Planetary mixer

Abstract: A planetary mixer having blades which conduct a planetary motion within a tank. A head vertically movably provided above the tank has a drive shaft extending downwardly. The drive shaft has a rotary body, which is provided with three driven shafts at positions corresponding to the respective apexes of an equilateral triangle. The blade is provided at the leading end of each driven shaft. When the rotary body is rotated by the drive shaft, a planetary gearing causes the three blades to rotate on the respective axes of the driven shafts and to simultaneously revolve them around the drive shaft, so that they conduct the planetary motion.

Description: The invention relates to a planetary mixer for kneading materials to be processed by means of blades which conduct a planetary motion. DE-A-2 440 809 discloses a mixer for kneading materials having three shafts being fitted to a rotary body, wherein each driven shaft carries one blade. This mixer is designed to knead very sensible material. Thus the shearing forces in the material have to be maintained on a low level. Therefore, the blades are idling free on the shafts, and rotation around each shaft is only caused by the material itself, when the rotary body is rotated together with the driven shafts. For limiting the shearing forces, each blade should not have a diameter greater than the distance between the shafts of the blades and the shaft of the rotary body. The blades don't interfere with one another. If such a mixer would be used to knead highly viscous material, the whole material in a tank would be rotated as a columnarily collected unit without any kneading efficiency. EP-A 0 350 665 discloses a mixer having three blades driven by a planetary gear. Thus the blades are arranged in a row. Therefore, certain ratios between rotational speed of each blade have to be adjusted. The blades are running at different rotational speeds causing different loads acting on the blades, which results in blades vibration and other defects. The material is not homogenously kneaded, as the material is columnarily collected. An object of the present invention is to provide a planetary mixer designed-to make blades do equal work simultaneously to suppress the generation of a variable load and capable of uniformly mixing and agitating materials without allowing them to columnarily collect together. Another object of the present invention is to provide a planetary mixer capable of eliminating a dead space in a tank while blades are moving in the tank and of dispersing and kneading materials efficiently by applying a shearing force to them between the blade and the inner wall of the tank and also between the blades in the central part of the tank. The foregoing objects of the present invention are accomplished by the features in the claim. These objects, and features will become more apparent with reference to the accompanying drawings in which: Fig. 1 is an elevational view of a planetary mixer embodying the present invention, illustrating a cover and a tank in section. Fig. 2 is an enlarged sectional view of the drive shaft portion. Fig. 3 is a diagram of the blades embodying the present invention, illustrating the relation between the blades and the tank. Referring first to Fig. 1 as an elevational view of a planetary mixer according to the present invention, a body 1 accommodates a detachable tank 2, and an agitating head 3 formed on the tank. The head 3 is guided by a guide rod 4 and vertically moved by a hydraulic cylinder 5. The head 3 may vertically be moved by two hydraulic cylinders provided in the form of a gate. The head is also fitted with a motor 7 for rotating a drive shaft 6. The transmission mechanism between the motor and the drive shaft may be arranged in various ways, an example of which is, as shown in Fig. 1, to use a chain 10 for connecting a drive sprocket 8 formed on the motor shaft with a driven sprocket 9 on the drive shaft. As shown in Fig. 2, the drive shaft 6 is passed through a support cylinder 11 fixed to the head 3, the upper and lower portions being rotatably supported by bearings 12, 13, respectively. A rotary body 14 is fixed with a key 15 at the trailing end of the drive shaft 6. The peripheral edge of the rotary body, which is cylindrical in configuration, is extended upward and screwed in a rotatable cover plate 16 that is put on the support cylinder 11. Three driven shafts 17, 17, 17 are pivotally fitted to the rotary body 14 in such a way as to surround the drive shaft 6. In terms of an elevational view, the driven shafts are disposed so that they are positioned at their respective apexes of an imaginary equilateral triangle (Fig. 3). The driven shafts are rotatably Supported with bearings 18, 19, respectively. A planetary gear 20 is fixed with a key 21 to the leading end of each driven shaft 17 and engaged with a sun gear supported by the support cylinder 11. Although an internal sun gear 22 secured to the support cylinder 11 in such a way as to surround the planetary gear is employed as the sun gear stated above in Fig. 2, such a sun gear may be placed, if desired, in the center of the planetary gear in the leading portion of the support cylinder (not shown). A blade 23 is fixed with a key 24 to the trailing end of each driven shaft 17 to make it move in close proximity to the inner wall of the tank. The blade may be a frame-type one or of any other construction. Incidentally, the blade shown in Fig. 1 is formed by 90-degree twisting the lower side of a square frame piece, so that materials are forced down against the bottom of the tank 2. The outer periphery of the rotary body is enclosed with a cover 25. When materials are put into the tank 2 with the head 3 lowered, each blade 23 rotates on the axis of the driven shaft and simultaneously revolves around the drive shaft, i.e., it conducts a planetary motion. With the use of the internal sun gear at that time as shown in Fig. 2, the direction of its revolution is rendered opposite to that of rotation. As the blades conduct the planetary motion in close proximity to the inner wall of the tank, a strong shearing force is applied to the materials between the blade and the wall of the tank and between the blades. As a result, the materials can satisfactorily be dispersed, agitated, kneaded and the like. Since the three blades operate likewise, the three driven shafts bear an equal load and this makes it possible to use the mixer without the worry of causing a variable load. In addition, the materials are prevented from columnarly collecting together. Fig. 3 illustrates the embodiment of the present invention. As shown in Fig. 3, the breadth of the blades is arranged so that the ends of the blades overlap each other when the blades conduct the planetary motion. In other words, the breadth (the distance between the end edges) of the blade is made longer than the distance between the axes (ab), (bc), (ac) of the driven shafts. Moreover, the radius (covering the length from the axis of the blade shaft up to the end edge thereof) of a blade 26 rotating in close proximity to the inner wall of the tank is set slightly shorter than the distance from the shaft position (a), (b), (c) up to the inner wall of the tank. While the end of one blade 26 is directed to the center as shown in Fig. 4, the ends of the remaining two blades 26, 26 are arranged at a position close to the intersection of their rotary loci, whereby these blades are caused to overlap each other within the range of intersection of their rotary loci, when they are turned in direction of arrows. In this arrangement, as the blades conduct the planetary motion in close proximity to the inner wall of the tank together with their end edges overlapped, a strong shearing force is applied to the materials between the blade and the inner wall of the tank and between the blades. As a result, the materials can satisfactorily be dispersed, agitated, kneaded and the like. Since the three blades overlappingly conduct a motion, moreover, a dead space is practically prevented from being produced in the tank. Therefore, the materials are efficiently processable and besides prevented from columnarly collecting together.

Claims: Planetary mixer for kneading materials to be processed by means of blades (26) conducting a planetary motion in a tank (2) comprising three driven shafts (17) being fitted to a rotary body (14) at the trailing end of a drive shaft (6) so as to surround said drive shaft (6), each driven shaft (17) carrying one blade (26), wherein the driven shafts (17) are arranged at positions corresponding to respective apexes of an imaginary equilateral triangle surrounding the drive shaft (6), which drives a planetary gear (20) at the top of each driven shaft (17), and wherein the blades are designed so that in a position during use the leading end of one blade (26) is in close proximity to the inner wall of the tank (2), while the other leading end of the blade extends to the center of the tank (2), and that the ends of the remaining two blades (26) are arranged at a position close to the intersection of their rotary loci, whereby these blades (26) are caused to overlap each other within the range of intersection of their rotary loci.

Inventors: INOUE MASAKAZU C O INOUE SEISA, INOUE, MASAKAZU, C/O INOUE SEISAKUSHO (MFG) CO.LTD
Applicants: INOUE MFG, INOUE SEISAKUSHO (MFG) CO., LTD.
Application year: 1991
Main classification: B01F7
IPC codes: B01F7