Solid material comminution or disintegration – Processes – Miscellaneous
Reexamination Certificate
2002-07-22
2004-07-06
Rosenbaum, Mark (Department: 3725)
Solid material comminution or disintegration
Processes
Miscellaneous
C241S101760, C241S101200, C366S282000
Reexamination Certificate
active
06758426
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates in general to certain new and useful improvements in a mixer or shredder apparatus of the type used for mixing and shredding of bulk material, such as farm feed material, and more particularly, to a mixing and shredding apparatus in which power to a shredding or mixing member can be reduced or increased by manual intervention without power interruption.
2. Brief Description of the Related Art
There have been several proposed and several commercially available mixers and shredders for mixing of bulk material or shredding of bulk material which utilize a tank containing the bulk material as well as one or more augers located with that tank and which rotate for accomplishing the shredding or mixing operation. The same apparatus is adapted for both mixing or shredding depending upon the type of auger which may used in the shredding tank and/or the rate of rotation thereof. In addition, and in the prior art, there are both horizontally arranged mixers and vertically arranged mixers.
Each of these proposed and commercially available prior art mixers generally comprise a mixer housing or tank forming a vat or chamber to receive the livestock feed or other material to be mixed or shredded, along with an auger extending into the housing and operated by an external power source. In the case of the vertically arranged mixer or shredder, the auger itself is vertically disposed.
Exemplary of such prior art shredders and mixers is U.S. Pat. No. 5,462,354, dated Oct. 31, 1995, for livestock stock feed mixer. In most cases, the shredder or mixer is used in a field environment as, for example, a farm, and is usually mounted on a chassis adapted for pulling movement. Again, the aforesaid U.S. Pat. No. 5,462,354 is exemplary of this type of arrangement. In these cases, the shredder or mixer may be pulled by a conventional tractor.
Generally, all farm tractors are provided with a means for coupling a power take off shaft commonly referred to as a “PTO” shaft. The engine of the tractor is operatively coupled to the drive wheels of the tractor for driving the tractor and which, in turn, pulls the mixer or shredder. The PTO shaft shares the power from this tractor engine for driving an auger or other rotating shredding or mixing member in the shredder or mixer.
Because of the increased demand for animal feed, the shredding and mixing tanks have been constructed with increasing sizes. In fact, there have been numerous cases where a farm owner will attempt to literally increase the size of the tank by extending the height the mixing tank in order to mix or shred a greater amount of feed material.
The amount of power which is consumed by the auger in the shredding or mixing tank is materially affected by the amount of bulk material in the tank. Moreover, the power required is a function of the density of the feed material. In addition, moisture which may be entrained in the material will also substantially affect the power requirements for rotating the auger of that mixer or shredder at a desired speed.
Because of the fact that the power to the shredder or mixer can vary with the power drawn by the wheels of the tractor, this power can be increased or decreased substantially thereby affecting the efficiency of operation of the shredder or mixer. In fact, if the tractor is traveling in a downhill mode, because of inertial forces, little power is necessary at that point in time for driving the tractor and, hence, there could be an excess of power literally delivered to the auger thereby causing the auger to overload and stress some portion of the entire mixing or shredding system.
Because of the developments in the shredding and mixing apparatus, the power required for rotation of the auger is constantly increasing, as aforesaid, thereby creating the need for variable transmission ratios between the engine and the auger. As a result, many of these shredders and mixers are provided with a gear box or transmission to change the power ratio to the auger of the shredder or mixer.
One of the main problems with the manual transmissions which have been used is the fact that in order to increase or decrease power to the auger, the user must change the gear ratio. Thus, if the user wishes to increase the power to the auger, he or she will select a lower gear ratio. However, with the manual transmission, the power train must first be disconnected. However, when power is interrupted to the auger, even momentarily, the additional problem arises, in that the power for restarting rotation of the auger can be considerable. Thus, forces are exerted upon the drive shaft and, in effect, the entire power train to the shredding and mixing apparatus. In some cases, this application of sudden power may result in damage to the drive shaft or other portions of the power train.
Another mixer/shredder apparatus which is effectively self-propelled by its own power source is that illustrated in U.S. Pat. No. 5,782,559, dated Jul. 21, 1998, for Self-Propelled Material Mixer. In this case, the power source is also shared, that is, used for driving the apparatus and also operating the auger of the apparatus. This power sharing gives rise to the types of problems mentioned above. An auger of the type which can be used in these mixing/shredding apparatus is disclosed in U.S. Pat. No. 5,732,892, for Self-Loading Auger.
One problem which arises is the fact that when the tractor or trailer is shifted into gear for driving, the torque which is used for operating the shredder or mixer is substantially reduced. This imposes additional stresses not only on the engine of the tractor, but on the shredding or mixing apparatus itself. These problems are identified in the aforesaid U.S. Pat. No. 5,462,354.
There has been at least one attempt to use an automatic transmission for incorporation in this drive train and which is shown in U.S. Pat. No. 5,462,354, as aforesaid. The automatic transmission, however, does not really solve the problems mentioned above and, in fact, in many ways, is less efficient than a manual transmission. In the case of the automatic transmission, the problem often arises that the speed of the power train is so low that the time required to mix and cut silage or other material can become excessive. There is little that the operator of the apparatus can do to affect the transmission ratio and, hence, the cutting and mixing process.
Another significant problem which has arisen in connection with the use of the automatic transmission is the fact that the transmission may literally cycle between gears. Thus, in a lower gear, the transmission may sense the need to switch to a higher gear. However, at the higher gear, the transmission may sense a need for more power and, hence, shift to a lower gear. This cycling, particularly if it becomes a constant cycling, can severely damage the transmission or other portion of the drive train.
There have been other attempts to account for variations in the loads imposed on a mixer or shredder and for the variations in loads on a power source therefor. One such attempt, for example, includes European Patent Application No. EP 0 880 890 A1, dated May 19, 1998, and which discloses a mixer in which the required drive power of the mixing or shredding member can be temporarily reduced during the initial stages of the mixing process and, particularly, when large chunks of material are present. Also, in European Patent Application No. EP 0 880 890 A1, dated May 19, 1998, a mixer or shredder is provided with a vertically arranged auger and which uses a reversible speed reduction gear arrangement to enable alteration of the speed of the motion of the mixing unit. In effect, a transmission arrangement is provided enabling selection of two different transmission ratios. Drive power can optionally be used for other purposes during this mixing process.
In U.S. Pat. No. 4,384,455, dated May 24, 1983, for hydraulic motor bypass apparatus, a fluid bypass system with a bypass valve automatically operates to stop motion of a feed ta
Rosenbaum Mark
Schaap Robert J.
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