Abstract: A seed planter has at least one rock shaft carrying a rank of planter assemblies. Each planter assembly includes a torsion joint assembly connected to the rock shaft, a planting equipment linkage connected to the torsion joint, a planting equipment yoke connected to the linkage and planting tools or equipment connected to the yoke. The planting equipment linkage is a modified parallelogram linkage that keeps the planting equipment in consistent alignment over the ground even as the seed planter traverses irregular terrain. The seed planter includes a stop mechanism that limits the amount of permissible rotation of the torsion joint on the rock shaft. A stop plate is attached to the torsion joint housing for rotation with it relative to the rock shaft. An edge of the stop plate faces the rock shaft and has a jaw opening defined by upper and lower jaws that at least partially encompasses the rock shaft.

Abstract: A portable seed spreader for distribution of bulky and irregular size seeds over a local area. The spreader includes a U-shaped frame that carries a housing having a first seed bin and a second seed bin. A first transverse shaft is mounted to legs of the frame and extends through the first seed bin. The first shaft carries agitators for mixing and stirring the seeds in the first seed bin. Discharge slots are located in a bottom wall of the first seed bin. A second transverse shaft is mounted on the frame and extends beneath the bottom wall of the first seed bin. The second transverse shaft carries picker wheels that extend through the discharge slots into the first seed bin to pick seeds therefrom and draw them through the discharge slot. The shafts are connected so that rotation of one transverse shaft as by a hand crank, an electric motor or a wheeled mechanism, results in rotation of the other.

Abstract: An operational amplifier is disclosed having a phototransistor at its input for reading a bar code wherein the saturation point of an operational amplifier is controlled by a clamping feedback voltage having a positive control controlling the saturation point of the operational amplifier while prohibiting the operational amplifier from reaching its saturation point.

Abstract: This invention is directed to an optical card reader in which the cards to be read have a format arranged in columns and rows. A row of timing marks or slots is formed in the card for each column of data. The card is driven past a read head block that directs the light to the card in which the reflected light is received through a shaped aperture or orifice so that a positive indication of the marked area is detected. The signal is applied to an operational amplifier for further treatment. There are a plurality of light sources and sensors transversely arranged in the read head block.

Abstract: A tactile feel device which provides a characteristic resistance to movement, and breakaway feel to signal the operator that movement and accompanying function, such as switching, has been accomplished. Resistance to movement is provided by spring biasing means for the initial stroke of the device, by spring biasing means plus magnetic force at the end of the initial stroke, and by spring biasing means only, after magnetic breakaway at the end of the initial stroke, to provide a characteristic breakaway feel. The device is shown and described in connection with a light pen which generates a signal when pressed against a cathode-ray-tube faceplate. The characteristic breakaway feel signals the operator that the tip or probe of the pen has been sufficiently pressed against the cathode-ray-tube to generate the appropriate signal in the light pen.