Blast cleaning arrangement

Claim 2

An abrasive blast cleaning arrangement comprising a blast station, abrasive blast means in said blast station, a load station on one side of said blast station, an unload station on the other side of said blast station, a first monorail between said load and said unload stations and extending through said blast station, a second monorail parallel to said first monorail, a variable speed tractor on said second monorail, a plurality of individual workpiece holders on said first monorail, each of said holders being disposed for carrying a workpiece into and out of said blast station for treatment by said blast means, disengageable coupling means on said tractor and each of said holders for selective engagement of said tractor with a holder whereby a plurality of said holders may be stacked together to form a stack of holders having a foremost holder and said tractor may convey one of said holders at elevated speed and then decrease its speed as said tractor approaches the stack of holders to release its holder and become coupled with the foremost holder of the stack.

Claim 3

An arrangement as set forth in claim 1 wherein each holder includes disengaging means for inactivating the coupling means on the subsequent holder when contacted by the subsequent holder whereby said tractor will be engaged with only the foremost holder in a stack of holders.

Claim 4

An arrangement as set forth in claim 2 including means at said blast station for rotating each of said holders when the holder is in said blast station.

Claim 5

An arrangement as set forth in claim 3 wherein said monorails are closed loops.

Claim 6

An arrangement as set forth in claim 4 wherein said second monorail is disposed above said first monorail.

Claim 7

An arrangement as set forth in claim 5 wherein said coupling means includes a downwardly projecting tongue on said tractor, an upwardly projecting lug on each holder in the path of motion of said tractor tongue, pivot means connecting said upwardly projecting lug for rotational movement caused by contact with said tractor tongue when said tractor tongue moves in a forward direction and for returning to its upstanding position when said tractor tongue moves past said lug to act as a stop for said tractor tongue when said tractor tongue moves in its backward direction, an upwardly projecting dog on each holder downstream from its lug in the path of motion of said tongue to abut against said tongue when said tongue moves in a forward direction to thereby cause its holder to move with said tractor, said disengaging means including an operating link connected to its dog for retracting its dog out of contact with said tongue upon actuation of said operating link, a cam tail on each holder in the path of motion of the operating link on the subsequent upstream holder for actuating that operating link when the adjacent holders are stacked together.

Claim 8

An arrangement as set forth in claim 6 wherein each of said holders includes sets of spaced wheels rollably mounted on said first monorail, a load bar interconnecting said sets of wheels, a rigid housing suspended from said load bar, a rotatable shaft in said housing, an exposed sprocket on said shaft for causing said shaft to rotate, work engaging means on said shaft, and said rotating means being a sprocket cHain at said blast station for engaging said sprocket to cause said sprocket to rotate upon movement of said chain.