Extensometer Structure

Abstract

To provide a suitable extensometer structure.SOLUTION: An extensometer structure (12) comprises a first extension arm (34) having a first attachment part (44) configured to support a first specimen engagement member (58); and a second extension arm (36) having a second attachment part (46) configured to support a second specimen engagement member (58). Connection members (76, 76') extend between the first and second extension arms (34, 36), and between each corresponding attachment part (44, 46) and a distal end of the extension arms (34, 36), are pivotally connected to the first and second extension arms (34, 36), respectively. A rear coupling assembly connects the distal ends of the extension arms (34, 36) together.SELECTED DRAWING: Figure 1

Description

[Background technology]

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

[0002] Extensometers are commonly used to measure strain in a specimen. Numerous forms of extensometers have been advanced in the art. One type of extensometer utilizes two extension arms held together by a cross-flex assembly. The flexion member of the cross-flex assembly forms a pivot axis that allows the extension arms to pivot relative to one another to measure strain in the specimen. This form of extensometer works fairly well, but improvements can be made. Summary of the Invention [Problem to be solved by the invention]

[0003] (overview) This Summary and Abstract herein are provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary and Abstract are not intended to identify key features or essential features of the claimed subject matter, nor are they 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 solve any or all of the disadvantages noted in the Background.

[0004] One general aspect includes an extensometer structure including a first extending arm having a first mounting portion configured to support a first specimen engaging member, a second extending arm having a second mounting portion configured to support a second specimen engaging member, a connecting member extending between the first and second extending arms and pivotally connected to each of the first and second extending arms between their respective mounting portions and a distal end of the extending arm, and a back coupling assembly connecting the distal ends of the extending arms together.

[0005] Implementations may include one or more of the following features: an extensometer structure, where the rear coupling assembly includes at least one coupling link and a pivot assembly connected in series to the distal ends of the first and second extending arms; an extensometer structure, where the at least one connecting link and pivot assembly includes a connecting link connected to the distal end of the first extending arm and a pivot assembly including a first portion connected to the distal end of the second extending arm and a second portion pivoted relative to the first portion and connected to the connecting link at an end opposite the end connected to the first extending arm; an extensometer structure, where the connecting link includes a flexure; an extensometer structure, where the pivot assembly includes a cross flexure assembly; an extensometer structure, where the second pivot connection, the pivot axis of the cross flexure, and the pivot connection between the second extending arm and the connecting member are in common line with each other. an extensometer structure, wherein the spacing between the first and second pivot connections is approximately equal to the spacing of the pivot connections connecting the first and second extension arms to the connecting member, and wherein the connecting link includes a rigid link having a first pivot connection connected to the first extension arm and a second pivot connection connected to a second portion of the pivot assembly.

[0006] An extensometer structure, wherein the fixing assembly has a movable locking member configured to engage each of the extended arms and selectively hold the arms in a fixed position relative to one another. An extensometer structure, wherein the fixing assembly is disposed between the connecting member and the coupling link. An extensometer structure, wherein the fixing assembly includes a locking member that pivots or rotates relative to at least one of the extended arms. An extensometer structure, wherein the fixing assembly includes a rotatable shaft extending through the first extended arm and the second extended arm. An extensometer structure, wherein the fixing assembly includes a first cam secured to the shaft for rotation therewith and selectively engageable with the first extended arm, and a second cam secured to the shaft for rotation therewith and selectively engageable with the second extended arm. An extensometer structure, wherein the first extension arm includes a first opening and the second extension arm includes a second opening, a rotatable shaft extends through the first opening and the second opening, a first cam is disposed in the first opening and a second cam is disposed in the second opening. An extensometer structure, wherein the locking member moves linearly relative to at least one of the extension arms. An extensometer structure, wherein the fixation assembly includes a locking plate including a portion that releasably engages with a portion of each of the extension arms. An extensometer structure, wherein the locking plate extends through an opening provided in each of the extension arms. An extensometer structure, further including a force generating assembly coupled to the extensometer arm having a spring element to bias the extension arm towards the specimen. An extensometer structure, wherein the force generating assembly includes a control element, the control element being joined to the spring element, the control element being movable relative to a stationary member. An extensometer structure, wherein the locking plate moves with the control element. An extensometer structure, wherein the spring element is connected to a connecting member. The extensometer structure, wherein the connecting member includes an H-shaped member having an upper free end pivotally connected to a first extension arm and a lower free end pivotally connected to a second extension arm, the H-shaped member having a central portion disposed between the first and second extension arms, and the spring element includes a first spring element on a first side of the extension arm and a second spring element on a second side of the extension arm.The extensometer structure, wherein the force generating assembly further includes a movable mounting block pivotally connected to the connecting member, and each of the spring elements is joined to the movable mounting block. The extensometer structure, wherein each of the spring elements includes a flexure. The extensometer structure, wherein each of the spring elements includes a pair of parallel flexures. The extensometer structure, wherein the locking plate moves relative to the control element.

[0007] An extensometer structure further comprising a user-adjustable driver connected to the control element to adjust a position of the control element relative to the stationary member. The extensometer structure, wherein the user-adjustable driver comprises a rotatable threaded member configured to adjust a position of the control element relative to the stationary member. The extensometer structure, wherein the user-adjustable driver comprises a movable block in sliding engagement with the control element. The extensometer structure, wherein the movable block is slidable within the stationary member. The extensometer structure, wherein the movable block has a variable width between the sliding engagement with the control element and the stationary member. The extensometer structure, wherein the movable block is movable to any of a plurality of repeatable positions relative to the stationary member. The extensometer structure, further comprising a scale indicating a position of each of the plurality of repeatable positions. The extensometer structure, further comprising a fixation device for selectively fixing the movable block to the stationary member.

[0008] Another general aspect includes an extensometer structure including a first extension arm and a second extension arm movably connected to the first extension arm, the extensometer structure also including a fastening assembly coupled to each of the first extension arm and the second extension arm configured to selectively fasten the first extension arm to the second extension arm.

[0009] Implementations may include one or more of the following features: An extensometer structure, wherein the fixation assembly includes a rotatable shaft extending through a first extended arm and a second extended arm; An extensometer structure, wherein the fixation assembly includes a first cam secured to the shaft for rotation therewith and selectively engageable with the first extended arm and a second cam secured to the shaft for rotation therewith and selectively engageable with the second extended arm; An extensometer structure, wherein the first extended arm includes a first opening and the second extended arm includes a second opening, the rotatable shaft extends through the first opening and the second opening, the first cam is disposed within the first opening and the second cam is disposed within the second opening; An extensometer structure, wherein the fixation assembly includes an arm disposed between the first extended arm and the second extended arm, the arm rotatably coupled to the rotatable shaft; An extensometer structure, wherein a connecting member, pivotally connected to each of the extended arms. An extensometer structure, wherein the connecting member includes an H-shaped member having an upper free end pivotally connected to a first extending arm and a lower free end pivotally connected to a second extending arm, the H-shaped member having a central location disposed between the first and second extending arms. An extensometer structure, wherein the mounting is pivotally connected to the connecting member and the arm is connected to the mounting. An extensometer structure, wherein the fixation assembly includes a locking plate including a portion that releasably engages with a portion of each of the extending arms. An extensometer structure, wherein the locking plate extends through an opening provided in each of the extending arms. An extensometer structure, further including a force generating assembly coupled to the extensometer arms with a spring element to bias the extending arms towards the specimen. An extensometer structure, wherein the force generating assembly includes a control element, the spring element joining the extensometer structure to the control element, the control element being movable relative to a stationary member. An extensometer structure, wherein the locking plate moves with the control element. An extensometer structure, wherein the locking plate moves relative to the control element.

[0010] Yet another general aspect includes an extensometer structure including a mounting assembly having a first mounting block movable relative to a second mounting block, and an extensometer structure joined to the second mounting block and including: The extensometer structure also includes a first extension arm; The extensometer structure also includes a second extension arm movably connected to the first extension arm; The extensometer structure may also include a force generating assembly coupled to the extensometer structure with a spring element to bias the extension arm toward the specimen.

[0011] Implementations may include one or more of the following features: An extensometer structure, wherein the force generating assembly includes a control element, a spring element joining the extensometer structure to the control element, the control element being movable relative to a stationary member; An extensometer structure, wherein the force generating assembly includes a connecting member pivotally connected to each of the extension arms, the spring element being connected to the connecting member; An extensometer structure, wherein the connecting member includes an H-shaped member having an upper free end pivotally connected to a first extension arm and a lower free end pivotally connected to a second extension arm, the H-shaped member having a central portion disposed between the first and second extension arms; An extensometer structure, wherein the spring element includes a first spring element on a first side of the extension arm and a second spring element on a second side of the extension arm; An extensometer structure, wherein the force generating assembly includes a movable mounting block pivotally connected to the connecting member, each of the spring elements being joined to the movable mounting block; An extensometer structure, wherein each of the spring elements includes a bend. An extensometer structure, wherein each of the spring elements includes a pair of parallel bends. An extensometer structure, further including a user-adjustable driver connected to the control element to adjust a position of the control element relative to the stationary member. An extensometer structure, wherein the user-adjustable driver includes a rotatable threaded member configured to adjust a position of the control element relative to the stationary member. An extensometer structure, wherein the user-adjustable driver includes a movable block that slidingly engages the control element. An extensometer structure, wherein the movable block is slidable within the stationary member. An extensometer structure, wherein the movable block has a variable width between its sliding engagement with the control element and the stationary member. An extensometer structure, wherein the movable block is movable relative to the stationary member to any of a plurality of repeatable positions. An extensometer structure, further including a scale indicating a position of each of the plurality of repeatable positions. An extensometer structure, further including a fixation device for selectively fixing the movable block to the stationary member.

[0012] Another general aspect includes an extensometer structure including a first extending arm and a second extending arm movably connected to the first extending arm. The extensometer structure also includes a first mounting portion configured to hold a first sample engaging device, the first mounting portion connected to the first extending arm at a first bend that allows movement of the first mounting portion relative to the first extending arm. The extensometer structure also includes a second mounting portion configured to hold a second sample engaging device, the second mounting portion connected to the second extending arm.

[0013] Implementations may include one or more of the following features: an extensometer structure, the first flexure configured to allow free lateral movement of the first mounting, the lateral movement being orthogonal to an axis of extension of the first extension arm; an extensometer structure further including a second flexure joining the second mounting to the second extension arm, the second flexure configured to allow free lateral movement of the second mounting, the lateral movement being orthogonal to an axis of extension of the second extension arm; an extensometer structure further including a second flexure joining the second mounting to the second extension arm, the second flexure configured to allow free lateral movement of the second mounting, the lateral movement being orthogonal to a plane having a first axis of extension of the first extension arm and a second axis of extension of the second extension arm. An extensometer structure, wherein the first bend is configured to allow free lateral movement of the first attachment, the lateral movement being perpendicular to a plane having a first axis of extension of the first extension arm and a second axis of extension of the second extension arm. An extensometer structure, wherein the first bend is configured to allow selected and fixed positioning of the first attachment relative to the first extension arm. An extensometer structure, wherein the first bend includes a first end fixedly joined to the first extension arm and a second end joined to the first attachment, the second end including an adjustable member for adjusting a spacing between the second end and the first extension arm. An extensometer structure, wherein the first bend is configured to allow selected and fixed positioning of the first attachment relative to the first extension arm. An extensometer structure, wherein the first flexure is configured to allow for selected and fixed positioning of the first mounting portion relative to the first extension arm to adjust the spacing between the first mounting portion and the second mounting portion.

[0014] Yet another general aspect includes an extensometer structure including a first extended arm having a first mounting configured to support a first specimen engaging member and a second extended arm having a second mounting configured to support a second specimen engaging member. The extensometer structure also includes a connection member pivotally connected to each of the extended arms, a first counterweight attached to the first extended arm on a first side of the connection member, the first counterweight being a mass that offsets at least some of the mass present on the first extended arm on a second side of the connection member opposite the first counterweight, and a second counterweight attached to the second extended arm on the first side of the connection member, the second counterweight being a mass that offsets at least some of the mass present on the second extended arm on a second side of the connection member opposite the second counterweight.

[0015] Implementations may include one or more of the following features: An extensometer structure further including a mount connected to each end of the arm, each mount configured to hold a specimen for engagement therewith, and each of the counterweights joined to each corresponding mount; An extensometer structure, wherein each counterweight includes an opening through which a specimen engaging member attached to each associated mount may extend; An extensometer structure, wherein each counterweight includes an extending flange, the extending flanges overlapping one another in a spaced apart relationship; An extensometer structure, wherein each counterweight includes a reflective outer surface for reflecting thermal energy.

[0016] Another general aspect includes an extensometer structure including a first extending arm and a second extending arm movably connected to the first extending arm. The extensometer structure also includes a first mounting portion connected to an end of the first extending arm and configured to hold a first sample engaging device. The extensometer structure also includes a second mounting portion to an end of the second extending arm configured to hold a second sample engaging device, the second mounting portion connected to the second extending arm. The extensometer structure also includes a cooling passage in each mounting portion and associated end of each extending arm.

[0017] Implementations may include one or more of the following features: an extensometer structure, wherein each passageway includes a cooling tube; an extensometer structure, wherein a plurality of cooling lines fluidly connect each of the passageways to an inlet port and an outlet port; an extensometer structure, wherein the passageways are connected in series with each other and the inlet and outlet ports. The present invention provides, for example, the following: (Item 1) An extensometer structure, the extensometer structure comprising: a first extension arm having a first mounting portion configured to support a first specimen engagement member; a second extension arm having a second mounting portion configured to support a second specimen engaging member; a connecting member extending between the first and second extended arms and pivotally connected to each of the first and second extended arms between a respective mounting portion and a distal end of the extended arm; a rear coupling assembly connecting together the distal ends of the extension arms; 1. An extensometer structure comprising: (Item 2) 2. The extensometer structure of claim 1, wherein the rear coupling assembly comprises at least one coupling link and a pivot assembly connected in series to the distal ends of the first extension arm and the second extension arm. (Item 3) 3. The extensometer structure of claim 2, wherein the at least one connecting link and pivot assembly comprises: the connecting link connected to the distal end of the first extending arm; and the pivot assembly comprising a first portion connected to the distal end of the second extending arm; and a second portion pivoting relative to the first portion and connected to the connecting link at an end opposite the end connected to the first extending arm. (Item 4) Item 4. The extensometer structure of item 3, wherein the connecting link comprises a bend. (Item 5) Item 4. The extensometer structure of item 3, wherein the connecting link comprises a rigid link having a first pivot connection connected to the first extension arm and a second pivot connection connected to the second portion of the pivot assembly. (Item 6) Item 5. The extensometer structure of item 4, wherein the pivot assembly comprises a cross flex assembly. (Item 7) Item 5. The extensometer structure of item 4, wherein the second pivot connection, the pivot axis of the cross bend, and the pivot connection between the second extension arm and the connecting member are colinear with one another. (Item 8) 8. The extensometer structure of claim 7, wherein the spacing between the first and second pivot connections is approximately equal to the spacing of the pivot connections connecting the first and second extension arms to the connecting member. (Item 9) Item 3. The extensometer structure of item 2, wherein the fixation assembly has a movable locking member configured to engage each of the extension arms and selectively hold the arms in a fixed position relative to one another. (Item 10) 10. The extensometer structure of claim 9, wherein the fastening assembly is disposed between the connecting member and the coupling link. (Item 11) Item 11. The extensometer structure of item 10, wherein the fixation assembly comprises a locking member that pivots or rotates relative to at least one of the extension arms. (Item 12) Item 12. The extensometer structure of item 11, wherein the fixture assembly comprises a rotatable shaft extending through the first extension arm and the second extension arm. (Item 13) The fastening assembly includes: a first cam secured to the shaft for rotation therewith, the first cam being selectively engagable with the first extension arm; a second cam secured to the shaft for rotation therewith, the second cam being selectively engageable with the second extension arm; Item 13. The extensometer structure of item 12, comprising: (Item 14) Item 14. The extensometer structure of item 13, wherein the first extension arm includes a first opening and the second extension arm includes a second opening, the rotatable shaft extends through the first opening and the second opening, the first cam is disposed within the first opening and the second cam is disposed within the second opening. (Item 15) Item 11. The extensometer structure of item 10, wherein the locking member moves linearly relative to at least one of the extension arms. (Item 16) Item 11. The extensometer structure of item 10, wherein the fixation assembly comprises a locking plate including a portion that releasably engages a portion of each of the extension arms. (Item 17) Item 17. The extensometer structure of item 16, wherein the locking plate extends through an opening provided in each of the extension arms. (Item 18) Item 18. The extensometer structure of item 17, further comprising a force generating assembly coupled to the extensometer arm having a spring element for biasing the extension arm towards a specimen. (Item 19) 20. The extensometer structure of claim 18, wherein the force generating assembly includes a control element, the control element being joined to the spring element, the control element being movable relative to a stationary member. (Item 20) 20. The extensometer structure of claim 19, wherein the locking plate moves with the control element. (Item 21) 20. The extensometer structure of claim 19, wherein the locking plate moves relative to the control element. (Item 22) 20. The extensometer structure of claim 19, further comprising a user adjustable driver connected to the control element for adjusting a position of the control element relative to the stationary member. (Item 23) Item 23. The extensometer structure of item 22, wherein the user-adjustable driver comprises a rotatable threaded member configured to adjust the position of the control element relative to the stationary member. (Item 24) Item 24. The extensometer structure of item 23, wherein the user-adjustable driver comprises a movable block that slidably engages the control element. (Item 25) 25. The extensometer structure of claim 24, wherein the movable block is slidable within the stationary member. (Item 26) 26. The extensometer structure of claim 25, wherein the movable block has a variable width between its sliding engagement with the control element and the stationary member. (Item 27) 27. The extensometer structure of claim 25 or 26, wherein the movable block is movable relative to the stationary member to any of a plurality of repeatable positions. (Item 28) Item 28. The extensometer structure of item 27, further comprising a scale indicating a position of each of the plurality of repeatable positions. (Item 29) 28. The extensometer structure of any one of claims 25 to 27, further comprising a fastening device for selectively fastening the movable block to the stationary member. (Item 30) 28. The extensometer structure of any one of claims 18 to 27, wherein the spring element is connected to the connecting member. (Item 31) Item 31. The extensometer structure of item 30, wherein the connecting member comprises an H-shaped member having an upper free end pivotally connected to the first extension arm and a lower free end pivotally connected to the second extension arm, the H-shaped member having a central portion disposed between the first and second extension arms. (Item 32) Item 32. The extensometer structure of item 31, wherein the spring element comprises a first spring element on a first side of the extension arm and a second spring element on a second side of the extension arm. (Item 33) Item 33. The extensometer structure of item 32, wherein the force generating assembly further comprises a movable mounting block pivotally connected to the connecting member, each of the spring elements being joined to the movable mounting block. (Item 34) Item 34. The extensometer structure of item 33, wherein each of the spring elements comprises a bend. (Item 35) Item 34. The extensometer structure of item 33, wherein each of the spring elements comprises a pair of parallel flexures. (Item 36) An extensometer structure, the extensometer structure comprising: A first extension arm; a second extension arm movably connected to the first extension arm; a fastening assembly coupled to each of the first extension arm and the second extension arm configured to selectively fasten the first extension arm to the second extension arm; 1. An extensometer structure comprising: (Item 37) Item 37. The extensometer structure of item 36, wherein the fixture assembly comprises a rotatable shaft extending through the first extension arm and the second extension arm. (Item 38) The fastening assembly includes: a first cam secured to the shaft for rotation therewith, the first cam being selectively engagable with the first extension arm; a second cam secured to the shaft for rotation therewith, the second cam being selectively engageable with the second extension arm; 38. The extensometer structure of item 37, comprising: (Item 39) Item 39. The extensometer structure of item 38, wherein the first extension arm includes a first opening and the second extension arm includes a second opening, the rotatable shaft extends through the first opening and the second opening, the first cam is disposed within the first opening and the second cam is disposed within the second opening. (Item 40) 40. The extensometer structure of any one of claims 37 to 39, wherein the fixation assembly comprises an arm disposed between the first extension arm and the second extension arm, the arm being rotatably coupled to the rotatable shaft. (Item 41) 40. The extensometer structure of any one of claims 37 to 39, wherein the fixation assembly comprises a locking plate including a portion that releasably engages with a portion of each of the extension arms. (Item 42) Item 42. The extensometer structure of item 41, wherein the locking plate extends through an opening provided in each of the extension arms. (Item 43) Item 42. The extensometer structure of item 41, further comprising a force generating assembly coupled to the extensometer arm with a spring element to bias the extension arm towards a specimen. (Item 44) Item 44. The extensometer structure of item 43, wherein the force generating assembly includes a control element, the spring element joins the extensometer structure to the control element, the control element being movable relative to a stationary member. (Item 45) Item 45. The extensometer structure of item 44, wherein the locking plate moves with the control element. (Item 46) Item 45. The extensometer structure of item 44, wherein the locking plate moves relative to the control element. (Item 47) Item 41. The extensometer structure of item 40, wherein a connecting member is pivotally connected to each of said extension arms. (Item 48) Item 48. The extensometer structure of item 47, wherein the connecting member comprises an H-shaped member having an upper free end pivotally connected to the first extension arm and a lower free end pivotally connected to the second extension arm, the H-shaped member having a central portion disposed between the first and second extension arms. (Item 49) Item 49. The extensometer structure of item 48, wherein a mounting portion is pivotally connected to the connecting member and the arm is connected to the mounting portion. (Item 50) An extensometer structure, the extensometer structure comprising: a mounting assembly having a first mounting block movable relative to a second mounting block; an extensometer structure bonded to the second mounting block, the extensometer structure comprising: A first extension arm; a second extension arm movably connected to the first extension arm; an extensometer structure comprising: a force generating assembly coupled to the extensometer structure by a spring element for biasing the extension arm toward a specimen; 1. An extensometer structure comprising: (Item 51) Item 51. The extensometer structure of item 50, wherein the force generating assembly includes a control element, the spring element joining the extensometer structure to the control element, the control element being movable relative to a stationary member. (Item 52) Item 51. The extensometer structure of item 50, further comprising a user adjustable driver connected to the control element for adjusting a position of the control element relative to the stationary member. (Item 53) Item 53. The extensometer structure of item 52, wherein the user-adjustable driver comprises a rotatable threaded member configured to adjust the position of the control element relative to the stationary member. (Item 54) Item 54. The extensometer structure of item 53, wherein the user-adjustable driver comprises a movable block that slidably engages the control element. (Item 55) Item 55. The extensometer structure of item 54, wherein the movable block is slidable within the stationary member. (Item 56) Item 56. The extensometer structure of item 55, wherein the movable block has a variable width between its sliding engagement with the control element and the stationary member. (Item 57) 57. The extensometer structure of claim 55 or 56, wherein the movable block is movable relative to the stationary member to any of a plurality of repeatable positions. (Item 58) Item 58. The extensometer structure of item 57, further comprising a scale indicating a position of each of the plurality of repeatable positions. (Item 59) 58. The extensometer structure of any one of claims 55 to 57, further comprising a fastening device for selectively fastening the movable block to the stationary member. (Item 60) 58. The extensometer structure of any one of items 50 to 57, wherein the force generating assembly comprises a connecting member pivotally connected to each of the extension arms, the spring element being connected to the connecting member. (Item 61) Item 61. The extensometer structure of item 60, wherein the connecting member comprises an H-shaped member having an upper free end pivotally connected to the first extension arm and a lower free end pivotally connected to the second extension arm, the H-shaped member having a central portion disposed between the first and second extension arms. (Item 62) Item 62. The extensometer structure of item 61, wherein the spring element comprises a first spring element on a first side of the extension arm and a second spring element on a second side of the extension arm. (Item 63) Item 63. The extensometer structure of item 62, wherein the force generating assembly further comprises a movable mounting block pivotally connected to the connecting member, each of the spring elements being joined to the movable mounting block. (Item 64) Item 64. The extensometer structure of item 63, wherein each of the spring elements comprises a bend. (Item 65) Item 64. The extensometer structure of item 63, wherein each of the spring elements comprises a pair of parallel flexures. (Item 66) A first extension arm; a second extension arm movably connected to the first extension arm; a first mounting configured to hold a first sample engaging device, the first mounting connected to the first extension arm at a first bend allowing movement of the first mounting relative to the first extension arm; a second mounting portion configured to hold a second sample engaging device, the second mounting portion being connected to the second extension arm; 1. An extensometer structure comprising: (Item 67) Item 67. The extensometer structure of item 66, wherein the first flexure is configured to allow free lateral movement of the first mounting portion, the lateral movement being perpendicular to an axis of extension of the first extension arm. (Item 68) Item 67. The extensometer structure of item 66, wherein the first flexure is configured to allow free lateral movement of the first mounting portion, the lateral movement being perpendicular to a plane having a first axis of extension of the first extension arm and a second axis of extension of the second extension arm. (Item 69) Item 70. The extensometer structure of item 68, wherein the first flexure is configured to allow for selected and fixed positioning of the first attachment portion relative to the first extension arm. (Item 70) Item 67. The extensometer structure of item 66, wherein the first flexure is configured to allow for selected and fixed positioning of the first attachment portion relative to the first extension arm. (Item 71) Item 67. The extensometer structure of item 66, wherein the first flexure is configured to allow selected and fixed positioning of the first mounting portion relative to the first extension arm to adjust spacing between the first mounting portion and the second mounting portion. (Item 72) 72. The extensometer structure of any one of claims 69 to 71, wherein the first bend portion has a first end fixedly secured to the first extension arm and a second end secured to the first mounting portion, the second end including an adjustable member for adjusting a spacing between the second end and the first extension arm. (Item 73) 73. The extensometer structure of any one of items 66 to 72, further comprising a second flexure joining the second mounting portion to the second extension arm, the second flexure configured to allow free lateral movement of the second mounting portion, the lateral movement being perpendicular to an axis of extension of the second extension arm. (Item 74) 73. The extensometer structure of any one of items 66 to 72, further comprising a second flexure joining the second mounting portion to the second extension arm, the second flexure configured to allow free lateral movement of the second mounting portion, the lateral movement being perpendicular to a plane having a first axis of extension of the first extension arm and a second axis of extension of the second extension arm. (Item 75) a first extension arm having a first mounting portion configured to support a first specimen engagement member; a second extension arm having a second mounting portion configured to support a second specimen engaging member; a connecting member pivotally connected to each of the extension arms; a first counterweight attached to the first extension arm on a first side of the connecting member, the first counterweight having a mass that offsets at least some of the mass present on the first extension arm on a second side of the connecting member opposite the first counterweight; a second counterweight attached to the second extension arm on the first side of the connecting member, the second counterweight being a mass that offsets at least some of the mass present on the second extension arm on the second side of the connecting member opposite the second counterweight; 1. An extensometer structure comprising: (Item 76) Item 76. The extensometer structure of item 75, further comprising a mounting portion connected to each end of the arm, each mounting portion configured to hold a specimen engaging member, each of the counterweights being secured to a respective corresponding mounting portion. (Item 77) Item 77. The extensometer structure of item 76, wherein each counterweight includes an opening through which a specimen engaging member attached to each associated mounting portion can extend. (Item 78) 78. The extensometer structure of any one of claims 75 to 77, wherein each counterweight includes an extending flange, said extending flanges overlapping one another in a spaced apart relationship. (Item 79) 79. The extensometer structure of any one of claims 75 to 78, wherein each counterweight includes a reflective outer surface for reflecting thermal energy. (Item 80) A first extension arm; a second extension arm movably connected to the first extension arm; a first mounting portion connected to an end of the first extension arm and configured to hold a first sample engaging device; a second attachment on an end of the second extension arm configured to hold a second sample engaging device, the second attachment being connected to the second extension arm; wherein each mounting portion and associated end of each extension arm includes a cooling passage. (Item 81) Item 81. The extensometer structure of item 80, wherein each passage is provided with a cooling tube. (Item 82) 82. The extensometer structure of claim 80 or 81, wherein a plurality of cooling lines fluidly connect each of said passages to an inlet port and an outlet port. (Item 83) Item 83. The extensometer structure of item 82, wherein the passages are connected in series with each other and with the inlet and outlet ports. [Brief description of the drawings]

[0018] BRIEF DESCRIPTION OF THE DRAWINGS Further details and advantages emerge from the following description of embodiments of the invention with reference to the drawings.

[0019] [Figure 1] FIG. 1 is a perspective view of an extensometer.

[0020] [Diagram 2] FIG. 2 is a side view of the extensometer of FIG. 1 with portions removed.

[0021] [Diagram 3] FIG. 3 is a schematic side view of a second embodiment of the extensometer.

[0022] [Figure 4] FIG. 4 is a perspective view of the extensometer with portions removed.

[0023] [Diagram 5]5 and 6 are enlarged views of the extensometer of FIG. 1 with portions removed. [Figure 6] 5 and 6 are enlarged views of the extensometer of FIG. 1 with portions removed.

[0024] [Figure 7] 7-9 are enlarged views of the extensometer of FIG. 1 having different connecting links. [Figure 8] 7-9 are enlarged views of the extensometer of FIG. 1 having different connecting links. [Figure 9] 7-9 are enlarged views of the extensometer of FIG. 1 having different connecting links.

[0025] [Figure 10] FIG. 10 is a rear view of the extensometer of FIG.

[0026] [Figure 11] FIG. 11 is a perspective view of a second embodiment of an extensometer.

[0027] [Figure 12] 12 and 13 are perspective views of the extensometer of FIG. 11 with portions removed. [Figure 13] 12 and 13 are perspective views of the extensometer of FIG. 11 with portions removed.

[0028] [Figure 14] FIG. 14 is a perspective view of an extensometer with cooling lines.

[0029] [Figure 15] FIG. 15 is a partial perspective view of an extensometer with a counterweight heat shield. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS An embodiment of an extensometer having aspects of the present invention is illustrated at 10 in FIG. Extensometer 10 includes an extensometer structure 12 that is attached to a mounting assembly 14. As used herein, "extensometer structure" means at least some of the interconnected mechanical components and does not include any sensing devices for measuring movement of the components of the extensometer structure. Rather, various types of sensing devices may be used with the extensometer structures disclosed herein to form an operable extensometer that provides an output signal indicative of displacement, such as elongation, of a specimen.

[0031] The mounting assembly 14 allows the extensometer 10 to be secured to a suitable stationary support, not shown. In the embodiment shown, the mounting assembly 14 includes a mounting block 16 secured to the stationary support. The slide assembly 18 includes a slide plate 22, here attached to the extensometer structure 12 with a plate adapter 26. The slide plate 22 mates with and slides relative to a slide plate 24, which is secured to the mounting block 16. An over-travel stop may comprise, for example, a block 28 secured to one of the slide plates 22 and 24, where the slide plate 22 limits movement of the extensometer structure 12 relative to the mounting assembly 14 due to contact with an overlapping flange 28A of the slide plate 24.

[0032] 2, the extensometer structure 12 includes a first extending arm 34 and a second extending arm 36 that are preferably connected together at their distal ends by a back coupling assembly that includes, in part, a coupling link 38. The first extending arm 34 includes a mounting portion 44 at an end of the extending arm 34 distal from the coupling link 38. Similarly, the second extending arm 36 includes a mounting portion 46 at an end distal from the coupling link 38. The mounting portions 44, 46 are configured to hold a sample engaging device, illustrated here as an elongated rod 58. However, this should not be considered as limiting in that the mounting portions 44, 46 may be configured to hold other end devices, such as, but not limited to, a knife blade or other form of sample engaging device.

[0033] The first aspect disclosed is a force generating assembly 60 that allows a user to adjust the amount of force applied to a specimen by a specimen engaging device attached to the ends of the first and second extension arms 34 and 36, exemplified here by an elongated rod 58. The force generating assembly 60 is particularly advantageous because it is configured to apply a substantially equal force through each of the extension arms 34 and 36. Generally, the force generating assembly 60 includes a coupling assembly 62 that couples the extension arms 34, 36 to equally divide or balance the force applied through the extension arms 34, 36. The force generating assembly 60 also includes a flexing assembly 64, which in turn is alternately connected to a control arm 66. The control arm 66 is movably or adjustably connected to the mounting assembly 14, allowing the control arm 66 to move a portion of the extensometer structure 12 relative to the mounting assembly 14. Referring to FIG. 1, the mounting assembly 14 includes a portion here that includes a reaction block 68. An actuation device 70, here comprising a rotatable screw, enables the control arm 66 to be selectively displaced away from the reaction block 68 when movement of the extensometer structure 12 towards the specimen is desired.

[0034] The flexure assembly 64 couples the control arm 66 to the coupling assembly 62 and functions as a compliant spring. The coupling assembly 62 couples the connecting member 76 and portions of the extension arms 34 and 36 together at a pivot connection 78, thus allowing the connecting member 76 to pivot relative to each of the extension arms 34 and 36. The pivot connection 78 can be any form of pivot connection, preferably with low pivot resistance. In one advantageous embodiment, the pivot connection has non-mating components to avoid friction between the mating portions. A particularly advantageous embodiment is to form the pivot connection using orthogonal cross bends.

[0035] The flexure assembly 64 further includes a flexure mounting block 80 and a flexure mount 82 fixed relative to the control arm 66, to which the flexure mount 82 is fixedly attached. The flexure mounting block 80 is also pivotally connected to the connecting member 76 at a pivot connection 78. At least one flexure member 88 joins the flexure mounting block 80 to the fixed flexure mount 82 and functions as a spring element. Actuation of the actuation device 70 to move the control arm 66 relative to the reaction block 68 of the mounting assembly 14 in turn causes movement of the extension arms 34 and 36 towards the specimen until contact is made with the specimen engagement device, and further movement of the control arm 66 relative to the reaction block 68 towards the specimen engagement device causes deflection of the flexure member 88 to generate a spring force thereon that is applied to the specimen, not shown, through the extension arms 34, 36 and the specimen engagement device, here the elongated rod 58. Moreover, due to the pivotal connection of the flexure mounting block 80 to the connecting member 76 and the pivotal connection of the connecting member 76 to each of the extension arms 34 and 36, a substantially equal force is provided through each of the extension arms 34, 36 and the specimen engagement device. A user can adjust the amount of force applied through the forced displacement of the control arm 66 relative to the reaction block 68 of the mounting assembly 14. The coupling assembly 62 ensures that the forces applied through the extension arms 34, 36 are substantially equal.

[0036] The side view of Fig. 3 shows diagrammatically the elements comprising the force-generating assembly 60, which are the coupling assembly 62, the control arm 66, the connecting member 76, the reaction block 68, the actuation device 70, the pivot connection 78, the flexure mounting block 80, the fixed flexure mounting 82, and at least one spring element, here comprising one or more flexure members 88. In Fig. 3, the force-generating assembly 60 includes two flexure members 88A, 88B provided on opposite sides of the axis of rotation of the pivot connection 78 connecting the flexure mounting block 80 to the connecting member 76. It should be noted that the flexure members 88A, 88B can be secured to the flexure mounting block 80 and the fixed flexure mounting 82 with suitable fastening devices, here comprising, as an example, a mounting block 90 and a suitable fastener such as a threaded screw 92 (Fig. 2).

[0037] 1 and 4-6 illustrate a preferred embodiment of the force generating assembly 60. In this embodiment, the force generating assembly 60 includes at least one flexure member 88 on each side of the extension arms 34 and 36. Preferably, two flexure members 88 are provided on each side to form two parallel spring structures connecting the flexure mounting block 80 to the fixed flexure mount 82. As can be best illustrated in FIG. 4, the connecting member 76 has an "H" configuration, with the extending free arm portion 91 pivotally connected to each of the extension arms 34, 36 at pivot connections 78 (FIGS. 4 and 5), while a central interconnect portion 95 connects the ends 91 together (FIG. 6). When spring elements are provided on each side of the extension arms 34, 36, the flexure mounting blocks 80 on each side of the extension arms 36 are connected together with at least one link, although in a preferred embodiment, a link 100 is provided on each side of the connecting member 76. Preferably, the flexure mounting block 80 and the link(s) 100 are one-piece formed from one unitary body. In the embodiment illustrated in Figure 1, the slide assembly 18 acts as a linear guide to constrain bending of the flexure member 88 in the direction indicated by the double arrow 20.

[0038] In this regard, it should be noted that additional flexure members may be provided at the ends of extension arms 34 and 36 to provide horizontal and vertical compliance and / or adjustability, if desired. Referring to FIG. 5, mount 44 for extension arm 34 includes flexure member 120, either integrally formed within the mount as one unitary body or separately attached to the mount. Flexure member 120 allows for horizontal compliance as indicated by double arrow 122. Double arrow 122 provides for lateral movement of mount 44 relative to the axis of extension of extension arm 34, preferably in a plane defined by the axis of extension of extension arm 34 and the axis of extension of extension arm 36.

[0039] In this embodiment, the mount 46 for the lower extension arm 36 includes a flexure 124 connected to the end of the extension arm 36. The flexure 124 may be a separate block forming part of the mount 46 or may be integrally formed with the mount 46 as one unitary body. The flexure 124 has a first end 124A that is fixably secured to the extension arm 36, while a movable end 124B is connected to or integrally formed with the mount 44. The flexure 124 thus allows the mount 46 to move relative to the end of the extension arm 36 as indicated by the double arrow 126. In a preferred embodiment, the end 124B is adjustable toward or away from the end of the extension arm 36 to adjust the mount 46 connected to the end 124B in the direction indicated by the double arrow 126 to adjust the gauge length or spacing between the mounts 44, 46 or sample engaging devices connected thereto. Referring to FIG. 4, one or more adjustable members, such as screws 125, are used to adjust the gap between end 124B and the end of extension arm 36.

[0040] Another aspect of the disclosure includes an arm locking assembly 140 that selectively locks the extension arms 34 and 36 together when desired. Locking the extension arms 34, 36 together is particularly advantageous for preventing damage to the extensometer 10 during handling, shipping, and the like. The locking assembly 140 may be considered a locking device. For example, with reference to FIGS. 2, 7, and 8, in one embodiment, the locking assembly 140 includes an elongated shaft 142 that extends through aligned openings provided in each of the extension arms 34 and 36. A movable locking member, illustrated here as a locking cam 144 for each extension arm 34, 36, selectively and releasably engages the corresponding extension arm 34, 36 and holds them together in a fixed position. The locking cams 144 are coupled together via a coupling member, here comprising the elongated shaft 142, thereby providing simultaneous locking of the extension arms 34, 36. A tactile indication is preferably provided when locking occurs. In the illustrated embodiment, at least one plunger 150 is provided for the fixed assembly 140, preferably including at least one plunger for each locking cam 144. Each plunger 150 includes a movable ball or protruding element that engages an opposing surface of each cam 144. A concave portion 145 (FIG. 2) may be provided on each of the cams 144 that is engaged by the protruding element(s) and may provide a tactile indication that the elongated shaft 142 and cam 144 are sufficiently positioned. In a particularly convenient form, each of the locking cams 144 is located within an opening 144A formed in each of the extension arms 34 and 36. This configuration protects the contact surface of the locking cam 144 from at least some environmental dust or contamination, and provides a convenient method for mounting the plunger 150 such that its protruding element protrudes into the opening 144A.

[0041] The stationary assembly 140 may further include an arm 151 between the extension arms 34, 36, the arm 151 having a first end rotatably coupled to the elongated shaft 142 and a second end connected and fixed to the flexure mounting block 80, specifically the link 100 joined therebetween as shown in FIG. 6. The central interconnect portion 95 may include an opening 92A to allow access to a mounting screw 152 for connecting the link 100 to the end of the arm 151. An opening 100A in the other link 100 is also provided to allow access to the screw 152. In the illustrated embodiment, the elongated shaft 142 of the stationary assembly 140 is supported by the arm 151, which in turn is connected to the force generating assembly 60. It should be noted that in another embodiment, the elongated shaft 142 may be supported by a stationary element such as found on the mounting assembly 14, such as the reaction block 68. When the cam 144 engages the plunger 150 the arms 34, 36 are fixed, whereas when the cam 144 is rotated to disengage the plunger 150 the arms 34, 36 are free to move.

[0042] The connecting member 76 with the pivot connection 78 to the extension arms 34, 36 helps to set or define the gage length of the extensometer in a repeatable manner with high accuracy, and avoids the need to use gage blocks or other techniques to ensure that the specimen engaging device 58 engages the specimen at the required spacing. In addition, the fixture assembly 140 holds the extension arms 34, 36 rigidly at the desired spacing until the specimen engaging device 58 can engage the specimen. After engagement occurs, the fixture assembly 140 can be operated to release the arms 34, 36. The arm 151 helps support the components of the fixture assembly 140 and serves as a reference device such that the arms 34, 36 are uniformly oriented relative to the connecting member 76, and in one preferred embodiment, the arms 34 and 36 are parallel to one another.

[0043] The coupling link 38 comprises another aspect of the present disclosure. In conventional connections of cross-flex assemblies, the cross-flex assemblies are arranged to be directly connected to the ends of the extension arms in a symmetrical manner to allow the extension arms to pivot relative to one another. However, when the coupling link 38 is present, the sensor assembly, now comprising a cross-flex assembly 160 of conventional design, is connected to one of the extension arms 34, 36, here as an example the extension arm 36.

[0044] A coupling link 38 is generally provided to ensure equal displacement of the extension arms 34, 36 when the ends of the sample engaging device connected to the specimen move toward and away from each other. In the embodiment illustrated in Figures 1, 2 and 4, the coupling link 38 comprises a bend having two generally spaced pivots that accompany the movement of the extension arms 34, 36. The length of the bend of the coupling link 38 is selected so that the pivots are approximately equal to the desired spacing of the extension arms, particularly the ends that engage the specimen. This construction helps minimize common mode errors when the extension arms 34, 36 move together in the same direction. In a particularly advantageous embodiment, the spacing between the pivots 78 formed between the connecting member 76 and the extension arms 34, 36 aids in repeatably setting the gage length for the extensometer relative to the specimen. Preferably, the spacing between the pivots 78 formed between the connecting member 76 and the extension arms 34, 36 is approximately equal to the spaced pivots formed in the bends 190.

[0045] In the embodiment shown in figures such as FIG. 4, a first portion 180 of the cross flexure 160 is connected to the lower extension arm 36 while a second portion 182 moves relative to the portion 180 with an orthogonally oriented flex element indicated at 184. While the first portion 180 is directly connected to one of the extension arms, the second portion 182 is not directly connected to the other extension arm, but rather through a connecting link 38 that extends preferably orthogonally to the axis of extension of the extension arms 34 and 36. In the embodiment shown, the connecting link 38 with a flexure 190 connected to the extension arm 34 with a connecting member 192 can be integrally formed as one unitary body with the extension arm 34 if desired. The other end of the connecting link 38 / flexure member 190 is fixedly attached to the second portion 182 of the cross flexure 160. It should be noted that preferably, one of the pivots formed in flexure member 190 (closest to the arm to which cross flexure 160 is attached) is collinear with the pivot axis of cross flexure 160 and the end of sample engagement device 58 to which extension arm 36 is attached. Flexure member 190 may be attached in any suitable manner, here using, by way of example, restraining blocks 196 and screws 198 to secure each of the ends of flexure 190 to portion 182 and connecting member 192.

[0046] As is conventionally known, the cross-flex assembly includes a first portion pivoting relative to a second portion with two flex elements oriented orthogonally to each other in a non-contact manner. In some embodiments, strain sensor gauges, not shown, are provided in the flexures forming the cross-flex assembly 160 to sense the movement of the portions 180, 182 relative to each other and thus the movement of the extension arms 34, 36. In other embodiments, other types of sensors sense the movement of the extension arms 34, 36. For example, sensors based on changes in capacitance, inductance or resistance may be used. Similarly, optically based sensors may be used if desired. Such sensing devices are well known. The aspects disclosed herein are not dependent on the type of sensor or sensing device used, and such will not be discussed further.

[0047] 7-9 illustrate other embodiments or features of the aspects described above, in which the same reference numbers are used for the same or similar components. First, the coupling link 38' illustrated in FIGS. 7-9 includes a rigid link 200 rather than a flexure 190 as described above. To provide compliance, the link 200 is preferably connected at a pivot connection, such as the pivot connection 78 with a cross flexure as described above. In this embodiment, the extension arm 34 is directly connected to the link 200. However, the connecting member 192 in the previous embodiment is substantially part of the extension arm 34 and is rigidly connected to the extension arm 34.

[0048] Generally, a coupling link 38' is provided to ensure equal displacement of the extension arms 34, 36 as the ends of the sample engaging device connected to the specimen move towards and away from each other. In the embodiment illustrated in Figures 7 and 8, the coupling link 38' comprises a rigid link 200 having two generally spaced pivots 78 that accompany the movement of the extension arms 34, 36, the spaced pivots 78 being approximately equal to the desired spacing of the extension arms 34, 36, particularly the ends that engage the specimen. This construction helps minimize common mode errors of the extension arms 34, 36 moving together in the same direction. It should be noted that preferably, one of the pivots 78 (closest to the arm having the attached cross bend 160) is collinear with the pivot axis of the cross bend 160 and the end of the sample engaging device 58 to which the extension arm 36 is attached. Preferably, the spacing between the pivots 78 formed between the connecting members 76 and the extension arms 34, 36 is approximately equal to the spacing of the pivots 78 formed in the links 78.

[0049] 3 illustrates yet another embodiment of the coupling link 38''. In this embodiment, two connecting links 201A and 201B are pivotally connected, here at pivots 78, with connecting link 201A to the end of extension arm 34 and connecting link 201B to the end of extension arm 36. A cross-flex assembly 160 is connected in series to the ends of connecting links 201A, 201B remote from the connections to extension arms 34, 36. The spacing of pivots 78 is approximately equal to the spacing of sample engaging devices attached to extension arms 34, 36.

[0050] As explained above, through the actuation device 70, the user can change the amount of contact force on the specimen through the force generating assembly 60. However, if the user wants to repeatedly apply the same force, for example to multiple specimens tested at different times, it can be difficult through rotation of the actuation device 70, since the force depends on the total amount of rotation. In Figs. 7-10, the force generating assembly 60 includes an actuation device 70' having a driver 202 to control the displacement of the control arm 66 relative to the reaction block 68 in a repeatable manner. Generally, the driver 202 includes a movable member 204 that contacts the end of the control arm 66. In one embodiment, the movable member 204 is a plate that slides on a guide 206, here formed in the reaction block 68. The movable member 204 has a width that varies along its length, and the movable member 204 and guide 206 are configured such that contact of the movable member 204 with the end of the control arm 66 displaces the control arm 66 as a function of the width of the portion of the movable member 204 that contacts the end of the control arm 66. Although not required, in one embodiment the guide 206 is configured to provide a guide path for the movable member 204 perpendicular to the axis of extension of the control arm 66 such that the displacement of the control arm 66 depends only on the width of the portion of the movable member 204 that contacts the movable member 204.

[0051] 10, the driver 202 includes a user-gripable member, such as a knob 208 having an indicator 210 attached thereto. The indicator 210 moves with the movable member 204 relative to a scale 212 provided on the reaction block 68. Using the knob 208, a user can slide the movable member 204 and the indicator 210 to a selected position on the scale 212. If desired, the knob 208 can be rotated such that the knob 208 frictionally engages and is secured to the reaction block 68 at the selected position.

[0052] In this regard, it should be noted that the inclination angle 203 (see, e.g., FIG. 9 ) of the contact between the end of the control arm 66 and the movable member 204 may be adjusted to provide a desired range of forces to be generated by the force generating assembly 60. The inclination angle 203 may be referenced from a reference axis 203A that is parallel to the path of guided motion of the movable member 204. Generally, a larger inclination angle 203 provides a larger range of forces that can be generated. A smaller inclination angle 203 may have a smaller range of forces that can be generated, but with a higher resolution. Although the inclination angle 203 is constant in the illustrated embodiment, this should not be considered limiting in that the shape of the surface of the movable member 204 that contacts the control arm 66 need not be flat as shown, but may vary, thus providing a varying inclination angle 203 depending on where the end of the control arm 66 contacts the movable member 204.

[0053] If desired, a tactile indication may be provided to a user as a function of the movable member 204 being in a preselected position that corresponds to at least some of the positions indicated by the scale 212. With reference to FIGS. 8 and 9, a detent mechanism selectively engages an area to provide a tactile indication. In the illustrated embodiment, the detent mechanism comprises a plunger 220 that selectively engages an opening or recess 224. In the exemplary embodiment, the plunger 220 is affixed to the reaction block 68 at a fixed position and the movable member 204 includes the opening or recess 224. However, in another embodiment, the plunger 220 moves with the movable member 204 and an opening or recess may be provided in the reaction block 68.

[0054] 11-13 illustrate another embodiment of the extensometer having some variations of the described lateral features, with the same reference numbers being used for the same or similar components. In particular, FIGS. 11-13 illustrate an arm locking assembly 140' that selectively locks the extension arms 34 and 36 together when desired. As indicated above, locking the extension arms 34, 36 together is particularly advantageous for preventing damage to the extensometer during handling, shipping, and the like. Similar to the locking assembly 140, the locking assembly 140' may be considered a locking device having a movable locking member, which in this embodiment is a locking plate 144' that selectively releasably engages portions of each of the extension arms 34 and 36. As illustrated, the locking plate 144' here includes a notch or recess 147A that receives the portion of the arm 34 that includes the pin 149A, and a notch or recess 147B that receives the portion of the arm 36 that includes the pin 149B. In this embodiment, arm 34 includes an opening 153A in which pin 149A is disposed, and arm 36 includes an opening 153B in which pin 149B is disposed. Openings 153A and 153B are also sized to receive locking plate 144' and allow relative movement therein. Locking plate 144' is supported by control arm 66'. Similar to control arm 66 described above, control arm 66' is coupled to force generating assembly 60 and is movable through an actuation device, represented in FIG. 11 as double arrow 159, which may comprise elements similar or functionally equivalent to actuation devices 70, 70'. Similar to control arm 66, control arm 66' moves sample engagement device 58 to contact a specimen (not shown) when displaced toward the specimen. Continued displacement of the control arm 66 ′ after contact of the sample engaging device 58 with the specimen then stores spring energy within the force generating assembly 60 .However, in this embodiment, because the locking plate 144' is coupled to the control arm 66', movement of the control arm 66' also moves the locking plate 144' relative to the extension arms 34, 36, and in particular the pins 149A, 149B, which causes the pins 149A, 149B to exit the notches 147A, 147B, releasing the arms 34, 36 from the locking plate 144' and allowing the arms 34, 36 to move freely. Thus, in this embodiment, the securing assembly 140' automatically releases or holds the arms 34, 36 with movement of the control arm 66' without requiring a separate step of unlocking or locking the securing assembly as is performed with the securing assembly 140. It should be noted that, if desired, the locking plate 144' can be configured to extend alongside the outer surfaces of the extension arms 34 and 36, rather than within the openings 153A, 153B. It should also be noted that, if desired, the locking plate 144' can be joined to the control arm 66' so as to be linearly slidable on and / or pivotally connected to the control arm 66' so as to be selectively movable relative to the control arm 66', e.g., if it is desired to have a separate action or step in addition to or instead of moving the control arm 66' to unlock or lock the locking plate 144' with the extension arms 34, 36.

[0055] The embodiment of Figures 11-13 also shows that a coupling assembly 62' having a variation of a connecting member 76' couples the flexure member 88 to the extension arms 34 and 36. In this embodiment, the connecting member 76' is not H-shaped, but rather is rectangular with an opening 76A' through which both extension arms 34 and 36 extend. A pivot connection 78 pivotally connects the connecting member 76' to each of the arms 34 and 36 and connects the connecting member 76' to the force generating assembly 60 at a flexure mounting block 80. However, in this embodiment, a single link 100' joins together the flexure mounting blocks 80 on each side of the force generating assembly 60.

[0056] Similar to the fixture assembly 140, the fixture assembly 140' holds the extending arms 34, 36 rigidly at the desired spacing until the sample engagement device 58 can engage the specimen. After engagement occurs, the fixture assembly 140' is effectively operated to release the arms 34, 36. The locking plate 144' having notches 147A, 147B helps support its role as a reference device so that the arms 34, 36 are uniformly oriented relative to the connecting member 76', and in one preferred embodiment, the arms 34 and 36 are parallel to one another.

[0057] When the specimen is in the environmental chamber, it is often desirable to use an extensometer to make measurements on the specimen. Figures 14 and 15 illustrate other aspects of an extensometer (such as extensometer 10 described above and illustrated again by way of example in Figures 14 and 15) that allow the extensometer to be advantageously used in an environmental test chamber. A cooling assembly or system 240 is provided to cool the mountings 44, 46 and the ends of the extension arms 34 and 36 closest to the mountings 44, 46. As illustrated, each of the mountings 44, 46 and the ends of the extension arms 34, 36 are provided with cooling passages, embodied herein as cooling tubes 244, 245, 246 and 247. In one embodiment, the cooling passages or tubes 244-247 are configured to extend transversely through the mountings 44, 46 and the ends and extension arms 34, 36 relative to the axis of extension of the elongated arms 34, 36. Fluid cooling lines, generally designated 250, fluidly couple the inlet port 252 and the outlet port 254 to the cooling tubes 244-247. In the illustrated embodiment, a first cooling line 256A connects the inlet port 252 to the cooling tube 244. A second cooling line 256B fluidly couples the cooling tube 244 to the cooling tube 245. A third cooling line 256C fluidly connects the cooling tube 245 to the cooling tube 246. A fourth cooling line 256D fluidly connects the cooling tube 246D to the cooling tube 247. A fifth cooling line 256E connects the cooling tube 247 to the outlet port 254. In the illustrated embodiment, the coldest cooling fluid is provided first to the cooling tubes 244 and 245 in the fittings 44, 46 because the fittings 44, 46 are closest to the heat of the environmental chamber. 15 should not be considered limiting, in that the cooling tubes may receive cooling fluid in any convenient manner. In the illustrated embodiment, the cooling tubes 244-247 are connected in series. However, if desired, the cooling tubes 244-247 may be configured with a cooling line that effectively provides cooling fluid to each of the cooling tubes 244-247 simultaneously, i.e., the cooling tubes 244-247 are fluidly connected in parallel.

[0058] 15, a heat dissipation shield 264 is bonded to the mounting portion 44 and a heat dissipation shield 266 is bonded to the mounting portion 46. The shields 264, 266 protect the mounting portions 44, 46 and other components of the extensometer 10 from the heat dissipation of the environmental chamber. However, in this embodiment, the shields 264, 266 also function as counterweights on each of the extension arms 34, 36 to offset at least some of the mass present on each arm 34, 36 on the other side of the connecting member 76 to which the arms 34, 36 are pivotally connected. In a preferred embodiment, the mass of each of the counterweights 264, 266 is selected to substantially approximate most, if not all, of the mass present on each arm 34, 36 to which the respective counterweight is attached. In this manner, the counterweights 264, 266 may pivotally neutralize the arms 34, 36 and make the extensometer more sensitive. When a flexion assembly, such as but not limited to a cross flexion assembly, is connected to the arms 34, 36 on the side of the connecting member 76 opposite the counterweights 264, 266, the amount of flexion in the flexion assembly is minimized if the counterweights 264, 266 are present and approximate the mass of each arm 34, 36 on the other side of the connecting member 76. Similarly, if non-contact sensing devices, such as capacitive or optical sensors, are used in the arms 34, 36 on the other side of the connecting member 76, the counterweights 264, 266 can be configured to offset the mass of these components. The counterweights 264, 266 can be secured to the corresponding mountings 44, 46 with suitable fasteners, such as threaded screws, not shown.

[0059] In the illustrated embodiment, the sample engagement device 58 extends through an associated opening 272 provided in each of the counterweights 264, 266. Such an arrangement in which the sample engagement device extends through the opening 272 is particularly convenient when the counterweights 264, 266 also function as heat shields. However, if such a function is not required, the counterweights 264, 266 may be of any other convenient shape. When the counterweights 264, 266 function as heat shields, each of the counterweights 264, 266 preferably includes extending flanges 264A, 266A that overlap each other in a spaced apart relationship when the counterweights 264, 266 are attached to the mountings 44, 46. In this manner, heat dissipation from the environmental chamber is blocked by the overlapping flanges 264A, 266A. In one embodiment, surfaces that face or are otherwise exposed to the radiant heat energy, such as surfaces 264B, 266B, are polished or otherwise reflective to reflect the radiant heat energy away from the counterweights 264, 266.

[0060] Although the subject matter has been described in terms of structural features and / or methodological acts, it should be understood that the subject matter defined in the appended claims, as has been held by the courts, need not be limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as exemplary forms of implementing the claims.

Claims

1. An extensometer structure, comprising: a mounting assembly having a first mounting block movable relative to a second mounting block; an extensometer structure bonded to the second mounting block, the extensometer structure comprising: A first extending arm; a second extension arm movably connected to the first extension arm; an extensometer structure comprising: a force generating assembly coupled to the extensometer structure by a spring element for biasing the extension arm toward a specimen; Equipped with The force generating assembly includes a connecting member pivotally connected to each of the extension arms, the spring element being connected to the connecting member.

2. The extensometer structure of claim 1, wherein the force generating assembly includes a control element, the spring element joins the extensometer structure to the control element, and the control element is movable relative to a stationary member.

3. The extensometer structure of claim 2, further comprising a user-adjustable driver connected to the control element for adjusting a position of the control element relative to the stationary member.

4. The extensometer structure of claim 3, wherein the user-adjustable driver comprises a rotatable threaded member configured to adjust the position of the control element relative to the stationary member.

5. The extensometer structure of claim 4, wherein the user-adjustable driver comprises a movable block that slidably engages the control element.

6. The extensometer structure of claim 5, wherein the movable block is slidable within the stationary member.

7. An extensometer structure as described in claim 6, wherein the movable block has a variable width between a sliding engagement portion with the control element and the stationary member.

8. An extensometer structure as described in any one of claims 6 to 7, wherein the movable block is movable relative to the stationary member to any one of a plurality of repeatable positions.

9. An extensometer structure as described in any one of claims 1 to 8, wherein the connecting member comprises an H-shaped member having an upper free end pivotally connected to the first extension arm and a lower free end pivotally connected to the second extension arm, the H-shaped member having a central portion positioned between the first and second extension arms.

10. The extensometer structure of claim 9, wherein the spring element comprises a first spring element on a first side of the extension arm and a second spring element on a second side of the extension arm.

11. The extensometer structure of claim 10, wherein the force generating assembly further comprises a movable mounting block pivotally connected to the connecting member, and each of the spring elements is joined to the movable mounting block.

12. The extensometer structure of claim 11, wherein each of the spring elements has a bend.

13. The extensometer structure of claim 11, wherein each of the spring elements has a pair of parallel bends.

Images