FARM (STATIONARY) MACHINERY. The machines to be described here are installed in buildings on the farm and are used mainly in connection with the preparation of foodstuffs for livestock. They may be operated by hand or power. In the latter case some form of transmission machinery must be employed to enable the power unit (steam or oil engine, agricultural tractor or electric motor) to drive the machinery. Where only one machine is used this is driven direct by a belt from the engine, but where a number of machines are installed it is usual to employ shafting and secondary pulleys (i.e., belt wheels) for driving each machine. When several machines are to be operated simultaneously, the drive from the engine is taken by a belt to the shafting which car ries the pulleys and belts for operating the various machines. Fast and loose pulleys are usually employed side by side so that by moving the belt from one to the other on the shaft a particular machine may be started or stopped without interfering with the operation of other machines. In some cases clutches may be used instead of fast and loose pulley. Stationary machines must be driven at the correct speed as specified by the makers, if efficient service is to be secured, and care must be taken to see that pulleys of the correct size are used.
The chaffing or chopping of hay and, straw into short lengths is done to facilitate mixing with other food stuffs and to assist the feeding of livestock. In a modern chaff-cut ter the hay or straw is fed into a trough, at the bottom of which is a moving belt for conveying the uncut fodder to toothed rollers : these rollers hold the long stalks while the knives descend and cut the fodder into the required lengths. The knives which may be convex, concave or straight are usually attached to the spokes of the flywheel (which is connected to the driving mechanism by a spindle or shaft) , and so set that they cut the fodder against the mouth of the machine as it is pushed forward by the feeding roll ers, which are driven by gearing from the driving shaft of the machine. The length of cut is varied by adjusting the feeding trough : the speed of the knives can be varied to suit the cut, and some machines have three-speed gearing for this purpose. The upper feeding roller is usually kept in position by a spring so that it can adjust itself to deal with uneven thicknesses of fodder. Power-driven chaff cutters are required in Great Britain to have a cover over the knives and to have a device to prevent the hand or arm of the operator being drawn into the machine. In hand-fed machines there is usually a device for reversing the direction of rotation of the feeding rollers in the event of the operator's arm being drawn along with the fodder. As an additional safeguard, idle rollers may be placed on the outside of the feeding rollers. Large machines may have dust-extractors and bagging attach ments or blowers for conveying the cut fodder to a store.
These machines are used principally for milling cereals, maize, pulse, etc., before feeding to livestock, so as to aid digestion, as, for example, in the case of crushed oats, or to facilitate mixing with other fodder, e.g., ground corn or chaffed hay or straw. The degree of grinding is very coarse compared with flour, though some mills used by farm ers can grind wheat sufficiently fine for making whole-meal bread. In America the machines described below are known as "feed grinders" or "feed-mills" and may have attachments for cutting pea-vines, peanut-hay and other roughage which is afterwards ground. Such machines are often fitted with bagging or blowing devices. Crushers or kibblers are used mainly for oats, maize and linseed, which are bruised, broken or flattened without being ground into a meal. The essential components are two roughened or fluted rollers which crush the corn as it passes between them. One roller is fixed and the other adjustable so that different grain can be crushed or the fineness of crushing varied. In some machines the fixed roller has a much larger diameter than the other and serves as a flywheel. The grain is fed from a hopper by gravity and the machine may be either hand- or power-driven. Grist or grinding mills are invariably power-driven and utilise small disks (smooth, rough or fluted) revolving at a high speed in a vertical plane for grinding the corn which is fed from a hopper. The mill is placed on a suitable stand and must be firmly fixed to a solid foundation. Stone was originally used for the grinding disks, but chilled metal and artificial or composition stones are now com monly employed. The disks may be flat or conical in shape and provision is made for adjusting them to vary the fineness of grind ing. Where a farmer desires to grind whole-meal flour the mill may be provided with a meal-sifter. Combined crushing and grind ing mills are also made : the essential components resemble those described above, but the hopper is usually divided into two com partments so that both operations may be carried on simultane ously.
These machines are made for hand and power operation. They consist of a feeding slot and one or two pairs of toothed or spiked metal rollers which break the cake as it passes between them. The distance between the rollers can be varied to alter the size of the broken pieces : these are passed over a riddle in order to separate the meal and fine particles from the nuts. The breaking rollers should be securely protected or covered so that there is no possibility of the man feeding the machine being trapped by them, and any cog wheels used for driving the rollers should be encased by a metal covering.
These machines are used mainly for swede turnips which are hard. Mangolds and white or soft turnips are usually fed whole, though they may occa sionally be sliced. Cleaners consist of a number of iron bars joined together in the form of an open cylinder which can rotate in an inclined plane. The roots are fed into a hopper at one end and pass by gravitation along the cleaner as it rotates into the cutter or pulper, any loose soil falling through the iron bars in the proc ess. The rate of cleaning is regulated by altering the inclination of the cylinder to the horizontal. Cutters or pulpers are of vari ous types and may be operated by hand or power. The simplest hand machine is the stamp or lever cutter which slices the roots by means of a receptacle with knives set in echelon at the sides and a hinged handle with a block of wood for pressing the roots between the knives. The commonest types work on the rotary principle and have a hollow barrel or drum carrying cutting devices of various shapes on the periphery. The roots are fed from a hop per and the barrel, which is mounted on a frame, can rotate in both directions so that the roots can be sliced by one set of knives and cut into fingers by the other. It is usual to slice roots for cattle and cut them into fingers for sheep. For pulping roots, rotating disks with cutting projections are used, but these machines appear to be going out of use. Power root-cutters may have an elevator for feeding the roots or for disposing of the roots after cutting.
There are no general statutory re quirements for the protection of farm-workers as there are for the protection of factory-workers. Manufacturers make it a rule to provide guards for dangerous machinery, but many precautions must, of necessity, be left to the user. All flywheels, pulleys, belts, shafting, cog wheels, etc., which are within reach of the workers should be securely fenced or protected in order to prevent acci dents. Many accidents can be prevented by laying out the shafting and machinery in such a way as to remove the belting and moving parts as far as possible from the workmen.
See also AGRICULTURAL MACHINERY.
Safeguarding of machinery and other dangerous plant used on farms, Ministry of Agriculture and Fisheries, London.