Abstract: An apparatus for clearing obstructive tissue from a body vessel or enlarging the lumen of the vessel comprises a balloon catheter which is insertable into the vessel of a patient to position the balloon in the area to be enlarged or against the obstructive tissue. A syringe is provided to incrementally inflate the balloon with a reasonably incompressible fluid to apply pressure against the inside of the vessel for opening the vessel. A pressure transducer senses fluid pressure in the balloon and an interval timer is used to monitor the rate of change in this fluid pressure. The rates of change in fluid pressure between the incremental inflations are monitored to determine vessel compliance, to determine when the stenosis is cleared, and to indicate when the vessel is stretched to, or near, its elastic limit.

Abstract: A tamper-proof and wear resistant identification card having a support layer, a strip of magnetic tape for containing encoded information, transparent layers covering the front and rear surfaces of the support layer and a screen of optically-readable encoded information on a surface of one of the transparent layers.

Abstract: A compact portable housing encloses a piezoelectric element which receives short pulses from a pulse generator circuit controlled by a ramping waveform generator circuit so that the element and the adjacent speaker portion of the housing produce a frequency modulated loud sweeping sound. The housing also encloses a detector switch for sensing a disturbance, and the sensitivity of the switch may be adjusted according to the position of the housing. The detector switch actuates a timer circuit which is armed or disarmed by moving a combination code switch having code wheels projecting from the housing.

Abstract: An electrical component is supported within a housing molded of a plastics material, and the housing has an external groove which is interrupted by a plurality of peripherally spaced slots extending axially through the forward end portion of the housing. The slots provide for partially collapsing the forward end portion of the housing in response to pressing the housing into an opening within a panel so that the panel snap-fits into the groove. A retaining member is also molded of a plastics material and is mounted on the forward end portion of the housing to cover the slots. The retaining member has a corresponding plurality of circumferentially spaced and integrally molded ribs which are pressed axially into the slots to lock the housing firmly to the panel. The slots and ribs may have interfitting teeth to produce a permanent lock, and the retaining member can be adapted to carry a lens or other part which snap-fits into an annular recess formed by the retaining member.