FR2718058A1 - Planetary centrifugal mixer, mixing process for the preparation of dental mixtures and bowls for centrifugal mixer. - Google Patents

Abstract

The present invention relates to a planetary centrifugal mixer intended to receive at least one bucket comprising a bottom and peripheral side walls of generally cylindrical shape, for the preparation of mixtures used in the dental field, of the type comprising a mobile double-arm driven in rotation. around a main axis, said axis comprising at the end of its free ends means for driving a removable bucket holder in rotation, characterized in that one of the free ends has a bucket holder extended by a secondary axis extending perpendicularly to the bottom of the bucket holder and forming with the main axis an angle a of between about 40 and 60 degrees, the other free end comprising a second bucket holder cooperates with a bucket without a central column, the normal to the bottom of said second bucket holder forming with the vertical an angle b equal to or less than a, the mixer further comprising at least one bucket of a first type, having a hollow central column suitable for cooperating with the secondary axis of the first bucket holder, and at least one accessory of a second type of cylindrical shape not having a central hollow shaft.

Description

PLANETARY CENTRIFUGAL MIXER, METHOD FOR

  MIXING FOR THE PREPARATION OF DENTAL MIXTURES

AND BOWLS FOR CENTRIFUGAL MIXER.

  The present invention relates to a planetary centrifugal mixer intended to receive at least one bucket comprising a bottom and peripheral side walls of generally cylindrical shape, for the preparation of mixtures

used in the dental field.

  Known in the state of the art of such mixers, described for example in the French patent

n 90/12904 of the applicant.

  Such a mixer mainly comprises a movable double-arm driven in rotation about a main axis, said axis comprising at the end of its free ends means for driving in rotation a

bucket holder with removable bucket.

  Such a mixer has improved the quality of mixing compared to previous devices. It is

  however essentially suitable for the mixing of alginates.

  For the preparation of other products such as fluid silicones or kneadable silicones, amalgam or cement, such a mixer is not really suitable, and the practitioner must therefore have recourse to another apparatus. The first object of the invention is to provide a versatile device, adapted to the different types of mixtures used in

dentistry.

  To this end, the invention relates to a mixer whose rotary arm has at one of the free ends a bucket holder extended by a secondary axis extending perpendicularly to the bottom of the bucket holder and forming an angle with the main axis between about 40 and 60

  degrees. The other free end has a second holder

  buckets cooperating with a bucket without central column, the normal at the bottom of said second bucket holder forming with the vertical an angle b at most equal to a. The mixer also comprises at least one cup of a first type, having a hollow central column suitable for cooperating with the secondary axis of the first cup holder, and at least one cup of a second type of cylindrical shape not having central hollow shaft. According to a particular mode of implementation, the accessory of the second type consists of a bowl of

oval interior section.

  Advantageously, the accessory of the second type consists of a transparent insert provided with a transverse channel passing through it along the longest axis of the oval section. This transverse channel makes it possible to introduce into the insert predosed capsules (amalgam, cement with glass ionomer) which can effect a movement back and forth in

this channel.

  According to a variant, the accessory of the second type

is made up of a tare.

  According to another variant, the accessory of the second type consists of a small syringe which is introduced

  in an insert also having a channel.

  According to a particular embodiment, the mixer comprises a water tank for feeding at least one nozzle arranged so as to allow the sending of at least one jet of water to the bottom of the bowl, under the powder, near

  of the central column of the bowl of the first type.

  The invention also aims to improve the homogeneity of the mixture, by preventing the formation of lumps. To this end, the invention also relates to a centrifugal mixing process for the preparation of mixtures used in the dental field in a planetary centrifugal mixer, in particular in a centrifugal mixer previously explained, consists in carrying out: - a first sequence of premixing during of which the arm rotation speed is between 100 and 500 revolutions per minute, - to a transition sequence during which the arm rotation speed is between 0 and 50 revolutions per minute, and to a third mixing sequence at during which the speed of rotation of the arm is greater than the speed during the pre-mix sequence. The invention also relates to a bowl for a planetary centrifugal mixer having a ballast of a predetermined weight. This ballast contributes to the aim of the invention relating to the improvement of the homogeneity of the mixture by a

  better balancing of the mixer arm.

  Advantageously, the bowls for planetary centrifugal mixer have an at least partially conical central column provided with a cylindrical coaxial hollow shaft. This configuration of the central column

  helps reduce the risk of lumps.

  Preferably, the bowl according to the invention comprises a removable cover cooperating with the external surface

  from the side wall by an annular skirt.

  A simplified variant consists of a mixer with only one arm in order to be able to introduce the various types of bowls there, the axis of the bucket holder is eliminated, but the annular skirt is reinforced and lengthened. The alginate bowl

  of course retains its central column.

  The invention will be better understood on reading

  the following description, referring to the drawings

  appended o: - Figure 1 shows a schematic sectional view of the movable part of a mixer according to the invention; - Figure 2 shows a longitudinal sectional view of a first type of bowl; - Figure 3 shows a transverse view along AA of said bowl; - Figure 4 shows a sectional view of a first variant of a bowl of the second type; - Figure 5 shows a sectional view of a second variant of a bowl of the second type; - Figure 6 shows a sectional view of a

  third variant of a bowl of the second type.

  Figure 1 shows a sectional view of

  moving parts of the mixer according to the invention.

  The general construction details relating to the double arm (1) and to the drive mechanisms are not described in the foregoing, since they do not differ from an example of embodiment of the mobile parts of the device

  described in French patent 90/12904 of the applicant.

  The moving parts are different from those of the prior art in that the two bucket holders (2, 3) are different in nature. The first bucket holder (2) is constituted by a pinion having a bottom (4) perpendicular to its axis of rotation (5) and comprises a bearing (6). The axis of rotation (5) forms with the axis

  main (7) vertical an angle a of about 45 degrees.

  The opposite free end (8) of the arm (1) supports a second bucket holder (9) having a bottom (10) extended by a longer annular skirt (11). The base (10) is mounted on a rotation shaft (12) by means of a bearing (13). The axis of rotation (14) of the second bucket holder forms with the main axis (7) vertical an angle b of about 30 degrees. In a variant, the bearing can be integrated into the arm, the axis becoming

mobile relative to the latter.

  The second bucket holder (3) has no

central column.

  Figures 2 and 3 show views respectively in longitudinal and transverse section along AA of the first type of bowl, intended to be placed in the

bucket holder (2).

  The bowl consists of a receptacle (15) of cylindrical shape with elliptical section, provided with a central column (16) of elliptical section. A cover (17) having an annular rim (18) is fitted on the outside of the receptacle (15). A hollow shaft (19) coaxial with the column (16) ensures cooperation with the rotation shaft of the mixer arm. For example, the height of the receptacle is 65 millimeters, the radius of curvature between the bottom (20) and the side wall (21) of the bowl being between 6 and 8 millimeters. The central column (16) has a conical upper part (22) ensuring a

  sliding of the powder on its walls during filling.

  The major axis of the column is 26 millimeters and is parallel to the major axis of the side wall (21) of the

  bowl. The minor axis of the column (16) is 12 millimeters.

  The diameter of the hollow tubular shaft (19) is 15 millimeters. One of the cup holders (2, 3) can receive

  calibrated buckets to balance the moving parts.

  These calibrated buckets include a ballast distributed homogeneously relative to the axis of rotation, corresponding to the

  usual doses of product to mix.

  For example, for a mixer capable of preparing from one to four doses of alginates, the charge

  useful varies between 25 and 100 grams.

  The mixer includes a set of tared bowls that can be identified, for example, by a number on the lid indicating the number of doses and their color. For example, for bowls with an empty weight and without ballast of 50 grams: - the first bowl is intended to receive a dose of alginate and water of 25 grams, and comprises a ballast of 75 grams. - the second bowl is intended to receive two doses of alginate and water of 50 grams, and includes a ballast

50 grams.

  - the third bowl is intended to receive three doses of alginate and water of 75 grams, and includes a ballast

25 grams.

  - the fourth bowl is intended to receive four doses of alginate and water of 100 grams, and does not contain

from the east.

  This embodiment ensures constant balancing, regardless of the number of doses prepared. The bowls are filled with powder in advance. At the time of use, water is added by projection of a plurality of jets directed towards the bottom of the bowl near the central column (16). The jets come from a set of nozzles arranged elliptically above the bowl. Their direction is roughly perpendicular to the bottom (more or less 20 compared to normal at the bottom of the bowl, passing through the center of the column). These jets wet an elliptical zone at the foot of the column and bring up the supernatant powder on the

liquid.

  The nozzles are integral with the mixer frame which also includes a housing for positioning

  from the bowl when preparing the mixture.

  The nozzles are supplied by a roller pump or by any mechanical means, for example a manual piston pump, making it possible to dose the quantity of liquid introduced into the bowl. The bowls are prepared in advance by the dental assistant who garnishes them with 1, 2, 3 or 4 doses of alginate powder. They are then stored and water is added just before mixing. Thanks to the nozzles, the water is projected into the bowl under the powder and can thus be distributed and wet the entire surface of the bottom of the bowl, a necessary condition for mixing

of good quality.

  Figure 4 shows a sectional view of a first variant of an accessory for the accessory holder

of the second type (3).

  It consists of a cylindrical device (25) having a transverse channel (26). The transverse channel (26) is partially closed by an annular rib (27). This device allows the introduction of any

  type of capsule (28) including beak capsules.

  The capsule (28) includes amalgam or cement. During operation it is projected from one side to the other of the transverse channel. The violence of the shocks suffered has the effect of pressing the two parts of the capsule against each other, which avoids doing it manually,

  as in conventional devices.

  FIG. 5 represents a view in longitudinal section of a second variant of an accessory for receiving a syringe (29) containing the products (30) to be kneaded. The syringe (29) is closed at one of its ends by a plug (31) and at the other end by a plunger (32) held by a gripping screw (33). The cap and the screw are strongly held by the edges of the bucket holder. Figure 6 shows a sectional view of a

  another accessory for the second type bucket holder.

  The accessory consists of a large syringe (38) which can directly receive the product to be kneaded (37). This mode of implementation makes it possible to remove

  the mixing bowl and the grip spatula.

  The shape of the syringe (3) approximates the

  forms a mixing bowl and avoids blind spots.

  It can be of round or rectangular section, and is blocked directly by the bucket holder (3). It can also be slid into the transverse channel of a device as described with reference to the

previous figure.

  The syringe is closed at one of its ends by a plug (36) and at its other end by a plunger (35) made of rubber or an equivalent material which can take the form of the front part of the syringe by elastic deformation. The piston is actuated by a part provided with stabilizing fins which can replace the

  retaining screw (34) used during mixing.

  The invention is described in the foregoing to

title of nonlimiting examples.

Claims (7)

  1 - Centrifugal mixing process for the preparation of mixtures used in the dental field in a planetary centrifugal mixer, characterized in that a first pre-mixing sequence is carried out during which the speed of rotation of the arm is between 100 and 500 revolutions per minute, to a transition sequence during which the speed of rotation of the arm is between 0 and 50 revolutions per minute, and a third mixing sequence during which the speed of rotation of the arm is greater than the speed during the pre-mix sequence, this continuation of the initial sequence, then of the transition sequence can   possibly be repeated, before the final sequence.   2 - Bowl for centrifugal mixer for implementing the method according to claim 1 characterized in   that it has a ballast of a predetermined weight.   3 - Bowl according to claim 2, characterized in that it has an at least partially conical central column provided with a cylindrical coaxial hollow shaft. 4 - Bowl for planetary centrifugal mixer according to claim 3, characterized in that it comprises a removable cover cooperating with the outer surface   from the side wall by an annular skirt.   - Planetary centrifugal mixer, for the implementation of the method according to claim 1, of the type intended to receive at least one cup comprising a bottom and peripheral side walls of generally cylindrical shape, for the preparation of mixtures used in the dental field , of the type comprising a movable double-arm driven in rotation about a main axis, said axis comprising at the end of its free ends means for driving in rotation a removable bucket holder, characterized in that the one of the free ends has a bucket holder extended by a secondary axis extending perpendicular to the bottom of the bucket holder and forming an angle a of between approximately 40 and 60 with the main axis   degrees, the other free end having a second holder   buckets cooperates with a bucket without central column, the normal at the bottom of said second bucket holder forming with the vertical an angle b equal to or less than a, the mixer further comprising at least one bucket of a first type, having a central column hollow suitable for cooperating with the secondary axis of the first bucket holder, and at least one accessory of a second type of cylindrical shape does   with no central hollow shaft.   6 - centrifugal mixer according to claim 5 characterized in that the accessory of the second type is   consisting of a bowl with an oval inner section.   7 - centrifugal mixer according to claim 6 characterized in that the accessory of the second type is constituted by an insert provided with a transverse channel the   crossing along the longest axis of the oval section.   8 - Centrifugal mixer according to claim 7   characterized in that the buckets include a ballast.   9 - centrifugal mixer according to claim 8 characterized in that the accessory of the second type consists of an insert provided with a channel, into which a syringe plugged at its end and whose piston is held at the other end is introduced by a screw with a diameter greater than the diameter of the syringe, the syringe   being kept fixed and plugged in the accessory. he   - Centrifugal mixer according to any one of claims 5 to 9 characterized in that it comprises a   water tank for supplying at least one nozzle5 arranged so as to allow the sending of at least one jet of water to the bottom of the bowl, near the column central bowl of the first type.