A loading dock leveling apparatus including a ramp pivotable about its rear end and having a pivotable lip on its forward end. Apparatus is provided for projecting the lip outwardly after the ramp is raised beginning when the ramp is walked down to provide that the lip will engage the bed of a vehicle to be loaded or unloaded. The projecting apparatus includes a knuckle joint which pivots to projecting position on the ramp upswing and which is subsequently pivoted by a lever to release the projecting apparatus during the walk down but before the ramp descends to the highest serviceable vehicle level. A lip lock is provided for holding the lip in its projected position until the lip rests on the bed of the vehicle to be unloaded or until the ramp passes well below dock level and the lip lock is disengaged by a lip lock release.
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1. 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 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 tnan 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 notches wherein the surface means nearest the lip is shaped for preventing the pin from being relatively cammed from the slots notches as a result of force exerted by the weight of the lip acting on the plates.
16. lip lock means for maintaining a pivotable lip of a pivotable ramp associated with a loading dock in a projected position until released by (1) pivoting the lip to a position near parallel with the ramp or by (2) pivoting the lip end of the ramp to a downwardly inclined position to engage lip lock release means,
comprising in mechanically coupled relationship between the pivotable lip and ramp support means carrying an elongated pin in underlying relationship to the ramp and lip, an elongated plate having one end thereof pivotally supported to permit swinging movement thereof in a plane transverse to the axis of said pin disposed beneath the ramp and lip in longitudinally extending relationship thereto, said plate having formed therein a notch with an axis parallel to said pin and opening at a longitudinal edge of the plate for receiving said pin when the lip is pivoted to the projected position, said notch having surface means shaped to prevent the pin from being relatively cammed from the notch as a result of force exerted by the weight of the lip, a block disposed adjacent said plate in longitudinally slideable relationship thereto and having formed therein a groove with an axis parallel to said pin and opening at an edge surface to receive said pin when aligned with the notch in said plate, means securing said block in association with said plate to permit relative longitudinal displacement between said plate and block, said means including the U-shaped bracket secured to said block with the open end of said bracket facing toward the edge of said block at which the groove opens for retaining the pin in association with said block, said bracket being of a length and depth greater than said pin and secured to said block to permit relative displacement of said pin into and out of said groove and to permit relative longitudinal displacement of said pin along the aforesaid edge surface of said block between a position aligned with
said groove and a position not so aligned. 8. 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 means 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 pivoting 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 (2) the lip is pivoted to a position near parallel with the ramp; the improvement comprising:
the projection projecting means extending from the bar is and adjustable in length to cooperatively coordinate the release of the automatic lip pivoting means with the time that the lip lock means is positioned to support the lip in a projected position.
2. The lip lock means of
3. The lip lock means of
4. The lip lock means of
5. The lip lock means of
6. The lip lock means of
7. The lip lock means of
9. The combination of
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 notches as a result of force exerted by the weight of the lip acting on the plates.
10. The combination of
11. The combination of
12. The combination of
13. The combination of
support means carrying an elongated pin in underlying relationship to the ramp and lip, an elongated plate having one end thereof pivotally supported to permit swinging movement thereof in a plane transverse to the axis of said pin disposed beneath the ramp and lip in longitudinally extending relationship thereto, said plate having formed therein a notch with an axis parallel to said pin and opening at a longitudinal edge of the plate for receiving said pin when the lip is pivoted to the projected position, said notch having surface means shaped to prevent the pin from being cammed from the notch as a result of force exerted by the weight of the lip, a block disposed adjacent said plate in longitudinally slideable relationship thereto, and having formed therein a groove with an axis parallel to said pin and opening at an edge surface to receive said pin when aligned with the notch in said plate, means securing said block in association with said plate to permit relative longitudinal displacement between said plate and block, said means including a U-shaped bracket secured to said block with the open end of said bracket facing toward the edge of said block at which the groove opens for retaining the pin in association with said block, said bracket being of a length and depth greater than said pin and secured to said block to permit relative displacement of said pin into and out of said groove and to permit relative longitudinal displacement of said pin along the aforesaid edge surface of said block between a position aligned with said groove and a position not so aligned.
14. The combination of
15. The combination of
17. lip lock means according to
20. lip lock means according to
21. lip lock means according to
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Loading ramps to provide a bridge between a loading dock and the bed of a vehicle to be loaded or unloaded , 382-62-5, the lip lock apparatus 56 includes a pair of parallel plates 58 which are welded together in parallel position but spaced apart by spacers 60. Spacers 60 are of greater width than a block 62 interposed between the plates 58 and thus block 62 may slide longitudinally in the space between the plates 58. Bolts 64 are welded to each end of block 62 and the an elongated shallow U-shaped bracket 66 which is secured to the bottom of the block and serves to bear against the underside of plates 58 during the sliding motion of the block 62. A cover plate 68 positioned on the top of the block 62 and secured thereto by the bolts 64 serves a similar function on the top of the plates 58. The bracket 66 is and cover plate 68 are biased upward into contact with the respective lower and upper portions of the plates 58 by spring means 70 which circumscribe the threaded upper portion of bolts 64 and which are compressed by nuts 72.
The forward ends of plates 58 are pivotally supported in between downwardly projecting lugs 74 on the lip 32 and the rear portion is slidably supported on a pin 76 projecting between downwardly extending lugs 78 on the underside of the ramp 12. The pin projects through the space between the bottom of the block 62 and under the bracket 66 and the lower surface of the plates 58. For convenience in FIGS. 2-5, the nearer of the lug lugs 78 is not illustrated to better show the relative sequential movement of the pin, bracket and plates. Spring means 70 hold the bracket 66 stationary on the bottom edges of plates 58 except for movement forced by pin 76.
A downwardly opening groove 80 is formed in the underside of the block 62 to receive the pin 76 and downwardly opening notches 82 are formed on the underside of plates 58. The notches 82 being coaxial and axis of the notches and the axis of the groove 80 are parallel with in the two plates 58 are longitudinally aligned to cooperatively receive the pin 76 and, at one point in the relative movement of the plates 58 and block 62, these notches will align with the groove 80 for cooperative and concurrent receipt of the pin 76.
The pin 76 is designed to float within the shallow U-shaped bracket 66 and accordingly, the depth of the bracket 66 with respect to the bottom of the block 62 is greater than the diameter of the pin 76. The functions of the notches 82 and the groove 80 are to receive the pin 76 in locking engagement such that the weight of the lip 32 pressing against plates 58 through lugs 74 will not cam the pin 76 out of the slots bracket groove 80 by means of the notches 82 and back into the U-shaped bracket 66. Accordingly, it is necessary that the depth of the groove 80 76 and notches 82 be greater than the radius of the pin 80. To insure that the pin will not be cammed out of the notches the angle of the camming pressure should be at least 90°, that is, the forward edge surface should be perpendicular to the longitudinal axis of the plates 58.
In operation, a workman will cause the ramp 12 to be raised by pulling the chain 84 which releases the ramp hold down 30 and allows the spring 22 to bias swing or pivot the ramp upward to a fully raised position. He will then walk out on the ramp 12 to force it down and his weight will then cause the ramp to swing downwardly. If for some reason, he does not wish the lip 32 to project, he will first pull the chain 86 which will force the knuckle joint 48 over center to place the arm 36 and bar 46 in a relative position as in FIG. 9 where the arm 36 will be ineffective and will not project the lip 32 and the ramp will simply descend to with the lip 32 hanging downward in the position shown in FIG. 2 3 . However, as a general rule, the desire will be to project the lip. Accordingly, as the weight of the workman causes the ramp to descend, the arm 36, acting through lugs 44, will cause the lip 32 to swing upwardly with respect to the ramp 12 and project outward as the ramp 12 pivots downward as sequentially shown in FIGS. 6-9. The arm 36 will continue to project the lip until just after the bar 46 and arm 36 become a straight line at which time the knuckle joint 46 will 48 passes through center permitting the arm and bar to bend as shown in FIG. 9 and the force to project the lip 32 will be released.
Observing FIGS. 2-5, it will be seen that at the rest position of FIG. 2, with the lip 32 approximately perpendicular to the a ramp 12 and behind the keeper 88 secured to the frame 14, the pin 76 is at the forwardmost portion of the U-shaped bracket 66. Similarly, in FIG. 3 with the ramp raised to its maximum, the pin 76 is still forward because the lip 32 is still at an angle perpendicular to the ramp. As the lip projector projection arm 36 begins to project or swing the lip upwardly during the walk down, the plates 58 will be pulled forward by the lugs 74 and the pin 76 being held stationary by its supporting lugs 78 will slide to the rear of the U-shaped bracket to a point most remote from the lip since the block 66 is carried with the forwardly moving plates 58 through frictional clamping engagement of the bracket 66 and cover plate 68 with the two plates 58. At that point the bracket will be restrained against further movement with the plates 58 and will begin to slide along the plates. This movement continues until the pin pushes the bracket to a point where the upwardly opening U-shape moves under the notches 82 align with the groove 80 which was previously aligned with the pin 76. The weight of the apparatus 56 then causes it to fall such that the pin 76 moves into the aligned groove 80 and notches 82 as shown in FIG. 4. At this point in time or slightly thereafter, the lip projector is designed to release as the knuckle joint 48 passes equilibrium and flips over. The bolt 54 should be adjusted to provide that the knuckle joint 48 will not flip over until the pin 76 is engaged in the slots aligned groove 80 and notches 82. Thereby, lip lock apparatus 56 will then hold the lip 32 in projected position until the lip engages the bed of a truck or other vehicle 90 to be serviced. With the lip 32 engaging the bed of the truck 90 as shown in FIG. 5, the ramp 12 will continue to descend and the lip will be further pivoted or projected to a position near parallel with the ramp. During this sequence the rear sloping edge surface of the slot notches 82 will cam the pin 76 relatively downward and out of slot notches 82 and the block groove 80 and back into the U-shaped bracket 66 as the plates 58 are pulled even further forward and thus unlatches the lip lock apparatus. As the pin moves back, it will force plates 58 move relatively forward, the block 62 to the rear by pressing against the rear surface of the groove 80 and will become positioned further rearward on the plates when, at the full extension of the lip, the block will be almost to the rear of the plates 58 as shown in FIG. 5. It will be noted here that the plates 58, except when relatively positioned to align the notches 82 with the groove 80 and pin 76, will be supported on the pin 76 and will be free to slide on top of the pin.
When the truck 90 pulls away and the lip 32 is released thereby freed to fall to the perpendicular position, the pin will first move to the forward portion of the bracket 66 before it begins to drive the bracket forward. With the pin in the forward position of the bracket 66 it cannot slide into notches 82 because the block 62 at the forward portion of the bracket 66 prevents such vertical movement, groove 80 is not aligned with the pin, note particularly FIG. 10. with respect to the ramp 12, it will be seen that the lip lock apparatus 56 remains unlatched and ineffective and thus permit the lip to pivot downwardly. As the lip 32 pivots downwardly, the plates 58 will slide rearwardly along and be supported on the pin 76. During initial rearward movement of the plates 58, the block 62 will be carried rearwardly therewith through the frictional clamping engagement of the bracket 66 and cover plate 68. However, the block 62 will be restrained against further rearward movement when the pin 76 reaches the forward end of the bracket 66. Continued rearward movement of the plates 58 will result in the notches 82 moving into alignment with the pin 76 but the plates 58 will not drop because the groove 80 in the block 62 is not concurrently aligned therewith. The block 62 thus supports the plates 58 for continued rearward movement as the block is supported on the pin 76 and the plates are then supported on the bracket 66 carried by the block. Thus, the plates 58 may continue their rearward movement thereby permitting the lip to continue pivoting to its full down position.
A lip lock release means is provided for those occasions where the lip 32 is projected and locked into place but then there is some reason to release the lip without having engaged the bed of a truck or there is no truck at the dock. This release means is provided in the form of a bolt 92 projecting upward from the frame 14. When the ramp descends below the level of the surrounding dock, the lower surface of the bracket 66 will engage the top of the bolt 92. This will push the plates 58 and block 62 upward and disengage the pin 76 from the slots groove 80 and notches 82. at which time This unlatches the lock apparatus 56 as previously described and the lip 32 will fall by gravity to its pendant position.
Having thus described the invention in its preferred embodiment, it will be clear to those having ordinary skill in the art that obvious modifications may be made without departing from the spirit of the invention. Additionally, the language used to describe the invention is not considered limiting. Rather it is intended that the only limitations on the scope of the invention be as set out in the appended claims.
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| Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
| Mar 11 1977 | Harsco Corporation | (assignment on the face of the patent) | / | |||
| Apr 02 1990 | HARSCO CORPORATION, A CORP OF DE | Wayne-Dalton Corp | ASSIGNMENT OF ASSIGNORS INTEREST | 005422 | /0860 |
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