Device for measuring retention force of core rod of self-plugging rivet

Abstract

The invention discloses a self-plugging rivet mandrel retention force measuring device in the technical field of testing, the self-plugging rivet mandrel retention force measuring device comprises a base and a connecting plate used for riveting a self-plugging rivet, a cavity is formed in the base, a supporting plate is vertically connected in the cavity in a sliding mode, and an ejector rod is detachably connected to the supporting plate; a lifting mechanism for driving the supporting plate to lift is arranged in the base; a groove is formed in one side of the base, the length and the width of the groove are not smaller than those of the connecting plate, the height of the groove is larger than or equal to the thickness of the connecting plate riveted with the self-plugging rivet, a discharging hole communicated with the groove is formed in the top of the base, the hole diameter of the discharging hole is larger than the length of the bulge, and a guide hole communicated with the cavity is formed in the wall body of the bottom of the groove. And the guide hole, the discharge hole and the ejector rod are coaxial. The measuring device can ensure that the ejector rod abuts against the axis of the core rod, so that the measuring precision is improved.

Description

Technical Field

[0001] The invention belongs to the field of detection technology, and in particular relates to a device for measuring the core rod holding force of a blind rivet. Background Art

[0002] Blind rivets, also known as pull rivets or blind rivets, are a common fastener used to connect two or more materials. They are particularly suitable for single-sided operations, that is, they can only be installed from one side of the workpiece. Blind rivets consist of two parts: a hollow rivet body (usually made of metal) and a mandrel (also called a nail rod) that passes through the center of the rivet body. During the installation process, a special rivet gun is used to pull the mandrel, causing the rivet body to expand and firmly fix to the material being connected, while the mandrel will be broken off, leaving a smooth rivet head.

[0003] In order to verify the quality of blind rivets, it is generally necessary to measure the holding force of their core rods. The specific operation is: first, rivet the core rods, and use a special rivet gun to pull the core rods inside the blind rivets to achieve riveting. During this process, the sleeve at the blind end of the blind rivet will expand and form a bulge on one side of the connected materials, thereby fastening these materials. Finally, after the core rod is fully pulled in, a mechanism called a "locking ring" is used to press the locking ring into the conical space formed by the sleeve and the core rod, forming a structure similar to a "safety lock" to ensure that the core rod and the sleeve are tightly combined into one. Then measure the holding force of the blind rivet after riveting. During the measurement, a certain axial thrust is applied to the core rod to try to push it out of the body of the blind rivet. When the external force reaches a certain threshold and exceeds the maximum deformation resistance that the locking ring can withstand, if the core rod begins to loosen, it means that the product cannot meet the design requirements, that is, failure has occurred.

[0004] For example, the patent with the authorization announcement number "CN 114414118 B" discloses a tooling for measuring the core rod retention force of a blind rivet. During the test, the mounting plate with the blind rivet installed is placed horizontally on the push-out base of the corresponding specifications to ensure that the installed blind rivet bulge and the core rod head can be smoothly placed in the groove and positioning hole of the base. Then the guide sleeve is placed in the test base to make the base, the mounting plate and the guide sleeve tightly combined. After the guide sleeve is placed in the base, the guide sleeve is aligned with the left and right edges of the base to ensure that there is no misalignment between the guide sleeve and the base. Then, the ejector rod of the corresponding specifications is selected and inserted into the hole above the protective cover. At this time, the ejector rod and the core rod section of the tested blind rivet can be completely aligned, solving the problem of inaccurate alignment caused by the previous adjustment with the naked eye and the tilt of the ejector rod when pressure is applied. Then the installed tooling assembly is placed in the center of the pressure plate of the tensile testing machine, and a preload force of 100N to 200N is applied to prevent the tooling assembly from shaking after being placed in the pressure plate to affect the alignment. The test plan is set up for the test, and the test result reads the maximum force value before the curve drops. This tooling can well measure the holding force of the core rod of the blind rivet, but there are the following problems: 1. After the blind rivet is riveted on the mounting plate, the installation process with the ejector rod, guide sleeve and base requires manual operation, and the process is relatively complicated. 2. During installation, in order to facilitate the blind rivet to smoothly enter the groove and positioning hole, the aperture of the groove and positioning hole will be slightly larger than the blind rivet; at the same time, in order to allow the ejector rod to smoothly enter the guide hole, the aperture of the guide hole will also be slightly larger than the ejector rod diameter; and there will also be a gap between the opposite surfaces of the guide sleeve and the base. Under the cumulative effect of the three, it is difficult to ensure that the rod diameter of the ejector rod is completely coaxial with the core rod of the blind rivet by manual operation, which will cause the core rod to be offset when it is ejected. 3. An external ejection mechanism is required to act on the ejector rod to eject the core rod. In the process of transferring the blind rivet, the core rod and the ejector rod will further be non-coaxial, which will further affect the measurement accuracy. Summary of the invention

[0005] The present invention is intended to provide a device for measuring the core rod holding force of a blind rivet, so as to ensure that a push rod is held against the axis of the core rod, thereby improving the measurement accuracy.

[0006] A device for measuring the core rod retention force of a blind rivet in the present scheme comprises a base and a connecting plate for riveting the blind rivets, a cavity is provided in the base, a support plate is vertically slidably connected in the cavity, and a push rod is detachably connected to the support plate; a lifting mechanism is provided in the base for driving the support plate to rise and fall; a groove is provided on one side of the base, the length and width of the groove are not less than the length and width of the connecting plate, the height of the groove is ≥ the thickness of the connecting plate after the blind rivet is riveted, a discharge hole connected to the groove is provided on the top of the base, the aperture of the discharge hole is larger than the length of the bulge, and a guide hole connected to the cavity is provided on the wall at the bottom of the groove, and the guide hole, the discharge hole and the push rod are coaxial.

[0007] The working principle and beneficial effects of this scheme: When in use, first rivet the blind rivet on the connecting plate, and then put the connecting plate into the groove on one side of the base. Since the length and width of the groove are not less than the length and width of the connecting plate, when placing the riveted connecting plate, ensure that one side of the connecting plate is against the side wall of one side of the groove, and push the connecting plate to the side of the groove away from its opening. At this time, the guide hole, the discharge hole, the core rod and the push rod are coaxial, and the height of the groove is ≥ the thickness of the connecting plate after riveting the blind rivet, so that the connecting plate can be stably placed in the groove. Then the support plate is driven up by the lifting mechanism in the base. Since the guide hole, the discharge hole and the self are coaxial, the push rod can accurately resist the core rod axis of the blind rivet. When it is necessary to measure the core rod holding force, apply axial thrust to the push rod and try to push the core rod out of the main body of the blind rivet. The quality of the blind rivet is judged by reading the force value when the core rod begins to loosen when the external force reaches a certain threshold.

[0008] Beneficial effects: The ejector rod is ensured to be against the axis of the core rod, thereby improving the measurement accuracy. The problem of the core rod being offset when ejected due to the difficulty in ensuring the ejector rod and the core rod are coaxial is avoided, thereby making the measurement result more accurate and reliable. The installation process is simplified. Compared with the prior art, there is no need for complicated manual installation operations, thereby improving work efficiency.

[0009] Furthermore, a protective frame is provided on the top of the base, which can play a protective role and prevent the blind rivet from flying out due to being pushed out by the ejector rod during the measurement process, thereby improving the safety of the operation.

[0010] Furthermore, one side of the protection frame is a protection net, which can not only play a certain protective role, but also facilitate the operator to observe the measurement process and understand the measurement situation in time.

[0011] Furthermore, two first guide rods are provided on the side wall of the base, and the two first guide rods are respectively located on both sides of the groove, and guide grooves are provided on the tops of the two opposite sides of the two first guide rods, and the distance between the two guide grooves is not less than the width of the connecting plate. The first guide rods and the guide grooves can guide the insertion of the connecting plate, ensuring that the connecting plate can be accurately inserted into the groove, thereby improving the accuracy and efficiency of the operation.

[0012] Furthermore, two second guide rods are provided on the side wall of the base, the distance between the two second guide rods is smaller than the distance between the two first guide rods, the first guide rod is located below the second guide rod, and the height difference between the first guide rod and the second guide rod is equal to the thickness of the brim of the blind rivet. The second guide rod can support and guide the brim of the blind rivet, further improving the stability of the blind rivet during the measurement process.

[0013] Furthermore, the two second guide rods are fixedly connected with a semicircular fixing part, the inner diameter of which is equal to the diameter of the brim of the blind rivet, a push block is slidably connected between the two guide grooves, the push block is "L" shaped and the open end faces the groove, and a notch is provided at the connection between the connecting plate and the side of the push block, and the notch makes the outer wall of the side of the push block and the outer wall of the connecting plate in the same vertical plane. The fixing part can better fix the brim of the blind rivet, and the push block can easily push the connecting plate into the groove, thereby improving the convenience of operation.

[0014] Furthermore, a power mechanism for driving the push block to slide is provided on the base, and the power mechanism can automatically push the push block without manual operation, thereby further improving work efficiency.

[0015] Furthermore, the lifting mechanism and the power mechanism are respectively a first hydraulic cylinder and a second hydraulic cylinder. The hydraulic cylinder has the advantages of good stability and strong power, can ensure the accurate movement of the push rod and the push block, and improve the accuracy and reliability of the measurement.

[0016] Furthermore, an "L"-shaped fixing plate is fixedly connected to the extension and retraction rod of the second hydraulic cylinder, and the fixing plate is slidably connected to the connecting rod at one end away from the second hydraulic cylinder. The sliding direction of the connecting rod is parallel to the width direction of the groove, and the sliding direction of the push block is consistent with the length direction of the groove. The fixing plate is used to fix the locking piece of the connecting rod. Through the setting of the connecting rod, the position of the push block can be adjusted by sliding the connecting rod. On the one hand, when the distance between the guide grooves is greater than the connecting plate, it can be ensured that the connecting plate does not deviate during the movement process, thereby ensuring that the core rod of the blind rivet is coaxial with the push rod. Since the distance between the two guide grooves is greater than the push block, rigid friction between the two is avoided.

[0017] Furthermore, the locking member is a screw. The screw as the locking member has a simple structure, is easy to operate, and can reliably fix the position of the connecting rod.

[0018] In the present application, the thickness of the connecting plate after riveting with blind rivets refers to the thickness of the connecting plate plus the thickness of the blind rivets on both sides thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of a blind rivet core rod retention force measuring device according to Embodiment 1 of the present invention;

[0020] Figure 2 This is a schematic structural diagram of a device for measuring the core rod holding force of a blind rivet according to Example 2 of the present invention. DETAILED DESCRIPTION

[0021] The following is further described in detail through specific implementation methods:

[0022] The figure marks in the drawings of the specification include: base 1, first hydraulic cylinder 2, support plate 3, cavity 4, push rod 5, second guide rod 6, fixing part 7, first guide rod 8, push block 9, connecting rod 10, fixing plate 11, guide groove 12, groove 13, discharge hole 14, protection frame 15, protection net 16.

[0023] Embodiment 1 is basically as attached Figure 1 As shown: A device for measuring the core rod holding force of a blind rivet comprises a base 1 and a connecting plate for riveting the blind rivets, wherein a cavity 4 is arranged in the base 1, a supporting plate 3 is vertically slidably connected in the cavity 4, and a push rod 5 is detachably connected to the supporting plate 3; a first hydraulic cylinder 2 is installed in the base 1, and the free end of the lifting and retracting rod of the first hydraulic cylinder 2 is fixedly connected to the bottom of the supporting plate 3; a groove 13 is arranged on the right side of the base 1, the length of the groove 13 is greater than the length of the connecting plate, and the width of the groove 13 is slightly greater than the width of the connecting plate, so as to facilitate the sliding connection Connecting plate; the height of the groove 13 is greater than the thickness of the connecting plate after riveting with the blind rivet, the top of the base 1 is provided with a discharge hole 14 connected with the groove 13, the aperture of the discharge hole 14 is greater than the length of the bulge and smaller than the width of the connecting plate, and a guide hole connected with the cavity 4 is provided on the wall at the bottom of the groove 13, the guide hole, the discharge hole 14 and the push rod 5 are coaxial, when the rear side of the connecting plate is abutted against the rear side wall of the groove 13, and the left side of the connecting plate is abutted against the side wall of the left side of the groove 13, the core rod of the blind rivet is coaxial with the push rod 5.

[0024] Two first guide rods 8 are provided on the right side wall of the base 1, and the two first guide rods 8 are respectively located on both sides of the groove 13. Guide grooves 12 are provided on the tops of the opposite sides of the two first guide rods 8. The distance between the two guide grooves 12 is not less than the width of the connecting plate, and the distance between the two guide grooves 12 is equal to the width of the groove 13.

[0025] Two second guide rods 6 are also provided on the right side wall of the base 1. The distance between the two second guide rods is smaller than the distance between the two first guide rods 8. The first guide rod 8 is located below the second guide rod 6. The height difference between the first guide rod 8 and the second guide rod 6 is equal to the thickness of the brim of the blind rivet. The two second guide rods 6 are fixedly connected with the same semicircular fixing part 7. The inner diameter of the fixing part 7 is equal to the diameter of the brim of the blind rivet. A push block 9 is slidably connected between the two guide grooves 12. The push block 9 is "L"-shaped and the open end faces the groove 13. A notch is provided at the connection between the connecting plate and the side of the push block 9. The notch makes the outer wall of the side of the push block 9 and the outer wall of the connecting plate in the same vertical plane.

[0026] A second hydraulic cylinder is installed on the rear side wall of the base 1. The second hydraulic cylinder is horizontally arranged. An "L"-shaped fixing plate 11 is fixedly connected to the lifting and retracting rod of the second hydraulic cylinder. The fixing plate 11 is slidably connected to the connecting rod 10 at one end away from the second hydraulic cylinder. The sliding direction of the connecting rod 10 is parallel to the width direction of the groove 13, and the sliding direction of the push block 9 is consistent with the length direction of the groove 13. The fixing plate 11 is used to fix the screws of the connecting rod 10.

[0027] The specific implementation process is as follows: first, place the brim of the blind rivet between the first guide rod 8 and the second guide rod 6, and make the brim abut against the fixing part 7; then abut one end of the connecting plate against the push block 9, and adjust the connecting rod 10 so that the side of the push block 9 abuts against the notch of the connecting plate, and the rear end of the connecting plate abuts against the side wall of the guide groove 12. At this time, the core rod of the blind rivet is coaxial with the mounting hole on the connecting plate, and the rear side wall of the connecting plate and the rear side wall of the groove 13 are in the same vertical plane, and then the blind rivet is riveted to the connecting plate by a rivet gun.

[0028] Next, the second hydraulic cylinder drives the fixing plate 11, the connecting rod 10 and the push block 9 to slide the connecting plate along the guide groove 12 toward the groove 13. During the sliding process, due to the guiding effect of the push block 9 and the guide groove 12, the connecting plate can enter the groove 13 more accurately until the left end of the connecting plate abuts against the left side wall of the groove 13, ensuring that the core rod of the blind rivet is coaxial with the push rod 5.

[0029] Then, the first hydraulic cylinder 2 in the base 1 is started, and the lifting rod of the first hydraulic cylinder 2 pushes the support plate 3 to rise. Since the guide hole, the discharge hole 14 and the push rod 5 are coaxial, the push rod 5 on the support plate 3 will accurately abut against the core rod axis of the blind rivet.

[0030] When the core rod holding force measurement is required, an axial thrust is applied to the ejector rod 5 to try to push the core rod out of the blind rivet body. The quality of the blind rivet can be judged by reading the force value at which the core rod begins to loosen when the external force reaches a certain threshold.

[0031] Embodiment 2 is basically as attached Figure 2 As shown, the only difference between it and embodiment 1 is that a protection frame 15 is provided on the top of the base 1 ; and one side of the protection frame 15 is a protection net 16 .

[0032] The difference between Example 3 and Example 2 is that a plc controller is also provided on the base 1, and the plc controller is connected to the first hydraulic cylinder 2 and the second hydraulic cylinder through electrical signals, and the plc controller is used to control the on / off and extension and retraction of the first hydraulic cylinder 2 and the second hydraulic cylinder. By controlling the first hydraulic cylinder 2 and the second hydraulic cylinder through the plc controller, the retention force of the core rod of the blind rivet can be measured more accurately.

[0033] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. In this application, the description of front, back, left and right is only based on the drawings to better explain the device, which is convenient for readers to understand, and is not a limitation on the position. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A device for measuring the core rod holding force of a blind rivet, comprising a base and a connecting plate for riveting blind rivets, characterized in that: A cavity is provided in the base, in which a support plate is vertically slidably connected, and a push rod is detachably connected to the support plate; a lifting mechanism is provided in the base to drive the support plate to rise and fall; a groove is provided on one side of the base, the length and width of the groove are not less than the length and width of the connecting plate, and the height of the groove is ≥ the thickness of the connecting plate after riveting with blind rivets, a discharge hole connected to the groove is provided on the top of the base, the aperture of the discharge hole is larger than the length of the bulge, and a guide hole connected to the cavity is provided on the wall at the bottom of the groove, and the guide hole, the discharge hole and the push rod are coaxial.

2. A blind rivet core rod holding force measuring device according to claim 1, characterized in that: A protective frame is arranged on the top of the base.

3. A blind rivet core rod holding force measuring device according to claim 2, characterized in that: One side of the protection frame is a protection net.

4. A blind rivet core rod retention force measuring device according to any one of claims 1 to 3, characterized in that: Two first guide rods are arranged on the side wall of the base, and the two first guide rods are respectively located on both sides of the groove. The tops of the two opposite sides of the two first guide rods are provided with guide grooves, and the distance between the two guide grooves is not less than the width of the connecting plate.

5. A blind rivet core rod holding force measuring device according to claim 4, characterized in that: Two second guide rods are also provided on the side wall of the base, the distance between the two second guide rods is smaller than the distance between the two first guide rods, the first guide rod is located below the second guide rod, and the height difference between the first guide rod and the second guide rod is equal to the thickness of the brim of the blind rivet cap.

6. A blind rivet core rod retention force measuring device according to claim 5, characterized in that: The two second guide rods are fixedly connected with a semicircular fixing part, the inner diameter of which is equal to the diameter of the brim of the blind rivet cap, and a push block is slidably connected between the two guide grooves, the push block is "L" shaped and the open end faces the groove, and a notch is provided at the connection between the connecting plate and the side of the push block, and the notch makes the outer wall of the side of the push block and the outer wall of the connecting plate in the same vertical plane.

7. A blind rivet core rod retention force measuring device according to claim 6, characterized in that: The base is provided with a power mechanism for driving the push block to slide.

8. A blind rivet core rod holding force measuring device according to claim 7, characterized in that: The lifting mechanism and the power mechanism are respectively a first hydraulic cylinder and a second hydraulic cylinder.

9. A blind rivet core rod holding force measuring device according to claim 8, characterized in that: An "L"-shaped fixing plate is fixedly connected to the extension and retraction rod of the second hydraulic cylinder. The fixing plate is slidably connected to the connecting rod at one end away from the second hydraulic cylinder. The sliding direction of the connecting rod is parallel to the width direction of the groove, and the sliding direction of the push block is consistent with the length direction of the groove. The fixing plate is used to fix the locking piece of the connecting rod.

10. A blind rivet core rod holding force measuring device according to claim 9, characterized in that: The locking member is a screw.

Images