Machine for fractionating and / or separating grain products

Abstract

The invention relates to a machine (1) for fractionating and / or separating grain products, which is designed to cause at least one screen stack (2, 3) of screen frames (4) each comprising one screen to oscillate. The machine has a platform (11, 14) on which the screen stack can be placed. The machine also has, above the platform (11, 14), a clamping element (for example a clamping frame; 15, 11), wherein the screen stack can be clamped between the platform and the clamping element in order to press the screen frames (4) of the screen stack against one another and thus fix them in relation to the platform and the clamping element. The machine is characterized by a mechanical operating element that can be operated by hand, and by a transmission mechanism which converts a movement of the mechanical operating element into a vertical relative movement of the clamping element in relation to the platform. Due to this vertical relative movement, the clamping element (15) is movable in relation to the platform between a clamping position and an open position.

Description

[0001] FRACTIONING AND / OR SEPARATION MACHINE

[0002] OF CEREAL PRODUCTS

[0003] The invention relates to a machine for fractionating and / or separating grain products, for example a plansifter.

[0004] Machines for fractionating and / or separating grain products are used, on the one hand, to separate the components of a ground product into coarser and finer grained components and, depending on the case, also components of different densities and / or to remove foreign matter from the ground product. On the other hand, grain cleaning machines are well-known examples of such machines. In these machines, the unground grain is separated from unwanted components that were harvested along with the grain. The separation of the ground product into components of different grain sizes is also referred to as "classifying" or "fractionating". Plan sifters are generally used in grain mills to fractionate the ground grain products between and after passes through the roller mill of a grain mill. They can also be used for so-called control sifting, i.e. the sieving of flour that is otherwise ready for sale.Plan sifters and certain types of grain cleaning machines feature stacks of sieve frames, each with a sieve acting as a plan screen. These stacks are set into horizontally oscillating movements by a drive mechanism, particularly circular oscillations in the sieve plane. This subject them to relatively high accelerations.

[0005] Often, especially in larger plansifters, the screens are arranged in a housing that houses a number of screens forming a so-called screen compartment. The screen frames are clamped together by mounting a door on the front of the screen compartment and pressing a clamping frame with a spindle drive—or possibly by spring force—down onto the screen stack from above.

[0006] Open plansifters without a screen housing have also been proposed. The screen stacks of open plansifters are mounted on a support frame and clamped downwards with clamps and nuts via a clamping frame. For additional lateral support, the stacks can be guided laterally by parts of the support frame and the clamping frame.

[0007] What plansifters with housings and plansifters with open sieve compartments have in common is that replacing sieve frames is relatively complex. In plansifters with housings, the door must be removed and the clamping frame moved upwards, whereupon the sieve frames above the sieve frame to be replaced, which are already relatively difficult to access, have to be moved forwards in order to access the sieve frame to be replaced. In plansifters with open sieve stacks, the nuts must be removed individually using suitable tools or at least lifted so that the clamping frame can be lifted and removed. DE 10 2010 017826 A1 discloses a screening machine, e.g. a tumbler screening machine or vibrating screening machine, for the food industry, among other things. The screening machine has a clamping device with which an uppermost sieve insert or a hood can be clamped against a pan below. This is done tool-free using a so-called toggle lever.In DE 10 2010 017826 A1, a 'knee lever' is defined as a lever element with a handle. In the true sense of the definition of a toggle lever, this lever element forms a toggle lever together with another lever element, namely a rod.

[0008] DE 2011 115367 B3 discloses a tumbler screening machine. A tensioning system is formed by individual hydraulic or pneumatic cylinders, which enable tensioning or lifting of the elements of the screening structure by synchronously moving rods (lifting rods).

[0009] DE 39 37 176 A1 shows a plansifter with a system that allows the sieves of a stack to be either clamped or lifted. The D3 is characterized by several pairs of so-called sieve frame ladders, which, when the tension is released, allow the sieve frames to be placed one after the other on lateral rails (support bars), allowing any desired sieve frame to be removed.

[0010] DE 1 203 102 discloses a so-called tapping device. The test sieves are clamped in place using a rod.

[0011] US 4,233,151 relates to a device for sorting wood chips with a stack of vibrating screens. The screens are clamped together using a type of toggle lever. It is an object of the present invention to create a machine for fractionating and / or separating grain products that overcomes disadvantages of the prior art and makes changing screen frames more user-friendly.

[0012] This object is achieved by a machine for fractionating and / or separating grain products, which is configured to set at least one sieve stack of sieve frames, each with a sieve, in oscillating movements. The machine has a platform on which the sieve stack can be placed, and the machine further has a clamping element (e.g. a clamping frame) above the platform. The sieve stack can be clamped between the platform and the clamping element in order to press the sieve frames of the sieve stack against one another and thus fix them relative to the platform and the clamping element. The machine is characterized by a manually operated mechanical control element and a transmission mechanism which converts a movement of the mechanical control element into a vertical relative movement of the clamping frame relative to the platform.

[0013] By definition, a transmission mechanism is understood to be a mechanism in the technical sense, i.e. a coupling of the components of the mechanism which is designed in such a way that each movement of one element causes a movement of other elements of the mechanism. In this way, a transmission mechanism differs particularly from devices in which an operating element (e.g. a touch screen or a push button or slider) is read electronically, and a drive with its own energy source - e.g. an electric, hydraulic or pneumatic drive - triggers the desired movement in response to a movement of the operating element. Because the transmission mechanism converts the movement of the mechanical operating element into the vertical relative movement, the drive for the vertical relative movement is provided by the operation of the mechanical operating element, i.e. the drive is mainly powered by muscle power.A separate power source, especially pneumatic or similar, is not necessary. The transmission mechanism can be purely mechanical.

[0014] The vertical relative movement allows the clamping frame to be moved relative to the platform between a clamping position and an open position.

[0015] Such a vertical relative movement may include a vertical movement of the platform and / or the clamping frame relative to the floor on which the machine is parked, ie it is possible that the clamping frame is moved upwards and / or that the platform is moved downwards when moving from the clamping position to the open position - and vice versa.

[0016] In the open position, screen frames can be easily removed and reinserted or replaced. Unlike with the current state of the art, an operator only needs to move the control element—e.g., a lever—to remove the screen frames.

[0017] The machine, in particular, comprises a frame that is suspended during operation (i.e., provided with fastening structures for a suspension device). The transmission mechanism can, for example, comprise a deflection mechanism that is housed in the frame or attached to it, along with a linkage—e.g., comprising a plurality of clamping rods—that is set into vertical movement by the deflection mechanism when the mechanical control element is actuated.

[0018] The transmission mechanism can, in particular, be designed such that a plurality of clamping rods are moved synchronously in the same direction to move the clamping element upwards or the platform downwards. The movement of the single mechanical control element is thus converted, in particular, into the synchronous vertical movement of several clamping rods (the term "rods" here also includes, for example, hollow rods, i.e., sufficiently mechanically stable tubes, or elements of other shapes that can mechanically function as a rod).

[0019] For example, the rod assembly can have four clamping rods that are moved synchronously and in the same direction during the vertical relative movement.

[0020] Such a deflection mechanism can also be located somewhere other than on or in the frame. In some embodiments, it is stationary, particularly in the sense that it is not subject to any vertical movement relative to the frame when the movement occurs between the open position and the clamping position.

[0021] In a special group of embodiments, the frame is arranged approximately centrally (with respect to the vertical), with an upper sieve stack resting on the frame and a lower sieve stack resting on a support frame below the frame. The frame then forms the clamping element for the lower sieve stack, and the support frame forms the platform for the lower sieve stack and is vertically movable by the transmission mechanism. On the other hand, the frame serves as a platform for the upper sieve stack, as the stack rests thereon. A clamping frame serves as the clamping element for the upper sieve stack and is movable by the mechanism in the vertical direction opposite to the movement of the support frame. During movement into the open position, the support frame is lowered and the clamping frame is raised simultaneously, and vice versa during movement into the clamping position.

[0022] Accordingly, the linkage may comprise a first group of clamping rods - e.g., four upper clamping rods - which are moved synchronously in a first direction by the transmission mechanism to move the clamping frame, and a second group of clamping rods - e.g., four lower clamping rods - which are moved by the transmission mechanism synchronously with the first group of clamping rods and synchronously with each other in the direction opposite to the first direction to move the support frame.

[0023] However, it is also possible to have two stacks that are not vertically stacked. Instead, according to a first option, a frame can be suspended in such a way that it serves as a platform, and a clamping frame above the stack of screens resting on it serves as the clamping element. According to a second option, conversely, a suspended frame can serve as the clamping element, and a support frame that can be lowered relative to it by the transmission mechanism serves as the platform.

[0024] The transmission mechanism is particularly designed such that a dead center is defined, and upon movement into the clamping position, the mechanical operating element is moved toward the dead center and slightly beyond the dead center to a first stop, thus locking the clamping frame relative to the platform in the clamping position. Such a self-locking design is particularly advantageous because it locks the clamping device by operating the operating element itself: the operator can move the clamping device into the clamping position and reliably lock it in place with a single movement.

[0025] The first stop does not have to be formed by the operating element itself (i.e., the operating element itself does not have to be physically located somewhere), but can also be formed inside the deflection mechanism or elsewhere; the first stop simply means that the relative movement generated by the operating element in the direction towards the clamping position is mechanically limited.

[0026] The transmission mechanism can, in particular, include a toggle lever mechanism. This has the additional advantage that, due to its design, the force transmission ratio is particularly high near the dead center, which inevitably allows the clamping force to be relatively high (i.e., the screen frames of the screens can be pressed tightly against one another, even in a stack with a large number of screen frames), without the operator having to exert excessive force.

[0027] Such a toggle lever mechanism can, in particular, comprise two lever elements that act together in the manner of a toggle lever, with one of the lever elements being connected to the linkage—in particular to a clamping rod—that attaches to the clamping element or platform and is moved vertically by the toggle lever. The other lever element of the toggle lever is typically pivotable about a fixed (frame-fixed) attachment point, with such pivoting movement being triggered by the movement of the mechanical operating element. This design allows the clamping rod to be moved linearly and vertically and is not subject to a pivoting movement, as would be the case if the clamping rod itself were part of a toggle lever.

[0028] As an alternative to the toggle lever mechanism, a cam disc can also be used, the control curve of which defines the dead center.

[0029] A second stop can be defined toward the open position to limit the relative movement. The open position can then be reached at the location of the second stop.

[0030] If the transmission mechanism has a toggle lever, a first lever element of the toggle lever can be formed by a lever wheel, or it can be driven by a lever wheel (the latter means that the rotation of the lever wheel can cause a pivoting movement of the - then separate - first lever element of the toggle lever around a fixed starting point, e.g., corresponding to the axis of the lever wheel). A second lever element of the toggle lever is, on the one hand, articulated to the first lever element to form the toggle lever and, on the other hand, articulated to the linkage - e.g., the clamping rod. The linkage is guided in such a way that only vertical movement is possible. Thus, a rotation of the lever wheel causes the desired vertical relative movement.

[0031] To drive the lever wheel, an operating wheel can be provided that is directly or indirectly connected to the mechanical operating element—e.g., the operating lever. Since, in embodiments, two clamping rods on either side of a screen stack are moved synchronously and in the same direction, two operating wheels can be provided on each side of the screen stack, which are coupled—e.g., via a deflection wheel—so that they run synchronously. If, as described above, the transmission mechanism causes the simultaneous movement of an upper and a lower rod in opposite directions, separate lever wheels can be provided for the upper rod and the lower rod, which are driven, for example, by the same operating wheel.

[0032] The linkage can have a clamping rod where it is connected to the toggle lever—regardless of the possible presence or absence of rods moving in opposite directions—which is guided on both sides. This means that the toggle lever is arranged not only along one side of the clamping rod, but along two opposite sides. For example, two lever discs can be present, which form the second lever element of the toggle lever and which are parallel to each other on opposite sides of the clamping rod. A pin is then guided through the clamping rod (through a horizontal hole) and articulated to one of the lever discs on each side.

[0033] This double-sided guide has the advantage that jamming is reliably prevented even when substantial forces are applied, e.g. when moving beyond the dead center, since no torque can be coupled into the lever rod.

[0034] The double-sided guide can also mean that the other elements of the deflection mechanism are present in duplicate and on both sides of the lever rod, i.e., if applicable, the operating wheel(s), the lever wheel(s), if applicable, the deflection wheel, etc. In one group of embodiments, the machine has a device which causes the targeted raising or lowering of only a portion of the screen stack by moving the mechanical operating element. Such a device can be selectively engaged by a user with one of the screen frames of the screen stack (the 'dedicated' screen frame) in order to raise this screen frame together with all the screen frames above it during a movement from the clamping position to the open position, or to prevent this screen frame together with all the screen frames above it from participating in a lowering movement.This allows the removal—and, if necessary, replacement—of the screen frame directly below the dedicated screen frame when the device is in the open position. Unlike the prior art, this can be done without having to remove all the screen frames located above the one to be removed. This represents a substantial advantage, as it significantly reduces both the operator's workload and downtime.

[0035] If the vertical relative movement of the clamping element relative to the platform involves an upward movement of the clamping element relative to the frame, then the device can be attachable to the clamping rods that run between the frame and the clamping element. When these clamping rods move upward relative to the housing, the device then follows this movement and lifts the dedicated screen frame and the screen frames above it along with the clamping element.

[0036] If the vertical relative movement of the clamping element relative to the platform involves a downward movement of the platform relative to the frame, the machine can have fastening elements that remain stationary during the vertical relative movement relative to the frame and are suitable for securing the device. Such fastening elements can, for example, comprise tubes that surround the clamping rods leading downward from the frame (possibly the lower clamping rods). Alternatively, they can also be fastening rods running parallel to these clamping rods, which, unlike the clamping rods, are fixed to the frame and do not move vertically when the operating element is moved.

[0037] In both cases, the device can have a plurality of tabs, each of which can be attached at a selectable position to one of the clamping rods or one of the fastening elements. The tabs or an element attachable to the tabs - e.g., a connecting element between two tabs - engage underneath the dedicated screen frame. The attachment can be made, for example, such that the respective tab is clamped to the clamping rod or fastening element when the dedicated screen frame is pressed downwards relative to the clamping rod or fastening element due to its weight (and, if applicable, the weight of the screen frames resting on it). Such a simple construction can ensure that the tabs remain stable relative to the clamping rod or fastening element under weight load, regardless of the weight of the screen frames.

[0038] In both cases, it may be advantageous if the elements (clamping rods; fastening elements) to which the device - e.g. the riders of the device - can be fixed have a constant cross-section (i.e. the cross-section is not dependent on the axial, i.e. vertical position) and / or if structures for fixing the device are present at regular intervals corresponding to the vertical extension of the screen frames.

[0039] Embodiments of the invention are described below with reference to drawings. In the drawings, like reference numerals denote like or analogous elements. The drawings partially show corresponding

[0040] Elements vary in size from figure to figure. Shown are:

[0041] Fig. 1 : a view of a plansifter with an upper sieve stack and a lower sieve stack;

[0042] Fig. 2 is a view of the plansifter according to Fig. 1, in the open position;

[0043] Fig. 3 is a view of the deflection mechanism, with elements of the deflection mechanism located at the front from the viewer's perspective being drawn in an exploded view;

[0044] Fig. 4 is a sectional view of the deflection mechanism in the clamping position, corresponding to Fig. 1;

[0045] Fig. 5 is a sectional view corresponding to Fig. 4 in the open position;

[0046] Fig. 6 is a partial view of the elements shown in Fig. 4 with an illustration of the toggle lever principle and the self-locking mechanism;

[0047] Fig. 7 is a schematic representation of a plansifter with devices for selectively raising or lowering a part of the sieve stack; and

[0048] Fig. 8 shows the plansifter from Fig. 7 in the open position.

[0049] Figure 1 shows a plansifter 1 with a single pair of sieve stacks with an upper sieve stack 2 and a lower sieve stack 3. In the illustrated embodiment, the plansifter is an open plansifter in which the sieve frames 4 with the sieves (not visible in Fig. 1, but designed, for example, as described in Swiss patent application 1319 / 2022) are present without a housing surrounding the sieve stacks. In the illustrated embodiment, the frame 11 is for the sieve stacks, which serves as a second platform and as a second clamping element. The frame 11 is arranged centrally in the sense that the upper sieve stack 2 rests on the frame 11 and the lower sieve stack is suspended from it, i.e. it is arranged below the frame 11.As known from Swiss patent application 722 / 2022, the frame 11 also supports a drive module with a flywheel, so that the drive is also centrally located and the plansifter is suitable for a modular design. Such a modular design means that a required number of units consisting of an upper screen stack, a lower screen stack, and drives can be arranged side by side, for example, forming one or more rows. In such a case, compared to the embodiment of Fig. 1, only the frame 11 needs to be modified accordingly and configured to accommodate several pairs of screen stacks, as also shown in 722 / 2022.

[0050] The frame 11 has fastening structures 12 in order to suspend the entire plansifter 1 by means of a suspension device, for example with suspension rods 13.

[0051] The screen frames of the upper screen stack 2 rest on the frame and / or an element attached thereto—e.g., the drive module. The screen frames of the lower screen stack rest on a support frame 14, which is suspended from the frame via lower clamping rods 24, described in more detail below. The support frame 14 also serves as a screenings outlet, having outlets 7 on the underside for attachable outlet lines.

[0052] On top of the upper screen stack 2 there is a clamping frame 15 which also serves as an inlet frame. This frame has at least one top inlet 6 to which an inlet line can be attached and through which the screened material can be fed. The clamping system has an operating lever with an operating lever rod 21 and an operating lever arm 22 on each side (in relation to the lower and upper operating stacks). By manual actuation - when the plansifter is at a standstill - the operating lever can be pivoted upwards from the position shown in Fig. 1 to the position shown in Fig. 2. This causes two upper clamping rods 23 on each side (three of the four upper clamping rods are hidden in Fig. 1 and Fig. 2) to be moved upwards. The clamping frame 15 attached to it is thereby raised. At the same time, the two lower clamping rods 24 on each side are moved downwards.This lowers the support frame 14 with the lower sieve stack 3 resting on it. In this configuration, as shown in Fig. 2, frames can be removed from the upper sieve stack and / or the lower sieve stack and reinserted or replaced, for example, after replacing the sieve or cleaning, etc.

[0053] The deflection mechanism 8 of the transmission mechanism, which converts the movement of the operating lever into the vertical movement of the upper and lower clamping rods, is attached to the inside of the frame 11 on both sides.

[0054] In embodiments with more than one pair of sieve stacks, each with an upper and lower sieve stack, each pair of sieve stacks can have its own transmission mechanism. It would also be possible to combine groups of sieve stack pairs, or even all sieve stack pairs, and provide them with a common transmission mechanism.

[0055] The transmission mechanism is explained below with reference to Figures 3-6. The lever arm 22 is directly connected to a first operating wheel 31, which is rotated about the pivot axis of the operating lever (operating lever axis 30) by the pivoting movement of the lever arm 22. In the illustrated embodiment, the first operating wheel 31, as well as a second operating wheel 32 rotatable about an operating wheel axis 38, each have an operating wheel disc with curved elongated holes 39 (described below) and an external toothing 34 along at least part of its circumferential line, as well as an operating wheel ring with internal toothing 43 fastened thereto. In the illustrated embodiment, the operating wheel disc of the first operating wheel 31 is integral with the lever arm 22 and is formed by a portion of the lever arm 22.

[0056] The rotational movement of the first operating wheel 31 caused by the pivoting movement of the lever arm 22 is transmitted via the external toothing 34, a deflection wheel 33, and the external toothing 34 of the second operating wheel 32 to the second operating wheel 32, which has the same outer diameter as the first operating wheel 31 and therefore rotates synchronously with the first operating wheel 31. The internal toothings 43 of the first and second operating wheels each cause a rotation of two lever wheels 35, each designed as gears, which are arranged within the operating wheel ring.

[0057] A lever disc 36 is attached to each lever wheel via a first pin 45, which in turn is connected to the upper or lower clamping rod 23; 24 via a second pin 47. The upper or lower clamping rod 23, 24 is guided in a first guide tube 41 or second guide tube 42 and can therefore only be moved vertically. The rotation of the lever wheels 35 caused by the rotation of the first and second operating wheels 31, 32 therefore causes the upper and lower clamping rods to be moved upwards or downwards via the lever discs 36, as shown in Figures 1 and 2. Since the two operating wheels rotate synchronously, the front and rear (in relation to the view from where the operator is standing, i.e. the right and left in the figures) upper and lower clamping rods are also moved synchronously. Since the structure according to Fig.3, with deflection mechanism and housing as well as clamping rods, on both sides of the sieve stack (again in relation to the view from where the operator is standing, ie in front of and behind the sieve stacks in the figures) mirrored to each other, a total of four upper clamping rods 23 and four lower clamping rods 24 are moved synchronously when the operating lever is actuated in order to move the support frame 14 and the clamping frame 15 vertically in a stable orientation.

[0058] As can be seen particularly well in Fig. 6, the lever wheels 35, together with the lever disks 36, each form a toggle lever. In Fig. 6, the first connection 51 between the stationary axis of rotation 37 of the lever wheel 35, on the one hand, and the lever joint - corresponding to the axis of the first pin 45 - on the other hand, is shown in dashed lines. The second connection 52 between the lever joint, on the one hand, and the second pin 47 - whose position can only be moved vertically - is also shown, but with a different dashed line. Fig. 6 shows the situation in which the clamping frame 15 and the support frame 14 are in the clamping position and the operating lever is pivoted downwards, i.e. in the position according to Fig. 1. It can be seen that at the end of the movement from the open position to this clamping position (in Fig.6 by the block arrow) the toggle lever is overextended beyond the dead center (at which the first connection 51 and the second connection 52 are collinear) until it touches the stop, which in the illustrated embodiment is formed by the lever discs 36 touching the axes 37 of the lever wheels 35; other mechanical stops would be conceivable. The axes 37 of the lever wheels 35 are also the reason for the curved shape of the lever discs 36. By overextending the toggle lever (lever wheel 35 with lever disc 36) and touching the stop, the clamping system is locked in the clamping position. The weight of the lower screen stack 3, which rests on the support frame 14, as well as the counterforce of the screen stack to the clamping force (due to an always present elasticity) prevent the lock from opening.This is achieved by first moving the toggle lever back past the dead center against these forces in order to be moved away from the clamping position. During this movement back past the dead center, the second pins 47 of the lower clamping rods 24, and thus the lower clamping rods with the support frame, are moved slightly upwards, and the second pins 47 of the upper clamping rods 23, and thus the upper clamping rods 23 with the clamping frame, are moved slightly downwards, counter to the counterforce to the clamping force, before the clamping force is released after the movement past the dead center (opposite the direction of the block arrow in Fig. 6), which requires active actuation / unlocking.

[0059] In the embodiment shown in Figures 1-6, the movement into the open position is supported by the weight of the lower sieve stack, whereas the movement into the clamping position occurs against this weight and therefore requires a certain amount of force. It is also possible to adjust the force required for the movements using separate means, e.g., a spring device. This may be of particular interest—but not exclusively—in embodiments in which the relative movement of the clamping frame and the platform does not involve any movement of the platform (i.e., when only the clamping frame is moved upwards during the transition to the open position).

[0060] In particular, Fig. 3 shows an optional feature of the illustrated embodiment: the upper and lower clamping rods are each guided on both sides. The first operating wheel 31, the second operating wheel 32, the deflection wheel 33, the lever wheels 35, and the lever discs 36 are each located on both sides of the upper clamping rods 23 and both sides of the lower clamping rods 24 - i.e., in Fig. 3, in front of the upper and lower clamping rods and behind the upper and lower clamping rods. The axes of the operating wheels 31, 32, the deflection wheels 33, and the lever wheels 35 each connect the front wheel with the corresponding rear wheel, i.e., they are common to the respective front and rear wheels. The lever arm 22 of the operating lever is also made up of two parts, as illustrated in Fig. 6 (in Fig.6, the elements located in front of the upper and lower clamping rods are drawn separately, while the corresponding elements located behind them are illustrated in the assembled state so that their interaction can be seen.

[0061] The elongated holes 39 in the first and second operating wheels are provided so that the outwardly projecting axle stubs of the axles 37 of the lever wheels 35 and the respective operating wheels do not get in each other's way.

[0062] Also shown in Fig. 3 is that the illustrated embodiment includes a housing having a cover plate 21 on each side, which accommodates the deflection mechanism 8, i.e., the operating wheels 31, 32, deflection wheels 33, lever wheels 35, and guide tubes 41, 42. The housing is at least partially open at the bottom for the lever arm 22.

[0063] Figure 7 shows a schematic of a plansifter 1 which is constructed similarly to that of Fig. 1, with a single pair of sieve stacks with an upper sieve stack 2 and a lower sieve stack 3. The plansifter 1 is characterized by a device for the targeted lifting of a part of the upper sieve stack 2 and a device for the targeted lowering of a part of the lower sieve stack 3. The first device (device for the targeted lifting of a part of the upper sieve stack 2) has a rider 61 for each upper clamping rod 23, which can be attached relative to the clamping rod 23 at a location that can be selected in relation to the vertical. Each rider 61 is designed in such a way that it is fastened to the clamping rod 23, at least when a weight force presses it downwards relative to the clamping rod 23, and thus follows the upward movement of the upper clamping rod 23 during the movement from the clamping position (Fig. 7) to the open position (Fig. 8), as shown in Fig.8 is indicated by arrows. The tabs 61 or a connecting element 67 attached to them engage with the dedicated clamping frame 65 (depending on the selected vertical position of the tabs and, if applicable, the connecting element), for example, by a structure of the tabs or the connecting element engaging under this clamping frame or a structure of the clamping frame. Thus, the dedicated clamping frame 65 is raised with the tabs 61 and, if applicable, the connecting element 67.

[0064] On the side opposite the illustrated side of the plansifter 1 (i.e., at the rear with respect to the illustration in Figs. 7 and 8), the device can have identically designed elements (tab 61, optionally connecting element 67) which are to be placed at the same vertical position.

[0065] The second device (device for the targeted lowering of a portion of the lower screen stack 3) is designed analogously to the first device and can be identical to it. (In practice, unlike what is illustrated in Fig. 7 and Fig. 8, only a single such device can be present, which can be used either as the first device or as the second device.) It therefore also has tabs 61 and optionally a connecting element 67. In contrast to the first device, it is not attached to the respective (lower) clamping rod 24, but rather to fastening elements 64 provided for this purpose, which are shown here as tubes that surround the lower clamping rods 24 at least in an upper area. When the support frame 14 is lowered, the second device prevents the dedicated screen frame 65 and the screen frames resting on it from being lowered, which is also illustrated by arrows in Fig. 8.

[0066] The optional connecting elements 67 can, on the one hand, comprise structures that interact with the situation-dependently selected screen frame (the dedicated screen frame) to prevent it from being raised or lowered. Regardless of whether this is the case or not, they have the function of enabling the simultaneous movement of the two tabs 61 with a single handle. In particular, they can be designed such that operation (placing in the selected position for engagement with the dedicated screen frame) is possible from the handle side, i.e., from the left in Fig. 7 and Fig. 8. Operation is then also possible when several screen stacks are arranged side by side.

[0067] In the open position according to Fig. 8, the sieve frame below the dedicated sieve frame in the upper sieve stack and in the lower sieve stack can be easily removed and replaced if necessary.

[0068] The invention would also be feasible if there were no division between the upper sieve stack and the lower sieve stack and accordingly no second platform, and the transmission mechanism would, for example, only lower the support frame or only raise the clamping frame.

[0069] The invention could also be used for plansifters with closed sieve boxes, in which case, for example, the bottom or the lid could be raised or lowered to release the clamping force between the sieve frames within the sieve box so that the sieve frames can be removed.

Claims

PATENT CLAIMS 1. Machine (1) for fractionating and / or separating grain products, which is designed to set at least one sieve stack (2, 3) of sieve frames (4), each with a sieve, in oscillating movements, wherein the machine has a platform (14; 11) on which the sieve stack (2; 3) can be placed, and wherein the machine further has a clamping element (11; 15) above the platform (14; 11), wherein the sieve stack can be clamped between the platform (14; 11) and the clamping element (11; 15) in order to press the sieve frames of the sieve stack (2; 3) against one another and thus fix them relative to the platform and the clamping element, characterized by a manually operable mechanical operating element and a transmission mechanism which converts a movement of the mechanical operating element into a vertical relative movement of the clamping element relative to the platform.

2. Machine according to claim 1, comprising a frame (11) with fastening structures (12) for a suspension device.

3. Machine according to claim 1 or 2, wherein the transmission mechanism comprises a deflection mechanism (8) and a linkage, wherein the deflection mechanism is arranged to set the linkage into a vertical movement when the mechanical operating element is actuated, which causes the vertical relative movement.

4. Machine according to claim 3, the deflection mechanism is arranged to move several clamping positions of the rod synchronously in the same and / or in an opposite direction.

5. Machine according to claim 4, wherein the linkage comprises four clamping rods (23; 24) which are moved synchronously and in the same direction during the vertical relative movement.

6. Machine according to one of claims 3 to 5, wherein the linkage comprises a first group of clamping rods which are moved synchronously in a first direction by the transmission mechanism upon movement of the operating element, and a second group of clamping rods which are moved by the transmission mechanism synchronously with the first group of clamping rods and synchronously with one another in a direction opposite to the first direction.

7. Machine according to one of claims 3 to 6, comprising the frame (11), wherein the deflection mechanism is present on the frame (11) or in the frame (11) and 8. Machine according to one of claims 3 to 7, comprising a lower support frame (14) below the frame (11) and a clamping frame (15) above the frame (11), wherein the transmission mechanism is designed to move the support frame (14) and the clamping frame (15) vertically in opposite directions upon actuation of the mechanical operating element, whereby the support frame (14) forms the platform for a lower sieve stack (3) and the frame (11) forms the platform for an upper sieve stack (2), and the frame (11) forms the clamping element for the lower sieve stack (3) and the clamping frame (15) forms the clamping element for the upper sieve stack (2).

9. Machine according to one of the preceding claims, wherein the transmission mechanism is designed so that a dead center is defined, and that during a movement into the clamping position, the mechanical operating element is moved towards the dead center and beyond the dead center to a first stop, so that the clamping frame is locked relative to the platform in the clamping position.

10. The machine according to claim 9, wherein the transmission mechanism comprises a toggle lever, wherein the dead center is a dead center of the toggle lever.

11. Machine according to claim 10, wherein the toggle lever has two lever elements (35, 36) which together act as a toggle lever, wherein one of the lever elements (35) is pivotable about a fixed attachment point and the other of the lever elements (36) is connected to the linkage which is attached to the clamping element or the platform and is vertically movable by the toggle lever.

12. Machine according to claim 10 or 11, wherein the movement of the mechanical operating element generates a rotary movement of a lever wheel (35) which forms or drives a first lever element of the toggle lever, wherein a second lever element (36) of the toggle lever is connected on the one hand to the first lever element and on the other hand in an articulated manner to the linkage in order to effect the vertical relative movement.

13. Machine according to one of claims 10 to 12, wherein the linkage has a clamping rod (23, 24) which is guided on both sides.

14. Machine according to claim 13, wherein a pin (47) is guided through the clamping rod and is articulated on both sides with a lever disc (36) which lever disc (36) forms the second lever element of the toggle lever.

15. Machine according to one of the preceding claims, comprising a device which is designed to effect a targeted raising or lowering of only a part of the sieve stack (2; 3) when the mechanical control element is moved to cause the vertical relative movement.

16. A machine according to claim 15, wherein the device is arranged to be attached to the linkage which is subject to the vertical relative movement.

17. A machine according to claim 15 or 16, wherein the device is arranged to To be fastened to fastening elements (64) which remain stationary during the vertical relative movement relative to the frame (11).

18. Machine according to claim 16 or 17, wherein the device comprises a plurality of riders (61) which can be fixed at a selectable position relative to the rod or the fastening elements (64).

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