Abstract:
A system and method for attaching an injection molded canopy to a vehicle is provided. The system includes a canopy rail attached to the vehicle and an injection-molded canopy that is molded to be securely received by the canopy rail. The canopy is a polycarbonate or acrylic frameless canopy. The system also includes a seal, a canopy position sensor, a sealing component, and a canopy handle for controlling position of the canopy. The sealing component inflates the one or more seals with one of a liquid or gas when the canopy is sensed in the closed position. The system also includes a ground sensor. The sealing component deflates the seal if the canopy handle is in an open position and the aircraft is on the ground.

Description:
RELATED APPLICATIONS 
     This invention relations to copending U.S. patent application Ser No. 10/367,024, filed Feb. 13, 2003, U.S. patent application Ser. No. 10/367,064, filed Feb. 13, 2003, U.S. patent application Ser. No. 10/367,404, filed Feb. 13, 2003, U.S. patent application Ser. No. 10/367,403, filed Feb. 13, 2003, U.S. patent application Ser. No. 10/367,062, filed Feb. 13, 2003, all of which are hereby incorporated by reference. 
    
    
     GOVERNMENT LICENSE RIGHTS 
     This invention was made with Government support under U.S. Government contract F33615-97-2-3407 awarded by the U.S. Air Force. The Government has certain rights in this invention. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to vehicles with canopies and, more specifically, to closing mechanisms for injection-molded canopies. 
     BACKGROUND OF THE INVENTION 
     Modern aircraft canopies contain many parts. A transparent portion of the canopy may he replaced several times during the life of an aircraft due to scratches and general deterioration. Replacement of the transparent portion entails frame disassembly and reassembly. This is time-consuming, labor intensive, and costly. 
     Attempts have been made to produce frameless aircraft canopies in order to simplify replacement of the transparent portion, among other reasons. However, viable frameless canopy system must include a method for latching. As is known, the frame provides structural stiffness and strong, secure, attachment points for hinges and latches. Prior latching methods include a male hook or pin located on the aircraft structure or canopy frame and a female receiver on the canopy frame structure or aircraft structure respectively. Such discrete latching methods produce concentrated loads, which cause bearing stress in the transparency in the region of the latch. 
     Stress causes problems for transparencies. Glassy polymers craze at low stress levels. The effect of crazing on crack growth and localized failure is not well understood. Polymer transparencies yield at low stress levels and creep occurs after a fraction of service life. Cyclic, long-term loading, such as cockpit pressurization, induces creep and/or craze and reduces service life. Elevated temperatures, such as those experienced by high-speed aircraft, further increase the rate of creep and amplify the effect of crazing. 
     Therefore, there exists an unmet need to produce a latching system for an injection-molded canopy which avoids plastic creep and crazing due to concentrated loads yet securely holds the canopy in place. 
     SUMMARY OF THE INVENTION 
     The present invention provides a system and method for attaching an injection-molded canopy to a vehicle that avoids plastic creep and crazing due to concentrated loads while securely holding the canopy in place. The system includes a canopy rail attached to the vehicle and an injection-molded canopy that is molded to be securely received by the canopy rail. The canopy is at least one of a polycarbonate or acrylic frameless canopy. The system also includes a seal, a canopy position sensor for sensing position of the canopy, a sealing component, and a canopy handle for controlling position of the canopy. The sealing component inflates the seal with one of a liquid or gas when the canopy is sensed in the closed position 
     In one aspect of the invention, the vehicle is an aircraft and the system includes a ground sensor for sensing when the aircraft is on the ground. The sealing component deflates the seal if the canopy handle is in an open canopy position and the aircraft is sensed to be on the ground. 
     In another aspect of the invention, the canopy includes a channel for receiving the one or more seals. 
     In another aspect of the invention, the canopy is injection molded with protrusions, and the canopy rail includes flanges that mate with the protrusions when the canopy is placed in a closed and locked position within the canopy rail. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings. 
     FIG. 1 is a perspective view of a portion of an aircraft and cockpit with a frameless canopy in an open position; 
     FIG. 2 is a perspective view of a portion of a frameless canopy and rail formed in accordance with a first embodiment of the present invention; 
     FIGS. 3A and 3B are perspective views of a portion of a frameless canopy and rail formed in accordance with a second embodiment of the present invention; 
     FIG. 4 illustrates a cross-sectional view of a frameless canopy and rail formed in accordance with a third embodiment of the present invention; and 
     FIG. 5 illustrates a block diagram of components of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention includes attachment mechanisms for an injection molded, frameless canopy. As shown in FIG. 1, a frameless canopy  26 , such as without limitation a polycarbonate or acrylic injection-molded canopy, is attached to a hinge mechanism  28  that opens and closes the frameless canopy  26  about a cockpit  32  of a vehicle  20 , such as an aircraft. The frameless canopy  26  is injection-molded with a base edge shaped to mate with a canopy rail  30  that surrounds the cockpit  32  and is fixed to the vehicle  20 . Advantageously, no heavy machining of the canopy  26  is required, because the canopy  26  is molded to be received securely by the canopy rail  30 . Thus, the integrity of the frameless canopy  26  is maintained thereby allowing for a long service life. 
     FIG. 2 illustrates a partial perspective view of an injection-molded frameless canopy  50  that is molded to be received by a canopy rail  52 . The canopy  50  includes a base section  56  that includes an inboard side  60 , an outboard side  62 , and a base edge  70 . The inboard and outboard sides  60  and  62  include a row of securing pins  66 . The row of securing pins  66  are spaced apart at a predefined distance from each other and are located a predefined height from the base edge  70 . Each pin  66  extends through and out from the respective side  60  or  62  and is rounded on a side closest to the base edge  70  and flat on a side furthest from the base edge  70 , thereby forming a shape of a “D” laid on its side. The pins  66  are metallic pins installed in the injection mold and molded in place integrally within the canopy or are subsequently installed after molding and retained with an “E” clip. The shape of the pin  66  allows for ease in movement with respect to the rail  52 , but could be of various other shapes. 
     The canopy rail  52  includes a first main channel  76  that is formed by an inboard section  80  of the rail  52  and an outboard section  82  of the rail  52 . The inboard section  80  includes a channel  84  and the outboard section  82  includes a channel  86 . The channels  84  and  86  are on opposite sides of the main channel  76  at a predefined height above a base of the main channel  76  and are parallel with a longitudinal axis of the canopy rail  52 . Above the channels  84  and  86  are securing teeth  90  that are separated by predefined teeth gaps  92 . 
     The canopy  50  mates with the canopy rail  52  as follows. The canopy  50  is lowered such that the pins  66  pass through the gaps  92  between the securing teeth  90  and become positioned within the channels  84  and  86 . The bulk of the section  56  is received by the main channel  76  with the sides  60  and  62  below the pins  66  lodging adjacent to interior walls of the sections  80  and  82  that are below the channels  84  and  86 . The canopy  50  is then slid forward or aft with respect to the canopy rail  52  in order to position each knob  66  between a base wall of the respective channels  84  or  86  and a securing tooth  90 . The top of each pin  66  is now in contact with the bottom of the teeth  90 . Contact between the securing teeth  90  and the pins  66  keeps the canopy  50  locked to the canopy rail  52 . 
     In an alternate embodiment with respect to the embodiment shown in FIG. 2, a channel is molded into the bottom edge  70  of the canopy  50  (not shown). The channel receives an inflatable seal (not shown) that is located at the base of the main channel  76  of the canopy rail  52 . The seal and channel produce a moisture and air pressure lock between the cockpit and the environment outside of the cockpit. 
     In another alternate embodiment with respect to the embodiment shown in FIG. 2, one of the walls or base that forms the channel  76  includes an inflatable seal (not shown). When the seal inflates, the seal makes contact with the canopy  50  and produces a moisture and air pressure lock. 
     FIGS. 3A and 3B illustrate a second embodiment of attaching an injection-molded frameless canopy  100  to a canopy rail  102 . The frameless canopy is injection molded to include protrusions  110  that protrude from an outboard side  112  of the canopy  100 . The protrusions  110  protrude from a base edge  120  of the canopy  100  and slope back into the canopy  100 . The protrusions  110  are spaced at predefined intervals on the outboard side  112 . 
     The canopy rail  102  includes a channel  138  formed by a base  140 , an outboard wall  142 , and an inboard wall  144 . The outboard wall  142  is sloped in order to match the slope of the protrusions  110 . The outboard wall  142  includes equally spaced securing teeth  150 . To close the canopy  100 , the canopy  100  is positioned so that the protrusions  110  pass through gaps between the teeth  150  as the canopy  100  is inserted into the channel  138 . Then, the canopy  100  is slid so that each protrusion  110  is secured under a securing tooth  150 . The contact between the protrusions  110  and the respective tooth  150  keeps the canopy  100  mated with the rail  102 . Wall sections  154  are attached to the base  140  of the channel  138  and the outboard wall  142  and are approximately perpendicular to the wall  142  and the base  140 . Each wall section  154  is attached near one end of a tooth  150 . The wall sections  154  stop motion of the canopy  100  past the teeth  150  by making contact with a side of the protrusions  110 . 
     The canopy  100  includes an inboard side  160  that is molded according to the shape of the inboard wall  144  of the rail  102 . In one embodiment, the wall sections  154  stop forward motion of the canopy  100  and the inboard wall  144  stops inboard motion of the canopy  100 . 
     A channel  166  is molded into the base of the canopy  100 . The channel  166  receives a seal (not shown) that is located on the base  140  of the canopy rail  102 . When the canopy  100  is in place and secured to the canopy rail  102 , (i.e., the protrusions  110  are secured in place behind respective teeth  150 ) the seal, such as without limitation a pneumatic or hydraulic bladder, mates within the channel  166  of the canopy  100  thereby providing a moisture and air pressure lock between the cockpit and the environment outside of the cockpit. Pneumatic or hydraulic system components within canopy rail  102  connect to pneumatic or hydraulic components within the vehicle when the rail  102  is closed and mated with the vehicle around the sill of the cockpit (not shown). When the structure  102  is secured to the aircraft around the canopy sill (not shown), the seal is inflated within the channel  166 , thereby providing a pressure seal between the aircraft cockpit and the environment outside of the cockpit. 
     In an alternate embodiment with respect to the embodiment shown in FIGS. 3A and 3B, the channel  166  is not present and the base  140  includes an inflatable seal (not shown). When the seal inflates, the seal makes contact with the canopy  100  and produces a moisture and air pressure lock. 
     FIG. 4 illustrates a third embodiment of the present invention. A canopy  200  includes a first channel  210  molded into an inboard side  202  of the canopy  200  near the base of the canopy  200  and a second channel  212  molded within an outboard side  204  of the canopy  200  approximately opposite the first channel  210 . A canopy rail  214  includes a channel  216  that is shaped to receive the canopy  200 , so that the channels  210  and  212  are located within the channel  216 . On approximately opposite sides of the channel  216  are first and second channels  218  and  220 . The first and second channels  218  and  220  have inflatable seals  222  and  224  attached therein. The channels  218  and  220  are located on the sides of the main channel  216  at a height such that when the canopy  200  is properly inserted within the main channel  216 , the channels  210  and  212  match the channels  218  and  220 . 
     Before the canopy  200  is inserted into the canopy rail  214 , the seals  222  and  224  are in an uninflated mode so that they do not significantly protrude into the main channel  216 . Once the canopy  200  is properly seated within the main channel  216 , the seals  222  and  224  are inflated by either air or fluid from a hydraulic or air pressure system within the vehicle. The inflated seals  222  and  224  securely mate within the channels  210  and  212 , thereby, providing a mechanism of locking the canopy  200  to the rail  214  and for providing a moisture and air pressure lock between the cockpit and the environment outside the cockpit. 
     FIG. 5 is a block diagram of the embodiments that include air or hydraulic seals that separate cockpit pressure from environment pressure or secure the canopy to the vehicle. A canopy seal system  250  includes a canopy position controller  260 , one or more pumps  262 , one or more seals  264 , and one or more canopy position sensors  266 . The system  250  includes a ground sensor  270  when the vehicle is an aircraft. When the canopy is closing as instructed by the canopy position controller  260  being in a close-canopy position, the canopy position sensor  266  sends a canopy closed signal to the one or more pumps  262  after the canopy has reached the closed position. In response to the canopy closed signal, the pumps  262  inflate the one or more seals  264  with a gas or a fluid. 
     When the canopy is closed and locked with inflated seals  264  and the canopy controller  260  is placed in an open-canopy position, the pumps  262  or a pressure relief valve (not shown) deflates the seals  264 . After the seals  264  have sufficiently deflated, the canopy is opened. If the vehicle is an aircraft, the pumps  262  or a pressure relief valve (not shown) deflates the seals  264  when the canopy controller  260  is placed in an open-canopy position and the ground sensor  270  senses that the aircraft is on the ground. 
     While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.