Abstract: An electromagnetic relay includes a first fixed terminal, a second fixed terminal, a movable contact piece, a case, a magnet, and a gas flow path. The first fixed terminal includes a first fixed contact. The second fixed terminal includes a second fixed contact. The movable contact piece includes a first movable contact and a second movable contact. The case includes an accommodation space where the first fixed contact, the second fixed contact, and the movable contact piece are accommodated, a gas inflow space separate from the accommodation space, and a side wall covering the accommodation space and the gas inflow space in a first direction. The magnet is disposed between the accommodation space and the gas inflow space. The gas flow path is disposed between the side wall of the case and the magnet and is configured to communicate the accommodation space with the gas inflow space.

Abstract: An electromagnetic relay includes a first fixed terminal including a first fixed contact, a second fixed terminal including a second fixed contact, a movable contact piece including first and second contacts, a drive device including a coil, a case, and a magnet. The case includes an accommodation space accommodating the first fixed contact, the second fixed contact, and the movable contact piece, and a first arc extension space at least partially disposed between the coil and the magnet. The magnet is disposed so as to overlap with the coil in a third direction orthogonal to the moving direction and a longitudinal direction of the movable contact piece. The magnet configured to extend a first arc generated between the first fixed contact and the first movable contact and a second arc generated between the second fixed contact and the second movable contact in the longitudinal direction of the movable contact piece.

Abstract: A memory module socket, including a first member extending between a first end and a second end of the socket, the second end of the socket opposite to the first end of the socket, the first member positioned along a first side of the socket, the first member including: a plurality of first contact pins, each of the first contact pins including a first contact point and a second contact point; a plurality of first resistive coatings connecting two or more of the first contact pins to define first groupings of contact pins; a plurality of first ribs separating each of the first groupings of first contact pins; wherein when the first contact pins are in a first position, the second contact points of the first contact pins are in contact with respective first resistive coatings to complete a termination to ground.

Abstract: An electromagnetic relay includes a case, a first fixed terminal including a first fixed contact, a second fixed terminal including a second fixed contact, a movable contact piece including first and second movable contacts, a first magnet, a gas flow path, and a partition member. The case includes an accommodation space and a side wall covering the accommodation space in a first direction. The accommodation space includes a first space where the first fixed contact is disposed and a second space where the second fixed contact is disposed. The first magnet configured to extend a first arc generated between the first fixed contact and the first movable contact in the first direction. The gas flow path is disposed between the side wall and the movable contact piece. The gas flow path includes an inlet communicating with the first space and an outlet communicating with the second space.

Abstract: An electromagnetic relay includes a first fixed terminal including a first fixed contact, a second fixed terminal including a second fixed contact, a movable contact piece, a case, a drive device, and a first magnet. The movable contact piece includes a first movable contact and a second movable contact. The case includes an accommodation space and a side wall covering the accommodation space in a first direction. The first magnet extends an arc generated between the first fixed contact and the first movable contact in a second direction opposite to the first direction. The first fixed terminal includes a first end. The first end of the first fixed terminal includes a tapered portion inclined in the second direction from the first fixed contact toward the first magnet and that at least partially overlaps with the first magnet when viewed from a moving direction of the movable contact piece.

Abstract: An electromagnetic relay includes: an exciting coil; a movable core driven by the exciting coil; a movable contactor having a first movable contact and a second movable contact to operate with the movable core; a first fixed terminal having a first fixed contact with which the first movable contact abuts when the movable contactor is moved by energizing the exciting coil; and a second fixed terminal having a second fixed contact with which the second movable contact abuts when the movable contactor is moved by energizing the exciting coil. An inclination angle of a central axis of the first movable contact with respect to a central axis of the first fixed contact and an inclination angle of a central axis of the second movable contact with respect to a central axis of the second fixed contact are inclined in opposite directions from each other.

Abstract: An electrical switchgear includes: a housing; at least one first contact mounted in the housing; at least one second contact translationally movable within the housing in a translational movement direction; a switchgear control mechanism having a first rotary element having a first rotation axis and a second rotary element having a second rotation axis; and a link element pivoted on one end thereof to the first rotary element and on an other end thereof to the at least one second contact. The first and the second rotation axes are arranged substantially perpendicular to each other. The second rotation axis is arranged essentially in parallel to the translational movement direction of the at least one second contact. The first and the second rotary elements engage such that a rotation of the second rotary element is transmitted to the first rotary element.

Abstract: A double breaker switch comprises a contact bridge connected to an actuator at a connection point, a first fixed contact, and a second fixed contact. The contact bridge includes a first bridge contact connected to the connection point by a first arm and a second bridge contact connected to the connection point by a second arm. The second arm is longer than the first arm. The first bridge contact electrically connects with the first fixed contact at a first contact point in a closed state of the double breaker switch. The second bridge contact electrically connects with the second fixed contact at a second contact point and a third contact point in the closed state of the double breaker switch.

Abstract: A power tool which contains a casing, a brushless motor (22) mounted inside the casing, a user actuated switch (38) mounted on the casing, and a circuit board (32) mounted inside the casing. The brushless motor (22) is adapted to drive one or more movable parts in the power tool. The circuit board (32) is mechanically connected to the brushless motor (22) and the switch (38) at the same time. As only a single, integrated circuit board (32) is configured in the power tool, the manufacturing cost is reduced and greater reliance and electrical safety can be achieved.

Abstract: A medium or high voltage switch including a moveable contact element and a stationary contact element is described. Therein, a moveable-contact guiding portion of the moveable contact element and a stationary-contact guiding portion of the stationary contact element are shaped for establishing a spherical-bearing-type mechanical connection between each other, thereby aligning a center of the moveable-contact guiding portion with a center of the stationary-contact guiding portion while allowing an angular flexion between the moveable and stationary contact elements. Furthermore, at least one of the stationary-contact guiding portion and the moveable-contact guiding portion is electrically insulating.

Abstract: Apparatus for allowing a welder to control the output power of a welding machine, and thus its arc power by applying force to a surface of a force sensing transducer assembly. The force sensing transducer assembly generates a force signal based upon the force applied, for example by reducing the resistance within the force sensing transducer assembly. A control interface module then receives the force signal and controls the welding machine power output based upon the force signal. The welder may set the range of force to change the arc power by setting a minimum amount of force to actuate the welding machine and a maximum force that increases the output power of the welding machine (force below the minimum does not actuate the welding machine and force above the maximum does not increase the welding machine power above a certain level).

Abstract: A handheld work apparatus has an electric motor for driving a tool. A function module is to be connected to a battery pack via electrical contacts, there being provided an electrical operating switch, for putting the electric motor into operation, which is coupled to an actuating element of the handheld work apparatus. The electric motor is put into operation upon a command of the operating switch, via a control unit. To constitute the function module, provision is made to dispose the electrical contacts, the control unit and the operating switch on a common carrier. The carrier has a first side that faces toward the battery pack, and at least one second side that faces away from the battery pack. The electrical contacts are provided on the first side of the carrier, while the operating switch is held on the second side of the carrier.

Abstract: A spring plate includes a central portion; an opening that is positioned at a center of the central portion; and a strip extending from a part of an inner edge of the opening that is positioned at the center of the central portion. The strip includes a first width that is positioned adjacent to the part of the inner edge of the opening and a second width that is positioned adjacent to an end of the strip. The first width of the strip is wider than the second width that is positioned adjacent to the end of the strip.

Abstract: The present invention relates to a ground terminal for an electronic device. The ground terminal comprises a ground cable connecting device, an electrical switch, an electrical conductor connecting the ground cable connecting device to the electrical switch. The ground terminal and its ground cable connecting device is configured so that the electrical switch is brought in to a first mode in response to an electrical wire being connected to the ground cable connecting device, the first mode being a mode in which the switch establish electrical conduction between an electrical circuit of the electronic device and the ground cable connecting device.

Abstract: A bypass switch provides a bypass path between a first terminal and a second terminal. The bypass switch includes: a first set of electrical contacts respectively connected to the first terminal and the second terminal; a second set of electrical contacts respectively connected to the first terminal and the second terminal; and a movable member.

Abstract: A contact arm for use in a circuit breaker is provided. The contact arm includes a tubular body that includes a conductive tube and defines a central longitudinal axis of the contact arm. The body has a first end configured for connection with a contact of the circuit breaker, and a second end configured for connection with a pole of the circuit breaker. The body defines a plurality of apertures extending therethrough from an outer surface of the body to an inner surface of the body.

Abstract: A switching device has a switching chamber; a plate-like switching element, which can be moved in the switching chamber along a linear movement axis (Z) between an ON position in which the switching element connects fixed contacts to one another, and an OFF position in which the switching element is at a distance from the fixed contacts; an actuator for linear movement of the switching element inside the switching chamber; and spring(s) which prestress the switching element in the direction of the movement axis (Z). Guides are provided and configured so the switching element in the switching chamber is guided along the movement axis (Z) in a linearly movable manner and held so a main axis (N) of the switching element, which runs perpendicularly with respect to the two main extension directions (X, Y) of the switching element, is oriented at least substantially parallel to the movement axis (Z).

Abstract: A switch unit, preferably implementing a circuit breaker, includes a contact slide unit formed by a contact slide, a fixed contact piece and a moveable contact piece), and a short-circuit release that acts to displace the moveable contact piece by means of a tappet in the event of a short-circuit. A moveable braking device is configured and arranged such that, following circuit opening displacement of the moveable contact piece in response to a short-circuit, the moveable brake device dampens the return, rebound movement of the moveable contact piece to reclose the circuit.

Abstract: Switchable grounded terminal loads are built into, or otherwise coupled to, connectors on motherboards and control devices. The terminal loads are coupled to the bus termination at the connector when the connector is “stuffed” (connected to a mating connector). The switchable grounded terminal loads replace dummy connectors in preventing empty “unstuffed” connectors from increasing error risks on active channels.

Abstract: Switchable grounded terminal loads are built into, or otherwise coupled to, connectors on motherboards and control devices. The terminal loads are coupled to the bus termination at the connector when the connector is “stuffed” (connected to a mating connector). The switchable grounded terminal loads replace dummy connectors in preventing empty “unstuffed” connectors from increasing error risks on active channels.

Abstract: A tactile button device is provided and is suitable to be sterilized. The tactile button device has at least one receptacle that is adapted to be filled at least partly with a material and further is configured so that the material filled into the receptacle is displaced when subjected to a pressure. At least one duct is connected to the receptacle and allows the pressure exerted to the material to be transmitted. A connector is connected to the at least one duct and is connectable to a detection device so that the pressure on the material is transmitted to the detection device.

Abstract: An arrangement of pushbutton switches with a programmable display that has a support structure with an assembly panel with openings for arranging there through an enclosure body of each push-button switch of the arrangement; a printed circuit board; and a shielding plate, wherein the enclosure body of each pushbutton comprises an appendix arranged through through-openings defined in the assembly panel, printed circuit board and plate; and a connector attached to the enclosure body that is opposite to and engaged with a connector of the printed circuit board, wherein each enclosure body is attached to the support structure by removable immobilizing means of said appendix with respect to said shielding plate, the immobilizing means comprising a nut with a coupling configuration to be coupled to a tubular shaft by a respective complementary coupling configuration integrated with or attached to the tubular shaft.

Abstract: Embodiments of the present invention provide a circuit structure that allows the use of a single sided Printed Circuit Board (PCB) with a mechanical key structure that has a light emitting element in the middle of the key structure. An LED with pins for protruding through a printed circuit board allows a layout only on the bottom side of the PCB. In one embodiment, the PCB includes at least one low ohm resister forming a bridge for a switch matrix conductor over a perpendicular switch matrix conductor.

Abstract: A crossbar structure of an electromagnetic contactor is provided, specifically, a crossbar structure of an electromagnetic contactor in which consistent performance is attained by preventing a moving mount from being flipped. The electromagnetic contactor includes a crossbar configured to move up and down and a moving contact point disposed on an installation groove, which is formed on the crossbar in a vertical direction, and brought in contact with or separated from a fixed contact point. The installation groove includes an insertion part into which the moving contact point is inserted and assembled and an operating part closely formed enough to prevent the moving contact point from being flipped when the moving contact point moves up and down.

Abstract: A contact slider unit is disclosed for a switching unit, in particular for a circuit breaker, having a contact slider and a contact piece. In an embodiment, the contact piece has a passage through which a tappet is guided.

Abstract: A press detection sensor contains a base member having predetermined length and width and also having a predetermined shape, a first conductor having predetermined length and being arranged on the base member, and a second conductor that is arranged on the base member with the second conductor being faced to the first conductor. The press detection sensor also contains a conductive contact body that is arranged between the first conductor and the second conductor. The conductive contact body connects the first and second conductors electrically in response to an external force. The press detection sensor further contains a covering member that includes the contact body on the inside thereof. The covering member covers a top of the base member which includes the first and second conductors. The covering member contains at least one of flexibility and elasticity.

Abstract: A touch pad module includes a circuit board and a trigger element. The circuit board includes a recessed area. The trigger element is disposed on the circuit board and covers the recessed area. When the trigger element deforms by an external force, at least a part of the trigger element is located in the recessed area.

Abstract: A moving contact-carrying carriage (8) for an electrical cut-off device which comprises several seats (80) arranged for receiving several parallel moving contacts (5A-5C) offset in space, and each of them is associated with a return mechanism (65). The carriage can be coupled with an actuator mechanism (6) of the device. The carriage (8) comprises an insulating support (81) which has parallel seats (80) and a supporting structure (9), surrounding the insulating support (81), for forming a load-absorbing belt therearound. In order to couple the carriage (8) with the actuator mechanism, the supporting structure (9) comprises a connecting part (91) positioned in a front section of the insulating support (81) and passing through the central seat (80) and resting against the central moving contact (5A), on a side opposite to the return mechanism (65), for directly transmitting driving efforts of the actuator mechanism when opening the electrical circuit.

Abstract: A switching subassembly includes a modular molded interconnect bracket and a switching device arranged on the modular molded interconnect bracket. The modular molded interconnect includes at least one electronic circuit trace arranged thereon configured to interconnect a portion of a flexible printed circuit board and to support a portion of the flexible printed circuit board. The switching device is configured to contact portions of the at least one electronic circuit trace.

Abstract: The invention relates to a switch contact subassembly (1) having a switch contact bridge (2) and a resilient element (3), for example, for an operating current of a switching element which switches an electric or hybrid motor vehicle. In order to be able to produce the switch contact subassembly (1) in a cost-effective and simple manner, there is provision according to the invention for the switch contact subassembly (1) to have a contact bridge retention member (4), the contact bridge retention member (4) having a securing base (14) for securing to an actuation member (15) for the switching element and at least one retention member (17) for positioning the switch contact bridge (2).

Abstract: A transmission cable including a transmission line, at least two electrically conductive line segments separated by a non-conductive gap, a bridging unit including at least one electrically conductive bridge segment capable of bridging the non-conductive gap, and a switching unit arranged to move the bridging unit and/or the transmission line to electrically connect the two line segments by closing the non-conductive gap using the bridge segment or to electrically disconnect the two line segments by opening the non-conductive gap.

Abstract: The invention relates to a single-pole switching unit (80) comprising electrical switching means comprising two stationary contacts (320) and a moving contact (330) including a bridge having two ends each able to cooperate with a stationary contact (320). The moving contact (330) includes a first branch (331) and a second branch (332) designed to connect the two stationary contacts (320), respectively and being movable relative to one another such that: the first branch (331) is separated from the stationary contacts (320), while the second branch (332) is still in contact with said stationary contacts when the contacts are opened; the second branch (332) is in contact with the stationary contacts (320), while the first branch (331) is separated from said contacts when the contacts are closed.

Abstract: A button mechanism includes a circuit structure and an actuating structure. The circuit structure includes a substrate, a first electrode layer, and a second electrode layer. The first electrode layer and the second electrode layer are disposed on the substrate, and the second electrode layer is separated from the first electrode layer. The first electrode layer includes a first section and a second section. The second electrode layer includes a third section and a fourth section. The second section stretches to the third section, and the fourth section stretches to the first section. A predetermined gap is formed between the first electrode layer and the second electrode layer, and the predetermined gap includes a plurality of curved portions. The actuating structure includes a conductive portion for conducting the first electrode layer and the second electrode layer.

Abstract: Embodiments of switches (10) include first and second electrical conductors (34, 36) suspended within an electrically-conductive housing (28), and a contact element (16) having an electrically-conductive portion (53b) that establishes electrical contact between the first and second electrical conductors (34, 36) when the contact element (16) is in a closed position. The electrically-conductive portion (53b) is electrically isolated from a ground plane (27) of the switch (10) by adjacent electrically-insulative portions (53a, 53c) of the contact element (16).

Abstract: An interrupter module for a molded case circuit breaker has a floating antifriction disc between the module casings and the blade carrier which overlays the blade carrier with rim walls of the disc. The rim walls are located at segments of the disc containing the drive pins of the module. If gases from circuit interruption expand the interrupter module sides and force the disc away from the blade carrier, the rim walls remain over the blade carrier and protect the drive pins from contaminants carried by the gases.

Abstract: A key structure with a scissors-type connecting member is provided. The scissors-type connecting member includes a first frame and a second frame. The first frame has a bulge. The second frame has a recess. The height of the bulge is smaller than the length of the recess entrance. The length of the recess bottom surface is greater than the length of the recess entrance. After the bulge of the first frame is introduced into the recess of the second frame, since the length of the recess bottom surface is greater than the length of the recess entrance, the possibility of detaching the bulge from the recess during the operation of the scissors-type connecting member will be minimized.

Abstract: A power adapter includes a shell, a power converter, a first power line, a second power line, a switch received in the shell, and a DC plug. The first power line connects the power rectifier to an external power source, and includes a first terminal and a second terminal. The second power line connects the power rectifier to the DC plug. The switch includes a fixed shaft fixed on the shell, a rotating plate rotatably positioned on the fixed shaft, a number of poles equidistantly disposed on the rotating plate, a number of conductive sheets for conducting the first and second terminal, and a stirring device connecting to the second power line. The conductive sheets are disposed on the rotating plate corresponding to the odd/even poles. When the second power line is pulled, the stirring device rotates the rotating plate to electrically connect or disconnect the first and second terminal.

Abstract: An electrical switch including at least one switching unit includes: a contact lever and two parallel plates, between which the contact lever is resiliently retained by way of pins. The contact lever is inserted into an electrically non-conductive housing of the switching unit, wherein at least one of the pins forms a retaining pin, wherein the length of the retaining pin exceeds the distance between the parallel plates and wherein the retaining pin extends through a hole in each of the two plates and is retained by one pin end in a retaining recess in the housing and by the other pin end in an opposite retaining recess in the housing.

Abstract: A switch structure on the sidewall of a circuit board for an electronic device and manufacturing methods of the circuit board are provided. The switch structure includes a circuit board, a plurality of conductive portions, and a movable unit. The conductive portions are formed on a sidewall of the circuit board and electrically insulated from each other. The movable unit is disposed corresponding to the conductive portions to electrically connect or disconnect the plurality of conductive portions to achieve the switch function. The switch structure utilizes the structural design of the circuit board to reduce the space on the circuit board preserved for a circuit board switch.

Abstract: A moving contact-carrying carriage (8) for an electrical cut-off device which comprises several seats (80) arranged for receiving several parallel moving contacts (5A-5C) offset in space, and each of them is associated with a return mechanism (65). The carriage can be coupled with an actuator mechanism (6) of the device. The carriage (8) comprises an insulating support (81) which has parallel seats (80) and a supporting structure (9), surrounding the insulating support (81), for forming a load-absorbing belt therearound. In order to couple the carriage (8) with the actuator mechanism, the supporting structure (9) comprises a connecting part (91) positioned in a front section of the insulating support (81) and passing through the central seat (80) and resting against the central moving contact (5A), on a side opposite to the return mechanism (65), for directly transmitting driving efforts of the actuator mechanism when opening the electrical circuit.

Abstract: A switch structure on the sidewall of a circuit board for an electronic device and manufacturing methods of the circuit board are provided. The switch structure includes a circuit board, a plurality of conductive portions, and a movable unit. The conductive portions are formed on a sidewall of the circuit board and electrically insulated from each other. The movable unit is disposed corresponding to the conductive portions to electrically connect or disconnect the plurality of conductive portions to achieve the switch function. The switch structure utilizes the structural design of the circuit board to reduce the space on the circuit board preserved for a circuit board switch.

Abstract: A keyboard includes a plug communicating with an external input device, a printed circuit board (PCB), and a base. The PCB includes a first power pad and a second power pad electrically connected to the plug via a cable. The PCB outputs a control signal to the plug via the cable in response to the first power pad and the second power pad being electrically connected. The base includes a control and at least one positioning element for positioning the control on the base. The control includes a pushbutton, a first pin electrically connected to the first power pad, and a second pin electrically connected to the second power pad. The first pin and the second pin are electrically connected in response to the pushbutton being pressed.

Abstract: An ultra-thin, electrically conductive slice for button use, which includes a non-metallic matrix and a metal mesh. The metal mesh is provided in the non-metallic matrix. A plurality of metal touch points are provided on the metal mesh and exposed out of a surface of the non-metallic matrix so as to enable the surface of the non-metallic matrix to form a dense, electrically conductive mesh. The non-metallic matrix is rubber or silica. The metal mesh is electrically conductive.

Abstract: An electrical switch assembly includes a first pair of busbars, each busbar having a first portion and a second portion, the first portion disposed at an angle with respect to the second portion, and a wedge-shaped assembly configured to be repositionable to form an electrical circuit between the first pair of busbars. Also described herein is a non-destructive testing system including the electrical switch assembly.

Abstract: A movable contact point board provided with contact points is urged in a direction of being away from stationary contact points by return springs each having the same size and the same characteristic, and is arranged as opposed to the stationary contact points. Return springs have the respective ends for supporting locations in the movable contact point board which are away from each other as having the contact points in the movable contact point board therebetween and support heights of the return springs at the stationary side differ with each other by D. When a plunger equipped with a holding portion having a flat surface as a bottom surface presses the movable contact point board, the contact point in the movable contact point board gets in contact with the stationary contact point at an inclined posture.

Abstract: A switch structure on the sidewall of a circuit board for an electronic device and manufacturing methods of the circuit board are provided. The switch structure includes a circuit board, a plurality of conductive portions, and a movable unit. The conductive portions are formed on a sidewall of the circuit board and electrically insulated from each other. The movable unit is disposed corresponding to the conductive portions to electrically connect or disconnect the plurality of conductive portions to achieve the switch function. The switch structure utilizes the structural design of the circuit board to reduce the space on the circuit board preserved for a circuit board switch.

Abstract: A contactor comprises, for each phase, a pair of contact devices which comprise a connection strip and at least two conductors provided with a stationary contact, and a movable contact bridge able to close the two stationary contacts or not. According to the invention, the contact device is formed from superposition of a number of pieces equal to the number of conductors, each piece comprising one of the conductors and a connection part corresponding to the connection strip but of smaller thickness. Each of the pieces can be made from folded metal. The connection parts are coupled to one another to form the connection strip by means of holes at the same time as the sets of bars are secured thereto.

Abstract: In one embodiment of the present invention, a production method for an electromagnetic switching device includes the following steps in the sequence listed: producing a one-piece switching chamber, producing a contact bridge carrier and equipping the contact bridge carrier with movable contact bridges, wherein the contact bridges include a plurality of primary contact bridges and at least one auxiliary contact bridge; inserting the contact bridge carrier equipped with the movable contact bridges into the switching chamber; inserting partition elements into the switching chamber so that each partition element is arranged between a bridge contact point of one of the primary contact bridges and a bridge contact point of one of the auxiliary contact bridges, and equipping the switching chamber with fixed primary counter-contact points; fixing primary covers to the switching chamber so that the primary covers cover the primary counter-contact points and fix the partition elements in the switching chamber.

Abstract: An installation switching device having at least one pole current path comprises two stationary contact pieces; a moving contact bridge including two moving contact pieces forming a double-break pole with the two stationary contact pieces; a contact pressure spring exerting a pressure on the moving contact bridge in a closing direction of the moving contact bridge; a pusher configured to act on the moving contact bridge counter to the pressure of the contact pressure spring in an opening direction, the pusher including a slide and a striking pin disposed moveably relative to the moving contact bridge and to one another in a movement direction of the moving contact bridge; a switch latch having a latching point; an operating lever configured to act on the pusher; and an electromagnetic release having an impact armature.

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.