WO2014206380A1

WO2014206380A1 - Mounting set for mounting and dismounting of aircraft engines

Info

Publication number: WO2014206380A1
Application number: PCT/CZ2013/000079
Authority: WO
Inventors: Jan KODET; Pavel SUMERA; Markus Daniel ZEBISCH; Frantisek Sobotka
Original assignee: Hennlich S.R.O.
Priority date: 2013-06-27
Filing date: 2013-06-27
Publication date: 2014-12-31

Abstract

A mounting set for mounting and dismounting of aircraft engines comprising at least three chain hoists (1) and a set of brackets (2) for suspension of the chain hoists (1) on the supporting structure of the airplane. Each chain hoist (1) is equipped with an electric servo motor (3), position sensor (5) and force sensor (6). All the sensors (5, 6) and electric servo motors (3) are connected to a control unit (4) with a control panel (7). The control unit (4) is equipped with a block for control of the electric servo motors (3) based on the data of the position sensors (5) and force sensors (6).

Description

Mounting set for mounting and dismounting of aircraft engines Technical Field

The invention relates to a mounting set for mounting and dismounting of aircraft engines comprising at least three chain hosts and a set of brackets for suspension of the chain hoists on the supporting structure of the aircraft.

Background Art

Jet engines of aircraft are attached to the supporting structure of the wing or fuselage of the aircraft with the use of screws. After releasing of these screws the engine can be dismounted and transported to a specialized workshop for the execution of a repair or regular maintenance.

To lower the engines during the dismounting or to lift the engines during the mounting various types of hoists are used.

The simplest known mounting set, called Bootstrap, contains 3 to 4 chain hoists with hand drive, a set of brackets for suspension of the hoists on the aircraft wing pylon and a set of certified dynamometers to measure the chain force. The entire set is kept in a transport container. An advantage of such a set is a low price, low weight, quick deployment and easy operation of the chain hoists.

A disadvantage of a mounting set with chain hoists with manual drive is that during the entire lowering/lifting operation each hoist must be operated by one person and another person must visually check parts of the aircraft and the engine for possible collision situations. Lowering/lifting of the engine represents manually demanding work as the control force on the chain hoist lever is approx. 15 - 20 kg.

Another disadvantage is problematic synchronization of simultaneous lowering/lifting of the chain hoists. Especially in the case of large engines when 4 chain hoists are used this leads to overloading of one of the four hoists as a plane is defined by 3 points.

During the mounting of an engine the engine must be lifted until the engine flanges not only bear on the supporting structure of the airplane, but also until between the engine flanges and the supporting structure of the airplane the prescribed pre- stressing (typically approx. 500 kg) is produced. It is only this way that you can implement the screw connections in compliance with the airplane manufacturer's instructions for engine mounting/dismounting. The operators of the chain hoists must visually read the actual pre-stressing values on the dynamometers, which means that a negative human factor influence cannot be avoided. Moreover, the risk of occurrence of a reading error is multiplied by the number of used hoists and thus the required number of operators. A too low pre-stressing value results in unacceptable stressing of the entire screws by the engine weight - the screws then substitute the function of the hoist or local deformation of the connecting flange may occur while a too high pre-stressing value may even cause engine deformation. The visually checked pre-stressing values cannot be archived for possible future inspection.

Strenuous physical work is eliminated with a known mounting set with 3 to 4 chain hoists, each hoist being fitted with pneumatic drive. The remaining content of this mounting set is the same as that of a mounting set with chain hoists with hand drive. This means that it also contains a set of brackets for suspension of the hoists on the aircraft wing pylon and a set of certified dynamometers to measure the chain force. The entire set is kept in a transport container. Again, an advantage of such a set is a low price, low weight, relatively quick deployment and easy operation of the chain hoists.

The mounting set with chain hoists with pneumatic drive eliminates strenuous physical work; however, this mounting set requires that during the entire engine lifting/lowering operation each hoist be operated by a person that switches on/off the pneumatic drive of the assigned chain hoist and visually reads the current value of the dynamometer of his chain hoist. In addition, another person is required again that visually monitors possible collision conditions between airplane parts and the engine. Thus, in this case problematic synchronization of simultaneous lowering/lifting of the chain hoists and the resulting risk of overloading of one of the four hoists and the risk of setting a wrong pre-tensioning value between the engine flanges and the supporting structure of the airplane due to erroneous reading of data of one of the dynamometer represents a disadvantage, too. With this embodiment the visually checked pre-tensioning values cannot be archived for possible future inspection either.

Large service facilities use pillar jacks with hydro motors or servo motors. Unlike the above mentioned chain hoists that are suspended on the aircraft structure with the use of brackets pillar jacks are positioned on the floor under the airplane. Therefore, the floor must be relatively flat. All the pillar jacks are connected to a control unit with a control panels that can be used to control the hydro motors or servo motors of the pillar jacks. An advantage is that you can easily synchronize the movement of the pillar jacks, you can set the required pre-tensioning, which is checked automatically and the corresponding data can be archived. A disadvantage is a high price of such equipment and a high weight, which makes transport difficult.

The goal of the invention is to design such equipment that would be as affordable and mobile as known sets with chain hoists and that would feature the same operation comfort as expensive and heavy mounting sets with pillar jacks at the same time.

Disclosure of Invention

The above mentioned problem is solved by a mounting set for mounting and dismounting of aircraft engines comprising at least three chain hoists and a set of brackets for suspension of the chain hoists on the supporting structure of the airplane while each chain hoist is equipped with an electric servo motor, position sensor and force sensor. All the sensors and electric servo motors are connected to a control unit with a control panel. The control unit is equipped with a block for controlling the electric servo motors on the basis of data of the position sensors and force sensors.

An advantage of the mounting set according to the invention is that it combines the advantages of all the types of known mounting sets for mounting and dismounting of aircraft engines without exhibiting their disadvantages. This means that it is affordable cost-effective and it can be easily transported even by air like the known mounting sets with manually controlled chain hoists and at the same time it features the same safety and comfort level as the expensive and heavy mounting sets with pillar jacks.

A mounting set according to the invention enables both synchronization of movement of all the chain hoists and the possibility of independent movements of individual chain hoists, so the mounted engine can be inclined along the longitudinal as well as transversal axis.

By using the data of the force sensors during the mounting of the engine on the pylon the control unit only allows exertion of such pre-tensioning force that is specified in the maintenance manual for the particular aircraft engine. Thus, the influence of human factor by reading the dynamometer data is eliminated.

In mounting sets according to the invention with four chain hoists the control unit eliminates the risk of overloading of one of the four hoists, which may occur due to a well-known fact that a plane is defined by three points.

Another advantage is that the mounting set according to the invention can be operated by only one person working with the control panel and an assistant that monitors those parts of the engine and pylon that are found in the mounting space for possible mechanical damage. Also, the mounting set according to the invention is easy and quick to deploy. The mounting set according to the invention does not have any requirements for the quality of the workshop floor surface as in the case of expensive pillar jacks, which must be placed on a flat surface under the airplane.

In a preferred embodiment the control unit is equipped with a memory for saving the measured data, so the fact that the pre-tensioning force values prescribed by the maintenance manual were met during the mounting can be evidenced afterwards.

To make the handling of the control panel easy the control panel can be designed as a mobile one.

Brief Description of Drawings

A sample embodiment of the mounting set for mounting and dismounting of aircraft engines according to the invention is shown in fig. 1 in an axonometric representation and in fig. 2 in a schematic representation.

Description of preferred embodiments

Figs. 1 and 2 show a sample embodiment of the mounting set for mounting and dismounting of the CFM56-7 jet aircraft engine of the Boeing 737-800 transport airplane.

The mounting set comprises three chain hoists 1 made by the company Budg^'it, where the two front chain hoists 1 are placed symmetrically along the longitudinal axis of the engine 10 and feature the carrying capacity of 2t and the rear chain hoist 1 is located eccentrically at one side of the engine 10 only and its carrying capacity 1t.

Each chain hoist 1 is provided with an electric servo motor 3 made by B&R with an angular countershaft gearbox, motor brake, position sensor 5 and force sensor 6. In the described sample embodiment the position sensor 5 comprises of an absolute induction transducer made by the Company Heidenhain and the force sensor 6 consists of a certified tensometer with the capacity of 5t.

The mounting set further comprises two brackets 2 of light metals for suspension of the chain hoists 1 on the pylon 8 under the airplane wing 9. On the pylon 8 of the wing 9 there is a flange 14 of the pylon that corresponds to the flange 13 of the engine 10 (see fig. 2).

Each chain hoist 1 is suspended on the bracket 2 with one end and on a dismountable holder on the engine 10 with the opposite end.

The described mounting set for mounting and dismounting of the CFM56-7 jet aircraft engine comprises three chain hoists 1. For heavier engines 10 such mounting sets are used that comprise four chain hoists 1 arranged symmetrically along both sides of the engine 10.

All the electric servo motors 3, position sensors 5 and force sensors 6 are connected with cables to the control unit 4, which is equipped with a block for control of the electric servo motors 3 based on the data of the position sensors 5 and force sensors 6.

The control unit 4 is further equipped with a control panel 7, which is designed as a separated panel that is attached to the control unit 4 with a cable for higher mobility. The control panel 7 is provided with a touch screen for easy operation and it has a lock button, an emergency stop button, functional switches of lifting/lowering, rotation along the transversal or longitudinal axis, indicators lamps of the power supply and operation of the equipment, a control joystick, USB connector and ETHERNET connector.

The control unit 4 is also equipped with a memory for saving measured data. Before dismounting of the engine 10 and before installation of the mounting set the covers are first removed and dismountable holders for the chain hoists 1 are installed on the engine 10.

Then, the front and rear bracket 2 are attached to the pylon 8 under the airplane wing 9, the chain hoists 1 are suspended on the brackets 2 and their free ends are attached to the holders on the engine 10. The electric servo motors 3 of the chain hoists 1 , position sensors 5 and force sensors 6 are connected to the control unit using the respective cables.

The touch screen of the control panel 7 is used to select the airplane type, position of the engine 10 that is just being handled, engine 10 type, operation type (mounting/dismounting), parameters of pre-tensioning between the flange 14 of the pylon 8 and the flange 13 of the engine 10, settings of the swivel points both along the longitudinal and transversal axis. During operation the touch screen 7 displays operation and error messages, positions of individual chain hoists 1 and the forces acting on their suspensions.

After releasing of the screws between the flange 14 of the pylon and the flange 13 of the motor 10 the released engine can be lowered on a cradle 11 on the shipping stand 12.

The control unit 4 is equipped with a block for control of the electric servo motors 3 depending on the data of the position sensors 5 and force sensors 6. The control unit 4 continuously evaluates the lift distance of the chain hoists 1 and the forces measured by individual force sensors 6. This enables both synchronization of the movement of all the chain hoists 1 and the possibility of independent movements of individual chain hoists 1. Thus, rotation along the longitudinal as well as transversal axis can be achieved.

Re-assembly of the engine 10 onto the pylon 8 is done in an analogous way. As soon as the flange 13 of the motor 10 touches the flange 14 of the pylon 8, based on data of the force sensors 6 the control unit 4 will only allow exertion of such a pre-tensioning values that is specified in the maintenance manual for the particular airplane engine 10.

The control unit 4 is equipped with a memory for saving measured data, so the fact that the pre-tensioning force values prescribed by the maintenance manual were observed during the mounting of the engine 10 can be evidenced afterwards.

Claims

1. A mounting set for mounting and dismounting of aircraft engines comprising at least three chain hoists (1) and a set of brackets (2) for suspension of the chain hoists (1) on the supporting structure of the airplane, characterized in that each chain hoist (1) is equipped with an electric servo motor (3), position sensor (5) and force sensor (6) while all the sensors (5, 6) and electric servo motors (3) are connected to a control unit (4) with a control panel (7) and the control unit (4) is equipped with a block for control of the electric servo motors (3) based on the data of the position sensors (5) and force sensors (6).

2. The mounting set in accordance with claim 1 , characterized in that the control unit (4) is equipped with a memory for saving of measured data.

3. The mounting set in accordance with any of claims 1 or 2, characterized in that the control panel (7) is designed as a mobile one.