Stacking machine for part trays

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to devices for controlling delivery of workpieces and/or workpiece containers of substantial size in manufacturing or assembly operations and, more particularly, to an improved material storage and delivery structure and system for storing, delivering, positioning and removing both full and empty workpiece containers to and from assembly or production line workstations as desired.

As is well known, assembly or production line facilities require the delivery and temporary storage of large volumes of production parts at or near assembly or production line workstations to support worker line operations on a continuous mass production basis. Automotive production line or assembly line operations in particular require the delivery of large numbers of parts of substantial size for assembly to automotive or truck vehicles or subsystems thereof, on a continuous basis. For example, engines, body panel parts, air conditioning assemblies, fuel tanks and brake assemblies are typically stored, moved and delivered to line workstations in stackable trays or pallets, which have a substantial volume and mass.

Due to the fact that mass production operations require the continuous delivery of a large number of such parts during any particular work shift, typical assembly line operations require movement, positioning and temporary storage of large numbers of such stackable trays at the production facility. Substantial floor space is thus often needed for movement and repositioning of both full and empty trays to facilitate delivery of full trays to the production line and removal of empty trays when the production parts contained in each tray has been fully depleted. Typically, empty trays are moved by the line operators into a position out of the way. Due to the size and weight of these empty trays, significant ergonomic problems have arisen.

It is, therefore, desirable to provide a production part container storage and delivery system which facilitates the delivery of fresh trays of parts to a production line work station as needed. It is also desirable to provide such a system, which enables empty trays to be similarly removed from assembly line workstations without operator or continuous service vehicle assistance. It is further desirable to provide such a system which stores in positions full and empty production part trays as desired and which facilitates the storage, delivery, positioning and removal of a sufficient number of such trays to obviate the need for supplemental vehicle intervention over the entire work shift. It is also desirable to provide a system which enables production workers to index the height of the trays at the workstation as needed to improve ergonomic conditions.

The present invention is intended to satisfy the above desirable features through the provision of a new and improved container storage and delivery structure and system which is designed in structural modules operative to define a base portion having an input and output portion, a shuttle lift for lifting and positioning empty trays into a discharge portion, and a shuttle or conveyor for conveying the empty trays into the discharge portion.

In one embodiment of the invention, the output portion has a rotatable table and a lift. These components allow the operator to position the components stored in the trays in the most ergonomically efficient position. The system further has a controller for controlling the operation of the conveyor and the lift, with the system shuttling empty trays and stacking them properly in the discharge position.

The above and other features of the invention will become apparent in the reading of the detailed description of the preferred embodiments, which makes reference to the following sets of drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a right side view of a container storage and delivery system in accordance with one embodiment of the present invention;

FIGS. 2-7

are right side views of the system of

FIG. 1

illustrating various stages in its mode of operation;

FIG. 8

is a front view of the system of

FIG. 1

;

FIG. 9

is a top view of the output portion of the system;

FIG. 10

is a sectional view of the lift mechanism of the system;

FIG. 11

is a rear view of the system; and

FIG. 12

is schematic diagram of the system controller.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now specifically to the drawings, a container storage and delivery structure and system in accordance with one embodiment of the present invention is indicated generally in FIG.

1

. The system has a base portion

10

having an input portion

14

, output portion

18

and conveyor

54

. The shuttle

74

has a support member

62

and a shuttle lift

58

for transporting empty stackable tray containers to a discharge portion

94

. The stack of trays

5

is placed into the input portion

14

on the conveyor

54

by a lift truck

2

. The structure is constructed of pairs of vertical and horizontal square tubing members

12

,

13

that function as the support member

62

. The discharge portion

94

is constructed of four parallel square tubing members

12

and at least one pair of horizontal square tubing members

13

supporting a platform

15

.

Shown in

FIG. 2

is the stack of trays

5

being placed on the conveyor

54

. Conveyor

54

, which is driven by a conveyor drive

55

, functions to transport the stack of trays

5

from the input portion to the output portion

18

. The conveyor

54

can be a standard shuttle type, chain driven or roller type. The shuttle

74

is shown in a lowered position, ready to transport an empty tray

7

from the stack to the discharge portion

94

.

FIG. 3

shows the stack of trays

5

after they have been transported to the output portion

18

by conveyor

54

. Further shown is the shuttle lift

58

, which is used to raise the shuttle

74

from its lower position to its fully raised position. Also shown in the output portion

18

is a table lift

26

for automatically lifting the trays

5

to a number of pre-determined positions. The shuttle

74

has a plurality of grippers

86

for lifting an empty tray

7

and placing it in the discharge portion

94

. The grippers

86

have actuatable pins which engage either holes in the empty trays

7

or under engaging portions

16

of the trays

7

.

FIG. 4

shows the shuttle member

74

lifting an empty tray

7

to a raised position. The table lift

26

raises the stack trays

5

so the top layer is at a proper predetermined level A. This allows proper access to the components stored in the trays. Shown on shuttle

74

is a sensor

90

a

which allows the shuttle to determine its position with respect to the trays.

FIG. 5

shows the empty tray

7

being conveyed by the shuttle conveyor

78

over the discharge portion

94

. Found on the shuttle member

74

is a safety lock

92

, which prevents the accidental lowering of the shuttle member

74

in the event of equipment or power failure. Shown in

FIG. 6

is the shuttle

74

being lowered to a point where it is possible to safely release the empty tray

7

by actuating the grippers

86

and allow the empty tray

7

to fall. Sensor

90

a

is used to determine when the shuttle

74

is in a proper position. As can be seen in

FIG. 7

, when the empty tray

7

has been dropped, the shuttle

74

is again raised to its uppermost position and the shuttle conveyor

78

is now allowed to move the grippers

86

back over the stack of trays

5

. Upon instruction by the operator, the shuttle will again lower to pick up an empty tray and deposit it on top of the stackable empty tray

7

which has been placed in the discharge position

94

.

FIG. 8

shows a front view of the container storage system holding a stack of trays

5

in the output portion

18

of the base

10

. Shown is a rotatable table

22

and a table lift

26

for raising the stack of trays

5

once an empty tray has been removed from the top and placed into the discharge portion

94

.

FIG. 9

is the top view of the output portion of the current embodiment. Shown is the rotating table

22

and the conveyor

54

. Also shown is the table lift

26

in the form of a screw drive lift. It should be noted, however, that this lift can be a scissor lift, a chain lift, a pneumatic lift or a hydraulic lift. The table lift

26

is controlled by a controller

100

found in the control panel

56

which increases the height of the trays

5

every time the top tray has been removed and placed into the discharge portion

94

. The desired height is readily changeable by the operator. Additionally shown is a supplemental sensor

90

b

which is used by the system to determine when all of the stackable trays have been removed from the output portion and to sense when a full stack of trays

5

has been transferred to the output portion.

FIG. 10

shows an alternate embodiment. The stack of trays

5

often has a cover

8

for protecting the top layer of components from the elements. This embodiment shows an alternate storage location

70

for holding the cover

8

while the empty trays

7

are being removed from the stack of trays

5

. When the last of the empty trays

7

is placed in the discharge portion

94

, the shuttle will remove the cover

8

from its storage location

70

and place it on top of the stack of trays

5

.

FIG. 11

shows a front view of the alternate embodiment having the storage location

70

for storing the top cover

8

. It should be noted that the upper member for storing the cover

8

does not interfere with the normal functioning of the shuttle

74

.

The system has a controller

100

stored in control panel

56

. As diagrammatically shown in

FIG. 12

, the controller

100

controls the conveyor drive

55

, the shuttle lift

58

, the shuttle conveyor

78

and the grippers

86

. Inputs to the controller

100

come from a plurality of sensors

90

a-c

throughout the system as well as an operator input

92

from control panel

56

. In operation, the controller receives input from sensor

90

c

located in the input portion

14

when a stack of trays has been inserted. If the controller

100

determines there are no empty trays

7

in the output portion

18

or the discharge portion

94

, the controller

100

directs the conveyor

54

to transport the stack of trays

5

to the output portion. The stack tray

5

is then placed on the rotatable table

22

in the output portion

18

and the conveyor

54

is returned to the input portion

14

.

A signal is then provided to the table lift

26

to raise the height of the stack tray

5

to a pre-determined level A. After the operator has removed the components in the tray, a push button

92

is activated which brings the shuttle

74

into position around the empty tray

7

. The height of the shuttle

74

is controlled by the controller

100

in response to inputs from sensors

90

a-c

on the shuttle. The grippers

86

then engage the sides of the empty trays

7

.

The shuttle

74

is then raised by the controller

100

to a pre-determined height. Upon reaching this height, the shuttle conveyor

78

transports the empty tray

7

over the discharge portion

94

. The shuttle

74

is then lowered by the controller

100

an amount based on input from the shuttle sensor

90

a

. The sensor

90

a

determines the height of the stack of trays

5

in the discharge portion

94

. Upon reaching the proper height, the controller provides a signal to the grippers

86

to release the tray

7

, which drops onto the discharge region

94

.

After placing the empty tray

7

in the discharge region

94

, the shuttle

74

is again raised to a pre-determined height and the shuttle conveyor

78

is moved over the output portion

18

. Upon receiving instruction from the operator, the shuttle

78

will drop and retrieve the next available empty tray

7

.

Many changes and modifications in the above described embodiment of the invention can, of course, can be carried out without departing from the scope thereof. Accordingly, that scope is intended to be limited only by the scope of the appended claims.