Abstract:
A downhole tool includes a logging tool. The logging tool includes a spring integral with a sensor. The spring applies the sensor to a formation wall. Additionally, the spring includes a groove formed along a neutral axis thereof. In addition, a wire is located within the groove and is operatively connected with the sensor and at least one other component of the logging tool.

Description:
BACKGROUND 
       [0001]    The present disclosure relates generally to the field of downhole tools and, more particularly, to a downhole caliper tool system. 
         [0002]    This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present techniques, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions. 
         [0003]    In hydrocarbon drilling operations, downhole tools may be lowered into a borehole to perform specific tasks. For example, a logging string system may be lowered through a drill string or downhole tubular. The logging string system includes a logging tool that takes various measurements, which may range from common measurements such as pressure or temperature to advanced measurements such as rock properties, fracture analysis, fluid properties in the wellbore, or formation properties extending into the rock formation. Some logging tools contact the borehole to obtain various measurements. 
         [0004]    In certain cases, the logging tool includes mechanical linkages and components to facilitate expansion of the logging tool after the logging tool passes through the drill string or downhole tubular. The mechanical linkages are exposed to borehole pressures, as well as fluids having high viscosities or particulates. The borehole environment may degrade the logging tool, thereby resulting in more frequent repairs or replacements. 
       SUMMARY OF DISCLOSED EMBODIMENTS 
       [0005]    A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below. 
         [0006]    In an embodiment, a downhole tool includes a logging tool. The logging tool includes a spring integral with a sensor. The spring applies the sensor to a formation wall. Additionally, the spring includes a groove formed along a neutral axis thereof. In addition, a wire is located within the groove and is operatively connected with the sensor and at least one other component of the logging tool. 
         [0007]    In another embodiment, a downhole tool includes a linkage-less caliper tool. The linkage-less caliper tool includes a spring that drives radial movement of a sensor disposed on the spring. In addition, the radial movement of the sensor is relative to a logging tool axis of a logging tool positioned in a borehole. 
         [0008]    In a further embodiment, a downhole tool includes a drill string that may be disposed in a borehole in a formation. The downhole tool also includes a drill bit coupled to an end of the drill string. The drill bit engages the formation to form the borehole. Moreover, the downhole tool includes a logging tool positioned within the drill string. The logging tool may extend through the drill bit. Additionally, the logging tool includes a spring having a groove along a neutral axis of the spring. 
         [0009]    Various refinements of the features noted above may exist in relation to various aspects of the present disclosure. Further features may also be incorporated in these various aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to one or more of the illustrated embodiments may be incorporated into any of the above-described aspects of the present disclosure alone or in any combination. Again, the brief summary presented above is intended just to familiarize the reader with certain aspects and contexts of embodiments of the present disclosure without limitation to the claimed subject matter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which: 
           [0011]      FIG. 1  shows a schematic view of an embodiment of a drilling system, in accordance with various embodiments of the present disclosure; 
           [0012]      FIG. 2  shows a perspective view of an embodiment of a logging tool having a caliper tool, in accordance with various embodiments of the present disclosure; 
           [0013]      FIG. 3  shows a partial schematic top view of an embodiment of a sensor positioned on a spring of the caliper tool of  FIG. 2 , in accordance with various embodiments of the present disclosure; 
           [0014]      FIG. 4  shows a partial schematic cross-sectional side view of the sensor of  FIG. 3 , in accordance with various embodiments of the present disclosure; 
           [0015]      FIG. 5  shows a partial schematic top view of an embodiment of a groove formed in the caliper tool of  FIG. 2 , in accordance with various embodiments of the present disclosure; 
           [0016]      FIG. 6  shows a partial perspective cross-sectional view of the groove of  FIG. 5 , in accordance with various embodiments of the present disclosure; 
           [0017]      FIG. 7  shows a partial schematic cross-sectional view of the caliper tool of  FIG. 2  disposed in a borehole, in which a sensor contacts a sidewall of the borehole, in accordance with various embodiments of the present disclosure; and 
           [0018]      FIG. 8  shows a partial schematic cross-sectional view of the caliper tool of  FIG. 2  disposed in a borehole, in which bumpers contact a sidewall of the borehole, in accordance with various embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    One or more specific embodiments of the present disclosure will be described below. These described embodiments are just examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these embodiments, some features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would still be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
         [0020]    When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. 
         [0021]    Embodiments of the present disclosure are directed toward a logging tool having a caliper tool with springs that enable radial movement of a sensor disposed on the caliper tool. In certain embodiments, the sensor moves radially with respect to the logging tool axis, via the springs. The spring may include an integrated sensor that takes borehole measurements. For example, the sensor may couple two spring sections to form the caliper tool. In certain embodiments, the spring may extend through a housing. In other embodiments, the spring includes a groove having a generally T-shaped cross section. The groove houses communication cables for communicatively coupling the sensor to the logging tool. Additionally, in certain embodiments, the spring includes bumpers that contact the sidewall. Spring sections between the bumpers may drive the sensor away from the sidewall while the bumpers are engaged with the sidewall. 
         [0022]    Referring now to  FIG. 1 , an embodiment of a downhole drilling system  10  (e.g., drilling system) comprises a rig  12  and a drill string  14  coupled to the rig  12 . The drill string  14  includes a drill bit  16  at a distal end that may be rotated to engage a formation and form a borehole  18 . As shown, the borehole  18  includes a borehole sidewall  20  and an annulus  22  between the borehole  18  and the drill string  14 . Moreover, a bottom hole assembly (BHA)  24  is positioned at the bottom of the borehole  18 . The BHA  24  may include a drill collar  26 , stabilizers  28 , or the like. 
         [0023]    During operation, drilling mud or drilling fluid is pumped through the drill string  14  and out of the drill bit  16 . The drilling mud flows into the annulus  22  and removes cuttings from a face of the drill bit  16 . Moreover, the drilling mud may cool the drill bit  16  during drilling operations. In the illustrated embodiment, the drilling system  10  includes a logging tool  30 . As shown, the logging tool  30  extends through the drill bit  16 . The logging tool  30  conducts downhole logging operations to obtain various measurements in the borehole  18 . For example, the logging tool  30  may include sensors (e.g., resistive, nuclear, seismic, etc.) to determine various borehole and/or fluidic properties. Additionally, the logging tool  30  may include sampling tools to obtain core samples, fluid samples, or the like from the borehole  18 . Moreover, in certain embodiments, the logging tool  30  includes mechanical measurement devices, such as calipers, to obtain measurements of the borehole  18 . While the illustrated embodiment includes a substantially vertical borehole  18 , in other embodiments the borehole  18  may be deviated or substantially horizontal. Additionally, while the illustrated embodiment includes the logging tool  30  extending from the drill bit  16 , in other embodiments the logging tool  30  may be a separate sub coupled to the drill string  14 . 
         [0024]      FIG. 2  shows an isometric view of an embodiment of the logging tool  30 . In the illustrated embodiment, the logging tool  30  includes mechanical calipers  32  (e.g., caliper tool, calipers) and sensors  34 . In certain embodiments, the calipers  32  move radially with respect to a logging tool axis  36 . That is, the sensor on the calipers may be driven to move radially inward and radially outward, with respect to the logging tool axis  36 . The calipers  32  may contact the sidewall  20  of the borehole  18  to obtain various measurements. For example, the calipers  32  may be utilized to determine the diameter of the borehole  18 . Additionally, in certain embodiments, the calipers  32  may press the sensors  34  against the sidewall  20  of the borehole  18 , thereby enabling additional measurements of the formation (e.g., resistivity, nuclear, etc.). However, in other embodiments, the sensors  34  may be non-contact sensors and may not contact the sidewall  20  of the borehole  18  to obtain formation measurements. 
         [0025]    In the illustrated embodiment, the calipers  32  include springs  38  to drive the calipers  32  radially outward with respect to the logging tool axis  36 . That is, the springs  38  are biased to enable expansion of the calipers  32  after the logging tool  30  is extended through the drill bit  16 . In certain embodiments, the springs  38  may be bow springs. Moreover, in certain embodiments, the springs  38  may be utilized with other downhole tools. For example, the springs  38  may be coupled to stabilizers, centralizers, fishing tool, or the like. However, in other embodiments, the calipers  32  may include mechanical actuators to facilitate deployment of the calipers  32 . For example, the mechanical actuators may block expansion of the calipers  32  until activated. In embodiments where the logging tool  30  extends through the drill bit  16 , the mechanical actuators may block deployment of the calipers  32  until the logging tool  30  is through the drill bit  16 . 
         [0026]    As shown, the calipers  32  are coupled to the logging tool  30  at a first location  40  and at a second location  42 . The first location  40  is axially farther up the borehole  18  (e.g., closer to the surface) than the second location  42 . As will be described below, the first location  40  and the second location  42  may be rigidly fixed to the logging tool  30 . However, in other embodiments, the second location  42  may move and/or slide axially along the logging tool axis  36 . For example, the second location  42  may be positioned on a hub  44  positioned radially about a tool string  46  of the logging tool  30 . 
         [0027]    In the illustrated embodiment, four calipers  32  are coupled to the logging tool  30 . As shown, the calipers  32  are positioned approximately 90 degrees offset from the adjacent calipers  32 . As a result, four measurements may be obtained indicative of the radius of the borehole  18  with respect to the logging tool axis  36 . However, in other embodiments, more or fewer calipers  32  may be utilized. For example, 2, 3, 5, 6, 7, 8, or any suitable number of calipers  32  may be positioned on the tool string  46  to obtain borehole measurements. Moreover, in the illustrated embodiment, each hub  44  is coupled to two calipers  32 , facilitating multiple independent measurements of the borehole  18 . However, in other embodiments, more of fewer hubs  44  may be utilized. For example, each caliper  32  may be independently coupled to a single hub  44 . 
         [0028]    Returning to the springs  38 , in the illustrated embodiment, bumpers  48  are disposed on each side of the sensors  34 . In certain embodiments, the bumpers  48  are equidistant from the sensors  34 . However, in other embodiments, the bumpers  48  may be located in different locations for anticipated borehole conditions. Furthermore, while two bumpers  48  are shown on each caliper  32 , in other embodiments, the calipers  32  may include 1, 3, 4, 5, 6, 7, 8, or any suitable number of bumpers  48 . As will be described below, in certain embodiments, the bumpers  48  extend radially farther from the logging tool axis  36  than the sensors  34 . As a result, the bumpers  48  may contact the sidewall  20  or an interior surface of the drill string  14  before the sensors  34  while the calipers  32  extend radially out and away from the logging tool axis  36 . For example, in certain embodiments, the logging tool  30  may be transported through a tubular to into the borehole  18 . While inside the tubular, the bumpers  48  may contact the interior surface of the tubular and urge the sensors  34  away from the interior surface of the tubular. 
         [0029]      FIG. 3  is a partial top view of the sensor  34  coupled to the springs  38  of the caliper  32 . As shown, the sensor  34  includes a housing  50  that stores and fluidly isolates electronic components and/or measurement tools. For example, the housing  50  may include a nuclear measurement source and receiver that emits energy into the formation and receives energy emitted from the formation. Moreover, the housing  50  may include communication electronics to transmit data acquired by the sensor  34 . For example, the communication electronics may transmit the data to a telemetry device that transmits the data to a surface controller. 
         [0030]    In the illustrated embodiment, the housing  50  has a housing width  52  that is larger than a spring width  54 . However, in other embodiments, the housing width  52  may be less than the spring width  54  or equal to the spring width  54 . It will be appreciated that the housing width  52  of the housing  50  may be particularly selected to accommodate the electronics within the housing  50  and/or due to borehole conditions. Additionally, the housing  50  extends a length  56  perpendicular to a spring axis  58  (e.g., a neutral axis). The length  56  may be particularly selected to accommodate the electronics within the housing  50 . For example, the length  56  may be five percent the length of the springs  38 , ten percent the length of the springs  38 , fifteen percent the length of the springs  38 , twenty percent the length of the springs  38 , thirty percent the length of the springs  38 , forty percent the length of the springs  38 , or any suitable percentage of the length of the springs  38 . 
         [0031]    As shown in  FIG. 3 , the housing  50  is coupled to the springs  38  at a first end  60  and a second end  62 . For example, fasteners  64  may couple the springs  38  to the housing  50 . In certain embodiments, the fasteners  64  are screws, bolts, clamps, or the like. In the illustrated embodiment, the spring  38  is formed from two springs  38   a,    38   b  (e.g., spring sections). Each spring  38   a,    38   b  is independently fastened to the housing  50  via the fasteners  64 . However, in other embodiments, a single spring  38  may extend through the length  56  of the housing  50 . Accordingly, the sensor  34  may be coupled to the spring  38  to form the caliper  32  having an integrated sensor  34 . 
         [0032]      FIG. 4  is a partial cross-sectional view of the sensor  34  positioned on the spring  38 . As described above, the springs  38   a,    38   b  are coupled to the housing  50  at the first end  60  and the second end  62 , respectively. In the illustrated embodiment, the springs  38   a,    38   b  extending into the housing  50  are engaged by the fasteners  64  to couple the sensor  34  to the spring  38 . However, as mentioned above, in certain embodiments, the spring  38  may extend through the length  56  of the housing  50 . 
         [0033]    As shown, a housing depth  66  of the housing  50  is greater than a spring depth  68  of the spring  38  and houses various electronic or mechanical components of the sensor  34 . For instance, in the illustrated embodiment, the sensor  34  includes a sensing device  70 . The sensing device  70  may be a device that obtains borehole measurements. For example, the sensing device  70  may be a nuclear sensor, a resistivity sensor, a seismic sensor, or the like. In certain embodiments, the sensing device  70  may include both a source (e.g., radioactive isotope, electrical source, etc.) and a transceiver (e.g., a device to send and emit energy and/or data). Moreover, the sensing device  70  may be a contact sensor (e.g., contacts the sidewall  20 ) or a non-contact sensor. 
         [0034]    The sensing device  70  is communicatively coupled to a controller  72  having a processor  74  and a memory  76 . The memory  76  is a non-transitory (not merely a signal), computer-readable media, which may include executable instructions that may be executed by the processor  74 . For example, the controller  72  may receive a signal from the sensing device  70  indicative of a borehole property (e.g., a resistivity measurement of the formation). In certain embodiments, the memory  76  may store the signal for later evaluation. However, in other embodiments, the processor  74  may evaluate the signal for use during drilling, completion, cementing, or other borehole operations. Additionally, in some embodiments, the controller  72  may send the signal to a communication device  78  for transmission from the sensor  34  to the drill string  14  and/or a surface controller. For example, the communication device  78  may include a wired or wireless communication system (e.g., Ethernet, fiber optic, cellular, mud pulse, etc.) to transmit data from the sensor to other parts of the drill string  14  and/or a surface controller. Accordingly, data acquired by the sensor  34  may be utilized during borehole operations. As described above, the springs  38  of the calipers  32  may include integrated sensors  34  for obtaining borehole measurements during borehole operations. For example, the sensors  34  may be fastened to the springs  38  and urged to move radially, relative to the logging tool axis  36 , with the calipers  32 . 
         [0035]      FIG. 5  is a partial top view of an embodiment of the spring  38 . In the illustrated embodiment, the spring  38  includes a groove  90  extending along the spring axis  58 . The groove  90  extends a first depth  92  into the spring  38 , transverse to the spring axis  58 . In certain embodiments, the first depth  92  is twenty percent of the spring depth  68 . However, in other embodiments, the first depth  92  may be thirty percent of the spring depth  68 , forty percent of the spring depth  68 , fifty percent of the spring depth  68 , sixty percent of the spring depth  68 , seventy percent of the spring depth  68 , or any suitable percentage of the first depth  92 . The groove  90  further includes a slot  94  and a channel  96  substantially shaped like a “T”. However, in other embodiments, the slot  94  and channel  96  may be different shapes. For example, the groove may have a substantially I-shaped cross section, H-shaped cross section, V-shaped cross section, or any other suitable shape. 
         [0036]    In certain embodiments, the groove  90  may be utilized to provide a routing path for wired communication to and/or from the sensor  34 . For example, communication cables (e.g., fiber optics, Ethernet, etc.) may be positioned within the slot  94  and/or the channel  96  to communicatively couple the sensor  34  to the drill string  14 . In certain embodiments, the communication cables may be insulated and/or coated. For example, the communication cables may be polymer-coated (e.g., TEFLON, polytetrafluoroethylene, plastics, polymers). By coating the communication cables, friction between the communication cables and the groove  90  may be reduced. As a result, the communication cables are secured within the spring  38 , thereby decreasing the likelihood of wear due to direct exposure to the borehole environment. Additionally, forming the groove  90  in the springs  38  obviates additional attachment coupled to the spring  38  (e.g., welded, bolted, etc.) to protect and/or route the communication cables. 
         [0037]    Inclusion of the groove  90  utilizes a reduced portion of material comprising the spring  38 . As a result, the bending strength of the spring  38  may be substantially equal to a spring not having the groove  90 . However, a small amount of material may be added to the spring  38  to maintain bending strength. As shown, the groove  90  extends along the spring axis  58 . Because the groove  90  is along the spring axis  58 , length compensation of the communication cables may be reduced or eliminated because the spring axis  58  length remains substantially the same. 
         [0038]      FIG. 6  is a partial cross-sectional perspective view of the groove  90  positioned within the spring  38 . As mentioned above, the groove  90  includes the generally T-shaped channel  96  and slot  94 . Moreover, communication cables  98  are positioned within the channel  96 . The channel  96  is sized to accommodate the size of the communication cables  98 , but to reduce and/or eliminate substantial movement of the communication cables  98  to reduce and/or eliminate fretting or other potentially degrading contact between the communication cables  98  and the spring  38 . Moreover, limiting the movement of the communication cables  98  may reduce noise in the signal being transmitted via the communication cables  98 . As shown, the channel  96  has a channel width  100  that is larger than a slot width  102  of the slot  94 . As a result, upward movement (e.g., movement transverse to the spring axis  58 ) is substantially blocked because of the solid portion of the spring  38  positioned above a substantial portion of the channel  96 . In the illustrated embodiment, the groove  90  extends the length of the spring  38 . However, in other embodiments, the groove  90  may only extend along a partial length of the spring  38 . For example, in embodiments where the spring  38  is formed from multiple pieces, the groove  90  may be positioned in the spring  38   a  and not in the spring  38   b . Additionally, while the groove  90  is described above as being incorporated in the spring  38 , in other embodiments the groove  90  may be incorporated in the drill string  14 , in linkages positioned along the drill string  14 , or any other suitable location. 
         [0039]    In certain embodiments, the groove  90  may be machined into the material utilized to form the spring  38 . For example, the groove may be cut (e.g., laser cut, water cut, etc.) along the spring axis  58 . Then, the spring  38  may be formed, heated treated, and the like. Accordingly, the spring  38  may be formed with properties particularly selected to accommodate the groove  90 . However, in other embodiments, the groove  90  may be machined into the spring  38  after the spring forming process. 
         [0040]      FIG. 7  is a partial cross-sectional view of an embodiment of the logging tool  30  disposed in the borehole  18 . In the illustrated embodiment, the calipers  32  are radially extended, relative to the logging tool axis  36 . That is, the spring force drives the calipers  32  radially outward until the sidewall  20  is contacted or the maximum elongation of the springs  38  is reached. As shown, the force of the springs  38  drives the sensor  34  against the sidewall  20  of the borehole  18  at a first distance  104 . Accordingly, the sensor  34  may obtain measurements from the borehole  18 . As shown, the first distance  104  extends farther than the position of the bumpers  48 . As will be described below, in embodiments where the sidewall  20  is at the second distance  106  the bumpers  48  may contact the sidewall  20  before the sensor  34 . However, in other embodiments, the sidewall  20  may be replaced by the interior surface of the tubular as the logging tool  30  is disposed within the borehole  18 . 
         [0041]    In operation, the caliper tool  32  (e.g., caliper) may be activated when the logging tool  30  is extended through the drill bit  16 . Thereafter, the spring force may drive the sensor  34  toward the sidewalls  20  of the borehole  18 , with respect to the logging tool axis  36 . Additionally, in certain embodiments, the logging tool  30  may remain extended through the drill bit  16  while the drill string  14  is removed from the borehole  18 . For example, the caliper tool  32  may continually take measurements of the borehole  18  as the drill string  14  is removed from the borehole  18  because the sidewall  20  will continue to act on the calipers  32  (e.g., enable compression or expansion of the springs  38 ) as the drill string  14  is removed from the borehole  18 . 
         [0042]      FIG. 8  is a partial cross-sectional view of an embodiment of the logging tool disposed in the borehole  18 . As shown, the sidewall  20  is positioned at the second distance  106  and the bumpers  48  contact the sidewall  20 . However, as described above, in certain embodiments the bumpers  48  may contact the interior surface of the tubular as the logging tool  30  is disposed within the borehole  18 . Additionally, in the illustrated embodiment, the spring  38  is formed from multiple sections. As described above, the spring  38  may include sections of spring material. A first spring section  108  and a second spring section  110  are generally convex, relative to the logging tool axis  36 . That is, the first and second spring sections  108 ,  110  drive the sensor  34  toward the sidewall  20 . However, a third spring section  112  and a fourth spring section  114  are generally concave, relative to the logging tool axis  36 . Accordingly, the third and fourth spring sections  112 ,  114  drive the sensor  34  away from the sidewall  20  (or in other embodiments, the interior surface of the tubular) and toward the logging tool axis  36 . 
         [0043]    As shown, the transition between the first and third spring sections  108 ,  112  and the second and fourth spring sections  110 ,  114  is located at the bumpers  48 . As the bumpers  48  contact the sidewall  20 , the third and fourth spring sections  112 ,  114  bias the sensor  34  away from the sidewall  20 . Accordingly, the sensor  34  is suspended within the borehole  18  and does not contact the sidewall  20 . Moreover, in other embodiments, the sensor  34  may be suspended within the tubular and not contact the interior surface of the tubular. In certain embodiments, the sensor  34  may obtain fluid samples in the annulus  22  while the bumpers  48  are in contact with the sidewall  20 . In certain embodiments, the third and fourth spring sections  112 ,  114  bias the sensor  34  toward the sidewall  20  while the bumpers  48  are not in contact with the sidewall  20 . 
         [0044]    As described above, the caliper  32  may include springs  38  that radially move the sensor  34  relative to the logging tool axis  36 . In certain embodiments, the springs  38  include the sensor  34  integrated into the springs  38 . That is, the sensor  34  may join two springs via fasteners  64  to form the caliper  32 . Additionally, in other embodiments, the springs  38  may include the groove  90  to route communication cables  98  from the sensor  34  to the drill string  14 . The groove  90  may be positioned along the spring axis  58 . Furthermore, the springs  38  may include bumpers  48  that contact the sidewall  20 . The bumpers  48  may be positioned on different sides of the sensor  34  and contact the sidewall  20  before the sensor  34 . As a result, the spring sections  112 ,  114  may drive the sensor  34  away from the sidewall  20 . 
         [0045]    The specific embodiments described above have been shown by way of example, and it should be understood that these embodiments may be susceptible to various modifications and alternative forms. It should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover modifications, equivalents, and alternatives falling within the spirit and scope of this disclosure.