Abstract: The present invention includes a contact block for a safety switch that has a support structure and a pair of electrical contacts that are fixed in position on the support structure. The contact block includes a contact block plunger provided with a bridging contact. The bridging contact extends through the contact block plunger, from one side to another, and protrudes from the sides of the contact block plunger. The contact block plunger is moveable in-between the fixed pair of electrical contacts to move the bridging contacts into and out of contact with the fixed pair of electrical contacts. A contact block guide extends along the support structure and between the pair of fixed electrical contacts and cooperates with the contact block plunger such that the contact block plunger is restricted to movement along the contact block guide.

Abstract: There is provided a safety switch having a housing configured to receive a removable key, and a mechanism arranged to be operated when the key is moved from an engaged position to a partially disengaged position, the mechanism being arranged to cause a signal to pass to a separate apparatus, wherein the safety switch further comprises a lock which is controlled by the separate apparatus and is arranged to prevent the key from being fully disengaged from the safety switch until a signal has been received in response from the separate apparatus.

Abstract: A safety switch plunger includes a moveable conductor which extends transversely through the plunger and protrudes from opposite sides of the plunger. The plunger is provided with a structure that is positionally fixed on the plunger. The structure is positioned such that it is arranged to come into physical contact with and affect the movement of the moveable conductor when the moveable conductor and plunger are moved relative to one another thereby providing a fail-to-safe safety switch.

Abstract: A safety switch that includes a locking mechanism having a rod locking element that is located adjacent to a rod and engageable with the rod to lock the rod in position relative to a housing. The safety switch locking mechanism includes a locking member that is moveable relative to the housing in response to a difference in inertia between the locking member and the housing when a force is applied to the housing. The locking member is arranged to inhibit disengagement of the rod-locking element from the rod when the force is applied to the housing.

Abstract: The present invention includes a contact block for a safety switch that has a support structure and a pair of electrical contacts that are fixed in position on the support structure. The contact block includes a contact block plunger provided with a bridging contact. The bridging contact extends through the contact block plunger, from one side to another, and protrudes from the sides of the contact block plunger. The contact block plunger is moveable in-between the fixed pair of electrical contacts to move the bridging contacts into and out of contact with the fixed pair of electrical contacts. A contact block guide extends along the support structure and between the pair of fixed electrical contacts and cooperates with the contact block plunger such that the contact block plunger is restricted to movement along the contact block guide.

Abstract: There is provided a safety switch having a housing configured to receive a removable key, and a mechanism arranged to be operated when the key is moved from an engaged position to a partially disengaged position, the mechanism being arranged to cause a signal to pass to a separate apparatus, wherein the safety switch further comprises a lock which is controlled by the separate apparatus and is arranged to prevent the key from being fully disengaged from the safety switch until a signal has been received in response from the separate apparatus.

Abstract: A safety switch plunger includes a moveable conductor which extends transversely through the plunger and protrudes from opposite sides of the plunger. The plunger is provided with a structure that is positionally fixed on the plunger. The structure is positioned such that it is arranged to come into physical contact with and affect the movement of the moveable conductor when the moveable conductor and plunger are moved relative to one another thereby providing a fail-to-safe safety switch.

Abstract: A safety switch that includes a locking mechanism having a rod locking element that is located adjacent to a rod and engageable with the rod to lock the rod in position relative to a housing. The safety switch locking mechanism includes a locking member that is moveable relative to the housing in response to a difference in inertia between the locking member and the housing when a force is applied to the housing. The locking member is arranged to inhibit disengagement of the rod-locking element from the rod when the force is applied to the housing.

Abstract: Method and apparatus are disclosed for establishing a wideband communication facility from a plurality of narrow bandwidth channels through a switched communications network from a first to a second terminal in response to a call from the first terminal indicating a customer-selected bandwidth for the wideband facility. Apparatus is also disclosed for establishing a wideband communication path through an illustrative switching system interconnecting groups of narrowband time division multiplexed channels established for the wideband facility. The path has a bandwidth greater than any of the TDM channels. Additional buffer memories and memory control arrangements are added to the initial and final stages of a time-space-time switching network to prevent any of the time slot data of a given time frame from being delayed and included in another time frame.

Abstract: Apparatus and method are disclosed for overriding a fraud control feature utilized by a switching system to disable communications over a unidirectional path serving a call until answer supervision is returned for the call. The switching system includes a fraud control unit which inserts idle code into the unidirectional transmit path serving the call and disables communications on the path from a calling to a called line. However, normal call progress signals are allowed to pass on the receive path from the called to the calling line. The fraud control unit includes an idle code generator for generating the idle code and a selector for inserting either the idle code from the generator or the communications on the transmit path from the caller. The selector is controlled by a control unit under the control of the central processor of the switching system.

Abstract: A wideband communication facility is established via a switched network between calling and called terminals. The wideband facility comprises a number of segments, each segment including a plurality of narrowband time division multiplex channels having a total bandwidth at least equal to the bandwidth of the wideband facility. A switching system of the network interconnects the wideband facility segments and assembles all the data received in a given time frame from one segment into the single time frame for transmission to another facility segment. Additional buffer memories are added to the initial and final stages of a time-space-time switching network to insure that all the data received in one time frame from a given facility segment is assembled only into the same time farme for transmission on an outgoing facility segment.

Abstract: A telephone switching office having a plurality of meet-me conference bridging systems is disclosed. An access code is assigned to each conference, and at an agreed upon time, all conferees for a conference dial the same access code. The switching office allocates a bridging system in response to the first call to arrive at the office. In the event more than one call for the same conference arrives at the host office concurrently, the processing of all but one call is delayed until an idle bridging system is connected to that one call. The delayed calls, and any future calls to the conference are then steered to the same bridging system.

Abstract: A processor controlled conference arrangement is connected to a host switching system. The availability of conference resources (e.g., ports, registers, etc.) and processor real time capacity is measured before a call is forwarded to the conference arrangement.

Abstract: A telephone switching office is disclosed having a public announcement system wherein new announcements can be recorded or priorly recorded announcements can be updated via the telephone network. The producer dials a number associated with the announcement to be updated and transmits the update announcement to the office. In order to verify the announcement with an authorized party, the switching office calls the producer at a preassigned station and plays back the update announcement. If the producer disconnects before the playback is completed, the playback announcement is aborted; otherwise, the new version is made active and the former announcement is removed from service.