FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to clamping devices for clamping a member to a housing. The invention is particularly useful in dental handpieces for releasably clamping dental tools, and is therefore described below with respect to this application.
One form of dental handpiece to which the invention is especially suitable is the air turbine handpiece for driving a dental tool, such as a burr or drill, at extremely high speeds, e.g., in the order of 400,000 rpm. The clamping devices now commonly used in such dental handpieces are generally of a relatively bulky construction which increases the size and weight of the handpiece, do not securely hold the dental tool during the high-speed operation of the handpiece, and/or require relatively awkward forceful manual manipulations in order to remove and insert the dental tool with respect to the handpiece.
My prior U.S. Pat. Nos. 5,549,474 and 5,810,588 disclose clamping devices particularly useful for dental handpieces having advantages in one or more of the above respects. Other clamping devices are described, for example, in German Patent DE 2,50,3294, U.S. Pat. No. 5,254,004 and in U.S. Published Patent Application 2004014005.
OBJECTS AND BRIEF SUMMARY OF THE PRESENT INVENTION
An object of the present invention is provide a novel clamping device, and also a novel dental handpiece including such a clamping device, for manually clamping and releasing a dental tool or other member in a manner which is more convenient to operate, requires less force, and/or more securely holds the dental tool, as compared to the clamping devices and dental handpieces described in the above-cited patents and patent application.
According to one aspect of the present invention, there is provided a clamping device for clamping a member to a housing, comprising: a sleeve unit carried by the housing and having an open end formed with a tapered inner surface; a chuck unit receivable within the open end of the sleeve unit and having an open end which is radially contractible for receiving and clamping the member; the inner surface of the sleeve unit and the outer surface the chuck unit including interengaging threads such that the sleeve unit and chuck unit are both rotatably and axially displaceable relative to each other; a spring normally urging one unit in one rotary direction relative to the other unit such that the tapered inner surface of the sleeve unit is axially displaced relative to the chuck unit in one direction to engage and contract the open end of the chuck unit to a clamping position with respect to the member; and a manual operator effective, when operated, to produce a rotary displacement of the one unit in the opposite rotary direction relative to the other unit such as to displace the tapered inner surface of the sleeve unit axially in the opposite direction relative to the open end of the chuck unit and thereby to permit the open end of the chuck unit to expand to a releasing position with respect to the member.
Several embodiments of the invention are described below for purposes of example, when the manual operator is a push-button assembly which, in its normal position, permits the spring to urge the two units to the clamping position of the clutch unit, and which is depressible to rotate one of the units in the opposite direction to thereby permit the open end of the chuck unit to expand to a releasing position.
In several described embodiments, the push-button assembly is constructed, so as to be effective, when depressed, to rotate the sleeve unit, while rotation of the chuck unit is restrained, to thereby produce an axial displacement of the chuck unit relative to the sleeve unit in the direction permitting the open end of the chuck unit to expand to its releasing position.
In another described embodiment, the push-button assembly is constructed so as to be effective, when depressed, to rotate the chuck unit while rotation of the sleeve unit is restrained, to thereby produce an axial displacement of the chuck unit relative to the sleeve unit in the direction permitting the open end of the chuck unit to expand to its releasing position.
The invention also provides a novel dental handpiece having a clamping device constructed as set forth above for clamping a dental tool thereto. According to this aspect of the invention, there is provided a dental handpiece comprising a housing including a clamping device as described above wherein the chuck unit is constructed for releasably clamping a dental tool; the sleeve unit and chuck unit are both mounted on rotary bearings for rotation within the housing with the dental tool clamped therein, and the sleeve unit includes turbine blades for rotating the sleeve unit together with the chuck unit and the dental tool when clamped therein.
As will be more particularly described below, the foregoing features of the invention enable clamping devices, and particularly dental handpieces, to be constructed which permit very convenient attaching and releasing of the dental tool, which require relatively little force in order to attach or release the dental tool, and which securely hold the dental tool during the use of the device.
Further features and advantages of the invention will be apparent from the description below.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:
FIG. 1 is a side elevational view illustrating one form of dental handpiece constructed in accordance with a first embodiment of the present invention;
FIG. 2 is an enlarged, longitudinal sectional view illustrating the tool-holding section of the dental handpiece of FIG. 1;
FIG. 3 is a transverse sectional view along line III-III of FIG. 2;
FIG. 4 is a pictorial illustration of the sleeve unit in the dental handpiece of FIGS. 1-3;
FIG. 5 is a pictorial illustration of the chuck unit in the dental handpiece of FIGS. 1-3;
FIG. 6 is a pictorial illustration, generally from the front side, of the dental handpiece of FIGS. 1-3 with the housing and a part of the sleeve unit removed to better show the internal structure;
FIG. 7 is a pictorial illustration of the assembly illustrated in FIG. 6 but viewed generally from the rear;
FIG. 8 is a pictorial illustration of the push-button assembly in the dental handpiece of FIGS. 1-3;
FIG. 9 is a sectional view illustrating a modification in the construction of the chuck unit in the dental handpiece of FIG. 1;
FIG. 10 is a side elevational view illustrating another form of dental handpiece constructed in accordance with another embodiment of the present invention;
FIG. 11 is a longitudinal sectional view of the tool-holding section of the dental handpiece of FIG. 10;
FIG. 12 is a three-dimensional view illustrating the chuck unit in the tool-holding section illustrated in FIG. 11, together with the cooperating portion of the push-button operator;
FIG. 13 is a three-dimensional view illustrating the assembly of the chuck unit and sleeve unit in the tool-holding section illustrated in FIG. 11;
FIG. 14 is a three-dimensional view, similar to that of FIG. 13, but illustrating a further embodiment of clamping device constructed in accordance with the present invention; and
FIG. 15 is a three-dimensional view illustrating the chuck unit and a coupling member of the push-button assembly in the embodiment of FIG. 14.
It is to be understood that the foregoing drawings, and the description below, are provided primarily for purposes of facilitating understanding the conceptual aspects of the invention and possible embodiments thereof, including what is presently considered to be a preferred embodiment. In the interest of clarity and brevity, no attempt is made to provide more details than necessary to enable one skilled in the art, using routine skill and design, to understand and practice the described invention. It is to be further understood that the embodiments described are for purposes of example only, and that the invention is capable of being embodied in other forms and applications than described herein.
DESCRIPTION OF PREFERRED EMBODIMENTS
As indicated above, the clamping device of the present invention is particularly useful in dental handpieces for releasably clamping a dental tool in a manner which securely holds the dental tool, even during high-speed operation (e.g., 400,000 RPM) but which permits the dental tool to be conveniently removed and replaced by another one. The drawings therefore illustrate such dental handpieces constructed in accordance with several embodiments of the present invention.
The Embodiment of FIGS. 1-8
FIG. 1 illustrates a dental handpiece which includes a housing, generally designated 2, having a hand-gripping section 3 at one end, and a tool-holding section 4 at the opposite end for holding a dental tool 5, such as a burr or drill. Housing section 4 further includes a push-button assembly 6, which is depressible in order to release dental tool 5 and to permit attachment of another dental tool in a quick and convenient manner. Also included in housing section 4 is a water spray nozzle 7 which discharges a water spray onto the site being worked by the dental tool 5.
The illustrated dental handpiece, as to be described more particularly below, is a high-speed air turbine handpiece in which compressed air is supplied, via a conduit 8 at the back end of the handpiece, to an air turbine within housing section 4 to rotate the dental tool 5 at a very high speed, e.g., in the order of 400,000 rpm. The rear end of the dental handpiece includes a further conduit 9 for introducing water which is discharged in the form of a spray via nozzle 7 onto the working site of the dental tool.
As shown particularly in FIG. 2, housing section 4 houses: a sleeve unit, generally designated 10, having an open end formed with a tapered inner surface 11; and a chuck unit, generally designated 20, having an open end 21 formed with a tapered outer surface 21a and a plurality of axial slits 21b so as to be radially contractible for receiving and clamping the dental tool 5. Sleeve unit 10 is more particularly shown in FIG. 4, and chuck unit 20 is more particularly shown in FIG. 5. As will be described below, chuck unit 20 is movable axially with respect to sleeve unit 10 in a first direction to a clamping position wherein its slitted open end 21 is contracted by engagement with tapered inner surface 11 of the sleeve unit, or in the opposite direction to a releasing position wherein its slitted open end 21 is moved away from tapered inner surface 11 to permit open end 21 of the chuck unit to expand and thereby to release the dental tool 5. As will also be described below, the sleeve unit 10 and chuck unit 20 include interengaging elements such that rotation of one unit in one direction relative to the other unit, axially moves the chuck unit 10 to its clamping position; and rotation of one unit in the opposite direction relative to the other unit, axially moves the chuck unit to its releasing position.
The dental tool further includes a spring, generally designated 30, urging one unit in the one rotary direction relative to the other unit, to thereby move chuck unit 20 to its clamping position. Push-button assembly 6 serves as a manual operator effective, when manually actuated (depressed), to rotate one unit in the opposite rotary direction relative to the other unit, to thereby move chuck unit 20 to its releasing position. As described below, in the embodiment of FIGS. 1-8, the push-button assembly is effective to rotate the sleeve unit 10 and to restrain rotation of the chuck unit 20, such that the chuck unit 20 moves axially with respect to the sleeve unit to the releasing position of the chuck unit.
Sleeve unit 10, as best seen in FIG. 7, includes a front tubular section 12 and a rear tubular section 13. The front tubular section 12 is formed with the previously mentioned tapered inner surface 11 (FIG. 2), whereas the rear tubular section 13 is formed with axially-extending teeth 14 for a purpose to be described below. The two tubular sections 12, 13, are integrally formed with turbine blades, 15, 16, and are secured together by a plurality of fasteners 17. In addition, the inner surface of the front tubular section 12 is formed with internal threads 18 (FIG. 4) which serve as the previously-mentioned interengaging elements of the sleeve unit cooperating with complementary elements (threads) in the chuck unit 20, to move the chuck unit axially upon the rotation of the sleeve unit 10 relative to the chuck unit, to the clamping and releasing positions of the chuck unit.
As shown particularly in FIG. 6, spring 30 is a spiral leaf spring enclosing tubular section 12 of the sleeve unit 10 just forwardly of its blades 15, 16. The inner end 31a of spiral spring 30 is coupled to chuck unit 20, as will be described more particularly below, whereas the outer end 31b of the spiral spring is fixed within a recess 19 formed in one of the blades 15.
As best seen in FIG. 5, chuck unit 20 also includes a front tubular section 22 constituting the previously-mentioned open end 21 formed with the tapered surface 21a and the slits 21b, so as to be radially contractible by the tapered inner surface 11 of the sleeve unit 10 upon axial displacement of the chuck unit relative to the sleeve unit. Tubular section 22 of chuck unit 20 is further formed with external helical threads 23 rearwardly of the slits 21b and threadedly engaging internal threads 18 of sleeve unit 10 when the chuck unit is received within the sleeve unit.
As further seen in FIG. 5, chuck unit 20 includes a larger-diameter tubular section 24 rearwardly of the external thread 23, and a rear tubular section 25 of substantially the same diameter as the front tubular section 22. The larger-diameter section 24 of chuck unit 2 is formed with an axially-extending slot 26 for receiving the inner end 31a of spring 30. The outer end of the rear tubular section 25 of chuck unit 20 is formed with a plurality of axially-extending teeth 27 for a purpose to be described below.
As seen particularly in FIG. 2, chuck unit 20 is received within sleeve unit 10, and spiral spring 30 is received around the large-diameter section (24, FIG. 5) of chuck unit 20,with the inner end 31a of spiral spring 30 received within slot 26 of the chuck unit 20, and the outer end 31b of the spiral spring secured within recess 19 (FIG. 6) of the sleeve unit. Spring 30 thus couples sleeve unit 10 to chuck unit 20 to define a unitary assembly. This assembly is rotatably mounted within housing section 4 by a front ball-bearing 32 enclosing the front tubular section 12 of sleeve unit 10, and a rear ball-bearing 33 enclosing the rear tubular section 13 of the sleeve unit.
Housing section 4 further includes a front collar 35 receiving a vibration-absorbing O-ring 36 enclosing the front ball-bearing 32, and a rear collar 37 receiving a vibration-absorbing O-ring 38, enclosing the rear ball-bearing 33.
Push-button assembly 6 is located at the rear end of housing section 4. As shown particularly in FIGS. 2 and 8, the rear end of housing section 4 is closed by a threaded cap 40 formed with an annular space 41 for receiving push-button assembly 6, and with a large center opening 42 for accommodating elements of the push-button assembly when manually depressed, as will be described more particularly below.
As shown particularly in FIG. 8, push-button assembly 6 includes a push-button 60 carrying on its inner surface an outer hollow stem 61 and an inner hollow stem 62 telescopingly received within the outer hollow stem. Push-button 61 is urged outwardly by a coil spring 63 between the push-button and collar 37 (FIG. 2) of housing section 4; whereas the inner hollow stem 62 is urged outwardly of the push-button by a second coil spring 64 between the inner stem and the push-button. In the normal position of the inner stem 62, as shown in FIG. 8, it projects inwardly of the outer stem 61.
As also shown in FIG. 8, the inner end of the outer stem 61 is formed with an annular array of axially-extending teeth 65; and the inner end of the inner stem 62 is also formed with an annular array of axially-extending teeth 66. As will be described more particularly below, the initial depression of push-button 60, causes teeth 66 to engage teeth 27 (FIG. 7) of the chuck unit 20 to prevent rotation of the chuck unit; while further depression of push-button 60 causes teeth 65 to engage teeth 14 of the sleeve unit 10 to rotate the sleeve unit, relative to the chuck unit. During such rotation, the interengaging threads 18 of the sleeve unit 10, and 23 of the chuck unit 20, effect an axial displacement of the chuck unit with respect to the sleeve unit.
The manner of using the illustrated dental handpiece will be apparent from the above description. Thus, when a dental tool 5 is received within the chuck unit 20 as shown in FIG. 2, spiral leaf spring 30, having its opposite ends coupled to the chuck unit 20 and sleeve unit 10, respectively, applies a force to rotate the chuck unit with respect to the sleeve unit in the direction to cause the chuck unit to securely clamp the dental tool. That is, the interengaging threads 23 and 18 urge the chuck unit inwardly of the sleeve unit such that the outer slitted end 21 of the chuck unit is forced against the tapered inner surface 11 of the sleeve unit, and thereby is radially contracted to firmly hold the dental tool 5 within the chuck unit.
The dental handpiece may be used to perform the appropriate dental operation according to the dental tool 5 clamped thereto. High-speed rotation of the dental tool is effected by compressed air introduced via conduit 8 and applied to the turbine blades 15, 16 of the sleeve unit 10. During the rotation of sleeve unit 10 and the chuck unit 20, the dental tool 5 is securely clamped in the chuck unit by the rotary force applied to the sleeve unit by the spiral leaf spring 30. The direction of rotation of the dental tool is such as to increase the clamping force applied by the sleeve unit to the chuck unit.
Whenever it is desired to change the dental tool 5, push-button 60 is manually depressed to release the dental tool in the following manner: During the initial depression of push-button 60, teeth 66 on its inner stem 62 first engage teeth 27 (FIGS. 5 and 7) at the end of chuck unit 20 to hold the chuck unit against rotation. Further depression of push-button 60 causes teeth 65 on its outer stem 61 to engage teeth 14 at the end of sleeve unit 10 to manually produce a small rotation of the sleeve unit with respect to the chuck unit. This manually-produced rotation is effected against the action of the spiral leaf spring 30, and thereby stresses the spiral spring.
During this manual rotation of sleeve unit 10 relative to chuck unit 20, their interengaging threads 18 and 23 effect an axial displacement of the chuck unit 20 outwardly with respect to the sleeve unit 10, thereby moving the open end 21 of the chuck unit away from the tapered inner surface 11 of the sleeve unit. This movement of the chuck unit permits the open end 21 of the chuck unit to radially expand, thereby releasing the dental tool 5 and permitting another dental tool to be applied to the dental handpiece.
As soon as push-button 60 is released, the previously-stressed spiral spring 30 effects the rotation of the sleeve unit 10 relative to the chuck unit 20 in the opposite direction, thereby forcing the chuck unit back against the tapered inner surface 11 of the sleeve unit, to again firmly clamp the newly-introduced dental tool within the chuck unit.
It will thus be seen that, during the normal operation of the handpiece, the dental tool is securely held by the chuck unit 20, and that only a relatively light force is needed to be applied to push-button 60 in order to release the dental tool to permit its removal or replacement with another dental tool.
The Embodiment of FIG. 9
FIG. 9 illustrates a modification, wherein the spring between the sleeve unit 10 and the chuck unit 20 is a helical spring, shown at 130, rather than a spiral spring as shown at 30 in the above-described embodiment. One end 131a of spring 130 is coupled to the sleeve unit 110, whereas the opposite 131b is coupled to the chuck unit 120. FIG. 9 also shows the interengaging threads 118 of the sleeve unit 110, and threads 123 of the chuck unit 120, which effect the axial displacement of the chuck unit to its releasing and clamping positions during the manual rotation of the sleeve unit by the depression and release of the push-button (61, FIG. 8).
In all other respects, the construction and operation of the modification illustrated in FIG. 9 are generally the same as described above with respect to FIGS. 1-8, except that such a construction permits the sleeve and turbine to be constructed of a single part, rather than of two parts as in FIGS. 1-8.
The Embodiment of FIGS. 10-13
The dental handpiece illustrated in FIG. 10 is generally designated 200 and is similar to that illustrated in FIG. 1. It also includes a housing 202 having a hand-gripping section 203 at one end, and a tool-holding section 204 at the opposite end for holding a dental tool 205, such as a burr or drill. Housing section 204 further includes a manual operator in the form of a push-button assembly 206 which is manually depressable in order to release dental tool 205 and to permit attachment of another dental tool in a quick and convenient manner, and a water spray nozzle 207 which discharges a water spray onto the site being worked by the dental tool 205.
The dental handpiece of FIGS. 10-13 is also a high-speed air turbine handpiece in which compressed air is supplied, via a conduit 208 at the back end of the handpiece, to an air turbine within tool-holding section 204 to rotate the dental tool 205 at a very high speed, e.g., in the order of 400,000 rpm. The rear end of the dental handpiece includes a further conduit 209 for introducing water which is discharged in the form of a spray via nozzle 207 onto the working site of the dental tool.
As shown particularly in FIG. 11, the tool-holding section 204 of housing 202 also includes a sleeve unit 210 having an open end facing outwardly of the housing, and a chuck unit 220 received within the sleeve unit for clamping the tool 205 thereto.
As will be described more particularly below, in this embodiment the push-button assembly is effective, when depressed, to rotate the clutch unit, rather than the sleeve unit in the previously-described embodiments, to produce the required axial displacement of the chuck unit relative to the sleeve unit in the direction permitting the open end of the chuck unit to expand to its releasing position. In this embodiment, the push-button assembly includes a coupling member effective to accommodate the axial displacement of the chuck unit during its rotation by depression of the push-button assembly, such that the sleeve unit is neither rotated nor axially-displaced during the actuation of the clamping device to its releasing position.
As seen in FIG. 11, sleeve unit 210 includes a front tubular section 211 and a rear tubular section 212 secured together by a plurality of fasteners 213 (FIG. 13). The front tubular section 211 is formed with an inner tapered surface 214 cooperable, as will be described more particularly below, with a tapered surface 224 on chuck unit 220 to move the latter to its clamping or releasing positions with respect to the dental tool 205. The front tubular section 211 of sleeve unit 210 is further formed with internal threads 215 cooperable with external threads 225 on the chuck unit for moving the latter to its clamping and releasing positions, as will also be more particularly described below. The two tubular sections 211, 212 of sleeve unit 210 are formed with turbine blades 216, 217, secured together by the previously-mentioned fasteners 213, as best seen in FIG. 13. The rear tubular section 212 of sleeve unit 210 is further formed with a pair of diametrically-opposed axially-extending slots 218, one of which is seen in FIG. 13, for a purpose to be described below.
The construction of chuck unit 220 is best seen in FIG. 12. It also includes a front tubular section 221 and a rear tubular section 222 adapted to be received within the two sections 211 and 212, respectively, of sleeve unit 210. The juncture 223 of the two tubular sections 221, 222, is of a thickened diameter as shown in FIG. 12 and is received within a cylindrical channel formed by the two turbine blade sections 216, 217 of the sleeve unit 210, as shown in FIG. 11. The outer surface of juncture section 223 is formed with an axially-extending step 223a (FIG. 12) adapted to receive, by welding, the inner end 231a of a spiral leaf spring 230 (FIG. 11). The outer end 231b of spiral spring 230 is coupled to the section of sleeve unit 210 formed with the turbine blades 216, 217. Spiral spring 230 thus couples sleeve unit 210 to chuck unit 220 to rotate as a unitary assembly, and also to continuously bias the chuck unit to a clamping position with respect to the dental tool 205, as will be more particularly described below.
As indicated above and as further seen in FIG. 12, the open end of the front tubular section 221 of chuck unit 220 has a tapered outer surface 224 engageable with the tapered inner surface 214 of sleeve unit 210. The opposite end of the front tubular section 221 of chuck unit 220 is formed with external threads 225 interengaging with internal threads 215 of sleeve unit 210.
Front tubular section 221 of chuck unit 220 is also formed with a plurality of axially-extending slits 226 each extending from its front tapered edge 224 to an elongated opening 227. This construction is such that the open end of the front tubular section 221 is radially contractible and expandable by the engagement and disengagement of tapered surfaces 214 and 224 during the axial displacement of the chuck unit 220 with respect to the sleeve unit 210, as will be described more particularly below.
As indicated above, spiral leaf spring 230 couples sleeve unit 210 to chuck unit 220 so that both units rotate together, with the dental tool 205 clamped by the chuck unit, when the turbine blades 216, 217 are driven by compressed air supplied via conduits 208 (FIG. 10). For this purpose, the assembly, defined by units 210 and 220 coupled together by spiral leaf spring 230, is rotatably mounted within housing section 204 by a front ball-bearing 232 enclosing the front tubular section 211 of sleeve unit 210, and a rear ball-bearing 233 enclosing the rear tubular section 212 of the sleeve unit. As in the embodiment of FIGS. 1-8, the rear ball-bearing 233 is enclosed by a collar 237 having a vibration-absorbing O-ring 238, and the front ball-bearing 233 is enclosed by a similar collar and vibration-absorbing O-ring (not shown), corresponding to collar 35 and O-ring 36 in FIG. 2.
Chuck unit 220 (FIG. 12) is axially displaceable with respect to sleeve unit 210 in order to contract or expand the open end of the front tubular section 221 of the chuck unit to its clamping and releasing positions, respectively, with respect to the dental tool 205. For this purpose, the external threads 225 of chuck unit 220 terminate short of the enlarged-diameter juncture section 223 to define a recessed section 225a between sections 223 and 225 of the chuck unit, as seen particularly in FIG. 12. Recessed section 225a permits axial displacement of chuck unit 220 with respect to sleeve unit 210 when actuating the chuck unit to its releasing condition.
The axial displacement of chuck unit 220 is effected by a pair of diametrically-opposed cam surfaces 228 formed at the rear end of the rear tubular section 222 of chuck unit 220 engageable with a part of the push-button assembly 206 at the rear of housing section 204. Thus, as shown particularly in FIGS. 11 and 12, push-button assembly 206 includes a push-button 261 and a coupling member 262 aligned with the rear tubular section 222 of chuck unit 220. Coupling member 262 is formed with a pair of diametrically-opposed cam surfaces 263 engageable with cam surfaces 228 of the chuck unit such that the axial displacement of the coupling member by depressing push-button 261 effects a rotary displacement of the chuck unit.
Coupling member 262 further includes a plurality of pairs of diametrically-aligned openings 264; that is each opening of each pair is aligned with the other opening of the respective pair at diametrically opposite sides of coupling member 262. Coupling member 262 further includes a pair of pins 265 adapted to be passed through a selected pair of openings 264 on the opposite sides of coupling member 262. Pins 265 are in turn adapted to be received within the elongated slots 218 in the rear tubular section 212 of sleeve unit 210 so that, during the rotary displacement of the chuck unit 220 by coupling member 262, the movement of the coupling member 262 will be constrained to a linear axial path, as will be described more particularly below.
While coupling member 262 includes a plurality of pairs of diametrically-aligned openings 264 as shown in FIG. 12, only one such pair of openings is used at any particular time for receiving pins 265. Thus, each pair of openings 264 is slightly displaced in the axial direction with respect to the other pairs of openings. Such an arrangement, wherein pins 265 may be received in a selected pair of openings, permits the pins to be precisely located axially with respect to the elongated slots 218 formed in sleeve unit 210. As described more particularly below, pins 265 are movable within slots 218 not only to constrain the movement of coupling member 262 to a linear axial path, but also to permit axial displacement between units 210 and 220 only enough to actuate chuck unit 220 to its clamping and releasing positions.
Push-button assembly 206 includes, in addition to push-button 261 and coupling member 262, a cap 266 for applying the push-button assembly to the rear end of housing section 204, and a bowed leaf spring 267 engageable with the rear tubular section 212 of sleeve unit 210, to bias the push-button 261 outwardly of the housing section.
The clamping device in the handpiece illustrated in FIGS. 10-13 may be operated as follows:
When a dental tool 205 is received within chuck unit 220 as shown in FIG. 11, spiral leaf spring 230, having its opposite ends coupled to chuck unit 220 and sleeve unit 210, respectively, rotates the chuck unit with respect to the sleeve unit in the direction axially moving the sleeve unit 210 to bring its tapered surface 214 against tapered surface 224 of the chuck unit, and thereby to firmly clamp the dental tool 205 within the chuck unit. As in the previously described embodiments, the operation of the dental handpiece causes the two units 210 and 220 to be rotated in the direction tending to tighten the spiral leaf spring 230, and thereby to more firmly clamp the dental tool 205 within chuck unit 220.
When it is desired to remove the dental tool 205, e.g. to replace it with another type of dental tool, push-button 261 of the push-button assembly 206 is manually depressed by the user's thumb. Manual depression of push-button 261 moves couping member 262 axially (leftwardly in FIGS. 11 and 12) such that cam surfaces 263 of the coupling member engage cam surfaces 228 of the chuck unit 220 to thereby rotate the chuck unit with respect to the sleeve unit in the direction producing a stress in spiral leaf spring 230. During the rotation of the chuck unit, the interengaging threads 215 and 225 of the sleeve unit and chuck unit, respectively, cause the chuck unit also to move axially relative to the sleeve unit. In addition, pins 265 of coupling member 262, being received within elongated slots 218 of the sleeve unit 210 constrain the movement of coupling member 262 to a linear, axial movement. The axial movement of chuck unit 220 is in the opposite direction from that biased by the spiral leaf spring 230, i.e. leftwardly in FIG. 11, so as to disengage tapered surface 214 of the sleeve unit from tapered surface 224 of the chuck unit, thereby permitting the open end of the chuck unit to move to its releasing position with respect to the dental tool 205.
The chuck unit is thus held in its releasing position so long as push-button 261 remains depressed. As soon as the push-button is released, spiral leaf spring 230 returns chuck unit 220 to its normal clamping position with respect to sleeve unit 210 by the engagement of tapered surfaces 214 and 224.
In the dental handpiece illustrated in FIGS. 10-13, the dental tool is thus, as in the previously-described embodiment, also very securely clamped within the chuck unit 210 such as to prevent the possibility of accidental release of the dental tool during the high-speed operation of the handpiece. However, in the embodiment of FIGS. 10-13, only a relatively lighter finger-pressure is necessary to depress the push-button 261 in a manner to release the dental tool whenever desired, since the axial force applied by the finger to push-button 261 is multiplied by radius of the coupling member 262 which transfers the axial force to the chuck unit 220 via cam surfaces 263 and 268 (FIG. 12).
The Embodiment of FIGS. 14 and 15
FIGS. 14 and 15 illustrate a clamping device similar to that of FIGS. 10-13 but which avoids the friction produced between the cam surfaces 263 and 228 when depressing the push-button in order to release the dental too, and thereby further reduces the finger-pressure necessary for this purpose.
The clamping device illustrated in FIGS. 14 and 15 thus also includes a sleeve unit, generally designated 310, and a chuck unit, generally designated 320, of similar construction as sleeve unit 210 and chuck unit 220 in FIGS. 8-10. For purposes of brevity, those elements in the two units 310 and 320 which are of substantially the same structure as in the clamping device of FIGS. 8-10 are identified by the same reference numerals, and those elements which differ from the clamping device and FIGS. 8-10 are identified by reference numerals in the “300” series. In addition, the push-button assembly used in the clamping device of FIGS. 14 and 15 is also substantially the same as push-button assembly 206 illustrated in FIG. 11, except for the coupling member 262. Accordingly, in FIG. 15, all the inner surface of push-button 261 is shown, being schematically indicated by line 261, and the coupling member between the push-button 261 and the sleeve unit 310 and clutch unit 320 (corresponding to coupling member 262 in FIG. 12) is indicated by the reference numeral 362 in FIG. 15.
One important difference in the coupling device illustrated in FIGS. 14 and 15 is that the rear tubular section, shown at 312 in FIG. 14, is formed on each of its opposite sides with an elongated angular or spiral slot 318, rather than with a linear axial slot 218 (FIG. 13) for receiving the pins 365, corresponding to pins 265, in the coupling member 362. Thus, as will be described below, when coupling member 362 is pushed by push-button 261, pins 365 moving within slots 318 will produce a rotary force between the coupling member and sleeve section 312.
Another change in the coupling device of FIGS. 14 and 15 over that of FIGS. 10-13 is that the outer face of the coupling member 362, facing the push-button 261, is of a curved, preferably semi-circle, configuration, as shown at 362a in FIGS. 14 and 15. As will be described below, this produces a low friction when coupling member 362 is rotated with respect to the push-button 261 during the depression of the push-button.
A further change in the construction of the coupling device illustrated in FIGS. 14 and 15 is that the rear end 322 of chuck unit 320 and the front end of coupling member 362 facing the rear end of chuck unit 320 are formed with interengaging surfaces which permit axial displacement, but not rotary displacement, of the chuck unit relative to the coupling member. Thus, as shown particularly in FIG. 15, these interengaging surfaces include axially-extending fingers 363 formed in coupling member 362 receivable within, and axially movable with respect to, axially-extending slots 328 formed in the rear section 322 of the chuck unit 320.
The manner of operation of the coupling device illustrated in FIGS. 14 and 15 will be apparent from the above description. Thus, when the push-button (schematically indicated by line 261 in FIG. 15) of the push-button assembly 206 is depressed, its flat surface applies an axial force to the rounded surface 326a of coupling member 362. This axial force is applied by pins 365 to the rear section 312 of the sleeve unit 310 via slot 318 in which the pins 365 move. Because of the angular or spiral formation of slots 318, this axial force is converted to a rotary force applied between the sleeve unit 310 and the coupling 362. This rotary force applied to sleeve unit 310 is in a direction tending to further tighten the spiral spring (230, FIG. 11). In this condition, the sleeve unit 310 cannot further rotate, and therefore this rotary force rotates the coupling member 362. As noted above, coupling member 362 is coupled to the chuck unit 320 by fingers 363 of coupling member 362 receivable within, and axially movable with respect to, slot 328 of chuck unit 320, which permit axial displacement, but not rotary displacement, of the chuck unit relative to the coupling member. Accordingly, the rotary force applied by coupling member 362 will effectively rotate clutch unit 320 with respect to the sleeve unit 310, such that the interengaging threads of the clutch and sleeve unit (shown at 215 and 225, respectively, in FIG. 11) produce an axial displacement of the chuck unit to its releasing position with respect to the sleeve unit.
In all other respects, the clamping device illustrated in FIGS. 14 and 15 is constructed, and operated, in the same manner -as described above particularly with respect to the clamping device of FIGS. 10-13.*
While the invention has been described with respect to two preferred embodiments, it will be appreciated that these are set forth merely for purposes of example, and that many other variations, modifications and applications of the invention may be made.
Patent Application
20070087306
