Four-point bending testing device

Abstract

The utility model relates to a four-point bending testing device which comprises a testing platform, machine feet are fixedly connected to the two sides of the testing platform, a machine frame is fixedly connected to the testing platform, a movable cross beam is inserted into the machine frame, an upper clamp is fixedly connected to the middle of the movable cross beam, a lower clamp is fixedly connected to the portion, under the upper clamp, of the testing platform, and each of the lower clamp and the upper clamp comprises a connecting base. The connecting seat is fixedly connected with a grooved rail, and the grooved rail is slidably connected with two groups of test fulcrums. A horizontal and transverse graduated scale placement groove is formed in the front end face of the grooved rail, a plurality of rectangular clamping grooves are formed in the bottom face of the upper portion of the graduated scale placement groove, vertical L-shaped clamping rear plates are inserted into the clamping grooves, and the front ends of the clamping rear plates extend out of the grooved rail to form vertical clamping front plates. A clamping groove is formed between the lower portion of the front clamping plate and the rear clamping plate. According to the four-point bending testing device, the connecting structure of the graduated scale is designed and improved, the structure is simple and compact, and the graduated scale is convenient to mount and dismount.

Description

Technical fields:

[0001] This utility model relates to the technical field of bending testing, and more specifically to a four-point bending testing device. Background technology:

[0002] Currently, the fuselage and wings (including sides and tail) of the DA40 NG aircraft are generally made of composite materials, mainly using multiple layers of fiber cloth, resin, and adhesives for curing. Before the DA40 NG aircraft is completed, it needs to meet certain performance requirements to ensure safe flight. For example, the shells that make up the fuselage and wings need to meet certain requirements. Currently, the performance testing method for fiber materials is the three-point bending test. The three-point bending test supports the two ends of the sample and applies a single concentrated load in the middle to form a transverse bending (with shear force and bending moment). Because the maximum stress is concentrated near the loading point, local defects may be masked. It is simple to operate and only suitable for thin samples or rapid industrial production testing. The data from the three-point bending test cannot guarantee the safe flight of the DA40 NG aircraft, so a more accurate performance testing method is needed. Therefore, some people have proposed the four-point bending test, which requires the use of corresponding four-point bending testing equipment.

[0003] Existing four-point bending test equipment generally has an upper clamp that can move up and down and a fixed lower clamp. The upper clamp has two sets of test support points, and the lower clamp also has two sets of test support points. The distance between the test support points needs to be adjusted, and a scale is used as a reference during the adjustment process. Because the four-point bending test of aircraft parts is a test with high precision requirements, the test support points and scale need to be disassembled and inspected before each test. They are then reinstalled after meeting the requirements. The scale is generally fixed to the equipment by clips and bolts, which is relatively troublesome to install and disassemble. Therefore, a structure that facilitates its disassembly needs to be designed. Utility Model Content:

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a four-point bending test device, which features a scale that is easy to install and remove.

[0005] A four-point bending test device includes a test platform with feet fixedly connected to both sides. A U-shaped frame is fixedly mounted on the test platform, and a movable crossbeam is inserted inside the frame. A lead screw drive mechanism is connected to the movable crossbeam and is located inside the frame, driving the movable crossbeam to move up and down. An upper clamp is fixedly mounted to the middle of the movable crossbeam, and a lower clamp is fixedly mounted on the test platform directly below the upper clamp. Both the lower and upper clamps include a connecting seat, and a horizontal [unclear - possibly a component or element] is fixedly mounted on the connecting seat. A transverse groove rail has two sets of test support points slidably connected on it; a force sensor is set between the connecting seat of the upper clamp and the moving crossbeam; a horizontal scale mounting groove is formed on the front end face of the groove rail; several rectangular clamping grooves are formed on the bottom surface above the scale mounting groove; a vertical L-shaped clamping back plate is inserted into the clamping groove; a vertical clamping front plate is formed on the front end of the clamping back plate extending out of the groove rail; a slot is formed between the lower part of the clamping front plate and the clamping back plate.

[0006] A scale is inserted into the scale mounting groove of the groove rail. The rear end face of the scale abuts against the bottom surface of the scale mounting groove. The upper part of the scale is inserted into the slot between the clamping front plate and the clamping rear plate and presses against the clamping front plate. A screw is screwed to the upper part of the clamping front plate and the screw is screwed to fix it on the groove rail.

[0007] Preferably, the upper part of the groove rail is formed with several countersunk holes opposite to the screws, and a spring is inserted into the countersunk hole. One end of the spring presses against the bottom surface of the countersunk hole, and the other end presses against the clamping front plate.

[0008] Preferably, the width of the groove between the clamping front plate and the clamping rear plate is greater than the thickness of the scale, and the thickness of the scale is greater than the depth of the scale mounting groove.

[0009] Preferably, a central reference block is provided between the test fulcrums, and the central reference block is inserted and fixed in the middle of the groove rail.

[0010] Preferably, the test fulcrum includes an "I"-shaped slider, which is inserted into the groove of the rail. One side of the slider abuts against an L-shaped support member, and a fastening bolt is inserted into the support member. The fastening bolt is screwed and fixed to the slider. A vertical positioning bolt is screwed onto the slider, and the end of the positioning bolt presses against the rail.

[0011] The support member is formed with several vertically distributed longitudinal insertion holes.

[0012] Preferably, a fulcrum auxiliary adjustment component is provided between the test fulcrums;

[0013] The fulcrum auxiliary adjustment component includes a horizontal adjustment base. On both sides of the adjustment base, there are respectively sleeved with "C"-shaped hinge brackets. The hinge brackets are hinged on the adjustment base through hinge shafts. Diagonal support rods are respectively formed at the front and rear ends of the hinge brackets. The upper ends of the diagonal support rods are located at the front and rear sides of the support member and are inserted with T-shaped pins. The pins are inserted into the support member of the support member; a adjustment knob is pivotally connected to the middle of the adjustment base. A vertical stud is screwed inside the adjustment knob, and the upper end of the stud is screwed and fixed to the middle of the central reference block.

[0014] Preferably, a threaded hole opposite to the stud is formed in the middle of the central reference block. The stud is screwed into the threaded hole of the central reference block and is screwed with a juxtaposed nut, and the juxtaposed nut presses against the central reference block.

[0015] Preferably, a connecting sleeve is formed at the upper end of the adjustment knob. The upper end of the connecting sleeve passes through the adjustment base and is inserted and fixedly connected with a limit sleeve. The limit sleeve and the adjustment knob respectively abut against the upper and lower end faces of the adjustment base.

[0016] The beneficial effects of the present utility model are as follows:

[0017] 1. The four-point bending test device of the present utility model designs and improves the connection structure of the scale ruler, and its structure is simple and compact, which is convenient for the installation and disassembly of the scale ruler.

[0018] 2. The four-point bending test device of the present utility model also proposes an auxiliary adjustment structure for the test fulcrum, which can facilitate the adjustment of the test fulcrum position and improve the positioning accuracy of the test fulcrum position at the same time. Description of the drawings:

[0019] Figure 1 It is a schematic structural diagram of the front view of the present utility model;

[0020] Figure 2 It is a three-dimensional structural diagram of the test fulcrum part of the present utility model;

[0021] Figure 3 It is a schematic structural diagram of the front view of the test fulcrum part of the present utility model;

[0022] Figure 4 is Figure 3 The sectional structural schematic diagram at A-A in

[0023] In the figure: 1. Test platform; 2. Machine feet; 3. Frame; 4.Moving crossbeam; 5. Connecting seat; 6. Groove rail; 7. Force measuring sensor; 8. Test fulcrum; 9. Fulcrum auxiliary adjustment component; 10. Central reference block; 11. Scale ruler; 12. Clamping rear plate; 13. Screw; 14. Spring. Specific implementation manners:

[0024] Example: See Figures 1 to 4As shown, a four-point bending test device includes a test platform 1, with legs 2 fixedly connected to both sides of the test platform 1. A U-shaped frame 3 is fixedly attached to the test platform 1, and a movable crossbeam 4 is inserted inside the frame 3. A screw drive mechanism is connected to the movable crossbeam 4, and the screw drive mechanism is located inside the frame 3 and drives the movable crossbeam 4 to move up and down. An upper clamp is fixedly attached to the middle of the movable crossbeam 4, and a lower clamp is fixedly attached to the test platform 1 directly below the upper clamp. Both the lower clamp and the upper clamp include a connecting seat 5, and a horizontal transverse groove rail is fixedly attached to the connecting seat 5. 6. Two sets of test support points 8 are slidably connected on the groove rail 6 respectively; a force sensor 7 is set between the connecting seat 5 of the upper clamp and the moving crossbeam 4; a horizontal scale mounting groove 61 is formed on the front end face of the groove rail 6; a number of rectangular clamping grooves 62 are formed on the bottom surface of the upper part of the scale mounting groove 61; a vertical L-shaped clamping rear plate 12 is inserted into the clamping groove 62; a vertical clamping front plate 121 is formed on the front end of the clamping rear plate 12 extending out of the groove rail 6; a slot is formed between the lower part of the clamping front plate 121 and the clamping rear plate 12.

[0025] A scale 11 is inserted into the scale mounting groove 61 of the groove rail 6. The rear end face of the scale 11 abuts against the bottom surface of the scale mounting groove 61. The upper part of the scale 11 is inserted into the slot between the clamping front plate 121 and the clamping rear plate 12 and presses against the clamping front plate 121. A screw 13 is screwed onto the upper part of the clamping front plate 121 and is screwed and fixed to the groove rail 6.

[0026] The upper part of the groove 6 is formed with several countersunk holes 63 opposite to the screws 13. A spring 14 is inserted into the countersunk hole 63. One end of the spring 14 presses against the bottom surface of the countersunk hole 63 and the other end presses against the clamping front plate 121. When the screws 13 are loosened, the spring 14 will push the clamping front plate 121 outward, which is equivalent to pushing the scale 11 out of the scale mounting slot 61, making it convenient to remove the scale 11.

[0027] The width of the slot between the front clamping plate 121 and the rear clamping plate 12 is greater than the thickness of the scale 11, and the thickness of the scale 11 is greater than the depth of the scale mounting slot 61.

[0028] A central reference block 10 is provided between the test fulcrums 8. The central reference block 10 is inserted and fixed in the middle of the groove rail 6. The central reference block 10 is used for calibration of the test fulcrums 8 before testing.

[0029] The described test fulcrum 8 includes an "I"-shaped slider 81. The slider 81 is inserted into the groove of the groove rail 6. One side of the slider 81 abuts against an L-shaped support member 82. A fastening bolt 83 is inserted into the support member 82, and the fastening bolt 83 is screwed and fixed on the slider 81. A vertical positioning bolt 84 is screwed on the slider 81, and the end of the positioning bolt 84 presses against the groove rail 6; an arc-shaped groove is formed on the slider 81, and an arc-shaped rib is formed on the slider 81. The arc-shaped rib is inserted into the arc-shaped groove of the slider 81, and the slider 81 is mainly fixed on the groove rail 6 by locking the positioning bolt 84.

[0030] A number of vertically distributed longitudinal jacks 821 are formed on the support member 82, and the longitudinal jacks 821 can damage the strength of the support member 82. When the strength of the test piece is higher than the upper limit of the applied pressure during the test, the four-point bending test device can first damage the support member 82 to achieve self-protection.

[0031] A fulcrum auxiliary adjustment component 9 is provided between the test fulcrums 8; because the above-mentioned test fulcrum 8 is mainly positioned by tightening the positioning bolt 84, but the force when tightening the positioning bolt 84 will also cause the test fulcrum 8 to deviate slightly, so the fulcrum auxiliary adjustment component 9 is designed to fix the test fulcrum 8 first, preventing the test fulcrum 8 from deviating slightly and affecting the test accuracy;

[0032] The fulcrum auxiliary adjustment component 9 includes a horizontal adjustment seat 91. On both sides of the adjustment seat 91, "C"-shaped hinge brackets 92 are respectively sleeved. The hinge brackets 92 are hinged on the adjustment seat 91 through hinge shafts. Diagonal struts 921 are respectively formed at the front and rear ends of the hinge brackets 92. The upper ends of the diagonal struts 921 are located at the front and rear sides of the support member 82 and a T-shaped pin 95 is inserted. The pin 95 is inserted into the support member 82 of the support member 82; a adjustment knob 93 is pivotally connected in the middle of the adjustment seat 91. A vertical stud 94 is screwed in the adjustment knob 93, and the upper end of the stud 94 is screwed and fixed in the middle of the central reference block 10; at the same time, the above-mentioned fulcrum auxiliary adjustment component 9 realizes the up and down movement of the adjustment seat 91 by rotating the adjustment knob 93, and then drives the movement of the support member 82 by the opening and closing of the diagonal struts 921, facilitating the adjustment of the position of the support member 82.

[0033] A screw hole opposite to the stud 94 is formed in the middle of the central reference block 10. The stud 94 is screwed into the screw hole of the central reference block 10 and a juxtaposed nut 96 is screwed. The juxtaposed nut 96 presses against the central reference block 10, and the juxtaposed nut 96 can limit the rotation of the stud 94.

[0034] The upper end of the adjustment knob 93 is formed with a connecting sleeve 931. The upper end of the connecting sleeve 931 passes through the insertion sleeve of the adjustment seat 91 and is fixedly connected to the limiting sleeve 97. The limiting sleeve 97 and the adjustment knob 93 abut against the upper and lower end surfaces of the adjustment seat 91, respectively, which is the pivot structure of the adjustment knob 93.

[0035] Working principle: This structure is a four-point bending test device. Its technology is mainly reflected in the connection structure of the scale 11. The scale 11 is set in the scale mounting groove 61 of the groove rail 6 and is fixedly connected to the groove rail 6 by the buckle formed by the clamping plate 12. When disassembling, the clamping plate 12 can be pulled out of the groove rail 6 by loosening the screw 13 and then removed. Disassembly is convenient. Installation can be achieved in the opposite way. Installation and disassembly are also convenient.

[0036] Meanwhile, the scale 11 has no holes, so its position can be adjusted by moving the scale 11 without tightening the screw 13.

[0037] The embodiments described above are illustrative of the present invention and are not intended to limit the present invention. Any person skilled in the art can modify the embodiments without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be as set forth in the claims.

Claims

1. A four-point bending test device, comprising a test platform (1), with machine feet (2) fixedly connected to both sides of the test platform (1). A "冂"-shaped frame (3) is fixedly connected to the test platform (1). A moving crossbeam (4) is inserted into the frame (3). A lead screw driving mechanism is connected to the moving crossbeam (4), and the lead screw driving mechanism is arranged inside the frame (3) and drives the moving crossbeam (4) to move up and down. A upper fixture is fixedly connected to the middle of the moving crossbeam (4), and a lower fixture is fixedly connected to the test platform (1) directly below the upper fixture. Both the lower fixture and the upper fixture include a connecting seat (5). A horizontally transverse groove rail (6) is fixedly connected to the connecting seat (5). Two groups of test supports (8) are respectively slidably connected to the groove rail (6). A force measuring sensor (7) is arranged between the connecting seat (5) of the upper fixture and the moving crossbeam (4). It is characterized in that: On the front end face of the groove rail (6), a horizontally transverse scale ruler placement groove (61) is formed. On the bottom surface of the upper part of the scale ruler placement groove (61), a number of rectangular clamping grooves (62) are formed. A vertically L-shaped clamping rear plate (12) is inserted into the clamping groove (62). The front end of the clamping rear plate (12) extends out of the groove rail (6) to form a vertical clamping front plate (121). A clamping groove is formed between the lower part of the clamping front plate (121) and the clamping rear plate (12). A scale ruler (11) is inserted into the scale ruler placement groove (61) of the groove rail (6). The rear end face of the scale ruler (11) abuts against the bottom surface of the scale ruler placement groove (61). The upper part of the scale ruler (11) is inserted into the clamping groove between the clamping front plate (121) and the clamping rear plate (12) and presses against the clamping front plate (121). A screw (13) is screwed on the upper part of the clamping front plate (121), and the screw (13) is screwed and fixed on the groove rail (6).

2. The four-point bending test device according to claim 1, characterized in that: A number of counterbores (63) opposite to the screws (13) are formed on the upper part of the groove rail (6). A spring (14) is inserted into the counterbore (63). One end of the spring (14) presses against the bottom surface of the counterbore (63), and the other end presses against the clamping front plate (121).

3. The four-point bending test device according to claim 1, characterized in that: The groove width of the clamping groove between the clamping front plate (121) and the clamping rear plate (12) is greater than the thickness of the scale ruler (11), and the thickness of the scale ruler (11) is greater than the depth of the scale ruler placement groove (61).

4. The four-point bending test device according to claim 1, characterized in that: A central reference block (10) is provided between the test fulcrums (8), and the central reference block (10) is inserted and fixed in the middle of the groove rail (6).

5. A four-point bending test device according to claim 4, characterized in that: The test fulcrum (8) includes an "I"-shaped slider (81). The slider (81) is inserted into the groove of the groove rail (6). One side of the slider (81) abuts against an L-shaped support member (82). A fastening bolt (83) is inserted into the support member (82), and the fastening bolt (83) is screwed and fixed on the slider (81). A vertical positioning bolt (84) is screwed on the slider (81), and the end of the positioning bolt (84) presses against the groove rail (6). A number of vertically distributed longitudinal insertion holes (821) are formed on the support member (82).

6. A four-point bending test device according to claim 5, characterized in that: A fulcrum auxiliary adjustment component (9) is provided between the test fulcrums (8). The fulcrum auxiliary adjustment component (9) includes a horizontal adjustment seat (91). On both sides of the adjustment seat (91), a "C"-shaped hinge bracket (92) is sleeved respectively. The hinge bracket (92) is hinged on the adjustment seat (91) through a hinge shaft. Diagonal support rods (921) are formed at the front and rear ends of the hinge bracket (92) respectively. The upper ends of the diagonal support rods (921) are located at the front and rear sides of the support member (82) and are inserted with a T-shaped pin (95). The pin (95) is inserted into the support member (82) of the support member (82). A adjusting knob (93) is pivotally connected in the middle of the adjustment seat (91). A vertical stud (94) is screwed in the adjusting knob (93), and the upper end of the stud (94) is screwed and fixed in the middle of the central reference block (10).

7. A four-point bending test device according to claim 6, characterized in that: The center reference block (10) has a threaded hole formed in the middle that is opposite to the stud (94). The stud (94) is screwed into the threaded hole of the center reference block (10) and is screwed with a nut (96). The nut (96) presses against the center reference block (10).

8. A four-point bending test device according to claim 6, characterized in that: The upper end of the adjustment knob (93) is formed with a connecting sleeve (931). The upper end of the connecting sleeve (931) passes through the insertion sleeve of the adjustment seat (91) and is fixed to a limiting sleeve (97). The limiting sleeve (97) and the adjustment knob (93) abut against the upper and lower end surfaces of the adjustment seat (91), respectively.

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