GB1578659A

GB1578659A - Headpiece for incorporation in an angled dental handpiece

Info

Publication number: GB1578659A
Application number: GB2077477A
Authority: GB
Original assignee: Kaltenbach and Voigt GmbH
Current assignee: Kaltenbach and Voigt GmbH
Priority date: 1976-06-11
Filing date: 1977-05-17
Publication date: 1980-11-05
Also published as: CH615338A5; JPS5436792B2; IT1077245B; FR2354082B1; AT351148B; DE7618616U1; FR2354082A1; ATA345377A; JPS52152688A

Abstract

The reception sleeve (19) of the right-angle head is placed on an intermediate driving sleeve (3) whose end remote from the head projects out of the reception sleeve. At a distance from the pushed-in end (19a) of the reception sleeve (19) the outer wall of the intermediate driving sleeve (3) and/or the inner wall of the reception sleeve (19) has a depression (24) in which there is a spring member (25) which rests radially against the two sleeves (3, 19) and braces the latter against one another. By means of the spring member arranged inside the reception sleeve it is possible to achieve a bracing, which cannot be loosened unintentionally, of the two sleeves. <IMAGE>

Description

(54) A HEADPIECE FOR INCORPORATION IN AN ANGLED DENTAL HANDPIECE (71) We, KALTENBACH & VOIGT GMBH & CO., a German Kommanditgesellschaft of Bismarckring 39, 7950 Biberach, Riss, Germany (Fed. Rep.), do hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a headpiece for incorporation in an angled dental handpiece and comprising a housing; a drive sleeve rotatably mounted in said housing; means provided in said drive sleeve for receiving drivingly the shank of a dental instrument; a receiving sleeve provided by said housing; a further sleeve releasably mounted in said receiving sleeve; a drive shaft rotatably mounted in said further sleeve and having a driving connection with said drive sleeve; and means connecting said further sleeve to said receiving sleeve so as to resist relative axial and rotational movement taking place between said further sleeve and said receiving sleeve.

A headpiece of the above type is known from German Specification No. 2 123 799. In the case of this known headpiece, a locking pin connects together the receiving sleeve and the further sleeve and comprises a screw extending through the receiving sleeve and screwed into a radial thread aperture in the further or intermediatesleeve. Die to this arrangement, the screw so acts on the intermediate sleeve that suitable guiding of the intermediate sleeve in the receiving sleeve is not achieved; on the contrary, the intermediate sleeve may "wobble" in the receiving sleeve, whereby undesirable rapid wear occurs, in particular of the intermeshing elements between the drive shaft and the drive sleeve e.g.

a drive pinion and a spur gear.

A headpiece of the above type is known also from German Utility Model No.

7 343 580. In this case, rhe locking pin is constituted by an outer, radial projection on the intermediate sleeve which engages with a bayonet slot, extending from the end of the receiving slot, of the receiving sleeve, there being associated with the receiving sleeve a cap ring (or screw collar ring) the inner walls of which are formed with a recess for engagement of the projection, and the depth of the recess decreasing gradually in the peripheral direction of the cap ring, at yeast towards one side. The cap ring can be tightened by simple rotation and in this case, due to the fact that abutment of the projection against the base of the recess becomes progressively tighter, tightening of the intermediate sleeve, of the receiving sleeve and of the cap ring relative to each other occurs.It is true that with this arrangement, in many cases the risk of "wobble" of the intermediate sleeve in the receiving sleeve can be diminished, but it may happen that the cap ring is unintentionally rotated, whereby the tightening is loosened.

Additionally, the cap ring constitutes a component which enlarges the diameter of the receiving sleeve and which is disturbing to the dentist operating with a dental handpiece having such a headpiece. To this must be added the fact that the bayonet slot extending from the end of the receiving sleeve weakens the rigidity of the receiving sleeve and causes undesirable widening-out of the receiving sleeve from the end thereof.

A somewhat different headpiece, i.e. a headpiece having no locking pin, is known from German Auslegeschrift No. 1 018 190. In this case, instead of a locking pin one end of the intermediate sleeve is formed with an external screwthread and the end of the receiving sleeve facing the intermediate sleeve is tapped.

These two screw threads are screwed to each other for releasable connection of the intermediate drive sleeve with the headpiece. Here again, there is an unreliable mode of connecting the two elements which leads to "wobble" of the elements connected with each other, since the screwthreads are prwided only in the relatively short end element or end portion of the elements to be screwed to each other.

It is true that the threads at the said ends could be designed to be longer, but then this involves an increase in the risk (already present) that the threads may be damaged, whereby engagement is rendered impossible.

According to the invention there is provided a headpiece for incorporation in an angled dental handpiece and comprising: a housing; a drive sleeve rotatably mounted in said housing for driving a dental instrument; means provided in said drive sleeve for receiving drivingly the shank of the dental instrument; a receiving sleeve provided by said housing; a further sleeve releasably mounted in said receiving sleeve; a drive shaft rotatably mounted in said further sleeve and having a driving connection with said drive sleeve; means connecting said further sleeve to said receiving sleeve so as to resist relative axial and rotational movement taking place between said further sleeve and said receiving sleeve; a spring acting radially outwardly on said receiving sleeve and radially inwardly on said further sleeve so as to secure the sleeves to each other;; and means housing said spring and provided in at least one of said receiving sleeve and said further sleeve.

In an embodiment of the invention, the housing means comprises a recess which does not extend through the associated sleeve and as there is no slot extending through the sleeve in spaced relationship relative to the free sleeve end, it becomes possible to avoid a design which would bring about deformation or widening-out of the sleeve concerned. Since the recess is in the receiving sleeve and/or the further sleeve, a disturbing component which enlarges the diameter becomes superfluous. Finally, the spring may comprise a spring element formed for example from hardened flat strip steel, so as to bring about reliable tightening (or securing) of the hvo sleeves, and the tightening (or securing) cannot be unintentionally loosened due to arrangement of the spring element within the receiving sleeve and/or the further sleeve.

As known per se, the connecting means may comprise a locking pin designed as a screw extending through the receiving sleeve and screwed into a radial threaded aperture in the further sleeve, which guarantees achievement of the engagement dimensions of the further sleeve and the receiving sleeve and also takes up any overload which may occur; furthermore the head of the locking pin is expediently countersunk in an aperture formed therefor in the receiving sleeve.

The recess which may be produced by milling-off, or annular recessing, may extend over the entire periphery of the walls of the sleeves or also over only a portion of the periphery of the walls.

Especially satisfactory securing may be achieved if the recess is arranged with a small degree of axial spacing relative to the headside end of the associated sleeve.

The spring may comprise a leaf spring which may extend substantially transversely of the direction of the periphery of the walls or also in the direction of the periphery of the walls.

According to a further embodiment, the spring may comprise a snap ring.

An expedient embodiment consists in that the recess is so arranged that its central radial plane -- related to the longitudinal extent of the recess extending transversely of the periphery of the walls - is offset relative to the axis of the locking pin in the direction transversely of the direction of the periphery of the walls, and with this arrangement, the recess can be arranged between the head-side end of the associated sleeve and the locking pin. Thereby, the result is achieved that the spring and the locking pin each operate in different radial planes, the result of this being further improved guiding and securing of the further sleeve in the receiving sleeve.

Embodiments of the invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side view of an angled dental handpiece incorporating a headpiece according to the invention; Figure 2 is a longitudinal sectional view of the headpiece; Figure 3 to 5 are similar, detail views of alternative constructions of parts of the headpiece; and Figures 6 to 8 are cross-sectional views corresponding respectively to Figures 3 to 5.

The angled dental handpiece or elbow shown in Figure 1 comprises a holding sleeve 1 in which a main drive shaft (not shown) is mounted. Arranged at one end of the sleeve 1 is a shank elbow 2 into which an intermediate sleeve 3 of the anglehead (generally designated 4) is inserted.

The anglehead 4 has a head housing 5 provided with a receiving sleeve 19 in which is mounted an instrument-driving sleeve 6 for receiving drivingly the shank of an inserted dental instrument (not shown), for example a drill. For a torsionally-rigid connection between the shank and the driving sleeve 6, i.e. for driving the shank, the driving sleeve 6 has an inwardly directed, flattened, segment-like projection 6a engaging with a corresponding (also flattened) recess in the shank.

The elbow head 4 is provided furthermore with a tool-holding flap 7 adapted to be pivoted about a holding pin 9, in an annular groove formed in the toolshank. The upper walls 8 of the head housing 5 are formed furthermore with a recess 10 for receiving one end of the tool shank.

The tool or instrument drive sleeve 6 is provided externally with a driving pinion ii which meshes with a spur gear 12 on a driveshaft 13 mounted in the intermediate sleeve 3. The driveshaft 13 is mounted by means of sliding bearings 14, 15 in the intermediate sleeve 3, whereas the drive sleeve 6 is mounted by means of ball bearings 16, 17 in the head 4. The driveshaft 13 has, at its end 3a remote from the head, a driving arrangement 18 designed as a spur gear and projecting out of the intermediate drive sleeve 3, for coupling to the main drive shaft of the central elbow (one end of which is shown schematically in Figure 2).

The intermediate sleeve 3 is secured in the receiving sleeve 19 against relative rotation and axial displacement by a radially extending locking pin 20 designed as a screw. The locking pin 20 extends through a radial aperture 21 formed in the receiving sleeve 19 and is screwed fast to a radial threaded recess 22 formed in the intermediate sleeve 3. The head 23 of the pin 20 is countersunk in the aperture 21.

In spaced relationship relative to the end 19a of the receiving sleeve 19 remote from the head (referring to Figure 2), the inner wall or surface of the receiving sleeve 19 and, referring to Figures 3 to 8, the outer wall or surface of the intermediate sleeve 3 are formed with housing means in the form of a recess 24 in which (according to in particular Figures 6 to 8) there is arranged spring means comprising a spring element 25 bearing radially outwardly against sleeve 19 and radially inwardly against sleeve 3 in order to secure the two sleeves to each other.

Referring to Figures 3 and 6, the recess 24 extends over a portion of the periphery of the outer surface of the intermediate sleeve 3, whereas the recess 24 extends (in the case of the embodiments according to Figures 4, 5, 7 and 8) over the entire periphery of the outer surface of sleeve 3.

As Figures 2 to 5 show, the recess 24 is axially spaced by a small amount, along the common axis B of receiving sleeve 19 and intermediate sleeve 3, from the end of sleeve 3 adjacent to the head 4 (Figure 2). Referring to Figures3, 4, 6 and 7 the spring element 25 may be designed as a leaf spring extending substantially transversely of the direction of the periphery of the walls i.e. longitudinally of the sleeves 3 and 19. However, the leaf spring may also (as Figures 5 and 8 show) extend in the direction of the periphery of the walls. Finally, the spring element 25 may also be designed as a snap ring.

As will be apparent from Figures 2 to 5, the recess 24 possesses, as seen in longitudinal section, the cross sectional shape of a flat rectangle. The recess 24 is, in the case of the embodiment according to Figure 6, designed as external flattening of the intermediate sleeve 3, whereas in the case of the embodiments according to Figures 7 and 8 it is designed as a groove extending about the periphery of the intermediate sleeve 3.

From Figures 2 to 5 it will be seen that the recess 24 is so arranged that its central radial plane R is, relative to the axis A of the locking pin 20, offset in the direction transversely of the direction of the periphery of the walls.

The reference to a central radial plane R concerns, in this case, the longitudinal extent of the recess extending transversely of the direction of the periphery of the walls. Furthermore, Figures 2 to 5 show that the recess 24 is arranged between the head-side end of the associated sleeves 3 or 19 and the locking Pin.

As will be apparent from Figures 2 to 5, the spring element 25 can be rapidly replaced.

for which purpose the screw representing the locking pin 20 is simply released and it is only necessary to pull the intermediate sleeve 3, together with driving shaft 13, out of the receiving sleeve 19, whereupon the spring element 25 is exposed and can be replaced.

As will be evident from the description of preferred embodiments, there is provided a headpiece in which it is possible to secure together the receiving sleeve and the further sleeve without play, without requiring components enlarging the diameter and without slots weakening the receiving sleeve and extending from the end of the latter.

WHAT WE CLAIM ES:- 1. A headpiece for incorporation in an angled dental handpiece and comprising: a housing; a drive sleeve rotatably mounted in said housing for driving a dental instrument; means provided in said drive sleeve for receiving drivingly the shank of the dental instrument; a receiving sleeve provided by said housing; a further sleeve releasably mounted in said receiving sleeve; a drive shaft rotatably mounted in said further sleeve and having a driving connection with said drive sleeve; means connecting said further sleeve to said receiving sleeve so as to resist relative axial and rotational movement taking place between said further sleeve and said receiving sleeve; a spring acting radially outwardly on said receiving sleeve and radially inwardly on said further sleeve so as to secure the sleeves to each other; ; and means housing said spring and provided in at least one of said receiving sleeve and said further sleeve.

2. A headpiece according to claim 1, in which said means housing said spring extends circumferentially throughout a portion of the internal surface of said receiving sleeve and the external surface of said further sleeve.

3. A headpiece according to claim 1, in which said means housing said spring extends circumferentially throughout the entire circumference of the internal surface of said receiv

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. sliding bearings 14, 15 in the intermediate sleeve 3, whereas the drive sleeve 6 is mounted by means of ball bearings 16, 17 in the head 4. The driveshaft 13 has, at its end 3a remote from the head, a driving arrangement 18 designed as a spur gear and projecting out of the intermediate drive sleeve 3, for coupling to the main drive shaft of the central elbow (one end of which is shown schematically in Figure 2). The intermediate sleeve 3 is secured in the receiving sleeve 19 against relative rotation and axial displacement by a radially extending locking pin 20 designed as a screw. The locking pin 20 extends through a radial aperture 21 formed in the receiving sleeve 19 and is screwed fast to a radial threaded recess 22 formed in the intermediate sleeve 3. The head 23 of the pin 20 is countersunk in the aperture 21. In spaced relationship relative to the end 19a of the receiving sleeve 19 remote from the head (referring to Figure 2), the inner wall or surface of the receiving sleeve 19 and, referring to Figures 3 to 8, the outer wall or surface of the intermediate sleeve 3 are formed with housing means in the form of a recess 24 in which (according to in particular Figures 6 to 8) there is arranged spring means comprising a spring element 25 bearing radially outwardly against sleeve 19 and radially inwardly against sleeve 3 in order to secure the two sleeves to each other. Referring to Figures 3 and 6, the recess 24 extends over a portion of the periphery of the outer surface of the intermediate sleeve 3, whereas the recess 24 extends (in the case of the embodiments according to Figures 4, 5, 7 and 8) over the entire periphery of the outer surface of sleeve 3. As Figures 2 to 5 show, the recess 24 is axially spaced by a small amount, along the common axis B of receiving sleeve 19 and intermediate sleeve 3, from the end of sleeve 3 adjacent to the head 4 (Figure 2). Referring to Figures3, 4, 6 and 7 the spring element 25 may be designed as a leaf spring extending substantially transversely of the direction of the periphery of the walls i.e. longitudinally of the sleeves 3 and 19. However, the leaf spring may also (as Figures 5 and 8 show) extend in the direction of the periphery of the walls. Finally, the spring element 25 may also be designed as a snap ring. As will be apparent from Figures 2 to 5, the recess 24 possesses, as seen in longitudinal section, the cross sectional shape of a flat rectangle. The recess 24 is, in the case of the embodiment according to Figure 6, designed as external flattening of the intermediate sleeve 3, whereas in the case of the embodiments according to Figures 7 and 8 it is designed as a groove extending about the periphery of the intermediate sleeve 3. From Figures 2 to 5 it will be seen that the recess 24 is so arranged that its central radial plane R is, relative to the axis A of the locking pin 20, offset in the direction transversely of the direction of the periphery of the walls. The reference to a central radial plane R concerns, in this case, the longitudinal extent of the recess extending transversely of the direction of the periphery of the walls. Furthermore, Figures 2 to 5 show that the recess 24 is arranged between the head-side end of the associated sleeves 3 or 19 and the locking Pin. As will be apparent from Figures 2 to 5, the spring element 25 can be rapidly replaced. for which purpose the screw representing the locking pin 20 is simply released and it is only necessary to pull the intermediate sleeve 3, together with driving shaft 13, out of the receiving sleeve 19, whereupon the spring element 25 is exposed and can be replaced. As will be evident from the description of preferred embodiments, there is provided a headpiece in which it is possible to secure together the receiving sleeve and the further sleeve without play, without requiring components enlarging the diameter and without slots weakening the receiving sleeve and extending from the end of the latter. WHAT WE CLAIM ES:-

1. A headpiece for incorporation in an angled dental handpiece and comprising: a housing; a drive sleeve rotatably mounted in said housing for driving a dental instrument; means provided in said drive sleeve for receiving drivingly the shank of the dental instrument; a receiving sleeve provided by said housing; a further sleeve releasably mounted in said receiving sleeve; a drive shaft rotatably mounted in said further sleeve and having a driving connection with said drive sleeve; means connecting said further sleeve to said receiving sleeve so as to resist relative axial and rotational movement taking place between said further sleeve and said receiving sleeve; a spring acting radially outwardly on said receiving sleeve and radially inwardly on said further sleeve so as to secure the sleeves to each other;; and means housing said spring and provided in at least one of said receiving sleeve and said further sleeve.

ing sleeve and the external surface of said further sleeve.

4. A headpiece according to any one of the preceding claims, in which said receiving sleeve or said further sleeve has first and second ends, said first end being adjacent to said drive sleeve, and said means housing said spring is axially spaced closer to said first end than to said second end.

5. A headpiece according to any one of the preceding claims, in which said spring comprises a leaf spring.

6. A headpiece according to claim 5, in which said leaf spring extends longitudinally of said receiving sleeve and said further sleeve.

7. A headpiece according to claim 5, in which said leaf spring extends circumferentially of said receiving sleeve and said further sleeve.

8. A headpiece according to claim 3, ifl which said spring comprises a snap-action spring.

9. A headpiece according to any one of the preceding claims in which said connecting means comprises aligned radial bores formed in said receiving sleeve and said further sleeve, and a locking pin received in said bores to connect the sleeves together, in which said recess has an axial extent, and a central radial plane passing through said recess is axially spaced from a radial plane containing the axis of said locking pin.

10. A headpiece according to claim 9, in which said recess is located intermediate said locking pin and an end of said receiving sleeve or said further sleeve adjacent to said drive sleeve.

11. A headpiece according to claim 1 and substantially as hereinbefore described with reference to, and as shown in any one of the embodiments illustrated in the accompanying drawings.

12. A dental handpiece incorporating a headpiece according to any one of the preceding claims.