Abstract: Nozzle system for a powder blasting device including a first nozzle element for transporting a powder-gas mixture stream along a transporting direction and a second nozzle element, where the second nozzle element surrounds the first nozzle element such that at least one channel is formed between the first nozzle element and the second nozzle element, where the channel is provided for transporting a liquid stream, where the first nozzle element and the second nozzle element are arranged such that in operation the powder-gas-mixture stream ejected by the first nozzle element is encased by the liquid stream ejected by the channel for forming an output stream of the nozzle system, where the first nozzle element has an acceleration part having a first cross section and a spreading part having a second cross section, where the spreading part is arranged downstream of the acceleration part.

Abstract: To uniformly bring an abrasive into contact with a workpiece and to achieve desired surface roughness. A polishing tool sliding on a narrow part of the workpiece includes an abrasive retaining layer configured to allow an abrasive to be retained on a surface, and an elastic layer that is stacked on the abrasive retaining layer and is configured to press the abrasive retained in the abrasive retaining layer against the workpiece. The elastic layer is preferably elastically deformable over a sliding stroke of the polishing tool, and a driving unit that causes the polishing tool to slide on the workpiece is preferably connected to the polishing tool.

Abstract: The invention discloses an oral care device (100) comprising a head portion (102) having a protuberance (104) for engaging an interproximal region within an oral cavity. The oral care device (100) also comprises at least one sensor (108) for acquiring motion data for the oral care device, and a processor (110). The processor is configured to determine when the protuberance of the head portion engages an interproximal region in the oral cavity; and determine, based on motion data acquired by the at least one sensor as the protuberance moves between interproximal regions, a position of the head portion of the oral care device in the oral cavity. An oral care system and a method of determining a position of an oral care device in an oral cavity are also disclosed.

Abstract: A handle system for supporting a tool defining a tool axis during the performance of dental procedures comprises a handle defining a handle axis, a rotation sleeve, a head assembly and a gear set comprising first and second gear portions. The rotation sleeve supports the first gear portion. The head assembly supports the second gear portion. The handle supports the rotation sleeve for rotation relative to the handle. The handle supports the head assembly such that the first gear portion engages the second gear portion. With the head assembly supported by the handle, the head assembly engages the tool to support the tool such that the tool axis extends at a first angle relative to the handle axis and rotation of the rotation sleeve relative to the handle causes axial rotation of the tool about the tool axis.

Abstract: A powder delivery nozzle (12) for a personal care appliance (10) comprises a body (28), guidance tip (38), powder chamber (50), and flexible membrane (56). The body (28) includes an air-liquid channel (30) for delivery of air and/or liquid from a proximal end to a distal end thereof. The guidance tip (38), located at the distal end of the body (28), includes an orifice (40) coupled to the air-liquid channel (30) and is configured to expel a pulse of air and/or liquid. The powder chamber (50) is configured for storing a powder (52) and having an air intake port (42) and a powder outlet port (44). The flexible membrane (56) is disposed between the powder chamber (50) and the air-liquid channel (30). Responsive to delivery of a pulse of air and/or liquid via the air-liquid channel (30), a pulse of pressure is applied to the flexible membrane (56) for actuating a release of powder expelled from the powder chamber (50) via the powder outlet port (44). A method and personal care appliance are also disclosed.

Abstract: A method and an apparatus for detecting infrasound that determines the direction and position of an infrasound source. The detection method includes a container exposed to an infrasound source and partially filled with a mist (N) which is embedded in a carrier medium so that the resulting pressure change over time results in the formation of a directed front at the mist surface that can be optically detected.

Abstract: A handle extension for a belt sander comprising a hollow member having a front side, a rear side, a first side, a second side, and a third side, wherein the front side, rear side, and first side have a cutout in a predetermined location and size and the third side has an opening in a predetermined location and a predetermined size, a handle of a predetermined length and sized to be received by the opening on the third side of the hollow attachment member, and a securing mechanism attached to at least the first side and the second side of the hollow member.

Abstract: A prophylaxis angle that is configured to be attached to and operated by a powered dental handpiece. The prophylaxis angle includes a cup having a first end and a second end. The first end is couplable to the dental handpiece and at least one projection is at the second end of the cup.

Abstract: Provided is prophylaxis cup for dentistry, comprising a first section storing a first medium, a second section storing a second medium, and one or more channels between the first section and the second section, wherein the first section, the second section and the one or more channels are adapted to allow the first medium and the second medium to be mixed, in response to a rotational movement of the prophylaxis cup. Provided also is a method for using prophylaxis cup in which the prophylaxis cup is positioned on a patient's tooth. A control is triggered to rotate the prophylaxis cup to cause a first medium stored in a first section of the prophylaxis cup to be mixed with a second medium stored in a second section of the prophylaxis cup. Provided further is a prophylaxis angle for dentistry, comprising a hand-piece, with the prophylaxis cup coupled to the hand-piece.

Abstract: Disclosed are embodiments of a dental prophylaxis angle. One dental prophylaxis angle includes a body having a neck that defines a first axial bore and a head that defines a second axial bore, the first and second axial bores communicating at an intersection and being angularly-offset from each other, a drive gear rotatably mounted in the first axial bore and having a drive gear head and a locking flange axially-offset from the drive gear head, an annular locking groove being defined between the drive gear head and the locking flange, a driven gear rotatably mounted in the second axial bore and operatively coupled to the drive gear, and a gear retainer having an annular body configured to extend about an outer surface of the head, a heel extending from the annular body, an arm extending from the heel, and a wedge extending from the arm.

Abstract: A prophy angle is provided that includes a housing with a prophy cup at the distal end, a first drive mechanism positioned within the housing and including a drive shaft for delivering mechanical energy to the prophy cup, a chamber enclosed within the housing to store paste in a controlled releasable manner, and an independent second drive mechanism within the housing to control the delivery of paste from the chamber to the prophy cup in a manner to reduce friction in paste delivery and to avoid contact of the paste with the first drive mechanism and its associated gears.

Abstract: A device for quickly stopping a medical or dental drilling tool includes a drilling tool having a body extending between a connection end and a working end and having a longitudinal extension along a longitudinal axis of the drilling tool. The drilling tool has a hollow outer shell in which a probe is held that can be moved along the longitudinal axis so that a part of the probe can be moved out of the shell through an opening. The probe is designed as an elongated pin, and its first end facing the connection end is held in the interior of the shell. An electromagnetic sensor for detecting relative movement between the shell and the probe is arranged along the longitudinal extension of the body. The drilling tool has a channel for a treatment fluid extending along the longitudinal axis.

Abstract: A dental handpiece to which various tools forming a tool set can be coupled, and more precisely a handpiece coupling, which can be driven by a drive in the dental handpiece at least for an axial oscillating motion The coupling is constituted for a connection of the tools by insertion and securing, and more precisely with a conically tapering opening, into which an adapted coupling section of the tools that tapers in the shape of a truncated cone can be introduced and secured in a suitable manner.

Abstract: A prophy angle is provided that includes a paste-dispensing assembly that includes an actuator at the proximal end of the housing, a push rod linked to the actuator and supporting a plunger on the push rod is provided, where the push rod is supported by the housing in a biased manner to permit longitudinal movement within the housing in a reciprocating manner as actuated by the actuator, to dispense a controlled quantity of paste out of the prophy angle.

Abstract: The present invention provides a dental prophylaxis angle that includes a housing, a rotor disposed in the housing, and a drive shaft driving the rotor. The drive shaft and the rotor operate together with a sidewall of the housing against a common surface of the rotor to prevent removal of the rotor from the housing in a direction along an axis of rotation of the rotor.

Abstract: A prophy cup has an outer surface with dimples formed therein. The dimples increase the turbulent flow in a boundary layer proximate to the surface. The increased turbulent flow reduces the separation of fluid (a slurry of saliva, blood and pumice) at the boundary layer to minimize the quantity of fluid ejected from the surface. A dental handpiece housing is configured to split longitudinally so that a wiper is positioned proximate to the outer surface of the prophy cup. The wiper removes slurry as the prophy cup rotates during a dental cleaning procedure to further reduce the quantity of fluid ejected from the surface during the procedure.

Abstract: The present invention is directed to dental prophylaxis devices that improve portability, maneuverability and aid in retaining clean conditions for use on dental patients, particularly to dental handpieces. The present invention is also directed prophylaxis or prophy angles for use with such handpieces. In general, a dental prophylaxis device includes a handpiece and a prophy angle which includes a driven shaft and a prophy cup attached for rotation thereto. The handpiece generally includes a body which houses a rotational source coupled to an output shaft which couples to the driven shaft in the prophy angle via angled gear interfaces on the output shaft and the driven shaft.

Abstract: A cordless dental handpiece, a system including a cordless dental handpiece, and a method of connecting a cordless dental handpiece are disclosed. The cordless dental handpiece includes a first module and a second module. The second module is configured to detachably engage the first module. The second module includes a battery compartment.

Abstract: A prophy angle is provided that includes a housing with a prophy cup at the distal end, a first drive mechanism positioned within the housing and including a drive shaft for delivering mechanical energy to the prophy cup, a chamber enclosed within the housing to store paste in a controlled releasable manner, and an independent second drive mechanism within the housing to control the delivery of paste from the chamber to the prophy cup in a manner to reduce friction in paste delivery and to avoid contact of the paste with the first drive mechanism and its associated gears.

Abstract: Disclosed are embodiments of a dental prophylaxis angle. One dental prophylaxis angle includes a body having a neck that defines a first axial bore and a head that defines a second axial bore, the first and second axial bores communicating at an intersection and being angularly-offset from each other, a drive gear rotatably mounted in the first axial bore and having a drive gear head and a locking flange axially-offset from the drive gear head, an annular locking groove being defined between the drive gear head and the locking flange, a driven gear rotatably mounted in the second axial bore and operatively coupled to the drive gear, and a gear retainer having an annular body configured to extend about an outer surface of the head, a heel extending from the annular body, an arm extending from the heel, and a wedge extending from the arm.

Abstract: A system for reconditioning a dental implant in situ comprising a buffer member, a drive member, abrasive material, and a sleeve member. The sleeve member moves between first and second positions relative to the buffer member. The buffer member is in an open configuration when the sleeve member is in the first position. The sleeve member holds the buffer member in a closed configuration when the sleeve member is in the second position. The buffer member is rotated such that the plurality of fingers of the buffer member cause the abrasive material to remove at least a portion of the texture layer on the textured portion of implant outer surface of the second implant portion.

Abstract: A system for enhanced sealing against intrusion of moisture and other contaminants for medical/dental handpieces having rotating or other moving elements driven by a motor within the handpiece. The enhanced sealing includes tandem seals on stepped diameters to provide additional flow pathway impediments. The tandem seals preferably include spring seals that are positioned in opposite directions to provide enhanced sealing against pressures in two different directions that occur during the pressurization and vacuum cycles of an autoclaving process. Additional enhancements include the use of annular sealing rings with x-shaped cross sections.

Abstract: A dental tool including a dental prophy angle and a dental prophy angle adapter is provided. A dental prophy angle includes a housing and a rotor. The dental prophy angle adapter can include a drive shaft with a tip. The drive shaft of the adapter can be coupled to a gear at the same end of the tip with the rotor of the prophy angle being configured to receive the tip. Further, a slidable sleeve can extend over a portion of the drift shaft so that the slidable sleeve becomes automatically retracted upon engaging a shoulder of the housing resulting in the gear of the drive shaft being positioned beyond the end of the slidable sleeve.

Abstract: Air/gas driven prophylaxis preparation dispensing system coupled to a dental hand piece, the system comprising a hand piece connector receiving an air/gas pressure and adjustably diverting a portion of the air/gas pressure to drive a piston toward an open delivery end of a container containing a prophylaxis preparation for dispensing the prophylaxis preparation out of an open delivery end of the container, through a passageway surmounting a disposable prophy angle supporting a gear train, through a portion of the gear train supporting a prophy cup, through an opening in the prophy cup to an internal cavity of the prophy cup while simultaneously driving an air/gas driven rotational member of the dental hand piece coupled to the gear train with the remaining portion of the air/gas pressure to impart rotation of the prophy cup while simultaneously dispensing the prophylaxis preparation into the internal cavity thereof.

Abstract: A variable speed tooth polishing system including a tooth polisher with multiple polishing head capability, in order to provide therapeutic treatment to gums and guard against undesired exposure to potentially hazardous fluids present during routine dental cleansing and polishing, such as polishing paste, tooth paste, blood, and salivary excretions. A splatter guard comprising a plurality of serrations are cut through a wall of the splatter guard, wherein each of the serrations starting at an open end of the splatter guard and continuing into a length of said splatter guard forming a series of flexible splatter guard fingers about the open end of the splatter guard. The splatter guard is affixed to a polishing end of a prophy angle encompassing a polisher, wherein the splatter guard is provided to entrap any loose material resulting from a polishing process within the splatter guard.

Abstract: A dental system comprises a dental prophy angle and an adapter. The prophy angle includes a housing and a latch mechanism. The adapter is configured to drive the prophy angle. The latch mechanism includes a lever and a first latch element, which are both defined by a pair of opposing U-shaped slots within the housing, such that free ends of one of the pair of opposing U-shaped slots are disposed between free ends of the other of the pair of opposing U-shaped slots. The adapter includes a nose having a second latch element and a depression proximate to the second latch element. Upon the first latch element mating with the second latch element, the depression is positioned adjacent the lever.

Abstract: The present invention provides a dental prophylaxis angle that includes a housing, a rotor disposed in the housing, and a drive shaft driving the rotor. The drive shaft and the rotor operate together with a sidewall of the housing against a common surface of the rotor to prevent removal of the rotor from the housing in a direction along an axis of rotation of the rotor.

Abstract: The present invention relates to a dental implant cleaning apparatus. A dental implant cleaning apparatus according to the present invention includes: a wire bundle formed of flexible materials; a tube enclosing the wire bundle; and a driver connected to the wire bundle, to drive the wire bundle. Accordingly, according to the present invention, a clean dental implant may be maintained after the dental implant is placed, and a lifespan of an implant may be extended by mechanically removing chemical and biological infections (pollutants) from a surface of the implant when the implant is infected.

Abstract: The combination rotating dental cleaning brush and paste device. The device includes a housing having a rotating shaft therethrough. A compressible tube has two opposed ends, a first end which is rotated by the shaft and a second end having an opening therethrough. A brush is integral with, connected to, and rotated by the second end of the tube. Compression of the compressible tube forces dental paste inside of the tube out of an opening in the second end of the tube and onto the brush.

Abstract: The present invention provides a dental prophylaxis angle that includes a housing, a drive shaft, and a rotor. The housing may define a first bore and a second bore in communication with the first bore. The drive shaft is positionable in the first bore and may include a distal bearing surface. The rotor is positionable in the second bore and can be driven by the drive shaft. Further, the rotor rotates about a first axis. The second bore can further include a side surface, a plane perpendicular to the first axis that intersects both the side surface and the distal bearing surface. The drive shaft and the side surface of the second bore can operate together, against a common surface of the rotor, to prevent removal of the rotor from the second bore in a direction along the first axis.

Abstract: This patent relates to a machine that automatically assembles, inspects, and packages disposable prophylaxis angles. The machine includes a movable table including a plurality of fixtures on which angle components are assembled and the assembled angles are inspected. The movable table is surrounded by a number of stations, each of which performs a different operation of the assembly and inspection procedure. Feeders automatically supply the angle components to their respective stations for assembly. Angles that are incorrectly assembled are automatically rejected. Properly assembled angles are automatically sealed in individual bags. Individually bagged angles are counted into batches by the machine and automatically sealed into cartons.

Abstract: A prophy device incorporating a shaft and one or more corrugated members eliminates the need for plastic gears. The corrugated members effectively transfer rotational energy from a shaft to an applicator. In another version, a flexible paste chamber contains polish within a housing of the device. A difference between a rotational speed at a front of the paste chamber and rear of the chamber causes the flexible chamber to contract on itself thereby automatically forcing polish from the chamber and into a polish applicator. A rod extending through a paste chamber includes openings for contents to exit. The rod has one end in contact with a drive disk and a second end in contact with a front disk such that the ends of the rod are maintained substantially in place by the drive disk and front disk, respectively, but remain rotatably independent relative to the drive disk and front disk.

Abstract: An adjustable angle adapter for a prophy angle comprises a nose, a rotating member, a body, a shaft, and a multi-axis rotation joint. The nose is configured to receive a portion of a prophy angle. The rotating member is positioned within the nose. The body is adjustably connected to the nose. The shaft is positioned within the body. The multi-axis rotation joint connects the shaft to the rotating member. The nose is rotatable relative to the body into at least a first configuration and a second configuration.

Abstract: According to one embodiment, an apparatus for removing enamel from a person's tooth includes a blade portion and a handle portion. The blade portion includes an abrasive surface adapted to remove enamel from the tooth in response to reciprocating movement of the abrasive surface against the enamel. The handle portion is coupled to the blade portion and includes first and second regions, the first region is proximal and the second region is distal to the blade portion. The first region includes a substantially solid cross-section with a substantially circular perimeter. The second region includes a substantially solid cross-section with at least a substantially semi-circular perimeter, the solid cross-section defining a notched region. The apparatus is adapted to be inserted via a pressure fit into a corresponding opening in a driver mechanism adapted to drive reciprocating movement of the blade portion and the abrasive surface.

Abstract: A dental prophy angle includes a housing and a rotor. The housing defines a first bore and a second bore in communication with the first bore, and rotor is disposed within the second bore. The rotor includes a gearing system, and rotor includes a lock having a lock channel configured to receive a tip of a drive shaft. The housing includes a lock receiver for receiving the lock receiver permits rotation of the lock within the lock receiver and restrains linear movement of the lock in a direction substantially parallel to a rotational axis of the rotor.

Abstract: Provided is a dental handpiece adapter connection system, dental handpiece adapter connection method, and a dental handpiece adapter. The dental handpiece adapter includes a first portion configured to engage a dental device having a first geometry and a second portion configured to engage a dental handpiece having a second geometry. The first portion being engaged with the adapter and the second portion being engaged with the adapter permits the dental handpiece to rotate a rotatable portion of the dental device.

Abstract: The combination rotating dental cleaning brush and paste device. The device includes a housing having a rotating shaft therethrough. A compressible tube has two opposed ends, a first end which is rotated by the shaft and a second end having an opening therethrough. A brush is integral with, connected to, and rotated by the second end of the tube. Compression of the compressible tube forces dental paste inside of the tube out of an opening in the second end of the tube and onto the brush.

Abstract: Provided is a dental handpiece adapter connection system, dental handpiece adapter connection method, and a dental handpiece adapter. The dental handpiece adapter includes a first portion configured to engage a dental device having a first geometry and a second portion configured to engage a dental handpiece having a second geometry. The first portion being engaged with the adapter and the second portion being engaged with the adapter permits the dental handpiece to rotate a rotatable portion of the dental device.

Abstract: A variable speed tooth polishing system including a tooth polisher with multiple polishing head capability, in order to provide therapeutic treatment to gums and guard against undesired exposure to potentially hazardous fluids present during routine dental cleansing and polishing, such as polishing paste, tooth paste, blood, and salivary excretions.

Abstract: An ultrasonic tool is disclosed with a handpiece (300, 500, 806) containing coils (304A-304D; 504A-504D; 804A-804B) that produce an electromagnetic field that vibrates a magnetic rod (102, 702A, 702B, 820) of a moveable pin transducer (MPT) 100 disposed within the handpiece. Ultrasonic vibrations are produced when the coils are selectively powered by an ultrasonic signal generator, which can include a stepper motor control apparatus (1300, 1400). A tip 106 can be removably attached to an MPT 100. A channel (708A, 708B) in the magnetic rod (700A, 700B) can allow fluidic communication with a handpiece fluid supply channel (310, 510). A method of vibrating a tool can include controllably energizing at least one electromagnetic coil contained within a handpiece to vibrate a magnetic rod and an attached tip. The method can include varying the energy to at least one of the electromagnetic coils with a stepper motor control apparatus.

Abstract: According to one embodiment, an apparatus for removing enamel from a person's tooth includes a blade portion and a handle portion. The blade portion includes an abrasive surface adapted to remove enamel from the tooth in response to reciprocating movement of the abrasive surface against the enamel of the tooth. The handle portion is coupled to the blade portion, has a substantially solid cross-section, and is adapted to be inserted into a corresponding opening in a driver mechanism that is adapted to drive reciprocating movement of the blade portion to provide the reciprocating movement of the abrasive surface.

Abstract: A dental prophylaxis angle and handpiece assembly for cleaning and polishing teeth is provided. The dental prophylaxis angle is removably attached to the dental handpiece by an interlocking mechanism that includes extension locking tabs, a locking annular member, and an interlocking drive member in the handpiece. The prophy angle is securely snap-fitted onto the handpiece and locked in place so that it has minimal lateral movement. After the prophy angle has been used to treat a patient, it can be removed easily from the handpiece and disposed thereof.

Abstract: An improved low cost dental hygiene handpiece with high reliability coupling mechanism for disposable prophy angles and doriot type dental tool heads. The disposable prophy angles and dental tool heads are designed with non circular input shaft endings, engaging a matching non circular power output driver of the handpiece. The invention prevents the application of any axial force on the drive train and the driving motor both during the installation of the prophy angle and during the operation of the device, thereby eliminating the need for any axial trust bearings in the handpiece.

Abstract: A prophy device incorporating a shaft and one or more corrugated members which eliminate the need for plastic gears of the prior art is disclosed. The corrugated members effectively transfer rotational energy from a shaft to an applicator. In another version, a flexible paste chamber contains polish within a housing of the device. A difference between a rotational speed at a front of the paste chamber and rear of the paste chamber causes the flexible chamber to contract on itself thereby automatically forcing polish from the chamber and into a polish applicator. A user dictates the amount of polish dispensed by controlling the rotational speed at the front of the paste chamber by pressing the polish applicator against the teeth of a patient. As the speed differential increases, the amount of polish dispensed increases as well.

Abstract: According to one embodiment, an apparatus for removing enamel from a person's tooth includes a blade portion and a handle portion. The blade portion includes an abrasive surface adapted to remove enamel from the tooth in response to reciprocating movement of the abrasive surface against the enamel. The handle portion is coupled to the blade portion and includes first and second regions, the first region is proximal and the second region is distal to the blade portion. The first region includes a substantially solid cross-section with a substantially circular perimeter. The second region includes a substantially solid cross-section with at least a substantially semi-circular perimeter, the solid cross-section defining a notched region. The apparatus is adapted to be inserted via a pressure fit into a corresponding opening in a driver mechanism adapted to drive reciprocating movement of the blade portion and the abrasive surface.

Abstract: A dental prophy chip with a hollow core of different shapes such as canopy, cylinder, cup and inverted cone, is covered by hydrophilic grindstone sponge containing a polishing agent and its edge is either pressed fixed or folded into the interior of the core with a latch plate. A shaft is fixed to the latch plate to avoid resonance at bottom surface, during rotation. The device maintains polishing efficiency by avoiding transverse oscillation in polishing barrel-shaped tooth clearance and reducing frictional heat.

Abstract: A dental system comprises a dental prophy angle and an adapter. The prophy angle includes a housing and a latch mechanism. The adapter is configured to drive the prophy angle. The latch mechanism includes a lever and a first latch element. The adapter includes a nose having a second latch element and a depression proximate to the latch element. Upon the first latch element mating with the second latch element, the depression adjacent the lever. The lever is movable between at least a first position and a second position, and movement of the lever between the first position and the second position moves the first latch element between an engaged position and a disengaged position.

Abstract: An adjustable angle adapter for a prophy angle comprises a nose, a rotating member, a body, a shaft, a multi-axis rotation joint, and an outer joint. The nose is configured to receive a portion of the prophy angle. The rotating member is positioned within the nose. The body is adjustably connected to the nose. The shaft is positioned within the body. The multi-axis rotation joint connects the shaft to the rotating member. The outer joint includes a ball portion connected to one of the body and the nose, and a ball receiver connected to an other of the body and the nose. The nose is configured to pivot relative to the body into at least a first configuration and a second configuration.

Abstract: The present invention discloses a self-contained dental prophylaxis angle with a separate therapeutic content lumen and drive shaft lumen. The phrophylaxis angle also provides an offset rotational axis and methods for its use in cleaning, polishing, bleaching, bonding, etching, abrading, desensitizing, or otherwise treating teeth. An offset drive system is provided to power rotation of the dental tip in a system that can be physically separated from the storage and dispensing system for therapeutic content. A self-contained dental prophylaxis angle with an offset rotational axis according to the present invention may be used with a variety of shaped dental tips of varying degrees of rigidity, according the needs of a given clinical application.

Abstract: A dental prophylaxis angle includes a body, a drive gear and a driven gear. The body has a sleeve with an open rear end, a neck, a head, a first axial bore, and a second axial bore. The first axial bore is located in the neck, and the second axial bore is located in the head. The first and second axial bores communicate with each other at an intersection. A channel extends through the body from the base of the neck to the open rear end. The drive gear is adapted to be inserted into said body through said head. The drive gear includes a gear, an intermediate portion and a shaft. The shaft extends rotatably from the open rear end of the sleeve, through the first bore, and into the second bore. The intermediate portion further includes an angled leading edge. The drive gear defines a circumferential groove between said gear and said intermediate portion. The driven gear is rotatably mounted in the head and operatively connected to the drive gear. The body further includes a lip extending into the channel.