The present invention relates generally to thermoplastic assemblies and more specifically, but not by way of limitation, to systems and methods for a thermoplastic tray table assembly utilizing compliant press-fit device members.
In the commercial aircraft industry, weight and safety are important issues. Even non-structural and non-critical elements such as tray tables on commercial aircraft should be designed with these in mind. For example, a weight savings on each tray can add up to a fairly significant weight savings for the aircraft as a whole, which in turn may reduce fuel expenditures and thereby provide an operational cost savings. Such reduction must not adversely affect strength.
Embodiments of the present invention relate to thermoplastic tray tables utilized in commercial airline industry, and more specifically, the passenger cabin area. Embodiments of the present invention are compatible with all types of tray tables, such as for example, single leaf and bi-fold multi-leaf tray tables. Embodiments of present invention are compatible with integral low density foam systems typically utilized in tray table assemblies.
Embodiments of the present invention are based on the elimination of the assembly processes and materials that induce or introduce weight—adhesive tapes (PSA's), epoxies and other binary and plural component systems all add significant weight during the process to integrate the exterior covers to the thermoplastic frame structure. Embodiments of the present invention address the need for a low cost, low weight alternative to the use of adhesives and other mechanical fasteners, and the processing time and costs required to employ same.
For a more complete understanding of embodiments of the present invention and for further objects and advantages thereof, reference may now be had to the following description taken in conjunction with the accompanying drawings in which:
Various embodiments of the present invention will now be described more fully with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
A thermoplastic homogenous tray table assembly includes top cover. A thermoplastic composite reinforced frame assembly with a plurality of compliant press-fit device receptacle apertures is homogenously chemically bonded to the top cover. The top cover frame assembly includes a plurality of integral precision recessed alignment features, mate-able to extended precision alignment features of the bottom cover frame assembly.
The tray table assembly further includes a bottom cover. A thermoplastic composite reinforced bottom frame assembly with a plurality of compliant press-fit receptacle apertures is homogenously chemically bonded to the bottom cover. The bottom cover frame assembly includes a plurality of integral precision extending alignment features, mate-able to recessed precision alignment features of the top cover frame assembly. The bottom cover frame assembly is installed to an assembly holding fixture integral to a manual or automated operating press system, with the plurality of compliant press-fit device receptacle apertures upward vertically oriented. A plurality of compliant press-fit assembly device members is provided and press-fit installed into the plurality of apertures of the bottom cover assembly. In a typical embodiment, a length portion of each compliant press-fit device member is vertically press-fit installed into each a receptacle aperture of the bottom cover frame assembly utilizing, for example, a compliant press-fit device member press-fitting tool pressing system. In a typical embodiment, vertical aligning and exposing a remaining portion length of the compliant press-fit device members. In one embodiment the compliant press-fit device has a length, the aperture in the bottom frame comprises a length, and the total length of the press-fit device is greater than the length of the aperture in the bottom frame.
The bottom cover frame assembly with the plurality of vertically exposed compliant press-fit device members is installed to an assembly holding fixture integral to a manual or automated operating press system, with the exposed compliant press-fit device members upward vertically oriented.
The top cover assembly with the plurality of compliant press-fit receptacle apertures, is proximally aligned to the exposed upward vertically oriented portion of the plurality of compliant press-fit device members of the bottom cover frame assembly. Additional precision alignment of the top cover frame assembly and the bottom cover frame assembly is provided by the integral precision alignment features of the top cover frame assembly and the bottom cover frame assembly.
The aligned top cover frame assembly is press-fit installed to the top cover frame assembly exposed upward vertically oriented plurality of compliant press-fit device members of the bottom cover via, for example, a suitable press-fit process, thereby producing a plurality of compliant assembly retention forces throughout the thermoplastic reinforced compliant press-fit tray table assembly to maintain retention of the top cover to the bottom cover.
The compliant press-fit device members can comprise of a specific dimensioned diametric (of, relating to, or consisting of a diameter, hereinafter referred to as “round” body with a length and diameter suitable to a particular application. In various embodiments, the body is further comprised of geometric features that create an angular slope of a specific length with the termination of the sloped length creating a diameter greater than the diameter of device member body. The slope terminates and creates a sharp corner barb type feature at the increased diameter.
In another embodiment, the compliant press-fit assembly device members can comprise flat or formed metallic materials with suitable mechanical properties to suit a particular application. The compliant press-fit assembly device members are comprised of a suitable thickness, width, and length, with integral spring features created through the thickness of the material. The spring features are formed, for example, by the creation of an aperture through a portion of the width and length of the material. The aperture creates remnant beams with a length and width, residing adjacent to the aperture with one beam opposing the other beam. The beam ends are distally connected to the material and comprise an arcing geometry. The beams further create a width greater than the width of the initial material width. The beams deflect inwardly and create a resistive force against the element providing a deflection force. A spring dynamic is created upon the deflection of the beam with an aperture. The dynamic provides retention forces.
The retention forces throughout the thermoplastic composite reinforced tray table assembly can be created by the use of the round device members, flat-formed metallic device members, or a combination of round and flat-formed metallic device members. As the compliant press-fit device members are press-fit installed into the apertures of the composite reinforced frame assembly, retention forces are created. Round device member retention forces are created by the compliancy of the frame assembly composite reinforced material forming about the barb feature during installation. In the case of the flat-formed device member, retention forces area created by the interference of the compliant beam springs into the apertures of the frame assembly.
The advantages and benefits gained by the use of thermoplastic carbon composites in all applicable industries can be realized upon the development of new processes that reduce processing costs but maintain the desired performance and quality levels. The cost of thermoplastic carbon composite high strength-to-weight ratio components and assemblies is tolerable to a limit due to the benefits gained by the use of such materials. A method to reduce processing and assembly times will equate to lower cost components and assemblies increasing the adoption and use of thermoplastic carbon composite components throughout many industries.
In order for thermoplastic carbon composites to be fully adopted for use in high volume applications, a method to reduce the processing and assembly times and associated costs must be developed and be more competitive than other current type systems. A high strength-to-weight tray table assembly with reduced weight and equal or greater mechanical performance will reduce cost and be a competitive alternative to current tray table assemblies.
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In another embodiment, the compliant press-fit assembly device members 110 can comprise flat or formed metallic materials with suitable mechanical properties to suit the application. The compliant press-fit assembly device members 110 comprise a suitable thickness, width and length, with integral spring features created through the thickness of the material. The spring features are formed by the creation of an aperture through a portion of the width and length of the material. The aperture creates remnant beams with a length and width, residing adjacent to the aperture with one beam opposing the other beam. The beam ends are distally connected to the material and comprise an arcing geometry. The beams further create a width greater than the width of the initial material width. The beams deflect inwardly and create a resistive force against the element providing the deflection force. A spring dynamic is created upon the deflection of the beam with an aperture. The dynamic provides retention forces.
The retention forces throughout the thermoplastic composite reinforced tray table assembly 100 can be created by the use of the round device members, flat-formed metallic device members, or a combination of round and flat-formed metallic device members.
As the compliant press-fit assembly device members 110 are press-fit installed into the apertures of the composite reinforced frame assembly, retention forces are created. Round device member retention forces are created by the compliancy of the frame assembly composite reinforced material forming about the barb feature during installation. In the case of the flat-formed compliant press-fit assembly device member 110, retention forces area created by the interference of the compliant beam springs into the apertures of the top cover frame assembly 106 and the bottom cover frame assembly 108.
Embodiments are based on the elimination of the assembly processes and materials that induce or introduce weight—adhesive tapes (PSA's), epoxies and other binary and plural component systems all add significant weight during the process to integrate the exterior covers to the thermoplastic frame structure. Certain embodiments allow the integration of multiple components into one homogenous assembly, providing consistent and repeatable positioning of same. Integration on a homogenous level also increases mechanical performance of the total assembly.
In the case of a Bi-Fold Tray Assembly, for example, there are four (4) covers that need to be affixed to the internal frame support assembly. The typical and most widely used method is the use of Pressure Sensitive Adhesive (PSA) Tapes or Binary/Plural Component epoxy. The current size of a typical Bi-Fold Tray, for example can exceed 17.5″ long×5″ wide. The amount of PSA required (area) can exceed 350 square inches for all four (4) covers. The weight of 350 square inches of PSA can exceed 85 grams or 3 ounces. Typically, large sheets of PSA are utilized as the PSA must capture all flat surfaces of the cover. This is due to the need to capture the integral foam inserts used and to minimize or eliminate the movement of the cover. The PSA is also, in some cases, utilized to enhance structural performance of the tray table assembly by providing an additional level of rigidity, although this is a minimal benefit.
A comparable weight of an adequate number of compliant press-fit assembly device members 110 for a Bi-Fold Tray Assembly is 5 grams. A potential weight saving in excess of 80 grams per tray table assembly can be realized. Additional weight savings can be achieved by the use of thermoplastic carbon reinforced frame assemblies. The cumulative weight reduction by eliminating heavy adhesives, fasteners and through the use of high strength-to-weight ratio materials can be significant.
During assembly, a top thermoplastic cover 102 is provided. The top cover 102 is formed via the methods discussed above, for example, thermo-vacuum forming, vacuum pressure forming, or injection molding. In various embodiments, the top cover 102 requires a secondary trimming process to remove excess materials remaining after the thermo-vacuum forming operation. The trimming operation provides a precision dimensioned thermo-vacuum formed thermoplastic top cover 102.
A bottom thermoplastic cover 104 is provided. The bottom cover 104 is formed via the methods discussed above, as an example. In various embodiments, the bottom cover 104 requires a secondary trimming process to remove excess materials remaining after the thermo-vacuum forming operation. The trimming operation provides a precision dimensioned thermo-vacuum formed thermoplastic bottom cover 104.
The top cover 102 and the bottom cover 104 further comprise an outer surface and an inner surface. The outer surface is typically provided with a suitable and visible texture. In a typical embodiment, the inner surface is typically formed with a smooth surface. The top cover 102 and the bottom cover 104 are installed into an injection mold tool. In a typical embodiment, the injection mold tool is geometrically configured to create an application-specific integral support structure. The top cover 102 and the bottom cover 104 are installed into the injection mold tool with the inner surface exposed. In a typical embodiment, the outer surface of the top cover 102 and the bottom cover 104 is retained within the injection mold tooling.
The injection mold tool provides an injection molding processes whereby a thermoplastic carbon or glass reinforced frame assembly is homogenously chemically bonded to the exposed inner surface of the top cover 102 and the bottom cover 104, creating a top cover frame assembly 106 and a bottom cover frame assembly 108. The top cover frame assembly 106 further comprises a plurality of integral precision recessed alignment features, which are mate-able to extended precision alignment features of the bottom cover frame assembly 108. The bottom cover frame assembly 108 further includes a plurality of integral precision extending alignment features, mate-able to recessed precision alignment features formed in the top cover frame assembly 106.
The injection mold tool additionally includes tooling elements that create apertures in the top cover frame assembly 106 and the bottom cover frame assembly 108. The apertures are geometrically configured to accept a compliant press-fit assembly device member 110. In a typical embodiment, the apertures can be a round form, or a square or rectangle form with suitable depth.
In a typical embodiment, a top and bottom cover frame assembly holding fixture is provided. The fixture is geometrically configured to match the outer surface of the top cover 102 and the bottom cover 104. The bottom cover 104 with the bottom cover frame assembly 108 joined thereto is installed to an assembly holding fixture integral to a manual or automated operating press system, with the plurality of compliant press-fit device receptacle apertures upward vertically oriented. A plurality of compliant press-fit assembly device members 110 is provided and press-fit installed into the plurality of apertures of the bottom cover frame assembly 108. In a typical embodiment, a length portion of each compliant press-fit assembly device member 110 is vertically press-fit installed into each receptacle aperture of the bottom cover frame assembly 108 utilizing, for example, a compliant press-fit device member press-fitting tool pressing system such that the compliant press-fit assembly device members 110 are vertically aligned and exposing a remaining portion length of the compliant press-fit assembly device members 110.
The bottom cover frame assembly 108 with the plurality of vertically exposed compliant press-fit assembly device members 110 is installed to an assembly holding fixture integral to a manual or automated operating press system, with the exposed compliant press-fit assembly device members 110 upward vertically oriented. In various embodiments, an additional assembly step can be provided to include installation of, for example tray table rods 118(a)-(b), bearings 114 and bearing clips 116 into at least one of the top cover frame assembly 106 and the bottom cover frame assembly 108 dependent upon the application.
The top cover frame assembly 106 with the plurality of compliant press-fit receptacle apertures, is proximally aligned to the exposed upward vertically oriented portion of the plurality of compliant press-fit assembly device members 110 of the bottom cover frame assembly 108. In various embodiments, additional precision alignment of the top cover frame assembly 106 and the bottom cover frame assembly 108 is provided by the integral precision alignment features of the top cover frame assembly 106 and the bottom cover frame assembly 108.
The aligned top cover 102 with the top cover frame assembly 106 joined thereto is press-fit installed to the bottom cover frame assembly 108 exposed upward vertically oriented plurality of compliant press-fit assembly device members 110 of the bottom cover frame assembly 108 via, for example, a suitable press-fit process. In a typical embodiment, the press-fit process produces a plurality of compliant assembly retention forces throughout the thermoplastic reinforced compliant press-fit tray table assembly 100 to maintain retention of top cover frame assembly 106 to the bottom cover frame assembly 108. Subsequent sealing operations to the mating edge joints of the top cover 102 and the bottom cover 104 can be provided as needed to meet application requirements.
Embodiments of the present invention include chemical and molecular compatible thermoplastic resins throughout the assembly creating an infinite number of homogeneous connective attachments that provide additional strength, dimensional stability, and rigidity. In addition, embodiments, of the present invention provide increased mechanical load-bearing capabilities via the integral formed thermoplastic carbon or glass reinforced composite injection molded into the thermoplastic formed cover. Embodiments reduce the current weight of a comparable tray table assembly by eliminating the assembly processes and materials that introduce weight such as, for example, adhesive tapes, epoxies, or other binary and plural component systems. Additionally, use of high strength-to-weight ratio thermoplastic materials and composites also results in embodiments described herein having a lower weight than comparable tray table assemblies. Embodiments described herein will reduce manufacturing costs through the use of homogeneous integration of the thermoplastic internal support structure and through the elimination of scrap rejections inherent with current production processes.
Although various embodiments of the method and system of the present invention have been illustrated in the accompanying Drawings and described in the foregoing Specification, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit and scope of the invention as set forth herein. It is intended that the Specification and examples be considered as illustrative only.
The present invention claims priority to Provisional Patent Application No. 62/480,941 filed Apr. 3, 2017 entitled “Method and System for Compliant Press-Fit Tray Table”, the entirety of which is hereby incorporated by reference.
Number | Date | Country | |
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62480941 | Apr 2017 | US |