Abstract: A viscous damped deflector in accordance with an embodiment of the present disclosure includes at least one sloped spiral rim extending from a lower surface of a top of the viscous damping chamber that rotates with the rotating distributor of the damped deflector, such that viscous fluid in the chamber is pumped to the center of the chamber as the distributor rotates.

Abstract: A sprinkler including a fixed base defining a water inlet and a nozzle, a rotating assembly arranged for rotation relative to the fixed based about a rotation axis and including a water stream director, receiving a pressurized stream of water from the nozzle and directing it in a generally radially outward direction and a rotation speed governing assembly operatively associated with the rotating assembly and operative to intermittently reduce a speed of rotation of the rotating assembly, so as to thereby increase a radial range of the stream, the rotational speed governing assembly including a rotating enclosure rotating together with the rotating assembly and enclosing a viscous material, a static element and a moving element.

Abstract: A sprinkler includes a pop-up deflector plate that is engageable with a brake assembly in an extended position. A brake module is secured to a sprinkler body and includes a rotatable connector coupled with the brake assembly. The pop-up deflector plate is disposed adjacent the nozzle and engages the rotatable connector in the extended position.

Abstract: Provided is a rotary sprinkler that includes a housing, a rotatable irrigation head associated with a first magnet assembly, and a second magnet assembly associated with the housing and fitted with a rotary dampening mechanism. The first magnet assembly and the second magnet assembly are arranged with like poles facing each other so as to generate a repulsion force therebetween.

Abstract: A sprinkler head includes a first housing carrying a center stem having an inlet at an upstream end and an outlet at a downstream end. A second housing is supported within the first housing and encloses a nozzle and a pressure regulator in axially-aligned relationship, defining a flowpath between the inlet and an orifice of the nozzle. The second housing is normally biased to a retracted position but is moveable to an extended position relative to the first housing and to the center stem. A surface of the pressure regulator cooperates with the outlet of the center stem as the second housing moves relative to the first housing to regulate pressure to the nozzle orifice.

Abstract: A sprinkler head nozzle assembly in accordance with an embodiment of the present invention includes a housing including an inlet for pressurize water and an outlet downstream of the inlet, a valve member, operable to extend and reduce an arcuate opening at the outlet of the housing, wherein the size of the arcuate opening indicates the arc of coverage of the sprinkler head nozzle assembly and a rotating distributor, mounted on a central shaft extending through the housing and the valve member, and operable to deflect a flow of water from the arcuate opening out of the nozzle assembly.

Abstract: A sprinkler head includes a nozzle fixed within the sprinkler body, and a wobbler cage including a water deflector plate downstream of the nozzle mounted for rotating and wobbling motion relative to the sprinkler body. In certain embodiments, a viscous brake is fixed within the sprinkler body and includes a shaft rotatable about the longitudinal axis passing through the nozzle. The shaft is eccentrically coupled to the water deflector plate for slowing the rotating and wobbling motion of the wobbler cage and the water deflector plate.

Abstract: A sprinkler including a first portion, a second portion arranged to rotate in reciprocating motion in a plane about a generally vertical axis relative to the first portion, responsive to impingement of a water stream on the second portion, at least a first magnet associated with the first portion and at least a second magnet associated with the second portion, the first and second magnets being magnetized to repel each other when in at least predetermined propinquity during relative rotation thereof in the plane.

Abstract: A jet-breaker device for a jet irrigation apparatus having a supporting frame with a portion for anchoring it to the launch pipe of an irrigation apparatus, jet-breaker means connected to the frame and designed to at least partially project out of the nozzle of the apparatus for interfering with the outlet jet. The jet-breaker means include at least one jet-breaking element which is designed to oscillate with a predetermined frequency in a plane between a position substantially aligned with the nozzle for interfering with the jet and causing partial breaking thereof, and a position misaligned with the nozzle in which it does not interfere with the jet. The jet-breaker means are motorized for controllably adjusting the oscillation of the jet-breaking element and changing the oscillation frequency thereof. A jet irrigation apparatus incorporating the jet-breaker device.

Abstract: A variable arc sprinkler may be set to numerous positions along a continuum to adjust the arcuate span of the sprinkler. The sprinkler includes a nozzle body and a valve sleeve that helically engage each other to define an arcuate slot that may be adjusted at the top of the sprinkler to a desired arcuate span. The sprinkler may include a flow rate adjustment device that may be adjusted by actuation or rotation of an outer wall portion of the sprinkler. Rotation of the outer wall portion may cause a throttle control member to move axially to or away from an inlet, or may cause one or more restrictor elements to open or close, to control the flow rate of the sprinkler.

Abstract: A variable arc sprinkler head or nozzle may be set to numerous positions to adjust the arcuate span of the sprinkler. The nozzle may include an arc adjustment valve having two portions that helically engage each other to define an opening that may be adjusted at the top of the sprinkler to a desired arcuate length. The arcuate length may be adjusted by pressing down and rotating a deflector to directly actuate the valve. The nozzle may also include a radius reduction valve that may be adjusted by actuation of an outer wall of the nozzle. Rotation of the outer wall causes a flow control member to move axially to or away from an inlet.

Abstract: A sprinkler head includes a nozzle fixed within the sprinkler body, and a wobbler cage including a water deflector plate downstream of the nozzle mounted for rotating and wobbling motion relative to the sprinkler body. In certain embodiments, a viscous brake is fixed within the sprinkler body and includes a shaft rotatable about the longitudinal axis passing through the nozzle. The shaft is eccentrically coupled to the water deflector plate for slowing the rotating and wobbling motion of the wobbler cage and the water deflector plate.

Abstract: A rotary sprinkler includes a sprinkler body including a nozzle, a water-deflection plate supported for rotational movement relative to the sprinkler body, the water-deflection plate having one or more grooves configured to cause the water-deflection plate to rotate when impinged upon by a stream emitted from the nozzle; a first brake arranged to slow rotation of the water-deflection plate at all times; and a second brake arranged to further slow rotation of the water-deflection plate as a function of water pressure exerted on the water-deflection plate.

Abstract: A method of controlling rotation of a water distribution plate supported on a shaft and adapted to rotate about an axis defined by the shaft by reason of impingement of a stream emitted from a nozzle on grooves formed in the plate, the method includes: (a) slowing the rotation of the water distribution plate intermittently so as to create intervals of relatively slow and relatively fast rotation and thereby correspondingly increase and decrease, respectively, a radius of throw of the stream or improve the uniformity of water distribution; and (b) continually changing circumferential locations of the intervals about the axis.

Abstract: An improved seal for use in fluid systems such as a water jet system includes an outer seal point that is very close to an inner seal point. By spacing these two seal points very close together, the force on the seal is greatly reduced compared to the prior art. In the disclosed embodiment, the outer seal point is on an angled forward face of the seal that abuts a back-up ring angled face. The inner seal point is between the seal and an internal shaft which rotates relative to a housing.

Abstract: A rotary spray nozzle for spray guns comprises a metallic outer housing and a plastic assembling element wherein the metallic outer housing has a hollow chamber disposed at one side to accommodate the plastic assembling element therein, a water-emitting port disposed at the other side to fluidly connect to the hollow chamber, and a ringed water-blocking seat protruding between the hollow chamber and the water-emitting port. The plastic assembling element, formed a hollow extending there-through, is molded similarly to the hollow chamber and equipped with an internal-threaded portion therein to secure to an external-threaded section defining a water-outlet cylinder of a gun body. The plastic assembling element also has a reverse-stop ring extending at the middle section to restrict the position of a sealing ring mounted to the water-outlet cylinder thereof, achieving anti-leaking and anti-loosing benefits as well as simplifying the structure and manufacturing process of the present invention thereby.

Abstract: A variable arc sprinkler may be set to numerous positions along a continuum to adjust the arcuate span of the sprinkler. The sprinkler includes a nozzle body and a valve sleeve that helically engage each other to define an arcuate slot that may be adjusted at the top of the sprinkler to a desired arcuate span. The sprinkler may include a flow rate adjustment device that may be adjusted by actuation or rotation of an outer wall portion of the sprinkler. Rotation of the outer wall portion may cause a throttle control member to move axially to or away from an inlet, or may cause one or more restrictor elements to open or close, to control the flow rate of the sprinkler.

Abstract: A rotary sprinkler includes: a shaft having a cam, the cam having a plurality of radially outwardly projecting cam lobes; a rotatable water distribution plate adapted to be impinged upon by a stream emitted from a nozzle causing at least the water distribution plate to rotate; a hesitator assembly including a stationary housing having a sealed chamber at least partially filled with a viscous fluid, with at least the cam and the cam lobes located within the chamber; a rotor ring located within the chamber in substantially surrounding relationship to the cam, the rotor ring loosely located within the chamber for rotation and translation, the rotor ring provided with at least two hesitator lobes projecting radially inwardly and movable laterally into and out of a path of rotation of the cam lobes, and a first plurality of radially outwardly projecting teeth selectively engageable with a second greater plurality of teeth provided on an inner wall of the housing; and wherein rotation of water distribution plate is

Abstract: Provided is a rotary sprinkler that includes a housing, a rotatable irrigation head associated with a first magnet assembly, and a second magnet assembly associated with the housing and fitted with a rotary dampening mechanism. The first magnet assembly and the second magnet assembly are arranged with like poles facing each other so as to generate a repulsion force therebetween.

Abstract: A method for water jet stripping and recontouring of a coated article of manufacture is provided. The method includes dimensionally scanning the coated article and establishing a three-dimensional model for the coated article. The method further includes establishing a set of reduced dimensional profiles for recontouring and then analyzing whether the reduced profiles are satisfactory for subsequent operation. A jet spraying program is established for removal of the coating and the surface base material to each predetermined reduced dimensional profile.

Abstract: A self-governing spray apparatus for irrigation or cleaning purposes is provided. A spray nozzle at the end of a moment arm and substantially perpendicular to an axis of rotation creates a reaction torque to distribute a spray by spinning. A hinged member thrust into the spray pattern a centrifugal force caused by the spin deflects a portion of the spray and results in a braking action. An equilibrium angular speed is thereby reached by a self-correcting mechanism.

Abstract: A dual-mode sprinkler includes a nozzle arranged to supply a stream to a rotatable water-distribution plate. The sprinkler can be adjusted between free-spinning and retarded or braked rotation, enabling multi-use applications for the sprinkler.

Abstract: A water distribution plate and diffuser plate assembly for distributing a stream emitted from a sprinkler nozzle comprising: a shaft having one end attached to a sprinkler component and an opposite end supporting first and second plates in axially spaced relationship for rotation about the shaft independent of one another; the first plate located adjacent the nozzle and formed with at least one water distribution groove shaped and arranged to divide a primary stream emitted from the nozzle into a plurality of secondary streams, and the second plate located downstream of the first plate and formed with at least one diffuser element arranged to be struck by at least some of the secondary streams exiting the first plate, and wherein speed of rotation of the first and second plates is braked.

Abstract: A dual-mode sprinkler includes a nozzle arranged to supply a stream to a rotatable water-distribution plate. The sprinkler can be adjusted between free-spinning and retarded or braked rotation, enabling multi-use applications for the sprinkler.

Abstract: A water distribution plate and diffuser plate assembly for distributing a stream emitted from a sprinkler nozzle includes: a nonrotatable shaft having one end attached to a sprinkler component and an opposite end supporting first and second plates in axially spaced relationship for rotation about the shaft independent of one another. The first plate is axially adjacent the nozzle and formed with plural water distribution grooves shaped and arranged to divide a single primary stream emitted from the nozzle into a plurality of secondary streams. The second plate is downstream of the first plate and formed with plural diffuser elements arranged to be struck by at least some of the secondary streams exiting the first plate. The speed of rotation of one or both plates is slowed by viscous damping.

Abstract: A rotary sprinkler comprising a sprinkler body supporting a nozzle body and a water distribution plate supported on a shaft downstream of said nozzle body, said water distribution plate provided with a plurality of grooves shaped to redirect a stream emitted from said nozzle body and to cause the water distribution plate to rotate when struck by the stream; a stream deflector supported within said sprinkler body and surrounding said nozzle body; wherein said nozzle body and said stream deflector cooperate to produce a substantially rectangular wetted pattern area.

Abstract: An improved seal for use in fluid systems such as a water jet system includes an outer seal point that is very close to an inner seal point. By spacing these two seal points very close together, the force on the seal is greatly reduced compared to the prior art. In the disclosed embodiment, the outer seal point is on an angled forward face of the seal that abuts a back-up ring angled face. The inner seal point is between the seal and an internal shaft which rotates relative to a housing.

Abstract: A turbine for a sprinkler is disclosed for self-governing its rotational velocity. As a rate of fluid through the sprinkler increases, particularly when air is used to flush the sprinkler system, a portion of the turbine shifts outwardly so as to decrease alignment of vanes located thereon with directed water streams for controlling the rotation of the turbine.

Abstract: The cleaning nozzle according to the invention having a nozzle body (100) and a nozzle head (104) arranged on a shaft (106) rotatably seated on said nozzle body, and having a cavity (107), which extends in axial direction in said nozzle body (100) and which is connected with a pressurized water supply (102), by means of which cavity pressurized water supplied via the pressurized water supply (102) is guided to the nozzle head (104) and is discharged to the outside in said nozzle head (104) by at least one nozzle orifice (118), is formed especially by a friction brake comprising at least two disc elements (108, 110) that are in mechanical contact one with the other in the axial direction for restricting the rotational motion of the shaft (106).

Abstract: A revolving sprinkler comprises a rotatable turret assembly revolving around a rotation axis and formed with mouthpiece(s) suited to sprinkle liquid under pressure. The revolving sprinkler accommodates exchangeable mouthpieces with different throughputs-nozzle to rotation axis distance relationships, without changing a rotation velocity of the turret assembly.

Abstract: A speed limiting mechanisms for turbine-driven fluid distribution apparatus usable with compressible fluid such as compressed air and incompressible fluid such as water. In one form, a flow restrictor is located in the turbine discharge flow path, with the turbine discharge port area selected in relation to the turbine inlet port area according to the desired turbine speed with compressed air. In another form, the incoming fluid flows downstream along the surface of the turbine stator, and is then diverted to enter the rotor chamber in the proper direction. A bleed area on the stator which permits a portion of a compressible fluid which has expanded as it flows along the stator surface to flow to bypass the turbine rotor.

Abstract: A sprinkler apparatus 10 for providing more even coverage of a sprinkled area with water which is achieved by a different speed of rotation of a water deflector 13 relative to a water diffuser 12 in a wobbling sprinkler head. A diffuser head 11 is rotatably attached to a base 16 and has a water diffuser 12 for diffusing water passing therethrough. A water deflector 13 is rotatably attached to the rotatable diffuser head 11 for directing water emitting from the nozzle 21 through the water diffuser 12. A viscous fluid brake 15 couples the water deflector 13 to the water diffuser 12 to vary the speed of rotation of the water diffuser 12 relative to the water deflector 13 to obtain a more even coverage of the area being sprinkled.

Abstract: An improved seal for use in fluid systems such as a water jet system includes an outer seal point that is very close to an inner seal point. By spacing these two seal points very close together, the force on the seal is greatly reduced compared to the prior art. In the disclosed embodiment, the outer seal point is on an angled forward face of the seal that abuts a back-up ring angled face. The inner seal point is between the seal and an internal shaft which rotates relative to a housing.

Abstract: A water distribution plate and diffuser plate assembly for distributing a stream emitted from a sprinkler nozzle includes: a nonrotatable shaft having one end attached to a sprinkler component and an opposite end supporting first and second plates in axially spaced relationship for rotation about the shaft independent of one another. The first plate is axially adjacent the nozzle and formed with plural water distribution grooves shaped and arranged to divide a single primary stream emitted from the nozzle into a plurality of secondary streams. The second plate is downstream of the first plate and formed with plural diffuser elements arranged to be struck by at least some of the secondary streams exiting the first plate. The speed of rotation of one or both plates is slowed by viscous damping.

Abstract: A water distribution plate and diffuser plate assembly for distributing a stream emitted from a sprinkler nozzle comprising: a shaft having one end attached to a sprinkler component and an opposite end supporting first and second plates in axially spaced relationship for rotation about the shaft independent of one another; the first plate located adjacent the nozzle and formed with at least one water distribution groove shaped and arranged to divide a primary stream emitted from the nozzle into a plurality of secondary streams, and the second plate located downstream of the first plate and formed with at least one diffuser element arranged to be struck by at least some of the secondary streams exiting the first plate, and wherein speed of rotation of the first and second plates is braked.

Abstract: The present invention provides a turbine with dual sets of fins and a stator assembly for directing water onto both sets of fins. The water flow directed to the first set of fins generates slightly more force than the water flow directed to the second set of fins. In this manner, the opposing forces generated by the water flow maintain a more uniform and constant speed of the turbine.

Abstract: An improved rotating stream sprinkler of the type having a rotatable spray head with an offset nozzle port through which a water stream is projected outwardly, resulting in a reaction force for rotatably driving the spray head to sweep the water stream over a surrounding terrain area. The spray head is rotatably mounted on a body adapted for connection to a pressurized water supply, with interengaging bearing components providing predetermined friction brake torque resisting spray head rotation. By appropriately designing the nozzle port area and offset geometry, drive torque and brake torque is maintained at a substantially constant ratio for relatively slow and substantially constant spray head rotational speed over a range of normal water supply operating pressures. A downthrust spring retains the bearing components in engagement when the water supply is turned off, but does not contribute to friction brake torque when the water supply is turned on.

Abstract: An embodiment of an internal self-rotating fluid nozzle includes a rotor rotatably moveable within a nozzle body cavity. The rotor may include a jewel holder that carries at least one jewel member and spins against a rotor seat disposed near the front of the cavity. The rotor seat may be floating. At least one fluid drive passageway may be disposed within, and oriented angularly relative to the central axis of, the cavity. A fluid flow director may be included, extend around the inner circumference of the cavity and include a protruding portion that directs fluid into a forward portion of the cavity.

Abstract: A rotary jetting tool including a pressure-balanced rotor, which is achieved using a vented volume. Axial movement of the rotor relative to the housing caused by pressure imbalances acting on the rotor selectively uncovers or opens a vent that places the volume in fluid communication with an ambient volume, enabling the rotor to achieve a pressure balanced condition. A plurality of radial clearance seals between the rotor and the housing are used to provide hydrodynamic bearings to reduce friction between the rotor and housing. The diameters of the seals are manipulated to facilitate pressure balancing of the rotor. In one embodiment, the rotor includes a centrifugal brake configured to control a maximum rotational speed of the rotor. Pressurized fluid is introduced into the rotor in an axial direction, enabling a relatively large upstream settling chamber to be incorporated into the rotor, thereby reducing inlet turbulence and improving jet quality.

Abstract: A sprinkler head having a deformable member forming a collar is disclosed. The deformable member allows the sprinkler head to resist entry of foreign grit or matter within the sprinkler head, and allows the sprinkler head to eject or force out foreign matter from within the sprinkler head. The sprinkler head may be a spinning sprinkler head including a vane deflector, and the spinning sprinkler head may include a portion that shifts in response to being struck by water such that a braking mechanism is engaged in response to the force of the water. When water flow ceases, the spinning head may shift towards the deformable member so that a portion of the spinning head is received within the deformable member to restrict foreign matter from entering the sprinkler head.

Abstract: A sprinkler head includes a base; an arc adjustment ring; a nozzle and a stream deflector supported by an elongated stem carried by the base, the nozzle and the stream deflector cooperating to define an adjustable nozzle orifice; a water distribution plate secured to a shaft and located downstream of the nozzle; and a drive train operatively connected between the arc adjustment ring and the nozzle to rotate the nozzle relative to the stream deflector to adjust the nozzle orifice between limit positions. The stem is rotatable within the base upon over-rotation of the arc adjustment ring beyond the limit positions. The sprinkler head also incorporates a throttle control member movable axially relative to a flow restriction seat, to thereby adjust flow rate through the nozzle, and means for permitting rotation of the throttle control member with the shaft upon over-rotation of the shaft.

Abstract: A rotor nozzle includes a nozzle housing having an inlet opening at one end and an outlet opening at another end and has a rotor which is arranged in a turbulence chamber and which is provided at its front end facing the outlet opening. A nozzle is supported in a cup bearing and has an inflow opening. A bypass device changes a radial or a tangential component of the liquid flowing into the turbulence chamber, which sets the rotor into rotation. A control surface is provided in the turbulence chamber. A restoring device is provided which is active between the front end of the rotor and the rear rotor end, wherein as the rotor rotary speed increases, the inclination of the rotor increases against the action of a restoration force of the restoring device and the restoring device reduces the rotor inclination as the rotor rotary speed decreases.

Abstract: The present invention is directed to a sprinkler apparatus and related methods for the distribution of fluid. The invention preferably includes a nozzle rotatably driven by a pressurized flow of fluid along a fluid path. The invention preferably includes a housing separating a magnetic drag coupling assembly from the fluid path. The coupling assembly preferably includes spaced apart magnets configured to exert an attractive force on each other to rotate one magnet in response to the rotation of the other magnet, and a resistive/drag force to oppose the continuous rotation of the nozzle. Pressure offsetting structures minimize or even neutralize the upward/downward forces that the flowing fluid otherwise would exert on the rotating shaft assembly.

Abstract: A rotary sprinkler system for both above-the ground and pop-up rotary sprinkler systems that controls the rate of nozzle rotation is disclosed. To maintain a relatively constant and controlled nozzle rotation, one or more chamfered spokes are included on the turbine of the sprinkler system. This turbine configuration together with a stator assembly that regulates fluid flow to the turbine control nozzle rotation despite variations in fluid flow. In particular, the chamfered spokes counteract the spin of the turbine in direct relation to the amount of water that bypasses the driving blades of the turbine.

Abstract: A nozzle for use in cleaning applications is provided. The nozzle has a rotatably supported nozzle body, on which one or more nozzle orifices are provided. The nozzle housing itself serves as the rotary drive, which is carried along by a fluid led into the housing with torque. In order to stabilize the drive action, at least one braking device is provided on the nozzle which generates a braking torque by fluid action, preferably through the recoil on a nozzle opening.

Abstract: A sprinkler head includes a base; an elongated stem having an inlet supported within the base; a nozzle and a stream deflector supported within the stem, the nozzle and stream deflector cooperating to define an arcuate orifice; a water distribution plate supported on one end of a shaft extending upwardly from the base, the water distribution plate located in axially spaced relationship to the nozzle and adapted to be impinged by a stream emitted from the nozzle. An externally threaded sleeve is fixed to an opposite end of the shaft; and an elastomeric throttle control member constructed with a smooth through-bore is engaged over the externally threaded sleeve to self-tap along the previously smooth bore. The throttle member is prevented from rotating such that rotation of the shaft causes the throttle control member to move axially relative to a flow restriction portion in the inlet, to thereby adjust flow rate through the stem and the nozzle.

Abstract: A rotary sprinkler system for both above-the ground and pop-up rotary sprinkler systems that controls the rate of nozzle rotation is disclosed. To maintain a relatively constant and controlled nozzle rotation, one or more chamfered spokes are included on the turbine of the sprinkler system. This turbine configuration together with a stator assembly that regulates fluid flow to the turbine control nozzle rotation despite variations in fluid flow. In particular, the chamfered spokes counteract the spin of the turbine in direct relation to the amount of water that bypasses the driving blades of the turbine.

Abstract: A rotating stream sprinkler including a rotor plate supported on one end of a shaft for rotation, in an operative mode, relative to the shaft; a nozzle located along the shaft upstream of the rotor plate; the rotor plate formed with a chamber and one end of the shaft has a stator fixed thereto within the chamber, the fluid chamber at partially filled with a viscous fluid; and wherein the chamber is at least partially closed at an upper end thereof by a rotor cap plate; and further wherein an underside of the rotor cap plate is provided with a first plurality of teeth and an upper surface of the stator is provided with a second plurality of mating teeth adapted to engage the first plurality of teeth to enable rotation of the rotor plate with the shaft in the adjustment mode.

Abstract: A rotating stream sprinkler including a rotor plate supported on one end of a shaft for rotation, in an operative mode, relative to the shaft; a nozzle located along the shaft upstream of the rotor plate; the rotor plate formed with a chamber and one end of the shaft has a stator fixed thereto within the chamber, the fluid chamber at least partially filled with a viscous fluid; and wherein the chamber is at least partially closed at an upper end thereof by a rotor cap plate; and further wherein an underside of the rotor cap plate is provided with a first plurality of teeth and an upper surface of the stator is provided with a second plurality of mating teeth adapted to engage the first plurality of teeth to enable rotation of the rotor plate with the shaft in the adjustment mode.

Abstract: A rotating stream sprinkler including a rotor plate supported on one end of a shaft for rotation, in an operative mode, relative to the shaft; a nozzle located along the shaft upstream of the rotor plate; the rotor plate formed with a chamber and one end of the shaft has a stator fixed thereto within the chamber, the fluid chamber at least partially filled with a viscous fluid; and wherein the chamber is at least partially closed at an upper end thereof by a rotor cap plate; and further wherein an underside of the rotor cap plate is provided with a first plurality of teeth and an upper surface of the stator is provided with a second plurality of mating teeth adapted to engage the first plurality of teeth to enable rotation of the rotor plate with the shaft in the adjustment mode.