JP6406319B2 - Strength tester - Google Patents

Description

  The present invention relates to a strength tester that measures the bond strength of a metal plate test piece obtained by spot welding, for example, two metal plates.

  A method of spot welding is widely used for joining two metal plates in terms of ease of work, simplicity of configuration, and enhancement of joint strength. The strength test method by spot welding is established in Japanese Industrial Standard JISZ3136 ("Test Dimension and Test Method for Shear Test of Resistance Spot and Projection Welded Joint"), and among them, JISZ2241 ("Metal Material Tensile Test Method"). Describes the use of a tensile tester for material testing purposes.

  Tensile testing machines for the purpose of material testing are expensive and are mainly installed in research institutions and rarely installed at production sites. However, there are many voices from spot welding manufacturers who demand an inexpensive strength tester that can be used easily at the production site in terms of quality control.

  A conventional strength tester mainly uses a method of raising and lowering the elevating frame unit 501 with a ball screw 500 as shown in FIG. 12 (see, for example, Patent Document 1 or Patent Document 2). Further, a motor (not shown) is used as a drive source for raising and lowering the elevating frame unit 501 (see, for example, Patent Document 2). An upper chuck 502 is provided on the elevating frame portion 501, and a lower chuck 503 is provided on the lower portion of the casing so as to face the upper chuck 502. Both ends of the metal plate test piece 300 are gripped by the upper chuck 502 and the lower chuck 503.

  By the way, using a motor as a drive source for raising and lowering the elevating frame unit 501 increases the size of the device itself and increases the product cost, and is not suitable for installation on a production site. For this reason, the inventors of the present application have proposed a small and inexpensive strength tester using a manual hydraulic jack as a drive source in order to enable application at a production site (see Patent Document 3). Hereinafter, the strength tester proposed in the past by the inventors of the present application will be briefly described.

FIG. 13 is a front view showing the appearance of the strength tester 200 proposed by the inventors of the present application in the past, and FIG. 14 is a side view showing the appearance of the strength tester 200. 13 and 14, the strength tester 200 has a manual hydraulic jack 202 as a drive source for raising and lowering the elevating frame unit 201. The hydraulic jack 202 is placed on the upper base 203 and is covered with a casing 204. The lifting frame 201 is connected to the ram 206 of the hydraulic jack 202 via connecting members 212A and 212B. The ram 206 is lifted by moving the operation lever 213 up and down, and the lift frame 201 is lifted along with the lift. Note that the operation lever 213, the hydraulic jack 202 has become separately, is mounted on a hydraulic jack key 202 during strength testing.

  The upper base 203 is supported by four columns 207 to 210 and a lower base plate 211. An upper chuck 215 is attached to the lower surface of the central part of the elevating frame part 201. The upper chuck 215 is a rectangular plate-shaped gripping tooth 2151 that is attached to the elevating frame portion 201 by a fixing member 214 (see FIG. 14), and is a rectangular plate that is about half the size of the gripping tooth 2151. The gripping teeth 2152 that are arranged opposite to each other, and two clamping screws 2153 and 2154 that push the gripping teeth 2152 toward the gripping teeth 2151 so that the gripping teeth 2151 and 2152 grip one end of the metal plate test piece 300 are provided. . Wave-like projections are formed on the opposing surfaces of the gripping teeth 2151 and 2152 so that the metal plate test piece 300 can be firmly held.

  Through holes (not shown) for inserting two clamping screws 2153 and 2154 are formed at both ends of the gripping teeth 2152 in the longitudinal direction. Similarly, the gripping tooth 2151 is also formed with screw holes (not shown) in which two fastening screws 2153 and 2154 are screwed at both ends in the longitudinal direction. The screw hole (not shown) of the gripping tooth 2151 and the through hole (not shown) of the gripping tooth 2152 are such that the two fastening screws 2153 and 2154 do not hit the metal plate test piece 300 and the gripping teeth 2151 and 2152 When they are combined, the respective centers are formed at the same position. By tightening each of the two tightening screws 2153 and 2154, the gripping tooth 2152 is pushed into the gripping tooth 2151 side, and grips one end of the metal plate test piece 300 together with the gripping tooth 2151.

  On the other hand, a lower chuck 216 is attached to a position facing the upper chuck 215 on the upper surface of the lower base 211. The lower chuck 216 has a rectangular plate-like gripping tooth 2161 attached to the upper surface of the lower base plate 211 by a fixing member 217 (see FIG. 14) and a rectangular plate shape about half the size of the gripping tooth 2161. A gripping tooth 2162 disposed opposite to the tooth 2161, and two clamping screws 2163 and 2164 for pushing the gripping tooth 2162 toward the gripping tooth 2161 so that the gripping teeth 2161 and 2162 grip the other end of the metal plate test piece 300 And having. Wave-like projections are formed on the surfaces of the gripping teeth 2161 and 2162 facing each other so that the metal plate test piece 300 can be firmly held.

  Through holes (not shown) for inserting the two fastening screws 2163 and 2164 are formed at both ends of the gripping tooth 2162 in the longitudinal direction. Further, screw holes (not shown) into which the two fastening screws 2163 and 2164 are screwed are formed at both end portions of the gripping tooth 2161 in the longitudinal direction. The screw hole (not shown) of the gripping tooth 2161 and the through-hole (not shown) of the gripping tooth 2162 are such that the two fastening screws 2163 and 2164 do not hit the metal plate test piece 300, and the gripping teeth 2161 and 2162 When they are combined, the respective centers are formed at the same position. By tightening each of the two tightening screws 2163 and 2164, the gripping tooth 2162 is pushed into the gripping tooth 2161 side, and the other end of the metal plate test piece 300 is gripped together with the gripping tooth 2162.

  The hydraulic jack 202 is provided with a gauge hole (not shown) for displaying pressurization with a hydraulic gauge. A pressure converter 205 for converting the strength into an electric signal is installed in the gauge hole. As the pressure transducer 205, for example, a so-called load cell using a strain gauge is used. Since the load cell is generally expensive, it is of course possible to select a cheaper one within the required accuracy. The strength tester 200 includes a digital indicator 220 that digitally displays an electrical signal output from the pressure transducer 205, and a printer that is electrically connected to the digital indicator 220 and prints data input to the digital indicator 220. 221 is also included.

  After clamping the two clamping screws 2153 and 2154 of the upper chuck 215 and the two clamping screws 2163 and 2164 of the lower chuck 216 to grip both ends of the metal plate test piece 300, the operation lever 213 of the hydraulic jack 202 is operated. Is mounted on the apparatus main body and moved up and down, the ram 206 of the hydraulic jack 202 rises. As the ram 206 is raised, the elevating frame unit 201 connected to the upper chuck 215 is pushed upward, and a tensile force is applied to the metal plate test piece 300. The metal plate test piece 300 breaks when a tensile force exceeding the bonding force between the two metal plates is applied. The tension when the metal specimen 300 is broken is converted into a numerical value and displayed on the display 220. The tensile strength of the hydraulic jack 202 is converted into an electrical signal by the pressure converter 205 and displayed on the digital display 220 with a numerical value “kN”. The numerical value of the digital indicator 220 when the metal plate test piece 300 is broken is the maximum value of the strength of the metal plate test piece 300. This numerical value is printed by the printer 221 and remains as a record.

  In order to return the ram 206 of the hydraulic jack 202 to its original position, the release handle 218 for removing the oil that has entered the cylinder (not shown) of the hydraulic jack 202 is opened and the release valve (not shown) is loosened. By releasing a release valve (not shown), the hydraulic pressure of the hydraulic jack 202 is released, and the lifting frame 201 connected to the ram 206 is lowered. After the elevating frame portion 201 is lowered, the two clamping screws 2153 and 2154 of the upper chuck 215 and the two clamping screws 2163 and 2164 of the lower chuck 216 are loosened, and the broken metal plate test piece 300 is removed. This completes the strength test.

Japanese Patent Laid-Open No. 06-148047 JP 2003-344248 A JP 2010-151507 A

  However, the strength testing machine 200 proposed by the inventors of the present application in Patent Document 3 has the following problems. That is, each of the upper chuck 215 and the lower chuck 216 for gripping both ends of the metal plate test piece 300 composed of two metal plates joined by spot welding is provided with two clamping screws (that is, the upper chuck 215). In this case, the tightening screws 2153 and 2154 and the lower chuck 216 are tightened with the tightening screws 2163 and 2164), so that these tightening screws 2153, 2154, 2163, and 2164 can be uniformly tightened. It is difficult, and sufficient holding power cannot be obtained if it can be tightened.

  Further, in this strength tester 200, since the four fastening screws 2153, 2154, 2163, and 2164 are fastened, man-hours are required and workability is not good.

Incidentally, as a conventional strength tester capable of obtaining a stable holding force, for example, there is one described in JP-A-6-148047. This tensile tester has a structure in which each of the upper chuck and the lower chuck is tapered, and the occlusal force increases as the metal plate test piece is pulled, but the upper and lower chucks are processed into a tapered shape. Has a problem that the product cost increases because high accuracy is required.

  In order to solve the above-described conventional problems, the present invention has a relatively simple structure in each of two upper and lower chucks for holding a metal plate test piece composed of two metal plates joined by spot welding. An object of the present invention is to provide a strength tester capable of easily and evenly clamping a metal plate test piece.

The strength tester according to the present invention includes a manual hydraulic jack placed on an upper base plate of a housing frame, and a spot-welded metal plate disposed below the hydraulic jack in the housing frame. An upper chuck for gripping one end of the test piece, and a lower chuck that is disposed opposite to and spaced below the upper chuck in the housing frame and grips the other end of the metal plate test piece. In the strength tester, the upper chuck has a rectangular plate shape, and an upper end portion in one direction is connected to the hydraulic jack side, and the lower end portion in the one direction is separated by the same distance from the center to the left and right. A first screw hole penetrating both surfaces in the plate thickness direction is formed in one of the two positions, and a second screw hole penetrating both surfaces in the plate thickness direction is formed in the other of the two positions. Said hydraulic by raising the jack ram It forms a square plate shape with the first gripping tooth pulled to the jack side, and is disposed to face the lower end side in the one direction of the first gripping tooth, and penetrates both sides in the plate thickness direction at the center. A third screw hole is formed, and a first through-hole having two different diameters is formed at a position where the axis coincides with the axis of the first screw hole of the first gripping tooth. And a first pressing plate in which a second through hole having two different diameters is formed at a position coinciding with the axis of the second screw hole of the first gripping tooth, and a rectangular plate shape. The first gripping tooth and the first pressing plate are disposed between the first screw hole and the first pressing plate and the first penetration hole of the first pressing plate. A fifth through hole penetrating both surfaces in the plate thickness direction is formed at a position coinciding with the axial center of each hole, and the axial center is the second of the first gripping teeth. A second gripping tooth in which a sixth through-hole penetrating both surfaces in the plate thickness direction is formed at a position coinciding with the axial center of each of the second through-holes of the screw hole and the first pressing plate; A first spacer inserted in the fifth through-hole of the second gripping tooth in a cylindrical shape whose length in the direction is longer than the plate thickness of the second gripping tooth, and an axial length Has a cylindrical shape longer than the plate thickness of the second gripping tooth, and a second spacer inserted into the sixth through-hole of the second gripping tooth, and a first of the first pressing plate A first connecting bolt that engages with the first screw hole of the first gripping tooth through the first spacer inserted into the fifth through hole of the second gripping tooth, Through the second spacer inserted into the second through hole of the first pressing plate and the sixth through hole of the second gripping tooth, the A second connecting bolt that is screwed into the second screw hole of the first gripping tooth, and the length of the screw is longer than the thickness of the first pressing plate; A first clamping screw that engages with a screw hole, and the lower chuck has a rectangular plate shape, and a lower end portion in one direction is connected to a lower base plate of the housing frame, and the one direction A sixth screw hole penetrating both sides in the plate thickness direction is formed in one of two positions that are the same distance from the center on the left and right sides, and both sides in the plate thickness direction are formed at the other of the two positions. A seventh screw hole penetrating the third gripping tooth is formed to form a rectangular plate shape, and is disposed opposite to the upper end portion in the one direction of the third gripping tooth, with a plate thickness at the center. An eighth screw hole penetrating both sides of the direction is formed, and the axis coincides with the axis of the sixth screw hole of the third gripping tooth A seventh through-hole having two different hole diameters is formed in the position, and the eighth center of the two different hole diameters is located at a position where the axis coincides with the axis of the seventh screw hole of the third gripping tooth. The second pressing plate having a through hole and a square plate shape are disposed between the third gripping tooth and the second pressing plate, and an axis is formed of the third gripping tooth. An eleventh through hole penetrating both surfaces in the plate thickness direction is formed at a position coinciding with the respective axial centers of the sixth screw hole and the seventh through hole of the second pressing plate, and the axial center is the A twelfth through hole penetrating both surfaces in the plate thickness direction is formed at a position coinciding with the axis of each of the seventh screw hole of the third gripping tooth and the eighth through hole of the second pressing plate. A fourth gripping tooth having a cylindrical shape whose axial length is longer than the plate thickness of the fourth gripping tooth, and A third spacer inserted into one through-hole, and a cylindrical shape whose axial length is longer than the plate thickness of the fourth gripping tooth, and the twelfth through-hole of the fourth gripping tooth The third spacer inserted into the seventh spacer inserted into the eleventh through hole of the fourth spacer inserted into the seventh through hole of the second pressing plate and the fourth gripping tooth. The third connecting bolt screwed into the sixth screw hole of the gripping tooth, the seventh through hole of the second pressing plate, and the twelfth through hole of the fourth gripping tooth A fourth connecting bolt threadedly engaged with a seventh screw hole of the third gripping tooth through a fourth spacer; and a screw length longer than a thickness of the second pressing plate; A second clamping screw that is screwed into the eighth screw hole of the plate .

  According to the above configuration, each of the upper chuck and the lower chuck has two gripping teeth, one pressing plate, two spacers and two connecting bolts for connecting them, and one via the pressing plate. One clamping screw that pushes the gripping tooth into the other gripping tooth side, and tightens the two gripping teeth with one clamping screw in each of the upper chuck and the lower chuck. Each of the lower chucks does not reach one-side tightening. In this way, the metal plate test piece can be easily and evenly clamped with a relatively simple structure.

In the above configuration, in the upper chuck, the first pressing plate is located on both sides in the plate thickness direction at one of two positions on the center side with respect to the first and second through holes and at the same distance from the center. A third through hole having two different hole diameters penetrating through the second through hole is formed, and a fourth through hole having two different hole diameters penetrating both surfaces in the thickness direction is formed at the other of the two positions. A fourth screw hole extending in the thickness direction is formed in the second gripping tooth at a position coinciding with the axis of the third through hole of the first pressing plate, and the first pressing plate A fifth screw hole extending in the plate thickness direction is formed at a position coinciding with the axis of the fourth through hole of the fourth through hole, and the diameter is smaller than the small diameter portion of the third through hole of the first pressing plate. A larger first spring and a diameter smaller than a small diameter portion of the fourth through hole of the first pressing plate A state in which the first spring is inserted into the large-diameter portion having two different outer diameters consisting of a large second spring, a threaded small-diameter tip portion, and another large-diameter portion. And a first urging force adjusting screw inserted into the third through hole of the first pressing plate and the small-diameter tip portion screwed into the fourth screw hole of the second gripping tooth. , Having a two-stage different outer diameter consisting of a threaded small diameter tip portion and another large diameter portion, with the second spring inserted into the large diameter portion, A second urging force adjusting screw that is inserted into the fourth through hole of the pressing plate and in which the tip portion of the small diameter is screwed into the fifth screw hole of the second gripping tooth, The first and second urging force adjusting screws and the first and second springs are arranged with the second gripping teeth. It acts as a biasing means for biasing toward the first pressing plate side, and in the lower chuck, the second pressing plate has a center side from the seventh and eighth through holes and a right and left side from the center. A ninth through hole having two different diameters penetrating both sides in the plate thickness direction is formed at one of two positions separated by the same distance, and the other of the two positions passes through both sides in the plate thickness direction. A tenth through hole having a different diameter is formed, and the fourth gripping tooth extends in the thickness direction at a position coincident with the axis of the ninth through hole of the second pressing plate. A ninth screw hole is formed, and a tenth screw hole extending in the plate thickness direction is formed at a position coinciding with the axis of the tenth through hole of the second pressing plate, while the second screw plate A third spring having a larger diameter than the small diameter portion of the ninth through hole of the pressing plate, and the second pressing A fourth spring having a diameter larger than the small diameter portion of the tenth through-hole of the plate, a small-diameter tip portion that is threaded, and another large-diameter portion; With the third spring inserted into the large diameter portion, the ninth screw of the fourth gripping tooth is inserted into the ninth through hole of the second pressing plate, and the small diameter tip portion is the fourth gripping tooth. The third urging force adjusting screw that is screwed into the hole, a small-diameter tip portion that is threaded, and another large-diameter portion have two different outer diameters. In the state in which the spring is inserted, a fourth end is inserted into the tenth through hole of the second pressing plate and the small diameter tip portion is screwed into the tenth screw hole of the fourth gripping tooth. And the third and fourth biasing force adjusting screws and the third and fourth biasing force adjusting screws. Pulling acts as a biasing means for biasing said fourth gripping teeth on the second pressing plate side.

  According to the above configuration, in the upper chuck, as the first clamping screw is loosened, the second gripping tooth moves away from the first gripping tooth. Can be done in time. Similarly, in the lower chuck, as the second clamping screw is loosened, the fourth gripping tooth moves away from the third gripping tooth, so that the metal plate test piece can be easily attached and detached from the lower chuck in a short time. It can be carried out.

According to the present invention, in each of the upper and lower chucks for holding a metal plate test piece made of, for example, a metal plate joined by spot welding, the metal plate test piece can be easily and evenly provided with a relatively simple structure. Can be tightened.

The external appearance of the strength tester which concerns on one Embodiment of this invention is shown, (a) is a front view, (b) is a right view. The front view which expanded the part in which the upper side chuck | zipper and the lower side chuck | zipper in FIG. 1 were provided The right side view which expanded the part in which the upper side chuck | zipper and the lower side chuck | zipper in FIG. 1 were provided AA line sectional view of the upper chuck shown in FIG. FIG. 3 is a cross-sectional view taken along line AA of the upper chuck shown in FIG. 2, and shows a difference between when the first tightening bolt is not tightened and when it is tightened. Sectional view of the lower chuck shown in FIG. Sectional drawing which shows the 1st application example of the strength tester which concerns on one Embodiment of this invention. The 2nd application example of the strength tester which concerns on one Embodiment of this invention is shown, (a) is a side view, (b) is a top view The top view which shows the external appearance of the 1st clamping screw in a 2nd application example Sectional drawing which shows the assembly | attachment state of the 1st clamping screw and 2nd gripping tooth in a 2nd application example The top view which shows the characterizing part of the 3rd application example of the strength tester which concerns on one Embodiment of this invention. Front view showing the appearance of a conventional strength tester Front view showing the appearance of another conventional strength tester Side view showing the appearance of another conventional strength tester shown in FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described in detail with reference to the drawings.

  FIG. 1 shows an appearance of a strength tester 1 according to an embodiment of the present invention, where (a) is a front view and (b) is a right side view. FIG. 2 is an enlarged front view of a portion of the strength tester 1 where the upper chuck 3 and the lower chuck 4 are provided. FIG. 3 is an enlarged right side view of a portion where the upper chuck 3 and the lower chuck 4 of the strength tester 1 are provided. In FIG. 1 to FIG. 3, the same reference numerals are given to the portions common to FIG. 13 and FIG. 14 described above. In addition, in the strength tester 1 according to the present embodiment, most of the members constituting the strength tester 1 are made of metal, and unless otherwise specified, the fact that it is made of metal is not described.

  In FIG. 1 to FIG. 3, the upper chuck 3 of the strength tester 1 holds one end of a metal plate test piece 300 made up of two spot-welded metal plates, and the lower chuck 4 is a metal plate test piece 300. Grasp the other end of The upper chuck 3 is attached to the lower surface of the central part of the elevating frame part 201. The lower chuck 4 is attached to a position facing the upper chuck 3 on the upper surface of the lower base plate 211 provided below the four frames 207 to 210. The elevating frame unit 201 is connected to the ram 206 of the hydraulic jack 202 housed in the casing 204 via connecting members 212A and 212B, as in the conventional strength tester 200 shown in FIGS. The ram 206 of the hydraulic jack 202 rises when the operation lever 213 of the hydraulic jack 202 is attached and is moved up and down, and the lifting frame portion 201 rises along with this rise. After the ram 206 of the hydraulic jack 202 rises, the series handle 218 of the hydraulic jack 202 is opened to loosen the please valve (not shown), so that the ram 206 is gradually lowered to the original position and returned to the original position. When the test is performed again after the ram 206 is lowered to the original position, the series valve (not shown) is closed by tightening the series handle 218.

The upper chuck 3 is a rectangular plate-shaped first pressing tooth 31 having a rectangular plate-shaped first gripping tooth 31 attached to the lifting frame portion 201 by a fixing member 214 and screw holes penetrating both sides of the central portion. The plate 32, the first gripping tooth 31 and the first pressing plate 32 are arranged in parallel with a separation in the thickness direction, and one end of the first gripping tooth 31 and the first pressing plate 32. A first connecting bolt 33 that connects one of the ends, a second connecting bolt 34 that connects the other end of the first gripping tooth 31 and the other end of the first pressing plate 32; A rectangular plate shape that is substantially the same shape as one gripping tooth 31 is formed, and a through-hole ( fifth through-hole, not shown) into which the first connecting bolt 33 can be inserted is formed at one of both ends. other possible inserted second connecting bolt 34 through hole (sixth through hole of, not shown) Made is, the second gripping teeth 35 disposed between the first gripping tooth 31 and the first pressing plate 32, screw holes (third formed in the center portion of the first pressing plate 32 A first tightening screw 36 screwed into a screw hole (not shown). Wavy projections are formed on the surfaces of the first and second gripping teeth 31 and 35 facing each other so that the metal plate test piece 300 can be firmly held. Although the outer shapes of the first and second gripping teeth 31 and 35 and the first pressing plate 32 are rectangular, they may be square.

Two through-holes ( first and second screw holes, not shown) formed in the first gripping tooth 31 have screws and screws formed on the first and second connecting bolts 33 and 34, respectively. A mating screw is formed. Two through-holes ( first and second through-holes, not shown) formed in the first pressing plate 32 are a portion through which the cylindrical portions of the first and second connecting bolts 33 and 34 pass, 1 and two different diameter portions of the portion for accommodating the heads of the second connecting bolts 33 and 34. Two through holes formed in the first pressing plate 32 (the first, second through holes, not shown) in, in a portion cylindrical portion of the first, second connecting bolts 33, 34 pass, Screws are not formed.

  The upper chuck 3 has first and second urging members 37 and 38 arranged at equal intervals on both sides of the attachment position of the first clamping screw 36. The first urging member 37 is disposed on the inner side of the first connecting bolt 33 of the first pressing plate 32. The second urging member 38 is disposed on the inner side of the second connecting bolt 34 of the first pressing plate 32. The first and second urging members 37 and 38 constantly urge the second gripping teeth 35 toward the first pressing plate 32 side. Details of the first and second urging members 37 and 38 will be described later.

FIG. 4 is a cross-sectional view of the upper chuck 3 in FIG. As shown in the figure, the first and second gripping teeth 31 and 35 and the first pressing plate 32 are connected by first and second connecting bolts 33 and 34. A portion where the first spacer 50A is disposed between the first gripping tooth 31 and the first pressing plate 32 where the first connecting bolt 33 is disposed, and the second connecting bolt 34 is disposed. A second spacer 50 </ b> B is disposed between the first gripping teeth 31 and the first pressing plate 32. The first spacer 50 </ b> A has a cylindrical shape with both ends opened, and the inner diameter thereof is slightly larger than the outer diameter of the first connecting bolt 33, and the inner surface is flat. Further, as shown in the drawing, the length of the first spacer 50 </ b> A in the axial direction is longer than the plate thickness of the second gripping tooth 35. Similarly to the first spacer 50A, the second spacer 50B has a cylindrical shape with both ends opened, the inner diameter thereof is slightly larger than the outer diameter of the second connecting bolt 34, and the inner surface is flat. Further, as shown in the drawing, the length of the second spacer 50 </ b> B in the axial center direction is longer than the plate thickness of the second gripping teeth 35. The first and second gripping teeth 31 and 35 and the first pressing plate 32 are connected by first and second connecting bolts 33 and 34 via the first and second spacers 50A and 50B.

A through hole ( fifth through hole, not shown) through which the first spacer 50A can be inserted is formed in one of both ends of the second gripping tooth 35, and the second spacer 50B can be inserted into the other. A through hole ( sixth through hole, not shown) is formed. The second gripping tooth 35 can be moved between the first gripping tooth 31 and the first pressing plate 32 by the first and second spacers 50A and 50B. In addition, the shape of each of the first and second spacers 50A and 50B is not limited to a cylindrical shape. In short, any shape may be used as long as the second gripping teeth 35 can be supported movably and the first and second connection bolts 33 and 34 can be passed therethrough. For example, it may have a hexagonal cross section with both ends opened.

The first and second urging members 37 and 38 each include a screw (first urging force adjusting screw) 55 and a spring (spring) 56. The screw 55 is a screw having a different diameter in which the diameter of the cylindrical portion 55a is larger than the diameter of the screw portion 55b. The screw 55 is accommodated in a through hole (third through hole) 32 a formed in the first pressing plate 32 together with a spring (first spring) 56. The screw portion 55 b of the screw 55 is formed so as to be screwed into a screw hole (fourth screw hole) formed in the second gripping tooth 35. The through-hole 32a of the first pressing plate 32 has an opening on the side where the first urging member (biasing means) 37 is inserted slightly larger than the diameter of the spring 56 and faces the second gripping tooth 35. Is formed so as to be slightly larger than the diameter of the screw portion 55b of the screw 55. In the through hole (fourth through hole) 32 b of the first pressing plate 32, the opening on the side where the second urging member (urging means) 38 is inserted is larger than the diameter of the spring (second spring) 56. The opening on the side facing the second gripping tooth 35 is formed to be slightly larger than the diameter of the screw portion 55b of the screw (second urging force adjusting screw) 55. The opening diameter of the first pressing plate 32 on the side facing the second gripping teeth 35 of the through holes 32a , 32b is smaller than the opening diameter on the side where the first and second urging members 37, 38 are inserted. By forming, the spring 56 is prevented from coming off from the through holes 32a and 32b .

By inserting the screw 55 of the first urging member 37 into the through hole 32a of the first pressing plate 32 and screwing it in the state where the second gripping tooth 35 is in contact with the first pressing plate 32. The first biasing member 37 is fixed to the second gripping tooth 35. Similarly, the second urging member 38 is fixed to the second gripping tooth 35 by inserting and screwing the screw 55 of the second urging member 38 into the through hole 32 b of the first pressing plate 32. Is done. The first and second urging members 37 and 38 are configured so that some urging force is applied to the second gripping teeth 35 in a state where the second gripping teeth 35 are in contact with the first pressing plate 32. Is formed. Thus, the second gripping tooth 35 is constantly urged toward the first pressing plate 32 by the first and second urging members 37 and 38. Second gripping teeth 35, when the first clamping screw 36 is not tightened but in contact with the first pressing plate 32, in accordance with a first clamping screw 36 is tightened, gradually first The first gripping tooth 31 is approached away from the pressing plate 32.

  Since one end of the metal plate test piece 300 is inserted between the first and second gripping teeth 31 and 35 of the upper chuck 3, the first and second gripping teeth 31 are tightened by tightening the first tightening screw 36. 35, one end of the metal plate test piece 300 is gripped. When tightening the first tightening screw 36, the driver 240 shown in FIG. 1 or FIG. 2 is used.

  FIG. 5 is a cross-sectional view of the upper chuck 3 shown in FIG. 2 taken along line AA. When the first tightening screw 36 is not tightened (on the left side as viewed in the drawing) and when it is tightened (toward the drawing). FIG. 6 is a diagram showing the difference between the position of the second gripping tooth 35 in the right state) and the degree of contraction of the spring 56 of the first and second urging members 37 and 38. As shown in the figure, when the first tightening screw 36 is not tightened, the springs 56 of the first and second urging members 37 and 38 are in a state before they are fully extended. The second gripping teeth 35 are attracted to the first pressing plate 32 side by the urging force. By tightening the first tightening screw 36 from this state, the first tightening screw 36 advances toward the first gripping tooth 31 and comes into contact with the second gripping tooth 35. The tooth 35 is pushed out toward the first gripping tooth 31 side.

As the second gripping teeth 35 move toward the first gripping teeth 31, the springs 56 of the first and second urging members 37 and 38 are contracted, and the second gripping teeth 35 are moved. The restoring force for returning to the first pressing plate 32 side increases. The first fastening screw 36 is tightened until one end of the metal plate test piece 300 inserted between the first and second gripping teeth 31 and 35 is firmly held. When the first clamping screw 36 is loosened after gripping one end of the metal plate test piece 300, the second gripping teeth 35 are moved by the urging force of the first and second urging members 37, 38 accordingly. It is drawn back to the pressing plate 32 side. Then, it finally comes into contact with the first pressing plate 32.

  As described above, the upper chuck 3 has a structure in which the first and second gripping teeth 31 and 35 are tightened by the single first tightening screw 36. It can be gripped with a sufficient holding force without being tightened. Further, the upper chuck 3 has first and second urging members 37 and 38, which constantly urge the second gripping teeth 35 toward the first pressing plate 32, so that the upper chuck 3 3 can be easily attached and detached in a short time.

On the other hand, the lower chuck 4 is opposed to the upper chuck 3 so as to be spaced apart in the vertical direction and holds the other end of the metal plate test piece 300. 2 and 3, the lower chuck 4 has the same configuration as the upper chuck 3. That is, the lower chuck 4 has a rectangular plate-like third gripping tooth 41 fixed on the lower base plate 211 provided on the lower side of the four housing frames 207 to 210 and both sides of the central portion. A rectangular plate-shaped second pressing plate 42 in which a threaded hole is formed, and one of both ends of the third gripping tooth 41 and one of both ends of the second pressing plate 42 are inserted. A cylindrical third spacer (not shown) and a fourth cylindrical spacer inserted between the other end of the third gripping tooth 41 and the other end of the second pressing plate 42. (Not shown), a third connecting bolt 43 that connects one end of the third gripping tooth 41 and one end of the second pressing plate 42 through a third spacer (not shown), 4 through the spacer (not shown) of the other end of the third gripping tooth 41 and the second pressing plate 42. A fourth connecting bolts 44 for connecting the other end portion, a rectangular plate shape, a third screw hole which connecting bolts 43 are screwed in in one of the ends (6 screw holes, not shown) is formed A third gripping tooth 41 in which a screw hole (seventh screw hole, not shown) into which the fourth connecting bolt 44 is screwed is formed at the other end of both ends , the third gripping tooth 41 and the second gripping tooth 41 A second clamping screw that is screwed into a fourth gripping tooth 45 disposed between the pressing plate 42 and a screw hole (eighth screw hole) formed in the center of the second pressing plate 42. 46. The third and fourth spacers are the same as the first and second spacers 50A and 50B of the upper chuck 3.

The two through holes (sixth and seventh screw holes) formed in the third gripping tooth 41 are formed with screws that are screwed into the screw portions of the third and fourth connecting bolts 43 and 44. Yes. Two through holes (seventh through hole, eighth through hole, not shown) formed in the second pressing plate 42 are portions through which the cylindrical portions of the third and fourth connecting bolts 43 and 44 pass. And it consists of two different diameter parts of the part which accommodates the head of the 3rd, 4th connection bolt 43,44. Screws are not formed in the two through holes (seventh through hole and eighth through hole) of the second pressing plate 42. A through hole (an eleventh through hole, not shown) through which the third spacer can be inserted is formed in one of both end portions of the fourth gripping tooth 45, and a through hole through which the fourth spacer can be inserted into the other. (Twelfth through-hole, not shown) is formed. The fourth gripping teeth 45 can move between the third gripping teeth 41 and the second pressing plate 42 by third and fourth spacers (not shown).

The lower chuck 4 is arranged at equal intervals on both sides of the mounting position of the second tightening screw 46, and urges the fourth gripping teeth 45 toward the second pressing plate 42 side. Biasing members 47 and 48 are provided. The third urging member 47 is disposed inside the third connection bolt 43, and the fourth urging member 48 is disposed inside the fourth connection bolt 44. Although not shown, the fourth gripping teeth 45 are formed with screw holes into which the screws constituting the third and fourth urging members 47 and 48 are screwed. In this case, the screw hole into which the screw constituting the third biasing member 47 is screwed corresponds to the ninth screw hole, and the screw hole into which the screw constituting the fourth biasing member 48 is screwed is the tenth screw hole. It corresponds to the screw hole. Further, the screw constituting the third urging member 47 corresponds to the third urging force adjusting screw, and the screw constituting the fourth urging member 48 corresponds to the fourth urging force adjusting screw. The third and fourth urging members 47 and 48 correspond to urging means.

  Since the lower chuck 4 has the same configuration as that of the upper chuck 3, detailed description thereof is omitted. 2 is the same as the cross section taken along the line AA of the upper chuck 3, and therefore the cross section of the lower chuck 4 is omitted.

  As described above, the lower chuck 4 also has a structure in which the third and fourth biting teeth 41 and 45 are tightened by the single second tightening screw 46. Therefore, when the metal plate test piece 300 is gripped. Therefore, it is possible to grip with a sufficient holding force. Further, the lower chuck 4 also has third and fourth urging members 47 and 48, which constantly urge the fourth gripping teeth 45 toward the second pressing plate 42. The metal plate test piece 300 can be easily attached to and detached from the chuck 4 in a short time.

  The lower chuck 4 has a structure that can move back and forth in the thickness direction of the metal plate test piece 300 on the lower base plate 211. FIG. 6 is a cross-sectional view showing the structure of the lower chuck 4. In the figure, the lower chuck 4 includes two fixing brackets 225a and 225b each having an L-shaped cross section, and bolts for fixing the third gripping teeth 41 to these fixing brackets 225a and 225b. 226 and a nut 227, and a backing plate 228 for fixing the fixing brackets 225a and 225b to the lower base plate 211, and the fixing brackets 225a and 225b. And four bolts 229 for fixing to the lower base plate 211 together with the spacer 230. In the cross-sectional view of FIG. 6, only two of the four bolts 229 are visible, but there are actually four. In addition, since the spacers 230 are also provided for each of the four bolts 229, there are actually four spacers 230.

  The lower base plate 211 has four through-holes 211a extending in the thickness direction of the metal plate test piece 300 (in the direction of arrow C) (which does not look like an ellipse in the figure, but is actually the same). Individually formed. The four elliptical through-holes 211a are formed so that their centers coincide with the through-holes through which the bolts 229 of the fixing brackets 225a and 225b pass. The contact plate 228 has four screw holes (not shown) that are screwed into the four bolts 229. By passing a bolt 229 through each of the four through holes 211 a formed in the lower base plate 211 with a cylindrical spacer 230 interposed therebetween, each bolt 229 is screwed into a screw hole formed in the contact plate 228. The lower chuck 4 is fixed so as to be movable in the thickness direction (arrow C direction) of the metal plate test piece 300. The four bolts 229 are tightened to such an extent that the lower chuck 4 can be moved with a relatively small force.

The lower chuck 4 is usually positioned so that its axis coincides with the vertical axis of the upper chuck 3, but the thickness of each of the two metal plates constituting the metal plate test piece 300 increases. As a result, a deviation occurs in the axial center, and the metal plate test piece 300 is warped. When the metal plate test piece 300 is warped, shear stress is generated in addition to the normal stress, and this causes a decrease in accuracy in the strength test. On the other hand, by adopting a structure in which the lower chuck 4 can be moved back and forth in the thickness direction of the metal plate test piece 300, the thicknesses of the two metal plates constituting the metal plate test piece 300 are increased. However, when the metal plate test piece 300 is pulled, the lower chuck 4 moves in the direction of the arrow C by an amount corresponding to the increase in the thickness of each of the two metal plates. The board specimen 300 is not warped. This makes it possible to always perform a strength test with high accuracy.

  Thus, according to the strength tester 1 according to the present embodiment, the upper chuck 3 includes the first and second gripping teeth 31 and 35, the first pressing plate 32, and the two pieces that connect them. Spacers 50A, 50B and first and second connecting bolts 33, 34, and a first tightening screw 36 that pushes the second gripping teeth 35 toward the first gripping teeth 31 via the first pressing plate 32. The lower chuck 4 has third and fourth gripping teeth 41 and 45, a second pressing plate 42, two spacers (not shown) for connecting them, and third and fourth And the second clamping screw 46 that pushes the fourth gripping tooth 45 to the third gripping tooth 41 side through the second pressing plate 42. The gripping teeth 31 and 35 are tightened, and the gripping teeth on the lower chuck 4 Since 1 and 45 are tightened, each of the upper chuck 3 and the lower chuck 4 is not clamped, and the metal plate test piece 300 can be clamped easily and evenly with a relatively simple structure. Become. Further, since the number of parts of the tightening screw is reduced, the cost can be reduced and the number of work steps can be reduced.

  In addition, according to the strength tester 1 according to the present embodiment, the upper chuck 3 is configured such that the first gripping member 37 constantly biases the second gripping tooth 35 toward the first pressing plate 32. 38, and the lower chuck 4 has third and fourth urging members 47 and 48 that constantly urge the fourth gripping teeth 45 toward the second pressing plate 42, so that the upper chuck 3 and The metal plate test piece 300 can be easily attached and detached from each of the lower chucks 4 in a short time.

  Further, according to the strength testing machine 1 according to the present embodiment, the metal plate test piece 300 is configured because the lower chuck 4 has a structure that can be moved back and forth with respect to the thickness direction of the metal plate test piece 300. Even if the thickness of each of the two metal plates increases, the lower chuck 4 moves in such a way that the warp of the metal plate test piece 300 is eliminated when the metal plate test piece 300 is pulled in the strength test. It is possible to perform a strength test with accuracy.

  In the strength tester 1 according to the above embodiment, the upper chuck 3 is provided with the first and second urging members 37 and 38, and the lower chuck 4 is provided with the third and fourth urging members 47 and 48. However, it is not always necessary to provide these urging members 37, 38, 47, 48. If it is desired to further reduce the cost, these urging members 37, 38, 47, 48 may be omitted. I do not care. Even if the urging members 37, 38, 47, and 48 are omitted, the number of work steps can be reduced as compared with the case where two clamping screws are provided in each of the upper and lower chucks and the clamping is performed.

  Further, in the strength tester 1 according to the above embodiment, the lower chuck 4 has a structure that can move back and forth with respect to the thickness direction of the metal plate test piece 300, but the upper chuck 3 has the structure of the metal plate test piece 300. You may take the structure which can move back and forth with respect to the thickness direction. However, in order to make the upper chuck 3 movable, it is necessary to make all the mechanisms for lifting the upper chuck 3 movable.

Next, an application example of the strength tester 1 according to the above embodiment will be described.
(First application example)
In the strength tester 1 according to the embodiment, the first and second tightening screws 36 and 46 having a flat tip are used, and the tip surface of the first tightening screw 36 is attached to the second gripping tooth 35. The tip surface of the second clamping screw 46 is brought into contact with one surface of the fourth gripping tooth 45, but the tips of the first and second clamping screws 36, 46 are conical surfaces. At the same time, a conical hole into which the tip of the first clamping screw 36 is fitted is formed on one surface of the second gripping tooth 35 with which the first clamping screw 36 comes into contact, and the second clamping screw 46 comes into contact therewith. A conical hole into which the tip of the second clamping screw 46 is fitted may be formed on one surface of the fourth gripping tooth 45. In this way, the contact area between the first and second clamping screws 36 and 46 and the second and fourth gripping teeth 35 and 45 can be increased, and the first and second clamping screws 36 can be increased. 46, and the straightness of the first and second tightening screws 36, 46 is improved.

  FIG. 7 is a cross-sectional view showing a first application example of the strength tester 1 according to the embodiment. In the drawing, the first fastening screw 36A has a tip portion 36Aa having a conical surface. The second gripping tooth 35A has a conical hole 35Aa into which the tip portion 36Aa of the first clamping screw 36A is fitted. FIG. 7 shows the upper chuck 3. Similarly, in the lower chuck 4, the tip end portion of the second clamping screw 46 </ b> A has a conical surface, and the second gripping tooth 45 </ b> A has a second end. A conical hole is formed in the surface that comes into contact with the distal end surface of the tightening screw 46A.

  The first and second tightening screws 36 and 46 have a hemispherical shape in addition to a conical surface, and a hemispherical surface on the surface of the second gripping tooth 35 that contacts the front end surface of the first tightening screw 36. A hole having a shape may be formed, and a hemispherical hole may be formed on the surface of the fourth gripping tooth 45 that contacts the tip surface of the second clamping screw 46.

(Second application example)
In the strength tester 1 according to the above embodiment, the upper chuck 3 is provided with the first and second urging members 37 and 38, and the lower chuck 4 is provided with the third and fourth urging members 47 and 48. However, these urging members 37, 38, 47, 48 can be omitted. In the first place, for example, the first and second urging members 37 and 38 are arranged so that the second gripping tooth 35 is separated from the first gripping tooth 31 when the first tightening screw 36 is loosened. The test piece 300 is provided to facilitate removal from the upper chuck 3, and other means can of course be substituted if the same action is obtained. The same applies to the lower chuck 4.

  Here, since the upper chuck 3 and the lower chuck 4 have substantially the same structure, the upper chuck 3 will be described below as an example. FIGS. 8A and 8B are a side view and a plan view showing a second gripping tooth 35B of the second application example of the strength tester 1 according to the embodiment, wherein FIG. 8A is a side view and FIG. 8B is a plan view. . FIG. 9 is a side view showing the first fastening screw 36B of the second application example. FIG. 10 is a cross-sectional view showing an assembled state of the second gripping teeth 35B, the first pressing plate 32B, and the first clamping screw 36B of the second application example.

  As shown in FIG. 8, the second gripping teeth 35B of the upper chuck 3 are provided with through holes 35Bb and 35Bc for allowing the spacers 50A and 50B to pass therethrough and a first tightening screw 36B on the second gripping teeth 35B. Groove portions 35Bd for connection are formed. The groove part 35Bd is formed in a straight line shape extending from one end to the other end in the longitudinal direction of the second gripping tooth 35B and having a T-shaped cross section with a narrow opening (see FIG. 8A). In this case, the groove 35Bd is formed such that the center in the longitudinal direction thereof coincides with the center of the attachment position of the first clamping screw 36B (that is, the center of the through hole 32Ba of the first pressing plate 32B shown in FIG. 10). Has been.

  As shown in FIG. 9, the first tightening screw 36 </ b> B has a concave groove 36 </ b> Ba formed in the circumferential direction at the tip portion. The diameter of the portion where the groove portion 36Ba is formed is slightly smaller than the size of the opening portion of the groove portion 35Bd of the second gripping tooth 35B. By fitting the tip portion of the first clamping screw 36B into the groove portion 35Bd of the second gripping tooth 35B, the portion is locked to the opening portion of the groove portion 35Bd and connected to the second gripping tooth 35B. It becomes a state. Here, before the front end portion of the first clamping screw 36B is fitted into the groove 35Bd of the second gripping tooth 35B, the first clamping screw 36B is screwed into the through hole 32Ba of the first pressing plate 32B, This is performed in a state where the tip portion of the first fastening screw 36B ahead of the groove 36Ba is exposed from the surface on the opposite side of the first pressing plate 32B. That is, in FIG. 10, the first clamping screw 36B is screwed into the through hole 32Ba of the first pressing plate 32B, and the tip portion beyond the groove portion 36Ba is exposed from the opposite surface of the first pressing plate 32B. Thereafter, the tip end portion of the first clamping screw 36B is inserted into the groove 35Bd of the second gripping tooth 35B and brought to the center of the second gripping tooth 35B. Needless to say, the insertion of the distal end portion of the first clamping screw 36B into the groove portion 35Bd of the second gripping tooth 35B is performed at either end in the longitudinal direction of the groove portion 35Bd of the second gripping tooth 35B. Do it from one side. No screw is formed at the tip of the first tightening screw 36B, and the first clamping screw 36B idles in the groove 35Bd of the second gripping tooth 35B.

  After the first clamping screw 36B is assembled to the second gripping tooth 35B, the spacers 50A and 50B are inserted into the through holes 35Bb and 35Bc of the second gripping tooth 35B, and then the first and second connecting bolts 33 are inserted. , 34 are passed through the spacers 50A, 50B to connect the first gripping teeth 31 and the first pressing plate 32B.

  After assembling the upper chuck 3 in this manner, the first clamping screw 36B is tightened so that the tip abuts against the bottom surface of the groove 35Bd of the second gripping tooth 35B, and then the first clamping screw is further tightened. By tightening the screw 36B, the second gripping tooth 35B starts moving toward the first gripping tooth 31 side. In the tensile test, since the metal plate test piece 300 is inserted between the first and second gripping teeth 31 and 35B, the first and second gripping teeth 31 are further tightened by tightening the first tightening screw 36B. , 35B grips one end of the metal plate test piece 300. Similarly, the lower chuck 4 holds the other end of the metal plate test piece 300.

  After gripping both ends of the metal plate test piece 300 together with the lower chuck 4, the tensile test is started. After the tensile test is performed, the first clamping screw 36B is loosened in order to remove the metal plate test piece 300, but the tip portion of the first clamping screw 36B is in the groove 35Bd of the second gripping tooth 35B. Since the first clamping screw 36B is further loosened, the first clamping screw 36B pulls the second gripping tooth 35B, and the second gripping tooth 35B becomes the first gripping. Go away from tooth 31. As described above, the second gripping tooth 35B moves to the first gripping tooth 31 side by tightening the first tightening screw 36B, and loosens the first tightening screw 36B from the first gripping tooth 31. Leave.

  The groove 35Bd formed in the second gripping tooth 35B does not need to penetrate both ends in the longitudinal direction of the second gripping tooth 35B, and is the length to the vicinity of the mounting position of the first clamping screw 36B. It does not matter.

(Third application example)
FIG. 11 is a plan view showing a characteristic portion of a third application example of the strength tester 1 according to the embodiment. As shown in the figure, a hole 35Bf having a size and depth that allows the tip portion of the first clamping screw 36B to be inserted beyond the groove 36Ba at the position where the first clamping screw 36B of the second gripping tooth 35B is attached. And an inner space 35Bg having a size and depth capable of moving the tip portion ahead of the groove portion 36Ba of the first tightening screw 36B in the lateral direction (arrow E direction), and further forming a hole 35Bf By forming a hole 35Bh in the inner space 35Bg that allows only the groove 36Ba of the first tightening screw 36B to pass therethrough, the tip portion of the first tightening screw 36B is formed in the second gripping tooth 35B. It may be possible to lock. In FIG. 11, the through holes 35Bb and 35Bc for passing the spacers 50A and 50B are omitted.

  Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

  The present invention has an effect that a metal plate test piece composed of two metal plates joined by spot welding can be easily and uniformly clamped, and is a strength tester for measuring the bond strength of the metal plate test piece. Application to is possible.

DESCRIPTION OF SYMBOLS 1 Strength test machine 3 Upper chuck 4 Lower chuck 31 First gripping teeth 32, 32B First pressing plate
32a, 32b Through hole 32Ba Through hole 33 First connecting bolt 34 Second connecting bolt 35, 35B Second gripping teeth 35Bd, 36Ba Groove 35Bf, 35Bh Hole 35Bg Internal space 36, 36A, 36B First tightening screw 37 First biasing member 38 Second biasing member 41 Third gripping teeth 42 Second pressing plate 43 Third connection bolt 44 Fourth connection bolt 45 Fourth gripping teeth 46, 46A Second tightening Screw 47 Third biasing member 48 Fourth biasing member 50A First spacer 50B Second spacer 55 Screw 56 Spring 201 Lifting frame portion 202 Hydraulic jack 203 Upper base 204 Casing 205 Pressure transducer 206 Rams 207 to 210 Frame 211 Lower base plate 212A, 212B Connecting member 213 Operation Lever 214 Fixing member 218 Release handle 225a, 225b Fixing bracket 226, 229 Bolt 227 Nut 228 Contact plate 230 Spacer 240 Driver 300 Metal plate test piece

Claims (2)

A manual hydraulic jack placed on the upper base plate of the housing frame;
An upper chuck for gripping one end of a spot-welded metal plate specimen disposed below the hydraulic jack in the housing frame;
In the housing frame, a lower chuck that is disposed oppositely and spaced below the upper chuck and grips the other end of the metal plate test piece,
A strength testing machine comprising:
The upper chuck is
It forms a square plate, and the upper end side in one direction is connected to the hydraulic jack side, and the lower end side in the one direction has both sides in the plate thickness direction at one of two positions that are the same distance from the center to the left and right. A first screw hole penetrating the hydraulic jack is formed, and a second screw hole penetrating both sides in the plate thickness direction is formed at the other of the two positions, and is pulled toward the hydraulic jack by raising the ram of the hydraulic jack. A first gripping tooth,
A square plate is formed, and is arranged opposite to the lower end portion in the one direction of the first gripping tooth, and a third screw hole penetrating both surfaces in the plate thickness direction is formed at the center, and the shaft center is formed. A first through-hole having two different diameters is formed at a position coinciding with the axis of the first screw hole of the first gripping tooth, and the axis is the second of the first gripping tooth. A first pressing plate in which a second through hole having two different hole diameters is formed at a position coinciding with the axial center of the screw hole;
It forms a square plate shape and is arranged between the first gripping tooth and the first pressing plate, and the axial center is the first screw hole of the first gripping tooth and the first pressing plate. A fifth through-hole penetrating both surfaces in the plate thickness direction is formed at a position coinciding with the axis of each of the first through-holes, and the axis is the second screw hole of the first gripping tooth and A second gripping tooth in which a sixth through-hole penetrating both surfaces in the plate thickness direction is formed at a position coinciding with the axis of each of the second through-holes of the first pressing plate;
A first spacer having an axial length longer than the plate thickness of the second gripping tooth and inserted into the fifth through hole of the second gripping tooth;
A second spacer inserted in the sixth through hole of the second gripping tooth, having a cylindrical shape whose axial length is longer than the plate thickness of the second gripping tooth;
The first screw hole of the first gripping tooth and the screw through the first spacer inserted into the first through hole of the first pressing plate and the fifth through hole of the second gripping tooth. A first connecting bolt to be joined;
The second screw hole of the first gripping tooth and the screw through the second spacer inserted into the second through hole of the first pressing plate and the sixth through hole of the second gripping tooth. A second connecting bolt to be joined;
A first clamping screw having a screw length longer than a thickness of the first pressing plate and screwing into the third screw hole of the first pressing plate;
With
The lower chuck is
It has a square plate shape, the lower end side in one direction is connected to the lower base plate of the housing frame, and the upper end side in the one direction has a plate at one of two positions that are the same distance from the center left and right. A sixth screw hole penetrating both surfaces in the thickness direction is formed, a seventh screw hole penetrating both surfaces in the plate thickness direction is formed at the other of the two positions, and a third gripping tooth;
It has a square plate shape, is arranged to face the upper end portion in the one direction of the third gripping tooth, and has an eighth screw hole penetrating both sides in the plate thickness direction at the center. A seventh through hole having two different hole diameters is formed at a position coinciding with the axis of the sixth screw hole of the third gripping tooth, and the axis is the seventh through hole of the third gripping tooth. A second pressing plate in which an eighth through hole having two different hole diameters is formed at a position coinciding with the axial center of the screw hole;
It has a square plate shape and is arranged between the third gripping tooth and the second pressing plate, and the axial center is the sixth screw hole of the third gripping tooth and the second pressing plate. Eleventh through-holes penetrating both surfaces in the plate thickness direction are formed at positions corresponding to the respective axial centers of the seventh through-holes, and the axial center is the seventh screw hole of the third gripping tooth and A fourth gripping tooth in which a twelfth through hole penetrating both surfaces in the plate thickness direction is formed at a position coinciding with the axis of each of the eighth through holes of the second pressing plate;
A third spacer having an axial length longer than the plate thickness of the fourth gripping tooth and inserted into the eleventh through hole of the fourth gripping tooth;
A fourth spacer having an axial length longer than a plate thickness of the fourth gripping tooth and inserted into the twelfth through hole of the fourth gripping tooth;
The sixth screw hole of the third gripping tooth and the screw are passed through the third spacer inserted into the seventh through hole of the second pressing plate and the eleventh through hole of the fourth gripping tooth. A third connecting bolt to be joined;
The seventh screw hole of the third gripping tooth and the screw through the fourth spacer inserted into the seventh through hole of the second pressing plate and the twelfth through hole of the fourth gripping tooth. A fourth connecting bolt to be joined;
A second fastening screw having a screw length longer than the thickness of the second pressing plate and screwed into the eighth screw hole of the second pressing plate;
A strength tester. In the upper chuck,
The first pressing plate has two different hole diameters penetrating both surfaces in the plate thickness direction at one of two positions on the center side of the first and second through holes and at the same distance from the center. A third through hole is formed, and at the other of the two positions, a fourth through hole having two different diameters penetrating both surfaces in the plate thickness direction is formed. A fourth screw hole extending in the thickness direction is formed at a position coinciding with the axis of the third through hole of the first pressing plate, and an axis of the fourth through hole of the first pressing plate. While a fifth screw hole extending in the thickness direction is formed at a position coincident with the center,
A first spring having a larger diameter than the small diameter portion of the third through hole of the first pressing plate;
A second spring having a larger diameter than the small diameter portion of the fourth through hole of the first pressing plate;
The first pressing portion having a two-stage different outer diameter composed of a threaded small-diameter tip portion and another large-diameter portion, with the first spring inserted into the large-diameter portion. A first urging force adjusting screw that is inserted into the third through hole of the plate and in which the tip portion of the small diameter is screwed into the fourth screw hole of the second gripping tooth;
The first pressing member has a two-stage different outer diameter composed of a threaded small-diameter tip portion and another large-diameter portion, and the second spring is inserted into the large-diameter portion. A second urging force adjusting screw that is inserted into the fourth through hole of the plate and the tip portion of the small diameter is screwed into the fifth screw hole of the second gripping tooth;
Further comprising
The first and second biasing force adjusting screws and the first and second springs act as biasing means for biasing the second gripping teeth toward the first pressing plate,
In the lower chuck,
The second pressing plate has two different hole diameters penetrating both sides in the plate thickness direction at one of two positions on the center side of the seventh and eighth through holes and at the same distance from the center. A tenth through hole having two different diameters penetrating both sides in the thickness direction is formed at the other of the two positions, and the fourth gripping tooth has A ninth screw hole extending in the thickness direction is formed at a position coinciding with the axis of the ninth through hole of the second pressing plate, and the axis of the tenth through hole of the second pressing plate While a tenth screw hole extending in the thickness direction is formed at a position coincident with the center,
A third spring having a larger diameter than the small diameter portion of the ninth through hole of the second pressing plate;
A fourth spring having a larger diameter than the small diameter portion of the tenth through hole of the second pressing plate;
The second pressing portion has a two-stage different outer diameter composed of a threaded small diameter tip portion and another large diameter portion, and the third spring is inserted into the large diameter portion. A third biasing force adjusting screw that is inserted into the ninth through hole of the plate and the small-diameter tip portion is screwed into the ninth screw hole of the fourth gripping tooth;
The second pressing portion has a two-stage different outer diameter composed of a threaded small diameter tip portion and another large diameter portion, and the fourth spring is inserted into the large diameter portion. A fourth urging force adjusting screw inserted into the tenth through hole of the plate and having the tip portion of the small diameter screwed into the tenth screw hole of the fourth gripping tooth;
Further comprising
The third and fourth urging force adjusting screws and the third and fourth springs act as urging means for urging the fourth gripping teeth toward the second pressing plate. The strength tester described in 1.

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