Abstract: A hatch securing mechanisms has a base attached to a hatchway and a hasp ached to a hatch lid. The base has an apertured retainer and a pinway element, the hasp being held between the retainer and pinway element during closure of the lid. A latch pin translatable in the pinway element has an angled tip which slides against a bevelled surface of the hasp to force the hasp into tighter, locked engagement with the base. The latch pin has a helical groove segment about the pin's axis, and a stud fixed to the pinway element engages the groove segment. The interaction of the stud and groove segment effects translation of the latch pin when the pin is manually rotated. The action of the latch pin also compresses an elastically deformable seal between the door and door frame so that the seal is increasingly effective against explosive blast pressures. The invention includes a lock mechanism for keeping the latch pin in a hasp retaining position unless the pin is manually moved.

Abstract: A distance measuring device includes first and second wheels having an endless belt looped about the wheels so the belt rotates as a ground engaging wheel. A hand contacting member is attached to the belt so as to provide positive sensory input to the device user when measuring distances.

Abstract: Disclosed is a positively locking latch or latch/hinge mechanism for use in pplications requiring quick connections and disconnections. The mechanism is comprised of a flange, a pin and base from which a plurality of plate extensions perpendicularly extend. The flange is dimensioned to fit snugly between two of the extensions. The extensions and the flange have axially aligned through holes of equal diameter. The pin axially translates through the aligned holes of the extensions and flange so that the flange is pivotally securable to the base. The diameter of the pin is only slightly less than the diameter of the holes so as to prevent radial movement of the flange relative to the pin axis. The mechanism includes a means for biasing the pin into an engaged position in which the flange is pivotally secured to the base and, alternately, a disengaged position in which the flange is removable from the base.