DE102017011629A1 - Blank holder of a dental milling machine - Google Patents

Abstract

The invention relates to a blank holder of a dental milling machine, by means of which a blank (1) can be fastened, wherein the blank (1) has a flat-cylindrical shape with a lateral surface (2), a base surface (3) and a top surface (4) at the transitions from lateral surface (2) to base (3) and from lateral surface (2) to cover surface (4) in each case a radially encircling angle groove (5) is excluded and wherein the two angle grooves (5) each have an axial annular surface (6) , comprising a base body (7), a radial clamping means (8) and a fastening means (9), wherein the base body (7) has a semicircular receiving contour (10) which corresponds to a first lateral surface portion (11) of the blank (1) and in which of the blank (1) can be used without tools, wherein the semicircular receiving contour (10) has an engagement contour (12), which forms a sectional form fit to the radially encircling angle groove (5) t and wherein the base body (7) has a coupling connection (13) by means of which the base body (7) can be coupled to the dental milling machine, wherein the radial clamping means (8) is connected to the base body (7) by means of the fastening means (9), wherein the radial clamping means (8) has a clamping surface (14) which is in a clamping state of the blank (1) with a second lateral surface portion (15) of the blank (1) in a radial pressure contact and wherein the radial clamping means (8) in the clamping state of the blank (1) provides a radial clamping of the blank (1) by means of a radial application of force.

Description

The invention relates to a blank holder of a dental milling machine.

Dental milling machines are used to manufacture various types of dental prostheses, such as dental implants, as well as to manufacture dental crown and bridge molds.

The workpieces used are called blank or blank. These are machined on the basis of electronically predefined data by means of the dental milling machine, with the computer-aided manufacturing process taking place in particular being based on the principles of computer-aided manufacturing (CAM) and computer-aided design (CAD).

The blanks consist in particular of ceramics, metals, metal alloys and plastics, the materials used in some cases have a high hardness, so that when machining large forces are transferred.

For this reason, it is necessary to reliably clamp the blanks in workpiece holders, so-called blank holders.

In the dental milling technique, a flat cylindrical standard shape has been established for the blanks with circumferential angle grooves on the edge sections, that is, the surface transitions from lateral surface to base surface and from lateral surface to cover surface.

Various approaches are already known from the prior art for this purpose.

Widely used are receptacles which comprise the blank in a radially form-fitting manner and also clamp the blank axially at its edge portion by means of a clamping ring which is fastened by means of screws. The disadvantage here is, inter alia, that with each change a large number of screws must be loosened and tightened and that can clog the bearing surfaces of the screw heads with material residues from the machining.

The publication DE 20 2013 103 515 U1 describes a blank holder for a dental milling machine, which is based on an axial clamping of the blank by means of bolts. The blank is in this case first inserted into an annular workpiece holder, wherein a circumferential lower angle groove of the blank rests on an annular projection of the workpiece holder. Subsequently, a likewise annular clamping device is placed on a recess of the workpiece holder and on a circumferential upper angle groove of the blank and secured by a plurality of bolts on the workpiece holder.

The blank is thus completely surrounded by the workpiece holder, wherein this is partially covered in the edge region, so that results in a deteriorated access during processing. Since the forces acting on the axial tension acting largely on the existing between the upper and lower angle groove of the blank ring surface, it is considerably burdened, which is why there is an increased risk of breakage of the blank. A disadvantage of the device described is also the increased amount of time required for the clamping of the blank.

In the publication EP 3 067 013 A1 a further holding device for dental blanks is described. The holding device is in particular of annular design and has along its inner wall a longitudinal groove into which a clamping element designed as a fixing element can be introduced. For bracing the blank in the holding device, adjusting elements, in particular threaded bolts, can be inserted and tightened into radial openings from the outside, so that they disadvantageously act punctiform on the clamping ring.

While avoiding the disadvantages of the prior art, it is the object of the invention to provide a blank holder of a dental milling machine, which allows a reliable and rapid fixation of a blank, which ensures improved access to the blank during processing and which also provides improved protection offers against breaking out of the blanks and is inexpensive to produce.

The object is solved by the features listed in claim 1. Preferred developments emerge from the subclaims.

By means of a blank holder according to the invention a dental milling machine, a blank can be fastened. The blank is a blank. The blank has a flat-cylindrical shape, which is formed from a lateral surface, a base surface and a top surface. At the transitions from lateral surface to base surface and from lateral surface to top surface, a radially encircling angle groove is excluded in each case. The angle groove at the transition from lateral surface to base surface is the lower angle groove and at the angle groove at the transition from lateral surface to top surface around the upper angle groove. The two angle grooves each have an axial annular surface. In a section is thus formed in the sequence of lower angle groove, lateral surface and upper angle groove a hat profile. The blank and the dental milling machine itself are not part of the inventive device.

The described construction of the blanks thus corresponds to the generally customary form, to which most dental milling machines are tuned, so that no specially shaped blanks and no special dental milling machines are required for using the blank holder according to the invention.

The blank holder has a base body, a radial clamping means and a fastening means.

The main body has a semicircular receiving contour, which corresponds to a first lateral surface portion of the blank and into which the blank can be inserted without tools.

The semicircular receiving contour also has a Eingrifffkonture, which forms a sectional form fit to the radially encircling angle grooves. The engagement contour thus thus has the shape of a broad and flat annular groove, the walls of which engage in a clamping state in the radially encircling angle grooves. The height of the walls corresponds approximately to the depth of the angle grooves. Thus, the blank can be kept improved when inserted into the receiving contour of the base body and secured in its position already before the connection of the radial clamping means.

The first lateral surface portion of the blank is thus in a positive contact with the receiving contour after insertion of the blank. Semicircular shape is not limited to a training with an enclosure angle of exactly 180 degrees but also detects deviations, as long as a radial introduction of the blanks in the semicircular receiving contour is possible.

In addition, the base body has a coupling connection, by means of which it can be coupled to the dental milling machine. The coupling connection can be designed differently and is preferably designed as a quick-release system. In the simplest case, the coupling connection can also have only one or more threaded holes. The coupling takes place by means of the coupling connection in most dental milling machines on a movable axis, so that during the processing of the blank, for example in translational and rotary axes relative to the milling tool is movable. The dental milling machine itself is not part of the device according to the invention.

The radial clamping means is connected in a clamping state with the base body by means of a fastening means, wherein the fastening means may be present, for example, as a screw or threaded bolt with nut. The radial clamping means also has a clamping surface, which in the clamping state of the blank is in radial pressure contact with a second lateral surface section of the blank. In the clamping state of the blank, a radial clamping of the blank is provided by means of a radial application of force.

The radial clamping means may have different configurations, in particular as a bracket, strap or Klemmpratzen. The specific training is chosen depending on the material properties of the blanks and the holding forces thus required and the requirements for the accessibility of the tools to the blank. It is crucial in any embodiment of the radial clamping means that it has a radially acting on the blank clamping surface, wherein the clamping surface may also be formed in several parts, such as in paired Klemmpratzen.

The clamping state is effected by tightening the fastening means, wherein the clamping surface of the radial clamping means is placed in the radial pressure contact with the second lateral surface portion. The transmitted by the pressure contact on the blank forces also cause a Druckkraftbeaufschlagung on the semicircular receiving contour, which represents the counter bearing for this purpose.

Both the base body and the radial clamping means are thus only in radial pressure contact with the blank, so that the top surface and the base surface and the axial annular surfaces of the radial circumferential angle grooves of the blank are not in a clamping-pressure contact.

The terms of the first and second lateral surface portion do not denote predefined lateral surface portions of the blank but merely serve to describe that the basic body and the radial clamping means do not simultaneously act on the same lateral surface portion of the blank.

The blank holder according to the invention offers over technical solutions according to the prior art in particular the following advantages.

On the one hand, there is a significant advantage in that the clamping of the blank takes place radially in the blank holder. Since the power transmission thus takes place over the comparatively large lateral surface of the blanks, the distributed Applying force to a larger area than in the axial tension known from the prior art, in which the axial annular surface formed between the upper and lower angle of the blank groove is loaded.

Since the force transmission surface is thus increased in relation to an axial strain, at the same time a better protection against a breakout of the blanks is provided.

On the other hand, it is advantageous that the base surface and the top surface of the blank as well as optionally large portions of the axial annular surfaces of the angle grooves are not covered by clamping devices or other fastening measures. Consequently, there is better access to the base surface and the top surface and depending on the design of the radial clamping means also to parts of the second lateral surface portion during the processing of the blanks. This also means that, for example, tools with shorter lengths can be used, which allows significant cost savings.

Access to the blank is further improved because the blank according to the invention need not be completely enclosed by the blank holder. The first jacket surface section abuts the semicircular receiving contour of the base body, while the radial clamping device only has to be in pressure contact with parts of the remaining jacket surface.

Furthermore, a faster fixation of the blanks is possible because this is not to be fastened with a plurality of adjusting means, in particular bolts. Thus, a faster change of blanks is possible.

Another advantage is that with the same basic body with the same fastening attachments different configurations of radial clamping means, in particular as strap, band or Klemmpratzen are possible, so that the blank holder as a modular kit, comprising the main body, the fastening means and a plurality of radial clamping means as a bracket, as Band and can be designed as Klemmpratzen. With such a modular kit, advantageously a selection of suitable radial clamping means can be made depending on the material properties of the blank, demands on the holding force and requirements for accessibility.

According to an advantageous development of the fastening means is associated with a spring element, with which the radial clamping means is spring loaded.

The spring element is preferably designed as a plate spring, which is pressed against the base body when the fastening means is tightened. By using a spring element, the tension of the radial clamping means can be further improved. In particular, with vibrations that occur during processing of the blanks, thus an additional safeguard against a release of the blank blank blanks is created by permanently maintaining a bias.

According to a further preferred embodiment, the radial clamping means is designed as a bracket.

Preferably, the bracket is shaped such that it corresponds to the second lateral surface portion of the blank. The clamping surface of the bracket, which is in the clamping state of the blanks with the second lateral surface portion in a radial pressure contact, is formed substantially semicircular. The bracket is preferably connected on both sides in each case by means of a fastening means with the base body.

The bracket has a sufficiently high rigidity, in order to ensure a reliable axial position of the blanks even with axial forces acting on the blank during processing. Due to the increased rigidity of the bracket, this can also be used for blanks made of materials with a high strength.

In an advantageous variant, the bracket has a further engagement contour, which forms a further section-wise positive engagement with the radially circumferential angle groove.

According to this embodiment, the bracket thus in the upper and lower region on a projection, which engages in the two radially circumferential angle grooves of the blank. Thus, the blank can be additionally secured positively in particular against axial force effects and held in the predetermined position position.

In another preferred embodiment, the radial clamping means is formed as a band.

Again, as in the case of the formation of the radial clamping means as a bracket, a substantially semicircular clamping surface is formed, which acts radially on the blank. However, the advantage of the embodiment as a band is in particular that this may have a narrow shape and thus provides improved accessibility to the blank. The band has a lower stiffness relative to the bracket and serves to apply the radial force to the second To cause lateral surface portion of the blank for producing the pressure contact between the first lateral surface portion of the blank with the semicircular receiving contour.

Alternatively, the radial clamping means may be formed according to a preferred embodiment of the invention as at least one clamping claw. Preferably, it is a paired arrangement of two clamping claws.

In this case, the clamping surface is reduced compared to the formation as a strap or band, so that the radial pressure contact with the blank is limited to a smaller area. The advantage of using clamping claws is therefore in particular that the second lateral surface section of the blank is exposed in a large area, so that a further improved accessibility exists.

• 1 Schnittansicht des Blank-Halters in Explosionsdarstellung bei Verwendung eines Bands als Radialspannmittel,
• 2 Perspektivische Darstellung des Blank-Halters in Explosionsdarstellung bei Ausbildung des Radialspannmittels als zwei Klemmpratzen
• 3 Perspektivische Darstellung des Blank-Halters in Explosionsdarstellung bei Ausbildung des Radialspannmittels als Band,
• 4 Perspektivische Darstellung des Blank-Halters in Explosionsdarstellung bei Ausbildung des Radialspannmittels als Bügel,

näher erläutert.The invention will be described as an embodiment with reference to

• 1 Exploded view of the blank holder when using a tape as a radial clamping means,
• 2 Perspective view of the blank holder in an exploded view when forming the radial clamping means as two clamping claws
• 3 Perspective view of the blank holder in exploded view when forming the radial clamping means as a band,
• 4 Perspective view of the blank holder in an exploded view when forming the radial clamping means as a bracket,

explained in more detail.

1 shows a first embodiment in a vertical section of the blank holder in an exploded view. The radial clamping device 8th is formed in this embodiment as a band. In the exploded view, a non-strained state is shown; this is the blank 1 on the semicircular receiving contour 10 and the clamping surface 14 not on.

As 1 indicates, indicates the blank to be attached 1 a flat cylindrical shape, consisting of a lateral surface 2 , a base area 3 as well as a cover surface 4 , on. At the transition from lateral surface 2 to base area 3 and of lateral surface 2 to deck area 4 is in each case a radially encircling Winkelelnut 5.1 and 5.2 excluded. The two angle grooves 5.1 and 5.2 also each have an axial annular surface 6.1 and 6.2.

The blank 1 may consist of different, suitable for dental prosthesis or denture molds materials, in particular ceramics, metals, metal alloys or plastics.

The blank holder is made up of a basic body 7 , a radial clamping device 8th and a fastener (in 1 not shown) together. The main body 7 has a semicircular receiving contour 10 on, which with the first lateral surface portion 11 of the blanks 1 corresponds.

In addition, the semicircular receiving contour has 10 an engagement contour 12 on, which consists of two wall projections in the edge regions of the receiving contour 10 is formed. The height of this wall projections corresponds approximately to the depth of the angle grooves 5.1 and 5.2. Thus forms the engagement contour 12 after inserting the blanks 1 into the main body 7 a sectional form fit to the radially encircling angle grooves 5.1 and 5.2.

The main body 7 also has a coupling connection 13 on, by means of which it can be coupled with a dental milling machine.

The radial clamping device 8th has a clamping surface 14 on, which in a clamping state of the blank on the lateral surface 2 of the blanks 1 abuts and thereby in a radial pressure contact to a second lateral surface portion 15 stands. In the clamping state of the blanks 1 gets through the radial clamping means 8th thus a radial strain of the blanks 1 causing a radial Druckkkontakts effected.

The radial clamping device 8th is in the illustrated embodiment as a band, wherein the clamping surface 14 is formed substantially semicircular. Here is the radial clamping means 8th using fasteners which in the sectional view according to 1 not shown, with the main body 7 connected.

A further embodiment of the blank holder according to the invention shows 2 in a perspective view. The radial clamping means 8.1 and 8.2 are here in the form of two clamping claws.

The clamping surface 14 the clamping claws, which in the clamping state of the blanks 1 with the second lateral surface portion 15 is in a radial pressure contact, in each case formed by the inner side surface of the clamping claws. Due to the small area to which the radial pressure contact is limited, the lateral surface is located 2 of the blanks 1 partially free, allowing for improved access to the blank 1 consists.

As fasteners 9.1 and 9.2 here are two screws in conjunction with associated inner threaded pins. For fastening the radial clamping device 8th and thus to provide the Montageendlage the screws in the body 7 inserted and screwed with the inner threaded pins. In addition, in this case spring elements 16.1 and 16.2 are provided, which are formed as plate spring packets. These are also in the main body 7 introduced so that they enclose the screws in the final assembly. The spring elements 16.1 and 16.2 provide an additional protection of the attachment of the blanks, in particular in the case of vibrations 1 ready.

The connection connection 13 is in the embodiment according to 2 formed from a plurality of threaded holes, to which preferably a quick-release system can be connected.

3 shows a further embodiment. Here is the radial clamping device 8th formed as a band, which in the clamping state of the blanks 1 loaded on train and on its inside the clamping surface 14 formed. The clamping surface is in the clamping state in a radial pressure contact with the blank 1 , This is thereby in the semicircular receiving contour 10 pressed, taking from the semicircular receiving contour 10 a radial counterforce on the blank 1 acts. Compared to the embodiment with the two clamping claws according to 2 the radial application of force is distributed over a larger area, whereby the surface pressure is lower with the same force.

4 shows an embodiment in which the radial clamping means 8th is designed as a bracket. The bow is compared to the band after 3 formed as a rigid component, so that the blank is relieved by this embodiment of acting transversely to the radial plane force attacks by the milling tools. This embodiment is thus particularly suitable for applications in which particularly large forces on the blank 1 be transmitted.

In terms of the main body 7 and the fastener 9.1, 9.2 is for the two in the 3 and 4 illustrated embodiments in addition to the 1 and 2 Referenced.

LIST OF REFERENCE NUMBERS

1

bright

2

lateral surface

3

Floor space

4

cover surface

5

angled groove

6

axial ring surface

7

body

8th

Radial clamping means

9

fastener

10

semicircular receiving contour

11

first lateral surface section

12

engagement contour

13

coupling connector

14

clamping surface

15

second lateral surface section

16

spring element

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 202013103515 U1 [0009]
• EP 3067013 A1 [0011]

Claims (6)

Blank holder of a dental milling machine, by means of which a blank (1) can be fastened, wherein the blank (1) has a flat cylindrical shape with a lateral surface (2), a base (3) and a top surface (4), wherein at the transitions of The lateral surface (2) to the base (3) and from the lateral surface (2) to cover surface (4) each a radially encircling angle groove (5) is excluded and wherein the two angle grooves (5) each having an axial annular surface (6) comprising a base body (7), a radial clamping means (8) and a fastening means (9), wherein the base body (7) has a semicircular receiving contour (10) which corresponds to a first lateral surface portion (11) of the blank (1) and into which the blank ( 1) can be used without tools, wherein the semicircular receiving contour (10) has an engagement contour (12), which forms a sectional form fit to the radially encircling angle groove (5) and wherein the base body (7) has a coupling connection (13), by means of which the base body (7) can be coupled to the dental milling machine, wherein the radial clamping means (8) is connected to the base body (7) by means of the fastening means (9), wherein the radial clamping means (8) a clamping surface (14) which is in a clamping state of the blank (1) with a second lateral surface portion (15) of the blank (1) in a radial pressure contact and wherein the radial clamping means (8) in the clamping state of the blank (1) has a radial Provision of tension of the blank (1) by means of a radial application of force. Blank holder after Claim 1 , characterized in that the fastening means (9) is associated with a spring element (16) with which the radial clamping means (8) is spring-loaded. Blank holder after Claim 1 or 2 , characterized in that the radial clamping means (8) is designed as a bracket. Blank holder after Claim 3 , characterized in that the bracket has a further engagement contour, which forms a further sectional positive connection to the radially encircling angle groove (5). Blank holder after the Claim 1 or 2 , characterized in that the radial clamping means (8) is formed as a band. Blank holder after Claim 1 or 2 , characterized in that the radial clamping means (8) is designed as at least one clamping claw.

Images