Patent Description:
Existing opto-mechanical support structures for optics and mechanical systems such as cameras and like imaging or information transmission systems are metallic based on shell designs with supportive ribs. Substitution of metal by fiber-reinforced polymer-matrix composites provides significant advantages such as lighter weight, corrosion resistance, durability, vibrational damping and more reliable supply chain availability without in advance ordering. Current composite structures usually mimic the existing metallic shell-based designs. However, current composite shell-based designs are limited by, among other things, relatively low stiffness and low strength properties in non-fiber orientations (transversal, shear, interlaminar) requiring their thickness increase with associated extra weight, complexity and cost of fabrication requiring considerable manual labor, additional risk of damage, especially in shell/ribs connections, and expensive quality/service control.

The conventional techniques have been considered satisfactory for their intended purpose. However, there is an ever-present need for improved systems and methods for improved composite components for optics support structures with potential for both design and manufacturing improvement/optimization. This disclosure provides a solution for this need. <CIT> relates to a method and a device for the manufacturing of a lightweight structure. <CIT> relates to composite structural panels. <CIT> relates to a method for manufacturing a hollow model.

A frame for an opto-mechanical support structure as defined in the independent claim <NUM> includes an interconnected lattice of frame composite rods defined about an interior space with interstices defined between the frame composite rods, wherein the interior space is six-sided and wherein at least one of the frame composite rods forms a continuous loop that extends across at least three sides of the interior space.

The lattice of frame composite rods can include a plurality of continuous loop frame composite rods interconnected with the lattice. The lattice of frame composite rods can include a plurality of dis-continuous loop frame composite rods interconnected with the lattice. The frame composite rods can be unidirectionally fiber-reinforced composite elements, e.g. composite tapes or combination of such tapes. Intersections of the frame composite rods can include interlaying of the composite element layers of the respective intersecting frame composite rods.

At least one of the frame composite rods can include a cross-sectional profile selected from the group consisting of: constant thickness, non-constant thickness where one surface of the cross-sectional profile is flat, non-constant thickness where opposed surfaces are both not flat, one rib extending from a base, multiple ribs extending from an external surface, a hollow shape, a hollow shape with an insert inside, multiple different materials in layers varied through thickness of the cross-sectional profile, and multiple different materials in layers varied through thickness and width of the cross-sectional profile.

One of the interstices can define an opto-mechanical aperture therethrough for admittance of optics image data through the lattice and frame. Wall panels can be mounted to an exterior aspect of the lattice for protection of the interior space. At least one of the wall panels can include an aperture therethrough, aligned with the optical aperture of the lattice. An opto-mechanical assembly can be mounted inside the lattice and frame with an objective lens aligned with an optics aperture through one of the interstices in the lattice.

Two or more frames as described above can be connected together as a three-dimensional gimbal.

A method of making an opto-mechanical frame as defined in the independent claim <NUM> includes forming a frame of interconnected lattice of frame composite rods using one or more fabrication processes by Automated Fiber Placement (AFP) technique around a mandrel. The method includes removing the mandrel from an interior space of the frame after forming the frame. In this method, the interior space is six-sided and at least one of the frame composite rods forms a continuous loop that extends across at least three sides of the interior space.

The method can include removing the mandrel by dissolving or washing the mandrel away after forming the frame. Forming the frame can include using at least one AFP arm to articulate fibers around the mandrel relative to a fixed frame of reference. Forming the frame can include rotating the mandrel relative to the fixed frame of reference. Forming the frame can include forming interlayered intersections of the frame composite rods in the lattice on a one-layer-at-a-time basis.

Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, a partial view of an embodiment of a frame in accordance with the disclosure is shown in <FIG> and is designated generally by reference character <NUM>. Other embodiments of systems in accordance with the disclosure, or aspects thereof, are provided in <FIG>, as will be described. The systems and methods described herein can be used to form composite frames for optics or opto-mechanical systems.

The frame <NUM> for an optical or other equipment support structure includes an interconnected lattice <NUM> of frame composite rods <NUM> defined about an interior space <NUM> with interstices <NUM> defined between the frame composite rods <NUM>. In <FIG>, not all of the interstices <NUM> are labeled for sake of clarity. Also shown in <FIG> is the mandrel <NUM> about which the frame composite rods <NUM> are formed. <FIG> shows the beginning of a frame structure, to which additional frame composite rods <NUM> can be added to form a complete frame <NUM>, for example as shown in <FIG>.

<FIG> shows another beginning stage for forming a frame <NUM>, with an Automated Fiber Placement (AFP) arm <NUM> forming a continuous, i.e., closed loop frame composite rod <NUM> about the mandrel <NUM>. The double arrows in <FIG> schematically indicate examples of movement orientations of the AFP arm <NUM>, e.g., relative to a stationary frame of reference, that can be used for forming the frame composite rods <NUM>. In other embodiments, using advanced AFP capabilities, the AFP arm <NUM> can move in all three space directions and similarly rotate in all three angular orientations. The circular arrows in <FIG> schematically indicate examples of the movement or rotation of the mandrel <NUM> itself, relative to the same stationary frame of reference, which can also be used for forming the frame composite rods <NUM>. Depending on the specifics of AFP implementation, the mandrel <NUM> can move and/or rotate in different directions and orientations. In this example, the frame composite rod <NUM> in <FIG> forms a continuous, i.e., closed, loop on itself and crosses over four faces of the <NUM>-sided mandrel (and corresponding interior space <NUM>, see <FIG>), e.g., the top, front, bottom, and back surfaces as oriented in <FIG>.

<FIG> shows another frame continuous, i.e., closed, loop forming a frame composite rod <NUM> that crosses all six surfaces of the mandrel (and corresponding interior space <NUM>, see <FIG>), and crosses each of the top and bottom surfaces twice, as oriented in <FIG> shows another continuous, i.e. closed, loop frame composite rod <NUM> that crosses the three adjacent sides (top, front, and right sides), and the bottom surface of the mandrel <NUM>, including crossing the bottom surface three times, as oriented in <FIG> shows another continuous or closed loop frame composite rod <NUM> that crosses the front, right, back, and left surfaces (the peripheral surfaces) of the mandrel <NUM>, as oriented in <FIG> shows a similar frame composite rod <NUM> to that shown in <FIG>, but crossing the left surface of the mandrel instead of the right, as oriented in <FIG>. Those skilled in the art will readily appreciate that any suitable continuous, i.e., closed, loop pattern can be used for frame composite rods <NUM> without departing from the scope of this disclosure, i.e., <FIG> show representative examples which can be similarly extended to other mandrel shapes and/or frame rod designs.

With reference now to an example of a composite frame shown in <FIG>, the lattice <NUM> of frame composite rods <NUM> includes a plurality of continuous loop frame composite rods <NUM>, such as those described above with reference to <FIG>, interconnected with the lattice <NUM>. The lattice <NUM> also includes a plurality of dis-continuous or open loop frame composite rods <NUM> interconnected with the lattice <NUM>. <FIG> show two-dimensional side views of two lattices <NUM>, respectively, one with a less dense lattice design, and the other with a more dense lattice design. Number and geometries of frame composite rods <NUM> can be used to control the lattice density and structural integrity according to specifics of a given application.

Additionally, the lattice <NUM> needs not to conform to a rectangular mandrel <NUM> or interior space <NUM> with rectangular cross-sections (labeled in <FIG>). <FIG> show frame composite rods <NUM> being formed on mandrels <NUM> shaped with a rectangular cross-section (<FIG>), with a rounded corner rectangular cross-section (<FIG>), with an oval, or more generally, convex cross-section (<FIG>), and with an arbitrary cross-section including both convex and concave segments (<FIG>). In addition to different two-dimensional geometries of cross-sectional designs, different three-dimensional geometries of mandrels can be similarly applied. Those skilled in the art will readily appreciate that any suitable lattice structure can be used for an opto-mechanical support structure without departing from the scope of this disclosure.

The frame composite rods <NUM>, <NUM> are unidirectionally reinforced by fibers polymer-matrix composite elements, which can all be formed by an AFP arm <NUM>, as shown in <FIG>. Carbon, glass and organic (e.g., Kevlar) fibers or any of their combinations can be used, among others, for the reinforcement. Thermoplastics or thermosets can be used as the polymer matrix. As shown in <FIG>, intersections <NUM> in the lattice <NUM> of the frame composite rods <NUM> include interlaying of the composite layers <NUM> or groups of layers <NUM> of the respective intersecting frame composite rods <NUM>, formed by laying the one layer (or group of layers) at a time in the intersection stack, every other layer (or group of layers) belonging to one of the intersecting respective frame composite rods <NUM>. The frame composite rods <NUM> can be formed layer by layer (or one group of layers by another group of layers), one layer (or one group of layers <NUM>) at a time to have any suitable cross-sectional profile.

The frame composite rods <NUM> in <FIG> have rectangular, constant thickness cross-sections, shown in <FIG>. Any other suitable cross-sectional configuration can be used for the frame composite rods <NUM>. <FIG> shows a frame composite rod <NUM> with a non-constant thickness where one surface of the cross-sectional profile is flat, i.e., the bottom layer <NUM> is flat, and the successive layers <NUM> upward from the bottom are successively narrower towards the top as oriented in <FIG> shows a non-constant thickness where opposed surfaces (i.e., the top and bottom layers <NUM> as oriented in <FIG>) are both non-flat. <FIG> shows a cross-sectional profile for a frame composite rod <NUM> with one rib <NUM> extending from a base, e.g., from the top or bottom layer, and <FIG> shows a cross-sectional profile with multiple ribs <NUM> extending from a base (with the base as the top layer in this example). <FIG> shows a cross-sectional frame composite rod profile with a hollow shape, and <FIG> shows one with a hollow shape having an insert <NUM> inside. The inserts <NUM> can be any suitable light-weight materials, for example, polymeric, foam, elastomeric, honeycomb, among others. The layers <NUM> can vary in material during the AFP process, giving a frame composite rod <NUM> with a cross-sectional profile having multiple different composite materials <NUM>/<NUM> in layers <NUM> varied through thickness of the cross-sectional profile, as shown in <FIG>. In <FIG>, the multiple different materials <NUM>/<NUM> in layers <NUM> are varied through thickness and width of the cross-sectional profile, as shown in <FIG>.

With reference now to <FIG>, one of the interstices <NUM> defines an optics or opto-mechanical aperture <NUM> therethrough for admittance of image data, e.g., optical or any portion of the electromagnetic spectrum for example, through the frame <NUM>. After forming the lattice <NUM>, the method includes removing the mandrel <NUM> (labeled in <FIG>) from an interior space <NUM> of the frame <NUM> after forming the frame <NUM>. The mandrel <NUM> can be removed by dissolving or washing the mandrel <NUM> away after forming the frame <NUM>. Wall panels <NUM>, e.g., of a composite monolithic or a sandwich design, can optionally be mounted to an exterior aspect of the frame <NUM> for protection of the interior space <NUM>. Such wall panels <NUM> can include one or more aperture <NUM> therethrough, e.g., aligned with the optics aperture <NUM> of the lattice <NUM>. The wall panels <NUM> can provide protection for optics/imaging components housed inside the lattice.

An example of usage of composite frames is illustrated in <FIG>. An optical and/or imaging assembly <NUM>, e.g., including a camera, lens, telescope, or the like, is mounted inside the lattice <NUM> with an objective lens <NUM> aligned with the optical aperture <NUM> through one of the interstices <NUM> in the lattice <NUM> (labeled in <FIG>). Two or more frames <NUM> constructed as disclosed herein can be connected together as a three-dimensional gimbal <NUM>, where two axes of rotation A and B are indicated in <FIG>.

Claim 1:
A frame (<NUM>) for an opto-mechanical support structure comprising:
an interconnected lattice (<NUM>) of fiber-reinforced frame composite rods (<NUM>) defined about an interior space (<NUM>) with interstices (<NUM>) defined between the frame composite rods; wherein the interior space is six-sided and wherein at least one of the frame composite rods forms a continuous loop that extends across at least three sides of the interior space.