Abstract: The present invention relates to accelerometer assemblies for implantable medical devices such as pacemakers, IPGs, PCDs, defibrillators, ICDs and the like. The accelerometer assembly of the present invention comprises a beam that deflects in response to being subjected to an externally provided force. Deflection of the beam generates a voltage in a piezoelectric material disposed in the assembly. At least one stop is provided to limit the vertical range of motion through which the beam may deflect to prevent failure, fracturing or breakage of the beam resulting from excessive deflection of the beam that might otherwise occur were the stop not present.

Abstract: Disclosed are method and apparatus for creating a cantilever accelerometer beam by mechanically forming an accelerometer from a piezoelectric substrate. The inherent structure of the accelerometer provides a means for employing surface mount technology (SMT), or a protective package may be utilized to couple the accelerometer to the hybrid circuit within an implantable pacemaker. The sensor's structure is defined by three members. The first and second members are used to couple the sensor to the hybrid circuit and the third member defines the cantilever accelerometer beam, which generates an electrical output signal indicative of a patient's activity.

Abstract: A ratchet wrench imparts rotational movement to a relatively large workpiece such as the stem of a water main valve or a fire hydrant. The wrench includes an annular driver member, a housing having an elongated recess, a pawl element and a bias element. The annular driver member is adapted to detachably engage the workpiece and includes a plurality of driver teeth disposed circumferentially around its outer periphery. The housing receives the annular driver member so that rotational movement can be imparted to it within the housing and the handle structure extends from the housing to provide mechanical advantage for imparting the rotational movement. The elongated recess extends into the housing along a longitudinal access. The elongated recess is positioned with respect to an imaginary line tangent to a selected radius of the annular driver member such that the longitudinal axis is disposed substantially parallel to or coextensive with the selected radius.