FR2648669A1 - Improvements made to rotating-drum silo unloaders - Google Patents

Abstract

The invention relates to a rotating-drum silo unloader. It comprises a pivoting gantry 11 formed of two arms 14 articulated by one of their ends to a mixing box 22 and at their other end carrying a silo unloading drum 26 of horizontal axis, which can be driven rotationally about its axis by driving means, the said drum being equipped on its outer cylindrical wall with cutting tools 28 which make it possible to cut up the products stored in the silo, and being protected on its upper part by a curved casing 38 leaving a small clearance with the cutting tools. Following each cutting tool 28 with respect to the direction of rotation of the drum is fixed a spoon-shaped palette 32 intended to eject the product detached from the silo 30 using an associated tool. The casing is internally lined by a fairing 40 which runs along the drum over approximately a third of its circumference and which is separated from it by a gap which is just enough to allow the passage of the tools and palettes.

Description

 Improvements to silage cutters i rotary drum.

 Silage unloaders are machines commonly used in agriculture, and more particularly in the livestock feed industry, for unloading a food product stored in a silo. A silo unloader is generally combined with a mixer in which the product taken is mixed with other ingredients in order to prepare an elaborate feed for livestock.

 Silage unloaders generally comprise a pivoting gantry, formed by two arms articulated by one of their ends on a mixing box and carrying at their other end a silage drum of horizontal axis, being able to be driven in rotation around its axis by motor means, said drum being equipped on its external cylindrical wall with cutting tools which make it possible to cut the products stored in the silo. The drum is covered on its upper part with a curved casing making a slight play with the cutting tools in the front part of the drum and progressively moving away from the latter towards the rear until its rear end which opens out to- above a receiving tank, such as a mixer.

 In operation, the silage drum is driven at high speed counterclockwise. When it attacks the vertical front of a silo, its cutting tools cut the ensiled product into a surface substantially in the shape of a quarter cylinder and eject it towards the casing from where it is projected into the mixer.

The capacity of the silage cutters thus equipped is relatively satisfactory in the silage removal of maize harvested at a humidity rate of + 60%, but for less consistent or light products, such as grass or beet pulp, their yield is low. , for the following reasons:
- between the point where the cutting edges start to move away from the surface of the silo and the front edge of the casing, there remains an area not protected by the casing, in which the blowing effect is attenuated, so that 'there is turbulence,
- since the casing moves further and further back from the drum, turbulence occurs in the space between the tambqur and the casing. The product bursts and is thrown in all directions instead of being guided towards the outlet of the housing.

 The present invention aims to remedy these drawbacks by proposing a silage cutter having an excellent yield, by the fact that the blower effect is reinforced and the zones of turbulence practically eliminated.

The subject of the invention is therefore a silage unloader of the type mentioned above and which is characterized in that:
- following each cutting tool, relative to the direction of rotation of the drum, is fixed a pallet in the form of a spoon intended to eject the product detached from the silo by the associated tool,
- the front edge of the housing advances practically to the area where the tools begin to no longer be in contact with the front face of the silo,
- The casing is internally lined with a fairing which runs along the drum over about a third of its circumference and which is distant from the drum by an interval just sufficient to allow the passage of tools and pallets.

 The pallets ensure better handling of the products detached from the silo than in the case where the drum is equipped only with sharp tools. On the other hand, the silo's cutting surface and the fairing define between them a practically uninterrupted cylindrical surface which surrounds the drum over about two thirds of its circumference. The blower effect is provided with the same intensity and without turbulence throughout this area, up to the rear end of the fairing.

The invention will now be described in detail with reference to the appended drawings which represent a nonlimiting embodiment of the silage cutter according to the invention and in which:
FIG. 1 represents the silage cutter according to the invention mounted on a mixing box;
Figure 2 is a longitudinal sectional view of the silage cutter; and
Figure 3 shows a similar sectional view of a silage cutter according to the known prior art;
The silage cutter 10 shown in Figures 1 and 2 comprises in a manner known per se a gantry 11 consisting of two bent arms 12, 14 connected together by spacers 16, 18 and mounted pivotally by one of their ends around a horizontal shaft 20 carried by a mixing box 22. At the other ends of the arms is fixed the horizontal shaft 24 of a rotary drum 26 which can be driven by suitable motor means, in the direction indicated by the arrow f in FIGS. 1 and 2 .

 On the external cylindrical surface of the drum are fixed a plurality of cutting and cutting tools 28 intended to cut and detach from a product stored in a silo 30, plots or particles of this product and to eject them towards the box 22.

 According to the invention, the training of the cut particles and plots is improved thanks to the provision of pallets 32 in the form of spoons fixed on the drum following each cutting tool. Thus, the plots which have been cut by the tools are immediately driven upwards by the pallets.

 The assembly of the arms 12, 14 and of the silage drum 26 can be pivoted around the axis 20 by a hydraulic or pneumatic cylinder 34 or by any other suitable motor means. The silage drum attacks by its cutting tools the silo 30 from top to bottom and as it descends, it cuts there a cylindrical front surface 36 of large radius and therefore substantially vertical. Zone A on which the tools act, has a cylindrical shape of approximately 120 at all times.

 The particles ie product which are ejected upwards by the tools and by the pallets are guided towards the mixing box 22 by a casing 38 internally lined with a fairing 40, of cylindrical shape, concentric with the drum and surrounding the latter on its part about a third of its circumference.

 As shown in FIG. 2, the front edge 42 of the fairing advances up to approximately the limit line 43 of zone A where the tools begin to move away from the front surface 36. The rear edge 44 of the fairing flares upwards so as to form a weir which opens above the box 22. As a result, a practically uninterrupted tubular space, formed by the surface A and the fairing 40, surrounds the drum approximately on two thirds of its circumference. The products detached from the silo are therefore entrained in said space by a constant blowing effect free from any turbulence.

For comparison, there is shown in Figure 3 a silage cutter according to the prior art. This drum has the following disadvantages:
- it is not fitted with ejection paddles, so that the product detached from the silo is badly entrained,
- It is protected only by a casing 38 which moves further and further away from the drum from its front edge to its discharge edge. No internal fairing is planned: the product is therefore poorly guided in the casing due to the turbulence created between the casing and the drum,
the front edge 42 of the casing is set back with respect to the limit line 43 of zone A where the tools begin to separate from the front face 36. The intermediate zone B formed between line 43 and the front edge 42 of the casing is therefore the site of a loss of the wind tunnel effect. The ejected products are braked and do not flow well to the housing.

Claims (1)

 CLAIM  Rotary drum unloader intended for unloading a product stored in a silo, of the type comprising a swiveling gantry (11), formed of two arms (12,14) articulated by one of their ends on a mixing box (22) and carrying at their other end a silage drum (26) with a horizontal axis, which can be driven in rotation about its axis by motor means (34), said drum being equipped on its external cylindrical wall with cutting tools (28) which make it possible to cut the products stored in the silo, and being protected on its upper part by a curved casing making a slight clearance with the cutting tools, characterized in that:  - following each cutting tool (28), relative to the direction of rotation of the drum, is fixed a pallet (32) in the form of a spoon intended to eject the product detached from the silo (30) by the associated tool,  the front edge (42) of the casing (38) advances practically as far as the zone (43) where the tools begin to no longer be in contact with the front face (36) of the silo,  - The casing is internally lined with a fairing (40) which runs along the drum over about a third of its circumference and which is moved away from it by an interval just sufficient to allow the passage of tools and pallets, said fairing being arranged to so as to follow, without interruption, the surface portion (A) being cut on the front face (36) of the silo.