FIELD OF INVENTION
The present invention relates to an improved JIG adaptable to a tensile testing
machine for conducting tensile testing of welded rebars.
BACKGROUND OF INVENTION
In any tensile testing machine, a test specimen is held between the two jaws of
the machine and then the jaws are pulled from one another. The load required
to break the specimen is measured and determined as the strength of that
specimen. However, it is not possible to hold a welded rebar sample (Figure 1)
into the jaws of a standard tensile machine because, in that case the load will fall
on the rebar and not on the weld. The strength value which obtained from the
test does not give the strength of the weld but of the base rebars. This type of
welded rebar is required to make the cages used for reinforcement in different
concrete casting e.g. Columns, Beams. So far any proven method for such
testing is neither known to be practiced, nor available in patent/non-patent
literature on this technical field.
OBJECT OF INVENTION
It is therefore an object of the invention to propose an improved JIG adaptable
to a tensile testing machine for testing of welded rebars.

SUMMARY OF INVENTION
Accordingly, there is provided an improved JIG adaptable to a tensile testing
machine for conducting tensile test of a plurality sized welded rebars, comprising
a base block having a threaded through hole on upper face, and two side faces;
a holder comprising a first end and a second end, the first end having a
threaded portion matching with the threaded hole of the base block so as to
releasably fix the holder on the base block, the second end of the holder being
attached to the jaws of the testing machine; a side plate having a first side and
a second side, the first side comprises at least three holes enabling the side
plate to be fixed to the base block through correspondingly sized identical
number of holes configured thereon , the second side of the side plate having a
single hole with a size corresponding to that of a combined welded rebar under
testing; wherein the center of the single hole is configured with an eccentricity
corresponding to that of the combined welded rebar.
The JIG has been primarily developed for assessing the strength of a welded
rebar. The unique fixture is capable of tensile testing of combined welded rebars
of any size by only changing the side plate of the JIG.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - Shows one each sample of a welded rebar and a Rebar cage.
Figure 2 - Shows an improved JIG in assembled state for tensile testing of a
plurality sized welded rebar in a known tensile testing machine
according to the invention.

Figure 3(a) - Shows respectively a holder, a base plate, and a side plate of the
JIG of the invention.
Figure 4 - Shows an improved JIG of the invention mounted on a known tensile
testing machine in a test mode of a welded rebar.
DETAIL DESCRIPTION OF THE INVENTION
As shown in figures 2 and 3, the improved JIG (J) comprises a base block (1), a
side plate (2), and a holder (3). The holder (3) has a threaded end (5). The
threaded end (3a) of the holder (3) is fixed with the base block (1) and other
portion 3(b) is fixed on the machine jaw (5) during tensile testing. The holder (3)
is made of mild steel so as to protect the jaw surface from erosion. The holder
(3) is threaded to ensure interchangeability whenever required. The base block
(1) is made of mild steel. The upper face of the block (1) has a through hole (6)
with thread (6) to hold the holder (3). The two side faces of the base block (1)
are threaded upto a depth of around 15 mm. Each face of the base block (1)
comprises at least three holes (7) for holding the two side plates (2). The side
plates (2) each comprises correspondingly sized at least three holes (8) by which
the side plates (2) are fixed to the base block (1). Another side of the side plate
(2) has a single hole (9). The size of the single hole (9) depends upon the size of
a rebar (10) to be tested. For example, to test a 16mm diameter rebar (10), the
size of the hole (9) can be 16 mm. The centre of this hole (9) is eccentric from
the centre of the base plate (1). This is to keep the weld in centerline. The
amount of eccentricity of the single hole (9) depends upon the rebar combination
to be tested. Figure 4 shows that the JIG (J) is in operation. To test different
diameter of rebars (10), only the side plate (2) is to be correspondingly replaced.

WE CLAIM :
1. An improved JIG adaptable to a tensile testing machine for conducting
tensile test of a plurality sized welded rebars, comprising:
a base block (1) having a threaded through hole (6), an upper face,
and two side faces;
a holder (3) comprising a first end and a second end, the first end
having a threaded portion matching with the threaded hole (6) of the
base block (1) so as to releasably fix the holder (3) on the base block
(1), the second end of the holder (3) being attached to the jaws (5) of
the testing machine;
a slide plate (2) having a first side and a second side, the first side
comprises at least three holes (7) enabling the side plate (2) to be
fixed to the base block (1) through correspondingly sized identical
number of holes configured thereon (1), the second side of the side
plate (2) having a single hole (9) with a size corresponding to that of a
combined welded rebar (10) under testing;
wherein the center of the single hole (9) is configured with an
eccentricity corresponding to that of the combined welded rebar (10).

2. The JIG as claimed in claim 1, wherein the side plate (2) is
interchangeable, and wherein the side plate (2) is selected
corresponding to the diameter of the combined welded rebar (10) to
be tested.
3. An improved JIG adaptable to a tensile testing machine for conducting
tensile test of a plurality sized welded rebars, as substantially described
and illustrated herein with reference to the accompanying drawings.

The invention relates to an improved JIG adaptable to a tensile testing machine
for conducting tensile test of a plurality sized welded rebars, comprising: a base
block (1) having a threaded through hole (6), an upper face, and two side faces;
a holder (3) comprising a first end and a second end, the first end having a
threaded portion matching with the threaded hole (6) of the base block (1) so as
to releasably fix the holder (3) on the base block (1), the second end of the
holder (3) being attached to the jaws (5) of the testing machine; a slide plate (2)
having a first side and a second side, the first side comprises at least three holes
(7) enabling the side plate (2) to be fixed to the base block (1) through
correspondingly sized identical number of holes configured thereon (1), the
second side of the side plate (2) having a single hole (9) with a size
corresponding to that of a combined welded rebar (10) under testing; wherein
the center of the single hole (9) is configured with an eccentricity corresponding
to that of the combined welded rebar (10).