Support fixture and test specimen holder used with the support fixture

Abstract

A support fixture 10 for use with a testing machine 1 that applies a tensile load. The support fixture 10 includes a frame 12 and a pair of spaced supports 14A, 14B joined to the frame 12 to provide an alignment axis 16. Each support 14A, 14B releasably holds a specimen holder on the alignment axis 16 in a fixed spatial relationship with the ends of the specimen holder attachable to the testing machine 1 facing in opposite directions. A method is also provided for using the support fixture 10 to attach a specimen 15 to the specimen holder at a location remote from the testing machine 1, and then using the support fixture 10 to maintain the fixed, special relationship while the specimen holder is attached to the testing machine 1.

Description

Background Art

[0001] The following discussion is provided only for the purpose of general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.

[0002] Specimen holders or grips are known in materials testing technology and are often used to hold specimens in a materials testing system. The holder includes opposing jaws or wedges that hold the specimen therebetween. Although such specimen holders have been used for a long time, it has been confirmed that such holders can be used to test relatively large specimens, but it is not known to use them for very small specimens.

[0003] Typical specimens used have a geometric shape with a minimum length of 25 mm or more and a cross-section of several millimeters by several millimeters. These specimens can be used in various specimen holders. The holder is installed in a force reaction structure or testing machine that applies a longitudinal force along the long axis of the specimen. The holder typically has a way to roughly but repeatably align the specimen within the holder, and the holders can be easily aligned with each other to ensure low bending strain as required by ASTM test procedures. The holder also requires the user to install the specimen within the holder while the testing machine actively maintains position and load.

[0004] In the field of additively manufactured components, investigation of the material properties of the deposition process has been required. As a result, specimen cross-sectional shapes have been obtained with a thickness of less than 1 mm, a width of less than 1 mm, and a total length of less than 10 mm. These specimen sizes do not fit current specimen holders, and there is no way to insert the specimen into the holder in a repeatable manner. Also, due to the very small size of the specimen, additional time is required to install the specimen, thereby raising concerns that the user will be exposed to the operating machine for a longer period of time.

Summary of the Invention

[0005] This summary and abstract in this specification is provided in a simplified form to introduce selected concepts that are further described below in the detailed description. This summary and abstract is not intended to identify any important or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that address any or all of the defects described in the background art.

[0006] Generally, a support fixture used with a testing machine that applies a tensile load includes a frame and a pair of spaced-apart supports joined to the frame to provide an alignment axis. Each support releasably holds a specimen holder on the alignment axis in a fixed spatial relationship, with the ends of the specimen holder, which are mountable to the testing machine, facing in opposite directions. The support fixture can be used with any type of specimen holder, including, but not limited to, specimen holders disclosed herein, which have distinct and additional embodiments of the present invention.

[0007] In one embodiment, the support fixture further includes a specimen support joined to a frame between a pair of spaced supports. The specimen support conveniently holds the specimen on an alignment axis so that a specimen holder can be secured to each end of the specimen. The ends of the specimen support may have recesses for receiving the specimen. Preferably, the specimen support comprises a first portion joined to a frame and a second portion having ends. The second portion is adjustablely fixed to the first portion so as to adjust the position of the ends perpendicular to the alignment axis, thereby enabling the precise positioning of specimens of different widths on the alignment axis. The second portion may be linearly adjustable relative to the first portion, such as by expanding or contracting relative to the first portion.

[0008] Preferably, the pair of supports includes a first support and a second support, and at least one of the supports, preferably both supports, is adjustable on a frame to adjust the position of the support(s)(s) on the alignment axis in the axial direction. In a preferred embodiment, each support includes a recess or protrusion spaced away from the alignment axis, complementary to the protrusion or recess provided on an associated specimen holder that can be fixed to the support. The complementary engagement of the protrusion and recess orients the specimen holder around the alignment axis so that it can be properly mounted on a specimen.

[0009] In one embodiment, each support provides a mounting opening for receiving a portion of a specimen holder. Preferably, each support includes a removable portion that can be fixed to the end forming the mounting opening to allow for convenient mounting of each specimen holder. The end and removable portion of each support include a surface that is complementary to the specimen holder and engageable with the specimen holder.

[0010] Another aspect of the present invention also discloses a method of using a support fixture to mount a test specimen in a test specimen holder at a position away from the testing machine, and then using the support fixture to maintain a fixed special relationship while the test specimen holder is mounted in the testing machine.

[0011] In one embodiment, a method for loading a specimen into a tensile testing machine having a first specimen holder and a second specimen holder includes providing a support fixture away from the testing machine; mounting the first specimen holder and the second specimen holder to the support fixture such that the heads configured to hold the end of the specimen face each other and the ends of the specimen holders, which can be fixed to the testing machine, face in opposite directions, wherein the specimen holders are aligned with each other and positioned on a common alignment axis; fixing the heads of the first specimen holder and the second specimen holder to the first and second ends of the specimen, respectively; and mounting the first specimen holder and the second specimen holder to the tensile testing machine, wherein the support fixture holds the first specimen holder and the second specimen holder in a spatial relationship fixed to each other on the alignment axis.

[0012] In a further embodiment, the fixture includes a specimen support, and the method further includes mounting the specimen to the specimen support so as to be aligned with an alignment axis. Preferably, mounting the specimen to the specimen support so as to be aligned with the alignment axis is done before fixing the heads of the first and second specimen holders to the specimen.

[0013] The fixture may include a first support and a second support connected to a frame, and mounting the first and second specimen holders to the support fixture includes mounting the first specimen holder to the first support and mounting the second specimen holder to the second support. Mounting the first and second specimen holders to a tensile testing machine can be done after mounting the first and second specimen holders to the support fixture and / or after fixing the heads of the first and second specimen holders to the specimens.

[0014] If desired, mounting the first and second specimen holders to a support fixture to properly align the specimen holders relative to each other to correctly hold the specimen may include fixing the rotational positions of the first and second specimen holders around their respective alignment axes. Preferably, fixing the heads of the first and second specimen holders to the first and second ends of the specimen, respectively, includes applying a preloaded clamping force to the ends of the specimen.

[0015] Another aspect of the present invention is a test specimen comprising a head body having a first inclined body surface and a second inclined body surface facing each other. A first wedge and a second wedge are arranged within the head body, the first wedge having a first inclined wedge surface that slides in contact with the first inclined body surface, and the second wedge having a second inclined wedge surface that slides in contact with the second inclined body surface. A support shaft has a first end that can be connected to a part of the testing machine and a second end that supports the first and second wedges. A drive is supported by the support shaft and is positioned between the second and first ends. A spring is connected to the head body at the first end and to the drive at the second end.

[0016] Preferably, the drive is configured to pull the second end of the spring away from the head body. The drive may include a first part that is movable relative to the second part, the first part being connected to the second end of the spring, and the second part engaging with or firmly joining to a portion of the support shaft. The first part can move axially relative to the support shaft with or without rotation around the support shaft.

[0017] The drive may include a driven portion that contacts and is movable relative to a first portion and a second portion. The driven portion is movable toward and away from the longitudinal axis of the support shaft. Preferably, the drive includes an actuator supported by the first portion that contacts the driven portion. In one embodiment, the actuator includes a drive screw that screws into the first portion.

[0018] The engagement surfaces of the driven portion and the second portion may include at least one inclined surface on at least one of the driven portion and / or the second portion. Preferably, the engagement surfaces of the driven portion and the second portion are inclined surfaces.

[0019] The drive may include walls forming a chamber around a support shaft, the driven element being disposed within the chamber, and the drive may include end caps joined to the ends of the walls.

[0020] In one embodiment, the spring comprises a plurality of longitudinal spring elements arranged around a support shaft, preferably as a body at least partially cylindrical around the support shaft, wherein the spring elements are integral with a body formed from a single, integral structure having longitudinal slots.

[0021] Preferably, at least one of the mount or head body is provided with either an opening on its outer surface that extends inward laterally with respect to the longitudinal axis of the support shaft, or a pin that extends laterally away from the outer surface with respect to the longitudinal axis, so as to enable the specimen holder to be attached to the support fixture.

[0022] Another embodiment of the test piece holder includes a head body having a first inclined body surface and a second inclined body surface facing each other. A first wedge and a second wedge are disposed within the head body, the first wedge having a first inclined wedge surface that slidably contacts the first inclined body surface, and the second wedge having a second inclined wedge surface that slidably contacts the second inclined body surface. The mount is joined to the head body at a first end and has a bore. A support shaft is disposed within the bore and has a first end that supports the first wedge and the second wedge. A spring biases the support shaft toward the head body.

[0023] In one embodiment, the bore includes an inner flange, a first end of the spring that engages the support shaft, and a second end that engages the inner flange. The spring can include a compression spring.

[0024] In one embodiment, an adjustment portion is provided to adjust the force biasing the support shaft toward the head body. The adjustment portion can include an actuator joined to the support shaft. For example, the actuator can include a screw that is threaded into the mount.

[0025] Preferably, the handle is joined to the support shaft and includes a portion that extends in a direction opposite to the longitudinal axis of the support shaft.

[0026] Preferably, at least one of the mount or the head body includes an opening that opens to the outer surface and extends inwardly in a direction transverse to the longitudinal axis of the support shaft, or a pin that extends outwardly from the outer surface in a direction transverse to the longitudinal axis, so as to enable the test piece holder to be attached to the support jig.

Brief Description of the Drawings

[0027] [Figure 1] It is a perspective view of a testing machine. [Figure 2] It is a perspective view of a support jig. [Figure 3]It is a cross-sectional view of the support jig along line 3-3 in FIG. 2. [Figure 4] It is a front elevation view of the test piece holder. [Figure 5] It is a right side elevation view of the test piece holder in FIG. 4. [Figure 6] It is a top view of the test piece holder in FIG. 4. [Figure 7] It is a cross-sectional view of the test piece holder along line 7-7 in FIG. 6. [Figure 8] It is a cross-sectional view of the test piece holder along line 8-8 in FIG. 6. [Figure 9] It is an exploded view of the test piece holder in FIG. 4. [Figure 10] It is a view showing the mount of the test piece holder in FIG. 4. [Figure 11] It is a view showing the handle of the test piece holder in FIG. 4. [Figure 12] It is an exploded view of a part of the test piece holder in FIG. 4. [Figure 13] It is a perspective view of the second embodiment of the test piece holder. [Figure 14] It is a cross-sectional view of the test piece holder along line 14-14 in FIG. 13. [Figure 15] It is a cross-sectional view of the test piece holder along line 15-15 in FIG. 13. [Figure 16] It is an exploded view of the test piece holder in FIG. 13. [Figure 17] It is an exploded view of a part of the test piece holder in FIG. 13. [Figure 18] It is an exploded view of a part of the test piece holder in FIG. 13. [Figure 19] It is an exploded view of a part of the test piece holder in FIG. 13. [Figure 20] It is a perspective view of the test piece holder attached to the support jig. [Figure 21] It is a perspective view of the test piece holder attached to the support jig. [Figure 22] It is a perspective view of the test piece holder attached to the support jig. [Figure 23]This is an elevation view of the specimen holder and support fixture installed inside the testing machine. [Modes for carrying out the invention]

[0028] A material testing system 1 for applying a force load to a test specimen is shown in Figure 1. System 1 typically includes an upper test specimen holder and an identical lower test specimen holder, both types of which are illustrated and described below. The test specimen holder holds the test specimen along the longitudinal axis 2. In the illustrated embodiment, the lower test specimen holder is connected to an actuator 3, through which a force load is applied to the test specimen and reacts as a whole against a reaction structure shown 4.

[0029] In the illustrated exemplary embodiment, although other configurations are known and can be used in conjunction with the embodiments of the present invention described below, the material testing system 1 includes a frame 5 having a base 6. A pair of support members 7 extend upward from the base 6 and are joined to each other by a crossbeam 8 that provides a stable support surface. A pair of columns 8A extend upward from the crossbeam 8 to a crosshead 8B that is movable on the columns 8A. A load cell 9 can be connected to the crosshead 8B with an upper specimen holder, or to a rod of an actuator 3 with a lower specimen holder, as shown. As is known in the art, the load cell 9 provides a signal indicating an tensile or compressive force applied to the specimen. The crosshead 8 and columns 8A provide a reaction structure. A hydraulic lift 8C moves the crosshead 8 to a selective fixed position.

[0030] In general, among other embodiments, the specimen holders 100, 200 (Figures 4 to 19) are described as capable of through-zero fatigue loads, tensile loads, and compressive loads on small and ultra-small specimens, both with flat and rounded geometric shapes. The specimen holders 100, 200 function in conjunction with specimen insertion or support fixtures 10 (Figures 2, 3, and 20 to 23), which are intended to allow specimen insertion to be performed on a workbench or table away from the testing machine 1. The support fixtures firmly and precisely hold the specimen holders 100, 200 so that bending strain on the specimens inherent in the installation process is limited and repeatable. The support fixtures 10 provide a method for introducing clamping force to the specimen holders 100, 200 without applying incorrect loads to the specimens. The support fixture 10 allows the user to verify the installation accuracy and enables the fixture / test specimen holder subsystem to be installed within the testing machine 1 without incorrect loads being applied to the test specimen until the testing machine 1 is under control and managing the load and displacement.

[0031] One aspect of the present disclosure is a support fixture 10 (Figures 2, 3 and 20-23) used to mount a test specimen 15 to a test specimen holder or grip 100, 200 so that it is precisely positioned within the test specimen holder or grip 100, 200 without any undesirable loads that could damage or break the test specimen 15, and to align the test specimen 15 with the axis of the test specimen holder 100, 200 so that the required tests can be performed in the testing machine 1. The support fixture 10 enables the accurate and repeatable loading of the test specimen 15 into the test specimen holder 100, 200.

[0032] With the test specimen 15 loaded into the test specimen holders 100, 200 and the test specimen holders 100, 200 fixed to the fixture 10, the complete assembly including the test specimen holders 100, 200, the support fixture 10 and the test specimen 15, as shown in Figure 22 (Figure 23), can be transferred to the testing machine 1, and force and / or displacement can be applied to the test specimen 15 using the testing machine 1 described above. Such testing machines are known in the art as tensile or elongation testing machines (used to apply monotonic or unidirectional loads) or elongation / compression testing machines (used in fatigue tests where alternating elongation and compression loads may be applied). If desired, a rotary actuator (not shown) may be part of the testing machine 1 with or without a linear actuator 3. Since all loads between the specimen holders 100 and 200 are transmitted through the support fixture 10 and not through the specimen 15, the support fixture 10 allows the specimen holders 100 and 200 and the specimen 15 mounted between them to be loaded into the testing machine 1 without causing damage to the specimen 15. Once the specimen holders 100 and 200 are fixed to the testing machine 1, the fixture 10 can be removed from the specimen holders 100 and 200 and the test can be started.

[0033] Referring to Figures 2 and 3, the support fixture 10 includes a frame 12 having a base 13. A pair of spaced-apart supports 14A and 14B are joined to the base 13. Each support 14A and 14B releasably holds a specimen holder on an alignment axis 16 (Figure 20). A specimen support 20 is joined to the frame 12 between the pair of spaced-apart supports 14A and 14B. The specimen support 20 has an end 22 configured to hold a specimen 15 on the alignment axis 16.

[0034] The specimen support 20 includes a first portion 20 joined to a base 13 or frame 12, and a second portion 20B having an end 22. The second portion 20B is adjustablely fixed to the first portion 20A so as to adjust the position of the end 22 perpendicular to the alignment axis 16. Preferably, the second portion 20B is linearly adjustable relative to the first portion 20A. In the illustrated embodiment, the second portion 20B expands and contracts relative to the first portion 20A. The end 22 may include a recess of size and shape for holding the specimen 15 on the alignment axis 16. If it is desired to assist in holding the specimen 15 to the end 22, a retaining device such as a clip, clamp, tape, or strap may be provided on the end 22. Fasteners 24 can be used to fix the specimen support 20 to the frame 12, and fasteners 26 such as set screws can be used to fix the second portion 20B to a desired position relative to the first portion 20A.

[0035] The pair of supports 14A and 14B are preferably adjustable on the frame 12 axially or parallel to the alignment axis 16 to adjust the position of supports 14A and 14B relative to the test specimen support 20. Preferably, each of supports 14A and 14B is adjustable and positionable on the frame 12 and mounted on linear bearing supports 26A and 26B, respectively. In a preferred embodiment, each linear bearing support 26A and 26B is mounted on a straight rail 28 without backlash (vertical backlash in the illustrated embodiment) and is only capable of linear movement along the rail 28.

[0036] In the illustrated embodiment, the frame 12 includes an optional alignment guide 30. Each of the support members 14A and 14B is supported by a rail 28, but the guide 30 defines the orientation of the alignment axis 16, which remains substantially parallel to the guide 30. Preferably, each of the support members 14A and 14B and the specimen support 20 include bores 34A, 34B, and 34C, respectively, to receive the guide 30. The guide 30 is held in a stationary position relative to the base 13 by a standoff 36, which in the illustrated embodiment also has a bore 38 to receive the end of the guide 30, and fasteners such as set screws 40 secure the guide 30 to the standoff 36.

[0037] Supports 14A and 14B move linearly relative to the rail 28, guided by the guide 30 to maintain proper alignment. Once the specimen holders 100 and 200 are attached to their respective supports 14A and 14B, and the specimens 15 are attached to each of the holders 100 and 200, supports 14A and 14B are securely fastened to the guide 30 by corresponding fasteners 33. In the illustrated embodiment, each fastener includes a set screw that fixes the position of each support 14A and 14B on the guide 30. In Figure 2, the set screw 33 fastens support 14A to the guide 30, while support 14B includes a similar set screw on the back of support 14B in Figure 2. Similarly, the specimen support 20 is fastened to the guide 30 using fasteners such as set screw 35.

[0038] It should be noted that the use of guide 30 is not mandatory. Specifically, guide 30 is not necessary if the supports 14A, 14B and the test specimen support 20 can be fixed to the rail 28 so that their alignment is properly aligned with respect to each other along the alignment axis 16.

[0039] This specification discloses two different specimen holders 100, 200, including other embodiments of the present invention. Specimen holder 100 is generally used for tensile testing, but can also be used for fatigue testing with lighter loads. Specimen 200 is particularly well suited for fatigue testing. Each specimen holder 100, 200 can be used with a support fixture 10. Each specimen holder 100, 200 is releasably fixed to its respective support 14A, 14B. Generally, each of the specimen holders 100, 200 described below comprises a base or mount 102, 202 and a head body 104, 204 fixed to the mount 102, 202 (Figures 4, 14). The mounts 102, 202 typically include a cylindrical member that can be inserted into and fixed therein a corresponding recess provided in the testing machine 1, such as a grip. The head body 104, 204 includes a wedge used to hold the end of the specimen 15 during testing.

[0040] In the illustrated embodiment, the supports 14A and 14B are releasably fixed to the respective mounts 102 and 202 of the specimen holders 100 and 200. However, it should be noted that, if desired, the supports 14A and 14B can be configured to be releasably fixed to the specimen and the respective head bodies 104 and 204 of the holders 100 and 200.

[0041] Each support 14A, 14B includes a mounting opening configured to receive a portion of the specimen holders 100, 200. In the illustrated embodiment, the mounting opening is formed from portions 40A, 40B that are removably fixed to the ends 38A, 38B of each support 14A, 14B, respectively. The surfaces of the removable portions 40A, 40B and the ends 38A, 38B together engage with the surfaces of the specimen holders 100, 200. Fasteners 42 secure each removable portion 40A, 40B to the corresponding ends 38A, 38B.

[0042] For specimens having substantially flat ends to which specimen holders 100 and 200 are attached, the specimen holders 100 and 200 need to be properly oriented around the alignment axis 16 so as to coincide with and properly engage with the end of the specimen 15.

[0043] Typically, since the specimens have ends that lie on the same plane, each of the specimen holders 100, 200 should be oriented in the same position relative to each other so as to orient each of the specimen holders 100, 200 to their appropriate positions. The supports 14A, 14B and the holders 100, 200 include a protrusion-opening connection between the supports 14A, 14B and the specimen holders 100, 200, which aligns and holds the specimen holders 100, 200 to their appropriate rotational positions around the alignment axis 16. In the illustrated embodiment, the protrusion includes a pin 50 (Figure 3). The pin 50 can be securely fixed within the supports 14A, 14B, for example, within the removable portions 40A, 40B, and / or within the ends 38A, 38B of each support 14A, 14B as shown. With the support members 14A and 14B having a protrusion or pin 50, the specimen holders 100 and 200 include corresponding openings 101 and 201 sized to receive the pin 50. In an alternative embodiment, the protrusion, such as a pin, can be arranged on the specimen holders 100 and 200, in which case the openings are provided on the support members 14A and 14B.

[0044] Figures 4 to 12 show the specimen holder 100. Generally, the specimen holder 100 includes a mount or base 102 and a head body 104 fixed to the end of the mount 102. At the end opposite to the head body 104, the mount 102 is inserted into a corresponding recess provided in the testing machine 1, and the testing machine 1 may have another larger specimen holder. A stop-collar 106 limits the distance the mount 102 is inserted into the testing machine 1.

[0045] As described above, the specimen holder 100 is preferably placed within a support fixture 10 in which the rotational position is fixed accurately and repeatedly. The convex-opening described above can be used. In the illustrated embodiment, the convex portion according to this specification, including the pin 50, is fixed to the respective supports 14A and 14B, and the opening 101 is located within the mount 102.

[0046] In general, the specimen holder 100 includes movable wedges 120 that are supported by and slide on a support plate 118. Each wedge 120 has a specimen engagement surface that engages with the specimen 15, facing the other wedge. In the illustrated embodiment, the wedges 120 are flat for use with flat specimens, but this should not be considered limiting in that the wedges 120 may be configured to hold specimens of other shapes, such as specimens having cylindrical ends, for example, the wedges 120 include notches. The wedges 120 together engage with the specimen 15 from both sides. Each wedge 120 includes an inclined back surface 122. The inclined surface 124 of the head body 104 engages with the inclined back surface 122 of each wedge 120, and the relative displacement between the head body 104 and the wedges 120 drives or biases the wedges 120 toward each other. The use of such wedges in the head body is known and will not be further described. However, although two wedges 120 are shown in the exemplary embodiment, one wedge or three or more wedges may be used, and it should be noted that each wedge commonly engages with the inclined surface 122 on the head body 104.

[0047] The springs 130 are attached to the wedges 120 and have a spring bias that drives or biases the wedges 120 apart from each other, creating space and allowing the end of the test piece 15 to be easily inserted between the wedges 120. In the illustrated embodiment, each of the springs 130 includes a torsion spring with one end that can be inserted into a recess or opening 132 (Figure 12) provided in the wedge 120, the other end being firmly held by the head body 104, and in this specification, the opposite end being received in a recess or opening 134 (Figure 8).

[0048] A support plate 118 for the wedge 120 is attached to a support rod or shaft 140 that extends downward away from the head body 104. The support plate 118 includes upright sides or edges that generally face each other but maintain the orientation of the wedges 120 so as to allow the wedges 120 on the support plate 118 to move toward and away from each other. The specimen holder 100 includes a biasing spring 142. The biasing spring 142 biases the wedges 120 toward each other by biasing the support shaft 140 upward toward the head body 104, and engages with the end of the specimen located between the wedges 120. The biasing spring 142 is, as specified herein, a coil spring received in a bore 144 provided in the mount 102. The support shaft 140 has an extended portion 146 having a width that allows it to be inserted into the coil provided in the biasing spring 142. A flange 148 is provided inside the support shaft 140, which engages with the uppermost coil of the biasing spring 142.

[0049] A handle 150 fixed to the support shaft 140 allows the wedge 120 to be opened, due to a spring force provided to a spring 130 that biases the wedge 120 apart from each other, by allowing the support shaft 140 to be pulled away from the head body 104 against a biasing spring 142. In the illustrated embodiment, the handle 150 has a portion 152 that extends in the opposite direction through a slot 154 provided in the mount 102. The handle portion 152 is fixed to the support shaft 140, which includes a bore 156 sized to receive the handle shaft 158. Generally, the above design allows the handle 150 to be pulled downward away from the head body 104, thereby biasing the wedge 120 apart from each other so that the end of the test piece can be inserted between the wedges 120. When the handle 150 is released, a clamping force is generated and applied to the end of the test piece 15.

[0050] In the illustrated embodiment, a preload clamping force adjustment unit 160 (Figures 6 and 7) is provided to apply a force that further biases the wedges 120 toward each other so as to apply a preload clamping force to the end of the test piece 15. The adjustment unit 160 has an actuator 162 that biases the wedges 120 toward each other by biasing the support shaft 140 toward the head body 104. The adjustment unit 160 includes a drive screw that abuts against the end of the shaft 140 and is screw-connected to a threaded bore in the mount 102.

[0051] The test specimen 15 is secured to the test specimen holder 100 in two steps. First, the handle 150 is pulled down against the biasing spring 142, thereby separating the wedges 120 and allowing the test specimen 15 to be positioned between them. When the handle is released, the wedges 120 come into contact with the test specimen 15 and hold the test specimen 15 by the force provided by the biasing spring 142. Next, the actuator 160 is actuated by rotation, which in this specification is by a drive screw, further biasing the shaft 146 toward the head 104, thereby driving the wedges 120 toward each other and toward the test specimen 15.

[0052] The second specimen holder 200 is shown in Figures 13 to 19. The specimen holder 200 includes a mount 202, a head body 204, and a wedge 220. The wedge 220 and head body 204 operate similarly to the wedge 120 and head body 104, with the inclined back surface of the wedge 220 sliding on the inclined surface of the head body 204, causing the wedge 220 to move laterally toward each other.

[0053] Mount 202 is connected to the support shaft 240 at a first end 240A using fasteners 203, and the second end 240B supports the first and second wedges 220. A drive 210, supported by the support shaft, is positioned between the first end 240A and the second end 240B. A spring 212 is connected to the drive 210, for example, by screw connection at the first end to the head body 204 and by screw connection at the second end to the cylindrical first portion 214.

[0054] The drive 210 is configured to pull the spring 212 so as to displace the head 204 axially downward relative to the shaft 240. As the head 204 moves downward, the wedges 220 are biased toward each other. The specimen 15 is also secured to the specimen holder 200 in two steps. First, with the screw connection between the spring 212 and the first part 214 being minimal, the wedges 220 are far enough apart from each other so that the specimen can be inserted between them, allowing the head 204 to be displaced upward away from the end of the shaft 240. The spring 223 biases the wedge 220 toward the inclined surface of the head 204 so that the wedge 220 forms a space that allows the specimen 15 to be inserted. In this embodiment, each of the springs 223 is elongated, with the first end firmly attached to the support shaft 240 and the second end firmly attached to the wedge 220.

[0055] Next, the first part 214 is rotated around the shaft 240 to strengthen the threaded connection between the first part 214 and the spring 212. This pulls the spring 212 and the head downward, and as a result the wedge 220 is biased toward each other and toward the test piece 15, where the spring 212 provides the spring force.

[0056] To further enhance the clamping force of the wedge 220, the drive 210 includes an actuator or displacement mechanism that further displaces the first portion 214 axially downward. The actuator mechanism includes a driven portion 228 that contacts and is movable relative to the first portion 214 and the second portion 216. In the illustrated embodiment, the driven portion 228 is movable laterally as specified, toward and away from the longitudinal axis of the support shaft 240. An actuator 230 supported by the first portion 214 engages in contact with the driven portion 228. The actuator 230 moves toward and away from the longitudinal axis, and is preferably positioned laterally with respect to the longitudinal axis. In the illustrated embodiment, the actuator 230 may include a drive screw that screws into the first portion 214. The engaging surfaces of the driven portion 228 and the second portion 216 include an inclined surface on at least one of the driven portion 228 and / or the second portion 216, and in a preferred embodiment, each of the driven portion 228 and the second portion 216 includes an inclined surface that engages with each other. The wall 234 can form a chamber 236 around the support shaft 240, and the driven portion 228 and the second portion 216 are disposed within the chamber 236. An end cap 238 is joined to the end of the wall 234 to trap the driven portion 228 and the second portion 216 within the chamber 236 and to maintain the driven portion 228 in contact with the second portion 216. The second portion 216 can be securely fixed to the support shaft 240, and in one embodiment, it is formed integrally with the support shaft 240 and formed from a single, one-piece structure. In an alternative embodiment, as shown in the figure, the second portion 216 may be separable from the support shaft 240 and may include a disc-shaped element having an opening 216A through which a portion 240A of the support shaft 240 passes. In such a configuration, the second portion 216 engages with an annular flange 240B provided on the support shaft 240 to provide a reaction structure.

[0057] If the second portion 216 comprises a disk element, the driven portion 228 may also be formed as a disk having an opening 228A through which a portion 240A of the support shaft 240 passes. However, the opening 228A comprises a slot having a longitudinal axis that traverses the longitudinal axis of the support shaft 240. The slotted opening 228A allows the driven portion 228 to move laterally with respect to the longitudinal axis of the support shaft 240. In the illustrated embodiment, the actuator 230 comprises two separate actuators 230A, 230B, the first actuator 230A used to drive the driven portion in the direction indicated by arrow 250A, and the second actuator 230B used to drive the driven portion 228 in the opposite direction by arrow 250B. One or both of the actuators 230A, 230B may comprise a threaded element that screws into the first portion 214.

[0058] To increase the clamping force of the wedge 220 on the test specimen 15, the actuator 230 is operated to displace the driven element 228. In the illustrated embodiment, the inclined surfaces of the second portion 216 and the driven element 228 cause the actuator 230B to move in the direction of arrow 250B, further displacing the cylindrical first portion 214 downward relative to the shaft 240, thereby increasing the extension of the spring 212 and pulling the head 204 downward. When the test specimen is removed, the actuator 230B is moved in the direction of arrow 250A, and then the actuator 230A is also operated to drive the driven element 228 in the direction of arrow 250A, allowing the cylindrical portion 214 to move axially upward. The cylindrical portion 214 can then be rotated to sufficiently minimize the threaded connection between the spring and the cylindrical portion 214, as a result the wedge 220 separates and the test specimen 15 can be removed.

[0059] Referring to Figure 17, the spring 212 may comprise a plurality of longitudinal spring elements arranged around the support shaft 240. In the illustrated embodiment, the spring 212 comprises a cylindrical body having longitudinal slots 212A, and the spring elements are portions 212B of the cylindrical body located between the consecutive longitudinal slots 212A. In one embodiment, the spring 212 is screwed into the head body 204 at a first end 212C and into the drive 210 at a second end 212D.

[0060] Similar to the specimen holder 100 described above, the opening 201 is provided to receive the pin 50 of the support fixture 10. The pin 50 can be positioned between two consecutive longitudinal spring elements, for example, by being routed through one of the slots 212A provided within the cylindrical body.

[0061] A method of using specimen holders, such as but not limited to holders 100, 200, etc., together with a support fixture 10 preferably includes positioning the support fixture 10 on a work surface away from the testing machine 1, fixing the selected specimen holder to the supports 14A, 14B, preferably using a convex-opening connection between the specimen holder and the supports 14A, 14B, and positioning the specimen 15 within the specimen holder by opening the corresponding wedges of the specimen holders 100, 200, as is customary herein, so that the end of the specimen 15 is positioned between the wedges. After the specimen 15 is attached to each of the specimen holders and the supports 14A, 14B are fixed to the fixture 10 so that all or substantially all force loads between the specimen holders 100, 200 are transmitted through the fixture 10, thereby protecting the specimen 15 from being subjected to such forces, the specimen holders 100, 200 can be attached to the testing machine 1, and once fixed, the support fixture 10 can be removed.

[0062] In one embodiment, the method further includes allowing the supports 14A and 14B to move freely on the frame 12 of the support fixture 10 while the end of the test piece is being loaded, and then fixing the supports 14A and 14B in a fixed position relative to the frame of the support fixture 10 or to an optional guide 30.

[0063] Referring to Figure 20 and the specimen holder 100, setting up the specimen 15 is as simple as releasing the wedge 120 using the handle 150, as shown in Figure 21, and placing the specimen 15 into one of the holders 100 while releasing the wedge 120 on the specimen 15. The specimen holder 100 is moved toward the other end of the specimen 15 and secured to the specimen 15 in the same manner to achieve the setup shown in Figure 22. The actuators 160 of each holder 100 are then activated to increase the clamping force applied to the specimen 15 and to provide a defined load path from the wedge 120 to the mount 102. The specimen 15 is now set in the holder 100. The set screws of the supports 14A and 14B can be operated to secure the supports 14A and 14B to the rail 28 and / or guide 30 (if provided). The alignment of the test specimen within the specimen holder can be verified by various means, namely mechanical measurement, optical measurement using light / shadow, laser, and camera. Other verification methods, such as photoelastic paint, can also be used.

[0064] Referring to Figure 23, the fixture 10, including the specimen holder (e.g., 100) and the specimen 15, is transferred to the testing machine 1. In Figure 23, optional intermediate holders 280 and 282 are used. In the illustrated embodiment, the upper specimen holder is attached to the load cell 9, the load cell 9 is attached to the intermediate holder 280, and the intermediate holder 280 is attached to the actuator if it is located within the crosshead 8, or directly to the crosshead 8. Similarly, the lower specimen holder is attached to the lower intermediate holder 282 attached to the actuator 3, or to the base of the testing machine via a load cell if provided.

[0065] In the exemplary testing machine 1 shown in Figure 23, one mount of the specimen holder 100 is installed in the testing machine 1, for example, by direct connection to a load cell 9 via a clevis pin. After one end is installed, the testing machine 1 can be operated to position the other end of the specimen holder 100, for example, having a grip 282, to grip the other end. After installation, preferably, the testing machine 1 is placed in a force-controlled state and operated so that the force applied between the specimen holders 100 is zero. With the applied force at zero, the fixture 10 can be removed, and at this point the testing machine 1 is ready to perform testing on the specimen. Re-verification of the specimen alignment within the specimen holder can be re-verified by various means, namely mechanical measurement, optical measurement by light / shadow, laser, and camera. Other verification means such as photoelastic paint can also be used.

[0066] While the subject matter has been described in terms relating to specific environments, structural features, and / or methodological actions, it should be understood that the subject matter as defined in the attached claims is not limited to the aforementioned environments, specific features, or actions, as has been determined by the courts. Rather, the aforementioned environments, specific features, and actions are disclosed as exemplary forms that implement the claims. Some aspects of the present invention are described below. [Aspect 1] In a support fixture used with a testing machine that applies tensile load, Frame and, It comprises a pair of spaced-apart support bodies joined to the frame to provide an alignment axis, Each support is a support jig that releasably holds a specimen holder on the alignment axis in a fixed spatial relationship, with the ends of the specimen holder, which can be attached to the testing machine, facing in opposite directions. [Aspect 2] The support fixture according to embodiment 1, further comprising a test specimen support joined to the frame between the pair of spaced-apart supports, wherein the test specimen support has an end configured to hold the test specimen on the alignment axis. [Aspect 3] The support fixture according to embodiment 2, comprising a first portion joined to the frame and a second portion having the end, wherein the second portion is adjustablely fixed to the first portion so as to adjust the position of the end in a direction perpendicular to the alignment axis. [Aspect 4] The support jig according to embodiment 3, wherein the second part is linearly adjustable relative to the first part. [Aspect 5] The support jig according to embodiment 4, wherein the second part expands and contracts relative to the first part. [Aspect 6] The support fixture according to any one of embodiments 1 to 5, wherein the aforementioned end portion is provided with a recess for receiving a test piece. [Aspect 7] The support fixture according to any one of embodiments 1 to 6, wherein the pair of supports includes a first support and a second support, and the first support is adjustable on the frame to adjust the position of the first support on the alignment axis in the axial direction. [Aspect 8] The support fixture according to embodiment 7, wherein the second support is adjustable on the frame to adjust the position of the second support on the alignment axis in the axial direction. [Aspect 9] Each support is a support fixture according to any one of embodiments 1 to 8, comprising a recess or protrusion that is spaced apart from the alignment axis and complementary to the protrusion or recess provided on the associated specimen holder which can be fixed to the support. [Aspect 10] A support fixture according to any one of embodiments 1 to 8, wherein each support provides a mounting opening for receiving a portion of the test specimen holder. [Aspect 11] A support jig according to any one of embodiments 1 to 10, wherein each end of the support includes a removable portion that can be fixed to the end. [Aspect 12] The support fixture according to embodiment 11, wherein the end portion and the removable portion of each support include a surface complementary to the specimen holder and capable of engaging with the specimen holder. [Aspect 13] A support fixture according to any one of embodiments 1 to 12, further comprising a first specimen holder that can be detachably fixed to one of the support bodies, and a second specimen holder that can be detachably fixed to the other of the support bodies. [Aspect 14] The support fixture according to embodiment 13, wherein the first specimen holder and the second specimen holder each include a head configured to hold the end of the specimen and a base attached to the head, the base having ends configured to be attached to the tensile testing machine. [Aspect 15] The support fixture according to embodiment 14, wherein each end of each support is releasably engaged with the outer surface of the base of each corresponding specimen holder. [Aspect 16] Each of the test specimen holders is a support fixture according to embodiment 15, which includes a mechanism for applying a preload clamping force to the end of the test specimen. [Aspect 17] A support fixture according to any one of embodiments 13 to 17, wherein each of the first specimen holder and the second specimen holder includes a movable jaw for engaging with and holding the end of the specimen. [Aspect 18] A method for loading a test specimen into a tensile testing machine having a first test specimen holder and a second test specimen holder, To provide a support jig located away from the aforementioned testing machine, The first and second test piece holders are attached to the support fixture such that the heads configured to hold the ends of the test pieces face each other, and the ends of the test piece holders, which can be fixed to the testing machine, face in opposite directions, wherein the test piece holders are aligned with each other and positioned on a common alignment axis. The heads of the first specimen holder and the second specimen holder are fixed to the first and second ends of the specimen, respectively. A method for attaching the first specimen holder and the second specimen holder to the tensile testing machine, wherein the support fixture holds the first specimen holder and the second specimen holder in a spatial relationship fixed to each other on the alignment axis. [Aspect 19] The method according to embodiment 18, wherein the fixture includes a specimen support, and the method further comprises mounting the specimen to the specimen support so as to be aligned with the alignment axis. [Aspect 20] The method according to embodiment 19, wherein the test piece is attached to the test piece support so as to be aligned with the alignment axis, before the heads of the first test piece holder and the second test piece holder are fixed to the test piece. [Aspect 21] The jig includes a first support and a second support connected to a frame, and the method according to any one of embodiments 18 to 20, wherein attaching the first specimen holder and the second specimen holder to the support jig includes attaching the first specimen holder to the first support and attaching the second specimen holder to the second support. [Aspect 22] The method according to any one of embodiments 18 to 21, wherein attaching the first specimen holder and the second specimen holder to the tensile testing machine is performed after attaching the first specimen holder and the second specimen holder to the support fixture and / or after fixing the heads of the first specimen holder and the second specimen holder to the specimen. [Aspect 23] The method according to any one of embodiments 18 to 22, wherein attaching the first specimen holder and the second specimen holder to the support jig includes fixing the respective rotational positions of the first specimen holder and the second specimen holder around the alignment axis. [Aspect 24] The method according to any one of embodiments 18 to 23, wherein fixing the heads of the first specimen holder and the second specimen holder to the first and second ends of the specimen, respectively, includes applying a preload clamping force to the end of the specimen. [Pattern 25] A head body having a first inclined body surface and a second inclined body surface facing each other, A first wedge and a second wedge located within the head body, wherein the first wedge has a first inclined wedge surface that slides in contact with the surface of the first inclined body, and the second wedge has a second inclined wedge surface that slides in contact with the surface of the second inclined body, A support shaft having a first end that can be connected to a part of the testing machine and a second end that supports the first wedge and the second wedge, A drive supported by the support shaft and located between the second end and the first end, A test piece holder comprising a spring connected to the head body at a first end and connected to the drive at a second end. [Aspect 26] The test piece holder according to embodiment 25, wherein the drive is configured to pull the second end of the spring away from the head body. [Aspect 27] The specimen holder according to embodiment 26, wherein the drive comprises a first portion movable relative to a second portion, the first portion connected to the second end of the spring, and the second portion engaging with or securely joining a portion of the support shaft. [Aspect 28] The specimen holder according to embodiment 27, wherein the first portion moves axially with respect to the support shaft. [Aspect 29] The specimen holder according to embodiment 28, wherein the drive includes a driven portion that contacts and is movable relative to the first portion and the second portion. [Aspect 30] The specimen holder according to embodiment 29, wherein the driven portion is movable toward and away from the longitudinal axis of the support shaft. [Aspect 31] The specimen holder according to embodiment 30, wherein the drive includes an actuator supported by the first portion that contacts the driven portion. [Aspect 32] The test piece holder according to embodiment 31, wherein the actuator comprises a drive screw that screws into the first part. [Aspect 33] The test piece holder according to embodiment 32, wherein the engaging surfaces of the driven portion and the second portion include an inclined surface on at least one of the driven portion and / or the second portion. [Aspect 34] The test piece holder according to embodiment 32, wherein the engaging surfaces of the driven portion and the second portion are inclined surfaces. [Aspect 35] The specimen holder according to embodiment 34, wherein the drive includes a wall forming a chamber around the support shaft, and the driven element is disposed within the chamber. [Aspect 36] The test piece holder according to embodiment 35, wherein the drive includes an end cap joined to the end of the wall. [Aspect 37] The spring is a test piece holder according to any one of embodiments 25 to 36, comprising a plurality of longitudinal spring elements arranged around the support shaft. [Aspect 38] The spring is a test piece holder according to embodiment 37, comprising a cylindrical body having longitudinal slots. [Aspect 39] The second portion is a test piece holder according to any one of embodiments 25 to 39, which is securely joined to the support shaft. [Aspect 40] The specimen holder according to embodiment 39, wherein the second portion is integrally joined to the support shaft, and the second portion and the support shaft are formed from a single, integrated structure. [Aspect 41] The specimen holder according to any one of embodiments 25 to 40, wherein the second portion is separable from the support shaft. [Aspect 42] A test piece holder according to any one of embodiments 25 to 41, wherein at least one of the mount or the head body is provided with an opening that opens to the outer surface and extends inward laterally with respect to the longitudinal axis of the support shaft, or a pin that extends laterally away from the outer surface from the longitudinal axis. [Aspect 43] A head body having a first inclined body surface and a second inclined body surface facing each other, A first wedge and a second wedge are located within the head body, wherein the first wedge has a first inclined wedge surface that slides in contact with the surface of the first inclined body, and the second wedge has a second inclined wedge surface that slides in contact with the surface of the second inclined body. A mount having a bore is joined to the head body at the first end, A support shaft having a first end that is disposed within the bore and supports the first wedge and the second wedge, A test piece holder comprising a spring that biases the support shaft toward the head body. [Aspect 44] The specimen holder according to embodiment 43, wherein the bore includes an inner flange, a first end of the spring that engages with the support shaft, and a second end that engages with the inner flange. [Aspect 45] The specimen holder according to embodiment 44, wherein the spring is a compression spring. [Aspect 46] A test piece holder according to any one of embodiments 43 to 45, comprising an adjustment unit for adjusting the force that biases the support shaft toward the head body. [Aspect 47] The test piece holder according to embodiment 46, wherein the adjustment part comprises an actuator joined to the support shaft. [Aspect 48] The test piece holder according to embodiment 47, wherein the actuator is a screw threaded into the mount. [Aspect 49] A test piece holder according to any one of embodiments 43 to 48, further comprising a handle joined to the support shaft. [Aspect 50] The specimen holder according to embodiment 49, wherein the handle comprises a portion extending in the opposite direction from the longitudinal axis of the support shaft. [Aspect 51] A test piece holder according to any one of embodiments 43 to 50, wherein at least one of the mount or the head body is provided with an opening that opens to the outer surface and extends inward laterally with respect to the longitudinal axis of the support shaft, or a pin that extends laterally away from the outer surface from the longitudinal axis. [Explanation of symbols]

[0067] 1. Material Testing System 2 Longitudinal axis 3. Linear Actuator 5 frames 6 base 7. Support Member 8 Crossheads 8A strut 8B Crosshead 8C Hydraulic Lift 9 Load Cells 10 Support fixture 12 frames 13 Base 14A Support 14B Support 15 test specimens 16 Alignment axis 20 Test specimen support 20A Part 1 20B Part 2 22 End 24 Fasteners 26 Fasteners 26A linear bearing support 26B linear bearing support 28 rails 30 Guides 33 Fasteners 34A bore 34B Bore 34C Bore 36 Standoff 38 Bore 38A end 38B End 40A Removable part 40B Removable part 42 Fasteners 50 pins 100 specimen holders 101 Aperture 102 Mount 104 Head Body 106 Stop Color 118 Support plate 120 Movable Wedge 122 Slanted back 124 Slope 132 Aperture 134 Aperture 140 Support shaft 144 Bore 146 shaft 148 Flange 150 Handle 152 Handle section 154 slots 156 Bore 158 Handle shaft 160 Preload clamping force adjustment section 162 Actuators 200 Second specimen holder 201 Aperture 202 Mount 203 Fasteners 204 Head Body 210 Drive 212A Longitudinal slot 212B part 212C First end 212D Second end 214 Part 1 216 Part 2 216A Aperture 220 Second Wedge 228 Driven part 228A aperture 230 Actuator 230A First actuator 230B Second actuator 234 Wall 236 Chambers 238 End cap 240 Support shaft 240A First end 240B Second end 280 Intermediate Holder 282 Intermediate holder 282 Grip

Claims

1. In a support fixture used with a testing machine that applies tensile load, Frame and, A pair of spaced-apart supports joined to the frame to provide an alignment axis, The system comprises a test specimen support joined to the frame between the pair of spaced-apart supports, Each support holds the specimen holder in a fixed spatial relationship on the alignment axis in a detachable manner, with the ends of the specimen holder that can be attached to the testing machine facing in opposite directions. The specimen support has an end configured to hold the specimen on the alignment axis, The specimen support comprises a first portion joined to the frame and a second portion having the end, the second portion being adjustablely fixed to the first portion so as to adjust the position of the end in a direction perpendicular to the alignment axis. The second part is a support jig that is linearly adjustable relative to the first part so that the second part expands and contracts relative to the first part.

2. The support jig according to claim 1, wherein the end portion is provided with a recess for receiving a test piece.

3. The pair of supports includes a first support and a second support, the first support being adjustable on the frame to adjust the position of the first support on the alignment axis in the axial direction, The support jig according to claim 1, wherein the second support is adjustable on the frame to adjust the position of the second support on the alignment axis in the axial direction.

4. The support fixture according to claim 1, wherein each support includes a recess or protrusion that is spaced apart from the alignment axis and is complementary to the protrusion or recess provided on an associated specimen holder that can be fixed to the support.

5. The support fixture according to claim 1, wherein each support provides a mounting opening for receiving a portion of the test piece holder.

6. Each end of the support includes a removable portion that can be fixed to the end. The support fixture according to claim 1, wherein the end portion and the removable portion of each support include a surface complementary to the specimen holder and capable of engaging with the specimen holder.

7. The system further comprises a first specimen holder that can be detachably fixed to one of the support bodies, and a second specimen holder that can be detachably fixed to the other of the support bodies. The first specimen holder and the second specimen holder each include a head configured to hold the end of the specimen and a base attached to the head, the base being configured to be attached to the tensile testing machine. Each end of each support is configured to engage releasably with the outer surface of the base of each corresponding specimen holder. The support fixture according to claim 1, wherein each of the test specimen holders includes a mechanism for applying a preload clamping force to the end of the test specimen.

8. A method for loading a test specimen into a tensile testing machine having a first test specimen holder and a second test specimen holder, To provide a support jig located away from the aforementioned testing machine, The first and second test piece holders are attached to the support fixture such that the heads configured to hold the ends of the test pieces face each other, and the ends of the test piece holders, which can be fixed to the testing machine, face in opposite directions, wherein the test piece holders are aligned with each other and positioned on a common alignment axis. The heads of the first test specimen holder and the second test specimen holder are fixed to the first end and the second end of the test specimen, respectively. A method comprising attaching the first specimen holder and the second specimen holder to the tensile testing machine, wherein the support fixture holds the first specimen holder and the second specimen holder in a spatial relationship fixed to each other on the alignment axis.

9. The fixture includes a specimen support, and the method further includes mounting the specimen to the specimen support so as to be aligned with the alignment axis, The method according to claim 8, wherein the test piece is attached to the test piece support so as to be aligned with the alignment axis, before the heads of the first test piece holder and the second test piece holder are fixed to the test piece.

10. The method according to claim 8, wherein the fixture includes a first support and a second support connected to a frame, and attaching the first specimen holder and the second specimen holder to the support fixture includes attaching the first specimen holder to the first support and attaching the second specimen holder to the second support.

11. The method according to claim 8, wherein attaching the first specimen holder and the second specimen holder to the tensile testing machine is performed after attaching the first specimen holder and the second specimen holder to the support fixture and / or after fixing the heads of the first specimen holder and the second specimen holder to the specimen.

12. The method according to claim 8, wherein attaching the first specimen holder and the second specimen holder to the support jig includes fixing the respective rotational positions of the first specimen holder and the second specimen holder around the alignment axis, and / or fixing the heads of the first specimen holder and the second specimen holder to the first and second ends of the specimen, respectively, includes applying a preload clamping force to the ends of the specimen.

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