Abstract: An improved chiropractic adjusting instrument is provided for use in spinal manipulative therapy and for exciting a human spine at preselected resettable frequencies within the range of its natural frequency. The improvement comprises a preloaded body contact thrust member.

Abstract: The invention is an electrically insulated steel railway cross tie for use with railway tracks using track circuit systems. The electrically insulated steel cross tie prevents the cross tie for shorting the track circuit systems. A method of manufacturing the electrically insulated steel cross tie is to transversely cut an uninsulated steel cross tie into separate elongated members. The elongated members are then re-joined end to end with an insulator member interposed between the elongated members. The insulator member prevents electrical current from being conducted from one elongated member to another elongated member. In the preferred embodiment end plates are welded to the cut ends of the elongated members and bolts are used to releasably join the elongated members together. The bolts are electrically insulated to prevent the bolts from conducting electrical current between the elongated members.