1. TITLE OF INVENTION

Design of jig to achieve lineability of multiple locking holes, interchangeability of Canopy Side Frame.

2. FIELD OF INVENTION

The present invention related to mechanical engineering in general and in particular to jigs used for aircraft systems.

3. BACKGROUND OF INVENTION

Canopy configuration is side hinged on right hand (RH) side of the Aircraft with locking mechanism on left hand side (LH) of the Aircraft. The Canopy is provided with counter poise system to assist pilot to open and close the Canopy with little effort.

The Canopy assembly consists of various components i.e. Canopy Side Frame assemblies (Left hand side and Right hand Side), Rear Arch, Front Arch and Canopy Bubble. The Canopy locking mechanism consists of Canopy Assembly, Longeron and locking brackets.

Canopy Side Frame assemblies (LH & RH) plays a crucial role to achieve lineability and ICY on installation of Canopy Assembly on Aircraft. The Canopy Side Frame Assemblies (LH & RH) are usually contoured in shape and length of about 1.4 meters with multiple reamed holes at hinge points and these holes are to be maintained with lineability along hinge axis with ICY dimensions with reference to the Longeron mold plane and Aircraft Centre Line (C/L).

Canopy side frames are fabricated using 5 axis CNC machine and checked for lineability and ICY of locating holes at hinge locations.

In many aircraft industries, achieving lineability and ICY of Canopy Side Frames along hinge axis is difficult due to contoured profile of the part and warpage/slenderness.

Document CN113977499A with title “Canopy air tightness test, relates to a canopy airtightness test fixture and provides methods of sealing on canopy during installation. Present invention describes the Jig for achieving lineability and interchangeability of Canopy Side Frame.

Document JP201507491OA with title “Mounting Structure and Mounting Method of Canopy for Vertical Shaft", provides the solution to divide a canopy for a vertical shaft into two or more members, carry it to a mounting field, and enable it to be safely mounted to the vertical
shaft without a worker working in the inside of the vertical shaft. This invention not provides the novel approach, however present invention provides a novel approach of a jig to arrest the degrees freedom during drilling and reaming.

4. BRIEF SUMMARY OF THE INVENTION

In order to overcome the above issue, a dedicated jig is designed and fabricated for Canopy Side Frame with removable locators to facilitate proper clamping/holding by arresting the degrees of freedom while drilling and reaming of Canopy locating holes at Hinge points along Hinge axis before and after bush pressing to ensure required locking of Canopy Assembly on Longeron.

5. BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows Schematic Diagram of Canopy Assembly with Longeron. It indicates Side Frame Assembly (RH) (4) with hinge points, i.e., Forward hinge point (6), Middle hinge point (7) and Rear hinge point (8), Canopy bubble (2), Longeron (5), Locating Bracket (11), Bushes (9) and Bolts (10).

Fig.2 shows the Jig for Canopy Side Frame consisting of removable locators i.e. Front Locator (13), middle locator (14), rear locator (15) with base plate (12) and side L-angle (16) for arresting the Canopy Side Frame.

6. DETAILED DESCRIPTION OF THE INVENTION

A Jig for drilling and reaming on Canopy Side Frame is designed and fabricated. This invention overcomes the present issue as per the details below:

(A) Base plate (12) is made up of Aluminium material for light weight with flatness accuracy 50 microns of 1.5 meter length, 157 mm width and thickness of 20 mm to>avoid warpage on Base plate (12).

(B) Three numbers of removable locators i.e., Front Locator (13), Middle Locator (14) and Rear Locator (15) made up of Steel and fastened on Base plate (12) using Bolts (17)

and Dowell Pins (18) with accuracy of 30 micron. The removable locators (13, 14 and 15) are used to drill and ream the locating holes at hinge points along hinge axis.
(C) A Side L-Angle (16) is fixed on Base plate (12) using Bolts and Dowell pins to ensure the degrees of freedom of Canopy Side Frame during drilling and reaming of locking holes.

(D) By using above jig setup, Canopy Side Frame is mounted on Base plate and locked at removable locators and ensured arresting the degrees of freedom using side L-Angle for drilling and reaming of locking holes.

(E) The existing under size hole Canopy Side Frame is opened out to final diameter in stages using special drill gun, drill bits, reamer and guide bushes to ensure lineability and hinge axis. Canopy side Frame removed from jig after drilling and reaming of holes.

(F) Bushes are pressed on Side Canopy Frame after drilling and reaming of holes and become Canopy side Frame Assembly.

(G) Canopy side Frame Assembly is positioned and locked on jig. The existing hole on Bushes are drilled and reamed to final size in stages using special drill gun, drill bits, reamer and guide bushes as per the drawing.

By using above novel setup lineability and interchangeability on Canopy Side Frame Assembly is achieved at hinge points.