Patent Description:
<CIT> discloses a universal joint comprising a central cross member, whose arms are each connected to an arm of one of two yokes between which torque is to be transmitted, by frictionless resilient couplings inserted between the yokes and the arms. Each coupling may comprise a pair of C-shaped plates held in grooves by brazing.

In an aspect, the present disclosure provides a flexural pivot manufacturing system, comprising: a fixture having a bottom support and a top support coupled to the bottom support; a plurality of flexural pivot support member workpieces coupled to the fixture; and standoff spacers located adjacent sides of the plurality of flexural pivot support member workpieces to position the bottom support and the top support relative to one another and thereby position the plurality of flexural pivot support member workpieces relative to one another, the top support and the bottom support having a plate or block configuration and the standoff spacers being disposed between the top and bottom supports; the plurality of flexural pivot support member workpieces including a first flexural pivot support member workpiece supported by and coupled to the bottom support, a second flexural pivot support member workpiece supported by and coupled to the top support, and flexure openings and wells in fluid communication with the flexure openings extending into ends of the flexural pivot support member workpieces to form flexure support members, the wells comprising cylindrical openings, wherein the top and bottom supports facilitate: disposing at least one flexure in the flexure openings, wherein the at least one flexure has first and second flexible blades arranged in a cross configuration and extending into the wells of the flexure support members, the cylindrical openings of the wells oriented to extend along ends of the flexible blades, and disposing coupling material in the wells to couple the at least one flexure to the flexure support members to provide for rotational movement of the flexure support members relative to one another.

In another aspect, the present disclosure provides a method of making a flexural pivot, comprising: coupling a plurality of flexural pivot support member workpieces to a fixture, wherein a first flexural pivot support member workpiece is coupled to a bottom support of the fixture, and a second flexural pivot support member workpiece is coupled to a top support of the fixture; coupling the top and bottom support to one another; forming flexure openings and wells in fluid communication with the flexure openings extending into ends of the flexural pivot support member workpieces to form a plurality of flexure support members; disposing at least one flexure in the flexure openings of the plurality of flexure support members, wherein the at least one flexure has first and second flexible blades arranged in a cross configuration and extending into the wells of the flexure support members, the wells comprising cylindrical openings oriented to extend along the ends of the flexible blades; disposing a coupling material in the wells; and heating the coupling material sufficiently to cause the coupling material to flow into the flexure openings to couple the at least one flexure to the flexure support members and thereby rotatably couple the plurality of flexure support members to one another.

An initial overview of the inventive concepts is provided below and then specific examples are described in further detail later. This initial summary is intended to aid readers in understanding the examples more quickly, but is not intended to identify key features or essential features of the examples, nor is it intended to limit the scope of the claimed subject matter.

A variety of flexural pivots are commercially available for variety of applications. Common problems with typical commercial off-the-shelf (COTS) flexural pivots that have brazed joints are repeatable performance and reliability, particularly where high performance and durability are required for the application. This may be due to the difficulty in manufacturing flexural pivots in a commercially viable manner. Additionally, applications that require relatively large angular ranges of motion may cause stresses that exceed the strength of COTS flexural pivots, often resulting in brazed joint failures. Thus, it is desirable to develop a flexural pivot design that provides high performance, large angular travel, and reliability while being relatively simple and cost-effective to produce.

Accordingly, a flexural pivot is disclosed with brazed joints that can provide high performance, large range of motion, and reliability and that is readily able to be manufactured. The flexural pivot can include a plurality of flexure support members, each flexure support member having a plurality of flexure openings and a plurality of wells each in fluid communication with a respective flexure opening. The flexural pivot can also include at least one flexure to rotatably couple the plurality of flexure support members to one another. The at least one flexure can have first and second flexible blades arranged in a cross configuration. The first and second flexible blades can be disposed in the flexure openings of the flexure support members, and braze material or other coupling material (e.g. an epoxy or other adhesive) deposited in the flexure openings can couple the first and second flexible blades to the flexure support members.

In one aspect, a flexural pivot precursor is disclosed. The flexural pivot precursor can comprise a plurality of flexure support members, each flexure support member having a plurality of flexure openings and a plurality of wells each in fluid communication with a respective flexure opening. The flexural pivot precursor can also include at least one flexure to rotatably couple the plurality of flexure support members to one another. The at least one flexure can have first and second flexible blades arranged in a cross configuration. The first and second flexible blades can be disposed in the flexure openings of the flexure support members.

A flexural pivot manufacturing system is also disclosed. The system can comprise a fixture having a bottom support and a top support coupled to the bottom support. The system can also comprise a plurality of flexural pivot support member workpieces coupled to the fixture. The plurality of flexural pivot support member workpieces can include a first flexural pivot support member workpiece supported by and coupled to the bottom support, and a second flexural pivot support member workpiece supported by and coupled to the top support. The top and bottom supports can facilitate formation of flexure openings and wells in fluid communication with the flexure openings extending into ends of the flexural pivot support member workpieces to form flexural pivot flexure support members. The top and bottom supports can also facilitate disposing at least one flexure in the flexure openings. The at least one flexure can have first and second flexible blades arranged in a cross configuration. In addition, the top and bottom supports can facilitate disposing braze or other coupling material in the wells to couple the at least one flexure to the flexural pivot flexure support members to provide for rotational movement of the flexural pivot flexure support members relative to one another.

In addition, a method for making a flexural pivot is disclosed. The method can comprise coupling a plurality of flexural pivot support member workpieces to a fixture, wherein a first flexural pivot support member workpiece is coupled to a bottom support of the fixture, and a second flexural pivot support member workpiece is coupled to a top support of the fixture. The method can also comprise coupling the top and bottom support to one another. The method can further comprise forming flexure openings and wells in fluid communication with the flexure openings extending into ends of the flexural pivot support member workpieces to form a plurality of flexural pivot flexure support members. The method can even further comprise disposing at least one flexure in the flexure openings of the plurality of flexural pivot flexure support members, wherein the at least one flexure has first and second flexible blades arranged in a cross configuration. The method can still further comprise disposing coupling material in the wells. Additionally, the method can comprise heating the coupling material sufficient to cause the coupling material to flow into the flexure openings to couple the at least one flexure to the flexural pivot flexure support members and thereby rotatably couple the plurality of flexural pivot flexure support members to one another. With respect to the coupling of the at least one flexure to the flexural pivot flexure support members, the method can alternatively comprise disposing an epoxy or other adhesive in the wells, wherein the epoxy or other adhesive comprises a viscosity sufficient to facilitate wicking of the epoxy or other adhesive into the flexure openings via capillary action.

One example of a flexural pivot <NUM> is illustrated in <FIG>. The flexural pivot <NUM> can comprise flexure support members rotatably coupled to one another. For example, the flexural pivot <NUM> can include a first flexure support member <NUM>, a second flexure support member <NUM> rotatably coupled to the first flexure support member <NUM> for relative rotation about a first axis <NUM>, and a third flexure support member <NUM> rotatably coupled to the second flexure support member <NUM> for relative rotation about a second axis <NUM>. The axes <NUM>, <NUM> can be orthogonal. Although three flexure support members <NUM>, <NUM>, <NUM> are illustrated, it should be recognized that a flexural pivot <NUM> can include only two flexure support members coupled to one another for relative rotation about only a single axis.

The flexural pivot <NUM> can be coupled to external structures to facilitate relative rotation of the structures about the first and second axes <NUM>, <NUM>. For example, the flexural pivot <NUM> can be coupled to and utilized with fast steering mirrors, which are commonly used in electro-optical sensors, directed energy systems, long range laser communications systems, telescopes, or other precision optics applications, and therefore may be included in laboratory-based systems, airborne line of sight stabilization systems, satellites, cameras, etc. Thus, one structure can be an optical bench of an electro-optical sensor, and the other structure can be a mirror. The external structures can be coupled to the first and third flexure support members <NUM>, <NUM> utilizing coupling interfaces such as openings or holes <NUM> (which can be threaded), slots, pins, studs, and other coupling interfaces.

The flexural pivot <NUM> can include flexures 140a-d (i.e., cross blade flexures) rotatably coupling the first, second and third flexure support members <NUM>, <NUM>, <NUM> to one another. For example, the flexures 140a-b can rotatably couple the first and second flexure support members <NUM>, <NUM> to one another, and the flexures 140c-d can rotatably couple the second and third flexure support members <NUM>, <NUM> to one another. Thus, the first and second flexure support members <NUM>, <NUM> can move relative to one another about the first axis <NUM>, and the second and third flexure support members <NUM>, <NUM> can move relative to one another about the second axis <NUM>, which can provide relative rotation of the first and third flexure support members <NUM>, <NUM> about two axes or in two degrees of freedom. Two or more flexures can be utilized for a given axis to provide stability for the flexure support members. The second flexure support member <NUM> moves in only a single degree of freedom with respect to each of the first and third flexure support members <NUM>, <NUM>. The second flexure support member <NUM> may be referred to as a coupler due to its intermediate relationship with respect to the first and third flexure support members <NUM>, <NUM> and function coupling the two-axis rotational movement of the flexural pivot <NUM>. In one aspect, the flexural pivot <NUM> can provide a frictionless pivot coupling between two bodies (i.e., external structures) that can support significant loads during high accelerations and allow large angular travel. In addition, the flexural pivot <NUM> can be designed such that the masses of all the moving parts are balanced at the same center of gravity. For example, the second flexure support member <NUM> or coupler can be configured so its center of gravity is at the intersection of both the first and second pivot axes <NUM>, <NUM>, which allows its weight to not affect the balancing of the supported or moving mass in both axes.

Each flexure 140a-d can have two or more flexible blades <NUM> arranged in a cross configuration. For example, the flexible blades <NUM> can have a C-shape or configuration. The flexible blades <NUM> can be oriented with the open sides of the C-shapes facing and oriented about <NUM> degrees relative to one another to achieve the cross blade configuration. A flexible blade <NUM> is shown isolated in <FIG>. The flexible blades <NUM> can have any suitable dimension, as the principles disclosed herein provide flexural pivot components that are scalable to accommodate a wide range of sizes and applications. In one example, a flexural pivot <NUM> can have an overall size dimension (e.g., length and/or width) of <NUM> (<NUM> inches), and the flexible blades <NUM> can have a thickness of <NUM> (<NUM> inches). The flexible blades <NUM> can be made of any suitable material. In some examples, the flexible blade <NUM> can be made of materials having relatively high yield and fatigue strength, such as steel (e.g., high-carbon spring stainless steel), or titanium (e.g., 6AI-4V).

Each of the first, second and third flexure support members <NUM>, <NUM>, <NUM> can have flexure openings <NUM>, <NUM>, which can be configured as slots to receive the flexible blades <NUM>. The flexure openings <NUM>, <NUM> can extend into ends of the first, second and third flexure support members <NUM>, <NUM>, <NUM>. In addition, each of the first, second and third flexure support members <NUM>, <NUM>, <NUM> can have wells <NUM>, <NUM> (e.g., braze or adhesive wells) in fluid communication with the flexure openings <NUM>, <NUM> to facilitate coupling the flexible members <NUM> to the flexure support members <NUM>, <NUM>, <NUM>. Braze material or another type of coupling material (e.g., epoxy or other adhesive) (not shown) can be disposed in the wells <NUM>, <NUM>. A braze material can be heated and caused to flow from the wells <NUM>, <NUM> into the flexure openings <NUM>, <NUM> about the flexible members <NUM> to couple the flexible members <NUM> to the first, second and third flexure support members <NUM>, <NUM>, <NUM>. For clarity, flexure openings <NUM>, <NUM> and wells <NUM>, <NUM> of the first, second and third flexure support members <NUM>, <NUM>, <NUM> are only identified on portions of the second and third flexure support members <NUM>, <NUM> in <FIG> and/or 1B. These features are shown in <FIG> and identified with the same reference numbers associated with each individually illustrated flexure support member. Using an epoxy or other adhesive to couple the flexible members <NUM> to the first, second and third flexure support members <NUM>, <NUM>, <NUM>, the adhesive can be selected as having a sufficient viscosity to facilitate wicking of the adhesive into the flexure openings <NUM>, <NUM> via capillary action. Although it is contemplated that various coupling materials can be used, the following detailed description and the examples presented will be illustrated using a braze material as the example coupling material. However, this is not intended to be limiting in any way.

The wells <NUM>, <NUM> can be located at ends of the flexure openings <NUM>, <NUM> (e.g., radially outward relative to the flexure openings <NUM>, <NUM>). This can locate the wells <NUM>, <NUM> proximate to or disposed about portions of the flexible blades <NUM> that are disposed in the flexure openings <NUM>, <NUM> to facilitate coupling the flexible blades <NUM> to the first, second and third flexure support members <NUM>, <NUM>, <NUM>. The flexible blades <NUM> can be disposed in the flexure openings <NUM>, <NUM>, which can be configured as slots, such that side walls of the flexure openings <NUM>, <NUM> are disposed on opposite sides of coupling portions 142a, 142b of the flexible blades <NUM>. For example, as shown in <FIG>, a flexible blade <NUM> can be disposed in the flexure opening <NUM> of the third flexure support member <NUM>, such that side walls of the flexure opening <NUM> are disposed on opposite sides of a coupling portion 142a of the blade. In addition, the same flexible blade <NUM> can be disposed in the flexure opening <NUM> of the second flexure support member <NUM>, such that side walls of the flexure opening <NUM> are disposed on opposite sides of a coupling portion 142b of the blade <NUM>. Each of the flexible blades <NUM> can be similarly disposed in the other flexure openings <NUM>, <NUM> of the flexure support members <NUM>, <NUM>, <NUM>. In some embodiments, the flexible blades <NUM> can extend at least partially into the wells <NUM>, <NUM>.

The wells <NUM>, <NUM> can have any suitable shape or configuration. For example, the wells <NUM>, <NUM> can comprise cylindrical openings oriented to extend along the radially outward ends of the flexure openings <NUM>, <NUM> or along ends 143a, 143b of the flexible blades <NUM>. In addition, the flexure openings <NUM>, <NUM> can be configured to facilitate a brazed coupling with the flexible blades <NUM> while maintaining braze material within the flexure openings <NUM>, <NUM> away from the free length or bending portion <NUM> between the coupling portions 142a, 142b of the flexible blades <NUM>. For example, the flexure openings <NUM>, <NUM> can "neck down" or narrow away from the wells <NUM>, <NUM>. This geometry of the flexure openings <NUM>, <NUM> combined with the presence of the flexible blade <NUM> can capture or limit the flow or capillary action of braze material away from the wells <NUM>, <NUM>. The side walls of the flexure openings <NUM>, <NUM> can therefore be configured to maintain or confine the braze material in the flexure openings <NUM>, <NUM> and prevent or limit braze material from contacting the bending portions <NUM> of the flexible blades <NUM>. The side walls defining the flexure openings <NUM>, <NUM> can be precisely formed to engage with the blades <NUM> and accommodate braze material and/or block braze material flow.

By brazing or capturing the coupling portions 142a, 142b of the flexible blade <NUM> within the flexure openings <NUM>, <NUM> with braze material originating proximate the outside ends 143a, 143b or edges of the flexible blades <NUM>, the bending portion <NUM> between the coupling portions 142a, 142b of the flexible blades <NUM> can be precisely controlled, which can provide repeatable and predictable performance of the flexural pivot <NUM>. In addition, with the braze material being remotely located from the bending portions <NUM> (i.e., not located at junctions of the bending portions and the flexure support members), braze material is kept away from the bending portions <NUM> (which are subject to fatigue), and stress concentrations in the bending portions <NUM> can be reduced or minimized. Thus, angular travel can be increased for the same bending portion length without failure of the blades. In addition, because the bending portion <NUM> of the blade <NUM> does not terminate at the braze material, the braze material does not experience bending stress. The flexural performance of the blades <NUM> are therefore not limited by the braze couplings with the flexure support members <NUM>, <NUM>, <NUM>. Although braze material is not illustrated in <FIG> for clarity in showing certain aspects of the present disclosure, the braze material can be located in the flexure openings <NUM>, <NUM> between the flexible blades <NUM> and the side walls of the flexure openings <NUM>, <NUM> in the flexure support members <NUM>, <NUM>, <NUM>. As illustrated (i.e., without braze material), <FIG> shows a flexural pivot precursor in accordance with one example of the present disclosure.

In one aspect, the bending portions <NUM> of the flexible blades <NUM> can be prevented from contacting adjacent components (e.g., another flexible blade <NUM> and/or a flexure support member <NUM>, <NUM>, <NUM> to which the flexible blade <NUM> is coupled) to facilitate smooth, unrestricted movement of the flexible blades <NUM> during operation. For example, the bending portions <NUM> of the flexible blades <NUM> can be recessed <NUM>, <NUM> on outer sides of the flexible blades <NUM> to prevent the bending portions <NUM> from contacting adjacent components. In other words, an outer edge or surface of the bending portion <NUM> may not be coplanar or flush with the outer edge or surfaces of the coupling portions 142a, 142b. In addition, the flexible blades <NUM> can have a C-shape or configuration to facilitate arranging two flexible blades <NUM> in a cross configuration while providing bending portions <NUM> that are offset from one another. For example, the recess <NUM> can be much larger than the recess <NUM>, thus effectively positioning the bending portion <NUM> laterally offset with respect to the coupling portions 142a, 142b. This configuration can maximize the lateral size of the coupling portions 142a, 142b to improve coupling integrity with the flexure support members <NUM>, <NUM>, <NUM>. As shown in <FIG>, the flexible blades <NUM> can be substantially identical.

In one aspect, the first, second and third flexure support members <NUM>, <NUM>, <NUM> can include travel stops 159a, 159b to mechanically limit a rotational range of motion of the flexible blades <NUM>. The opposing travel stops 159a, 159b of the flexure support members can be configured to contact one another at the rotational travel limits. The travel stops 159a, 159b can limit the range of motion to any suitable degree. Typically, the travel stops 159a, 159b will be configured to prevent excessive bending of the flexible blades <NUM> that may result in failure (e.g., yielding) of the blades. The travel stops 159a, 159b can have any suitable configuration or interface surface to contact opposing travel stops. The travel stops 159a, 159b can be defined at least partially by the outer side surfaces <NUM>, <NUM> of the flexure support members <NUM>, <NUM>, <NUM>.

<FIG> and <FIG> illustrate a flexural pivot manufacturing system <NUM> in accordance with an example of the present disclosure. The manufacturing system <NUM> can include a fixture <NUM> having a bottom support <NUM> and a top support <NUM>. The top and bottom supports <NUM>, <NUM> can be configured to facilitate manufacturing and assembly of a flexural pivot, such as the flexural pivot <NUM> described above. Thus, the manufacturing system <NUM> can include flexural pivot support member workpieces <NUM>', <NUM>', <NUM>' coupled to the fixture <NUM>. A complete flexural pivot <NUM> (excluding braze material) is shown in <FIG> and <FIG> to demonstrate how the fixture <NUM> can be used to facilitate certain manufacturing and assembly steps in a method for making a flexural pivot <NUM>. Thus, it should be recognized that flexural pivot support member workpieces <NUM>', <NUM>', <NUM>' can be at any suitable stage of manufacture when the fixture <NUM> is utilized. The first, second and third flexure support members <NUM>, <NUM>, <NUM> can be made of any suitable material, such as titanium or steel.

The workpieces <NUM>', <NUM>', <NUM>' for manufacturing the three flexure support members <NUM>, <NUM>, <NUM> can be coupled to and supported by the fixture <NUM>. For example, the flexural pivot support member workpiece <NUM>' that will form the first flexure support member <NUM> can be supported by and coupled to the top support <NUM>. The flexural pivot support member workpiece <NUM>' that will form the third flexure support member <NUM> can be supported by and coupled to the bottom support <NUM>. The flexural pivot support member workpiece <NUM>' that will form the second flexural pivot flexure support member <NUM> can be disposed between the other flexural pivot support member workpieces <NUM>', <NUM>'. The workpiece <NUM>' can be supported by and coupled to the top support <NUM> and/or the bottom support <NUM>. In the illustrated example, the flexural pivot support member workpiece <NUM>' that will form the second flexural pivot flexure support member <NUM> is coupled to the bottom support <NUM>. The flexural pivot support member workpieces <NUM>', <NUM>', <NUM>' can be coupled to the bottom and top supports <NUM>, <NUM> by fasteners <NUM>, <NUM> and/or pins <NUM>, which can utilize any suitable coupling interface, such as the holes or openings <NUM> and/or slots. In addition, the bottom and top supports <NUM>, <NUM> can be coupled to one another, such as by fasteners <NUM> and/or pins <NUM>. The pins <NUM>, <NUM> can be used to precisely position the top support <NUM>, the bottom support <NUM>, and/or the various flexural pivot support member workpieces <NUM>', <NUM>', <NUM>' relative to one another. Pivot flexure interface surfaces of the fixture <NUM>, such as the interface surface <NUM> of the bottom support <NUM>, can be configured to interface with outer (e.g., top and bottom) surfaces of the flexural pivot <NUM> to mount and support the workpieces <NUM>', <NUM>', <NUM>' during manufacture and assembly. In one aspect, the interface surface <NUM> can be recessed and sidewalls <NUM> of the recess can serve as locating or positioning features for the flexure support member workpieces <NUM>', <NUM>', <NUM>'.

The fixture <NUM> includes standoff spacers <NUM> located in the corners of the flexural pivot support member workpieces <NUM>', <NUM>', <NUM>' (i.e., adjacent to sides of the workpieces <NUM>', <NUM>', <NUM>' to position the top and bottom supports <NUM>, <NUM> relative to one another and thereby position the flexural pivot support member workpieces <NUM>', <NUM>', <NUM>' relative to one another. In other words, the standoff spacers <NUM> can form four legs located in four concave corners of the flexural pivot support member workpieces <NUM>', <NUM>', <NUM>'. The standoff spacers <NUM> can be associated with the top support <NUM> and/or the bottom support <NUM>. In the illustrated embodiment, the standoff spaces <NUM> are associated with the bottom support <NUM>. The top and bottom supports <NUM>, <NUM> of the fixture <NUM> have a plate or block configuration and the standoff spacers <NUM> are disposed between the plates or blocks. This fixture configuration of top and bottom supports and standoff spacers <NUM> can expose the ends of the flexural pivot support member workpieces <NUM>', <NUM>', <NUM>', which can facilitate formation of the flexure openings <NUM>, <NUM> and wells <NUM>, <NUM>, which is described below.

The top and bottom supports <NUM>, <NUM> of the fixture <NUM> can be configured to facilitate formation of the flexure openings <NUM>, <NUM>, described above with respect to <FIG>, to form the first, second and third flexure support members <NUM>, <NUM>, <NUM>. The flexure openings <NUM>, <NUM> can be formed in the workpieces <NUM>', <NUM>', <NUM>' in any suitable manner utilizing any suitable process or combination of processes. For example, the flexure openings <NUM>, <NUM> may be formed in the workpieces <NUM>', <NUM>', <NUM>' by a material removal process, such as machining. Example machining processes include electrical discharge machining (EDM), water jet cutting, milling, etc. A manufacturing process may be selected based on the design objectives, tolerance requirements, cost, etc. A wire EDM process may provide precise machining that can meet tight tolerances and accurately control the flexure openings <NUM>, <NUM>. In one aspect, utilizing a common fixture <NUM> to support the first, second and third flexure support member workpieces <NUM>', <NUM>', <NUM>' can establish and maintain precision mounting relationships during machining or material removal operations that form the flexure openings <NUM>, <NUM>. Thus, flexure openings <NUM>, <NUM> can be formed in the same fixture setup and at the same time to ensure proper alignment of the flexure openings <NUM>, <NUM> for the flexible blade <NUM>. This can minimize stresses induced in the blades <NUM> during assembly due to misalignment, which can provide predictable performance of the flexural pivot <NUM>. The cuts can be generally in radial directions or, in other words, radially inward and outward relative to the axes of rotation <NUM>, <NUM>. The flexure openings <NUM>, <NUM> and the wells <NUM>,<NUM> can be formed with the same material removal operation.

In one aspect, the flexure support members <NUM>, <NUM>, <NUM> and the fixture <NUM> can be designed to allow the assembly-level formation of the flexure openings <NUM>, <NUM> to ensure alignment of the flexure openings <NUM>, <NUM> for assembly with the flexible blades <NUM>. For example, with the first, second and third flexure support members <NUM>, <NUM>, <NUM> in the "assembled" relationship shown in <FIG>, projected profiles of the flexure openings <NUM>, <NUM> and/or the wells <NUM>, <NUM> can extend uninterrupted by adjacent flexure support members in directions parallel to an axis of rotation <NUM>, <NUM> associated with a given flexure 140a-d. In other words, the geometry of the first, second and third flexure support members <NUM>, <NUM>, <NUM> can be such that a line of sight along the flexure openings <NUM>, <NUM> and/or the wells <NUM>, <NUM> for a given flexure support member is not blocked by an adjacent or neighboring flexure support member. This attribute can facilitate manufacture of the flexure support members <NUM>, <NUM>, <NUM> coupled together in a common jig or fixture <NUM>, such as by wire EDM.

As an example, the flexure openings <NUM> in the flexure support member <NUM>, shown in <FIG> and <FIG>, can be made simultaneously with the same manufacturing processes, such as wire EDM. For example, holes in a top cross portion <NUM> of the flexure support member <NUM> can be formed (e.g., by drilling) as a starting location for a wire EDM process. The holes can be located across a gap or recess <NUM> from one another. The same drilling operation can form both holes. The holes can form the wells <NUM> or the wells can be finish machined by a wire EDM process. The wire for the EDM process can extend through both holes to machine both flexure openings <NUM> in the top cross portion <NUM> with the same wire EDM process at the same time. Because the flexure support member <NUM> is disposed in the assembled position during the machining processes, the flexure support member <NUM> can include a gap or recess <NUM> (<FIG>) that is configured to provide clearance for the drill, wire, etc. used to form the wells <NUM> and the flexure openings <NUM> in the top cross portion <NUM> of the second flexure support member <NUM>. This sort of clearance relationship between adjacent flexure support members and part features to be machined (e.g., flexure openings and wells) can be replicated throughout the pivot flexure to facilitate simultaneous fixturing and machining of such features in all three of the first, second and third flexure support members <NUM>, <NUM>, <NUM>.

Cutting or forming the flexure openings <NUM>, <NUM> in the same fixture setup can provide good alignment of the flexure openings. This can reduce or minimize displacement driven stresses in the blades due to misalignment of the flexure openings <NUM>, <NUM>. Once the flexure openings <NUM>, <NUM> have been formed, the flexure support members <NUM>, <NUM>, <NUM> can be removed from the fixture <NUM> and cleaned prior to final assembly where the flexure support members are again secured in the fixture <NUM> and receive the flexible blades <NUM> in the flexure openings <NUM>, <NUM>, as described above with respect to <FIG>.

The flexible blades can be manufactured utilizing any suitable process or technique, such as milling, EDM, waterjet machining, casting, forging, stamping, photochemical machining (PCM), laser cutting, etc. A wire EDM, PCM, and/or laser cutting process may be utilized to provide accurate control of the part geometry. Final surfaces may be achieved by grinding, honing, polishing, etc. to a desired geometric and/or dimensional tolerance, and/or surface finish.

The top and bottom supports <NUM>, <NUM> can be configured to facilitate disposing the flexible blades <NUM> in the flexure openings <NUM>, <NUM> to rotatably couple the first, second and third flexure support members <NUM>, <NUM>, <NUM> to one another. For example, the top and bottom supports (including standoff spacers <NUM>) can provide access to ends of the first, second and third flexure support members <NUM>, <NUM>, <NUM> to facilitate disposing the flexible blades <NUM> in the flexure openings <NUM>, <NUM> of the first, second and third flexure support members <NUM>, <NUM>, <NUM>. By providing sufficient space about the ends of the flexure support members <NUM>, <NUM>, <NUM>, the flexible blades <NUM> can be inserted into the flexure openings <NUM>, <NUM>. In addition, supporting the first, second and third flexure support members <NUM>, <NUM>, <NUM> in the fixture <NUM> can align the flexure openings <NUM>, <NUM> to facilitate stress-free assembly of the blades <NUM> prior to brazing.

With the flexure support members <NUM>, <NUM>, <NUM> fixtured or fixed and the flexible blades <NUM> disposed in the flexure openings <NUM>, <NUM> as illustrated in <FIG>, braze material can be disposed in the wells <NUM>, <NUM> to couple the flexible blades <NUM> to the flexure support members. This configuration can represent a flexural pivot precursor in accordance with one example of the present disclosure. As described herein, the top and bottom supports <NUM>, <NUM> can be configured to facilitate coupling the flexible blades <NUM> to the flexure support members <NUM>, <NUM>, <NUM>, such as by providing access to the ends of the flexure support members for putting braze material in the wells <NUM>, <NUM>. Any suitable type of braze material in any suitable configuration may be utilized. For example, braze material in wire form can be disposed in the wells <NUM>, <NUM>. Alternatively, braze material in foil form can be disposed about the ends of the flexible blades <NUM>. In this case, the braze material can be initially located in the wells <NUM>, <NUM> and/or in the flexure openings <NUM>, <NUM>.

With braze material disposed in the wells <NUM>, <NUM>, the braze material can be heated sufficiently to cause the braze material to flow (e.g., via capillary action) into the flexure openings <NUM>, <NUM> about the flexible blades <NUM> to couple the flexible blades to the flexure support members <NUM>, <NUM>, <NUM>. The braze material can be heated in any suitable manner, such as by disposing the manufacturing system <NUM> in a furnace. Thus, the same fixture <NUM> can be used to support the parts through a brazing operation. Brazing the flexible blades <NUM> to the flexure support members <NUM>, <NUM>, <NUM> in the same fixture <NUM> can ensure proper alignment of the blades <NUM> as they are brazed. The flexible blades <NUM> can therefore be brazed in a single brazing operation with no post-machining necessary. The principles disclosed herein can provide superior brazed connections than that available in COTS flexural pivots.

As indicated above, although brazing has been discussed herein as the exemplary way to couple the flexible blades to the flexure support members, such is not intended to be limiting in any way. For example, it is contemplated that the flexible blades can be coupled to the flexure support members using an epoxy or other adhesive, which can be injected into the wells. The epoxy or other adhesive can comprise a viscosity sufficient to cause the epoxy or other adhesive to wick into the flexure openings via capillary action. Those skilled in the art will recognize still other ways that the flexible blades can be coupled to the flexure support members.

It is noted that no specific order is required in the methods disclosed herein, though generally in some embodiments, method steps can be carried out sequentially.

It is to be understood that the examples set forth herein are not limited to the particular structures, process steps, or materials disclosed, the invention being defined in the appended claims, as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular examples only and is not intended to be limiting.

Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more examples. In the description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of the technology being described.

Claim 1:
A flexural pivot manufacturing system (<NUM>), comprising:
a fixture (<NUM>) having a bottom support (<NUM>) and a top support (<NUM>) coupled to the bottom support;
a plurality of flexural pivot support member workpieces (<NUM>', <NUM>', <NUM>') coupled to the fixture; and
standoff spacers (<NUM>) located adjacent sides of the plurality of flexural pivot support member workpieces to position the bottom support and the top support relative to one another and thereby position the plurality of flexural pivot support member workpieces relative to one another, the top support and the bottom support having a plate or block configuration and the standoff spacers being disposed between the top and bottom supports;
the plurality of flexural pivot support member workpieces including
a first flexural pivot support member workpiece (<NUM>') supported by and coupled to the bottom support,
a second flexural pivot support member workpiece (<NUM>') supported by and coupled to the top support, and
flexure openings (<NUM>, <NUM>) and wells (<NUM>, <NUM>) in fluid communication with the flexure openings extending into ends of the flexural pivot support member workpieces to form flexure support members, the wells comprising cylindrical openings,
wherein the top and bottom supports facilitate:
disposing at least one flexure (140a-d) in the flexure openings, wherein the at least one flexure has first and second flexible blades (<NUM>) arranged in a cross configuration and extending into the wells of the flexure support members, the cylindrical openings of the wells oriented to extend along ends of the flexible blades, and
disposing coupling material in the wells to couple the at least one flexure to the flexure support members to provide for rotational movement of the flexure support members relative to one another.