Abstract: A waterproof splice for use in connecting two multiconductor electric cables having jackets of different insulation material and a method of making the splice are disclosed. The splice consists of a mechanical electrical connection between the conductors, a mechanical bond formed on the insulation of one of the conductors and a sheath of insulation material molded over the splice and adjacent cables. The sheath bonds with the jacket of one cable and the mechanical bond formed on the insulation of the other cable. The mechanical bond is a seal ring of elastomeric material that is compressed between glands to move the seal ring into sealing engagement with the conductor. The disclosed splice is both strong and waterproof in spite of the poor bonding characteristics between the two different insulation materials on the two conductors. The splice is appropriate for cables having surface, subsurface and underwater applications and is specifically designed for use in conducting seismic surveying operations.

Abstract: An improved reduced distortion spring spider for geophones is disclosed that has the desired ratio of spurious resonant frequency to the natural frequency of the geophone and can absorb the sharp lateral forces imposed on the geophone during destructive testing and field usage.

Abstract: A geophone is disclosed that has a cylindrical housing closed at one end by a bottom and the other end by a top. A magnet assembly of a rare earth magnet with pole pieces at each end of the magnet is centrally mounted in the housing providing an annular space between the magnet assembly and the housing. A coil form is located in the annular space. Springs support the coil form for axial movement relative to the magnet assembly along the longitudinal axis of the housing. The rare earth magnet produces a magnetic field sufficiently strong that the pole pieces can be made longer than the coils on the coil form thereby provided a uniform magnetic field in which the coils move thereby reducing the amount of harmonic distortion produced by the geophone.

Abstract: A geophone is disclosed that has a cylindrical housing closed at one end by a bottom and the other end by a top. A magnet assembly with pole pieces at each end of the magnet is centrally mounted in the housing providing an annular space between the magnet assembly and the housing. A coil form is located in the annular space. Springs support the coil form for axial movement relative to the magnet assembly along the longitudinal axis of the housing. Washers are included on the upper and lower sides of each of the springs to enhance the life span of the springs by reducing the damage caused by torsional forces experienced by the springs during normal operation and rough handling. Also incorporated in the geophone are resilient members mounted between the coil form and the housing to prevent the coil form from directly hitting the housing and thereby reduce the amount of frequency shift experienced by the geophone over its life span.

Abstract: A heat shrinkable covering in the form of a sheet which is heat shrinkable in a longitudinal direction, and a stiffening member connected at each of two longitudinally spaced transversely extending superimposable zones of the sheet. One stiffening member has holes and the other studs in the form of arm portions which are insertable through the holes to secure the stiffening members together. The arm portions can be flattened down onto the outside of the covering to retain the stiffening members together while reducing risk of the studs interfering with items such as cables adjacent the covered article. Preferably the studs have a resiliently compressible head portion which snap fits into holes formed through the sheet adjacent the holes in the stiffening member to facilitate locating the overlapped zones of the sheet relative to one another. In use, the sheet is wrapped around an article, the stiffening members are engaged together, and the sheet is then heat shrunk.

Abstract: A heat shrinkable covering for an article, such as a pipe, comprises a heat shrinkable material in the form of a flexible sheet which is wrapped around the article so that its ends overlap. The overlapping end portions are bonded together by means of a hold-down adhesive, preferably a shear-resistant adhesive, leaving an adhesive-free region at the interface. Heat is applied externally to the overlapping end portions so as to effect a fusion bond at the adhesive-free region of the interface, and the sheet is heat-shrunk onto the article in known manner. The covering offers the advantages and convenience of application common to conventional wrap-around sleeves, while having the intrinsic strength properties of a seamless tubular sleeve.