Dental handpiece

Claim 2

A handpiece assembly for a rotatable tool having a shank comprising: elongated tubular housing means adapted to rotatably support the shank therein; drive shaft means rotatably supported in said housing means and extending longitudinally thereof for engagement with and driving of said shank, one end of said drive shaft means being adapted for driving connection to a power source; said drive shaft means including an elongated tubular drive shaft having one end thereof terminating adjacent the front end of said housing means, said one end of said tubular drive shaft being adapted to have the shank of said tool slidably inserted therein; releasable coupling means disposed within said housing means and associated with said drive shaft means for locking said drive shaft means to said shank; said releasable coupling means including a locking member coaxial with and slidably supported within said drive shaft and means nonrotatably connecting said locking member to said drive shaft, said locking member being axialLy slidable relative to said drive shaft means between a tool locking position and a tool release position, said locking member and said shank having cooperating surfaces for effecting a relatively nonrotatable connection therebetween when said locking member is in said locking position; said coupling means further including a sleeve-like member fixedly connected to said locking member and positioned externally of and slidably supported on said drive shaft means, said sleeve-like member being disposed internally of said tubular housing means and actuating means for effecting movement of said locking member into said release position for permitting a tool to be removed from or mounted in said handpiece assembly, said actuating means including an actuating member positioned externally of said housing means and supported for movement relative thereto, and said actuating means being releasably engageable with said sleeve-like member for effecting movement thereof axially of said tubular drive shaft for causing movement of said locking member from said locking position to said release position.

Claim 3

A handpiece assembly according to claim 1, wherein said actuating member is nonrotatably interconnected to said housing means but is axially slidably supported thereon for movement relative to said housing means between first and second positions; releasable brake means coacting between said sleeve-like member and said actuating means for enabling said releasable coupling means and said drive shaft means to be held nonrotatable relative to said housing means, said brake means being normally disengaged for permitting rotation of said drive shaft means when said actuating means is in said first position, said brake means being engaged for preventing rotation of said drive shaft when said actuating means is disposed in an intermediate position located between said first and second positions, and movement of said actuating means from said intermediate position toward said second position causing displacement of said sleeve-like member and said locking member toward said tool release position.

Claim 4

A handpiece assembly according to claim 2, wherein said actuating member comprises a ring positioned externally of said housing means in surrounding relationship thereto and constrained for axial sliding movement relative to said housing means between said first and second position; said brake means including a first brake portion fixedly interconnected to said actuating ring and disposed internally of said housing means, said brake means also including a second brake portion fixedly interconnected to said sleeve-like member, said first and second brake portions being normally axially spaced from one another and maintained in a disengaged position; first spring means coacting with said releasable coupling means for normally resiliently urging same toward said tool locking position; and second spring means coacting with said actuating means for normally resiliently urging same toward said first position.

Claim 5

A handpiece assembly according to claim 3, wherein said first brake portion comprises an actuating sleeve disposed internally of and slidably supported relative to said housing means and fixedly interconnected to said actuating ring, said actuating sleeve being disposed in surrounding relationship to said sleeve-like member and having brake means formed on a rearward axial end thereof, said sleeve-like member having outwardly extending radial projection means formed thereon and normally axially spaced from the rearward axial end of said actuating sleeve, whereby axial movement of said actuating ring from said first position to said intermediate position, causes the rearward axial end of said actuating sleeve to engage the radial projection means of said sleeve-like member for effecting braking thereof.

Claim 6

A handpiece assembly for a rotatable tool having a shank comprising: elongated tubular housing means adapted to rotatably support the shank therein; drive shaft means rotatably supported in said housing means and extending longitudinally thereof for engagement with and driving of said shank, one end of said drive shaft means being adapted for driving connection to a power source; releasable coupling means disposed within said housing means and associated with said drive shaft means for locking said drive shaft means to said shank; said releasable coupling means including a locking member coaxial with said drive shaft means and means nonrotatably connecting said locking member to said drive shaft means, said locking member being axially slidable relative to said drive shaft means between a tool locking position and a tool release position, said locking member and said shank having cooperating surfaces for effecting a relatively nonrotatable connection therebetween when said locking member is in said locking position; actuating means for effecting movement of said locking member into said release position for permitting a tool to be removed from or mounted in said handpiece assembly, said actuating means including an actuating member positioned externally of said housing means and supported for movement relative thereto; said actuating member comprising an actuating ring disposed externally of said housing means and positioned in surrounding but slidable relationship thereto, and means coacting between said actuating ring and said housing means for nonrotatably connecting said actuating ring to said housing means while enabling said actuating ring to be axially slidably displaced relative to said housing means between first and second positions; and disengagable brake means coacting between said actuating means and said releasable coupling means for permitting said coupling means and said drive shaft means to be maintained in a nonrotatable condition relative to said housing means; said brake means including first and second cooperating brake portions on said actuating means and said releasable coupling means. respectively, said first and second brake portions being normally spaced and disengaged from one another when said actuating means is in said first position and said locking member is in said tool locking position.

Claim 7

A handpiece assembly for a rotatable tool having a shank comprising: elongated tubular housing means adapted to rotatably support the shank therein; drive shaft means rotatably supported in said housing means and extending longitudinally thereof for engagement with and driving of said shank, one end of said drive shaft means being adapted for driving connection to a power source; releasable coupling means disposed within said housing means and associated with said drive shaft means for locking said drive shaft means to said shank; said releasable coupling means including a locking member coaxial with said drive shaft means and means nonrotatably connecting said locking member to said drive shaft means, said locking member being axially slidable relative to said drive shaft means between a tool locking position and a tool release position, said locking member and said shank having cooperating surfaces for effecting a relatively nonrotatable connection therebetween when said locking member is in said locking position; actuating means for effecting movement of said locking member into said release position for permitting a tool to be removed from or mounted in said handpiece assembly, said actuating means including an actuating member positioned externally of said housing means and supported for movement relative thereto; said actuating member comprising an actuating ring disposed externally of said housing means and positioned in surrounding but slidable relationship thereto, and means coacting between said actuating ring and said housing means for nonrotatably connecting said actuating ring to said housing means while enabling said actuating ring to be axially slidably displaced relative to said housing means between first and second positions; and disengagable brake means coacting between said actuating means and said releasable coupling means for permitting said coupling means and said drive shaft means to be maintained in a nonrotatable condition relative to said housing means; said brake means including first and second cooperating brake portions on said actuating means and said releasable coupling means. respectively, said first and second brake portions being normally spaced and disengaged from one another when said actuating means is in said first position and said locking member is in said tool locking position.

Claim 8

A handpiece assembly according to claim 5, further including first biasing means coacting with said actuating means for normally maintaining said actuating means and said actuating ring in said first position, and second biasing means coacting with said coupling means for normally maintaining said locking member in said tool locking position.

Claim 9

A handpiece assembly according to claim 6, wherein said first and second brake portions engage one another when said actuating means is moved into a third position disposed intermediate said first and second positions, whereby continued axial movement of said actuating means from said third position toward said second position causes said locking member to be axially moved from said locking position toward said release position.

Claim 10

A handpiece assembly according to claim 7, wherein said drive shaft means includes an elongated tubular drive shaft having one end thereof terminating adjacent the front end of said housing means, said one end of said tubular drive shaft being adapted to have the shank of said tool slidably inserted therein, and said locking member being slidably supported within said drive shaft member and nonrotatably connected thereto.

Claim 11

A handpiece assembly according to claim 5, further including first and second anti-friction bearing means coacting between said housing means and said drive shaft means for rotatably supporting said drive shaft means within said housing means, said first anti-friction bearing means being disposed adjacent the rearward end of said housing means, and said second anti-friction bearing means being axially spaced a substantial distance from said first anti-friction bearing means in a direction toward the front end of housing means but being axially inwardly spaced a substAntial distance from the front end of said housing means; and said drive shaft means including a tubular drive shaft rotatably supported by said second anti-friction bearing means and having an axially elongated tubular portion extending forwardly beyond said first anti-friction bearing means in a cantilever manner for receiving therein the elongated shank of said tool.

Claim 12

A handpiece assembly for a rotatable tool having a shank adapted to the drivingly engaged with said handpiece assembly, said shank having a shoulder adjacent the free end thereof and first and second arcuate sectors projecting outwardly from said shoulder, said first arcuate sector being defined by a substantially diametrically extending plane which projects from the free end of said shank to said shoulder and defines a driven surface so that said first arcuate sector extends through an angle of approximately 180*, and said second arcuate sector being disposed axially between said first arcuate sector and said shoulder and being defined by said first plane and by a second plane which extends substantially transverse to said plane so that said second arcuate sector extends through an angle of approximately 90*, said arcuate sector resulting in the formation of a radially directed recess between said shoulder and said first arcuate sector, the improvement wherein said handpiece comprises: elongated tubular housing means adapted to rotatably support said tool therein; drive shaft means rotatably supported in said housing means and extending longitudinally thereof for engagement with said shank, one end of said drive shaft means being adapted for driving connection to a power source, the other end of said drive shaft means including a tubular drive shaft portion adapted to have the shank of said tool slidably inserted therein; key means fixed to said tubular drive shaft portion and projecting into the interior opening defined thereby for axially locking said shank to said drive shaft means, said key means projected into said opening and extending substantially diametrically thereacross to provide clearance space in said opening to enable said first arcuate sector to be axially slidably moved past said key means, said key means having a width at least slightly less than the width of said recess as defined by said second arcuate sector so as to enable said key means to project into said recess; and releasable coupling means associated with said drive shaft means for nonrotatably connecting said drive shaft means to said shank, said coupling means including a connecting member nonrotatably connected to said drive shaft means and axially slidably movable relative to said drive shaft means between a tool locking position and a tool release position, said connecting member including a projecting portion disposed within the opening defined interiorly of said tubular drive shaft portion and disposed rearwardly of said key means, said projecting portion projecting into said opening no more than approximately the diametrical plane thereof so as to fill approximately one half of said opening, said projecting portion having a driving surface defined by a substantially diametrical plane with said driving surface being adapted to be disposed directly opposite the driven surface on said first arcuate sector; whereby said shank can be slidably inserted into the opening defined in the interior of said tubular shaft portion so that said first arcuate sector slidably moves axially past said key means while said connecting member is maintained in said tool release position, said inward axial movement of said shank continuing until said shoulder substantially abuts said key means, said shank then being rotated approximately 90* relative to said drive shaft means so that said key means projects into said recess for actually interlocking said shaft means to said drive shaft means, and said projecting portion of said connecting member then being moved axially into locking position so as to axially overlap said first arcuate sector for nonrotatably interconnecting said shank to said drive shaft means.

Claim 13

A handpiece assembly for a rotatable tool having a shank adapted to the drivingly engaged with said handpiece assembly, said shank having a shoulder adjacent the free end thereof and first and second arcuate sectors projecting outwardly from said shoulder, said first arcuate sector being defined by a substantially diametrically extending plane which projects from the free end of said shank to said shoulder and defines a driven surface so that said first arcuate sector extends through an angle of approximately 180*, and said second arcuate sector being disposed axially between said first arcuate sector and said shoulder and being defined by said first plane and by a second plane which extends substantially transverse to said plane so that said second arcuate sector extends through an angle of approximately 90*, said arcuate sector resulting in the formation of a radially directed recess between said shoulder and said first arcuate sector, the improvement wherein said handpiece comprises: elongated tubular housing means adapted to rotatably support said tool therein; drive shaft means rotatably supported in said housing means and extending longitudinally thereof for engagement with said shank, one end of said drive shaft means being adapted for driving connection to a power source, the other end of said drive shaft means including a tubular drive shaft portion adapted to have the shank of said tool slidably inserted therein; key means fixed to said tubular drive shaft portion and projecting into the interior opening defined thereby for axially locking said shank to said drive shaft means, said key means projected into said opening and extending substantially diametrically thereacross to provide clearance space in said opening to enable said first arcuate sector to be axially slidably moved past said key means, said key means having a width at least slightly less than the width of said recess as defined by said second arcuate sector so as to enable said key means to project into said recess; and releasable coupling means associated with said drive shaft means for nonrotatably connecting said drive shaft means to said shank, said coupling means including a connecting member nonrotatably connected to said drive shaft means and axially slidably movable relative to said drive shaft means between a tool locking position and a tool release position, said connecting member including a projecting portion disposed within the opening defined interiorly of said tubular drive shaft portion and disposed rearwardly of said key means, said projecting portion projecting into said opening no more than approximately the diametrical plane thereof so as to fill approximately one half of said opening, said projecting portion having a driving surface defined by a substantially diametrical plane with said driving surface being adapted to be disposed directly opposite the driven surface on said first arcuate sector; whereby said shank can be slidably inserted into the opening defined in the interior of said tubular shaft portion so that said first arcuate sector slidably moves axially past said key means while said connecting member is maintained in said tool release position, said inward axial movement of said shank continuing until said shoulder substantially abuts said key means, said shank then being rotated approximately 90* relative to said drive shaft means so that said key means projects into said recess for actually interlocking said shaft means to said drive shaft means, and said projecting portion of said connecting member then being moved axially into locking position so as to axially overlap said first arcuate sector for nonrotatably interconnecting said shank to said drive shaft means.

Claim 14

A handpiece assembly according to claim 10, wherein said connecting member is disposed within said tubular drive shaft portion and is axially slidably movable relative thereto.

Claim 15

A handpiece assembly for a rotatable tool including a shank having an outwardly facing stop surface thereon, comprising: elongated tubular housing means adapted to rotatably support the shank therein; drive shaft means rotatably supported in said housing means and extending longitudinally thereof for engagement with and driving of said shank, one end of said drive shaft means being adapted for driving connection to a power source; stop means fixedly mounted on said drive shaft means and positioned for abutting engagement with the stop surface on said shank for limiting inward axial movement of said shank relative to said drive shaft means whereby external forces applied to said tool are transmitted through said shank directly to said stop means so as to be imposed on said drive shaft means; releasable coupling means disposed within said housing means and associated with said drive shaft means for locking said drive shaft to said shank; said releasable coupling means including a locking member coaxial with said drive shaft means and means nonrotatably connecting said locking member to said drive shaft means, said locking member being axially slidable relative to said drive shaft means between a tool locking position and a tool release position, said locking member and said shank having cooperating surfaces for effecting a relatively nonrotatable connection therebetween when said locking member is in said locking position; biasing means coacting with said coupling means for normally maintaining said locking member in said tool locking position; and actuating means for effecting movement of said locking member into said release position for permitting a tool to be removed from or mounted in said handpiece assembly, said actuating means including an actuating member positioned externally of said housing member and supported for movement relative thereto.

Claim 16

A handpiece assembly for a rotatable tool including a shank having an outwardly facing stop surface thereon, comprising: elongated tubular housing means adapted to rotatably support the shank therein; drive shaft means rotatably supported in said housing means and extending longitudinally thereof for engagement with and driving of said shank, one end of said drive shaft means being adapted for driving connection to a power source; stop means fixedly mounted on said drive shaft means and positioned for abutting engagement with the stop surface on said shank for limiting inward axial movement of said shank relative to said drive shaft means whereby external forces applied to said tool are transmitted through said shank directly to said stop means so as to be imposed on said drive shaft means; releasable coupling means disposed within said housing means and associated with said drive shaft means for locking said drive shaft to said shank; said releasable coupling means including a locking member coaxial with said drive shaft means and means nonrotatably connecting said locking member to said drive shaft means, said locking member being axially slidable relative to said drive shaft means between a tool locking position and a tool release position, said locking member and said shank having cooperating surfaces for effecting a relatively nonrotatable connection therebetween when said locking member is in said locking position; biasing means coacting with said coupling means for normally maintaining said locking member in said tool locking position; and actuating means for effecting movement of said locking member into said release position for permitting a tool to be removed from or mounted in said handpiece assembly, said actuating means including an actuating member positioned externally of said housing member and supported for movement relative thereto.

Claim 17

A handpiece assembly according to claim 12, wherein said shank is formed with a recess extending transversely thereacross and bounded by a pair of opposed stop surfaces, and said stop means projecting into said recess for preventing axial movement of said shank relative to said drive shaft means in either axial direction.