EP1122047A1 - Improvements on a bucket mixer - Google Patents

Abstract

the cement mixer has a double helical auger with an inner flute (19) and an external flute (20). The blades of the helical flute are fixed to the inner flute to allow compensation for applied loads. The inner flute has flat sectors which are connected at their ends by a radial section (61). The mixing auger is covered by a grill (25) formed with two wings (26,27) which are folded to release the opening of the mixer.

Description

The present invention relates to mixing buckets which allow the preparation of products of all kinds and more particularly in the public works, the mixing buckets used for manufacture and distribution of concrete.

This type of equipment, described in particular in document FR-2 759 621, is generally associated with a handling machine to which it is linked by an appropriate coupling of the three-point coupling type or other.

This bucket, in the shape of a trough, contains a motorized mixing screw. Its connection system with the machine allows it to be placed in position normal mixing and in this position the opening of the trough is substantially horizontal. It can also be placed in the loading position; in this case the trough is tilted and its front face acts as a shovel.

Filling the trough with basic ingredients such as sand and / or gravel, can be done directly. Indeed, the trough being in tilted position, horizontally, the machine can take sand from a pile, gravel or whatever. The cement can then be introduced into the trough, by the opening, and preferably through a protective grid which covers this opening and on which the operator can deposit and open his or her cement bags.

The mixing operation is carried out by means of a very particular which has two propellers of different diameters but concentric, and whose threads are not inverted. This mixture is discharged preferably through an opening in the bottom of the trough.

The effectiveness of this type of bucket also depends on its ability to perform good mixing and good draining as of its ability to take sufficient products, sand or gravel from a pile.

The present invention provides improvements which allow improve the efficiency of this type of equipment.

The invention therefore relates to a mixing bucket consisting essentially on the one hand, of a trough provided with an opening, one side of which forms the leading edge of the wall acting as a shovel, which trough is provided in its lower part, opposite to said opening, a drain flap, and, on the other hand, a mixing screw of the type with two propellers or turns of different but concentric diameters and whose steps are reversed: an internal propeller mounted on the drive shaft and an external propeller mounted on said internal propeller, which external propeller has a direction which allows the emptying of the products stirred in the trough by said hatch; this bucket also has a retractable protective grid located on the opening. According to the invention, this bucket is characterized in that the external propeller consists of several overlapping blades each fixed on the internal propeller by means of a lug whose characteristic is to form a dihedron with the general surface of the blade; the edge of this dihedron is substantially radial and is located along the length of the peripheral strip of the blade, and in particular in an area upstream of its length which is between 1/6 ^th and 1/3 of the length of said strip, in order to balance the forces exerted on said blade so as to limit its deformation.

Still according to the invention, each blade of the external propeller has - a continuous peripheral band which truly constitutes the portion of propeller, with an external edge which follows the contour of the surface from the bottom of the trough, - a veil which extends towards the center of the propeller, the downstream end of said blade to the edge of the dihedral, and - the tab of fixing which extends upstream of said edge.

According to another arrangement of the invention, the downstream part forming the peripheral strip of the blade, has at least one fold which gives said downstream part a pitch greater than the pitch of the upstream part of the strip device constituting the propeller, in order to accelerate the movement of produced in the bottom of the trough at the end of each blade.

According to another arrangement of the invention, the upstream part of the peripheral band constituting the propeller, is shaped in a point shape to improve the penetration of the blade in the products, and especially for avoid jamming of materials and in particular gravel between the end of the blade and the wall of the trough.

According to another arrangement of the invention, the blades forming the propeller external are angularly offset from each other, by a angle between 110 and 120 °.

According to another arrangement of the invention, the internal helix of the screw of mixing consists of sheet metal sectors, fixed on the central shaft of the screws, which sectors are shaped at their ends to allow their assembly with respect to each other, which assembly is carried out on a radiant portion of a few centimeters, between 3 and 8 cm for example, which portion gives the internal propeller a continuous periphery of a end to end of the tree.

According to another provision of the invention, each constituent sector of the internal propeller represents approximately 1/3 of circumference and it is made up a flat sheet, the ends of which, at the peripheral strip, are folded, forming a dihedral, the edge of which is substantially perpendicular to the radiant portion where the assembly of two adjacent sectors is located.

Still according to the invention, the grid acting as a hatch, above the mixing screw, extends over the entire opening of the trough and it consists of two flaps which are integral with one of the another by means of a joint and which are foldable one on the other; one of the flaps, that located on the front wall of the trough, is articulated on the front edge of the opening and it is operated by means of an appropriate member of the hydraulic cylinder type; the other flap is, on the one hand, articulated on the first flap by means of a hinge situated between their adjacent sides and, on the other hand, guided by means of at least one connecting rod which extends between one of the sides of said flap and the corresponding side wall of the trough.
The choice of a grid formed by two components makes it possible to have a large opening, while benefiting from a small footprint of this grid or hatch in the open position, during the sand and / or gravel loading operation.

Still according to the invention, the anchoring and articulation points of the connecting rod that holds the second flap, are arranged so that they cause almost complete clearance of the opening when the first flap is operated by the jack, which flaps are found in a folded position one on the other, in the extension of the wall front of the trough.

Still according to the invention, the connecting rod is articulated on the side wall of the trough, at a point which is situated approximately halfway down the flap anterior when the latter is in the closed position, and it is articulated on the front flap at a point located substantially 1/3 of the length of this flap front, length taken from the joint interposed between the two shutters.

• la figure 1 est une vue générale en perspective d'un godet malaxeur selon l'invention, vu de dessus depuis l'avant, avec sa grille de protection représentée partiellement et en position ouverte ;
• la figure 2 montre le godet malaxeur, toujours en perspective vu de côté et sur l'arrière, avec la grille de protection en position fermée ;
• la figure 3 montre en perspective, l'arbre de la vis de mélange sur lequel est simplement montée l'hélice interne ;
• la figure 4 montre d'une façon plus détaillée la forme et la liaison des secteurs constitutifs de l'hélice interne de la vis de mélange ;
• la figure 5 montre la vis de mélange avec ses deux hélices ;
• la figure 6 montre en perspective, une pale de l'hélice externe.

The invention will be further detailed with the aid of the following description and the appended drawings, given for information only, and in which:

• Figure 1 is a general perspective view of a mixing cup according to the invention, seen from above from the front, with its protective grid shown partially and in the open position;
• FIG. 2 shows the mixing bucket, still in perspective seen from the side and on the rear, with the protective grid in the closed position;
• Figure 3 shows in perspective, the shaft of the mixing screw on which is simply mounted the internal propeller;
• Figure 4 shows in more detail the shape and connection of the constituent sectors of the internal helix of the mixing screw;
• Figure 5 shows the mixing screw with its two propellers;
• Figure 6 shows in perspective, a blade of the external propeller.

As shown in Figures 1 and 2, the mixing bucket includes, conventionally, a trough 1 which consists of two side walls 2 and 3 and a wall 4 with a U-shaped section, the front or rear part of which is equipped with a coupling system 5 cooperating with a handling; we also notice feet 6 arranged at the bottom of the U-shaped wall, which allow the bucket to be placed on the ground in a normal mixing position, i.e. with its opening partly upper facing up.

The mixing screw 9, centered on an axis 10, extends between the walls 2 and 3. The shaft 11 of this screw is driven for example by means of a motor hydraulic 12 visible in Figure 2, via a transmission suitable housed on the side of the wall 3, in a casing 13.

The lower part 41 of the trough and of the wall 4 is shaped as half cylinder shape. The front wall 42 of the trough extends from the semi-cylindrical part 41 up to the level of the upper rim 14 which forms the anterior side of the trough opening. The front wall 43 of the trough extends between the semi-cylindrical part 41 and the edge 15 of the opening, which edge 15 is parallel to the front edge 14. This wall 43 and its edge 15 in fact form the part which constitutes the bucket shovel and which allows by appropriate manipulation of the bucket, to take products in a pile of sand or gravel for example.

Under the semi-cylindrical part 41 there is, at one of the ends of the trough, the drain pipe 16. This drain pipe comprises a hatch not visible in the figures, operated by means of the jack 17 which appears in Figure 2.

The mixing screw 9 has a first propeller 19 which is secured to the shaft 11 and a second propeller which is made up of several blades 20 fixed on the periphery of the first propeller 19.

The mixing screw 9 will be detailed later in conjunction with the figures 3 to 6.

We simply notice that the blades 20 of the external propeller, taking into account the direction of rotation indicated by arrow 21, propel the products located in the trough, towards the drain 16.

The internal propeller 19, the pitch of which is reversed with respect to that of the blades 20, tends to bring the products away from the orifice of drain 16, that is to say on the side of the drive housing 13.

Several products can be mixed in the trough; they are introduced by the large opening of the trough, which opening is defined by the front edge 14, the front edge 15 and the upper edges 22 and 23 from sides 2 and 3 respectively.

If the bucket is used for concrete preparation, the operator has to pour one or more bags of cement directly in the trough. To prevent any incident and facilitate this operation, the opening of the trough is covered with a grid 25 on which the operator can very well put down his bag.

This protective grid has the particularity of being made up of two flaps 26 and 27. The flap 26 or anterior flap, is articulated in its part rear on an axis 29 located above the front edge 14 of the trough.

This flap 26 is operated by means of a jack 30. This jack 30 is interposed between, on the one hand, a yoke 31 mounted in the center of the part upper of the front wall 42, on a reinforcing beam 32, and other part, a yoke 33 disposed at the end of the flap 26, that is to say on the side 34 of this flap, that which is located substantially in the center of the opening of the trough.

The second flap 27 is articulated by means of hinges 37 on the flap anterior 26 and in particular on its side 34.

Thus, when the flap 26 is raised under the effect of the jack 30, the flap before 27 rocks and folds against said flap 26.

The movement of the flap 27 is controlled by means of the side rods 39 which are interposed between the walls 2 and 3 and the lateral sides 44 of the part 27.

Each connecting rod 39 is articulated on the sides or sides 2 and 3 of the trough at their upper part, around an axis 47 which, as shown in FIG. 2, is located approximately halfway along the side 49 of the flap 26 when it is in closed position.

The other end of the connecting rod 39 is articulated around an axis 50 which about 1/3 the length of the sides 44, from the end front of said flap 27, that is to say the end where the hinges are located 37.

The grid of each of the flaps 26 and 27 is a coarse grid meshes. Note on the flap 27, saw teeth 51 which allow tear a bag like a bag of cement to simplify the opening operation for the person responsible for emptying his bag of cement or other in the trough 4.

The articulation axes 47 and 50 of the connecting rods 39 are positioned such that when the jack 30 is actuated to operate the flap 26, the flap 27 folds down and folds over said flap 26, releasing as much as possible the opening of the trough which facilitates its filling and particularly the removal of products from a pile of sand or gravel by example.

In the open position, as shown in Figure 1, the ends of the sides 44 of flap 27 abut on supports 52 arranged at the upper part of the sides 2 and 3, slightly in front of the axis 29 which constitutes the axis of articulation of the front flap 26.

The length of the flap 26, taken relative to the walls 2 and 3 of the trough, is significantly lower than that of the flap 27. The flap 27 rests actually on the edges 22 and 23 of the sides 2 and 3, at its ends, and on the side or edge 15.

The flap 26 fits between the sides 2 and 3, with a minimum of play.

Figure 3 shows the shaft 11 of the mixing screw on which is mounted the first propeller 19. This first propeller 19 consists of a assembly of sectors 55 which each cover approximately the equivalent of 1/3 in circumference, with the exception of the end sectors 56 and 57 which are particular in the sense that they are shaped to fit the contours and trough shapes at each of its ends.

These sectors 55 are in the form of a flat sheet metal part shaped so that it can be welded at its central part on the shaft 11 and to marry, by its external edge 60 a volume which is less than the overall volume of the bottom of the trough as determined by the semi-cylindrical portion 41 of wall 4.

The edge 60 is continuous between the two ends of the propeller 19. This continuity is constant over a radial height of several centimeters, from 3 to 8 cm for example.

The sectors are fixed at an angle on the shaft 11 and their ends adjacent are assembled on a portion 61 which extends along a radius starting from the tree 11. It is this radial portion 61 which can have a length from 3 to 8 cm for example.

The adjacent sectors 55 are assembled at this portion 61 by folding their ends 62, which ends 62 form with the general surface of sectors 55 a dihedral and the edge 63 of this dihedral is substantially perpendicular to the radial portion 61.

Figure 4 shows from another angle, the assembly of two adjacent ends 62 of sectors 55.

We find the edges 63 of each of the dihedrons formed by these end portions 62 and the general surface of the sectors.

These breaks on the peripheral band of the propeller 19 cause speed variations in the movement of products and favor mixed.

Figure 5 shows the complete mixing screw i.e. its internal propeller 19 and blades 20 forming the external propeller, mounted on said propeller 19. The envelope of the outer propeller corresponds to the semi-cylindrical casing of the bottom of the trough 4.

The blades 20 overlap, that is to say that the space swept by each of them is partially taken up by the following blade.

The angular difference between two consecutive blades 20 is less than 120 °, it is for example between 113 and 116 °. This angular shift promotes mixing.

The blades 20 are shaped in a piece of sheet metal. They have - a peripheral strip 120 which truly constitutes the propeller portion, - a central sail 121 and - a fixing lug 122. The blades 20 are preferably removable; they are assembled by their tab 122 on sectors 55 by means of bolts not shown.

The peripheral strip 120 and the web 121 are located substantially in the same general flat surface while the tab 122 is folded by relative to the web 121, forming a dihedral whose edge 123 is substantially radial, that is to say it passes close to the axis of the shaft 11.

The angle of the dihedral at the edge 123 depends on the pitch given to each propeller; it is of the order of 135 ° for example.

Note that the peripheral strip 120 extends beyond the edge 123, on the side of the tab 122, that is to say in the upstream part of the blade. The portion 124 of the strip 120, which is located upstream of the edge 123, has a length which is for example between 1/3 and 1/6 of the length total of said strip, so that said edge 123 is also located in a zone Z which extends in the same proportion.

The upstream end of part 124 of the peripheral strip is shaped into a point. This point 125 avoids the jamming of the aggregates between the blade and the wall of the trough.
This point 125 also constitutes a wear indicator for the blades.

The downstream end of the peripheral strip 120 may include as detailed in Figure 6, two folds which give the downstream end of the paddles a step progressively larger than the rest of the strip peripheral.

The first folding, around the axis 126, forms a dihedral whose angle is of the order of 174 ° for example. The second folding at the downstream end of the strip, along axis 127, forms an angle which may be identical to the previous one, of the order of 174 °.

The axis 127 is located approximately at a distance from the end downstream 129 of the strip 120 which corresponds to 1/8 of the length of the said bandaged. The axis 126 is located for example at a distance from the axis 127 which is the order of ¼ of the total length of the strip 120.

The two successive folds with a larger step tend to cause an acceleration of the product in the bottom of the trough and a better recovery by the next blade.

The first blade 20 ', located at the end of the shaft 11 on the side of the transmission, is fixed directly by means of a lug 130 on the shaft 11.

We also note the absence of blades 20 in the area which corresponds to the drain hatch.

The last blade, on the side of the drain hatch, which is part of the sector 55 ', brings back in fact the products which get lost at the end of the trough, towards the center of the trough.

Claims (10)

Mixing bucket consisting on the one hand, of a trough (4) provided with a opening of which one side forms the leading edge of the wall (43) serving shovel, which trough (4) is provided in its lower part, opposite to said opening, a drain hatch (16) and, on the other hand, a screw mixture (9), of the type with two concentric turns or helices of diameters different and whose steps are reversed: an internal propeller (19) mounted on a drive shaft (11) and an external propeller mounted on said propeller internal, which external propeller has a direction which allows the emptying of the products brewed in the trough, by said hatch, which bucket still has a protective grid (25), retractable, located on the opening, characterized by that the external propeller consists of several overlapping blades (20), each fixed on the internal propeller (19) by means of a lug (122), the particularity is to form a dihedral with the surface of the blade and particular of its veil (121), the edge (123) of this dihedron being substantially radial, i.e. it passes through the axis of the shaft (11), and is located on the length of the peripheral strip (120) of the blade and in particular in a upstream zone of the length of this strip, which is between 1/6 and 1/3 of the length of said strip. Mixing bucket according to claim 1, characterized in that each blade (20) of the external propeller comprises - a peripheral strip (120) continuous, which truly constitutes the portion of the propeller, with a external edge which follows the contour of the surface of the bottom of the trough, - a sail (121) which extends towards the center of the propeller, from the downstream end of said blade to the edge (123) of the dihedral and - a fixing lug (122) which extends upstream of said edge (123). Mixing bucket according to claim 2, characterized in that the downstream part of the peripheral strip (120) of each blade (20) comprises at minus a fold which gives said downstream part a pitch greater than the pitch of the upstream part of the peripheral strip constituting the propeller, which folds forms a dihedral whose angle is of the order of 174 °. Mixing bucket according to claim 2, characterized in that the upstream part of the peripheral strip (120) is shaped in a point shape (125). Mixing bucket according to any one of Claims 1 to 4, characterized in that the blades (20) forming the external propeller are offset angularly relative to each other, at an angle between 110 and 120 °. Mixing bucket according to any one of Claims 1 to 5, characterized in that the internal propeller (19) of the mixing screw consists sheet metal sectors fixed to the central shaft (11) of said mixing screw, which sectors (55) are shaped at their ends to allow their assembly with respect to each other, which assembly is carried out on a radiant portion (61) of a few centimeters, between 3 and 8 cm by example, which portion gives the internal propeller a continuous periphery, from one end to the other of said shaft (11). Mixing bucket according to claim 6, characterized in that each sector (55) represents approximately 1/3 of circumference, and in that it consists of a flat sheet whose ends (62), at the level of the strip peripheral, are folded, forming a dihedral whose edge (63) is substantially perpendicular to the radiant portion (61) where takes place the assembly of two adjacent sectors. Mixing bucket according to any one of Claims 1 to 7, characterized in that the grid (25) serving as a hatch, above the mixing screw (9), extends over the entire opening of the trough, which grid is consisting of two flaps (26, 27) which are integral with each other at means of articulations (37), and are foldable one on the other, one of the flaps, the flap (26) located on the side of the front wall (42) of the trough, being articulated on the anterior edge (14) of the opening, and being maneuvered by means of a suitable member, such as a hydraulic cylinder (30), the other flap (27) being, on the one hand, articulated on the flap (26) and, on the other hand, guided by at least one connecting rod (39) which extends between one of the sides of said flap and the corresponding side wall of the trough. Mixing bucket according to claim 8, characterized in that the anchoring and articulation points of the connecting rod (39) which holds the flap (27), are arranged in such a way that they cause clearance almost complete opening when the flap (26) is operated by the jack (30), which flaps (26, 27) are found in a folded position, one on the other, in the extension of the front wall (42) of the trough. Mixing bucket according to claim 9, characterized in that the connecting rod (39) is articulated on the side wall (2) of the trough, at a point which located substantially mid-length of the front flap (26) when the latter is in the closed position, and in that it is articulated on the flap (27), in a point located approximately 1/3 of the length of this flap, length taken at from the articulation interposed between the two flaps (26, 27).

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