WO2010047721A1

WO2010047721A1 - Seal assembly for a rotary earth bit

Info

Publication number: WO2010047721A1
Application number: PCT/US2008/081197
Authority: WO
Inventors: Gregory W. Peterson
Original assignee: Atlas Copco Secoroc Llc
Priority date: 2008-10-23
Filing date: 2008-10-24
Publication date: 2010-04-29
Also published as: US20100102513A1

Abstract

An earth bit includes a cutting cone rotatably mounted to a lug, and a seal assembly positioned to provide a seal between the cutting cone and lug. The seal assembly includes first and second rigid rings, and a first elastomeric sealing ring which carries the first rigid ring. The second rigid ring rotates in response to the rotation of the first elastomeric sealing ring, so that the second rigid ring is less likely to lock.

Description

SEAL ASSEMBLY FOR A ROTARY EARTH BIT

BACKGROUND OF THE INVENTION

Field of the Invention

[0001] This invention relates generally to a seal assembly for providing a seal between a lug and cutting cone of a rotary earth bit.

Description of the Related Art

[0002] An earth bit is commonly used to bore holes into a formation. Such holes may be bored for many different reasons, such as drilling for oil, minerals and geothermal steam. There are several different types of earth bits that are used to bore holes. One type is a rotary earth bit and, in a typical setup, it includes three cutting cones rotatably mounted to a corresponding lug. The lugs form an earth bit body and, as the earth bit body is rotated in the bore hole, the cutting cones rotate in response to contacting the formation.

[0003] In normal use, the earth bit contacts rock formations while being exposed to extreme conditions, such as high temperatures and pressures. As a result, the earth bit tends to wear down. A lug is especially prone to wearing down because of friction between it and its corresponding cutting cone. Lubricant is typically retained between the lug and cutting cone with an earth bit seal to reduce the friction between the lug and cutting cone. The earth bit seal also restricts the flow of debris to the region between the lug and cutting cone, which reduces the friction therebetween. Retaining lubricant and keeping debris from between the lug and cutting cone increases the life of the earth bit. [0004] The earth bit seal is generally in rotating contact with the lug and/or cutting cone. The surface portion of the earth bit seal in rotating contact with the lug or cutting cone is typically known as a dynamic sealing surface. The earth bit seal and cutting cone form a dynamic seal when the earth bit seal and cutting cone rotate relative to each other. Further, the earth bit seal and lug form a dynamic seal when the earth bit seal rotates relative to the lug. The surface portion of the earth bit seal in static contact with the earth bit lug or cutting cone is typically known as a static sealing surface. The earth bit seal and cutting cone form a static seal when the earth bit seal and cutting cone do not rotate relative to each other. Further, the earth bit seal and lug form a static seal when the earth bit seal does not rotate relative to the lug.

[0005] One type of earth bit seal includes an elastomeric 0- ring. The elastomeric 0-ring typically experiences the extreme conditions mentioned above, which can cause it to become impregnated with debris, especially if the 0-ring forms a part of the dynamic sealing surface. An elastomeric 0-ring impregnated with debris is more likely to tear and lose elastomeric material, which inhibits its ability to form a seal. Further, an elastomeric 0-ring impregnated with debris operates as an abrasive ring which can undesirably remove material from the lug or cutting cone it is dynamically sealed with. A groove in the lug or cutting cone is typically formed in response to the material being removed by the elastomeric 0-ring impregnated with debris. It is more difficult for the 0-ring to provide a seal between the lug or cutting cone if a groove is formed in the lug or cutting cone.

[0006] Another type of earth bit seal includes a metal face seal engaged with an elastomeric 0-ring. The metal face seal dynamically engages a surface of either the lug or cutting cone, or another metal face seal. Further, a static seal is typically formed between the metal face seal and elastomeric 0-ring. The metal face seal protects the elastomeric 0-ring from becoming impregnated with debris. Hence, the metal face seal reduces the amount of elastomeric material removed from the elastomeric 0-ring. The metal face seal does not become impregnated with debris as easily as seals which include elastomeric materials. Hence, the metal face seal is less likely to operate as an abrasive ring and remove material from the cutting cone or lug it is dynamically sealed with. [0007] However, mud packing around the metal face seal can cause it to lock and undesirably form a dynamic seal with the elastomeric 0-ring, and a static seal with the cutting cone or lug. For example, mud packing can cause the metal face seal to lock and form a static seal with the cutting cone when it is desirable for the metal face seal to form a dynamic seal with the cutting cone. In another example, mud packing can cause the metal face seal to lock and form a static seal with the lug when it is desirable for the metal face seal to form a dynamic seal with the lug. When the metal face seal forms a static seal with the lug, the seal assembly undesirably operates as an elastomeric 0-ring seal and can experience the problems discussed above.

[0008] Another problem with metal face seals is that the seal formed by it can break in response to the misalignment of the cutting cone and lug. When a seal breaks, lubricant is less likely to be retained between the lug and cutting cone and debris is more likely to enter the region between the lug and cutting cone. Misalignment of the lug and cutting cone is more likely to occur when the lug and cutting cone are not properly lubricated. Further, misalignment of the cutting cone and lug is more likely to occur when the clearances between the components of the rotary earth bit increase.

[0009] Thus, it is desirable to provide an earth bit seal which provides a better seal between the lug and cutting cone of a rotary earth bit.

BRIEF SUMMARY OF THE INVENTION

[0010] The present invention provides a seal assembly, which includes a first rigid ring and a first elastomeric sealing ring which includes an arm coupled with the first rigid ring. In accordance with the invention, the elastomeric sealing ring is repeatably moveable between flexed and unflexed conditions, wherein the first rigid ring moves in response to the first elastomeric sealing ring moving between the flexed and unflexed conditions. [0011] The seal assembly can include many other features. In some embodiments, the seal assembly includes a second rigid ring carried by the first elastomeric sealing ring. The second rigid ring can include an outwardly facing groove which receives the arm, wherein the arm restricts the rotation of the first rigid ring relative to the first elastomeric sealing ring. In some embodiments, the seal assembly includes a second elastomeric sealing ring carried by the second rigid ring, wherein the second elastomeric sealing ring extends beyond a surface opposed to a dynamic sealing surface of the second rigid ring.

[0012] In some embodiments, the first elastomeric sealing ring includes a protrusion carried by the arm, the protrusion restricts the rotation of the first rigid ring relative to the first elastomeric sealing ring. In some embodiments, the protrusion extends beyond a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. In other embodiments, the protrusion terminates flush with a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring.

[0013] The present invention provides a seal assembly, which includes first and second rigid rings, and a first elastomeric sealing ring which carries the first rigid ring. In accordance with the invention, the first elastomeric sealing ring restricts the rotation of the second rigid ring relative to the first rigid ring, so that the second rigid ring rotates in response to the rotation of the first rigid ring. In this way, the second rigid ring is less likely to lock.

[0014] The seal assembly can include many other features. In some embodiments, the seal assembly includes a second elastomeric sealing ring carried by the second rigid ring. The second elastomeric sealing ring extends beyond a surface opposed to a dynamic sealing surface of the second rigid ring. In some embodiments, the first elastomeric sealing ring includes an arm which extends towards the second rigid ring. The second rigid ring can include an outwardly facing groove which receives the arm. The first elastomeric sealing ring can include a protrusion carried by the arm, wherein the protrusion engages the second rigid ring. In some embodiments, the protrusion extends beyond a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. In other embodiments, the protrusion terminates flush with a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. In some embodiments, the protrusion terminates proximate with a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring.

[0015] The present invention provides an earth bit, which includes a lug and cutting cone, and a seal assembly which includes first and second rigid rings, and a first elastomeric sealing ring which carries the first rigid ring. In accordance with the invention, the second rigid ring rotates in response to the rotation of the first elastomeric sealing ring. In this way, the second rigid ring is less likely to lock.

[0016] In some embodiments, the first elastomeric sealing ring forms a static sealing surface with the cutting cone, and the second rigid ring forms a dynamic sealing surface with the lug. In other embodiments, the first elastomeric sealing ring forms a static sealing surface with the lug, and the second rigid ring forms a dynamic sealing surface with the cutting cone. [0017] The earth bit can include many other features. In some embodiments, the seal assembly includes a second elastomeric sealing ring carried by the second rigid ring, the second elastomeric sealing ring extending beyond a surface opposed to a dynamic sealing surface of the second rigid ring. In some embodiments, the first elastomeric sealing ring includes an arm which extends towards the second rigid ring. The second rigid ring can include an outwardly facing groove which receives the arm. In some embodiments, the first elastomeric sealing ring includes a protrusion carried by the arm, wherein the protrusion engages the second rigid ring. In some embodiments, the protrusion extends beyond a surface opposed to a dynamic sealing surface of the second rigid ring. In other embodiments, the protrusion terminates flush with a surface opposed to a dynamic sealing surface of the second rigid ring. In some embodiments, the protrusion terminates proximate with a surface opposed to a dynamic sealing surface of the second rigid ring.

[0018] The present invention employs a method of providing a seal for an earth bit, which includes coupling a first elastomeric sealing ring and first rigid ring together, and coupling a second rigid ring to the first elastomeric sealing ring to form a seal assembly. In accordance with the invention, the first elastomeric sealing ring restricts the rotation of the second rigid ring relative to the first rigid ring. In this way, the second rigid ring is less likely to lock. The method includes positioning the seal assembly to form a seal between a cutting cone and lug. [0019] The method can include many other steps. In some embodiments, the step of coupling the second rigid ring and first elastomeric sealing ring together includes extending an arm through an outwardly facing groove of the second rigid ring. In some embodiments, the step of coupling the second rigid ring and first elastomeric sealing ring together includes extending a protrusion through a notch. In some embodiments, the protrusion extends beyond a surface of the second rigid ring, and, in other embodiments, the protrusion terminates flush with a surface of the second rigid ring. In some embodiments, the protrusion terminates proximate with the surface of the second rigid ring. The surface is opposed to a dynamic sealing surface of the second rigid ring. [0020] In some embodiments, the method includes positioning a second elastomeric sealing ring so it is carried by the second rigid ring. The second elastomeric sealing ring extends beyond a surface opposed to a dynamic sealing surface of the second rigid ring. The second elastomeric sealing ring can engage the cutting cone in the embodiments in which the first elastomeric sealing ring forms a static sealing surface with the cutting cone. Further, the second elastomeric sealing ring can engage the lug in the embodiments in which the first elastomeric sealing ring forms a static sealing surface with the lug.

[0021] Further features and advantages of the invention will be apparent to those skilled in the art from the following detailed description, taken together with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. Ia is a perspective view of a rotary earth bit. [0023] FIG. Ib is a cut-away view of the rotary earth bit of FIG. Ia taken along a cut-line Ib-Ib.

[0024] FIGS. 2a and 2b are top and bottom perspective views, respectively, of one embodiment of an elastomeric sealing ring, in accordance with the invention.

[0025] FIGS. 3a and 3b are top and bottom perspective views, respectively, of another embodiment of an elastomeric sealing ring, in accordance with the invention.

[0026] FIGS. 4a and 4b are top and bottom perspective views, respectively, of one embodiment of an elastomeric sealing ring, in accordance with the invention.

[0027] FIGS. 5a and 5b are top and bottom perspective views, respectively, of one embodiment of a rigid dynamic sealing ring, in accordance with the invention.

[0028] FIGS. 6a and 6b are top and bottom perspective views, respectively, of one embodiment of a rigid dynamic sealing ring, in accordance with the invention.

[0029] FIGS. 7a and 7b are top and bottom perspective views, respectively, of a rigid reinforcement ring, in accordance with the invention .

[0030] FIG. 8 is a cut-away side view of the rotary earth bit of FIGS. Ia and Ib, which includes a seal assembly, in accordance with the invention.

[0031] FIGS. 9a and 9b are top and bottom exploded perspective views of the seal assembly of FIG. 8.

[0032] FIGS. 10a and 10b are top and bottom perspective views of the elastomeric sealing ring of FIGS. 2a and 2b and rigid dynamic sealing ring of FIGS. 5a and 5b coupled together for use in the seal assembly of FIG. 8.

[0033] FIG. 11a is a close-up view of the seal assembly of FIG. 8, in accordance with the invention.

[0034] FIGS, lib and lie are cut-away side views of the seal assembly of FIG. 8 taken along a cut-line lla-lla of FIG. 11a, showing the seal assembly in unflexed and flexed conditions, respectively .

[0035] FIG. 12 is a cut-away side view of the rotary earth bit of FIGS. Ia and Ib, which includes another embodiment of a seal assembly, in accordance with the invention.

[0036] FIGS. 13a and 13b are top and bottom exploded perspective views of the seal assembly of FIG. 12.

[0037] FIGS. 14a and 14b are top and bottom perspective views of the elastomeric sealing ring of FIGS. 3a and 3b and the rigid dynamic sealing ring of FIGS. 5a and 5b coupled together for use in the seal assembly of FIG. 12.

[0038] FIG. 15a is a close-up view of the seal assembly of FIG. 12, in accordance with the invention.

[0039] FIGS. 15b and 15c are cut-away side views of the seal assembly of FIG. 12 taken along a cut-line 15a-15a of FIG. 15a, showing the seal assembly in unflexed and flexed conditions, respectively .

[0040] FIG. 16 is a cut-away side view of the rotary earth bit of FIGS. Ia and Ib, which includes another embodiment of a seal assembly, in accordance with the invention.

[0041] FIGS. 17a and 17b are top and bottom exploded perspective views of the seal assembly of FIG. 16.

[0042] FIGS. 18a and 18b are top and bottom perspective views of the elastomeric sealing ring of FIGS. 4a and 4b and the rigid dynamic sealing ring of FIGS. 6a and 6b coupled together for use in the seal assembly of FIG. 16.

[0043] FIG. 19a is a close-up view of the seal assembly of FIG 16, in accordance with the invention.

[0044] FIGS. 19b and 19c are cut-away side views of the seal assembly of FIG. 16 taken along a cut-line 19a-19a of FIG. 19a, showing the seal assembly in unflexed and flexed conditions, respectively .

[0045] FIG. 20a is a flow diagram of a method, in accordance with the invention, of providing a seal for an earth bit. [0046] FIG. 20b is a flow diagram of another method, in accordance with the invention, of providing a seal for an earth bit. [0047] FIGS. 21a, 21b and 21c are flow diagrams of methods, in accordance with the invention, of manufacturing a seal assembly.

DETAILED DESCRIPTION OF THE INVENTION

[0048] The invention includes a seal assembly for use with an earth bit, such as a rotary earth bit. The rotary earth bit includes a lug and cutting cone, and the seal assembly is positioned to retain lubricant between the lug and cutting cone. Further, the seal assembly is positioned to restrict the flow of debris to a region between the lug and cutting cone.

[0049] In general, the seal assembly includes an elastomeric sealing ring which carries a rigid reinforcement ring. The rigid reinforcement ring reinforces the elastomeric sealing ring. However, it should be noted that the rigid reinforcement ring is an optional component, as discussed in more detail with FIG. 4a. Further, the seal assembly includes a rigid dynamic sealing ring. The rigid dynamic sealing ring reduces the likelihood that the elastomeric sealing ring will become impregnated with debris. The elastomeric sealing ring, rigid dynamic sealing ring and rigid reinforcement ring are statically sealed together. In some embodiments, the elastomeric sealing ring, rigid dynamic sealing ring and rigid reinforcement ring are statically sealed together so they operate as a single integral seal.

[0050] In accordance with the invention, the elastomeric sealing ring restricts the rotation of the rigid dynamic sealing ring relative to the rigid reinforcement ring. The elastomeric sealing ring restricts the rotation of the rigid dynamic sealing ring relative to the rigid reinforcement ring so that the relative rotation of the rigid dynamic sealing ring and rigid reinforcement ring is driven to zero. The elastomeric sealing ring restricts the rotation of the rigid dynamic sealing ring relative to the rigid reinforcement ring so that the rigid dynamic sealing ring and rigid reinforcement ring rotate together. The elastomeric sealing ring restricts the rotation of the rigid dynamic sealing ring relative to the rigid reinforcement ring so that the rigid dynamic sealing ring rotates in response to the rotation of the rigid reinforcement ring. The elastomeric sealing ring restricts the rotation of the rigid dynamic sealing ring relative to the rigid reinforcement ring so that the rigid dynamic sealing ring rotates in response to the rotation of the elastomeric sealing ring. Hence, the rigid dynamic sealing ring is more likely to rotate in response to the rotation of the elastomeric sealing ring and rigid reinforcement ring. In this way, the rigid dynamic sealing ring is less likely to lock. Further, the elastomeric sealing ring and rigid dynamic sealing ring are more likely to remain statically sealed together, and is less likely to be dynamically sealed together.

[0051] The elastomeric sealing ring typically forms a static seal with the cutting cone or lug. For example, in one embodiment, it is desirable for the elastomeric sealing ring to form a static seal with the cutting cone so that the elastomeric sealing ring and rigid reinforcement ring rotate in response to the rotation of the cutting cone. Further, in this embodiment, it is desirable for the rigid dynamic sealing ring to form a dynamic seal with the lug. The rigid dynamic sealing ring rotates in response to the rotation of the cutting cone because, as mentioned above, the elastomeric sealing ring restricts the rotation of the rigid dynamic sealing ring. In this way, the rigid dynamic sealing ring is more likely to form a dynamic seal with the lug and less likely to form a static seal with the lug. Hence, the rigid dynamic sealing ring is less likely to lock and undesirably form a static seal with the lug or a dynamic seal with the elastomeric sealing ring in response to mud packing.

[0052] In another embodiment, the elastomeric sealing ring forms a static seal with the lug so that the elastomeric sealing ring and rigid reinforcement ring do not rotate in response to the rotation of the cutting cone. Further, in this embodiment, it is desirable for the rigid dynamic sealing ring to form a dynamic seal with the cutting cone. The rigid dynamic sealing ring does not rotate in response to the rotation of the cutting cone because, as mentioned above, the elastomeric sealing ring restricts the rotation of the rigid dynamic sealing ring. In this way, the rigid dynamic sealing ring is more likely to form a dynamic seal with the cutting cone and less likely to form a static seal with the cutting cone. Hence, the rigid dynamic sealing ring is less likely to lock and undesirably form a static seal with the cutting cone, or a dynamic seal with the elastomeric sealing ring, in response to mud packing.

[0053] The elastomeric sealing ring can restrict the rotation of the rigid dynamic sealing ring relative to the rigid reinforcement ring in many different ways. In one embodiment, the elastomeric sealing ring includes an elastomeric sealing ring arm which extends between the elastomeric sealing ring and rigid dynamic sealing ring. The elastomeric sealing ring arm engages the rigid dynamic sealing ring so that the rotation of the rigid dynamic sealing ring relative to the rigid reinforcement ring is restricted. In another embodiment, a protrusion extends between the elastomeric sealing ring and rigid dynamic sealing ring, wherein the protrusion restricts the rotation of the rigid dynamic sealing ring relative to the rigid reinforcement ring. The protrusion can be carried by the elastomeric sealing ring arm. [0054] The elastomeric sealing ring biases the rigid dynamic sealing ring against the cutting cone or lug so that the dynamic seal formed by the rigid dynamic sealing ring is less likely to break. Further, the elastomeric sealing ring biases the rigid dynamic sealing ring against the cutting cone or lug so that the dynamic seal is less likely to break in response to the misalignment of the cutting cone and lug. For example, in some embodiments, the elastomeric sealing ring biases the rigid dynamic sealing ring against the lug so that the dynamic seal between the rigid dynamic sealing ring and lug is stronger and less likely to break. In other embodiments, the elastomeric sealing ring biases the rigid dynamic sealing ring against the cutting cone so that the dynamic seal between the rigid dynamic sealing ring and cutting cone is stronger and less likely to break. It is desirable to reduce the likelihood of the dynamic seal breaking to reduce the likelihood of debris entering and lubricant leaving the region between the lug and cutting cone. Hence, it is desirable to bias the rigid dynamic sealing ring against the lug or cutting cone. [0055] Another function of the elastomeric sealing ring is to operate as a diaphragm. The elastomeric sealing ring operates as a diaphragm when it includes an elastomeric sealing ring arm which separates a region external to the rotary earth bit from the region between the lug and cutting cone. Further, the elastomeric sealing ring operates as a diaphragm when the elastomeric sealing ring arm allows the rigid dynamic sealing ring to move relative to it. The elastomeric sealing ring allows the rigid dynamic sealing ring to move because the elastomeric sealing ring transmits, in an axial direction, an axial force to the rigid dynamic sealing ring. The rigid dynamic sealing ring moves relative to the elastomeric sealing ring so it can be biased against the lug or cutting cone, as described above.

[0056] FIG. Ia is a perspective view of a rotary earth bit 100, and FIG. Ib is a cut-away view of rotary earth bit 100 taken along a cut-line Ib-Ib of FIG. Ia. Rotary earth bit 100 is embodied as a tri-cone rotary earth bit and includes three lugs 101. However, only two lugs are shown in FIG. Ia. A cutting cone 102, having cutting cone teeth 103, is rotatably mounted to a journal segment 101a (FIG. Ib) of each lug 101. Cutting cone 102 and journal segment 101a bound an internal region 108, which is positioned between them. Rotary earth bit 100 can include one or more roller bearings 107a and/or ball bearings 107b positioned in internal region 108. Roller bearings 107a and ball bearings 107b facilitate the rotation of cutting cone 102 relative to lug 101. In particular, roller bearings 107a and ball bearings 107b facilitate the rotation of cutting cone 102 relative to journal segment 101a. In some embodiments, lug 101 and cutting cone 102 are coupled together with a journal bearing, such as the journal bearing disclosed in U.S. Patent Nos . 6,691,804 and 7,182,154. [0057] A seal assembly (not shown) is typically positioned in a seal region 104 to restrict the flow of lubricant from internal region 108 to an external region 109. The lubricant lubricates roller bearings 107a and ball bearings 107b to reduce the amount of friction between them and lug 101 and cutting cone 102. The seal assembly also restricts the flow of debris from external region 109 to internal region 108. In this way, the seal assembly restricts the flow of material through a debris entry region of rotary earth bit 100. It should be noted that it is desirable for the seal assembly to provide a seal between lug 101 and cutting cone 102 in response to cutting cone 102 moving in an axial direction 105 and radial direction 106 relative to lug 101. Cutting cone 102 can move in axial direction 105 and radial direction 106 in response to being undesirably misaligned with lug 101. Further, cutting cone 102 can move in axial direction 105 and radial direction 106 in response to engaging the formation.

[0058] In some embodiments, it is desirable for the seal assembly to rotate relative to lug 101 in response to the rotation of cutting cone 102. When the seal assembly rotates relative to lug 101, it is desirable for the seal assembly to form a dynamic seal with lug 101 and a static seal with cutting cone 102. In other embodiments, it is desirable for cutting cone 102 to rotate relative to the seal assembly. When cutting cone 102 rotates relative to the seal assembly, it is desirable for the seal assembly to form a dynamic seal with cutting cone 102 and a static seal with lug 101.

[0059] As mentioned above, the seal assembly generally includes an elastomeric sealing ring and rigid dynamic sealing ring, and can include a rigid reinforcement ring, if desired. The elastomeric sealing ring, rigid dynamic sealing ring and rigid reinforcement ring of the seal assembly can be of many different types, several of which will be discussed in more detail presently. [0060] FIGS. 2a and 2b are top and bottom perspective views, respectively, of one embodiment of an elastomeric sealing ring, denoted as elastomeric sealing ring 110a. A cut-away view of elastomeric sealing ring 110a, taken along a cut-line 2a-2a of FIG. 2a, is indicated by an indication arrow 150a. An alternative embodiment of elastomeric sealing ring 110a is indicated by an indication arrow 150b in FIG. 2a. In the embodiments of indication arrows 150a and 150b, elastomeric sealing ring 110a includes an elastomeric sealing ring body 111 which is annular in shape and has a central opening. Elastomeric sealing ring 110a includes a static sealing surface 118a and an opposed surface 118c. Elastomeric sealing ring 110a includes an outer surface 118b which extends along its outer periphery and between surfaces 118a and 118c. Outer surface 118b extends at a non-zero angle relative to surfaces 118a and 118c, wherein the non-zero angle is about 90° in this embodiment .

[0061] Elastomeric sealing ring 110a includes an elastomeric sealing ring groove 112. Elastomeric sealing ring groove 112 is sized and shaped to receive a rigid reinforcement ring, such as the rigid reinforcement ring discussed below with FIGS. 7a and 7b. In the embodiment of indication arrow 150a, elastomeric sealing ring groove 112 is positioned so it extends through surface 118c and, in the embodiment of indication arrow 150b, elastomeric sealing ring groove 112 is positioned so it extends through static sealing surface 118a. It should be noted that the positioning of groove 112 in the embodiments of indication arrows 150a and 150b can be used with many other embodiments of elastomeric sealing rings, such as sealing rings 110b and 110c, which are discussed in more detail below.

[0062] Elastomeric sealing ring 110a includes an elastomeric sealing ring arm 113 which extends along the inner periphery of elastomeric sealing ring body 111 and through the central opening. Elastomeric sealing ring arm 113 extends in a direction away from outer surface 118b. Further, elastomeric sealing ring arm 113 extends at a non-zero angle relative to groove 112, wherein the non-zero angle is 90° in this embodiment.

[0063] Elastomeric sealing ring 110a includes an elastomeric sealing ring protrusion 114 extending from elastomeric sealing ring arm 113 in a direction towards static sealing surface 118a. In this embodiment, elastomeric sealing ring protrusion 114 extends perpendicular to static sealing surface 118a and elastomeric sealing ring arm 113, and parallel to elastomeric sealing ring groove 112. In this embodiment, elastomeric sealing ring 110a includes five elastomeric sealing ring protrusions 114 carried by corresponding arms. However, it should be noted that elastomeric sealing rings 110a generally includes one or more elastomeric sealing ring protrusions 114. Elastomeric sealing ring protrusions 114 are sized and shaped to be received by a rigid dynamic sealing ring notch included with a rigid dynamic sealing ring, such as the rigid dynamic sealing ring discussed below with FIGS. 5a and 5b. [0064] In the embodiments of indication arrows 150a and 150b, elastomeric sealing ring protrusion 114 terminates between elastomeric sealing ring arm 113 and static sealing surface 118a. However, elastomeric sealing ring protrusion 114 terminates closer to elastomeric sealing ring arm 113 than static sealing surface 118a. An embodiment in which the elastomeric sealing ring protrusion terminates closer to static sealing surface 118a than elastomeric sealing ring arm 113 will be discussed in more detail presently.

[0065] FIGS. 3a and 3b are top and bottom perspective views, respectively, of another embodiment of an elastomeric sealing ring, denoted as elastomeric sealing ring 110b. A cut-away view of elastomeric sealing ring 110b, taken along a cut-line 3a-3a of FIG. 3a, is indicated by an indication arrow 151a. An alternative embodiment of elastomeric sealing ring 110b is indicated by an indication arrow 151b in FIG. 3a. In the embodiments of indication arrows 151a and 151b, elastomeric sealing ring 110b includes elastomeric sealing ring body 111 and elastomeric sealing ring groove 112 and elastomeric sealing ring arm 113. In the embodiment of indication arrow 151a, elastomeric sealing ring groove 112 is positioned so it extends through surface 118c and, in the embodiment of indication arrow 151b, elastomeric sealing ring groove 112 is positioned so it extends through surfaces 118b and 118c. It should be noted that the positioning of groove 112 in the embodiments of indication arrows 151a and 151b can be used with many other embodiments of elastomeric sealing rings, such as sealing rings 110a and 110c.

[0066] Elastomeric sealing ring 110b includes an elastomeric sealing ring protrusion 115 extending from elastomeric sealing ring arm 113 in the direction towards static sealing surface 118a. In the embodiments of indication arrows 151a and 151b, elastomeric sealing ring protrusion 115 terminates between elastomeric sealing ring arm 113 and static sealing surface 118a. However, in these embodiments, elastomeric sealing ring protrusion 115 terminates closer to static sealing surface 118a than elastomeric sealing ring arm 113. An embodiment in which the elastomeric sealing ring protrusion terminates closer to elastomeric sealing ring arm 113 than static sealing surface 118a was discussed in more detail above with FIGS. 2a and 2b.

[0067] FIGS. 4a and 4b are top and bottom perspective views, respectively, of one embodiment of an elastomeric sealing ring, denoted as elastomeric sealing ring 110c. A cut-away view of elastomeric sealing ring 110c, taken along a cut-line 4a-4a of FIG. 4a, is indicated by an indication arrow 152a. An alternative embodiment of elastomeric sealing ring 110c is shown in FIG. 4a and indicated by an indication arrow 152b. In the embodiments of indication arrows 152a and 152b, elastomeric sealing ring 110c includes elastomeric sealing ring body 111 and elastomeric sealing ring arm 113.

[0068] In the embodiment of indication arrow 152a, elastomeric sealing ring 110c includes elastomeric sealing ring groove 112 positioned so it extends through surface 118c and, in the embodiment of indication arrow 151b, elastomeric sealing ring body 111 does not include elastomeric sealing ring groove 112. It should be noted that the embodiments of indication arrows 152a and 152b can be used with many other embodiments of elastomeric sealing rings, such as sealing rings 110a and 110b.

[0069] Elastomeric sealing ring 110c does not include an elastomeric sealing ring protrusion, such as protrusions 114 and 115. Embodiments of elastomeric sealing rings including elastomeric sealing ring protrusions are discussed above with FIGS. 2a and 2b and FIGS. 3a and 3b. In the embodiments of FIG. 4a, elastomeric sealing ring arm 113 is sized and shaped to be received by a rigid dynamic sealing ring groove of a rigid dynamic sealing ring, such as the rigid dynamic sealing ring discussed below with FIGS. 6a and 6b. Several embodiments of rigid dynamic sealing rings will be discussed in more detail presently.

[0070] FIGS. 5a and 5b are top and bottom perspective views, respectively, of one embodiment of a rigid dynamic sealing ring, denoted as rigid dynamic sealing ring 120a. A cut-away view of rigid dynamic sealing ring 120a taken along a cut-line 5a-5a of FIG. 5a is indicated by an indication arrow 153. In this embodiment, rigid dynamic sealing ring 120a includes a rigid dynamic sealing ring body 121a having a rigid dynamic sealing ring notch 123. Rigid dynamic sealing ring body 121a is annular in shape with a central opening, and rigid dynamic sealing ring notch 123 extends along the outer diameter of rigid dynamic sealing ring body 121a. Rigid dynamic sealing ring notch 123 faces away from the central opening of rigid dynamic sealing ring body 121a and a dynamic sealing surface 117a, and extends through a surface 117b. It should be noted that surfaces 117a and 117b are opposed surfaces of rigid dynamic sealing ring body 121a. [0071] Dynamic sealing surface 117a can have many different shapes. For example, dynamic sealing surface 117a can be flat or curved. Dynamic sealing surface 117a can be curved in many different ways. For example, dynamic sealing surface 117a can have a convex or concave curvature. In some embodiments, dynamic sealing surface 117a includes grooves which extend through it, so that surface 117a is a grooved surface.

[0072] In this embodiment, rigid dynamic sealing ring 120a includes five elastomeric sealing ring notches 123 for illustrative purposes. However, it should be noted that rigid dynamic sealing ring 120a generally includes one or more rigid dynamic sealing ring notches 123. In some embodiments, the number of rigid dynamic sealing ring notches 123 is the same as the number of elastomeric sealing ring protrusions included with the elastomeric sealing ring. In other embodiments, the number of rigid dynamic sealing ring notches 123 is different from the number of elastomeric sealing ring protrusions included with the elastomeric sealing ring. Rigid dynamic sealing ring notches 123 are sized and shaped to receive an elastomeric sealing ring protrusion included with an elastomeric sealing ring, such as the elastomeric sealing rings discussed above with FIGS. 2a and 2b and FIGS. 3a and 3b. [0073] FIGS. 6a and 6b are top and bottom perspective views, respectively, of another embodiment of a rigid dynamic sealing ring, denoted as rigid dynamic sealing ring 120b. A cut-away view of rigid dynamic sealing ring 120b taken along a cut-line 6a-6a of FIG. 6a is indicated by an indication arrow 154. In this embodiment, rigid dynamic sealing ring 120b includes a rigid dynamic sealing ring body 121b having rigid dynamic sealing ring grooves 122 and 124. Rigid dynamic sealing ring body 121b is annular in shape with a central opening, and rigid dynamic sealing ring groove 124 extends along the outer diameter of rigid dynamic sealing ring body 121b and faces away from the central opening. Further, rigid dynamic sealing ring groove 122 faces away from dynamic sealing surface 117a, and extends through surface 117b. [0074] It should be noted that rigid dynamic sealing rings 120a and 120b can include many different types of rigid materials, such as metals or metal alloys, ceramics, carbides and thermoplastics, among others. For example, in some embodiments, rigid dynamic sealing ring 120a and 120b include metal, such as steel. In some embodiments, rigid dynamic sealing rings 120a and 120b include a copper beryllium alloy. In general, rigid dynamic sealing rings 120a and 120b include a material that is wear resistant. Further, rigid dynamic sealing rings 120a and 120b include a material that can be bonded to the material of the elastomeric sealing ring. [0075] FIGS. 7a and 7b are top and bottom perspective views, respectively, of one embodiment of a rigid reinforcement ring, denoted as rigid reinforcement ring 125. In this embodiment, rigid reinforcement ring 125 includes a rigid reinforcement ring body 126, which is annular in shape with a central opening. Rigid reinforcement ring body 126 is sized and shaped to be received by elastomeric sealing ring groove 112. It should be noted that rigid reinforcement ring can include many different types of rigid materials, such as the materials discussed above that can be included in rigid dynamic sealing rings 120a and 120b. In some embodiments, rigid reinforcement ring 125 includes the same material as rigid dynamic sealing rings 120a and 120b. In other embodiments, rigid reinforcement ring 125 includes a material different from the material included in rigid dynamic sealing rings 120a and 120b. In this way, the material included in rigid reinforcement ring 125 can be chosen to provide the elastomeric sealing ring with a desired amount of reinforcement. In general, as the material included in rigid reinforcement ring 125 increases in hardness, the elastomeric sealing ring is stiffer and is provided with a greater amount of reinforcement. Further, as the material included in rigid reinforcement ring 125 decreases in hardness, the elastomeric sealing ring is more flexible and is provided with a lesser amount of reinforcement.

[0076] FIG. 8 is a cut-away side view of rotary earth bit 100, which includes a seal assembly 130a, in accordance with the invention. FIGS. 9a and 9b are top and bottom exploded perspective views of seal assembly 130a. Seal assembly 130a is positioned within seal region 104 to retain lubricant between lug 101 and cutting cone 102. Further, seal assembly 130a is positioned within seal region 104 to restrict the flow of debris to internal region 108 between lug 101 and cutting cone 102. [0077] In this embodiment, seal assembly 130a includes elastomeric sealing ring 110a (FIGS. 2a and 2b) which carries rigid reinforcement ring 125 (FIGS. 7a and 7b) . Rigid reinforcement ring 125 reinforces elastomeric sealing ring 110a. Further, seal assembly 130a includes rigid dynamic sealing ring 120a (FIGS. 5a and 5b) . Rigid dynamic sealing ring 120a reduces the likelihood that elastomeric sealing ring 110a will become impregnated with debris. Elastomeric sealing ring 110a, rigid dynamic sealing ring 120a and rigid reinforcement ring 125 are statically sealed together. In particular, elastomeric sealing ring 110a, rigid dynamic sealing ring 120a and rigid reinforcement ring 125 are statically sealed together so they operate as a single integral seal .

[0078] FIGS. 10a and 10b are top and bottom perspective views of elastomeric sealing ring 110a, rigid dynamic sealing ring 120a and rigid reinforcement ring 125 statically sealed together. Rigid reinforcement ring 125 is received by elastomeric sealing ring groove 112, as shown in FIG. 10b, so that rigid dynamic sealing ring 120a and rigid reinforcement ring 125 are coupled together by elastomeric sealing ring 110a. In this embodiment, elastomeric sealing ring groove 112 receives rigid reinforcement ring 125 so that rigid reinforcement ring 125 does not form a static or dynamic seal with lug 101 or cutting cone 102. In other embodiments of sealing ring 110a, such as those which utilize groove 112 embodied as indicated by indication arrow 151b (FIG. 3a), rigid reinforcement ring 125 forms a static seal with lug 101 or cutting cone 102. Rigid reinforcement ring 125 forms a static seal with lug 101 when it is received by groove 112 embodied as indicated by indication arrow 151b, and elastomeric sealing ring 110a is oriented as indicated by an indication arrow 155 in FIG. 8. Elastomeric sealing ring 110a and rigid reinforcement ring 125 can be statically sealed together in many different ways. In this embodiment, elastomeric sealing ring 110a and rigid reinforcement ring 125 are bonded together. Elastomeric sealing ring 110a and rigid reinforcement ring 125 can be bonded together in many different ways, such as by using an adhesive. [0079] In general, elastomeric sealing ring 110a forms a static seal with lug 101 or cutting cone 102. For example, in this embodiment, it is desirable for elastomeric sealing ring 110a to form a static seal with cutting cone 102 so that elastomeric sealing ring 110a and rigid reinforcement ring 125 rotate in response to the rotation of cutting cone 102. Further, in this embodiment, it is desirable for rigid dynamic sealing ring 120a to form a dynamic seal with lug 101. Rigid dynamic sealing ring rotates in response to the rotation of cutting cone 102 because, as discussed in more detail below, elastomeric sealing ring 110a restricts the rotation of rigid dynamic sealing ring 120a. In this way, rigid dynamic sealing ring 120a is more likely to form a dynamic seal with lug 101 and less likely to form a static seal with lug 101. Hence, rigid dynamic sealing ring 120a is less likely to lock and undesirably form a static seal with lug 101 in response to mud packing.

[0080] It should be noted that, in this embodiment, dynamic sealing surface 117a is between seal assembly 130a and lug 101, and static sealing surfaces 118a and 118b are between seal assembly 130a and cutting cone 102. In this way, seal assembly 130a forms a dynamic seal with lug 101 and a static seal with cutting cone 102. In particular, elastomeric sealing ring 110a frictionally engages cutting cone 102 so elastomeric sealing ring 110a will rotate with cutting cone 102. Further, elastomeric sealing ring 110a frictionally engages cutting cone 102 so a static seal is formed between them. Elastomeric sealing ring 110a forms a static seal with cutting cone 102 to reduce the likelihood of lubricant leaving and debris entering internal region 108. In the alternative embodiment indicated by indication arrow 150b in FIG. 2a, rigid reinforcement ring 125 faces static sealing surface 118a and forms a static seal with cutting cone 102. In this way, rigid reinforcement ring 125 forms an interference fit with cutting cone 102.

[0081] In another embodiment, such as the embodiment indicated by indication arrow 155 of FIG. 8, elastomeric sealing ring 110a forms a static seal with lug 101 so that elastomeric sealing ring 110a and rigid reinforcement ring 125 do not rotate in response to the rotation of cutting cone 102. Further, in the embodiment of indication arrow 155, it is desirable for rigid dynamic sealing ring 120a to form a dynamic seal with cutting cone 102. Rigid dynamic sealing ring 120a does not rotate in response to the rotation of cutting cone 102 because, as discussed in more detail below, elastomeric sealing ring 110a restricts the rotation of rigid dynamic sealing ring 120a. In this way, rigid dynamic sealing ring 120a is more likely to form a dynamic seal with cutting cone 102 and is less likely to form a static seal with cutting cone 102. Hence, rigid dynamic sealing ring 120a is less likely to lock and undesirably form a static seal with cutting cone 102 in response to mud packing. It should be noted that any of the embodiments of elastomeric sealing rings, such as those indicated by indication arrows 150a, 150b, 151a, 151b, 152a and 152b, can be positioned in region 104 as indicated by indication arrow 155. [0082] It should also be noted that, in the embodiment indicated by indication arrow 155, static sealing surfaces 118a and 118b are between seal assembly 130a and lug 101, and dynamic sealing surface 117a is between seal assembly 130a and cutting cone 102. In this way, in the embodiment indicated by indication arrow 155, seal assembly 130a forms a static seal with lug 101 and a dynamic seal with cutting cone 102. In particular, elastomeric sealing ring 110a frictionally engages lug 101 so elastomeric sealing ring 110a will not rotate with cutting cone 102. Further, elastomeric sealing ring 110a frictionally engages lug 101 so a static seal is formed between them. Elastomeric sealing ring 110a forms a static seal with lug 101 to reduce the likelihood of lubricant leaving and debris entering internal region 108. [0083] In accordance with the invention, elastomeric sealing ring 110a restricts the rotation of rigid dynamic sealing ring 120a. For example, in the embodiments of sealing rings which do not include a reinforcement ring, such as the embodiment indicated by indication arrow 152b of FIG. 4a, elastomeric sealing ring 110a restricts the rotation of rigid dynamic sealing ring 120a relative to elastomeric sealing ring body 111. In the embodiments which include a rigid reinforcement ring, elastomeric sealing ring 110a restricts the rotation of rigid dynamic sealing ring 120a relative to the rigid reinforcement ring 125 and elastomeric sealing ring body 111. Elastomeric sealing ring 110a restricts the rotation of rigid dynamic sealing ring 120a so that their relative rotation is driven to zero. Elastomeric sealing ring 110a restricts the rotation of rigid dynamic sealing ring 120a so that rigid dynamic sealing ring 120a and rigid reinforcement ring 125 rotate together. Elastomeric sealing ring 110a restricts the rotation of rigid dynamic sealing ring 120a so that rigid dynamic sealing ring 120a and elastomeric sealing ring body 111 rotate together. In some embodiments, elastomeric sealing ring 110a restricts the rotation of rigid dynamic sealing ring 120a relative to rigid reinforcement ring 125 so that rigid dynamic sealing ring 120a rotates in response to the rotation of rigid reinforcement ring 125. Hence, rigid dynamic sealing ring 120a is more likely to rotate in response to the rotation of elastomeric sealing ring body 111 and rigid reinforcement ring 125. In this way, elastomeric sealing ring 110a and rigid dynamic sealing ring 120a are more likely to remain statically sealed together, and are less likely to be dynamically sealed together. Elastomeric sealing ring 110a can restrict the rotation of rigid dynamic sealing ring 120a in many different ways, one of which will be discussed in more detail presently.

[0084] FIG. 11a is a close-up view of seal assembly 130a showing elastomeric sealing ring protrusions 114 being received by a corresponding rigid dynamic sealing ring notch 123 to form a joint 116. FIGS, lib and lie are cut-away side views of seal assembly 130a taken along a cut-line lla-lla of FIG. 11a showing elastomeric sealing ring protrusions 114 being received by a corresponding rigid dynamic sealing ring notch 123 to form joint 116. It should be noted that elastomeric sealing ring arm 113 is shown in unflexed and flexed conditions, respectively, in FIGS, lib and lie. One way in which elastomeric sealing ring 110a restricts the rotation of rigid dynamic sealing ring 120a relative to rigid reinforcement ring 125 is by engaging elastomeric sealing ring 110a and rigid dynamic sealing ring 120a together with a joint, wherein the joint includes a protrusion and notch.

[0085] It should be noted that, in this embodiment, elastomeric sealing ring arm 113 and elastomeric sealing ring protrusion 114 are spaced from lug 101 by rigid dynamic sealing ring 120a. Hence, rigid dynamic sealing ring 120a is positioned between dynamic sealing surface 117a and elastomeric sealing ring 110a. In this way, rigid dynamic sealing ring 120a reduces the likelihood that elastomeric sealing ring 110a will become impregnated with debris. In some embodiments, protrusion 114 terminates flush with surface 117b and, in other embodiments, protrusion 114 terminates proximate with surface 117b. When protrusion 114 terminates proximate with 117b, it typically terminates within about two to three millimeters therefrom. Hence, in some embodiments, protrusion 114 terminates less than about two to three millimeters before surface 117b, and, in other embodiments, protrusion 114 terminates less than about two to three millimeters after surface 117b. When protrusion 114 terminates before surface 117b, it terminates between arm 113 and surface 117b. Further, when protrusion 114 terminates after surface 117b, it terminates between surfaces 117b and 118a. In general, elastomeric sealing ring arm 113 is allowed to flex more in response to protrusion 114 terminating closer to elastomeric sealing ring arm 113. Further, elastomeric sealing ring arm 113 is allowed to flex less in response to protrusion 114 terminating further away from elastomeric sealing ring arm 113. Hence, the amount that elastomeric sealing ring arm 113 is allowed to flex can be controlled in response to controlling where protrusion 114 terminates .

[0086] In this embodiment, elastomeric sealing ring 110a includes five elastomeric sealing ring protrusions 114 and rigid dynamic sealing ring 120a includes five rigid dynamic sealing ring notches 123. Hence, in this embodiment, seal assembly 130a includes five joints 116. It should be noted, however, that seal assembly 130a generally includes one or more joints. Elastomeric sealing ring protrusions 114 are positioned to receive a corresponding rigid dynamic sealing ring notch 123 when elastomeric sealing ring 110a and rigid dynamic sealing ring 120a are engaged together. In this way, elastomeric sealing ring 110a and rigid dynamic sealing ring 120a are engaged together with a joint. [0087] Elastomeric sealing ring protrusion 114 and rigid dynamic sealing ring notch 123 can be formed in many different ways. In some embodiments, protrusion 114 and notch 123 are formed before elastomeric sealing ring 110a is engaged with rigid dynamic ring 120a. In other embodiments, notch 123 is used as a mold to form protrusion 114 by flowing elastomeric material into notch 123 and letting it set. In some embodiments, protrusion 114 and notch 123 are formed in elastomeric sealing ring 110a and rigid dynamic sealing ring 120a, respectively. In other embodiments, protrusion 114 and notch 123 are formed in rigid dynamic sealing ring 120a and elastomeric sealing ring 110a, respectively.

[0088] As mentioned above, when elastomeric sealing ring 110a and rigid dynamic sealing ring 120a are engaged together, their rotation relative to each other is restricted. The rotation of elastomeric sealing ring 110a and rigid dynamic sealing ring 120a relative to each other is restricted because elastomeric sealing ring protrusion 114 engages a portion of rigid dynamic sealing ring body 121a (FIG. lla) that bounds rigid dynamic sealing ring notch 123. Further, as mentioned above, elastomeric sealing ring 110a will rotate with cutting cone 102 because they are frictionally engaged together. Hence, rigid dynamic sealing ring 120a will rotate in response to the rotation of cutting cone 102 because elastomeric sealing ring 110a and rigid dynamic sealing ring 120a are engaged together with joint 116. In this way, rigid dynamic sealing ring 120a is less likely to lock and undesirably form a static seal with lug 101 in response to mud packing.

[0089] In the embodiment indicated by indication arrow 155 of FIG. 8, elastomeric sealing ring 110a will not rotate with cutting cone 102 because elastomeric sealing ring 110a is frictionally engaged with lug 101. Hence, rigid dynamic sealing ring 120a will not rotate in response to the rotation of cutting cone 102 because elastomeric sealing ring 110a and rigid dynamic sealing ring 120a are engaged together with joint 116. In this way, rigid dynamic sealing ring 120a is less likely to lock and undesirably form a static seal with cutting cone 102 in response to mud packing. [0090] Elastomeric sealing ring 110a provides many different functions. For example, one function of elastomeric sealing ring 110a is to operate as a diaphragm. Elastomeric sealing ring 110a operates as a diaphragm because elastomeric sealing ring arm 113 separates internal region 108 and external region 109 (FIGS. Ib and 8) . Further, elastomeric sealing ring 110a operates as a diaphragm because, as described below, elastomeric sealing ring arm 113 allows rigid dynamic sealing ring 120a to move relative to elastomeric sealing ring body 111.

[0091] Elastomeric sealing ring 110a functions to bias rigid dynamic sealing ring 120a against lug 101 (FIG. 8) or cutting cone 102 (FIG. 8, indication arrow 155), so that the dynamic seal formed by rigid dynamic sealing ring 120a is less likely to break. Further, elastomeric sealing ring 110a biases rigid dynamic sealing ring 120a against lug 101 or cutting cone 102 so that the dynamic seal is less likely to break in response to the misalignment of lug 101 and cutting cone 102. For example, in some embodiments, elastomeric sealing ring 110a biases rigid dynamic sealing ring 120a against lug 101 so that the dynamic seal between rigid dynamic sealing ring 120a and lug 101 is stronger and less likely to break. In the embodiment indicated by indication arrow 155, elastomeric sealing ring 110a biases rigid dynamic sealing ring 120a against cutting cone 102 so that the dynamic seal between rigid dynamic sealing ring 120a and cutting cone 102 is stronger and less likely to break. It is desirable to reduce the likelihood of the dynamic seal breaking to reduce the likelihood of debris entering and lubricant leaving region 108. Hence, it is desirable to bias rigid dynamic sealing ring 120a against lug 101 or cutting cone 102. [0092] Elastomeric sealing ring 110a can bias rigid dynamic sealing ring 120a against lug 101 or cutting cone 102 in many different ways. In this embodiment, elastomeric sealing ring 110a biases rigid dynamic sealing ring 120a against lug 101 or cutting cone 102 because elastomeric sealing ring 110a transmits, in axial direction 105 (FIG. Ib) , an axial force to rigid dynamic sealing ring 120a. The axial force allows elastomeric sealing ring 110a to repeatably move between unflexed and flexed conditions, as shown in FIGS, lib and lie, respectively. Elastomeric sealing ring 110a can move between unflexed and flexed conditions because elastomeric sealing ring arm 113 can move between unflexed and flexed conditions .

[0093] In general, elastomeric sealing ring arm 113 is in the unflexed condition in response to rigid dynamic sealing ring 120a being disengaged from lug 101 (FIG. 8) and cutting cone 102 (FIG. 8, indication arrow 155) . Elastomeric sealing ring arm 113 is in the flexed condition in response to rigid dynamic sealing ring 120a engaging lug 101 (FIG. 8) or cutting cone 102 (FIG. 8, indication arrow 155) . In this embodiment, when elastomeric sealing ring arm 113 moves from the unflexed condition to the flexed condition, surface 117a, sealing ring 120a and protrusion 114 move toward surface 118a. Further, when elastomeric sealing ring arm 113 moves from the flexed condition to the unflexed condition, surface 117a, sealing ring 120a and protrusion 114 move away from surface 118a. In this way, elastomeric sealing ring 110a moves between unflexed and flexed conditions, and biases rigid dynamic sealing ring 120a against lug 101 or cutting cone 102. It should be noted that elastomeric sealing ring arm 113 remains in the unflexed condition until positioned in region 104 (FIG. Ib) . Elastomeric sealing ring arm 113 moves from the unflexed condition to the flexed condition in response to cutting cone 102 being coupled with lug 101. Further, sealing ring 120a is biased in response to cutting cone 102 being coupled with lug 101 so a dynamic seal is formed. The dynamic seal is typically formed between sealing ring 120a and lug 101, or between sealing ring 120a and cutting cone 102. [0094] It should be noted that rigid dynamic sealing ring 120a moves relative to rigid reinforcement ring 125 and elastomeric sealing ring body 111 in response to elastomeric sealing ring arm 113 moving between unflexed and flexed conditions. Elastomeric sealing ring 110a allows rigid dynamic sealing ring 120a to move because elastomeric sealing ring 110a transmits, in axial direction 105 (FIG. Ib), an axial force to rigid dynamic sealing ring 120a. Rigid dynamic sealing ring 120a moves relative to elastomeric sealing ring 110a so it can be biased against lug 101 or cutting cone 102, as described above. In general, rigid dynamic sealing ring 120a moves in axial direction 105.

[0095] In the embodiment of FIG. 8, elastomeric sealing ring arm 113 allows rigid dynamic sealing ring 120a to be biased against lug 101. In general, rigid dynamic sealing ring 120a is biased more against lug 101 in response to increasing the stiffness of elastomeric sealing ring arm 113. The stiffness of elastomeric sealing ring arm 113 can be increased and decreased in many different ways, such as by choosing its dimensions, as well as the stiffness of the material included therein. In general, the stiffness of ring arm 113 increases and decreases as its dimensions increase and decrease, respectively. Further, the stiffness of ring arm 113 increases and decreases as the stiffness of the material included therein increases and decreases, respectively. [0096] Rigid dynamic sealing ring 120a is forced more against lug 101 in response to the stiffness of elastomeric sealing ring arm 113 being increased. When rigid dynamic sealing ring 120a is biased more against lug 101, rigid dynamic sealing ring 120a engages lug 101 to form a stronger dynamic seal between them. Further, rigid dynamic sealing ring 120a is biased less against lug 101 in response to decreasing the stiffness of elastomeric sealing ring arm 113. Rigid dynamic sealing ring 120a is forced less against lug 101 in response to the stiffness of elastomeric sealing ring arm 113 being decreased. When rigid dynamic sealing ring 120a is biased less against lug 101, rigid dynamic sealing ring 120a forms a weaker dynamic seal with lug 101. It is generally desirable to form a stronger dynamic seal between lug 101 and rigid dynamic sealing ring 120a to reduce the likelihood of the dynamic seal breaking and to reduce the likelihood of debris entering and lubricant leaving region 108. It should be noted that the amount of bias applied by elastomeric sealing ring 110a to rigid dynamic sealing ring 120a can be increased because, as mentioned above, rigid dynamic sealing ring 120a is less likely to lock with lug 101 because it is engaged with elastomeric sealing ring 110a. [0097] In the embodiment indicated by indication arrow 155 of FIG. 8, elastomeric sealing ring arm 113 allows rigid dynamic sealing ring 120a to be biased against cutting cone 102. In general, rigid dynamic sealing ring 120a is biased more against cutting cone 102 in response to increasing the stiffness of elastomeric sealing ring arm 113. Rigid dynamic sealing ring 120a is forced more against cutting cone 102 in response to the stiffness of elastomeric sealing ring arm 113 being increased. When rigid dynamic sealing ring 120a is biased more against cutting cone 102, rigid dynamic sealing ring 120a engages cutting cone 102 to form a stronger dynamic seal between them. Further, rigid dynamic sealing ring 120a is biased less against cutting cone 102 in response to decreasing the stiffness of elastomeric sealing ring arm 113. Rigid dynamic sealing ring 120a is forced less against cutting cone 102 in response to the stiffness of elastomeric sealing ring arm 113 being decreased. When rigid dynamic sealing ring 120a is biased less against cutting cone 102, rigid dynamic sealing ring 120a forms a weaker dynamic seal with cutting cone 102.

[0098] FIG. 12 is a cut-away side view of rotary earth bit 100, which includes a seal assembly 130b, in accordance with the invention. FIGS. 13a and 13b are top and bottom exploded perspective views of seal assembly 130b. Seal assembly 130b is positioned within seal region 104 to retain lubricant between lug 101 and cutting cone 102. Further, seal assembly 130b is positioned within seal region 104 to restrict the flow of debris to internal region 108 between lug 101 and cutting cone 102. [0099] In this embodiment, seal assembly 130b includes elastomeric sealing ring 110b (FIGS. 3a and 3b) which carries rigid reinforcement ring 125 (FIGS. 7a and 7b) . Rigid reinforcement ring 125 reinforces elastomeric sealing ring 110b. Further, seal assembly 130b includes rigid dynamic sealing ring 120a (FIGS. 5a and 5b) . Rigid dynamic sealing ring 120a reduces the likelihood that elastomeric sealing ring 110b will become impregnated with debris. Elastomeric sealing ring 110b, rigid dynamic sealing ring 120a and rigid reinforcement ring 125 are statically sealed together. In particular, elastomeric sealing ring 110b, rigid dynamic sealing ring 120a and rigid reinforcement ring 125 are statically sealed together so they operate as a single integral seal .

[0100] FIGS. 14a and 14b are top and bottom perspective views of elastomeric sealing ring 110b, rigid dynamic sealing ring 120a and rigid reinforcement ring 125 statically sealed together. Rigid reinforcement ring 125 is received by elastomeric sealing ring groove 112, as shown in FIG. 14b, so that rigid dynamic sealing ring 120a and rigid reinforcement ring 125 are coupled together by elastomeric sealing ring 110b. In this embodiment, elastomeric sealing ring groove 112 receives rigid reinforcement ring 125 so that rigid reinforcement ring 125 does not form a static or dynamic seal with lug 101 or cutting cone 102. In other embodiments of sealing ring 110b, such as those which utilize groove 112 embodied as indicated by indication arrow 151b (FIG. 3a) , rigid reinforcement ring 125 can form a static seal with lug 101 or cutting cone 102. Rigid reinforcement ring 125 can form a static seal with lug 101 when it is received by groove 112 embodied as indicated by indication arrow 151b, and elastomeric sealing ring 110b is oriented as indicated by an indication arrow 156 in FIG. 12. Elastomeric sealing ring 110b and rigid reinforcement ring 125 can be statically sealed together in many different ways, such as by using an adhesive to bond them together.

[0101] In general, elastomeric sealing ring 110b forms a static seal with lug 101 or cutting cone 102. For example, in this embodiment, it is desirable for elastomeric sealing ring 110b to form a static seal with cutting cone 102 so that elastomeric sealing ring 110b and rigid reinforcement ring 125 rotate in response to the rotation of cutting cone 102. Further, in this embodiment, it is desirable for rigid dynamic sealing ring 120a to form a dynamic seal with lug 101. Rigid dynamic sealing ring rotates in response to the rotation of cutting cone 102 because, as discussed in more detail below, elastomeric sealing ring 110b restricts the rotation of rigid dynamic sealing ring 120a. In this way, rigid dynamic sealing ring 120a is more likely to form a dynamic seal with lug 101 and less likely to form a static seal with lug 101. Hence, rigid dynamic sealing ring 120a is less likely to lock and undesirably form a static seal with lug 101 in response to mud packing.

[0102] It should be noted that, in this embodiment, dynamic sealing surface 117a is between seal assembly 130b and lug 101, and static sealing surfaces 118a and 118b are between seal assembly 130b and cutting cone 102. In this way, seal assembly 130b forms a dynamic seal with lug 101 and a static seal with cutting cone 102. In particular, elastomeric sealing ring 110b frictionally engages cutting cone 102 so elastomeric sealing ring 110b will rotate with cutting cone 102. Further, elastomeric sealing ring 110b frictionally engages cutting cone 102 so a static seal is formed between them. Elastomeric sealing ring 110b forms a static seal with cutting cone 102 to reduce the likelihood of lubricant leaving and debris entering internal region 108. In the alternative embodiment indicated by indication arrow 150b in FIG. 2a, rigid reinforcement ring 125 faces static sealing surface 118a and forms a static seal with cutting cone 102. In this way, rigid reinforcement ring 125 forms an interference fit with cutting cone 102.

[0103] In another embodiment, such as the embodiment indicated by an indication arrow 156 of FIG. 12, elastomeric sealing ring 110b forms a static seal with lug 101 so that elastomeric sealing ring 110b and rigid reinforcement ring 125 do not rotate in response to the rotation of cutting cone 102. Further, in this embodiment, it is desirable for rigid dynamic sealing ring 120a to form a dynamic seal with cutting cone 102. Rigid dynamic sealing ring 120a does not rotate in response to the rotation of cutting cone 102 because, as discussed in more detail below, elastomeric sealing ring 110b restricts the rotation of rigid dynamic sealing ring 120a. In this way, rigid dynamic sealing ring 120a is more likely to form a dynamic seal with cutting cone 102 and is less likely to form a static seal with cutting cone 102. Hence, rigid dynamic sealing ring 120a is less likely to lock and undesirably form a static seal with cutting cone 102 in response to mud packing. It should be noted that the alternative embodiment indicated by indication arrow 150b in FIG. 2a can be combined with the embodiment of indication arrow 156 so that rigid reinforcement ring 125 faces static sealing surface 118a and forms a static seal with lug 102. In this way, rigid reinforcement ring 125 forms an interference fit with lug 102.

[0104] It should also be noted that, in the embodiment indicated by indication arrow 156, static sealing surfaces 118a and 118b are between seal assembly 130b and lug 101, and dynamic sealing surface 117a is between seal assembly 130b and cutting cone 102. In this way, in the embodiment indicated by indication arrow 156, seal assembly 130b forms a static seal with lug 101 and a dynamic seal with cutting cone 102. In particular, elastomeric sealing ring 110b frictionally engages lug 101 so elastomeric sealing ring 110b will not rotate with cutting cone 102. Further, elastomeric sealing ring 110b frictionally engages lug 101 so a static seal is formed between them. Elastomeric sealing ring 110b forms a static seal with lug 101 to reduce the likelihood of lubricant leaving and debris entering internal region 108. [0105] In accordance with the invention, elastomeric sealing ring 110b restricts the rotation of rigid dynamic sealing ring 120a. For example, in the embodiments of sealing rings which do not include a reinforcement ring, such as the embodiment indicated by indication arrow 152b of FIG. 4a, elastomeric sealing ring 110b restricts the rotation of rigid dynamic sealing ring 120a relative to elastomeric sealing ring body 111. In the embodiments which include a rigid reinforcement ring, elastomeric sealing ring 110b restricts the rotation of rigid dynamic sealing ring 120a relative to the rigid reinforcement ring. Elastomeric sealing ring 110b restricts the rotation of rigid dynamic sealing ring 120a so that their relative rotation is driven to zero. Elastomeric sealing ring 110b restricts the rotation of rigid dynamic sealing ring 120a relative to rigid reinforcement ring 125 so that rigid dynamic sealing ring 120a and rigid reinforcement ring 125 rotate together. [0106] In some embodiments, elastomeric sealing ring 110b restricts the rotation of rigid dynamic sealing ring 120a relative to rigid reinforcement ring 125 so that rigid dynamic sealing ring 120a rotates in response to the rotation of rigid reinforcement ring 125. Hence, rigid dynamic sealing ring 120a is more likely to rotate in response to the rotation of elastomeric sealing ring 110b and rigid reinforcement ring 125. In this way, elastomeric sealing ring 110b and rigid dynamic sealing ring 120a are more likely to remain statically sealed together, and less likely to be dynamically sealed together. Elastomeric sealing ring 110b can restrict the rotation of rigid dynamic sealing ring 120a relative to rigid reinforcement ring 125 in many different ways, one of which will be discussed in more detail presently.

[0107] FIG. 15a is a close-up view of seal assembly 130b showing elastomeric sealing ring protrusions 115 being received by a corresponding rigid dynamic sealing ring notch 123 to form joint 116. FIGS. 15b and 15c are cut-away side views of seal assembly 130b taken along a cut-line 15a-15a of FIG. 15a showing elastomeric sealing ring protrusions 115 being received by a corresponding rigid dynamic sealing ring notch 123 to form joint 116. It should be noted that elastomeric sealing ring arm 113 is shown in unflexed and flexed conditions, respectively, in FIGS. 15b and 15c. One way in which elastomeric sealing ring 110b restricts the rotation of rigid dynamic sealing ring 120a relative to rigid reinforcement ring 125 is by engaging elastomeric sealing ring 110b and rigid dynamic sealing ring 120a together with a joint, wherein the joint includes a protrusion and notch.

[0108] It should be noted that, in this embodiment, elastomeric sealing ring arm 113 and elastomeric sealing ring protrusion 115 are spaced from lug 101 by rigid dynamic sealing ring 120a. Hence, rigid dynamic sealing ring 120a is positioned between dynamic sealing surface 117a and elastomeric sealing ring 110b. In this way, rigid dynamic sealing ring 120a reduces the likelihood that elastomeric sealing ring 110b will become impregnated with debris. In this embodiment, elastomeric sealing ring protrusion 115 terminates after surface 117b. In this way, elastomeric sealing ring protrusion 115 terminates between surfaces 117b and 118a. [0109] In general, elastomeric sealing ring arm 113 is allowed to flex more in response to protrusion 115 terminating closer to elastomeric sealing ring arm 113. Further, elastomeric sealing ring arm 113 is allowed to flex less in response to protrusion 115 terminating further away from elastomeric sealing ring arm 113. Hence, the amount that elastomeric sealing ring arm 113 is allowed to flex can be controlled in response to controlling where protrusion 115 terminates.

[0110] In this embodiment, elastomeric sealing ring 110b includes five elastomeric sealing ring protrusions 115 and rigid dynamic sealing ring 120a includes five rigid dynamic sealing ring notches 123. Hence, in this embodiment, seal assembly 130b includes five joints 116. It should be noted, however, that seal assembly 130b generally includes one or more joints. Elastomeric sealing ring protrusions 115 are positioned to receive a corresponding rigid dynamic sealing ring notch 123 when elastomeric sealing ring 110b and rigid dynamic sealing ring 120a are engaged together. In this way, elastomeric sealing ring 110b and rigid dynamic sealing ring 120a are engaged together with a joint. [0111] Elastomeric sealing ring protrusion 115 and rigid dynamic sealing ring notch 123 can be formed in many different ways, such as those discussed in more detail above with protrusion 114. In some embodiments, protrusion 115 and notch 123 are formed in elastomeric sealing ring 110b and rigid dynamic sealing ring 120a, respectively. In other embodiments, protrusion 115 and notch 123 are formed in rigid dynamic sealing ring 120a and elastomeric sealing ring 110b, respectively.

[0112] As mentioned above, when elastomeric sealing ring 110b and rigid dynamic sealing ring 120a are engaged together, their rotation relative to each other is restricted. The rotation of elastomeric sealing ring 110b and rigid dynamic sealing ring 120a relative to each other is restricted because elastomeric sealing ring protrusion 115 engages a portion of rigid dynamic sealing ring body 121a (FIG. 15a) that bounds rigid dynamic sealing ring notch 123. Further, as mentioned above, elastomeric sealing ring 110b will rotate with cutting cone 102 because they are frictionally engaged together. Hence, rigid dynamic sealing ring 120a will rotate in response to the rotation of cutting cone 102 because elastomeric sealing ring 110b and rigid dynamic sealing ring 120a are engaged together with joint 116. In this way, rigid dynamic sealing ring 120a is less likely to lock and undesirably form a static seal with lug 101 in response to mud packing.

[0113] In the embodiment indicated by indication arrow 156 of FIG. 12, elastomeric sealing ring 110b will not rotate with cutting cone 102 because elastomeric sealing ring 110b is frictionally engaged with lug 101. Hence, rigid dynamic sealing ring 120a will not rotate in response to the rotation of cutting cone 102 because elastomeric sealing ring 110b and rigid dynamic sealing ring 120a are engaged together with joint 116. In this way, rigid dynamic sealing ring 120a is less likely to lock and undesirably form a static seal with cutting cone 102 in response to mud packing. [0114] Elastomeric sealing ring 110b provides many different functions. For example, one function of elastomeric sealing ring 110b is to operate as a diaphragm. Elastomeric sealing ring 110b operates as a diaphragm because elastomeric sealing ring arm 113 separates internal region 108 and external region 109 (FIGS. Ib and 12) . Further, elastomeric sealing ring 110b operates as a diaphragm because, as described below, elastomeric sealing ring arm 113 allows rigid dynamic sealing ring 120a to move relative to elastomeric sealing ring body 111.

[0115] Elastomeric sealing ring 110b functions to bias rigid dynamic sealing ring 120a against lug 101 (FIG. 12) or cutting cone 102 (FIG. 12, indication arrow 156), so that the dynamic seal formed by rigid dynamic sealing ring 120a is less likely to break. Further, elastomeric sealing ring 110b biases rigid dynamic sealing ring 120a against lug 101 or cutting cone 102 so that the dynamic seal is less likely to break in response to misalignment of lug 101 and cutting cone 102. For example, in some embodiments, elastomeric sealing ring 110b biases rigid dynamic sealing ring 120a against lug 101 so that the dynamic seal between rigid dynamic sealing ring 120a and lug 101 is stronger and less likely to break. In the embodiment indicated by indication arrow 156, elastomeric sealing ring 110b biases rigid dynamic sealing ring 120a against cutting cone 102 so that the dynamic seal between rigid dynamic sealing ring 120a and cutting cone 102 is stronger and less likely to break. It is desirable to reduce the likelihood of the dynamic seal breaking to reduce the likelihood of debris entering and lubricant leaving internal region 108. Hence, it is desirable to bias rigid dynamic sealing ring 120a against lug 101 or cutting cone 102.

[0116] Elastomeric sealing ring 110b can bias rigid dynamic sealing ring 120a against lug 101 or cutting cone 102 in many different ways. In this embodiment, elastomeric sealing ring 110b biases rigid dynamic sealing ring 120a against lug 101 or cutting cone 102 because elastomeric sealing ring 110b transmits, in axial direction 105 (FIG. Ib), an axial force to rigid dynamic sealing ring 120a. The axial force allows elastomeric sealing ring 110b to repeatably move between unflexed and flexed conditions, as shown in FIGS. 15b and 15c, respectively. Elastomeric sealing ring 110b can move between unflexed and flexed conditions because elastomeric sealing ring arm 113 can move between unflexed and flexed conditions .

[0117] In general, elastomeric sealing ring arm 113 is in the unflexed condition in response to rigid dynamic sealing ring 120a being disengaged from lug 101 (FIG. 12) and cutting cone 102 (FIG. 12, indication arrow 156) . Elastomeric sealing ring arm 113 is in the flexed condition in response to rigid dynamic sealing ring 120a engaging lug 101 (FIG. 12) or cutting cone 102 (FIG. 12, indication arrow 156) . In this embodiment, when elastomeric sealing ring arm 113 moves from the unflexed condition to the flexed condition, surface 117a, sealing ring 120a and protrusion 115 move towards surface 118a. Further, when elastomeric sealing ring arm 113 moves from the flexed condition to the unflexed condition, surface 117a, sealing ring 120a and protrusion 115 move away from surface 118a. In this way, elastomeric sealing ring 110b moves between unflexed and flexed conditions, and biases rigid dynamic sealing ring 120a against lug 101 or cutting cone 102.

[0118] It should be noted that rigid dynamic sealing ring 120a moves relative to rigid reinforcement ring 125 and elastomeric sealing ring body 111 in response to elastomeric sealing ring arm 113 moving between unflexed and flexed conditions. Elastomeric sealing ring 110b allows rigid dynamic sealing ring 120a to move because elastomeric sealing ring 110b transmits, in axial direction 105 (FIG. Ib), an axial force to rigid dynamic sealing ring 120a. Rigid dynamic sealing ring 120a moves relative to elastomeric sealing ring 110b so it can be biased against lug 101 or cutting cone 102, as described above. In general, rigid dynamic sealing ring 120a moves in axial direction 105.

[0119] In the embodiment of FIG. 12, elastomeric sealing ring arm 113 allows rigid dynamic sealing ring 120a to be biased against lug 101. In general, rigid dynamic sealing ring 120a is biased more against lug 101 in response to increasing the stiffness of elastomeric sealing ring arm 113. The stiffness of elastomeric sealing ring arm 113 can be increased and decreased as described above with elastomeric sealing ring 110a.

[0120] Rigid dynamic sealing ring 120a is forced more against lug 101 in response to the stiffness of elastomeric sealing ring arm 113 being increased. When rigid dynamic sealing ring 120a is biased more against lug 101, rigid dynamic sealing ring 120a engages lug 101 to form a stronger dynamic seal between them. Further, rigid dynamic sealing ring 120a is biased less against lug 101 in response to decreasing the stiffness of elastomeric sealing ring arm 113. Rigid dynamic sealing ring 120a is forced less against lug 101 in response to the stiffness of elastomeric sealing ring arm 113 being decreased. When rigid dynamic sealing ring 120a is biased less against lug 101, rigid dynamic sealing ring 120a forms a weaker dynamic seal with lug 101. It is generally desirable to form a stronger dynamic seal between lug 101 and rigid dynamic sealing ring 120a to reduce the likelihood of the dynamic seal breaking and to reduce the likelihood of debris entering and lubricant leaving region 108. It should be noted that the amount of bias applied by elastomeric sealing ring 110b to rigid dynamic sealing ring 120a can be increased because, as mentioned above, rigid dynamic sealing ring 120a is less likely to lock with lug 101 because it is engaged with elastomeric sealing ring 110b. [0121] In the embodiment indicated by indication arrow 156 of FIG. 12, elastomeric sealing ring arm 113 allows rigid dynamic sealing ring 120a to be biased against cutting cone 102. In general, rigid dynamic sealing ring 120a is biased more against cutting cone 102 in response to increasing the stiffness of elastomeric sealing ring arm 113. Rigid dynamic sealing ring 120a is forced more against cutting cone 102 in response to the stiffness of elastomeric sealing ring arm 113 being increased. When rigid dynamic sealing ring 120a is biased more against cutting cone 102, rigid dynamic sealing ring 120a engages lug cutting cone 102 to form a stronger dynamic seal between them. Further, rigid dynamic sealing ring 120a is biased less against cutting cone 102 in response to decreasing the stiffness of elastomeric sealing ring arm 113. Rigid dynamic sealing ring 120a is forced less against cutting cone 102 in response to the stiffness of elastomeric sealing ring arm 113 being decreased. When rigid dynamic sealing ring 120a is biased less against cutting cone 102, rigid dynamic sealing ring 120a forms a weaker dynamic seal with cutting cone 102.

[0122] FIG. 16 is a cut-away side view of rotary earth bit 100, which includes a seal assembly 130c, in accordance with the invention. FIGS. 17a and 17b are top and bottom exploded perspective views of seal assembly 130c. Seal assembly 130c is positioned within seal region 104 to retain lubricant between lug 101 and cutting cone 102. Further, seal assembly 130c is positioned within seal region 104 to restrict the flow of debris to internal region 108 between lug 101 and cutting cone 102. [0123] In this embodiment, seal assembly 130c includes elastomeric sealing ring 110c (FIGS. 4a and 4b) which carries rigid reinforcement ring 125 (FIGS. 7a and 7b) . Rigid reinforcement ring 125 reinforces elastomeric sealing ring 110c. Further, seal assembly 130c includes rigid dynamic sealing ring 120b (FIGS. 6a and 6b) which carries elastomeric friction ring 127. Rigid dynamic sealing ring 120b reduces the likelihood that elastomeric sealing ring 110c will become impregnated with debris. Elastomeric friction ring 127 helps rigid dynamic sealing ring 120b maintain a dynamic seal with lug 101 or cutting cone 102. Elastomeric sealing ring 110c, rigid dynamic sealing ring 120b, rigid reinforcement ring 125 and elastomeric friction ring 127 are statically sealed together. In particular, elastomeric sealing ring 110c, rigid dynamic sealing ring 120b, rigid reinforcement ring 125 and elastomeric friction ring 127 are statically sealed together so they operate as a single integral seal.

[0124] FIGS. 18a and 18b are top and bottom perspective views of elastomeric sealing ring 110c, rigid dynamic sealing ring 120b, rigid reinforcement ring 125 and elastomeric friction ring 127 statically sealed together. Rigid reinforcement ring 125 is received by elastomeric sealing ring groove 112, as shown in FIGS. 4a and 18b, so that rigid dynamic sealing ring 120b and rigid reinforcement ring 125 are coupled together by elastomeric sealing ring 110c. In this embodiment, elastomeric sealing ring groove 112 receives rigid reinforcement ring 125 so that rigid reinforcement ring 125 does not form a static or dynamic seal with lug 101 or cutting cone 102. In other embodiments of sealing ring 110b, such as those which utilize groove 112 embodied as indicated by indication arrow 151b (FIG. 3a), rigid reinforcement ring 125 can form a static seal with lug 101 or cutting cone 102. Rigid reinforcement ring 125 can form a static seal with lug 101 when it is received by groove 112 embodied as indicated by indication arrow 151b, and elastomeric sealing ring 110b is oriented as indicated by indication arrow 155 of FIG. 8. Elastomeric sealing ring 110c and rigid reinforcement ring 125 can be statically sealed together in many different ways. In this embodiment, elastomeric sealing ring 110c and rigid reinforcement ring 125 are bonded together using an adhesive .

[0125] Elastomeric friction ring 127 is received by rigid dynamic sealing ring groove 122, as shown in FIGS. 6a and 18a, so that elastomeric friction ring 127 and rigid dynamic sealing ring 120b are statically sealed together. Elastomeric friction ring 127 and rigid dynamic sealing ring 120b can be statically sealed together in many different ways. In this embodiment, elastomeric friction ring 127 and rigid dynamic sealing ring 120b are bonded together. Elastomeric friction ring 127 and rigid dynamic sealing ring 120b can be bonded together in many different ways, such as by using an adhesive.

[0126] In general, elastomeric sealing ring 110c forms a static seal with lug 101 or cutting cone 102. For example, in this embodiment, it is desirable for elastomeric sealing ring 110c to form a static seal with cutting cone 102 so that elastomeric sealing ring 110c and rigid reinforcement ring 125 rotate in response to the rotation of cutting cone 102. It is also desirable in this embodiment for elastomeric friction ring 127 to form a static seal with cutting cone 102. Further, in this embodiment, it is desirable for rigid dynamic sealing ring 120b to form a dynamic seal with lug 101. Rigid dynamic sealing ring rotates in response to the rotation of cutting cone 102 because, as discussed in more detail below, elastomeric sealing ring 110c restricts the rotation of rigid dynamic sealing ring 120b. In this way, rigid dynamic sealing ring 120b is more likely to form a dynamic seal with lug 101 and is less likely to form a static seal with lug 101. Hence, rigid dynamic sealing ring 120b is less likely to lock and undesirably form a static seal with lug 101, or a dynamic seal with elastomeric sealing ring 110c, in response to mud packing. Further, elastomeric friction ring 127 is more likely to form a static seal with cutting cone 102 and is less likely to form a dynamic seal with cutting cone 102.

[0127] It should be noted that, in this embodiment, dynamic sealing surface 117a is between seal assembly 130c and journal segment 101a, and static sealing surfaces 118a and 118b are between seal assembly 130c and cutting cone 102. In this way, seal assembly 130c forms a dynamic seal with lug 101 and a static seal with cutting cone 102. In particular, elastomeric sealing ring 110c frictionally engages cutting cone 102 so elastomeric sealing ring 110c will rotate with cutting cone 102. Further, elastomeric sealing ring 110c frictionally engages cutting cone 102 so a static seal is formed between them. Elastomeric sealing ring 110c forms a static seal with cutting cone 102 to reduce the likelihood of lubricant leaving and debris entering internal region 108. In the alternative embodiment indicated by indication arrow 151b in FIG. 3a, rigid reinforcement ring 125 faces static sealing surface 118b and forms a static seal with cutting cone 102. In this way, rigid reinforcement ring 125 forms an interference fit with cutting cone 102.

[0128] In another embodiment, such as the embodiment indicated by an indication arrow 157 of FIG. 16, elastomeric sealing ring 110c forms a static seal with lug 101 so that elastomeric sealing ring 110c and rigid reinforcement ring 125 do not rotate in response to the rotation of cutting cone 102. It is also desirable in this embodiment for elastomeric friction ring 127 to form a static seal with lug 101. Further, in this embodiment, it is desirable for rigid dynamic sealing ring 120b to form a dynamic seal with cutting cone 102. Rigid dynamic sealing ring 120b does not rotate in response to the rotation of cutting cone 102 because, as discussed in more detail below, elastomeric sealing ring 110c restricts the rotation of rigid dynamic sealing ring 120b. In this way, rigid dynamic sealing ring 120b is more likely to form a dynamic seal with cutting cone 102 and is less likely to form a static seal with cutting cone 102. Hence, rigid dynamic sealing ring 120b is less likely to lock and undesirably form a static seal with cutting cone 102, or a dynamic seal with elastomeric sealing ring 110c, in response to mud packing. Further, elastomeric friction ring 127 is more likely to form a static seal with lug 101 and is less likely to form a dynamic seal with lug 101. It should be noted that any of the embodiments of elastomeric sealing rings, such as those indicated by indication arrows 150a, 150b, 151a, 151b, 152a and 152b, can be positioned in region 104 as indicated by indication arrow 157.

[0129] It should also be noted that, in the embodiment indicated by indication arrow 157, static sealing surfaces 118a and 118b are between seal assembly 130c and journal segment 101a, and dynamic sealing surface 117a is between seal assembly 130c and cutting cone 102. In this way, in the embodiment indicated by indication arrow 157, seal assembly 130c forms a static seal with lug 101 and a dynamic seal with cutting cone 102. In particular, elastomeric sealing ring 110c frictionally engages lug 101 so elastomeric sealing ring 110c will not rotate with cutting cone 102. Further, elastomeric sealing ring 110c frictionally engages lug 101 so a static seal is formed between them. Elastomeric sealing ring 110c forms a static seal with lug 101 to reduce the likelihood of lubricant leaving and debris entering internal region 108.

[0130] In accordance with the invention, elastomeric sealing ring 110c restricts the rotation of rigid dynamic sealing ring 120b. For example, in the embodiments of sealing rings which do not include a reinforcement ring, such as the embodiment indicated by indication arrow 152b of FIG. 4a, elastomeric sealing ring 110c restricts the rotation of rigid dynamic sealing ring 120b relative to elastomeric sealing ring body 111. In the embodiments which include a rigid reinforcement ring, elastomeric sealing ring 110c restricts the rotation of rigid dynamic sealing ring 120b relative to the rigid reinforcement ring. Elastomeric sealing ring 110c restricts the rotation of rigid dynamic sealing ring 120b so that their relative rotation is driven to zero. Elastomeric sealing ring 110c restricts the rotation of rigid dynamic sealing ring 120b relative to rigid reinforcement ring 125 so that rigid dynamic sealing ring 120b and rigid reinforcement ring 125 rotate together. In some embodiments, elastomeric sealing ring 110c restricts the rotation of rigid dynamic sealing ring 120b relative to rigid reinforcement ring 125 so that rigid dynamic sealing ring 120b rotates in response to the rotation of rigid reinforcement ring 125. Hence, rigid dynamic sealing ring 120b is more likely to rotate in response to the rotation of elastomeric sealing ring 110c and rigid reinforcement ring 125. In this way, elastomeric sealing ring 110c and rigid dynamic sealing ring 120b are more likely to remain statically sealed together, and less likely to be dynamically sealed together. Elastomeric sealing ring 110c can restrict the rotation of rigid dynamic sealing ring 120b relative to rigid reinforcement ring 125 in many different ways, one of which will be discussed in more detail presently.

[0131] FIG. 19a is a close-up view of seal assembly 130c showing elastomeric sealing ring arm 113 being received by rigid dynamic sealing ring groove 124 (FIGS. 6a and 6b) . FIGS. 19b and 19c are cut-away side views of seal assembly 130c taken along a cut-line 15a-15a of FIG. 19a showing elastomeric sealing ring arm 113 being received by rigid dynamic sealing ring groove 124. It should be noted that elastomeric sealing ring 113 is shown in unflexed and flexed conditions, respectively, in FIGS. 19b and 19c. One way in which elastomeric sealing ring 110c restricts the rotation of rigid dynamic sealing ring 120b relative to rigid reinforcement ring 125 is by engaging elastomeric sealing ring arm 113 with rigid dynamic sealing ring 120b. Elastomeric sealing ring arm 113 can be engaged with rigid dynamic sealing ring 120b in many different ways.

[0132] In this embodiment, elastomeric sealing ring arm 113 is engaged with rigid dynamic sealing ring 120b by extending arm 113 through rigid dynamic sealing ring groove 124. Elastomeric sealing ring arm 113 can be engaged with rigid dynamic sealing ring 120b within rigid dynamic sealing ring groove 124 in many different ways. In this embodiment, elastomeric sealing ring arm 113 and rigid dynamic sealing ring 120b are bonded together within rigid dynamic sealing ring groove 124. Elastomeric sealing ring arm 113 and rigid dynamic sealing ring 120b can be bonded together in many different ways, such as by using an adhesive.

[0133] It should be noted that, in this embodiment, elastomeric sealing ring arm 113 is spaced from lug 101 by rigid dynamic sealing ring 120b. Hence, rigid dynamic sealing ring 120b is positioned between dynamic sealing surface 117a and elastomeric sealing ring 110c. In this way, rigid dynamic sealing ring 120b reduces the likelihood that elastomeric sealing ring 110c will become impregnated with debris.

[0134] As mentioned above, when elastomeric sealing ring 110c and rigid dynamic sealing ring 120b are engaged together, their rotation relative to each other is restricted. The rotation of elastomeric sealing ring 110c and rigid dynamic sealing ring 120b relative to each other is restricted because elastomeric sealing ring arm 113 is bonded to rigid dynamic sealing ring 120b. Further, as mentioned above, elastomeric sealing ring 110c will rotate with cutting cone 102 because they are frictionally engaged together. Hence, rigid dynamic sealing ring 120b will rotate in response to the rotation of cutting cone 102 because elastomeric sealing ring 110c and rigid dynamic sealing ring 120b are engaged together with arm 113. In this way, rigid dynamic sealing ring 120b is less likely to lock and undesirably form a static seal with lug 101, or a dynamic seal with elastomeric sealing ring 110c, in response to mud packing.

[0135] In the embodiment indicated by indication arrow 157 of FIG. 16, elastomeric sealing ring 110c will not rotate with cutting cone 102 because elastomeric sealing ring 110c is frictionally engaged with lug 101. Hence, rigid dynamic sealing ring 120b will not rotate in response to the rotation of cutting cone 102 because elastomeric sealing ring 110c and rigid dynamic sealing ring 120b are engaged together with arm 113. In this way, rigid dynamic sealing ring 120b is less likely to lock and undesirably form a static seal with cutting cone 102, or a dynamic seal with elastomeric sealing ring 110c, in response to mud packing. [0136] Elastomeric sealing ring 110c provides many different functions. For example, one function of elastomeric sealing ring 110c is to operate as a diaphragm. Elastomeric sealing ring 110c operates as a diaphragm because elastomeric sealing ring arm 113 separates internal region 108 and external region 109 (FIGS. Ib and 16) . Further, elastomeric sealing ring 110c operates as a diaphragm because, as described below, elastomeric sealing ring arm 113 allows rigid dynamic sealing ring 120b to move relative to elastomeric sealing ring body 111.

[0137] Elastomeric sealing ring 110c functions to bias rigid dynamic sealing ring 120b against lug 101 (FIG. 16) or cutting cone 102 (FIG. 16, indication arrow 157), so that the dynamic seal formed by rigid dynamic sealing ring 120b is less likely to break. Further, elastomeric sealing ring 110c biases rigid dynamic sealing ring 120b against lug 101 or cutting cone 102 so that the dynamic seal is less likely to break in response to the misalignment of lug 101 and cutting cone 102. For example, in some embodiments, elastomeric sealing ring 110c biases rigid dynamic sealing ring 120b against lug 101 so that the dynamic seal between rigid dynamic sealing ring 120b and lug 101 is stronger and less likely to break. In the embodiment indicated by indication arrow 156, elastomeric sealing ring 110c biases rigid dynamic sealing 120b ring against cutting cone 102 so that the dynamic seal between rigid dynamic sealing ring 120b and cutting cone 102 is stronger and less likely to break. It is desirable to reduce the likelihood of the dynamic seal breaking to reduce the likelihood of debris entering and lubricant leaving region 108. Hence, it is desirable to bias rigid dynamic sealing ring 120b against lug 101 or cutting cone 102. [0138] Elastomeric sealing ring 110c can bias rigid dynamic sealing ring 120b against lug 101 or cutting cone 102 in many different ways. In this embodiment, elastomeric sealing ring 110c biases rigid dynamic sealing ring 120b against lug 101 or cutting cone 102 because elastomeric sealing ring 110c transmits, in axial direction 105 (FIG. Ib) , an axial force to rigid dynamic sealing ring 120b. The axial force allows elastomeric sealing ring 110c to repeatably move between unflexed and flexed conditions, as shown in FIGS. 19b and 19c, respectively. Elastomeric sealing ring 110c can move between unflexed and flexed conditions because elastomeric sealing ring arm 113 can move between unflexed and flexed conditions .

[0139] In general, elastomeric sealing ring arm 113 is in the unflexed condition in response to rigid dynamic sealing ring 120b being disengaged from lug 101 (FIG. 16) and cutting cone 102 (FIG. 16, indication arrow 157) . Elastomeric sealing ring arm 113 is in the flexed condition in response to rigid dynamic sealing ring 120b engaging lug 101 (FIG. 16) or cutting cone 102 (FIG. 16, indication arrow 157) . In this embodiment, when elastomeric sealing ring arm 113 moves from the unflexed condition to the flexed condition, surface 117a and sealing ring 120b move towards surface 118a. Further, when elastomeric sealing ring arm 113 moves from the flexed condition to the unflexed condition, surface 117a and sealing ring 120b move away from surface 118a. In this way, elastomeric sealing ring 110c moves between unflexed and flexed conditions, and biases rigid dynamic sealing ring 120b against lug 101 or cutting cone 102. It should be noted that elastomeric sealing ring arm 113 remains in the unflexed condition until positioned in region 104 (FIG. Ib) . Elastomeric sealing ring arm 113 moves from the unflexed condition to the flexed condition in response to cutting cone 102 being coupled with lug 101. Further, sealing ring 120a is biased in response to cutting cone 102 being coupled with lug 101 so a dynamic seal is formed. The dynamic seal is typically formed between sealing ring 120a and lug 101, or between sealing ring 120a and cutting cone 102.

[0140] It should be noted that rigid dynamic sealing ring 120b moves relative to rigid reinforcement ring 125 and elastomeric sealing ring body 111 in response to elastomeric sealing ring arm 113 moving between the unflexed and flexed conditions. Elastomeric sealing ring 110c allows rigid dynamic sealing ring 120b to move because elastomeric sealing ring 110c transmits, in axial direction 105 (FIG. Ib), an axial force to rigid dynamic sealing ring 120b. Rigid dynamic sealing ring 120b moves relative to elastomeric sealing ring 110c so it can be biased against lug 101 or cutting cone 102, as described above. In general, rigid dynamic sealing ring 120b moves in axial direction 105.

[0141] In the embodiment of FIG. 16, elastomeric sealing ring arm 113 allows rigid dynamic sealing ring 120b to be biased against lug 101. In general, rigid dynamic sealing ring 120b is biased more against lug 101 in response to increasing the stiffness of elastomeric sealing ring arm 113. The stiffness of elastomeric sealing ring arm 113 can be increased and decreased as described above with sealing ring 110a.

[0142] Rigid dynamic sealing ring 120b is forced more against lug 101 in response to the stiffness of elastomeric sealing ring arm 113 being increased. When rigid dynamic sealing ring 120b is biased more against lug 101, rigid dynamic sealing ring 120b engages lug 101 to form a stronger dynamic seal between them. Further, rigid dynamic sealing ring 120b is biased less against lug 101 in response to decreasing the stiffness of elastomeric sealing ring arm 113. Rigid dynamic sealing ring 120b is forced less against lug 101 in response to the stiffness of elastomeric sealing ring arm 113 being decreased. When rigid dynamic sealing ring 120b is biased less against lug 101, rigid dynamic sealing ring 120b forms a weaker dynamic seal with lug 101. It is generally desirable to form a stronger dynamic seal between lug 101 and rigid dynamic sealing ring 120b to reduce the likelihood of the dynamic seal breaking and to reduce the likelihood of debris entering and lubricant leaving region 108. It should be noted that the amount of bias applied by elastomeric sealing ring 110c to rigid dynamic sealing ring 120b can be increased because, as mentioned above, rigid dynamic sealing ring 120b is less likely to lock with lug 101 because it is engaged with elastomeric sealing ring 110c. [0143] In the embodiment indicated by indication arrow 157 of FIG. 16, elastomeric sealing ring arm 113 allows rigid dynamic sealing ring 120b to be biased against cutting cone 102. In general, rigid dynamic sealing ring 120b is biased more against cutting cone 102 in response to increasing the stiffness of elastomeric sealing ring arm 113. Rigid dynamic sealing ring 120b is forced more against cutting cone 102 in response to the stiffness of elastomeric sealing ring arm 113 being increased. When rigid dynamic sealing ring 120b is biased more against cutting cone 102, rigid dynamic sealing ring 120b engages cutting cone 102 to form a stronger dynamic seal between them. Further, rigid dynamic sealing ring 120b is biased less against cutting cone 102 in response to decreasing the stiffness of elastomeric sealing ring arm 113. Rigid dynamic sealing ring 120b is forced less against cutting cone 102 in response to the stiffness of elastomeric sealing ring arm 113 being decreased. When rigid dynamic sealing ring 120b is biased less against cutting cone 102, rigid dynamic sealing ring 120b forms a weaker dynamic seal with cutting cone 102.

[0144] FIG. 20a is a flow diagram of a method 200, in accordance with the invention, of providing a seal for an earth bit. In this embodiment, method 200 includes a step 201 of coupling a first elastomeric sealing ring and first rigid ring together and a step 202 of coupling a second rigid ring to the first elastomeric sealing ring to form a seal assembly, wherein the first elastomeric sealing ring restricts the rotation of the second rigid ring relative to the first rigid ring. Method 200 includes a step 203 of positioning the seal assembly to form a seal between a cutting cone and lug. It should be noted that the first rigid ring typically operates as a reinforcement ring, and the second rigid ring typically operates as a sealing ring which forms a dynamic seal with the cutting cone or lug.

[0145] In some embodiments, step 202 of coupling the second rigid ring and first elastomeric sealing ring together includes extending a protrusion through a notch. The extension of a protrusion through a notch is discussed in more detail with FIGS. 11a, lib and lie, as well as FIGS. 15a, 15b and 15c. The protrusion can extend beyond a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. The protrusion can terminate flush with a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. The protrusion can terminate proximate with a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. The termination of a protrusion proximate to a surface of a rigid ring is discussed in more detail with FIGS, lib and lie. In some embodiments, step 202 of coupling the second rigid ring and first elastomeric sealing ring together includes extending an arm through an outwardly facing groove. The extension of an arm through an outwardly facing groove is discussed in more detail with FIGS. 19a, 19b and 19c.

[0146] It should be noted that method 200 can include many other steps. For example, in some embodiments, method 200 includes a step of positioning a second elastomeric sealing ring so it is carried by the second rigid ring. The second elastomeric sealing ring extends beyond a surface opposed to a dynamic sealing surface of the second rigid ring.

[0147] FIG. 20b is a flow diagram of a method 210, in accordance with the invention, of providing a seal for an earth bit. In this embodiment, method 210 includes a step 211 of coupling a first elastomeric sealing ring and first rigid ring together and a step 212 of coupling a second rigid ring to the first elastomeric sealing ring to form a seal assembly, wherein the second rigid ring rotates in response to the rotation of the first elastomeric sealing ring. It should be noted that the first rigid ring typically operates as a reinforcement ring, and the second rigid ring typically operates as a sealing ring which forms a dynamic seal with a cutting cone or lug.

[0148] In some embodiments, step 212 of coupling the second rigid ring and first elastomeric sealing ring together includes extending a protrusion through a notch. The protrusion can extend beyond a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. The protrusion can terminate flush with a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. The protrusion can terminate proximate with a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. The termination of a protrusion proximate to a surface of a rigid ring is discussed in more detail with FIGS. 11a and lib. In some embodiments, step 212 of coupling the second rigid ring and first elastomeric sealing ring together includes extending an arm through an outwardly facing groove.

[0149] In this embodiment, method 210 includes a step 213 of positioning the seal assembly to form a seal between the cutting cone and lug. In some embodiments, the seal assembly is positioned between the cutting cone and lug so that the first elastomeric sealing ring statically seals with the cutting cone and the second rigid ring dynamically seals with the lug. In these embodiments, the first elastomeric sealing ring and second rigid ring are engaged together so that the second rigid ring rotates relative to the lug in response to the rotation of the first elastomeric sealing ring.

[0150] In other embodiments, the seal assembly is positioned between the cutting cone and lug so that the first elastomeric sealing ring dynamically seals with the cutting cone and the second rigid ring statically seals with the lug. In these embodiments, the first elastomeric sealing ring and second rigid ring are engaged together so that the second rigid ring does not rotate relative to the lug in response to the rotation of the cutting cone .

[0151] It should be noted that method 210 can include many other steps. For example, in some embodiments, method 210 includes a step of positioning a second elastomeric sealing ring so it is carried by the second rigid ring. The second elastomeric sealing ring extends beyond a surface opposed to a dynamic sealing surface of the second rigid ring. In the embodiments in which the seal assembly is positioned so that the first elastomeric sealing ring statically seals with the cutting cone and the second rigid ring dynamically seals with the lug, the second elastomeric sealing ring can statically seal with the cutting cone. In the embodiments in which the seal assembly is positioned so that the first elastomeric sealing ring statically seals with the lug and the second rigid ring dynamically seals with the cutting cone, the second elastomeric sealing ring can statically seal with the lug. It should also be noted that the steps of methods 200 and 210 can be carried out in many different orders.

[0152] FIG. 21a is a flow diagram of a method 220, in accordance with the invention, of manufacturing a seal assembly for an earth bit. In this embodiment, method 220 includes a step 221 of providing a first elastomeric sealing ring and reinforcement ring and coupling them together. Method 220 includes a step 222 of providing a rigid dynamic sealing ring and coupling it to the first elastomeric sealing ring. In accordance with the invention, the rigid dynamic sealing ring and first elastomeric sealing ring are coupled together so that the first elastomeric sealing ring restricts the rotation of the second rigid ring relative to the first rigid ring.

[0153] In some embodiments, step 222 includes extending a protrusion through a notch. The protrusion can extend beyond a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. The protrusion can terminate flush with a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. In some embodiments, step 222 includes extending an arm through an outwardly facing groove.

[0154] It should be noted that method 220 can include many other steps. For example, in some embodiments, method 220 includes a step of positioning a second elastomeric sealing ring so it is carried by the second rigid ring. The second elastomeric sealing ring extends beyond a surface opposed to a dynamic sealing surface of the second rigid ring.

[0155] FIG. 21b is a flow diagram of a method 230, in accordance with the invention, of manufacturing a seal assembly for an earth bit. In this embodiment, method 230 includes a step 221 of providing a first elastomeric sealing ring and reinforcement ring and coupling them together. Method 230 includes a step 232 of providing a rigid dynamic sealing ring and coupling it to the first elastomeric sealing ring. In accordance with the invention, the second rigid ring rotates in response to the rotation of the first elastomeric sealing ring. In some embodiments, step 232 includes extending a protrusion through a notch. The protrusion can extend beyond a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. The protrusion can terminate flush with or above a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. In some embodiments, step 232 includes extending an arm through an outwardly facing groove .

[0156] It should be noted that method 230 can include many other steps. For example, in some embodiments, method 230 includes a step of positioning a second elastomeric sealing ring so it is carried by the second rigid ring. The second elastomeric sealing ring extends beyond a surface opposed to a dynamic sealing surface of the second rigid ring. It should also be noted that the steps of methods 220 and 230 can be carried out in many different orders. [0157] FIG. 21c is a flow diagram of a method 240, in accordance with the invention, of manufacturing a seal assembly for an earth bit. In this embodiment, method 240 includes a step 241 of providing a first elastomeric sealing ring and first rigid ring, wherein the elastomeric sealing ring includes an arm. The elastomeric sealing ring is repeatably moveable between flexed and unflexed conditions. Method 240 includes a step 242 of coupling the first elastomeric ring and first rigid ring together, wherein the first rigid ring moves in response to the first elastomeric sealing ring moving between the flexed and unflexed conditions. The first elastomeric sealing ring and first rigid ring are coupled together so that the arm restricts the rotation of the first rigid ring relative to the first elastomeric sealing ring. It should be noted that the first rigid ring typically operates as a sealing ring which forms a dynamic seal with a cutting cone or lug. [0158] In some embodiments, step 242 includes extending a protrusion through a notch. The protrusion can extend beyond a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. The protrusion can terminate flush with a surface of the second rigid ring, wherein the surface is opposed to a dynamic sealing surface of the second rigid ring. In some embodiments, step 242 includes extending an arm through an outwardly facing groove.

[0159] It should be noted that method 240 can include many other steps. For example, in some embodiments, method 240 includes a step of positioning a second elastomeric sealing ring so it is carried by the second rigid ring, and coupling them together. The second elastomeric sealing ring extends beyond a surface opposed to a dynamic sealing surface of the second rigid ring. In some embodiments, method 240 includes a step of positioning a second rigid ring so it is carried by the first elastomeric sealing ring, and coupling them together.

[0160] In some embodiments one or more of the rings included with the seal assembly are coupled together in a single step. For example, in some situations, the first and second rigid rings are coupled with the first elastomeric sealing ring in a single step. In another situation, the first and second elastomeric sealing rings are coupled with the first rigid ring in a single step. In still another situation, the first and second rigid rings and first and second elastomeric sealing rings are coupled together in a single step.

[0161] While particular embodiments of the invention have been shown and described, numerous variations and alternate embodiments will occur to those skilled in the art. Accordingly, it is intended that the invention be limited only in terms of the appended claims .

Claims

1. A seal assembly, comprising: a first rigid ring; and a first elastomeric sealing ring which includes an arm coupled with the first rigid ring, the elastomeric sealing ring being repeatably moveable between flexed and unflexed conditions, wherein the first rigid ring moves in response to the first elastomeric sealing ring moving between the flexed and unflexed conditions .

2. The assembly of claim 1, further including a second rigid ring carried by the first elastomeric sealing ring.

3. The assembly of claim 1, wherein the first rigid ring includes an outwardly facing groove which receives the arm, the arm restricting the rotation of the first rigid ring relative to the first elastomeric sealing ring.

4. The assembly of claim 3, wherein the first elastomeric sealing ring includes a protrusion carried by the arm, the protrusion restricting the rotation of the first rigid ring relative to the first elastomeric sealing ring.

5. The assembly of claim 4, wherein the protrusion extends beyond a surface of the first rigid ring, the surface being opposed to a dynamic sealing surface of the first rigid ring.

6. The assembly of claim 4, wherein the protrusion terminates flush with a surface of the first rigid ring, the surface being opposed to a dynamic sealing surface of the first rigid ring.

7. The assembly of claim 1, further including a second elastomeric sealing ring carried by the first rigid ring, the second elastomeric sealing ring extending beyond a surface opposed to a dynamic sealing surface of the first rigid ring.

8. An earth bit, comprising: a lug and cutting cone; and a seal assembly which includes first and second rigid rings, and a first elastomeric sealing ring which carries the first rigid ring, wherein the second rigid ring rotates in response to the rotation of the first elastomeric sealing ring.

9. The earth bit of claim 8, wherein the first elastomeric sealing ring forms a static sealing surface with the cutting cone, and the second rigid ring forms a dynamic sealing surface with the lug.

10. The earth bit of claim 8, wherein the first elastomeric sealing ring forms a static sealing surface with the lug, and the second rigid ring forms a dynamic sealing surface with the cutting cone .

11. The assembly of claim 8, wherein the first elastomeric sealing ring includes an arm which extends towards the second rigid ring.

12. The assembly of claim 11, wherein the second rigid ring includes an outwardly facing groove which receives the arm.

13. The assembly of claim 11, wherein the first elastomeric sealing ring includes a protrusion carried by the arm, wherein the protrusion engages the second rigid ring.

14. The assembly of claim 13, wherein the protrusion extends beyond a surface opposed to a dynamic sealing surface of the second rigid ring.

15. The assembly of claim 13, wherein the protrusion terminates proximate with a surface opposed to a dynamic sealing surface of the second rigid ring.

16. The assembly of claim 8, further including a second elastomeric sealing ring carried by the second rigid ring, the second elastomeric sealing ring extending beyond a surface opposed to a dynamic sealing surface of the second rigid ring.

17. A method of providing a seal for an earth bit, comprising : coupling a first elastomeric sealing ring and first rigid ring together; coupling a second rigid ring to the first elastomeric sealing ring to form a seal assembly, wherein the first elastomeric sealing ring restricts the rotation of the second rigid ring relative to the first rigid ring; and positioning the seal assembly to form a seal between a cutting cone and lug.

18. The method of claim 17, wherein the step of coupling the second rigid ring and first elastomeric sealing ring together includes extending a protrusion through a notch.

19. The assembly of claim 18, wherein the protrusion extends beyond a surface of the second rigid ring, the surface being opposed to a dynamic sealing surface of the second rigid ring.

20. The assembly of claim 18, wherein the protrusion terminates proximate with a surface of the second rigid ring, the surface being opposed to a dynamic sealing surface of the second rigid ring.

21. The method of claim 17, wherein the step of coupling the second rigid ring and first elastomeric sealing ring together includes extending an arm through an outwardly facing groove.

22. The method of claim 21, further including positioning a second elastomeric sealing ring so it is carried by the second rigid ring, the second elastomeric sealing ring extending beyond a surface opposed to a dynamic sealing surface of the second rigid ring.