Patents Assigned to Nakanishi Dental Mfg., Co., Ltd.
  • Patent number: 5617759
    Abstract: A mechanism for a cutting or grinding tool for converting rotational movement into reciprocating movement contains a casing, a reciprocating member mounted within the casing for receiving and securing a tool to be inserted into a tool receiving opening of the reciprocating member, a shaft member rotatably mounted within the casing for rotation by a rotational driving force, a bearing member for rotatably carrying the shaft member, and a support member for carrying the reciprocating member for enabling reciprocating movement thereon. The reciprocating member and the shaft member are spaced apart so that a center axis of the reciprocating member and a center axis of the shaft member are offset. A connecting member is provided between the shaft member and the reciprocating member for interconnecting the shaft and reciprocating members for converting rotational movement of the shaft member into reciprocating movement of the reciprocating member.
    Type: Grant
    Filed: June 12, 1995
    Date of Patent: April 8, 1997
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Eiichi Nakanishi
  • Patent number: 5616029
    Abstract: A dental treatment device for forming a screw hole for embedment of an implant material by a tool attached to the dental treatment device contains a speed-reducing unit for decelerating rotation of an external electric motor and raising torque for transmitting rotation to the tool, and a clutch unit provided between the speed-reducing unit and the tool. The clutch unit contains a driving side clutch having a first indented surface on its forward side, a tool side clutch having a second indented surface on its rear side, and a spring for thrusting the driving side clutch towards the tool side clutch for axially mating the first indented surface and the second indented surface with each other.
    Type: Grant
    Filed: June 26, 1995
    Date of Patent: April 1, 1997
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Tetsuji Suzuki
  • Patent number: 5423678
    Abstract: A dental handpiece contains a sleeve for rotatably accommodating and securing a dental treatment tool therein, bearings for rotatably holding the sleeve with respect to stationary handpiece casing members, a rotatable rotor fixed to the sleeve for rotating the sleeve under action of a compressed fluid, and stationary convexed and concave protective members for sheathing the bearings exposed to an annular spacing defined by the bearings and the rotatable rotor. The rotatable rotor contains rotatable concave and convexed disc portions. The rotatable concave and convexed disc portions are arranged in proximity to the stationary convexed and concave protective members in a mating relation therewith for defining therebetween at least a first gap and a second gap communicating with the first gap and disposed radially outwardly of the first gap.
    Type: Grant
    Filed: May 17, 1994
    Date of Patent: June 13, 1995
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Takasuke Nakanishi
  • Patent number: 5407352
    Abstract: A transparent dental tube unit contains a transparent turbine gas supply passage for allowing a pressurized gas supplied from a pressurized fluid supply source to be passed to a dental handpiece for driving a turbine provided in the handpiece, a transparent liquid supply passage for allowing a pressurized liquid from the pressurized fluid source to be passed to the dental handpiece for dissipating the heat generated by friction, a transparent enclosure tube for enclosing the transparent turbine gas supply passage and the transparent liquid supply passage therein, and a fixing device for fixing the transparent turbine gas supply passage and the transparent liquid supply passage.
    Type: Grant
    Filed: October 4, 1993
    Date of Patent: April 18, 1995
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Sosaku Kawata
  • Patent number: 5380201
    Abstract: A dental handpiece having a cleaning unit contains a turbine gas supply passage for supplying a gas under pressure to a turbine for rotationally driving a dental tool, a rinsing liquid supply passage for supplying a rinsing liquid to a turbine head, a chip-scattering gas supply passage for supplying a gas for scattering cut chips produced by operation of the dental tool, and a cleaning unit for cleaning at least one of the gas and the liquid provided in at least one of the turbine gas supply passage the rinsing liquid supply passage and the chip-scattering gas supply passage.
    Type: Grant
    Filed: October 6, 1993
    Date of Patent: January 10, 1995
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Sosaku Kawata
  • Patent number: 5252065
    Abstract: A cartridge type dental handpiece contains a handpiece main body, a head housing provided at a distal end of the handpiece main body, and a cartridge detachably adapted within the head housing. The cartridge has a cartridge casing and a rotatable sleeve rotatably mounted within the cartridge casing and adapted for detachably holding a dental burr. The dental handpiece further contains a fluid passage defined between an inner surface of the head housing and an outer surface of the cartridge casing when the cartridge is mounted within the head housing, a fluid spraying port formed in a lower surface of the cartridge casing in communication with the fluid passage for spraying the fluid from the fluid passage onto a tooth being treated, and a communication port for supplying the fluid from a fluid supply duct within the handpiece main body into the fluid supply passage.
    Type: Grant
    Filed: August 7, 1992
    Date of Patent: October 12, 1993
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Takasuke Nakanishi
  • Patent number: 5244384
    Abstract: A dental handpiece apparatus having a heating unit contains a liquid supply source, liquid flow passages for ejecting a liquid from the liquid supply source at an ejection passage provided at a distal end of a main body of a handpiece, a gas supply source, gas flow passages for ejecting a gas from the gas supply source at the ejection passage and a heating unit provided in at least one the liquid flow passages and the gas flow passages for heating at least one of the liquid and the gas.
    Type: Grant
    Filed: August 6, 1992
    Date of Patent: September 14, 1993
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Sosaku Kawata
  • Patent number: 5074788
    Abstract: A device for preventing intrusion of foreign matter into a dental handpiece includes an end cap secured to a bur sleeve for rotation in unison with the bur sleeve. Around the end cap, there are delimited gap sections the one end of which communicates with a forward or lower ball bearing positioned towards a tool inserting opening and the other end of which is opened at the foremost part of the handpiece. A discharge port passing through the main body of the handpiece and communicating with the gap sections is formed at the foremost part of the handpiece. With rotation of the bur sleeve, the end cap is rotated so that the pressure within the gap sections is decreased to suck the foreign matter, such as cut tooth particles or chips, which is expelled to outside through the discharge port under the centrifugal force of the end cap.
    Type: Grant
    Filed: February 26, 1991
    Date of Patent: December 24, 1991
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Takasuke Nakanishi
  • Patent number: 5074789
    Abstract: A chucking device for a dental handpiece includes a cutting tool, a collet having a plurality of slits to permit the cutting tool to be received and attached in position in the collet, a rotational sleeve for transmitting rotation to the collet, a locking member adapted to permit the diameter of the collet to be changed, and a coil spring thrusting the locking member along the inserting direction of the cutting tool. The outer periphery of the collet has a tapered surface adapted to be enlarged in diameter along the inserting direction of the cutting tool. The locking member is shifted along the tapered surface under the thrusting force of the coil spring to change the diameter of the collet to hold the cutting tool therein. When the locking member is pressed down against the coil spring, the locking member is then moved along the tapered surface in a direction opposite to the inserting direction of the cutting tool to release the cutting tool to permit the tool to be detached from the collet.
    Type: Grant
    Filed: September 21, 1990
    Date of Patent: December 24, 1991
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Yuichi Shibata
  • Patent number: 5037299
    Abstract: A chucking device for a dental handpiece includes a dental bur having a retention groove, a stationary disk having a central opening, a pair of locking members having projecting engaging portions for engaging with the reaction groove, a retention spring for thrusting the locking members towards abutment with each other, and a pushbutton for releasing retention of the bur. When the bur is inserted into the central opening, the retention groove is engaged by the projecting engaging portions of the locking members for retaining and securing the bur within a bur tube. When the pushbutton is pressed down, the locking members are extended apart from each other to release the retention of the retention groove by the projecting engaging portions to permit the bur to be disconnected from the inside of the bur tube.
    Type: Grant
    Filed: February 26, 1991
    Date of Patent: August 6, 1991
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Takasuke Nakanishi
  • Patent number: 4797098
    Abstract: A dental treatment apparatus includes a pressurized fluid source for pressurizing and supplying a fluid necessary for performing dental treatment operation and fluid conduits for conveying the pressurized fluid. The pressurized fluid source and a handpiece communicate with each other by the fluid conduits and a valving member is interposed in the liquid conduit for sucking the liquid during in a direction opposite to the liquid supply direction when the dental treatment operation is terminated. A check valve is interposed in the liquid conduit between the valving member and the dental treatment tool provided at the extreme end of the dental handpiece.
    Type: Grant
    Filed: April 22, 1987
    Date of Patent: January 10, 1989
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Shosaku Kawata
  • Patent number: 4619614
    Abstract: A rotational coupling device for a cordless dental instrument including a motor housing which has a pair of semi-annular projections integrally provided at a rear end thereof with a pair of arc-shaped recesses formed between the coupling projections and semi-annular slot provided around the inner peripheries of the semi-annular projections. A battery housing has a pair of semi-annular around an outer periphery adjacent its front end, a pair of arc-shaped projections coinciding with the arc-shaped recesses of the motor housing and a pair of semi-annular flanges coinciding with the pair of semi-annular projections of the motor housing so as to form a rotational coupling between the motor housing and the battery housing. An insulating disc having a pair of contacts connected to a motor fits into a rear opening of the motor housing.
    Type: Grant
    Filed: August 31, 1984
    Date of Patent: October 28, 1986
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventors: Tadashi Baba, Norimasa Kaneko
  • Patent number: 4595363
    Abstract: A device for opening and closing a chuck for a dental handpiece has a handle portion and a powerhead assembly including a hollow driving shaft having, adjacent to its outer orifice, a forwardly outwardly tapering portion defining a small diameter rear portion and a large diameter front portion. A hollow cylindrical chuck has a forwardly outwardly tapering outer peripheral surface joining a small diameter rear surface and a large diameter front surface corresponding to the respective driving shaft portions. The chuck is slidably inserted into the driving shaft. Three radial openings are formed at equally spaced positions in the forwardly outwardly tapering outer peripheral surface of the cylindrical chuck. A plate-shaped chucking die having a concave bottom surface is slidably fitted into each radial opening to hold a dental tool.
    Type: Grant
    Filed: August 2, 1984
    Date of Patent: June 17, 1986
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Takasuke Nakanishi
  • Patent number: 4578034
    Abstract: A dental handpiece has a handle portion including a powerhead assembly integrally supported on a front end of the handle portion and a base cylindrical member located in a cylindrical hollow portion of the handle portion. The base cylindrical member has a first axial central passage for a fiberscope, a second side passage for supplying air under pressure, a third side passage for supplying water and a fourth passage for exhaust. A middle connector has a large diameter front hollow portion and a small diameter rear hollow portion having internal threads, three radial openings provided through the connector at equally spaced locations, passages corresponding to the passages in the base cylindrical member and a tubular plunger slidably mounted thereon. A driven ball and a driving ball are slidably located in each radial opening for engaging a circumferential slot around an external rear end portion of a hollow mount insert threadedly fitted into the rear end portion of the base cylindrical member.
    Type: Grant
    Filed: August 31, 1984
    Date of Patent: March 25, 1986
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventors: Yuichi Shibata, Tadashi Baba
  • Patent number: 4533324
    Abstract: An air driven dental handpiece has a turbine housing mounted on one end of a handle and an outwardly and upwardly tapered annular surface around the inner bottom surface of the housing. A turbine cartridge is removably mounted in the turbine housing and has an outwardly and upwardly tapered annular surface around the periphery of the bottom thereof abutting the tapered annular surface on the inner surface of the housing and an outwardly facing outwardly and downwardly tapered annular surface around the periphery of the top. An air turbine is rotatably mounted in ball bearings in the turbine cartridge, the turbine being resiliently mounted in the cartridge in the direction of the length of the turbine shaft.
    Type: Grant
    Filed: February 7, 1984
    Date of Patent: August 6, 1985
    Assignee: Nakanishi Dental Mfg., Co., Ltd.
    Inventor: Takasuke Nakanishi
  • Patent number: 4493645
    Abstract: A device for opening and closing a chuck for a dental handpiece has a handle portion and a powerhead assembly including a hollow driving shaft having, adjacent to its front end, a fowardly outwardly tapering portion joining a small diameter rear portion and a large diameter front portion. A hollow cylindrical chuck has a forwardly outwardly tapering outer peripheral surface joining a small diameter rear surface and a large diameter front surface corresponding to the respective driving shaft portions. The chuck is slidably inserted into the driving shaft. Three radial openings are formed at equally spaced positions in the forwardly outwardly tapering outer peripheral surface of the cylindrical chuck. A disc-shaped chucking die is slidably fitted into each radial opening to hold a dental tool. A chuck pusher is held in a socket with a disc plate spring interposed between the socket and the chuck pusher, and the pusher is movable for axially displacing the chuck to hold or release the dental tool.
    Type: Grant
    Filed: June 30, 1983
    Date of Patent: January 15, 1985
    Assignee: Nakanishi Dental Mfg., Co., Ltd.
    Inventor: Takasuke Nakanishi
  • Patent number: 4490113
    Abstract: A dental handpiece has a powerhead assembly connected to a hollow handle portion including a tube supplying air under pressure, a water tube and an exhaust tube, a holding sleeve held to the hollow handle portion and a rotatably and detachable connecting means. The tube supplying air under pressure is connected through an interconnecting tube to a flexible air tube, the water tube is connected to a flexible water tube and the exhaust tube is connected to a flexible exhaust tube respectively while permitting the holding sleeve and the connecting means to rotate relative to each other about the longitudinal axis of the handpiece with a limited angle.
    Type: Grant
    Filed: January 26, 1984
    Date of Patent: December 25, 1984
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Shosaku Kawada
  • Patent number: 4460341
    Abstract: A dental handpiece having a handle portion, a powerhead assembly integrally and perpendicularly linked to the handle portion, a holding sleeve fixedly inserted in the handle portion, a driving shaft journaled in a bushing in the holding sleeve, the driving shaft including an integral disc at its outer end, the outer end surface of the integral disc being concave, the concave surface carrying at its periphery a guide pin which is directed toward the point of intersection of the axis of the driving shaft and that of a cylindrical hollow driven shaft having a spherical middle portion, the cylindrical driven shaft being rotatably mounted in the powerhead assembly in bushings, the spherical middle portion of the cylindrical driven shaft having a longitudinal concave guide slot and the guide pin being slidably inserted into the longitudinal concave guide slot to couple the driving shaft with the cylindrical driven shaft, and a dental tool on the cylindrical driven shaft, whereby the dental tool is driven so as to r
    Type: Grant
    Filed: September 23, 1982
    Date of Patent: July 17, 1984
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Toshimasa Nakanishi
  • Patent number: 4433957
    Abstract: The present transmission gear for a dental handpiece generally has a handle portion including a biased guide slot and a holding sleeve fixedly held in the handle portion, a first cylindrical hollow driven shaft, a second driven shaft having at its rear end portion an axial central cavity and fixedly inserted into the first driven shaft, a shiftable clutch shaft having a drive pin, a collar bearing including a slidable pin and a crossed male lug and journaled rotatably in the central hollow, a planetary gear train provided at the rear end portion of the clutch shaft, and a drive gear coupled to the motor to be engaged with the clutch shaft whereby the clutch shaft is either coupled to the drive shaft or disengaged therefrom by the alternative rotation of an operating ring to deliver either a direct transmission of the motor rotation or reduced speed rotation thereof to a dental tool.
    Type: Grant
    Filed: February 22, 1982
    Date of Patent: February 28, 1984
    Assignee: Nakanishi Dental Mfg. Co., Ltd.
    Inventor: Toshimasa Nakanishi
  • Patent number: 4403956
    Abstract: A dental handpiece including a powerhead assembly connected to an outer sleeve handle portion in which is located a sleeve bearing, a rotatable, disconnectable connecting means being provided in the sleeve bearing. A first optical fiberscope extends from the front end portion of the powerhead near the dental tool into the front end of the sleeve bearing adjacent to the front end of the connecting means. A thickened fiberscope abuts the rear end of the first fiberscope and extends rearward through the handpiece to a light source. Cavities, passages and pipes are provided in the sleeve bearing and connecting means in order to provide a smooth flow of compressed air, chip air, water and exhaust to or from the powerhead assembly while permitting the sleeve bearing and connecting means to rotate relative to each other about the longitudinal axis of the handpiece.
    Type: Grant
    Filed: July 13, 1981
    Date of Patent: September 13, 1983
    Assignee: Nakanishi Dental Mfg., Co., Ltd.
    Inventor: Takasuke Nakanishi