A drawing head for use in drawing devices in which two flat members are mounted on a common axle and fixed relative to each other by means of spherical bodies disposed therebetween. The first flat member is associated with a means for moving the drawing head in the plane of the drafting board, and the second member with drawing scales through the intermediary of a square. The square is loosely mounted on the axle and is fixed relative to the second flat member by means of a friction clamp.

Solids and two liquids, each having different specific gravities, are separated in a centrifuge having a helical screw conveyor mounted within an elongated bowl tapered at one end. A group of solids discharge openings is disposed at the tapered end, and two groups of concentrically arranged liquid discharge openings, one for each separated liquid, are disposed at the other end of the bowl. One group of liquid discharge openings has an annular ring dam mounted adjacent thereto to serve as a weir;...

The drafting board has a drafting machine provided with a vertical track laterally movable across the board. A protractor support plate is vertically slidably mounted on the vertical track. A protractor head carrying vertical and horizontal scales is mounted on the lower portion of the support plate, the support plate having a narrowed extension track disposed parallel with and spaced from the vertical track, and the extension track having a longitudinally disposed keyway therein. A lamp support...

A carriage for use with guide means in drawing devices, in which two carrying rollers are mounted on axles stationarily secured to a base for the carriage, and two pressure rollers are mounted on axles secured to slides. The slides are disposed in slots provided in the base for the carriage at an angle relative to the longitudinal axis of the carriage and interconnected by means of a resilient member whereby the pressure rollers are constantly urged against the carriage guide means to preclude s...

The jam-fit connection between the tapered channel of a drafting machine protractor head scale arm and a like-tapered chuckplate of a drafting scale or rule is relieved by a split in the channel portion of the scale arm. A detachable retainer clip laterally containing the split portion of the scale arm ensures a firm union between the scale arm and the scale chuckplate during drafting operations, yet may readily be removed to allow the channeled portion of the scale arm to spread and release the...

A single operating lever control for locking and unlocking a rotatable head on a drafting machine wherein a lock pawl is released from engagement with the teeth of a ratchet disc. A thumb operated lever extends along the side of the conventional hand knob and may be operated in one of two ways. Upon direct inward movement, the pawl is released only so long as the thumb lever is held. In the other mode of operation, the thumb lever is locked so that the lock pawl is retained out of ratchet disc e...

A drawing head for use in drawing devices, in which a first flat member is, along with spherical bodies, integral with a bracket which connects the member with an arrangement used to move the head in the plane of a drafting board, and is rigidly fixed to a hub accommodating an axle. A second flat member is rigidly fixed to the axle and has cavities corresponding to the spherical bodies. The arrangement used to turn one flat member relative to the other member includes two washers mounted on the ...

The protractor unit according to this invention is characterized in that the support consists of a single piece and is provided with a least one toothed wheel axially open and formed integrally with the support, an annular peripheral cavity being also formed about said toothed wheel for receiving means for mutually detent-positioning a pair of teeth, said wheel being further provided with means for positioning a disk intended for locking said two movable portions in relation to the support, as a...

A drafting head for a drafting machine has two scaled straightedges directable at right angles to one another to define x and y coordinates, and carried by a member provided with an annular path of rotation. The member is constrained to the annular path for accurate angular adjustment of the straightedges, and the center line of this path passes through the vertex of the operating positions of the two straightedges. Each of the two straightedges in its operative position leaves clear drafting sp...

A drawing instrument in which a Y-rail is connected at right angles to an X-rail firmly secured to a drawing board along an X-coordinate axis and permitted to move in sliding motion relative to the X-rail, and in which ruler means with graduated scales is connected to a head mounted on a Y-carsol slidably mounted on the Y-rail. The head is provided with resilient means for urging the ruler means connected to the head to move upwardly away from the surface of the drawing board for facilitating op...