Nakanishi Inc.

Nakanishi Dental Mfg. Co., Ltd.

Nakanishi Dental Manufacturing Co., Ltd.

Takasuke Nakanishi

Chikao Yazawa

The medical handpiece of the present invention has a cutting tool having a flexible shank and a bur provided at the distal end of the cutting tool for cutting an affected area, a tubular sheath for receiving the cutting tool therein, and a handpiece body for detachably holding the proximal end of the cutting tool and transmitting driving force from a drive source to the cutting tool. The sheath and the cutting tool are made flexible for a particular range, with the sheath being plastically deformable and the shank of the cutting tool being elastically deformable. The medical handpiece is further provided with a plurality of bearings arranged in the sheath, first interposed members that are tubular and flexible and arranged proximal to, distal to, and between the bearings, and second interposed members that are tubular and flexible and arranged inside the first interposed members.

Medical handpiece

A dental handpiece is disclosed, which includes a burr sleeve, upper and lower ball bearings for rotatably supporting the burr sleeve, a rotor fixed to the burr sleeve between the upper and lower ball bearings and rotated for rotatably driving the burr sleeve, and a dust controller. The dust controller includes a rotary protruding member fixed on the outer surface of the burr sleeve and rotating integrally with the burr sleeve, and a stationary protruding member attached to a stationary part of the handpiece and having a surface facing to the rotary protruding member to define a gap therebetween located outside of the lower ball bearing. The upper and lower ball bearings are angular contact ball bearings each having a bearing cage. The bearing cage has apertures that support bearing balls therein and are located in the middle of the bearing cage in the thrust direction.

Dental handpiece with angular contact ball bearings

There is disclosed a light guide unit including a bunch of glass fibers capable of transmitting light from a light source to a desired site, a sheath of a thermocontracting resin contracted to cover the bunch of glass fibers for substantially its overall length, and a filler of a hardening resin hardened to fill spaces between the glass fibers within the sheath. Also disclosed are a method for producing the light guide unit, and a dental handpiece having the light guide unit.

Light guide unit, method for producing the same, and dental handpiece having light guide unit

Prophy head for a handpiece used in dentistry. The prophy head has a rotating shaft which holds a polishing member, a bearing for supporting the shaft, a housing for retaining the bearing, and a rotary dust control device which rotates with the shaft and prevents intrusion of contaminants. The dust control device has a surface extending radially outwardly from the shaft and downwardly beyond the lower end of the housing, and a surface in close proximity to the inner surface of the lower end of the housing.

Prophy head

A dental handpiece is disclosed which has a housing having a wall, a bur sleeve for receiving and holding a dental tool therein, a bearing for rotatably supporting the bur sleeve, a rotary dust control member fixed on the bur sleeve, and a stationary dust control member forming a gap in cooperation with the rotary dust control member and the wall of the housing for preventing entry of contaminants inside the housing. The stationary dust control member is attached to the bearing.

Dental handpiece with dust control mechanism

A dental handpiece is disclosed which includes:

Dental handpiece with baffle for stabilizing rolling bearing cage

A dental hose assembly for use with a dental handpiece. The assembly comprises inner tubes, an outer tube enclosing the inner tubes, a connector for connecting the inner tubes to fluid passages in the handpiece, a tubular hose guide enclosing the distal ends of the inner tubes, a tubular joint cover engaging the connector and the distal end portion of the outer tube, and a connector ring sheathing the joint cover and to be connected to the handpiece for preventing the connector from being detached from the handpiece. The connector has a proximal end connected to the inner tubes and a distal end to be connected to the dental handpiece. The hose guide has a frustconical portion proximally tapered and distally flared on its outer surface to end with a projected distal end. The distal end portion of the outer tube is fitted over the hose guide to define an expanded portion. The joint cover has a proximal end thickened radially inwardly with a rounded outer edge. The expanded portion of the outer tube is tightly held between the hose guide and the joint cover. The projected distal end of the frustconical portion and the joint cover tightly press the expanded portion therebetween and the expanded portion is fastened distally by the thickened proximal end of the joint cover.

Dental hose assembly

A center injection type dental handpiece contains a cutting bar having a hollow axially penetrating the bar, holding means for detachably holding the bar, rotating means for rotating the bar, a water injection nozzle communicating with a cooling water feed source. The water injection nozzle is inserted into the hollow of the bar for injecting a cooling water from tip of the bar. The handpiece further contains a packing for sealing a gap between the outer periphery of the nozzle and the inner periphery of the bar at the proximal end of the bar.

Water injection type dental handpiece

Cartridge for a dental handpiece

An exchangeable cartridge for a dental handpiece includes first dust-proofing members for preventing foreign matter from being intruded into an upper bearing and second dust-proofing members for preventing foreign matter from being intruded into a lower bearing. The first dust-proofing members have an upper rotational partitioning member and an upper fixed partitioning member. The upper rotational partitioning member has a protrusion provided above the upper bearing and protruding radially outwardly. The upper fixed partitioning member has a radially inwardly protruding portion lying adjacent and parallel to the protrusion of the upper rotational partitioning member to define a first interstice leading to the upper bearing. The second dust-proofing members have a lower rotational partitioning member and a lower fixed partitioning member. The lower rotational partitioning member has a protrusion provided below the lower bearing and protruding radially outwardly. The lower fixed partitioning member has a radially inwardly protruding portion lying adjacent and parallel to the protrusion of the lower rotational partitioning member to define a second interstice leading to the lower bearing.

Exchangeable cartridge for dental handpiece

A surgical handpiece contains a spindle detachably holding an elongate bar for surgical operation and transmitting rotation to the bar, an elongate sheath covering the bar except for the distal portion thereof, and a plurality of balls provided in the proximity of the distal end of the sheath, with the balls being arranged in one cross-sectional plane. The balls have a diameter approximately equal to a thickness of the sheath in the proximity of the distal end thereof, and the balls are projected slightly radially inwardly from the inner surface of the sheath with the peripheral surface of the ball being spaced from the bar.

Surgical handpiece

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.

Handpiece having bearing protective member

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.

Cartridge type dental handpiece

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.

Device for preventing intrusion of foreign matter into dental handpiece

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.

Growing community of inventors

Kanuma, Japan

Takasuke Nakanishi