Universal modular test fixture

Abstract

A modular test fixture configured to quickly support different configurations of test samples for testing.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 901122, filed September 16, 2019, and U.S. Provisional Application No. 62 / 914274, filed October 11, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Embodiments of this disclosure relate to modular test fixtures with different configurations, which can be used for a variety of mechanical tests on samples. Background Technology

[0004] Test fixtures are used to support samples being tested on a testing machine (e.g., a universal testing machine or UTM). If the samples being tested have similar configurations or shapes (e.g., a tensile test of a rod), test fixtures configured to support only samples of similar shapes (e.g., clamping rods) are used on the testing machine. However, if samples with different configurations and / or different types of tests are to be performed (e.g., needle cap removal force test, flange fracture strength test, etc.), it is generally necessary to replace the test fixture (gripper, etc.) supporting the sample during testing to accommodate the different configurations of the sample and / or test. Changing or reconfiguring test fixtures between tests is time-consuming and inefficient. In this case, it is desirable to use a test fixture configured to support samples of different sizes, whose configuration allows the desired type of force to be applied to the sample with minimal variation in the test fixture. Embodiments of this disclosure include modular test fixtures that can be easily adapted or configured to support different configurations of samples for different types of tests on a testing machine. However, the scope of this disclosure is defined by the appended claims and not by the ability to solve any particular problem. Attached Figure Description

[0005] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments of this disclosure and, together with the specification, serve to explain the principles of this disclosure. Each embodiment disclosed herein may include one or more features described in conjunction with any other disclosed embodiment.

[0006] Figures 1A to 1D Different views of the exemplary test fixture of this disclosure are shown.

[0007] Figure 2A The sample holder with the top plate removed is shown. Figure 1A Top view of the top plate of the test fixture.

[0008] Figure 2B The diagram shows a sample holder coupled thereto.Figure 2A The top plate.

[0009] Figure 3 This is a perspective view of an exemplary sample holder.

[0010] Figure 3A and 3B An exploded view of an exemplary sample holder with a top plate is shown.

[0011] Figures 4A to 4C Showing with Figures 1A to 1D The exemplary test fixture is used with different views of the finger component.

[0012] Figures 5A to 5E An example of a replacement part is shown.

[0013] Figure 6 Exemplary methods of this disclosure are shown. Detailed Implementation

[0014] This disclosure describes exemplary test fixtures that can be used in conjunction with a Universal Test Machine (UTM), such as the Instron test machine. Although the principles of the present disclosure are described with reference to test fixtures for UTM, it should be understood that this disclosure is not limited thereto. Rather, the disclosed test fixtures can be used alone or in conjunction with any type of device or machine (for any application). Generally, relative terms used in this disclosure, such as “about,” “substantially,” or “approximately,” are used to indicate possible deviations of ±10% of the stated values. Any implementation described herein as exemplary should not be construed as preferred or advantageous over other implementations. Rather, the term “exemplary” is used in an illustrative or explanatory sense.

[0015] Figures 1A to 1C Different perspective views of the currently disclosed exemplary test fixture (test apparatus) 100 are shown, and Figure 1D A bottom view of the test fixture 100 is shown. In the following description, reference will be made to... Figures 1A to 1D In the embodiments shown in these figures, the test fixture 100 includes a top plate 10, a middle plate 30, and a bottom plate 50 spaced apart in the z-direction (see Figure 10). Figures 1A to 1C (The XYZ coordinates in the diagram). In the following description, the z-direction will be referred to as the vertical direction, the end marked "A" will be referred to as the front end of the test fixture 100, and the end marked "B" will be referred to as its rear end. However, it should be noted that the terms "front," "rear," "top," and "bottom" are used merely for convenience and are not mandatory.

[0016] like Figures 1A to 1DAs shown, the top, middle, and bottom plates 10, 30, 50 can be generally planar structures extending in the x-y plane, and thus can each be substantially parallel to one another. While not required, in some embodiments, as shown, the top, middle, and bottom plates 10, 30, and 50 can have a generally rectangular shape (in the XY plane). The top, middle, and bottom plates 10, 30, and 50 can be formed of any material and can be formed in any suitable manner. While not required, in some embodiments, these plates 10, 30, 50 can comprise a plastic or polymeric material (e.g., nylon, glass-filled polyamide, epoxy, polycarbonate, etc.). These plates can be formed or manufactured in any suitable manner (machined, molded, etc.). In some embodiments, some or all of these plates can be manufactured using 3D printing. In some embodiments, one or more sheets of reinforcing material can be embedded within the top plate 10, middle plate 30, and / or bottom plate 50. For example, one or more of the plates can include a printed sheet of metal or a sheet of fiberglass within an otherwise 3D printed polymeric plate.

[0017] The top, middle, and bottom plates 10, 30, 50 can be coupled together by, for example, posts 12, 14, 16 proximate their corners and a movable (e.g., rotating screw) assembly 20. As shown in the figures, the posts 12 and 14 can couple the plates 10, 30, 50 together at the front end A of the test fixture 100, and the post 16 and movable assembly 20 can couple the plates 10, 30, 50 together at the rear end B of the test fixture 100. As shown in the figures, the posts 12, 14, and 16 can be cylindrical structures having a diameter (in the XY plane). However, this is merely exemplary. In general, these posts 12, 14, and 16 can have any suitable configuration or shape (rectangular, square, etc.). In some embodiments, as shown, the posts 12, 14, and 16 can be hollow. Figure 1C As can be seen, at the rear end B, the top plate 10 and bottom plate 50 are also coupled together by a spine plate 60. The movable assembly 20 and spine plate 60 will be described later. While the posts 12, 14, and 16 are illustrated as having a cylindrical shape (in the XY plane), this is merely exemplary. In general, these posts 12, 14, and 16 can have any suitable configuration or shape (rectangular, square, etc.). In some embodiments, as shown, the posts 12, 14, and 16 can be hollow. Figure 1AAs can be best observed, posts 12 and 14 located at the front end A of the test holder 100 can have a smaller diameter (or width in embodiments where these posts are not cylindrical) than post 16 located at the back end B thereof. Locating the smaller diameter posts 12 and 14 at the front end A can provide a larger gap between these posts 12, 14 and thus enable easier loading of a sample (syringe, beaker, etc.) into the test holder 100. Although not necessary, in some embodiments, the posts 12 and 14 can have substantially the same diameter or width, although in other embodiments, the posts 12 and 14 can have different diameters and / or widths (each smaller than the corresponding diameter and / or width of post 16). The posts 12, 14, and 16 can generally be formed of any suitable material and can be formed in any suitable manner. In some embodiments, these posts 12, 14, and 16 can be formed of a metallic material, such as stainless steel, aluminum, etc., although it is contemplated that in other embodiments, the posts 12, 14, and / or 16 can be formed of a polymeric material or a combination of metal and polymer. In some embodiments, the posts 12, 14, and / or 16 can be formed by 3D printing. It is contemplated that the test holder 100 can be coupled to a universal testing machine (UTM), such as a UTM produced by Instron or ZwickRoell. For example, the base plate 50 can be coupled to the UTM via holes 50C (see Figure 1A ) configured to receive bolts of the UTM. The bolts can be any suitable size, such as M6 bolts or M10 bolts.

[0018] The posts 12, 14, and 16 can be fixedly coupled to the top plate 10 and the base plate 50 and can be slidably coupled to the middle plate 30. In other words, the top plate 10 and the base plate 50 are fixed relative to the posts 12, 14, 16, and the middle plate 30 can slide relative to the posts 12, 14, 16 in a vertical direction on the posts 12, 14, 16. The posts 12, 14, and 16 can be fixedly coupled to the top plate 10 and the base plate 50 in any manner. In some embodiments, these posts 12, 14, and 16 can be press fit on the top plate 10 and the base plate 50. Additionally or alternatively, in some embodiments, threaded rods or other types of fasteners can be used to couple the posts 12, 14, 16 to the top plate 10 and the base plate 50 (see, e.g., Figure 1D 、 2A and 2B). In some embodiments, bearings 18A, 18B, and 18C (e.g., linear motion bearings) can be coupled to the middle plate 30 to enable the middle plate 30 to slide relatively easily on the posts 12, 14, and 16. These bearings 18A, 18B, and 18C can also center the posts 12, 14, and 16 on the respective through holes or cavities in the middle plate 30 through which these posts 12, 14, and 16 extend. In some embodiments, as shown (see, e.g., Figures 1A to 1CThe bearings 18A-18C are coupled to the intermediate plate 30 using fasteners (e.g., four fasteners) that are arranged substantially symmetrically about the respective posts 12, 14, 16. Since suitable bearings 18A, 18B, and 18C that can be used to slidably couple the intermediate plate 30 to the posts 12, 14, and 16 are known to those skilled in the art, they are not described in detail herein. The bearings 18A, 18B, and 18C are shown in the illustrated embodiment as being fastened to the underside of the intermediate plate 30 (i.e., closer to the bottom plate 50 than to the top plate 10). This configuration can help create additional space for samples on the intermediate plate 30. However, it is contemplated that one or more of the bearings 18A, 18B, and / or 18C can be located on the top of the intermediate plate 30 (i.e., closer to the top plate 10 than to the bottom plate 50).

[0019] The top plate 10 can have a first lateral end face 10A at the front end A and a second lateral end face 10B at the rear end B. The first lateral end face 10A can be substantially parallel to the second lateral end face 10B. Similarly, the intermediate plate 30 can have a first lateral end face 30A at the front end A and a second lateral end face 30B at the rear end B. The first lateral end face 30A can be substantially parallel to the second lateral end face 30B. It is also contemplated that the lateral end faces 10A, 10B, 30A, and / or 30B can be substantially parallel to each other. In some embodiments, the posts 12 and 14 can be positioned closer to the first lateral end faces 10A and 30A than to the second lateral end faces 10B and 30B. In some embodiments, each of the post 16, the ridge plate 60, and the moving assembly 20 can be positioned closer to the second lateral end faces 10B and 30B than to the first lateral end faces 10A and 30A.

[0020] The top plate 10 and the intermediate plate 30 can each have a central cavity or recess 15, 32 that extends from the front end A to the rear end B of the test fixture 100. In particular, the cavity 15 can extend from an opening 10C in the first lateral end face 10A of the top plate 10 toward the second lateral end face 10B. Similarly, the cavity 32 can extend from an opening 30C in the first lateral end face 30A of the intermediate plate 30 toward the second lateral end face 30B. In some embodiments, it is contemplated that the openings 10C and 30C face in the same direction (i.e., toward the front end A of the test fixture 100). However, this is not required, as it is contemplated that the opening 10C can extend through the second lateral end face 10B, such that the cavity 15 extends from the second lateral end face 10B toward the center of the top plate 10. In alternative embodiments, the opening 15C can face the rear end B. Although not required, in some embodiments, as shown, the central cavity 15 can be substantially centrally located in the width of the top plate 10, and the central cavity 32 can be substantially centrally located in the width of the intermediate plate 30. The central cavity 15 on the top plate 10 can extend from the front end A to a rear (closed) end 15A (see FIG. 2). Similarly, the central cavity 32 on the intermediate plate 30 can extend from the front end A to a rear (closed) end 32A (see FIG. 2). Figure 2A), and the central cavity 32 on the middle plate 30 can extend from the front end A to the rear (closed) end 32A (see Figure 1A , 2A ). The central cavity 15 on the top plate 10 and the central cavity 32 on the middle plate 30 can be arranged on their respective plates such that they are vertically aligned. That is, when viewed from the top of the test holder 100, the central cavity 15 can be directly above the central cavity 32 (see Figure 2A , 2B ). In other words, one or more longitudinal axes (substantially parallel to the Z-axis) can intersect each of the cavities 15 and 32. The intersecting longitudinal axes can be substantially parallel to the longitudinal axes of the posts 12, 14, and 16, the spine plate 60, and the moving assembly 20. As will be described later, a cradle 80 (e.g., a U-shaped cradle that holds different types of samples) can be coupled to the central cavity 15 on the top plate 10. When the test holder 100 is used to hold a sample during testing, the sample can be located in (or inserted into) the test holder 100 via one or both of the central cavities 15, 32. The central cavities 15 and 32 can have any shape and size. In general, the shape and size of the central cavities 15 and 32 can depend on the size and configuration of the sample intended to be used with the test holder 100. In some embodiments, one or both of the central cavities 15 and 32 can have a generally rectangular or U-shape. Typically, the size of the central cavities 15 and 32 can be such that these cavities 15, 32 do not extend all the way from the front end A to the rear end B of the test holder 100. That is, as can be seen in Figs. 2A and 2B, the top plate 10 and the middle plate 30 can include a band of material that extends from the rear end 15A, 32A of their respective central cavities 15, 32 to the rear end B of the test holder 100. Moreover, the rear (closed) ends 15A and 32A can be positioned closer to the second lateral end faces 10B and 30B than to the first lateral end faces 10A and 30A. Figure 1A , 1C , 2A and 2B, the top plate 10 and the middle plate 30 can include a band of material that extends from the rear end 15A, 32A of their respective central cavities 15, 32 to the rear end B of the test holder 100. Moreover, the rear (closed) ends 15A and 32A can be positioned closer to the second lateral end faces 10B and 30B than to the first lateral end faces 10A and 30A.

[0021] The spine plate 60 that couples the top plate 10 and the bottom plate 50 can extend through the middle plate 30 via a vertically extending cavity 36 (or through-hole) located between the rear end 34 of the central cavity 32 and the rear end B of the test holder 100 (see Figure 1C ). The cavity 36 can be sized such that the spine plate 60 extends through the middle plate 30 without interfering with the vertical movement of the middle plate 30 (described later). For example, in some embodiments, the cavity 36 can be sized such that the spine plate 60 can extend through the middle plate 30 without physically contacting it. The spine plate 60 can be fixedly coupled to the top plate 10 and the bottom plate 50, e.g., using fasteners. For example, Figure 1CAs can be seen, fasteners 52A, 52B can extend through cavities in the spine plate to couple the spine plate 60 to the base plate 50. Similar fasteners (not shown) can extend through cavities 16A and 16B in the top plate 10 to couple the spine plate 60 to the top plate 10. These fasteners for coupling the spine plate 60 to the top plate 10 can extend through the cavities 16A, 16B, through the back end 14 of the central cavity 15 into the central cavity 15 (of the top plate 10). The portions of these fasteners that extend into the central cavity 15 can be used to attach a stand 80 (or another suitable stand, replacement part, etc.) to the central cavity 15. Although the spine plate 60 is shown as a rectangular shaped part, this is merely exemplary. In general, the spine plate 60 can have any suitable shape and size (e.g., width, thickness, etc.) that provides sufficient rigidity to the test holder 100. In some embodiments, the spine plate 60 can be designed in size and include material (or otherwise configured) to provide sufficient stability to the test holder 100 to resist twisting and / or bending forces that can occur during testing (e.g., twisting and bending forces generated by a sample supported by the test holder 100 on the test holder 100). The spine plate 60 can be formed in any suitable manner. In some embodiments, the spine plate 60 can be a 3D printed part that is configured to provide increased rigidity in the lengthwise direction. More specifically, the spine plate 60 can generally be a polymer 3D printed part. In some embodiments, one or more sheets of reinforcing material can be embedded within the spine plate 60. For example, the spine plate 60 can be printed from a plastic composite material having one or more reinforcing materials therein, such as metal strands. In another example, the spine plate 60 can include printed sheets of metal or fiberglass within an otherwise 3D printed polymer plate. Including 3D printed reinforcing materials can help ensure that the spine plate 60 has sufficient rigidity to resist twisting and / or bending forces that can occur during testing, while also being quickly and easily manufactured as needed. As noted above, the spine plate 60 can have plates integrated therein to help achieve sufficient torque on bolts that extend through the entire holder 100. The upper through-bolts that make the holder 100 a single continuous unit can cause slack between the components in some embodiments, which can affect the rigidity of the holder 100. Thus, in at least some embodiments, it is desirable that the single continuous unit, i.e., the holder 100, be rigid to obtain accurate test results.

[0022] Repeatability testing was used to demonstrate the effectiveness of reinforcing the spine 60. During repeatability testing, a load was applied to the top plate 10. The load was approximately 200 N, and the deflection of the top plate 10 was measured over time during the application of the load. This approximate load was significantly higher than the loads applied during various medical injector tests for which the test fixture 100 was used, including, for example: (1) break loose glide force tests (e.g., from about 1 N below to about 20 N), (2) override force tests of the locking mechanism (e.g., from about 50 N to about 100 N, (3) injection force tests of auto-injectors (e.g., from about 50 N to 100 N), and (4) cap removal force tests (e.g., from about 50 N to about 100 N). For example, during break loose glide force tests, the displacement per unit of force can measure about 15 mm to about 20 mm of displacement. These tests typically last for about 3 seconds to about 5 seconds, or up to about 10 seconds. However, these durations are merely exemplary, and other durations are also contemplated. At this approximate load, and as described above after reinforcing the spine 60 with a metal plate, the measured displacement of the top plate 10 under the approximate 200 N load was approximately 0.225 to 0.242 mm (data samples are shown in the “Displacement - With Support” column of Table 1 below), with a standard deviation of 0.0049 mm. In another test, in a fixture without any spine 60, the measured displacement of the top plate 10 under the same approximate 200 N load ranged from 1.164 nm to 1.193 mm (data samples are shown in the “Displacement - Without Support” column of Table 1), with a standard deviation of 0.0068 mm. The repeatability testing described herein was performed in April 2019. During the repeatability testing, an ElectroPuls Instron machine was used to apply a 200 N load in the upward direction, and then cyclically applied to the top plate 10 in the downward direction. The duration of each cycle (including the upward and downward applied forces) was 1 second, and the test time for each fixture was 72 hours (259,200 cycles or 259,200 seconds). The displacement of the top plate 10 was measured after every five cycles (seconds). Table 1 reflects the data samples collected during the repeatability testing. The testing of the supported and unsupported fixtures was performed on different days. The difference in displacement between the equivalent cycles of the two tests ranged from 0.927 mm to 0.964 mm, with a standard deviation of 0.0349 mm. It was observed that most of the (relatively small) deviations in the displacement data collected during the repeatability testing could be attributed to temperature variations in the testing area. In another test, not shown in Table 1, in which the spine 60 was made of only plastic and without any reinforcing material, the displacement of the top plate 10 was approximately 0.35 to 0.40 mm.

[0023]

[0024]

[0025] Table 1: Sampling of Repeated Test Data for Supported and Unsupported Test Fixtures

[0026] Therefore, by adding the ridge plate 60, the displacement exhibited by the top plate 10 under a load (200 N) is reduced compared to a test fixture without the ridge plate 60. Furthermore, by adding a printed metal support to the ridge plate 60, the displacement exhibited by the top plate 10 under a load (200 N) is reduced compared to a test fixture with a ridge plate 60 consisting only of printed plastic. In some embodiments, the test fixture 100 may be configured such that when a load of 200 N is applied to the top plate 10 over a 72-hour period, the top plate 10 exhibits a displacement not exceeding approximately 0.40 mm, approximately 0.35 mm, approximately 0.25 mm, approximately 0.24 mm, or approximately 0.23 mm. The top plate 10 can be physically coupled to the bottom plate 50, so that when a load of 200 N is applied to the top plate 10 during a 72-hour period, the top plate 10 can exhibit a displacement of no more than about 0.40 mm, about 0.35 mm, about 0.25 mm, about 0.24 mm or about 0.23 mm.

[0027] Furthermore, according to this disclosure, the spine plate 60 may or may not be reinforced. In some embodiments, reinforcement may not be necessary when the spine plate 60 is configured to withstand loads expected to be applied during operation (e.g., testing of an injection medical device). In other words, reinforcement may not be necessary when the spine plate 60 is able to support the top plate 10 such that the top plate 10 exhibits acceptable low deformation or no deformation under conceivable loads during testing of an injection medical device. For example, it is believed that when components of the retainer 100 including the spine plate 60 are manufactured on the same day in a 3D printer from plastic (and without reinforcement), the performance of such a spine plate 60 (i.e., no deflection of the top plate 10) will be comparable to that of a spine plate 60 having reinforcement material.

[0028] The intermediate plate 30 may also include a recessed cavity or track 38 extending laterally (or substantially perpendicularly) in the XY plane to the central cavity 32 (see [link]). Figure 1A The track 38 may include a first portion 38A extending on one side of the central cavity 32 and a second portion 38B extending on the opposite side of the central cavity 32. The first portion 38A may be collinear with the second portion 38B. The track 38 may be a slotted cavity configured to slidably support one or more of the components. The component 40 is slidably supported on each portion 38A, 38B of the track 38. Figure 1AOnly one finger assembly 40 is shown (on the first portion 38A). Each finger assembly 40 can be configured to slide on the track 38 toward and away from the central cavity 32. Although not required, in some embodiments, each finger assembly 40 can be a spring-loaded component (or assembly of components) biased toward the central cavity 32. That is, the finger assemblies 40 on both portions 38A and 38B of the track 38 can be biased toward each other.

[0029] Each finger assembly 40 can include a base 42 or carriage configured to slide on the track 38 toward and away from the central cavity 32. Although not required, in some embodiments (not shown), a thumb screw (or another mechanism such as a slot) can be provided to lock the base 42 in a desired position on the track 38. A thumb screw 48 can be used to couple a finger member or finger 46 to the base 42 of each finger assembly 40. As shown, the finger 46 can be an elongated component extending from an end proximate the thumb screw 48 to an opposite end toward the central cavity 32. The finger 46 is coupled to the base 42 such that the length of the finger 46 is at an angle to the base 42. That is, the finger 46 can be at an angle relative to the base 42. The angle formed by the finger 46 and the base 42 can be changed using the thumb screw 48. For example, loosening the thumb screw 48 (e.g., by turning the thumb screw 48) allows the finger 46 to rotate about the thumb screw 48 and change the angle between the finger 46 and the base 42. Figure 1A

[0030] In spring-loaded embodiments of the finger assembly 40, a spring 45 can bias the finger 46 in an upward direction (i.e., toward the top plate 10 and away from the bottom plate 50). The spring 45 can be coupled to a pin 46a disposed on the underside of the finger 46. In particular, the spring 45 can be housed in a groove (not shown) on or adjacent to the pin 46a. The spring 45 can also be coupled to a screw or other fastener 46b. The fastener 46b can couple the base 42 to a protrusion housed by a slot or groove of the track 38. Thus, when a downward force is applied to the finger 46 (by a sample or test instrument), the spring 45 can compress to allow the finger 46 to rotate downward. Upon release of the downward force, the spring 45 can expand to its resting state and the finger 46 can return to its original and / or resting position. In some embodiments, the presence of the spring 45 can enable testing of a sample without any sample clamping. For example, in some embodiments, a sample can be held only by tension.

[0031] ​The ends of the fingers 46 positioned toward the central cavity 32 can be configured to contact and support a sample in the test fixture 100 during testing. For example, in embodiments where a syringe is supported on the test fixture 100 for testing, the body of the syringe can be supported vertically by the fingers 46 of the finger assembly 40 on either side of the central cavity 32, such that the syringe extends through the central cavity 32 toward the floor 50. In this configuration, the load arm of the UTM can be lowered through the central cavity 15 in the top plate 10 into the test fixture 100 and exert the desired type of force (tensile, compression, etc.) at the desired location of the syringe. The ability to shift the finger assembly 40 on the track 38 (e.g., in the X-direction in the Figure 1A embodiments, the ends of the fingers 46 positioned toward the central cavity 32 can include an inwardly facing recess 46c that can be used to support the flange of a syringe or injector being tested (e.g., the finger flange of a syringe). It should be noted that while a particular configuration of the finger assembly 40 with fingers 46 is shown in the drawings, this is merely exemplary. In general, the finger assembly 40 and fingers 46 can have any configuration.

[0032] As previously mentioned, the middle plate 30 of the test fixture 100 can be slidably coupled to the columns 12, 14, 16. The movement assembly 20 can be used to slide the middle plate 30 on the columns 12, 14, 16 and move the middle plate 30 in the vertical direction (i.e., toward or away from the top plate 10 or the floor 50). Referring to Figure 1C , the movement assembly 20 includes a screw 22 supported on a collar, such as an open clamp 56 (e.g., a McMaster open clamp) disposed on the floor 50. As shown in Figure 1C , in some embodiments, the open clamp 56 can be disposed in or embedded in a correspondingly shaped cavity formed on a dial 54 on the floor 50. As shown in Figure 1C , in some embodiments, the dial 54 is a tire-like protrusion on the floor 50 that includes a central cavity that supports the open clamp 56.

[0033] As will be appreciated by those skilled in the art, rotating the dial 54 about the longitudinal (Z) axis of the assembly 20 allows the screw 22 (e.g., worm) to rotate on the base plate 50. The screw 22 can be self-braking and have a helical geometry such that pushing on the intermediate plate 30 does not result in a vertical translation of the intermediate plate 30. Rather, the movement assembly 20 can be configured to enable the intermediate plate 30 to be vertically moved by only turning the dial 54. For example, the intermediate plate 30 can include a threaded standoff fastener (e.g., nut) 24 that receives the threads of the screw 22. The top end of the screw 52 includes a bearing 26 attached thereto. In some embodiments, the bearing 26 can have a semi-spherical hole into which the top end of the screw 52 fits. In some embodiments, the bearing 26 is not attached to the top plate 10. In some embodiments, the top of the bearing 26 can contact the back surface of the top plate 10 such that the bearing 26 can slide (in the XY plane) on the top plate 10 to minimize the effect of rotating the screw assembly 20 out of alignment on moving the assembly 20 on the test fixture 100. As the dial 54 is turned (or rotated), the screw 22 (and the bearing 26) rotates relative to the top plate 10 and the base plate 50. The screw 22 extends through the intermediate plate 30 via the bearing 24 attached thereto. As will be appreciated by those skilled in the art, the bearing 24 translates the rotational movement of the screw 22 to a linear movement of the intermediate plate 30 to which it is attached. Although not seen in the figures, in some embodiments, the intermediate plate 30 can also include a bearing (e.g., brass bearing, bronze bearing, etc.) positioned in a cavity through which the screw 22 extends. Turning the dial 54 causes the ball screw 22 to rotate about the top plate 10 and the base plate 50 and causes the intermediate plate 30 to translate up and down in the vertical direction (Z direction). Rotation of the dial 54 in one direction causes the intermediate plate 30 to move in one direction (e.g., toward the top plate 10 or toward the base plate 50), and rotation of the dial in the opposite direction causes the intermediate plate 30 to move in the opposite direction. The ability to move the intermediate plate 30 up or down enables different types and sizes of samples to be supported in the test fixture 100.

[0034] It is also contemplated that the movement assembly 20 can be any suitable linear movement component configured to translate the intermediate plate 30 relative to the top plate 10 and the base plate 50 along the Y axis. For example, the movement assembly 20 can include a pulley system, etc.

[0035] As explained previously, the central cavity 15 of the top plate 10 can support a holder 80 (see Figure 1A 、 1B , 2A, 2B). An exemplary holder 80 that can be supported in the top plate 10 is shown in Figure 3 . As Figure 1A and 1BAs can be best observed, the sidewall of the central cavity 15 can include a slot 82A (e.g., a rectangular recess, etc.). In some embodiments, the slot 82A extends along the length of the central cavity 15 from the front end A of the test holder 100 to the back end 14 of the central cavity 15 (i.e., along the Y-axis, see Figure 2A ). The slot 82A on the sidewall of the central cavity 15 is configured to slidably receive a correspondingly shaped protrusion 82B on the side of the bracket 80. The bracket 80 can be attached to the central cavity 15 by engaging the protrusion 82B with the slot 82A of the central cavity 15 and sliding the bracket 80 into the central cavity 15 such that the front surface of the bracket 80 is flush with the front surface of the top plate (see Figure 1A 、 1B ). Fasteners for coupling the spine plate 60 to the top plate 10 can then be inserted into the cavities 16A, 16B (see Figure 1C ). These fasteners can extend through the top plate 10 into threaded holes 86A, 86B on the back surface of the bracket 80 (see Figure 3 ) to attach the spine plate 60 and the bracket 80 to the top plate 10.

[0036] The bracket 80 can also be used to support a sample in the test holder 100 for testing. The inner end of the bracket 80 can include a feature 84 configured to engage with the sample and support the sample on the bracket 80. It should be noted that Figure 3 the bracket 80 and feature 84 shown are merely exemplary. In general, the type of bracket used and the type of feature disposed on the bracket will depend on the type of sample to be supported. In some embodiments, a first bracket (e.g., the bracket 80) can be used to support one type of sample during a test. After the test, the bracket can be removed and another bracket attached to the central cavity 15 to support a different sample for another test. The ability to quickly swap out brackets configured to support different types of samples increases the flexibility of the test holder.

[0037] In some embodiments, the feature disposed on the bracket 80 can be configured to support another bracket. For example, with reference to the bracket 80 of Figure 3 、 3A and 3B, in some embodiments, the feature 84 on the inner surface of the bracket 80 can be configured to engage and support another bracket 80A (e.g., an inner bracket 80A that fits within the bracket 80 and is configured to support some test samples), the bracket 80A being configured to support a sample. In such embodiments, the bracket attached to the top plate 10 (e.g., the bracket 80) can not be replaced to support a different configuration of test samples. Instead, the inner bracket 80A supported by the bracket 80 attached to the top plate can be replaced by another inner bracket configured to support a new test sample. The ability to quickly replace brackets and / or inner brackets to support different samples configurations enables the test holder 100 to be used to support many different configurations of test samples.

[0038] The inner shelf 80A can include a circular opening and other suitable features configured to support a test sample, such as a syringe. In some embodiments, the inner shelf 80A can be configured to accommodate one or more syringe adapters or discs used in testing by the UTM. The syringe adapters or discs can be commercially available or custom made, and can be individually designed to support different samples, syringes, containers, etc. For example, the adapters or discs can be configured to accommodate or support various syringe diameters, shapes, configurations, etc.

[0039] In some embodiments, the shelf (e.g., shelf 80) in the top plate 10 and the finger assembly 40 in the middle plate 30 can be configured to collectively support a sample for testing. For example, a syringe extending through (e.g., vertically through) the cavities 12 and 32 of (the top plate 10 and the middle plate 30) can be supported by both the shelf 80 of the top plate 10 and the fingers 46 of the finger assembly 40 of the middle plate 30. The ability to change the gap between the top plate 10 and the middle plate 30 by vertically moving the middle plate 30 using the dial 54 enables different configurations and sizes of samples to be easily supported on the test fixture 100 without changing the fixture. The ability to easily reconfigure the test fixture 100 to test different test samples increases efficiency while saving time and money.

[0040] Figure 5A and 5B An example replacement part that can be installed in the middle plate 30 is shown. For example, Figure 5A A sample holding arm 500 is shown that can be used to support a sample collection container on a platform 502. For example, the holding arm 500 can be used to support a "bulk" primary container (i.e., a syringe) that is tested under tension, or the holding arm 500 can be used to hold a waste collection cup when weighing of the sample is not required. These uses are not limiting, and it is contemplated that the holding arm 500 can also be used for other testing applications. The sample collection container can collect liquid that is ejected from a syringe or test device during testing. Similarly, Figure 5B A holder 510 that can be used to support or hold a centrifuge tube or the like is shown. Figure 5A and 5B The replacement part or adapter shown can be used in certain tests that do not use the finger assembly 40. The holding arm 500 and / or the holder 510 can be coupled to the middle plate 30 by one or more fasteners (e.g., bolts) that extend through holes in the holding arm 500 and / or the holder 510 and through holes in the middle plate 30.

[0041] Figures 5C to 5E An example replacement part that can be used with the top plate 10 to test, for example, an ISO vial or other similar container is shown. Figure 5CA rack 80 is shown for use with an inner rack 80B (instead of the inner rack 80A described above). The inner rack 80B can be used to hold vials for puncture testing. The inner rack 80B can include a mating flange 80C configured to rest on a top surface of the rack 80 in order to couple the inner rack 80B to the rack 80. The inner rack 80B can also include a bottom surface 80D that is offset (in a different plane than the mating flange 80C) from the mating flange 80C, although it is contemplated that in at least some embodiments the mating flange 80C and the bottom surface 80D can be coplanar. A sidewall 80E can be disposed between the mating flange 80C and the bottom surface 80D, and in some embodiments can be substantially perpendicular to both the mating flange 80C and the bottom surface 80D. The sidewall 80E can include partially cylindrical portions that connect substantially parallel portions of the sidewall 80E on opposite ends. The partially cylindrical portions of the sidewall 80E can have a radius that is about or slightly greater than the radius of a sample container or vial to be tested. Further, the distance between the substantially parallel portions of the sidewall 80E can be about or slightly greater than the radius of a sample container or vial to be tested. During testing, a bottom portion of the sample container or vial can be supported by the bottom surface 80D and the sidewall 80E.

[0042] Figure 5D A rack 80F is shown that can be inserted into the top plate 10, for example, using protrusions 82B, in substantially similar fashion to the racks 80 described herein. The rack 80F can include a top surface 80G that is positioned above and offset from the protrusions 82B, although they can be coplanar in some embodiments. The rack 80F can include one or more posts 80H that extend upward and away from the top surface 80G. In the illustrated embodiment, the rack 80F includes three posts 80H, although the number is not limited and the rack 80F can include more or fewer posts 80H. Each post 80H can include a lumen extending therethrough, and can also include one or more mating features, such as threads, rails, etc., to accommodate complementary features of a fastener, such as a bolt or screw. The rack 80F can include a bottom surface 80I that is positioned below and offset from the top surface 80G. A sidewall 80J can be disposed between and substantially perpendicular to the top surface 80G and the bottom surface 80I. Similar to the sidewall 80E described above, the sidewall 80J can include partially cylindrical portions that connect substantially parallel portions of the sidewall 80J on opposite ends.

[0043] Figure 5EA retaining plate 80K is shown that can be coupled to and used in conjunction with the cradle 80F to perform cap removal force testing on a sample container or vial (where the testing force can be rotated from one side of the sample container or vial). The retaining plate 80K can include one or more openings 80L extending therethrough, each opening 80L configured to align with a corresponding post 80H from the cradle 80F. In the illustrated embodiment, the retaining plate 80K includes three openings 80L, but it is not limited as such and the retaining plate 80K can include additional or fewer openings 80L. The retaining plate 80K can include a recess 80M that at least partially corresponds in shape to the bottom surface 80I of the cradle 80F. Further, a sidewall 80N can surround the recess 80M, and portions of the sidewall 80N can correspond in shape and geometry to the sidewall 80J of the cradle 80F. Portions of the sidewalls 80J and 80N can be vertically aligned when the retaining plate 80K is coupled to the cradle 80F.

[0044] The retaining plate 80K can be coupled to the cradle 80F by aligning the openings 80L with the openings of the internal cavities of the posts 80H. Fasteners (e.g., screws or bolts) can be inserted through the respective openings 80L / posts 80H to secure the retaining plate 80K to the cradle 80F. The respective shapes of the retaining plate 80K and the cradle 80F can allow both the retaining plate 80K and the cradle 80F to support different portions of the same sample container or vial. For example, the bottom surface 80I and the sidewall 80J can support the bottom of the sample container or vial, while the sidewall 80N can support an upper or middle portion of the same sample container or vial.

[0045] Similar to other replacement parts described herein Figures 5C to 5E The components of the test holder 100 can be designed and manufactured in significantly less time than existing components used to perform the same tests. For example, Figures 5C to 5E The components of the test holder 100 can be designed in less than three hours and printed in less than ten hours. As described above, these replacement parts can be used for testing of ISO vials, while the test holder 100 can help keep the sample and replacement parts concentric and help position the sample container or vial at the minimum test height of the system. The test holder 100 and its various replacement parts allow for quick modification of the test holder 100 to accommodate testing of different components (e.g., pre-filled syringes and ISO vials), while existing test preparation requires significantly more hardware and setup time / cost.

[0046] Embodiments of the present disclosure can be used in any suitable test configuration. For example, embodiments of the present disclosure can be used to collect force versus time date in syringe or auto-injector testing. The disclosed devices can be used in syringe / plunger force testing, such as unthreading separation force testing (determining the force required to initially depress the plunger) or maintenance / slip force testing (determining the force required to keep the plunger moving). The disclosed devices can also be used in (1) needle cap or other pull-off testing (e.g., forced removal of needle / safety cap), (2) activation force and displacement testing, (3) testing to determine the force required to move a needle guard, (4) needle insertion and withdrawal testing, (5) Luer cone breakage tests. The disclosed devices can also be used with blister pack testing, tablet crush testing, or other testing by the UTM that requires a new support structure to be developed or purchased. Thus, the disclosed devices can be used for any tensile or compression testing on a device, sample container, or vial, such as a medical device, that requires the device under test to be secured or braced in a particular orientation. The disclosed devices can be used to secure a variety of test structures having a volume ranging from about 0.5 mL to about 5 mL or more. Smaller and larger volume containers are also contemplated, such as containers having a volume of about 0.5 mL or less, including, for example, containers of about 0.4 mL or less, about 0.3 mL or less, about 0.2 mL or less, or about 0.1 mL or less. In addition, containers having a volume greater than about 5 mL can be tested, including, for example, containers having a volume of about 10 mL or more, about 20 mL or more, about 30 mL or more, etc. The containers under test can be cylindrical, conical, rectangular, quadrangular pyramidal, irregular, and / or can have any other suitable shape or combination of shapes.

[0047] Figure 6An exemplary method 600 is shown. The method 600 can begin at step 602, where the test fixture 100 can be coupled or otherwise secured to a testing machine, such as the universal testing machine described above. The method 600 can then proceed to step 604, where a user selects an appropriate insert or replacement part and secures it to the test fixture 100 for a first desired test. For example, the user can select one or more of the cradle 80, the inner cradle 80A, the finger assembly 40, the holding arm 500, the holder 510, and / or any other suitable replacement part needed for the first test. The method 600 can also include step 606, where the test fixture 100 and the selected replacement part can be further configured. This can include, for example, moving the intermediate plate 30 in the vertical direction, adjusting the tension of the finger assembly 40, or any other desired setup task depending on the needs of the first test. Step 606 can occur before, during, or after step 604. The method 600 can then proceed to step 608, where the first test is performed. In some cases, the user can wish to perform another test using the test fixture 100, and thus the method 600 can proceed to step 610, where the user can select a new insert or replacement part to be used during the second or subsequent test. The method 600 can proceed from step 610 to steps 612 and 614, which can be substantially similar to steps 604 and 606, respectively, modified as necessary due to the differences between the first test and the second or subsequent test. Similar to steps 604 and 606, step 612 can occur before, during, or after step 610. After step 614, the method 600 can be complete, or can return to step 610 to perform additional subsequent tests.

[0048] A second or subsequent test can be the same type of test as the first test (e.g., a slide test), but can be performed on a different sample or device (e.g., a different syringe). The second or subsequent test can also be a different type of test on the same sample or device used in the first test, or a different type of test on a different sample / device than used in the first test. However, regardless of the type of test or sample contemplated for use in the second or subsequent test, the same test fixture 100 can be used, and can only require a new configuration of parts and / or inserts. For example, a new cradle 80 and / or a new inner cradle 80A can be used in the test. In some examples, only a new inner cradle 80A can be used, or the inner cradle 80A can be removed. In other examples, the retaining arms 500 and / or retainers 510 can be used on the intermediate plate 30 in the second test in place of the use of the finger flanges 40, or vice versa. In some embodiments, the method step 610 can occur without decoupling the test fixture 100 from the universal test machine. However, this is not a limitation, and in fact in some embodiments, it is contemplated that the test fixture 100 can be used with different universal test machines, or the same universal test machine, when some decoupling / re-coupling between tests is required.

[0049] Compared to existing testing solutions, embodiments of the present disclosure enable testing with minimal overhead. For example, the cost of existing test setups ranges from $100 to over $1000. Furthermore, the expenditure of capital costs and employee labor costs (often significantly higher than capital costs) must be spent on new setups to perform new tests. Additionally, there is a loss of productivity during the design, manufacture, and / or shipping of new test equipment in the case of existing setups. However, the modular test fixtures of the present disclosure can help alleviate these issues. For example, after investing in an initial module, such as a 3D printer (ranging from about $300 to about $250,000 or more), new tests can be performed at significantly reduced costs, especially considering that many users can have already invested in a suitable 3D printer otherwise. Some 3D printers can be configured to print inserts or replacement parts into a final, ready-to-use form, while others can print intermediate components that must be further modified. For example, for certain printers, additional supports (e.g., steel rods) can be needed, or intermediate parts can need to be further milled or machined. For example, new inserts or replacement parts can include a material cost of about $10 to $100. Since only the insert / replacement part needs to be designed, rather than the entire module, design time (and thus employee labor costs) is reduced. Still further, inserts / replacement parts require less design and manufacturing expertise to create, and thus, individuals who can lack significant experience in creating test instruments (e.g., chemists, chemical engineers, biomedical engineers, bioscientists, etc.) can still be able to create suitable inserts / replacement parts. Furthermore, in the case of seeking additional help from engineering / design / manufacturing experts, such help can be limited compared to when a completely new test setup is needed. Still further, many of the inserts / replacement parts of the present disclosure can be printed on-site (e.g., by a 3D printer), and since a customized insert / replacement part can be ready for use within a few hours / days, there is a reduced loss of productivity compared to the longer time frame needed to build and ship a new test setup. Furthermore, it is contemplated that after a new insert or replacement part is designed, 3D printing of such insert or replacement part can be outsourced to a third-party 3D printer, with a cost range to the user of about $400 to about $700.

[0050] In embodiments of the present disclosure, it is contemplated that the need for a new replacement part can be recognized at a first point in time, and the new replacement part can be designed and manufactured (e.g., via 3D printing) as a ready-to-use assembly, and then used in a tensile or compressive test within about 12 hours or less, measured from the first point in time. Other time periods are also contemplated, particularly given the complexity of certain assemblies. In other embodiments, the new replacement part can be ready-to-use, and the replacement part is actually used in a tensile or compressive test within about 18 hours or less, or about 24 hours or less, measured from the first point in time. Further, in at least some embodiments of the present disclosure, the new replacement part can be manufactured via 3D printing only (i.e., sending a print instruction to a 3D printer and printing a complete, ready-to-use component without any additional milling, machining, etc.).

[0051] As used herein, an insert or replacement part can be any component required to support and / or orient a test sample or container for compression and / or tensile testing using a modular test fixture. The component can directly or indirectly contact the test sample or container, and can include any structure such as, but not limited to, a bracket, a platform, a support surface, a post, a flange, a fastener, etc.

[0052] While the principles of the present disclosure are described herein with reference to test fixtures that can be used in conjunction with another device (e.g., a UTM), it should be understood that the present disclosure is not so limited. Rather, the systems described herein can be used in any application of a machine set. Moreover, those of ordinary skill in the art, as well as others to which this description is directed, will appreciate that additional modifications, applications, embodiments, and equivalents of the embodiments described herein fall within the scope of the embodiments described herein. Thus, the present disclosure should not be considered limited by the foregoing description. For example, while certain features have been described in conjunction with various embodiments, it should be understood that any feature described in conjunction with any of the embodiments disclosed herein can be used in conjunction with any other embodiment disclosed herein.

Claims

1. A testing apparatus, comprising: First platform; The second platform includes a first cavity having a first opening extending through a first lateral end face of the second platform, wherein the first cavity extends from the first opening toward the center of the second platform, and wherein the second platform further includes a first track and a second track, each of the first track and the second track being configured to accommodate a spring-loaded retainer. A third platform, fixed relative to the first platform, includes a second cavity having a second opening extending through a first lateral end face of the third platform, wherein the second cavity extends from the second opening toward the center of the third platform. and A spine plate, which is fixed to the first platform and the third platform; The second platform is located between the first platform and the third platform, and is movable relative to both the first platform and the third platform. The second platform includes a third opening through which the ridge plate extends, wherein the ridge plate abuts the closed ends of the first cavity and the second cavity. The testing apparatus further includes a moving component configured to move the second platform relative to the first platform and the third platform.

2. The testing apparatus of claim 1, wherein the moving component has a first longitudinal axis, the moving component is coupled to each of the first platform, the second platform and the third platform, wherein rotation of the moving component about the first longitudinal axis causes the second platform to move relative to the first platform and the third platform.

3. The testing apparatus according to claim 2, wherein, At least a portion of each of the first cavity and the second cavity is disposed along a second longitudinal axis parallel to the first longitudinal axis of the movable assembly.

4. The testing apparatus according to claim 1, wherein the first opening and the second opening face the same direction.

5. The testing apparatus according to claim 4, wherein the same direction is towards the front of the testing apparatus.

6. The testing apparatus according to claim 1, wherein the first platform and the second platform are substantially parallel to each other.

7. The testing apparatus according to claim 6, wherein the first platform and the third platform are substantially parallel to each other.

8. The testing apparatus according to claim 1, wherein the moving component comprises a worm gear.

9. The testing apparatus of claim 8, wherein the second platform includes a threaded fastener for receiving the worm.

10. The testing apparatus of claim 2, wherein the first platform includes an actuation component configured to receive an end portion of the movable component, wherein the actuation component includes a dial configured to rotate the movable component about the first longitudinal axis.

11. The testing apparatus of claim 10, wherein the actuation component includes a collar surrounded by the dial, wherein the moving component extends through the collar.

12. The testing apparatus according to claim 1, wherein the testing apparatus is used for compression testing and / or tensile testing.

13. The testing apparatus according to claim 1, wherein the first track and the second track are collinear.

14. The testing apparatus of claim 1, further comprising a first spring-loaded retainer and a second spring-loaded retainer, the first spring-loaded retainer being configured to be received by the first rail, and the second spring-loaded retainer being configured to be received by the second rail.

15. The testing apparatus of claim 14, wherein the first spring-loaded retainer includes a first finger and a first spring, wherein the first finger is biased toward the third platform by the first spring, and the second spring-loaded retainer includes a second finger and a second spring, wherein the second finger is biased toward the third platform by the second spring.

16. The testing apparatus of claim 1, wherein the ridge plate comprises a polymer and one or more metal sheets disposed within the polymer.

17. The testing apparatus of claim 1, further comprising a U-shaped support detachably accommodated by the second cavity.

18. The testing apparatus of claim 17, wherein the second cavity comprises one or more slots, and the U-shaped support comprises one or more protrusions configured to be received by the one or more slots.

19. The testing apparatus according to claim 1, wherein, The second platform includes a second lateral end face, which is substantially parallel to the first lateral end face of the second platform; and The testing device includes a first support member and a second support member, which are coupled to the first platform and the second platform, wherein the first support member and the second support member are located closer to the first lateral end face of the second platform than to the second lateral end face of the second platform.

20. The testing apparatus of claim 19, further comprising a third support member coupled to the first platform and the second platform, wherein the diameter of the third support member is greater than that of each of the first support member and the second support member, and the third support member is located closer to the second lateral end face of the second platform than to the first lateral end face of the second platform.

21. The testing apparatus of claim 19, wherein the moving component is located closer to the second lateral end face of the second platform than to the first lateral end face of the second platform.

22. A testing apparatus, comprising: First platform; The second platform includes: A cavity having an opening extending through a first lateral end face of the second platform; and First and second orbits; and The third platform is fixed relative to the first platform; The second platform is positioned between the first platform and the third platform, and is movable relative to both the first platform and the third platform. The testing apparatus further includes: A mobile component configured to move the second platform relative to the first platform and the third platform; A first spring-loaded retainer, configured to be received by the first rail, the first spring-loaded retainer including a first finger and a first spring, wherein the first finger is biased toward the third platform by the first spring; and A second spring-loaded retainer, configured to be received by the second rail, includes a second finger and a second spring, wherein the second finger is biased toward the third platform by the second spring. The testing apparatus further includes a spine plate fixed to the first platform and the third platform, the second platform including a third opening through which the spine plate extends, wherein the spine plate is adjacent to the closed end of the cavity.

23. A testing apparatus, comprising: First platform; The second platform includes a cavity having an opening extending through a first lateral end face of the second platform. The second platform also includes a first track and a second track, each of which is configured to accommodate a spring-loaded retainer. The third platform is fixed relative to the first platform; The second platform It is positioned between the first platform and the third platform. It can move relative to the first platform and the third platform. The testing apparatus further includes: A mobile component configured to move the second platform relative to the first platform and the third platform; and A ridge plate, the ridge plate being fixed to the first platform and the third platform, the second platform including an opening through which the ridge plate extends, wherein the ridge plate comprises a polymer and one or more metal sheets disposed within the polymer.

24. A testing apparatus, comprising: First platform; The second platform includes a first cavity having a first opening extending through a first lateral end face of the second platform, wherein the first cavity extends from the first opening toward the center of the second platform, and the second platform also includes a first track and a second track, each of the first track and the second track being configured to accommodate a spring-loaded retainer. and A third platform is fixed relative to the first platform. The third platform includes a second cavity having a second opening that extends through a first lateral end face of the third platform, wherein the second cavity extends from the second opening toward the center of the third platform. The second platform Located between the first platform and the third platform, and It can move relative to the first platform and the third platform; The testing apparatus further includes a moving assembly configured to move the second platform relative to the first and third platforms; and a spine plate fixed to the first and third platforms, the second platform including a third opening through which the spine plate extends, wherein the spine plate abuts the closed ends of the first and second cavities. When a load of approximately 200 N is applied to the third platform, the displacement of the third platform does not exceed approximately 0.40 mm.

25. The testing apparatus of claim 24, wherein when the load is applied, the displacement of the third platform does not exceed about 0.23 mm.

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