Carrier locking system for pendulum conveyor

BACKGROUND OF THE INVENTION

This invention relates to improvements in overhead horizontal pendulum conveyor systems and, in particular, to a pendulum arm therefor which cooperates with a receiver on a carrier frame to lift and transport a vehicle part or other object under assembly along an inclined as well as a horizontal path, such as through surface treatment tanks, where the carrier and part may become buoyant and tend to separate from the pendulum arms.

In the assembly line manufacture of motor vehicles such as automobiles and trucks, it is known to provide an overhead horizontal pendulum conveyor system from which pendulum arms depend, typically in groups of four for supporting the four corners of a rectangular skid frame or carrier. These conventional pendulums hang vertically from the conveyor and have hooks on their lower ends for engaging laterally outwardly projecting arms (connecting arms) extending from the supporting frame of the skid or carrier upon which an object is transported. The connecting arms must extend beyond the maximum width of the carried object to provide clearance for the pendulums. Thus the total width of the carrier must be significantly greater than the width of the object and the supporting frame.

Furthermore, when the carrier and its associated object are disengaged from the pendulum conveyor and transported by other conveyor means, an excessive lateral space is consumed by the width of the carrier frame and its connecting arms, thereby increasing the area that must be clear of obstructions. Additionally, ovens for drying components, for example, must be sized to accommodate the width of the carrier, not just the object. Such carriers also require a large amount of storage space, may be difficult or cumbersome to handle, and the protruding connecting arms may be prone to damage. Once such carrier is shown in U.S. Pat. No. 4,831,962 to Gros.

SUMMARY OF THE INVENTION

It is, therefore, the primary object of the present invention to provide a pendulum conveyor in which the width of the carrier associated therewith is minimized.

A corollary to the foregoing object is to provide a pendulum conveyor and associated carrier which are positively interlocked during upward and downward courses.

Another important object of the present invention is to provide an apparatus as aforesaid which automatically locks the pendulum arms to the carrier when the carrier is not substantially horizontal.

Still another important object of the present invention is to provide an apparatus as aforesaid that prevents the carrier and part from becoming separated from the pendulum arms when lowered into a tank of liquid through the use of a receiver on the carrier which is positively interlocked with a mating coupler on a corresponding pendulum arm.

Yet another important object of the present invention is to provide an apparatus as aforesaid which has a carrier which is not prone to damage due to protruding members and minimizes maintenance.

A further important object of the present invention is to provide an apparatus as aforesaid which minimizes the space required for storage.

Another important object of the present invention is to provide an apparatus as aforesaid which accommodates smaller assembly line equipment such as ovens and processing tanks.

Still another important object of the present invention is to provide an apparatus as aforesaid having pendulum arms which extend generally horizontally inwardly to the associated receivers to engage and lock the carrier to the arms.

These and other objects of the invention are achieved by providing a generally L-shaped pendulum arm which depends from an overhead horizontal pendulum conveyor and provides a coupler at the free end of an inwardly extending, horizontal portion of the arm. The coupler is designed to engage a receiver on an associated carrier and automatically interlock when the carrier rotates and assumes an inclined orientation during a downward or upward course of the conveyor. In vehicle part process treatment applications, this eliminates the possibility of the carrier and vehicle part floating off of the pendulum arms when descending into a treatment tank. The carriers may be conveniently handled and stored during nonuse, as the receivers do not add any significant width to the carrier frames.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, an embodiment of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is plan view of a prior art carrier showing vehicle envelopes and connecting arms extending from the carrier.

FIG. 2

is a plan view of a carrier and receivers of the present invention.

FIG. 3

is a fragmentary, rear elevational view of a pendulum suspended from a conveyor and a fragmentary, rear elevational view of a carrier frame and attached receiver.

FIG. 4

is a fragmentary, side elevational view of a horizontal pendulum conveyor with the pendulums of the present invention partially cut away to show the coupler engaged in the receivers, and supporting a carrier and a vehicle frame illustrated in phantom lines thereon.

FIG. 5

is a rear elevational view of the horizontal pendulum conveyor system of the present invention showing a pair of pendulums engaged in the respective receivers attached to a carrier frame supporting a vehicle and parts illustrated in phantom lines.

FIG. 6

is a fragmentary, side elevational view of a portion of a horizontal pendulum conveyor showing a vehicle illustrated in phantom lines supported by a carrier frame being lifted from a conveyor by the pendulum arms.

FIG. 7

is a fragmentary, rear elevational view along the direction of travel of the conveyor and of the right receiver illustrated in FIG.

6

.

FIG. 8

is a fragmentary, rear elevational view along the direction of travel of the conveyor and of the left receiver illustrated in FIG.

6

.

FIG. 9

is a fragmentary, diagrammatic plan view of the horizontal pendulum conveyor system showing a carrier being lifted from a first conveyor, transferred by the pendulum arms and placed on a second conveyor.

FIG. 10

is a detail view showing a receiver in side elevation.

FIG. 11

is a right end elevational view of the receiver shown in FIG.

10

.

FIG. 12

is a vertical sectional view taken along line

12

—

12

of

FIG. 3

showing the coupler on the same scale as FIG.

10

.

FIG. 13

is a fragmentary, end elevational view of the horizontal arm and coupler.

FIG. 14

is a perspective view of the coupler and receiver prior to engagement.

FIG. 15

is a vertical sectional view taken along line

15

—

15

of

FIG. 8

showing the coupler engaged in the receiver, on the same scale as FIG.

10

.

FIG. 16

is a sectional view taken along line

16

—

16

of

FIG. 15

showing the coupler engaged in the receiver.

FIG. 17

is a vertical sectional view similar to

FIG. 15

but showing that the coupler and receiver will not separate provided the carrier is inclined at 8° or more.

FIG. 18

is a vertical sectional view showing the maximum rotational angle that the receiver and coupler can accommodate.

FIG. 19

is an illustration of a carrier and vehicle part descending into a treatment tank.

DETAILED DESCRIPTION

Referring initially to

FIGS. 1 and 2

, a prior art carrier or skid

500

is illustrated in FIG.

1

. Carrier

500

has connecting arms

502

extending laterally from the rectangular skid frame beyond the side projections of a large vehicle part or object illustrated by broken lines

504

, and well beyond the side projections a smaller object or vehicle part

506

. In comparison, carrier

20

of the present invention illustrated in

FIG. 2

includes receivers

22

at each corner of carrier

20

and cross members

24

, none of which extend beyond the side projections of vehicle parts

504

or

506

.

Referring to

FIGS. 3-5

, an overhead horizontal pendulum conveyor system referenced generally by

26

has a pair of parallel, horizontally spaced-apart monorail I-beam tracks

28

which support and guide a number of trolleys

30

. A drive chain

32

for each track

28

interconnects trolleys

30

below the respective track. Drive chains

32

power the trolleys

30

to move conveyor

26

in the direction indicated by the arrow in

FIG. 4

(from right to left).

Each of four generally L-shaped pendulums

34

pivotally depends from the lower portion of a corresponding C-hook

36

which is bolted to an index head

38

pivotally depending from an associated trolley

30

. Index heads

38

may pivot in line with the direction of travel of the conveyor

26

, while pendulums

34

may pivot transversely to the direction of travel of conveyor

26

. A counterweight

40

is attached to the upper end of each pendulum

34

to offset the weight of horizontal arm

42

of pendulum

34

and keep horizontal arm

42

in a generally horizontal position. The pendulums

34

are preferably constructed of steel pipe to support a heavy object or vehicle such as a sport utility vehicle.

Each pendulum

34

and cooperating parts are identical in construction. A coupler

44

, attached to the free end of horizontal arm

42

, is designed to engage receiver

22

attached to carrier or skid

20

to enable pendulum

34

to lift skid

20

and securely carry a vehicle

45

and parts

46

. Considering coupler

44

and receiver

22

in more detail (FIGS.

10

-

14

), receiver

22

is generally an open rectangularly shaped box having spaced-apart generally parallel outer

48

and inner

50

walls. End walls

52

and

54

present the ends of receiver

22

and are secured to carrier

20

. A receiver

22

is preferably attached at each corner of carrier

20

(

FIG. 2

) to provide lifting points to evenly distribute the weight of a transported object. Outer

48

and inner

50

walls present generally arch-shaped apertures

56

and

58

respectively which are in axial alignment with receiver axis

59

. Receiver axis

59

is generally perpendicular to outer

48

and inner

50

walls of receiver

22

. Outer

48

and inner

50

walls also present aligned arcuate slots

60

and

62

which are in communication with apertures

56

and

58

respectively. Arch or saddle member

64

extends between walls

48

and

50

and is secured along the inside edges of arches

56

and

58

. The inside curvature of saddle member

64

generally conforms to the outside curvature of horizontal arm

42

.

Coupler

44

generally comprises of a pair of spaced-apart inverted generally triangular plates

66

and

68

each having an arcuate cut-out

70

and

72

for receiving horizontal arm

42

. Coupler

44

is welded or otherwise secured to the free end of arm

42

. Coupler plates

66

and

68

each have apertures which are in axial alignment with a locking pin axis

73

which is generally parallel to horizontal arm axis

43

and through which opposed locking pins

74

and

76

extend inwardly respectively to a channel

78

formed between plates

66

and

68

.

Referring to

FIGS. 15 and 16

, when coupler

44

is seated in receiver

22

, receiver axis

59

and horizontal arm axis

43

are in a coaxial relationship, and saddle

64

rides on the surface of horizontal arm

42

within channel

78

. The radial distance between the center line

61

of slot

60

and receiver axis

59

is approximately equal to the radial distance from horizontal arm axis

43

and locking pin axis

73

. Thus, locking pins

74

and

76

are approximately centered within arcuate slots

60

and

62

. As illustrated in

FIG. 15

, coupler

44

and receiver

22

are in an unlocked position.

Referring to

FIGS. 6-8

, as carrier

20

supporting vehicle part

45

travels in the direction indicated in

FIG. 6

(from left to right) along inverted power and free conveyor or skid conveyor

80

, pendulum conveyor system

26

moves in synchronism so that pendulums

34

are aligned with the receivers

22

. Horizontal pendulum arms

42

on each side of skid

20

approach skid

20

approximately seven inches below the right receiver

22

in FIG.

6

and the receivers

22

shown in

FIG. 7

looking in the direction of travel of conveyor

26

. Monorail

28

provides a nine inch rise thus lifting skid

20

two inches off a conveyor represented at

80

(shown in

FIG. 6

) and fully engaging coupler

44

and the left receiver

22

of

FIG. 6

(see

FIG. 8

looking in the direction of travel of conveyor

26

). The outwardly tapered channels of arcuate slots

60

and

62

assist in guiding the coupler into the receiver as the skid

20

is lifted from conveyor

80

(see

FIGS. 6

,

14

,

15

and

17

).

Referring to

FIGS. 6

,

9

and

15

-

19

, carrier

20

transporting vehicle part

45

is lifted from conveyor

80

and carried to process dip tank

82

. Carrier

20

may pivot up to approximately 45 degrees as it descends into and ascends from tank

82

. Likewise, saddle

64

in each receiver

22

pivots on the connecting horizontal arm

42

(FIG.

18

). As vehicle part

45

descends into tank

82

, air becomes trapped in the vehicle part

45

. Because of this trapped air, vehicle part

45

and carrier

20

may become buoyant and float in the processing liquid

84

, becoming separated from pendulums

34

and eventually sink to the bottom of processing tank

82

. Locking pins

74

and

76

interlock each receiver

22

and coupler

44

to prevent vehicle

45

and carrier

20

from separating from horizontal pendulum arm

42

of pendulum

34

.

After vehicle

45

is treated in processing tank

82

, carrier

20

is lowered onto inverted power and free conveyor or skid conveyor

86

and automatically released from pendulums

34

. As pendulums

34

reach the end of the overhead conveyor

26

, having released carrier

20

on conveyor

86

, the empty pendulums

34

continue around conveyor

26

as indicated by the direction arrows in FIG.

9

. Index heads

38

rotate 90 degrees so that horizontal pendulum arms

42

are parallel with the direction of travel to reduce the area required for conveyor system

26

. As the pendulums

34

reach the beginning of the conveyor system

26

, each index head

38

rotates back 90 degrees so that horizontal pendulum arm

42

is once again generally transverse to the direction of travel of carriers

20

on conveyor system

26

in order to pick-up another carrier

20

.

From the forgoing description it should be appreciated that the width of carrier

20

is substantially less than prior art carriers and thus inherently requires less storage space. Additionally, because the receivers

22

do not extend significantly from the sides of carrier

20

, receivers

22

are not prone to encountering normal obstructions in an assembly line environment and thereby become damaged. Horizontal arms

42

extend to engage carrier

20

only when necessary to transport carrier

20

and are otherwise parallel to the conveyor system

26

direction of travel to eliminate an unnecessary use of space around the conveyor

26

when pendulums

34

are returning to the beginning of the conveyor line.

It is to be understood that while a certain now preferred form of this invention has been illustrated and described, it is not limited thereto except insofar as such limitations are included in the following claims and allowable equivalents thereof.