Ultrasonic equipment for generating section images

In ultrasonic equipment for examinations using section displays, comprising

• a pivoted carrier,
• sound transducer head means carried by, and fixed to, said carrier and operable to transmit an ultrasonic sound beam into a section surface of an object to be examined and to derive echo signals from echoes orignated in said section surface in response to said sound beam,
• a scanning mechanism including a rotary reversible motor and a transmission operable by said motor to impart to said carrier an oscillating pivotal motion through an angle of swing whereby said sound beam is caused to scan a sector of said section surface, said transmission consisting of a crank mechanism for transforming a rotational motion of said motor into said oscillating angular motion and comprises an eccentric member adapted to be rotated by said motor about an axis of rotation, a connecting rod pivoted to said eccentric member on a first pivotal axis spaced from said axis of rotation, and a bearing member disposed adjacent to said axis of rotation and pivoted to said carrier on a second pivotal axis which is transverse to said axis of rotation, said connecting rod being rotatably mounted in said bearing member, said carrier being pivoted on a third pivotal axis which intersects said axis of rotation, and said connecting rod being arranged so that, in response to a rotation of said eccentric member about said axis of rotation, said connecting rod describes a surface of an imaginary cone having an included angle that is equal to said angle of swing and imparts to said carrier a pivotal movement about said third pivotal axis through said angle of swing,
• a display unit comprising a fluorescent screen,
• display control means for causing said display unit to display on said fluorescent screen a section image in which each of said echo signals is displayed at a location which is geometrically coordinated with the location at which the corresponding echo has originated in said section surface, and
• adjusting means for adjusting said angle of swing and the angular width of said section image, said adjusting means being adapted to alter the ratio of the effective length of said connecting rod between said first and second pivotal axes to the distance from said axis of rotation to said first pivotal axis, whereby said angle of swing is altered as well as the transmission ratio of said crank mechanism, said adjusting means being arranged to adjust said ratio to a first value in response to an initiation of a rotation of said motor in a first sense and to adjust said ratio to a second value in response to an initiation of a rotation of said motor in a second sense.