Abstract: The shaft seal apparatus is comprised of a first sealing portion, a second sealing portion, a first backup diaphragm and an engagement ring, wherein the first sealing portion has a fit mount portion, a first sealing lip and a reinforcement ring, in which the fit mount portion is retained sealingly in the seal housing side, in which an inner circumferential surface of the first sealing lip sealingly fits against the outer circumferential surface of the shaft for providing a seal against the pressurized fluid, in which the reinforcement ring has a reinforcement portion, a cylindrical portion and a joint portion, the reinforcement portion provides a reinforcement against the fit mount portion side of the first sealing lip, the cylindrical portion is integrally joined with the fit mount portion, the joint portion is disposed in the other end of the cylindrical portion, wherein the second sealing portion has a support portion and a second sealing lip, in which the second sealing portion is made of a resin material

Abstract: A combination seal is attached to a bearing comprising a fixed element and a rotating element which rotate relative to each other, so as to seal an inner side and an outer side of the bearing. The combination seal is comprised of a seal ring and a slinger. The seal ring is comprised of a reinforcing ring and an elastic seal supported by the reinforcing ring. A leading end side of the elastic seal, supported by the reinforcing ring extending toward the slinger, is brought into contact with a surface of the slinger, which is opposite to the seal ring, when the combination seal is attached to the bearing. During a combining work process, when combining the seal ring and the slinger to form the combination seal, a seal lip does not turn over and the seal lip can be held toward a predetermined direction without using a specific jig during the combining work process and without being particularly careful during performance of the combining work process.

Abstract: To prevent deterioration of sealing ability during installation of a second seal ring, facilitate parting of a first seal ring from a mold, and enhance degree of freedom of setting the thickness of a seal lip, a sealing device has a first seal ring (20) integrally formed with an installation ring (10) from a rubber-like elastic material and a second seal ring (30) assembled with the first seal ring (20), the first seal ring (20) has a seal lip (25) formed to project outward from a tip (11a) of a tube section (11) of the installation ring (10), and the seal lip (25) is made to be slidably in close contact with the outer peripheral surface of the second seal ring (30) in a state that with the seal lip (25) is reversed toward the inner periphery of the tube section (11) by insertion of the second seal ring (30).

Abstract: A lip portion consists of two cylindrical axial lips 421, 422 extended in parallel to an axial direction of a seal 4 and in different lengths (a radial lip is obviated). A neck 22 of a cross shaft 2 is formed with a neck slant portion 221 defined by a conical surface inclined at 45° relative to an axis thereof. The two axial lips 421, 422 are pressed against the neck slant portion in the axial direction.

Abstract: A universal joint includes a yoke connected to a cruciform by bearing cup assembly. The bearing cup assembly includes a bearing cup, a bearing and an integral seal deflector retainer. The bearing cup assembly is rotatably coupled to a trunnion of the cruciform. The integral seal deflector retainer includes a case engaging the cruciform to retain the bearing assembly on the trunnion.

Abstract: A unitary sleeve lip seal can be used to provide permanently lubricated sealed bearings in severe service conditions such as the track pins of track-driven vehicles and agricultural equipment. The seal has a labyrinthine exclusion path and multiple dust lips contacting the sleeve in addition to the main sealing lip. A garter spring encircling the main sealing lip may enable the seal to operate at moderately elevated pressures. The sleeve has a radial flange at the outermost end. Elastomeric lips extend between the sleeve flange and a faceplate that terminates the outside end of the seal housing. The seal is packed with water-resistant grease and can, when installed in association with grease-packed bearings can create a permanently lubricated bearing/shaft assembly that requires no re-greasing. Resilient coatings both protect the sleeve and case and also improve leak resistance, especially when the seal is retrofitted onto shafts that have been damaged.

Abstract: A seal assembly has simple assembly structures, and provides secure sealing effects. A crawler-track connection structure allows the seal assembly to be easily mounted, and securely prevents overflow of a lubricant and the like to the outside. A pair of seal rings (1) and (1) individually having lip portions (23) and (23) are disposed such that each of the lip portions (23) and (23) protrudes in a direction opposing an axial direction, and a load seal ring (2) is compressed and inserted between the pair of seal rings (1) and (1). The load seal ring (2) exerts reaction forces on the pair of lip portions (23) and (23) outwardly in the axial direction.

Abstract: A seal assembly has simple assembly structures, and provides secure sealing effects. A crawler-track connection structure allows the seal assembly to be easily mounted, and securely prevents overflow of a lubricant and the like to the outside. A pair of seal rings (1) and (1) individually having lip portions (23) and (23) are disposed such that each of the lip portions (23) and (23) protrudes in a direction opposing an axial direction, and a load seal ring (2) is compressed and inserted between the pair of seal rings (1) and (1). The load seal ring (2) exerts reaction forces on the pair of lip portions (23) and (23) outwardly in the axial direction.

Abstract: To reduce a sliding resistance to the rotation member, and whereby to reduce a torque, a thickness of an inner diameter side lip is formed to be larger than a thickness of an outer diameter side lip, and the outer diameter side lip is formed thinner than the inner diameter side lip in thickness. A depression for inhibiting both the lips from pulling at each other is provided between the inner diameter side lip and the grease lip. A bent portion for reducing a close contact load applied to a rotation member is provided in an intermediate portion in a longitudinal direction of the inner diameter side lip.

Abstract: A sealing device for sealing off an opening between a shaft and a grease-lubricated split bearing housing comprises two halves divided by a diametrical cut and each having a main body arranged in a circumferential groove in the bearing housing opening. The sealing device is provided with sealing lips spaced apart from each other and forming an intermediate grease reservoir, and reinforcing portions arranged between the main seal body and the sealing lips to facilitate sealing engagement between the sealing lips and a shaft when an upper bearing housing half arranged with the upper seal half is mounted onto the shaft while the shaft is resting in a lower bearing housing half arranged with the lower seal half.

Abstract: A ring-like lubricant supply device 6 is fitted into a recess 4 of a nut member 2. The lubricant supply device 6 contains a lubricant and is formed in an outer peripheral surface with notches 7. Tubular members 8 each having an outer diameter larger than the diameter of the notch 7 are inserted into the notches, pushing and widening the notches 7 in a circumferential direction. One end of the tubular member 8 is fitted into a recess 9b of a retaining ring 9 and the retaining ring 9 is fixed to a nut member 2.

Abstract: A slip joint includes first and second shafts that are connected for concurrent rotational movement and for relative axial movement, such as by respective pluralities of axially extending spline. A seal can is secured to the first shaft and extends about a portion of the second shaft. A seal assembly is secured to the second shaft and engages a portion of the seal can. The seal assembly includes first and second seals that are each generally concave in shape. Each of the first and second seals is generally V-shaped in cross section, having a radially innermost end, an intermediate portion, and a radially outermost end, wherein the radially innermost and outermost ends are located closer to one another than the radially intermediate portions. the first and second seals are axially spaced apart from one another so as to define an annular space therebetween that can be filled with a sealing material, such as a waterproof grease.

Abstract: A neck seal is disclosed for use in an oil film bearing assembly for a roll in a rolling mill, the roll having a neck with an intermediate tapered section leading to a reduced diameter end section contained within a sleeve, with the sleeve being fixed in relation to the roll neck and being journalled for rotation in a bushing fixed within a chock. The neck seal is adapted to be mounted on the tapered section of the roll neck for rotation therewith at a location surrounded by a seal end plate fixed to the chock. The neck seal comprises a flexible circular body having axially spaced radially outwardly projecting first and second flanges configured and dimensioned to sealingly contact the seal end plate. First and second axially spaced ridges projecting radially inwardly from the circular body for contact with the tapered section of the roll neck.

Abstract: A unitary sleeve lip seal can be used to provide permanently lubricated sealed bearings in severe service conditions such as the track pins of track-driven vehicles and agricultural equipment. The seal has a labyrinthine exclusion path and multiple dust lips contacting the sleeve in addition to the main sealing lip. A garter spring encircling the main sealing lip may enable the seal to operate at moderately elevated pressures. The sleeve has a radial flange at the outermost end. Elastomeric lips extend between the sleeve flange and a faceplate that terminates the outside end of the seal housing. The seal is packed with water-resistant grease and can, when installed in association with grease-packed bearings can create a permanently lubricated bearing/shaft assembly that requires no re-greasing. Resilient coatings both protect the sleeve and case and also improve leak resistance, especially when the seal is retrofitted onto shafts that have been damaged.

Abstract: A bearing seal for a water pump of an automobile has rolling elements between an outer ring fixed to a casing and a rotary shaft that is provided with a drive portion at one end and an impeller at the other end. In addition, a seal is formed between the outer ring and the rotary shaft by an annular seal body fixed to each end of the outer ring. The seal body on at least the impeller end of the rotary shaft is made of hydrogenated nitrile rubber, to achieve a seal body that is inexpensive but does not deform, even when used in a high-temperature environment in contact with cooling water in a long time.

Abstract: In an oil seal of a hydraulic shock absorber, the oil seal is made of a nitrile rubber of a low nitrile, and an inner diameter of a second lip is set to be smaller within a range between 0.3 and 1.0 mm &phgr; than an outer diameter of a piston rod.

Abstract: A seal element mountable on the tapered section of a roll neck in a rolling mill comprising a notch and/or non-perpendicularly disposed water-side flange which serve to accommodate any tendency for the water-side flange to distort in the stressed state.

Abstract: An elastomer lip member with its rear supported by a pressure resisting back-up ring, and a synthetic resin lip member arranged on a rear side of the elastomer lip are comprised, and on the inner circumferential surface of the seal lip portion of the elastomer lip member, helical grooves generating a pumping action of a fluid introducing direction from an inner space of machine side when a shaft rotates are formed. When a pressure in the inner space of machine is MPa (gage), by making a contact width between the seal lip portion of the elastomer lip member and a shaft at least 0.6 mm, so that a surface pressure maximum portion of the seal lip portion of the elastomer lip member to the shaft is biased or maldistributed toward its rear side whereby a fluid introduction by said helical grooves is performed satisfactorily.

Abstract: A unitary sleeve lip seal can be used to provide permanently lubricated sealed bearings in severe service conditions such as the track pins of track-driven vehicles and agricultural equipment. The seal has a labyrinthine exclusion path and multiple dust lips contacting the sleeve in addition to the main sealing lip. A garter spring encircling the main sealing lip may enable the seal to operate at moderately elevated pressures. The sleeve has a radial flange at the outermost end. Elastomeric lips extend between the sleeve flange and a faceplate that terminates the outside end of the seal housing. The seal is packed with water-resistant grease and can, when installed in association with grease-packed bearings can create a permanently lubricated bearing/shaft assembly that requires no re-greasing. Resilient coatings both protect the sleeve and case and also improve leak resistance, especially when the seal is retrofitted onto shafts that have been damaged.

Abstract: A unitary sleeve lip seal can be used to provide permanently lubricated sealed bearings in severe service conditions such as the track pins of track-driven vehicles and agricultural equipment. The seal has a labyrinthine exclusion path and multiple dust lips contacting the sleeve in addition to the main sealing lip. A garter spring encircling the main sealing lip may enable the seal to operate at moderately elevated pressures. The sleeve has a radial flange at the outermost end. Elastomeric lips extend between the sleeve flange and a faceplate that terminates the outside end of the seal housing. The seal is packed with water-resistant grease and can, when installed in association with grease-packed bearings can create a permanently lubricated bearing/shaft assembly that requires no re-greasing. Resilient coatings both protect the sleeve and case and also improve leak resistance, especially when the seal is retrofitted onto shafts that have been damaged.

Abstract: A shaft sealing assembly for a compressor includes first and second lip rings, each of which is disposed around a shaft of a compressor to provide sealing. A retainer ring is disposed between the two lip rings to retain the shape of the first lip ring, which serves to allow leakage of fluid when the shaft rotates and prevent the leakage when the shaft is stopped. The three rings are held together at the radial portions of the rings. Each of the radial portions of the two lip rings extends outwardly beyond the radial portion of the retainer ring, providing an annular contact area. The two lip rings resiliently contact one another in the contact area. An annular projection is provided on at least one of the lip rings in the contact area to ensure the sealing.

Abstract: An oil seal or fluid seal for providing a seal between a cylinder and a piston rod is provided. The oil seal has an annular seal lip which has on a conical inner circumferential surface thereof a plurality of annular projections which are arranged axially of the seal lip. One of the annular projections which is located more axially outside of the cylinder is larger in the height above the inner circumferential surface than one of the annular projections which is located more axially inside of the cylinder. By this, under a condition where the annular projections which are located more axially inside of the cylinder are subjected to a high pressure within the cylinder, the annular projections which are located more axially inside of the cylinder and the annular projections which are located more axially outside of the cylinder are nearly equal in the contact pressure against the piston rod, thus causing all of the annular projections to deform nearly equally.

Abstract: This invention relates to a seal for protecting an end of an idler roll against contaminants. The seal includes a fastener engageable with the end of the idler roll and an integral first sealing member molded onto the fastener and extending radially outward from the fastener. A second sealing member is integrated with the first sealing member. The first sealing member and the second sealing member project into frictional engagement with the end of the idler roll. When assembled with the end of the idler roll, the first sealing member and the sealing member are biased into frictional engagement with the end of the idler roll, thus protecting the end of the idler roll from contaminants in wet environments.

Abstract: A lip-type fluid seal (10) for a shaft includes a composite sealing lip (26) having an elastomeric portion (32) and a PTFE portion (36). The elastomeric portion (32) includes a lip edge (33) that extends circumferentially continuously to seal the adjacent lip edge (37) of the PTFE portion (36) from any contaminants on the elastomeric side (28) of the seal (10). The PTFE portion (32) has a greater hardness and modulus of elasticity which serves to limit the wear of the elastomeric portion (32) and to induce hydrodynamic surface deformations on the elastomeric lip portion (32) during operation to enhance the exclusion of contaminants. The PTFE lip edge (37) performs well under low temperature and/or low lubricity conditions and its relative hardness protects the elastomeric lip edge from excessive wear.

Abstract: A unitary sleeve lip seal can be used to provide permanently lubricated sealed bearings in severe service conditions such as the track pins of track-driven vehicles and agricultural equipment. The seal has a labyrinthine exclusion path and multiple dust lips contacting the sleeve in addition to the main sealing lip. A garter spring encircling the main sealing lip may enable the seal to operate at moderately elevated pressures. The sleeve has a radial flange at the outermost end. Elastomeric lips extend between the sleeve flange and a faceplate that terminates the outside end of the seal housing. The seal is packed with water-resistant grease and can, when installed in association with grease-packed bearings can create a permanently lubricated bearing/shaft assembly that requires no re-greasing. Resilient coatings both protect the sleeve and case and also improve leak resistance, especially when the seal is retrofitted onto shafts that have been damaged.

Abstract: The follow-up performance to the operation of a shaft is improved by forming an annular space between a rubber seal lip formed of a rubber-like elastic material and a resin seal lip so as to prevent the resin seal lip from interfering with the rubber seal lip. The follow-up performance to the shaft is further improved by increasing the flexibility of the resin seal lip by forming a plurality of annular grooves parallel to one another to the side surface of the annular gap side of the resin seal lip. A PTFE sheet is inserted as in the form of a flat washer shape into a mold, it is adhesively baked to a first seal member formed of rubber together with the vulcanization formation, a plurality of annular grooves and a helical groove are formed to the PTFE sheet by utilizing a mold clamping pressure, and the PTFE sheet is bent at the mold separation time after the molding process.

Abstract: A sealing structure for the shaft of a compressor. The sealing apparatus includes an inner ring, and outer ring, and a support ring. The inner ring and the outer rings have flexible annular lips that contact the surface of the rotary shaft. The support ring supports the inner lip and determines the position of the inner lip. The first lip permits fluid leakage along the surface of the shaft, while the second lip forms a fluid-tight seal with the shaft. The support ring prevents the internal pressure of the compressor from pressing the first lip against the shaft with excessive force, which extends the life of the sealing apparatus.

Abstract: A rolling contact bearing is described with a sealing device suitable to discharge the electrostatic currents which accumulate in a autovehicle; the sealing device (13, 32) has at least one sealing element (17, 37, 43) made of elastic conductive material integral with the stationary race (11) of the bearing and said sealing element engages, by sliding contact, a surface (21, 22, 40, 41, 33) integral with the rotating race (10, 35) of the bearing. The sealing element made of elastic conductive material (17, 37, 43) co-operates with the sealing device (13, 32) to form a hermetically sealed chamber (26, 24, 39, 44); said chamber contains electrically conductive grease and is placed between the outside environment and the bearing inner portions (14) which normally contain lubricant grease.

Abstract: A device is provided for sealing a rotor shaft supported on a bearing mounted in a housing of an appliance for compressing or expanding a fluid containing, apart from the housing, at least one rotor mounted therein. The sealing device is situated between the rotor and the bearing around the rotor shaft and includes at least two zero contact or frictionless seals. The sealing device successively includes between the rotor and the bearing a first zero contact seal; a double, reverse lip seal with two lips; and a second zero contact seal. The two lips are partly directed towards one another and partly directed towards the rotor shaft along their backsides. An entry for fluid under pressure opens between the lips, whereby the lips, depending on the pressure between them, are in contact with to the rotor shaft or are lifted from the rotor shaft.

Abstract: A rotary shaft seal having an elastomer seat for fitting into the bore of a hub or for the attachment onto a shaft comprises a seal washer, connected to a metal enforcement ring through a elastomer intermediate layer. The elastomer intermediate layer consists of a material having a chemical endurance comparable to that of PTFE, in particular of fluorocaoutchouc, and has a thickness of less than 0.5 mm, preferably in the range of 0.05 mm to 0.5 mm. This intermediate layer connects the seal washer with the enforcement ring according to a method according to the invention by simultaneously vulcanization with the elastomer seat on the outer side of the enforcement ring, wherein the injection pressure acting during injection and vulcanization is kept away from the intermediate layer.

Abstract: A rolling bearing with seal has a stationary inner race and rotatable outer race, a first sealing ring faced to the external space and mounted to the inner peripheral end portion of the outer race which rotates during use, so that even if foreign matter in the external space such as muddy water adheres to the outside surface of the first sealing ring, it is slung off by the centrifugal force, while a second sealing ring faced to the balls and mounted to the outer peripheral end portion of the inner race, whereby it is possible to nearly completely prevent the muddy water from penetrating into the space where the rolling elements are located.

Abstract: A sealing assembly for a pump shaft, having a metal supporting structure, and a sealing ring in turn having a main sealing lip and a secondary lip, which extend axially in opposite directions and define an annular cavity together with a lateral surface of the shaft. When undeformed, the diameters of the two lips are such as to respectively determine a predetermined amount of interference and a radial clearance with the shaft. The sealing ring is so formed as to be deformed elastically by the interference fit between the main lip and the shaft, so as to cause the secondary lip to cooperate with the shaft with substantially no interference.

Abstract: A sealing arrangement for a bearing bushing (1), particularly for a rolling bearing-mounted pin (6) of a cardan joint, said sealing arrangement comprising a rotary shaft seal (8) fixed against rotation on the bearing bush (1) by an armoring (3) and bearing sealingly against the pin (6) with a sealing lip (9), an armored fore-seal (5) disposed in front of the rotary shaft seal (8) and secured against rotation on the pin (6) while being supported on an end face (12) of the bearing bushing (1) wherein the rotary shaft seal (8) is made in one-piece with a rubber packing (15) of a sealing material extending towards the open end of the bearing bush (1) and forming a sealing lip (16) which is supported on an armoring (18) of the fore-seal (5).

Abstract: A two piece sealing system for a universal joint assembly. A lubricant seal adapted to prevent the leakage of lubricant between the trunnion and bearing cup of a universal joint wherein the trunnion has a cylindrical portion merging into an outwardly flaring arcuate base portion, the seal including an elastomer body bonded to the interior of a stiffening ring.

Abstract: A radial seal arrangement is disclosed and adapted for use in providing a sealed surface with a shaft. The radial seal arrangement includes an elastomeric member and a metal support member bonded thereto. The elastomeric member includes a first sealing portion that is defined by a lip portion and a second sealing portion defined by a first surface extending at an acute angle from a perpendicular radial surface and a second surface that extends from and is generally perpendicular with the first surface. The metal support member includes a first leg that extends in a linear direction with respect to a reference axis of the seal arrangement and a second leg that extends generally along the perpendicular radial surface. The second leg of the metal support member terminating at a location generally adjacent to the first surface of the second sealing portion.

Abstract: A radial shaft seal for use on a shaft, said radial shaft seal including a rigid insert generally having a L-shaped cross section. The shaft seal including a circumferential seal body molded around the insert. The shaft seal further including an exclusion lip integral with the seal body, the exclusion lip having a venting mechanism. The venting mechanism allows fluid transfer into the primary sealing lip.

Abstract: A hub seal for installation on the wheel end of a heavy duty trailer or truck is disclosed which includes an annular casing defining a radially outer circumferential canal, a thrust ring defined by a ring of polymeric material disposed within the circumferential canal, and an annular sleeve mounted coaxial with the annular casing. The annular sleeve includes a deflector ring configured to mechanically remove at least a portion of the thrust ring upon relative rotation of the casing and sleeve to create a minimal running clearance between the deflector ring and the thrust ring. A method of fabricating a hub seal having a machinable thrust ring is also disclosed.

Abstract: A sealed shaft bearing assembly employs a lubricant seal having a rigid seal case supporting a resilient dust seal in rubbing contact with a cylindrical surface on the shaft, and a labyrinth type primary seal between the dust seal and the interior of the seal case, with the labyrinth being defined by a stator mounted on the seal case and a rotor mounted for rotation with the shaft, and with the stator including a cylindrical tubular portion defining an elongated thin annular gap with the shaft cylindrical surface and the rotor defining an elongated thin annular gap with the outer surface of the rotor. The radial thickness and axial lengths of the thin annular gaps are such as to preclude the passage of grease type lubricant therethrough upon operation of the bearing.

Abstract: A sealing assembly (1) for a rotary shaft (2), having a metal structure (4) defined by a sleeve portion (6) and by a radially inner flange (7), and a sealing ring (5) cooperating in sliding manner with the shaft (2); the sealing ring (5) in turn has a connecting portion (15) for connection to the flange (7), and a portion (18) projecting from the flange; two sealing lips (19, 20) extend axially from opposite sides of the projecting portion (18); the two sealing lips (19, 20) and the projecting portion (18) are connected in one piece to one another at respective narrow sections (21, 22, 23), each defining a respective virtual hinge permitting rotation of each element with respect to the others; and the respective centers of rotation (A, B, C) of the virtual hinges are defined, at each axial section of the sealing assembly, by three points arranged substantially in the form of a triangle.

Abstract: A seal assembly is provided intended to locate sealing means (13, 14) between a housing (10, 11) and another member (15) which may be fixed or rotating. A housing for the sealing member is formed of two parts (10, 11) between which the sealing member is to be located. A first housing part (10) may be in two portions arranged to be fitted together. A second housing part (11) is located between the two portions of the first housing part (10) and a seal (13, 14) is located between the two housing parts. The assembly is secured together by welding the two portions (10A, 10B) of the first housing part.

Abstract: A volumetric pump for administering intravenous fluids to a patient comprises a housing having an elongate cavity therein with an open and a closed end. A resilient sheet of material having a centrally-located aperture covers the open end, and a pump shaft is slidably disposed through the aperture to form a sphincter seal therebetween. An inlet conduit leading from a fluid source (an IV bag) passes through the housing into the cavity near the open end thereof, and an outlet conduit leading to a fluid sink (the patient) passes through the housing from the cavity near the closed end thereof. The shaft is driven back and forth in reciprocating motion inwardly and outwardly of the cavity to produce, respectively, a positive pressure forcing fluid out of the outlet conduit to the fluid sink, and a negative pressure forcing fluid from the fluid source through the inlet conduit.

Abstract: A sealing device comprising a housing 3 provided with an annular piston insert hole 5, an annular piston member 6 slidably inserted into the piston insert hole 5 of the housing 3, and seal lips 7, 8 provided in inner and outer peripheries of the piston member 6 and placed in slidably sealing contact with inner and outer peripheral surfaces of said piston insert hole 5, in which rugged portions 9, 91 are provided on the sliding surfaces of the seal lips 7, 8.

Abstract: A sealing device for a drive line slip yoke includes a generally resilient seal and a substantially rigid cover that cooperate to provide a fluid-tight seal at the interface between a slip yoke and an axially moving splined shaft. The seal has a mounting portion that includes a shoulder received within a groove defined on an outer surface of the slip yoke. The cover is snapped over the seal and maintained in position by cooperating tabs on the cover and a groove defined on an outer surface of the seal. The seal includes a sealing portion having three axially spaced and radially inwardly extending lips. A middle lip acts as an O-ring that serves as a back-up in the event that one of the other two lips becomes damaged or deteriorates with use. The substantially rigid cover serves to maintain the seal in proper engagement with the end of the slip yoke and protects the seal from damage potentially caused by debris encountered during operation.