BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic top plan view of a vehicle body assembly line that embodies the present invention and performs a method of vehicle body assembly in accordance with the invention.
FIG. 2 is a perspective view of a work pallet for use in assembling vehicle body formed metal parts in accordance with the invention.
FIG. 3 is a top plan schematic view for illustrating the operation of adjustable locators on the work pallets of the assembly line.
FIG. 4 is a perspective view taken from an outboard direction of one of the adjustable locators of the work pallets.
FIG. 5 is a perspective view of the adjustable locator taken from an inboard direction.
FIG. 6 is a schematic view that illustrates a control brake utilized with linear bearings of the adjustable locators.
FIG. 7 is a schematic view illustrating a sensor used to provide any required locator positioning adjustment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIG. 1 of the drawings, a vehicle body assembly line generally indicated by 10 includes a schematically indicated conveyor 12 for conveying work pallets 14 during assembly of formed metal parts to each other to provide vehicle bodies. During such assembly, the work pallets 14 are conveyed by the conveyor 12 in a clockwise direction starting at an initial adjusting station 16 where adjustable locators 18 (FIG. 2) are adjusted as is hereinafter more fully described. From the adjusting station 16 shown in FIG. 1, the work pallets 14 are conveyed toward the right to a front floor panel supply station 20, then to a center floor panel supply and assembly station 22, then to a rear floor panel supply and assembly station 24 where the assembly is completed, and finally to an unload station 26 prior to continued clockwise movement to the left along a return run back to the adjusting station 16. The adjustment of the locators 18 of work pallets 14 at the adjusting station 16 permits the assembly line to accommodate vehicle body assembling of different models and can also provide adjustment of each work pallet after each assembly cycle so as to ensure that the locators are properly located in preparation for the next cycle.
The vehicle body assembly line construction, the work pallet construction and the vehicle body assembling method of the invention will be described in an integrated manner to facilitate an understanding of all aspects of the invention. Also, it is should be appreciated that while the assembly line is disclosed as assembling front, center and rear formed sheet metal floor parts 28, 30 and 32 as shown in FIG. 3, the assembly can also be performed with other formed metal parts, such as, for example, assembly of longitudinal frame members to formed sheet metal body panels.
As shown in FIG. 3, each work pallet 14 includes a carriage 34 on which the adjustable locators 18 are mounted. Each locator as shown in FIGS. 4 and 5 and schematically in FIG. 7 includes a locator member 36 having a vertical rest surface 37 mounted thereon and a locator pin 38 also mounted thereon and extending upwardly from vertical rest surface 37 mounted on the locator member to be capable of providing part positioning of the assembly. More specifically, the vertical rest surface 37 of each locator member 36 is adjustable vertically and supports the parts being assembled to provide positioning in a vertical direction, i.e. the Z direction shown in FIG. 3. Furthermore, the locator member 36 is horizontally adjustable so its locator pin 38 is capable of providing positioning of the parts in longitudinal and sideways directions as respectively illustrated by X and Y in FIG. 3. Each locator member 36 as shown in FIG. 4 has a grab member 40 that is located at a remote position below the mounting location of its vertical rest surface 37 to provide the adjustment as is hereinafter more fully described. A linear support bearing 42 shown in FIGS. 4 and 5 supports the locator member 36 for adjusting movement of its vertical rest surface and associated locator pin 38. As specifically shown in FIG. 5, the locator member 36 is directly supported by a vertical linear bearing 42z which is in turn supported by a sideways linear support bearing 42y that is supported by a longitudinal support bearing 42x. Each of these linear support bearings as shown in FIG. 6 includes a bearing rod 44 and a brake 46 that has a locked condition for holding its locator member in an adjusted position along its associated direction and also has an unlocked condition where the locator member thereof is freely movable for adjustment along the axis of its linear bearing.
For some low production vehicle body assembly lines, it is possible to utilize manual grasping of the grab member 40 of each locator member 36 as shown in FIG. 4 to permit adjustment to the required position along the vertical Z axis and, as shown, likewise along the sideways Y axis and the longitudinal X axis. For higher production assembly lines, it is preferable to utilize an adjuster 48 as shown in FIG. 1 at the adjusting station. Regardless of whether a manual or automatic adjuster is utilized, the remote location of the grab member 40 from the vertical rest surface 37 and locator pin 38 of the locator member 36 facilitates the adjustment. As specifically shown in FIG. 4, the grab member 40 is located vertically below the locator pin 38 relatively close to the sideways linear bearing 42y and longitudinal linear bearing 42x. Each linear bearing includes a pair of linear bearing slides 50 extending parallel to its bearing rod. The remote location of the grab member 40 from the vertical rest surface 37 and locator pin 38 of the locator member 36 facilitates the adjustment without binding of these bearing slides 50 and permits adjustment in all three directions by a single movement without the requirement of initial adjusting in one direction and then subsequent adjustment in two other directions as has been required in the prior art.
The adjuster 48 of adjusting station 16 shown in FIG. 1 includes at least one robot 52 whose arm 54 as schematically identified in 54 has an end effector for grabbing the grab member 40 and providing the locator member adjustment as described above. Preferably there are a plurality of the adjusting robots 52 with one robot dedicated to each of two of the adjustable locators 18 shown in FIG. 2 so as to provide a more rapid adjusting cycle.
As illustrated in FIG. 7, each of the locator members 36 on which the locator pins 38 are mounted has a positioning target 56 at a known location with respect to the vertical rest surface and hence also with respect to the locator pin. The positioning target 56 is most preferably constructed with a sharp edge such as provided by a hole to facilitate sensing of its position by a sensor 58 that projects a sensing signal 59. Since the locator pins often have hollow interiors to receive clamp members used for providing part clamping, it is preferably for the positioning target to be remote from the locator pin although in some constructions the positioning target can be on the locator pin. The sensing signal 59 from the sensor 58 senses the location of the positioning target 56 to determine whether the positioning target is positioned within a design tolerance range. A deviation signal is generated by the sensor 58 when the positioning target 56 and thus the vertical rest surface 37 and the locator pin 38 are not located within the design tolerance range. It should be noted that the sensing of the location of the positioning target 56 senses its position in the longitudinal X, sideway Y and vertical Z directions regardless of whether the locator member 36 also has a positioning pin 38 or not.
Adjusting station 16 shown in FIG. 1 includes a control 60 that senses the deviation signal from the sensor 58 and through connections 62 to the adjusting robots 52 provides readjusting of the appropriate locator in response to the deviation signal to provide positioning of the associated locator positioning target within the design tolerance range. The sensing and readjustment can be performed as many times as necessary until the positioning is within the design tolerance range. Control 60 also has a connection 64 as shown in FIGS. 1 and 6 to the linear bearing brakes 46 so as to provide their locked and unlocked conditions as previously described. Furthermore, control 60 has connections 66 to supply and assembly robots 68 of the front, center and rear part stations 20, 22 and 24 previously described.
With reference to FIG. 3, the assembly line has the adjustable locators positioned on the work pallet carriages 34 along their lengths at each lateral side along the longitudinal X direction. On the upper side as illustrated, the adjustable locator 18 farthest to the left and the second from the right have close tolerance spacing of the locator pins 38 and positioning holes in the floor parts 28, 30 and 32 being assembled. Furthermore, the locator 18 farthest to the right and the second locator from the left have close tolerance locator pin and part hole positioning in the sideways Y direction so as prevent rotation of the parts 28, 30 and 32. On the other lateral side of the work pallet carriage 34, the locators 18 only provide vertical part positioning on their vertical rest surfaces since the locator pins 38 of the locators have a greater tolerance spacing with the associated positioning holes in the parts 28, 30 and 32 and thus provide only an initial rough horizontal part positioning without any binding with the positioning provided by the locator pins and part holes on the other lateral side of the work pallet as described above. In fact, these locators 18 that provide only vertical part positioning and do not provide horizontal part positioning do not necessarily have to have positioning pins mounted thereon projecting upwardly from their vertical rest surfaces.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.
Patent Application
20080000068
