JP2017104251A - Dental handpiece and suction prevention ring sheet thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dental handpiece capable of preventing cross contamination between a patient and an operator, and between a patient and a patient by preventing a foreign material such as saliva and blood from entering from, especially, a gap of a bearing in a head part.SOLUTION: The dental handpiece according to the present invention includes a suction prevention ring sheet 41 disposed at a gap area S2 between a lower face of a bearing 24 located on the lower side of a vane wheel 11 in a head part 2 and an inner bottom part 5a of a housing 5, so as to be floatable therein and in non-contact with a tool holding member 12. When the pressure in the head part 2 is positive, the suction prevention ring sheet 41 is moved in a direction of the inner bottom part 5a of the housing 5 and, when the pressure in the head part 2 is negative, the suction prevention ring sheet 41 is brought into close contact with the lower face of the bearing 24 to close the annular gap S2 located between an inner ring 24a and an outer ring 24b of the bearing 24.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a dental hand piece and a suction prevention ring sheet thereof, and more specifically, for example, a foreign material can be prevented from entering a head portion due to a suck back phenomenon occurring in the head portion of a dental air turbine handpiece. The present invention relates to a dental handpiece designed to prevent cross-infection between a patient and an operator and between a patient and a patient, and a suction prevention ring sheet used for the dental handpiece.

  For example, in a dental air turbine handpiece, a tool holding member that supports an impeller is rotatably accommodated in a head portion by a bearing, and the impeller is moved by air injected from an air supply port formed in the head portion. A tool holding member that holds a required tool is driven to rotate, and the air is discharged from an exhaust port formed in the head portion.

  In such a dental handpiece, even if the supply of high-pressure air into the head portion is stopped, the impeller and the tool holding member continue to rotate for a while due to inertia, and this rotation forms the inside of the head portion. The air in the space is discharged to the outside, and this space is in a negative pressure state. As a result, outside air is sucked into the head portion through the gap existing in the head portion.

  That is, when the rotation of the tool is stopped during dental treatment, a phenomenon (suckback phenomenon) occurs in which the patient's saliva and blood, as well as the cut toothpaste and the like are sucked into the head portion together with the saliva and the like. .

  For this reason, measures to prevent the suck back phenomenon are extremely important from the viewpoint of preventing cross-infection between patients and surgeons and between patients and patients.

  Patent Document 1 is a dental handpiece for which the applicant of the present application has previously obtained a patent, in which an impeller is rotatably accommodated in a head portion, and is injected from an air supply port formed in the head portion. A bearing located at the lower portion of the impeller is configured to rotate the impeller and a required tool held by the air and discharge the air rotating together with the impeller from an exhaust port formed in the head portion. A ring sheet is mounted and fixed so as to be sandwiched between the lower surface and the bottom of the head. The ring sheet is formed so that at least an inner diameter does not contact the rotating shaft, and a plurality of cuts are provided from the inner diameter to the outer diameter direction, and the blade When the pressure in the head part becomes positive during the rotation of the vehicle, the fan-shaped piece formed by cutting the ring sheet is pushed open by bending toward the bottom part of the head part, and the wings When the rotation of the vehicle stops, the pressure in the head part becomes negative pressure, the fan-shaped piece is sucked into the head part and closely contacts the lower surface of the bearing, and by closing the annular gap between the inner ring and the outer ring of the bearing, A dental handpiece configured to prevent entry of foreign matter into the head portion is disclosed.

However, in the case of the dental handpiece of Patent Document 1, not only the negative pressure but also the elasticity of the ring sheet is used to closely adhere the ring sheet to the lower surface of the bearing.
(1) The supply of high-pressure air is wasted and the wear of the ring seat is fast,
(2) Due to the elasticity of the ring sheet, the impeller will not start rotating unless the pressure in the head becomes a certain level of air pressure, and suddenly starts rotating at a high speed. Therefore, centrifugal force suddenly acts on the bar chuck holding the tool. There is a risk that the bar (tool) will fly (if the play part of the bearing or the bar chuck is misaligned),
(3) Because the bar chuck rotates rapidly, impact is applied to the bearings and retainer, shortening the service life.
(4) Oil is scattered by the rapid acceleration of the bar chuck, which also shortens the bearing life.
(5) Spray oil for lubrication and dirt (wear powder such as retainers) tend to stay in the bearing.
Etc. are included.

  In Patent Document 2, a rotating cylinder that holds a cutting tool and an impeller that is externally fixed to the rotating cylinder are accommodated in a head portion, and air supplied from an air supply port is applied to the impeller so that the impeller In a dental cutting apparatus that applies rotation to the impeller and discharges air impinging on the impeller from the exhaust port, the head portion is disposed at a portion facing the outer peripheral end of the impeller, and from the central axis of the rotating cylinder Proposed is a dental cutting device comprising a first gap extending in an orthogonal direction and a second gap adjacent to one or both ends of the impeller in the direction of the central axis and communicating with the first gap. Has been.

  However, in the case of the dental cutting device of Patent Document 2, the first gap that extends in the direction orthogonal to the central axis of the rotating cylinder in the portion facing the outer peripheral end of the impeller, and the impeller in the direction of the central axis. Adopting a complicated configuration that forms a second gap that is adjacent to one end side or both end sides and that communicates with the first gap, and that foreign matter from the gap between the inner ring and the outer ring of the bearing below the impeller No inhalation prevention measures have been taken.

Japanese Patent No. 5599103 JP 2003-325546 A

  The object of the present invention is to prevent the entry of foreign matter such as saliva and blood from the gaps around the cutting tool, particularly the gaps of the bearings, in view of the above-described prior art and the technique of Patent Document 1. It is an object of the present invention to provide a dental handpiece that can be configured to prevent cross contamination between a patient and an operator and between a patient and a patient.

  Another object of the present invention is to provide a suction prevention ring sheet that can effectively prevent cross-contamination between a patient and an operator and between a patient and a patient by being mounted on the dental handpiece.

  In the present invention, a tool holding member that supports an impeller is rotatably accommodated in a head portion by a bearing, and a required tool is passed through the impeller by air jetted from an air supply port formed in the head portion. A dental handpiece that rotationally drives a tool holding member to be held and discharges the air from an exhaust port formed in the head portion, wherein each of the bearings located in the lower portion and the upper portion of the impeller in the head portion. The tool is floatable in one or both of the lower surface, the upper surface, the lower surface of each bearing, the housing constituting the head portion located at the upper portion of the upper surface, and the gap region between each inner bottom portion of the holding bracket, and the tool The holding member is provided with one or two suction prevention ring sheets arranged in a non-contact state, and when the impeller rotates, the pressure in the head portion becomes a positive pressure. The prevention ring sheet is moved to one or both of the inner bottom portions of the housing and the holding bracket, and the pressure in the head portion becomes negative when the impeller stops rotating, thereby preventing the one or two suctions. The ring sheet is moved in one or both of the lower surface direction of the lower bearing and the upper surface direction of the upper bearing, and is brought into close contact with one or both of the lower surface of the lower bearing and the upper surface of the upper bearing, By closing one or both of the annular gap between the inner ring and the outer ring of the bearing and the annular gap between the inner ring and the outer ring of the upper bearing, one of the bottom side of the head part and the upper side of the head part Alternatively, the main feature is that the foreign body can be prevented from entering the head portion from both sides.

  According to the dental handpiece of the first aspect of the present invention, the following effects can be obtained.

  That is, even if the pressure in the head part becomes negative when the tool is stopped, both from the bottom part of the head part or from the top part of the head part, or both the bottom part side of the head part and the top part of the head part Intrusion of foreign matter into the head portion from the head can be prevented.

  In particular, the conventional ring sheet prevents suction action by contacting a member that rotates at a high speed, whereas the suction prevention ring sheet according to claim 1 wears due to contact with the rotating member. Therefore, durability can be improved in each stage without wasting the supply of high-pressure air.

  Therefore, it is possible to prevent foreign matters such as saliva and blood from entering the head portion due to deterioration over time, and safety and reliability can be improved.

  In the case of the suction prevention ring sheet, since it adheres to the lower surface of the bearing due to the negative pressure, even if oil adheres, there is no slit as in Patent Document 1, so that the air tightness is increased by the oil adhesion. The suction prevention ring sheet can be tightly adhered to the bearing, and the braking effect is increased.

  Since the suction prevention ring sheet is floating, the spray oil can wash away dirt (abrasion powder such as retainer) inside the bearing.

  Moreover, it is possible to prevent the turbine sound rotating at high speed from reverberating to the outside by the suction prevention ring sheet.

  Furthermore, since it is possible to remove the head cap and easily attach the anti-suction ring sheet to dental handpieces that have not taken measures against foreign object intrusion, Is also effective.

  According to the second aspect of the present invention, the outer peripheral portion of the suction prevention ring sheet is fixed to the inner peripheral portion of the lower outer ring of the lower bearing or the inner peripheral portion of the upper outer ring of the upper bearing. A gap between a lower surface or an upper surface and a housing inner bottom step portion that supports the lower end surface of the outer ring formed in the head portion, or a gap between an inner bottom step portion of the holding bracket that supports the upper end surface of the outer ring. The foreign matter can be prevented from entering the head portion from the bottom side of the head portion or from the top side of the head portion, and the invention according to claim 1. The same various effects as described above can be exhibited.

  According to the third aspect of the present invention, the suction prevention ring sheet used for the dental handpiece according to the first aspect of the present invention is made of an elastic material, so that the positive pressure in the head portion and the negative pressure can be reduced. Floating and bending can be executed reliably.

  Also, by adjusting the wall thickness of the suction prevention ring sheet and its sheet width (changing the inner diameter with a constant outer diameter), it is possible to handle various air turbine handpieces and to respond to fluctuations in the pressure of the supply air it can.

  According to invention of Claim 4, the suction prevention ring sheet used for the dental handpiece which concerns on invention of Claim 2 consists of an elastic material, The thickness is a dimension of the tool holding member length direction of the said space | gap. By adopting a thinner configuration, it is possible to reliably perform floating and bending at the time of positive pressure and negative pressure in the head portion, and make the thickness thinner than the dimension of the gap in the length direction of the tool holding member. Thus, the obstruction to the air flow discharged from the bottom of the head portion can be reduced.

  As in the first aspect of the invention, by adjusting the thickness of the suction prevention ring sheet and the sheet width (changing the inner diameter with a constant outer diameter), various air turbine handpieces can be used. It is possible to cope with pressure fluctuations.

  According to the invention described in claim 5, the suction prevention ring sheet according to the invention described in claim 3 or 4 is made of a heat-resistant material such as Teflon (registered trademark), for example, so that it can be adapted to the autoclave. it can.

  According to a sixth aspect of the present invention, in the dental handpiece suction prevention ring sheet according to any one of the third to fifth aspects, the surface of the dental handpiece is provided with a concentric convex portion, thereby providing a blade. Brake performance when stopping the car can be improved.

FIG. 1 is a schematic plan view of a dental handpiece according to Embodiment 1 of the present invention. FIG. 2 is a schematic enlarged perspective view of a head portion in the dental handpiece according to the first embodiment. FIG. 3 is an enlarged cross-sectional view taken along line AA of FIG. 2 and is a view showing a position of the suction prevention ring sheet in a positive pressure state. FIG. 4 is an enlarged cross-sectional view taken along line AA of FIG. 2 and shows a position of the suction prevention ring sheet in a negative pressure state. FIG. 5 is a partially enlarged explanatory view showing a state of the suction prevention ring sheet with respect to the bearing lower surface of the head portion in the dental handpiece according to the first embodiment at the time of positive pressure and negative pressure. 6 is a cross-sectional view taken along line BB in FIG. FIG. 7A is a perspective view of the suction preventing ring sheet according to the first embodiment, and FIG. 7B is a plan view of the suction preventing ring sheet according to the first embodiment. FIG. 8 is a plan view of the head unit according to the first embodiment when the impeller is removed and viewed from above the head unit. FIG. 9 is an enlarged cross-sectional view of the head portion of the dental handpiece according to the second embodiment of the present invention, and is a view showing the position of the suction prevention ring sheet in the positive pressure state. FIG. 10 is an enlarged cross-sectional view of the head portion of the dental handpiece according to the second embodiment of the present invention, and is a view showing the position of the suction prevention ring sheet in the negative pressure state. FIG. 11 is a partially enlarged explanatory view showing the state of the suction preventing ring sheet with respect to the bearing lower surface of the head portion in the dental handpiece according to the second embodiment at the time of positive pressure and negative pressure.

  The present invention is configured so that foreign matter such as saliva and blood can be prevented from entering through gaps generated around the cutting tool, particularly bearings, thereby preventing cross contamination between patients and surgeons and between patients and patients. For the purpose of providing a dental handpiece that can be prevented, a tool holding member that supports an impeller is rotatably accommodated in a head portion by a bearing, and is injected from an air supply port formed in the head portion. A dental handpiece that rotates and drives a tool holding member that holds a required tool via the impeller and discharges the air from an exhaust port formed in the head portion. The gap between the lower and upper surfaces of the bearings located at the lower and upper portions of the impeller, the housing constituting the head portion located at the lower and lower portions of the bearings, and the inner bottom portions of the holding brackets. A lower surface of a seal part that is floatable in one or both of the areas and is arranged in a non-contact state with the tool holding member, and whose outer peripheral portion is fixedly disposed on the lower or upper inner peripheral portion of each bearing. One or two suction prevention ring sheets facing the air gap between the upper surface and the outer ring lower end surface or the housing inner bottom stepped portion supporting the lower end surface of the outer ring formed on the inner bottom part of the head or the holding bracket. And when the impeller rotates, the pressure in the head part becomes positive, and the suction prevention ring sheet is placed with the outer peripheral part of the one or two suction prevention ring sheets facing the gap. Move to one or both of the lower surface direction of the lower bearing and the upper surface direction of the upper bearing to make contact with one or both of the lower surface of the lower bearing and the upper surface of the upper bearing. When the pressure in the portion becomes negative, the one or two suction prevention ring sheets are placed in the lower surface direction of the lower bearing and the upper surface direction of the upper bearing with the outer peripheral portion facing the gap. Move to one or both of them, and make close contact with one or both of the lower surface of the lower bearing and the upper surface of the upper bearing, an annular gap between the inner ring and the outer ring of the lower bearing, By blocking one or both of the annular gaps between the outer ring and the head part, it is configured to prevent foreign matter from entering the head part from one or both of the bottom side of the head part and the top side of the head part. It was realized.

  Hereinafter, a dental handpiece and a suction prevention ring sheet according to an embodiment of the present invention will be described in detail with reference to the drawings.

  A dental handpiece 1 and a suction prevention ring sheet 41 according to Example 1 of the present invention will be described with reference to FIGS. 1 to 8.

  As shown in FIGS. 1 and 2, the dental handpiece 1 according to the first embodiment of the present invention includes a head portion 2 and a main body portion 3, and a dental treatment device (not shown) is disposed behind the main body portion 3. Hose joint 4 is provided.

  Then, the compressed air supplied from a dental treatment device (not shown) is configured to be supplied into the head portion 2 from an air supply port 14 (see FIG. 6) in the head portion 2 via the hose joint 4. .

  Next, the head unit 2 will be described in detail with reference to FIG.

  The head portion 2 includes a housing 5, an impeller 11 is accommodated in the housing 5, a tool for supporting the impeller 11 and the impeller 11 and mounting a tool (not shown) from below. The holding member 12 is rotationally driven by the air injected from the air supply port 14 of the air supply line 13 formed in the main body 3, and the air flowing along with the rotation of the impeller 11 is formed in the housing 5. The exhaust port 15 is configured to be exhausted through an exhaust pipe line 16 formed in the main body 3.

  At this time, the flowing air flows into the exhaust pipe 16 and at the same time is discharged from the gap of the push cap 21 and the gap 23 of the bottom 22 of the housing 5 to the atmosphere.

  In this case, on the bottom 22 side, the air passes through an annular gap S1 between an inner ring 24a and an outer ring 24b of a bearing 24 mainly made of, for example, stainless steel, which is located below the impeller 11, and further, It is discharged through a gap 23 in the bottom 22.

  A suction prevention ring made of a floating elastic material and a heat-resistant material as shown in FIGS. 7A and 7B, which will be described in detail later, on an inner bottom portion 5a located below the bearing 24 in the housing 5. The sheet 41 is arranged.

  The bearing 24 includes a ball 24c and a retainer 24d in addition to the inner ring 24a and the outer ring 24b. The upper bearing 29 has the same structure as the bearing 24.

  The impeller 11 has a structure in which a required number of blades are formed to protrude in the radial direction with a tool holding member 12 that allows a tool (not shown) being detachable as a rotation axis.

The tool holding member 12 has a cartridge structure in which the bearing 24 and the upper bearing 29 are press-fitted with the impeller 11 interposed therebetween.
The tool holding member 12 has a structure in which a holding portion (not shown) is opened and closed by pushing the push cap 21 from above against the elastic force of the spring 30 so that the tool can be attached and detached.

  An O-ring 26 is mounted between the bearing 24 and the housing 5, and an O-ring 27 is mounted between the bearing 29 and a holding bracket 31 that covers the bearing 29.

  FIG. 8 shows a state in which the head cap 28, the holding bracket 31, the impeller 11, the bearing 24, the bearing 29, and the tool holding member 12 are removed from the head portion 2 and viewed from above the head portion 2.

  Next, the bearing 24 and the suction prevention ring sheet 41 will be described in more detail with reference to FIGS.

  As shown in an enlarged view in FIG. 5, the bearing 24 includes the inner ring 24 a, the outer ring 24 b, the ball 24 c, and the retainer 24 d, and an outer peripheral part 32 a is provided at an inner peripheral part below the outer ring 24 b of the bearing 24. A thin annular shield body 32 having a step, for example, made of stainless steel, which is a seal part which is fixed to the provided seal part mounting recess 24e in an arrangement orthogonal to the inner ring 24a, and the shield body 32 is connected to the outer ring 24b. It is also made of a stainless steel thin ring-shaped retaining ring 33 that is secured to the lower seal part mounting recess 24e.

  The shield body 32 is formed in a dish shape in which the central portion 32b has a lower step than the outer peripheral portion 32a, and the inner diameter portion inside the central portion 32b is set to a size that does not contact the outer periphery of the inner ring 24a.

  The retaining ring 33 has a flat and thin annular shape, and has a small width that fixes and supports only the outer peripheral portion 32a of the shield body 32 with respect to the seal component mounting recessed portion 24e.

  The suction prevention ring sheet 41 disposed on the inner bottom portion 5a of the housing 5 located below the bearing 24 has a central hole portion 42 having a dimension that does not contact the tool holding member 12, and has an outer diameter thereof. The inner bottom portion 5a, the lower surface of the inner ring 24a of the bearing 24, the shield body 32, and the retaining ring 33 are slightly smaller than the inner diameter of the inner bottom portion 5a of the housing 5 according to the pressure fluctuation in the head portion 2. The gap region S2 between the lower surface and the lower surface is configured to be able to float (floating up and down in the state shown in FIG. 3).

  Next, the suction preventing ring sheet 41 will be described in more detail with reference to FIG.

  The suction prevention ring sheet 41 is preferably made of an elastic material, and is preferably a Teflon (registered trademark) material that is heat resistant even when autoclaved (sterilized by a sterilizer), but is limited to a Teflon (registered trademark) material. It is not a thing.

  Further, the thickness dimension of the suction preventing ring sheet 41 can be an arbitrary thickness dimension as long as it bends in response to fluctuations in air pressure in the head portion 2.

  Next, the action and effect of preventing the entry of foreign matter into the head portion 2 by the dental handpiece 1 and the suction prevention ring sheet 41 according to the first embodiment will be described mainly with reference to FIGS.

  In the dental handpiece 1 and the suction prevention ring sheet 41 of the first embodiment, when air is supplied from the intake pipe 13 through the intake port 14, the impeller 11 and tools (not shown) are ejected by the air. ) Is rotated to drive the trunk with the dental handpiece 1 and the head portion 2 is in a positive pressure state. As shown in FIGS. 3 and 5, the housing 5 is pressed against the inner bottom portion 5 a and comes into close contact with the inner bottom portion 5 a.

  On the other hand, in the dental handpiece 1 and the suction prevention ring sheet 41, when the above-described air injection is stopped, the impeller 11 continues to rotate for a certain time due to inertia.

  While the rotation of the impeller 11 due to the inertia continues, the air flow accompanying the rotation of the impeller 11 is discharged through the exhaust port 15 and the exhaust pipe line 16, and at the same time, near the air supply port 14 ( In the vicinity), the pressure decreases from “positive pressure” to “same pressure (relative to atmospheric pressure)” and from “same pressure” to “negative pressure”, and the entire inside of the head portion 2 changes to a negative pressure state. .

  In accordance with such a change in pressure from the positive pressure to the negative pressure in the head portion 2, a suction force acts on the suction prevention ring sheet 41 toward the lower surface of the bearing 24, and as a result, the suction prevention ring sheet 41. As shown in FIGS. 4 and 5, it moves while floating toward the lower surface of the bearing 24, closes the annular gap S1, and comes into close contact with the lower surface of the bearing 24.

  As a result, the invasion of a foreign substance such as a patient's saliva and blood from the bottom portion 22 side of the head portion 2 into the head portion 2 and further cut toothpaste is prevented, and the therapeutic action by the dental handpiece 1 is prevented. Thus, cross contamination between the patient and the operator and between the patient and the patient, which is likely to occur along with this, can be accurately prevented.

  More specifically, according to the dental handpiece 1 and the suction prevention ring sheet 41 of the first embodiment, the suction prevention ring sheet 41 does not contact the tool holding member 12. Can be improved in each stage.

  Accordingly, it is possible to prevent an increase in the invasion of foreign matters such as saliva and blood into the head portion 2 due to deterioration over time, and safety and reliability can be improved.

  In addition, in the case of the dental handpiece 1 and the suction prevention ring sheet 41 in the first embodiment, the air tightness is increased by the adhesion of oil even if oil adheres to the bearing lower surface due to negative pressure. Thus, the suction prevention ring sheet 41 can be more closely attached to the lower surface of the bearing 24 and the braking effect is increased. Since the suction prevention ring sheet 41 is floating, the spray oil easily enters the bearing 24. The suction prevention ring sheet 41 can prevent the turbine sound rotating at high speed from reverberating to the outside, and the suction prevention ring sheet 41 is made of an elastic material, so that the positive pressure in the head portion 2 and the negative pressure can be reduced. There are effects such as the fact that floating and bending can be executed reliably.

  Further, the suction prevention ring sheet 41 is made of a heat-resistant material such as Teflon (registered trademark), for example, so that it can be adapted to an autoclave.

  Furthermore, according to the first embodiment, the head cap 28 can be easily removed from the dental handpiece that has not taken countermeasures against the entry of foreign matter, and the suction prevention ring sheet 41 can be easily attached to a predetermined location in the head portion 2. Since it can be attached to a conventional product, it is also extremely effective as a measure for preventing foreign matter from entering a conventional product.

  Next, the dental handpiece 1 and the suction preventing ring sheet 41A according to the second embodiment of the present invention will be described with reference to FIGS.

  In addition, in the dental handpiece 1 and the suction preventing ring sheet 41A according to the second embodiment, the same elements as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The basic configuration of the dental handpiece 1 and the suction prevention ring sheet 41A according to the second embodiment is substantially the same as that of the first embodiment, but the external dimensions of the suction prevention ring sheet 41A are the same as the suction prevention ring sheet 41. And a lower surface of the retaining ring 33 in which the outer peripheral portion of the suction preventing ring sheet 41A is fixedly disposed in a seal part mounting recessed portion 24e below the outer ring 24 of the bearing 24, and It is characterized in that it faces the gap S3 between the inner bottom step portion 5b that supports the lower end surface of the outer ring 24 formed outside the inner bottom portion 5a.

  According to the dental handpiece 1 and the suction prevention ring sheet 41A according to the second embodiment, when the inside of the head part 2 is in a positive pressure state, the suction prevention ring sheet is the same as in the first embodiment. As shown in FIGS. 9 and 11, 41A is bent at the center side with its outer peripheral part facing the seal part mounting recess 24e, and is pressed against the inner bottom part 5a of the housing 5 to be brought into the inner bottom part 5a. It will be in close contact.

  On the other hand, when the inside of the head part 2 is in a negative pressure state, a suction force toward the lower surface of the bearing 24 acts on the suction prevention ring sheet 41A.

  Thereby, as shown in FIGS. 10 and 11, the suction preventing ring sheet 41A moves while floating in the lower surface direction of the bearing 24 with its outer peripheral part facing the seal part mounting recessed part 24e, It will be in the state contact | adhered to the lower surface of the bearing 24.

  That is, the central portion side of the suction preventing ring sheet 41A is in a state of closing the annular gap S1 and closely contacting the lower surface of the inner ring 24a.

  As a result, the invasion of a foreign substance such as a patient's saliva and blood from the bottom portion 22 side of the head portion 2 into the head portion 2 and further cut toothpaste is prevented, and the therapeutic action by the dental handpiece 1 is prevented. Thus, cross contamination between the patient and the operator and between the patient and the patient, which is likely to occur along with this, can be accurately prevented.

  According to the dental handpiece 1 and the suction prevention ring sheet 41 </ b> A according to the second embodiment, the same effects as in the first embodiment can be exhibited.

  Further, the suction prevention ring sheet 41A is made of an elastic material, and its thickness is thinner than the dimension in the length direction of the tool holding member 12 of the gap S3. At the same time, it is possible to reliably perform floating and bending at the time of negative pressure, and to reduce the obstruction to the air flow discharged from the bottom of the head portion 2 by reducing the thickness thereof as described above. it can.

  In this case, since the suction prevention ring sheet 41A may have a small vertical movement distance, the thickness thereof is made to be equal to or smaller than the gap dimension (for example, 0.15 mm) between the retaining ring 33 and the inner bottom step portion 5b. As a result, the annular gap S1 between the outer ring 24b and the inner ring 24a of the bearing 24 can be reliably closed or released in accordance with a change in the pressure in the head portion 2.

  Next, a further expansion example is outlined about the dental handpiece 1 and the suction prevention ring sheets 41 and 41A according to the first and second embodiments.

  In the dental handpiece 1 according to Example 1 described above, the suction prevention ring sheet 41 is moved toward the inner bottom portion of the housing 5, and the pressure in the head portion 2 becomes negative when the impeller 11 stops rotating. Thus, the suction preventing ring sheet 41 is moved toward the lower surface of the lower bearing 24 so as to be in close contact with the lower surface of the bearing 24, and an annular gap S1 between the inner ring 24a and the outer ring 24b of the bearing 24 is formed. By closing, the intrusion of foreign matter into the head portion 2 from the bottom side of the head portion 2 can be prevented, but instead, the upper surface of the bearing 29 located at the upper portion of the impeller 11 and the The suction-preventing ring sheet (not shown) disposed in a non-contact state with the tool holding member 12 so as to float in a gap region between the inner bottom portion of the holding bracket 31 positioned at the upper portion of the bearing 29 is provided. It can also be configured.

  According to this structure, when the impeller 11 is rotated, the pressure in the head portion 2 becomes a positive pressure, so that the suction prevention ring sheet 41 is moved toward the inner bottom portion of the bracket 31, and the impeller 11, when the rotation in the head 11 stops, the suction prevention ring sheet 41 moves toward the upper surface of the bearing 29 and is brought into close contact with the upper surface of the bearing 29. It is possible to prevent foreign matter from entering the head part 2 from the upper side of the head part 2 by closing the annular gap between the head part 2 and the head part 2.

  Furthermore, two suction prevention ring sheets 41 are used, between the bearing 24 and the inner bottom portion of the housing 5, and on the upper surface of the bearing 29 and the inner bottom portion of the holding bracket 31 positioned on the upper portion of the bearing 29. If the suction prevention ring sheets 41 are respectively disposed between the two, a foreign matter can be prevented from entering the head portion 2 from the bottom side of the head portion 2 and from the upper side of the head portion 2 to the head portion 2. It is possible to exert both the effects of preventing the intrusion of foreign matter, and to effectively prevent the invasion of foreign matter such as saliva and blood into the head portion 2, which is safe and reliable. Can be further improved.

  Further, in the case of the dental handpiece 1 according to Example 2 described above, the outer peripheral portion of the suction preventing ring sheet 41A is made to face the gap S3 when the pressure in the head portion 2 becomes negative. The suction prevention ring sheet 41A is moved toward the lower surface of the bearing 24 including the shield body 32 and the retaining ring 33 so as to be in close contact with the lower surface of the bearing 24, and an annular shape between the inner ring 24a and the outer ring 24b of the bearing 24 is provided. The gap S <b> 2 is blocked to prevent foreign matter from entering the head portion 2 from the bottom side of the head portion 2. Instead, the bearing 24 positioned above the impeller 11 and the bearing 24 are arranged. Arranged in a non-contact state with the tool holding member 12 so that it can float in a gap region between the upper surface of the bearing 29 having the same structure and the inner bottom portion of the holding bracket 31 positioned above the bearing 29. It may be configured to include the illustrated without the suction preventing ring sheet.

  If comprised in this way, when the impeller 11 rotates, the pressure in the head part 2 becomes a positive pressure, whereby the suction prevention ring sheet 41A is restrained and moved toward the inner bottom of the bracket 31, and the impeller 11, when the pressure in the head portion 2 becomes negative, the suction prevention ring sheet 41 </ b> A moves toward the upper surface of the bearing 29 and is brought into close contact with the upper surface of the bearing 29. It is possible to prevent foreign matter from entering the head part 2 from the upper side of the head part 2 by closing the annular gap between the head part 2 and the head part 2.

  Further, two suction prevention ring sheets 41A are used, and between the bearing 24 and the inner bottom portion of the housing 5, as well as the upper surface of the bearing 29 and the inner bottom portion of the holding bracket 31 positioned at the upper portion of the bearing 29. If the suction prevention ring sheet 41A is disposed on both sides of the head portion 2, foreign matter can be prevented from entering the head portion 2 from the bottom side of the head portion 2, and from the upper side of the head portion 2 to the head portion 2. It is possible to exert both the effects of preventing the intrusion of foreign matter, and to effectively prevent the invasion of foreign matter such as saliva and blood into the head portion 2, which is safe and reliable. Can be further improved.

  The suction prevention ring sheets 41 and 41A are not illustrated in addition to those described above, but may have a shape in which a plurality of concentric convex portions having a predetermined interval are provided on the surface, or an outer peripheral portion on the surface from the center side. A shape in which a plurality of convex portions are provided in a radial form can be used.

  By providing a plurality of concentric convex portions on the surfaces of the suction prevention ring sheets 41 and 41A, the outer diameter side corner portion (small R chamfering) of the inner ring of the bearing serving as the contact portion is provided on the outer diameter side. The concentric convex portions of the suction preventing ring sheets 41 and 41A are in a surface contact state so as to wrap around the corner portion, thereby improving the braking performance when the impeller 11 is stopped.

  The present invention is not limited to a dental handpiece, and in various medical devices that use air to drive tools, it is possible to reduce the cause of infection due to foreign matter intrusion into the head of the device, It can be widely used as a safety improvement measure.

DESCRIPTION OF SYMBOLS 1 Dental handpiece 2 Head part 3 Main body part 4 Hose joint 5 Housing 5a Inner bottom part 5b Inner bottom step part 11 Impeller 12 Tool holding member 13 Air supply line 14 Air supply port 15 Exhaust port 16 Exhaust pipe 21 Push cap 22 Bottom 23 Clearance 24 Bearing 24a Inner ring 24b Outer ring 24c Ball 24d Retainer 24e Sealing part mounting recess 26 O-ring 27 O-ring 28 Head cap 29 Bearing 30 Spring 31 Holding bracket 32 Shield body 32a Outer part 32b Central part 33 Retaining ring 41 Ring sheet 41A Suction prevention ring sheet 42 Central hole S1 Annular gap S2 Gap area S3 Gap

Claims (6)

A tool holding member that rotatably supports the impeller in the head portion by a bearing and holds a required tool via the impeller by air jetted from an air supply port formed in the head portion. A dental handpiece that rotationally drives a member and exhausts the air from an exhaust port formed in the head portion,
The lower surface and upper surface of each bearing located at the lower and upper portions of the impeller in the head portion, the housing constituting the head portion located at the lower and upper surfaces of each bearing, and the inner bottom portions of the holding brackets Including one or two suction prevention ring sheets that are floatable in one or both of the gap regions between them and arranged in a non-contact state with the tool holding member;
When the pressure in the head portion becomes positive during the rotation operation of the impeller, the one or two suction prevention ring sheets are moved to one or both of the inner bottom portions of the housing and the holding bracket,
When the rotation of the impeller is stopped, the pressure in the head portion becomes negative, so that the one or two suction prevention ring sheets are placed in one or both of the lower surface direction of the lower bearing and the upper surface direction of the upper bearing. To the lower surface of the lower bearing, the upper surface of the upper bearing, or both, and an annular gap between the inner ring and the outer ring of the lower bearing, the inner ring and the outer ring of the upper bearing It is configured to prevent entry of foreign matter into the head part from one or both of the bottom side of the head part and the top side of the head part by closing one or both of the annular gaps between them. Dental handpiece. A tool holding member that rotatably supports the impeller in the head portion by a bearing and holds a required tool via the impeller by air jetted from an air supply port formed in the head portion. A dental handpiece that rotationally drives a member and exhausts the air from an exhaust port formed in the head portion,
The lower surface and upper surface of each bearing located at the lower and upper portions of the impeller in the head portion, the housing constituting the head portion located at the lower and upper surfaces of each bearing, and the inner bottom portions of the holding brackets A seal component that is floatable in one or both of the gap regions between them and is arranged in a non-contact state with the tool holding member, and has an outer peripheral portion fixed to an inner peripheral portion of the lower or upper outer ring of each bearing. One or two suction preventions facing the gap between the lower surface or the upper surface of the head and the inner bottom portion of the head or the inner bottom step portion of the housing that supports the lower end surface of the outer ring formed on the holding bracket With a ring seat,
When the impeller rotates, the pressure in the head portion becomes a positive pressure, so that the suction prevention ring sheet is placed on the lower portion with the outer peripheral portion of the one or two suction prevention ring sheets facing the gap. Move to one or both of the lower surface direction of the bearing, the upper surface direction of the upper bearing, and closely contact one or both of the lower surface of the lower bearing, the upper surface of the upper bearing,
When the rotation of the impeller is stopped, the pressure in the head portion becomes negative, so that the one or two suction prevention ring sheets are faced toward the lower surface of the lower bearing with the outer peripheral portion facing the gap. , Moved to one or both of the upper bearings in the upper surface direction, and brought into close contact with one or both of the lower face of the lower bearing and the upper face of the upper bearing, and the ring located between the inner ring and the outer ring of the lower bearing By closing one or both of the gap and the annular gap between the inner ring and the outer ring of the upper bearing, foreign matter intrudes into the head part from one or both of the bottom side of the head part and the upper side of the head part. A dental handpiece characterized in that it can be prevented.   The suction prevention ring sheet according to claim 1, wherein the suction prevention ring sheet is made of an elastic material.   The suction prevention ring sheet according to claim 2, wherein the suction prevention ring sheet is made of an elastic material, and the thickness thereof is thinner than the dimension of the gap in the length direction of the tool holding member.   The suction prevention ring sheet for a dental handpiece according to claim 3 or 4, wherein the suction prevention ring sheet is made of a heat-resistant material.   The suction prevention ring sheet for a dental handpiece according to any one of claims 3 to 5, wherein the suction prevention ring sheet has a shape in which concentric convex portions are provided on a surface thereof.

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