PREAMBLE: The invention resulted in development of a special purpose portable crane for removing and installing the engine units of the Helicopter during field service. This sophisticated & precised device replaced the earlier manual method, which was in-consistent, unsafe and time consuming.

FIELD OF INVENTION: This invention relates to design & development of a special purpose lifting crane, used to remove and install the engines of the Helicopter during field service. The device so developed is portable and capable of installing and aligning the engine units consistently, precisely and quickly at the desired location.

USE OF INVENTION: The special purpose device so developed, being portable is directly fixed on to the mounting brackets at three places provided on the Helicopter top body. The engine is attached to a three point lifting tool by lifting slings and together they are attached to the chain pulley system of the crane.

This concept is adopted for various applications having similar requirements of accuracy and equipment portability. This tool holds good for critical, high risk and precision positioning of the equipments on to any variant of the helicopters.

The special purpose device is more reliable and can be used in any condition.
PRIOR ART: The previous process describes manual removal andinstallation of the engine unit (approximately 200Kg) from/to the mounting brackets of the transmission engine deck area of the Helicopter fuselage while on field service. This operation is highly unsafe, risky, inaccurate and dependent on group of operator skill & consumes enormous time. The operation had to be carried out more carefully and due to in-consistency, the risks are high and these results in deviation. This being an assembly operation, rejections are costly and un-recoverable.

OBJECT OF INVENTION:

The modern Helicopter is equipped with a twin engine transmission system. The engine along with Integrated Dynamic System (IDS) is installed on the transmission deck. Further the engine is connected and aligned to the IDS. The engine unit is installed to the engine mounting brackets of the Transmission deck area. The mounting brackets arc located symmetrically opposite to each other about Helicopter center line fuselage.
Engine mounting brackets on Helicopter structure

Engine mounting system is a three point mounting system (As shown in Figure 1). The engine is supported at two points in the front and one point at the rear.

Front mount is designed to share the weight of the engine, torque loads and inertia loads as well as crash loads.

The side mount is located between front mount on inboard side of the engine and tail cone. This will take the side loads during helicopter maneuvers and crash.

The rear mount is designed

- To share the weight of the engine

- For giving provision for alignment of the engine vis-a-vis transmission by a knuckle joint through adjustable screw.

- To take care of axial thermal expansion of the engine; self-aligning bearings are provided in rear mount for this purpose.

In the earlier process, the engine .removal operation during field service used to be a very difficult and critical procedure as the weight of each engine is approximately 200 Kgs. During field service carrying heavy and robust cranes near to the Helicopter working area is merely an impossible task. More over the space around the deck area does not allow to work freely. The removal process involves removal of flexible shaft (a connector between engine and MGB), the drain systems, fuel systems, electrical connections, locking bolts nuts and washers etc. Then the engine is to be fixed to the engine lifting sling and then to be lifted. On field service the handling of the heavy engine unit safely becomes a risky, difficult and cumbersome job.This whole operation also requires substantial technician's patience & consumes enormous time for completion. In spite of these tight requirements and careful execution, the risks were high for any damage to the equipment assembly. The invention was necessitated in order to overcome the technical difficulties / short comings that existed in the prior manual method, in order to ensure quality & consistency.

The principal objective of the invention is to provide stable & accurate tooling in the form of a portable crane, which facilitates consistent and quick removal and installation of engine units for all versions of Helicopters. The tool also ensures the equipment safety and handling at par. In addition, the newly designed device is operator friendly, which saves substantial operation cycle time and increases safety of the equipment.

STATEMENT OF INVENTION:

The invention is a unique, high precision, special purpose tool for removing and installing of engine in a functionally critical zone of Helicopter transmission deck area. Another unique feature of the device is its suitability to load directly onto the Helicopter fuselage mounting brackets. Further the device ensures smooth holding, lifting, rotating and quick positioning of the equipments.

DETAILED DESCRIPTION OF THE INVENTION:

The invention relates to design & development of a special purpose portable lifting crane for removing and installing the engine from or to the Helicopter deck area. (As shown in Fig.-2)

The tool consists of a vertical rigid steel tubular column (Item no. 1) which is fixed to inclined tie tube (Item no. 4). A side vertical column (Item no. 2) is attached to the main tubular column through a triangular side support tubular structure assembly (Item no. 3). Each is again having fork end connectors in order to get attached to the mounting brackets fitted to the Helicopter fuselage.

The upper end of the vertical tube (Item no. 1) is fitted to a chain-pulley traveler beam (I-section) (Item no. 6) rigidly. The chain-pulley traveler beam houses the roller and pulley assembly (Item no. 7). This acts as a cantilever, so that it can reach out to either position of the engines on the Helicopter deck area.

The chain pulley system (Item no. 7) gives a flexibility to lift the engine equipment from its mounting brackets along with the attached lifting slings (Item no. 8) from Helicopter. In order to minimize the deflection, arising due to the cantilever effect, care has been taken to connect the chain- pulley traveler beam to the main vertical tubular column by an inclined tube (Item no. 5). '

The vertical column is fitted with bearing retainer brackets. This unit helps the upper lifting section of the tool to rotate about the vertical column axis by +/- 90 ° angle. This facility ensures safe positioning of the equipment either for removal or for installation.

Additional structural links are given for structural stability while working near Helicopter. As the requirement is during field service therefore the total tool is made to a portable size and detachable type for easy carrying and transportation.

The engine lifting sling tool (Item no. 8) is a dedicated tool for lifting of the engine. The tool is having 3 nos. of high tension wire ropes with eye end hook and D-shackles to get attached to the engine. This set up is again attached to the chain pulley arrangement (Item no. 7) made on the top of the chain-pulley traveler beam (Item no. 6). The chain pulley system makes the engine to get lifted as well as to bring it down as and when required. This can be handled by person standing at the ground. During the process it is very important to safe guard the engine equipment as well as the Helicopter equipments. Therefore a rotation facility is also provided in terms of bearing retainer brackets. Hence once lifted the entire engine equipment can also be rotated about the vertical column axis (As shown in Figure 3)

Because the need of this set up is during field service, this is designed to be light weight (130Kg.), easy to carry, assemble and dis-assemble on the helicopter or near to the helicopter.

SPECIFICATIONS of the Device:

1. Height :2950 mm

2. Weight of equipment : 130 Kg (Max.)

3. Crane capacity : 500 Kg (Max.)

4. Swiveling angle : +/- 90°

5. Hoisting distance : 1000 mm

6. Proof loading : 600 Kg

7. Welding : TIG welding

The special feature of the unit is, its light weight therefore easy to carry or transport and easy to assemble and dis-assemble on the Helicopter or near to the Helicopter for removing or installing the engines.

CLAIMS: We claim that

1. This is one of its kind portable special purpose crane, designed & developed for quickly removing / installing of engine equipment from Helicopter transmission engine deck area during field service.

2. The device is sturdy and stable thus minimizing the errors.

3. The device ensures safe, easy and effortless operation on helicopter transmission engine deck area.

4. This ensures accurate positioning of the engine assembly.

5. This is located to the hard mounting brackets of the Helicopter fuselage. Thus suitable to use at any place during field service.

6. This reduces the risk of damage to the equipment eventually.

7. The device is easy to set up & operate over the Helicopter transmission engine deck area thus eliminating the need of highly skilled technicians.

8. The schematic of the device has a high potential to be adopted for similar critical operations to be performed in-situ on Helicopters.