Abstract: A substrate, such as a splice between two or more wires, a wire bundle or an electrical component, such as a suse, diode or transistor, is enclosed and sealed using a recoverable article comprising a polymeric sheet having an involuted curled section at one end and a sealant having a melt flow index has a specified relationship to the hot modulus of polymeric sheet. In an alternate embodiment, the sealant is a gel.

Abstract: A device (1) is described for disconnectably connecting cable wires to a contact plate (2). The contact plate contains a through opening (9) and, in use, one of the cable wires to be contacted is urged into contact with the edges of that opening (9). The cable wire is moved by a thrust piece (3) which also contains a through opening (24) and which is moved relative to the through opening (9) in the contact plate by means of a screw element.

Abstract: An arrangement for enclosing a branch-off between two or more cables (11,12) comprises a dimensionally recoverable sleeve (1) which can surround the branch-off and a clip (6) having a pair of legs (8) that can be positioned about opposed walls of the sleeve to divide the sleeve into channels for the cables. The sleeve has one or more transversely extending ribs at its end and the clip has a profile, e.g. being provided with protuberances 9, such that it can be pushed onto the end of the sleeve and can be retained thereon by engagement of the rib(s).

Abstract: A DC to DC switch mode power supply for a service subscriber interface unit of a fiber optic network includes a source of DC primary power, a main DC to DC switched mode power supply connected to the source of DC primary power and including switching circuitry and rectifier circuitry for supplying DC operating power to the service subscriber interface unit including central office battery power to at least one subscriber loop connected thereto, and a ringing voltage DC to AC switched mode generator connected to the source of DC primary power and including switching circuitry and synchronous rectification circuitry for generating ringing ringing voltage approximating a sine wave supplied as a reference to the synchronous rectification circuitry. A Johnson counter and resistor capacitor network is preferably employed to convert a reference ringing square wave into a sine wave.

Abstract: A predistortion circuit reduces composite second order intermodulation distortion products inherently generated by a laser diode. A radio frequency signal is split into a primary and secondary signal, and the secondary signal is amplified by an amplifier biased at a starvation current level so as to produce intermodulation distortion products having an amplitude relatively large compared to an amplitude of a fundamental generated by the amplifier. The amplitude and phase of composite second order intermodulation distortion products generated by the amplifier are adjusted so as to substantially match those inherently generated by the laser diode by the primary electrical signal, with the products being about 180.degree. out of phase relative to those generated by the laser in response to the primary signal.

Abstract: A method and apparatus implementing the method are provided for controlling optical power output level of a laser diode modulated during a burst mode interval by digital data transitions within a shared logical bus optical communications network and over a predetermined thermal gradient. The method comprises the steps of: optically monitoring a component of the optical output power of the laser diode during each burst mode interval and converting the component into a control signal, establishing a reference signal and comparing the control signal with the established reference signal and for providing a logical condition from said comparison, generating a strobe signal from information related in time to the burst mode interval, storing the logical condition upon receipt of the strobe signal, integrating the stored logical condition over a time period to provide an integrated control signal, and regulating current flow through the laser diode in accordance with the integrated control signal.

Abstract: A number of arrangements for protecting an electrical circuit from an electrical overcurrent are disclosed. In the arrangements the base or gate of a switching transistor (4, 101, 161, 222, 401) is held in a voltage divider, one arm of which comprises a control transistor (6, 102, 162, 222, 404) whose base or gate is itself held in a voltage divider. When an overcurrent is experienced the control transistor switches on causing the switching transistor to turn off. The arrangement may include a shunt switching circuit to shunt the overcurrent across the load. It may include a resetting circuit that will attempt to reset the switching circuit after the overcurrent has been experienced. In one embodiment the arrangement includes means such as a battery, dc--dc voltage converter or Seebeck device in order to reduce or eliminate any initial voltage drop across the switching circuit.

Abstract: A method of enclosing a substrate within a heat-shrinkable sleeve, which comprises the steps of:a) attaching to the substrate a slideway;b) attaching to the slideway a clip having at least two legs;c) positioning a heat-shrinkable sleeve around the substrate;d) sliding the clip by means of the slideway and with respect to the substrate such that at least one portion of the sleeve becomes positioned between the legs of the clip, ande) causing heat-shrinkage of the sleeve.

Abstract: A composition which contains 35 to 85% by weight of a copolymer of tetrafluoroethylene and hexafluoropropylene (FEP), 10 to 60% by weight of a copolymer of tetrafluoroethylene and perfluoropropylvinyl ether (PFA), and 5 to 60% by weight of melt-processable polytetrafluoroethylene (PTFE). The composition is particularly suitable for use as an insulating material on a substrate such as a resistive element in a conductive polymer heating cable. The composition has good physical properties, low creep, and low secondary crystallization, and exhibits little stress-cracking when exposed to elevated temperatures.

Abstract: A telecommunications closure (1) includes a pressure clamp (21) for sealingly clamping mating parts (47, 48) of the closure together so as to form a water tight seal. The clamp member requires no tools during installation and creates no uncertainty as to the generation of appropriate clamp pressure on a sealing O-ring when installed. The pressure clamp includes an over-center latch which is rotatable between a first unlatched position and a second latched position, a clamping pressure generated by the latch increasing to a maximum value as the rotatable latch is moved from its first position to an intermediate position between the first and second positions and then decreases from this maximum value as the latch is moved from the intermediate position to the second position so as to generate a predetermined appropriate clamping pressure when in its second position so as to appropriately compress the O-ring disposed within a groove between the closure parts at their mating area.

Abstract: A method of environmentally protecting an elongate substrate with a cover and a sealing means comprising a sealing material having an elongation of at least 100% and a compression set at 70.degree. C. of less than 30%, which comprises positioning the sealing means around a portion of the substrate and surrounding the substrate with the cover such that the sealing material provides a seal between the cover and the substrate.

Abstract: An apparatus and method for uniformly irradiating a strand of plastic material by twisting the strand as it is advanced in a plurality of paths transverse to an electron beam. A set of pinch rolls are positioned on opposites ends of the electron beam generator to advance and twist the strand. Lift cams periodically release the twist on the strand at positions of maximum twist by forcing the pinch rolls apart. Each set of pinch rolls includes upper and lower rolls adjacent a medial roll which, in turn, is driven in alternating axial directions to impart twist to the strand. The medial rolls are driven in alternating axial directions by a cammed surface thereon and a cam follower and synchronized to move 180.degree. out of phase from each other. A series of three spaced apart idler rolls are also provided to form a tandem figure-eight pattern in side view for the strand to compensate for reel set in the strand.

Abstract: A device for forming a solder connection between a plurality of electrical conductors, comprises a hollow, dimensionally heat-recoverable sleeve 1 formed for example from polyvinylidine fluoride, the sleeve having one end that is open to allow the insertion of the electrical conductors therein, and another end that is closed by a substantially spherical sealing insert.

Abstract: The cover and base of the enclosure of the assembly are releasably connected by latches and flanges integral with the cover and base. A mounting bracket facilitates mounting of the assembly upon a telephone pole or other exposed static structure. Vertically spaced upper and lower cable strain-relieving members underlie each cable passageway of the base of the enclosure. Each strain-relieving member is of generally u-shaped configuration. The open ends of the upper and lower strain-relieving members face in different directions. Each pair of the strain-relieving members collectively extends about the entire circumference of a cable engaged thereby.

Abstract: A liquid crystal projection display, having (a) a light source for producing light of at least two different primary colors; (b) an imaging element corresponding to each primary color light produced by the light source, each imaging element comprising plural pixel elements, each pixel element comprising liquid crystal composition dispersed in plural volumes in a containment medium and being independently addressable to primarily scatter light incident thereon in the absence of a sufficient electric field and to primarily transmit light incident thereon in the presence of a sufficient electric field; and (c) a lens for projecting light transmitted by each imaging element onto a screen; the liquid crystal composition in the pixel elements of the imaging element corresponding to the primary color light of longest wavelength including a pleochroic dye of a color complementary to the primary color light of longest wavelength, which pleochroic dye preferentially absorbs incident light which has not been scattered b

Abstract: A circuit protection device in which a PTC element made from a PTC composition includes or has at a boundary thereof a mechanical stress riser. The device will be tripped by, and provide reversible protection against, a first set of fault conditions, and will also provide protection at least one time against a second, more severe, set of fault conditions which cause physical disruption of the device and which cause the device to have a substantially infinite resistance. Devices of the invention are useful in protecting against relatively high voltages.

Abstract: An assembly capable of sealing an elongate substrate that is curved or angled along its length, which has a heat-shrinkable wraparound sleeve (1) having closure rails (3) adjacent opposing longitudinal edges thereof which can be held together by positioning a closure member thereover to maintain the sleeve in the wrapped-around configuration during heat-shrinkage and the closure member, which comprises an elongate channel (7) of sheet material substantially C-shaped in transverse cross-section having transverse first and second slits (9, 10) therein that extend substantially entirely across its width, respective first and second slits extending through each longitudinal edge, and giving the channel flexibility in two mutually perpendicular planes.

Abstract: An electrical device, particularly a self-regulating strip heater, has improved thermal efficiency, good mechanical properties, and acceptable resistance to water penetration when an outer insulating layer is applied in a way that it penetrates the interstices of a braid surrounding the heater. Appropriate penetration may be achieved by pressure-extruding the outer jacket over the braid.

Abstract: A high voltage insulator has a polymeric core that forms a mechanical strength member and an outer covering of a heat-shrinkable polymeric tube that is electrically insulating and non-tracking and that has sheds on its outer surface.

Abstract: A system is provided for firmly attaching a coaxial cable terminus to a standard connection jack in such a way that the connection point is effectively shielded from tampering by individuals and is effectively sealed from degrading elements in the atmosphere. The system includes a jack attachment member having a collet structure, a swagging shell which slips over the collet structure to accomplish a firm connection with the jack and a locking shroud which surrounds the swagging cylinder so as to make it difficult to de-attach and/or re-attach the cable terminus to the jack without special tooling. Such special tooling, however, is simple and inexpensive for authorized service technicians, thereby making the system at once relatively secure from tampering and atmospheric degradation and simple and inexpensive to install and maintain. Furthermore, the system can be retrofitted into existing coaxial cable equipment, using standard coaxial cable connection jacks.