This document relates generally to racks for holding and processing a group of parts and, more particularly, to a multipurpose rack for processing parts through multiple manufacturing processes.
Parts are often subjected to a number of different manufacturing processes before being assembled into a final product. For example, roof rails and other parts for a pickup truck are typically subjected to a heat treatment to increase strength and a chemical pretreatment to prepare the parts for receiving adhesive used to bond vehicle components together later in the assembly process.
In the past this has been done by loading parts onto a mild steel rack and then subjecting them as a group to heat treatment in an oven. Following heat treatment the parts have been unloaded from the mild steel rack and then reloaded onto a stainless steel rack for purposes of chemical pretreatment. Following chemical pretreatment the parts have been unloaded from the stainless steel rack and reloaded onto a clean rack for transport or transfer to the assembly area.
This document relates to a new multipurpose rack which can properly hold a group of parts for heat treatment, chemical pretreatment and transfer to an assembly area thereby eliminating the re-racking steps. Advantageously the multipurpose rack described in this document lowers production costs by eliminating re-racking, minimalizing the part handling, reducing damage caused by excessive part handling and improving the traceability of parts as they are processed. Further, it reduces the number of racks required for part processing thereby increasing useable floor space at the manufacturing plant. Floor space for the processing equipment is also greatly reduced as we can process multiple parts simultaneously, i.e. 48 and 68 depending on the rack used. Previous methods would have required one part at a time greatly increasing the foot print of the machine that would perform this process.
In accordance with the purposes and benefits described herein, a rack is provided for simultaneously processing a plurality of parts. The rack may be broadly described as comprising a frame, a plurality of defined locations on the frame for receiving and holding individual parts for processing and a latching assembly for locking the parts to the frame in the defined locations. The rack further includes a security feature for indicating if the latching assembly is opened after the parts have been loaded and locked into the defined locations on the frame. In addition the rack includes a unique ID code to identify the rack and the parts loaded and locked into the defined locations on the frame throughout the manufacturing process.
In one possible embodiment the frame includes a first post, a first upright, a second post, a second upright, a first support arm and a second support arm. The first support arm extends between the first post and the first upright and the second support arm extends between the second post and the second upright.
The first support arm includes a first plurality of part locating elements and the second support arm includes a second plurality of part locating elements. In one possible embodiment the first and second plurality of part locating elements comprise a plurality of spaced retaining grooves or scallops provided in the first and second support arms. In one possible embodiment, the frame further includes a first end plate having a third plurality of part locating elements. The third plurality of part locating elements comprise tabs received within open ends of the plurality of parts. Accordingly, the first, second and third locating elements locate a first group of parts in the defined locations on the frame so that no one part touches another part. This ensures that each part receives proper heat treatment and chemical pretreatment during processing.
In one possible embodiment the rack further includes a first retaining arm carried on the first post and displaceable between a part loading position and a part securing position. In one possible embodiment the rack further includes a second retaining arm carried on the second post and displaceable between a part loading position and a part securing position. The first group of parts is captured in the defined locations (a) between the first retaining arm and the first support arm and (b) between the second retaining arm and the second support arm when the first and second retaining arms are in the part securing positions.
In one possible embodiment the first retaining arm includes a fourth plurality of locating elements and the second retaining arm includes a fifth plurality of locating elements. Further, the frame includes a second endplate having a sixth plurality of locating elements. Together the fourth, fifth and sixth locating elements locate a second group of parts in defined locations on the frame so that no one part touches another part.
In still another possible embodiment the frame includes a third retaining arm connected to the first post and a fourth retaining arm connected to the second post. The third and fourth retaining arms are both displaceable between part loading and part securing positions. In this embodiment the second group of parts is captured in defined locations (a) between the third retaining arm and the first retaining arm and (b) between the fourth retaining arm and second retaining arm when the third and fourth retaining arms are in the part securing positions.
In one possible embodiment the latching assembly includes a first latching bar and a second latching bar. The first and second latching bars are displaceable between part loading and part locking positions. When the first and second latching bars are in the locking position, the first latching bar engages and closes end openings between the first support arm, the first retaining arm and the third retaining arm and the second latching bar engages and closes end openings between the second support arm, the second retaining arm and the fourth retaining arm. The latching assembly may also include (a) a first clevis pin for securing the first latching bar to the frame in the locking position and (b) a second clevis pin for securing the second latching bar to the frame in the locking position. Further the security feature may include (a) a first security tab connected to the first clevis pin so that the first clevis pin is captured in the frame by the first security tab and (b) a second security tab connected to the second clevis pin so that the second clevis pin is captured in the frame by the second security tab. In one possible embodiment the first and second security tabs are frangible and must be broken to pull the first and second clevis pins from the frame and allow displacement of the (a) first and second latching bars and (b) first, second, third and fourth retaining arms to allow removal of any parts from the rack.
In the following description, there is shown and described several preferred embodiments of the rack. As it should be realized, the rack is capable of still other, different embodiments and its several details are capable of modification in various, obvious aspects all without departing from the rack as set forth and described in the following claims. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not as restrictive.
The accompanying drawing figures incorporated herein and forming a part of the specification, illustrate several aspects of the rack and together with the description serve to explain certain principles thereof. In the drawings:
Reference will now be made in detail to the present preferred embodiments of the rack, examples of which are illustrated in the accompanying drawing figures.
Reference is now made to
As illustrated, the frame 12 includes a base, generally designated by reference numeral 20, comprising two side rails 22, two skids 24 connected to the side rails, two end rails 26 and one center rail 28. A “palate” is formed by four cross beams 30, each having a t-shaped cross section. The “palate” allows the rack to be engaged and lifted with the forks of a forklift truck (not shown).
The frame 12 further includes two opposing end assemblies 32. Each end assembly 32 comprises two corner posts 34, one center post 36, one upper cross rail 38 and one lower cross rail 40. A parts stand 42 is provided between the center post 36 and one of the corner posts 34 at each end of the rack 10. Each parts stand 42 comprises two runners 44 and four staggered end plates 46 for receiving and holding ends of the parts P in a manner that will be described in detail below.
A center beam 48, aligned with the center posts 36 and extending between the center posts and the upper cross rails 38 overlies the center rail 28. Four center posts 50 extend between the center rail 28 and center beam 48. The center posts 50 are centered on the rack 10 and overlie the “palate” formed by the cross beams 30.
As further illustrated in
As should be appreciated, each support arm 54 includes a plurality of part locating elements 56. In the illustrated embodiment the part locating elements 56 take the form of a plurality of spaced retaining grooves or scallops. Similarly, each plate 46 of the part stands 42 includes a plurality of part locating elements 58. In the illustrated embodiment the part locating elements 58 comprise spaced tabs.
Reference is now made to
Significantly, the tabs 58 receive and hold the open ends of the parts P so that they are directed downwardly. This promotes good, efficient drainage of the parts P during chemical pretreatment when they are removed from the treatment tanks 122 (see
Referring back to
As illustrated, the lowermost arm 60 is slightly shorter than the next highest arm 62, which is slightly shorter than the next highest arm 64, which is slightly shorter than the longest, uppermost arm 66. Further, each of the three lowermost arms 60, 62, 64 include a plurality of part locating elements in the form of grooves or notches 68.
Once the first layer of six parts P has been positioned and located on the support arms 54 and the lowermost, innermost part stand plate 46 (as illustrated in
The next row of parts P is now added to the rack 10. This is done by positioning the open ends of the next six parts on the six tabs 58 of the next highest, next innermost parts stand plate 46 and resting each part in the aligned retaining grooves 68 provided in the upper surface of the bottom most retaining arm 60. Once the six parts P of the next layer are positioned in this manner, the retaining arms 62 are pivoted from the part loading position to the part securing position. When in the part securing position the retaining arms 62 function to capture the second row of parts P in the retaining elements, grooves or notches 68 of the retaining arms 60.
Now a third row of parts P is added to each side of the rack 10. This is done by positioning the open ends of six parts P on the third parts stand plate 46 and resting the ends of the parts in the aligned cooperating parts retaining elements/grooves 68 in the retaining arms 62. Once all six parts P are properly positioned, the retaining arms 64 are pivoted from the parts receiving position to the parts retaining position. As should be appreciated, in the parts retaining position the retaining arms 64 overlie the parts in the third row thereby capturing the parts in the grooves 68 of the retaining arms 62. Thus the parts in the third row are maintained in defined locations on the frame 12 so that each individual part will not touch another part.
Now the final row of parts P is added to each side of the rack 10. To do this the open ends of six additional parts P are positioned over the tabs 58 in the uppermost parts stand plate 46 with the bodies of the parts received and resting in the aligned grooves 68 of the arms 64. When all six parts P of the fourth row of parts are properly positioned in their defined locations 14, the upper most retaining arms 66 are pivoted from the part loading position to the part securing position. As should be appreciated when the rack 10 is fully loaded and the retaining arms 60, 62, 64, 66 are all in the parts retaining position, all the retaining arms overlie the associated support arm 54 extending between the center post 50 to the cooperating, aligned upright 52. See
As best illustrated in
One latching bar 74 is slidably received on each upright 52 and is displaceable between the part loading position and the part locking position. The part loading position is illustrated in
As should be appreciated, the retaining grooves 56, 68 and the tabs 58 provide a defined location 14 for each part P. The overlying retaining arms 60, 62, 64, 66 ensure that each part P is maintained in those defined locations 14 where no one part touches another part.
During chemical pretreatment, the rack 10 is dipped into a tank containing a chemical solution. Air is often trapped in individual parts P during dipping creating a buoyancy that tends to lift the parts P from the grooves 56, 68 and tabs 58. The overlying retaining arms 60, 62, 64, 66 function to maintain the parts P in the defined locations 14 within the grooves 56, 68 and on the tabs 58 so that the parts will receive the full benefit of the treatment.
An alternative method of racking such parts would be in a vertical orientation to aid drainage; however such a configuration requires deeper chemical tanks, a larger oven and a larger pretreatment system. Another alternative is to rotate the rack as it is dipped and raised i.e. horizontal within the tank to reduce tank size and chemical volume but pivoted to vertical on entry and exit to aid drainage. Such a line is more complex, costly and slower in operation. Horizontal with a trapped air pocket is also advantageous as the inner surface does not require pretreatment, thereby saving chemical consumption and minimizing “drag-out”.
Reference is now made to
Reference is now made to
A forklift or other means then transfers the rack 10 and the parts P locked therein to the chemical pretreatment area generally designated by reference numeral 114. More specifically, the fork lift truck delivers the rack 10 and the parts P locked therein to the loading area 116 where the racks are loaded onto a conveyor which, in the illustrated embodiment takes the form of a monorail 118. The racks 10 and the parts P locked therein are then transferred or transported by the monorail 118 through the chemical pretreatment facility 120. There the rack 10 and the parts P locked therein are dipped into the various treatment tanks 122 in order to complete the chemical pretreatment of the parts. The monorail 118 then delivers the racks 10 and the parts P held therein to the drying oven where the parts P and the rack 10 are dried before being delivered to the unloading station 126. A forklift truck or other means is then used to transfer or transport the racks 10 and the parts P locked therein to the assembly area 128 where the parts are removed from the rack and readied for vehicle assembly.
As should be appreciated, the parts P are locked into the rack 10 by means of the retaining arms 60, 62, 64, 66 and the latching assembly 16 including the latching bars 74 and clevis pin 76 at the rack loading area. The integrity of the processing of the parts P in the rack 10 through the heat treatment and chemical pretreatment process is ensured by the security tabs 80. More specifically, these security tabs 80 are inserted in the ends 78 of the clevis pins 76 and locked at the rack loading area 102 (before heat treatment). When the rack 10 reaches the assembly area 128, whole unbroken security tabs 80 indicate that all parts P in the rack 10 were properly subjected to heat treatment and chemical pretreatment. In contrast, if one of the frangible security tabs 80 is broken, that indicates the possibility that one or more parts P in the rack 10 did not undergo proper heat treatment or chemical pretreatment and, accordingly, the parts in that rack may be set aside for verification of proper heat treatment and chemical pretreatment processing where required. Thereby the security tab 80 ensures the integrity of the processing of the parts P. It should be noted that not all parts require the heat treatment step. For example, the roof rails that require high strength are heat treated post forming in order to artificially age the alloy and increase yield strength. Front rails are required to have lower yield and greater ductility to absorb energy in a frontal crash. For this reason, front rails are not heat treated and are therefore taken from the rack loading area 102, by fork truck, to the pretreated loading area 116. Such a configuration allows different alloys with differing heat treatment requirements to be processed through the same line.
In one particularly useful embodiment of the invention, each rack 10 includes a plate 15 bearing a unique ID code to identify the particular rack 10 (see
The foregoing has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. Obvious modifications and variations are possible in light of the above teachings. All such modifications and variations are within the scope of the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.