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STUD ANTI-ROTATION FEATURE

IP.com Disclosure Number: IPCOM000238551D
Publication Date: 2014-Sep-03
Document File: 7 page(s) / 601K

Publishing Venue

The IP.com Prior Art Database

Abstract

The invention proposes a technique to provide anti-rotation feature in a stud/bolt and nut in a gas turbine rotor. The technique includes locking feature which has three major parts provided for achieving anti-rotation. The parts include a slot in the stud thread end, a slotted washer and a D-Nut with projections at non-flange end. For example, the D feature is present in the nut for anti-rotation. Further, bolt anti-rotation is achieved by projections at non-flange end of D-nut and slotted washer. An embodiment of the invention includes an alternative locking mechanism assembly that includes slotted washer, nut and bolt. Slotted washer is made simpler for axial retention. Slotted washer is re-shaped into different types.

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STUD ANTI-ROTATION FEATURE

BACKGROUND

The present invention relates generally to a gas turbine rotor and more particularly to an inlet bleed heat system design for the gas turbine engine.

In general, in a bolted joint, a lock feature is required for anti-rotation of nut and bolt that helps in assembly and disassembly of the joint. When nut of one end is torqued, the nut at the other end is required to be still and not required to undergo rotation in order to achieve a preload acquired into the joint. Also the stud is required to be still during torquing. Usually, in a turbine rotor bolting, stud is held with an allen key (also known as hex-key) feature during torquing of nut so that the stud is not rotated.

Several conventional techniques are known in the art which includes different means for achieving anti rotation of stud/bolt and nut.

For example, in a conventional technique, anti-rotation of stud/bolt is achieved by friction between recessed parts.

In another conventional technique, anti-rotation of stud/bolt is achieved by hex feature in stud and a lock nut is engaged to clamping surface by serrations.

In one other conventional technique, anti-rotation is achieved by wavy surfaces of nut flange and washers mating.

In another conventional technique, anti-rotation of nut is achieved by wings of nut engaged against the next adjacent wheel.

Yet in one other conventional technique, anti-rotation of nut is achieved by clip kind of arrangement.

However, the above mentioned conventional techniques do not ensure positive stud locking. As a result, studs are damaged easily which increases expense of overall assembly.

Therefore there is a need in the art to provide a technique that ensures positive stud locking in a bolted joint of gas turbine rotor.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 depicts comparison of conventional bolt and nut configuration to that of the inventive configuration.

Figure 2 depicts parts and features included for providing anti-rotation of stud/bolt and nut.

Figure 3 depicts locking mechanism of nut and bolt in the rotor assembly.

Figure 4 depicts an alternate locking mechanism assembly including slotted washer, nut and bolt.

Figure 5 depicts axial retention of the slotted washer achieved by crimping nut projections by a lock pin passing through the nut projections and slotted washer.

Figure 6 depicts axial retention of the slotted washer achieved by crimping nut projections by a lock pin passing through the nut projection and locking to the slotted washer face

Figure 7 depicts torque resistance provided by locking feature at the cone/slotted washer.

DETAILED DESCRIPTION

The invention proposes a technique to provide anti-rotation feature in a stud/bolt and nut in a gas turbine rotor. The technique includes locking feature which has three major parts provided for achieving anti-rotation. The parts include a slot in the stud thread end, a slotted washer and a D-Nut with projections at non-flange end. For example, the D fe...