Conveyor carrier

REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 60/154,957, filed Sep. 21, 1999.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention generally relates to conveyors and, more particularly, to a conveyor having a carrier adapted to be coupled to a workpiece and drivably engageable by a chain.

2. Discussion

Conveyors are widely used to move workpieces through manufacturing and assembly operations. Examples of such applications include coating or painting systems where the carrier is coupled to the workpiece and engageable with a drive chain. While a variety of conveyor, carrier, and other assemblies are used in the art to convey workpieces through assembly and manufacturing environments, a need exists for carrier assemblies configured to provide greater stability and flexibility in positioning the carrier and the workpieces relative to the chain. The stability of the carrier and workpiece are particularly important when the center of gravity of this assembly increases in distance from the support surface or when the carrier is moved through horizontal or vertical curves.

Many conveyor carriers include wheels that ride on a bearing surface to movably support the carrier and attached workpiece. While a variety of carrier and wheel configurations are used in the art, a need exists for a configuration that permits the carrier to move smoothly through horizontal turns and vertical curves while providing stable support for the workpiece. Another important operational criteria of the conveyor system is that the carriers should be easily re-spaced along the drive chain while the conveyor is in use. The structure providing the additional stability should not impact the spacing flexibility of the overall system.

Finally, in many applications it is desirable to change the orientation of the workpiece relative to the carrier travel path in order to simplify the performance of a production task on the workpiece. While many prior art systems have attempted to address this concern, the solutions have often times been ineffective or overly complex. Accordingly, a need exists for a conveyor system, including a carrier configuration, that provides increased stability without impacting the ease of re-spacing the carriers and that provides for reorientation of the workpiece relative to the carrier.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a stable carrier for moving a workpiece through an assembly or manufacturing operation.

A further object of the present invention is to provide a stabilizer track configuration that provides the improved stability while also allowing the carrier to be removed from engagement and repositioned relative to the drive chain.

Yet another object of the present invention is to provide a rotator assembly for simply and efficiently rotating a workpiece coupled to the carrier to a desired orientation.

A still further object of the present invention is to provide a carrier assembly with each of the above benefits.

In view of the above, the present invention is directed to a conveyor and carrier for use with conveyor wherein the carrier includes a frame having a longitudinal axis, a first pair of load wheels rotatably coupled to the frame, and a first pair of stabilizer wheels positioned laterally outward of the first pair of load wheels and rotatably coupled to the frame. The conveyor includes the carrier, a drive, and a stabilizer track having first and second channels spaced from one another. The first pair of stabilizer wheels are disposable for movement within the channels.

Further scope of applicability of the present invention will become apparent from the following detailed description, claims, and drawings. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given here below, the appended claims, and the accompanying drawings in which:

FIG. 1

is a side elevational view of the conveyor according to the present invention with a segment of the stabilizer track removed for clarity;

FIG. 2

is a front elevational view of the conveyor shown in

FIG. 1

;

FIG. 3

is a top plan view of the conveyor shown in

FIG. 1

illustrating the rotation of the workpiece support assembly as the carrier moves past the rotator;

FIG. 4

is a top plan view of the rotator;

FIG. 5

is a front elevational view of the rotator shown in

FIG. 4

;

FIG. 6

is a side elevational view of an installation gate in the stabilizer track; and

FIG. 7

is a sectional view taken along the line

7

—

7

in FIG.

6

and illustrating that an upper segment of a channel of the stabilizer track is movable between a closed position and an open position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The following detailed description and the appended drawings describe the conveyor of the present invention coupled to a workpiece for moving the workpiece through a coating or paint application. It should be appreciated that the description and illustrations are for exemplary purposes only and that the present invention may be used in a variety of applications and may be modified in a variety of ways not specifically described herein without departing from the scope of the invention as defined by the appended claims.

Turning now to the figures,

FIGS. 1-3

illustrate a conveyor assembly

10

that includes a track system

12

and a carrier

14

adapted to be coupled to a workpiece

16

. The track system

12

includes a drive track

18

and a chain

20

disposed for movement within the drive track. The chain

20

includes pusher dogs

22

extending above the drive track

18

to engage and drive the carrier

14

as hereinafter described. While the chain is described and illustrated herein as an endless Unibilt® chain such as that manufactured by Jervis B. Webb, the assignee of the present application those skilled in the art will appreciate that a variety of drive chains, belts, and the like may be used without departing from the scope of the invention. The conveyor assembly is illustrated as an inverted application where the workpiece is supported above the drive chain and, as is known in the art, the conveyor includes a drive assembly for moving the chain and a take-up for maintaining the proper chain tension.

The conveyor commonly includes a plurality of carriers each connected to the chain at selected pusher dogs and therefore at predetermined intervals. A single pusher dog, carrier, and workpiece is illustrated in FIG.

1

. The carrier

14

includes a carrier frame

24

coupled for movement with the pusher dog

22

and a support assembly

26

fixed for movement with the frame and supporting the workpiece

16

. As is best illustrated in FIGS.

1

and

2

, the carrier

14

is centered above the drive chain

20

and includes a guide roller

28

rotatably coupled to the frame and positioned between guide flanges

30

to restrict movement of the carrier perpendicular to its longitudinal axis

32

(FIG.

3

). A drive bracket

34

is fixed to the frame

24

and includes a hole

36

that is configured to accommodate the pusher dog

22

.

As noted above, the carrier of the present invention provides a stable structure for supporting the workpiece for movement with the chain. The carrier frame

24

includes front and rear cross bars

42

and

44

, respectively, interconnected by a longitudinal load bar

46

. As is most clearly illustrated with respect to the front cross bar

42

shown in

FIG. 2

, the front and rear cross bars each preferably include a horizontal plate

52

that terminates at its lateral ends in downwardly depending legs

54

. The carrier also includes front and rear pans of inner load wheels

38

and

40

and front and rear pairs of outer stabilizer wheels

48

and

50

each rotatably coupled to front and rear frame cross bars

42

and

44

, respectively. More particularly, the stabilizer wheels

48

and

50

are coupled to the legs

54

for rotation about a fixed pin axis

55

while the pairs of load wheels

38

and

40

are rotatably coupled to the horizontal plate

52

by a caster mounting assembly

56

that permits the wheels to rotate about axes

57

and

59

.

When it is desirable to have the stabilizer wheels support the frame, such as in straight sections and vertical curves, a stabilizer track

62

is provided to receive the wheels

48

and

50

. The stabilizer track

62

includes first and second channels

64

and

66

(

FIGS. 2 and 3

) which are spaced from one another and parallel to the longitudinal axis

32

of the carrier. The channels

64

and

66

are configured to vertically restrain the carrier during operation while the operative engagement of the guide roller

28

with the guide flanges

30

provides horizontal restraint. The front and rear pairs of load wheels

38

and

40

each define a load plane

58

(

FIG. 2

) and the front and rear pairs of stabilizer wheels

48

and

50

each define a stabilizer plane indicated by reference numeral

60

that is positioned vertically above the load plane

58

. Due to the preferred vertical separation between the load plane

58

and the stabilizer plane

60

, the load wheels

38

are raised out of rolling engagement with the carrier support surface when the stabilizer wheels

48

rollingly engage the track

62

(FIG.

2

). Accordingly, the carrier configuration permits the load wheels

38

to support the carrier and workpiece for movement with the chain in areas where a stabilizer track is absent, such as where the carrier is traversing a horizontal curve. Conversely, in areas where additional stability is desirable or the flexibility of the caster assembly is unnecessary, the stabilizer track

62

may be provided such that the stabilizer wheels

48

rollingly support the carrier within the channels

64

and

66

. Based on this description, as well as the appended drawings and claims, those skilled in the art will appreciate that the conveyor of the present invention may include sections with and without the stabilizer track as needed to capitalize on the addition degree of freedom provided by the caster mounted load wheels and the stability provided by the stabilizer wheels. As a result, the loadings on the load wheels

38

and

40

can be eliminated in straight sections and vertical curves thereby decreasing the wear on the load wheels and the caster mounting assembly

56

.

In certain instances, it may be desirable to re-space the carriers within an area where the stabilizer wheels are disposed within a stabilizer track

62

. Accordingly, each of the channels

64

and

66

are configured to include an installation gate

67

wherein the carrier can be vertically displaced relative to the drive chain to permit the carrier to be removed from engagement with the chain and easily repositioned to redefine the carrier intervals. More particularly, each channel includes an upper segment

68

, a lower segment

70

, and a hinge

72

pivotably intercoupling the upper and lower segments to permit the upper segment to be moved between a closed position and an open position (FIGS.

6

and

7

). Locks

74

are preferably included with the channels to maintain the upper segments in their closed positions during operation of the conveyor. The locks can be of any suitable configuration and preferably include a pin that is slidable between locked and unlocked positions.

With the above description in mind, those skilled in the art should appreciate that the present invention provides a stable carrier configuration that is movable in driving engagement with the drive chain to permit movement of the workpiece by the drive chain. The invention also permits the respective carriers to be removed from operative engagement with the drive chain by moving the upper segments from their closed position to their open position and vertically displacing the carrier relative to the drive chain to remove the pusher dog

22

from the hole

36

.

As noted above, the present invention also includes a rotator that allows for workpiece rotation while the carrier is in motion. The rotator is selectively engageable with the carrier to provide a predetermined magnitude of rotation as the carrier passes the rotator. The rotator may be maintained in a retracted position if no workpiece rotation is desired.

As is best illustrated in

FIGS. 2-5

, the conveyor assembly

10

includes a rotator assembly

80

having a slide

82

movable in the direction of arrow

83

between an engaging position and a retracted position through movement of a handle

84

. A plurality of engagement rollers

86

are coupled to the forward segment of the slide and aligned parallel to the carrier travel path

87

. The support assembly

26

of the carrier

14

includes a rotatable upper shaft

88

and a rotator plate

90

fixed for rotation with the shaft

88

. The plate

90

has a plurality of fingers

92

extending radially from a hub

94

such that when the slide

82

is in its engaging position the engagement rollers

86

are positioned in the path of the fingers

92

. As a result, as the shaft

88

moves past the slide

82

, the rollers

86

engage the fingers

92

causing the plate

90

and the shaft

88

to rotate in the direction indicated by arrow

96

. The workpiece

16

is coupled to rotate with the shaft

88

via cross member

98

and support legs

100

. Accordingly, the workpiece

16

rotates with the cross member

98

(

FIG. 3

) as the carrier

14

movies past the rotator assembly

80

. It should be appreciated that the number and/or spacing of the engagement rollers or fingers may be varied to cause the desired degree of rotation of the workpiece as the carrier passes the slide. Moreover, if no rotation is needed, the slide may be maintained in its retracted position where the rollers

86

are spaced a sufficient distance from the shaft

88

so as not to engage the fingers

92

. Additionally, it should be appreciated that while the slide is shown as being manually manipulatable by the handle

84

, numerous configurations generally known in the art may be incorporated into the invention to permit automatic controlled movement of the slide between its engaging and retracted positions.

The foregoing discussion discloses and describes an exemplary embodiment of the present invention which includes a carrier configuration that provides increased carrier stability throughout the carrier travel path or in areas where increased stability is needed, permits the carriers to be removed from operative engagement with the drive chain when the stabilizer wheels are rollingly supported by tracks, and provides a simplified and effective rotator assembly for changing the orientation of the workpiece relative to the carrier. Notwithstanding the exemplary embodiments described above, one skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims that various changes, modifications and variations can be made therein without departing from the true spirit and fair scope of the invention as defined by the following claims.