JPH0257858B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION There are many types of beam structures as shown in FIGS. 20a to 20o. That is, these have a fixed fulcrum A, a stationary movable fulcrum B, a horizontally movable fulcrum B', and an elastic fulcrum C. For example, a in FIG.
A simple beam with both ends of the beam supported by a stationary movable fulcrum RO and a horizontal movable fulcrum RO', with one end supported by a stationary movable fulcrum RO and the middle of the beam supported by a horizontal movable fulcrum RO'.
c is a beam with one end supported by a fixed movable fulcrum B and the middle of the beam is supported by a horizontally movable fulcrum B', respectively. Two-span continuous beam supported by fulcrums A' and B', e is a cantilever beam with only one end of the beam as a fixed fulcrum A, f is a beam with one end fixed and the other end movable, g is an overhanging beam with one end fixed and the other end movable, h is a two-span continuous beam with one end fixed and the other end movable; i is a Gelbar beam with a bending point D formed in the middle; j is an elastic beam in which the movable fulcrum B' in a above is changed to an elastic fulcrum C; Examples of elastic beams using an elastic fulcrum C are shown below.

In the present invention, such multi-type beam structures are formed as models for each type, and the mechanical phenomena of each beam structure can be visually observed directly, and the amount of deflection, deflection angle, degree of bending stress, fulcrum reaction force, The purpose is to obtain a general-purpose experimental device that can be used to easily conduct experiments on influence lines, Young's modulus, bending moment diagrams, shear force diagrams, etc., and can be used for training on beam structures in civil engineering, architecture, and machinery. An experimental support stand that can be placed horizontally on the floor, three types of fulcrum members that can be moved along the horizontal support stand and fixed at desired positions: fixed support, movable support, and elastic support; A test beam of a predetermined size that is installed on a support base using a selected fulcrum member and supported by it to form a span, a weight for concentrated load on the test beam, and a partially equally distributed load. A block-shaped weight for use as well as a roller chain of a predetermined length for uniformly distributed loading are used, and a test beam with a span is moved along the length and stopped at a predetermined position to provide a measuring stylus. It consists of a trial beam and an appropriate number of dial gauges that are brought into contact with the fulcrum member.

Embodiments of the present invention will be described with reference to the drawings.

In the drawing, reference numeral 1 denotes a support stand for the experimental equipment installed on the floor, and a height adjustment mechanism 2 is provided at the bottom of the leg, and by adjusting the height adjustment mechanism 2, the top surface of the support stand 1 is always maintained horizontally at a predetermined height. The upper surface of the support base 1 is provided with parallel tracks 3 and 4 for moving a fulcrum member, which will be described later, with a space between the front and back, and a track 5 for moving a dial gauge, which will be described later, parallel to this. were provided, and each track was provided with a length scale 6.

Various types of test beams 7 are prepared so that the length, width, and thickness can be applied to the experimental content, and materials of metal, wood, synthetic resin, and other materials are prepared. As shown in the figure, a mounting hole 7a for tying is provided in the fulcrum member at an appropriate location, and as a special beam, a gel bar beam type specimen having a bending part 7b formed by a hinge in the middle as shown in FIG. 18 is also prepared. .

Three types of fulcrum members are used to form a span on which the test beam 7 is mounted: one that supports the beam 7 fixedly, one that supports it movably, and one that supports it elastically.

The fixed fulcrum member 8 clamps and fixes the beam 7 between the receiving member 8a and the pressing member 8b as shown in FIGS. 4 and 5, and the movable fulcrum member is shown in FIGS. 6 and 7.
As shown in FIG. 8 and FIG. 8, a shaft piece 9b is rotatably mounted on a bearing member 9a, a beam 7 is fastened to the shaft piece 9b with a set screw 9c, and the shaft piece 9b is fixed at a fixed position. There is a shaft piece 9 which can be rotated, a shaft piece 9b made by connecting the beam 7 with a screw, and a shaft piece 9' which can be rotated and horizontally moved within the elongated hole 9d of the bearing member 9a. 10, as shown in FIGS. 9 and 10, an elastic spring 10a is applied below the movable fulcrum members 9, 9'.

And these three types of branch members 8, 9, 10
As shown in FIGS. 4 to 10, the pressing member 8
b and the bearing member 9a are used by being removably connected to the fulcrum mounting piece 11 with a locking screw 12, and the fulcrum mounting piece 11 is connected to the shaft member 1 which is connected to the lower surface of the bearing member 9a.
The fixed fulcrum member 8 and the movable fulcrum members 9, 9' are provided with two screws between the fulcrum mounting piece 11 and the base cylinder 15. The height of the fulcrum members 8, 9, 9' connected to the mounting piece 11 can be adjusted by adjusting the expansion and contraction of the telescopic cylinder 16 formed by screwing together the cylinders 16a and 16b. In 10, an elastic spring 10a is interposed in place of the telescopic tube 16 to allow elasticity in the vertical direction, and the holding plate 17 is stopped along the lower surface of the base plate 14 of each fulcrum member 8, 9, 10. Tracks 3 and 4 are attached with screws 18 and formed on the upper part of the support base 1 by the substrate 14 and the holding plate 17.
The fulcrum position relative to the beam 7 can be set arbitrarily by holding the base plate 14 and the holding plate 17 together and fixing them to the track by moving the base plate 14 in the length direction of the track and tightening the set screw 18 at an arbitrary position. I did it like that.

Incidentally, by suspending a weight from a hook piece 19 provided at the lower end of the shaft member 13 of each fulcrum member 8, 9, 10, the fulcrum member is prevented from flying upward during the experimental operation.

The following three types of load application means were used for the beam 7 which was supported on the fulcrum members 8, 9, and 10 to form a span. That is, for concentrated loads, a plurality of weights 20 of a predetermined weight as shown in FIG. 11 are used; for partially uniformly distributed loads, a plurality of block type weights 21 of a predetermined weight are used as shown in FIG. 12; For uniformly distributed loads, one or more roller chains 22 of a predetermined length are connected in a planar manner as shown in FIG. 14.

The weight 20 is used by attaching a hanging ring 23 shown in FIG. 16 to a beam 7 formed with a span as shown in FIG. 2, and supporting it on a weight receiver 24 suspended from this. In addition, as shown in FIG. 13, the block type weights 21 are placed adjacent to each other over a predetermined length on a beam 7, and in this case, due to the deflection of the beam 7, frictional restraint is created between adjacent blocks. It is desirable that one or both sides of the weight 21 have a tapered surface to prevent this from occurring. Furthermore, the roller chain 22 has a length that corresponds to the effective span length of the beam 7, as shown in FIG. 15, and is mounted along the length direction of the beam 7. As shown in FIG. 15, it is preferable to interpose a membrane material 25 between the polymerized parts to ensure that the rollers of the polymerized chain 22 are vertically polymerized so that the load is distributed evenly in the length direction. If this roller chain can be disassembled into appropriate lengths by known means, it can be used for equally distributed loads in the same manner as the block type weight 21. A dial gauge 26 for measuring various mechanical values is mounted on the support base 1.
It is attached to a transverse rod 30 of a post 29 erected on a sliding member 28 which can move freely along the upper track 5 in the length direction of the beam 7 and can be fixed in position with a locking screw 27.
A plurality of dial gauges 26 are provided in the length direction of the beam 7, and the measuring point 31 thereof is brought into contact with the top surface of the beam 7 as shown in FIG. 6, or fixed to each fulcrum member 8, 9, 10 as shown in FIG. 4. For example, the amount of deflection of the beam 7 or the reaction force of the fulcrum is measured by making contact with the surface of the receiving piece 32, and the height and longitudinal position of the beam 7 can be adjusted freely. As shown in FIGS. 1 to 3, the present invention comprises a fixed fulcrum member 8, a movable fulcrum member 9, 9', and an elastic fulcrum member on the tracks 3, 4, 5 on the support base 1. 10, select the appropriate one according to the content of the experiment,
Move and fix this to a desired location, select an appropriate specimen beam 7, and support it on the positioned fulcrum member. They are clamped and fixed, and the beams 7 are connected to the respective shaft pieces 9b with screws 9c in the movable fulcrum members 9, 9' and the elastic fulcrum members 10 to form a span, and then the weights 20, An appropriate number of block-type weights 21 are placed as a partially uniformly distributed load, and an appropriate number of roller chains 22 of a predetermined length are placed as a uniformly distributed load to create a state in which a load is applied to the beam 7. By directly visually observing the mechanical phenomena that change depending on the load, we learned the theory of the beam structure, and by moving the dial gauge 26 along the track 5 in the length direction of the beam 7 to be inspected. Measure the amount of deflection or fulcrum stress at a desired location, and then attach a strain gauge to measure bending stress, etc., or use an optical lever to measure the deflection angle, influence line, Young's modulus, and more. By detecting numerical values at each position in the longitudinal direction of the beam 7 using the dial gauge 26, it is possible to know the form of the bending moment diagram or shear force diagram in the longitudinal direction of the beam 7, as illustrated in FIG. Mechanical experiments of all kinds of beam structures can be easily performed with one device.

Note that A in Fig. 19 is for the simple beam structure a in Fig. 20, and the concentrated load weight 20
B is when the block type weight 21 for partially uniformly distributed load is applied to the two-span continuous beam structure of d, and C is the case when the cantilever beam of e is the target. Roller chain 2 as distributed load
2 and to measure its deflection angle, a mirror 32 is placed on the free end of the beam 7, and its vertical movement is measured using a lever, with a scale 33 interposed, and D is the same. i's gelbar beam,
E shows the experimental mode of the elastic beam shown in c.

In this way, according to the present invention, several types of specimen beams with different lengths and widths, three types of fulcrum members (fixed, movable, and elastic), weights for concentrated loads, and block-type weights for partially uniformly distributed loads are used. Using a roller chain to distribute the load equally, the selected fulcrum member is placed at the set position on the experimental support stand, and the selected specimen beam is supported on it to form a span, and the appropriate load of the three types mentioned above is applied. It is possible to create a mechanical experimental device for any type of beam structure on a support stand by using or using a combination of objects to load the beam, so it is easy to understand the mechanical theory of various beams and the fluctuations of beams due to loads. As a result, it is extremely useful for research and learning of beam structures in civil engineering, architecture, and machinery.Moreover, its structure is relatively simple and inexpensive, and its handling and operation are easy and convenient.

[Brief explanation of drawings]

The drawings show an embodiment of the device of the present invention, and FIG. 1 is a plan view of the entire device, FIG. 2 is a front view, and FIG.
4 is a cutaway side view of the fixed fulcrum member, FIG. 5 is a cutaway front view, FIG. 6 is a cutaway side view of the movable fulcrum member, and FIG. 7 is a front view of the stationary movable fulcrum member. Figure 8 is a front view of the horizontal movable fulcrum member, Figure 9 is a side view of the elastic fulcrum member, Figure 10 is its front view, Figure 11 is a perspective view of the weight, and Figure 12 is a perspective view of the block type weight. , FIG. 13 is a front view of the block type weight in use, FIG. 14 is a plan view of the roller chain, FIG. 15 is a front view of the block type weight in use, and
Fig. 6 is a perspective view of a ring for hanging weights, Fig. 17 is a perspective view showing an example of a specimen beam, Fig. 18 is a perspective view of a Gelber beam, and Fig. 19 shows an embodiment of the experimental apparatus according to the present invention. Front view, FIG. 20 is a front diagram illustrating the types of beam structures. 1... Experimental support stand, 3, 4, 5... Orbit, 7
...Specimen beam, 8...Fixed fulcrum member, 9,9'
...Movable fulcrum member, 10...Elastic fulcrum member, 20
... Weight, 21 ... Block type weight, 22 ... Roller chain, 26 ... Dial gauge, 31 ...
...Measuring head.

Claims (1)

[Claims] 1. An experimental support stand that can be placed horizontally on the floor; three types of fulcrum members for fixed support, movable support, and elastic support that can be moved along the horizontal support and fixed at desired positions; A test beam of a predetermined size is installed on a support base by selectively using these fulcrum members and supported by it to form a span, and distribution of weights, parts, etc. for concentrated loads on the test beam. A block-type weight for loading, a roller chain of a predetermined length for uniformly distributed loading, and a test beam with a span are moved along the length and stopped at a predetermined position to set the measuring head. A mechanical experimental device with a beam structure consisting of a test beam and an appropriate number of dial gauges that are brought into contact with a fulcrum member.