RACK LOADING AND UNLOADING APPARATUS

• US 3,682,331 A
• Filed: 09/08/1970
• Issued: 08/08/1972
• Est. Priority Date: 09/08/1970
• Status: Expired due to Term

• Current Assignee: Robert C. Burlingame
• Original Assignee: Robert Theodore Fetherston
• Inventors: Fetherston, Robert Theodore
• Primary Examiner(s): Arnold, P.
• Application Number:
  US05/070,174
• Time in Patent Office: 700 Days
• Field of Search: 198/2T 214/16.4R,16.4A,6G
• US Class Current: 414/331.13
• CPC Class Codes: B65G 49/085 for loading or unloading racks or similar frames; loading racks therefor

Abstract

The apparatus provides for loading heavy articles such as mold boards which support roof tiles onto a rack while simultaneously unloading mold boards from a different section of a rack. The loading-unloading arrangement includes an infeed conveyor and a first loading arm, and an unloading arm and outfeed conveyor. The infeed conveyor is supported by the loading arm and the outfeed conveyor is supported by the unloading arm. A pulley and chain arrangement interconnects the loading and unloading arms so that the weight of the infeed conveyor and loading arm and the articles thereon counterbalances the weight of the outfeed conveyor and unloading arm and the articles thereon. Hence, the loading and unloading systems are effectively counterbalanced by each other even when the several conveyors transport mold boards supporting heavy tiles.

Claims

1. A conveyor system to load articles on a rack of the type having a row of spaced apart article supporting ledges comprising, in combination a horizontal arm conveyor having a width less than the distance between ledges of said rack;

first support means for said conveyor arm;

means mounting said conveyor arm on said first support means for vertical movement while maintaining said arm horizontal;

means mounting said first support means for movement to a first position on which said arm extends substantially into and between the article supporting ledges of a rack, and to a second position in which said arm is retracted and spaced from the rack;

a conveyor pivotally supported at one end by said first support means, said one end being vertically movable with said horizontal arm and being adjacent one end of said arm, whereby articles conveyed by said conveyor are transferred to said arm;

means continuously driving said conveyor during the loading of a row of a rack;

means continuously driving said arm conveyor during the loading of a row of a rack;

means to index said arm conveyor vertically to plural positions in each of which an article supporting surface of the arm conveyor is slightly above the article supporting ledges of the rack, whereby an article on said arm is deposited on said ledges by downward indexing movement of the arm; and

means responsive to the movement of at least one article to a predetermined position on said arm conveyor to automatically activate said index means to move said arm conveyor vertically a distance equal to the vertical distance between ledges of the rack.

2. A conveyor system according to claim 1 wherein a rack conveyor extends transversely in front of said conveyor arm, said rack conveyor being operable to transport a rack in a direction transversely of said arm;

and means to operate said rack conveyor to automatically position a row of a rack on the conveyor in alignment with said arm.

3. A conveyor system according to claim 1 wherein said system further includes means responsive to loading the row of a rack to automatically actuate said mounting means for said arm conveyor to move same to second position.

4. A conveyor system according to claim 1 wherein said system further includes a rack conveyor to precisely align a row of a rack with said conveyor arm;

and means to actuate said conveyor to align an immediately adjacent row of a rack with said arm in response to movement of said mounting means for said first support means to said second position.

5. A conveyor system according to claim 1 wherein said means mounting said first support means for movement is an upright frame;

and said first support means includes a cradle mounted on said frame for vertical movement to a plurality of spaced apart horizontal positions.

6. A conveyor system according to claim 1 wherein said system further includes means to automatically return said means mounting said conveyor arm on said first support means to a start position in which said arm conveyor is at the top of a row of a rack to be loaded;

said rack is mounted on a conveyor including means to move the rack in a direction transversely of said arm conveyor;

aNd means to move said means mounting said first support means to said first position in response to movement of said arm to said start position, and alignment of a row of a rack on said rack conveyor with said arm;

whereby, said arm conveyor is moved to said first position only if it is in a proper start position and is aligned with a row of a rack on the rack conveyor.

7. A conveyor system according to claim 1 wherein a rack conveyor extending transversely of said arm automatically moves a rack thereon to a position in which a next row of the rack is aligned with said arm, in response to movement of said means mounting said first support means to said second position;

means responsive to movement of said means mounting said first support means to said second position is effective to actuate said first support means to move to a position in which said arm conveyor is in a start position, and actuate said rack conveyor to move a rack to a position in which a next adjacent row of the rack is in alignment with said arm conveyor; and

means responsive to alignment of the next adjacent row of a rack with said arm and movement of said arm to a start position to automatically actuate said mounting means to move said support means to said first position.

8. Apparatus for loading pallets on a rack comprising, in combination an infeed conveyor system including an infeed conveyor, and a loading arm conveyor;

a frame;

carriage means mounting said loading arm conveyor on said frame for vertical movement while maintaining said arm horizontal;

means pivotally connecting said infeed conveyor to said carriage at one end for pivotal movement relative to said conveyor arm;

a rack conveyor extending transversely of said arm and in front of said frame;

a rack on said rack conveyor, said rack including a plurality of side by side rows, each including a plurality of pairs of shelf ledges to support a plurality of pallets, said ledges being spaced apart to permit vertical movement of said arm therebetween;

means to index said arm vertically a distance equal to the distance between adjacent shelves of a row;

means mounting said frame on a base for fore and aft movement to extend said arm into a row of a rack and to retract said arm from a row;

means responsive to indexing said arm to a position below the bottom shelf of a row to move said frame to the aft position;

means responsive to movement of said frame to the aft position to actuate said rack conveyor to move a new row of a rack into alignment with said arm;

means responsive to movement of said frame to the aft position to move said arm to an upper position on said frame;

means responsive to moving a new row into alignment with said arm to move said frame to a forward position; and

means responsive to a predetermined number of pallets on said arm to index said arm downwardly.

9. Apparatus according to claim 8 which further includes means upstream of said loading arm conveyor to arrange articles in groups of a predetermined number for loading on said rack;

said groups having a total length approximately equal to the length of a pair of ledges of the rack.

10. Apparatus according to claim 8 wherein said means to move a new row of a rack into alignment with said arm includes a light source, and light responsive means, responsive to a change in illumination resulting from movement of said rack, to automatically de-actuate said conveyor in response to movement of a new row of a rack into alignment with said arm.

11. Apparatus according to claim 8 wherein said conveyor conveyor further includes means to precisely align a row of a rack both transversely and longitudinally of said loading arm conveyor.

12. A conveyor system to selectively load a rack, unload a rack, or simultaneously load one row of a rack while unloading another row of a rack, said rack being of tHe type having at least one row of horizontally aligned pairs of article supporting ledges with the pairs of ledges spaced apart equally vertically and ledges of each pair spaced apart horizontally to receive an arm conveyor of the system therebetween comprising, in combination a first horizontal conveyor arm;

a second horizontal conveyor arm;

a support;

means mounting said conveyor arms on said support in horizontally spaced relation for vertical movement while maintaining the article supporting surfaces of the arms horizontal;

means interconnecting said arms for simultaneous movements, one up and the other down, said means supporting said arms in counterbalanced relation to each other; and

means to simultaneously index said arms vertically in step by step fashion.

13. A conveyor system according to claim 12 wherein said means interconnecting said arms for simultaneous movement includes a chain, first and second sprocket means supporting said chain at locations generally above said respective first and second arms, and means imparting indexing motion to at least one of said sprockets to simultaneously move said first arm down and said second arm up the same distance.

14. A conveyor system according to claim 12 wherein a rack conveyor extends transversely of said first and second arms, said rack conveyor including means to simultaneously align a row of a first rack with said first arm and row of a second rack with said second arm;

and means associated with said rack conveyor to actuate same to automatically move a second row of one rack to a position in alignment with said first conveyor arm and to simultaneously move a second row of another rack into alignment with said second conveyor arm. 15, A conveyor system according to claim 12 wherein said support is mounted on a base for movement in a direction longitudinally of said arms to a first position in which each of said arms is completely withdrawn from a row of a rack, and to a second position in which each of said arms is in a forward position and extends through a row of a rack.

16. A conveyor system according to claim 12 wherein said means to simultaneously index said arms vertically includes a pneumatic cylinder having a piston rod, means maintaining constant pressure on the piston of said pneumatic cylinder, a hydraulic cylinder having a piston rod, a liquid filling said hydraulic cylinder, and a valve to release said liquid, means connecting said piston rods together for simultaneous movement, an index device connected to one of said piston rods for movement therewith, means responsive to actuation of said index device to open a valve of said hydraulic cylinder to release the piston of the hydraulic cylinder for movement with the piston of the pneumatic cylinder, and means responsive to a predetermined movement of said index device to close said valve;

whereby, constant pressure on said air cylinder causes movement of the piston of the air cylinder and hydraulic cylinder simultaneously in response to opening said valve.

17. A conveyor system according to claim 12 wherein an infeed conveyor has an end pivotally connected to a support for said first horizontal conveyor arm;

an outfeed conveyor has an end pivotally connected to a support for said second horizontal conveyor arm;

whereby, the weight of said infeed conveyor, first horizontal conveyor arm, and objects thereon are counterbalanced by the weight of said outfeed conveyor, second horizontal conveyor arm, and articles thereon via said means supporting said arms in counterbalanced relation to each other.

18. A conveyor system according to claim 15 wherein said system further includes means to drive said first conveyor arm and said infeed conveyor to transport articles in a first direction, and means to drive said second conveyor arm and said outfeed conveyor to transport articles in a second direction opposite to said first direction;

and means to actuate said means to drive said infeed conveyor and first conveyor arm in response to movement of said support to said second position.