Patent Publication Number: US-9847603-B1

Title: Grounding system and method for providing electrical contact between two components

Description:
TECHNICAL FIELD 
     The application relates generally to grounding systems and, more particularly, to adjustable grounding systems, and method for ensuring electrical contact between two components. 
     BACKGROUND OF THE ART 
     Grounding systems are usually used to ensure constant and reliable electrical continuity between two components, for example two metal components, without the use of fixed wires and/or connectors, or hard electrical connections. In some situation it is necessary to maintain some variability and flexibility in the distance between the two components. 
     Particular grounding systems allowing distance variability between two components have been developed. Some known systems provide, for example, socket connectors to interconnect two electric components. 
     Commonly used systems above are however typically not adapted to maintain hermetic sealing between the two components, or to allow angular flexibility so that the components are easily and safely assembled and disassembled. 
     SUMMARY 
     In one aspect, there is provided a grounding system for electrically connecting a first component to a second component, the grounding system comprising: a connection plate having a hole defined therein, the connection plate configured to be in electrical contact with the first component; a receptacle plate mounted to and in electrical contact with the connection plate, the receptacle plate having a receptacle opening defined therethrough, the receptacle opening aligned with and larger than the hole of the connection plate; and a plunger assembly including: a pin having a first end configured to be electrically connected to the second component and an opposed second end, the second end receivable through the receptacle opening and through the hole of the connection plate; and an electrical connector retained in electrical contact with the pin, the electrical connector receivable in the receptacle opening and configured to be in electrical contact with a circumferential surface of the receptacle opening, the electrical connector being movable along the pin and biased toward the second end, the electrical connector having an outer dimension greater than that of the hole of the connection plate so as to be prevented from passing therethrough. 
     In another aspect, there is provided a grounded box and lid assembly comprising: a receptacle plate in electrical contact with a first one of the box and the lid, the receptacle plate having a receptacle opening defined therethrough, the receptacle opening aligned with and larger than a hole defined in the first one of the box and the lid; a pin having a first end connected to and in electrical contact with a second one of the box and the lid, the pin having an opposed second end, the second end receivable through the receptacle opening and through the hole; and an electrical connector retained in electrical contact with the pin, the electrical connector being receivable in the receptacle opening and configured to be in electrical contact with a circumferential surface of the receptacle opening, the electrical connector being movable along the pin and biased toward the second end, the electrical connector having an outer dimension greater than that of the hole so as to be prevented from passing therethrough. 
     In a further aspect, there is provided a method of providing electrical contact between first and second relatively movable components, the method comprising: moving a pin in electrical contact with the first component through a receptacle opening defined in a receptacle plate in electrical contact with the second component as the first and second components are moved relative to each other; moving an electrical connector along the pin while maintaining the electrical connector in the receptacle opening, the electrical connector being in electrical contact with the pin and with the receptacle plate. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Reference is now made to the accompanying figures in which: 
         FIG. 1 a    is a schematic tridimensional view of a grounding system in accordance with a particular embodiment, in an extended configuration; 
         FIG. 1 b    is a schematic cross-sectional view of the grounding system of  FIG. 1   a;    
         FIG. 1 c    is a schematic, tridimensional cross-sectional view of the grounding system of  FIG. 1 a   , in an angled configuration; 
         FIG. 2 a    is a schematic tridimensional view of the grounding system of  FIGS. 1 a -1 b   , in a compressed configuration; 
         FIG. 2 b    is a schematic cross-sectional view of the grounding system of  FIG. 2   a;    
         FIG. 3 a    is a schematic side view of a plunger assembly of the grounding system of  FIGS. 1 a  to 2 b   , in accordance with a particular embodiment; 
         FIG. 3 b    is a schematic tridimensional view of the plunger assembly of  FIG. 3   a;    
         FIG. 4 a    is a schematic side view of a plunger assembly of the grounding system of  FIGS. 1 a  to 2 b    in accordance with another particular embodiment, including an annular seal; 
         FIG. 4 b    is a schematic tridimensional view of the plunger assembly of  FIG. 4   a;    
         FIG. 5  is a schematic exploded tridimensional view of an alignment guide in accordance with a particular embodiment, which may be used with the grounding system of  FIGS. 1 a    to  2   b;    
         FIG. 6 a    is a schematic cross-sectional view of the alignment guide and grounding system of  FIG. 5  installed in a box and lid assembly, with the grounding system in an extended configuration and with the lid parallel to a surface of the box; 
         FIG. 6 b    is a schematic cross-sectional view of the assembly of  FIG. 6 a   , with the grounding system in the extended configuration and with the lid being titled with respect to the surface of the box; and 
         FIG. 6 c    is a schematic cross-sectional view of the assembly of  FIG. 6 a   , with the grounding system in a compressed configuration and with the lid parallel to a surface of the box. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 a  to 2 b   , there is provided a grounding system  10  for electrically connecting a first component  11  to a second component  14 . The grounding system is used to provide electrical continuity between two surfaces that have to maintain distance variability/flexibility between them, without using any connection (wire, connectors . . . ). Hermetic sealing may also be ensured using the present grounding system  10 . The first and second components  11 ,  14  are distant of a variable distance, and the grounding system  10  is adjustable between an extended configuration wherein the first and the second components  11 ,  14  are at a predetermined maximal distance D 1  from each other (see  FIGS. 1 a -1 b   ) and a compressed configuration wherein the first and the second components are at a distance D 2  smaller that the maximal distance D 1  (see  FIGS. 2 a -2 b   ). 
     The predetermined maximal distance is set as a function of the distance that can be allowed between the first and second components  11 ,  14 . For example, if a compressible gasket (not shown) is provided between the first and second components  11 , for hermetic sealing, the predetermined maximal distance may be set so that the compressible gasket is not extended further than its maximal extension. 
     As can be best seen in  FIGS. 1 b  and 2 b   , the grounding system  10  includes a connection plate  12  having a hole  15  defined therein. The connection plate  12  is in electrical contact with the first component  11 . In a particular embodiment the connection plate  12  is a delimited area of the first component  11 , i.e. is an integral part of the first component  11 . Alternately, the connection plate  12  may be defined separately and attached to the first component  11  so as to be in electrical contact therewith. The connection plate  12  has a surface  16  facing a surface  17  of the second component  14 . The facing surface  17  of the second component  14  may be a delimited area of the second component  14  or may be defined by a separate element (e.g., plate) fastened to and in electrical contact with the second component  14 . The surface  16  of the connection plate  12  and the facing surface  17  of the second component  14  are distant from each other of a variable distance, and may further be parallel relative to each other. 
     It is understood that in the present disclosure, including claims, the term “plate” includes, but is not restricted to, a thin structure having a constant thickness. Various alternate configurations are possible. 
     Still referring to  FIGS. 1 b  and 2 b   , the grounding system  10  includes a receptacle plate  18  that is mounted to and in electrical contact with the connection plate  12 . The receptacle plate  18  may be mounted using any suitable type of fastener allowing electrical continuity. In the embodiment shown, metal screws are used to fasten the receptacle plate  18  in electrical contact to the connection plate  12 . The receptacle plate  18  includes an inner surface  20  and an outer surface  22  opposite to the inner surface  20 . The receptacle plate  18  is mounted to the connection plate  12  so that the inner surface  20  is in electrical contact with the surface  16  of the connection plate  12 . The receptacle plate  18  has a thickness T 1  defined between the inner surface  20  and the outer surface  22 . 
     The receptacle plate  18  has an opening  24  defined therein. The receptacle opening  24  is defined in both the inner and outer surfaces  20 ,  22 , and through the thickness T 1  of the receptacle plate  18 . The receptacle opening  24  has a circumferential surface  26 , which in the embodiment shown is cylindrical. 
     The receptacle opening  24  is aligned with the hole  15  of the connection plate  12 , so that the receptacle opening  24  and the hole  15  are superposed. The receptacle opening  24  has a diameter larger than the diameter of the hole  15  so that the opening  24  is also aligned with an annular portion of the surface  16  that surrounds the hole  15 . In a particular embodiment the opening  24  and the hole  15  are circular. In the embodiment shown, the opening  24  and the hole  15  are concentric. 
     Still referring to  FIGS. 1 b  and 2 b   , the grounding system  10  also includes a plunger assembly  30  that provides the electrical connection between the second component  14  and the receptacle plate  18 , and therefore between the second component  14  and the connection plate  12  and first component  11 . The plunger assembly  30  is mounted to and in electrical contact with the second component  14  and protrudes towards the receptacle plate  18  and the first component  11 . 
     Referring to  FIGS. 3 a -3 b   , the plunger assembly  30  includes a pin  32  mounted by a first end  34  in electrical contact to the second component  14 . In a particular embodiment, the pin  32  is in direct electrical contact with the second component  14 . For example, the pin  32  can be mounted to the second component  14  using pressure fit insertion. The pin  32  may also be mounted using an adaptor (such as an additional metal plate) configured to secured the first end  34  of the pin  32  in electrical contact to the second component  14 . The pin  32  has a second end  36  opposite the first end  34 . The pin  32  extends toward the receptacle plate  18  and has a total length L 1  ( FIG. 3 a   ) defined between the first end  34  and the second end  36 . The length L 1  of the pin  32  is selected to allow the predetermined maximal distance D 1  between the first and the second components  11 ,  14  and is at least equal to the distance D 1 . The pin  32  is sized relative to the receptacle opening  24  of the receptacle plate  18  and the hole  15  of the connection plate  12  so that the second end  36  of the pin  32  can extend through both the receptacle opening  24  and the hole  15 . In a particular embodiment the pin  32  is a cylindrical pin and the second end  36  is defined by a retaining screw. 
     The plunger assembly  30  further includes an electrical connector used to provide electrical contact between the receptacle plate  18  and the pin  32 ; the electrical connector may be any element suitable to transmit electricity between the receptacle plate  18  and the pin  32 . In the embodiment shown, the electrical connector is an annular coil  38  made of metal. The coil  38  is received in the receptacle opening  24  and includes a central opening for receiving the pin  32 . Therefore, the coil  38  surrounds the pin  32  over a section of a lateral surface of the pin  32 . The coil  38  is movable along the length L 1  of the pin  32  but prevented from moving passed the second end  36  of the pin  32  for example by a stop member  42  as will be further detailed below. The coil  38  is biased toward the second end  36  of the pin  32 , as will be further described below. 
     Referring to  FIGS. 1 b  and 2 b   , it can be seen that the coil  38  has an outer dimension (outer diameter) that is larger than that of the hole  15  in the connection plate  12  so as to be prevented from passing therethrough, and is therefore retained within the receptacle opening  24  when the first and second components get closer to each other; abutment of the coil  38  against the surface  16  of the connection plate  12  prevents the coil  38  from following the pin  32  through the hole  15  of the connection plate  12 . The coil  38  has a circumferential outer surface that is in electrical contact with the circumferential surface  26  of the receptacle opening  24 . The coil also has a circumferential inner surface in electrical contact with the pin  32 . In a particular embodiment, the coil  38  is retained in the receptacle opening  24  in a compressed configuration. In its uncompressed configuration, the outer diameter of the coil  38  is greater than an inner diameter of the receptacle opening  24 , so as to be compressed by and against the circumferential inner surface  26  of the receptacle opening  24 . In a particular embodiment, this improves the reliability of the contact between the coil  38  and the pin  32 , as well as between the coil  38  and the circumferential inner surface  26  of the receptacle opening  24 . The coil  38  may also be received in an uncompressed configuration, wherein the outer diameter of the coil  38  is equal to the inner diameter of the receptacle opening  24 , and where contact of the coil  38  with both the pin  32  and the circumferential inner surface  26  of the receptacle opening  24  is maintained in the uncompressed configuration. 
     In the embodiment shown, the coil  38  has a thickness T 2  ( FIG. 3 a   ) that is equal or less than the thickness of the receptacle plate T 1  ( FIGS. 1 b , 2 b   ). Therefore, the coil  38  is movable (e.g. slidable) along the pin  32  within the receptacle opening  24  while remaining in the receptacle opening  24 . 
     In a particular embodiment, the grounding system  10  is configured to allow the plunger assembly  30  to have some leeway in terms of angular movement within the receptacle opening  24 . The receptacle plate has a thickness T 1  that is low enough to reduce the risk of breaking or bending the plunger assembly  30  if the facing surfaces of the first and second components are moved from being parallel to each other, as illustrated by  FIG. 1   c.    
     As illustrated in  FIGS. 1 b , 2 b  and 3 b   , in a particular embodiment, the grounding system  10  includes a first stop member  40  preventing the coil  38  from sidling out of the receptacle opening  24  and applying the bias to the coil  38 . The first stop member  40  includes a hole defined therein for receiving the pin  32 , and is movable along the pin  32 . The first stop member  40  is located between the second component  14  and the outer surface  22  of the receptacle plate  18  and has an outer dimension which is greater than the receptacle opening  24 , so as to be prevented from passing therethrough and at least partially cover the receptacle opening  24  around the pin  32 . The first stop member  40  may have various shapes, as long as it extends across the space defined between the lateral surface of the pin  32  and the circumferential surface  26  of the receptacle opening  24  adjacent the outer surface  22  of the receptacle. For example, in the embodiment shown, the receptacle opening  24  is a circular opening and the pin  32  is a cylindrical pin, and the first stop member  40  is an annular washer having an inner diameter slightly larger than the diameter of the pin  32  and an outer diameter larger than the diameter of the receptacle opening  24 . When the first stop member  40  is in contact with the outer surface  22  of the receptacle plate  18 , the first stop member  40  retains the coil  38  within the receptacle opening  24 . 
     In a particular embodiment, the coil  38  is prevented from moving out of the second end  36  of the pin  32  by the second stop member  42 . The second stop member  42  is connected to the second end  36  of the pin  32 , for example electrically connected thereto, and configured to pass through both the hole  15  of the connection plate  12  and the receptacle opening  24  while preventing the coil  38  from moving out of the pin  32 . In the embodiment shown, the second stop member  42  is an annular washer secured to the second end  36  of the pin  32  and having an outer diameter larger than an inner diameter of the coil  38  but smaller than the hole  15  in the connection plate  12 . The second stop member  42  is secured to the second end  36  of the pin  32 , by a retaining screw for example. 
     In the embodiment shown, the coil  38  is sandwiched between the first stop member  40  and the second stop member  42  when the grounding system  10  is in the extended configuration (see  FIG. 1 b   ). 
     In a particular embodiment, as illustrated in  FIGS. 1 b , 2 b  and 3 b   , the grounding system  10  further includes a biasing member  44  located between the first stop member  40  and the second component  14 , and biasing the first stop member  40  toward the second end  36  of the pin and the bottom surface  22  of the receptacle plate  18  to bias the coil  38  toward the second end  36  of the pin  32 . In the embodiment shown, the biasing member is a spring  44 . The spring  44  exerts a force on the first stop member  40  toward the receptacle plate  18 , so that the first stop member  40  remains in continuous contact with the bottom surface  22  of the receptacle plate  18  to retain the coil  38  within the receptacle opening  24  when the pin  32  extends through the opening  24 . In the embodiment shown, the spring  44  is configured to surround the pin  32 . For example, the spring  44  surrounds the pin  32  in a spiral fashion and extends from the second component to the first stop member  40 . 
     Alternately, the biasing member  44  may bias the coil  38  within the receptacle opening  24  directly, i.e. without the need for a stop member therebetween. However, in a particular embodiment, the use of the stop member allows to limit the biasing force applied to the coil  38 , which may prevent the coil  38  from being damaged by the biasing force. 
     Referring to  FIGS. 4 a -4 b   , a plunger assembly  130  according to another embodiment is shown, which may be used in the grounding system  10  and is similar to the plunger assembly  30  described above; similar elements are identified by the same reference numerals and will not be described further herein. In this embodiment however, the plunger assembly  130  further includes a seal  46  located between the outer surface  22  of the receptacle plate  18  and the first stop member  40 . The seal  46  engages the pin  32  to provide hermetic sealing between the bottom surface  22  of the receptacle plate  18  and the first stop member  40  biased thereagainst. The seal  46  is movable along the pin  32 . In the embodiment shown, the seal  46  is an annular seal  46  receiving the pin  32  in a central opening thereof and having an outer diameter larger than the receptacle opening  24 . 
     In a particular embodiment, the seal  46  is an annular rubber washer. The inner diameter of the annular rubber washer is slightly smaller than the diameter of the pin  32  to create a seal between the annular rubber washer and the pin  32  while allowing the annular rubber washer to slide along the length L 1  of the pin  32 . 
     Referring back to  FIGS. 1 a -1 b   , in a particular embodiment, when the grounding system  10  is in the extended configuration, the first and second components  11 ,  14  are at maximal distance D 1  from each other while still being in electrical contact with each other through the grounding system  10 . The spring  44  pushes the first stop member  40  toward and against the outer surface  22  of the receptacle plate  18  to retain the coil  38  in the receptacle opening  24 . Because the diameter of the second stop member  42  is smaller than the hole  15  in the connection plate, the second end  36  of the pin  32  passes through the hole  15  in the connection plate and the receptacle opening  24 . The coil  38  is pushed toward the second end  36  of the pin  32  against the second top member  42 , which is also received in the receptacle opening  24 . The coil  38  is therefore sandwiched between the first and second stop members  40 ,  42 . 
     When the first and second components  11 ,  14  are brought closer to each other, the plunger assembly  30  is pushed further into the receptacle opening  24 . The coil  38  is retained by the surface  16  of the connection plate  12  and slides along the pin  32  while remaining in the receptacle opening  24 . The first stop member  40  is pushed toward the second component  14  by the outer surface  22  of the receptacle plate  18  and the spring  44  is progressively compressed. 
     In the compressed configuration, illustrated in  FIGS. 2 a -2 b   , the first and second components  11 ,  14  are at a distance D 2  from each other, with D 2  being smaller than D 1 . The first stop member  40  and the spring  44  are held back by the outer surface  22  of the receptacle plate  18 , so as to prevent the spring  44  from exerting the biasing force on the coil  38 . The coil  38  remains within the receptacle opening  24  due to the first stop member  40 , without being crushed or damaged by the spring  44 . It can be seen that, if the thickness of the coil T 2  is smaller than the thickness of the receptacle opening T 1 , the coil  38  is not sandwiched between the first and second stop members  40 ,  42 , and a space remains below the coil  38 . 
     In a particular embodiment and referring to  FIG. 1 c   , the configuration of the grounding system  10  allows for some angular leeway between the two components  11 ,  14 , particularly when they are at the maximum distance (D 1 ) allowing for an electrical connection to be maintained, i.e. when the assembly is uncompressed. This may allow, for example, for some misalignment upon engaging the two components  11 ,  14  together, while still allowing electrical contact therebetween through the grounding system  10 . 
     The angular leeway is defined by the interactions of the pin  32  and its second end  36  (e.g. retaining screw), as well of the second stop member  42 , with the receptacle opening  24  in the receptacle plate  18 , i.e. by the difference between the outer diameters of the pin  32 , second end  36  and second stop member  42 , and the inner diameter of the surface  26  of the receptacle opening  24 . As the pin  32  is tilted with respect to the receptacle plate  18 , the maximum leeway will be reached when either the second end  36  of the pin (e.g. retaining screw) and/or the outside diameter of the second stop member  42  make contact with the surface  26  of the receptacle opening  24 , or when the pin  32  makes contact with the surface  26  of the receptacle opening  24 . 
     In a particular embodiment, the first stop member  40  is defined by a washer having a sufficiently large inner diameter so as to allow the washer to tilt with respect to the pin  32  and allow for contact between the first stop member  40  and the outer surface  22  of the receptacle plate  18  to be maintained when the pin  32  is tilted with respect to the receptacle plate  18 , and in a particular embodiment at the maximum leeway position. 
     In a particular embodiment, the thickness T 1  of the receptacle plate  18  is selected to be at least large enough to allow for the coil  38  to remain within the receptacle opening  24  when the pin  32  and receptacle plate  18  are relatively tilted at the maximum leeway position. In a particular embodiment, the thickness T 1  of the receptacle plate  18  is at the minimum value allowing for the coil  38  to remain within the receptacle opening  24  when the pin  32  and receptacle plate  18  are relatively tilted at the maximum leeway position 
     In a particular embodiment, the maximum leeway position defines an angle α of from 14 to 15 degrees between the opposed surfaces  16 ,  17  of the components. Other values are also possible. 
     In a particular embodiment, since the plunger assembly  30  protrudes from the second component  14 , it may be susceptible to being damaged. For example, the plunger assembly  30  can be snagged or hit by other bodies. In addition, the grounding system  10  may have a small size relative to the first and second components, so that visibility of the grounding system  10  is reduced, and proper alignment of the plunger assembly  30  with the receptacle opening  24  may be difficult to ensure. 
     Referring to  FIGS. 5 and 6   a  to  6   c , in a particular embodiment, the grounding system  10  further includes an alignment guide  48  is configured to protect the plunger assembly  30  and to help alignment of the plunger assembly  30  with the receptacle opening  24  and the first component hole  15 . In the embodiment shown, the alignment guide  48  is provided proximate to the plunger assembly  30  and partially wraps around the plunger assembly  30 , as opposed to having the plunger assembly  30  passing through the alignment guide  48 . The plunger assembly  30  and receptacle plate  18  are fastened directly to respectively the second component  14  and the first component  11 . 
     The alignment guide  48  includes female element  50  and a male element  52 , one on each of the first and second components  11 ,  14 . A first one of the female and male elements  50 ,  52  is provided on the first component  11 , for example on or adjacent the connection plate  12 , and the second one of the female and male elements  50 ,  52  is provided on the surface  17  of the second component  14 . In the embodiment shown the male element  52  is provided on the second component  14  proximate the plunger assembly  30 , and the female element  50  is provided on the surface  16  of the connection plate  12  proximate the receptacle plate  18 . 
     The female element  50  and the male element  52  are selectively engageable with one another, and accordingly have complementary shapes. In the embodiment shown, the male and female elements  52 ,  50  have complementary semi-spheroid shapes. 
     In a particular embodiment, as illustrated in  FIG. 5 , the semi-spheroid shaped male element  52  is mounted to the second component  14  and wraps around the plunger assembly  30  while the female element  50  is mounted to the first component  11  and defines a semi-spheroid recipient (or “cup”) for receiving the male element  52  therein. The male element  52  extends from the second component  14  a distance L 2  which is larger than the length L 1  of the pin  32  and protects the plunger assembly  30  along its entire length L 1 . The male element  52  provides a lateral obstruction to potential hits from other bodies due to the wrap-around shape. In a particular element, the male element  52  protruding a distance larger than the length of the plunger assembly  30  may allow improved visual detection of misalignment between the plunger assembly  30  and the hole  15  in the first component. 
     As can be seen in  FIG. 5 , the male element  52  has a full surface free of holes. In a particular embodiment, the absence of holes allows to avoid air leaks which may compromise the hermetic sealing between the first and second components. 
     The alignment guide  48  also allows for leeway in term of angular movement and gradual alignment. As the first and second components come closer together, the alignment becomes more precise. 
     In a particular embodiment, the alignment guide  48  and the male and female element  52 ,  50  composing the same are made in ABS material. In addition, the male and female  52 ,  50  elements may be manufactured using 3D printing. 
     The grounding system  10  may be used in any application where a box or case has to be mated with another box or case or with a lid, for example on a fume extractor to be mated to another plenum box or to a lid. It is understood that further reference to a plenum box and a lid would also apply to two plenum boxes, or any other mating components that have to remain in electrical contact. Compressible foam gaskets may be provided between the lid and the plenum box that compress to varying degrees during operation as the negative pressure in the system changes. 
     In the particular embodiment shown, the grounding system  10  is used on a modular fume extractor box and lid. The lid of the modular fume extractor is removable by the end-user. However, it cannot be expected that the end-user will remove or install the lid in a perfectly straight up and down path. An angular path or curved path is expected. In addition, electrical continuity is required between the box and the lid each defining a plenum while allowing compression of a gasket therebetween to ensure proper air sealing between the box and the lid. The compression is variable depending on the clamping pressure applied when securing the box and the lid together or depending on the vacuum pressure between the box and the lid which might pull the box and the lid closer together as negative pressure increases. 
     As can be seen on  FIGS. 5 and 6 , the plunger assembly  30  and the semi-spheroid male element  52  of the alignment guide  48  are mounted to the bottom of the lid  54 . The receptacle plate  18  and the female element  50  of the alignment guide  48  are mounted to the top of the box  56 . The connection plate  12  is an integral part of the box  56 . It is understood that alternately, the plunger assembly  30  may be mounted to the box  56  and the receptacle plate  18  to the lid  54 . 
     In a particular embodiment, upon initial placement of the lid  54  onto the box  56 , the male element  52  protects the plunger assembly  30  even if the lid  54  is placed onto the box  56  with force and with misalignment. If the lid  54  is misaligned with respect to the grounding system  10 , it will be visually detectable due to the unparalleled seating of the lid  54  onto the box  56  which is caused by the male element  52  not sitting in the female element  50 . Once the male element  52  is aligned with the female element  50 , the plunger assembly  30  gradually aligns with the receptacle plate  18  of the grounding system  10 . The grounding system  10  also allows the lid  54  to be moved along an angular or curved path without the risk of bending or breaking the plunger assembly  30 . The ground circuit is automatically defined and electrical continuity is provided once the lid  54  is installed. 
     The grounding system  10  maintains electrical continuity between the lid  54  and the box  56  despite the change in the distance between them and also preserves the hermetic seal between the lid  54  and the box  56 . The lid  54  can be installed and removed by placing or lifting the lid  54  without having to be gentle or precise or maintaining a perfectly straight up/down path. Indeed, because of the alignment guide  48 , the plunger assembly  30  and the receptacle plate  18  of the fume extractor are aligned. 
     In a particular embodiment and in use, the grounding system  10  thus allows for electrical contact between two relatively movable components to be maintained as the two components are moved relative to each other. The two components are distant of a variable distance, which maximal value is D 1 . The two components may be, for example, two plenums boxes of a fume extractor that have to be mated with each other, or a plenum box and a lid to be installed on the plenum box. 
     The receptacle plate  18  is mounted to and in electrical contact with the connection plate  12  configured to be in electrical contact with the first one of the two components. The receptacle plate  18  may be mounted using metal screw or any other type of fastening elements allowing electrical continuity between the receptacle plate and the first component. 
     The pin  32  is mounted to and in electrical contact with the second one of the two components. The pin  32  has a length a least equal to the predetermined maximal distance D 1  to allow the two components to be distant of D 1  while ensuring electrical continuity. The pin  32  may be mounted by pressure fit insertion or any other type of fastening method allowing electrical continuity between the pin  32  and the second component. The pin is sized to be received in the receptacle opening  24  and the hole  15  of the connection plate  12 . 
     Electrical contact is provided between the pin and the receptacle plate  18 , using a connector, such as the coil  38 , in contact with both the pin and the circumferential surface of the receptacle opening  24 . The coil  38  is movable along the pin  32  and remains in the receptacle opening  24 . 
     The electrical connection is provided by moving the pin  32  through the receptacle opening  24  and the hole  15  defined in the connection plate  12  as the two components are moved relative to each other. The coil  38  is also moved along the pin  32  while being maintained in the opening  24 , in electrical contact with both the pin  32  and the receptacle plate  18 . 
     In a particular embodiment, hermetic sealing is also provided between the pin  32  and the receptacle plate  18 . Hermetic sealing may be ensured by covering the space defined between the lateral surface of the pin  32  and the circumferential surface of the receptacle opening  24 . For example, the stop member  40  and rubber seal  46 , both having a central opening for receiving the pin  32  therein, may be biased against the receptacle plate  18  to retain the coil  38  within the receptacle opening  24  and to ensure hermetic sealing between the pin  32  and the receptacle plate  18 . 
     The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. Modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.