AN IMPROVED APPARATUS FOR TESTING THE STRENGTH OF CLOTH AND OTHER TEXTILE FABRICS
Year: 1877

page_text: LETTERS PATENT to Gerard Wenzeslaus von Nawrocki, of the Firm of J.
Brandt and G. W. von Nawrocki, Civil Engineers and Patent Agents, of No. 2,
Koch Strasse, Berlin, in the German Empire, for the Invention of "AN
IMPROVED APPARATUS FOR TESTING THE STRENGTH OF CLOTH AND OTHER
TEXTILE FABRICS." A communication by Hermann Ellers, of Rostock, in the
German Empire.
Sealed the 19th February 1878, and dated the 29th August 1877.
L
PROVISIONAL SPECIFICATION left by the said Gerard Wenzeslaus von
Nawrocki at the Office of the Commissioners of Patents on the 29th August
1877.
:
GERARD WENZESLAUS VON NAWROCKI, of the Firm of J. Brandt and G. W. von
Nawrocki, Civil Engineers and Patent Agents, of No. 2, Koch Strasse, Berlin, in
the German Empire. "AN IMPROVED APPARATUS FOR TESTING THE STRENGTH OF
CLOTH AND OTHER TEXTILE FABRICS." [A communication by Hermann Ehlers, of
Rostock, in the German Empire.]
The present Invention has reference to an apparatus for testing the tensile
strength of cloth and other textile fabrics by subjecting it to the action of a weight
sufficient to tear asunder the threads or fibres. For this purpose a piece of cloth of
definite dimensions is placed between two pairs of nipping jaws, which by means to
be presently described are made to hold the cloth firmly at points a definite distance
apart.
:
Each jaw consists of two separate plates, one of which has an eye by which it is
suspended, and two steady pins which fit into holes in the second plate so as to
insure their accurate juxtaposition. The second plate has a screw which screws
into a threaded hole into the first plate, so as to press them firmly together, and
thus hold the cloth securely, this being placed between two projecting or nipping
edges thereon that are by preference serrated.
To insure the perfect holding of the jaws a small piece of the cloth to be tested
is placed between the rear ends of the plates, so as to maintain the plates in a
parallel position.

page_text: In order to insure the two pairs of jaws nipping the cloth at a definite distance
apart a plate is provided having two recesses corresponding with the configuration
of the nipping jaws, and before nipping the cloth the two jaws are placed in these
recesses, whereby they are held a definite distance apart while the piece of cloth is
inserted between them and secured. The one pair of jaws is then suspended from a
handle held by the operator, while to the other end is suspended a scale, upon which
are placed the weights for testing.
To prevent the scale with the weights from falling on the ground when the cloth
tears it is connected to the handle by a slack cord or chain.
A metal template is provided of the exact size of the piece of cloth to be used in
testing, which is placed on the cloth, and this is then cut to shape. By this means
the exact uniformity in the size of the pieces of cloth required for obtaining accurate
comparative results is insured.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Gerard Wenzeslaus von Nawrocki in the Great Seal Patent Office
on the 27th February 1878.
GERARD WENZESLAUS VON NAWROCKI, of the Firm of J. Brandt and G. W. von
Nawrocki, Civil Engineers and Patent Agents, of No. 2, Koch Strasse, Berlin, in the
German Empire. "AN IMPROVED APPARATUS FOR TESTING THE STRENGTH OF
CLOTH AND OTHER TEXTILE FABRICS." A communication by Hermann Ehlers, of
Rostock, in the German Empire.
The present Invention bas reference to an apparatus for testing the tensile
strength of cloth and other textile fabrics by subjecting it to the action of a weight
sufficient to tear asunder the threads or fibres. For this purpose a piece of cloth of
definite dimensions is placed between two pairs of nipping jaws, which by means to
be presently described are made to hold the cloth firmly at points a definite distance
apart.
Each jaw consists of two separate plates, one of which has an eye by which it is
suspended; and two steady pins which fit into holes in the second plate so as to
insure their accurate juxtaposition. The second plate has a screw which screws
into a threaded hole in the first plate, so as to press them firmly together, and thus
hold the cloth securely, this being placed between two projecting nipping edges
thereon that are by preference serrated.
To insure the perfect holding of the jaws a small piece of the cloth to be tested is
placed between the rear ends of the plates, so as to maintain the plates in a parallel
position.
In order to insure the two pairs of jaws nipping the cloth at a definite distance
apart a plate is provided having two recesses, corresponding with the configuration
of the nipping jaws, and before nipping the cloth the two jaws are placed in these
recesses, whereby they are held a definite distance apart while the piece of cloth is
inserted between them and secured. The one pair of jaws is then suspended from a
bandle held by the operator, while to the other end is suspended a scale, upon which
are placed the weights for testing.

page_text: To prevent the scale with the weights from falling on the ground when the cloth
tears it is connected to the handle by a slack cord or chain.
A metal template is provided of the exact size of the piece of cloth to be used in
testing, which is placed on the cloth, and this is then cut to its shape. By this
means the exact uniformity in the size of the pieces of cloth required for obtaining
accurate comparative results is insured.
Fig. 1 shews an elevation of the before-described apparatus.
Figs. 2 to 9 shew detached details thereof, and of appliances used in connection
therewith.
By means of this apparatus the strength either of the warp or of the shoot of a
piece of fabric may be tested, the piece being cut accordingly, so as when inserted
between the two pairs of nipping jaws A, A', to have either the warp thread or the
shoot running in a vertical direction. Each pair of jaws consists of a plate a, Fig. 3,
having an eye g, by which it is suspended, and of a plate b, Fig. 4, which is guided
by two pins c, c, and pressed against a by a thumbscrew d. The nipping surfaces
of the jaws are roughened, and a piece of cloth of the same substance as that to be
tested is inserted between their other ends at f. The pair of jaws A are suspended
from the handle B, which is held in the hand, and to A¹ is attached a scale to be
loaded with the required weights for testing.
For testing the cloth the template shewn in front and side view at Fig. 9 is
placed on the cloth, and a piece is cut to its exact shape; the jaws a are then placed
in the recesses of the gauge plate D, shewn in plan and section at Fig. 5, which
insures their being exact uniform distance apart, and the piece of cloth having
been placed upon them the jaws b are then fixed in position, as shewn in plan and
side view at Figs. 6 and 7, being screwed up by the key, Fig. 8, so as to nip the
cloth firmly between them. The jaws, with the cloth between then, are then
attached respectively to the handle and the scale, and the latter is loaded until the
fabric is torn, the strength of the latter being thus ascertained by the weight it will
bear before tearing.
The scale is attached to the handle by a cord F, so as to prevent it from falling
to the ground on the tearing of the fabric.
Having thus described the nature of this Invention, and in what inanner the
same is to be performed, as communicated to mic, I claim, the use of apparatus for
testing the strength of cloth and other textile fabrics, wherein a piece of cloth is
secured between two pairs of nipping jaws while these are held a definite distance
apart by a gauge plate, and is then subjected to strain by suspending weights to the
one pair of jaws, substantially as herein described.
In witness whereof, I, the said Gerard Wenzeslaus von Nawrocki, have here-
unto set my hand and seal, this Twenty-fifth day of February, in the year of
our Lord One thousand eight hundred and seventy-eight.
GERARD WENZESLAUS V. NAWROCKI. (L.S.)