Abstract: An earth boring bit has thrust surfaces with enhanced cooling features. The bit has a body with three depending bearing pins. A cutter having an axial cavity is mounted on each bearing pin. The bearing pin and the cavity have mating thrust shoulders. Hard metal inserts or buttons are spaced around each of the shoulders and secured interferingly in mating holes. The buttons in one of the shoulders protrude slightly from the shoulder to allow air to flow past.

Abstract: An earth boring bit of the air cooled bearing type has features to improve cleaning of the borehole. The bit has three bit legs, each with a depending bearing pin that receives a rotatable cutter. Bearings are located between the bearing pin and the cutter. Passages communicate drilling fluid from the drill string to the bearings. A slot between the bit leg and the backface of the cutter enables air to be discharged from the bearing pin into the borehole. The portion of the slot on the lower side of the bearing pin is greater in cross-sectional flow area than the portion on the upper side. The portion of the slot on the lower side exposes the outer ends of the roller bearings to the borehole.

Abstract: A security device for controlling the ignition circuit of a vehicle provided with a steering lock 11. The device comprises an electrical circuit having: a security ignition circuit switch means CO32 for opening and closing said ignition circuit independently of any manually operable ignition circuit switch means; and a steering lock control switch means MS1 connectable to said steering lock 11 and having disabling and non-disabling operating conditions, corresponding respectively to locked and unlocked positions of the steering lock 11, for respectively disabling and not disabling said vehicle with respect to starting thereof. A plurality of user actuable first switch means 3 is arranged so that operation thereof is necessary in a predetermined sequence to close the security ignition circuit switch means CO32. An alarm connection means CO52 is connected to alarm means SIREN and arranged for activation in response to actuation of said first switch means 3 in an incorrect sequence.

Abstract: A stabilizer for attachment to drill string in large diameter earth boring or shaft drilling to center the drill string and maintain alignment of the drill bit. The stabilizer has an inner hub that is rigidly secured to the drill string above the bit. A rubber tube inside the inner hub is compressed to lock the inner hub to the drill string. An outer hub encircles the inner hub. A bearing is mounted between the inner hub and outer hub to allow rotation with respect to each other. The bearing includes a frusto-conical ring in contact with individual pads that are exposed to the drilling fluid. A number of arms extend radially outward from the outer hub to centralize the drill string. The arms are telescopingly received in the outer hub and are pinned together by tie bars at their outer ends to allow them to be quickly removed.