Abstract: A buzzer comprises a vibrator unit including a diaphragm which is supported within a housing, and a drive unit including a coil assembly which electromagnetically excites the vibrator unit. The coil assembly includes a bobbin of a non-magnetic and non-conductive material and having flanges at its both axial ends, and a winding disposed on the bobbin. The drive unit is supported by at least one of the flanges and is provided with a plurality of rigid electrical leads which project to the exterior of the housing.

Abstract: A buzzer comprises a vibration unit, an electromagnet transducer for applying an electromagnetic excitation to the unit, and an electronic oscillation circuit for driving the transducer. The oscillation circuit includes a group of electrical components which constitute a blocking oscillator together with the coil assembly of the transducer and which are contained on a bipolar integrated circuit module. The module is mounted on the coil bobbin of the transducer.

Abstract: This invention relates to a contactless buzzer unit wherein audible signals are delivered by mechanical blows of a resonator membrane by an electromagnetically driven vibrator fed from an electronic circuit with oscillating voltage pulses. A base section is provided by an electromagnetic drive unit having an iron core and a drive coil fixedly mounted on a base plate, while a casing section is provided by an audio-signaling unit including the resonator membrane, a spacer and a vibrator assembled together and attached to a case member. Both these sections are assembled together and to the case member molded with plastic material into one piece which is provided with stud posts extending from two precisely formed and mutually parallel planes formed on the case member and serving for the assembly of these sections as guiding, positioning and fixing means.

Abstract: A blocking oscillator for driving the armature of a buzzer comprises a transistor which is stabilized against changes in ambient temperature and fluctuations of a supply voltage. A core is provided for magnetically driving the armature, and carries thereon a drive coil which induces a regularly varying electromagnetic field therein as well as a control coil which is connected in feedback relationship with the drive coil. The drive coil forms together with the collector emitter path of the transistor a series circuit, which is connected with a power supply and which is shunted by another series circuit comprising a resistor, the control coil and a diode and which is also connected across the power supply. The base of the transistor is connected with the junction between the resistor and the control coil. The control coil is shunted by a forwardly poled diode.

Abstract: A card reader is provided which includes backup means for urging a coded region of a magnetic card against a transducer in a proper orientation and with a proper pressure. The backup means is disposed opposite to the transducer on the other side of a card guide slot, and includes a ball head having a spherical surface which is normally biased by a spring to its operative position extending into the guide slot in which the gap defined between the transducer and the ball head is less than the thickness of a card. As the card is moved through the guide slot, the ball head is moved by the card away from the transducer against the resilience of the spring, but provides a single point backup of the card against the transducer before such movement in the opposite direction occurs.

Abstract: This invention relates to contactless buzzer unit wherein audible signals are delivered by mechanical blows of a resonator membrane by an electromagnetically driven vibrator fed from an electronic circuit with oscillating voltage pulses. A base section is provided by an electromagnetic drive unit having an iron core and a drive coil fixedly mounted on a base plate, while a casing section is provided by an audio-signaling unit including the resonator membrane, a spacer and a vibrator assembled together and attached to a case member. Both these sections are assembled together and to the case member molded with plastic material into one piece which is provided with stud posts extending from two precisely formed, precisely and mutually, precisely parallel planes formed on the case member and serving for the assembly of these sections as guiding, positioning and fixing means.