Patent Description:
The present disclosure is directed to specimen testing and, more particularly, to a system, method, and apparatus for automating residual seal force testing and/or compression friction measurement testing.

Since the early part of the <NUM>th century, containers (e.g., bottles, vials, etc.) with elastomeric closures and, in some cases, crimped caps have been a primary packaging system for parenteral (i.e., injectable) medicines. Parenteral products contained in such container package systems require a robust seal at the interface between the glass container and the elastomeric stopper to prevent contamination and product leakage. While the seal is established in the manufacturing process, it must withstand a variety of handling, processing, and storage conditions prior to use.

In some examples, container seal is composed of three major components - the glass container, an elastomeric closure (e.g., a rubber stopper), and a cap that secures the rubber stopper in the container, such as an aluminum cap. When a metal cap is used, typically an aluminum or aluminum alloy, the cap must be crimped onto the stopped container with a compressive force that will ensure sufficient mating of the container and elastomeric closure. In other examples, the cap is removed for other testing. Closure variables that affect the container seals include dimensional characteristics and tolerances, along with the mechanical properties of the closure components, including modulus, hardness, and compression set.

Manufacturers of parenteral containers are required to employ a quantitative method for measuring the force a closure exerts against the container after the initial seal is made and throughout the shelf life of the product. In the case of a closure that uses a metal cap, this force measured using a residual seal force ("RSF") test, while a compression friction ("CF") measurement test is used evaluate a glass container that is sealed using a plunger. A CF measurement test is sometimes called a glide test. While existing RSF and CF testers can measure the RSF and CF, such testing can be time consuming, tedious, and labor intensive. Therefore, it is desirable to provide a more accurate, more tolerant, and/or automated system, method, and apparatus for RSF and/or CF testing. <CIT> discloses an example of a test head suitable for a RSF tester.

Systems, methods, and apparatuses for testing are disclosed, substantially as illustrated by and described in connection with at least one of the figures. More particularly, systems, methods, and apparatuses are disclosed for determining the residual seal force and/or compression friction measurement for containers, particularly containers for parenteral pharmaceutical products.

The foregoing and other objects, features, and advantages of the devices, systems, and methods described herein will be apparent from the following description of particular embodiments thereof, as illustrated in the accompanying figures; where like or similar reference numbers refer to like or similar structures. The figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the devices, systems, and methods described herein.

References to items in the singular should be understood to include items in the plural, and vice versa, unless explicitly stated otherwise or clear from the text. Grammatical conjunctions are intended to express any and all disjunctive and conjunctive combinations of conjoined clauses, sentences, words, and the like, unless otherwise stated or clear from the context. Recitation of ranges of values herein are not intended to be limiting, referring instead individually to any and all values falling within the range, unless otherwise indicated herein, and each separate value within such a range is incorporated into the specification as if it were individually recited herein. In the following description, it is understood that terms such as "first," "second," "top," "bottom," "side," "front," "back," and the like are words of convenience and are not to be construed as limiting terms. For example, while in some examples a first side is located adjacent or near a second side, the terms "first side" and "second side" do not imply any specific order in which the sides are ordered.

As used herein, the terms "about," "approximately," "substantially," or the like, when accompanying a numerical value, are to be construed as indicating a deviation as would be appreciated by one of ordinary skill in the art to operate satisfactorily for an intended purpose. Ranges of values and/or numeric values are provided herein as examples only, and do not constitute a limitation on the scope of the described embodiments. The use of any and all examples, or exemplary language ("e.g.," "such as," or the like) provided herein, is intended merely to better illuminate the embodiments and does not pose a limitation on the scope of the embodiments. The terms "e.g.," and "for example" set off lists of one or more non-limiting examples, instances, or illustrations. No language in the specification should be construed as indicating any unclaimed element as essential to the practice of the embodiments.

As used herein, the term "and/or" means any one or more of the items in the list joined by "and/or. " As an example, "x and/or y" means any element of the three-element set {(x), (y), (x, y)}. In other words, "x, y, and/or z" means "one or more of x, y, and z.

As used herein, the terms "circuit" and "circuitry" includes any analog and/or digital components, power and/or control elements, such as a microprocessor, digital signal processor (DSP), software, and the like, discrete and/or integrated components, or portions and/or combinations thereof.

As used herein, the terms "compression rod" and "compression pin" as used herein, each mean a rigid structure configured to impart a compressive force upon a specimen positioned in a testing system. In the case of a CF test, for example, the compression pin can be used to compress the elastomeric closure within a rigidly-supported parenteral container, such as a vial.

As used herein, the terms "drivingly coupled," "drivingly coupled to," and "drivingly coupled with" as used herein, each mean a mechanical connection that enables a driving part, device, apparatus, or component to transfer a mechanical force to a driven part, device, apparatus, or component.

As used herein, the term "processor" means processing devices, apparatuses, programs, circuits, components, systems, and subsystems, whether implemented in hardware, tangibly embodied software, or both, and whether or not it is programmable. The term "processor" as used herein includes, but is not limited to, one or more computing devices, hardwired circuits, signalmodifying devices and systems, devices and machines for controlling systems, central processing units, programmable devices and systems, field-programmable gate arrays, application-specific integrated circuits, systems on a chip, systems comprising discrete elements and/or circuits, state machines, virtual machines, data processors, processing facilities, and combinations of any of the foregoing. The processor may be, for example, any type of general purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, an application-specific integrated circuit (ASIC). The processor may be coupled to, or integrated with a memory device.

As used herein, the term "memory" and/or "memory device" means computer hardware or circuitry to store information for use by a processor and/or other digital device. The memory and/or memory device can be any suitable type of computer memory or any other type of electronic storage medium, such as, for example, read-only memory (ROM), random access memory (RAM), cache memory, compact disc read-only memory (CDROM), electro-optical memory, magnetooptical memory, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically-erasable programmable read-only memory (EEPROM), flash memory, solid state storage, a computer-readable medium, or the like.

A quantitative method for measuring a closure force exerted against a container after sealing can be performed using a constant rate of compression testing machine. By exerting a slow, constant rate of compression on a sealed container, a stress vs. time curve can be generated to determine a residual seal force (RSF) measurement of a given closure seal in a specimen. The RSF measurement can be determined for a variety of containers with various closure sizes and shapes. RSF measurements, for example, can be used to indicate the security of the container's closure as part of a manufacturer's quality control. The initial force with which the closure compresses the container is a function of the vertical and horizontal crimping forces applied during application (e.g., crimping) of the aluminum cap; however, due to the viscoelastic relaxation behavior of rubber, the force of the closure pressing against the containers decays as a function of time, elastomer composition, and as a result of various processing procedures. In another example, a compression friction (CF) measurement test can be performed using the compression testing machine to qualify a glass container that is sealed using an elastomeric closure (e.g., a plunger). A CF measurement test is sometimes referred to as a glide test.

To evaluate a seal tightness, manufacturers sometimes use manual testing systems as part of their quality control processes to measure the RSF or the CF of a parenteral package created during a container-sealing process. Typically, manufacturers test small batches or volumes (e.g., lot or line samples) as part of its quality control efforts. Because RSF and CF testing is considered destructive testing (i.e., the product is no longer saleable), manufacturers may test only between <NUM>% and <NUM>% of the production, or about <NUM>% of the production. Further, operators, who are already busy with other production-related tasks, are only permitted a limited amount of time to perform each test (e.g., about <NUM>-<NUM> minutes per specimen). Automating the RSF and the CF testing processes, however, can increase the testing speed and the volume of product that can be tested. To automate RSF and CF testing, precautions must be taken to ensure that the specimen are properly loaded to the testing system to ensure accurate measurements.

<FIG> illustrates perspective view of an example testing system <NUM>, while <FIG> illustrates a perspective view of the load frame <NUM> of the example testing system <NUM> with portions omitted for clarity. The testing system <NUM> generally comprises a load frame <NUM>, a load cell <NUM> mounted to a crosshead <NUM> of the load frame <NUM>, a platen assembly <NUM> at a base structure <NUM> of the load frame <NUM>, and a controller <NUM>. As will be discussed, the platen assembly <NUM> is configured to support one or more specimens <NUM> during compression testing (e.g., RSF or CF testing), whether through a manual or automated process.

As best illustrated in <FIG>, the load frame <NUM> comprises a base structure <NUM>, one or more columns <NUM>, a moving crosshead <NUM>, and a top plate <NUM>. The load frame <NUM> serves as a high stiffness support structure against which the test forces react (e.g., compressive forces) during a test (e.g., a RSF test, compression friction measurement test, etc.). While the load frame <NUM> may be composed of a single column <NUM>, as illustrated, multiple columns <NUM> may be employed, for example, in a dual column arrangement. The base structure <NUM> generally serves to support the one or more columns <NUM> and a platen assembly <NUM> that supports the specimen <NUM>, while also housing various circuitry and components, such as a controller <NUM>.

The platen assembly <NUM> may be manually or automatically adjusted (or otherwise controlled) to move or transfer a specimen <NUM> to a testing position, which is typically aligned below the test head <NUM>, test apparatus, or other test accessory. The specimen <NUM> may be, for example, a container <NUM> for a parenteral pharmaceutical product as illustrated in <FIG>. As best illustrated in Detail A of <FIG>, in one example, the container <NUM> (e.g., a bottle with a flange <NUM>) defines an opening <NUM> and a flange <NUM>. An elastomeric closure <NUM> covers the opening <NUM>. A cap <NUM> is crimped under flange <NUM> and compresses the elastomeric closure <NUM> to seal the opening <NUM>. In another example, as best illustrated in Detail B of <FIG>, the cap <NUM> may be omitted whereby the elastomeric closure <NUM> fits within the opening <NUM> of the container <NUM> (e.g., a vial) and presses against the inner surface of the container <NUM> to seal the opening <NUM>. While the specimen <NUM> is illustrated as a container <NUM> with and without a flange <NUM> and/or cap <NUM>, other types of specimens <NUM> are also contemplated.

Each of the one or more columns <NUM> comprises a guide column and a ballscrew <NUM> that is drivingly coupled to an actuator <NUM>. A ballscrew <NUM> is a form of mechanical linear actuator that translates rotational motion (e.g., from an actuator <NUM>, such as a motor) to linear motion with little friction. In one example, the ballscrew <NUM> may include a threaded shaft that provides a helical raceway for ball bearings, which acts as a precision screw. As illustrated in <FIG>, the ballscrew <NUM> is housed within the one or more columns <NUM> between the base structure <NUM> and the top plate <NUM>. The actuator <NUM> that drives the ballscrew <NUM> is controlled via the controller <NUM>. A column cover <NUM> may be provided to protect the ballscrew <NUM> from dirt, grime, and damage, while also protecting the user from harm during operation. The testing system <NUM> comprises various sensors to monitor its operation. For example, the testing system <NUM> may include an upper limit switch <NUM> and a lower limit switch <NUM> to prevent the crosshead <NUM> from deviating from an acceptable range of motion along axis A. Upon triggering the upper limit switch <NUM> or the lower limit switch <NUM>, the controller <NUM> may stop (or reverse) the actuator <NUM> to prevent damage to the testing system <NUM> or the specimen <NUM>.

The crosshead <NUM> is mounted to both the guide column and the ballscrew <NUM> and supports the load cell <NUM>. The ballscrew <NUM> is driven (e.g., rotated) via an actuator <NUM>. Rotation of the ballscrew <NUM> drives the crosshead <NUM> up (away) or down (toward) relative to the base structure <NUM>, while the guide column provides stability to the crosshead <NUM>. The load cell <NUM> may be removably coupled to the crosshead <NUM> via one or more mechanical fasteners <NUM> (e.g., screws, bolts, socket head cap screws, etc.) to enable the operator to exchange the load cell <NUM> when desired. For example, the load cell <NUM> may become damaged, a different type of load cell <NUM> may be desired or needed, which can vary by test (e.g., RSF and CF testing).

The display device <NUM> (e.g., a touch screen display), control panel <NUM>, and/or remote control <NUM> (e.g., a handset) may be used by the operator to monitor and/or control operation of the testing system <NUM>. In some example, the control panel <NUM> and the remote control <NUM> may each provide one or more switches, buttons, or dials to control or adjust operation of the testing system <NUM> (e.g., an emergency stop button). The control panel <NUM> and the remote control <NUM> may further provide one or more status indicators (e.g., LEDs, lights, etc.) to provide a status of the testing system <NUM>. The remote control <NUM> may be wired or wireless.

To provide additional protection and increase safety, the load string <NUM> may be housed in an enclosure <NUM> that defines a test chamber <NUM>. The enclosure <NUM> may be fabricated from a transparent material (e.g., glass, plastic, Plexiglas, etc.) to enable the operator to observe the load string <NUM>. A door or access panel <NUM> may be provided to enable access to the test chamber <NUM> within the enclosure <NUM>. The load string <NUM> generally refers to the components installed between the moving crosshead <NUM> and the base structure <NUM> (or, where applicable, a fixed lower crosshead). Typically, the load string <NUM> includes the load cell <NUM>, the test head <NUM>, any adapters required to connect the components, and the specimen(s) <NUM> to be tested. Typically, for RSF testing, the load cell <NUM> is mounted on the crosshead <NUM>, a test head <NUM> with an anvil is mounted to the load cell <NUM>, and a specimen <NUM> is positioned on the base structure <NUM> (e.g., using a platen assembly <NUM>). Similarly, for CF testing, a load cell <NUM> is mounted on the crosshead <NUM>, a compression rod is mounted to the load cell <NUM>, and a specimen <NUM> is positioned on the base structure <NUM> (e.g., using a platen assembly <NUM>).

Operation of the testing system <NUM> may be automatically controlled and/or monitored via the controller <NUM>. The controller <NUM> may comprise a processor 150a and memory device 150b configured with executable instructions. The controller <NUM> is operably coupled to, and configured to control, the various actuators (e.g., the actuator <NUM> that drives the ballscrew <NUM>), sensors (e.g., load cell(s) <NUM>, upper and lower limit switches <NUM>, <NUM>), user interfaces (e.g., display device <NUM>, control panel <NUM>, and/or remote control <NUM>), etc..

During the RSF test, for example, the crosshead <NUM> moves down along Axis A of the load frame <NUM> (toward the base structure <NUM>) to apply compressive load to the specimen <NUM> via a test head <NUM>, test apparatus, or other test accessory that is coupled to the load cell <NUM>. The test head <NUM> may be, or include, an anvil (also known as a dorn) configured to contact and compress the one or more specimens <NUM>. The test head <NUM>, test apparatus, or other test accessory may be coupled directly to a coupler <NUM> of the load cell <NUM> or via a compression rod or pin.

The load cell <NUM> converts this load into an electrical signal that the testing system <NUM> measures via controller <NUM> and displays to the operator via display device <NUM>. In one example, the test head <NUM> may advance at a constant speed (e.g., about <NUM> inches/second). In other words, in this example, for every <NUM> inches the crosshead <NUM> travels along the column <NUM> (along Axis A), the controller <NUM> automatically records the force exerted by the specimen <NUM> in response to the movement (strain) imposed upon the specimen <NUM> by the test head <NUM>. The constant speed may be adjusted for a given specimen <NUM>. The controller <NUM> also automatically records the corresponding strain data. The resulting data set comprises a sequence of stress-strain measurements that can be graphed, which approximates a curve of predictable shape. In the case of RSF, an adequate seal may be determined by monitoring for an inflection point on resulting curve (e.g., indicating the elastomeric closure <NUM> has transitioned from flexing to rigid, thus sealing the opening <NUM>).

The test head <NUM> may be designed for RSF and/or CF testing. For example, the test head <NUM> may be a compression rod for CF testing or include an anvil for RSF testing, such as a test head with an adjustable, conforming anvil. As can be appreciated, certain tests may warrant a specific type of test head <NUM>. For example, the test head <NUM> used during RSF measurement may include an anvil that is sized and shaped to correspond to the size and shape of the closure of a parenteral container. Therefore, while the test head <NUM> is generally illustrated in <FIG> and <FIG> as being configured for RSF testing, a compression rod (and associated load cell) may instead be used for CF testing.

The test head <NUM> can be interchangeable to enable the testing system <NUM> to be used for various types of tests (e.g., RSF, CF, tensile, compression, flexure, etc.). In other words, the test head <NUM> may be configured to removably couple with the load cell <NUM> via, for example, a coupler <NUM> or other means to enable the operator to replace or interchange the test head <NUM> with another the test head <NUM>, test apparatus, or other test accessory. The coupler <NUM> may employ one or more of a collar coupling (e.g., a collar with one or more set pins or screws), clevis coupling, sleeve coupling, or a screw on coupling (e.g., a threaded rod). Therefore, while the coupler <NUM> is illustrated as a female collar coupler with set screws and/or set pins, other types of couplings are contemplated.

The one or more specimens <NUM> are supported on the base structure <NUM> by the platen assembly <NUM>. Akin to the test head <NUM>, certain tests may warrant a specific type of platen assembly <NUM>. For example, the platen assembly <NUM> used during RSF measurement may include one or more stations that are sized and shaped to correspond to the size and shape of the parenteral container <NUM> (or other specimen <NUM>). That that end, the platen assembly <NUM> may comprise an specimen plate 110a that is test specific or specimen specific, and a base plate 110b supported by the base structure <NUM> and configured to support the specimen plate 110a. The specimen plate 110a may be removably coupled to the base plate 110b to enable the operator to select a specimen plate 110a that is suitable for a particular test. In one example, the specimen plate 110a is a plate or table that is sized and shaped to support the one or more specimens <NUM> (e.g., via one or more recesses), while the base plate 110b may be a plate configured to support and/or secure the specimen plate 110a relative to the base structure <NUM>. In some examples, the specimen plate 110a is configured to move relative to the base plate 110b. For example, the specimen plate 110a may be configured to rotate or tilt relative to the base plate 110b to accommodate an approach angle of the test head <NUM> during compression.

To yield accurate RSF measurements, it is important that the test head <NUM> firmly contact the specimen <NUM> (e.g., the cap <NUM>) during a RSF test. This typically requires that the operator check to ensure that the specimen <NUM> is properly seated in the platen assembly <NUM> such that the flat surface of the cap <NUM> is flush with the contact point of the test head <NUM> (e.g., the anvil). In an automated approach, this introduces additional complications.

One option is to employ a sensor system (e.g., one or more imaging devices) to confirm a correct placement of the specimen <NUM>, however, sensor systems increase cost and complexity of the overall system testing system <NUM>. A lower cost, but robust, option is use a test head <NUM> with an anvil that conforms to the position of the specimen <NUM> by enabling both planar and radially motion of the anvil during the seating portion of the RSF compression test to ensure that the test head <NUM> firmly contacts the specimen <NUM> (e.g., at the cap <NUM>).

<FIG> illustrates a plan cross-sectional view of a first example test head <NUM> in accordance with aspects of this disclosure. As illustrated, the test head <NUM> generally comprises a housing <NUM>, an anvil <NUM>, a ball roller assembly <NUM>, and a retaining ring <NUM>. The ball roller assembly <NUM> is configured to provide a point of contact <NUM> between the housing <NUM> and the anvil <NUM> during a RSF test. In some example, the retaining ring <NUM> is positioned within the first cavity <NUM> and configured to maintain the anvil <NUM> at least partially within the first cavity <NUM>. During the RSF test, the compressive forces push the anvil <NUM> into the first cavity <NUM>. The retaining ring <NUM> is configured to maintain the anvil <NUM> at least partially within the first cavity <NUM> in the absences of such compressive forces. The retaining ring <NUM> also provides a limit on the radially pivot <NUM> of the anvil <NUM> within the first cavity <NUM>. The test head <NUM> defines a proximal end <NUM> having a first coupler <NUM> configured to engage with a second coupler <NUM> of the testing system <NUM> and a distal end <NUM> having a recess <NUM> configured to engage a specimen <NUM>. The recess <NUM> may be sized and shaped to engage a surface of the cap <NUM> of the specimen <NUM>. In some examples, an example of which is illustrated in <FIG>, a washer <NUM> can be positioned at the contact point between the anvil <NUM> and the retaining ring <NUM> to provide or adjust a limit on the radially pivot <NUM> of the anvil <NUM> within the first cavity <NUM>. Though not illustrated, the washer <NUM> can be similarly configured in connection with the other views of the test head <NUM>.

As illustrated, the anvil <NUM> is configured to float within the first cavity <NUM>, thereby allowing a surface of the anvil <NUM> conform to the surface of the cap <NUM>. In an automated process, for example, a plurality of specimens <NUM> may be preloaded and/or automatically fed to or by the platen assembly <NUM>. Such movement can result in a specimen <NUM> being improperly seated (e.g., crooked). The accuracy of the RSF measurements decreases when the contact between the anvil <NUM> and the cap <NUM> is not flush. Therefore, to ensure that the cap <NUM> of the specimen <NUM> is properly seated in the recess <NUM> of the anvil <NUM>, the anvil <NUM> is configured to move relative to the housing <NUM> in both a planar motion <NUM> (e.g., side-to-side) and to pivot radially <NUM> relative to the housing <NUM>.

In some examples, the housing <NUM> defines a first cavity <NUM> and the anvil <NUM> is positioned at least partially within the first cavity <NUM>. The outer diameter of the anvil <NUM> may be sized to allow for lateral movement in a plane of the anvil <NUM> within the first cavity <NUM>. In other words, the inner diameter of the first cavity <NUM> may be larger than the outer diameter of the anvil <NUM> by a predetermined distance (D) to allow for some play within the first cavity <NUM>. The predetermined distance (D) may be, for example, <NUM> to <NUM> millimeters. When the anvil <NUM> is centered in the first cavity <NUM>, as illustrated in <FIG>, half of the distance (D/<NUM>) is available on each side of the anvil <NUM> for the planar motion <NUM>.

The ball roller assembly <NUM> generally comprises a sphere <NUM>, a roller housing <NUM>, and a plurality of ball bearings <NUM>. The ball roller assembly <NUM> may be rated to support 180N of compressive load. The plurality of ball bearings <NUM> serve to reduce friction between the sphere <NUM> and the roller housing <NUM>. The ball roller assembly <NUM> may be positioned in a second cavity <NUM>. For example, the ball roller assembly <NUM> can be press fit into the second cavity <NUM>. In the illustrated example, the housing <NUM> defines a second cavity <NUM>, however, as will be described in connection with <FIG> where the anvil <NUM> may define the second cavity <NUM>, other arrangements are contemplated. The housing <NUM>, the anvil <NUM>, and/or the sphere <NUM> may be fabricated from a metal or a metal alloy, such as stainless steel.

<FIG> illustrate plan cross-sectional views of the first example test head of <FIG> in contact with a specimen <NUM> that is improperly seated at a first angle and a second angle, respectively. The ball roller assembly <NUM> provides a single point of contact <NUM> between the housing <NUM> and the anvil <NUM>. As illustrated, the ball roller assembly <NUM> enables the anvil <NUM> to move in a planar motion <NUM> relative to the housing <NUM>. During an RSF test, the anvil <NUM> can move in a planar motion <NUM> and/or <NUM> radial motion <NUM> such that the recess <NUM> of the anvil <NUM> is flush with the specimen <NUM>.

<FIG> illustrates a plan cross-sectional view of the first example test head with a concave region at the point of contact. Over time, the single point of contact <NUM> may create a wear point (e.g., a divot) on the anvil <NUM>. As can be appreciated, a divot could prohibit the anvil <NUM> from freely floating, thereby reducing accuracy of the RSF measurements. To mitigate wear, the anvil <NUM> may define a concave region <NUM> at the single point of contact <NUM> that corresponds to the surface of the sphere <NUM>, thereby increasing contact area with the ball roller assembly <NUM>. The concave region <NUM> may alternatively be positioned on the housing <NUM> when the ball roller assembly <NUM> is secured to the anvil (e.g., as illustrated in <FIG>).

<FIG> illustrates a plan cross-sectional view of a second example test head <NUM> in accordance with aspects of this disclosure, while <FIG> illustrate plan cross-sectional views of the second example test head <NUM> in contact with a specimen <NUM> that is improperly seated at a first angle and a second angle, respectively. The test head <NUM> of <FIG> is substantially the same as the test head <NUM> of <FIG> except that the anvil <NUM> defines the second cavity <NUM> for the ball roller assembly <NUM>. In this example, the ball roller assembly <NUM> is press fit into the second cavity <NUM> of the anvil <NUM>.

<FIG> illustrates a perspective view a third example test head <NUM> in accordance with aspects of this disclosure, while <FIG> illustrates a plan cross-sectional views of the third example test head taken along section A-A of <FIG>. The test head <NUM> of <FIG> is similar to test heads <NUM>, <NUM> in that it facilitates planar motion <NUM> and radial motion <NUM>, however, test head <NUM> splits the planar motion <NUM> and radial motion <NUM> into two separate mechanisms. Specifically, planar motion <NUM> is provided via a plurality of ball bearing assemblies <NUM> and radial motion <NUM> is provided via a ball roller assembly <NUM>.

The test head <NUM> generally comprises a first housing <NUM>, a second housing <NUM>, and an anvil <NUM>. The first housing <NUM> defines a first cavity <NUM> and the second housing <NUM> defining a second cavity <NUM>. The second housing <NUM> is positioned at least partially within the first cavity <NUM> and is configured to move in a planar motion <NUM> relative to the first housing <NUM>. An anvil <NUM> positioned at least partially within the second cavity <NUM> and configured to pivot radially <NUM> relative to the second housing <NUM>. As illustrated, the anvil <NUM> is configured to pivot radially <NUM> relative to the second housing <NUM> using a ball roller assembly <NUM>. The ball roller assembly <NUM> comprises a sphere <NUM> and a roller housing <NUM>.

A plurality of ball bearing assemblies <NUM> are provided to reduce friction between the surface of the first and second housings <NUM>, <NUM>. In some examples, as illustrated, the plurality of ball bearing assemblies <NUM> are press fit into cavities defined in the second housing <NUM>, however, the plurality of ball bearing assemblies <NUM> may instead be press fit into cavities defined in the first housing <NUM>. In some example, the ball roller assembly <NUM> may further comprises a plurality of ball bearings (not illustrated) between the sphere <NUM> and the roller housing <NUM>.

<FIG> is a flowchart representative of an example method <NUM> for performing an automated residual seal force RSF test in a testing system <NUM>. The testing system <NUM> comprises a load cell <NUM> configured to move along a column <NUM> toward and away from a base structure <NUM> via a crosshead <NUM>.

At step <NUM>, a plurality of specimens <NUM> are loaded to a specimen plate 110a. The plurality of specimens <NUM> are loaded to a specimen plate 110a may be loaded through a manual or automated process. The plurality of specimens <NUM> comprises a first specimen <NUM> and a subsequent specimen <NUM> (e.g., a second specimen <NUM>).

At step <NUM>, the specimen plate 110a is positioned in a first position that situates the first specimen <NUM> at a testing position of the testing system <NUM>. The specimen plate 110a can be positioned in a first position manually (e.g., by the operator before the test is commenced) or via an actuator.

At step <NUM>, the actuator <NUM> advances the crosshead <NUM> along the column <NUM> toward the base structure <NUM> to compress the first specimen <NUM>.

At step <NUM>, the processor 150a, which is operatively coupled to the load cell <NUM>, determines a residual seal force of the first specimen <NUM>.

At step <NUM>, the actuator <NUM> retracts the crosshead <NUM> along the column <NUM> away the base structure <NUM>.

At step <NUM>, the specimen plate 110a is moved in a second position that situates the subsequent specimen <NUM> at the testing position.

At step <NUM>, the actuator <NUM> advances the crosshead <NUM> along the column <NUM> toward the base structure <NUM> to compress the subsequent specimen <NUM>.

At step <NUM>, the processor 150a determines a residual seal force of the subsequent specimen <NUM>.

Steps <NUM> through <NUM> may be automatically repeated for each subsequent specimen <NUM> until each of the plurality of specimens <NUM> loaded to the specimen plate 110a is tested.

Claim 1:
A test head (<NUM>, <NUM>, <NUM>) for a residual seal force (RSF) testing system (<NUM>), the test head (<NUM>, <NUM>, <NUM>) comprising:
a housing (<NUM>) defining a first cavity (<NUM>);
an anvil (<NUM>) positioned at least partially within the first cavity (<NUM>);
a ball roller assembly (<NUM>) configured to provide a point of contact (<NUM>) between the housing (<NUM>) and the anvil (<NUM>) during a RSF test; and
a retaining ring (<NUM>) configured to maintain the anvil (<NUM>) at least partially within the first cavity (<NUM>),
characterized in that the anvil (<NUM>) is configured to move in a planar motion (<NUM>) relative to the housing (<NUM>).