Abstract: A rotary tiller for maintaining cross country ski trails has a rotary shaft with at least one array of radially extending first cutters flanked by laterally adjacent arrays of radially extending second cutters. The radial lengths of the first cutters are greater than the radial lengths of the second cutters. The first cutters are arranged to till a center ski track and the second cutters are arranged to till pole tracks on either side of the ski track, with the ski tracks having a tilled depth greater than that of the pole tracks.

Abstract: An apparatus for forming cross country skiing tracks in a snow covered surface. The apparatus is adapted to be towed behind a vehicle and includes a trailer frame connected to the vehicle in a manner permitting the frame to pivot at least in the horizontal plane. A blade and a ski track device are carried by the frame. The blade is adapted to contact and recondition the snow covered surface, and the ski track device is adapted to form skiing tracks in the thus reconditioned snow covered surface. The blade and the ski track device are each fixed against pivotal movement relative to the frame in the horizontal plane. Thus, the trailer frame, the blade and the ski track device pivot in the horizontal plane as a unit relative to the vehicle.

Abstract: The dimensions of a product passing through the finishing block of a roll rolling mill are measured. Where the dimensions of the product exiting the last finishing stand are out-of-tolerance, a calculation is made to determine the extent to which the roll parting of the work rolls of one of the two last finishing stands must be adjusted to bring the product into tolerance. Based on the calculated adjustment, progressively smaller adjustments are made to the roll partings of the work rolls of the upstream finishing stands to distribute the work which must be performed on the product to bring the product into tolerance.

Abstract: The invention is directed to a method of applying a corrosion-proof and wear-resistant coating to the piston rod of a hydraulic ram which is intended to be used in an underground mine working, or in similar workings. The method comprises the steps of applying a layer of nickel to the piston rod using a currentless nickel-plating process, and then applying a microcracked hard-chromium layer to the nickel layer. The nickel layer is of high density, tensile strength and ductility. Before the application of the microcracked hard-chromium layer, the previously-applied nickel layer is activated electrolytically in a sulphuric acid bath, in order to improve the adhesion of the hard-chromium layer to the nickel layer.

Abstract: A cutter bit assembly comprises a holder and a cutter bit. The holder is formed with a pocket into which the cutter bit can be inserted. The cutter bit is retained within the pocket by means of an arcuate wedge inserted into a tapered gap formed between respective curved support faces formed on the cutter bit and the holder.

Abstract: In a tunnel driving apparatus, and particularly such apparatus where a work face is supported by fluid, a cutting appliance is employed which is composed of a swinging arm carrying a cutter head. The arm can range over the face to detach material therefrom with the cutter head. Means for driving the cutter head is accommodated entirely within the arm itself and a conduit or the like extends through the arm and serves optionally to remove debris by suction or to convey pressure fluid to the face to assist the cutter head.

Abstract: A mine roof support unit has a roof shield for supporting the roof of a mine working, and a goaf shield for screening off the goaf space of the working. The mine roof support unit is provided with dust suppression means constituted by a flat-section spray nozzle arranged along the front edge of the roof shield, or along the top edge of the goaf shield. The spray nozzle is directed upwardly away from the roof support unit and towards the goaf space.

Abstract: A hydraulic ram for use as an advance ram in mining operations has a plurality of permanent magnets embedded in its piston rod. At least one sensor is associated with a guide bush fixed to the piston rod end of the cylinder of the ram. The or each sensor is accommodated within a respective pocket formed in the guide bush. The pocket(s) can be closed off by a detachable closure member.

Abstract: A composite doctor blade with non-homogeneous stiffness properties and having a plurality of juxtaposed fibrous layers which are encapsulated in an epoxy resin. The composite blade has a fibrous core, intermediate uni-directional graphite fiber layers and outer fibrous layers. The uni-directional graphite fibers in the intermediate layers are oriented in the machine direction.

Abstract: This invention relates to a ball valve having a valve body with a bonnet bore communicating with a through fluid bore. A valve seat in the valve body surrounds the fluid bore axis. A bonnet with a stem bore extending therethrough is received in the bonnet bore. An operating stem is journalled for rotation in the stem bore. A ball is connected to the stem and located in the fluid bore. The ball has a through passageway. Rotation of the stem causes the ball to rotate eccentrically between an open position at which the ball is spaced from the valve seat with its through passageway aligned with the fluid bore, and a closed position at which the ball blocks the fluid bore by being wedged into sealing engagement with the valve seat. The ball is externally contoured to provide both a clearance from the valve body to accommodate its eccentric rotation, and a stop which is engageable with the valve body to positively locate the ball in its open position.

Abstract: Apparatus is provided whereby maximum options for the treatment of steel rod in direct sequence with rolling are available within a single piece of equipment, all on a single treatment line, and all at convenient, labor free, push-button control. Maximum application of heat to the rod is provided for heat treating, slow-cooling or intermittent reheat cooling or treating, and alternatively maximum application of cooling air is available by means of individually controllable air ducts and guides associated with each roller conveyor for applying air at different pressures both across and/or along the conveyor. Special means for applying forced air to the rod through outlets in contact with the rod assure maximum penetration of cooling air into the dense parts of the lay. Special forms of rollers are provided for applying cooling air to the rod and to the rollers as well as for supporting rod during heat treatment.

Abstract: An apparatus for assembling tubes, bars, rods and other like elongated elements preparatory to bundling the same.

Abstract: A compact hydraulic control device for use with mining apparatus is composed of a housing block containing tappet-operated valves. A multi-part cam shaft serves selectively to operate the valves by displacing the tappets by manual control effected by external levers. To automatically restore the cam shaft back into a neutral position as a "dead-man's handle" restoring system use is made of a pair of piston and cylinder assemblies mounted as detachable cartridges in parallel locations within bores in the housing block and having push rods which act on a cam of the cam shaft under the action of hydraulic or pneumatic pressure medium.

Abstract: A level winding apparatus for coiling elongated material, such as wire or tube, into a compact coil. A non-contacting device located near a spooling arrangement for coiling consists of at least two parallel spaced-apart arm arrangements each located on either side of the material as it is wound onto a spool. Each arm arrangement is adjustable to accommodate the transverse dimension of the material and carries a photoelectric control unit having fiber optic carrying cables connected to transmitter and receiver means for creating a high intensity light field extending at least a length to accommodate a range of paths of travel the material takes from the feeding means to the spool starting from an empty spool to build-up of the coil. An undesirable approach angle of the material onto the spool is detected and a correction is made so that the formed coil contains a number of superimposed layers each with a number of evenly and closely abutting adjacent windings.

Abstract: A novel, heat curable, liquid polymer composition is disclosed which comprises a modified urethane oligomer containing terminal ethylenic unsaturation and a free radical catalyst. In a preferred embodiment, the polymer composition further includes at least one additional component selected from a reinforcing agent and a filler; the cured composition demonstrates enhanced impact properties and is particularly useful in automotive body constructions.

Abstract: An arrangement for and method of operation for threading strand-like material such as wire or tubing around a grooved type, rotatable block assembly wherein tension is needed to pull the material through a reduction die, includes a plate mounted on the same shaft as the block. This plate supports three devices used in a time sequence relationship in said threading operation for the drawing process: a gripper arm for grasping the pointed end and introducing it into the groove; a shear for severing the pointed end; and a deflector mechanism for guiding the material away from the block assembly. Clutch assemblies are selectively operated to place the plate into and out of engagement with the drawing block for the plate's rotation therewith and it's non-rotation.

Abstract: A method and apparatus for quenching steel rod in a high speed rolling mill is provided wherein a liquid coolant is preliminarily applied to the rod prior to its exiting from the mill finishing train in order to increase the column strength of the exiting rod by lowering the surface temperature thereof to less than about 950.degree. C. Thereafter, as the rod progresses through additional liquid cooling devices on the way to the mill laying head, tractive forces are applied to the rod. The aforesaid increase in rod column strength acts in concert with the application of tractive force to insure that the rod has sufficient rigidity and forward momentum to pass from the finishing train through the liquid cooling devices and to and through the laying head.

Abstract: A mobile mine roof support assembly has three mine roof support units coupled together by a common transverse beam. Roller devices are mounted beneath the floor sills of the support units. The roller devices are spring biased away from their floor sills so that they can lift the floor sills away from the floor of a working when the assembly is to be moved. At least one roller device of each support unit is a steerable roller device so that the assembly can be steered round bends. Each steerable roller device is pivotally mounted on its floor sill about a vertical axis, and is provided with an associated steering device. The steerable roller devices are preferably coupled together by means of a common steering device.

Abstract: In a microwave tube of the type wherein an electron beam emitted by an electron gun is focused and caused to interact with an input high frequency wave at a high frequency circuit unit by magnetic flux generated by a periodic permanent magnet assembly, and the electron beam after the interaction is collected by a collector unit, the portion connected to the output unit of the high frequency circuit unit comprises a column-shaped waveguide member having an end surface comprising a portion of the wall of a cavity at the end of the high frequency circuit unit, the member being bored with a central aperture at the center axis to allow electron beam to pass from the electron gun to the collector unit. A waveguide for guiding the electromagnetic waves from the end surface to the output unit is also provided, and the end surface is shaped like a fan.