Abstract: An elongated line protector has a series of base modules for plug-in reception of a series of arrester modules, carbon or gas tube type as may be selected. Along opposed sides of the base modules are recesses for slide-on attachment of terminal modules each having a row of terminals, such as binding posts, connector clips, etc. for connections to telephone lines to be protected. Several groups of terminal modules may be assembled with each other side-by-side on each of the opposed base module sides depending upon the number of groups and styles of terminals desired. Correct electrical connections between the terminals and the arresters are established through the protector upon assembly by conductors including ground and line busses.

Abstract: A line protector for protecting telephone lines and the like from over-voltage or over-current conditions includes a primary arrester element and a secondary arrester element that provides back-up protection upon a fail open of the primary arrester element. The primary arrester comprises a gas tube having spaced electrodes to form an arc gap therebetween. The secondary arrester includes a pair of electrodes axially aligned with the gas tube and separated by an insulating spacer to provide an air gap therebetween. The air gap of the secondary arrester is maintained at a predetermined spacing such that the breakdown voltage thereof is greater than the rated breakdown voltage across the arc gap of the gas tube but less than the breakdown voltage across said arc gap should the gas tube fail open as by being vented to atmosphere.

Abstract: A surge arrester of the gas tube type for protecting telephone lines has a primary arc gap and a secondary arc gap electrically coupled in parallel. The primary arc gap is wider than the secondary arc gap and both arc gap are exposed to the inert gaseous medium of the arrester. The gas pressure and the width of the gaps are such that the breakdown voltage of the primary arc gap is less than the breakdown voltage of the secondary arc gap so that in normal operation the arrester discharges through the primary arc gap. However, if the inert gas leaks from the tube and becomes replaced with air at atmospheric pressure, the arrester will discharge through the secondary arc gap to provide a backup protection for the line.

Abstract: A surge arrester for providing overvoltage protection for communications lines and the like comprises a pair of electrodes having opposed faces to define the arc gap therebetween. The opposed faces include a pair of facing annular, concentric ridges, a valley opening radially inside of the annular ridges and an annular space or opening radially outside of the annular ridges. The valley opening and annular opening extend axially of the ridges to provide a maximum of relief or cavity space for particles that erupt from the electrodes during discharge regardless of the polarity of the electrodes. The cavity space is used for venting erupted particles away from the arc gap.

Abstract: An electrical connector is disclosed comprising a connector block provided with an opening therethrough and an electrically conductive terminal having a portion thereof projecting outwardly of the block at the opening. The electrical terminal is also provided with means in its outwardly projecting part for terminating an electrical conductor thereon. The part of the terminal in the block has opposed side faces having at least two opposed bosses formed thereon for retaining the terminal in the block.

Abstract: A gas-filled surge arrester includes a pair of electrodes extending inwardly of an insulating spacer. The electrodes have end faces which are aligned oppositely within the insulator to define an arc or discharge gap therebetween. Each of the electrodes includes at least one cavity formed in the end face thereof adjacent and extending away from the discharge gap. The cavities are lined with a substance of relatively high electron emission ability.

Abstract: A terminal block comprises clip type terminals which snap fit into the block and project outwardly from opposite faces of the block. The terminals are disposed in an array consisting of a number of rows and columns. At opposite margins of the terminal block are fanning strips for receiving the wires that are joined to the terminals. The block has recesses for the wires and the recesses are progressively deeper as they extend from the center of the block toward the fanning strips, thereby avoiding a buildup of conductors at the terminals that are adjacent to the fanning strips. The fanning strips also have resilient fingers that retain the wires in the various slots of the fanning strip.

Abstract: A line protector for communications circuits comprises a gas tube having external contact surfaces for connections to communication lines and to ground. A conductive member is proximate to the contact surfaces that are associated with the communication lines. A dielectric substance interposed between the conductive member and the last-mentioned contact surfaces melts upon overheating of the protector resulting from the excessive line current. The conductive member, due to its resiliency, engages the subjacent contact surface or surfaces thereby resulting in a direct short circuit between the protected line and ground. A shield over at least part of the gas tube in the region of the conductive member prevents potting compound or foreign matter from obstructing the function of the conductive member.

Abstract: A telephone distribution frame connector assembly comprises a connector block with terminals for receiving plug-in type overload protector modules. Incoming line pairs are connected through a cable stub to terminals on the block. Furthermore, terminals on the block are connected to inside central office equipment, the connections being through the overload protector modules. A test field is provided for testing the lines. The test field and the terminals for central office connection are mounted in various novel ways to effect a compact arrangement.

Abstract: A surge arrester for protecting telephone lines and the like from overvoltage has opposed carbon electrodes separated by an insulating spacer that houses one of the electrodes and provides a means for spacing the electrodes to define the arc gap therebetween. The other electrode has one round plateau with a flat end surface that defines one side of the gap. The plateau is surrounded by a valley structure which provides a maximum of relief or cavity space for carbon particles that erupt from the electrodes during discharge. The cavity space is used for venting erupted particles across the end of the spacer and thereby provides an increase in the surge life of the arrester.

Abstract: A concrete form assembly comprises spaced apart form members that are retained in position during concrete pouring by an arrangement that includes spacer elements, plastic tie rods, and anchors. The anchors are on the outsides of the forms and grip the tie rods. Each anchor comprises a tapered jaw cluster in a tapered shell so arranged that outward forces applied to the forms due to concrete being poured therebetween increases the grip of the anchors on the tie rods to retain the forms at the established spacing.

Abstract: A modular distribution frame assembly for carrying telephone line terminal and protection blocks in a substantially complete factory-prewired condition. The modular distribution frame has a base for securing to a floor support and a telescopic upper end for securing to an overhead support. The distribution frame assembly has a main vertical open column for receiving the plurality of jumper wires which are used to interconnect incoming subscriber or trunk lines with central office distribution lines. Incoming lines can be introduced into a secondary vertical open column located next to the main open (jumper) column for connection either directly to the appropriate protection or line terminal blocks or to a multiposition connector which has its mating half mounted to and electrically connected to the appropriate protector or line terminal blocks.

Abstract: A tone detector is connected or otherwise associated with an outgoing telephone trunk line adapted to be included in a toll path. One or more frequency or tone signals are sent over the trunk line for signaling and control during a toll call. If these tone signals appear at a point on the trunk line where the toll call remains under the control of d.c. signals, they must be fraudulent since there is no preceding equipment which is adapted to send valid tone signals. Therefore, a tone detector may be connected to that point in order to drop or otherwise block any calls during which the fraudulent tone signals appear. The toll fraud eliminator is particularly -- but not exclusively -- useful for preventing employment of a "blue box" during toll calls. The tone detector uses two multivibrators which operate at an upper and a lower threshold frequency respectively.

Abstract: A line protector includes a body having first and second end terminals and an intermediate terminal for connection to a ground potential. End caps are mounted on the end terminals and have peripheral edges maintained spaced from the intermediate terminal by means of a displaceable element responsive to excessive currents in the line being protected. High currents will cause the end caps to move toward the intermediate terminal and provide a short circuit therewith to ground to protect telephone equipment connected thereto. The intermediate terminal is mounted in a clip which has centering means formed therein to maintain the mechanical and electrical spacing of the intermediate terminal with respect to the end caps equal to one another. The protector assembly is mounted with a standard housing and base structure to be interchangeable with existing central office plug-in protectors.

Abstract: A terminal block assembly has a dielectric body and a plurality of terminals therein. The terminals are retained by a plate that engages the body of the terminal block through a slide. Spring tabs on the plate engage recesses in the body to prevent sliding movement of the plate in one direction. A bracket for removably snap-fitting engagement with the terminal block is adapted to be mounted on a supporting surface. With the block removed, the bracket presents a channel into which a cable bundle may be positioned without obstruction. The terminal block provides a closure for the open side of the channel.

Abstract: Post-tensioning apparatus for cast concrete comprises dead end and live end anchors adjacent to the casting forms for gripping and post-tensioning reinforcing tendons. A group of dead end anchors are preassembled with a flexible plastic strip, and likewise a group of live end anchors are preassembled with a flexible plastic strip. The strips permit preset spacing of the anchors so that each assembly of anchors can be secured to the associated form with accurate spacing provided for respective dead and live anchors in the setup.

Abstract: The embodiment of the invention disclosed herein is directed to a gas tube tester which provides a pair of terminals for connection to the external electrodes of a cold cathode gas discharge tube. The tester includes one circuit for applying a progressively increasing voltage across the discharge tube so that the breakover voltage of the tube can be determined, this breakover voltage being registered on a meter. A second circuit is provided for testing the leakage current of the gas discharge tube within predetermined limits. A leakage current corresponding to a one megohm internal resistance is sufficient to render conductive a programmable silicon controlled rectifier to give an indication of excessive leakage current.