A dental syringe

Abstract: A dental syringe envisages heating means (11) consisting of a heating element (12) positioned inside an air tube (7) and a block (13) positioned between a distributor nozzle (4) and the heating element (12); the block (13) houses part of a water tube (8) which is set parallel with and close to the heating element (12); the block (13) also houses means (5) for the activation of the fluid supply and a second air tube (14) for the passage of warm air from a first tube (7) to a valve (15), also inside the block (13), the valve allowing the air access to a first open chamber (16) which is opposite a flexible element (17) which separates the first chamber (16) and the first water tube (8) which exits from the opposite side of the first chamber (16), the partition (17) being designed to allow heat exchange between the two fluids; the partition (17) and valve (15) also form the means (5) for the activation of the water supply from the first tube (8) to the distributor nozzle (4).

Description: The present invention relates to a dental syringe. It is known that such a handpiece is used by the dentist using water (or a physiological solution) or air or a nebulized mixture of both, to clean or dry the area of the patient's mouth to be worked upon. Such a syringe (see also European patent EP - 622.054) currently consists of a grip with a tubular body housing the mechanical, hydraulic and electrical parts designed to supply water and air. The front end of this tubular body is closed by a distributor nozzle for the afore-mentioned fluids, which may be connected to the feed unit using removable fixing means (so that it may be substituted while it is sterilized) and the back is closed by an external connector connected to the compressed air and water supply from the dental unit. The outer surface of the tubular body also has two reference projections, these being the pushbuttons which activate, directly or by means of lever systems, the respective water and air cut-off valves, allowing the dentist to select the desired fluid supply. The syringe may also house an independent bulb which allows a band of light to be formed around the fluid supply zone. A closer examination of the technical details reveals that the said independent water and air tubes run the length of the unit to the nozzle, the tubes being fitted with the said valves at an intermediate point, so as to allow the supply of the relative fluid only when required. The tubes may also be fitted with heating elements to heat the fluids which pass through them so that the fluids are supplied at the correct temperature for the patient; the heating elements can normally be activated when the syringe is removed from its support on the dental unit, or using a purpose-designed control on the grip of the syringe. Patent US 4,886,452, which is considered the closest state of the art, shows a dental spray handpiece, consisting of a gripping sleeve having a media inlet connection at one end thereof and a media discharge at the other end. In the sleeve there are arranged two media conduits, of which one is connected to a air source and the other to a water source, and each of conduits has associated therewith a respective electrical heating device with an associated heating current circuit for the heating of each medium. However, modern dental units are equipped with a heated water tank (often filled with common drinking water) fitted inside the base of the unit itself and used, for example, to fill the rinsing tumbler or supply the various operating handpieces or accessories, reducing the patient's discomfort as far as possible. Despite this, syringes continue to be produced with twin heating elements, for the air and water, partly to standardize the product, since it is impossible to know at the production stage the type of dental unit to which the product will be fitted (with or without heated tank): this factor obviously makes the dental syringes currently produced more expensive and cumbersome. For this reason, the Applicant has designed and created a dental syringe of simple construction, economical, technically and practically specialized and suitable for use on dental units equipped with a heated water tank. The technical features of the present invention, in accordance with the said aims, are clearly described in the claims herein and the advantages of the invention are more clearly shown in the detailed description below, with reference to the accompanying drawings which illustrate an embodiment by way of example only, and in which: figure 1 is a side view of the dental syringe disclosed, with some parts shown in cross-section along a vertical plane of the syringe to better view others; figure 2 is a plan view of the dental syringe illustrated in figure 1, with some parts shown in cross-section to better view some of the details inside the syringe; figures 3 and 4 show cross-sections III - III and IV-IV shown in figure 1; figure 5 is a side section of the front part of the syringe disclosed, scaled-up with respect to figure 1. In accordance with the accompanying drawings, and in particular with reference to figures 1 and 2, the dental syringe disclosed is one of a set of handpieces used on dental units, and in particular is used to clean the patient's mouth during treatment. This syringe includes a central grip 1 consisting of a tubular body 2 which houses a unit 3 for the selection and supply of water (or physiological solution) and air: the front end of the tubular body 2 is fitted with a distributor nozzle 4, while the back of the unit 3 can be fitted with a connector 6 for the supply of the said fluids under pressure. The number 5 denotes means for the activation of the supply of the fluids which pass through the unit 3 and are described in further detail below, whilst the unit 3 includes a pair of first tubes 7 and 8, which run parallel to one another as far as the distributor nozzle 4. Both the means 11 for heating the passing fluids and the afore-mentioned supply activation means 5 operate on the pair of tubes 7 (air) and 8 (water), so that one or both may be supplied at a suitable temperature. The structure of the syringe also envisages lighting means 18 for the operating zone through which the fluids pass to the distributor nozzle 4 (also described in further detail below). Still observing figures 1 and 2, the heating means 11 consist of a single heating element 12 positioned inside the air tube 7 and of a block 13 located between the distributor nozzle 4 and the said heating element 12. This block 13 contains part of the water tube 8, the LONGER PART of this tube lying outside the block 13, parallel with and close to the heating element 12, and the afore-mentioned fluid supply activation means 5. The block 13 also houses a second air tube 14 for the passage of pre-heated air from the tube 7 to the valve 15 (described. in detail below), said valve also being located inside the block 13. This valve 15 (visible in figure 4) allows air to pass into a first open chamber 16 set opposite a flexible element 17 which forms a partition between the first chamber 16 and the afore-mentioned first water tube 8 which extends in a "C" shape inside the block 13 and exits at the opposite side of the first chamber 16; the partition 17 also extends to separate the block 13 into two sectors and is made of a material which allows heat exchange between the two fluids. As is more clearly shown in the following text, the partition 17 and the valve 15 also form the said means 5 for activation of the water supply from the first tube 8 to the distributor nozzle 4. In particular, the valve 15 consists of a seat 24 inside the block 13, into which a basic element 25 is screwed to form a seal, opposite a ring 26 with a central narrow opening 27 for the passage of air from the second tube 14 to the first chamber 16. The water supply activation means 5 consist of a mobile pushbutton 19 located on and projecting into/from the block 13 (so that it can be operated from the exterior by applying pressure to the sleeve 10 of the tubular body 2). The pushbutton 19 is positioned opposite, but does not make contact with, a fixed sealed base 20 so as to define a second transit chamber 21; the two elements are, in fact, separated by a flexible element 22 (a spring) designed to hold the pushbutton 19 in a raised position in which the passage of water is not activated. The valve 15 gives onto the second chamber 21, connecting the latter to the first chamber 16 which holds the air and extends perpendicular to the position of the pushbutton 19 on the block 13: in this way, when the pushbutton 19 is pressed down a vacuum is created which allows the air to exit the latter, with relative flexing of the partition 17 (under the force of the water pressure) towards the first chamber 16, so that the water passes first into a bend created by the flexing of the partition 17, then into a third tube 23 parallel to the first tube 8, and extending into the distributor nozzle 4 (see arrow F in figure 1). Similarly, the air supply activation means 5 (visible in figure 3) consist of a pushbutton 40 set opposite a basic sealing element 41, held apart by a spring 42; in the embodiment illustrated, when the pushbutton 40 is pressed down, it allows air to pass directly from the first tube 7 to a third tube 43 which extends towards the distributor nozzle 4 (see arrow F2 in figure 4). As is clearly visible in figure 5, the said third water tube 23 may be fitted with a one-way shutoff valve 62 (non-return valve); this valve 62 may be mechanical (as illustrated), that is to say, consisting of a spring 63 which acts upon a spherical stopper 64 or similar element, housed axially inside the third tube 23: in this way, should the air pressure in the first chamber 16 and so also on the partition 17 be absent for any reason, a column of water, whose pressure is discharged through suitable vents in the dental unit, is prevented from flowing out of the tubes in the distributor nozzle 4 and causing leaks. Figure 5 also clearly illustrates the distributor nozzle 4 of the syringe disclosed, said distributor nozzle consisting of two distinct elements which can be fitted together: one is a fitting 28 with curved cross-section, which can be secured to the end of the tubular body 2 and connected and sealed directly to the block 13; this fitting houses the afore-mentioned third tubes 23 and 24 which connect the first tubes 7 and 8 and the fifth tubes 29 located inside a second end element 30 which defines a distributor nozzle 4. This end element 30 rotates freely about its own axis X and can be detached from the fitting 28; the end element 30 houses the afore-mentioned lighting means 18, which are secured to an internal support 31 that can be removed together with the end element. In the embodiment illustrated in figure 5, the lighting means 18 consist of an incandescent bulb 32 fitted in a seat 33 on the internal support 31 and axially offset relative to the axis X of the end element 30. The back of the bulb 32 is connected to a double ring conductor 34 (which is, in turn, connected to a power source not illustrated) by means of a pair of contacts 35; the latter are flexibly held in constant contact with the double ring 34 so that the bulb 32 is supplied with power when the second end element 30 rotates. The double ring conductor 34 is also axially secured to a second, sealed, ring 37 fixed directly to the fitting 28. A cable of optic fibres 36 is connected to the bulb 32, extending from the front of the bulb itself to the open distributor end of the end element 30, so as to create a band of light directly in the spray zone. The bulb 32 is also fitted with cooling means 60, consisting of a sixth air tube 61 for the passage of air from the connector 6, where it connects with air supply channels on the dental unit (not illustrated here, since they are of the conventional type), into the said block 13 through a tube in the block which is not visible in figures 1 and 2 because it lies in a different plane, then giving onto a seventh tube 61a (similar to the third tube 23) connecting it to the distributor nozzle 4 (see arrow F1 in figures 1 and 5). Here the air passes through a gap 65 in the support 31 parallel to the fifth tubes 29, then gives onto the bulb 32 through a hole 66. The air, having cooled the bulb and become warm, is discharged through gaps (formed from the conventional connection of the elements which constitute the distributor nozzle). The syringe structured in this way operates through the activation of the afore-mentioned pushbuttons 19 and 40, which allow the passage of the fluids under pressure from the first tubes 7 and 8 to the distributor nozzle 4, either separately or in a nebulized mixture. The syringe is disassembled for sterilization by the rapid removal of the tubular body 2 secured to the distributor nozzle 4 from the unit 3. In particular, the distributor nozzle 4 can be disassembled (as is clearly shown in figure 5) by detaching the end element 30 from the fitting 28, after which it is possible to substitute the bulb 32. The syringe therefore obtains the objects set, thanks to a compact, technically advanced structure, since the air and water are sufficiently heated by the single heating element and the block 13 with partition 17, which allow a good heat-exchange between the air and water without necessitating other internal heating elements. The supply of water or physiological solution is activated by a pneumatic control (preferable due to its precision and fast activation) by means of the valve connected to the air tube under pressure and to the partition: such a structure is preferable to a direct water control, since direct valves are not recommended for contact with a physiological solution, which causes the formation of scale. The present invention may be subject to numerous modifications, all encompassed by the original design concept, and all parts may be substituted with technically equivalent components.

Claims: A dental syringe of the type which includes a central grip (1) including a tubular body (2) which houses a unit (3) for the selection and supply of water and air to an distributor nozzle (4) connected to the said unit in such a way that it may be removed at the front end of the tubular body (2), the latter also housing air and water supply activation means (5) which act upon the said unit (3), in turn connected to a connector (6) for the supply of the said fluids to the unit (3); the latter also having at least a pair of first tubes (7, 8) practically parallel to one another and exiting the said distributor nozzle (4); fluid heating means (11) and the said air and water supply activation means (5) acting upon the first tubes (7, 8) to allow the said fluids to be supplied individually or mixed together at a suitable temperature; said syringe also having lighting means (18) at the operating zone defined by the supply of the said fluids to the distributor nozzle (4), characterized in that it envisages the said heating means (11), consisting of at least one heating element (12) positioned inside the air tube (7) and a block (13) fitted between the distributor nozzle (4) and heating element (12) and housing a first part of the water tube (8), a second part of this tube lying outside the block (13), parallel with and close to the heating element (12); said block (13) housing the supply activation means (5) and a second air tube (14) for the passage of air from the relative tube (7) to a valve (15), also being located inside the block (13), allowing air to pass into a first open chamber (16) set opposite a flexible element (17) which forms a partition between the first chamber (16) and the first water tube (8) which exits at the opposite side of the first chamber, the partition (17) being made of a material designed to allow heat exchange between the fluids; the partition (17) and the valve (15) also forming part of the said means (5) for activation of the water supply from the first tube (8) to the distributor nozzle (4). The dental syringe as described in claim 1, characterized in that the said water supply activation means (5) consist of a mobile pushbutton (19) located on and projecting into/from the block (13) and positioned opposite a lower fixed, sealed base (20) so as to define a second transit chamber (21); the base (20) and pushbutton (19) being separated by a flexible element (22) designed to hold the pushbutton (19) in a raised position in which the passage of water is not activated; the first chamber (16) which holds the air and extends perpendicular to the position of the pushbutton (19) giving onto the second chamber (21), so that when the pushbutton (19) is pressed down a vacuum is created which allows the air to exit the latter, with relative flexing of the partition (17) towards the first chamber (16), so that the water passes into a third tube (23) substantially parallel to the first tube (8), and extending into the distributor nozzle (4). The dental syringe as described in claim 1, characterized in that the valve (15) consists of a seat (24) inside the block (13), into which a basic element (25) is screwed to form a seal, opposite a ring (26) with a central narrow opening (27) for the passage of air from the second air tube (14) to the first chamber (16). The dental syringe as described in claim 1, characterized in that the distributor nozzle (4) consists of two distinct elements, one being a fitting (28) with curved cross-section, which can be secured to the end of the tubular body (2) and connected to the block (13) and having third tubes (23) which connect the first tubes (7, 8) and the fifth tubes (29) located inside a second end element (30) which defines the actual distributor nozzle (4), rotating freely about its own axis (X) and which can be detached from the fitting (28); the end element (30) housing the lighting means (18), which are secured to an internal support (31) that can be removed together with the end element. The dental syringe as described in claim 4, characterized in that the lighting means (18) consist of an incandescent bulb (32) fitted in a seat (33) axially offset relative to the axis (X) of the end element (30) on the internal support (31); the back of the bulb (32) being connected to a double ring conductor (34) which is flexibly held in constant contact with the double ring (34) so that the bulb (32) is supplied with power when the second end element (30) rotates; the double ring conductor (34) being, in turn, secured to a second, sealed ring (37) fixed directly to the fitting (28). The dental syringe as described in claim 5, characterized in that the bulb (32) is fitted with a cable of optic fibres (36), extending from the front of the bulb itself to the open distributor end of the second end element (30). The dental syringe as described in claim 1, characterized in that the lighting means (18) are fitted with cooling means (60), consisting of a sixth air tube (61) for the passage of air from the connector (6), through the block (13) and giving onto the distributor nozzle (4) at a bulb (32) which forms the said lighting means (18). The dental syringe as described in claim 2, characterized in that the third water tube (23) is fitted with a one-way shutoff valve (62) which acts upon the third tube, preventing the passage of water from the first tube (8) to the said third tube (23) should the air pressure in the first chamber (16) and on the partition (17) be absent. The dental syringe as described in claim 1, characterized in that the partition (17) extends to separate the block (13) into two sectors and is made of a material which allows heat exchange between the two fluids.

Inventors: CASTELLINI FRANCO, CASTELLINI, FRANCO
Applicants: CASTELLINI SPA, CASTELLINI S.P.A.
Application year: 1995
Main classification: A61C17
IPC codes: A61C17, A61C1