1 Title of the Invention
External Lock for Aircraft Control Surface.
2 Field of the Invention
The present invention relates to mechanical engineering in general and
particularly relates to aircraft ground support equipment and external lock
for Aircraft control surfaces.
3 Background of the Invention
Aircraft flight control surfaces are used to control motion of the aircraft.
These control surfaces direct airflow to affect pitch, roll and yaw movement
of the aircraft and manually operated through cockpit controls. The roll and
pitch movements are primarily controlled by joy stick whereas the yaw
movement is controlled by rudder‘pedal.
Control surfaces are key to an aircraft operation while moving through air.
Same time these surfaces are subjected to wind forces while aircraft is
stationary. Wind gusts can cause more. damage to the control Surfaces of
an aircraft while Aircraft towing or in parked condition.
3.1 Prior Art
Aircraft internal locks have provided in prior art, which restricts movement
of Control surfaces. These may be by using a pin on joystick or a cord to
tie joystick with rudder pedal.
US3330504 — This disclosure uses T-shaped member in cockpit for‘
locking the cockpit pedal and wheel controls of an aircraft and it prevents
movement of the' pedals and wheel thereby locking the external control
.surfaces of the aircraft. This lock is large in size, expensive, cumbersome
and adding unwanted weight to aircraft. It may also cause stress on
internal control linkage. Thus, an external Control Surface lock is
advantageous than internal one.

4 Brief Summary of the Invention

This invention is intended to provide a device known as Exiemal lock for
‘Control Surfaces. This is used {0 keep off the surfaces from moving when
the aircraft on ground or aircraft while towing. The Lock prevents damage
of control surfaces and linkages due to gust of wind. A typical external
control surface locks uses leverage between a fixed surface and moving
surface to restrict the movement.
Present disclosure provides a control surface lock mechanism for securing
aircraft control surfaces Aileron and Rudderv comprising of a set of top and
‘
bottom plates connected with a rectangular metal bar and locked with a
cam. However, same mechanism can be extended to any movable control
_
surface used on an aircraft and this is a universal type of external control
surfaces locking device.
5 Detail Description of the Drawings
Figure 1: a top side view of external control surface Lock ‘assembly which
shows top plate 1, cam lock 3 with bolt 5 and split pin 6.
Figure 2: a bottom side view of external control surface lock assembly
which shows bottom plate -12, Capture pin 9 is connected to connecting
bar'4 with split pin 10 and 11 and metal ring 7 with warning strip 8.
Figure 3: shows an isometric view of a gust lock being placed across the
gap between Flap and Aileron of a wing in unlocked position.
Figure 4: an isometric view of a gust lock being placed across the gap
between Flap and Aileron of a wing in locked position.

6 Detail Description of the lnvention
- Present disclosure provides a control surface lock mechanism for
securing aircraft control surfaces comprising of a set of top and bottom
plates connected with a rectangular metal bar and locked with a cam.
For the purpose of this disclosure, an aircraft aileron will be used as an

example of aircraft control surface to
’
be locked however same
mechanism can be extended to any movable control surface used on an
aircraft. Figure 1 through Figure 4 represent aircraft external surface
lock (Figure 1 and Figure 2) and cam locking mechanism with aircraft
5 control surface (Figure 3 and Figure 4);
Basic element of an external cohtrol surface include item (1) to (13) as
described further. Bottom side of Top plate (1) glued with rubber sheet
(2) with adhesive; 80 that there is no scratch or damage from metal to
metal contact while employing external control surface lock. Similarly
10 there is bottom plate (12) top portion of Which is glued with rubber sheet
(13) with adhesive; Both top plate (1) and bottom plate (12) have
rectangular opening in middle to accommodate rectangular connecting
bar (4); Width and thickness of opening is slightly greater than to width
and thickness of connecting. bar (4); Collectively top plate (1) and
15 bottom plate (12) are made of fairly rigid material to handle anticipated
wear/tear and load. Further connecting bar (4) has three holes one at
I
top side and two at bottom side. Top hole will be connected to Cam lock
(3) with bolt (5) and split pin (6); Connecting hole in Cam lock (3) is not
exactly at the centre as seen from the Figure 1; It is done to provide
cam action for positive locking of top plate (1); Middle hole which is not
in the middle of connecting bar (4) is located at below 01; bottom plate
(12).
Capture pin (9) is connected to connecting bar (4) with split pin (10) and
(11); Capture pin (9) locks bottom plate (12) with aircraft control surface
25 when cam lock (3) is i'n locked position; Bottom hole of connecting bar
(4) is used to secure metal ring (7) which in turn used to secure warning
stripv(8) of signal red colour. "Remove Before Flight" is written in black
colour.

Figure 3 shows taking assembly inside the gap between moving
1 surface Aileron and fixed surface Flap of wing. That is Why thickness of connecting bar (4) is less than the gap. Figure 3 shows external control
surface .lock in unlocked position. By moving the cam as shown in
5 Figure 4 cam may be locked. In this position capture pin (9) will exert
force on bottom plate (12) and Cam lock (3) will exert force on top plate
(1). Connecting bar (4) may be moved'forward or backward in thé gap
so as to get proper clamping force. Excessive force may damage the
item. This process of locking may be applied in any control surface of
10 any aircraft, provided there is a moving surface and fixed surface. Sizes
may vary according to requirement.

We Claim,
1. An apparatus for externally locking aircraft control surfaces comprising:
A top plate (1) and a bottom plate (12) glued with rubber sheet (2.13);
a rectangular opening in middle to accommodate a conhecting bar (4);
wherein said connecting bar (4) has three holes one at top and two at
bottom;
top hole is connected to Cam lock (3) with bolt (5) and split pin (6) to
provide cam action for positive locking of said top plate (1) with aircraft
structure;
Capture pin (9) is connected to said connecting bar (4) middle hole
with split pin (10,11) to lock said bottom plate (12) with aircraft
structure; and
warning strip (8) is connected to the bottom hole of said connecting bar'
(4) with metal ring (7).