A tapered end fitting for a glass fiber rod applies a substantially uniform stress to the portion of the rod falling within the end fitting, and thus can withstand tensile loadings up to the tensile strength of the rod itself. A uniform stress distribution is achieved by designing the end fitting so that it subjects to the rod to a uniform volume strain. This, in turn, is achieved either by properly tapering the inner surface of the end fitting outer jacket, or by properly choosing the characteristics of the collect which fills the space between the rod and the outer jacket of the end fitting.
For fixing metal sheaths on glass fiber reinforced plastic rods, which rods are used, for example, in composite insulators: the sheath is in a number of sections in a longitudinal array; there is an abutment inside the sheath at each sheath section, there is a shoulder piece on the outside of the rod inside each sheath section; the abutment in a sheath section is at one longitudinal side of the respective shoulder piece in that sheath section; elastic and compliant buffer means, such as springs, or the like, are placed between the abutment and its shoulder piece; the compliance of the buffer means increases toward one end of the arrangement to compensate for the different rates of expansion of the sheath and the rod; other embodiments all have appropriate buffer means in each sheath section, which buffer means increase in compliance moving toward the end of the sheath through which the rod exits.
A composite sucker rod to be formed into a rod string for an oil well is made by placing a coupler unit having a box end on each end of the rod. The coupler unit has a bore extending the full length of the coupler unit. For fabrication, the coupling unit is telescoped over the rod and a conic expansion portion formed on the end of the rod so that the conic expansion portion may be jammed into a tapered bore on the rod. The conic expansion portion is formed when the end is clear of the coupling unit so that it may be well bonded to the rod by precise application of adhesive, heat, and pressure. By using box end couplings on the rod and pin end couplings on coupling units between the rod it is possible to have a smaller overall outside diameter for any given strength of coupling unit.
A metal fitting for a composite electrical insulator (1) including a plastic rod (2), e.g., an FRP rod. The metal fitting (4) includes a radially inwardly deformable sleeve portion having a bore (5) into which an end portion of the rod (1) can be inserted for fixedly securing the metal fitting (4) to the rod (1). The bore (5) in the metal fitting (4) has an inner surface which is formed with fine protrusions (7). These protrusions (7) provide a satisfactory resistivity to the tensile force applied to the insulator (1), to thereby effectively prevent withdrawal of the rod (2) from the metal fitting (4) when it is in use.
A process and devices which allow the formation of a molded termination at some point on a cable. A shell is used to surround and hold the strands to be terminated. This shell is made from a first material. The strands are bonded to the shell, typically using potting compound. A second material is then molded over the shell to form a complete termination. In another embodiment, the shell is actually created from the potting compound itself by allowing the potting compound to harden in a mold.
A cable termination arrangement includes a tapered socket body and a mating plug covered with a sleeve of malleable material. Cable strands are inserted and spread out inside of the socket. The plug and sleeve are pushed into the socket for forcing the strands into the sleeve. When a tensile force is applied to the cable, slippage between the cable and the socket is zero.
