Patent Publication Number: US-6702895-B1

Title: Ribbed electroplating barrel

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to electroplating barrels, and in particular to a design for a barrel having side panels and an access door with an improved locking mechanism utilizing a unique combination of support ribs and elongated perforations which encourage efficient circulation of the electroplating solution. 
     The use of polygonal shaped barrels, and particularly hexagonal shaped barrels is well known in the prior art. These barrels generally include an access point on one side of the barrel for putting the material to be electroplated into the barrel and then removing it after the process has been completed. This process is usually accomplished by dipping the barrel into a bath of electroplating solution and then running an electric current through the barrel while rotating the barrel on an axis. 
     The passage of the solution into the barrel has generally been accomplished by either the use of a chemically inert mesh fabric as seen in U.S. Pat. No. 3,472,753, or through the use of small circular or square perforations in a solid chemically inert panel as seen in U.S. Pat. Nos. 3,936,985 and 5,639,306. 
     However, these barrels have been generally used in an industrial setting where rough handling is commonplace and the barrels must repeatedly sustain such treatment. As a consequence the mesh design was unable to effectively deal with these repeated stresses. This problem has been addressed by utilizing a combination of rib segments where at each intersection one such segments ends with the small circular perforation discussed above as seen in U.S. Pat. No. 5,639,306. 
     However, in that device, along with all other prior art, the problem of maintaining efficient circulation of electroplating solution while minimizing the capillary effect, also known as “drag-out”, produced through the utilization of circular openings has played a secondary role to the maintenance of the structural stability of the barrel. Considering that problem, it is an object of the present invention that the “drag-out” of solution is minimized while the barrel still possesses a rib structure and door locking mechanism that can withstand the rigors of a manufacturing environment. 
     It is another object of the invention to utilize a support rib structure and door locking mechanism that will withstand the rigors of manufacturing while increasing the circulation of electroplating solution in the electroplating tank, thus increasing efficiency of the electroplating process. 
     It is a further object of the invention to design a side panel which will allow for easy replacement and introduction into the manufacturing environment. 
     SUMMARY OF THE INVENTION 
     This invention comprises a rotatable barrel for holding objects to be electroplated having at least one perforated side panel that permits the efficient transfer of electroplating solution into and out of the barrel with minimal “drag out” effect. The design of the side panel includes a base along with a support rib structure that defines sections of the panel that are the shape of a parallelogram. Within the parallelogram shaped section are elongated and cross segments that define elongated perforations, which allow the solution to enter and exit the barrel while retaining the electroplated pieces inside. The barrel preferably is constructed of a chemically inert material. The interior of the barrel, that is the side of the panel opposite the ribs can, be either smooth or uneven. 
     The support ribs run generally in the direction of the length and the width of the panel but with the ribs laid out so that the intersection points of the ribs always form complementary obtuse and acute angles with each other. The side of the panel opposite the ribs can be either smooth or uneven. In one embodiment the lengthwise ribs, also called longitudinal ribs, run parallel with the length edge of the panel, while the width ribs, also called cross ribs, run approximately 20° from parallel with the width edge of the panel. In another embodiment this arrangement could be switched so that the cross ribs run parallel with the width edge and the longitudinal ribs are angled to create the parallelogram shape. Increasing or decreasing the angle of the cross ribs could also modify the arrangement. 
     Circulation of the electroplating solution within the bath and the barrel has previously been directed by the rotation of the barrel in the bath. This rotation encouraged circulation only in primarily one direction. The angled arrangement of the ribs in this invention increases this circulation by directing the flow of the solution into and out of the barrel at an angle corresponding to the angle of the cross ribs. This creates a multi-directional circulation pattern within the tank and the barrel that corresponds to an increase in efficiency of electroplating. This efficiency is further enhanced by the utilization of access doors with an improved locking mechanism that enables the access doors to share an identical type of support rib structure. 
     This increase in circulation is also affected by the arrangement of the perforations within the parallelogram shaped sections. Prior barrels designs have generally utilized small square or circular holes through which the electroplating solution can pass into and out of the barrel, which, even when utilizing thin perforated plates, can lead to a large “drag out” of solution when the barrel is removed from the bath. The current invention reduces this “drag out” by increasing the size of the perforations so that less solution will remain. As the size of the perforations increases the likelihood of solution remaining trapped within the perforations decreases since it is more likely that the surface tension of the solution holding the solution to the opening will be overcome by gravity in the larger area. 
     In the past these perforations have always been small and usually circular due to concerns of the strength of the panel wall. This invention utilizes support segments arranged generally parallel to each other that define a pattern of rows of elongated openings. The elongated openings serve two purposes: 1) they decrease the “drag out” effect through their larger volume and 2) they increase the circulation of electroplating solution within the barrel by having the elongated perforations run parallel with one of the two directions of ribs. In another embodiment the support segments are interconnected by cross segments that serve to further strengthen the parallelogram shaped section. 
     It is the combination of these elements, the parallelogram shaped sections defined by support ribs and the parallel running elongated perforations within the parallelogram sections, that enable this invention to be the most efficient. However, either on their own are enough to increase efficiency of the electroplating process. 
     Furthermore, the barrel in this invention utilizes an improved door locking mechanism utilizing a crossbar with locking spherical rollers that enable the crossbar to be moved and secured into locked and unlocked positions. This removable door also utilizes the abovedescribed parallelogram shaped sections with elongated openings to increase electroplating solution circulation within the barrel. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the barrel with one access door removed. 
     FIG. 2 is an overhead view of the barrel. 
     FIG. 3 is an enlarged view of section I of FIG.  2 . 
     FIG. 4 is an enlarged perspective view of a side panel of the barrel. 
     FIG. 5 is a perspective view of an access door removed from the barrel. 
     FIG. 6 in an enlarged view of the center top portion of an access door and a crossbar with the spring mounted post removed. 
     FIG. 7 is the underside of a crossbar showing the annular indentations thereon. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In describing the preferred embodiments of the invention, reference will be made herein to FIGS. 1-7 of the drawings in which like numerals refer to like features of the invention. 
     Referring to the drawings, electroplating barrel  8  is constructed in accordance with the present invention as shown in FIG.  1 . The specific design of barrel  8  includes a plurality of perforated side panels  20  longitudinally spanning the distance between the end plates  10 ,  12  with each perforated side panel  20  of the barrel  8  employing a configuration of longitudinal ribs  23  and cross ribs  24  that support each perforated section and define the shape as that of a parallelogram and at least one door panel  30 . All of theses pieces being preferably constructed of a chemically inert durable polymer that is impact-resistant. 
     The preferred embodiment of the present invention is shown in FIG.  1 . The electroplating barrel  8  includes a plurality of perforated side panels  20  and at least one door panel  30 . Side panel  20  has longitudinal sides  21  and width sides  22  as shown in FIG.  4 . Such panels may be separately mounted whereby they are fixedly associated to collectively form a polygonal barrel with at least one door panel. Such panels my also form a solid one-piece plurality of panels, either configuration being known in the prior art. The door panel  30  further comprises door ribs  31  which define rectangular door openings  32 , into which fit access doors  41 ,  42  as shown in FIG.  1 . 
     The longitudinal side  21  of the side panel  20  may be secured to the longitudinal side  21  of another panel  20  or the door panel  30  by means of adhesive or any other means known in the art. The end sides may be secured to the end plates  10 ,  12  by similar means. End plates  10 , 12  have a circular center opening  14  for mounting onto a suspension and drive mechanism for use in the plating tank (not shown). Further, end plate  12  is attached to a geared plate  16 , which engages with an intermediate gear to facilitate the rotation of the barrel during the electroplating operation (not shown). 
     Removable access doors  41 ,  42 , preferably made of a chemically inert durable polymer, have dimensions that fit into the rectangular door openings  32 , 33  as shown in FIG.  1 . The length  43  and width  44  edges of the access doors  41 , 42 , as shown in FIG. 5, are angled such that they complimentary mate with the interior edges  34 ,  35  of the rectangular door openings  32 ,  33 , as shown in FIG.  1 . Access doors  41 ,  42  each further comprise a locking crossbar  45 , which is rotatably attached to the center of the access door by means of a spring-mounted post  46 , with the length  50 , as seen in FIG. 7, of the crossbar  45 , being longer than the width edge  44  of the access doors  41 ,  42  and the width  51  of the crossbar  45  being shorter than the width  34  of the door panel  30 . The side of the removable door  41 , 42  facing outward further has three annular indentations  47  formed thereon, being spaced equally from the spring-mounted post  46  and from each other, and of a complimentary diameter to receive spherical rollers  48 . The underside of the crossbar  45 , as seen in FIG. 7, has six annular indentations  49  spaced equally from the spring-mounted post  46  and from each other and have diameter complimentary to the spherical rollers  48 . The remaining surface of the access doors  41 , 42  have an identical structure parallelogram shaped opening as the side panels which are described below. 
     By rotating the locking crossbar  45  into a position so that the length  50  of the crossbar is substantially parallel with the end plates  10 ,  12 , as seen in FIG. 2, locking crossbar  45   a , in combination with the mated edges  43 , 44  and  34 , 35 , as seen in FIGS. 1 and 5 respectively, the access door is in the locked position and cannot be pushed down into the interior of the barrel  8 . In this locked position the spherical rollers  48  are secured in their access door indentations  47  and three of the cross bar indentations  49 . Then, by the operator (not shown) turning the locking crossbar  45  into a position where the locking member does not cross edge  43 , as seen in FIG.,  2  locking crossbar  45   b , the access door  41 ,  42  are in the unlocked position and can be removed by moving the access door  41 ,  42  into the interior of the barrel  8 , rotating the access door  41 ,  42  and lifting the access door  41 ,  42  through the rectangular door opening  32 ,  33 . During that turning of the crossbar  45 , the crossbar is lifted from the spherical rollers  48  by compressing the spring  52  of the spring mounted post  46  and the cross bar is rotated until the spherical rollers  48  are in alignment with the next annular indentations  49  of the crossbar and released whereby the spring  52 , pushes crossbar  45  down and into the unlocked position. The spherical rollers  48  due to their rounded nature enable the operator to easily, compared to prior locking mechanisms, rotate the crossbar  52 , yet still having a secure lock through the use of the multiple rollers. 
     Side panel  20 , as shown in FIG. 4, with longitudinal sides  21  and width sides  22  further comprises longitudinal ribs  23  and cross ribs  24  defining a plurality of parallelogram shaped sections  26 . The longitudinal ribs  23  extend outwardly from the side panel  20 , are parallel with each other, run from width side  22  to opposite width side  22  of the panel  20  and are parallel with the longitudinal sides  21 . The cross ribs  24  extend outwardly from the panel  20 , are parallel with each other, run from longitudinal side  21  to opposite longitudinal side  21  and are angled to intersect the longitudinal ribs  23  such that complementary acute and obtuse angles are formed at the intersection point  25 . The combination of four intersection points,  25   a ,  25   b ,  25   c  and  25   d  then define the corners of a section  26  in the shape of a parallelogram. This rib arrangement is identical on the access doors. 
     This parallelogram shape serves to increase the circulation of the electroplating bath with the barrel when submerged in the electroplating tank. This circulation is then further increased by the arrangement of the elongated openings  27  within the parallelogram shaped section  26 . This combination of longitudinal ribs  23  and cross ribs  24  enable the parallelogram shaped sections  26  defined by the rib structure to be very narrow. 
     The parallelogram shaped section  26 , as shown in detail in FIG. 3 from the access doors  41 , 42  and are identical on the side panel  20 , further comprises a plurality of support segments  28  that define elongated openings  27  which allow the electroplating solution to pass into the barrel  8  while keeping any parts (not shown) being electroplated from falling out. These openings differ from openings known in the prior art by the fact that they are elongated without compromising strength and thus result in a greater open area both per each elongated opening  27  and per each section  26 . This greater open area combined with the thin base allowed by the supporting rib structure allows the present barrel openings  27  to have a minimal capillary effect while still being strong enough to withstand the rigors of a manufacturing environment. The strength comes in part from the support segments  28  that define the elongated openings as differing sizes within the parallelogram shaped section aligned in rows of holes of uniform size as seen in FIG.  3 . 
     In the preferred embodiment this arrangement of support segments defines the openings as running parallel with the angled cross ribs  24  as seen in FIG.  3 . The support segments  28  comprise elongated segments  28   a  and cross segments  28   b . The elongated segments  28   a  run parallel with the cross ribs  24 . The cross segments  28   b  then interconnect the elongated segments  28   a  so that at each segment intersection point  29 , the cross segment  28   b  ends and does not continue past the elongated segment  28   a . These intersections define the boundaries of the elongated openings  27  through which the electroplating solution passes with minimal amounts of “drag-out” when the barrel is removed from the electroplating bath. These openings can either be of consistent length or varied length, with the preferred embodiment utilizing openings of varied length. The utilization of such larger openings than are known in the prior art allows the electroplating solution to pass quickly and efficiently into the barrel and a minimal capillary effect when the barrel is removed from the bath. In another embodiment this arrangement can also be formed by utilizing support segments  28  that define openings that run parallel to the longitudinal ribs  23 . 
     The above has been offered for illustrative purposes only and is not intended to limit