Abstract:
A dental apparatus or instrument includes a hollow, tubular metal handle, closing members fastened to opposite open ends of the handle, and tool parts connected to the closing members. The metal handle includes a central substantially smooth region and two surface contoured regions adjacent to the closing members. The surface contoured regions include wide grooves in a criss-crossed pattern superimposed on V-shaped narrow grooves in a criss-crossed helical pattern. The combination of the two type grooves gives a sure grip feel to the two surface contoured regions. The closing members each include an attachment portion which tightly interfits into an open end of the handle and which is brazed into the handle.

Description:
FIELD OF THE INVENTION 
     The present invention relates to dental instruments, particularly hand-held dental instruments having an elongated body with tools carried on one or both ends of the elongated body. Particularly, the invention relates to a hand-held dental instrument having a metal handle with metal tool receptacles on opposite ends thereof for the fixation of tools to the handle. 
     BACKGROUND OF THE INVENTION 
     Dental instruments having an elongate metal handle carrying one or two tool parts are known, such as disclosed in U.S. Pat. Nos. 2,818,647 or 4,060,897. U.S. Pat. No. 2,818,647 discloses an instrument having a shank which includes a socket portion which serves as a recessed seat for holding a tool or blade member by a wedge fit. U.S. Pat. No. 4,060,897 discloses a tool having a handle section which threadedly receives a tool section, or the handle section merges into a neck portion which integrally merges into a serrated surface section. The instruments disclosed in these two patents include handle regions having gripping serrations or grooves axially aligned with the handle for enhancing gripping of the instrument. 
     The present invention recognizes the desirability of providing an instrument handle with an improved gripping surface, and also a handle which can accommodate one or two tool parts into one or both opposite ends, respectively, in a secure and aesthetically pleasing manner. 
     SUMMARY OF THE INVENTION 
     The present invention contemplates a dental apparatus which includes a tubular, hollow metal handle having first and second ends with an exterior peripheral surface therebetween. The apparatus includes first and second closing members wherein each member includes an attachment portion. Each of the attachment portions slidably engages a hollow end of the handle and is metallically bonded, without adhesive, to at least one adjacent region of the respective end. 
     The handle is scored with at least a first single helical grip enhancing pattern. The scoring can exhibit a substantially narrow V-shaped cross section. The scoring is preferably formed with a metal cutting tool having a pointed end. 
     The handle can also be scored with a second single helical grip enhancing pattern displaced from the first pattern. The scoring of the second pattern can have a substantially rectangular cross section. The second pattern can be formed with a metal cutting tool with a wide, flat end. Preferably, the first and second patterns are each criss-crossed double helical patterns. 
     Each of the closing members can include a tapered, exterior body portion or cone portion displaced from a respective attachment portion. The attachment portions can each include an undercut region to facilitate bonding with the handle. A brazing compound or paste initially deposited inside the end regions of the handle, flows under capillary action into the undercut regions when melted by heating the instrument in a vacuum oven. The cone portion can include an implement receiving recess. 
     An implement or tool part can be press fit and/or secured with an adhesive in the implement receiving recess. The adhesive is cured when the instrument is heated in an oven. 
     Alternatively, a closing member can be attached to one end of the handle, the handle carrying a single tool. The respective other end can be closed by other means such as by an alternate closing member having an end cap. The alternate closing member can have an attachment portion which is formed with the end cap rather than being formed with a cone portion. 
     According to the invention, a method of manufacturing a dental apparatus is contemplated which includes the steps of: providing an elongated hollow tubular metal stock, providing a glass bead finish on a handle portion of the hollow tubular metal stock, scoring the handle portion first with a first helical grip enhancing pattern, then scoring with a second, displaced helical grip enhancing pattern, and separating the handle portion from the elongated stock by cutting, forming an individual handle. 
     The first pattern can be scored with a metal cutting tool having a pointed end for providing a scoring with a substantially narrow, V-shaped cross section. The second pattern can be scored with a cutting tool having a flat end, to produce a scoring with a substantially wide, rectangular cross section. Preferably, the first and second patterns are each crisscrossed double helical patterns, formed by axially rotating and passing the tubular stock in forward and reverse direction, along the axis of the tubular stock, against the stationary cutting tools. 
     After the stock has been cut into individual handles, the closing members can then be assembled into the cut open ends of each of the handles and held there temporarily by a sufficient friction fit or press fit, and then brazed in place. A brazing compound is pre-applied to an inside surface of the handles at ends thereof. The handles are heated to melt the brazing portion to fuse the closing members to each of the handles at the opposite ends thereof. 
     The present invention provides an effective and cost efficient method of securing implements or tool parts to instrument handles. The closing members can be brazed firmly to the handle providing a reliable and smooth appearing connection thereto. The invention provides a sure gripping surface treatment of the handle portion which increases the ability of the user to make precise manipulations and movements with the instrument. 
     The invention provides a method of manufacturing a dental apparatus which results in cost effective manufacturing and a reliable article manufactured thereby. 
     Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of a dental apparatus according to the present invention; 
     FIG. 2 is a fragmentary perspective view of a first stage of manufacturing of the apparatus shown in FIG. 1; 
     FIG. 3 is a fragmentary perspective view of a second stage of manufacturing of the apparatus of FIG. 1; 
     FIG. 4 is a fragmentary perspective view of a third stage of manufacturing of the apparatus of FIG. 1; 
     FIG. 5 is an exploded perspective view of a fourth stage of manufacturing of the apparatus of FIG. 1; 
     FIG. 6 is an enlarged fragmentary sectional view of a portion of the apparatus of FIG. 1; 
     FIG. 7 is a sectional view of a fifth stage of manufacturing of the apparatus of FIG. 1; 
     FIG. 8 is an enlarged fragmentary perspective view of a portion of the apparatus of FIG. 1; and 
     FIG. 9 is an enlarged elevational view of the handle shown in FIG. 4. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     While this invention is susceptible of embodiment in many different forms, there are shown in the drawings and will be described herein in detail specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated. 
     FIG. 1 illustrates a dental apparatus or instrument 10 which includes a handle 14, and two closing members 16, 18 which each partially interfit into one open end 19, 20 of the handle 14. Tool parts or implements 22, 24 are then fixed into the closing members 16, 18 respectively. The handle 14 includes a substantially smooth center section 25 bounded by surface contoured sections 26, 27. Although both the closing members 16, 18 are shown as carrying tool parts, one of the closing members can alternatively include an end cap for merely closing an open end of the handle. 
     FIGS. 2 through 7 illustrate manufacturing steps of the dental apparatus. FIG. 2 illustrates the first manufacturing step. An elongate tubular stock 30, typically 12 feet long, and composed of 304 stainless steel, is rotated in a direction R about its axis A and treated by a grinding roll 34, and by a spray nozzle 36 spraying or &#34;blasting&#34; silicon carbide particles. The stock is ground from 0.375&#34; diameter to 0.371&#34; diameter. The silicon carbide used for blasting can be a combination of 60 and 80 grit. The combined action of the grinding roll 34 and the spray nozzle 36 produce a &#34;glass bead&#34; finish on the handle outer surface 37. The tubular stock 30 is then axially advanced in an axial direction A relative to the grinding roll 34 and the spray nozzle 36. 
     FIG. 3 shows the finished surface 37 being further processed downstream of the position shown in FIG. 2, by a flat scoring tool 38 and a pointed scoring tool 42. The stock 30 is axially rotated in the direction R and axially moved in the direction A. The pointed scoring tool 42, being upstream of the flat scoring tool 38 in the direction of advancement A of the stock 30, is engaged to the stock 30 and applies the V-shaped grooves 44 initially within any to-be-contoured surface region 26, 27 during which time the flat scoring tool 38 is disengaged from the stock 30. Next, in sequence, the pointed scoring tool 42 is disengaged from the stock 30, the stock is indexed in the direction A, and the flat scoring tool 38 is engaged to the stock 30. 
     The flat scoring tool 38 applies the flat wide grooves 40 superimposed over the previously scored region having the previously applied V-shaped grooves 44, to sequentially complete the contouring of each of the regions 26, 27. The scoring tools or cutters 38, 42 are retracted or extended along the radial directions 48, 49 to engage and disengage the stock 30 during the cutting sequences. 
     The stock 30 is moved along the direction A in forward and reverse directions, during cutting of the V-shaped grooves 44 and during cutting of the wide grooves 40 in order to crisscross the grooves 40, 42, respectively. The stock 30 is moved more slowly in the axial direction A (or the stock rotated more rapidly) during scoring of the V-shaped grooves 44, to cut three times as many grooves 44 as the scoring tool 38 cuts wide grooves 40. 
     The scoring tool 38 eradicates every third one of the V-shaped grooves 44 when superimposing the wide grooves 40 on the regions 26, 27. The scoring tools 38, 42 may make several passes in reverse directions across each region 26, 27 to make grooves 40, 44 of the desired depth. The grooves are preferably cut 0.004 to 0.006 inches deep. The wide grooves 40 can be about 0.041 inches wide. The narrow grooves 44 can be about 0.015 inches wide at the surface and about 0.013 inches wide at the groove bottom. The scoring tools thus provide two displaced double helical scoring patterns, one comprised of narrow grooves and one comprised of wide grooves. At the end of each region 26, 27 a non-helical axially oriented band 41, 42 respectively is cut, continuous with the wide grooves 40. 
     After the regions 26, 27 have been scored with both style grooves 40, 44 the stock 30 indexes a distance approximately equal to the length of one handle 14, to begin scoring on two new spaced apart regions 26, 27 with the scoring tools 38, 40. As illustrated in FIG. 3 the scoring between the adjacent regions 26, 27 is spaced by a gap 51. The stock 30 retains the glass bead surface in this gap 51. 
     FIG. 4 illustrates a handle cutting step using a rotary cutter 50 movable in the radial direction 54 to separate finished handles 14 from the stock 30. The cutter is located downstream of the scoring tools 38, 42 shown in FIG. 3. The stock 30 is cut at a midpoint of the gap 51, leaving bands 51a, 51b on the adjacent regions 26, 27. After the handles are separated, a brazing compound or paste 68 is applied into each open end 19, 20 of each handle. 
     FIG. 5 illustrates the next step in the manufacturing process wherein the closing members 16, 18 are press fit into open ends 19, 20 of the handle 14, respectively. The closing members 16,18 have attachment portions 64 which have base diameters sized to be substantially press fit or frictionally fit into the open ends 19, 20 as described below with regard to FIG. 6. 
     As shown in FIG. 6, the closing member 16, typical of both closing members 16, 18 includes a tool-receiving body portion 60. The tool-receiving body portion 60 is substantially frustoconical in shape and has a tool-receiving port 61 for receiving a shank end 62 of a tool 22 (as shown in FIG. 8). The body portion 60 can have a band 60a of surface contouring, such as knurling, for improved gripping on the body portion, as shown in FIG. 5. 
     Alternatively, for a single tool instrument, one of the closing members 16, 18 can have an end cap (not shown) instead of a tool-receiving body portion, for merely closing one open end 19, 20 of the handle. 
     The closing member 16 includes the attachment portion 64 depending from the tool-receiving body portion 60. Attachment portion 64 interfits into the open end 19 until a shoulder 69 abuts an end surface 70 of the handle 14. The attachment portion 64 includes an undercut end region 66 adjacent a somewhat thicker base region 67. The base region 67 has an outside diameter slightly larger than an inside diameter of the open end 19 to facilitate a press fit between the attachment portion 64 and the handle 14. The brazing compound 68 is pre-applied to an inside of the handle at the open ends 19, 20. When melted by heating, the compound 68 flows by capillary action into the undercut region 66 and when cooled, the brazing compound 68 joins the closing members 16, 18 to the handle 14. 
     As shown in FIG. 7, a heat supply indicated schematically as &#34;H&#34; is then applied to the handle and attachment portions to melt the brazing compound 68 and firmly join the closing members 16, 18 to the handle 14. The heat supply is advantageously provided by a vacuum oven to prevent discoloration of the instrument 10. The heat supply can also be provided by another suitable heat source. 
     As illustrated in FIG. 8, a tool part 22 is then press fit into the tool-receiving port 61 of the closing member 16. The tool part 24 is fit in substantially identical fashion to the closing member 18. The tool shank 62 is frictionally held within the tool-receiving body portion 60. An adhesive can be used between the tool-receiving aperture 61 and the tool shank 62 to additionally secure the tool part. The adhesive can be cured in the vacuum oven during the brazing operation. 
     As illustrated in FIGS. 8 and 9, the narrow grooves 44 intersect each other at first positions 44a. The wide grooves intersect each other at second positions 40a. In the finished product, across a reference line 80 shown in FIG. 9, there are two first positions 44a between each adjacent second positions 40a. In the finished product there are approximately twice the amount of narrow grooves 44 as wide grooves 40, as illustrated in FIG. 9. 
     As shown in FIG. 9, the application of crisscrossed wide grooves 40 and narrow grooves 44 creates a pattern of raised small triangles 90 which are themselves grouped into triangle group patterns 92. The patterns 92 provide a sure grip and feed for the user manipulating the handle 14 to work the tool parts 22, 24 with precision, in a non-slip secure manner. 
     From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.