WO2017015773A1

WO2017015773A1 - Nut shearing device

Info

Publication number: WO2017015773A1
Application number: PCT/CL2016/050041
Authority: WO
Inventors: Jose Antonio Vallejo Rodriguez; Jose Antonio VALLEJO ARANDA
Original assignee: Abasolo Vallejo S.A.
Priority date: 2015-07-29
Filing date: 2016-07-25
Publication date: 2017-02-02
Also published as: PE20180443A1; CL2015002115A1

Abstract

The invention relates to a shearing device (7) for nuts (1) used in high-tonnage machines, such as, for example, mineral grinding mills, said nuts being fitted on bolts (6), with a notch (3) provided on at least two of the sides (2) of each nut. The shearing device comprises a hollow positioning die (10) having a hexagonal outer contour and a hexagonal inner contour. A first inner surface of the hollow positioning die (10) is provided with a groove in the form of a female dovetail (11) for housing a stationary blade (4b) that is inserted into the notches (3) in the nut (1), while a second inner surface thereof, located on the opposite side to the first inner surface, is provided with a hollow cylinder (20) that is inclined in relation to the hollow positioning die (10) and provided with a groove (19) in the front portion thereof, towards the interior of the hollow positioning die (10), said groove (19) having a rectangular cross-section (19) and housing a movable blade (4a). The inclined hollow cylinder (20) is provided internally, in the rear portion of the cavity, with a thread for the coupling of a hydraulic cylinder (21), the front portion of which includes a cylindrical projection (22) having a thread that can be screwed into the inclined hollow cylinder (20). Moreover, the hydraulic cylinder (21) is provided laterally with a connector (23) for receiving a tube from a pump that supplies the hydraulic fluid used to actuate the piston, which is joined, via the cylindrical cavity inside the inclined hollow cylinder (20), to the movable blade (4a) that moves inside the groove (19) with the rectangular cross-section (19) until it reaches the notch (3) in the nut (1).

Description

NUT SHEARING EQUIPMENT

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a nut shearing equipment that has a notch in at least two of its lateral and opposite faces, which are used in high tonnage machines, such as in mineral grinding mills. These mills have in their interior coatings and lifters that are fixed from the inside to their housing by means of screws, and on the outside, said nut is fitted with notches. The objective of this invention is to complement the nut with notches by means of equipment that allows splitting or breaking said nuts, minimizing the time for maintaining the mill for grinding minerals and increasing their availability.

BACKGROUND OF THE INVENTION

In high tonnage machines, such as mineral grinding mills, it is required to periodically stop their operation for the replacement of worn parts or elements. These machines participate in productive processes whose in-depth generates significant losses for the industry, such as the copper industry. That is why it is necessary to reduce the time of such arrests to avoid or minimize such losses.

As an example, currently a SAG mill of a magnitude of 40 feet (12192 mm) in diameter by 20 feet (6096 mm) long has an availability of 90% and more, processes on the order of 100,000 TPD (tons per day), which brings benefits of the order of US $ 100,000.- per hour of production, the change of coatings has an average of about 30 hrs. of activities, of which 10 hrs. only spent on removing bolts and nuts, reducing this time with the use of a quick-release nut would increase availability by at least 5 hrs. with the consequent increase in production reaching benefits of the order of US $ 500,000.- each time the coatings are changed, they can go 2 to 3 times in the year.

The normal operation of a nut or female device (when it is joining the two components that you want to keep together) causes a field of compressive stresses in a functional way in practically the entire nut or female device. This condition of the compressive field, not it allows tension concentrators to present a risk condition that destroys the nut or female device, because it is not possible to propagate a crack within a field of stresses under compression. The previous assertion has been proven both experimentally, carrying out a series of experiments where geometric variables of the notch and variations of the material (Different alloys and conformation of the nut or female device) have been considered; as well as through simulations based on the Finite Element Method. The dimensions of the notch constitute the main characteristic that makes the female nut or device quick to extract, both depths and thicknesses and angles of the notch have been determined, as shown in Figure 1, which are placed in an antagonistic way , and under the action of wedges allow the breakage of the female nut or quick-release device by separating it into two or more parts, as can be seen in Figure 2.

The present invention relates to the equipment that allows the breakage of the nut with notches.

There have been several attempts in the state of the art to obtain equipment that allows the breakage of nuts in different situations. Thus, for example, document CL 42863 discloses an apparatus for the maintenance of semi-autogenous grinding mills used in large-scale mining. Specifically, this document discloses a cold nut cutting apparatus which has a mobile cutting tool and a fixed cutting tool, in which said apparatus is actuated by means of a hydraulic force and is structured by a front body, a rear body and a hydraulic cylindrical chamber located between both bodies. In addition, this tool can be incorporated into a directed or remote handling station for easy operation. This device requires extremely high working pressures and a long time to split the nut, in addition to the fact that a nut as hard as that used in a mineral grinding mill with only one broken side does not come out as easily from the bolt so it is not It meets the goal of time reduction and its positioning is very uncomfortable.

GB 1801772 discloses a device for cutting nuts, which is made up of a concave curved seat to be placed in the nut, and 90 ^s from! center of this seat is located a cutting punch that opens by a end the nut, from the side of it. This type of device can only be used on soft nuts and only by e! side presenting basically the same problems as the previous document.

Document SU 846140 discloses an apparatus for cutting nuts comprising two jaws at whose front ends knives are located for cutting both the upper and lower portions of the nut. It has a punch that in the back, when advancing, closes the jaws. Between both ends of the jaws, there is a spring that allows them to return to their initial position, when the apparatus has made the cut. This device can only be used on soft nuts, since the nuts for which it is designed are nuts that do not require a notch in the outer faces to generate stress concentration. Nor does it have a positioning die that facilitates its operation and reduces time.

Document SU 1461590 discloses an apparatus for cutting nuts by its sides. This apparatus is composed of two jaws at whose front ends knives are located to make the cut in both the upper and lower portion of the nut, hugging said nuts by the side. In the center of the jaws there are pivots that allow them to open and close as a result of a hydraulic system with spring means that act perpendicularly to said jaws. This device cannot be used in mineral grinding mills, because the cutting or breaking of the nut is done by the side of the nut, and also, it is nuts without a notch, so for a joint element from a SAG mill, a lot of pressure would be required to cut it putting safety conditions at risk.

Document SU 1590225 discloses an apparatus for cutting nuts by its sides. This apparatus is composed of two jaws at whose front ends knives are located to make the cut in both the upper and lower portion of the nut, hugging said nuts by the side. The nut is imprisoned by two supports located at the front ends of the jaws, and by a central support that emerges from the pivots, located in the center of the jaws and which allow them to open and close the product of a hydraulic system with means of spring acting perpendicular to said jaws. Also this device cannot be used in grinding mills of minerals, because the cutting or breaking of the nut is done by the side of the nut, and in addition, it is nuts without a notch, so to break an attachment element of a SAG mill an extremely high pressure would be required .

Document SU1292944 discloses a hydraulic hand tool that can be used in various dismantling operations. The purpose of the invention disclosed in this document is to increase productivity by reducing the complete nuts, splitting them into two parts, which allows them to be easily removed from the threaded screws. The apparatus for cutting a nut comprises a housing that is made as a hydraulic cylinder, which has two twin pistons and a return spring. On the piston rod, it ends in a fixed knife that leaves from a housing towards a cavity that houses the nut to be cut, which is coaxially mounted with a second blade. The cutting edges of the blades are designed to face each other. The body that has a nozzle is to feed from a working fluid. When the nut is placed in the cavity between both blades, the pressure supplied to the hydraulic cylinder increases. The knives cut the nut 10 into two parts. After the pistons are depressurized and by the effect of a spring, the piston with the blade returns to its original position. After removing the device the two halves of the threaded nut are removed.

WO 93/00193 discloses a nut splitter that incorporates a cutting blade, the working edge is shaped as a blunt, rounded profile. The blade preferably has the shape of a section of an equilateral triangle, with a cutting edge formed at each vertex, thus allowing the use of a blade holder that allows for easy change of the working edge.

The documents of the prior art mentioned above, describe shearing equipment that require very high operating pressures, because they are designed to cut solid nuts (without notches), being also heavy shearing equipment, due to the high power they require. These shearing equipment make the cut very slowly, always cutting only one side of the nut first, repositioning the machine to cut the opposite side. This means that the objective of reducing nut extraction times is not achieved, being equipment difficult to manipulate and position, so operators need to hang on some structure to operate.

Another relevant document for this application is that published as WO 2013/1 14241, in the name of the same applicant. This document discloses a shearing equipment of nuts that fit bolts, where said nut has a notch in at least two of its lateral faces, which are used in high tonnage machines, such as in mineral grinding mills , which has a hydraulic cylinder that drives a punch that allows to generate the displacement of the jaws with the knives, where said equipment allows to split or break said nuts, minimizing the time for maintenance of the mill for grinding minerals and increasing its availability. The shearing equipment also comprises a head consisting of a shoe die, which has a first left half and a second right half, which is semi-open, leaving a cavity to allow the alignment of the nut with the knives, located at the ends front of the upper and lower jaws, wherein said shoe socket is attached to a plurality of plates, which act as a spring, being located on each side of said shoe shoe, in which the plurality of plates allow the left and right halves they open when the blades enter with the jaws, leaving also clearance and space for the two pieces of the nut that have split.

The use of this equipment was effective to make the cutting of the nuts with notches, however, in its industrial execution, this turned out to be very heavy, with a weight of 38 Kilos that had to be operated by two workers, in addition to the high forces generated by the cylinders, and therefore, not acceptable for work in mining plants.

The documents described above disclose devices that break nuts, for different devices and that generally present problems or impediments to e! normal removal of a nut, such as when it is rusty or with a tightening that exceeds the possibility of being removed with a normal torque, and therefore, there is no alternative but to break it. The only document that discloses how to cut this type of nuts, is that published as WO 2013/1 14241, but its high weight and high tonnage of force that the cylinder piston should apply, make this equipment impracticable in mining plants. All the documents formerly commentator, they are documents that do not teach how to break nuts that operate on machines! high tonnage, such as mineral grinding mills, either autogenous or SAG, nor those that have nuts that have opposite notches on the outer faces.

In mineral grinding mills, the nuts are installed outside the mantle leaving a portion at the end end of the screw, cantilever, as shown in Figure 3.

Due to the foregoing, an objective of this invention is to provide a device that allows the screw to fit, which sometimes protrudes up to 3 inches (76.2 mm) above the nut. This is very relevant because when entering frontally with the shearing equipment there must be enough space for the end of the screw, otherwise it would not be possible to make the cut.

A second objective of the present invention is to provide a light equipment of between 5 to 10 kilos and with a low power, so that it can be operated by a single worker.

A third objective of the present invention is to minimize the concentration of efforts. The solution to this problem is vital for the useful life of the knives because having a bevel at the entrance of the notch of the nut achieves a greater contact surface between both elements, achieving a greater amount of cutting cycles of the knives and a better operation This allows the knives to penetrate and generate the concentration of stresses at the tip of the notch, so that it propagates towards the crack, allowing them to have greater support on the entrance walls of the notch.

A fourth objective is to provide a cutting equipment that is made up of two portions, a first portion that is arranged parallel to the mill drum, and a second portion, which is arranged angularly or inclined, in order to avoid that the equipment touches with an adjacent nut in the drum of the mill. This technical problem is very relevant to solve, because the parallel cut allows to perform the operation with greater comfort and the angular or inclined portion, allows the coupling of a hydraulic cylinder, which does not hinder the work of the operator. Other shear equipment of the prior art, have different positions that do not allow working comfortably, efficiently and safely. A fifth objective of the present invention is to provide a low weight shearing equipment, between 5 to 10 kilos, so that it is operable by a single worker and that is capable of generating sufficient force to split the nut with notches in its Exterior.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a greater understanding of the invention, constitute part of this description and further illustrate part of the prior art and some of the preferred embodiments, to explain the principles of this invention.

Figure 1 shows a perspective view of a nut with notches on its outer faces.

Figure 2 shows an elevation view in the cutting sequence, with two shearing blades that are used in the equipment of the present invention.

Figure 3 shows a schematic view of a mill mantle with a nut and the terminal part of a screw protruding from the outer mantle.

Figure 4 shows a perspective view of the shearing equipment of the present invention.

Figure 5 shows a side view of the shearing equipment of the present invention.

Figure 6 shows a plan view of the shearing equipment of the present invention.

Figure 7 shows a perspective view of the fixed knife of the present invention.

Figure 8 shows a perspective view of the movable knife of the present invention.

Figure 9 shows a perspective view of the shoe die of the shearing equipment of the present invention.

Figure 10 shows a left side view of the cylindrical body portion of the shearing equipment of the present invention.

Figure 1 1 shows a right side view of the cylindrical body portion of the shearing equipment of the present invention.

Figure 12 shows a perspective view of the shoe die of the shearing equipment of the present invention. Figure 13 shows a front view of the shoe die of the shearing equipment of the present invention.

Figure 14 shows a rear view of the shoe die of the shearing equipment of the present invention.

Figure 15 shows a side view of the hydraulic cylinder of the shearing equipment of the present invention.

Figure 16 shows a rear view of the hydraulic cylinder of the shearing equipment of the present invention.

Figure 17 shows a front view of the process of cutting a nut with the shearing equipment of the present invention.

DESCRIPTION OF THE INVENTION

The present invention relates to a shearing equipment (7) of nuts (1) having a notch (3) in at least two of its lateral faces (2), which are used in high tonnage machines, such as for example in mineral grinding mills. These mills have in their interior coatings and lifters that are changed periodically and that are fixed from the inside to their housing (5) by means of screws (6), and on the outside, said nut (1) is placed with notches (3 ). The objective of this invention is to complement the nut (1) with notches (3) by means of a shearing equipment (7) that allows splitting or breaking said nuts (1), minimizing the downtimes for maintenance of the mineral grinding mill .

The shearing equipment (7) is made up of a head (8) and a rear portion (9) that contains the hydraulic cylinder. The head (8) is formed by a hollow shoe socket (10) with a hexagonal outer contour and a hexagonal inner contour, which on a first inner face is provided with a groove shaped like a female dovetail (1 1) for accommodate a fixed blade (4b) that fits into the notches (3) of the nut (1). This fixed blade (4b) has a triangular cross-section, at whose half of its height, and on a first side, a first transverse projection of rectangular section (12) emerges, and at half of its height from a second side, a second cross-sectional projection of rectangular section (13) emerges, which divides the body into two halves, a sharp portion (15) and a posterior portion of lace (14) that is shaped like a female dovetail. In addition, said transverse projections (12, 13) serve as support for the face (2) of the nut (1) having a notch (3), where the latter fits into the sharp portion (15) of the fixed blade (4b).

The head (8) that is formed by a hollow shoe socket (10), which has a hexagonal outer contour and a hexagonal inner contour, has a second inner face facing said first inner face having said groove in the form of a tail of female dove (1 1), a recessed cylinder (20) that has in its front portion and into the hollow shoe die (10), a rectangular section groove (19) that houses a movable blade (4a). Because the blades (4a, 4b) located in the hollow shoe socket (10), must operate perpendicularly on both the casing wall (5) of the mineral grinding mill and the nuts (1), the recessed cylinder (20) is slightly inclined with respect to the hollow shoe socket (10), so that it is possible to connect the hydraulic cylinder that will operate the equipment, so that it is easier for the worker to operate the equipment.

For the reason explained above, the movable blade (4a) is formed by a body (17) in the form of a trapezoidal prism of similar width to the rectangular section groove (19), wherein said body (17) has lower and rear faces They are inclined. The lower face of the body (17) is inclined collinearly to the axis of symmetry of the recessed cylinder (20), and the rear face is inclined to be perpendicular to the piston of the hydraulic cylinder (21) that will move it. Said piston travels to the interior of the hollowed cylinder (20), since it has an internal cavity or through hole, of cylindrical shape. In the front portion of the body (17), a triangular section portion (16) emerges, whose sharp edge is the cutting portion of the blade (4a). On the back of the body (17), a sleeve of straight circular section (18) is located that is perpendicular to the rear face of said body (17), which is the means of splicing the piston moved by the hydraulic cylinder ( 21), which is coupled to the recessed cylinder (20).

The hollowed cylinder (20) has a thread or thread internally within its recess and in the rear portion that allows the coupling of a hydraulic cylinder (21). To this end, said hydraulic cylinder has in its front portion, a cylindrical projection (22) having a thread or thread to be screwed to the hollowed cylinder (20). Said hydraulic cylinder (21) has a connector (23) laterally, which receives the hose from the pump that provides the hydraulic fluid for the actuation of the piston. This piston (not shown) joins through the hollow cylindrical hollow of the recessed cylindrical (20), to the straight circular sleeve (18), so that the movable blade (4a), by action of said piston, can move inside the rectangular section groove (19), until the notch (3) of the nut (1) is reached.

The angle of the sharp triangular section portion (15) of the fixed blade (4b) is smaller than the angle of the acute triangular section portion (16) of the blade (4a).

This is because the fixed blade (4a) acts as a support for the nut (1) with notches (3) and the mobile blade (4b) acts as a cutting blade, which does not reach the bottom of the notch (3 ), if not contact the notch walls (3) to make an effort perpendicular to the walls, so that the opening of the notch walls (3) causes the notch tip (3) to cause the increase of the breaking stress, which reaches the thread of the nut (1), which prevents damage to the thread of the screw (6).

To facilitate the maneuvering of the shearing equipment (7) for a single worker, on the outer face (24) of the recessed shoehorn die (10), a folded plate (25) which supports a handle (26) is installed, by welding. ), for the worker support one of his hands. This folded plate (25) is installed on the outer face (24), which coincides with the inner face where the groove in the shape of a dovetail (1 1) that houses the fixed blade (4b) is located. Also, in the upper outer portion of the hydraulic cylinder (21), a handle (27) is adhered, which is collinear with the handle (26), whereby it is possible to obtain a safe operation of the shearing equipment (7). In the upper portion of the handle (27) there is an actuation button (28), which, when pressed, allows the passage of hydraulic fluid into the hydraulic cylinder (21). On the rear portion of the handle, the electric cable emerges that allows the shearing equipment (7) to be connected to the pump motor (not shown).

This shearing equipment (7) allows the cutting of the nut (1), more easily than the shearing equipment disclosed in WO 2013/1 14241, in the name of the same applicant, since it is no longer required that Two blades are moved simultaneously and coordinated. With this invention, a single blade is moved with which, the force required is much less, and therefore, this leads to the shearing equipment of the present invention, being of less weight, between 5 to 10 kilos, facilitating the operation by a single worker.

In figure 17, the working procedure of the blades (4a, 4b) is observed, to cut the nut (1) with notches (3), where now, one is mobile and the other is fixed.

Claims

one

one . - A shearing equipment (7) of nuts (1) that fit bolts (6), where said nut has a notch (3) in at least two of its lateral faces (2), which are used in machines high tonnage, such as in mineral mills, CHARACTERIZED because said shearing equipment comprises:

a hollow shoe socket (10) with a hexagonal outer contour and a hexagonal inner contour, which on a first inner face is provided with a groove in the form of a female dovetail (1 1) to accommodate a fixed blade (4b) that it fits into the notches (3) of the nut (1);

said hollow shoe die (10) has on a second inner face, located on the opposite side of said first inner face, an inclined hollow cylinder (20) with respect to the hollow shoe die (10), which it has in its front portion and towards the inside of the hollow shoe socket (10), a rectangular section groove (19) housing a movable blade (4a);

said inclined hollowed cylinder (20) has internally within its hollow and in the rear portion, a thread or thread that allows the coupling of a hydraulic cylinder (21), which has in its front portion, a cylindrical projection (22) having a thread or thread to be screwed to the inclined recessed cylinder (20); Y

said hydraulic cylinder (21) has a connector (23) laterally, which receives a hose from a pump that provides the hydraulic fluid for actuation of the piston; which is connected through the internal cylindrical cavity of the inclined recessed cylindrical (20), to the movable blade (4a) that moves inside the rectangular section groove (19), until reaching the notch (3) of the nut

(one )-

2. - A shearing equipment (7) of nuts (1), according to claim 1, CHARACTERIZED because said fixed blade (4b) has a triangular cross-section, at whose half its height, and on the first side, emerges a first transverse projection of rectangular section (12), and in the middle of its height of a second side, a second transverse projection of rectangular section (13) emerges, which divide the body of the fixed blade (4b) into two halves, one 2 acute portion (15) and a posterior portion of lace (14) that is shaped like a female dovetail.

3. - A shearing equipment (7) of nuts (1), according to claim 1 or 2, CHARACTERIZED in that said movable knife (4a) is formed by a body (17) in the form of a trapezoidal prism of width similar to the groove of rectangular section (19), wherein said body (17) has lower and rear faces that are inclined, where the lower face of the body (17) is inclined collinear to the axis of symmetry of the hollowed cylinder (20), and the face posterior, it is inclined to be perpendicular to the piston of the hydraulic cylinder (21) that will move it; where in the front portion of the body (17), a triangular section portion (16) emerges, the sharp edge of which is the cutting portion of the blade (4a) and at the rear of the body (17) a sleeve of straight circular section (18) that is perpendicular to the rear face of said body (17), which is the means of splicing the piston moved by the hydraulic cylinder (21), which is coupled to the recessed cylinder (20).

4. - A shearing equipment (7) of nuts (1), according to any of the preceding claims, CHARACTERIZED because the angle of the sharp triangular section portion (15) of the fixed blade (4b) is smaller than the angle of the sharp triangular section portion (16) of the blade (4a).

6. A shearing equipment (7) of nuts (1), according to any of the preceding claims, CHARACTERIZED because on the outer face (24) of the recessed shoehorn die (10), a bent plate (25) is installed to which a handle (26) is adhered, wherein said folded plate (25) is adhered to the outer face (24), which coincides with the inner face where the groove in the shape of a dovetail (1 1) that houses the blade is located fixed (4b).

7. A shearing equipment (7) of nuts (1), according to any of the preceding claims, CHARACTERIZED because in the upper outer portion of the hydraulic cylinder (21), a handle (27) is adhered which is collinear with the handle ( 26).

8. A shearing equipment (7) of nuts (1), according to claim 7,

CHARACTERIZED because said handle (27) has an actuation button (28) in the upper portion and an electrical cable emerges from the rear portion.