Abstract: A radio-operated parking barrier apparatus is provided that includes a base housing, a barrier arm including a shaft rotatably mounted in the housing, and a drive assembly disposed within the base housing that includes a pivot arm having a proximal end affixed to the shaft, and a driver having a reciprocally driven plunger movably connected to a distal end of the pivot arm. The back end of the driver is pivotally connected to the floor panel of the base housing to accommodate the vertical movement of the accurate motion that the end of the plunger must necessarily follow in converting the linear movement of the plunger into the rotation movement of the barrier arm around the shaft mounted in the base housing. The driver preferably utilizes a threaded shaft and drive nut to reciprocate the driver in operating the device. The drive assembly provides a simple and reliable linkage between the barrier arm and the base housing.

Abstract: An infra-red responsive fingerprint composition and method for manufacturing by sifting and mixing a minor proportion of finely divided carbon black (50 to 75 millimicrons) and a major proportion of infra-red responsive finely divided pigments containing milori blue (250 to 400 mesh), manganese dioxide (300 to 400 mesh), aluminum powder (1 to 75 microns) and mica (10 to 20 microns). A small amount of gum arabic as binder is included to facilitate adhesion of the print powder to latent prints. On white surfaces the fingerprint powder is black. On dark surfaces the fingerprint powder is brightly reflective so that when lifted or transferred to a white backing the color changes from brightly reflective to black. The reflective color becomes even more vivid under infra-red. Storage is preferably in tightly sealed containers in the presence of dessicant capsules to prevent moisture pick-up and caking of the gum arabic.