Winding and tightening tool and method for manufacturing same

[57] ABSTRACT

An angle drive manually-operated tool as for winding and tightening around a tooth, a matrix band preformed into a loop and having one end wound into a cylindrical coil having a central socket, the tool having a winding member engageable to said socket. Said tool comprising, in combination, a palm grip rotatably mounted on one end of an elongated rotatable driving member and on its other end a replaceably mounted flexible drive sleeve unit with a pre-angled guide shaft internally and pivotably suspended therein, thereby providing said rotatably angle drive tool with having on its terminal end a rotatable winding member, which automatically pivots and aligns with the axis of said matrix coil socket, said tool includes an internal torque-limiting means in said driving member.

Claims, 21 Drawing Figures

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PATENTED OEC 10 1974

3,852,884

SHEET 1 OF 2

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PATENTED DEC 10 1974

3,852,884

SHEET 2 OF 2

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FIG. 19 FIG. 20 FIG. 21

3,852,884 thereby destructively pivoted, relative to the central socket of the spirally wound end of the matrix band, and thus, render said matrix coil twisted and damaged’

WINDING AND TIGHTENING TOOL AND METHOD FOR MANUFACTURING SAME

CROSS-REFERENCE TO RELATED APPLICATION

The present invention pertains to a winding and tightening tool particularly adapted, such as for use with a pre-formed dental matrix band which is looped and has one end wound into a coil having a central socket which receives for tightening a racheted winding member on the tool of the present invention, said preformed dental matrix band being the subject of applicant’s prior matrix U.S. Pat., No. 3,411,214, issued Nov. 19, 1968, and co-pending U.S. matrix Pat. application, Ser. No. 382,833, filed July 26, 1973.

BACKGROUND OF THE INVENTION

The present invention primarily comprises an improvement over the prior tool comprising the subject matter of applicant’s prior U.S. Pat., No. 3,435,905, issued Apr. 1, 1969. Said prior tool was effective to accomplish the basic functions capable of being performed by the tool comprising the present invention; however, said prior tool lacked certain desirable features which have come to the attention of the applicant in the interim since the issuance of said prior patent for purposes of facilitating the use of said tool by a dentist, especially for purposes of preventing any serious damage to said tool, or to the matrix band or the destruction thereof prior to the same being completely mounted in operative position around a tooth. Especially, when used by so-called heavy-handed dentists, particularly those who are accustomed to using conventional matrix bands and tightening tools. Such conventional matrices and tools require substantial force to complete the tightening of said conventional matrix band into desired, final position around a tooth. Likewise, said prior tool was capable of transmitting undesirable twisting forces and thereby causing damage to applicant’s matrix band which is primarily designed to be used with said prior tool. The work habit of said heavy-handed practitioner could cause destructive wrist twisting action during use of prior tool.

In said prior tool, one of the principal causes of the transmission of destructive twisting to the matrix coil is the rigid mounting of the palm grip on one end of an elongated internal bearing member and bent guide shaft and is fixed thereto, whereby when said palm grip is held in the palm of the operator and the driving member is rotated, as is intended, any wrist rotation by the operator causes undesirable twisting of the guide shaft during use of the tool, which causes the axial alignment of said winding member, rotated at the terminal end of the flexible driving sleeve unit, to be disturbed with relation to the axis of the central socket in the spirally wound end of the matrix band, thereby sometimes causing destructive damage to the matrix band, incident to.the matrix being tightened about the tooth.

Further, in said prior tool an internal malleable guide shaft which is subsequently bent, after assembly, is fixedly connected to the end of the bearing member on the opposite end to which the palm grip is fixed, whereby should said palm grip thereon be undesirably pivoted, incident to an undesirable twist of the wrist during use of the tool, the axial alignment of the winding member which is rotatably carried by the outer end of said rigidly connected bent guide shaft also is

Still another need for improvement of said prior tool lies in the fact that a chuck which is rotatably supported adjacent the outer end of the aforementioned bent guide shaft and is rotatably carried by and fixed to the outer end of a flexible drive sleeve rotatable around 10 said bent guide shaft, the terminal end of the guide shaft being disposed within the wires of the flexible member to which the chuck is connected, whereby there is a tendency for the flexible sleeve, which is comprised of coengaged flexible coiled wires to become de15 structively abraised and damaged by rotatable engagement with the terminal end of said rigidly supported, bent guide shaft.

Still other important improvements also Were needed over said prior tool and the same are obviated by the 20 tool comprising the present invention, the objectives of which are as follows:

SUMMARY OF THE INVENTION

It is the principal overriding objective of the inven²⁵ tion to provide an improved winding tool, such as for use for tightening of applicant’s matrix band around a tooth in which the ratcheted winding member substantially automatically disposes itself in axial alignment within the socket of the coiled end of the matrix band ³⁰ for the winding thereof without thereby impairing the winding capabilities of the tool or the matrix for purposes of tightening said matrix coil, and thereby, tightening the band around a tooth. Ancillary to the forego_ ing object, it is a further object to provide a floating arrangement for an improved pre-angled shaft which is pivotably suspended within the flexible drive sleeve unit, said improved, pre-angled shaft having opposite angularly related end portions protruding from a segment of flexible sleeve and supported thereby and ^υ pivotable therein, at the opposite ends of said flexible member by a dual socketed collar at one end and an improved socketed chuck, supporting the other end of said shaft with a winding member at the outer end of ₄₅ the tool opposite the end which is rotatably supported in the palm of an operator.

Still another object of the invention is to provide a floating palm grip or handle member, which normally is disposed in the palm of the operator and from which ₅₀ a rod-like, finger-rotated driving member extends, the rotatable connection between said driving member and palm grip member permitting free rotation of the driving member with respect to the palm grip member and vice versa, whereby twisting of the wrist of the opera55 tor will not affect the axial alignment of the winding member of the tool with respect to the socket of the coiled end of the matrix band.

In connection with said destructive twisting forces, a further improvement of this invention is to provide a 60 g^u.’d^e shaft that is not rigidly connected to the palm grip or any other of said improved mechanisms, except being pivotably suspended within the flexible drive sleeve as will be further described.

An objective of this invention is to provide an im₆₅ proved pre-angled guide shaft whose one terminal end extends beyond said flexible sleeve and terminates in a protective socketed encasement in said chuck whereby the destructive forces of the terminal end of the guide

3,852,884 shaft are isolated so that previous damage to flexible sleeve wires is eliminated as will be described.

A further objective is to provide a pre-angled guide shaft to eliminate the bending procedure of said shaft, after assembly, which in prior tool, often caused destructive kinks in said flexible sleeve wires due to having been bent after final assembly of said tool by the operator; said improved guide shaft is bent prior to assembly.

Still further, to provide a dual collar and chuck encasements for the assembly and suspension of said preangled shaft within said sealed flexible drive sleeve unit which is thereby a readily replaceable unit, with an improved chuck and winding member at the terminal end of said flexible sleeve unit which provides a socket for said suspended, pivotable, guide shaft and flexible sleeve unit.

An improved shaft for the winding member which provides for a shoulder on said winding member shaft to limit the depth of the entry of said shaft into said 20 chuck enclosure, which thereby establishes internal dimensions to receive the suspended guide shaft, in said chuck socket, including clearances therein, for rotation on said shaft.

One further object of the invention is to provide the aforementioned pre-angled shaft and flexible sleeve thereon in the form of a demountable, replaceable, flexible drive sleeve unit, readily removable from a socket in the end of the driving member which receives One end of said flexible unit, whereby if damage of any kind occurs to said unit, as from continued use, it readily may be replaced by a substitute unit.

Still another object of the invention is to provide automatically releasable clutch means between the driving member and said flexible drive sleeve unit, whereby when the coil of the matrix band has been tightened to a predetermined extent established by the capability of the clutch means, any further attempt to tighten the coil of the matrix band will be prevented due to said clutch means permitting disengagement between the ⁴⁰driving member of the tool and a rotatable barrel clutch member. Re-engagement of said clutch is incident to further use of the tool· as will be described hereinafter.

Details of the foregoing objects and of the invention, as well as other objects thereof, are set forth in the following specification and illustrated in the accompanying drawings comprising a part thereof:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the winding tool embodying the principles of the present invention.

FIG. 2 is a fragmentary, foreshortened, partially vertically sectioned view of the tool shown in FIG. 1 and illustrating the rotatable palm grip assembly and flexible sleeve assembled to the driving member. Arrows indicate normal rotary movement of components during use of tool.

FIG. 3 is a vertical sectional view, illustrated on a larger scale than in the preceding figures, showing details of a replaceable unit at the forward end of the tool comprising a pre-angled shaft, rotatably mounted by a flexible driving sleeve member with said shaft being suspended between a socketed chuck at the outer end of the unit and an insertible elongated socketed collar member disposable within a socket at one end of the driving member of the tool.

FIG. 4 is a fragmentary, vertically sectioned view of the outer end of the tool of the prior art as similarly shown in FIG. 3 of present invention for purposes of comparing details of the prior art to the present invention.

FIG. 5 is an exemplary perspective view showing the prior art means for forming flexible sleeves employed in the unit shown in FIG. 3.

FIG. 6 is an exploded perspective view of one section of the flexible sleeve arrangement shown in FIG. 5 to illustrate details of one section thereof in accordance with prior art structure and showing an improved small collar.

FIG. 7 is an exemplary vertical sectional view taken through the flexible sleeve means shown in FIGS. 5 and 6, and also additionally illustrating details of the prior art being utilized in present invention.

FIG. 8 is a fragmentary view illustrating prior art means for forming the flexible sleeve illustrated in FIGS. 5-7.

FIG. 9 is a side elevation showing a typical manner of employing the pre-angled winding tool comprising the present invention and showing the same mounted in winding relationship with a coiled end of a matrix band surrounding an exemplary tooth, said view also showing directional arrows illustrating motions employed in operating the tool, both in regard to the prior art and the present invention.

FIG. 10 is a side elevation of the prior art winding tool, said view being principally in vertical section to show details thereof.

FIG. 11 is a side elevation of a pre-angled shaft upon which the flexible sleeve of the winding mechanism is adapted to be mounted.

FIG. 12 is a perspective view of the one-piece unit of the prior tool comprised of a palm grip, an internal bearing rod and guide shaft of the winding tool of the prior art, illustrating the pivoting of the tip of the bent guide shaft at the outer end of the guide, and the pivoting of said palm grip as indicated by arrows.

FIGS. 13 and 14 respectively are illustrations of a prior art winding tool shown in engagement with the coiled end of a matrix band in FIG. 13, and in FIG. 14, showing the manner in which the prior art tool causes a positive, pivoting malfunction of the winding member when palm grip is rotated as in FIG. 12, and illustrating m FIG. 14, the destructive pivoting to the coiled end of the matrix band.

FIG. 15 is a view similar to FIG. 13, but illustrating the improved winding tool of the present invention to show how destruction, such as illustrated in FIG. 14, will not occur with said improved tool, even with similar palm grip rotation, as indicated by similar arrows on palm grips in FIGS. 14 and 15.

FIG. 16 is a perspective view of the winding tool of the present invention illustrating some of the details of the releasable clutch means for the driving unit, and also, in vertical section, showing details of the rotatable mounting of a hand-held palm grip at the outer end of the modified rotatable driving member.

FIG. 17 is a fragmentary vertical sectional view, showing some details of the mounting for the replaceable, flexible drive sleeve unit in one end of the socketed, rotatable, modified driving member and also showing details of the releasable ball/socket clutch between the modified driving member and the flexible driving sleeve unit normally driven thereby.

3,852,884

FIG. 18 is a fragmentary perspective view of one end of the elongated barrel with view of the ball/spring channel seen therein as shown in FIG. 17 for reception of the barrel within the socket at one end of the modified rotatable driving member.

FIGS. 19-21 are enlarged vertical sectional views as seen on the line A—A of FIG. 17 and respectively showing various positions of the clutching members of the releasable clutch means by which the modified rotatable driving member actuates the chuck supported at the outer end of the replaceable flexible drive sleeve unit, the individual figures respectively showing an initial view of the clutching elements in engaged position, disengaged position, and lastly, in re-engaged position.

DETAILED DESCRIPTION

Referring generally to the drawings, this winding tool embodies improvements over applicant’s prior U.S. Pat. No. 3,435,905, issued Apr. 1, 1969. Reference will now be made as to the function of the improved winding tool invention as provided in this application.

While significant improvements are represented in this application, several basic principles of applicant’s prior patent are retained, where applicable. Where the prior art is retained, it will be so referred to and the improvements will be distinguished thereover.

As in applicant’s prior tool patent, the function of this improved tool 10 of FIGS. 1, 9 and 15, is to act as a winding member, for example, when tightening the coil off the applicant’s dental matrix. As in use with the applicant’s matrix, this hand-operated tool 10 transmits a horizontal winding force and converts said force into a near vertical winding force when its angled tool tip, winding member 14, is inserted into the coil 76 of the matrix 74 for winding and tightening the same. As in FIGS. 9 and 15, the rotation of the driving member 20, in turn, winds a flexible drive sleeve 48, which winds the bur-like winding member 14 of chuck 16, when it is inserted into the coil 76 of matrix 74, the ratcheted teeth 15 of winding member 14 automatically engages the I.D. of the coil 76 and winds and tightens said matrix coil 76 when tool 10 is operated, as in FIGS. 9 and 15.

The principal objective is to continue the rotation of ⁴⁵coil 76 by tool 10 until the matrix 74 is tightened about the tooth 72. Improved tool 10 of the present invention is operated by rotating the driving member 20 with the forefingers while holding the rotatable palm grip 30 in the palm of the same hand, as seen in FIG. 9. Arrows shown in FIG. 9 illustrate normal tool and wrist rotation. Rotation of driving member 20 transmits the rotatable driving force into the improved flexible drive sleeve wires 48, which, in turn, transmits said force into the ratcheted winding member 14 which winds and locks the matrix coil 76. To remove the tool 10 from its engagement in said coil 76, the winding tool member 20 is wound reversely to the coiling direction. The winding member 14, as in prior tool, is unidirectional, and thereby is disengaged from the inner windings of the coil when rotated reversely, while simultaneously withdrawing said disengaged winding member 14 axially from the coil 76. In prior tool, when tool ‘A’ of FIG. 10 is used in dental matrix work, any undue wrist twisting or torque to palm grip T, could cause destruction of the matrix 74 by twisting the coil 76 of the maxtrix 74 and additionally bring about excessive and uncomfortable force against the tooth 76. It is desirable, therefore, to automatically control the amount of twisting force that can be applied by said heavy-handed practitioner.

As shown in FIG. 9, the wrist 77 of the practitioner could be undesirably employed to create said undesirable twisting in the use of a winding tool A, as shown in FIGS. 13 and 14. Such twisting is employed in use of other tools and with other conventional matrices which 10 necessarily require greater amounts Of torque to effect the desired fit of the matrix to the tooth, and thereby resulting in discomfort to a patient.

In contrast to the foregoing, when using the improved tool 10 of FIGS. 9 and 15, no excessive torque is re15 quired to acquire a tight fit of applicant’s matrix 74 on the tooth 72. This results in greater comfort to the patient and no damage to the matrix or tool. Therefore, to avoid such unrequired torque and tool twisting, several improvements were added to the prior art tool, ²⁰ among these being the improved palm piece 30 which was made free-floating, so that, unlike the prior art, when the driving member 20 is rotated by the fingertips of the practitioner, as in FIG. 9, the wrist 77 rotation indicated by the dashed arrow, will in no way cause any ²⁵ destructive twisting of the matrix coil 76. This is because the improved palm piece 30 is rotatably engaged to said tool 10 and is not fixed to any of the winding mechanisms, nor is it connected with the pre-angled internal shaft 46 which is pivotably suspended within ³⁰ socket 67 of the flexible sleeve assembly 12. In prior tool, the guide shaft K was rigidly fixed to the palm grip T, as in FIGS. 10, 12,13 and 14. Inasmuch as improved palm grip 30 is disconnected and rotates freely, any twisting of the palm grip 30 will not be transmitted through the flexible sleeve assembly unit 12, nor into the ratcheted winding member 14 and matrix coil 76. The function of this improved rotating palm piece 30 is to serve as a good holding means, to direct the pitch of tool 10 and yet prevent any rotation of the wrist in any way from destructively affecting the operation of the tool 10 or the matrix 74. The pivotable disposition of the suspended, pre-angled shaft 46 in socket 67 comprises another improvement, and will hereinafter be described.

In applicant’s prior tool, the palm grip ‘T’ was rigidly attached to the inner bearing Q, and the malleable guide shaft K and G, as clearly seen in FIG. 12. FIGS. 10, 12, 13 and 14, illustrate the prior art and show how ₅₀ any amount of rotation or twisting of the palm piece T by the wrist causes a pivoting of the end of the bent shaft G of the shaft K to G', as shown by dashed lines, as seen in FIG. 12.

Said pivoting of shaft K at tip G results in a destruc55 ^dve action of the matrix 74 into which it was inserted, as in FIGS. 13-14, and Will later be described. The freely rotatable palm piece 30 and the improved, pivotable, pre-angled shaft 46, as seen in FIGS. 1-3 and 11, combine to overcome the potential destructiveness of ₆₀ the undue wrist action as shown in FIGS. 12,13 and 14 of the prior art, to be later described herein.

Briefly, the novel tool of the invention shown in FIGS. 1-3 includes in combination a handle assembly 10 and a driving member 20 which has at one of its ends said rotatable palm grip 30, mounted thereon and at the tapered end 22 of the member 20, a flexible sleeve assembly unit 12, which is replaceably secured to said rotatable driving member 20 which, in turn, ro3,852,884 tates at the extreme end of tool 10, a chuck 16 which is arranged to interchangeably receive tools such as the conical ratcheted winding member 14, for engagement with applicant’s matrix coil 76, as seen in FIG. 9.

FIGS. 1 and 2 illustrate the handle assembly 10 and include the improved freely rotatable disk-like palm grip 30. Said rotatable palm grip 30 may be of a suitable metal, such as Monel metal or aluminum, or plastics, and is arranged to be easily gripped in the palm of one using this tool 10. Said improved palm grip 30 has 10 a deep socket 36 extending into it from one edge. The improved driving member 20 has near one end, a circumferential annular groove 28 that is part of a journal 26, which fits into the deep socket 36 of the palm grip 30. With the journal 26 inserted into the palm grip 30, a spring pin 34, as seen in FIG. 2, is inserted into hole 32 which transverses socket 36 of the palm grip 30, shown in FIGS. 1 and 2. When fully inserted, the pin 34 traverses the channel 28, and in a free-spinning, rotatable engagement, holds the palm grip 30 on the journal 26 of the driving member 20.

When operating tool 10, the driving member 20 also is freely rotatable in the palm grip 30 with the fingers when said palm grip 30 is held in the palm of the user’s hand, as seen in FIG. 9. previously, in the prior art, as 25 in FIGS. 10 and 12, the palm grip T was rigidly connected to an inner bearing Q that ran through a hollow, tubular driving member P, with said malleable guide shaft K extending through the coreless flexible sleeve portion of tool A and terminating at end G, inside ³⁰chuck D, as seen in prior art, FIG. 10. In the present invention, the driving member 20 is a solid metal rod and is also freely rotatable, as shown by arrows in FIG. 3. The improved driving member 20 has a socket 21, for receiving the replaceably engaged flexible drive sleeve ³⁵unit 12.

The objective of said drive sleeve is to transmit a rotational force from one angle to another as in said tool 10. In tool 10, the pre-angled guide shaft suspended within flexible sleeve 48 redirects the forces from that of the plane of the driving member 20 to the obtuse angle of said angled guide shaft 46, as seen in FIGS. 3 and 9 for intraoral use of the tool 10 in a patient’s mouth, as when used with applicant’s matrix 74 when winding coil 76.

FIG. 3 shows the improved rotatable flexible drive sleeve assembly 12 as being comprised of the following members: A non-connected, pivotable, angled shaft 46 suspended within the central passage in the coreless flexible sleeve assembly 12 unit, which has socket enclosures affixed at each ending. At one end of assembly 12, a socketed chuck 16 is soldered to the end 54 of flexible sleeve wires 48 and to the chuck 16 is affixed the ratcheted winding member 14, with set screw 18. At the end 55 of assembly 12, opposite chuck 16, there is a deeply socketed collar 38 which is soldered to the end 55 of the flexible sleeve 48, thereby sealing, in socket 67 of collar 38, the pre-angled shaft 46, which is suspended internally within the thus obtuse-angled flexible drive sleeve assembly unit 12.

In FIG. 2, the deep socketed collar 38 of assembly 12 is fitted into hole 39 of driving member 20 and locked therein by set secrew 24 which bears against flat 42 of the deeply socketed collar 38. In FIG. 3, the pivotable, pre-angle shaft 46, with its chamfered ends 70 and 71’ is sufficiently long so that the chamfered end 70 lies fully within the shaft socket 68 of socketed chuck 16, while the opposite end 70 of angled shaft 46 extends and is suspended deeply in the socketed hole 67 of collar 38. Shaft 46, while being long enough to reach from socket 68 of the chuck 16 through the flexible sleeve 48, and into the deep socket 67 of collar 38, is still short enough so as to leave a shaft clearance space 44 to permit unrestricted pivoting and rotation of tool 10 at the deepest portion of the socket 67 of collar 38, as shown in FIG. 3.

As in applicant’s prior tool patent, flexible sleeve 48 is composed of a pair of helical springs 82 and 84, which are coaxially telescoped and oppositely wound, and are formed over an aluminum mandrel 58, of suitable stainless steel or other suitably flexible material, such as, for example “Monel” metal, synthetic resins,’ etc. For clockwise rotation tool, as with tool 10, for said matrix, outer spring 82 is wound with a “left lay,” while inner spring 84 is wound with a “right lay,” as best seen in FIGS. 7 and 8, or vice versa, for tools with counterclockwise requirements.

In production of the assembly 12 unit, the inner ends of spring windings 82 and 84 are united by solder bands 55 and 54, as seen in FIGS. 5, 6, and as in prior art. The deep socketed chuck 16 in FIG. 3, then is soldered or brazed to end 54 of the flexible sleeve 48. The ratcheted winding member 14 then is fully inserted into the socketed chuck with the improved shoulder 64 of the winding member 14 against the tapered end of the chuck 16. A set screw 18 anchors the shaft 62 of the ratcheted winding member 14 inside socket 68 of chuck 16. Said shoulder 64 controls depth insertion of winding member 14 in socket 68 of chuck 16 of FIG 3.

To the opposite soldered band 52 of flexible sleeve 48, as seen in FIG. 3, an improved, short, smalldiametered collar 40 is soldered. Thereinafter preangled shaft 46 is inserted through the short collar 40. Said shortness of collar 40 permits axial passage of bend 66 of shaft 46 into the flexible sleeve assembly 12 until said end 70 of suspended, angled guide shaft 46 seats against the top of shaft 62 of winding member 14. The socketed extra long collar 38 is then telescoped over the projecting shaft 46 and the long collar 38 is soldered to the short collar 40 by means of solder fillet 100, as seen in FIG. 3. The affixed long collar 38 is then inserted into the deep hole 21 of the driving member 20, as seen in FIG. 2, and affixed therein with a set screw 24. Thus, when driving member 20 is rotated, the flexible sleeve assembly 12 unit is likewise rotated.

The flexible sleeve assembly 12 unit may be easily removed by loosening set screw 24, as seen in FIG. 2, which renders the flexible sleeve assembly 12, a disposable unit, in the event said windings 48 become fatigued from continued use. This disposable feature is one of the improved aspects of this invention. In the prior art, shown in FIG. 10, shaft K was bent after assembly of tool A, and due to the one-piece unit, comprised of the palm grip T bearing Q and shaft K of the ₆₀ prior art, it was necessary to tear down the entire tool A in order to replace a worn flexible sleeve L. Thus, if the winding became damaged in use, an entire new tool A was needed.

The flexible sleeves per se are produced as in the ₆₅ prior art, and this method of making the flexible sleeve is best illustrated in FIGS. 5, 6 and 8. Preferably, a plurality of flexible sleeves is formed simultaneously. This is done by forming two continuous lengths of helically

3,852,884 and oppositely wound spring sires 82 and 84 over an aluminum mandrel 58, as seen in FIGS. 5, 6 and 8.

In the prior art, as seen in FIG. 5, the continuous lengths of stainless steel wire are soldered at 54 and 55, and then are severed at lines 56, whereafter the nonsoldered aluminum mandel 58 is free to be removed from the resultant series of coreless flexible sleeves 48 as seen in FIG. 6. In the present invention, solder bands 54 and 55 are then smoothed and an improved short collar 40 is slipped thereover and bonded to the band 55 as by soldering or brazing. Similarly, chuck 16 is slipped over the solder band 54, Which has likewise been smoothed and chuck 16 soldered or brazed to the solder band 54.

The improvement to the flexible sleeve assembly 12 of FIG. 3 lies primarily in seven areas, namely, shoulder 64 of winding member 14, the socket 68 of chuck 16, the short, collar 40, the deeply socketed collar 38, the pre-angled shaft, the suspended, pivotable shaft 46, the advantages of which are hereinafter described, including the flexible drive sleeve, which in the present invention is a self-contained replaceable unit..

In applicant’s prior tool, shown in FIGS. 10 and 12, the shaft K or stem, as it was formerly named in applicant’s prior patent, was assembled into the flexible 25 sleeve, unbent. Previously, the shaft was bent at “U” (FIG. 12) after all soldering and joints were completed, the fully assembled, flexible drive sleeve L was gripped externally and then the semi-malleable shaft K was bent to a desired angle by bending the entire assembly L. ³⁰For two reasons, the post-assembly bending of shaft K proved undesirable. Firstly, the bending action of the semi-malleable shaft K often caused some destructive kinks in the windings of the flexible sleeve J and thus, on occasion, rendered the flexible sleeve unless prior to ³⁵fulfilling its usefulness.

Secondly, experience has proven that for stability a more rigid pre-angled shaft than previously used, was required in the application of the winding tool 10 for dentistry. The former semi-malleable shaft could too ⁴θ easily be accidently re-bent, during use, from its desired angle and so a more rigid pre-angled shaft is currently employed in the invention of the present improved shaft 46 of FIGS. 2 and 3. Additionally, in the prior art, only a single long, open-ended collar M, as seen in FIG. 10, was employed. The collar M needed to be long enough so as to be able to seat deeply enough into, the handle P in order to be engageable by the set screw N which needed to be located at a distance back from tapered end 22 to where wall thickness increases. Therefore, in the prior art, a rigid, one piece, pre-angled shaft would not have been able to pass through the hollow driving member P or the long collar M during the assembly operation of tool A. Thus, in the prior art, the bending had to be done after assembly as previously described, and this often caused said destructive kinking of the flexible sleeve L. This kinking is eliminated in the present invention by employing said improved, two-part collar system, namely, the short collar 40 and the long collar 38, which, in combination, permit the assembly of the pre-angled shaft 46.

In operation of the improved tool 10 of this invention, the flexible drive sleeve 12 rotates around the pivotable, preangled, suspended guide shaft 46. Thus, said pivoting, angled shaft 46 in the flexible drive sleeve assembly 12, combine to seek their own common axial alignment with the central socket of matrix coil 76. The sleeve unit 12 pivots on pre-angled shaft 46, whenever shaft 46 pivots in socket 67 of collar 38 as when in use in applicant’s dental matrix. This alignment is automatically maintained regardless of the angle of the coil 76 to the tool 10 or the rotary movement of the user’s wrist.

Further, pre-angling shaft 46 during manufacture, as described, also eliminates the need for a dentist to bei come involved in re-bending the shaft to the exact required angles that are needed for intraoral use. Said non-destructive bending is best produced under exacting, controlled conditions, where the tool is being manufactured.

This pre-bending of angle 66 of shaft 46 of FIGS. 3 and 11 being done previously to assembly as permitted with the use of collars 38 and 40 is an improvement over the prior art.

Also, as iii the prior art, FIG. 7 illustrates the relationship of the pre-angled shaft, 46 to the windings 82 and 84, and shows the space between the I.D. of the windings and the O.D. of shaft 46, except where bend 66 of pre-angled shaft 46 occurs. FIG. 3 shows the flexible sleeve 48 brushing against the preangled shaft 46 at the bend 66 in the flexible sleeve assembly 12. This frictional brushing prevents undesirable spring-back when flexible drive sleeve windings 48 are flexed during use in tool 10.

The improved socketed chuck 16 also adds longevity to the disposable assembly 12 unit by extending its usable life. In FIG. 4, the chuck D, with shafts K and G, represents the prior art, in which shaft K terminates at G, within the soldered wire section H of chuck D. During rotation of the flexible sleeve assembly L, the spring-like forces of the flexible sleeve L create pressure of the soldered wires H against the terminal ends of the shaft K in the direction of arrow Y. Continued pressures of X against G eventually become destructive by creating a loosening of the flexible sleeve wire strands X from within the soldered section H of chuck D. Eventually, such loosened strands X will wrap about the shaft end G and cause a jamming of the mechanism and prevent further rotation of the chuck D and the tool A and this will· cause failure of tool A. Therefore, the improved socket 68 of chuck 16 of the present invention is significant in preventing destruction of the terminal end of flexible wires 82 and 84 of sleeve 48, as will be described hereinafter.

Unlike prior tool A, in the present invention, as seen in FIG. 3, the shaft 46 terminates beyond the soldered wires segment 54 of the flexible.sleeve 48 with terminal end 70 of shaft 46 extending deeply into an improved shaft socket 68 where said terminal end 70 cannot contact or do damage to said soldered sleeve wires 54.

^{J J} Chuck 16 and socket 68 preferably are made of hardened steel and therefore, when normal pressures are exerted between end 70 of shaft 46, at exemplary point 60 inside chuck socket 68, shown in FIG. 3, the ₆₀ smooth, hard walls of inner shaft socket 68 support all said pressure, which results in no destruction to the flexible sleeve wires 82 and 84 in solderband 54, and no loose endings of the inner windings of the flexible sleeve 48 develop, thereby extending the life of the en₆₅ tire flexible drive sleeve assembly 12 unit of the present invention. To further extend the life of the tool, the ends 70 and 71 of preangled shaft 46 are chamfered so as to create the least amount of destructive friction and

3,852,884 . 12 wear between the socket 68 and the chamfered end 70 of the pre-angled shaft 46, and thereby also assure smooth rotation.

When using tool 10 with applicant’s matrix 74, the operator of tool 10 need do nothing in particular, to ef- 5 feet engagement except to insert the winding member 14 of the tool 10 into the coil 76, as shown in FIG. 9, and then rotate driving member 20 in order to effect a positive automatic engagement of the winding member 14, in the coil 76 that he desires to wind and tighten. 1( This engagement feature of the winding member was also a feature of applicant’s prior tool patent. However, the present invention offers improvements thereover which overcome certain operational difficulties experienced in the prior art under certain conditions herewith 15 referred to below. In the prior art, FIG. 13 shows tool A inserted and rotating in coil 76 of matrix band 74 which is about the tooth 72. Rotation of the winding member B is performed so as to rotate the coil 76 and thereby wind the matrix surplus around the coil 76 and 20 draw off all such surplus matrix until the matrix 74 fits tightly about the tooth 72. In FIG. 13 of the prior art, the palm grip T is shown level, as indicated by the directional arrow 108, which also indicates that the operator had not twisted his wrist. The palm grip T being 25 rigidly attached to the inner shaft K extends into the sleeve L and chuck assembly D which is also seen in FIGS. 10 and 12. In FIG. 13, matrix coil 76 remains vertical and undistorted during rotation.

However, in FIG. 14, the palm grip T of the same tool ³⁰A of the prior art, is being shown undesirably twisted as when used by said heavy-handed practitioner, with the palm grip T being pivoted and rotated as by the wrist of. the user as shown by directional arrow 109. Such rotation of angle 109 of the palm grip T, which is ³⁵directly connected to the internal shaft K and G as in the prior art, and is disposed within the flexible sleeve assembly L, causes the flexible drive sleeve assembly L to equally pivot destructively in the same direction in which the palm grip T is being rotated and thereby ⁴⁰causes the matrix coil 76 to be pushed away from the matrix 72 prior to fully tightening same and thus, causing destruction of the matrix band 74 prior to affecting the usefulness of it. However, in the present invention, in FIG. 15, although the freely rotatable palm grip 30 ⁴⁵is also pivoted, the improved assembly 12 of the tool 10 of the present invention does not pivot or twist and no destructive pivoting of the palm grip 30 is transmitted through to the winding member 14, and therefore, none occurs to the coil 76, which is successfully wound, ⁵⁰in spite of the similarity of directional angle 109 of the palm grip 30, in both FIG. 14 of the prior tool and FIG. 15 of the present tool. Therefore, the improved floating palm grip in FIG. 15 prevents any maleffect from pushing or pivoting the coil 76 while the driving member 20 ⁵⁵is being rotated. The stabilizing action of the present improved rotatable floating palm grip 30, in combination with the suspended guide shaft 46, maintains the winding member 14 in axial alignment with coil 76 of FIG. 15, in spite of strong angulation of the palm piece ⁶

As many practitioners can be expected to unnecessarily over-rotate the palm grip 30 due to the habit they acquired when using other matrices, other than applicant’s matrix 74, and just as the floating palm grip 30 ⁶⁵aids in preventing any destruction to either the tool or the matrix as a result of any rotary or twisting wrist action on the practitioner’s part, similarly, in FIG. 3, there is a floating nature to the suspended flexible drive sleeve assembly 12 unit, which completes the chain of protection as previously described.

FIGS. 16 through 21 illustrate a ball and socket force-limiting device 90, that prevents any undue finger-created torque from being undesirably transmitted to, and thereby preventing any destruction of the other mechanisms of the tool 10, such as the flexible sleeve wires 82 and 84 of FIGS. 3 through 9, from undue torque, or to the matrix band 74 which said tool 10 is winding. Said force-limiting device operates automatically whenever the practitioner employs any excess forces, such as he may be accustomed to applying with matrices of the past. Notably, the applicant’s matrix invention does not require such undue torque in order to effect adaptation of the matrix to the tooth, which provides increased patient comfort.

However, applicant’s matrix 74 can be excessively wound by said heavy-handed practitioner. The ball/socket releasable clutch of this improved invention prevents the transmission of such forces. This results in longer life for tool 10 and greater patient comfort.

FIG. 16 is a sectional view of the torque-limiting modified driving member 88. The freely rotatable palm grip 30 is the same palm grip as shown in FIGS. 1, 2, 9 and 15. The assembled flexible sleeve 12 unit is likewise the same as that shown in all previous figures pertaining to the present invention. The difference between tool 10 and tool 11 of FIGS. 16 through 21, is in the quad-socketed, dual ball and spring arrangement that comprises the torque-limiting device. The tool 11 has all of its modifications in two places. One is at the tapered end of the alternate ball-socketed, modified driving member 88. The other comprises the clutch member assembly of the ball and spring-retaining barrel clutch 90. These two features are seen in FIGS 16 and 17.

The ball spring-retaining barrel 90 is made of small enough diameter so as to be able to be rotatably fitted into socket 94 of driving member 88, with clearances, as shown in FIGS. 17, 19, 20 and 21. Said clearances permit unrestricted rotation of barrel 90 within said channel 92 in FIGS. 17-21. In FIG. 17, the balls 102 and spring 104 within the barrel 90 maintain the engagement of barrel 90 to driving member 88 by pressure of spring 106 forcing the balls into sockets 94 of said driving member 88. Barrel 90 is also fitted with a set screw 98 that is threaded through a suitable aperture in member 90 to anchor the collar 38 of said flexible drive sleeve assembly 12 unit securely within the barrel 90, as shown in FIG. 17. With this arrangement, when barrel 90 rotates, so then does flexible drive sleeve unit 12 rotate.

As shown in FIGS. 16 and 17, there are sockets comprising drilled holes 94a through 94d, of which there are 2 sets of pairs or four holes in the walls of socket 92 of modified driving member 88, as seen also in FIGS. 19, 20 and 21. FIGS. 16 and 17 also show the steel balls 102 projecting into and engaging the socket holes 94, in driving member 88, which are of a smaller diameter than the balls 102, and are held in engaged position with the sockets 94 by the force of the compression spring 104 between the pair of the steel balls 102, especially as shown in FIG. 17. FIG. 17 also sectionally shows the ball/socket arrangement in which the spring 104 and balls 102 ire disposed longitudinally in

3,852,884 a transverse bore 106 of barrel 90, which is shown in FIGS. 18, comprising an external view of FIG. 17.

Said clutch is assembled with the balls 102 and spring 104 being forcefully assembled into bore 106 of barrel 90. Then barrel 90 is forced into socket 94. Clutch disengagement occurs whenever balls 102 are dislodged from socket holes 94, which occurs only when excessive rotating force is being applied to modified driving member 88. Under such force, the balls 102 are depressed by the edges of sockets 94 and said clutch is then disengaged. However, continued rotation of tool 11 re-engages clutch.

The torque control setting of the tool is determined by the relative dimensions of two members, i.e., the spring-loaded balls 102, and the diameter of sockets 94. The smaller the diameter of the ball 102, the deeper said ball 102 becomes embedded in said socket hole 94, and therefore, a greater torque is required to dislodge the balls 102. Conversely, the larger the ball 102, or the smaller the socket holes 94, the less the ball becomes embedded in the socket which requires a lesser torque to release balls 102. Therefore, a greater rotational force of member 88 is required to dislodge a deeply embedded spring-loaded ball 102. Inasmuch as the flexible drive sleeve unit 12 of tool 10 shows fatigue at about 16 in. oz. of torque, and in dentistry, patient discomfort is obvious at 10 in. oz., and with about 12 in. oz. being destructive to applicant’s matrix 74, the desired torque-limiting device is thus best set at about 8 to 9 in. oz. By employing the correct combination of ball diameter to socket I.D. diameter, an 8 to 9 in. oz. torque is provided, while variations, in the combination of ball and socket diameters will provide any desired torque-limiting control means.

In actual practice, when the torque limiting tool 11 is employed, as in FIGS. 19, 20 and 21, the following occurs. The rotation of the modified driving member 88 would function exactly as driving member 20 in the tool 10, now shown in FIG. 15, with the exception that after initial rotation of tool 11 in coil 76, and the coil tightens against further rotation, then, when the resistance to continued rotation equals 9 in. oz. the torquelimiting mechanism of the tool 11 itself takes over the control of the amount of torque is permitted to be transmitted from the practitioner’s fingers to the rotating matrix coil 76 in the following manner. The matrix coil 76 requires about 6 inch-ounces of torque to tighten and lock the matrix 74 about the tooth 72, as in FIG. 15. The tool 11 would react in no new way if no more than 9 inch-ounces were applied to the modified driving member 88, as in FIG. 19. However, if the torque would exceed 9 inch-ounces of rotational force, said ball/socket clutch would disengage and as in FIG. 20, balls 102 would be depressed under and out of their engagement with sockets 94a and 94c, thereby causing a cessation of the amount of transmitted torque due to said disengagement. If the rotational torque is continued as in FIG. 21, then a re-engagement of the balls 102 into sockets 946 and 94rf is made again. Then, if ⁶⁰said excessive force is continued, the engagement, disengagement, and re-engagement would again occur as ball and sockets slip in and out, as shown in FIG. 20, thereby acting reliably as a force-limiting mechanism, as no force or torque is transmitted beyond 9 in. oz. to ⁶⁵either the winding member 14 or the matrix coil 76 whenever said disengagement occurs.

The arrows 78 in FIGS. 19-21 illustrate the direction of the rotation of the modified driving member 88, while arrow 80 illustrates the movement of the barrel 90. The reverse direction of the heads of arrows 80 in5 dicate where the barrel 90 has ceased to rotate due to the acquired tightness of the matrix 74 on the tooth which caused the disengagement of said clutch, as shown in FIG. 20, and thereby ceased to rotate said barrel 90.

Notably, when said matrix tightness is accomplished, said member 88 is still revolvable around said barrel 90 as long as 9 in. oz. of torque is still being applied, as indicated by arrows 78, repeatedly disengaging the balls 102 and sockets 94, and then re-engaging, etc., so long as rotation of modified driving member 88 is continued. During such occurrence, the practitioner becomes aware of the acitivity of the force-limiting mechanism by the sound of the clicking of the balls 102 into the sockets 94 and ceases further rotation of member 88 20 with an awareness that the matrix has been fully tightened, without undue torque forces having reached and the matrix or the tooth or having damaged the windings of the winding member 88 in any way. Said sonic clicking is another improvement in this invention.

²⁵ Any torque beyond the 9 inch-ounces would be destructive to the matrix 74, and any such continued excessive torque to the flexible sleeve assembly 12 could result in early fatiguing of the delicate flexible sleeve windings 82 and 84, and thereby reduce said wires’ usable life span. The torque-limiting device of this invention prolongs the life off the tool and also affords patient comfort by preventing said undue torque from reaching the patient’s tooth 72.

While the invention has been described and illustrated in its several preferred embodiments, it should be understood that the invention is not to be limited to the precise details herein illustrated and described since the same may be carried out in other ways falling within the scope of the invention as illustrated and described.