class: |
G01N
3/56 (20060101); G01N 33/36 (20060101); G01n
031/56 () |
Field of
Search: |
;73/7 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Publ. "Rollers to Test Carpet Wear on Materials" by Popular Science
Monthly. Nov. 1931, p. 34, Q-1-P8. .
Publ. "New Apparatus for Friction Measurement" by Willson et al.
Inst. Soc. of Am. Journal Vol. 3, No. 7, July 1956. .
Publ. "New Wear Testing Method Saves to Time" by Shuler. Dow
Corning Corp. Form No. 06-084, May 1967, pp. 1-4..
|
Primary Examiner: Prince; Louis R.
Assistant Examiner: Yasich; Daniel M.
Claims
I claim:
1. An apparatus for testing wear resistance properties of a test
specimen comprising:
a. a frame,
b. a table for supporting the test specimen, said table being
movably mounted on the frame;
c. means for reciprocating said table at a predetermined rate;
d. a lever mounted pivotally to the frame, a roller assembly
mounted on said lever, said assembly including a beam pivotally
connected to said lever, said beam being adapted to pivot on an
axis substantially parallel to the plane of movement of the table,
a plurality of rollers connected to the beam for engaging said test
specimen, the rollers being adapted to be moved in a direction
substantially perpendicular to the plane of movement of the table;
and
e. means applied to said lever for exerting a uniform force upon
said assembly during the reciprocation of said table, and, thus,
the test specimen supported thereon.
Description
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for testing wear resistance
of floor covering and the like. In particular, the subject
invention relates to a laboratory method and apparatus for testing
carpet to simulate the effect of flat floor wear thereon.
A number of tests such as tensile strength, elongation, abrasion
and compression resistance are made upon surface covering to
determine the wearing qualities of textile fabrics and related
materials. Compression resistance or thickness retention is very
important since it is an index to fabric durability and
appearance.
Various attempts have been made to develop a laboratory test
apparatus to duplicate the wear received by a carpet laid in
substantially flat position and subjected to floor traffic. In
practice many of the conventional wear testers are not fully
satisfactory since test data obtained therefrom cannot be
correlated with actual wear data.
As would be apparent the method of actually placing carpet samples
under a high amount of floor traffic has disadvantages inherent
therein, the most objectionable being, the variability of carpet
wear from different steps, lack of control over environmental
conditions such as humidity and temperature, the number of samples
which can be tested and the time required for obtaining data. In
view of the foregoing discussion, it would be highly desirable to
have an apparatus capable of performing a simulated wear test and
predict how well a carpet will perform in a flat floor
installation.
SUMMARY OF THE INVENTION
In evaluation of carpets a number of factors are carefully
considered to determine how well a carpet retains its original
appearance, thickness and compression properties. Although a number
of devices are in current use they often suffer from a lack of
positive correlation between actual floor traffic to laboratory
traffic simulated by a particular device. A number of factors
effect variation in attempting to relate actual specimens to
simulated specimens, some factors being the type and kind of
footwear employed, average weight of individuals walking over the
test specimen, variation in soiling mixtures and the amount
thereof, etc.
Surface covering testers are limited generally to impact alone or
to impact and abrasion. The subject invention by its constant
pressure and rolling action of a novel assembly to be more fully
described hereafter serves to compress and abrade the covering
reproducing conditions of actual walking traffic. Hence, it now
becomes possible to check the wearing properties of a surface
covering to be installed, especially the compression
characteristics, without actually installing it in the environment
in which it is to be used.
It is a primary object of the subject invention to provide a method
and apparatus for simulating actual flat floor wear on a test
specimen in a uniform manner under controlled environmental
conditions.
It is another major object of the invention to provide a method and
apparatus to give carpet specimens accelerated wear for obtaining
test data in a minimum time period.
Another object of this invention is to provide a method and
apparatus for accelerated wearing of carpet specimens whereby the
thickness retention of the carpet specimen is directly correlated
with actual floor traffic. Other objects and advantages of the
present invention will become apparent from the disclosure.
In accordance with the subject invention, it has been discovered
that the performance of carpets laid on a flat floor can be
accurately predicted from test data recorded in a matter of hours
rather than in several weeks normally required by actual field
studies for carpet fabricated from natural and synthetic
fibers.
A preferred embodiment for accomplishing the objects of the present
invention contemplates a frame, a table movably mounted on the
frame, the assembly including a plurality of roller members
arranged in a spaced-apart relationship, means for exerting a
uniform force upon said assembly during the reciprocation of said
table and thus, a specimen supported thereon.
In order to better understand the construction and use of this
novel testing device, it will be described in relation to its use
for simulating a condition which a carpet encounters when installed
on a flat surface face. It is also to be understood that various
other uses may be found for this novel apparatus. For example, it
could be utilized to test other surface covering such as linoleum,
tile, asphalt, concrete, wood and others. Furthermore, the
apparatus may be used to simulate conditions wherever impact and
abrasion forces exist. Other uses will be readily apparent to those
skilled in the art.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a prospective view of the apparatus of this invention
having portions of the apparatus cut away to show selected interior
components, and
FIG. 2 is a view of the roller assembly of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the embodiment illustrated in the drawing and, in particular,
FIG. 1 a frame 15 supports a motor 18 having a shaft 22 extending
into a gearbox 23 which translates the drive motion of said motor
18 to a plate 24 having a number of arms 25 around the periphery
thereof. Adjacent the gearbox 23 is a counter 32 having a spoked
actuating element in mesh with arms 25 of a plate 24. A link 21 is
attached pivotally to the plate 24, the other end of which is
pinned to the base of a table 20 to permit oscillation of the table
20. The upper surface of table 20 is employed to hold in place a
test specimen via clamps 27. Table 20 has wheels 34 and 34' along
one side between which a handle 35 is secured. The wheels 34 and
34' roll along a portion of the frame 15 and support one side of
the table 20 while a pair of guide sleeves 29 and 29' secured to
and located along the opposite side of the table 20 are slidably
attached to a guide rod 28. Pivotally attached to the frame 15 is a
lever 17 to which is attached at its free end weight 16.
A principal assembly bar 10 traverses the lever 17 and is attached
thereto. Pivotally secured to the bar 10 is the pressure roller
assembly designated generally as 9 and more fully shown in FIG. 2
herein. The assembly includes a key beam 11 the terminal portions
of which are pivotally attached to a U-shaped structure or
intermediate support 30, each arm of which pivotally couples at
least one roller housing 13. The housing 13 of the assembly support
a plurality of rollers 14, the longitudinal axes of which are
parallel to that of the principal assembly bar 10 and at right
angle to the direction of movement at table 20.
As illustrated, an array of eight rollers (2 inches in diameter and
11/8 inches wide) made of hard rubber are arranged to form the
assembly. It is found that the load placed on the assembly by
setting on the lever 17 a given weight 16 presents an even
distribution over all the rollers 14, regardless of the
irregularities of the surface on which the wheels are running.
The operation of the traffic machine is thus readily apparent. The
free end of the lever 17 is lifted and a test specimen 36 is
secured to the table 20 by means of clamps 27. The lever 17 is
lowered into position whereby the roller assembly 9 is placed into
contact with the test specimen 35. Weights 16 are placed upon the
lever 17 to present a given load upon the specimen to be tested.
The motor 18 drives the plate 24 which in turn moves link 21 to
reciprocate table 20 upon the frame 15. Upon rotation of plate 24
the number of revolutions is determined by the counter 32.
The load exerted on the carpet may be varied over a wide range,
preferably from 15 to 500 pounds total load. Thus, the load or
pressure on the carpet may be varied from less than 2 pounds per
inch of roller up to more than 55 pounds per inch of roller.
Carpet specimens are first measured for thickness and compression
and then exposed to the apparatus herein disclosed. After allowing
the specimen to recover they are measured for thickness and
compression and the percent thickness retained and percent residual
compression can be calculated therefrom for various traffic levels
and loads.
Carpet thickness denotes the overall thickness of carpet as
measured under pressure 0.1 p.s.i. whereas carpet compression
denotes the difference between carpet thickness when measured under
pressure of 1.0 p.s.i. and that measured under 9.0 p.s.i.
It can be appreciated that the wearing action of the carpet
specimen is applied by the plurality of rollers and that the
pressure upon the specimen can be maintained constant throughout
the test period or can be varied momentarily or over different
periods by regulation of the amount of weight placed upon the
lever. As illustrated herein, the lever can be subjected to more
pressure by the addition or subtraction of weights placed thereon.
It is understood that other means for placing pressure of the
specimen would become apparent to one skilled in the art as by
employing a pressure control valve using gas or fluid therein.
It can also be seen from the foregoing that specimens may be
withdrawn easily from the apparatus for measurements to determine
by laboratory instruments the degree of wear at different stages of
the test period.
Although the specimen may be subjected to various temperatures and
conditions specimens are normally maintained at ambient temperature
and conditions. At any rate, to determine the optimum
characteristics of a particular carpet it is generally necessary to
subject it to testing in an environment which duplicates as closely
as possible actual environmental conditions.
The rate of reciprocation can be varied over a wide range.
Preferably a rate of 26 cycles per minute under pressure of 15 to
25 pounds per inch of roller is adequate.
Speeds and sizes of materials used can be varied, but for testing
various types of carpet, certain combinations are more advantageous
than others in that they appreciably wear the specimen within a
reasonable time and yet do not wear it so rapidly that it becomes
difficult to observe and measure small differences in the
specimen.
From the foregoing it is apparent that wearability produced by this
apparatus is uniform and reliable for accurately predicting future
performance of carpets and other floor coverings.
* * * * *