Abstract:
A container to secure an x-ray source is provided. The container includes a base and a cover each having an inside surface. The base and cover are assembled together forming a fluid tight chamber defined by the inside surfaces of the base and cover to secure x-ray source components to positions along the inside surface of the base. A plurality of these positions are machinable to provide a precision arrangement of at least a portion of the x-ray source components and at least one fluid tight seal between x-ray source components and the base. During fabrication of the base, each position of the inside surface required to provide a precise arrangement of at least a portion of the x-ray source components and at least one fluid tight seal between the x-ray source components and the base being accessible from exterior of the base by a substantially straight tool.

Description:
FIELD OF THE INVENTION 
   The present invention is directed to a container for use with x-ray equipment, and more particularly, is directed to a container that is used in dental x-ray equipment to house an x-ray source. 
   BACKGROUND OF THE INVENTION 
   X-ray equipment is commonly used in the dental industry to assist dental professionals. Typically, the x-ray source and associated components are enclosed within a suitable high voltage housing, referred to as a tubehead housing, which contains a high-dielectric insulating fluid, such as dielectric oil, that also operates as a coolant. The housing may also provide shielding of the unwanted radiation outside a designated output window formed in the housing. It is important that the assembled tubehead housing provides a fluid tight seal to prevent inadvertant leakage of the dielectric oil from the tubehead housing. 
   Typically, the tubehead housing resembles a rectangle, i.e., having adjacent surfaces disposed at right angles to each other. For ease of assembly and to minimize the opportunity for leakage, it is preferred that the tubehead housing is comprised of only two pieces, such as a box structure and a lid. However, to complicate matters, portions of the tubehead housing surface require precision machining for such reasons as alignment between certain components within the tubehead housing and providing a fluid tight seal between tubehead housing components and the tubehead housing. Currently, tubehead housing configurations require precision machining to be performed on each portion of the tubehead housing, which significantly increases manufacturing costs. Additionally, such precision is further complicated in that the precision machining for at least one portion of the tubehead housing cannot be performed by a standard machining tool, such as an end mill, which requires “straight on” access. In other words, a straight cutting tool that can only be advanced in a straight line is incapable of machining all the required surfaces of at least one of the tubehead housing portions. The additional nonstandard precision machining techniques required to machine these remaining surfaces further increase manufacturing costs. Finally, once machining to the tubehead housing has been completed and the internal components installed, current tubehead housing configurations fail to provide sufficient accessibility to the internal components. 
   What is needed is a tubehead housing construction for securing x-ray components therein that is easy to manufacture, including subsequent precision machining, and having ease of accessibility to internal components when the tubehead housing is disassembled. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a container to secure an x-ray source including a base having an inside surface and a cover having an inside surface and being detachably connected to the base. The base and the cover are configured and disposed to form a fluid tight chamber defined by the inside surfaces of the base and cover, the inside surface of the base comprising a plurality of attachment positions for x-ray source components, the plurality of attachment positions being precision machined into the inside surface of the base. During fabrication of the base, each attachment position of the plurality of attachment positions being accessible from exterior of the base by a substantially straight tool. 
   The present invention also relates to a method of manufacturing a container for an x-ray source including: forming a base having an inside surface; forming a cover having an inside surface and being detachably connectable to the base, the base and the cover being configured and disposed to form a fluid tight chamber defined by the inside surface of the base and cover; and precision machining a plurality of attachment positions for x-ray source components into the inside surface of the base by a substantially straight tool. 
   The present invention further relates to a container to secure an x-ray source including a base having an opening, an inside surface and an outside surface, the outside surface including a substantially planar portion opposite the opening. A cover has an opening, an inside surface and an outside surface opposite the opening, the outside surface including a substantially planar portion, the cover being detachably connectable to the base. The base and the cover are configured and disposed to form a fluid tight chamber defined by the inside surfaces of the base and cover to secure x-ray source components therein. A junction along the openings of the base and cover is nonparallel to the substantially planar portions of the outer surfaces of the base and cover. 
   An advantage of the present invention is that it can be constructed from a casting. 
   A further advantage of the present invention is that only the base of the tubehead housing requires precise machining. 
   A still further advantage of the present invention is that machining of the base of the tubehead housing can be achieved by a substantially straight tool directed from exterior of the tubehead housing. 
   An additional advantage of the present invention is that when the tubehead housing is assembled or disassembled, x-ray components are readily accessible. 
   Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded perspective view x-ray components that are secured inside of a tubehead housing of the present invention. 
       FIGS. 2–4  show different views of a cove of a tubehead housing of the present invention. 
       FIGS. 5–7  show different views of a base of a tubehead housing of the present invention. 
   

   Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
   DETAILED DESCRIPTION OF THE INVENTION 
   One embodiment of a tubehead housing  10  of the present invention is depicted in  FIG. 1  Preferably, the tubehead housing  10  includes a base  12  and a cove  14  that secure x-ray system components  16  therebetween. For purposes of orientation, a substantially planar surface  55  of the cover  14  is referred to herein as rear surface  55 , and an opposed substantially planar surface of the base  12  is referred to herein as a front surface  86 . The x-ray components  16 , include an x-ray tube  18  that is secured with a tube holder  20 , a radiation filter  42 , a high voltage multiplier  24 , and a transformer  26 . Electrical power provided by an electrical power source is supplied to the x-ray components  16  via a pair of electrical connectors  46 . Both the x-ray components  16  and the electrical connectors  46  are secured to the base  12 , although the high voltage multiplier  24  is more accurately sandwiched between extensions  78 ,  56  (see  FIGS. 4 and 5 ) formed in the respective base  12  and cover  14 . Once the x-ray components  16  are secured to the base  12 , a peripheral flange  38  of the base  12  and a peripheral flange  36  of the cover  14  are brought together with a gasket  40  interposed between the flanges  36 ,  38 . Fasteners  34  sufficiently compress the gasket  40  between the flanges  36 ,  38  to achieve a fluid tight seal therebetween. A dielectric fluid (not shown) is then pumped inside the tubehead housing  10 , with a bellows  28  that is secured to a port  30  by a clamp  32 . The bellows  28  compensates for volume changes inside the tubehead housing  10 , primarily due to temperature changes and differing coefficients of volumetric expansion/contraction between the dielectric fluid, tubehead housing  10  and x-ray components  16 . 
   As will be discussed in further detailed below, the construction of the tubehead housing  10 , notably the angled portion defined by the flanges  36 ,  38  of the respective cover  14  and base  12 , permits a significant reduction in costs associated with the manufacturing of the tubehead housing  10 , as well as improved accessibility of the installed x-ray system components  16 . 
   Referring to  FIGS. 1–4 , the cove  14  preferably includes a narrow end  48  extending to a wide end  50 , cover  14  substantially defining a wedge shape. The cover  14  has an outside surface  54  and an inside surface  52  with a pair of extensions  56  extending away from the inside surface  52  to help secure the high voltage multiplier  24  ( FIG. 1 ). Surrounding the inside surface  52  and separating the inside surface  52  from the outside surface  54  is peripheral flange  36  that contacts the peripheral flange  38  of the base  12  when assembled. The gasket  40  located between flanges  36 ,  38  is positioned such that a compressing gasket  40  between flanges  36 ,  38  achieves a fluid tight seal. Preferably, flange  36  is substantially planar, as shown in  FIG. 3 , and defines an acute angle  60  with the rear surface  55  of the cover  14 . Specifically, the narrow end  48  has a first height in extending between the flange  36  and rear surface  55  and the wide end  50  has a second height greater than the first height in extending between the flange  36  and rear surface  55 . In a preferred embodiment, the cover  14  is constructed of metal, and more preferably cast metal, although other suitable materials can be used. Preferably, angle  60  is sized so that flange  36  is neither perpendicular nor parallel to either of the inside or outside surfaces  55 ,  55  or the surface adjacent the wide end  50 . 
   Additionally, a preferred embodiment of the cover  14  does not require subsequent precision machining operations after forming. The term “subsequent precision machining operations” is not intended to include normal cleanup operations, such s removing casting edge irregularities formed at the junction of parting dies, which may be quickly performed by passing a grinding wheel along a rough edge of the cover  14 . However, subsequent precision machining is intended to refer to machining operations considered critical to component alignment or fit, requiring a sufficiently high degree of precision that the amount of material removed must be closely monitored, and cannot typically be performed manually without tooling. In the above example, it certainly is not crucial to remove edge casting irregularities extending radially outwardly along the outer periphery of the flange  36  (along the die partition line) other than what is required to break sharp edges. 
   Referring to FIGS.  1  and  5 – 7 , base  12  preferably includes a narrow end  70  extending to a wide end  72 , base  12  substantially defining a wedge shape. The base  12  has an outside surface  84  and an inside surface  22  with a pair of extensions  78  extending away from the inside surface  22  to help secure the high voltage regulator  24  ( FIG. 1 ). Surrounding the inside surface  22  and separating the inside surface  22  from the outside surface  84  is peripheral flange  38 , which contacts the peripheral flange  36  of the cover  14 . The gasket  40  located between flanges  36 ,  38  is positioned and partially embedded in a peripheral groove  74  formed in flange  38  such that compressing gasket  40  between flanges  36 ,  38  achieves a fluid tight seal. The inside surfaces  22 ,  52  of the assembled cover  14  and base  12 , respectively, form a chamber configured to contain the x-ray components  16  therein. Preferably, other than the groove  74 , flange  38  is substantially planar, as shown in  FIG. 6 , and defines an acute angle  82  with the front surface  86  of the cover  14 . In a preferred embodiment, the base  12  is constructed of metal, and more preferably cast metal, although other suitable materials can be used. Preferably, angle  82  is sized so that the flange  38  is neither parallel nor perpendicular to either of the front surface  86  or the surface adjacent wide end  72 . 
   Contrary to the cover  14 , which does not require subsequent precision machining, the base  12  includes several positions along the inside surface  22  and the outside surface  84  that require subsequent precision machining. For example, one position typically requiring such machining is a recess  44  disposed opposite front surface  86  to ensure the radiation filter  42  forms a fluid tight seal with the inside surface  22 . Adjacent to the recess  44 , another position is an aperture pattern  45  which secures the x-ray tube holder  20 , since alignment between the x-ray tube holder  20  and the base  12  is critical. In other words, not only is the location of the apertures of the aperture pattern  45  with respect to each other and with respect to the base  12  of critical importance, but also, the planar alignment of the apertures of the aperture pattern  45  with respect to locating points along the outside surface  84 . Additionally, other positions along the inside surface  22  include the aperture patterns  80  disposed along the wide end  72 . Although the locations of the aperture patterns  80  with respect to each other or with respect to the base  12  may not be critical, each of the aperture patterns  80  require precision machining along the inside surface  22  to ensure a fluid tight seal between the electrical connectors  46  and their corresponding aperture pattern  80 . 
   To minimize the dimensions of the tubehead housing  10  in one embodiment, the electrical connectors  46 , and therefore the corresponding aperture patterns  80 , are disposed in the base  12  along the wide end  72 . In this arrangement, the aperture patterns  80  are not only separated from the recess  44  and adjacent aperture pattern  45 , but are formed in different orientations, as the wide end  72  and the front surface  86  are substantially perpendicular. Such an arrangement in prior art tubehead housing constructions would present machining access problems in that a straight tool  88  ( FIG. 6 ) could not access all the different positions requiring precision machining. However, due to the novel angled flange  38  construction, it is appreciated that the portion of the flange  38  adjacent to the narrow end  70  is disposed so that a straight tool  88  can directly access aperture patterns  80  from exterior of the base  12 . Similarly, the straight tool  88  can directly access the recess  44  and the aperture pattern  45  from exterior of the base  12 . This ability to directly access all of the inside surface positions from exterior of the base  12  by the straight tool  88  significantly reduces manufacturing costs. 
   By virtue of the angle  82  between the flange  38  and the front surface  86  of the base  12  being substantially equal to the angle  60  between the flange  36  and the rear surface  55  of the cover  14 , forming alternate interior angles when the base  12  is assembled to the cover  14 , the front surface  86  and the rear surface  55  are substantially parallel. While preferred, it is not necessary that the angles  60 ,  82  be substantially equal, or that the front surface  86  and the rear surface  55  be substantially parallel. It is to be understood that the angles  60 ,  82  can range significantly in magnitude to accommodate the components inserted between the assembled base  12  and cover  14 . However, in a preferred embodiment the angles  60 ,  82  range from about 12 to about 40 degrees. 
   It is also appreciated by those skilled in the art that having the angled flange  38  in the base  12  improves accessibility of x-ray components  16  secured to the inside surface  22 . Although it is preferred that the flanges  36 ,  38  of respective cover  14  and base  12  are planar, it is not required, so long as the profiles correspond to each other and define an overall profile that is not parallel to the respective front or rear surfaces. Further it is to be understood that the acute angles  60 ,  82  can be compound angles. That is, neither wide ends  72 ,  50  nor narrow ends  70 ,  48  of respective base  12  and cover  14  are required to be of uniform width. 
   While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.