Abstract: A paper feeding device for automatic drafting machine in which paper is fed in a predetermined direction by drive rollers and pressure rollers that are in resilient contact with the drive rollers. A writing implement is shiftably disposed in a right angle direction to the feeding direction of the paper, and the writing implement abuts on the paper. A predetermined pattern is drawn on the paper by mutual operations of the transfer of the writing implement and the transfer of the paper in the feeding direction. Underlay rollers are disposed in parallel to the transfer path immediately below the transfer path of the writing implement. The direction of drive and rotation of the underlay rollers is identical with that of the drive rollers, and a circumferential speed of the surfaces of the underlay rollers is set slightly higher than a circumferential speed of the drive rollers.

Abstract: An automatic drafting machine in which the paper is disposed on drive rollers and the paper is sandwiched by the drive rollers and pressure rollers in resilient contact with the drive rollers, and a writing implement is shiftably disposed in a right angle direction to the feeding direction of the paper along the horizontal surface of the paper, and guides for mounting the paper are disposed on both sides of the track along which the writing implement shifts, and an air blowing opening for supplying downward air pressure on the paper is disposed in the vicinity of the outer end portions of the guides in the feeding direction of the paper.

Abstract: A scale balancing device for balancing the weight of the scales of a universal parallel ruler, the device having a head structure having the scales rotatably mounted thereon, a rotating member rotatably mounted on the head structure separate from the scales, the rotating member and the rotatable scales being rotatably interlocked, and a spring having one end rotatably connected to a point on the rotating member eccentric to the axis of rotation thereof and the other end rotatably connected to a non-rotatable part of the head structure, the spring, when the scales are rotated to a position vertically in line with the axis of rotation thereof, having substantially no tension therein and when the scales are rotated ninety degrees from such position, having tension for exerting a maximum force on the eccentric connection point on the rotating member and sufficient in magnitude and having a direction which substantially cancels out the torque on the rotating member from the weight of the scales.

Abstract: In an instrument for converting the rotary motion of the feed shaft of a machine to a pulse train having a direction component and for counting and displaying the pulse train as counted by a reversible counter, a digital measuring device arranged such that its reversible counter does not count pulses generated by the idling rotation of the feed shaft due to play in the feed system of the machine, thereby digitally counting and displaying the correct transfer distance or feed ratio of the transfer unit of the machine.

Abstract: A digital measuring device for a machine tool in which a transfer member is fed in a predetermined direction by the manual rotation of a lead screw; the improved digital measuring device includes: a pulse generating unit for converting a rotational motion of the lead screw to a pulse signal having a direction component, a microcomputer for storing accurate transfer data of a feed system of the machine tool for each address signal based on the pulse signal, and a display unit connected to an output side of the microcomputer, whereby the address signal is inputted to the microcomputer on the basis of the output pulse of the pulse generating unit, and the previously measured accurate transfer data of the feed system of the machine tool is called out from the microcomputer, and the transfer data is displayed on the display unit.

Abstract: A plotting head for use in a drawing machine comprising a housing attached to said drawing machine; a lead holding means installed for vertical movement within said housing and having a vertical through hole; a bias means disposed above said lead holding means and imparting it a continuous descending tendency; a long cover means covering said bias means; a chuck means disposed for vertical movement in the through hole of said lead holding means, provided with a vertical lead inserting hole and having at the lower part a collet portion arranged to shut for clamping the lead and open for releasing the lead depending upon the vertical movement of said chuck means; a gripping means disposed for vertical movement on the bottom wall of said housing and operating to grip the top of the lead; and an actuating means operating to allow said lead holding means to ascend against the force of said bias means.

Abstract: A straightedge supporting device for rail type drawing instrument which has a cross rail capable of being manually shifted in a desired direction on a drawing board while remaining in a predetermined orientation, a head supported by a longitudinal rail on the drawing board, a ruler mounting plate mounted on the head for rotation in a plane parallel to the surface of the drawing board, a fixing element for detachably fixing the ruler mounting plate to the head and disengaging it therefrom, and a straightedge mounted on the ruler mounting plate.

Abstract: A device for rotatably attaching rollers to a carriage in such a maner that the peripheries of the rollers are maintained in engagement with rail surfaces arranged longitudinally of a rail along which the carriage is adapted to move in sliding movement. The device comprises presser means provided in the carriage and comprising members each associated with one of the rollers, each member being formed therein with a inclined surface and adapted to move in linear motion. At least one of the rollers is supported for movement toward and away from the associated rail surface at right angles thereto. The device further comprises resilient means adapted to resiliently urge the pressing means to bring the inclined surfaces of the presser means into resilient engagement with roller support means whereby the rollers can be maintained in resilient engagement with the respective rail surfaces.