Abstract: A grade liner which is used in cooperation with grade stakes to determine the grade within a ditch. Means are provided for establishing a horizontal line of sight a selected rise distance "A" above a grade stake. Plumb means are provided which intersect the established horizontal sight line a given offset distance from said stake. The plumb means is calibrated such that the zero calibration is located a selected distance related to said rise distance "A" from the lower end of said plumb means. In a preferred embodiment of the invention, optical means, such as a target sighting rifle scope, are utilized in establishing a desired horizontal sight line. For the plumb means, a surveyor's tape measure may be utilized when coupled to a plumb bob, the length of which bob is selectively determinable and related to the distance said sight line lies above the grade stake.

Abstract: A leveling instrument for use in the building and construction trades comprises a sighting telescope embraced by one or more support members for sighting along horizontal distances, a spirit level frame having at least one bubble level tube mounted therein for indicating the horizontal alignment of the sighting telescope, and a leveling platform having a plurality of vertically adjustable legs for leveling the instrument on a support surface. The aforementioned components are maintained in relative alignment by means of flat planar mating surfaces without rigid mechanical connection therebetween in order to facilitate rapid assembly and disassembly of the instrument and compact storage. The sighting telescope includes a pair of intersecting crosshairs which may be manually adjusted in elevation, making it possible to sight along non-horizontal lines without physically tilting the leveling instrument as a whole.

Abstract: Angle measuring apparatus such as a transit has a pair of superimposed discs which are rotatable with respect to each other. One of the discs is rotatable with a viewing telescope support which has a vertically extending rotatable shaft received in a stationary shaft. A commercially available bearing is used between the shafts with the inner race fitted to the rotatable shaft and the outer race to the stationary shaft. The outer race of the bearing further carries the other of the disc.

Abstract: A measuring apparatus in which two casings are connected together each housing a coiled measuring means adapted for being selectively un-coiled and withdrawn from the casing or recoiled and retracted into the casing. A sighting device is provided on one of the casings to sight a target. The sighting means includes a level for determining when the sighting device is sighting along a horizontal line and a second level is provided to indicate when the casings are also appropriately arranged relative to a vertical line perpendicular to the first said horizontal line. Triggers are provided for the two coiled measuring devices and a brake is provided for each of the measuring devices. A digital display is employed and a counting circuit is provided for indicating the amount of measuring means which is uncoiled from the two respective casings. An alarm is provided to indicate when the unwound measuring devices are off line relative to the sighting device.

Abstract: These three new types of leveling instruments do not rely on spirit-level-bubbles in glass vials used in dumpy-levels and in tilting-levels, nor on the so called self-leveling pendulums used in the automatic levels. These new types of leveling instruments use a free mercury surface as a mirror to assure that the line of sight through the center of the cross hairs is horizontal, or has a very small but constant inclination from the true horizontal for all pointings to the leveling rods. In the most precise model, the mercury surface is used to autocollimate the line of sight through the center of cross hairs to be horizontal for every pointing. In the less elaborate models, the mercury surface is used to guarantee that the line of sight through the center of cross hairs has only a very small but constant inclination with the true horizontal. It is important that this inclination stays constant, and it can be adjusted to be less than one tenth of one second of arc if so desired.

Abstract: A sight for use on a bow for aiding an archer in sighting on a target from both elevated and level shooting positions. The sight includes an elongated sighting element which has a plurality of sighting beads thereon. The elongated sighting element is pivotably mounted on a horizontally extending shaft and is balanced so that the top bead on the elongated sighting element pivots about said horizontal shaft as the bow is tilted for automatically determining the proper elevation of the bow when shooting from an elevated position. The elongated sighting element may be locked in various arcuate positions when shooting on the ground.

Abstract: Fine adjustment of a surveying instrument telescope reference spirit level is effected by rotating the bubble vial of the level about an axis which is slightly angularly displaced from the longitudinal axis of the vial.

Abstract: The optical sighting instrument uses the image of a floating bubble in a spirit level as a self-compensating index mark to indicate a reference line of sight at a given angle to the earth's normal surface.

Abstract: An elevation and leveling adjustment arrangement for accurately locating pressure-to-current transducers, used in monitoring blood pressure during and post surgery, at an appropriate reference point relative to the patient. The pressure-to-current transducers are mounted to a platform or base which also has provided thereon level indicating means and optical means. The optical means in combination with the level indicating means is arranged to indicate when the base is properly leveled and the pressure transducers are at the same elevation as the reference point marked on the patient. In the case where an optical sighting means is employed, the reference point is directly viewable thereby. The platform further includes leveling adjust means which adjustably couples the base to a telescoping elevation adjust means, the latter of which provides fine elevation adjustment of the platform.