Abstract:
A junction box for a probe is disclosed for connecting to a sensor assembly of the probe, wherein the sensor assembly has a housing and a plate. The junction box comprises stopper walls, retaining flanges, and a retainer spring to secure the plate junction box. The probe can be assembled by inserting the sensor assembly through the opening, pressing the plate onto the at least one retainer spring and elastically deforming the at least one retainer spring, and rotating the sensor assembly into an assembled position.

Description:
BACKGROUND OF THE INVENTION 
     The subject matter disclosed herein relates to probes with junction boxes, and more particularly, to the attachment of a probe to a junction box. 
     Some probes, such as but not limited to CO 2  duct probe transmitters, can have a sensor assembly attached to a junction box. The sensor assembly can have a sensor housing enclosing or partially enclosing one or more sensors, and a sensor plate attached to one end of the sensor housing. The junction box can have an opening on one side to fit the sensor housing. The sensor housing can be inserted through the opening so that the sensor plate attached to one end of the sensor housing can mate against the inside surface of the side of the junction box with the opening, and the cylindrical sensor housing can protrude from the junction box. The inside surface of the junction box can have a mating area defined by walls that enclose an area to fit the shape of the sensor plate. 
     In some installations, a snap clip is aligned on each edge of the mating area on the inside surface of the junction box. Each snap clip has a base extending a short length along the end of the mating area and extending perpendicularly from the mating area of the junction box to a ramped portion overhanging the mating area and tapering toward the tip that is extended farthest from the mating area. In assembling the sensor assembly with the junction box, the sensor housing can be inserted through the opening through the mating area until the sensor plate contacts the ramped portion of the snap clips. The snap clips interfere with the further progression of the sensor plate, so an additional force is applied to press the sensor plate past the ramped portion until the sensor plate mates against the inside mating area of the junction box. The snap clips are intended to elastically deform or flex outward and then snap back to a non-flexed or non-deformed position after the sensor plate is pushed past the ramped, overhanging portion. When the ramped overhanging portion snaps back into the non-flexed or non-deformed position, the ramped overhanging portion is intended to retain the sensor plate against the mating area of the junction box. Each wall or snap clip base is intended to retain the sensor plate from sliding against the inside surface of the junction box in one direction. 
     The snap clip design can be prone to several deficiencies. During the first use, rather than elastically deforming when the sensor plate is pressed into place, the snap clip can be permanently deformed, compromising the strength, tightness, and proper fit with which the sensor plate is held to the junction box. The snap clip can also break. For example, the base wall can break or the tapered portion can sheer off or snap off. Permanent deformation and/or breaking become increasingly likely to occur with each repeated assembly or disassembly, which makes disassembly and reassembly after the initial assembly problematic. Disassembly is more complicated than assembly as the sensor plate cannot simply be pulled apart from the junction box. Snap clips must be pried back to allow the sensor plate to be pulled away freely, which increases the likelihood of breaking a snap clip either by improperly pulling away the sensor plate with one or more snap clips still obstructing, or by putting too much force on the snap clips when prying the snap clips back. When a snap clip breaks, the junction box must be replaced at additional cost. 
     Therefore, there is a need for a more durable and easier method and/or apparatus to assemble and disassemble a sensor assembly with a junction box. 
     The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. 
     BRIEF DESCRIPTION OF THE INVENTION 
     A junction box for a probe is disclosed for connecting to a sensor assembly of the probe, wherein the sensor assembly has a housing and a plate. The junction box comprises stopper walls, retaining flanges, and a retainer spring to secure the plate junction box. An advantage that may be realized in the practice of some disclosed embodiments of the junction box is easier and more durable assembly and/or disassembly. 
     In one exemplary embodiment, a junction box for a probe is disclosed for connecting to a sensor assembly of a probe, wherein the sensor assembly has a housing and a plate. The junction box can comprise a wall comprising an opening configured to accept insertion of the housing, a mating area on the interior surface of the wall, wherein the mating area comprises a perimeter encompassing the opening and is sized and shaped to be congruent with the plate, at least two stopper walls aligned proximate the perimeter of the mating area projected outward from the interior surface of the wall to obstruct the plate from rotating in a first rotational direction out of an assembled position, at least two retaining flanges, wherein each of the at least two retaining flanges projects from one of the stopper walls and extends over the mating area at a distance offset from the interior surface of the wall to obstruct the plate from moving out of the assembled position in a direction perpendicular to the interior surface of the wall, and at least one retainer spring comprising an interior edge aligned in a plane proximate the perimeter of the mating area and projecting outward from the interior surface of the wall, wherein the at least one retainer spring is elastically deformable and configured to be pressed toward the interior surface of the wall during assembly without permanently deforming and to return to a non-flexed position when the plate reaches the assembled position to obstruct rotation of the plate in a second rotational direction opposite the first rotational direction out of the assembled position. 
     In another exemplary embodiment, a junction box for connecting to a sensor assembly of a probe is provided. The sensor assembly can have a housing and a plate, and the junction box can comprise a wall, a mating area on the interior surface of the wall, at least two stopper walls, at least two retaining flanges, and at least one retainer spring. The wall can comprise an opening configured to accept insertion of the housing. The mating area can comprise a perimeter encompassing the opening and can be sized and shaped to be congruent with the plate. The at least two stopper walls can be aligned proximate the perimeter of the mating area and can project outward from the interior surface of the wall to obstruct the plate from rotating in a first rotational direction out of an assembled position. The at least two retaining flanges can project from one of the stopper walls and can extend over the mating area at a distance offset from the interior surface of the wall to obstruct the plate from moving out of the assembled position in a direction perpendicular to the interior surface of the wall. The at least one retainer spring can comprise an interior edge, a base portion, a stepped portion, and a pressing portion, wherein the interior edge is aligned in a plane proximate the perimeter of the mating area and projecting outward from the interior surface of the wall. The base portion can extend from the interior surface of the wall. The stepped portion can extend from the base portion and can project outward from the interior surface of the wall. The pressing portion can extend from the stepped portion substantially parallel to the interior surface of the wall. The at least one retainer spring can be elastically deformable and can be configured to be pressed toward the interior surface of the wall during assembly without permanently deforming and can be configured to return to a non-flexed position when the plate reaches the assembled position to obstruct rotation of the plate in a second rotational direction opposite the first rotational direction out of the assembled position. 
     In another exemplary embodiment, a method of assembling a junction box and a sensor assembly of a probe is disclosed. The sensor assembly can comprise a housing and a plate. The junction box can comprise a wall, a mating area with a perimeter on the interior of the wall, at least two stopper walls aligned proximate the perimeter of the mating area, at least two retaining flanges, and at least one retainer spring, wherein the wall comprises an opening, the perimeter of the mating area encompasses the opening, the at least two stopper walls project outward from the interior surface of the wall, each of the at least two retaining flanges project from one of the stopper walls and extends over the mating area at a distance offset from the interior surface of the wall, and at least one retainer spring comprises an interior edge aligned in a plane proximate the perimeter of the mating area and projects outward from the interior of the surface of the wall. The method can comprise the steps of providing the sensor assembly and the junction box, inserting the sensor assembly through an opening of the junction box, pressing the plate onto the at least one retainer spring and elastically deforming the at least one retainer spring, and rotating the sensor assembly into an assembled position. 
     This brief description of the invention is intended only to provide a brief overview of subject matter disclosed herein according to one or more illustrative embodiments, and does not serve as a guide to interpreting the claims or to define or limit the scope of the invention, which is defined only by the appended claims. This brief description is provided to introduce an illustrative selection of concepts in a simplified form that are further described below in the detailed description. This brief description is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the features of the invention can be understood, a detailed description of the invention may be had by reference to certain embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the drawings illustrate only certain embodiments of this invention and are therefore not to be considered limiting of its scope, for the scope of the invention encompasses other equally effective embodiments. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the features of certain embodiments of invention. In the drawings, like numerals are used to indicate like parts throughout the various views. Thus, for further understanding of the invention, reference can be made to the following detailed description, read in connection with the drawings in which: 
         FIG. 1  is a perspective view of an unassembled probe, with a sensor assembly and an open junction box, in an exemplary embodiment of the invention; 
         FIG. 2  is a top view of the probe of  FIG. 1 , illustrating the sensor assembly being assembled with the junction box, in one embodiment of the invention; and 
         FIG. 3  is a top view of the probe of  FIG. 1  illustrating the probe with the sensor assembly and the open junction box assembled, in one embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a perspective view of an unassembled probe  10 , with a sensor assembly  100  and open junction box  200 , in an exemplary embodiment of the invention. The sensor assembly  100  can comprise a sensor housing  110  and a sensor plate  120 . As shown in  FIG. 1 , the sensor housing  110  can be cylindrical, and the sensor plate  120  can be on one end of the sensor housing  110 . The sensor plate  120  can be rectangular, and the sensor plate  120  can be perpendicular to the sensor housing  110 . It will be understood that the sensor housing  110  and the sensor plate  120  can each be shaped otherwise, as would be known by one skilled in the art. 
     The junction box  200  is shown open with a lid  201  removed from the open side. The junction box  200  can comprise a wall  202  opposite the open side with an interior surface  203  defining an opening  204  through the wall  202 . The opening  204  can correspond to the shape and size of the sensor housing  110 . In the illustrated embodiment, because the sensor housing  110  is substantially cylindrical, the opening  204  is circular, and sized with a diameter large enough to pass through the substantially cylindrical sensor housing  110 . 
     The interior surface  203  of the junction box  200  that defines the opening  204  can comprise a mating area  206 . The mating area  206  can have a perimeter  207 , can encompass the opening  204 , can correspond to the shape and size of the sensor plate  120 , and can comprise rests  220 . In the illustrated embodiment, because the sensor plate  120  is substantially rectangular, the mating area  206  is substantially rectangular. The mating area  206  and the sensor plate  120  can have one or more congruently shaped asymmetrical features to promote proper orientation of the sensor plate  120  with respect to the junction box  200  during assembly. For example, one corner can be chamfered on the mating area  206  and the sensor plate  120 , to indicate the proper orientation of the sensor plate  120  with respect to the mating area  206 . In another example, the opening  204  can be offset from the center of the mating area  206 , and the sensor housing  110  can similarly be offset from the center of the sensor plate  120 , to promote proper orientation. In another example, the mating area  206  and the sensor plate  120  can be similarly long or short in one dimension, so that the sensor plate  120  only fits to the mating area  206  in the desired orientation. 
     Adjacent to the mating area  206 , the junction box  200  can comprise at least one retainer spring  208 . Each retainer spring  208  can have an interior edge in a plane proximate or aligned along the perimeter  207  of the mating area  206 . Each retainer spring  208  can project outward from the interior surface  203 . Each retainer spring  208  can have a base portion  210 , a stepped portion  212 , and a pressing portion  214 . The base portion  210  can extend substantially parallel to the interior surface  203  of the junction box  200  either aligned substantially with the plane of the interior surface  203  of the junction box  200  or offset in either direction from the plane of the interior surface  203  of the junction box  200 . Alternatively, the base portion  210  can be angled outward from the interior surface  203 . 
     The stepped portion  212  can extend from the base portion  210  and project outward from the interior surface  203  of the junction box  200 . The projection can range between perpendicular to the interior surface  203  of the junction box  200  and parallel to the interior surface  203  of the junction box  200 . A first bend  211  can delineate between the base portion  210  and the stepped portion  212 . A second bend  213  can delineate between the stepped portion  212  and the pressing portion  214 . Each bend  211 ,  213  can be abrupt (e.g., having a relatively small radius) or gradual (e.g., having a relatively large radius). The pressing portion  214  can extend from the stepped portion  212  substantially parallel to the interior surface  203  of the junction box  200 , as illustrated in  FIG. 1 , or can also be angled at an offset from parallel. 
     In the embodiment illustrated by  FIG. 1 , there are two retainer springs  208  on opposing sides of the mating area  206  180 degrees from each other. Other configurations and numbers of retainer springs  208  are conceived. For instance, there can be more or less retainer springs  208  (e.g., one, three, or four), or the retainer springs  208  can be positioned in different locations along the respective edge of the mating area  206 . More retainer springs  208  could more securely lock the sensor plate  120  to the mating area  206 . Less retainer springs  208  could decrease manufacturing costs and make it easier to disassemble the sensor assembly  100  from the junction box  200 . Having two retainer springs  208  on opposing sides of the mating area  206  can provide a balanced force to retain the sensor plate  120  when the sensor assembly  100  is assembled with the junction box  200 . 
     Also adjacent to the mating area  206 , the junction box  200  can comprise at least two stopper walls  216 . Each stopper wall  216  can comprise an edge aligned on or proximate the perimeter  207  of the mating area  206 . Each stopper wall  216  can be attached to the interior surface  203  of the junction box  200  and can project outward (e.g., substantially perpendicularly) from the interior surface  203 . Each stopper wall  216  can extend a relatively short length along the respective edge of the mating area  206  with respect to the full length of the respective edge. Each stopper wall  216  can have a chamfered or tapered end  217 . 
     Two or more stopper walls  216  can further comprise a retaining flange  218  that projects from the stopper walls  216  at a distance offset from the interior surface  203 , and that extends over the mating area  206  substantially parallel to the interior surface  203 . The offset distance can be large enough at least to fit the thickness of the sensor plate  120  between the retaining flange  218  and the mating area  206 , including any rests  220  that are part of the mating area  206  and that project outward from the interior surface  203 . Each retaining flange  218  can be positioned on an end of the length of one of the stopper walls  216  nearest a corner between two edges of the mating area  206 . 
     As illustrated in  FIG. 2 , to assemble the sensor assembly  100  with the junction box  200 , the sensor assembly  100  can be inserted through the opening  204  until the sensor plate  120  contacts the retainer springs  208 . When the sensor plate  120  contacts the retainer springs  208 , the sensor assembly  100  can continue to be inserted so that the sensor plate  120  depresses the elastically deformable retainer springs  208  until the sensor plate  120  presses against the mating area  206 , including any rests  220 . The mating area  206  can be a smooth and/or flat surface upon which the sensor plate  120  presses flush. Alternatively, the mating area  206  can be comprised of the rests  220  that can protrude from the smooth and/or flat surface of the mating area  206 , and the sensor plate  120  can seat against the rests  220 . The rests  220  can be located around the perimeter  207  of the mating area  206  or be positioned elsewhere within the mating area  206 . Some of the rests  220  can be positioned to enclose an elastically deformable seal or gasket  300  that can seal the joint between the sensor plate  120  and the mating area  206  around the opening  204 , when the sensor assembly  100  is assembled with the junction box  200 . 
     In one embodiment, the gasket  300  can be positioned between the sensor plate  120  and the mating area  206 , and when the sensor assembly  100  is inserted through the opening  204  until the sensor plate  120  contacts and depresses the retainer springs  208 , the sensor plate  120  also contacts and compresses the gasket  300  between the mating area  206  and the sensor plate  120 . The gasket  300  can provide a force pushing the sensor plate  120  outward from the mating area  206  and the interior surface  203  of the wall  202 . 
     In order to insert the sensor housing  110  fully through the opening  204  to contact the sensor plate  120  against the retainer springs  208 , the sensor plate  120  can be oriented rotationally to a position in which the sensor plate  120  will avoid contacting the stopper walls  216  and/or the retaining flange  218  during insertion. This position of the sensor plate  120  during insertion can be at a rotational orientation offset from the mating area  206  so that the shape of the sensor plate  120  does not align with the shape of the mating area  206 . The closer the stopper walls  216  and/or the retaining flanges  218  are positioned to the corners of the perimeter  207 , the more space there can be for the sensor plate  120  to be inserted to contact the retainer springs  208  without being obstructed by the retaining flanges  218  or the stopper walls  216 . 
       FIG. 3  is a top view of the probe  10  of  FIG. 1  illustrating the probe  10  with the sensor assembly  100  and the open junction box  200  assembled, in one embodiment of the invention. As illustrated in  FIG. 3 , once the sensor assembly  110  is fully inserted through the opening  204  so the sensor plate  120  depresses the elastically deformable retainer springs  208  and the sensor plate  120  presses against the gasket  300  and/or the mating area  206 , including any rests  220 , the sensor assembly  100  can be rotated into an assembled, position locked under the retaining flanges  218  by rotating the sensor plate  120  in one direction until the sensor plate  120  corresponds and fits with the mating area  206 . In the assembled, locked position, the sensor plate  120  is obstructed from rotating in one direction out of the assembled position by the stopper walls  216 . 
     As shown in  FIG. 3 , the sensor plate  120  can be rotated counter-clockwise to move the sensor plate  120  into the locked position. If rotated clockwise, the sensor plate  120  will be obstructed by the chamfered or tapered end  217  of the stopper walls  216 . The taper or chamfer can be angled to provide a flat surface to stop the sensor plate  120  from rotating in the incorrect direction, so that a sharp corner does not scratch or otherwise damage the sensor plate  120 . In other configurations, the sensor plate  120  can be rotated clockwise to move the sensor plate  120  into the locked position, rather than counter-clockwise. 
     When the sensor plate  120  is rotated into the assembled position, the sensor plate  120  slides between the mating area  206  and the retaining flanges  218 , and abuts the stopper walls  216 . The retaining flanges  218  can obstruct or retain the sensor plate  120  from moving out of the assembled position in a direction perpendicular to the interior surface  203  of the junction box  200 . There can be an interference fit between the sensor plate  120  and the retaining flanges  218 . A relatively large amount of interference can produce a relatively tight lock, while requiring a relatively large force to rotate the sensor plate  120  into or out of the assembled position. A relatively small amount of interference can produce a relatively loose lock, while requiring a relatively small force to rotate the sensor plate  120  into or out of the assembled position. If a tighter fit is necessary, then using a retaining flange  218  that has some degree of elasticity or flexibility can help reduce the amount of force necessary to rotate the sensor plate  120  into or out of the assembled position, and can also help reduce the possibility the retaining flange  218  might break under the force from the sensor plate  120 . Alternatively, the fit can be tight without any interference, so that the sensor plate  120  fits securely within a specified and desirable tolerance. In one embodiment using the gasket  300  between the sensor plate  120  and the mating area  206  around the opening  204 , the gasket  300  can be thick enough to add pressure to force the sensor plate  120  against the retaining flanges  218 . The gasket  300  can facilitate a tight fit and alleviate any clearance or looseness. The stopper walls  216  can prevent the sensor plate  120  from rotating out of the assembled position in one direction of rotation, or from over-rotating when positioning the sensor assembly  100  into the assembled position. 
     During rotation of the sensor plate  120  into the assembled position, pressure can be maintained on the retainer springs  208  to push the sensor plate  120  far enough toward the mating area  206  to have clearance (or a low enough friction if there is an interference fit with the retaining flanges  218 ) to rotate the sensor plate  120  under the retaining flanges  218 . When the sensor plate  120  is rotated into the assembled position, the sensor plate  120  moves off the retainer springs  208 , leaving the retainer springs  208  free and unobstructed to snap back to a non-flexed position. In the non-flexed position, the retainer springs  208  project away from the interior surface  203  of the junction box  200  so that the retainer springs  208  further lock the sensor plate  120  into place, preventing rotation of the sensor plate  120  in the opposite direction that the stopper walls  216  prevent rotation of the sensor plate  120 . 
     In the illustrated embodiment, there are four stopper walls  216 , four retaining flanges  218 , and two retainer springs  208 . Each stopper wall  216  stops one edge of the sensor plate  120 , near a corner of the sensor plate  120  and/or a corner of the mating area  206 , while allowing enough room for the sensor plate  120  to fit against the mating area  206  to be rotated into the assembled position. Having a relatively large number of stopper walls  216  and retaining flanges  218  provides relatively greater durability and strength, as the overall force applied to the stopper walls  216  and the retaining flanges  218  is distributed over more stopper walls  216  and retaining flanges  218 . The illustrated embodiment shows two retainer springs  208 , each on an opposing side of the mating area  206 . A relatively larger number of retainer springs  208  will distribute the locking force over more retainer springs  208  and reduce the force on each individual retainer spring  208 . Other configurations are conceived with varying shapes for the mating area  206  and varying numbers and positions of the stopper walls  216 , the retaining flanges  218 , and the retainer springs  208  that are well within the scope of this application based on the reasons and description set forth herein. 
     To disassemble the sensor assembly  100  from the junction box  200 , the reverse steps can be followed. The retainer springs  208  can be depressed, freeing the sensor plate  120  to be rotated out of the assembled position, and the sensor housing  110  can be withdrawn through the opening  204 . This quick and efficient operation produces minimal strain on the parts, which reduces the occurrence of a part breaking, increases the ease of assembling and disassembling the probe  10 , and increases the ability to assemble, disassemble, and reassemble the probe  10  multiple times. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.