Patent Publication Number: US-6705233-B2

Title: Expandable painting wagon having a rack and pinion drive mechanism

Description:
This application claims the benefit of Provisional application No. 60/210,881 filed Jun. 9, 2000. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a paint wagon for carrying a plurality of components to be painted through a painting facility. In particular, this invention relates to an expandable paint wagon which can be easily expanded and contracted at desired locations. 
     BACKGROUND OF THE INVENTION 
     Paint wagons are commonly used to carry exterior components of motor vehicles through a paint facility. U.S. Pat. No. 5,772,233 describes a typical paint wagon used for two tone fascias. The paint wagon contracts prior to entry into the paint facility so that one fascia will partially shroud a next adjacent fascia. After painting, the wagon expands to allow removal of the fascia from the wagon. 
     More commonly, paint wagons are not expandable and have mounting fixtures which are rigidly mounted to the wagon. These wagons are used primarily because they are easy to build and have no moving parts which can foul with each trip through the paint facility. However, fixed mount paint wagons limit the throughput of the paint facility since each wagon requires a minimum of space along the conveyor to allow the wagons to run corners. In many cases, the fascia must be spaced apart to allow the painting robot to fit between the parts and to allow the mounting and removal of the fascia onto and from the paint wagon. At other times, the non-expandable wagons take up valuable space along the conveyor system. 
     The expandable wagon as described in U.S. Pat. No. 5,772,233 could easily be modified to expand prior to entry into the paint facility and contract after and at other desired locations. However, the prior art expandable wagons require contact with a fixed rigid structure to expand and contract. Usually, a pole is mounted on the floor adjacent the travel of the paint wagons to effect the movement of the paint wagon. Although a number of poles could be installed about the conveyor, these poles would present safety problems. Further, the greater number of poles may interfere with other fixtures mounted on the paint wagons. Other fixtures are utilized when parts other than fascia are required to be painted. Thus, the addition of poles is not a safe and economical solution to modifying paint wagon length. 
     SUMMARY OF THE INVENTION 
     The disadvantages of the prior art may be overcome by providing an expandable paint wagon having a simple actuating mechanism which can be triggered by a low profile mechanism. 
     According to one aspect of the invention, there is provided a paint wagon which has a base having a plurality of wheels mounted in supporting relation thereto. A drop pin is slidably mounted to the base. The drop pin selectively engages with a conveyor for translating the paint wagon along a path. A plurality of slidably mounted mounting fixtures is movable between a contracted position and an expanded position. An actuating assembly slidably mounts the mounting fixtures to the base. The actuating assembly has a longitudinal support and a plurality of cars in sliding engagement with the longitudinal support. The mounting fixtures extend from the plurality of cars. A rotatably mounted pinion drivingly engages a rack which is slidably mounted with the longitudinal support. The rack is connected to an outer car. The rack has a plurality of tabs extending therefrom positioned to selectively engage inner cars to move the inner cars and automatically space the cars. An actuating mechanism is mounted on the path. The actuating assembly selectively engages the actuating mechanism as the paint wagon travels along the path to effect rotation of the pinion and responsively effect the movement of the mounting fixtures between the contracted and expanded positions. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred embodiment of the invention will now be described, by way of example only, with reference to the attached Figures, in which: 
     FIG. 1 is a perspective view of a paint wagon with actuating mechanism of the present invention; 
     FIG. 2 is a perspective view of the paint wagon and actuating mechanism of FIG. 1; 
     FIG. 3 is a partial sectional view of the actuating assembly of the paint wagon of FIG. 1; 
     FIG. 4 is a partial perspective view of the actuating assembly of the paint wagon of FIG. 1; 
     FIG. 5 is a partial perspective view of the actuating assembly of the paint wagon of FIG. 1; 
     FIG. 6 is a partial perspective view of the locking mechanism of the actuating assembly of the paint wagon of FIG. 1; 
     FIG. 7 is a perspective view of the actuating mechanism of the paint wagon of FIG. 1; 
     FIG. 8 is a top plan view of the actuating mechanism of FIG. 7 in an engaged position; 
     FIG. 9 is a top plan view of the actuating mechanism of FIG. 7 in a disengaged position; 
     FIG. 10 is a side schematic view of the actuating assembly of the paint wagon of FIG. 1, moving to an expanded position; and 
     FIG. 11 is a side schematic view of the actuating assembly of the paint wagon of FIG. 1, moving to a contracted position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, an expandable paint wagon  10  of the present invention is shown. The paint wagon  10  travels along a conveyor  12  in the direction indicated at  14 . The conveyor  12  is conventionally mounted below floor  16  and accessed through a slot  18 . 
     An actuating mechanism  20  is mounted on the floor  16  adjacent to the slot  18 . Actuating mechanism  20  is generally elongate and extends in the same general direction as the slot  18 . 
     Referring to FIG. 2, the paint wagon  10  is illustrated in greater detail. The paint wagon  10  generally comprises a base frame  22 , an actuating assembly  24  and a fixture mounting assembly  26 . Actuating assembly  24  is mounted on the base frame  22 . Fixture mounting assembly  26  is operably mounted on the actuating assembly  24  for responsive movement between an expanded condition (FIG. 2) and a contracted condition (FIG.  1 ). 
     Base frame  22  is preferably an H-shaped frame having wheel assemblies  28 ,  30  suitably mounted at each of the four legs of the H-shaped frame to support the paint wagon  10 . Preferably wheel assemblies  28  are caster wheels which allows the paint wagon  10  to be guided along and steered. 
     A drop pin  32  is slidably mounted at the front of the frame  22 . The drop pin  32  extends downwardly to engage a socket  34  on the conveyor chain  12 . When engaged with the conveyor chain  12 , the drop pin  32  provides a driving engagement to the paint wagon  10  to translate the paint wagon  10  along floor  16 . The drop pin  32  is lifted to disengage the paint wagon  10  from the conveyor chain  12 . 
     Referring to FIGS. 3 and 4, the actuating assembly  24  comprises an elongated C-shaped longitudinal support  38  having closed ends  40 . Longitudinal support  38  is mounted on spacers  36 . An elongate channel  42  extends longitudinally along one side of the longitudinal support  38 . The upper edge  44  and the lower edge  46  of the channel  42  define guides. A fixed plate  48  is welded to the longitudinal support  38  across the open channel  42 . Stationary mounting arm  50  extends from plate  48 . 
     Inner cars  52 , middle cars  54  and end cars  56  are mounted on the upper and lower guides  44 ,  46  for sliding movement outwardly and inwardly relative to fixed plate  48 . 
     Actuating assembly  24  is symmetrical about a diagonal across plate  48  and therefore only one side will be described in detail. 
     Each of the cars  52 ,  54 ,  56  has a mounting plate  58  on which rollers  60  are rotatably mounted. Preferably, four rollers  60  are spaced about one face of mounting plate  58  so that the rollers engage guides  44 ,  46 . The rollers  60  mount the cars  52 ,  54 ,  56  for guided travel along the actuating assembly. A mounting arm  62  extends outwardly from the mounting plate  58 . Cars  52 ,  54 ,  56  are identical except that inner cars  52  have a tab  64  projecting from the leading edge when the cars are moving in an expanding direction and middle cars  54  have a tab  66  projecting from trailing edge when the cars are moving in an expanding direction. Middle cars  54  and outer cars  56  each has a spacer bar  68  extending from the leading edge when the cars are moving in a contracting direction. 
     Actuating assembly  24  further comprises a pinion  70  mounting on a drive shaft  72 . Bevel gear  74  is also mounted on the drive shaft  72  on an end opposite pinion  70 . Bevel gear  74  drivingly engages a matching bevel gear  76  which is mounted on a vertically extending shaft  78 . Bearings  80 ,  82  are provided to journal mount shafts  72 ,  78 , respectively. 
     Racks  84 ,  86  are slidably mounted within longitudinal support  38 . The distal end of each rack  84 ,  86  is affixed to the outer cars  56 . Racks  84 ,  86  each has a set of teeth  88  along a near end thereof for engaging with pinion  70 . Racks  84 ,  86  extend in opposite directions on opposite sides of the pinion  70 . Rotation of pinion  70  in a first sense will move both racks  84 ,  86  outwardly in an expanding direction and rotation in the opposite sense will move both racks  84 ,  86  inwardly in a contracting direction. 
     Racks  84 ,  86  each has an inner tab  90  and a middle tab  92  (See FIGS. 10,  11 ). Middle tab  92  extends is a direction orthogonal from inner tab  90 . Tabs  90 ,  92  are spaced at a distance to provide a desired separation between parts to be painted. Inner tab  90  will contact tab  64  on inner cars  52  when the racks  84 ,  86  are moving in the expanding direction and urge the inner cars  52  in the expanding direction. Middle tab  92  will contact tab  66  on middle cars  54  when the racks  84 ,  86  are moving in the expanding direction and urge the middle cars  54  in the expanding direction. Middle tab  92  and inner tab  90  are orthogonal so that the racks  84 ,  86  will only engage the middle cars  56  and the inner cars  52 , respectively, during expanding movement and not during contracting movement. 
     Referring to FIGS. 5 and 6, the lower end of shaft  78  has a spur gear  94 . Mounted in front of and parallel to shaft  78  is a lock shaft  96 . Lock shaft  96  has a floor engaging roller  98  at the lower end and a section of a bevel gear  100  at the upper end. A spring  102  mounts between the housing  104  and the lock shaft  96  to bias the lock shaft to the down or lock position. Lock shaft  96  has a key  106  which prevent rotation of the lock shaft and limits movement to the vertical direction. In the lock position, bevel gear  100  engages bevel gear  76  to prevent rotation thereof. 
     Referring to FIG. 7, the floor mounted actuating mechanism  20  is illustrated in greater detail. The cover  108  has been removed to show the inner detail. Bar  110  is pivotally mounted on cover  18  near the leading edge thereof. Bar  110  has a ramp  109  and an elevated surface  107  for receiving roller  98  of lock shaft  96  and urging the lock shaft  96  upwardly to the raised position and to unlock the actuating assembly  24 . Bar  110  has a spring  111  extending between the trailing end and the cover  108 . A shock absorber  113  also extends from the trailing end and the cover  108 . The spring  111  and shock absorber  113  control the pivotal movement of the bar  110 . 
     A sleeve  112  is slidably mounted on bar  110  for travel in the direction of travel  14 . A spring  114  extends between the sleeve  112  and bar  110  and urges the sleeve towards the leading edge of the cover  108 . A shock absorber  116  is pivotally mounted at one end to the sleeve  112  and pivotally mounted at the opposite end to the cover  108 . Sleeve  114  has an abutment  118  at the trailing end thereof. Sleeve  112  has an L-shaped flange  120  having a rack of teeth  122  which are complementary to and operatively engage the bevel gear  94 . The leading edge of the rack of teeth  122  is slightly tapered to allow smooth engagement between the teeth  122  and bevel gear  94 . 
     Cover  108  has a stop  124  positioned near the trailing end of the cover  108 . Bar  110  will rest against the stop  124  under the influence of spring  111 . Stop  124  will also engage abutment  118  of sleeve  112  as the sleeve  112  is moved towards the trailing end which will cause the sleeve  112  and the rack of teeth  122  to pivot outwardly to disengage the rack of teeth  122  from the bevel gear  94 . 
     Cover  108  is firmly attached to the floor  16 , adjacent the slot  18 . Cover  108  is generally a C-shaped extrusion having an open channel facing upwardly and extending in the direction of travel. The leading edge of the slot is preferably tapered to receive lock shaft  96 . 
     Referring back to FIG. 2, the fixture mounting assembly  26  comprises a plurality of U-shaped supports  126 . Each of the supports  126  are mounted on one of the fixed arm  50  or movable arms  62 . In the preferred embodiment, the paint wagon has seven mounting fixtures, six movable fixtures and one stationary fixture. It is apparent to those skilled in the art that any number of fixtures could be accommodated. 
     Housing  104  shrouds the gear or operating components of the paint wagon  10  from paint over spray. Preferably, cars  52 ,  54  and  56  are made from stainless steel in order to minimize damage from the paint and the requisite cleaning solvents needed to clean and remove over sprayed paint. The preferred shape of mounting arms  62  is as illustrated in FIG.  2 . The shape allows a further shroud to be placed over the channel  42  further minimizing the risk of paint being applied to the cars  52 ,  54  and  56 . 
     In operation, the paint wagon  10  of the present invention is selectively engaged to the conveyor  12 . The paint wagon  10  will be pulled about in the direction of travel  14 . In this condition, the lock shaft  96  will be in the down or locked position, holding the fixture mounting assembly  26  in place in the contracted condition. The paint wagon  10  will encounter one of a desired number of actuating mechanisms  20 . 
     Referring to FIG. 5, the roller  98  will engage the ramp  109  which will lift the lock shaft  96  upwardly, disengaging the bevel gear  94  of the actuating assembly  24 . As the paint wagon  10  travels along, spur gear  94  will engage rack of teeth  122  which will cause rotation thereof in an expanding sense. Rotation of spur gear  94  will in turn rotate pinion  70 , which in turn will cause outwardly movement of the racks  84 ,  86 . 
     Referring to FIGS. 10 and 11, the outward movement of the racks  84 ,  86  will cause direct movement of the outer cars  56 , since racks  84 ,  86  is directly connected to one of the outer cars  56 . Inner tab  90  and middle tab  92  will contact tabs  64  and  66 , respectively, to move cars  52 ,  54  to each respective expanded position. 
     Referring to FIGS. 7,  8  and  9 , the disengagement of the actuating mechanism  24  is illustrated. Once the paint wagon  10  has reached the expanded position, the racks  84 ,  86  will stop moving. This will cause pinion  70  to stop rotating and in turn stop spur gear  94  from rotating. If the spur gear  94  has not disengaged from the rack of teeth  122 , the spur gear  94  will cause the rack of teeth  122  and sleeve  112  to slide along the bar  110  until abutment  118  engages stop  124 . Engagement of the abutment  118  with stop  124  will cause bar  110  and the sleeve  112  to pivot outwardly to cause the rack of teeth  122  to disengage from the spur gear  94 . Once the spur gear  94  has traveled beyond the rack of teeth  122 , the spring  111  will return the bar  110  and sleeve  112  back to a ready position in parallel to the direction of travel  14 . Once the paint wagon  10  has traveled beyond the bar  110 , the lock shaft  96  will fall off the trailing edge of the bar  110  allowing the lock shaft to move downwardly to the lowered position to re-engage the bevel gear  100  with the bevel gear  76 , locking the actuating assembly  24  in place. 
     To contract the paint wagon  10 , an actuating mechanism  20  is mounted on the floor  16 . The contracting actuating mechanism  20  is a mirror image of the mechanism shown in the FIGS. 7,  8 , and  9 . The rack of teeth  122  will be on the opposite side of the bar  110  and will rotation of the spur gear  94  in a contracting sense opposite the expanding sense. 
     Rotation of the spur gear  94  in the contracting sense will cause rotation of the pinion  70  in the contracting sense. Pinion  70  will cause racks  84 ,  86  to move inwardly. Racks  84 ,  86 , will move the outer cars  56  inwardly which will urge middle cars  54  inwardly and then inner cars  52  inwardly to the contracted position. Bars  68  will space the outer cars  56  from the middle cars  54  from the inner cars  52 . By selecting the length of bars  68 , a minimum spacing between supports  126  is determined. 
     As is apparent, any number of actuating mechanisms  20  can be placed about the length of the conveyor  12  to expand and contract the paint wagon  10  as desired. Preferably, the paint wagons  10  are contracted to turn corners and expanded for painting, mounting and dismounting parts to be painted onto and from the paint wagon  10 . The actuating mechanisms  20  have a low profile minimizing risk of contact by fork lift trucks and workers. Additionally, actuating mechanisms  20  are mounted directly under the path of travel of the paint wagons  10  and therefore not in an area normally accessed by workers. 
     While presently preferred embodiments of the present invention are described herein, variations and modifications will occur to those skilled in the art and should not be considered as departing from the scope of the invention as defined by the appended claims. floor  16 . The contracting actuating mechanism  20  is a mirror image of the mechanism shown in the FIGS. 7,  8 , and  9 . The rack of teeth  122  will be on the opposite side of the bar  110  and will rotation of the spur gear  94  in a contracting sense opposite the expanding sense. 
     Rotation of the spur gear  94  in the contracting sense will cause rotation of the pinion  70  in the contracting sense. Pinion  70  will cause racks  84 ,  86  to move inwardly. Racks  84 ,  86 , will move the outer cars  56  inwardly which will urge middle cars  54  inwardly and then inner cars  52  inwardly to the contracted position. Bars  68  will space the outer cars  56  from the middle cars  54  from the inner cars  52 . By selecting the length of bars  68 , a minimum spacing between supports  126  is determined. 
     As is apparent, any number of actuating mechanisms  20  can be placed about the length of the conveyor  12  to expand and contract the paint wagon  10  as desired. Preferably, the paint wagons  10  are contracted to turn corners and expanded for painting, mounting and dismounting parts to be painted onto and from the paint wagon  10 . The actuating mechanisms  20  have a low profile minimizing risk of contact by fork lift trucks and workers. Additionally, actuating mechanisms  20  are mounted directly under the path of travel of the paint wagons  10  and therefore not in an area normally accessed by workers. 
     While presently preferred embodiments of the present invention are described herein, variations and modifications will occur to those skilled in the art and should not be considered as departing from the scope of the invention as defined by the appended claims.