Abstract: A lift, a system and a method for elevating a trailer are provided. The lift may have an “A” frame for supporting the trailer. The trailer may be placed on the lift and secured to the lift. A cable attached to the lift is used to pull the lift and the trailer towards a wall. The cable, with the use of a pulley system, pulls the trailer in an upward direction towards the wall such that the lift and the trailer may be elevated in a vertical direction. The lift with the trailer may be attached to the bracket on the wall and locked into place. The lift and the trailer may be removed from the wall by releasing a lock.

Abstract: A lift, a system and a method for elevating a trailer are provided. The lift may have an “A” frame for supporting the trailer. The trailer may be placed on the lift and secured to the lift. A cable attached to the lift is used to pull the lift and the trailer towards a wall. The cable, with the use of a pulley system, pulls the trailer in an upward direction towards the wall such that the lift and the trailer may be elevated in a vertical direction. The lift with the trailer may be attached to the bracket on the wall and locked into place. The lift and the trailer may be removed from the wall by releasing a lock.

Abstract: A children's toy employing the domino effect in which the cascadable elements are hinged to linkable sections of track in such a manner that upon completion of the forward cascade a further cascade ripples through the same cascadable elements in the reverse direction.

Abstract: An electrooptic light modulator is constructed from a pair of subassemblies each comprising a lithium tantalate crystal fixed between two rigid, conductive electrodes. Such subassemblies may be individually tested to ensure the selection of a pair of crystals which are matching in thermal and electrical responses. The modulator construction is completed by arranging the selected subassembly pair with crystal optic axes in orthogonal relationship in order to negate the effects of natural crystal birefringence, and fixing the subassemblies between a pair of rigid pole pieces which, together with the electrodes, serve as heat sinks to moderate the effect of thermal fluctuations, and further stabilize the assembly against mechanical and piezoelectric perturbations.

Abstract: An electro-optical measuring system in a photogrammetric comparator or stereocompiler comprises a visible light transparent phase grating which is carried upon a surface of the photo support plate of the device. The grating is formed as a composite layer of .lambda./4 films of at least two dielectric materials of different refractive index which are deposited on the support in such a manner as to yield parallel bands in which the two film materials are in alternating sequence from band to band. As a result of this structure which ensures a constant physical and optical thickness with respect to transmitted imaging light over the whole granting pattern, image-degrading diffraction of the transmitted visible light is avoided, yet the grating pattern provides interfering diffraction in reflection which may be utilized in a precise displacement measuring system.

Abstract: The surveying system comprises a theodolite which provides digital data from electro-optical horizontal and vertical circle reading components and includes a level sensor which generates digital data relative to the attitude of the vertical axis of the instrument. Additional means are included for presetting instrument correction and scaling factors which together with angle and level data are processed by an on-board microcomputer to yield accurate digital displays of horizontal and vertical angles. Provision is also made for the input of digital slope range data from an electronic distance measuring instrument to be displayed directly or processed with horizontal and vertical angle data by the microcomputer to provide vector coordinates of the observed target. In response to operator selection from parameter and vector functions the control program cycles the processing of relevant data in order to provide a repeatedly updated display of any desired function.

Abstract: The surveying system comprises a theodolite which provides digital data from electro-optical horizontal and vertical circle reading components and includes a level sensor which generates digital data relative to the attitude of the vertical axis of the instrument. Additional means are included for presetting instrument correction and scaling factors which together with angle and level data are processed by an on-board microcomputer to yield accurate digital displays of horizontal and vertical angles. Provision is also made for the input of digital slope range data from an electronic distance measuring instrument to be displayed directly or processed with horizontal and vertical angle data by the microcomputer to provide vector coordinates of the observed target. In response to operator selection from parameter and vector functions the control program cycles the processing of relevant data in order to provide a repeatedly updated display of any desired function.

Abstract: Means for producing a counter reset pulse at the precise zero datum in an electro-optical measuring device comprises a sub-assembly including a light source, a patterned reticle, and a pair of photosensors, and a cooperating imaging reflector element. Each of the sub-assembly and reflector element are respectively mounted on the separate portions of the measuring device between which relative movement is effected during the measuring operation. Light from the source illuminates a pair of parallel transparent slots in the reticle pattern and is imaged back upon a second pair of transparent windows in the same reticle by the reflector element and is incident upon a pair of photosensors, each of which is associated with one of the windows. Equal illumination of each of the photosensors establishes the precise zero datum in the device and associated electronics provides a counter resetting pulse at that position.

Abstract: A level indicator providing a digital display of gravity-related attitude comprises a capacitive gravimeter pickup assembly the complementary capacitor pair of which are alternately switched, on an equal-time basis, into an R.C. oscillator circuit. Concurrently, each oscillator pulse train is switched, respectively, into the up- and down-mode of reversible counting means to yield a net oscillator frequency difference directly, digitally indicative of the degree of departure from a gravity-referenced level condition.