Abstract:
A metal finishing barrel side opening has a cover secured by a series of cover and barrel tabs, the cover slid into a secured position with the cover tabs partially overlain by the barrel tabs. A locking handle assembly includes a graspable portion supported on a deflectable spring blade attached to the cover at one end which allows the handle assembly to move away from an aligned locator feature on the barrel as the cover is pushed into position. When the cover is shifted lengthwise, the handle assembly moves past the locking feature, and the locking blade pushes the handle assembly back down alongside the locking feature which then prevents reverse sliding of the cover back from under the barrel tabs. When the handle is pulled to initiate removal of the cover, the handle assembly is then moved out above the locking feature to enable the cover to be slid to the released position. An automation apparatus interacts with one form of the locking assembly to automatically install and remove the cover.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of provisional Ser. No. 60/193,189, filed Mar. 30, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention concerns metal finishing barrels used in the cleaning, plating, phosphating, etc. of metal parts in bulk. 
     A material which will not be attacked by the various processing solutions such as polypropylene or stainless steel is typically used to construct metal finishing barrels, which are perforated so as to allow the parts to be immersed when the barrel is lowered into a tank of a plating or other processing solution. The finishing barrel is rotatably mounted on a support structure to allow it to be rotated while immersed in the tank to tumble the parts insuring even processing, and a gear is affixed to one end of the barrel for driving the barrel with an electric motor. 
     One or more removable covers are installed over a loading/unloading opening provided in the side of the barrel. The covers must be closely fit to the opening to insure that small parts will not be captured in clearance cracks or escape through gaps between the cover and the barrel. The covers must also be held securely to withstand the heavy loads imposed by the weight of bulk quantities of metal parts as the finishing barrel is rotated. 
     These requirements have led to the development of an interlocking tab cover securement in which a series of tabs on each side of the cover are slid beneath barrel tabs projecting towards the barrel opening to secure the cover in position. A separate cover locking system is needed to positively prevent the cover from shifting back to release the tabs during processing. This locking system has previously taken the form of a polypropylene nut piece threaded into a gap between two covers arranged in end to end alignment over the opening, preventing the covers from shifting back to disengage the tabs. 
     This arrangement has worked very well, but requires the threading and unthreading of the separate nut piece, significantly slowing the process of installing and removing the covers manually. Further, this system makes it difficult to automate the cover installation and removal process, which automation is often desirable. 
     Accordingly, it is an object of the present invention to provide a processing barrel cover locking system which is positive and secure but does not require separately installed locking system components to speed up the installation and removal of the covers. 
     It is a further object to provide such a cover locking system which is readily compatible with an automated cover handling system. 
     SUMMARY OF THE INVENTION 
     The above recited objects of the invention, as well as other objects which will be understood upon a reading of the following specification and claims, are achieved by mounting a cover handle assembly including a spring blade attached at one end to the cover. The cover and barrel are each formed with a series of interfit tabs, which allow the cover to be placed into the barrel opening with the tabs offset. When the cover is slid in one direction, the cover tabs are positioned lying partially beneath the barrel tabs to be interengaged and hold the cover over the barrel opening. 
     The handle assembly is aligned between successive cover tabs to engage a barrel tab when the cover is pushed into place over the barrel opening, but the spring blade mounting allows the handle to be moved out to allow the cover to be advanced so that the cover tabs are positioned beneath the barrel tabs. The cover is then slid to a tab engaged position with the cover tabs partially lying beneath the barrel tabs to secure the cover in position over the barrel opening. 
     When the handle is released, the spring blade causes the handle assembly to move back down against the cover, with the handle assembly then located just to one side of the barrel tab. The handle assembly has a blocking portion which is then located to one side of that barrel tab, acting to block any reverse shifting of the cover back out from under the barrel tabs, to positively lock the cover in the secured position. 
     The handle assembly moves away from the cover when the handle is pulled as the cover is being removed against the force generated by the spring blade, to elevate the handle blocking portion above the barrel tab. 
     This outward movement of the handle assembly allows the cover to be slid back out from under the barrel tabs and then lifted off the barrel opening. 
     Either one or two covers can be employed, with one cover having a locking handle securing the other cover in position by an end to end abutment of the covers. 
     This cover locking system can be employed with an automated process of installing and removing the cover. In this application, the cover handle assembly comprises a rod cammed out by a cam on a slide, which also advances a series of rods into bores in respective upright pieces attached to the cover. The cover and rod slides are then advanced further in the same direction by another actuator and slide to move the tabs out of engagement and allow the cover to be lifted out by motion of a third slide and actuator. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top view of a metal finishing barrel assembly and support structure incorporating a cover lock system according to the invention. 
     FIG. 1A is an enlarged top view of a portion of the barrel assembly shown in FIG.  1 . 
     FIG. 2 is a fragmentary end view of the finishing barrel assembly shown in FIG.  1 . 
     FIG. 3 is an enlarged fragmentary sectional view taken through the barrel and cover with the handle assembly shown in the locked condition. 
     FIG. 3A is the same view as FIG. 3 but shows the handle assembly in the released position. 
     FIG. 4 is a perspective view of a second embodiment of the finishing barrel assembly including a cover locking system according to the invention. 
     FIG. 4A is a fragmentary sectional view of the top portion of the barrel assembly shown in FIG.  4 . 
     FIG. 5 is a fragmentary end view of the barrel assembly shown in FIG.  4 . 
     FIG. 6 is an enlarged perspective view of the locking handle assembly and portions of the cover and barrel shown in FIGS. 4 and 5. 
     FIG. 7 is an end view of a finishing barrel assembly loaded in a transfer shuttle cart and positioned adjacent to an automated cover handling apparatus. 
     FIG. 8 is a front elevation view of the barrel assembly and a support structure therefor. 
     FIG. 9 is a front elevational view of the cover handling apparatus components for engaging the barrel cover, shown in section, portions of the barrel shown in phantom lines. 
     FIG. 10 is a front elevational view of the barrel assembly positioned in front of the cover handling apparatus diagrammatically depicting a shuttle mounted motor for rotating the barrel assembly to a predetermined located rotary position. 
     FIG. 11 is a front view of the cover handling apparatus utilized for lengthwise location of the barrel assembly partially shown in phantom lines. 
     FIGS. 12 and 13 are fragmentary sectional views through the barrel assembly and the cover handling apparatus showing cover engagement, shown rotated out of its actual inclined position to a vertical position for clarity. 
     FIG. 14 is an enlarged plan view of a fragmentary portion of the barrel assembly showing the locking handle assembly. 
     FIG. 15 is a view of the section  15 — 15  taken in FIG.  14 . 
     FIG. 16 is a sectional view taken through one of the rod engagement pieces attached to the barrel cover. 
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, certain specific terminology will be employed for the sake of clarity and a particular embodiment described in accordance with the requirements of 35 USC 112, but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims. 
     Referring to the drawings and particularly FIG. 1, a metal finishing barrel assembly  10  is shown of a well known type, including a perforate barrel  12  rotatably supported on a support structure  8 . A large polypropylene gear  16  is affixed to one end for rotating the barrel  12  while immersed in a solution in a processing tank (not shown) for uniform treatment of metal parts, using motor driving gears  15 ,  17  in the well known manner. 
     The barrel  12  has a lengthwise loading/unloading access side opening  18  (FIG. 2) formed therein of a generally rectangular shape. A perforate cover  20  is fit into the opening  18  and secured therein after the parts to be processed have been loaded. The opening  18  is defined by two rectangular frame pieces  22  having slots receiving the barrel wall  13 . The barrel wall  13  shown is constructed of one half inch thick polypropylene plastic which has been stress relieved. Holes are drilled into the barrel wall  13  and cover  20  to allow the plating or other solutions to freely enter the barrel to reach the parts loaded therein. 
     A pair of handle assemblies  26 ,  28  are attached to the cover  20  for manually lifting the cover  20  into and out of the opening  18 . 
     The handle assembly  28  incorporates features comprising part of a self acting cover locking system according to the invention, described below. 
     The frame  22  defines a ledge  24  on which the bottom of the cover  20  rests when placed over the opening  18 . A series of spaced barrel tabs  30  are arrayed along the length of each side of the opening  18  projecting inwardly towards the opening  18 . A corresponding series of spaced cover tabs  32  are arrayed along each side of the cover  20 . 
     The tabs  30 ,  32  are configured so that in an offset position, the cover tabs  32  can pass between the barrel tabs  30  so as to position the cover tabs  32  below the barrel tabs  30 , the cover  20  resting on the ledge  24 . 
     When the cover  20  is shifted to the left as shown in FIG. 1, the cover tabs  32  move to a position lying partially beneath the barrel tabs  32 , to secure the cover  20  over the opening  18 . Thus, portions of the cover  20  and barrel  12  are interfit by a endwire sliding movement of the cover to secure the cover over the opening  18 . 
     The locking handle assembly  28  includes a spring blade  34  (FIGS. 1A,  3 ,  3 A) fixed at one end to the cover  20  by a clamping block  36  and titanium screws  38 . A handle piece  40  is attached to the free end of the spring blade as by titanium screws  42 . A restraint piece  44  is secured to the cover  20  intermediate the length of the spring blade  34  limiting its upward movement and preventing any substantial sideways movement. 
     The cover  20  is lifted by grasping the handles  26  and  40  and placed over the opening  18  with the cover tabs  32  aligned with the gaps  46  between the barrel tabs  30 . 
     The cover  20  is pushed down into the opening  18 . The locking handle piece  40  is aligned with a barrel tab  30  in this position, but is deflected away as the cover  20  is seated on the lip  24  to accommodate movement of the cover tabs  32  below the barrel tabs  30  (FIG.  3 A). 
     Next, the cover  20  is slid to the left as seen in FIG. 1, until the left end abuts the gear end  16  of the barrel  12 . In this position, the cover tabs  32  are partially overlain by the barrel tabs  30  to capture the cover  20  in the barrel opening  18 . In this position, the handle piece nose  48  (FIGS. 3,  3 A) lies aligned with a gap  46  (FIG. 1A) between two barrel tabs  30 . Thus, when the handle  40  is released, the force of the deflected spring blade  34  pushes the nose portion  48  down to the left of the adjacent barrel tab  30 . The barrel tab  30  thus acts as a locking element with respect to the nose portion  48 , preventing the cover  20  from shifting to the right to unlock the cover tabs  32  from the position lying beneath the barrel tabs  30 . 
     Accordingly, a positive locking action is achieved without any further action than that required to secure the cover  20  in place. 
     Heavier duty metal finishing barrels are utilized in some processes, as in phosphating, and are typically constructed of metal such as stainless steel instead of plastic. FIGS. 4-6 show such a barrel assembly  50  including the barrel  52  and two covers  54 A,  54 B aligned end to end over a lengthwise opening  56  in the side of the barrel  52 . The covers  54 A,  54 B shown are of polypropylene while the barrel  52  is made of stainless steel, but the covers  54 A,  54 B could be also made of stainless steel to minimize thermal growth and chemical expansion to avoid any tendency for wedging of the covers in place if higher temperature conditions are present. 
     A series of metal channels  58  are attached to each cover  54 A,  54 B as shown in FIG.  4 A. Angles  60 ,  62  insure a snug fit of the covers  54 A,  54 B. 
     A (stainless steel) frame  64  is welded to the barrel  52  defining the opening  56 , with a spacer square bars  66  welded atop the frame  64  to support a series of barrel tabs  68  welded thereto. 
     Each end of each channel  58  is cut off at an angle A, and a bottom portion forms a cover tab  70  adapted to be slid below a corresponding barrel tab  68  as best seen in FIG.  4 . 
     Each cover  54 A,  54 B has a pair of handles  72  welded to respective channels  58 , enabling manual lifting of each of the covers  54 A,  54 B. 
     One of the channels  58 A has a spring blade  74  mounted within it, anchored at one end by one of the attachment bolts  73  for the channel  58 A itself (FIG.  6 ). The spring blade  74  extends within the channel  58 A and projects beyond the opposite end. A bolt  76  passes through a hole in the spring blade  74  and the channel  58 A, allowing up and down movement of the free end of the spring blade  74 , but restraining, sideways movement. An angle  78  is welded to the top of the spring blade  74  and serves as a handle to lift the spring and limits the extent of up and down movement. 
     A stop block element  80  is welded next to a barrel tab  68 , which element  80  is aligned with the projecting end of the spring blade  74  when the cover tabs  70  are aligned with the spaces to the right of the barrel tabs  68  when installing the cover  54 B. The spring blade  74  deflects upwardly when the cover  54 B is pushed down over the opening  56  as seen in FIG.  6 . 
     Referring to FIGS. 7-16, a version of the cover lock system for use with an automated, power operated apparatus for removing and replacing the cover is shown, along with an embodiment of the automation apparatus. 
     A metal finishing barrel assembly  82  is of the type described above is transported by a shuttle cart  84  between the processing system in which it is used and a cover removal-installation station (FIG.  7 ). 
     The barrel assembly  82  is rotatable on a support structure  94  (FIG.  8 ), driven by gearing  96  and a drive motor  98  (depicted diagrammatically) carried on the cart  84 . The barrel assembly  82  is rotated thereby to a rough located position by use of a target and sensor (not shown), where the cover  124  is approximately located opposite a cover engagement slide  102  moveable upwardly at an angle, the angled slide  102  part of cover removal and installation apparatus  104 . 
     The shuttle cart  84  is driven into the cover handling station with a pair of end locators  106 ,  108  (FIG. 11) spread apart prior to moving the engagement slide  102  and a platform  110  towards the barrel assembly  82  on slides  112  by an actuator  114  (FIG.  7 ). 
     The barrel assembly  82  is located endwise with respect to platform  110  which carries slide  102  by first moving the locator  106  toward the right against the left or idle end face of barrel assembly  82  by first actuator  116  as shown in FIG.  11 . After said contact is made, further travel of locator  106  is prevented by the weight resistance of the barrel assembly  82 , such that further travel of actuator  116  instead causes platform  110  which carries slide  102  and locator  108  to move toward the left on slides  120 , forcing the second locator actuator  118  to retract (which is allowed by connecting the actuator  118  to drain), until locator  108  contacts the right or gear end face of the barrel assembly  82 . At this point the barrel assembly  82  is located precisely in front of the cover handling apparatus  104 , regardless of the initial non-precise positioning of the barrel assembly  82  by the shuttle cart  84  relative to the cover removal and installation apparatus  104 . 
     The barrel assembly  82  is then rotated to a “fine” located position by operation of the motor  98 , using a second target and sensor (not shown) to accomplish this. 
     In this version, a series of aligned upright pieces  122  (FIG. 8) are attached to the cover  124 , each formed with a chamfered through bore  126 . A single locking handle assembly  128  provided. 
     The cover  124  has a series of tabs  130  projecting outwardly along each side. 
     The barrel  134  has a series of tabs  132  projecting inwardly towards a rectangular loading access  136  opening in the barrel side defined by a frame  138  (FIGS.  12 - 16 ). 
     The cover  124  can be placed on the barrel opening  136  atop the frame  138  by aligning the cover tabs  130  with the spaces between the barrel tabs  132  as in the above described embodiments and then sliding the cover  124  endwise to carry the cover tabs  130  beneath the barrel tabs  132  (FIG.  14 ). 
     Both the installation and removal is done automatically in this apparatus. 
     With the cover  124  in a locked position on the barrel  134 , and with the barrel assembly  82  precisely located endwise and rotationally, an actuator  138  is activated to carry the cover engagement angle slide  102  down onto the cover  124  (FIGS. 9,  11 ). In this position, a fork piece  142  (FIG. 9) captures one of the upright pieces  122 , while rod carriers  144  are located to the right of each upright piece  122 , respective rods  146  each being aligned with a respective chamfered bore  126 . The rod carriers  144  are all supported on a pair of lengthwise extending rods  148 , which are in turn supported on a lengthwise slide  150  supported on guides  151 . 
     A first lengthwise actuator  152  fixed to slide  150  has a movable output rod  154  which drives all of the rod carriers  144  to the left against stops  145  and fork piece  142  (FIG.  9 ), seating the rods  146  in their respective aligned bores  126  in the upright pieces  122 . 
     A second lengthwise actuator  156  is connected to the slide  150 , with an output rod  158  connected to the structure  102 . 
     The handle assembly  128  (FIGS. 14-16) includes a rod holder  160  fastened to a free end of a spring blade  162  with titanium screws  164 . The spring blade  162  is fastened to the cover  124  at its opposite end with a clamping piece  164  by titanium screws  166 . A side to side and outward restriction on the movement of the spring blade  162  is provided by a U-shaped piece  168  fastened to the cover  124  with titanium screws  170  at a point intermediate the length of the spring blade  162 . An opening  172  is sized to prevent side to side movement while allowing a predetermined extent of outward deflection of the free end of the spring blade  162 . 
     A cam rod  180  extends back over the cover  124  from one side of the rod holder  160  (cam rod  180  may also be grasped as a manual handle). 
     The cover tabs  130  are sized to fit between spaces  182  between the barrel tabs  132  when the cover  124  is positioned to align the same at the beginning of the cover removal cycle. 
     The rod holder  160  is urged down by the spring blade  162  to normally occupy one of the barrel tab spaces  182 , which thus engages an adjacent barrel tab  132 A, preventing the cover  124  from shifting back to allow the cover tabs  130  to move out from under the barrel tabs  132 . 
     When the actuator  152  moves the rods  148  to the left, a cam piece  184  mounted thereon (FIG. 9) is also driven to the left to engage the cam rod  180 , forcing the cam rod  180  to move out as seen in FIG. 12, moving the rod holder  160  away to clear the adjacent barrel tab  132 . 
     When activated, the actuator  156  causes the slide  150  to move to the left to carry the rods  148 , cover  124 , and rod carriers  144  to the left, sliding the cover tabs  130  out from under the barrel tabs  132 . 
     The locator actuators  116 ,  118  are operated to spread the locators  106 ,  108  out of engagement with the barrel  134 . 
     The actuator  138  is then operated to move the cover  124  off and away from the barrel  134 , actuator  114  retracting all of these parts and the cover  124  back. 
     The barrel  134  is then unloaded and then reloaded with parts, and the cover  124  replaced by the reverse of the cycle described. 
     In placing the cover  124  onto the barrel  134 , the handle rod holder  160  engages a barrel tab  132 A and the spring blade  162  deflects to allow the rod holder  160  to move out as the cover  124  is advanced over the barrel opening  136 . As the cover  124  is slid lengthwise, the rod holder  160  is moved back in by the spring blade  162  to be positioned adjacent a barrel tab  132 A to lock the cover  124  in the secured position.