RU2299969C2 - Executive mechanism acting with constant force - Google Patents

Abstract

FIELD: mechanisms adapted to utilize unidirectional force for lifting and retaining load in direction transversal to force application direction, namely for centrators, caliper apparatuses, engaging devices, pulling and lifting devices.

SUBSTANCE: mechanism comprises couple of force transmitting units, which may perform relative linear movement, and lever mechanism taking the force. Lever mechanism is provided with member movable in direction transversal to force transmitting units sliding direction. Lever mechanism has guiding means to convert linear movement of force transmitting units into lever mechanism projection or retraction. Guiding means is formed as wedge made as a single unit with lever mechanism arm. Guiding surface of the wedge cooperates with wheel, which is part of force transmitting unit.

EFFECT: extended field of application and widened range of radial expansion.

5 cl, 19 dwg

Description

The scope of the invention

The present invention relates to mechanisms that apply a force applied in one direction to lift or hold a load in a direction perpendicular to the direction of the applied force. Such mechanisms are used in many fields and can be used, for example, in tools designed to work in wells or pipes, such as centralizers, calipers, gearing devices, and traction devices. The invention, in particular, can be applied in the field of traction devices intended for the delivery of logging and service tools in deviated or horizontal oil or gas wells, or in pipelines in which such tools cannot be easily moved by gravity. The invention can also be applied in lifting devices.

Description of related technical solutions

After an oil or gas well has been drilled, it is often necessary to log the well using various measuring tools. This is usually accomplished through logging tools with wires lowered into the well on a wireline. It may also be necessary to inspect the pipelines and, therefore, move various measuring instruments along the pipe.

Some logging tools can only function properly if they are located in the center of a well or pipe. This is usually provided through a centralizer. All centralizers operate on the same general principle. A large number of arcuate springs or lever mechanisms of various types spaced apart from each other at an equal distance extends radially from the central shoe to the wall of the borehole or pipe. These springs or lever mechanisms come into contact with the wall of the borehole or pipe and exert a radial force on it, which tends to move the tool body away from the wall. Since the arcuate springs and linkages are usually symmetrical with respect to the central shoe, they tend to position the tool in the center of the well. Therefore, the radial forces exerted by these devices are often called centralizing forces.

Typically, centralizers remain open throughout their work. In other words, their linkage mechanisms are always biased toward the wall of the borehole, and they always remain in contact with this wall. Most centralizers are designed to operate in a wide range of borehole sizes. When centralizers expand or contract radially to accommodate changes in borehole size, their centralization forces may vary. In wells that run almost vertically, changing the radial force is not a problem, since the radial component of the tool weight is small and even weak centralizers can handle it. In addition, the centralization force and the friction resistance to which it leads represent such a small part of the total tension of the wireline that their change may be insignificant for all practical purposes.

However, wells that have horizontal or significantly inclined sections are a problem. In the horizontal section of the well, the centralizer must be strong enough to lift the full weight of the tool from the wall of the borehole. On the one hand, the minimum level of centralization force should be equal to the weight of the tool to ensure proper operation with all sizes of the borehole. On the other hand, with a different size of the borehole, the force exerted by the centralizer may be excessive, causing excessive frictional resistance, which slows down the movement of tools along the borehole. This situation led to the development of centralizers operating with constant force, which were previously disclosed and supplied by industry. However, the present invention proposed a new approach to the creation of such centralizers, acting with constant force.

Like centralizers, calipers extend shoulders or linkages from the tool body to the wall of the borehole. One of the differences between centralizers and calipers is that the shoulders of the caliper can be individually actuated and may not open the same amount. Another difference is that the caliper arms usually selectively open and close to the tool body by some mechanical means. Thus, the shoulders of the caliper do not necessarily remain in contact with the wall of the borehole for the entire time. Various measuring instruments are often mounted on the shoulders of the caliper. In order to ensure proper operation of some of these measuring instruments, it is often necessary to maintain a predetermined range of radial forces with which the caliper arms are pressed against the borehole wall. This requirement is sometimes difficult to fulfill in horizontal sections of the well and with variable well sizes. The reason is that, like centralizers, the gain in the strength of the lever mechanisms of the caliper varies with the size of the borehole. Thus, the mechanical devices responsible for opening and closing the caliper should provide a variable output force. This usually leads to low efficiency of the mechanical device and to its insufficient use in a wide range of borehole sizes. Therefore, it is useful to develop lever caliper mechanisms that allow practically constant radial forces to be applied in the presence of constant mechanical input power from the drive device. The present invention has created such a mechanism.

For horizontal and significantly deviated wells, another problem is characteristic. Logging tools cannot be effectively moved in such wells by gravity. This led to the need to develop alternative ways of moving. One such method is based on the use of a pulling device in a downhole that pulls or pushes logging tools along the wall.

In downhole traction devices, such as those described in US Pat. Nos. 5,954,131 and 6,179,055 B1, various radially expanding mechanisms are used to force wheels or gears to engage the borehole wall. Regardless of the principle by which the movement relative to the wall of the borehole is provided, the traction force that the traction device can create is directly proportional to the radial force exerted by the mechanism. Like centralizers and caliper, traction devices for downhole wells are designed to operate over a wide range of borehole sizes. As with centralizers, they are also characterized by the problem of changing radial forces as a function of the size of the borehole. Typically, for a given expansion mechanism, traction is weakened depending on the size of the borehole. Preferably, the radial force developed by the traction device is constant. However, a satisfactory solution to this problem has not yet been proposed.

Some traction devices use several groups of linkages of different sizes to provide a relatively constant traction in a wide range of borehole sizes, however, these mechanisms must be replaced on the surface, which is very inconvenient. In addition, some wells are drilled so that they will have a variety of sizes, so more than one mechanism will have to be manipulated. According to the present invention, a mechanism has been created that can be used with all known traction concepts to provide a constant radial force and, consequently, an appropriate traction in a very wide range of borehole sizes.

To perform their functions, centralizers, calipers and traction devices are based on mechanisms that expand in the radial direction. These mechanisms can be active or passive. Active mechanisms are supplied with energy by means of hydraulic or electric drive devices. They perform normally closed and only operate during operation. Passive mechanisms are usually based on springs designed to create a radial force acting in the outward direction. While passive mechanisms developing continuous effort are supplied by industry, active mechanisms operating with constant force have not been proposed.

In the present invention, both a passive and an active mechanism can be used, which can create a substantially constant radial force.

In a known technical solution related to the principle of operation of the invention, either the design of centralizers developing constant force or the use of wedges in centralizing devices are disclosed. For example, US Pat. No. 4,615,386 discloses a centralizer that produces approximately constant radial force over a range of borehole sizes. The constancy of force is ensured by a combination of two springs having different characteristics. The sum of the forces of the two springs remains approximately constant over a wide range of movements of the centralizer arms. The advantage of this approach is its simplicity. The disadvantage of this approach is that it can only be used in centralizers, but not in calipers and gearing devices, in which case selective opening and closing of the shoulders is required. Another disadvantage is that with this principle of operation it is necessary that the centralizer be quite long, and this in some cases may be undesirable. Similarly, US Pat. Nos. 4,557,327 and 4,803,005 disclose centralizing devices that provide a substantially constant centralization force by combining at least two different types of springs. The advantages and disadvantages of these devices are similar to the advantages and disadvantages discussed above. US Pat. No. 5,005,642 discloses a centralizer of a logging tool that provides a reduced degree of change in centralization force by moving the attachment points of the centralizing arms on opposite sides of the tool body. Moreover, the angle between the centralizer arm and the tool body will never be able to take a zero value, which is a condition that makes most other centralizing devices based on actuating in the axial direction inoperative. The disadvantage of this approach is that it does not completely solve the problem, since the radial force still varies depending on the size of the borehole. This also makes the design of the device difficult, especially in the case when it is desirable to use more than two centralizing shoulders.

In all the patents discussed above, radial expansion of the centralizer is achieved through a mechanism that consists of two arms connected to each other by one of their ends and fastened by their other ends to the movable shoes. When the distance between the shoes changes, the attachment point of the two shoulders moves inward or outward in the radial direction. Another approach for producing a radially expandable device is based on the use of tapering surfaces or wedges. Centralizers based on this principle are disclosed in US Pat. Nos. 5,348,091 and 5,934,378. Radial expandable drilling tools are disclosed in US Pat. No. 4,693,328. The radial expansion principle is again based on moving parts that slide along inclined surfaces (wedges) ) The advantage of this concept is that the forces created can be significant. The main disadvantage is the relatively limited range of radial expansion.

The present invention eliminated the disadvantages of both types of mechanisms that are expandable in the radial direction, which are discussed above, by kinematically combining these mechanisms in one device, which allows to obtain other results containing signs of novelty that are different from the signs of any of the mentioned devices.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, an actuator with constant force is provided that can be used with all known concepts of producing traction in a borehole to provide a substantially constant radial force and therefore corresponding traction in a wide range of borehole sizes.

According to another aspect of the invention, there is provided an actuator acting with constant force, which can be used as a passive or active mechanism capable of creating a substantially constant radial force for its application to opposing surfaces.

According to another aspect of the present invention, there is provided an actuator operating with constant force, which can be effectively used as an operational component of a centralizer, an engaging device, a lifting device, or other devices for transmitting force, and can be actuated by springs, hydraulic motors, pneumatic motors, devices for mechanical actuation, and the like.

In short, the present invention is a mechanism in which a force applied in a first linear direction is used to lift or hold a load, or to transmit force in a second linear direction that is substantially perpendicular to the first linear direction. The devices and mechanisms created according to the principles of the present invention are designed so that the force required to hold the load is practically constant and independent of the load position in the second linear direction. In particular, the invention relates to logging tools or other devices for wells that move along the inner surfaces of a borehole or pipe, or between spaced apart surfaces. The invention can usually take the form of a centralizer, caliper, gearing device, or a traction mechanism for use in wells, or it can take the form of a lifting device or a load holding device when it is implemented as jacks or other devices for lifting or holding the load. The function of the present invention is the application of radial forces to the inner cylindrical wall of a borehole, or a round channel, such as a pipe, or in acting on them, to centralize objects inside a borehole or pipe in order to fulfill the function of engagement or create mechanical resistance, allowing for efficient operation internal traction devices for moving objects such as logging tools. When used as a centralizer for logging tools, a large number of radially movable drive linkages with which the present invention is made holds the logging tools in the center of the borehole and thereby improves the accuracy of the logging process. When the invention is used as a caliper, it extends the shoulders or other link mechanisms to the wall of the borehole and a controlled radial force affects the surface of the wall. When the invention is used as an engaging device, the application of radial forces that create sufficient friction to the wall of the borehole or pipe or their impact on this wall can occur to prevent any slipping at the contact points between the engaging device, and a wall surface of a borehole or pipe. The latter is necessary for the design and operation of downstream wells of such traction tools, which are often used to move other tools along wells that have horizontal sections or sections with a significant slope. The main advantage of the present invention is that the magnitude of the radial forces that it exerts on the wall of the borehole will in fact be constant and independent of the size of the borehole.

The main elements of the invention are parts for transmitting force or shoes, wheels, axles and at least one pair of link arms with integrated wedges or with guide surfaces having a predetermined geometry defined by link arms. For the purposes of the present invention, it is assumed that each of the terms “force transmitting parts” or “shoes” defines parts of any desired configuration that are relatively linearly movable, while one of the parts is movable or both parts are movable and, if desired, one of the parts is stationary . The link arms, power transmission parts, or the shoes and wheels are axially connected to form a linkage mechanism that can expand or converge in the radial direction when the distance between the shoes changes in the axial direction. The lever shoulders are connected to each other by means of a hinge element or an axis at one of their ends, due to which only the angular movement of the lever shoulders is possible. With their second ends, the lever shoulders are attached to individual shoes by means of axes or hinges, which can both rotate and slide inside an elongated slot made in the shoe body. Wheels or rollers that determine the movement of the control elements are rotatably attached to the shoes, and when they are in contact with the guide surfaces of the lever arms, they roll along the guide surfaces of the wedges intended for the transmission of force or along the guide surfaces that are built into the lever arms, formed on link arms or attached to link arms. Although wheels or rollers are shown as shoe elements serving to transmit power or parts serving to transmit power, structures other than wheels or rollers can be used within the scope and spirit of the present invention to transmit power from the shoes to guide surfaces wedges or leverage. The guiding surfaces for transmitting the force have a predetermined geometry so as to interact with the surfaces of the wheels or rollers used to transmit the force and create vectors of the resulting forces on the link arms, which are angled with respect to the linear direction of movement of one or both shoes. Such angled force vectors cause a pivotal movement of the link arms even when the link mechanisms are fully retracted. This distinguishing feature allows easy initial movement of the linkage mechanisms from their allotted positions.

The invention combines two separate principles, which allows for the required expansion in the radial direction. At small angles between the shoulders and shoes, radial force is created by means of wheels that roll along the surfaces of the wedges or lever shoulders that serve to transfer force. At large angles, the expansion movement of the linkage mechanisms is based on the principle of a triangular three-link linkage. The transition from one principle to another occurs when the intermediate angle of the lever arms is selected between the positions of the full lead and full extension. By combining these two principles and by selecting, arranging, and shaping the force transmitting forces of the guide surfaces of the wedge elements, a virtually constant input force can be provided, which is the main advantage of the present invention and distinguishes it from other similar devices.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more clearly understood when considering the following description with reference to the accompanying drawings, in which:

On figa-1F presents views of the first cited as an example of an embodiment of the design of the actuator according to the invention, acting with constant force, while they show the various positions of the said actuator from the closed or retracted position shown in figure 1A, to fully open or extended position shown in figure 1F;

figure 2 presents a diagram of the dependence of the force on displacement, illustrating the axial force required to hold the radial load, while the figure shows a small angular movement of the linkage mechanism by the wedge of the actuator and a larger angular movement of the linkage after the linkage is separated from the transmission wedge surface forces;

figure 3 presents a cross-sectional view of an embodiment of the design of the centralizer with bias springs, made according to the present invention, which can be used in wells or in other applications for the purpose of centralization, while it includes symmetrical opposite linkage mechanisms with a roller engaged with wedges on all lever shoulders;

figure 4 presents a cross-sectional view of an embodiment of the design of the centralizer with bias springs, made according to the present invention, while it has asymmetric linkage mechanisms containing a wheel or roller that engage with wedges only in the upper portions of the lever arm;

figure 5 presents a view in section of an embodiment of the design of the centralizer with bias springs having oppositely located asymmetric linkage mechanisms;

FIG. 6 is an isometric view showing an embodiment of a structure according to the present invention as a clamp of a down hole traction tool;

on figa presents a view in section of the upper part of the clamp traction tool for a downhole, which implemented the principles of the present invention;

FIG. 7B is a sectional view of the intermediate portion of the clamp according to FIG. 7A;

on figs presents a view in section of the lower part of the clamp according to figures 7A and 7B;

on Fig presents a cross-sectional view of the traction mechanism for the downhole, in which the principles of the present invention are implemented and which includes power traction wheels for providing engagement with opposite surfaces or opposite sides of the borehole;

FIG. 9 is a cross-sectional view of a traction mechanism for a downhole constructed in accordance with the present invention and including power circuits to enable engagement with opposite surfaces or opposite sides of the borehole;

10 is a cross-sectional view of a traction mechanism for a borehole constructed in accordance with the present invention and having rollers and rotary shoes for engaging gears with opposite surfaces or opposite sides of the borehole;

11 is a sectional view showing a lifting mechanism for raising and lowering an object in which the principles of the present invention are implemented and in which manual actuation of the opposed link mechanisms is provided by means of a rotary jack screw;

12 is a partial cross-section and a partial elevation view illustrating a scissor mechanism for lifting a load, having a group of scissor arms forming interacting link mechanisms with wedges and force-transmitting rollers for actuating the scissors with substantially constant force.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the invention are described below by way of example only. It is clear that in the development of any such real design option, a number of implementations must be provided - certain solutions in order to achieve the specific goals set by the developer, for example, coordination with the restrictions imposed on the system and business activity, which will vary from one implementation to another. In addition, it is obvious that such an attempt to develop can be difficult and time-consuming, but nevertheless it will be the usual work of qualified specialists in this field who have benefited from what is disclosed here.

Turning now to FIGS. 1A-1F, the basic principles of the present invention are presented therein by way of illustrations illustrating the operation, while the linkage mechanism of the device, acting essentially constant force, is shown in its closed or allotted state in FIG. 1A and at various stages of moving to the fully open or fully extended position shown in Figure 1F. The basic elements and principle of operation of the invention are schematically represented in FIGS. 1A-1F. Two arms 2 of the link mechanism with wedges 4, which are integral with the arms of the link mechanism, are connected to each other at their first ends by means of an axis or hinge 6. Axis 6 can also connect other elements to the arms of the link mechanism depending on the desired function of the designed device . For illustrative purposes, FIGS. 1A-1F show a wheel or roller 8 also mounted on an axle 6, it being understood that in this case the invention can be used as a centralizer with wheels 8 designed to contact opposite surfaces or to contact opposite the walls of the borehole. The second ends of the shoulders 2 of the lever mechanism are attached to the shoes 10 by means of pivoting fingers 12 that slide and rotate inside the elongated slots 14 made in the shoes 10. The wheels 16 are mounted together with the axles 18 on the brackets 20, which are parts of the shoes 10. The function of the wheels 16 is in rolling along the guiding surfaces 22 of the wedges 4 and interacting with the guiding surfaces 22 to transmit vector forces to the arms 2 of the linkage mechanism and to ensure the movement of the arms of the linkage arms. The movement of the shoes 10 is limited only by linear movement with respect to each other by means of other elements or devices serving to transmit power (not shown in FIGS. 1A-1F). All of these elements of the invention are combined to form a linkage, indicated at 25.

1A-1F show the position of the linkage 25 at various degrees of expansion in the radial direction. In FIG. 1A, the link mechanism 25 is shown in its closed or fully retracted position when the angle between the shoulders and the shoes is zero (in FIG. 1B-1F, the angle is designated by α). It should be noted that in this position, the wheels 16 that come into contact with the wedge surfaces 22 are located near their upper ends. It should also be noted that the pivot pins 12 are located at the front ends of the corresponding elongated slots 14.

Now imagine that the shoes 10 are offset towards each other by the axial forces indicated in Figures 1A-1F by the symbol F _a . This leads to the fact that the wheels 16 will roll down along the guide surfaces 22 of the wedges 4, thereby developing a force whose vector is oriented for pushing the arms of the lever mechanism upward and rotating them around the articulated fingers 12. During the movement of the lever mechanism, the shoulders 2 slide and turn at their second ends, which leads to the configuration shown in figure 1B. It should be noted that the angle α between the shoulders 2 and the straight line connecting the shoes 10 increases from a zero value in Figure 1A to a certain positive value in Figure 1B. In this case, the fingers 12 will be in the elongated slots 14 in some intermediate position. The pivot pins 12 move freely in the axial direction and therefore cannot hold any axial load. However, they prevent the second ends of the shoulders 2 of the linkage mechanism from moving in the radial direction. All these interactions force the first ends of the arms 2 of the linkage and the wheel 8 to move outward in the radial direction to extend the linkage 25 in the radial direction. When the wheel 8 comes into contact with the wall of the borehole, it begins to exert a radial force on it, moving the shoes 10 from the wall to the center of the borehole, thereby creating a centralizing effect.

Further expansion of the lever mechanism 25 in the radial direction based on the rolling of the wheels 16 along the guide surfaces 22 is shown in figures 1C and 1D. In these figures it is seen that the angle α continues to increase and the wheel 8 continues to move outward in the radial direction. In figures 1A-1D presents the first kinematic principle used in the invention, which is based on the interaction between the guide surfaces 22 of the wedges 4 and the wheels or rollers 16, which serve to transmit force. It should be noted that in FIG. 1D, the wheels 16 reached the lowest end of the wedge surfaces 22. This situation indicates that the radial expansion value based on this first kinematic principle has already been exhausted. It should also be noted that the articulated fingers 12 have reached the rear ends of the elongated slots 14. This position of the fingers 12 and wheels 16 represents a transition point between the two kinematic principles used in the invention. For this reason, the shoulder angle of the linkage mechanism in Figure 1D is indicated by α _t (transition). At angles smaller than α _t , the extension of the linkage mechanism in the radial direction will be achieved by means of wedges, while at angles greater than α _t , the extension of the linkage mechanism in the radial direction will be provided by means of the equivalent of a three-rod mechanism. The second kinematic principle on which the invention is based is presented in Figures 1D-1F. Two shoulders 2 of the lever mechanism and shoes 10 form a triangular three-rod mechanism with shoes 10, which are a rod of variable length. When the distance between the shoes 10 decreases, the triangle changes shape with the further movement of its top outward in the radial direction. It should be noted that the wedges 4 do not take any part in this movement, because, as shown in figures 1E and 1F, the guide surfaces 22 of the wedges 4 are allotted from the wheels or rollers 16.

Now imagine that the downward radial force F _r acts throughout the expansion process. We also imagine that the magnitude of the axial force F _a , which is necessary to overcome F _r and continue the expansion, will be recorded and presented in graphical form. Such a graphic image is shown in figure 2. The exact values of the magnitudes and shape of the curves shown in figure 2 will vary depending on the location of the wedge 4 on the shoulders 2 of the lever mechanism and on the radius of curvature of the guide surfaces 22 of the wedge. However, FIG. 2 sufficiently illustrates the advantage of combining two separate kinematic principles in one mechanism. In figure 2, the curve indicated by the symbol F _a (without wedge) illustrates the amount of axial force F _a that will be required to overcome F _r if only the second kinematic principle of the three-arm linkage is used. As follows from the graph according to figure 2, in this case, F _a rises sharply with small values of α. This means that the three-rod linkage mechanism on which many existing devices are based has real difficulties in maintaining radial loads at small angles. In fact, with α equal to zero, the axial force required to hold the load must be infinitely large, which means that a device for practical use cannot be designed to work in this range. The second curve in the graph according to figure 2 represents the possible values of F _a if two kinematic principles are combined, which is proposed in the present invention. You can see that it is possible to avoid a sharp increase in F _a at small angles, and that F _a remains fairly constant within a significant range of angle α. It should be noted that in figure 2 in no way exhausted the possible values of F _a that can be achieved by the present invention. It was previously indicated that by changing the location of the wedge 4 on the shoulder 2 and by changing the radius of curvature 4 and the geometry of the guide surface 22, almost any form of curvature can be provided depending on the function that is required from a particular embodiment of the invention.

Various embodiments of the invention are discussed in more detail in figures 3-12. The figure 3 presents one of the embodiments of the invention, made in the form of a centralizer tool. A minimum of three linkage mechanisms 25 (only two opposite linkage mechanisms are shown in FIG. 3) are combined with each other by means of common shoes 10. The shoes 10 slide along the guide portion 24. The shoe stopper 26 is made integrally with the guide portion 24, which restricts the linear movement of the shoes 10 along the guide portion 24. The guide portion 24 is also connected to the upper head 28 and to the lower head 30, which are used to connect the centralizer to other tools and devices in the column tools (details of connections with other tools are not essential for the present invention and are not shown in FIG. 3). The guide portion 24 may also include wires 32 passing through it for electrical communication with other tools in the tool string. The axial force that forces the centralizer to expand in the radial direction and place other tools in the tool string in the center of the borehole is provided by springs 34. As can be seen from the embodiment shown in figure 3, in order to construct a centralizer with a relatively constant centralization force, only one type of spring is needed.

The linkage 25 used to construct the various devices need not be symmetrical. Two devices that are designed with asymmetric linkage mechanisms, the operation of which is based on the principles disclosed above, are shown in figures 4 and 5. According to these figures, only one of the arms that are used to create the linkage mechanism has a wedge. Alternatively, wedges with guide surfaces having different geometries may be provided on shoulders that have unequal lengths.

In all of the embodiments discussed above, centralizers for a tool string are provided. Centralizers that provide continuous effort can be created using tools other than those discussed above. The present invention provides a new method by which such centralizers can be constructed.

However, the advantages of the invention are significantly higher in the case of devices that have the ability to selectively open their link mechanisms from the tool body and close these mechanisms in the tool body. The reason is that such “active” devices usually only have axial linear actuators designed to open and close the linkages in the tool, which is the opposite of the elements used in centralizers that have a radial force component. Examples of devices that require selective opening and closing of lever mechanisms are calipers and traction tools for downhole wells. An embodiment of the invention used as a clamp in a traction device for a downhole is shown in FIGS. 6 and 7A-7C. The figure 6 presents a view in three dimensions of the clamp traction tool, which is designed using the principles of the actuator discussed above, acting with constant force. The traction tool clamp has two main functions. The first function is to perform selective opening and closing of various mechanisms and to centralize the tool in the borehole when such a need arises. In this regard, the clamp of the traction device is not much different from the centralizers shown in figures 3-5. The difference is that the clamp is not opened continuously and is driven by hydraulic or electromechanical actuators that provide selective opening or closing. The second function of clamping the traction device is to selectively engage the tool with the borehole wall. In the embodiment shown in FIG. 6, this is achieved by installing cams 42 at the vertices of the link mechanisms 25 and a device for selectively fixing the geometry of the link mechanism (not shown in FIG. 6). The principle that the cams 42 selectively engage the tool with the borehole wall, as well as the physics of traction, are disclosed in U.S. Patents 5,954,131 and 6,179,055, as well as in U.S. Patent Application 09/921825, incorporated herein by reference. Since they are not important for the operation of the proposed invention, their detailed discussion is not given here.

As shown in figure 6, the clamp of the traction device consists of three symmetrical link mechanisms 25. Like the description regarding figure 1, each link mechanism consists of two arms 2, which are connected to each other at their first ends via axis 6. Axis 6 also connects other clamping elements, for example wheels 8 and a bi-directional cam 42, which is responsible for carrying out the pulling action. According to figure 6, the three upper arms 2 are attached to the shoe 10, which can slide in relation to the body 44 of the clip. This is also similar to the description given in relation to figure 1. However, the three lower arms 2 are not attached to the movable shoe, but instead are attached to the fixed shoe 40, which is a part of the clamp body 44, made together with it as a whole. This demonstrates the flexibility of the invention. As explained previously, the only requirement for the operation of the invention is that the shoes 10 can move axially with respect to each other. However, there is no need for both shoes to move relative to the tool body. Figure 6 also shows other elements of the invention, such as wedges 4, guide surfaces 22 of the wedges, wheels 16, pivot pins 12, and slots 14. It should be noted that the clip according to figure 6 is shown in its fully open or extended state. The movable shoe 10 and the stationary shoe 40 are in contact, which can be seen in the immediate vicinity of the wheel 16. It should also be noted that the fingers 12 are located at the lower end of the slots 14, which indicates that the second kinematic principle of the invention is involved. Figure 6 also shows that the guiding surfaces 22 of the wedges can be made flat (infinite radius of curvature) to provide the desired force-related characteristics.

The basic elements of the invention shown in FIG. 6 can be combined with other link mechanisms to construct more complex mechanisms. Although the invention has been described with reference only to a basic group of elements, it will be apparent to those skilled in the art who have benefited from the above description that other embodiments may be devised that do not fall within the scope of the invention disclosed herein.

Figures 7A-7C are cross-sectional views of an embodiment of a clamp of a downhole traction device shown in Figure 6. Figure 7B is a continuation of Figure 7A, and Figure 7C is a continuation of Figure 7B. The lever mechanisms 25 for clamping the traction device shown in figures 7A-7C are presented in their fully open position. It should be noted that the wheels 16 are located at a distance from the guide surfaces 22 of the wedges. In addition to the structural elements of the design discussed previously, FIG. 7B shows an actuator 60 that provides the axial force required to selectively open the lever mechanism 25 from the tool body and close it in it, and also shows the details of the hydraulic control circuits required for the clamp to operate. In this particular embodiment, the axial force is generated by a hydraulic actuator 60, which consists of a piston 62, a spring 64 and dynamic seals 66 and 68. The piston 62 of the actuator 60 can move up and down when the chamber 70 is connected to a source of working fluid under high pressure (not shown in figures 7A-7C) and disconnect it from this source. The piston 62 is attached to the movable shoe 10 by a screw 72 and the movement of the actuator causes the shoe 10 to move relative to the shoe 40. Other elements of the design shown in Figures 7A-7C are a high pressure accumulator, generally indicated at 80, and two hydraulic sleeves 85 and 90, which control the opening and closing of the lever mechanisms 25, and also control the process of creating traction. Since the high-pressure accumulator 80 and hydraulic sleeves 85 and 90 are not directly related to the operation of the invention, and since they are disclosed in US Patent Application 09/921825, which is simultaneously filed, they are not discussed in detail here. All other elements of the invention shown in figures 7A-7C have the same designations and perform the same functions as the elements discussed in relation to the previous figures.

It will be apparent to those skilled in the art that traction mechanisms other than those with cams can be combined with the invention. Thus, the invention can improve the operation of virtually every traction tool for a downhole, regardless of the principle on which the creation of traction force of the traction device is based. Examples of the use of various traction devices in conjunction with the invention are shown schematically in figures 8, 9 and 10.

Figure 8 shows a traction tool for a downhole in which traction is generated by power drive wheels 100 mounted on the tops of the link mechanisms 25. Like the design of the asymmetrical link mechanism shown in Figure 4, the traction tool shown in Figure 8 has shoulders 2 equipped with wedges 4 only on the lower side of each link mechanism 25. The two upper arms 102 can only rotate with respect to the fixed shoe 104, which is part of the tool body 106, complete together with him as one. The shoulders 102 also accommodate drive chains (not shown) that transmit rotational motion from an engine (not shown) inside the tool body 106 to the drive wheels 100. The movable shoe 10, shoulders 2, wedges 4, wheels 16, fingers 12 and slots 14 function as follows as described in relation to Figure 1. Figure 8 also schematically shows one type of actuator 110 that can be used to selectively open and close the lever mechanism 25. In this embodiment, the actuator 110 c worth of motor 112, which drives a screw 114. When the screw 114 is turned, ball nut 116 moves upward or downward. The ball nut 116 transmits its linear movement to the shoe 10 by means of a spring 118, which gives flexibility to the linkage 25, which is necessary when the traction tool encounters changes in the size of the borehole or other obstacles.

Figure 9 schematically shows another traction mechanism that can be used in conjunction with the invention. In this case, the chains 120 are mounted on the edges of the symmetrical link mechanisms 25. The chains are attached to the link mechanisms 25 by pivoting fingers 6, which can slide and rotate in the slots 124 made in the chains 120. At the upper ends of the chain 120 are attached to the shoulders 130, which are similar the shoulders 102 in FIG. 8 contain mechanical elements (not shown) for transmitting rotational motion from an engine (not shown) in the tool body 44 to the drive sprockets 122 of the chains 120. At their lower ends, the chains 120 are attached to another group of shoulders 132, which provide the traction tool through the change in the size of the borehole and other obstacles. The shoulders 132 are attached to the tool body 44 by means of fingers 134 that slide in the slots 136. Figure 9 also shows a movable shoe 10 and a fixed shoe 40 that perform exactly the same functions as the functions described in relation to figure 6. Actuator 140 , shown in figure 9, operates on the basis of a principle different from the principle of operation of the actuator 110 shown in figure 8. The actuator 140 contains a hydraulic piston 142, which is a single part with a movable shoe m 10. This demonstrates the flexibility of the invention and that the invention will work with a variety of actuators that operate on different principles. The type of actuator used does not affect how the extension is provided in the invention.

Figure 10 is a schematic view of yet another embodiment of the present invention in the form of a downhole traction system. In this case, the roller assemblies 151, which consist of rollers 152, are mounted on inclined axles 154 at the vertices of the link mechanisms 25. Traction is provided by rotating the movable shoe 10 and the stationary shoe 160 with respect to the central guide part 164 of the tool body 44. The direction of rotation is indicated in figure 10 by arrow 162. When the entire group of linkages 25 rotates, the traction tool moves in a spiral along the inner wall of the borehole. The rotational movement of the traction mechanism is created by an engine and a gear (not shown), which are located inside the tool body 44. Next, the rotational movement is transmitted to the shoe 160. It should be noted that the shoe 160 can only freely rotate with respect to the central guide part 164, and its sliding with respect to the tool body 44 is prevented by the protrusion 166, which is formed by an enlarged portion of the central guide part 164. Another shoe 10 can perform both rotation and translational movement with respect to the central guide part 164, as indicated by arrows 172 and 168. When the shoe 10 slides up or down on the central of the steering part 164, the link mechanisms 25 will expand or retract radially. Similar to the previously discussed construction options, the progressive movement of the shoe 10 up or down is provided by a linear actuator, indicated by 170. In figure 10, the actuator is shown in the form of a hydraulic piston 174, which is a part made integral with the shoe 10. As explained previously, without deviating from the scope of patent claims and the essence of the present invention can also be designed actuators operating in accordance obstacle to other principles.

In all discussed design embodiments, the invention has been combined with other mechanisms to construct various tools that are designed to work in both wells and pipelines. However, the invention is not limited to these embodiments. In general, the invention can improve the operation of any device that is designed to hold a load in one direction by applying a force in a second direction perpendicular to the first direction. Two such design options are presented in figures 11 and 12. Figure 11 shows a design variant according to the present invention, which functions as a lifting device, such as a jack, designed to raise and lower a self-propelled vehicle. According to figure 11, one symmetrical link mechanism 25 is attached to the base 180, while another link mechanism 25 is attached to the lifting device 182. Two elements for transmitting force, or shoes 10 and 190 function in exactly the same way as described in relation to figure 1, when they move in relation to each other in the axial direction. The axial actuator in this case is a mechanism consisting of a screw and a nut, while the driven nut 184 is part of the shoe 10. The screw 186 is threaded into the nut 184 and can rotate with respect to the shoe 190 by means of a crank handle 192 The linear movement of the propeller 186 with respect to the shoe 190 will be prevented by the stopper 188 of the support assembly 194. Most existing car jacks using triangular kinematic mechanisms are characterized by that the beginning of work they are very difficult when they are fully compressed. In the present invention, this problem is solved. As explained with reference to figures 1 and 2, the axial force required in the invention is virtually constant. Thus, the rotation force, which must be applied to the crank handle 192 in order to lift the load, will also be constant and therefore the jack can easily begin to work from a compressed position.

Another embodiment of the invention, which can be used to lift the load in one direction by applying a force in the perpendicular direction, is shown in figure 12. According to figure 12, the actuator 200, which creates the force F _a , is used to lift the load 202, which acts in the lower direction with force F _r . As can be seen in this figure, the shoulder 2 can be extended beyond the location of the hinge or axis 6, which connects the two shoulders 2 of the lever mechanism in the hinge assembly. This does not change the principle according to which the invention operates, and again demonstrates the flexibility of the invention. Adding additional lever mechanisms 204 connected at the locations of the fingers 206 and 208 does not change the principle of operation of the invention. Qualified specialists in this industry will easily understand that within the scope of the invention, a wide variety of mechanisms and devices designed for various industrial applications can be designed.

Although it is permissible to carry out various modifications and alternative forms of the invention, specific examples of its implementation are shown here in the figures and are described in detail. However, it should be borne in mind that the description of specific design options provided herein is not intended to limit the invention to the particular forms disclosed, rather, it is intended that the invention covers all modifications, equivalents, and alternative options that are within the scope of the patent claims of the invention as defined by the appended claims .

Claims (5)

1. The method of applying to the object, essentially constant force, according to which the actuator is located close to the object, acting with constant force, while the actuator, acting with constant force, contains a pair of parts for transmitting force, located with the possibility of making a relative linear movement, and at least one of the parts for transmitting the force is placed with the possibility of linear movement, and the linkage mechanism associated with the parts for transmitting the force to perceive the force and comprising a first force transmission member movable by a linkage mechanism in a direction substantially perpendicular to the relative linear movement of the force transmission parts, and arranged to come into contact with an object, providing power transmission, the linkage mechanism having a guide with geometry that controls a given movement when creating a force interaction engagement with at least one of the parts for transmitting force and converts this relative linear variable parts for transmitting force to the extension and retraction of the lever mechanism and linear movement of the first element for transmitting force, while the guide is made in the form of a wedge, which is integral with the shoulder of the lever mechanism, and the guide surface of the wedge interacts with the wheel, which is part of the part for force transmission, carry out the initial extension of the actuator, acting with constant force, by performing relative linear movement of the parts to transmit power to each other and the interaction of the geometry of the control of movement with at least one of the parts for transmitting the force, as well as creating a movement force of the lever mechanism, oriented to extend the lever mechanism, and to create a substantially constant force transmitted by the lever mechanism on the first force transmission element carry out the continuation of the extension of the actuator, acting with constant force, by continuing the relative linear movement of the parts to transmit power until reaching annogo intermediate angular position of the lever mechanism and to the separating movement control geometry and specify at least one part for transmission power; carry out further extension of the actuator, acting with constant force, by continuing the relative linear movement of the parts for transmitting the force, so that the parts for transmitting the force act directly on the linkage, until the desired extension of the linkage and the desired movement of the first element for transmitting the force are achieved. 2. A method of applying to the object essentially constant force, according to which an actuator acting with constant force is located close to the object, while the actuator acting with constant force has first and second parts for transmitting force, linearly movable relative to each other friend, and also has a movement control element located at least on one of the first and second parts for transmitting force, and, further, has a pair of arms of the linkage mechanism, each of which has a first end, hinges connected to the corresponding one of the first and second parts for transmitting forces, which have second ends, pivotally interconnected and forming an articulated lever mechanism having angular movement from a retracted position to an extended position for transmitting force, and also a guide for controlling the movement of the lever mechanism arm having a predetermined geometry for controlling movement and engaging to provide movement of the linkage mechanism, with a movement control element in those reading a part of the process of extending the articulated linkage mechanism from the retracted position to the extended position; carry out the initial extension of the actuator, acting with constant force, from the retracted position of the articulated lever mechanism by linearly moving at least the first of the parts for transmitting force to the second part for transmitting force, the interaction of the movement control element with a guide serving to control the movement of the lever mechanism arm creating a movement force of the linkage mechanism oriented to extend the articulated linkage and creating substantially constant force transmitted by the linkage; carry out the continuation of the extension of the actuator, acting with constant force, by means of force interaction of the guide, which serves to control the movement of the lever arm of the lever mechanism, and the movement control element, until reaching a predetermined intermediate angular position of the articulated lever mechanism and to separate the guide, which serves to control the movement of the lever arm of the lever , and a motion control; carry out further extension of the actuator, acting with constant force, by further moving the first and second parts to transfer forces to each other and applying linear force from the parts to transfer forces directly to the pair of arms of the linkage; carry out the assignment of the actuator, acting with constant force, from the extended state by means of relative linear movement of the parts for transmitting the force from each other, while the parts for transmitting the force provide the removal of the articulated linkage. 3. An actuator operating with essentially constant force, comprising a pair of parts for transmitting force, made with the possibility of relative linear movement; a lever mechanism receiving force from the parts for transmitting force and having an element for transmitting the force, movable by the lever mechanism in a direction essentially perpendicular to the relative linear movement of the parts for transmitting the force, located with the possibility of transmitting the force of contact with the object; wherein the linkage mechanism has at least one guide for controlling the movement, made with a given geometry, is in engagement with the force interaction of at least one of the parts for transmitting force and converts the relative linear movement of the parts for transmitting force into the extension and retraction of the linkage and linear movement of the element for transmitting force, while the guide is made in the form of a wedge, which is integral with the lever arm, and the wedge surface interacts with the wheel, which is part of the part for transmitting force. 4. An actuator operating with essentially constant force, comprising a pair of parts for transmitting forces having the ability to linearly move relative to each other from positions of a given maximum distance between them to a position of a specified minimum distance between them; a linear mechanism for transmitting force, providing a forced linear movement of parts for transmitting force to the position of a given maximum distance between them and a given minimum distance between them and from these positions; a motion control located on at least one of the pair of parts for transmitting force; at least one pair of arms of the linkage mechanism, each of which has a first end and a second end, wherein the first ends of the linkage arm arms are pivotally connected to respective ends of the power transmission parts, and the second ends of the linkage arm arms are pivotally connected to each other, at least one pair of arms of the linkage mechanism is arranged to be located in an angular position with a predetermined minimum angle when parts are located for transmitting force at a predetermined maximum distance from each other and with a predetermined maximum angle when finding parts for transmitting force at a given minimum distance from each other; a lever mechanism arm guide formed by at least one of the arm mechanism arms and engaged to engage the mechanism arm with a movement control member when extending the arm mechanism arms from a predetermined minimum angle to a predetermined intermediate angle; wherein the parts for transmitting the force transmit the movement force of the linkage mechanism directly to the first and second arms of the linkage mechanism when the arms of the linkage mechanism extend from a predetermined intermediate angle to a predetermined maximum angle. 5. An actuator operating with constant force, comprising a pair of parts for transmitting force, at least one of which is made with the possibility of linear movement to ensure relative positions at specified maximum and minimum distances between the parts; a linear force transmission mechanism linearly moving at least one part for transmitting force to the positions of the specified maximum and minimum distances between and from these positions; at least one movement control element located on at least one of the pair of parts for transmitting force; at least two pairs of arms of the lever mechanism, each of which has a first end and a second end, the first ends of the arms of the lever mechanism pivotally connected to one of the parts for transmitting force, and the second ends of the arms of the lever mechanism pivotally connected to each other, each of the pairs of shoulders of the lever mechanism makes an angular movement and is arranged to be positioned at an angle from the minimum angles when the parts are located to transmit power at a given maximum distance from each other to maximum angles when finding parts for transmitting force at a given minimum distance from each other; driven traction elements mounted on each of the pairs of shoulders of the lever mechanism and placed with the possibility of transmitting the engagement force with the surface for traction movement of the mechanism acting with constant force along the surface; at least one linkage arm drive device formed by at least one of the linkage arms and engaged to engage the linkage with a movement control during at least a portion of the angular movement of the linkage arms from a predetermined minimum angle to a predetermined angle maximum angle.

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