CA1130605A - Extensometer for detecting traumatized ligaments - Google Patents
Extensometer for detecting traumatized ligamentsInfo
- Publication number
- CA1130605A CA1130605A CA342,608A CA342608A CA1130605A CA 1130605 A CA1130605 A CA 1130605A CA 342608 A CA342608 A CA 342608A CA 1130605 A CA1130605 A CA 1130605A
- Authority
- CA
- Canada
- Prior art keywords
- flexible
- elongatable
- ligament
- extensometer
- support base
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/45—For evaluating or diagnosing the musculoskeletal system or teeth
- A61B5/4533—Ligaments
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
- A61B5/107—Measuring physical dimensions, e.g. size of the entire body or parts thereof
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
- G01B7/18—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge using change in resistance
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/02—Details of sensors specially adapted for in-vivo measurements
- A61B2562/0261—Strain gauges
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
- A61B5/683—Means for maintaining contact with the body
- A61B5/6838—Clamps or clips
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/0089—Biorheological properties
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- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Physics & Mathematics (AREA)
- Medical Informatics (AREA)
- Surgery (AREA)
- Biophysics (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Dentistry (AREA)
- Molecular Biology (AREA)
- Oral & Maxillofacial Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Rehabilitation Therapy (AREA)
- Orthopedic Medicine & Surgery (AREA)
- Rheumatology (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
Abstract
EXTENSOMETER
Abstract of the Disclosure An extensometer for detecting traumatized ligaments where the elongation of the ligament is either abnormally large or abnormally small compared to the elongation measured on a healthy ligament for an angle of flexion of the knee. The extensometer comprises at least one flexible member having a strain gauge secured thereto to measure deflexion of the flexible member from its normal configuration. The flexible member has a free end and is secured at its opposed end to a support base. A clamping member is provided to retain the free end of the flexible member on a ligament whilst maintaining the support base sub-stantially stationary with respect to the ligament whereby elongation of the ligament is detected by the deformation of the flexible member from its initial configuration.
Abstract of the Disclosure An extensometer for detecting traumatized ligaments where the elongation of the ligament is either abnormally large or abnormally small compared to the elongation measured on a healthy ligament for an angle of flexion of the knee. The extensometer comprises at least one flexible member having a strain gauge secured thereto to measure deflexion of the flexible member from its normal configuration. The flexible member has a free end and is secured at its opposed end to a support base. A clamping member is provided to retain the free end of the flexible member on a ligament whilst maintaining the support base sub-stantially stationary with respect to the ligament whereby elongation of the ligament is detected by the deformation of the flexible member from its initial configuration.
Description
6~
BACKGROUND OF I~ TION
Field of the Invention ;:
Tne present invention relates to an extenso-meter Eor detecting traumatized ligaments.
Description of Prior Art The present techniques utilized to detect traumatized ligaments are imprecise and requlre open knee surgery to visually inspect the ligaments to determine if it is -traumatized, that is to say, if the ligament has been ruptured, elongated, etc. Of the apparatus known to measure deformation, these are too large to be utilized in measuring ligaments of the knee and a large number of these apparatus are not precise enough to make a proper measurement. Other known apparatus are so constructed t'nat their probes would damage the ligament if they were to attempt to use such apparatus on ligaments. Thus, with the deficiency in diagnostic apparatus Eor detecting traumatized ligaments, the technique utilized today by physicians is not precise and is often inadequate.
SUMMARY OF IMVENTION
It is a feature of the present invention to provide an extensometer for detecting traumatized ligaments which substantially overcomes all of the above mentioned disadvantages.
It is a further feature of the present invention to provide an extensometer for detecting traumatized ligaments which measures the elongation in ligaments when the ligaments are stretched, which stretching is effected by flexing the knee in the case of knee ligaments.
BACKGROUND OF I~ TION
Field of the Invention ;:
Tne present invention relates to an extenso-meter Eor detecting traumatized ligaments.
Description of Prior Art The present techniques utilized to detect traumatized ligaments are imprecise and requlre open knee surgery to visually inspect the ligaments to determine if it is -traumatized, that is to say, if the ligament has been ruptured, elongated, etc. Of the apparatus known to measure deformation, these are too large to be utilized in measuring ligaments of the knee and a large number of these apparatus are not precise enough to make a proper measurement. Other known apparatus are so constructed t'nat their probes would damage the ligament if they were to attempt to use such apparatus on ligaments. Thus, with the deficiency in diagnostic apparatus Eor detecting traumatized ligaments, the technique utilized today by physicians is not precise and is often inadequate.
SUMMARY OF IMVENTION
It is a feature of the present invention to provide an extensometer for detecting traumatized ligaments which substantially overcomes all of the above mentioned disadvantages.
It is a further feature of the present invention to provide an extensometer for detecting traumatized ligaments which measures the elongation in ligaments when the ligaments are stretched, which stretching is effected by flexing the knee in the case of knee ligaments.
- 2 - .
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A further feature of the present invention is to provide an extensometer which will give a precise measure of the elongation of the ligament between two given points.
A further feature of the present invention is to provide a method of detecting traumatized ligaments by means of an extensometer which will measure the elongation of a ligament when stretched.
Another feature of the present invention is to provide a method of detecting traumatized ligaments by means of an extensometer of a miniaturized type that may be used with an arthroscope.
According to the above features, from a broad aspect, the present invention provides an extensometer for detecting deformation of a biological elongatable member to be stretched. The extensometer comprises a support base and a pair of spaced-apart flexible plates. A strain gauge is secured to each of the flexible plates for measur-ing deflection of the flexible plates from their normal plane. The flexible plates each further comprise a free end and an opposed end, which opposed end is secured to the support base. The free end further comprises gripping means for engagement in a surface portion of the elongat-able member. Clamping means is provided for applying a force perpendicular to the elongatable member positioned opposite the gripping means of the pair of flexible plates to cause the gripping means to positively engage in the surface portion of the elongatable member. The clamping means is secured to the support base for maintaining the support base substantially stationary with respect to the elongatable member such that elongation of the elongatable member is detected by flexion of the flexible plates.
,,~
A further feature of the present invention is to provide an extensometer which will give a precise measure of the elongation of the ligament between two given points.
A further feature of the present invention is to provide a method of detecting traumatized ligaments by means of an extensometer which will measure the elongation of a ligament when stretched.
Another feature of the present invention is to provide a method of detecting traumatized ligaments by means of an extensometer of a miniaturized type that may be used with an arthroscope.
According to the above features, from a broad aspect, the present invention provides an extensometer for detecting deformation of a biological elongatable member to be stretched. The extensometer comprises a support base and a pair of spaced-apart flexible plates. A strain gauge is secured to each of the flexible plates for measur-ing deflection of the flexible plates from their normal plane. The flexible plates each further comprise a free end and an opposed end, which opposed end is secured to the support base. The free end further comprises gripping means for engagement in a surface portion of the elongat-able member. Clamping means is provided for applying a force perpendicular to the elongatable member positioned opposite the gripping means of the pair of flexible plates to cause the gripping means to positively engage in the surface portion of the elongatable member. The clamping means is secured to the support base for maintaining the support base substantially stationary with respect to the elongatable member such that elongation of the elongatable member is detected by flexion of the flexible plates.
- 3 -~L~3V6~5 According to a still further broad aspect of the present invention there is provided a method of detecting deformation of a biologically elongatable member utilizing a pair of spaced-apart flexible plates each including a strain gauge thereon, a free end with gripping means :Eor engagement in a surface portion of an elongatable member to be stretched, an opposed end secured to a support base, and a clamping means positioned opposite the gripping means. The method comprises the steps of clamping the free end of the flexible plates on the elongatable member with the clamping means by applying a force perpendlcular to the elongatable member to cause the gripping means to positively engage the surface portion of the elongatable member. The support base is retained substantially stationary with respect to the elongatable member. The elongatable member is stretched axially whereby the elongation of the elongatable member is detected by the flexion of the flexible plates from their normal plane.
Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description when considered in connection with the accompanying drawings in which like reference characters designate like or corresponding parts through the several views and wherein:
FIGURE 1 is a side view of the extensometer of the present invention, os FIGURE 2 is a side view of a flexible member of the extensometer showing the strain gauge;
FIGURE 3 is a side view of the extensometer showing its operation in measuring elongation in a stretched ligament, ~IGURE 4 is a perspective view of an extenso-meter designed in accordance with the invention;
FIGURE 5 is a side view of Figure 4;
FIGURE 6 is a perspective view of a further design of the extensometer of the invention; and .... , ...... :
FIGURES 7 and 8 are side views showing the manner in which a ligament is clamped against the flexible plates of the extensometer.
DESCRIPTION OF PREFERRED ~MBODIMENTS
Referring now to the drawings, and more parti-cularly to Figures 1 to 3, there is shown generally at 10, ; the extensometer of the present invention. The extenso-meter includes essentially two flexible plates or members 11 each having a strain gauge 12 secured thereto. The flexible plate 11 has a free end 13, for engagement with an elongatable member to detect elongation thereof. The .~ other or opposed end is a securable end h4 secured with a support base 15.
Referring more specifically to Figure 2, there is shown the construction of the strain.gauge 12 (well-. known in the art) and it consists of a fine wire 16 disposed in a serpentine path consisting of side-by-side parallel rows of wire with the longitudinal axis of each path 17 extending coaxially with the axis of flexion or the longitudinal axis 18 of the plate 11. As herein shown, the flexible plates are designed to adapt to ligaments and are formed with a narrow area in the area y~. - 5 -~3~6(~
of the serpentine path of the wire by cut-outs 19 in opposed longitudinal edges of the plate 11. The cut-ou-ts 19 make the plate more flexible in the strain gauge area.
The ends of the wire 16 terminate in terminals 20 for connection to suitable measuring apparatus or to elec-tronic circuit member (no-t shown) which provide an output signal representative of a change in resistance in the wire 16 by the fLexion of the plate.
The free end 13 of each plate 11 terminates in a gripping mechanism which is herein constituted by teeth-like protrusions 21 -formed by the cut-outs 22 in the lower edge of the plate 11. These teeth-like protrusions permit better gripping with the ligament and are termi-nated in blunt ends 23 to prevent damaging the ligament surface. The flexible plates 11 are very thin plates of miniature size. Of course, the free end 13 may have a different configuration to achieve the same results.
Figure 3 illustrates the operation of the - extensometer 10 and, as shown, clamping member 30, as - 20 will be described in detail later with respect to the embodiments of Figures 4 and 6, retain the free ends 13 of both flexible plates 11 against one side of a ligament 31 by applying a force in the direction of arrow 32, thus pushing the ligament transversely against the plates 11.
The clamping member 30 also maintains the support base 15 substantially stationary with respect to the ligament 31. When the ligament 31 is stretched from its ends in the directions of arrows 33, the elongation of the ligament 31 is detected by flexion of the flexible members 11, as illustrated by their phantom position 34. This deflecxion causes a change in the resistance of the strain gauge wire 16 and this is measured by electronic "
~L~3~ )5 circuit member, and in this case, by connecting the strain gauge in a Wheatstone bridge circuit (not shown) to give a signal representative of proper functioning of the ligament. It can be seen that if the ligament was severed, the force applied in the direction of arrows 33 would cause the ligament to move in both directions away from the rupture, that is to say, in both directions of the arrows 33. Depending on the location of the extenso-meter relative to the rupture, the flexible plates ll will flex abnormally away from each other if the rupture is between the plates. However, if the extensometer is positioned to one side of the rupture, the deformation of the plates will be negligible as there would be no deformation in that part of the ligament. In the case of a damaged but unsevered ligament, the flexion of the plates ll would result in an output signal, given by the electronic circuit member, correlated to represent the degree of severity of the injury.
Referring now to Figures 4 and 5, there is shown one embodiment of the construction of the extenso-meter. As herein shown, the device consists of a housing 40 into which the support base 15 is secured and a shield 41 surrounds the flexible plates 11 extending out of the housing 40. The hollow shield member 41 prevents damage to the ligament and permits the proper flexion of the plates ll. A cable 42 connects the strain gauges to a remote electronic circuit member (not shown). The circuit member could also conveniently be mounted in the housing 40.
- 1~3~6~5 As shown in Figures 4 and 5, the clamping member 30 lncludes a leaf spring 43 having a clamping portion 44 and a fixed end portion 45 secured within the housing 40. The clamping portion 44 is angulated and disposed adjacent the flexible members 11 to clamp a ligament onto the free end 13 of the flexible members with the pressure being applied transverse to the ligament by the force exerted by the spring 43.
Referring now to Figures 6 to 8, there is shown a further embodiment of the extensometer construc-tion. As herein shown, the clamping member 30 is constructed as a caliper clamp including opposed walls 50 hinged at a common end by a hinge connection 51.
; The walls 50 each are arcuately formed in a lower end to define a ligament receiving end 52 with opposed walls defining a mouth opening 53 between the free ends of the walls 50.
A spring-like member 55 is secured on the top end 56 of the support base 15 and extends between the top end 54 of the walls 50. By pressing the top ends 54 toward one another, the walls 50 will diverge away frorn one another, as shown in Figure 7, to open the mouth opening 53 to allow the ligament 31 to be grasped within the mouth and between the ligament receiving portions 52.
By releasing the top end of the opposed walls 50, the walls will come back to their original position by the biasing force of the member 55 against the top ends 54 of the walls 50, and squeeze the ligament 31 against the free end 13 of the flexible plates 11. There is insuffi-cient pressure in the clamp to cause the ligament 31 to elongate when it is stretched between its ends.
)5 Obviously, numerous modifications and varia-tions of the present invention are possible in light of the above teachings. It is therefore to be understood that withln the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. For example, it is conceivable that instead of having two flexible plates, there may be provided a single flexible plate 11 with the support base 15 being retained stationary with respect to the ligament by the clamping means. Also, the flexible member may be a plate or other flexible element having a detection mechanism capable of detecting the flexion thereof. Furthermore, the extensome-ter of the present invention may be used to measure elongation of other type de-Eormable members or membranes such as to measure skin deformation or to determine the elastomeric properties of tissue or cables constructed of extensible strands.
' .-
Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description when considered in connection with the accompanying drawings in which like reference characters designate like or corresponding parts through the several views and wherein:
FIGURE 1 is a side view of the extensometer of the present invention, os FIGURE 2 is a side view of a flexible member of the extensometer showing the strain gauge;
FIGURE 3 is a side view of the extensometer showing its operation in measuring elongation in a stretched ligament, ~IGURE 4 is a perspective view of an extenso-meter designed in accordance with the invention;
FIGURE 5 is a side view of Figure 4;
FIGURE 6 is a perspective view of a further design of the extensometer of the invention; and .... , ...... :
FIGURES 7 and 8 are side views showing the manner in which a ligament is clamped against the flexible plates of the extensometer.
DESCRIPTION OF PREFERRED ~MBODIMENTS
Referring now to the drawings, and more parti-cularly to Figures 1 to 3, there is shown generally at 10, ; the extensometer of the present invention. The extenso-meter includes essentially two flexible plates or members 11 each having a strain gauge 12 secured thereto. The flexible plate 11 has a free end 13, for engagement with an elongatable member to detect elongation thereof. The .~ other or opposed end is a securable end h4 secured with a support base 15.
Referring more specifically to Figure 2, there is shown the construction of the strain.gauge 12 (well-. known in the art) and it consists of a fine wire 16 disposed in a serpentine path consisting of side-by-side parallel rows of wire with the longitudinal axis of each path 17 extending coaxially with the axis of flexion or the longitudinal axis 18 of the plate 11. As herein shown, the flexible plates are designed to adapt to ligaments and are formed with a narrow area in the area y~. - 5 -~3~6(~
of the serpentine path of the wire by cut-outs 19 in opposed longitudinal edges of the plate 11. The cut-ou-ts 19 make the plate more flexible in the strain gauge area.
The ends of the wire 16 terminate in terminals 20 for connection to suitable measuring apparatus or to elec-tronic circuit member (no-t shown) which provide an output signal representative of a change in resistance in the wire 16 by the fLexion of the plate.
The free end 13 of each plate 11 terminates in a gripping mechanism which is herein constituted by teeth-like protrusions 21 -formed by the cut-outs 22 in the lower edge of the plate 11. These teeth-like protrusions permit better gripping with the ligament and are termi-nated in blunt ends 23 to prevent damaging the ligament surface. The flexible plates 11 are very thin plates of miniature size. Of course, the free end 13 may have a different configuration to achieve the same results.
Figure 3 illustrates the operation of the - extensometer 10 and, as shown, clamping member 30, as - 20 will be described in detail later with respect to the embodiments of Figures 4 and 6, retain the free ends 13 of both flexible plates 11 against one side of a ligament 31 by applying a force in the direction of arrow 32, thus pushing the ligament transversely against the plates 11.
The clamping member 30 also maintains the support base 15 substantially stationary with respect to the ligament 31. When the ligament 31 is stretched from its ends in the directions of arrows 33, the elongation of the ligament 31 is detected by flexion of the flexible members 11, as illustrated by their phantom position 34. This deflecxion causes a change in the resistance of the strain gauge wire 16 and this is measured by electronic "
~L~3~ )5 circuit member, and in this case, by connecting the strain gauge in a Wheatstone bridge circuit (not shown) to give a signal representative of proper functioning of the ligament. It can be seen that if the ligament was severed, the force applied in the direction of arrows 33 would cause the ligament to move in both directions away from the rupture, that is to say, in both directions of the arrows 33. Depending on the location of the extenso-meter relative to the rupture, the flexible plates ll will flex abnormally away from each other if the rupture is between the plates. However, if the extensometer is positioned to one side of the rupture, the deformation of the plates will be negligible as there would be no deformation in that part of the ligament. In the case of a damaged but unsevered ligament, the flexion of the plates ll would result in an output signal, given by the electronic circuit member, correlated to represent the degree of severity of the injury.
Referring now to Figures 4 and 5, there is shown one embodiment of the construction of the extenso-meter. As herein shown, the device consists of a housing 40 into which the support base 15 is secured and a shield 41 surrounds the flexible plates 11 extending out of the housing 40. The hollow shield member 41 prevents damage to the ligament and permits the proper flexion of the plates ll. A cable 42 connects the strain gauges to a remote electronic circuit member (not shown). The circuit member could also conveniently be mounted in the housing 40.
- 1~3~6~5 As shown in Figures 4 and 5, the clamping member 30 lncludes a leaf spring 43 having a clamping portion 44 and a fixed end portion 45 secured within the housing 40. The clamping portion 44 is angulated and disposed adjacent the flexible members 11 to clamp a ligament onto the free end 13 of the flexible members with the pressure being applied transverse to the ligament by the force exerted by the spring 43.
Referring now to Figures 6 to 8, there is shown a further embodiment of the extensometer construc-tion. As herein shown, the clamping member 30 is constructed as a caliper clamp including opposed walls 50 hinged at a common end by a hinge connection 51.
; The walls 50 each are arcuately formed in a lower end to define a ligament receiving end 52 with opposed walls defining a mouth opening 53 between the free ends of the walls 50.
A spring-like member 55 is secured on the top end 56 of the support base 15 and extends between the top end 54 of the walls 50. By pressing the top ends 54 toward one another, the walls 50 will diverge away frorn one another, as shown in Figure 7, to open the mouth opening 53 to allow the ligament 31 to be grasped within the mouth and between the ligament receiving portions 52.
By releasing the top end of the opposed walls 50, the walls will come back to their original position by the biasing force of the member 55 against the top ends 54 of the walls 50, and squeeze the ligament 31 against the free end 13 of the flexible plates 11. There is insuffi-cient pressure in the clamp to cause the ligament 31 to elongate when it is stretched between its ends.
)5 Obviously, numerous modifications and varia-tions of the present invention are possible in light of the above teachings. It is therefore to be understood that withln the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. For example, it is conceivable that instead of having two flexible plates, there may be provided a single flexible plate 11 with the support base 15 being retained stationary with respect to the ligament by the clamping means. Also, the flexible member may be a plate or other flexible element having a detection mechanism capable of detecting the flexion thereof. Furthermore, the extensome-ter of the present invention may be used to measure elongation of other type de-Eormable members or membranes such as to measure skin deformation or to determine the elastomeric properties of tissue or cables constructed of extensible strands.
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Claims (9)
1. An extensometer for detecting deformation of a biological elongatable member to be stretched, said extensometer comprising:
a support base;
a pair of spaced-apart flexible plates, a strain gauge secured to each of said flexible plates for measuring deflection of said flexible plates, from the normal plane of said flexible plates;
said flexible plates each further comprising a free end and an opposed end, said opposed end secured to said support base;
said free end further comprising gripping means for engagement in a surface portion of said elongatable member; and clamping means for applying a force perpendicular to said elongatable member positioned opposite said gripping means of said pair of flexible plates to cause said gripping means to positively engage in said surface portion of said elongatable member, said clamping means being secured to said support base for maintaining said support base substantially stationary with respect to said elongatable member such that elongation of said elongatable member is detected by flaxen of said flexible plates.
a support base;
a pair of spaced-apart flexible plates, a strain gauge secured to each of said flexible plates for measuring deflection of said flexible plates, from the normal plane of said flexible plates;
said flexible plates each further comprising a free end and an opposed end, said opposed end secured to said support base;
said free end further comprising gripping means for engagement in a surface portion of said elongatable member; and clamping means for applying a force perpendicular to said elongatable member positioned opposite said gripping means of said pair of flexible plates to cause said gripping means to positively engage in said surface portion of said elongatable member, said clamping means being secured to said support base for maintaining said support base substantially stationary with respect to said elongatable member such that elongation of said elongatable member is detected by flaxen of said flexible plates.
2. An extensometer as claimed in claim 1 wherein said biological elongatable member comprises a ligament.
3. An extensometer as claimed in claim 2 wherein said flexible plates comprise thin plates, said gripping means further comprising teeth-like protrusions formed in said free end of said plates.
4. An extensometer as claimed in claim 1, said flexible plates having at least one cut-out portion formed therein in the area of said strain gauge, said strain gauge comprising a wire forming a plurality of adjacent parallel paths with the longitudinal axis of each said paths of said wire extending coaxially with the axis of flexion of each said flexible plates.
5. An extensometer for detecting deformation for elongatable members, said extensometer comprising:
a support base;
at least one flexible member;
a strain gauge secured to said flexible member for measuring deflection of said flexible member from the normal configuration of said flexible member;
said flexible member comprising a free end and an opposed end, said opposed end being secured to said support base;
clamping means for retaining said free end of said flexible member on an elongatable member while maintaining said support base substantially stationary with respect to said elongatable member such that elonga-tion of said elongatable member is detected by flexion of said flexible member by the axial displacement thereof, and wherein said elongatable member comprises a ligament;
said at least one flexible member comprising a pair of spaced-apart flexible members; and said clamping means comprising a clamp member adapted to push a portion of said ligament against said free end of said flexible members.
a support base;
at least one flexible member;
a strain gauge secured to said flexible member for measuring deflection of said flexible member from the normal configuration of said flexible member;
said flexible member comprising a free end and an opposed end, said opposed end being secured to said support base;
clamping means for retaining said free end of said flexible member on an elongatable member while maintaining said support base substantially stationary with respect to said elongatable member such that elonga-tion of said elongatable member is detected by flexion of said flexible member by the axial displacement thereof, and wherein said elongatable member comprises a ligament;
said at least one flexible member comprising a pair of spaced-apart flexible members; and said clamping means comprising a clamp member adapted to push a portion of said ligament against said free end of said flexible members.
6. An extensometer as claimed in claim 5 wherein said clamp member further comprises a leaf spring having a clamping portion and a fixed end portion, said fixed end portion being immovably secured with respect to said support base, said clamping portion being disposed adja-cent said flexible member for clamping said ligament onto said free end of said members such that said ligament is disposed between said members and said clamping portion.
7. An extensometer as claimed in claim 5 said clamp member further comprising a caliper clamp having opposed walls hinged at a common end, an end for receiving said ligament comprising a free end of each said walls wherein each said ligament receiving end is disposed on a respective one of opposed sides of said flexible members below said free end of said members and spaced apart to include a mouth opening, said ligament receiving end being displaceable by said hinged common end to enlarge said mouth opening to restrain said ligament therethrough and transverse to said flexible members such that said elonga-tion may be detected.
8. A method of detecting deformation of a biologi-cally elongatable member utilizing a pair of spaced-apart flexible plates each including a strain gauge thereon, a free end with gripping means for engagement in a surface portion of an elongatable member to be stretched, an opposed end secured to a support base, and a clamping means positioned opposite said gripping means comprising the steps of:
clamping said free end of said flexible plates on said elongatable member with said clamping means by applying a force perpendicular to said elongatable member to cause said gripping means to positively engage said surface portion or said elongatable member, retaining said support base substantially stationary with respect to said elongatable member, stretching said elongatable member axially, and detecting elongation of said elongatable member by deflexion of said flexible plates from the normal plane of said flexible plates.
clamping said free end of said flexible plates on said elongatable member with said clamping means by applying a force perpendicular to said elongatable member to cause said gripping means to positively engage said surface portion or said elongatable member, retaining said support base substantially stationary with respect to said elongatable member, stretching said elongatable member axially, and detecting elongation of said elongatable member by deflexion of said flexible plates from the normal plane of said flexible plates.
9. An extensometer as claimed in claim 1 wherein said spaced-apart flexible plates are disposed on one side of said biological elongatable member.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA342,608A CA1130605A (en) | 1979-12-21 | 1979-12-21 | Extensometer for detecting traumatized ligaments |
| AU64630/80A AU6463080A (en) | 1979-12-21 | 1980-11-24 | Extensometer |
| GB8038279A GB2065886B (en) | 1979-12-21 | 1980-11-28 | Extensometer |
| DE19803047349 DE3047349A1 (en) | 1979-12-21 | 1980-12-16 | "EXTENSION MEASURING DEVICE AND METHOD FOR DETECTING MOLD CHANGES ON EXTENDABLE OBJECTS" |
| FR8026771A FR2472169A1 (en) | 1979-12-21 | 1980-12-17 | EXTENSOMETER AND METHOD FOR DETECTING THE DEFORMATION OF AN ELONGABLE ELEMENT |
| JP18029080A JPS56125603A (en) | 1979-12-21 | 1980-12-19 | Method of and tensometer for detecting deformation of stretchable member |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA342,608A CA1130605A (en) | 1979-12-21 | 1979-12-21 | Extensometer for detecting traumatized ligaments |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1130605A true CA1130605A (en) | 1982-08-31 |
Family
ID=4115905
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA342,608A Expired CA1130605A (en) | 1979-12-21 | 1979-12-21 | Extensometer for detecting traumatized ligaments |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS56125603A (en) |
| AU (1) | AU6463080A (en) |
| CA (1) | CA1130605A (en) |
| DE (1) | DE3047349A1 (en) |
| FR (1) | FR2472169A1 (en) |
| GB (1) | GB2065886B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3309122A1 (en) * | 1983-03-15 | 1984-09-20 | Mauser-Werke Oberndorf Gmbh, 7238 Oberndorf | PROBE HEAD FOR MEASURING DEVICES |
| EP0312761B1 (en) * | 1987-10-09 | 1992-03-04 | Marposs Societa' Per Azioni | Device for checking linear dimensions of parts |
| DE3808346A1 (en) * | 1988-03-12 | 1989-09-28 | Geesthacht Gkss Forschung | Displacement sensor (position pickup) |
| US5347871A (en) * | 1992-02-03 | 1994-09-20 | Teledyne Industries, Inc. | Strain sensor |
| RU2634487C1 (en) * | 2016-09-16 | 2017-10-31 | Акционерное общество "Иркутский научно-исследовательский и конструкторский институт химического и нефтяного машиностроения" (АО "ИркутскНИИхиммаш") | Dynamic deformation plated strain gauge |
| CN110346207B (en) * | 2019-04-19 | 2024-04-09 | 浙江省人民医院 | Anterior cruciate ligament biomechanical property measuring device |
| RU209311U1 (en) * | 2021-12-10 | 2022-03-15 | Общество с ограниченной ответственностью "АТМ АКРОНЕКС" | LOAD GAUGE |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2543429A (en) * | 1949-06-20 | 1951-02-27 | David S Wood | Extensometer |
| US2744181A (en) * | 1953-04-21 | 1956-05-01 | Boeing Co | Extensometers |
| US2917920A (en) * | 1955-09-22 | 1959-12-22 | Southern Res Inst | Apparatus for testing metals and test specimen for use therein |
| GB1573911A (en) * | 1976-01-08 | 1980-08-28 | Nat Res Dev | Medical instruments for estimation of cervical dilutation |
-
1979
- 1979-12-21 CA CA342,608A patent/CA1130605A/en not_active Expired
-
1980
- 1980-11-24 AU AU64630/80A patent/AU6463080A/en not_active Abandoned
- 1980-11-28 GB GB8038279A patent/GB2065886B/en not_active Expired
- 1980-12-16 DE DE19803047349 patent/DE3047349A1/en not_active Withdrawn
- 1980-12-17 FR FR8026771A patent/FR2472169A1/en active Pending
- 1980-12-19 JP JP18029080A patent/JPS56125603A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| AU6463080A (en) | 1981-07-02 |
| FR2472169A1 (en) | 1981-06-26 |
| DE3047349A1 (en) | 1981-09-17 |
| JPS56125603A (en) | 1981-10-02 |
| GB2065886A (en) | 1981-07-01 |
| GB2065886B (en) | 1984-08-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |