Abstract: A control device for use in an air turbine dental handpiece comprising an air turbine which is integrated with a spindle supporting a cutting tool and is rotatably supported in a head housing by bearings, an air supply passage which supplies compressed air to the air turbine and an exhaust passage which discharges air spent to drive the air turbine, the control device being characterized in that the control device comprises a pressure or flowrate regulating device disposed in the exhaust passage to control the speed of the turbine in the range of stop to high-speed operation by changing the back pressure of the air turbine.

Abstract: A brushless DC micromotor made up of a stator coil and a rotor housed inside thereof with magnet poles formed therein, which micromotor is characterized in that the stator coil is formed by coaxially winding more than one coil sheet formed on an insulating sheet, on which coil sheet a plurality of coil patterns are continuously provided in series in the direction of winding. The motor of the present invention can be made smaller, thinner and lighter than the conventional counterpart made by the use of a wound copper wire coil.

Abstract: A dental radiographic apparatus for photographing the entire jaws in which the apparatus includes a rotary arm having an X-ray source at one end and an X-ray film cassette at the other end thereof and operating in the manner that a path of movement of X-ray beam with respect to the dental arch describer a symmetrically extending approximately triangular envelope projecting toward the front tooth region of the dental arch by sequentially shifting the center of rotation of the X-ray beam irradiated from the X-ray source upon the X-ray film cassette, the apparatus being characterized in that it comprises a means for changing the straight-line distance on the medial line of the human body between the apex and receding points of limit of the envelope.

Abstract: A vertical movement and fixture device to be used for, for instance, a dental tomograph for photographing entire jaw including a vertical support having a vertical groove inside, a block base which is slidably fit in the groove and is fixed to a slider and a means for fixing and releasing the block base at any desired position in the groove, the means for fixing and releasing the base block comprising a horizontal shaft, a pair of links each one end of which is swingably connected to one end of the horizontal shaft respectively, a pair of brake shoes which are respectively secured to the other ends of the links, and an operation member which supports and vertically moves the other end of the horizontal shaft. According to the device, the block base can be firmly fixed to and released from the support simply by applying slight control force and the cost of the device is low since its construction is entirely mechanical.

Abstract: A device for controlling a headrest of a treatment equipment to be used for dental and medical treatment. The device comprises an arcuate support shaft connected to said headrest with the center of radius of curvature of the shaft positioned above said backrest, a guide sheath provided inside the top of said backrest, said sheath having an arcuate guide groove slidably receiving said support shaft, a lock mechanism for locking said support shaft in a suitable position in said guide groove, and lock releasing mechanism for unlocking said support shaft.

Abstract: An automatic exposure device for obtaining X-ray pictures with superior quality and constant contrast by feedback of both tube voltage and tube current according to the residual X-ray dose which penetrates the body of a patient. This device is further characterized in that the feedback control is compensatingly done according to the changes in the tube voltage and tube current caused by fluctuations of the power supply.

Abstract: A dental treatment chair including a seat, a backrest tiltably attached to the seat, and a drive means for tilting the backrest. The chair includes a unit table which stays horizontal and moves and up and down as the backrest tilts, and the table is further connected to the backrest by a longitudinal shaft and a support shaft so that it can freely rotate in a horizontal plane. By means of this structure, an operator can take a position convenient to access treatment tools and to take a position opposite to the unit table in response to each tilting phase of the backrest.

Abstract: A speed change device arranged such that a driving shaft connecting with a driver and a tool working shaft connected with a driven tool are connected with each other for transmission of torque in the no speed change mode or in the speed change (acceleration or deceleration mode and wherein a manipulating sleeve on the outer periphery of the handpiece case is used for selecting either the no speed change or the speed change mode thereby saving the expense of providing alternative devices for the individual modes of torque transmission.

Abstract: A radiographic apparatus for photographing the entire jaws designed to make a tomogram of a curved plane approximate to a dental arch by the locus of center of rotation of the X-ray beam projected from an X-ray source onto an X-ray film holder describing an approximately V-shaped envelope which forms an apex on an approximate medial line and recedes from the apex toward the left and right of the approximate medial line by moving a rotary arm around a patient, the arm having the X-ray source at one end and the X-ray film holder at the other end thereof, wherein the apparatus comprises a means for changing straight-line distance on the approximate medial line between the apex and receding point of limit of the envelope and a means for indicating the distance of shift thus changed or a means for automatically moving the indication means a distance equal to the distance of shift.

Abstract: A dental panoramic X-ray photographing apparatus including a rotary arm having an X-ray generator disposed at one end thereof and having an X-ray film cassette holder disposed at the other end thereof in an opposite relation with each other around an object disposed therebetween. The apparatus comprises a first control means for controlling the rotation speed of the arm by detecting the rotation position of the arm and a second control means for controlling the tube voltage and the tube current of the X-ray generator by comparing the feeding speed of the X-ray film at the X-ray film cassette holder with the residual X-ray dose which has passed the object and the film, whereby it is intended to provide the simultaneous control function of the tube voltage and the tube current, the function for automatic exposure throughout the entire teeth and the function for compensating for the density of the central portion of the front tooth region of a dental arch at the same time.

Abstract: A sudden stop circuit for a brushless micromotor comprising a means for detecting the off state of the on/off switch of the brushless micromotor and a means for applying a locking pulse signal to at least one motor coil for a specified period depending on the off state detection signal generated by the detection means, whereby the motor rotor is braked by the electromagnetic force generated in the motor coil by the locking pulse signal. This circuit is compact and can apply great braking force to stop the motor in an extremely short time.

Abstract: This disclosure relates to a small-sized, high-power micromotor with built-in cooling medium pipes for medical treatment. The motor which is structurally of the type wherein the stator of the motor includes a permanent magnet and a magnetic yoke encircling the magnet is improved in that the cooling medium pipes are incorporated into the motor by providing at least one cooling medium pipe receptor portion in the magnetic poles of the yoke or in the vicinity of the yoke without reducing motor performance nor increasing the diameter of the motor.

Abstract: An improvement in an air bearing device of an air drive, air journal type dental handpiece is disclosed, wherein a radial gap for journaling a rotor in the radial direction comprises partially enlarged gaps which, serving as air pools, improve the handpiece's cutting performance and prevent abnormal noise and vibration of the turbine blade caused by the whirl phenomenon.

Abstract: This disclosure relates to an improved method for driving a hand-piece of the air drive type to improve its cutting performance, and to increase its cutting load in a low range of rotational speed in particular, and also relates to a device for practicing the method. The disclosed method employs compressed high-velocity fluid exhausted to one side of an annular space in which blades rotate after having once been jetted at said blade guided along the rotating direction of said blades and then causing it to reenter the annular space in a diagonal direction with respect to the rotational direction of the blades for further driving the running blades in the same sense. The device includes a simply machined ring-shaped adapter.

Abstract: A contra angle handpiece of this invention employs a laser beam transmitting glass fiber for dental treatment in such a manner that the transmission of the beam is carried out not by a reflecting mirror, but by a glass fiber centripetally held with respect to the handpiece by means of resilient grip members. As a result, the disadvantages of the prior art such as reflection factor reduction and reflection angle changes, which result from the use of a reflecting mirror in a contra angle dental handpiece, are eliminated.

Abstract: This disclosure relates to a simple mounting structure for a dental X-ray apparatus. The structure is used in combination with a substantially horizontal treatment bed in such manner that irradiation tube of an X-ray head is designed to take a correct position with respect to the mouth region of a patient lying on the treatment bed with his head resting on the headrest of the bed. The structure includes the treatment bed, an X-ray head support connected to one side of the bed and made up of an assembly of a plurality of hollow tubes adjustable in length in the three-dimensional directions of length, width and height of the bed and an X-ray head mounted at the end of the support and swingable in a back-and-forth direction with respect to an axis of the irradiation tube. The irradiation tube is mounted on the X-ray head and movable toward and away from the mouth region. The structure permits simple and correct positioning of the X-ray apparatus with respect to a patient lying on the bed.

Abstract: The present invention relates to a balancing device for vertically movable dental arms such as a dental light arm and a dental tray arm, and more specifically to a balancing device which is capable of accurately positioning the arm at any desired position by sufficiently balancing the weight of a load head with the force of the spring member coaxially inserted in the arm. The balancing device features compact size, low cost and high operability.

Abstract: This disclosure relates to improvements in a dental treatment chair assembly including a unit table having various instruments attached thereto in combination with a unit arm mechanism. The assembly is so constructed that the unit arm mechanism is made slidable in the direction of the mechanism crossing (preferably at right angles with) the body axis of the chair. Such construction makes it possible to meet the convenience of both a doctor and a nurse in their operation of the instruments in dental treatment.

Abstract: This disclosure relates to a rotation control device for an air-drive and air-journal type dental handpiece, wherein rotation control is made by applying a braking force to an air journaled turbine for a certain time by the use of compressed air operated air timer and a closing valve. When the braking force is applied to cut off drive air to the turbine, there is produced negative pressure in the bearing mechanism by the inertial rotation of the turbine, whereupon negative pressure causes the turbine to suck dirt thereinto. There is also a danger of the operator being hurt by idle rotation of the cutting tool which is rotated together with the turbine. The device of the invention prevents effectively this kind of sucking up dirt and injury to operators.

Abstract: This disclosure relates to a dental radiographic apparatus for photographing the entire jaws designed to control the rotation of a rotary arm such that the film surface of a film holder mounted at one end of the rotary arm may rotate and move substantially at equal speed substantially equidistantly along the dental arch and that the X-ray beams irradiated upon the film surface from an X-ray generator mounted at the other end of the arm may fall on the dental arch at any point thereof at right angles with the arch. The apparatus makes it possible to obtain a very clear tomographic picture of a curved plane of the entire jaws, the picture being free of a double image of the teeth, partial change in enlargement ratio of the image obtained, and partial difference in the shade of the image obtained.