299results about "Circuit-breaking switch contacts" patented technology

The invention discloses a dynamic closed-loop management method for bridge-shaped contact performance, and relates to the technical field of power system protection. The method comprises the following steps: S1, a dynamic sensing process: acquiring multi-source dynamic parameters of a bridge-shaped contact in a non-intrusive mode; s2, a quantitative evaluation process: fusing the multi-source dynamic parameters and the static parameters, and calculating a health index or a health level of the contact through a preset model; s3, adaptively optimizing the process, dynamically adjusting the closing energy or protection parameters of the circuit breaker according to the health state, and compensating the performance change of the contact; and S4, a predictive maintenance process: performing trend extrapolation based on the historical data of the health index, predicting the residual life and generating a maintenance suggestion. The processes are sequentially connected and cyclically iterated to form dynamic closed-loop management, so that the problems of one-sided parameter sensing, inaccurate evaluation, fixed parameters and maintenance lag in the prior art are solved, the operation reliability of the bridge-shaped contact is improved, the service life of equipment is prolonged, and the operation and maintenance cost is reduced.

The utility model relates to the technical field of circuit breaker structures, in particular to a rotating shaft structure of a double-breakpoint molded case circuit breaker, which is characterized in that a rotating shaft main body is of an integral structure design, a contact groove is formed in the rotating shaft main body along the radial direction, the middle part of a moving contact is inserted into the contact groove, and two ends of the moving contact penetrate out along an opening of the contact groove; the static spring shaft and the moving spring shaft are used for being in butt joint with the static contact, the static spring shaft and the moving spring shaft are located on the two sides of the moving contact respectively, the two ends of the contact spring are connected to the static spring shaft and the moving spring shaft respectively, and the moving spring shaft is pulled through elastic tension of the contact spring so that the two sides of the moving contact can abut against the inner side wall of the contact groove respectively. Due to the integral structure design of the rotating shaft main body, the three-phase synchronism of the molded case circuit breaker is consistent, the limit breaking capacity and the operation breaking capacity of the circuit breaker are greatly improved, the safety and the reliability of the circuit breaker in operation are improved, and the electrical life of the circuit breaker is prolonged.

A circuit breaker relates to the technical field of low-voltage electrical appliances and comprises a shell, a handle, an operating mechanism and a contact mechanism, the shell is provided with a first rotating shaft and a second rotating shaft, the operating mechanism is mounted on the first rotating shaft and comprises a mechanism seat, a jump fastener and a lock fastener, the contact mechanism comprises a moving contact and a static contact, the moving contact is mounted on the second rotating shaft, and the static contact is mounted on the second rotating shaft. The handle and the jump fastener are connected through a first connecting rod. The jump fastener and the moving contact are connected through a second connecting rod. During normal switching-on or switching-off operation, the locking fastener is buckled with the tripping fastener, and the handle is driven to drive the mechanism seat to rotate around the first rotating shaft through the first connecting rod, so that the moving contact is driven to be close to or far away from the static contact through the tripping fastener and the second connecting rod; when a fault is tripped, the locking piece and the tripping piece are tripped, and the moving contact is driven to rotate around the second rotating shaft so as to be far away from the static contact. According to the circuit breaker, the operating mechanism and the moving contact are respectively arranged on different rotating shafts, and the motion decoupling of the operating mechanism and the moving contact is realized during fault tripping, so that the moving contact can be quickly broken.

The invention discloses a magnetic rotation arc extinguishing circuit breaker contact structure, and belongs to the technical field of high-voltage electric connectors. Comprising an arc extinguishing device, a connecting device and a circuit breaker contact, the arc extinguishing device can be connected with the circuit breaker contact through the connecting device, the arc extinguishing device is integrally of a cylindrical structure, a longitudinal magnetic field is generated when current flows through the arc extinguishing device, and when an arc passes through the middle area of the arc extinguishing device, the arc is effectively stretched and rapidly extinguished under the action of the magnetic field. The connecting device comprises a centering piece and a fixing assembly, the centering piece can fix the arc extinguishing device on the axis of the centering piece, and the fixing assembly can fix the arc extinguishing device. Through the arc extinguishing assembly, a longitudinal magnetic field is formed when current passes through the arc extinguishing assembly, and the arc rotates and stretches along a spiral path under the action of magnetic field force, so that the arc extinguishing efficiency of the circuit breaker is remarkably improved, and the problem that the magnetic field direction is inconsistent with the arc flowing direction in the prior art is solved.

The utility model discloses a residual current operated circuit breaker, which comprises a circuit breaker shell and a rotating shaft, and the rotating shaft is rotatably connected with the circuit breaker shell. At least one mounting groove is formed in the rotating shaft, a moving contact and a contact torsion spring are arranged in each mounting groove, and one end of each contact torsion spring abuts against the corresponding moving contact; wherein the mounting groove is provided with an abutting wall and two side walls, and the two side walls are arranged on the two sides of the abutting wall respectively; abutting structures are arranged on the two side walls, and each abutting structure is provided with a first gear and a second gear; the other end of the contact torsion spring abuts against one of the abutting wall, the first gear and the second gear. The deformation quantity of the contact torsion spring when the contact torsion spring abuts against the abutting wall is smaller than the deformation quantity of the contact torsion spring when the contact torsion spring abuts against the first gear, and the deformation quantity of the contact torsion spring when the contact torsion spring abuts against the first gear is smaller than the deformation quantity of the contact torsion spring when the contact torsion spring abuts against the second gear. The pressure adjusting device has the advantage of being adjustable in pressure.

The utility model provides a moving contact system and a circuit breaker comprising the same. The moving contact system comprises a plurality of contact fingers which are arranged in parallel; the contact supporting piece comprises a supporting plate and a pair of supporting arms arranged on the two sides of the supporting plate, and the first ends of the plurality of contact fingers are pivotally installed between the pair of supporting arms; the plurality of springs are arranged corresponding to the plurality of contact fingers and are positioned between the plurality of contact fingers and the supporting plate of the contact supporting piece; and the insulating grating comprises a connecting part which is arranged between the contact finger and the spring. According to the moving contact system, the insulating grating is arranged between the contact finger and the corresponding spring, so that the spring can provide larger contact pressure for overcoming electro-dynamic repulsive force during short-time tolerance, the tolerance performance is improved, meanwhile, the insulating grating and the contact finger can keep synchronous movement, friction force is reduced in the switching-on / switching-off process, and the service life of the moving contact system is prolonged. And the mechanical performance of the circuit breaker is improved.

The application relates to the technical field of switch equipment, in particular to an arc-extinguishing chamber with a flow guide structure and a circuit breaker. The arc-extinguishing chamber with the flow guide structure comprises a contact seat, a static support and a flow guide cylinder, the contact seat is provided with an axial flow hole, the static support is a tubular structure with an open end, is sleeved on the contact seat through the open end, the flow guide cylinder is arranged in the static support along an axial direction, the flow guide cylinder and the static support surround an annular flow guide channel, a through hole is formed in the outer wall of the static support, a gas baffle is fixedly installed on the outer wall of the static support and corresponds to the through hole, and the gas baffle is provided with a gas discharge hole. The arc-extinguishing chamber with the flow guide structure can prolong the discharge path of the hot airflow and reduce the flow speed, can effectively prevent a large amount of foreign matters such as metal particles and dust carried in the hot airflow from being discharged, avoids threatening the ground or interphase insulation at the tail of the airflow channel, and improves the insulation reliability.

This application provides an arc-blocking device and a circuit breaker, belonging to the field of electrical equipment technology. In this arc-blocking device, one end of an elastic element is connected to the circuit breaker housing, and the other end is connected to an arc-blocking element, which is located on the movement trajectory of the circuit breaker's moving contact. When the moving and stationary contacts of the circuit breaker are in contact, the arc-blocking element is located on the side of the moving contact facing away from the stationary contact. During the separation process of the moving and stationary contacts, the moving contact pushes against the first side of the arc-blocking element, causing the arc-blocking element to drive the elastic element to bend and deform in the first direction until the moving contact slips off from the first side. Then, under the elastic force of the elastic element, the arc-blocking element moves in the second direction to between the moving and stationary contacts, thereby forcibly cutting off the arc generated when the moving and stationary contacts separate. It has good breaking capacity and can effectively improve the arc-extinguishing capability of the circuit breaker. Furthermore, the arc-blocking device provided in this embodiment has a simple structure, is easy to assemble, operates reliably, and has a certain degree of universality.

An operating mechanism for a circuit breaker includes: a first base plate, a second base plate, a first linkage mechanism, and a second linkage mechanism. The first and second linkage mechanisms each include a first link, a second link, and a third link. One end of the first and third links is pivotally connected to the corresponding base plate at a first hinge point and a third hinge point, respectively. One end of the second link is hinged to the free end of the third link, and the other end is hinged to the middle of the first link at a second hinge point. The first link includes a first hole provided on its free end. An output shaft extends through the first hole of the first link of the first and second linkage mechanisms. The first and / or second linkage mechanism further includes a fourth link. One end of the fourth link is pivotally connected to the first hinge point, and the fourth link is hinged at the middle of the second hinge point. The fourth link has a second hole on its free end, and the output shaft extends through the second hole.

The invention provides a circuit breaker and an uninterruptible power supply. The circuit breaker comprises a first busbar, a second busbar, a main contact and a plurality of arc contacts, the arc contact comprises an arc moving contact and an arc static contact. When the arc moving contact is in contact with the arc static contact, the plurality of arc contacts are connected in series through the conductive piece, the arc contact located at the head end of the plurality of arc contacts connected in series is connected with the first busbar, and the arc contact located at the tail end of the plurality of arc contacts connected in series is connected with the second busbar. When the arc moving contact is in contact with the arc static contact, the multiple arc contacts are connected in series through the conductive pieces, so that the arc contacts can generate multiple sections of series-connected arcs at the breaking moment, the sum of the voltages of the multiple sections of arcs is far higher than the system power supply voltage after the voltages of the multiple sections of arcs are superposed, the arcing duration can be shortened through the high voltage difference, and the fault can be rapidly cut off. Meanwhile, arc energy is dispersed to a plurality of fractures, heat concentration is avoided, and permanent damage to the arc contact and the internal structure of the circuit breaker caused by high-temperature arc ablation can be prevented.

The utility model belongs to the technical field of circuit breakers, and particularly discloses an operating mechanism of a molded case circuit breaker, which comprises a moving contact, a rotating shaft, a lower connecting rod, a connecting rod shaft, an upper connecting rod, a main spring and a closing lever, and is characterized in that the rotating shaft is rotatably mounted on a mechanism side plate, one end of the lower connecting rod is connected with the rotating shaft, and the other end of the lower connecting rod is mounted on the connecting rod shaft; one end of the upper connecting rod is connected with the connecting rod shaft, and the other end of the upper connecting rod is installed on the jump pin assembly. One end of the main spring is connected with the connecting rod shaft, the other end of the main spring is fixedly connected with the closing lever, and the closing lever is installed on the mechanism side plate. According to the utility model, a novel operating mechanism is designed, the operating mechanism is applied to the molded case circuit breaker, the AC / DC universal requirement is met, the modularized horizontal mechanism with a miniaturized characteristic is provided, and the adaptive circuit breaker can have more space for insulation design; the whole structure is installed on the mechanism side plate, the space utilization rate is improved, and the rotating shaft is installed on the mechanism side plate, so that positioning of the rotating shaft is facilitated.

The utility model discloses a kind of moulded case circuit breaker conducting systems, including base, multiple contact cavities are formed by multiple arrangement settings baffle in the base, multiple rotating cavities are opened in the base middle part in contact cavity opposite position, movable contact assembly is rotatably connected in the rotating cavity, static contact assembly that is installed in contact cavity is cooperated with movable contact assembly and realizes on-off, connection position is opened in the base surface front end, the static contact assembly includes static contact, first arc-extinguishing chamber and fixed baffle, one end of the static contact is set in contact cavity, the other end of the static contact extends to connection position, first arc-extinguishing chamber is installed below static contact, fixed baffle is arranged in first arc-extinguishing chamber opposite position on the surface of static contact upper side, and the bottom of fixed baffle is contacted with the outer wall of first arc-extinguishing chamber. By setting two arc-extinguishing chamber arrangement and positioning, the breaking capacity, safety reliability and service life of moulded case circuit breaker are significantly improved.

The invention relates to the technical field of circuit breakers, and discloses a grounding type circuit breaker, the circuit breaker comprises a moving contact, a static contact, a handle, a cover body and an output end, a grounding part and a first connecting piece are arranged in the circuit breaker, one end of the first connecting piece is connected with the moving contact, and after the moving contact is separated from the static contact in the opening process, the grounding part is connected with the first connecting piece. And the moving contact drives the first connecting piece to extrude the grounding part, so that the grounding part is contacted with the output end to be grounded. According to the grounding type circuit breaker, in the operation process of the circuit breaker, the moving contact is connected with the output end, then when the moving contact is subjected to opening operation, the grounding power rod and the grounding force transmission rod are used for controlling the grounding component to complete grounding, safety when a switch is switched off is guaranteed, it is guaranteed that no current exists in a circuit after the switch is switched off, and when the switch is switched on, the grounding component is not damaged. The grounding reset lever is firstly toggled, so that the grounding reset pinch bar pushes the grounding force transmission rod, and the grounding function of the circuit breaker is relieved.

The invention provides a static contact of an electric switch, which at least comprises a conductive connecting piece, a contact point and a conductive body, the contact point is welded on the conductive body or the conductive connecting piece, the conductive body and the conductive connecting piece are arranged in a split or integrated manner, and the contact point is welded on the conductive body or the conductive connecting piece based on the total volume of the conductive body. The volume ratio of the conductor made of the iron material in the conductor is 30%-100%, or the material of the conductor at least contains more than 30% of the iron material in volume ratio. The invention also provides an electromagnetic release comprising the static contact. The invention relates to a static contact of an electric switch, which is applied to the electric switch, because an electric conductor containing an iron material is arranged in a main loop, part of arc energy is consumed on the iron material when the electric switch is switched off by utilizing the positive temperature coefficient characteristic of the iron material, so that the current limiting coefficient of the electric switch is reduced; the current limiting performance of the electrical switch can be improved.

The invention relates to an arc extinguishing structure for a circuit breaker and the circuit breaker. The arc extinguishing structure for the circuit breaker comprises an arc extinguishing chamber (10) and a shell (20). The arc extinguish chamber (10) comprises a plurality of arc extinguish pieces (11) which are separated from one another, and is provided with a front end close to the arc generation area and a rear end far away from the arc generation area. The shell (20) is provided with an inner cavity for containing the arc chamber (10). Wherein the inner cavity comprises a backflow area (21) and an open area (22), the backflow area (21) is closer to a static contact of the circuit breaker than the open area (22), the backflow area (21) is not communicated with the outside of the inner cavity of the shell (20), and the open area (22) is communicated to the outside of the inner cavity of the shell (20) through an exhaust channel.

The invention discloses an operating mechanism and a circuit breaker, the operating mechanism comprises a handle, a contact support and a moving contact, the handle is rotatably installed on a base, a connecting rod is also arranged between the handle and the contact, the moving contact is installed on the contact support, a first spring is also arranged between the contact support and the moving contact, and a second spring is also arranged between the contact support and the moving contact. The moving contact is under the action of the spring force of the first spring, and the moving contact is always in contact with the contact support without external force. The circuit breaker further comprises a lock catch, the lock catch is installed on the contact support, a second spring is further installed on the lock catch, the connecting rod makes contact with the lock catch and the contact support through the spring acting force of the second spring, and the lock catch is used for achieving the functions of instantaneous tripping, overload tripping and circuit breaker linkage. Compared with the prior art, the mechanism combines a plurality of parts into one part, the reliability of the circuit breaker is reduced by reducing the parts, the manufacturing cost of part molds is reduced, and the assembly efficiency of the circuit breaker is improved.

A switch belongs to the technical field of low-voltage apparatuses. Comprising a main shaft, a shell and a contact system, the contact system is arranged in the shell, the main shaft is rotationally arranged on the outer side of the shell, a swing piece is installed on the main shaft, the swing piece is in linkage with a moving contact of the contact system through hinge joint, and the contact system is arranged in the shell. At least one of the pendulous reeds is provided with an impact end, and when the main shaft rotates to a switching-off in-place position, the impact end impacts the housing to prevent the main shaft from continuously rotating along the switching-off direction. The utility model has the advantages that the impact end is arranged on the swing sheet of the main shaft connected with the moving contact, the number of parts is reduced, and the structure is simplified.

A trip device is disclosed. The trip device according to an embodiment of the present invention comprises an adjustment crossbar. The adjustment crossbar is in contact with or is spaced apart from a shooter and can open or close a breaker having the trip device. The adjustment crossbar is formed by coupling a fixed crossbar and a movable crossbar. The movable crossbar is slidably coupled to the fixed crossbar. The shooter is in contact with the fixed crossbar. Therefore, regardless of the movement of the movable crossbar, the contact between the shooter and the fixed crossbar can be maintained.

The utility model discloses a static contact assembly which comprises a static contact and a magnetic blow-out assembly installed on the static contact. The magnetic blow-out assembly comprises a support installed on the static contact, a magnetic group is installed in the support, and magnetic repulsive force generated by the magnetic group is used for blowing away electric arcs generated at the static contact. In conclusion, the magnetic blow-out assembly is arranged on the static contact, so that when the electric arc impacts the static contact, the magnetic blow-out assembly generates electromagnetic repulsive force to prevent the electric arc from directly striking the static contact, and meanwhile, the generation of the magnetic repulsive force can also push the electric arc to float, so that the direct impact of the electric arc on the static contact is further reduced, and the service life of the static contact is further prolonged. On the basis, although the equipment is simple in structure, the processing difficulty of the static contact is not increased through the simple structure, and the service life of the static contact can be effectively prolonged.

The application relates to the low-voltage electrical field and particularly relates to a circuit breaker, a first contact system of which comprises a first moving contact mechanism, a first static contact and a second static contact arranged on the two sides of the first moving contact mechanism respectively, a first arc extinguishing system comprising a first arc extinguishing chamber and a second arc extinguishing chamber, a button mechanism, an operating mechanism and the first moving contact mechanism being sequentially and drivingly connected; the button mechanism, the operating mechanism and a first incoming line end are sequentially arranged along the length direction of the circuit breaker and are all located on one side in the width direction of the circuit breaker; the first outgoing line end, the second arc extinguishing chamber, the first moving contact mechanism and the first arc extinguishing chamber are sequentially arranged along the length direction of the circuit breaker and are located on the other side in the width direction of the circuit breaker, the first outgoing line end and the button mechanism are located on one end in the length direction of the circuit breaker, and the first arc extinguishing chamber and the first incoming line end are located on the other end in the length direction of the circuit breaker; the circuit breaker is reasonable in layout and compact in structure.

The utility model belongs to the technical field of circuit protection, and particularly relates to an anti-overload structure of micro-integrated equipment, which comprises an overload protector body, a reset rod and connecting contact pieces, the reset rod is movably inserted into an inner cavity of the overload protector body, the connecting contact pieces are arranged at the bottom of the overload protector body and are symmetrically arranged, and the reset rod is movably inserted into the inner cavity of the overload protector body. The overload protector comprises an overload protector body, an overload detection iron sheet is arranged on the surface of the overload protector body, a resistance heating wire is movably arranged on the surface of the overload protector body, the two ends of the resistance heating wire are connected with mounting seats, mounting grooves are formed in the positions, located at the two ends of the overload detection iron sheet, of the surface of the overload protector body, and the mounting seats are fixed in the mounting grooves through countersunk bolts. According to the overload protector, the resistance heating wire is installed on one side of the overload detection iron sheet, the resistance heating wire generates heat after being electrified, the heat is transmitted to the overload detection iron sheet to enable the overload detection iron sheet to deform, and therefore overload detection can be actively carried out on the overload protector to detect whether the function of the overload protector is normal or not.

A system includes a circuit breaker and a switching module with a first module terminal for electrically connecting the switching module to an electrical circuit, and a second module terminal connected in electrical series with a first terminal of the circuit breaker. A switching device of the switching module is connected in electrical series between the first and second module terminals and is configured to switch between an ON state for allowing electrical current through the electrical circuit and an OFF state for opening the electrical circuit to stop current flow therethrough. The circuit breaker has a first housing that houses the breaker mechanism therein. The switching module has a second housing that houses the switching device therein. The second housing can be mounted to the first housing. The first and second housings together can be configured to fit in a physical envelope of a molded case circuit breaker (MCCB).

The invention provides a circuit breaker which comprises a shell and an arc extinguish chamber, an N-pole exhaust channel and an L-pole exhaust channel are arranged in the shell, the shell is provided with an exhaust port, the exhaust end of the N-pole exhaust channel and the exhaust end of the L-pole exhaust channel are communicated with the exhaust port, and the N-pole exhaust channel and the L-pole exhaust channel are each provided with at least one circulation cavity. And the arc extinguish chambers are respectively arranged in the N-pole exhaust channel and the L-pole exhaust channel. According to the circuit breaker provided by the invention, by adopting the double-exhaust structure of the N-pole exhaust channel and the L-pole exhaust channel and the arrangement of the circulating cavity, the arc extinguishing and exhaust efficiency is improved, the exhaust efficiency is improved, the breaking capacity of the circuit breaker is further improved, the use efficiency and use safety of the circuit breaker are improved, and the service life of the circuit breaker is prolonged. The problem that the use safety and the service life of a product are affected due to poor breaking capacity of a circuit breaker in the prior art is solved.

A circuit breaker comprises a shell, and a manual driving mechanism, an operating mechanism, a contact mechanism and a wiring structure which are arranged in the shell, the manual driving mechanism and the wiring structure are respectively arranged at two opposite ends of the shell along a first direction, and two plugging mechanisms of the wiring structure are arranged side by side at an interval along a second direction. The operating mechanism is arranged between the manual driving mechanism and the wiring structure, two arc extinguishing mechanisms which are arranged side by side along a third direction are arranged between the operating mechanism and the wiring structure, two moving contacts and two static contacts are arranged between the operating mechanism and the two arc extinguishing mechanisms, and the two static contacts correspond to the two moving contacts respectively. The two arc extinguishing mechanisms correspond to the two static contacts respectively, the first direction, the second direction and the third direction are perpendicular to each other, back-in and back-out can be achieved, and the circuit breaker has the advantages of being compact in structure and convenient to operate.

The invention provides a circuit breaker contact system parameter adjusting method and device and electronic equipment, and relates to the technical field of circuit breakers, and the method comprises the steps: obtaining an arc contact opening range, a main contact opening range and a critical short-circuit current interval of a to-be-adjusted circuit breaker; calculating the ratio of the arc contact opening distance to the main contact opening distance to obtain a first ratio; the first proportion is adjusted in a first preset proportion interval, the to-be-adjusted circuit breaker performs a breaking test with the target short-circuit current as the short-circuit current according to the value of the first proportion, and the target proportion of the to-be-adjusted circuit breaker is determined according to the arcing time or breaking times obtained through the breaking test, the arc contact opening distance and the main contact opening distance of the to-be-adjusted circuit breaker are adjusted according to the target proportion; the first preset proportion interval is 1.2-1.4, and the target short-circuit current is any value in the critical short-circuit current interval. By adjusting the opening distance of the arc contact and the opening distance of the main contact, the breaking reliability of the circuit breaker in a rated short-circuit breaking current range is improved.

The invention relates to an alarm mechanism of a circuit breaker and an oil-immersed circuit breaker. The alarm mechanism comprises an alarm rack, an alarm conductive assembly, an alarm push-pull rod and a lifting cross rod; the alarm conductive assembly is installed on the alarm rack in an electric insulation mode. The alarm push-pull rod can move on the alarm rack in a resettable manner; the alarm push-pull rod is provided with a V-shaped opening, and the V-shaped opening is provided with a guide inclined wall; the lifting cross rod is limited on the alarm rack in a lifting manner and transversely extends into the V-shaped opening; the alarm push-pull rod drives the guide inclined wall to move, and the guide inclined wall drives the lifting cross rod to move to make contact with the alarm conductive assembly, so that the alarm conductive assembly is conductively connected with the lifting cross rod. According to the scheme, the transmission structure of the circuit breaker alarm device during alarming is simplified, the circuit breaker alarm device can be more compact, and the problem that the occupied space is large due to the fact that the transmission structure of an existing circuit breaker alarm device is complex is solved.

Disclosed are an arc extinguishing unit, a circuit breaking unit, and an air circuit breaker including the same. The present disclosure provides an arc extinguishing unit, a circuit breaking unit, and an air circuit breaker, including: side plates spaced apart from each other and disposed to face each other; a plurality of grids disposed between the side plates, spaced apart from each other, and coupled to the side plates, respectively; and a grid cover located above the grid and covering the grid, wherein the grid includes a grid leg extending downward to surround from both sides a protruding contact disposed to extend upward from a movable contact; and a first protective part formed to surround at least a portion of the grid leg at a lower portion of the grid leg.