Abstract:
An apparatus and method for latching a canopy to a vehicle, such as an aircraft, that avoids plastic creep and crazing due to concentrated loads is provided. The apparatus includes first attachment components that are at least partially embedded within an injection-molded canopy and second attachment components that are connected to the canopy rail for attaching to the one or more first attachment components and thereby attaching the canopy to the canopy rail.

Description:
PRIORITY 
   This invention is a Continuation Application of U.S. patent application Ser. No. 10/367,064, filed Feb. 13, 2003 now abandoned, which is 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 be 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, a frame provides structural stiffness and strong, secure, attachment points for hinges and latches. As is known, the viable frameless canopy system must include a method for latching. 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 or crazing due to concentrated loads yet securely holds the canopy in place. 
   SUMMARY OF THE INVENTION 
   The present invention provides an apparatus and method for latching a canopy to a vehicle, such as an aircraft, that avoids plastic creep or crazing due to concentrated loads. The apparatus includes first attachment components that are at least partially embedded within an injection-molded canopy and second attachment components that are connected to the canopy rail for attaching to the one or more first attachment components and thereby attaching the canopy to the canopy rail. 
   In another aspect of the invention, the first component includes a shaft with two ends and one or more knobs attached to the ends of the shaft. The knobs are molded into the canopy, and the shaft is exposed within a cavity formed by the canopy. The cavity is opened at a base of the canopy. 
   In still another aspect of the invention, the first component includes a hook at least partially embedded within the canopy. A portion of the hook protrudes from a base edge of the canopy. 

   
     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  illustrates an injection-molded frameless canopy attached to a vehicle in accordance with the present invention; 
       FIGS. 2 and 3  illustrate x-ray perspective views of a first embodiment for attaching the canopy to the vehicle; 
       FIG. 4  illustrates a perspective view of a canopy that includes an attachment mechanism in accordance with the second embodiment of the present invention; 
       FIG. 5  illustrates an exploded perspective view of the handrail attachment mechanism shown in  FIG. 4 ; 
       FIG. 6  illustrates a cutaway side view of the canopy of  FIG. 4  attached to a canopy rail; 
       FIG. 7  illustrates a cutaway perspective view of the system shown in  FIG. 6 ; 
       FIG. 8  illustrates a perspective view of an aircraft that includes the canopy shown in  FIG. 4 ; and 
       FIGS. 9–11  illustrate cutaway perspective views of a canopy that includes an attachment mechanism in accordance with a third embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention is an injection-molded canopy with canopy attachment devices that are inserted into the canopy during an injection molding process. As shown in  FIG. 1 , an exemplary canopy  20  attaches to a canopy rail  24  that surrounds a cockpit  26  of a vehicle  28 , such as an aircraft. 
     FIGS. 2 and 3  illustrate a first embodiment of an attachment device that is molded into an injection-molded canopy  30 . The attachment device is suitably a hook  32 . The hook  32  is substantially U-shaped. A first section  34  of the hook  32  expands in length away from a centerline of the hook  30 . A first section  34  is embedded within the canopy  30  during the injection molding process. A second section  42  of the hook  32  is exposed below the canopy  30 . The second section  42  includes a claw  44  and a U-shaped indent caused by the claw  44  and the first section  34 . When the injection-molded canopy  30  is fully formed around the first section  34 , the material of the canopy  30  holds the hook  32  in place by putting pressure on the expanded edges of the first section  34 . 
   A canopy rail  50  includes a canopy-receiving channel  52  that receives the canopy  30  and the mounted hook  32 . The canopy rail  50  is attached around a cockpit in a conventional manner. One of the walls of the channel  52  suitably includes an inflatable seal  58  that is attached to a pneumatic or hydraulic system (not shown) that is included within the vehicle. The inflatable seal  58  inflates when the canopy  30  is inserted into the channel  52  and locked in place in the canopy rail  50 . The inflatable seal  58  provides a moisture and air pressure seal between the vehicle cockpit and the environment outside of the cockpit. 
   In one embodiment, the canopy  30  is first inserted into the rail  50 . The canopy  30  is moved by a support structure (not shown), thereby making contact between the U-shaped cutout of the hook  32  and a locking mechanism (not shown) that is included as part of the canopy rail  50 . Co-pending patent application Ser. No. 10/367,062, hereby incorporated by reference, illustrates a mechanism for receiving the hook  32  without requiring fore and aft motion of the canopy  30  when the canopy  30  is inserted into the channel  52 . 
     FIG. 4  illustrates a perspective view of a second embodiment of an attachment device that is embedded within a canopy  100  during an injection molding process. In this embodiment, the attachment mechanisms are imbedded handle devices  102 . As shown in  FIG. 5 , the imbedded handle devices  102  include a U-shaped handle  104  and two pair of handle end holders  106 . Each pair of the handle end holders  106  includes a first part  106   a  and a second part  106   b . Each of the parts  106   a,b  includes a cavity that forms a cavity  110  that receives an end of the handle  104  when the parts  106   a,b  are combined. The parts  106   a,b  are attached to each other by a fastener  112 , such as without limitation a screw or a bolt, that is received through the first part  106   a  and is securely mounted into the second part  106   b . One or more securing pins  116  are received by respective pinholes in the first part  106   a  and are received into receiving cavities (not shown) within the second part  106   b . The pins  116  help reduce any rotational movement between the first and second parts  106   a,b . It can be appreciated that other fastener mechanisms, such as without limitation an adhesive, may be used for attaching the parts  106   a,b . Each end of the handle  104  includes a top section  120  that is wider from a centerline point than a bottom section  122 . The cavities  110  include chambers sized to receive each of the top and bottom sections  120  and  122 . Thus, when each parts  106   a,b  are coupled to each other with the ends of the handle  104  inserted within the cavities  110 , the handle  104  is held securely by the pairs of handle end holders  106 . 
   The end holders  106  are then inserted in a mold for the injection-molded canopy  100  such that when the molding of the canopy  100  is complete, the pairs of end holders  106  are surrounded by the molded canopy  100  and only the handles  104  protrude out of the base of the canopy  100 . In this embodiment the parts  106   a,b  are trapezoidal in shape with a first length at the side that includes the cavity  110  that is smaller than a second length of the side that is opposite the side that includes the cavity  110 . Therefore, because the parts  106   a,b  are wider at a point that will be further embedded into the canopy  100  after the molding process, the canopy material that surrounds the parts  106   a,b  holds the parts  106   a,b  securely in place. 
     FIGS. 6 and 7  illustrate a non-limiting example of mechanisms for securing the handle  104  to a canopy rail  130 . The canopy rail  130  includes a canopy receiving channel  132  that is formed by an interior wall  136 , a base  138 , and an exterior wall  134 . When the canopy  100  is received within the canopy channel  132 , the handle  104  passes through an opening  142  within the base  138  of the channel  132 . The opening  142  suitably includes a cap  144  that is spring-loaded to be forced open by the handle  104  when the handle  104  passes through the opening  142 . The cap  144  is suitably spring-hinged to the interior wall  136  underneath the base  138 . The cap  144  keeps water and other particulates from entering an interior of the canopy rail  130  when the canopy  100  is in an open position. The canopy rail  130  includes a handle-receiving hook  148  that rotates into position to grip the handle  104  once the handle  104  has fully penetrated the opening  142 . The hook  148  is suitably operated by conventional electromechanical devices and is activated when a switch (not shown) indicates that the canopy  100  is in proper position within the canopy channel  132 . The switch can be included within the cap  144 . The hook  148  keeps the handle  104  within the rail  130  thereby securing the canopy  100  to the canopy rail  130 . 
   In one embodiment, the exterior wall  134  of the canopy rail  130  includes an inflatable seal  150  along a wall of the channel  132 . The seal  150  inflates by a pneumatic or hydraulic system (not shown) that is included within the vehicle once the canopy  100  is fully seated within the channel  132 . The seal  150  provides a moisture and air pressure lock between the environment within the cockpit and outside of the cockpit. 
     FIG. 8  illustrates that the hooks  104  can be used to aide a pilot during ingress and egress from a cockpit  160  of an aircraft  170 . 
     FIGS. 9–11  illustrate perspective x-ray views of a third embodiment of the present invention. An attachment device  200  is embedded within an injection-molded canopy  202 . The attachment device  200  includes a shaft  204  with two knob ends  206  and  208 . During the injection-molding process of the canopy  202  the attachment device  200  is inserted near the base of the canopy  202 . The canopy  202  is molded so that the knob ends  206  and  208  are at least partially embedded within the canopy  202  and the shaft  204  has its longitudinal axis substantially perpendicular to a lengthwise axis of a cavity  210 . The shaft  204  is approximately centered within the cavity  210 . The cavity  210  is exposed at the base of the canopy  202 . 
   Referring to  FIGS. 9 and 10 , a canopy rail  220  includes a hook device  224 . When the canopy  202  is closed onto the canopy rail  220 , the hook device  224  is received by the cavity  210 . Then, either the canopy  202 , the hook device  224 , or the canopy rail  220  with the attached hook device  224  are slid so that the shaft  204  is received by the hook device  224 , thus locking the canopy  202  to the rail  220 . 
   It can be appreciated that various other types of attachment mechanisms can be imbedded within an injection-molded canopy during canopy creation. 
   While the preferred embodiment of the invention has been illustrated and noted above, many changes can be made without departing from the spirit and invention. Accordingly, the scope of the invention is not limited by the the preferred embodiment. Instead, the invention should be determined entirely