"MEASURING STRAINS IN 3 AXES IN BOLTS/AXLES/STUDS/SHAFTS/LINKS BY INSTRUMENTING THEM FROM INSIDE"
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION: -
Field Of Invention
The present invention relates to the field of engineering device. More significantly, the present invention relates to measurement offerees as experienced in a BOLT's / AXLE's / STUD's and/or SHAFT'S with a secured mechanism for preventing damages to the sensing elements used on the outer surface of such DOLT's / JVXLE'S / STUD's and/or SHAFT'S or any Link used in similar configuration. In short we would be referring these members as BASS members or LfNKs, in the entire document.
Background of invention
BOLT'S /AXLE's / STUD's & SHAFT'S have been used as an essential part of machines for centuries. At first glance, these are seemingly simple and insignificant LfNKs that are in existence for centuries, and are supposed to hold things together, but just irnagine the catastrophe if they'fail in a moving train, or in a flying aircraft, or in a car or elsewhere.
Those working in the industry have witnessed much fine-tuning of BOLT's / AXLE's / STUD's & SHAFT'S during recent decades. Earlier, the strength of these members were not as fijlly defined as it is today. As the raw materials industry has become more sophisticated, the design of Shafts, bolts, studs, and axles have changed to meet changing industry needs and safety regulations.
This has necessitated the evaluation of strength of such members (BOLT's / AXLE's / STUD's and/or SHAFT'S -BASS rpembers), wherever these are intended to deployed under actual field conditions.
Strain gauges were invariably used as one of the standard method for such measurements. However, it has serious limitations that one can do so by fixing strain gauges at the outer body of BASS members by running a risk of getting them damaged even before these could yield any tangible data. In view of this, nobody could measure successfully in X, y and z direction from the same LINKs.under static or dynamic conditions.
Current methods being used with risks and drawbacks...
• Make a drill of less than 2 mm along the axis upto the desired depth of measurement and use a very low viscosity special adhesive to fill this hole along with a strain gauge. Although this method safeguarded the gauge from mechanical damage due to scrapping by other mechanical parts, yet this method needs an extra,special adhesive and extra special skills with absolutely no control over the parallelism of axes of the gauge and that of BASS members. If everything goes well this mechanism would only yield forces in axial direction only. And no information could be gathered about bending forces in this arrangement.

• If bending forces are to be measured, gauges could be fixed on the outer surface of BASS members in use. If necessary, by machining small portion of the BASS member at the center, on all 4 sides as shown in Figure-I. The 2 gauges on the opposite sides forming the one set of gauge to give bending force information (vertical direction), whereas other 2 gauges will yield information in perpendicular to first position (horizontal direction).
But protection of these gauges & wires have always been an issue as they are highly susceptible to damage and eventually loss of data / No data at all.
As such, no successful methodology could be made and deployed that could give bending strains in X and ¥ direction and simultaneously can provide strains proportional to axial tension/compression.

Gauge-4
Gauge-3
Figure-l shows the existing method to measure the bending force, BOLT IN THIS CASE, by fixing 4 gauges 90 deg. apart with their sensing axes parallel to axes of the Bolt. One pair 180 deg. apart makes for bending in one direction, and other two gauges providing bending informatioii normal to the previous direction of sensing.
Object of invention
The main object of present invention is to provide an arrangement that enables to measure simultaneously forces in X, Y and Z direction of an BASS members (BOLT'S / AXLE's / STUD's or SHAFT's) or any LINKs that is being used to join parts of a moving or non-moving machine or jig or contraption for any application and experiencing forces under static and/or dynamic conditions that need to be evaluated as part of designing or verification process of such parts during fabrication / production or aftermarket stage.
Such BOLT'S./ AXLE'S / STUD's or SHAFT'S) or any LINKs may be individual item or part of the assembly such as HUB or in a welded state such as for collapsible Steering, in whatever state or form as individual item or part of assembly.

Summaty of invention
These BASS members or any LINK, which need to be evaluated, or to be used to evaluate the parts of the machine being joined using this BASS members need to be instrumented using strain gauges for measuring strains in X, Y and Z directions. Due to the problems of damaging these strain gauges mechanically when deployed on the outer surface of the machine parts, a methodology is- devised to embed these strain gauges inside the machine parts so that we get 3 distinctively different outputs each corresponding only to one nf X, Y or Z direction of foices.
By measurement of forces in orthogonal directions, perpendicular to each other, we can call:
Z direction along the axis of these BOLT's / AXLE's / STUD's or SHAFT'S) or any LINKs
X and Y directions are perpendicular to Z directions and are at 90 degree tn each other, that is in a plane perpendicular
to the axis of BOLT's / AXLE's / STUD's or SPL\FT's) or any LINKs.

Figure 2 shows the arrangement devised by Shivalik Hills Development Pvt. Ltd, in which, in a small cylindrical metal part assembly is machined in such a way to create two perpendicular surfaces as shown 12 and 13. On these upto 8 or less strain gauges (4,5), (6,7), (8,9) and (10,11) in upto 4 groups are installed. Gauges 4, S and 8, 9 will be sensitive for one direction of bending force and other 4 gauges will be sensitive at 90 degree to first set of 4 gauges. When this assembly is inserted in a small hole in the bolt and rested at a location so as to coincide the center of bolt or BASS member to the center of the proposed assembly.

Detail description of invention
The present invention incorporates a tiny capsule which has two flat members perpendicular' to each other, one sensitive to X direction bending only and another to Y direction of bending only but simultaneously impervious to cross bending. It greatly increases the ease of measurement. For each direction of X or Y, we use strain gauges, one for tensile force and another for compressive force measurement. This capsule is inserted in a tiny hole done along the axis upto the depth as per length of the specimen. We have to ensure the alignment of the center of the speciiiieii lo that of capsule. These specimen may differ in the following manner:
1. In diameter
2. In length
3. In description by way of its construction
a. It could be designed as bolt
b. It could be designed as Stud
c. It could be designed as shaft
d. It could be designed as Axle
e. It could be designed as a Link
f. Or any other member designed to join machine parts.
For now for the ease of understanding Lets call them SPECIMEN under consideration or BASS members. Fixing strain gauges to measure strain in X, Y and Z direction is called INSTRUMENTING OF SUCH SPECIMEN.
Objective of Instrumenting the Specimen / BASS members:
• To evaluate the design of SUCH SPECIMEN itself could be the objective and thus instrument it.
• Validation of design could be the objective of instrumenting a specimen(s).
• The design of those machine parts which are being joined by these SPECIMEN(S).
• . The validation of design of those machine parts which are being joined by these SPECIiVrEN(S).
The diameter and/or length of these capsules will change depending upon the dimensions of specimen. Z-Direction
For measurement of the strain in Z direction, a gauge is fixed on the inner wall of the drilled surface. The existing method is to insert the gauge in a hole filled with low viscosity adhesive. The strains of the tjody of the specimen were invariably different and more than the measured value from the inserted gauges. Part of the force being absorbed by the elasticity of the adhesive. X, Y- Directions
Referring to Figure-2: 1, 2 and 3 are collars in which collar 2 is positioned at the center of the specimen. When specimen is subjected to vertical loading, 2 with respect 1 and 3 will sag thus that specimen will bend like bow because of which 4 and 6, strain gauges, will experience compressive stress and 5 and 7 will experience tensile stress. For the purpose of accuracy and improvement in cross sensitivity, we add gauges 8,9,10 and II. Elements 12 and 13 are perpendicular to each other,

We claim that.
.A. for measurement of strains in X and Y directions, the fabrication of a miniature capsule with two flexures , say X and Y, having surfaces perpendicular to each other but both sensitive to bending only in one direction independently, in X or Y, the bending being normal to its axis so as to enable measurement of the strain in X and Y direction of bending, respective to the perpendicular surfaces catering to measurement in X and Y direction Strain gauge arrangement distinctly different for x and y directions by virtue of being fixed on but both measuring on Wheatstone principles.
..2. for measurement of the strain in Z direction, a gauge is fixed on the inner wall of the drilled surface of the BOLT, AXLE, STUD, SHAFT or LINK as the case may be.
..3. 3. such specimen when used with BOLTS can be called INSTRUMENTED BOLT to measure strains in 3 directions, in X,Y and Z direction or be described differently
..4. such specimen when used with AXLES can be called INSTRUMENTED AXLE to measure strains in 3 directions, in X,Y and Z direction or be described differently
..5. such specimen when used with STUDS can be called INSTRUMENTED STUD to measure strains in 3 directions, in X,Y and Z direction or be described differently
..6. such specimen when used with SHAFTS can be called INSTRUMENTED SHAFT to measure strains in 3 directions, in X,Y and Z direction or be described differently
..7. such specimen when used with LINKS or mechanical member of any machine or device or contraption, however be constructed or described will be called INSTRUMENTED LINK to measure strains in 3 directions, in X,Y and Z direction Generically they will all be called XYZ INSTRUMENTED BASS MEMBERS.
..8. such capsule as described in claiml above will be fixed with standard resistive strain gauges These strain gauges could be of any make of any kind so long they fulfill the requirement of application.
..9. These strain gages as fixed on capsule can be 1 for each direction of X and Y or these could 2 for each direction connected in half bridge or 4 for each direction connected fn full bridge. The wires from these gauges are taken out of bolt/axle/stud/shaft or Link as the case may be for connection outside to any standard strain measuring instrument
..10. these holes made for inserting the capsule and for fixing the z-axis strain gages.are filled up with some resin to prevent damage to gauges or wires.