Dock leveling apparatus

Claim 2

Lip lock means for maintaining a pivotable lip of a pivotable ramp associated with a loading dock in projected position until released by (1) pivoting the lip to a position near parallel with the ramp or (2) pivoting the lip end of the ramp to a downwardly inclined position to engage a lip lock release means, comprising, parallel plates secured together and sandwiching therebetween a block, the plates each being longer than the block and spaced apart by a width greater than the width of the block whereby the block is longitudinally slidable between the plates, means for securing the block in the space between the plates and the lower portion of the securing means comprising a bracket of a generally elongated shallow U-shape, the open end of the U-shaped bracket facing upward toward the lower edges of the plates, the bracket being attached to and slidable with said block, the front end of the plates being pivotally connected to the lip and the rear end of the plates being unattached, means associated with the deck for supporting a pin, said pin projecting through the space between the plates and the U-shaped bracket and thereby supporting the plates, the pin having a diameter less than the depth of the U-shaped bracket, a groove in the lower surface of the block having an axis parallel to the pin and a depth greater than the radius of the pin, the groove being located to open downwardly into the open face of the U-shaped bracket at the end of the bracket most remote from the lip, notches formed in the lower surfaces of each of the plates and of a depth greater than the radius of the pin, the notches in the two parallel plates having a common axis parallel with the pin, surface means forming the slots wherein the surface means nearest the lip is shaped for preventing the pin from being cammed from the slots as a result of force exerted by the weight of the lip acting on the plates.

Claim 3

The lip lock means of claim 1 wherein the surface of the notches most remote from the lip slopes to a smaller notch depth away from the lip to thereby cam the pin out of the notches as the lip pivots toward a plane parallel with the ramp.

Claim 4

The lip lock means of claim 2 wherein the lip lock release means comprises means for blocking the descent of the plates relative to the descent of the pin.

Claim 5

The lip lock means of claim 3 wherein the U-shaped bracket is of a width greater than the width between the plates.

Claim 6

The lip lock means of claim 4 in combination with automatic lip projecting and release means for raising the lip relative to the ramp until the pin moves into the slot and thereafter releasing the lip to be supported by the pin.

Claim 7

The lip lock means of claim 1 in combination with automatic lip projecting and release means for raising the lip relative to the ramp until the pin moves into the slot and thereafter releasing the lip to be supported by the pin.

Claim 8

The lip lock means of claim 1 wherein the lip lock release means comprises means for blocking the descent of the plates relative to the descent of the pin.

Claim 9

In the combination of dock leveling apparatus associated with a loading dock which is designed for loading and unloading vehicles; the loading dock having a generally planer upper surface; the apparatus including a ramp having front and rear portions and pivotally mounted at its rear portion; means associated with the ramp for releasibly blocking the upward movement of the ramp; means for pivoting the ramp upward upon release of said blocking means; lip means pivotally attached to the front portion of the ramp, said lip being for bridging the gap between the ramp and a bed of a vehicle and for limiting the descent of the front portion of the ramp below said bed; means for limiting the angle of pivot of the lip means from approximately parallel with the ramp to about a downwardly extending right angle with the ramp; means for automatically pivoting the lip upwardly from its right angle position to a projected position following (a) release of the ramp blocking means and (b) the upward pivoting movement of the ramp and during subsequent downward pivoting movement of the ramp; the automatic lip pivoting means comprising a straight arm pivoted from both ends, one end being pivoted from the lip and the other end pivoted from a short bar, the short bar being pivotally anchored to a substrate, said substrate being stationary relative to said dock, projecting means extending from the bar intermediate its pivot points for limiting the pivoting of said bar toward the substrate and means for releasing the automatic lip pivoting means during the ramp descent while the front portion of the ramp is above the level of the dock; lip lock means for maintaining the lip in projected position after the automatic lip pivoting means is released and until (1) the front portion of the ramp descends below the level of the dock to engage lip lock release means or (2) the lip is pivoted to a position near parallel with the ramp; the improvement comprising: the projection means extending from the bar is adjustable in length to cooperatively coordinate the release of the automatic lip pivoting means with the time the lip lock means is positioned to support the lip in projected position.

Claim 10

In the combination of dock leveling apparatus associated with a loading dock which is designed for loading and unloading vehicles; the loading dock having a generally planer upper surface; the apparatus including a ramp having front and rear portions and pivotally mounted at its rear portion; means associated with the ramp for releasibly blocking the upward movement of the ramp; means for pivoting the ramp upward upon release of said blocking means; lip means pivotally attached to the front portion of the ramp, said lip being for bridging the gap between the ramp and a bed of a vehicle and for limiting the descent of the front portion of the ramp below said bed; means for limiting the angle of pivot of the lip means from approximately parallel with the ramp to about a downwardly extending right angle with the ramp; means for automatically pivoting the lip upwardly from its right angle position to a projected position following (a) release of the ramp blocking means and (b) the upward pivoting movement of the ramp and during subsequent downward pivoting movement of the ramp; the automatic lip pivoting means comprising a straight arm pivoted from both ends, one end being pivoted from the lip and the other end pivoted from a short bar, the short bar being pivotally anchored to a substrate, said substrate being stationary relative to said dock, projecting means extending from the bar intermediate its pivot points for limiting the pivoting of said bar toward the substrate and means for releasing the automatic lip pivoting means during the ramp descent while the front portion of the ramp is above the level of the dock; lip lock means for maintaining the lip in projected position after the automatic lip pivoting means is released and until (1) the front portion of the ramp descends below the level of the dock to engage lip lock release means or (2) the lip is pivoted to a position near parallel with the ramp; the improvement comprising: the projection means extending from the bar is adjustable in length to cooperatively coordinate the release of the automatic lip pivoting means with the time the lip lock means is positioned to support the lip in projected position.

Claim 11

The combination of claim 8 wherein the lip lock means comprises parallel plates secured together and sandwiching therebetween a block, the plates each being longer than the block and spaced apart by a width greater than the width of the block whereby the block is longitudinally slidable between the plates, means for securing the block in the space between the plates and the lower portion of the securing means comprising a bracket of a generally elongated shallow U-shape, the open end of the U-shaped bracket facing upward toward the lower edges of the plates, the bracket being attached to and slidable with said block, the front end of the plates being pivotally connected to the lip and the rear end of the plates being unattached, means associated with the ramp for supporting a pin, said pin projecting through the space between the plates and the U-shaped bracket and thereby supporting the plates, the pin having a diameter less than the depth of the U-shaped bracket, a groove in the lower surface of the block having an axis parallel to the pin and a depth greater than the radius of the pin, the groove being located to open downward into the open face of the U-shaped bracket at the end of the bracket most remote from the lip, notches formed in the lower surfaces of each of the plates and of a depth greater than the radius of the pin, the notches in the two parallel plates having a common axis parallel with the pin, surface means forming the notches whereby the surface means nearest the lip is shaped for preventing the pin from being cammed from the slots as a result of force exerted by the weight of the lip acting on the plates.

Claim 12

The combination of claim 9 wherein the projection means extending from the bar is adjustable in length to cooperatively coordinate the release of the automatic lip pivoting means with the time the pin moves into the notches in the lip lock means.

Claim 13

The combination of claim 8 wherein the straight arm of the automatic lip pivoting means comprises coaxially mounted tubes, said tubes allowing an angular swing of the ramp greater than needed for the lip to rise above the truck bed, means biasing the tubes together.

Claim 14

The combination of claim 8 wherein the lip is pivoted from the ramp by hinge means and the ramp extends horizontally beyond the hinge means to guard the pivot axis against falling material, ice and the like which might impair the pivoting movement.