FR2519267A1 - Rotary food mixer - uses inclined mixer element off-centre to produce rotation in semi-toroidal bowl - Google Patents

Abstract

A mixer of 10-50 litres vol. for small quantities of pastries, etc., comprises a bowl of semi-toroidal shape rotating around its central axis under the influence of the mixing action and without a separate drive motor. In order to promote safety and prevent accident to fingers, the mixer motor gear is housed in a hinged cover over the bowl. The cover is interlocked with the drive motor to prevent possibility of lifting it while the mixer is rotating. A small space at the front of the bowl, i.e. away from the mixer, provides access to a hand to feel the product consistency. Used for mixing of pastries, pizzas, etc. on a small commercial scale.

Description

 Mixing device with tank and rotating mixing arms.

 The invention relates to kneading, kneading or mixing devices with a vertical tank and rotating kneading arms.

 The technical sector of the invention is that of the construction of mixers, kneaders and other mixers of pulverulent or pasty solid products, in particular products having a visco-elastic or plastic texture.

 Devices are known such as kneaders or kneaders comprising a circular-shaped tank, with a curved or spherical bottom, which is open upwards and which rotates around a vertical axis.

 The tank can rotate freely. It is driven either by the friction of the products, or mechanically.

 Known tanks have an arm rotating on its axis, composed of two or three branches of concentric or helical shape, which is rotated around an inclined axis and which plunges into the tank obliquely to its vertical axis. . The arm is connected to a reducer. The reduction arm assembly can be raised manually or mechanically at the end of the mixing cycle.

 The known tanks also comprise a frame which supports the tank and which also supports the mixer arm and the drive thereof which is generally carried out by a motor and a transmission with pulleys and belts and a reduction gear. The frame overflows on one side of the tank and significantly increases the weight of the bulk thereof. Known tanks generally have a tank cover which closes the upper opening thereof during mixing in order to avoid the risk of accidents, in particular the risk of fingers being cut by the rotating arms.

Mixing devices of this known type are described for example in the patent application FR. A. 2.425.805 (WERNER and
PFLEIDERER) and in the FR patent application. A. 2,466,196 (HALLEY
Louis).

 An objective of the present invention is to provide kneading devices, with a rotary tank and arms, having a reduced bulk, in particular kneading devices of small volume, of the order of 10 to 50 liters, which are intended, for example, for kneading. small quantities of dough to make pastries or pizzas and which can be embedded in a laboratory bench or in a work table.

 Another object of the present invention is to provide kneading devices having good security against the risk of injury to the fingers by the kneading arms while allowing the consistency of the dough to be tested.

 The mixer devices according to the invention are of the known type comprising a fixed tz, a tank rotating around a vertical central pivot carried by the frame, which tank has an open upper end and equipped with a cover, and mixing arms which plunge obliquely into the tank and which are rotated.

 The objectives of the invention are achieved by means of a mixer device in which the tank cover is a hollow casing, which contains a geared motor group with a horizontal axis, a bevel gear, which transmits the drive movement of said group to said mixer arms, a support bearing for said mixer arms and an electrical and electronic circuit box provided with an apparent console on the upper face of the cover.

 The cover of the tank is articulated around a horizontal axis carried by said frame and the plane defined by the axes of said motor-reduction unit is of said mixing arms is perpendicular to said axis of articulation.

 According to a preferred embodiment, the gearmotor group is composed of a variable speed direct current electric motor and a reduction gear with planetary gear, and said gear is composed of two bevel gears whose axes form an angle of 1350 and one of the two pinions is made of a self-lubricating material.

 Preferably, the cover comprises an electromagnet with a vertical axis, the lower end of which is flush with the lower face of the bottom of said housing and comes to rest on the top of a soft hell column carried by said frame to maintain the cover closed and the cover includes a switch which simultaneously cuts off the electrical supply to said electromagnet and to the motor of said group.

 The invention results in new kneading, kneading or mixing devices for pasty or pulverulent products having a reduced bulk.

 Thanks to the incorporation into the cover of the gearmotor group driving the mixer arms and all of the electrical and electronic circuits, the overall dimensions in plan are reduced to that of a square in which the upper edge of the tank is inscribed. .

As a result, the kneaders according to the invention can easily be embedded in a cutout of a work surface or of a laboratory pair.

 The mixers according to the invention offer great safety against the risk of injury due to accidental contact of the hands with the mixer arms, thanks to the magnetic suction cup and the proximity sensor fitted to the cover, which prevent the cover from being opened if the motor-reduction unit is not stopped and which prohibit the start-up of the motor-reduction unit until the cover is closed.

 The adoption of a variable speed direct current motor and a planetary reduction gearbox made it possible to eliminate the usual transmission devices with pulleys and belts, thereby saving space and improving efficiency.

 The geared motor unit which equips the kneaders according to the invention makes it possible to obtain at the outlet of the reducer a speed which can vary between 30 and 100 revolutions / minute for kneaders intended for kneading doughs and between 70 and 200 revolutions / minute for mixers intended for mixing powdery products.

 .The following description refers to the appended drawings which represent, without any limiting character, an exemplary embodiment of a mixer device according to the invention.

 Figure 1 is a top view.

 Figure 2 is a vertical section along II-II of Figure 1.

 Figure 3 is a vertical section along III-III of Figure 1.

 Figures 1, 2 and 3 show a device that can be used as a kneader, mixer or kneader for powdery, granular or pasty products.

 This device comprises a fixed frame 1, which is for example a molded frame of light alloy. The frame 1 essentially comprises a sole 2 and a cover support upright 3 which connects the sole to the hinge pin 4 of the cover.

 The contour of the sole 2 has the shape of a broken line visible in FIG. 1. The sole 2 carries a central boss 5 in which a vertical pivot 6 is fixed by a screw 7. The sole 2 has a first lateral appendage 8, intended to support a tank brake 9 visible in Figure 3. It comr carries a second lateral appendage 10, visible in Figure 2, which supports a metal column 11, made of a ferromagnetic material, for example soft iron.

 We see in Figure 2 that the amount 3 is hollow and that it has an internal wall 3a which matches the shape of the tank.

In horizontal section, the internal wall 3a envelops the first quadrant of the tank on only part of it.

 The device comprises a mixing tank 12, of known shape. The tank 12 is of revolution about an axis z zi. It has a bottom in the shape of a half-torus which is extended by frustoconical external walls diverging slightly upwards. The tank 12 has a central sleeve 13, the upper end of which is closed by a plug 14. A self-lubricating ring 15 is engaged in the lower end of the central sleeve with the interposition of a seal 16 made of oil-impregnated felt. The ring 15 is engaged on the central pivot 6.

 A second self-lubricating ring 17 is engaged on the pivot 6. A brake drum 18 is engaged on the ring 17 with the interposition of a seal 19 made of felt impregnated with oil.

 The rings 15, 17 and the drum 18 rotate at the same time as the tank on the fixed pivot 6. The tank is open at the upper end and the opening is delimited by a circular upper edge 20 centered on the axis z zl.

 The tank has a cover 21 which is articulated around the axis 4 carried by the upright 3 of the frame.

 It can be seen in FIGS. 2 and 3 that the cover 21 has the form of a fully closed hollow box, which is delimited by an upper face 22, by a bottom 23 extending over its entire surface, and by four lateral sides 24 The cover 21 serves as a casing which envelops a geared motor unit with a horizontal x xl axis, which is composed of a variable speed motor 25 and a reducer 26 aligned with the motor, which is an epicyclic reduction gear with planetary gears. . The motor 25 is for example a direct current motor. It includes a cooling fan 25a.

 The bottom 23 of the cover has a sheath 27 which serves as a bearing for the kneading device composed of several branches 28 which plunge into the tank and which are mounted on a drive shaft 29 supported by the bearing 27. Self-lubricating linings are interposed between the shaft 29 and the bearing 27.

 The cover 21 contains a gear composed of two bevel gears, a pinion 30 which is keyed onto the end of the output shaft of the gear motor unit and a pinion 31 which is integral with the shaft 29. A dice two pinions is made of a self-lubricating material, for example filled polytetrafluoroethylene or sintered metal.

 We see in Figure 2 that the axis y y1 of the rotating device forms with the axis x xl of the gear motor an angle a = 135 ". We also see in Figures 1 and 2 that the axes x xl and y yl define a vertical plane perpendicular to the hinge axis 4, so that when the cover is raised, the arms 28 are raised at the same time out of the tank without touching the walls of the tank or the central sleeve 13.

 The side walls of the cover have ventilation air passage openings, an air inlet opening 31 located opposite the suction outlets of the motor fan 25a and an air outlet opening 32, located by example, in alignment with motor 25.

 The cover 21 contains an electromagnet 33 composed of a coil 33a and a soft iron core 33b, which is housed and fixed in a housing preferably located along the side opposite the axis 4. The lower end of this electromagnet is at the same level as the lower face of the bottom 23 of the cover and comes to bear on a metal plate 34 fixed to the top of the column 11.

 The electrical supply circuit of the coil 33a passes through a switch 35 carried by the front edge of the cover, which simultaneously controls the electrical supply of the electromagnet 33 and that of the motor 25. When the electromagnet 33 is supplied, it acts as a magnetic suction cup which keeps the cover closed and the force of attraction is such that it is impossible to open the cover without cutting the power supply to the electromagnet and therefore at the same time that of the motor 25 driving the mixing arms providing security against the risk of injury due to accidental contact of the hands with the mixing arms while they are rotating. Additional security is obtained by a metal mass proximity sensor 35 which is installed near the electromagnet 33 facing the plate 34 and the lower end of which is substantially flush with the lower face of the cover bottom 23.

 When the cover 21 is open or ajar, the detector 35 opens an electrical contact which is placed in series in the supply circuit of the motor 25, so that it is impossible to start the latter as long as the cover 21 is not completely closed. The metal column It serves as a magnetic circuit for the electromagnet.

 In the example shown, the tank 12 is not mechanically rotated but it is rotatably mounted on the central pivot 6 and it is driven by the reaction of the products on the walls of the tank.

 As a variant, the output shaft of the geared motor unit carrying the pinion 30 can be extended and the extension can carry a pinion or a friction disc mechanically driving the tank through the upper edge of the latter.

 Figures 1 and 3 show a brake which is supported by the appendage 8 of the base of the frame. This brake comprises a threaded rod 36, which carries at its end a shoe 37 made of leather or any other equivalent material which is pressed against the brake drum 18. A nut provided with a handle 38 is screwed on the end of the threaded rod and bears on the sole 8. The reference 39 represents a bellows for protecting the threaded rod.

 We see in Figure 1 that the cover 21 has in plan, a square or rectangular shape, one side is substantially equal to the diameter of the upper edge of the tank and three sides of which are tangent to the upper edge 30 of the tank.

 The fourth side 24a which is located at the front is preferably set back from the edge of the tank, so that there is a vice space 40 between the edge of the cover and the edge of the tank. The width of this empty space is substantially equal to the width of a hand and allows an operator to engage the hand in the bowl to touch the dough and to assess the consistency of it, which is necessary in the case kneading dough.

 The axis x xl of the geared motor group is parallel to the front side 24a and the geared motor group is located at the rear of the central axis, that is to say on the side of the central axis opposite to the passage 40, so that the operator's hand does not risk coming into contact with the rotating arms 28.

 As a variant, the cover 21 may have in plan the shape of a square the four sides of which are tangent to the upper edge of the tank, so that it completely covers the latter.

 In all cases, the upper end of the column 1 on which the lower end of the electromagnet 33 comes to rest is at a level a few millimeters higher at the upper edge 20 of the tank, so that air can enter or gases can escape from the tank, but that it is impossible to engage the hand between the edge of the tank and the bottom of the cover which extends over the entire surface of the tank except possibly through the opening 40 which is located far enough from the rotating arms to avoid any risk of accident.

 A fluid or spring cylinder 41 is articulated at 41a to the frame and the rod 42 of this cylinder is articulated at 42a to the cover.

When the cover is closed, the fluid or spring is compressed and the stored energy helps to lift the cover during opening. The jack 41 serves to compensate for the weight of the cover due to the presence of the geared motor group, the gear and the mixer arm carried by the cover. The front half of the cover contains a box 43 which contains the electrical and electronic circuits and components necessary for the operation of the mixer. The top of the housing 43 includes a keyboard 44 for controlling the mixer.

 The electronic circuits advantageously comprise a microprocessor coupled to partially permanent memories of the ROM, PROM or EPROM type and partially volatile of the RAM type.

 In addition to the execution program, the permanent memory contains a series of pre-recorded programs, allowing the user to select, by pressing a key on the keyboard, speed sequences and timing choices adapted to certain standard products. The volatile memory allows the user to dial on the keyboard, for each use of the device, the desired sequence of speeds and time delays. A buzzer indicates to the user the end of a cycle. A screen also permanently displays the time remaining before the end of a cycle.

 It can be seen in FIGS. 2 and 3 that the top and the side walls of the cover have, on their internal face, a tone-insulating coating 45 in the part which contains the uoto-reducing group and a thermal insulating coating 46 in the compartment which contains the housing 43. The two compartments of the cover are advantageously separated by a partition 47 in order to thermally isolate the electronic circuits from the hot environment of the engine.

 It can be seen in FIG. 3 that the cover 21 is equipped with an electric bulb 48 which lights up the interior of the tank, near the opening 40.

 In the example shown, the cover 21 has a bottom -23 molded from light alloy with vertical edges and a cover 22 made of plastic, for example laminated resin, which is fixed to the edges of the bottom.

Claims (9)

 1. Kneading, kneading or mixing device for pasty or powdery products, of the type comprising a fixed frame (1), a tank (128 rotating around a vertical central pivot (6) carried by said frame, which tank has an open upper end, fitted with a cover (21) and kneading arms (29) which plunge obliquely into said tank and which are driven in rotation, characterized in that said tank cover (21) is a hollow casing , which contains a motor-reduction unit (25, 26) with a horizontal axis, a bevel gear (30, 31) which transmits the drive movement from said group to said mixer arms (29), a bearing (27) supporting said mixing arms and an electrical and electronic circuit box provided with a keyboard (44) visible on the upper face of the cover.  2. Device according to claim], characterized in that said cover (21) is articulated around a horizontal axis (4) carried by said frame (1) and the plane defined by the axes (x xl, y y1) of said motor-reduction unit and said mixer arms is perpendicular to said axis of articulation (4).  3. Device according to any one of claims to 2, characterized in that said motor-reduction unit is composed of an electric motor (25) with variable speed direct current and of a reduction gear (26) with planetary gear and said gear is composed of two bevel gears (30, 31) whose axes form an angle of 135 and one of the two gears is made of a self-lubricating material.  4. Device according to any one of claims to 3, characterized in that said cover (21) comprises an electromagnet (33) with vertical axis whose lower end is flush with the bottom face of the bottom (23) of said housing and comes to rest on the top of a soft iron column (11) carried by said frame to keep the cover closed and the cover includes a switch (35) which simultaneously cuts off the electrical supply to said electromagnet and to the motor of that group.  5. Device according to claim 4, characterized in that the top of said column (11) is located a few millimeters above the upper edge (20) of the tank.  6. Device according to any one of claims 4 and 5, characterized in that said cover further comprises a metal mass proximity detector (35) which is flush with the underside of said cover facing the top of said column ( 11) and which opens, in the absence of proximity to the column, an electrical contact placed in series in the supply circuit of said motor (25).  7. Device according to any one of claims 1 to 6, characterized in that said cover (21) has in plan a square shape whose side is equal to the diameter of the upper edge (20) of the tank, three sides of which are tangents to said upper edge (20) and the fourth side (24a) of which is parallel to the axis (x xl) of said gear motor group, is located on the other side of the vertical axis (z z1) of the tank and reveals an empty space (40) located above the tank, having a width equal to that of a hand.  8. Device according to any one of claims 1 to 7, characterized in that it comprises a fluid cylinder or spring interposed between said frame and said cover.  9. Device according to any one of claims 1 to 8, characterized in that said frame comprises a sole 2, which carries a central boss (5) in which is fixed a pivot (6) and which further comprises two lateral appendages (8, 10) which respectively carry a tank brake (9) and a metal column (11) and said frame comprises, in addition, a hollow upright (3) which supports an axis (4) of articulation of the cover .