Abstract: Proposed is an automatic transfer switch with an N-phase overlapping structure, the switch including: a driving unit including a drive shaft provided to generate power; a three-contact switching unit including a normal power shaft and an emergency power shaft provided to be rotated by the drive shaft, and a normal power terminal and an emergency power terminal for inputting/releasing normal power and emergency power; and an N-phase overlapping unit including a first insertion part having a first insertion hole, an N-phase normal contact terminal provided to input/release an N-phase normal power, a second insertion part having a second insertion hole, an N-phase emergency contact terminal provided to input/release an N-phase emergency power, and a connection bar connected between the first insertion part and the second insertion part so as to be interlocked with each other.

Abstract: A control module for an electric switch comprising: a body part, a main control shaft, an operating shaft and a drive system operationally connecting the main control shaft to the operating shaft such that the operating shaft is adapted to be rotated by the main control shaft. Rotation axes of the main control shaft and operating shaft are perpendicular to each other. The body part comprises a first side wall, a second side wall, a top wall and a bottom wall. The bottom wall is provided with a bottom recess adapted to receive a portion of an add-on, a bottom part of the main control shaft being accessible through the bottom recess.

Abstract: A plug-in connector cooperating with a terminal block includes a body having a cooperation assembly mechanically securing the plug-in connector on the terminal block, the body having a compartment accommodating a fuse element, a pair of plug contacts received within the compartment, and a handle part having an actuating portion and a linking portion. The plug contacts are each connected to a terminal of the fuse element. Each of the plug contacts has a contact tongue extending outside of the compartment, the contact tongue electrically secured to a bus bar of the terminal block. The linking portion is attached to the body and extends along a linking axis parallel to an insertion axis of a pin of the cooperation assembly. The actuating portion has an actuating surface extending transversely to the insertion axis and cooperating with a marking element disposed along the actuating surface.

Abstract: Implementations of the subject matter described herein provide a switching apparatus. The switching apparatus includes: a switching component including a first main shaft, which is adapted to selectively connect and disconnect at least one circuit in response to the rotation of the first main shaft; and an operating mechanism including a second main shaft for actuating the first main shaft to rotate via the second main shaft; wherein the switching component further includes a first interface, and the operating mechanism further includes a second interface, and the second main shaft to be detachably coupled to the first main shaft in response to the engagement of the first interface and the second interface.

Abstract: An arc quenching device creates a fault on a bus. A lockout mechanism of a circuit breaker feeding the bus is responsively actuated. Actuating the lockout mechanism may include releasing a spring-loaded mechanism mounted on a cassette that holds the circuit breaker to cause the mechanism to engage a lockout member of the circuit breaker.

Abstract: An assembly or adapter configured to provide a supply-side interconnect of electrical power to a distribution board. The adapter may be incorporated internal or external to the distribution board, by occupying the space of one or more circuit breakers, inserting an adapter into a meter termination socket, or the like. The adapter includes terminals provided to route the conductors from the utility to a breakout panel (or subpanel) for adding power devices as a supply side interconnect, and back to a regular route that may go through the meter and/or the main circuit breaker, and on to the loads. A switching component may provide an inline configuration that configures the conductors for backup function, and a parallel configuration that is a parallel interconnecting route when utility service is available.

Abstract: An automatic power transfer switching mechanism includes several links and a push member. The links move to rotate the push member. The push member has two push portions configured to push two power switches. The push member is rotatable about a first axis located between the two push portions so that when one of the push portion moves forwards, the other push portion moves backwards. Therefore, when one push portion moves forward to push one power switch on, the other push portion moves backwards to simultaneously push the other power switch off. The power transfer can be switched automatically without delay.

Abstract: An interlocking structure of a power conversion system is provided. A first power circuit group is connected to a first power source and includes a first and a fourth switch. A second power circuit group is connected to a second power source and includes a second and a fifth switch. A limiting mechanism includes a first limiting portion, a second limiting portion, a fourth limiting portion, a fifth limiting portion, a first accommodating portion, and a second accommodating portion. The first switch is switched off to disconnect the first power source. Then, a limiting structure is moved to connect the second power source. Accordingly, the first power source is disconnected, and the second power source is connected, allowing repair or maintenance of the first power source to be performed without interrupting the supply of power from the power conversion system.

Abstract: Provided is a multi-pole molded case circuit breaker (MCCB) with an insulation barrier for a rotary pin, in which an insulation barrier is provided in a rotary pin for inter-phase power transmission to prevent dielectric breakdown. The multi-pole MCCB includes a shaft assembly having a movable contactor and having a plurality of rotary pin holes formed in a penetrating manner, a base assembly to which the shaft assembly is rotatably accommodated to be coupled, a switching mechanism coupled to an upper portion of the base assembly and rotating the shaft assembly, a plurality of rotary pins coupled to the plurality of rotary pin holes in a penetrating manner, and an insulation barrier formed of an insulating material and covering the plurality of rotary pins.

Abstract: An automatic autonomous redundant switch configured for providing energy from either a first power source or a second power source to a load is provided. The automatic switch includes a first automatic transfer switch (ATS) and a second ATS. The automatic switch further includes an interconnecting bus configured to connect the first ATS and the second ATS, and at least one controller configured to control the operation of the first ATS and the second ATS. Still further, the first ATS and the second ATS each include a respective transfer-switch mechanism, a respective bus attachment configured to connect to the interconnecting bus, and a respective motorized rack-out mechanism having a powered actuator.

Abstract: A fastener is provided for ganging or joining two or more switch handles to one another. The fastener includes a head at one end and an elongated shank extending from the head. The shank includes a threaded portion adjacent the head that threadingly engages one of the switch handles. The shank extends longitudinally from the threaded portion through the threadingly engaged switch handle and through one or more additional switch handles to gang the switch handles to one another.

Abstract: A first breaker is adapted to be connected to an external source of electrical power, and a second breaker is adapted to be connected to an electrical generator. The first breaker is in an on position when the second breaker is in an off position, and the first breaker is in an off position when the second breaker is in an on position. The breakers are in combination with a toggle adapted to simultaneously operate the first breaker and the second breaker. The first breaker has a first breaker hole, and the second breaker has a second breaker hole, where the first breaker electrically connects an external power transmission to a breaker box, and the second breaker electrically connects a generator to the breaker box.

Abstract: The electromagnetic contactor includes a first frame in which an operation electromagnet is mounted; a second frame in which a contact mechanism is mounted; and a snap-fit section that is made up of a fitting protruding section and a hook section formed to one and the other of the first and second frame, respectively, the hook section fitting to the fitting protruding section. The hook section has a flexible projecting plate section formed in a projecting manner to an open end of either the first or second frame and a fitting section formed at a tip of the flexible projecting plate section, the fitting section fitting to the fitting protruding section. The flexible projecting plate section is provided with elasticity that fits the fitting section to a base side of the fitting protruding section in accordance with progress of wear between the fitting section and the fitting protruding section.

Abstract: A switching device includes multiple switches configured to selectively connect one of two power sources to electrical loads. The switching device may include either single-pole or double-pole, double-throw switches and corresponding single or double circuit breakers. The single and double circuit breakers are each configured to be inserted into openings having the same physical dimensions. At least one of the switches is a double-pole, double-throw switch, allowing two branch circuits to be transferred between power sources via the switch. A double breaker corresponding to the double-pole, double-throw transfer switch permits each of the branch circuits being switched by the double-throw switch to be wired through a separate protective circuit.

Abstract: A solid state lighting switch can include a first input control that can be configured to adjust a dimming indication or color indication for a solid state lighting fixture that is configured for coupling to the solid state lighting switch. A selective linking mechanism can be configured to activate a linked mode of operation of the switch to link the dimming indication to the color indication or to activate an unlinked mode of operation of the switch to unlink the dimming indication from the color indication.

Abstract: The present invention relates to an auxiliary contact mechanism of an electromagnetic contactor, and more particularly, to an auxiliary contact mechanism of an electromagnetic contactor capable of maximizing a time duration for which power is supplied to a magnetic coil for switching a main contact until the main contact is closed. The auxiliary contact mechanism of an electromagnetic contactor, includes: a case formed to have a box shape; an auxiliary sliding member installed above the case, and moving up and down by receiving a pressure from a main contact sliding member; an elastic member accommodated in an insertion groove formed in the auxiliary sliding member; a pressing member insertion-installed below the auxiliary sliding member, and moving up and down by an elastic force of the elastic member; and a micro switch turned on/off by the pressing member.

Abstract: An automatic transfer switch (ATS) for supplying power to a load is provided. The ATS includes a main transfer switch portion configured to connect one of a first or second power source to the load. The ATS also includes a bypass transfer switch portion configured to form a bypass connection from either the first or second power source to the load. The bypass transfer switch portion includes (i) a first bypass switch configured to connect the first power source to the load upon closing of the first bypass switch and (ii) a second bypass switch configured to connect the second power source to the load upon closing of the second bypass switch. Further, the ATS includes a primary load connection connecting the main transfer switch portion to the load, where the primary load connection is formed at least in part by the first and second bypass switches.

Abstract: A switch coupling assembly is configured for coupling switch handles to provide simultaneous actuation and deactivation of an electrical device. The switch handles are arranged in a side by side configuration and have passages are aligned. A coupling rod is inserted through the passages in the handles. A spacer is positioned between the switch handles and receives the coupling rod therethrough. An outside surface of the coupling rod is threaded to interact with either or both of the inner surface of the spacer or the inner surface of the handles in order to prevent inadvertent axial motion of the rod relative to the spacer or the switch handles.

Abstract: A connector includes a connecting terminal, a fixed contact, a movable plate, a movable contact provided at an end of the movable plate, a card that includes an insulator and contacts the movable plate, a button that contacts the card, an opening spring connected to the button, and a sliding operation part that controls a contact between the fixed contact and the movable contact. When the sliding operation part is moved in a first direction, the movable contact is brought into contact with the fixed contact and the connector is turned on. When the sliding operation part is moved in a second direction opposite to the first direction, the movable contact is caused to move away from the fixed contact and the connector is turned off. The sliding operation part is provided on a surface that is different from a surface on which the connecting terminal is provided.

Abstract: Apparatus are described herein that provide a circuit breaker handle tie configured to mechanically couple circuit breaker handles of different configurations to one another.

Abstract: Various systems and method for distributing electrical power are provided. In one embodiment, a system includes a first inverter coupled to an electrical bus, a second inverter coupled to the electrical bus, a filter including a first inductor and a second inductor, and a transfer switch circuit coupled between the first inverter and the second inverter and a load. The transfer switch circuit is configured to transfer power from the first inverter through the first inductor to the load and transfer power from the second inverter through the second inductor to the load in a first mode of operation. The transfer switch circuit is further configured to transfer power from the first inverter through the first inductor and through the second inductor to the load in a second mode of operation.

Abstract: A molded case circuit breaker is provided. The molded case circuit breaker includes a molded base defining at least one cavity and a tie bar coupled to the molded base and extending across the cavity. The tie bar is configured to reduce fracture and separation of the molded base during a high pressure event.

Abstract: Apparatus are described herein that provide a circuit breaker handle tie configured to mechanically couple circuit breaker handles of different configurations to one another.

Abstract: A multipolar electrical switch includes at least one central pole housing, which adjoins two adjacent pole housings of the switch. In at least one embodiment of the invention, an electrical switching mechanism for switching an electrical phase current on and off is contained in each of the pole housings respectively. The central pole housing is equipped with a fastening element, which extends through the central pole housing into the two adjacent pole housings, namely in each instance to at most the center of the adjacent pole housings.

Abstract: An electrical distribution panel includes a panel box locating a ground bus in electrical connection with a ground input lug, a neutral bus in electrical connection with a neutral input lug, and a primary power bus connected to a power input lug through a main breaker switch. The main breaker switch is operable between an on position in which the primary power bus receives power and an off position in which the primary power bus is disconnected. Primary circuit breakers can be supported in the usual manner in connection with the primary power bus. One or more auxiliary circuit breakers are connected to the power input lug to receive power independently of the main breaker switch. An electrical outlet can thus be integrally supported in one of the side walls of the panel box to receive power independently of the main breaker switch.

Abstract: An interlocking mechanism for interlocking a first and a second low voltage switching devices, wherein each of the switching devices includes a movable contact part, a stationary contact part and, an actuating unit for operating the movable contact part in a direction and making connection or disconnection with the stationary contact part. The interlocking mechanism includes a first and a second housing connected to each other, a first and a second sliding bar. The first sliding bar is arranged on the first housing and connects to the actuating unit of the first switching device. The second sliding bar is arranged on the second housing and connects to the actuating unit of the second switching device. A sliding plane is defined and has a X- and Y-axis, the Y-axis being defined in the direction of motion of the actuating unit of the switching devices.

Abstract: A handle tie is provided that includes a connecting member, a first retaining member, and a second retaining member. The first retaining member is fixed to the connecting member and is configured to retain a first circuit breaker handle having a first configuration. The second retaining member is fixed to the connecting member and is configured to retain a second circuit breaker handle having a second configuration that is different from the first configuration.

Abstract: An electrical panelboard enclosure includes an enclosure housing with an interior equipment chamber accessible by way of a service entrance door. A service panel is configured to receive power from a main power source. A main power breaker has a main power breaker toggle switch and is positionable between a power-on state and a power-off state to selectively activate and deactivate the main power. A power cutoff switch mechanism is operable from outside the service entrance door and is positionable between a power-on state and a power-off state to mechanically engage and deactivate the main power breaker toggle switch and cutoff the main power without opening the service entrance door. A lockout system is operable to prevent the service entrance door from being secured in a closed position unless the main power breaker and the power cutoff switch mechanism are in the same state.

Abstract: The disclosed concept relates to a handle tie apparatus for connecting two or more operating handles of two or more electrical switching assemblies for simultaneous operation of the operating handles, such as switching from “on” position to “off” position. The handle tie apparatus including apertures formed therein for receiving the operating handles and slots having barbs configured therein for mechanically engaging and securing the operating handles in said handle tie apparatus.

Abstract: An interlocking mechanism for interlocking a first and a second low voltage switching devices, wherein each of the switching devices includes a movable contact part, a stationary contact part and, an actuating unit for operating the movable contact part in a direction and making connection or disconnection with the stationary contact part. The interlocking mechanism includes a first and a second housing connected to each other, a first and a second sliding bar. The first sliding bar is arranged on the first housing and connects to the actuating unit of the first switching device. The second sliding bar is arranged on the second housing and connects to the actuating unit of the second switching device. A sliding plane is defined and has a X- and Y-axis, the Y-axis being defined in the direction of motion of the actuating unit of the switching devices.

Abstract: A transfer switch mountable in a standard electrical panel connects either a utility supply or an auxiliary supply to an electrical system. An internal mechanical interlock prevents both the utility supply and the auxiliary supply from simultaneously being connected to the system. The transfer switch may utilize either a rocker-style or a blade style switch. A light-emitting diode provides an indication of whether the utility supply is connected to and a voltage is present at the utility supply terminal. A power meter provides an indication of the magnitude of power drawn from the auxiliary supply when the auxiliary supply is connected to the load.

Abstract: A single module circuit breaker housing includes a first circuit breaker, wherein the first circuit breaker includes a first shaft assembly and a first contact mechanism coupled to the first shaft assembly, a second circuit breaker, wherein the second circuit breaker includes a second shaft assembly and a second contact mechanism coupled to the second shaft assembly, a first linkage coupled to the first shaft assembly and the second contact mechanism, and a second linkage coupled to the second shaft assembly and the first contact mechanism.

Abstract: An electrical switching apparatus includes an enclosure having an opening, a single operating handle disposed through the enclosure opening, a first pole disposed in the enclosure and including first separable contacts, a first operating mechanism to open and close the first contacts, and a first operating member cooperating with the first operating mechanism to open and close the first contacts. A second pole is disposed in the enclosure and includes second separable contacts, a second operating mechanism to open and close the second contacts, and a second operating member cooperating with the second operating mechanism to open and close the second contacts. The single operating handle, centered between parallel poles, includes a first projection within the enclosure cooperating with the first operating member to open and close the first contacts, and a second projection within the enclosure cooperating with the second operating member to open and close the second contacts.

Abstract: The present invention discloses a multi-pole circuit breaker with auxiliary supports, which comprises a base, a plurality of single-pole circuit breaking units, an operating mechanism and a rotation axis assembly, wherein the rotation axis assembly consists of a plurality of supporting assemblies and a plurality of support shaft parts in series; each of the support shaft parts is provided with a movable contact bridge; each of the supporting assembly consists of a rotation axis, an auxiliary support, an auxiliary support bearing and at least one supporting rod; the rotation axis maintains synchronous revolution with the support shaft parts; the outside of the bearing is tightly assembled with a bearing hole of the auxiliary support, while the inside is tightly assembled with the rotation axis; the supporting rod is tightly assembled with a supporting rod installing hole on the auxiliary support; the operating mechanism is fixedly connected with the supporting rod; and the supporting rod is fixedly installed o

Abstract: A saw assembly includes a housing, a drive member, a motor, a switch, a trigger, a lockout lever, a stop structure, and a lock-on member. The housing defines an interior space, and has a forward housing portion defining a forward housing opening and a rearward housing portion defining a rearward housing opening. The drive member extends through the forward housing opening, and is configured to be moved in a repeating pattern. The motor is positioned in the interior space and is configured to move the drive member in the repeating pattern. The switch is positioned in the interior space and has an actuator movable between an actuated and a deactuated position. When the switch is in the actuated position, the motor moves the drive member in the repeating pattern, and when the switch is in the deactuated position, the motor does not move the drive member in the repeating pattern.

Abstract: Apparatus are described herein that provide a circuit breaker handle tie configured to mechanically couple circuit breaker handles of different configurations to one another.

Abstract: A MOC operator structure for a circuit breaker includes linkage structure coupled between the operating mechanism and an interface structure. An armature is associated with the linkage structure. Permanent magnet structure is associated with the circuit breaker and is disposed generally adjacent to the armature. Wherein, when the operating mechanism is coupled with the linkage structure and the operating mechanism moves in a first direction, a portion of the linkage structure moves in a first direction and moves the MOC operator structure to an open position, with the armature being magnetically engaged with permanent magnet structure to maintain the MOC operator structure in the open position. When the portion of the operating mechanism moves in a second direction, the portion of the linkage structure moves in a second direction and moves the MOC operator structure to a closed position, with the armature magnetically disengaging from the permanent magnet structure.

Abstract: An electrical distribution panel includes a panel box locating a ground bus in electrical connection with a ground input lug, a neutral bus in electrical connection with a neutral input lug, and a primary power bus connected to a power input lug through a main breaker switch. The main breaker switch is operable between an on position in which the primary power bus receives power and an off position in which the primary power bus is disconnected. Primary circuit breakers can be supported in the usual manner in connection with the primary power bus. One or more auxiliary circuit breakers are connected to the power input lug to receive power independently of the main breaker switch. An electrical outlet can thus be integrally supported in one of the side walls of the panel box to receive power independently of the main breaker switch.

Abstract: Provided herein is a mechanism for correcting the deformation generated at a portion of the rotation pin between a single pole unit farthest away from a switching mechanism and a single pole unit adjacent thereto, and there is disclosed a correction plate provided at a portion of the pair of rotation pins located between a single pole unit farthest away from the switching mechanism and a single pole unit adjacent thereto, having a pair of rotation pin through hole portions to allow the pair of rotation pins to be penetrated, respectively, and a pair of adjustment extending portions extended in the direction in which the rotation pins penetrate at the upper or lower portion of the rotation pin through hole portions to determine the height of penetration allowance hole of the rotation pins together with the rotation pin through hole portions.

Abstract: In an undervoltage tripping unit of at least one embodiment, an armature acts on a tripping slide via a drum. During tripping, an auxiliary switch is closed. In order to reset the under-voltage tripping unit after tripping, a latching mechanism of an associated circuit breaker acts on the drum via a driver bolt. At the same time, a projecting element is formed on the drum and closes the auxiliary switch when the drum is rotated back. The auxiliary switch therefore need not itself be directly coupled to the latching mechanism.

Abstract: An electrical panelboard enclosure includes a primary service panel configured to receive power from a main power source and an alternate power source, an alternate power source connector array, and a distribution panel that delivers main or alternate power to subsidiary load circuits. A service transfer switch unit includes a main power breaker and an alternate power breaker having mutually interlocked toggle switches for respectively activating/deactivating the main and alternate power. The panelboard enclosure further includes a power cutoff switch operable from outside a service entrance door of the enclosure to mechanically engage and deactivate the main power breaker toggle switch.

Abstract: This electric switching system comprises first, second and third input terminals, a first, a second and a third output terminal, an electric switching module and a control module for controlling the switching module. The electric switching module comprises two first switches and two second switches, each switch comprising a fixed input contact, a fixed output contact and a mobile contact, the two fixed contacts being connected via the mobile contact in closed position of the switch and insulated from each other in open position of the switch, and a holder member holding the mobile contacts and being able to be moved by an electric driving device between a first position and a second position, the holder member comprising a first mechanical coupling element with the driving device in a primary configuration of the driving device relative to the switching module.

Abstract: An electrical switching device and method are disclosed. The electrical switching device can include two movable contacts. During opening of the switching device, the two movable contacts move in a first direction until one of the movable contacts engages a blocking member. The other movable contact continues in the first direction, effecting opening of the switching device. In a particular implementation, the movable contact that engages the blocking member “bounces” in a second direction after contacting the blocking member. This causes the contacts of the switching device to be separated very quickly, reducing electrical arcing during opening of the switching device.

Abstract: Provided herein is a power transmission mechanism of a four poles circuit breaker in which the contact points of a neutral pole thereof are brought into contact earlier at the time of closing and separated later at the time of opening than those of the other poles thereof, and according to the present invention, there is disclosed a power transmission mechanism of a four poles circuit breaker comprising: a switching shaft configured to provide a driving force for switching to the movable contactors of the poles; an arm provided to correspond to the four poles to transfer the rotational torque of the switching shaft; and a link configured to transfer the rotational torque of the arm to the movable contactor as a switching force, and provided to correspond to the four poles, wherein the sum of the length of the arm and the link in a neutral pole is longer than the sum of the length of the arm and the link in the poles excluding the neutral pole.

Abstract: Disclosed is a transfer device for an automatic transfer switch. With the configuration of the transfer device, the transfer device, which is installed between a plurality of air circuit breakers to allow switching of a closed state and a tripped state of the plurality of air circuit breakers, can be modularized so as to be easily assembled. A length of a transmission rod can be adjusted so as to facilitate assembly and maintenance of the transfer device and also minimize the probability of occurring an assembly error, allowing accurate closing and trip operations. The transmission rod may be provided with a buffer to reduce impact noise generated upon switching of the closing and trip operations of each air circuit breaker and enhance reliability of the device.

Abstract: A multi-pole handle lock having a base plate and movable locking plate assembly that is adapted to mount on to at least two circuit breakers. A handle restrictor plate is mounted on the base plate for translational movement while maintaining the circuit breaker handles in the same position as each other. The handle restrictor plate allows each handle to independently move to the tripped position, while allowing the restricted circuit breakers to operate as a logical group. The low profile of the plates, allows visual inspection of the handle ends to determine their tie status.

Abstract: A changeover operation device, for changing over the positions of at least two components to establish three or more speed modes in a speed changer mechanism accommodated within a housing having an opening, includes operation handles arranged in a corresponding relationship with the components. Each of the operation handles is movable between two specified positions along a specified operation direction to change over the positions of the components. The operation handles are continuously arranged within the opening of the housing, one of the operation handles being partially overlapped with the other.

Abstract: An apparatus is disclosed for mutual interlocking of two switches, in particular circuit breakers. In at least one embodiment, the apparatus includes two plungers which each engage in one of the two switches and can be moved in the plunger longitudinal direction, wherein, when one switch is being switched on, the plunger which engages in this switch is moved by pivoting of a control disk from its nil-point position to its opening position. In at least one embodiment, the apparatus includes a blocking device which blocks pivoting of the other control disk by moving the plunger to its opening position. In order to achieve a maintenance-free apparatus, in at least one embodiment it is proposed that at least one blocking element of the blocking device is moved by the plunger when this plunger is being moved to its opening position, such that pivoting of the other control disk with respect to the other plunger, which is located in the nil-point position, is blocked.

Abstract: A single module circuit breaker housing includes a first circuit breaker, wherein the first circuit breaker includes a first shaft assembly and a first contact mechanism coupled to the first shaft assembly, a second circuit breaker, wherein the second circuit breaker includes a second shaft assembly and a second contact mechanism coupled to the second shaft assembly, a first linkage coupled to the first shaft assembly and the second contact mechanism, and a second linkage coupled to the second shaft assembly and the first contact mechanism.

Abstract: An apparatus is disclosed for mutually locking two switches, in particular circuit breakers, with two plungers which move in opposition to one another via a forced mechanical coupling. When one switch opens, one plunger is shifted into its opening position and the other plunger is shifted into its locking position. In order to achieve a maintenance-free apparatus, at least one embodiment of the invention proposes that each plunger has a toothed rack, which meshes with a gearwheel, on which in each case one radial lever is arranged. The levers are connected in articulated fashion to one another via a connecting rod and a stop lever is mounted in rotary fashion on each gearwheel and, when the plungers are located in the zero position, bears in each case against a fixing stop.