Patent Description:
This disclosure relates generally to materials testing, and more particularly, to methods and apparatus to perform load measurements on multi-hinged devices, and in particular to a hinged device testing system according to appended claim <NUM>.

Reliability testing for an assembly, or moving components of an assembly, may involve repetitively performing intended and/or unintended movements of the components to verify that the components and/or assembly reliably operates for a defined minimum number of cycles of the movements. For example, reliability testing of a flexible substrate may involve repeatedly flexing the substrate in one or more ways, while testing for continued operation of the device and/or monitoring various modes of failure.

<CIT> discloses a folding apparatus for flexible material durability testing.

<CIT> discloses a flexible substrate testing system.

<CIT> discloses a durability testing device for a hinge of an automotive side door.

<CIT> discloses a foldable hidden type double bed.

Methods and apparatus to perform load measurements on multi-hinged devices are disclosed, substantially as illustrated by and described in connection with at least one of the figures, as set forth more completely in the claims.

Flexible specimens often include assemblies and/or devices that have constraint mechanisms, such as simple hinges, double hinges, elliptical mechanisms, and/or other forms of constraints. Conventional measurement systems are not capable of characterizing forces associated with flexible specimens that involve such constraint mechanisms, because conventional measurement systems are not able to fold such specimens without over-constraining the specimens (resulting in damage), and/or because the reaction forces produced by the constraint mechanisms are typically many orders of magnitude greater than the reaction forces produced by the flexible material specimen.

Disclosed example hinged device testing systems provide repetitive stress testing and/or load measurement for hinged devices having multiple hinges for <NUM> or more sections, while reducing or minimizing additional stress induced on the hinged device by the hinged device testing system itself. For example, some disclosed hinged device testing systems allow the specimen to be folded by the system while allowing the constraint device(s) of the specimen (e.g., hinge(s)) to determine the exact folding path of the specimen, thereby testing the specimen in the same manner as in the eventual intended use of the specimen.

Some disclosed hinged device testing systems include fixturing that provides repetitive folding and unfolding of a hinged device, such as a hinged mobile electronic device (e.g., a smartphone). In some examples, the testing systems are configured such that the hinge of the hinged device controls a folding and unfolding path of a foldable substrate, while forces on the foldable substrate are measured. Disclosed examples configure the fixturing, such as guiding of the moving parts, such that the fixturing does not create additional force on the hinge(s) of the hinged device as the sides of the hinged device are folded together or unfolded.

In some examples, the hinged device testing systems include a translation linkage to limit forces on the device that are not in the direction measured using the hinged device testing system. As an example, a translation linkage may translate lateral forces on the measured side(s) of the hinged device to forces in the direction of measurement (e.g., forces normal to a face of the hinged device, forces associated with resistance of the hinge to folding, etc.).

Disclosed examples of the hinged device testing systems include multiple dynamic, or moving, portions, and a stationary, load measuring portion. Examples of the dynamic portions include a rotary shaft which articulates corresponding drive arms. The drive arms each feature a slot in which a cam follower (e.g., a bearing) is free to travel radially along the drive arm. The bearings are each secured to a shared mounting plate that moves a portion of a hinged device that is attached to the mounting plate. The stationary, load measurement portion is affixed to a same base plate as the dynamic side. The stationary side features a static stationary mounting plate to which another portion of the hinged device is attached. In some examples, the stationary mounting plate is suspended above the base plate using parallel flexures. In addition to the parallel flexures, a load cell (e.g., including corresponding adapter components) connect the stationary mounting plate to the base plate.

In some examples, the stationary side also includes rigid mounting points, which are decoupled from the load measurement path, to which portions of the hinges may be attached to reduce or eliminate the forces of the hinges. By providing rigid mounting points for the constraint mechanisms of the specimen, disclosed examples are capable of highly sensitive measurements of the folding forces of the specimen because the reaction forces associated with the constraint mechanism are isolated from the load measurement.

Disclosed example hinged device testing systems are sufficiently versatile to accommodate a variety of constraint mechanisms, including hinges, double hinges, and mechanisms not yet contrived. Disclosed examples can accommodate different specimen sizes with little or no adjustment (e.g. <NUM> bends, <NUM> bends, etc.). Disclosed examples are capable of expansion to test multiple specimens at once by connecting the specimens to the same driveshaft. Furthermore, disclosed example testing systems are inexpensive.

Some disclosed hinged device testing systems may be configured or arranged to test and/or measure hinged devices having different folding directions, including double infold (e.g., two outer sections both fold toward a same side of a center section) and inner-outer fold (e.g., two outer sections fold toward opposite sides of a center section). To accommodate the different folding shapes that may be accomplished, the fixturing, support, and/or drive components may be shaped and/or positioned to avoid mutual physical interference and provide device-guided motion. For example, in some disclosed hinged testing device systems, one or more drive arms may have centers of rotation or pivot axes that are offset from being in alignment with the slot or guide path provided by the drive arm. Additionally or alternatively, the flexures and/or load cells may be positioned so as to provide accurate measurements without interfering with the paths of motion of the device under test and/or the drive arms.

<FIG> illustrate an example hinged device test system <NUM> to perform mechanical property testing on a multi-hinged device <NUM>. The example multi-hinged device <NUM> may be an electronic or other device having two or more hinges 104a, 104b allowing at least a first portion <NUM>, a second portion <NUM>, and a third portion <NUM> of the hinged device <NUM> to at least partially fold. In the example of <FIG>, the second portion <NUM> and the third portion <NUM> of the multi-hinged device <NUM> are configured to fold in a double infold arrangement, in which both portions <NUM>, <NUM> fold toward a same side of the center portion <NUM>.

The system <NUM> of <FIG> is configured to repeatedly fold and unfold the hinged device <NUM> to measure forces associated with the folding and unfolding (e.g., resistive forces, spring forces, etc.). To measure the folding forces of the second portion <NUM> and the third portion <NUM> separately, the example system <NUM> may be controlled to fold the portion <NUM> while measuring the forces, and subsequently measuring the portion <NUM> while measuring the forces. <FIG> illustrates the multi-hinged device <NUM> and the folding path of the second portion <NUM>, and <FIG> illustrates the multi-hinged device <NUM> and the folding path of the third portion <NUM> while the second portion <NUM> is already in a folded position.

The example system <NUM> includes a first plate <NUM>, a second plate <NUM>, a third plate <NUM>, one or more first cam followers <NUM> coupled to the second plate <NUM>, one or more second cam followers <NUM> coupled to the third plate <NUM>, one or more first drive arms <NUM>, one or more second drive arms <NUM>, a first actuator <NUM> configured to drive the one or more first drive arms <NUM>, a second actuator <NUM> configured to drive the one or more second drive arms <NUM>, one or more load cells <NUM>, and a translation linkage <NUM>. The system <NUM> may include additional features, such as structural support or framing, processing circuitry, communications and/or input/output (I/O) circuitry, and/or any other components.

The first plate <NUM> has a first surface <NUM> to which the first portion <NUM> of the hinged device <NUM> is attached or affixed, and held stationary with respect to the first surface <NUM>. The second plate <NUM> has a second surface <NUM> to which the second portion <NUM> of the hinged device <NUM> is attached or affixed, and held stationary with respect to the second surface <NUM>. The third plate <NUM> has a third surface <NUM> to which the third portion <NUM> of the hinged device <NUM> is attached or affixed, and held stationary with respect to the third surface <NUM>. Adjacent ones of the plates <NUM>, <NUM>, <NUM> are separated by respective gaps, which are bridged by the hinges 104a, 104b.

As illustrated in <FIG>, the first drive arm(s) <NUM> moves the corresponding cam follower(s) <NUM> to cause the second plate <NUM> to rotate about a pivot axis of the hinge 104a of the hinged device <NUM>. The actuator <NUM> rotates the drive arm(s) <NUM> to cause the second plate <NUM> to move the second portion <NUM> of the hinged device <NUM> from the first position (shown in solid lines) toward the first portion <NUM> in the folded position (shown in broken lines). The drive arm(s) <NUM> allow motion of the cam follower(s) <NUM> along slot(s) defined by the drive arm(s) <NUM> so that the system <NUM> limits or eliminates force on the first portion <NUM> of the hinged device <NUM> by the weight of the second plate <NUM> or the drive arm(s) <NUM>, such that the measured force on the first portion <NUM> of the hinged device <NUM> is completely determined by the actuation of the hinge 104a.

In some examples, the actuator <NUM> may be a motor attached to the drive arm(s) <NUM> to rotate the drive arm(s) <NUM> about a pivot of the drive arm(s) <NUM>. Additionally or alternatively, the drive arm(s) <NUM> may be actuated manually.

As illustrated in <FIG>, when the second portion <NUM> is in the folded position, the second drive arm(s) <NUM> move the corresponding cam follower(s) <NUM> to cause the third plate <NUM> to rotate about a pivot axis of the hinge 104b of the hinged device <NUM>. The actuator <NUM> rotates the second drive arm(s) <NUM> to cause the third plate <NUM> to move the third portion <NUM> of the hinged device <NUM> from the first position (shown in solid lines) toward the first portion <NUM> in the folded position (shown in broken lines). The drive arm(s) <NUM> allow motion of the cam follower(s) <NUM> along slot(s) defined by the drive arm(s) <NUM> so that the system <NUM> limits or eliminates force on the first portion <NUM> of the hinged device <NUM> by the weight of the third plate <NUM> or the drive arm(s) <NUM>, such that the measured force on the first portion <NUM> of the hinged device <NUM> is completely determined by the actuation of the hinge 104b.

In some examples, the actuator <NUM> may be a motor attached to the drive arm(s) <NUM> to rotate the drive arm(s) <NUM> about a pivot of the drive arm(s) <NUM>.

The load cell <NUM> measures loads on the first plate <NUM> while the actuator <NUM> moves the second plate <NUM> and while the actuator <NUM> moves the third plate <NUM>. In particular, the load cell <NUM> measures stress (e.g., folding force) on the hinged device <NUM> as the hinged device <NUM> is folded by measuring load exerted by the first portion <NUM> of the hinged device <NUM> onto the first plate <NUM>.

The translation linkage <NUM> limits movement of the first plate <NUM> in directions other than the direction in which the load cell <NUM> is loaded by the first plate <NUM>. For example, if the load cell <NUM> is configured to measure loads in a direction perpendicular to the plane of the first surface <NUM>, the translation linkage <NUM> limits movement of the first plate <NUM> in directions parallel to the plane of the first surface <NUM> while permitting load to be transferred from the first plate <NUM> to the load cell <NUM>. An example translation linkage <NUM> may include one or more four-bar linkages coupled to a frame that is fixed with respect to the load cell <NUM>. In some other examples, the translation linkage <NUM> includes one or more flexures. In some examples, the translation linkage <NUM> is further limited in a direction toward the load cell <NUM> to prevent overloading of the load cell <NUM>. For example, a stopping point may be attached to the frame to prevent movement of the four-bar linkage(s) and the first plate <NUM> toward the load cell <NUM> beyond the stopping point.

In operation, the example load cell <NUM> may be biased or offset after securing the hinged device <NUM> to the first plate <NUM>, the second plate <NUM>, and the third plate <NUM> to subtract a preload from the test measurements. For example, the preload on the load cell <NUM> may occur due to the weight of the first plate <NUM>, the weight of translation linkage <NUM>, and/or the weight of the first portion <NUM> and/or the hinges 104a, 104b of the hinged device <NUM> on the first plate <NUM>. By determining the preload on the load cell <NUM>, the load cell <NUM> can be calibrated or offset to measure the stress on the hinged device <NUM> during folding and unfolding.

<FIG> illustrate an example hinged device test system <NUM> to perform mechanical property testing on a multi-hinged device <NUM> in which the hinges 204a, 204b fold toward opposite sides of the device <NUM>. Like the multi-hinged device <NUM> of <FIG>, the example multi-hinged device <NUM> includes a first portion <NUM>, a second portion <NUM> connected to the first portion <NUM> via a first hinge 204a, and a third portion <NUM> connected to the first portion via a second hinge 204b. However, the example third portion <NUM> is configured to fold to an opposite side of the first portion <NUM> than the second portion <NUM> (e.g., an inner-outer fold).

The example system <NUM> of <FIG> is similar to the example system <NUM> of <FIG>, except that the third plate <NUM> is configured on to connect to a different side of the third portion <NUM> of the device <NUM> to fold the third portion <NUM> toward an opposite side of the first portion <NUM> from the second portion <NUM>.

In the example of <FIG>, the load cell <NUM> may be configured to measure loads in a first direction when folding the second portion <NUM> towards the first side of the first portion <NUM>, and measure loads in a second direction when folder the third portion <NUM> towards the second side of the first portion <NUM>.

<FIG> is a block diagram of an example implementation of the hinged device test systems <NUM>, <NUM> of <FIG>, <FIG>, and/or 2B. As illustrated in <FIG>, the hinged device test system <NUM> includes a test fixture <NUM> and a computing device <NUM>.

The example computing device <NUM> may be a general-purpose computer, a laptop computer, a tablet computer, a mobile device, a server, an all-in-one computer, and/or any other type of computing device. The computing device <NUM> of <FIG> includes a processor <NUM>, which may be a general-purpose central processing unit (CPU). In some examples, the processor <NUM> may include one or more specialized processing units, such as FPGA, RISC processors with an ARM core, graphic processing units, digital signal processors, and/or system-on-chips (SoC). The processor <NUM> executes machine-readable instructions <NUM> that may be stored locally at the processor (e.g., in an included cache or SoC), in a random access memory <NUM> (or other volatile memory), in a read-only memory <NUM> (or other non-volatile memory such as FLASH memory), and/or in a mass storage device <NUM>. The example mass storage device <NUM> may be a hard drive, a solid-state storage drive, a hybrid drive, a RAID array, and/or any other mass data storage device. A bus <NUM> enables communications between the processor <NUM>, the RAM <NUM>, the ROM <NUM>, the mass storage device <NUM>, a network interface <NUM>, and/or an input/output interface <NUM>.

An example network interface <NUM> includes hardware, firmware, and/or software to connect the computing device <NUM> to a communications network <NUM> such as the Internet. For example, the network interface <NUM> may include IEEE <NUM>. X-compliant wireless and/or wired communications hardware for transmitting and/or receiving communications.

An example I/O interface <NUM> of <FIG> includes hardware, firmware, and/or software to connect one or more input/output devices <NUM> to the processor <NUM> for providing input to the processor <NUM> and/or providing output from the processor <NUM>. For example, the I/O interface <NUM> may include a graphics-processing unit for interfacing with a display device, a universal serial bus port for interfacing with one or more USB-compliant devices, a FireWire, a field bus, and/or any other type of interface. The example extensometer system <NUM> includes a display device <NUM> (e.g., an LCD screen) coupled to the I/O interface <NUM>. Other example I/O device(s) <NUM> may include a keyboard, a keypad, a mouse, a trackball, a pointing device, a microphone, an audio speaker, a display device, an optical media drive, a multi-touch touch screen, a gesture recognition interface, a magnetic media drive, and/or any other type of input and/or output device.

The computing device <NUM> may access a non-transitory machine-readable medium <NUM> via the I/O interface <NUM> and/or the I/O device(s) <NUM>. Examples of the machine-readable medium <NUM> of <FIG> include optical discs (e.g., compact discs (CDs), digital versatile/video discs (DVDs), Blu-ray discs, etc.), magnetic media (e.g., floppy disks), portable storage media (e.g., portable flash drives, secure digital (SD) cards, etc.), and/or any other type of removable and/or installed machine-readable media.

The test fixture <NUM> is coupled to the computing device <NUM>. In the example of <FIG>, the test fixture <NUM> is coupled to the computing device via the I/O interface <NUM>, such as via a USB port, a Thunderbolt port, a FireWire (IEEE <NUM>) port, and/or any other type serial or parallel data port. In some examples, the test fixture <NUM> is coupled to the network interface <NUM> and/or to the I/O interface <NUM> via a wired or wireless connection (e.g., Ethernet, Wi-Fi, etc.), either directly or via the network <NUM>.

The test fixture <NUM> includes a frame <NUM>, a load cell <NUM>, material fixtures <NUM>, and a control processor <NUM>. The frame <NUM> provides rigid structural support for the other components of the test fixture <NUM> that perform the test. The load cell <NUM> may implement the load cell <NUM> of <FIG>, <FIG>, and/or 2B, and measures force applied to a material under test (e.g., the hinged device <NUM>) by an actuator <NUM> via grips <NUM> (e.g., the plates <NUM>, <NUM>, <NUM>).

The actuator <NUM> applies force to the material under test and/or forces displacement of the material under test, while the grips <NUM> grasp or otherwise couple the material under test to the actuator <NUM>.

Example actuators that may be used to provide force and/or motion of a component of the test fixture <NUM> include electric motors, pneumatic actuators, hydraulic actuators, piezoelectric actuators, relays, and/or switches. While the example test fixture <NUM> uses a motor, such as a servo or direct-drive linear motor, other systems may use different types of actuators. For example, hydraulic actuators, pneumatic actuators, and/or any other type of actuator may be used based on the requirements of the system.

The example grips <NUM> include platens, clamps, and/or other types of fixtures, depending on the mechanical property being tested and/or the material under test. The grips <NUM> may be manually configured, controlled via manual input, and/or automatically controlled by the control processor <NUM>.

The test system <NUM> may further include one or more control panels <NUM>, including one or more input devices <NUM>. The input devices <NUM> may include buttons, switches, and/or other input devices located on an operator control panel. For example, the input devices <NUM> may include buttons that control the actuator <NUM> to jog (e.g., position) the grips <NUM> to a desired position, switches (e.g., foot switches) that control the grips <NUM> to close or open (e.g., via another actuator), and/or any other input devices to control operation of the testing test fixture <NUM>.

The example control processor <NUM> communicates with the computing device <NUM> to, for example, receive test parameters from the computing device <NUM> and/or report measurements and/or other results to the computing device <NUM>. For example, the control processor <NUM> may include one or more communication or I/O interfaces to enable communication with the computing device <NUM>. The control processor <NUM> may control the actuator <NUM> to move in a given direction and/or to control the speed of the actuator <NUM>, control the fixture(s) <NUM> to grasp or release a material under test, and/or receive measurements from the displacement transducer <NUM>, the load cell <NUM> and/or other transducers.

The example control processor <NUM> is configured to implement a repetitive motion testing process in which a test specimen (e.g., the hinged device <NUM>) is subjected to testing in the test fixture <NUM>. For example, to measure stress on the hinged device <NUM> during or after a series of folding and unfolding motions, the control processor <NUM> controls the actuator <NUM> to move the grips <NUM> (e.g., the first, second, and third plates <NUM>, <NUM>, <NUM>) while monitoring the load cell <NUM> to measure stress on the hinged device <NUM>. In some examples, the control processor <NUM> monitors a motor encoder of the actuator <NUM> to determine a folding angle and/or establish a folding degree-per-pulse ratio.

<FIG> is a perspective view of an example implementation of the hinged device test system <NUM> of <FIG> configured to perform load measurement testing on a multi-hinged device in which the hinges fold toward a same side of the device. In the example of <FIG>, the translation linkage <NUM> includes multiple flexures <NUM> attached to brackets <NUM>, which support the flexures <NUM> at the desired height. The example system <NUM> is illustrated in <FIG> without the multi-hinge device <NUM>.

<FIG> is a perspective view of an example implementation of the hinged device test system <NUM> of <FIG> configured to perform load measurement testing on a multi-hinged device <NUM> in which the hinges fold toward opposite sides of the device. As illustrated in <FIG>, the translation linkage <NUM> (e.g., flexures <NUM> and brackets <NUM>) and the load cell(s) <NUM> are positioned to the sides of the first plate <NUM>, such that the translation linkage <NUM> and the load cell(s) <NUM> do not interfere with the path of motion of the second plate <NUM>. The first plate <NUM> may include extensions <NUM> to couple the first plate to the flexures <NUM> and/or the load cell(s) <NUM>.

The example of <FIG> may implement either of the example test systems <NUM>, <NUM> of <FIG>, <FIG> by changing the position of the pivot point of the pivot the drive arm <NUM> via another bracket <NUM>. By using the upper position <NUM>, the drive arm <NUM> is configured to test inner-outer folding devices (e.g., the system <NUM>). In contrast, by using the lower position <NUM>, the drive arm <NUM> is configured to test double infold devices (e.g., the system <NUM>). While multiple actuators <NUM> and corresponding shafts are illustrated as driving the third plate <NUM> in the example of <FIG>, only one of the illustrated actuators <NUM> would be used in a given configuration.

As illustrated in <FIG>, drive arms <NUM> may be coupled to the actuator <NUM> to rotate the third plate <NUM> via a cam follower <NUM> attached to the third plate <NUM>. The drive arms <NUM> are offset (e.g., L-shaped) to align the axis of rotation of the third plate <NUM> with the device under test.

<FIG> illustrate side views of different orientations of an example drive arm <NUM> that may be used to implement the drive arms <NUM>, <NUM> of <FIG>, <FIG>, and/or <FIG>, and corresponding orientations of the second or third plates <NUM>, <NUM> attached to a cam follower <NUM>, <NUM>. The example drive arm <NUM> has a drive arm pivot axis <NUM>, while the plate <NUM>, <NUM> has a plate pivot axis <NUM> that is controlled by the hinge pivot axis of the multi-hinged device <NUM>, <NUM>.

<FIG> is a block diagram illustrating an example arrangement of plates, support flexures, and load cells that may be used to implement the hinged device test systems <NUM>, <NUM> of <FIG>, <FIG>, and/or <FIG>. <FIG> is a top view of an example arrangement of the hinged device test system of <FIG>, <FIG>, and/or <FIG>.

As illustrated in <FIG>, the center plate <NUM> may be supported on both sides by flexures <NUM> and flexure mounting brackets <NUM>, which are coupled to the extensions <NUM> (e.g., tabs) of the center plate <NUM> so as to locate the flexures <NUM> out of the folding paths of the folding plates <NUM>, <NUM>. Similarly, the example of <FIG> includes load cells <NUM> on each side of the center plate <NUM> to accurately measure the forces on the center plate <NUM> during folding.

The example actuators <NUM>, <NUM> may be coupled to pivot the drive arms <NUM>, <NUM> on either side of the plates <NUM>, <NUM> via respective shafts <NUM>, <NUM>.

<FIG> illustrate an example folding arrangement of drive arms <NUM>, <NUM> for the hinged device test system <NUM> of <FIG>, <FIG>, and/or <FIG> for a multi-hinged device configured for a double infold.

<FIG> illustrate an example folding arrangement of drive arms <NUM>, <NUM> for the hinged device test system <NUM> of <FIG>, <FIG>, and/or <FIG> for a multi-hinged device configured for an inner-outer fold.

Claim 1:
A hinged device testing system (<NUM>), comprising:
a first plate (<NUM>) comprising a first surface (<NUM>) configured to hold stationary a first portion (<NUM>) of a hinged device (<NUM>) under test;
a second plate (<NUM>) comprising a second surface (<NUM>) configured to hold a second portion (<NUM>) of the hinged device under test, the second portion of the hinged device coupled to the first portion via a first hinge (104a) having a first folding radius;
a third plate (<NUM>) comprising a third surface (<NUM>) configured to hold a third portion (<NUM>) of the hinged device under test, the third portion of the hinged device coupled to the first portion via a second hinge (104b) having a second folding radius;
a first cam follower (<NUM>) coupled to the second plate;
a first drive arm (<NUM>) configured to move the first cam follower to cause the second plate to rotate about a first hinge pivot axis of the first hinge;
a first actuator (<NUM>) configured to rotate the first drive arm;
a second cam follower (<NUM>) coupled to the third plate;
a second drive arm (<NUM>) configured to move the second cam follower to cause the third plate to rotate about a second hinge pivot axis of the second hinge;
a second actuator (<NUM>) configured to rotate the second drive arm; and
a load cell (<NUM>) configured to measure first loads on the first plate while the first actuator moves the second plate and to measure second loads on the first plate while the second actuator moves the third plate.