Locking device for detachable connection of dental hand-piece head with adapter

BACKGROUND OF THE INVENTION The present invention relates to a locking device for detachably connecting head portions, including a head and neck cover, to a dental handle handpiece, comprising in one part a handle with an anti-rotation member and a second part to be connected to the first part; for a shank with a counter member for the locking element, further comprising at least one locking member with radially acting engagement means in one part and in the other part to be connected to. a first portion, at least one stop surface having anti-engagement means, and a engagement means actuating member which releases the locked joint when pressed.

In a known locking device of this type according to EP 29,862, the neck of the handle comprises a resiliently elastic annular collar, which in this area forms the surface of the handle and is connected to the surface of the adjacent part of the handle. In the lateral area of ​​the surfaces that touch the head cover, bridges located axially parallel to the ring sleeve are provided, the free ends of which are provided with outwardly directed locking teeth which engage corresponding recesses in the handle sleeve. The locking connection can be unlocked! by grasping the head with the thumb and forefinger in the region of the side of the neck, that is, in a region which practically contacts the head cover and presses against the annular collar. By this deformation of the annular sleeve the guide teeth are disengaged from the recesses.

The arrangement of the elastically elastic annular sleeve and the axially parallel bridges connected thereto with the locking teeth take up a relatively large amount of space on the head in terms of area. In addition, the sleeve acting as the actuating member forms a relatively large visual surface, which must be designed to correspond to the other surfaces of the handle surface and thus become relatively expensive.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved, particularly cost-effective locking device.

Since the most expensive and, in terms of area, the largest part of the locking device, the actuating member, is now associated with the handle handpiece, that is to say the part of the handle which is less frequently used by the physician, the first cost reduction can already be achieved. By transferring the actuator from the head to the handpiece, more space is also obtained in the head portion, which is an advantage that can be used to deliver spray and light to the preparation site. Since the dividing point arranged in the head portion and the handpiece is now arranged much closer to the head cover compared to the previous design, it is possible to achieve further advantages of the technical operator. The connection to the actuator can, although not already assigned to the head, be made in the same manner as the known device, namely the thumb and forefinger gripping the head, and the operator is even more advantageous grasping area with your fingertips with your thumb and forefinger. The locking device is thus easier to operate. Furthermore, it is advantageous in this device that the cutting edge of the head cover and neck provides some support for the fingers when the handles are pulled axially.

to the handpiece, preferably

Further cost reduction can be achieved when a locking member with radially acting engagement means is also assigned. Such an arrangement is not necessary in any case, since smaller locking processes and associated lower loads may be advantageous in certain circumstances, leave the locking member with engagement means on the head.

The locking member with engagement means may be constructed in various ways.

A particularly advantageous design can be achieved when the locking member and engagement means are formed by one or more thin, substantially axially parallel feet to the handle, which with their front ends abut against a suitably formed stop forming the engagement means and can be unlocked when pressing the actuator inward or outwardly arising from a radial presentation.

Such lateral stop blocking requires smaller constructional dimensions compared to radially projecting locking teeth, since the wall thickness of the feet for stopping and thus for blocking can be practically utilized.

The feet can be either self-springing or radially adjustable by the action of a foreign spring. They may be a multi-piece or a one-piece locking member. In the last variant, the feet can be combined by means of a yoke or a sleeve.

Further advantageous embodiments and further embodiments of the invention can be seen from the following description and examples of the embodiments shown in the drawings, in which Fig. 1 shows a complete dental handle with a hose attached. Fig. 2 shows a first embodiment of the head; Fig. 4 shows a first embodiment of a guide sleeve mountable in the handpiece; Fig. 5 shows a first embodiment of the head locking member; Fig. 6 shows a first embodiment of the operating member for the locking member of Fig. 5; 7 FIG. 8 shows a second embodiment of the head lock; FIG. 10 shows a second embodiment of the head lock; FIG. 10 a third embodiment of the head lock; FIG. 12 and 13 show a fourth embodiment of the locking member, FIG. 14 a holding portion for the components shown in FIGS. 12 and 13, FIG. 15 another embodiment of the head with locking member in a schematic illustration; FIG. 16 the locking member shown in FIG. 15, in a front view taken along line 16/16 of FIG. 15, FIG. 17 shows another guide sleeve flush with the head of FIG. 15, FIG. 18 the guide sleeve shown in FIG. another embodiment of the locking member in longitudinal section.

1 shows a handle 1, which is connected to a supply hose 3 by means of a connecting fitting 2. The handle section 4 facing the connecting fitting 2 comprises a drive unit (not shown), for example an electric motor or an air motor. A handpiece 5 as well as a head 6 is connected to the handle section 6 as well as the head 6. The head 6 comprises, as is known, a head cover 6 for receiving a tool (not shown) and a relatively short neck 8.

Further, there is shown a locking member 2 of the locking device described in more detail in the following figures for axially locking the head 6 relative to the handpiece 5.

Giant. 2 shows schematically the head 6 as a single component. The head 6 is a shaft 10 in which the drive shaft 11 for driving the tool is mounted. On the upper side of the shank 10 is a locking tooth 12 having a stop surface 12a; on the underside there is an anti-rotation element formed in the form of an axially parallel projection 13. The relatively short neck 8 has projections 14 arranged on both sides in the axial direction, which in the mounted state, i.e. when the head 6 is inserted into the handpiece 5, which cover or fix the locking device described in more detail below against handpiece 5.

Giant. 3 shows the front part of the handpiece 5 with the head removed

2. The handpiece 5 consists of an outer sleeve 15 and a guide sleeve 16 mounted therein for clamping the shaft 10 of the head 6.

Giant. 4 shows the details of the guide sleeve 16. The substantially cylindrical guide sleeve 16 has an inclined face 17 facing the head 6, with recesses 18 milled on both sides, into which, in the assembled state, the projections 14 engage on both sides (FIG. 2). The groove 19 provided on the upper side of the opening of the sleeve 16 allows the blocking tooth 12 located on the upper side of the head shaft 6 to pass unobstructed when the head 6 is introduced. The diametrically opposed longitudinal slot 20 is opposed to the pivot element. The guide sleeve 26 comprises, on the one hand, a recessed recess 21 extending over approximately half the circumference of the shank, which passes into the recess 22 arranged on both sides, and secondly an axially parallel recess 23 arranged also on both sides of the shank with clamping pins 24 for clamping; holding the locking member 25 shown in FIG. 5.

The locking member 25 is formed by two approximately axially parallel strip sections, which at one end 26a are connected to each other by means of a yoke 27 and at their other ends 26b have receiving holes 28 for clamping pins 24. The locking member 25 consists of a resilient material. is elastically elastic and forms, in the region of transition points from the yoke 27 to the pressing surface sections, the areas of which are indicated by arrows 29. The locking member 25 is displaced over the reamed recess 21 of the sleeve 16, the two lateral spring sections 26 being fixed by receiving holes 28 in the clamping pins 24 of the recess 23. In the assembled state, the pressing surfaces indicated by the arrow 29 in FIG. After insertion of the locking member 25, the actuating member 9 shown in FIG. 1 and again shown as a separate unit in the perspective view of FIG. 6 is finally pushed onto the guide sleeve 16 from above. The approximately U-shaped portion is also elastically elastic and preferably consists of plastic. By means of the two arms 9a, 9b, which form somewhat protruding control buttons on both sides of the surface of the handle housing 1, the handle 1 and the locking member 25 can be deformed in the contact area in the direction of arrow 29 by radial pressing with the thumb and forefinger. the originally semicircular yokes 27 are oval deformed to such an extent that when the head 6 is axially pulled out, the locking tooth 12 is meant such that the locking tooth 12 is in the locked state as shown in FIG. 2 the engaging and abutting yoke 27 can slip !.

1 and 3, which show the locking device in the assembled state, it goes without saying that only when the two arms 9a, 9b of the actuating member 9 are pressed against the yoke 27 of the locking member 25 are deformed to such an extent that the tooth 12 slips beneath the yoke 27 and this can result in the unlocking of both parts of the handle L of the handpiece 5 and the head 6.

Further figures show further, also advantageous embodiments of the locking device. Giant. 7 shows a guide sleeve 30 which is configured to receive the locking member 33 shown in FIG. 7 and the parts 36 of the head 6 shown in FIG. 8. The guide sleeve 30 comprises a recessed recess 31 on the upper side into which it is inserted. the yoke 32 of the locking member 33 shown schematically in FIG. 9. The yoke 32 of the locking yoke 33 is again connected to the lateral spring sections 34, whose ends 34a form a pressing surface for the disengaged locks, and whose other ends 34b form the engagement means for locking.

The shank 35 of the head portion 36. 8, comprises on both sides a first recess 37 which forms the front stop surfaces 38 and starting from the tip edge 39 a second recess 40 and on the upper side a single third recess 41.

To mount the resilient locking member 33, it is inserted from above with the yoke 32 into the recessed recess 31 of the guide sleeve 30. In this position, the recesses 42, 43 arranged and mutually interconnecting the recesses 42, 43 ensure that the ends 34a, 34b of the longitudinally extending spring sections 34 may engage by means of a sleeve. As shown in FIG. 9, the locking member is configured such that the two spring sections 34 converge convergently at their ends 34b. When the part 36 is inserted axially into the guide sleeve, the end ends 34b of the spring sections 34 on both the end stop surfaces 38 of the recesses 37 on the device reach. In this position, the head portion 36 is secured against axial slipping. When pressed against the actuating member 9, which is also in this embodiment, as shown in FIG. 6 and in FIG. 3 The spring sections 34 reach at the points 43 shown in FIG. 9 and on the tilted edge indicated in FIG. 8 by the arrow 38 towards the device. . Upon further pressing, one end 34a may deflect into the recesses 40 and the other ends 34b may slide out of the recesses 37, thereby unlocking.

In order to provide additional protection against unintentional slipping of the head portion 36 even if the actuator 9 is actuated in error, according to the preferred embodiment shown in FIG. 10, the bracket 32 ​​can be provided with a spring extension 44 which engages with the free end 45 with the third recess 41 of the head portion 36, and preferably operates only when a certain axial stroke is reached. Thus, the end 45 of the extension engages only when the part of the head exerts a slight axial stroke in the withdrawal direction, for example in the range of 1 to 2 mm, after the self-locking has been removed.

Giant. 11 to 14 show a third embodiment of a preferred locking device; in this case, the guide sleeve 46 comprises on both sides of the planar surface 48, 48a graduated by a perpendicular stop edge against which the strip-shaped spring elements 49 abut in the assembled state (FIGS. 12 and 13). The tape spring elements 49 have side extensions 50 with radially inwardly directed first projections 51, which in the assembled state abut the stop edge AZ and secure the spring elements 49 against displacement in the axial direction. Also in this embodiment, one end 49a of the spring elements 49 forms the pressing surfaces for said locking device and the other ends 49b also with the radially inwardly directed second projections 52 form engagement means which in the locked state abut the stop surfaces 38 of the recess 37 of the part 36 head (fig. 8). In order to allow engagement of the engagement means by the guide sleeve 46, corresponding recesses 52 and 52 respectively are provided on both sides of the sleeve. slits.

In the assembled state, both spring elements 49 are retained by means of a yoke spring 54 which is inserted into a corresponding milled recess and shown in FIG. 14. Instead of multi-part locking elements, both spring elements 49 and yoke 54 can also be formed in one piece.

Giant. 15 shows an embodiment of a head portion 60 in which the shaft 61 has a circular groove 62 into which a sleeve 63 forming a locking member is inserted. The sleeve 63 shown in FIG. 16 in a front view, it comprises, on the one hand, a longitudinal slot 64 which allows the sleeve to be inserted somewhat extended over the end of the shaft for mounting and possibly secured against rotation, on the other hand by forming multiple slots 65 extending only over a portion of the length of the sleeve 63 on both sides of the collar 63 of the bead 66. the end ends 67 of these spring shoes 66, in the locked state, abut the abutment surfaces 68 of the two locking teeth 69, which are arranged at a distance corresponding to the shaft diameter, on a guide sleeve 70 mountable on the handpiece 5 (FIG. 1). The guide sleeve 70 is designed similarly to the locking and arrangement of the actuator as shown in Figs. 4 and 7. The actuator 71 shown in Fig. 18 is in principle similar to the actuator 9 shown in Figs. 6; however, it still has on both sides retaining arms 71a, which are mounted in longitudinally extending grooves 72 and secured against falling out of the bolt blocks 73 and countersunk bore described above, abutting the control forging device 74. In contrast to embodiments, the member 71 directly on the inclined face Thus, in the locked state, the actuating element 71 lies between the inclined face 76 of the head 60 (FIG. 15) and the inclined face 75 of the guiding sleeve 70. However, the axial stop cb0 of the handle portions forms on the guide sleeve 70 a surface 77 which, in the locked state, abuts on the lower portion of the face 76 of the head portion 60.

As already described in the aforementioned embodiments, an axially parallel locking tooth 78 is provided to secure against rotation on the head portion 60, which engages the guide slot 79 of the guide sleeve 70 when the head portion 60 is inserted onto the handpiece. 78 and guide slot 79 are not arranged on the lower side but on the upper side of the head portion 60 as shown in FIGS. 15, 17, 18 by positions 78¹. 79¹. By placing the handpiece 5 (with the guide sleeve) on the head part 60, an accurate positioning can be achieved, ie functionally correct positioning of the parts to be connected to each other. If the head portion 60 and the handpiece 5 are rotated relative to each other, i.e. not functionally correctly engaged, the inclined front face of the actuator 71 slides below the bearing surface on the locking tooth 78 'and there longitudinally until the locking tooth 78' locks in the slot 79 '.

Said anti-torsion locking of the spring sleeve 63 can be effected by a anti-torsion locking pin arranged on the head shaft 61 and engaging the through slot 64 or by means of a locking tooth 78 or 78 '.

The two spring shoes 66, in their unlocked condition (FIG. 15), at their free ends, strut somewhat outwardly protruding over the diameter of the shaft 61. When the guide sleeve 70 is inserted, the two locking teeth 69 slide along the outer surfaces of the shoes 66 and push them inwards until the ends engage the locking teeth 69. For unlocking, the actuator 71 at the location indicated by the arrow (FIG. 18) presses in somewhat; In this case, the spring shoes 66 are pushed into the free space 80, which is arranged on the shaft 61 for this purpose, so that the head part 60 can be pulled axially away from the sleeve 5 or the guide sleeve 70.

As an alternative to the embodiment of the locking sleeve 63 shown in FIGS. 15 and 16, which has a constant cross-section therein, the locking sleeve 63 may also be formed as shown in longitudinal section in FIG. 19 that the spring shoes are in an unlocked position. In this way, they have locking teeth 81 at their ends provided with inclined leading surfaces.

In this embodiment, too, it is possible to provide an additional safety device against axial slipping of the head with unlocked parts. Such an additional locking fuse may be provided, for example, by a leaf spring mounted on a guide sleeve, the free end of which is provided with a locking tooth which engages with a notch on the shaft. Such an additional fuse - as already mentioned - can advantageously be arranged such that it only operates when both parts of the handle 1, i.e. head and handpiece have a small axial path in the sense of slipping.