Universal lathe tool that performs tests on a specimen

Abstract

The present invention relates to a universal lathe tool that performs tests on a specimen to measure its resistance and acts as a three-point pre-cracking machine using the inherent strength of a lathe. The tool is adapted by coupling the same to the main carriage of the lathe and it uses its driving force to exert an eccentric rotation on a spindle comprising a bearing that propagates the vibration towards the tool structure, causing the three points to exert pressure on a specimen on which resistance is measured.

Description

[0001] TOOL FOR UNIVERSAL LATHE THAT ALLOWS TESTING ON A TEST TEST

[0002] PREVIOUS ART

[0003] There are various types of equipment available for performing strength tests on specimens, requiring knowledge of their behavior under various loads, both compressive and tensile. Most of this equipment is not self-contained, and its cost is considerable, making it a difficult resource for certain entities with limited budgets, such as universities, institutes, and research centers that lack sufficient resources.

[0004] For the reasons explained above, many of these centers are unable to pre-crack specimens, which are subsequently required to evaluate the stable crack growth toughness of materials through fracture mechanics testing. This problem arises from the lack of availability of adequate machinery to perform this type of testing.

[0005] Among the equipment commonly used in the prior art, we can mention document US4335615, which describes equipment for testing materials to detect the effects of stress corrosion cracking, which includes more than two tensioning units, each consisting of a base plate, two guide bars, an upper and lower cross beam, and a locking system for the lower cross guide. A beam and a connecting flange between the cross beam and a threaded bar cause the elongation of a test sample. The motor power block drives the threaded bar. A motor power unit is included in the power supply block, and a vertically sliding gear is inserted between the motor gear and the block. The motor power unit consists of two stepper motors that drive planetary gears.The planets drive planetary gears, which, by means of an arm, drive the drive shaft operatively connected to the threaded rod. In particular, the invention relates to equipment with six tensioning units comprising a means for automatically disconnecting the limit switch and a lifting system in the power supply block to separate the transmission gears from the rest of the system.

[0006] The angular speed of the stepper motors can be controlled by an electrically generated step frequency, the control unit being composed, if desired, of a microprocessor and memory.

[0007] US5263373 describes a tool that applies force to a test piece arranged between a table and a crosshead by means of rotation of a screw shaft in a nut at each end of the crosshead. The shaft is rotatably supported by upper and lower bearings that are coupled by the rod and vertically movable by the cylinder to equalize the length of the sample. The lower end of the shaft is received in a sleeve at the upper end of a drive shaft so that it is extensible and retractable and in any vertical position can be held in the sleeve by a clamp to allow the shaft to move when rotated by the shaft. US5598738 describes a compact bolt-loaded tensile specimen loading apparatus including: a) a body having first and second opposite longitudinal ends,the first end comprising an externally threaded portion sized to be threadably received within the threaded opening of the specimen; b) a longitudinal loading rod having first and second opposite longitudinal ends, the loading rod being slidably received in a longitudinal direction within the body internally through the externally threaded portion and extending longitudinally slidably outwardly from the first longitudinal end of the body; c) a force-sensitive transducer slidably received within the body and positioned to engage relative to the second longitudinal end of the loading rod; and d) a loading bolt threadably received relative to the body,the load bolt having an end bearing surface and being positioned to bear against the transducer to forcibly sandwich the transducer between the load bolt and the load rod. A method for determining in situ the applied force during crack propagation in a bolt-loaded compact tension test specimen is also described.

[0008] Both the cited documents and the equipment available on the market for testing specimens and measuring their strength follow the same testing principle, but all of these devices have their own power source to activate the mechanisms that apply the pressure required to perform the test on a specimen. None of them teaches or suggests a tool that can be adapted to a universal lathe to perform a material strength test on a specimen, where the tool uses the driving force and the robustness of the specimen to activate the tool's mechanisms and apply the force for the test at three points of contact.

[0009] The invention relates to a versatile tool capable of performing three-point pre-cracking of specimens, used in fracture mechanics tests to evaluate the stable crack growth toughness of materials. It features an adjustable body that allows efficient adjustment to various specimen sizes. In addition, an electronic measurement system is incorporated to record the applied load and the number of rotations performed, in order to obtain precise data on the applied cycles necessary to achieve the desired crack size. This electronic system consists of a set of sensors, all of which are controlled in an integrated manner by a microcontroller.

[0010] BR EV E DESCRIPTION OF THE FIGURES

[0011] Figure 1: represents a front view of the structural frame and the components of the tool that adapts to universal lathes to perform strength tests on specimens.

[0012] Figure 2: represents an isometric view of the support pillar where the structural frame of the tool that adapts to universal volumes is secured.

[0013] Figure 3: Shows a bottom isometric view of the structural frame and components of the tool that adapts to universal volumes for performing strength tests on specimens. Figure 4: Shows an isometric view of the tool installed in a universal volume, also showing the spindle and eccentric bearing for exerting force on the three points acting on a specimen.

[0014] Figure 5: represents a close-up isometric view showing in detail the tool installed in a universal screw, in which the spindle and the eccentric rotating bearing can also be seen to exert force on the three points acting on a test piece.

[0015] Figure 6: represents a close-up isometric view showing in detail the spindle and eccentric bearing, as well as the lower pressure point on a specimen.

[0016] Figure 7: represents a close-up isometric view showing in detail the spindle and eccentric bearing, as well as the three pressure points on a specimen.

[0017] Figure 8: represents an isometric view from above of the tool mounted on a universal screw.

[0018] Figure 9: represents an isometric view of the detail of the spindle and the eccentric bearing that are part of the tool.

[0019] DESCRIPTION OF THE INVENTION

[0020] The invention consists of a tool that adapts to universal chucks to perform tests on specimens to measure their strength and acts as a three-point pre-cracking device, taking advantage of the inherent solidity of a lathe. The tool is comprised of a support pillar to which a structural frame is secured, which has a horizontal base, two vertical lateral ends, and a horizontal beam arranged between the vertical lateral ends. Two upper support points are attached to the lower surface of the horizontal beam, each with pointed ends and oriented toward the horizontal base of the structural frame. In the upper area of ​​the horizontal base, a lower support point is arranged that points toward the horizontal beam, facing the upper support points arranged on the lower surface of the horizontal beam.In this way, three support points are formed that will apply pressure to a test piece, allowing its resistance to be measured and pre-cracked.

[0021] The support pillar is attached to the main carriage of a universal tome by means of adjusting bolts.

[0022] The horizontal base of the structural frame includes a hole through which a threaded bolt passes, onto which the lower support point is installed. The threaded bolt allows the lower support point, located in the upper area of ​​the horizontal base, to be moved vertically. This vertical movement allows the support point to be adjusted to the desired height, allowing a specimen to be secured within the structural frame. The specimen is held by both the lower support point and the two upper support points, i.e., it is secured at three points.

[0023] The tool also comprises a spindle that has a load-transmitting bearing at one end, while the free end of the spindle is connected to the lathe chuck and universal joint that provides the driving force to cause the spindle and load-transmitting bearing to rotate.

[0024] The head of the threaded bolt has a curved plate incorporated which is designed to be in contact with the load transmitting bearing that is incorporated in the spindle. The load transmitting bearing rotates eccentrically caused by the universal screw plate, such that when the screw is activated, the eccentric rotation of the universal screw plate is transmitted to the load transmitting bearing and causes a force on the curved plate that is transmitted to the lower support point, consequently acting on the specimen, which, being also imprisoned to the upper support points, is subjected to pressure at the three support points, the two upper ones and the lower one, and thus being able to carry out the resistance test on the specimen until it causes a pre-crack.

[0025] The tool also includes an electronic system capable of measuring the load applied to the specimen and recording the rotations of the universal test plate. To achieve this, the system comprises a set of sensors, all controlled in an integrated manner by a microcontroller.

[0026] With this tool, the universal tome has been transformed into a highly functional and efficient pre-cracker for generating fatigue cracks in three-point bending specimens.

[0027] In summary, the universal tomo tool as a three-point bending pre-cracker represents an innovative solution for fatigue crack generation. DETAILED DESCRIPTION OF THE INVENTION

[0028] The tool (1) that is coupled to a universal volume (17) to carry out tests on a test piece (8) and thus measure its resistance until causing a pre-crack, is composed of a support pillar (14) on which a structural frame is secured that has a horizontal base (3), two vertical lateral ends

[0029] (2) and a horizontal beam (4) arranged between the vertical lateral ends (2). The horizontal beam (4) comprises two upper support points (5) that have pointed ends and are oriented towards the horizontal base.

[0030] (3) of the structural frame. The upper horizontal base area (3) comprises a lower support point (6) pointing towards the horizontal beam (4), facing the upper support points (5) arranged on the lower surface of the horizontal beam (4). The three support points will apply pressure on the test piece (8) and thus measure its resistance until pre-cracking occurs.

[0031] The support pillar (14) is coupled to the main carriage (16) of the universal tome (17) by means of adjustment bolts, for which the support pillar comprises a base plate (18) provided with holes (15) through which the adjustment bolts that fit the main carriage (16) pass. The support pillar (14) also comprises a structural rib (19) to give it rigidity and withstand the force generated by the plate (13) of the universal tome (17).

[0032] The horizontal base (3) of the structural frame comprises a hole through which a threaded bolt (7) passes, the tip of which comprises the lower support point (6). The threaded bolt (7) allows the lower support point (6) included in the upper area of ​​the horizontal base (3) to move vertically.

[0033] The tool also comprises a spindle (12) that at one of its ends has a load transmitting bearing (10), while the free end of the spindle (12) is the one that is connected to the plate (13) of the universal lathe (17) and that provides the driving force to cause the spindle (12) and the load transmitting bearing (10) to rotate.

[0034] The head of the threaded bolt has a curved plate (9) incorporated which is in contact with the load transmitting bearing (10) comprising the spindle (12). The load transmitting bearing (10) rotates eccentrically (11), where said eccentric movement is caused by the plate (13) of the universal screw (17), so that when the lathe is activated, the eccentric rotation of the plate (13) of the universal screw (17) is transmitted to the load transmitting bearing (10) exerting force and vibration on the curved plate (9) which is transmitted to the lower support point (6) and consequently on the test piece (8), which is also imprisoned by the upper support points (5).

[0035] The tool also includes an electronic system capable of measuring the load applied to the specimen and recording the rotations of the universal test plate. To achieve this, the system comprises a set of sensors, all controlled in an integrated manner by a microcontroller.

Claims

MODIFIED CLAIMS received by the International Bureau on 24 March 2025 (24.03.2025) 1. Tool for a universal lathe that allows testing a specimen to be carried out to measure its resistance and acts as a three-point pre-cracking tool, taking advantage of the inherent solidity of a lathe, which is composed of a support pillar (14) comprising a structural frame secured to said support pillar (14), wherein said structural frame comprises a horizontal base (3), two vertical lateral ends (2) and a horizontal beam (4) arranged between the vertical lateral ends (2); which comprises a spindle (12) that at one of its ends comprises a load transmitting bearing (10), while the free end of the spindle (12) is connected to the plate (13) of the universal lathe (17) and which provides the driving force to cause the rotation of the spindle (12) and the load transmitting bearing (10), which is in contact with a base plate. (9) arranged on the head of said threaded bolt (7); CHARACTERIZED in that the horizontal beam (4) comprises two upper support points (5) that have pointed ends and are oriented pointing towards the horizontal base (3) of the structural frame; in that the upper area of ​​the horizontal base (3) comprises a lower support point (6) that points towards the horizontal beam (4), facing the upper support points (5) arranged on the lower surface of the horizontal beam (4), such that the three support points apply pressure on a test piece (8); in where the horizontal base (3) of the structural frame comprises a hole through which a threaded bolt (7) passes, at the tip of which it comprises said lower support point (6); said support pillar (14) being coupled to the main carriage (16) of the universal lathe (17).

2. Tool for a universal lathe that allows testing to be carried out on a test piece according to claim 1, CHARACTERIZED in that said support pillar (14) is coupled to the main carriage (16) of the universal lathe (17) by means of adjustment bolts.

3. Tool for a universal lathe that allows testing to be carried out on a test piece according to claim 2, CHARACTERIZED in that said support pillar (14) comprises a base plate (18) provided with holes (15) through which adjustment bolts pass that fit the main carriage (16).

4. Tool for a universal lathe that allows testing to be carried out on a test piece according to claim 3, CHARACTERIZED in that said support pillar (14) also comprises a structural rib (19).

5. Tool for a universal lathe that allows testing to be carried out on a test piece according to claim 1, CHARACTERIZED in that said horizontal base (3) comprises a hole through which It passes through a threaded bolt (7) that comprises said lower support point (6).

6. Tool for a universal lathe that allows testing to be carried out on a test piece according to claim 1, CHARACTERIZED in that it also comprises an electronic system that comprises a set of sensors and a microcontroller.

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