JP4164618B2 - Bending test equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bending test apparatus, and more particularly to a bending test apparatus suitable for performing a test with a relatively long span or a bending test of a test piece having a large amount of bending deflection.
[0002]
[Prior art]
In a bending test of a test piece, in general, two fulcrums are fixed at a position separated by a predetermined distance in the horizontal direction, and the lower surface of the test piece is supported by each fulcrum, and the test piece is placed between the two fulcrums. A bending load is applied to the test piece by pressing one punch in the case of three-point bending and two punches in the case of four-point bending.
[0003]
In the case where the test piece is, for example, plywood, a fulcrum steel plate with a flat surface abutting against the lower surface of the test piece is interposed between each fulcrum and the test piece, and the fulcrum steel plate is attached to each fulcrum. On the other hand, it is stipulated that the bending test is performed in a state where the test piece is always supported by a surface by supporting the test piece so as to be rotatable about an axis orthogonal to the separation direction of the two fulcrums.
[0004]
FIG. 7 shows a configuration example of a main part of a conventional bending test apparatus that performs such a bending test. FIG. 7 shows a case where a three-point bending test is performed. Two fulcrums 72a and 72b are attached to a fulcrum mounting base 71 fixed to an apparatus frame (not shown) so that the distance between them can be adjusted. Above this, a punch 73 mounted via a mounting boss 73a is disposed on a platen (not shown) that is displaced in the vertical direction by a vertical movement mechanism. And the fulcrum steel plates 74a and 74b are supported on the top of each fulcrum 72a and 72b, respectively. The top of each fulcrum 72a, 72b is an R surface having a ridge line in a direction orthogonal to the paper surface, that is, a direction orthogonal to the separation direction of the two fulcrum 72a, 72b, and each fulcrum steel plate 74a, 74b is on the R surface. In the mounted state, the fulcrum brackets 75a and 75b are loosely engaged with the fulcrums 72a and 72b so that the fulcrum brackets 75a and 75b prevent the fulcrum 72a and 72b from falling. Thus, the two fulcrums 72a and 72b are supported so as to be rotatable around a horizontal axis (axis in the ridge line direction of the R surface) orthogonal to the separation direction.
[0005]
In the test, the test piece W is placed on the two fulcrum steel plates 74a and 74b in a surface contact state, and the punch 73 is lowered in this state to apply a bending load. When the test piece W is bent by this bending load, the fulcrum steel plates 74a and 74b rotate (tilt) on the R surface of the fulcrum 72a and 72b, and the test piece W is in surface contact with the fulcrum steel plates 74a and 74b. It is designed to maintain a supported state.
[0006]
[Problems to be solved by the invention]
By the way, in the conventional bending test apparatus as described above, when the distance between the fulcrums 72a and 72b is relatively short, that is, in a test with a relatively short span, the bending deflection amount of the test piece W is relatively small. In this case, there is no particular problem. However, if the bending amount of the test piece W is large in a relatively long span test, the fulcrum steel plates 74a and 74b may be rotated following the bending of the test piece W. Further, it is inevitable that slip occurs between the fulcrum steel plates 74a and 74b and the test piece W, and there is a problem that the influence of the friction appears in the test result.
[0007]
The present invention has been made in view of such circumstances, and even when a long span test or a bending amount of the test piece is large, no slip occurs between the test piece and the fulcrum steel plate, and it is always accurate. The object is to provide a bending test apparatus capable of obtaining test results.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the bending test apparatus according to the present invention has two fulcrums arranged at positions separated from each other by a predetermined distance in the horizontal direction, and a test piece support surface on the upper surface of each fulcrum. A fulcrum steel plate is supported so as to be rotatable about a horizontal axis perpendicular to the separation direction of the two fulcrums, and one or two punches are provided above it so as to be movable in the vertical direction. In the state where the test piece is supported from the lower surface by the test piece support surface of each fulcrum steel plate, the one or two punches are pressed against the upper surface of the test piece, so that the test piece is subjected to a three-point or four-point bending test. In the bending test apparatus for performing the above, each fulcrum steel plate includes a lower member that is rotatably supported with respect to the fulcrum, and an upper member on which a test piece support surface that contacts the lower surface of the test piece is formed. The upper part is It characterized by being movably supported in the spacing direction of the two pivot relative to the lower member (claim 1).
[0009]
Here, in the present invention, when two punches are used to perform a four-point bending test on the test piece, each of the punches is separated from the vertical movement mechanism by the separation direction of the two fulcrums. A punch upper member supported rotatably about a horizontal axis orthogonal to the surface, a test piece pressing surface abutting against the upper surface of the test piece, and the two fulcrums with respect to the punch upper member It is desirable to have a structure having a punch lower member supported so as to be movable in the separation direction.
[0010]
The present invention is intended by providing each fulcrum steel plate in contact with and supporting the lower surface of the test piece with both a turning function around a horizontal axis perpendicular to the span direction and a function of moving in the span direction. It is intended to achieve the purpose.
[0011]
That is, the fulcrum steel plate is divided into an upper member having a test piece support surface that comes into contact with the test piece and a lower member that is rotatably supported with respect to the fulcrum, and the upper member is separated from the lower member. By supporting it so that it can move in the span direction, when the test piece is bent during a long span test or a bending test with a large bending deflection, the fulcrum steel plate rotates according to the bending angle of the test piece. The fulcrum steel plate moves according to the amount of support in the horizontal direction by the fulcrum steel plate due to the bending of the test piece, and no slip occurs at the contact position between the test piece surface and the fulcrum steel plate. It is possible to obtain a test result without the influence of friction.
[0012]
In addition, the two punches used in the four-point bending test are slipped between the test piece in the same manner as the fulcrum steel plate in the long span test or the bending test of the test piece having a large bending deflection. Will be included in the test results. Therefore, as in the invention according to claim 2, the two punches used for the four-point bending test are divided into a punch upper member and a punch lower member, respectively, and the fulcrum steel plate described above with respect to the vertical movement mechanism for the punch upper member. For the punch lower member that is supported so as to be rotatable around the horizontal axis in the same direction as the test piece and that has a test piece pressing surface that contacts the upper surface of the test piece, it is supported so as to be movable in the span direction with respect to the punch upper member. As a result, the punch rotates as a whole according to the bending angle of the test piece, and at the same time, the punch upper member moves according to the approaching amount of the pressing portion by the punch accompanying the bending of the test piece, and the test piece and the punch The occurrence of slipping at the contact position can be suppressed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view showing the overall configuration of the embodiment of the present invention, and FIG. 2A is a left side view showing the punch 9 omitted in order to avoid complication of the drawing. ) Is a left side view of the punch 9.
[0014]
A fulcrum mounting beam 3 is fixed to the portal frame 1 and the auxiliary frames 2a and 2b, and the distance (span) between the two fulcrum mounting bases 4a and 4b in the horizontal direction can be adjusted to the fulcrum mounting beam 3. Is provided. The fulcrum mounts 4a and 4b are fixed with fulcrums 5a and 5b, respectively, and each fulcrum 5a and 5b is formed in an R surface or wedge shape in which a top portion T described later has a ridge line in a direction perpendicular to the span direction. ing. And the fulcrum steel plates 6a and 6b are each provided in the top part of each fulcrum 5a and 5b so that rotation is possible around the axis | shaft along each ridgeline.
[0015]
The portal frame 1 supports a crosshead 7 to which a displacement in the vertical direction is applied by a load mechanism (not shown), and a punch mounting beam 8 is fixed to the crosshead 7. A three-point bending punch 9 is attached to the central portion of the punch attachment beam 8, and two four-point bending punches 10a and 10b are formed on both sides in the horizontal direction. The distance is adjustable.
[0016]
Now, the left and right fulcrums 5a and 5b and the fulcrum steel plates 6a and 6b have the same structure, respectively, and an enlarged front view and a right side view thereof are shown on the right side in FIGS. Show. The fulcrum steel plate 6a is divided into a lower member 61a whose lower surface is placed on the top T of the fulcrum 5a and an upper member 62a in which a support surface S for supporting the test piece W is formed on the upper surface, and the upper member 62a. Is supported so as to be movable in the span direction with respect to the lower member 61a.
[0017]
That is, the upper member 62a is supported by the lower member 61a via a plurality of stroke bearings 63a that allow only linear movement in the span direction, and the plurality of guide bars 64a extending in the same direction is supported on the lower member 61a. The upper member 62a can be moved in the span direction by the stroke bearing 63a while being guided by the guide bar 64a.
[0018]
As described above, the lower member 61a is restricted from moving in the same direction by the guide plates 65a disposed on both sides of the ridge line direction of the fulcrum 5a with its lower surface placed on the top T of the fulcrum 5a. Two tension coil springs 66a are interposed between each of the guide plates 65a on both sides and the lower member 61a. The total of four tension coil springs 66a pulls the lower member 61a to both sides in the span direction. It has been. Thereby, the lower member 61a is supported so as to be rotatable about the horizontal axis along the ridgeline of the fulcrum 5a orthogonal to the span direction with respect to the fulcrum 6a, and in the unloaded state, the support surface S of the upper member 6a. Is always elastically restricted so that its rotational position is substantially along the horizontal direction. The above configuration is exactly the same for the left fulcrum 5b and the fulcrum steel plate 6b.
[0019]
Next, the punches 9, 10a and 10b that move in the vertical direction to apply a bending load to the test piece W will be described. FIG. 5 is an enlarged front view of the main part in the vicinity of the punch mounting beam 8, and FIG. 6 is a left side view of the punch 10a.
[0020]
The three-point bending punch 9 is a roller-like member as in the prior art, and is attached to the punch attachment beam 8 via a punch attachment base 91.
[0021]
On the other hand, the four-point bending punches 10a and 10b have the same structure as each other, and have a structure in which the fulcrums 5a and 5b and the fulcrum steel plates 6a and 6b are turned upside down. That is, the left punch 10a will be described as a representative. The punch mounting beam 8 has an R surface having a shape in which the fulcrum 5a is turned upside down, that is, the lower end portion has a downward ridge line in a direction perpendicular to the span direction, or A punch fulcrum 100a formed in a wedge shape is attached via a punch mounting base 11a. A punch fulcrum steel plate 101a is supported on the punch fulcrum 100a so that the upper surface thereof is in line contact with the downward ridge line and is rotatable about an axis along the ridge line. The punch fulcrum steel plate 101a is divided into a punch upper member 102a whose upper surface is in line contact with the lower end ridge line of the punch fulcrum 100a, and a punch lower member 103a in which a pressing surface P is formed in contact with the test piece W on the lower surface. The punch lower member 103a is supported so as to be movable in the span direction with respect to the punch upper member 102a.
[0022]
The relationship between the punch upper member 102a and the punch lower member 103a is exactly the same as the relationship between the fulcrum 5a and the fulcrum steel plate 6a. The punch lower member 103a has a plurality of stroke bearings 104a that allow only linear movement in the span direction. In addition, the punch upper member 102a is supported by the guide bar 105a.
[0023]
Further, the relationship between the punch upper member 102a and the punch fulcrum 100a is equivalent to the relationship between the lower member 61a of the fulcrum steel plate 6a and the fulcrum 5a, and the position of the punch upper member 102a in the ridge line direction of the punch fulcrum 100a is The fulcrum 100a is controlled by the guide plates 106a arranged on both sides in the ridge line direction, and is punched in an unloaded state by two tension coil springs 107a interposed between the guide plates 106a on both sides and the punch upper member 102a. The rotational position of the upper member 102a is elastically restricted so that the upper surface of the upper member 102a is always along the substantially horizontal direction. The above configuration is exactly the same for the right punch fulcrum 100b and the punch fulcrum steel plate 101b.
[0024]
In the embodiment of the present invention described above, the punch 9 is attached in the case of the three-point bending test, and the punch 9 is removed in the case of the four-point bending, and the test piece W is supported on the supporting steel plates 6a and 6b. The crosshead 7 is lowered while being placed on S. In any test, when the test piece W bends as the test progresses, the entire fulcrum steel plates 6a and 6b rotate (tilt) according to the amount of the bend, and the support surface S and the lower surface of the test piece W And the upper members 62a and 62b of the fulcrum steel plates 6a and 6b move so as to approach each other following the approach of the two support positions of the test piece W accompanying the bending. Therefore, no slip occurs between the test piece W and the fulcrum steel plates 6a and 6b.
[0025]
In the case of a four-point bending test, when the test piece W bends due to the lowering of the two punches 10a and 10b, the entire punch fulcrum steel plates 101a and 101b are rotated according to the amount of the bend. The close contact state with the upper surface of W is maintained, and the punch lower members 103a and 103b of the punch fulcrum steel plates 101a approach each other following the approach of the two pressing positions of the test piece W accompanying the bending. Moving. Accordingly, no slip occurs between the test piece W and the punch fulcrum steel plates 101a and 101b.
[0026]
In the above embodiment, the punch upper members 102a and 102b and the punch lower member 103a between the lower members 61a and 61b of the fulcrum steel plates 6a and 6b and the upper members 62a and 62a and the punch fulcrum steel plates 101a and 101b. , 103b, a plurality of stroke bearings 63a or 104a and a plurality of guide bars 64a or 105a are interposed, but only the stroke bearings may be used. However, it is desirable to use both a stroke bearing and a guide bar as in the above example in order to withstand a test with a large load under a compact configuration.
[0027]
【The invention's effect】
As described above, according to the present invention, the fulcrum steel plate that comes into surface contact with the test piece disposed between the two fulcrums and the test piece in the bending test apparatus is provided with a support surface that comes into close contact with the test piece. It is divided into a member and a lower member that is supported so as to be rotatable with respect to the fulcrum, and the upper member is supported so as to be movable in the span direction with respect to the lower member. Even in a three-point or four-point bending test of a large specimen, there is no slippage between the fulcrum steel plate and the specimen as in the conventional case, and the effect on the friction is not included in the test results. It became possible to conduct the test.
[0028]
As for the two punches used in the four-point bending test, as in the invention according to claim 2, the punch lower member on which the pressing surface for pressing the test piece is formed and the punch supporting point are supported rotatably. If the punch lower member is supported so as to be movable in the span direction with respect to the punch upper member, a four-point bending test with a long span or a four-point bending test with a large bending deflection is performed. In this case, no slip occurs between the punch and the test piece, and the influence of the friction is not included in the test result, and an accurate four-point bending test can always be performed.
[Brief description of the drawings]
FIG. 1 is a front view showing an overall configuration of an embodiment of the present invention.
2A is a left side view of FIG. 1, and FIG. 2A is a left side view of the whole shown with the punch 9 omitted, and FIG. 2B is a left side view of the punch 9;
FIG. 3 is an enlarged front view of the vicinity of a right fulcrum steel plate 6a according to the embodiment of the present invention.
4 is a right side view of FIG. 3. FIG.
FIG. 5 is an enlarged front view of a main part in the vicinity of a punch mounting beam 8 according to an embodiment of the present invention.
6 is a left side view of the punch 10a in FIG.
FIG. 7 is a diagram showing a configuration example of a main part of a bending test apparatus using a conventional fulcrum steel plate.
[Explanation of symbols]
1 portal frame 3 fulcrum mounting beams 4a and 4b fulcrum mounting bases 5a and 5b fulcrum 6a and 6b fulcrum steel plates 61a and 61b lower members 62a and 62b upper members 63a stroke bearings 64a guide bars 65a guide plates 66a tension coil springs 7 crossheads 8 Punch mounting beam 9 punch (for 3-point bending)
10a, 10b punch (for 4-point bending)
100a, 100b Punch fulcrum 101a, 101b Punch fulcrum steel plate 102a Punch upper member 103a Punch lower member 104a Stroke bearing 105a Guide bar 106a Guide plate 107a Tensile coil spring S Support surface P Press surface

Claims (2)

Two fulcrum points are arranged at a predetermined distance from each other in the horizontal direction, and a fulcrum steel plate having a test piece support surface on the upper surface is perpendicular to the separation direction of the two fulcrum points. 1 or 2 punches are provided so as to be movable in the vertical direction, and the test piece is supported from the lower surface by the test piece support surface of each fulcrum steel plate. In a bending test apparatus for performing a three-point or four-point bending test on a test piece by pressing the one or two punches against the upper surface of the test piece in a supported state,
Each of the fulcrum steel plates includes a lower member that is rotatably supported with respect to the fulcrum, and an upper member on which a test piece support surface that contacts the lower surface of the test piece is formed. On the other hand, the bending test apparatus is supported so as to be movable in the separation direction of the two fulcrums. Each of the two punches for performing the four-point bending test on the test piece is supported so as to be rotatable around a horizontal axis perpendicular to the separation direction of the two fulcrums with respect to the vertical movement mechanism. An upper member and a punch lower member formed with a test piece pressing surface abutting against the upper surface of the test piece, and supported so as to be movable in a direction away from the two fulcrums with respect to the punch upper member; The bending test apparatus according to claim 1, wherein:

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