Patent Description:
Typically, piloted airplanes have certain control surfaces including horizontal stabilizers or ailerons, and vertical stabilizers or rudders to control movement of the airplane during flight. These control surfaces are also used to trim, or stabilize, the airplane during flight. Also, like automobiles, airplanes also include braking systems to control movement of the plane while on the ground. Generally, these conventional braking and control surfaces, including the rudder, are operated by various mechanical links and connecting rods or hydraulic or electromechanical actuators, which are operated by the pilot and allow the pilot to control the airplane's flight path. For various reasons, it is often desirable to link the rudder and braking controls of the pilot and co-pilot. The aforementioned conventional rudder and braking system are typically operated by pedals located under the cockpit instrument panel. In conventional systems, these mechanical linkages typically contain bell cranks and connecting rods, and extend under the floor of the flight deck.

<CIT> describes dual pedal controls for wheel brakes.

<CIT> describes a system for backdriving the flight deck controllers of a fly-by-wire aircraft that is under autopilot control to provide a pilot with tactile and visual feedback of autopilot activity. The system, distributed between the aircraft primary flight computers and the autopilot flight computer, uses actuators mechanically coupled to each flight deck controller to position the flight deck controller to mimic manual operation of the flight control surfaces.

<CIT> describes a light airplane pedal device which comprises a main rotating shaft, a main rotating shaft sleeve, an auxiliary rotating shaft, an auxiliary rotating shaft sleeve, a left main pedal, a left auxiliary pedal, a right main pedal and a right auxiliary pedal. The main rotating shaft is arranged in the main rotating shaft sleeve in a rotating fit mode, the auxiliary rotating shaft is arranged in the auxiliary rotating shaft sleeve in a rotating fit mode, and the main rotating shaft sleeve and the auxiliary rotating shaft sleeve are hinged to a rudder pull rod through insertion lugs respectively.

<CIT> describes an aircraft control that comprises a mobile pedal and comprises a cylinder coupled to the pedal such that a displacement of the pedal according to at least a first direction reduces the volume of a first chamber of the cylinder.

<CIT> describes dual driving controls for a road vehicle with an elongate transmission element providing coordinated movement of both sets of pedals.

Embodiments of the invention detailed below represent an improvement to the state of the art with respect to airplane control systems. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.

In one aspect, the invention as defined in appended claim <NUM> provides a cable-linked brake pedal assembly for an airplane. The assembly includes a first cable assembly with a first end attached to a pilot-side brake pedal and a second end attached to a first bell crank assembly, and a second cable assembly with a first end attached to a copilot-side brake pedal and a second end attached to a second bell crank assembly. A first connecting rod with a first rod end is attached to the first bell crank assembly and a second rod end is attached to the second bell crank assembly. The connection between the first and second cable assemblies, first and second bell crank assemblies, and first connecting rod is configured such that depressing the pilot-side brake pedal moves the first cable assembly, first connecting rod, and second cable assembly in such a way as to cause a corresponding depression of the copilot-side brake pedal.

In a particular embodiment, the connection between the first and second cable assemblies, first and second bell crank assemblies, and (first) connecting rod is configured such that depressing the copilot-side brake pedal moves the second cable assembly, first connecting rod, and first cable assembly in such a way as to cause a corresponding depression of the pilot-side brake pedal.

In a further embodiment, the cable-linked brake pedal assembly also includes a third cable assembly with a first end attached to a second pilot-side brake pedal and a second end attached to a third bell crank assembly, a fourth cable assembly with a first end attached to a second copilot-side brake pedal and a second end attached to a fourth bell crank assembly, and a second connecting rod with a first rod end attached to the third bell crank assembly and a second rod end attached to the fourth bell crank assembly. The connection between the third and fourth cable assemblies, third and fourth bell crank assemblies, and second connecting rod being configured such that depressing the second pilot-side brake pedal moves the third cable assembly, second connecting rod, and fourth cable assembly in such a way as to cause a corresponding depression of the second copilot-side brake pedal.

In a particular embodiment, the connection between the third and fourth cable assemblies, third and fourth bell crank assemblies, and second connecting rod is configured such that depressing the second copilot-side brake pedal moves the fourth cable assembly, second connecting rod, and third cable assembly in such a way as to cause a corresponding depression of the second pilot-side brake pedal.

In certain embodiments, the first bell crank assembly includes an inner bell crank and an outer bell crank, each configured as a wheel member, the inner bell crank attached to an end of the first cable assembly. The outer bell crank may be attached to the first rod end of the first connecting rod. In a particular embodiment, the inner and outer bell cranks are coupled by a jam alleviation mechanism such that the inner and outer bell cranks move in unison. In particular embodiments, the jam alleviation mechanism comprises a spring-loaded detent mechanism configured to uncouple the inner and outer bell cranks so that the inner bell crank can move independently of the outer bell crank. In more particular embodiments, the spring-loaded detent mechanism is configured to displace a pin that couples the inner and outer bell cranks when a predetermined amount of torque is applied to the first bell crank assembly.

Embodiments of the first cable assembly include an inner core, which is drawn in tension when the pilot-side brake pedal is depressed. The first cable assembly may also include an outer conduit, which provides a flexible service loop. In some embodiments, the first cable assembly further includes an end fitting to facilitate attachment to the first bell crank assembly. Additionally, the first cable assembly may include an end ferrule configured for attachment to a bell crank of the first bell crank assembly.

On the contrary, the scope of the invention is defined by the appended claims.

<FIG> is a perspective view of a cable linked brake pedal assembly <NUM> for an airplane, constructed in accordance with an embodiment of the invention. In the embodiment shown, a pilot-side brake pedal assembly <NUM> is connected to a co-pilot-side brake pedal assembly <NUM> via a cable system, which will be described in more detail below. As can be seen in <FIG>, a first pilot-side pedal <NUM> is coupled to a first co-pilot-side pedal <NUM> via a first pilot-side cable pair <NUM>, a first connecting rod <NUM>, and a first co-pilot-side cable pair <NUM>. Similarly, a second pilot-side pedal <NUM> is coupled to a second co-pilot-side pedal <NUM> via a second pilot-side cable pair <NUM>, a second connecting rod <NUM>, and a second co-pilot-side cable pair <NUM>.

<FIG> is a plan view of the cable member <NUM> in accordance with an embodiment of the invention. The cable member <NUM> includes an outer conduit <NUM> and an end fitting <NUM> for attachment and tensioning. The inner core <NUM> of the cable assembly is drawn in tension when the brake pedal <NUM>, <NUM>, <NUM>, <NUM> is actuated and pulls on the cable end ferrule <NUM>. The tension in the cable inner core <NUM> transfers motion to a bell crank assembly (shown <NUM>, <NUM> in <FIG>) through wheel members attached to the brake pedal <NUM>, <NUM>, <NUM>, <NUM>, similar to the wheel on a pulley system. The assembly <NUM> is designed such that the cable tension transmits an identical motion back to the opposite station pedal through the cable end ferrule <NUM> of the cable member <NUM> for the opposite station pedal.

Referring again to <FIG>, the pilot-side bell crank assembly <NUM> includes a first pilot-side bell crank <NUM> and a second pilot-side bell crank <NUM>. The co-pilot-side bell crank assembly <NUM> includes a first co-pilot-side bell crank <NUM> and a second co-pilot-side bell crank <NUM>. <FIG> is a perspective view showing a close up view of two of the pedals <NUM>, <NUM>, shown in <FIG>, as coupled to their respective cable members <NUM>. Each pedal <NUM>, <NUM> has an integral wheel member <NUM>, similar to the wheel member for a pulley system. In a certain embodiment, activating or depressing the brake pedal <NUM>, <NUM>, <NUM>, <NUM> rotates the wheel member <NUM> and operates the wheel brakes of the airplane.

In particular embodiments of the invention, the wheel member <NUM> may have a groove to seat the inner core <NUM> of the cable member <NUM>. The cable member <NUM> is assembled onto the wheel member <NUM>, which includes an element configured to hold on to the cable end ferrule <NUM>.

In particular embodiments such as that shown in <FIG>, the wheel member <NUM> is assembled to two cable members <NUM> such that the wheel member <NUM> is configured to hold on to two cable end ferrules <NUM>. In this arrangement, rotation of the wheel member <NUM> in a first direction places tension on one of the two cable members <NUM>, and rotation of the wheel member <NUM> in a second direction opposite the first direction places tension on the other of the two cable members <NUM>. However, it is envisioned that embodiments of the invention include those in which the wheel member <NUM> has only one cable member <NUM>, which reacts to tensile and compressive loads, and one attached end ferrule <NUM>.

When the pilot, for example, presses down on one of the pedals <NUM> (shown in <FIG>), the wheel member <NUM> is rotated in the aforementioned first direction. Through its attachment to the end ferrule <NUM>, the rotation of the wheel member <NUM> tensions one of the cable members <NUM> displacing the inner core <NUM> of the cable through the arcuate distance of the wheel member rotation. In this example, the pilot-side pedal <NUM>, <NUM> is depressed. The opposite end of the displaced cable member <NUM> is attached to a wheel member <NUM> (shown in <FIG>) on one of the pilot-side bell cranks <NUM>, <NUM>. The wheel member <NUM> is similar to the wheel member <NUM> on the pedals <NUM>, <NUM>, <NUM>, <NUM>, and are attached to the end ferrule <NUM> of one or two cable members <NUM>. As such, the aforementioned displacement of the wheel member <NUM> is transferred, via the cable member <NUM>, to the wheel member <NUM>.

The wheel member <NUM> is also attached to one end of the first or second connecting rod <NUM>, <NUM>. The other end of the connecting rod <NUM>, <NUM> is attached to a wheel member <NUM> (shown in <FIG>) on one of the co-pilot-side bell cranks <NUM>, <NUM>. As such, the aforementioned rotation of the pilot-side wheel member <NUM> causes the connecting rod <NUM>, <NUM>, to which it is attached, to move linearly in a horizontal direction. Movement of this connecting rod <NUM>, <NUM> causes the co-pilot side wheel member <NUM> to rotate in correspondence with the rotation of wheel member <NUM>. Rotation of the co-pilot-side wheel member <NUM> displaces its respective cable member <NUM>, which rotates the wheel member <NUM> on the co-pilot-side pedal <NUM>, <NUM>, which, in turn, causes the co-pilot-side pedal <NUM>, <NUM> to depress in concert with the pilot-side pedal <NUM>, <NUM>.

Conversely, if the copilot depresses a copilot-side pedal <NUM>, <NUM>, the aforementioned system of cable members <NUM>, bell crank assemblies <NUM>, <NUM>, and connecting rods <NUM>, <NUM> is configured to transmit motion from the copilot-side pedal <NUM>, <NUM> through its respective connecting rod <NUM>, <NUM> to the bell crank <NUM>, <NUM>, <NUM>, <NUM> in the opposite bell crank assembly <NUM>, <NUM>. The driven bell crank assembly <NUM>, <NUM> applies tension similarly to the opposing cable assembly <NUM> in the opposite station. In so doing, the cable tension transmits an identical motion back to the pedal <NUM>, <NUM> of the opposite station.

<FIG> is a perspective view of one of the bell crank assembly <NUM> represented by any of the four bell crank assemblies <NUM>, <NUM>, <NUM>, <NUM> in the cable linked brake pedal assembly <NUM> of <FIG>, and constructed in accordance with an embodiment of the invention. In the embodiment shown, the bell crank assembly <NUM> includes two separate members: an inner bell crank <NUM> and an outer bell crank <NUM> which are coupled together by a jam alleviation mechanism <NUM> that has a specific amount of torque preload that can be transferred. In a particular embodiment, one or both of the inner and outer bell cranks <NUM>, <NUM> are configured as wheel members similar to the wheel in a pulley system.

<FIG> is a perspective view of the bell crank assembly <NUM> of <FIG> showing attached cable members <NUM>. In a particular embodiment of <FIG>, the inner bell crank <NUM> is similar to the wheel member <NUM>, <NUM> described above. Thus, embodiments of the inner bell crank <NUM> may be grooved to help seat the inner core <NUM> and end ferrule <NUM> of the cable member <NUM>. In the embodiment shown, the inner bell crank <NUM> is attached to two cable members <NUM>, though it is envisioned that, in alternate embodiments, the inner bell crank <NUM> may be attached to only one cable member <NUM>. In the embodiments shown, the end fittings <NUM> of the two cable members <NUM> are secured within openings in a bell crank assembly housing <NUM>. Outside of the bell crank assembly housing <NUM>, the outer conduit <NUM>, which provides a flexible service loop. The flexible service loop allows for adjustments to the pedal position and transfer of displacement without additional linkages. The flexibility also allows the assembly <NUM> to avoid interferences within the tight confines of the cockpit. Within the bell crank assembly housing <NUM>, the inner core <NUM> and end ferrule <NUM> are attached to the inner bell crank <NUM>.

In <FIG>, the outer bell crank <NUM> includes a clevis <NUM> with an opening to facilitate the attachment of the outer bell crank <NUM> to the connecting rod <NUM>, <NUM>. The connecting rod <NUM>, <NUM> may be attached to the clevis <NUM> of the outer bell crank <NUM> using a mechanical fastener, or the end of the connecting rod <NUM>, <NUM> may be inserted through the opening in the clevis <NUM>. The inner bell crank <NUM> and outer bell crank <NUM> are coupled by the jam alleviation mechanism <NUM> such that the bell cranks <NUM>, <NUM> move in unison. In the particular embodiment of <FIG>, the inner bell crank <NUM> and outer bell crank <NUM> each rotate on a respective set of bearings <NUM>. In certain embodiments, such as shown in <FIG>, the inner bell crank <NUM> is attached to two cable members <NUM>, and seats two inner cores <NUM> and two end ferrules <NUM>. However, in alternate embodiments, the inner bell crank <NUM> may be attached to one cable member <NUM>.

As referenced above, one feature that may be incorporated in the jam alleviation mechanism <NUM> is the ability to limit the torque load that may be transmitted through the bell crank assembly <NUM>. One advantage of such a feature could be reduced cable sizing and improved flexibility and force contributions for the cable assembly <NUM>. <FIG> and <FIG> show the jam alleviation mechanism <NUM> with a spring-loaded detent mechanism <NUM> to limit the torque load. In the event that a jam prevents the proper rotation of either the inner or outer bell cranks <NUM>, <NUM>, when a sufficient amount of torque is applied to one of the brake pedals <NUM>, <NUM>, <NUM>, <NUM>, the spring-loaded detent mechanism <NUM> displaces a pin <NUM> which breaks the connection between the inner and outer bell cranks <NUM>, <NUM> allowing the inner bell crank <NUM> to rotate independently of the outer bell crank <NUM> and vice-versa. In this way, the jamming of one brake pedal does not affect the brake pedal of the opposite station.

In alternate embodiments of the invention, the jam alleviation mechanism <NUM> may be provided by a clutch, or a shear pin, or a torsional spring preload mechanism. For example, a particular embodiment of the jam alleviation mechanism <NUM> includes a clutch with a rotary friction disc assembly that is preloaded by a spring load to establish a prescribed amount of torque transmission capability. In the event of a system jam when a pedal load above the load that exceeds the prescribed friction torque is applied, the jam alleviation mechanism <NUM> will allow movement beyond the position at which the control is jammed. The exercised control may not return after load application depending on the nature of the jam.

In another embodiment, the jam alleviation mechanism <NUM> includes a shear pin in which a rotary coupling that contains the shear pin or necked down section of torsion shaft that is designed to fracture at prescribed amount of torque transmission capability. In the event of a system jam when a pedal load above the load that exceeds the prescribed shear torque is applied, the jam alleviation mechanism <NUM> will break free and allow free movement of the control station (pilot or copilot) that is not jammed.

In yet another embodiment, the jam alleviation mechanism <NUM> includes a torsion spring pre-load that utilizes a rotary sprung return-to-center device that is preloaded by a spring load to establish a prescribed amount of torque transmission capability. In the event of a system jam when a pedal load above the load that exceeds the prescribed friction torque is applied, the jam alleviation mechanism <NUM> will allow movement beyond the position at which the control is jammed and the controls will return to alignment at the jammed position upon removal of the load.

In another embodiment, the jam alleviation mechanism <NUM> could also be incorporated in the connecting rod <NUM>, <NUM> in a linear fashion. In a further embodiment of the invention, the connecting rod <NUM>, <NUM> could be removed altogether and all of the cable connections could be made through a single bell crank. In yet a further embodiment, both bell cranks assemblies <NUM>, <NUM> and both connecting rods <NUM>, <NUM> could be removed, such that a simple connection from the pilot pedal <NUM>, <NUM> to the copilot pedal <NUM>, <NUM> is made through a direct cable linkage between the two pedals. In such an embodiment, the jam alleviation mechanism <NUM> could be incorporated in a linkage segment within the direct cable linkage.

Claim 1:
A cable-linked brake pedal assembly (<NUM>) for an airplane, the cable-linked brake pedal assembly comprising:
a first cable assembly (<NUM>) with a first end attached to a pilot-side brake pedal (<NUM>, <NUM>) and a second end attached to a first bell crank assembly (<NUM>);
a second cable assembly (<NUM>) with a first end attached to a copilot-side brake pedal (<NUM>, <NUM>) and a second end attached to a second bell crank assembly (<NUM>);
a first connecting rod (<NUM>, <NUM>) with a first rod end attached to the first bell crank assembly (<NUM>) and a second rod end attached to the second bell crank assembly (<NUM>);
the connection between the first and second cable assemblies, first and second bell crank assemblies, and first connecting rod being configured such that depressing the pilot-side brake pedal (<NUM>, <NUM>) moves the first cable assembly (<NUM>), first connecting rod, and second cable assembly (<NUM>) in such a way as to cause a corresponding depression of the copilot-side brake pedal (<NUM>, <NUM>).