Device for preventing secondary impact in drop hammer impact test

Abstract

The invention relates to the technical field of building structure test devices, and discloses a drop hammer impact test secondary impact prevention device which comprises an impact part annularly installed on the outer ring of a drop hammer and a backing ring arranged above a test piece, the impact part comprises a fixing ring annularly sleeved and fixed outside the drop hammer, and a plurality of paired side plates are annularly distributed on the outer ring of the fixing ring; the diameter of a circle where the outer side edges of the side plates are located is smaller than the diameter of the backing ring, a connecting plate is fixed between the two side plates in pairs, a pin shaft is arranged between the two side plates in pairs, a torsion spring is annularly sleeved on the pin shaft, one torsion foot of the torsion spring abuts against the outer side of the lower portion of the connecting plate, and the other torsion foot of the torsion spring abuts against the inner side of a pop-up type supporting foot rotationally installed on the pin shaft. The lower end of the pop-up supporting leg pops up from the position between the two side plates and is fixedly clamped on the backing ring; and a limiting sliding ring is annularly sleeved on the outer side edge of the side plate in the popping-out direction of the popping-out type supporting leg.

Description

Technical Field

[0001] The invention relates to the technical field of building structure test devices, in particular to a secondary impact protection device for a drop hammer impact test. Background Art

[0002] Accidents may cause partial or overall deformation of structural components, and in severe cases, the structure may collapse. In the current device system, the drop hammer test is a key link in evaluating the impact resistance of the specimen. The drop hammer impact tester can lift a certain mass of drop hammer to a predetermined height, hit the specimen through free fall, and then evaluate its impact resistance and other indicators.

[0003] However, the weight of the falling hammer in the drop hammer impact test is as high as about 500kg. After completing the initial impact on the specimen, the falling hammer will often bounce up due to the huge impact force. Due to its own huge weight, the subsequent movement trajectory is extremely difficult to control. After bouncing up, the falling hammer will quickly fall again, resulting in a secondary impact.

[0004] The emergence of this secondary impact has a direct negative impact on the analysis accuracy of the specimen's impact resistance. When conducting impact resistance analysis, the data interference caused by the secondary impact makes it extremely difficult to accurately evaluate the specimen's true impact resistance, which in turn seriously affects the reliability of the design method based on the test results. What is more serious is that the hammer may cause serious secondary and multiple damage to the specimen after it rebounds. Due to the huge weight of the hammer, subsequent impacts further exert force on the damaged parts of the specimen, aggravating the degree of damage and causing more complex and unpredictable failure modes in the internal structure of the specimen.

[0005] To address this problem, the existing technology usually adopts the method of pulling the falling weight to avoid secondary impact. However, in actual operation, it is found that this method is not feasible. Due to the huge weight of the falling weight, the strong pulling force generated at the moment of impact will cause a huge load on the device or structure used to pull the falling weight, which is very likely to cause damage to related equipment, making this control solution difficult to implement effectively.

[0006] In summary, the drop weight in the existing device will bounce up and fall again after hitting the specimen, causing a secondary impact, which directly affects the analysis accuracy of the specimen's impact resistance and the reliability of the design method. In addition, the drop weight's rebound and subsequent impact may cause more serious secondary and multiple damages. Therefore, it is necessary to invent a test device that can prevent secondary impacts in a drop weight impact test system. Summary of the invention

[0007] In order to solve a series of problems such as the drop hammer impact test device currently used for testing, the drop hammer hits the specimen and then bounces back and falls again to produce a secondary impact, which affects the accuracy of the specimen's impact resistance performance analysis and the reliability of the design method, and may cause serious secondary and multiple damages, the present invention provides a drop hammer impact test anti-secondary impact device.

[0008] The present invention is implemented by the following technical scheme: it includes an impact part mounted on the outer ring of the drop hammer and a support ring arranged above the test piece, the impact part includes a fixed ring which is fixed to the outside of the drop hammer by a ring sleeve, a plurality of paired side plates are arranged on the outer ring of the fixed ring, the diameter of the circle where the outer edge of the side plate is located is smaller than the diameter of the support ring, a connecting plate is fixed between the two paired side plates, a pin is provided between the two paired side plates, a torsion spring is sleeved on the pin, one torsion leg of the torsion spring presses against the outer side of the lower part of the connecting plate, the other torsion leg of the torsion spring presses against the inner side of a pop-up support leg rotatably mounted on the pin, and the lower end of the pop-up support leg pops out from between the two side plates and is fixed on the support ring; the outer edge of the side plate is located on the pop-up direction of the pop-up support leg and is sleeved with a limiting sliding ring.

[0009] During implementation, it includes an impact part mounted on the outer ring of the drop hammer and a support ring arranged above the specimen. The support ring can be fixed above the specimen restraint device and is always kept fixed. There is no restriction on this fixing method. The impact part includes a fixing ring fixed on the outside of the drop hammer by a ring sleeve. The fixing ring is fixed on the outer ring of the drop hammer. A plurality of paired side plates are arranged on the outer ring of the fixing ring. There are 6 pairs of side plates. The paired side plates are arranged axially along the fixing ring. The side plates are welded to the outer edge of the fixing ring, and the side plates are vertical. The diameter of the circle where the outer edge of the side plate is located is smaller than the diameter of the support ring, that is, the impact part can pass through the support ring. A connecting plate is fixed between the two paired side plates. A pin is provided between the two paired side plates, that is, a pin hole is opened at the same position of the two side plates, and the pin passes through the pin hole. The torsion spring and the pop-up support foot are installed through the pin. The pin shaft is provided with a torsion spring, and one torsion leg of the torsion spring presses on the outer side of the lower part of the connecting plate, that is, the upper part of the connecting plate cooperates with the upper part of the pop-up supporting foot, and the lower part of the connecting plate cooperates with the torsion spring, and the other torsion leg of the torsion spring presses on the inner side of the pop-up supporting foot rotatably mounted on the pin shaft, and the lower end of the pop-up supporting foot pops out from between the two side plates and is fixed on the supporting ring. The side plate, the pop-up supporting foot, the pin shaft and the connecting plate together form a fall-stopping device, which leaves the falling hammer and the impact part above the supporting ring to avoid secondary impact; the outer edge of the side plate is located on the pop-up direction of the pop-up supporting foot, and the ring sleeve has a limiting sliding ring, and the inner edge of the limiting sliding ring is provided with a groove. When the torsion spring is compressed, the lower end of the pop-up supporting foot presses on the groove in the limiting sliding ring, that is, the limiting sliding ring constrains the lower end of the pop-up supporting foot to prevent the pop-up supporting foot from popping out under the action of elastic force.

[0010] Specifically, the pop-up support leg includes two completely identical side mounting plates, each of which is provided with mounting holes that cooperate with the pin shaft. The edges of the two side mounting plates are connected by a top pressure plate. The torsion spring is installed between the two side mounting plates, and the torsion foot of the torsion spring is installed on the top pressure plate. When the torsion spring is in a relaxed state, the edge of the side mounting plate presses against the upper part of the connecting plate.

[0011] When in use, the fixed ring and the drop hammer are combined into one, and move downward together and pass through the supporting ring. At this time, the torsion spring is in a compressed state and presses the pop-up support leg outward. The lower end of the pop-up support leg is pressed against the groove in the limit sliding ring and is constrained by the limit sliding ring. The lower end of the pop-up support leg is received between the two side plates. When the drop hammer contacts the test piece, the fixed ring and the drop hammer are bounced up synchronously, and the limit sliding ring overcomes the maximum static friction force under the action of inertia and continues to move downward. At this time, the deceleration effect on the limit sliding ring is much smaller than that on the fixed ring, which causes the limit sliding ring to slide off the pop-up support leg. The pop-up support leg loses the constraint of the limit sliding ring and pops out under the elastic force of the torsion spring. After popping out, the pop-up support leg hangs on the supporting ring fixed on the outside, thereby preventing the device from continuing to move downward and causing a secondary impact.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a device for preventing secondary impact in a drop hammer impact test. The device makes full use of the dynamic performance of the device in the drop hammer impact test. After the drop hammer contacts the test piece, the limit sliding ring and the fixed ring have different deceleration effects, so that the limit sliding ring that originally clamps the support leg falls off, so that the support leg pops out under the action of the spring elastic force and contacts the outermost support ring, thereby preventing it from continuing to move downward to produce a secondary impact. The device is easy to operate, has high safety, and can effectively prevent secondary impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is an overall schematic diagram of the present invention.

[0014] Figure 2 This is a diagram of the triggering process of the present invention, wherein a and b represent the falling process, and c represents the rebound process after departure.

[0015] Figure 3 It is a top view of the present invention.

[0016] Figure 4 This is a schematic diagram of the installation of the fixing ring and side panels.

[0017] Figure 5 A schematic diagram of the structure of the side panel.

[0018] Figure 6 It is a schematic diagram of the structure of the pop-up support.

[0019] Figure 7 It is a structural diagram of the connecting plate.

[0020] Figure 8 The following is a diagram showing the installation of the pop-up feet.

[0021] Fig. 9 Schematic diagram of limit slip ring.

[0022] In the figure: 1-fixed ring, 2-limited sliding ring, 3-support ring, 4-side plate, 5-connecting plate, 6-pop-up support foot, 601-side mounting plate, 602-top pressure plate, 7-pin shaft, 8-torsion spring. DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention are described below in conjunction with the accompanying drawings.

[0024] A device for preventing secondary impact in a drop weight impact test, such as Figures 1 to 9 As shown, it includes an impact part mounted on the outer ring of the drop weight and a support ring 3 arranged above the specimen. In this embodiment, the drop weight and the impact part weigh 566.55 kg in total, of which the drop weight weighs 486.5 kg. If a conventional method is used, it is difficult to pull the drop weight of this weight in time, causing a secondary impact. Even if the drop weight is pulled, it is very easy to cause damage to the equipment. The support ring 3 can be fixed above the specimen restraint device, and the support ring 3 is always kept fixed. There is no restriction on this fixing method. The impact part includes a fixing ring fixed to the outside of the drop weight by a ring sleeve. 1. The fixing ring 1 is fixed to the outer ring of the drop hammer. The outer ring of the fixing ring 1 is provided with a plurality of paired side plates 4. The side plates 4 are provided with 6 pairs. The paired side plates 4 are arranged axially along the fixing ring 1. The side plates 4 are welded to the outer edge of the fixing ring 1, and the side plates 4 are vertical. The diameter of the circle where the outer edge of the side plate 4 is located is smaller than the diameter of the support ring 3, that is, the impact part can pass through the support ring 3. A connecting plate 5 is fixed between the two paired side plates. A pin shaft 7 is provided between the two paired side plates 4, that is, a pin shaft hole is opened at the same position of the two side plates 4, and the pin shaft 7 Pass through the pin hole, install the torsion spring 8 and the pop-up leg 6 through the pin 7, the pin 7 is sleeved with a torsion spring 8, and one torsion leg of the torsion spring 8 presses on the outer side of the lower part of the connecting plate 5, that is, the upper part of the connecting plate 5 cooperates with the upper part of the pop-up leg 6, and the lower part of the connecting plate 5 cooperates with the torsion spring 8. In this embodiment, the upper part of the connecting plate 5 and the lower part of the connecting plate 5 form an obtuse angle, and the other torsion leg of the torsion spring 8 presses on the inner side of the pop-up leg 6 rotatably mounted on the pin 7, and the lower end of the pop-up leg 6 pops out from between the two side plates 4. Fixed on the support ring 3, the side plate 4, the pop-up support leg 6, the pin shaft 7 and the connecting plate 5 together form a fall-stopping device, which keeps the falling hammer and the impact part above the support ring 3 to avoid secondary impact; the outer edge of the side plate 4 is located on the pop-up direction of the pop-up support leg 6 and is surrounded by a limiting slide ring 2, and the inner edge of the limiting slide ring 2 is provided with a groove. When the torsion spring 8 is compressed, the lower end of the pop-up support leg 6 is pressed against the groove in the limiting slide ring 2, that is, the limiting slide ring 2 constrains the lower end of the pop-up support leg 6 to prevent the pop-up support leg 6 from popping out under the action of elastic force.

[0025] like Figure 8 As shown, the pop-up support leg 6 includes two completely identical side mounting plates 601, and mounting holes that cooperate with the pin shaft 7 are opened on the two side mounting plates 601. The edges of the two side mounting plates 601 are connected by a top pressure plate 602. The torsion spring 8 is installed between the two side mounting plates 601, and the torsion foot of the torsion spring 8 is installed on the top pressure plate 602. When the torsion spring 8 is in a relaxed state, the edge of the side mounting plate 601 presses against the upper part of the connecting plate 5.

[0026] When in use, the fixed ring 1 and the drop hammer are combined into one, and move downward together and pass through the support ring 3. At this time, the torsion spring 8 is in a compressed state and presses the pop-up support leg 6 outward. The lower end of the pop-up support leg 6 is pressed in the groove in the limiting slide ring 2 and is constrained by the limiting slide ring 2. The lower end of the pop-up support leg 6 is received between the two side plates 4. When the drop hammer contacts the test piece, the fixed ring 1 and the drop hammer are bounced up synchronously, and the limiting slide ring 2 overcomes the maximum static friction force under the action of inertia and continues to move downward. At this time, the deceleration effect on the limiting slide ring 2 is much smaller than that on the fixed ring 1, which causes the limiting slide ring 2 to slide off the pop-up support leg 6. The pop-up support leg 6 loses the constraint of the limiting slide ring 2 and pops out under the elastic force of the torsion spring 8. After popping out, the pop-up support leg 6 hangs on the support ring 3 fixed on the outside, thereby preventing the device from continuing to move downward and causing a secondary impact.

[0027] The scope of protection claimed by the present invention is not limited to the above specific embodiments. For those skilled in the art, the present invention may have various deformations and changes. Any modifications, improvements and equivalent substitutions made within the concept and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A device for preventing secondary impact in a drop weight impact test, characterized in that: The invention comprises an impact part mounted on the outer ring of a drop weight and a support ring (3) arranged above the test piece, wherein the impact part comprises a fixed ring (1) fixed on the outside of the drop weight, the fixed ring (1) is provided with a plurality of paired side plates (4) on the outer ring, the diameter of the circle where the outer edges of the side plates are located is smaller than the diameter of the support ring (3), a connecting plate (5) is fixed between the two paired side plates, a pin (7) is provided between the two paired side plates (4), a torsion spring (8) is sleeved on the pin (7), one torsion foot of the torsion spring (8) presses against the outer side of the lower part of the connecting plate (5), the other torsion foot of the torsion spring (8) presses against the inner side of a pop-up support leg (6) rotatably mounted on the pin (7), and the lower end of the pop-up support leg (6) pops out from between the two side plates (4) and is fixed on the support ring (3); the outer edge of the side plate (4) is sleeved with a limiting sliding ring (2) in the pop-up direction of the pop-up support leg (6).

2. The device for preventing secondary impact in a drop weight impact test according to claim 1, characterized in that: The inner edge of the limiting sliding ring (2) is provided with a groove, and when the torsion spring (8) is in a compressed state, the lower end of the pop-up support foot (6) is pressed into the groove in the limiting sliding ring (2).

3. The device for preventing secondary impact in a drop weight impact test according to claim 1, characterized in that: The upper portion of the connecting plate (5) cooperates with the upper portion of the pop-up support foot (6), and the lower portion of the connecting plate (5) cooperates with the torsion spring (8).

4. The device for preventing secondary impact in a drop weight impact test according to claim 1, characterized in that: The pop-up support leg (6) comprises two identical side mounting plates (601), the two side mounting plates (601) are provided with mounting holes that cooperate with the pin shaft (7), the edges of the two side mounting plates (601) are connected via a top pressure plate (602), the torsion spring (8) is installed between the two side mounting plates (601), and the torsion foot of the torsion spring (8) is installed on the top pressure plate (602).

5. The device for preventing secondary impact in a drop weight impact test according to claim 4, characterized in that: When the torsion spring (8) is in a relaxed state, the edge of the side mounting plate (601) presses against the upper portion of the connecting plate (5).

6. The device for preventing secondary impact in a drop weight impact test according to claim 1, characterized in that: The side plates (4) are provided in six pairs, and the paired side plates (4) are arranged axially along the fixing ring (1).

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