BACKGROUND OF THE INVENTION

1. Field of the Invention:

The present invention is directed to a dental tool handle and method for making the same. More particularly, the present invention is directed to a dental tool handle that prevents seepage of contaminants into an interior of the handle.

2. Discussion of Related Art:

Dental tools with attachable tool heads are known. Such tools typically include a hollow handle with, for example, a tapered swedged end having an opening. For dental tools with tool heads on both sides, the handle would have two tapered heads and openings, one at each end.

Conventionally, a pin forming the base of the dental tool head is inserted into the handle opening and then fixed to the handle around the periphery of the opening, such as by press-fit, adhesive, welding, or other known methods.

A conventionally assembled dental tool 100 is shown in Fig. 1 1 and includes a longitudinally extending hollow handle 1 10, typically formed of surgical steel, or other metal suitable for surgical instruments. The handle 1 10 typically has a tapered portion 1 12 that is formed by, e.g., swaging, to yield a portion of the handle having a smaller diameter than that of the main body of the longitudinally extending hollow handle 1 10.

In prior art dental tools, the tool is assembled by press-fitting a tool head 124, having a functional portion 125, which may be shaped, for example, to facilitate scraping or probing of the teeth, and an insertion pin 126. To assemble the conventional dental tool 100, the insertion pin is press fit into an opening that has been formed at the tapered end of the handle 1 10. Fig. 1 1 shows the pin in the fully inserted position. Typically, the pin 126 is welded and/or affixed with an adhesive into the opening at the tapered end.

However, dental tools assembled in this conventional way by press fitting a pin of the tool head into a swedged end of the handle can be subject to certain problems. In particular, they are subject, over time, to seepage of pathogens, for example, into the handle. Specifically, in the conventional tool the handle of the dental tool is often manufactured from a different material, e.g., a different metal, than that of the pin of the tool head. Due to such differences in material, there is often a corresponding difference in the thermal expansion coefficients between these two materials.

Dental tools are usually cleaned in an autoclave which uses high temperatures to disinfect the tools. In particular, an autoclave uses steam under high pressure to kill pathogens that may accumulate on the tool by the use of the tool on a patient. Because of the different thermal expansion coefficients between the handle and tool head, pathogens and/or other residuals from previous use can seep into parts of the tool that are not reached by the high pressure steam, such as the interim of the handle. This can occur, for example, when a gap is present, e.g., between the pin of the tool head and the neck of the opening, that leads to a part of the tool. When this occurs, pathogens from one patient may still be present for the next patient, which may potentially spread disease from one patient to another.

Due to the use of materials of different thermal coefficients of expansion, and wear and use of the tool, conventional dental tools are particularly susceptible to the formation of gaps at the portion at which the tool head pin is welded or affixed to the opening in the tapered portion of the handle. Thus, there is a need for a dental tool, and method of manufacturing such a tool, that eliminates the formation of gaps that may provide access of residuals to areas unreachable by the autoclave disinfecting process.

SUMMARY OF THE INVENTION

The present invention is directed to a dental tool handle that prevents seepage of contaminants or residuals into the interior of the main body portion of the handle. In accordance with an embodiment, an insert is fitted into an opening at one or both ends of the handle and then welded securely into the opening. A channel or bore is then formed in the insert along the longitudinal axis of the handle into which a base of a dental tool can be inserted. In a method for manufacturing the dental tool handle of the present invention, the insert is fitted into an end of the handle, welded in place, and then a boring operation is performed to yield a space for receiving a base of the dental tool. Finally the base of the dental tool is fitted into the channel. It should be noted that an insert can be fitted on each end of the handle to accommodate a different tool on each end ("two-sided"), or just on one side for a single tool ("single-sided").

In accordance with one aspect of the present invention, a substantially cylindrical insert, for example one or more stainless steel dowel pins, are positioned in an opening at one or both ends of the handle and then welded securely therein. The dowel pin ("dowel") is then drilled after the welding to the handle to form a channel in the dowel pin itself. The base pin of the dental tool is then press fitted into the channel formed in the dowel pin, rather than being inserted directly into the handle opening.

According to another aspect of the present invention, a method for forming a dental tool having a tool head and a hollow handle, the tool head having a pin portion and a functional portion, includes: press-fitting a dowel into an end opening of the hollow handle until a face at a longitudinal end of the dowel is aligned with the end opening of the hollow handle and the longitudinal extent of the dowel is arranged within the hollow handle; affixing the press-fitted dowel to the hollow handle; forming a channel in the longitudinal end of the dowel, such that the channel extends at least partially within the hollow handle when the dowel is positioned in the hollow handle end opening, the channel having a diameter less than a diameter of the end opening of the hollow handle; and inserting the pin portion of the tool head into the channel formed in the longitudinal end of the dowel to securely seat the pin portion of the tool head into the channel formed in the longitudinal end of the dowel so that the functional portion extends beyond the end of the handle. In another aspect, the dowel is affixed to the hollow handle by at least one selected from the group consisting of a welding and an adhesive.

In another aspect, the channel in the longitudinal end of the dowel is formed by a drill press.

In another aspect, the hollow handle has a tapered end in which the end opening is formed.

In another aspect, the tapered end is formed by swaging of the hollow handle.

In another aspect, the pin portion of the tool head is inserted into the channel formed in the longitudinal end of the dowel by a pressing station.

In another aspect, the hollow handle is made of stainless steel.

In another aspect, the method further includes, prior to the press-fitting step, forming the end opening of a hollow handle using a drill press.

In another aspect, the dowel is made of steel having substantially identical characteristics as the steel of the hollow handle.

According to yet another aspect of the present invention, a dental tool includes: a hollow handle having an open end, the hollow handle having a first channel along at least a portion of its longitudinal extent; a dowel fixedly arranged within the first channel such that a face at a longitudinal end of the dowel is aligned with the end opening of the hollow handle, the longitudinal extent of the dowel being arranged within the hollow handle; the dowel having a second channel, having a smaller diameter than the first channel, formed in the longitudinal end of the dowel; and a tool head, having a functional portion and a pin portion, the pin portion of the tool head being fixedly arranged in the second channel to securely seat the pin portion of the tool head into the second channel so that the functional portion extends beyond an end of the handle.

In another aspect, the dowel is affixed to the hollow handle by at least one selected from the group consisting of a welding and an adhesive.

In another aspect, the hollow handle has a tapered end in which the end opening is formed.

In another aspect, the hollow handle is made of stainless steel.

In another aspect, the dowel is made of steel having substantially identical characteristics as the steel of the hollow handle. BRIEF DESCRIPTION OF THE DRAWINGS

The Figures are described as follows:

Figs. 1 and 2A are perspective views showing the drilling of an opening into a swedged end of the handle, in accordance with an embodiment of the present invention;

Fig. 2B is a partial cross-sectional view showing the drilled opening from Figure

2A;

Figs. 3 and 4 are perspective views showing the installation of the stainless steel dowel pin into the drilled swedged end of the handle, in accordance with an embodiment of the present invention;

Figs. 5 and 6 are perspective views showing the welding of the inserted stainless steel dowel pin into the swedged end of the handle, in accordance with an embodiment of the present invention;

Figs. 7 and 8A are perspective views showing the drilling of a channel into the exposed surface of the dowel pin, in accordance with an embodiment of the present invention;

Fig. 8B is a partial cross-sectional view of the tip portion of the handle after the drilling of the channel in the dowel pin, in accordance with an embodiment of the present invention;

Figs. 9 and 10A are views showing the insertion of the pin of the tool head into the channel of the dowel pin, to form the completed dental tool according to the present invention;

Fig. 10B is a cross-sectional view of the assembled dental tool in accordance with the present invention; and

Fig. 1 1 is a cross-sectional view showing a conventional dental tool.

DETAILED DESCRIPTION OF THE CURRENTLY PREFERRED EMBODIMENTS

With reference to Figs. 1 , 2A and 2B, a step in the formation of the dental tool handle 1 in accordance with an aspect of the present invention is forming an opening at a tapered swedged end of the handle 1 . The handle 1 is formed generally of a longitudinally extending substantially hollow portion 10 of a first diameter, and a tapered end 12 that has been tapered in a known manner, e.g., by swaging. The tapered end 12 extends to a tip 14 having a second diameter, less than the first diameter.

The handle 1 is preferably made of a stainless steel or other material of a type suitable for surgical instruments, such as 303 stainless steel, although not limited to this type of steel. Next, an opening 14a is formed in the tip 14 with a drill press 16.

Alternatively, in the case of a tapered handle formed with an opening already present, the steps shown in Figures 1 and 2 can be omitted. The opening 14a in the tip 14 can be seen clearly in the partial cross-sectional view of Fig. 2B.

Once the opening 14a has been formed, a dowel pin 18, preferably made of the same metal as the handle 1 , e.g., stainless steel, is press fit into the opening 14a, as shown in Figures 3 and 4. The dowel pin 18 has a length in the axial direction and is inserted as shown by the directional arrow. Preferably, after the press fitting of the dowel pin 18, the face of the dowel pin 18 substantially aligns with the end opening 14a, as can be seen in Fig. 4, leaving the main longitudinal extent of the dowel pin 18 lodged within the neck of the swedged tapered end 12.

To ensure the dowel pin (or "dowel") 18 is securely affixed to the swedged tapered end 12, as shown in Figs. 5 and 6, a welding instrument 20, preferably of the type that performs TIG welding, welds the dowel pin 18 to the walls of the tapered end 12 that were formed in the drilling described above with respect to Figs. 1 , 2A and 2B, or which may have already been present in the handle. The welding ensures that the dowel pin 18 is securely affixed to the handle and will not move in subsequent assembly steps, or during the use of the dental instrument. The tip after the welding step is represented by reference numeral 14b. Adhesive may be used in addition to the welding to even more securely affix the dowel pin 18 within the opening of the handle.

Next, as shown in Figs. 7, 8A and 8B, a channel 14c, having a diameter smaller than the previously drilled opening 14a and a length less than the length of the dowel pin 18, is formed in the dowel pin 18, such as by for example, using drill 22. Fig. 8B is a partial cross-sectional view showing the dowel pin 18, after having been welded to the walls of the tapered end 12, with a channel 14c having been formed by the drilling operation of the drill 22.

The outer surface of handle 10 of the dental tool 1 will preferably be treated so as to form grooves and/or raised portions, e.g., by knurling. The steps of forming such grooves and/or raised portions is not part of the present invention, and such features provide a more secure grip for the user of the instrument, as well as a distinctive appearance to the dental tool. For the purposes of this application, the function of such grooves and/or raised areas is to improve the grip of the user. It is noted that while the figures do not show the presence of such features until after the drilling shown in Figs. 7, 8A and 8B, these finishing steps can be performed earlier in the process and the invention is not limited to delaying the finishing until after the drilling step of Figs. 7, 8A and 8B.

Figs. 9 and 10A show the insertion of the tool head 24, having a functional portion 25, which may be formed to facilitate scraping of the teeth, or probing the teeth, and a pin 26 configured to be insertable into the tapered end 12 of the handle. As shown in Figs. 9 and 10A, the pin 26 of the tool head 24 is press fit into the channel 14c, using, for example, a pressing station, to form the completed dental instrument. Fig. 10B is a cross-sectional view showing the pin 26 securely seated in the channel 14c to complete the process.

The present invention forms a secure dental instrument in which the pin of the tool end is securely affixed into a channel in a dowel pin that has been welded securely into the handle. By virtue of this advantageous structure, the pin of the tool end interfaces securely with the channel in the dowel pin, and does not directly interface with the handle itself. Thus, in the event there is any fluid seepage, such seepage is contained within the dowel pin channel and will not extend into larger diameter portion, or main portion, of the tool body.

By, for example, using a steel for the dowel pin having the same characteristics as that of the handle, and by welding the dowel pin securely within the handle, this interface between the tool head and the tool handle will remain secure even after many uses, even in the presence of temperature changes such as those which are associated with autoclave disinfection. Such secure connection will prevent the occurrences of gaps that could allow residuals to enter the handle of the dental tool.

Moreover, by arranging the pin of the tool head in a channel that does not lead into the hollow portion of the handle, any contamination that may make its way past the pin of the tool head will be limited to the channel, which is completely separated from the hollow portion of the handle itself.

Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.