US3475778A - Dockboard - Google Patents

Dockboard Download PDF

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Publication number
US3475778A
US3475778A US642089A US3475778DA US3475778A US 3475778 A US3475778 A US 3475778A US 642089 A US642089 A US 642089A US 3475778D A US3475778D A US 3475778DA US 3475778 A US3475778 A US 3475778A
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Prior art keywords
latch
plate
lip
main plate
movement
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US642089A
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English (en)
Inventor
John A Merrick
Adrian P Hovestad
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Service Steel & Eng Ltd
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Service Steel & Eng Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
    • B65G69/00—Auxiliary measures taken, or devices used, in connection with loading or unloading
    • B65G69/28—Loading ramps; Loading docks
    • B65G69/2805—Loading ramps; Loading docks permanently installed on the dock
    • B65G69/2811—Loading ramps; Loading docks permanently installed on the dock pivoting ramps
    • B65G69/2835—Loading ramps; Loading docks permanently installed on the dock pivoting ramps with spring-operated means
    • B65G69/2841—Loading ramps; Loading docks permanently installed on the dock pivoting ramps with spring-operated means extensible by pivoting parts

Definitions

  • a new dockboard has a ramp assembly comprising a main plate pivoted to the dockboard frame, and a lip plate at the front of the main plate; means for automatically extending the lip plate comprise a latchable telescoping assembly disposed beneath the main plate, the telescoping assembly changing length as the main plate moves about its pivot, and the latch being operative during pivoting movement of the main plate in one direction to prevent telescoping of the assembly, so that it operates to extend the lip plate.
  • a ramp assembly comprises a main plate pivoted to frame means and a lip plate disposed at the front edge of the main plate, and means are provided for automatically extending the lip plate from a stored inoperative position to an extended operative position in which it forms an extension of the main plate.
  • a new dockboard comprising frame means, a main plate having a front edge, means pivotally connecting the main plate with the said frame means for pivoting movement about a respective rst pivot axis, a lip plate, means mounting the lip plate at the main plate front edge for movement relative to the main plate between a stored position and an operative extended position, and lip-extending means operative to move the lip plate from its stored position to its operative position upon movement of the main plate about said rst pivot axis, said lipextending means comprising, telescoping means connected to the said frame means at a point spaced from said first pivot axis and to the lip plate so that movement of the main plate about the rst pivot axis attempts to change the length of the said telescoping means, and a rst latch means operative over a predetermined range of movement of the main plate to latch the said telescoping means against change of length and thereby cause the telescoping means to move the lip plate to its extended position.
  • the lip plate rear edge is pivoted to the main plate front edge, so that the" lip plate pivots about a respective second pivot axis relative to the main plate between the said stored and extended positions.
  • a new dockboard comprising frame means, a main plate having a front edge, means pivotally connecting the main plate with the said frame means for pivoting movement about a respective lirst pivot axis, a lip plate, means mounting the lip plate at the main plate front edge for movement relative to the main plate between a stored position and an operative extended position, lip-extending means operative to move the lip plate from its stored position to its operative position upon movement of the main plate about the said lirst pivot axis, an arm connected with the said lip plate and movable thereby, and a reaction member on the frame means disposed for cooperating engagement with the said arm, whereby movement of the lip plate to return to its stored position causes engagement of the arm and the reaction member and the consequent application to the lip plate and thereby to the main plate of a vertically-upwardly-directed force that moves the main plate above its stored position, so that the main plate can thereafter descend under gravity to its stored position with the lip plate in its respective stored position.
  • FIGURE 1 is a general perspective view showing the dockboard ramp assembly in its stored position
  • FIGURE 2 is a view similar to FIGURE 1 and showing the ramp assembly in a typical operative position
  • FIGURE 3 is a plane section taken on the line 3 3 of FIGURE 1 to show the spring-counterbalance and manual lever-handling arrangements
  • FIGURE 4 is a plane section taken on the line 4-4 of FIGURE 1 to show the arrangement of the lip-extending mechanism with the ramp assembly in the said stored position
  • FIGURE 5 is a perspective view to an enlarged scale of a detail of the said lip-extending mechanism
  • FIGURE 6 is a view similar to FIGURE 4 with the ramp assembly in a rst latch latching position and the mechanism set to raise the lip plate,
  • FIGURE 7 is a View similar to FIGURES 4 and 6 illustrating the raising of the lip plate by the mechanism as the ramp assembly descends from the position of FIG. 6,
  • FIGURE 8 illustrates the operation of the ymechanism to restore the lip plate to its dependent position and the ramp assembly to its stored position when the latter descends below a predetermined second latch unlatching position
  • FIGURE 9 shows a lower storage position to which the ramp assembly can be put when required
  • FIGURE 10 illustrates the operation of a safety latch feature in the event that a transport backs against the lip plate while in the latched extended position
  • FIGURE 11 is a perspective view from below and to an enlarged scale of a detail of the latch arrangement of the lip-extending mechanism
  • FIGURE 12 is a cross-sectional view of part of another embodiment wherein the lip plate slides relative to the main plate between the stored and extended positions.
  • the particular form of dockboard shown herein is adapted to be mounted as an integral unit into a recess in a loading dock or platform so that, with the ramp assembly in -the position shown in FIGURES 1 and 3 (called herein its stored position), the main plate 16 thereof is approximately level with the top surface of the dock, and the lip plate 17 is folded down to be lapproximately flush with the front face of the dock.
  • the term stored position is used for convenience and under some conditions the dockboard will be operative for loading and unloading while in the so-called stored position.
  • the invention also is applicable to other forms of dockboard, such as a free-standing unit without a surrounding dock, and a unit of the type especially adapted for use with a stepdown dock.
  • frame means is used herein for convenience in terminology, and in the embodiment illustrated comprises a box-like frame assembly; in other embodiments the frame means may instead comprise, for example, only the means by which the ramp assembly and its associated mechanism are fastened to a suitable supporting structure, which may be the dock, in which case the said supporting structure operatively connects the fastening means together.
  • This particular dockboard comprises a frame assembly 18 of welded sheet metal, made sufiiciently rigid for transport, installation and subsequent use in known manner, as by suitable strengthening edges and cross bracing members such as 19; with this embodiment the frame assembly when installed is supported by the surrounding concrete of the dock 15.
  • the main plate 16 has its rear edge hinged to the frame assembly by a pivot 20, the axis of the pivot being horizontal.
  • the lip plate is hinged to the front edge of the main plate by a pivot 21 having its axis parallel to that of the pivot 20. Referring especially to FIGURES 1, 3 and 4, in the stored position illustrated the main plate is horizontal and the lip plate is generally vertical, in what is called herein its dependent position, with its front edge engaged behind a pair of spaced stops 22.
  • Spring means 'comprising one or more heavy helical compression springs 23 are connected between a member 24 fixed to the frame 18 and a bracket 25 fixed to the underside of the main plate.
  • Two extreme positions of this particular ramp assembly (called herein its first latch latching and second latch unlatching positions) are shown respectively in FIGURES 6 and 8, and it will be seen that as the springs 23 shorten and provide more spring force their upwardly-acting component is reduced; the arrangement of these spring means is made such that, in all positions of the ramp assembly whether the lip plate is in the said extended or in the said dependent position, the effective Weight of the assembly just overcomes the bias of the spring means. With the lip plate in extended position, as shown in FIGURE 7, the effective Weight of the ramp assembly acting against the spring means is increased, whereupon the assembly moves more positively downward.
  • the ramp assembly of this embodiment is moved by hand and to facilitate its handling a lever handle 26 is provided, the handle vbeing movable longitudinally through a slot 27 in the main plate, from a stored position shown in FIGURE 3 in broken lines to an operative position shown in solid lines. In the stored position the lever is completely concealed beneath the main plate so that it does not obstruct the passage of traffic.
  • a ring 28 permits the operator to grasp the lever and also engages a bracket 29 to retain the lever in its lowermost position.
  • the lip-extending mechanism comprises a telescoping arm assembly constituted by an outer, hollow, square 4 cross-section member 30 pivoted at its rear end to th frame assembly by a pivot 31, the axis of the pivot being parallel to and spaced vertically from the axis of pivot 20.
  • An inner, hollow, square cross-section member 32 slides freely inside the outer member 30, and another outer, hollow, square cross-section member 33 slides freely over an extension 32a: (FIGURE 10) at the front end of the inner member 32.
  • a relatively stiff helical spring 34 is mounted in the enclosure formed between the extension 32a and the hollow member 33 and constantly urges the member 33 in the forward direction.
  • a bolt 35 passes freely through a 'cross piece 36 at the end of the inner member 32 and carries at its other end a clevis 37, which is connected by a pivot 38 to a depending arm 39 rigid with the lip plate 17.
  • the engagement of the cross piece 36 and the head of the bolt 35 limits the forward movement of the latter, while the compression of the spring 34 is adjusted by means of nuts 40.
  • a first gravity-operated latch member 41 is pivoted to the frame about the same pivot 31 as the telescopic arm assembly and comprises a nose-piece 42 (see especially FIGURE 5) that will pass through a slot 43 in the outer member 30 to engage behind the rear end of the inner member 32.
  • An extension 44 of the member 41 extends to one side of the outer member 30, and in a predetermined lower range of movement of the ramp assembly engages an upwardly-biased, latch-disengaging plunger 45 mounted in a channel 46 fixed to the frame assembly, the plunger being urged upwardly by a surrounding spring 47.
  • a second gravity-operated latch member comprises an arm 48 pivoted at 49 to a bracket 50 that is in turn fastened to the inner member 32 and movable therewith.
  • a latch nose at the rear end of the arm 48 can engage a latch plate 52 fixed t0 shaft 53 which is pivotally mounted by brackets 54 (FIGURE 11) to the underside of the main plate.
  • the mounting of the plate 52 on its shaft is such that rearwardly-acting force on the arm 48 acts along a line passing through the pivot axis of the shaft, and there is no tendency for the shaft to rotate under the action of this force and release the latch.
  • a downward extension 55 fixed to the shaft 53 is engageable in certain positions of the ramp assembly via a screw 56 with a disengagement member 57 fixed to one side of the outer member 30, the screw permitting adjustment of the actual point of engagement between itself and the member 57.
  • a mechanism for restoring the ramp assembly automatically to its stored condition comprises an arm 58 which is pivoted at 59 to a depending portion of the bracket 50, and which has an extension 60 and a cam nose 61 that engage in predetermined positions of the ramp assembly with a reaction member 62 fastened to the frame means, in this embodiment fastened to the frame oor.
  • the lowermost position to which the arm 58 can fall under gravity about the pivot 59 is set by a screw 63,
  • the spring 34 It is an important function of the spring 34 that if the second latch has not engaged by the time that the lip plate is at its maximum extension, the spring will compress under further downward movement of the main plate and shorten the telescopic arm the small amount required for this latching to take place; the spring thereby ensures the successful operation of the second latch without the need for extreme criticality in manufacturing and setting tolerances.
  • the plunger 45 has engaged the latch extension 44, but the spring 47 is too weak to disengage the first latch while it is still under the load imposed by the ramp assembly. Any further downward movement of the ramp assembly can only take place by compressing the spring 34, and such compression takes place until the weight of the ramp assembly that is not neutralized by the main spring means 23 is fully taken up by the spring 34.
  • the dockboard is now in a tioating condition at which its weight is fully neutralized by springs; if at this point the ramp assembly is given even a slight upward jerk or push to what is called a iirst latch unlatching position, the telescoping arm assembly elongates sufficiently to unload the iirst latch and allow the plunger 45 to push the latch arm 41 out of engagement.
  • this oating condition can only be achieved by moving the ramp very slowly, and at the usual speed of operation the additional downward force, due to the kinetic energy of the assembly, always overloads the spring 34, which promptly bounces and lifts the ramp assembly a distance suiiicient to unload the iirst latch, the whole action taking place quickly and smoothly.
  • the extent of possible downward movement of the plunger 45 is limited and after the plunger has moved its full extent it will stop and positively force the member 41 out of engagement and unlatch the first latch.
  • the lip plate is now held extended by the second latch means, which are operative between the main and lip plates, so that the lip plate will remain in the same attitude relative to the main plate during movement of the ramp assembly between what is called herein its upper operative position (approximately the position shown in solid lines in FIGURE 7) and its lower operative position (approximately the position shown in solid lines in FIGURE 8).
  • the ramp assembly now moves gently down ward under its own weight to the position shown in broken lines in FIGURE 7, in which the lip plate rests on the transport 64 to permit movement of wares, etc. over the assembly between the truck and the dock.
  • the body of a loaded transport will rise as it is unloaded, and vice versa, and the ramp assembly can rise and fall with the transport body without change of its attitude.
  • a particularly advantageous feature of our new dockboard is that it will return automatically to its stored position of FIGURE 4 upon the transport driving away from the dock, even when the final operative position of the ramp assembly is below the stored position.
  • the ramp assembly moves downward (arrow 69) the second latch member 55 moves rearward relative to the outer arm member 30,
  • the action of the propping means is therefore that, as soon as the second latch is released, a portion of the weight of the lip plate is relieved from the ramp assembly and carried directly by the frame means via the propping means.
  • the spring means 23 thereupon moves the main plate upward, moving the pivot 21 and the corresponding rear edge of the lip plate upward, the prop means remaining meanwhile in engagement with the block 62.
  • the pivot 59 and the associated end of the arm 58 move upward with the upward movement of the main plate, causing the extension 60 to pivot against the top face of the block 62 and lift the nose 61.
  • the arrangement is such that as the main plate reaches a position which is just above the stored position (i.e. the position shown in broken lines in FIGURE 8) the nose is lifted clear of the block, whereupon the propping means are no longer effective.
  • the weight of the ramp assembly now overcomes the spring means and the assembly moves downward, moving the nose 61 over the top of the block so that the prop cannot obstruct the downward movement.
  • FIG- URE 7 To show that it is a propping action which is obtained reference may be made to the situation illustrated by FIG- URE 7, wherein the lip plate is resting on the transport 64, the transport constituting the propping means. If at this time the second latch is manually disengaged the main plate immediately lifts, dragging the forward edge of the lip plate rearward over the transport oor until the edge clears the floor, whereupon ⁇ the lip plate drops directly to the stored position and the ramp assembly drops directly downward.
  • a key member 74 having two parallel arms 75 and 76 is mounted for both longitudial and rotational movement in a bracket 77 fixed to the underside of the main plate 16.
  • This key member can be used to unlatch the second latch, and for this purpose the operator reaches through a slot 78 in the ramp plate, grasps the key member 74, lifts it vertically, and then rotates it anticlockwise (arrow 79) as seen in FIGURE 11, so that the arm is aligned with a rearward extension 80 on the latch shaft 53; the key member is now pushed downward a distance suicient to rotate the shaft 53 until the second latch is released.
  • the action of the unlatched lip plate and the counterbalance spring means is to cause the main plate to lift and the lip plate to move back toward its stored dependent position, its front edge sliding on the transport floor; when the lip plate leaves the transport floor it immediately falls to its fully dependent position and the whole ramp assembly then moves downward, either under its own weight or with the assistance of the operator if required, until it has reached the stored position of FIGURE 4.
  • the telescoping arm assembly is now latched against change of length, and as the assembly is lowered the lip plate is elevated a suflicient amount for its lower edge to clear the upper stops 22. Thereafter the key 74 is pushed downward until the latch members 81 and 82 are disengaged by the action of a stop 76]; on the arm 76; the lip plate now pivots toward the dock and can be engaged with the lower stop 22a, as seen in FIGURE 9.
  • a safety mechanism to guard against this possibility employs a third safety latch, comprising an arm 8-3 pivoted at 84 to an assembly 85 carried on the member 33.
  • a latch nose 86 at the rear end of the arm 83 is arranged to engage a latch plate 87 on the rod 53 just before the second latch becomes engaged. Any rearward movement of the transport 64 (arrow 88) causes corresponding movement of the member 33, assembly 8S and arm 83 (arrow 89); the
  • the lip plate 17 is pivoted to the main plate 16 and is dependent therefrom in its Stored position.
  • the invention also is applicable to a dockboard having a ramp assembly of the type illustrated by FIGURE 12, wherein the lip plate is moved by the telescoping arm assembly from an extended position shown in solid lines to a stored position shown in broken lines and in which it is accommodated beneath the main plate, the lip plate being mounted by guides 88 for sliding movement between the two positions.
  • the ramp assembly is moved manually, and spring means 23 are employed to oppose its weight and make it capable of operation by a single operator of average strength.
  • the invention also is applicable to a dockboard in which the assembly is counterbalanced by a weight and/or the movement of the assembly is by means of a motor, such as a hydraulic or pneumatic piston and cylinder.
  • a motor such as a hydraulic or pneumatic piston and cylinder.
  • the motor may be operated to raise the assembly to the position of FIGURE 6 and then shut off, whereupon the assembly will move ⁇ downwards under its own weight, elevating the lip plate at the same time; it will usually be desirable to arrange that the motor also controls the downward movement so that the assembly can be lowered gently to the required position.
  • the telescoping means are operative to extend the lip plate as the main plate descends, but it is also possible for them to extend the lip as the main plate is raised, by simple reversal of the direction of action of the connection between the telescoping arm means and the lip plate.
  • the upward movement of the main plate causes the telescoping arm means to decrease in length instead of increase, and the first latch means then are operative to prevent an increase in the length of the telescoping arm means, as they are operative to extend the lip upon upward or downward movement of the main plate about its pivot axis.
  • a dockboard comprising frame means, a main plate having a front edge, means pivotally connecting the ramp plate with the said frame means for pivoting movement about a respective first pivot axis, a lip plate, means pivotally mounting the lip plate at the main plate front edge about a second pivot axis for movement relative to the main plate between a stored position and an operative extended position, and lip-extending means operative to move the lip plate from its stored to its operative position upon movement of the main plate about said first pivot axis, said lip-extending means comprising telescoping means connected to the said frame means at a point spaced from said first pivot axis and to the lip plate so that movement of the main plate about the first pivot axis attempts to change the length of the said telescoping means, a first latch means operatively connected between the frame means and said arm means and operative over a predetermined range of movement of the main plate to latch the said telescoping means against change of length and thereby cause the telescoping means to move the lip plate to its extended position, and second
  • means for unlatching the second latch means upon movement of the ramp plate below a predetermined position comprises disengagement means movable with the said first telescoping member and operatively engageable with the said latch rotatable member to rotate the latter and thereby unlatch the latch.
  • a dockboard as claimed in claim l wherein means for unlatching the first latch means comprise a spring loaded plunger engageable with the first latch over a predetermined lower range of movement of the main plate, and the said telescoping means includes spring means compressible in the direction of telescoping motion of the telescoping means by the load of the ramp assembly, the load of the assembly upon the first latch holding it in engagement against the action of the said plunger, and the said spring means permitting unloading of the first latch whereupon the plunger can unlatch the said first latch.
  • a dockboard as claimed in claim 1 comprising spring means operably connected between the frame means and the ramp assembly and urging the assembly for upward movement, said spring means normally being unable to move the ramp assembly upward against the weight thereof acting downward under gravity, prop means operably engageable between the lip plate and the frame means upon movement of the main plate below a lower operating position, said prop means in said operative engagement relieving the spring means of at least part of the weight of the ramp assembly such that the spring means moves the ramp assembly upward above its said stored position, and prop disengaging means disengaging the prop means from between the lip plate and the frame means upon movement of the ramp assembly above the stored position, so that the ramp assembly thereafter descends under gravity to its stored position.
  • the telescoping means comprise, a first telescoping member pivoted to the frame means, a first latch member pivoted to the frame means, a second telescoping member pivotally connected with the lip plate and telescoping with respect to the rst member, the second member being engageable with the said first latch member to constitute rst latch means, a second latch member carried by the second telescoping member, another second latch member mounted on the underside of the main plate and engageable with the first mentioned second latch member to constitute said second latch means, the first latch being latched upon upward movement of the ramp assembly above a first latch latching position and the second latch being latched upon downward movement of the ramp assembly to a second latch latching position above an upper operative position of the ramp assembly, means for unlatching the first latch means upon movement of the ramp assembly to a first latch unlatching position below the said second latch latching position, and means for unlatching the second latch means upon movement of the ramp assembly to a second
  • a dockboard comprising frame means, a main plate having a front edge, means pivotally connecting the ramp plate with the said frame means for pivoting movement about a respective first pivot axis, a lip plate, means mounting the lip plate at the main plate front edge for movement relative to the main plate between a stored position and an operative extended position, and lip-extending means operative to move the lip plate from its stored to its operative position upon movement of the main plate about the said first pivot axis, said lip-extending means comprising arm means operatively engageable with the frame means and the lip plate, first latch means operable over a predetermined range of movement of the main plate to latch the arm means to the frame means for the arm means to move the lip plate to the operative position upon the said movement of the main plate over the predetermined range, first latch unlatching means operably engageable with the first latch means over another predetermined range of movement of the main plate to urge said latch means to unlatched condition, said unlatching means being inoperative while the first latch means is loaded by the ramp assembly and being operative
  • a dockboard as claimed in claim 15, wherein the said lip-extending arm means comprises spring means interposed between the lip plate and the first latch means for unloading the ramp assembly from the first latch means by spring action of the spring means during movenent of the ramp assembly and subsequent reaction thereo 18.
  • the lip plate has front and rear edges, the lip plate rear edge is pivoted to the main plate front edge so that the lip plate pivots about a respective second pivot axis relative to the main plate between the said stored and extended positions, and the said lip-extending arm means are latched by the first latch means to the frame means as the main plate moves downward from an uppermost position, so that downward movement of the main plate is accompanied by extension of the lip plate.
  • said iirst latch means comprise a latch member mounted bythe frame means
  • said unlatching means comprises a spring urged plunger mounted by the frame means for operative engagement with the said latch means, and urging the latch member to unlatch the latch means.
  • a dockboard as claimed in claim 17, comprising second latch means having relatively movable latch members and operatively connected by the lip-extending arm means between the main plate and the lip plate to latch the lip plate in the said extended position when it has been moved to that position, and wherein the said spring means is also interposed between the lip plate and the second latch means and permits relative movement of the second latch means latch members for latching thereof after the lip plate has moved to the said extended position.
  • a dockboard comprising frame means, a main plate having a front edge, means pivotally connecting the ramp plate with the said frame means for pivoting movement about a respective rst pivot axis, a lip plate, means mounting the lip plate at the main plate front edge for movement relative to the main plate between a stored position and an operative extended position, and lip-extending means operative to move the lip plate from its stored to its operative position upon movement of the main plate about the said lirst pivot axis, said lip-extending means comprising arm means operatively engageable with the frame means and the lip plate, rst latch means operable over a predetermined range of movement of the main plate to latch the arm means to the frame means and cause the arm means to move the lip plate to the operative position upon the movement of the main plate over the said predetermined range thereof, second latch means having relatively movable latch members and operatively connected by the arm means between the main plate and the lip plate to latch the lip plate in the said extended position when it has been moved to that position, and said arm
  • a dockboard comprising frame means, a main plate having a front edge, means pivotally connecting the ramp plate with the said frame means for pivoting movement about a respective lirst pivot axis, a lip plate, means mounting the lip plate at the main plate front edge for movement relative to the main plate between a stored position and an operative extended position, and lip-extending means operative to move the lip plate from its stored to its operative position upon movement of the main plate about the said first pivot axis, spring means operatively connected between the frame means and the ramp assembly and urging the assembly for upward movement, said spring means normally being unable to move the ramp assembly upwards against the weight thereof acting downward under gravity, and prop means operably engageable between the lip plate and the frame means upon movement of the main plate below a lower operating position, said prop means in said operative engagement relieving the spring means of at least part of the weight of the ramp assembly such that the spring means moves the ramp assembly upward above its said stored position.
  • a dockboard comprising frame means, a main plate having a front edge, means pivotally connecting the ramp plate with the said frame means for pivoting movement about a respective iirst pivot axis, a lip plate, means mounting the lip plate at the main plate front edge for movement relative to the main plate between a stored position and an operative extended position, lip-extending means operative to move the lip plate from its stored to its operative position upon movement of the main plate about the said irst pivot axis, said lip-extending means comprising arm means operatively engageable with the frame means and the lip plate, first latch means operable over a predetermined range of movement of the main plate to latch the arm means to the frame means and cause the arm means to move the lip plate to the operative position upon the movement of the main plate over the said predetermined range thereof, second latch means operatively connected by the lip-extending arm means between the main plate and the lip plate to latch the lip plate in the said extended position when it has been moved to that position, and safety latch means connected to and movable with

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  • Mechanical Engineering (AREA)
  • Auxiliary Methods And Devices For Loading And Unloading (AREA)
US642089A 1967-05-29 1967-05-29 Dockboard Expired - Lifetime US3475778A (en)

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US3662416A (en) * 1970-12-29 1972-05-16 Serco Eng Ltd Dockboards
US3671990A (en) * 1970-06-23 1972-06-27 Adrian P Hovestad Self-extending dockboard
US3786530A (en) * 1971-06-24 1974-01-22 T & S Equipment Co Dock leveler
US3967337A (en) * 1975-03-25 1976-07-06 Kelley Company, Inc. Return to dock level mechanism for a dockboard
US3982295A (en) * 1975-05-21 1976-09-28 Harsco Corporation Dock leveling apparatus
US3997932A (en) * 1974-12-13 1976-12-21 Kelley Company, Inc. Dockboard having improved lip lifting mechanism
US4010505A (en) * 1975-09-11 1977-03-08 Richards-Wilcox Of Canada Limited Dockboards
US4047258A (en) * 1976-12-03 1977-09-13 Harsco Corporation Lip lock with release and counterbalance for dock board
USRE30104E (en) * 1975-05-21 1979-10-02 Harsco Corporation Dock leveling apparatus
US4398315A (en) * 1981-12-21 1983-08-16 Kelley Company, Inc. Yieldable and releasable lip lifting mechanism for a dockboard
US5303443A (en) * 1992-04-02 1994-04-19 The Serco Corporation Dock leveler hold-down system
US5440772A (en) * 1993-07-23 1995-08-15 Rite-Hite Corporation Vehicle-activated safety leg control system for a dock leveler assembly
US5657716A (en) * 1995-12-04 1997-08-19 Dock Leveler Manufacturing Signaling device for a dock leveler system
US5774920A (en) * 1996-05-20 1998-07-07 United Dominion Industries, Inc. Electrically actuated dock leveler
US6085375A (en) * 1998-06-22 2000-07-11 Rite-Hite Holding Corporation Lip guiding mechanism for dock levelers
US6327733B1 (en) * 1999-12-10 2001-12-11 United Dominion Ind, Inc. Mechanically actuated dock leveler with hydraulic assist
US20040237223A1 (en) * 2003-05-27 2004-12-02 United Dominion Industries, Inc. Vertically-storing dock leveler apparatus and method
US20050011020A1 (en) * 2003-05-27 2005-01-20 Spx Corporation Vertically-storing dock leveler apparatus and method
US20050060821A1 (en) * 2003-09-22 2005-03-24 United Dominion Industries, Inc. Spring counterbalance method and apparatus for variably biasing a dock leveler
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US7032267B2 (en) 2004-05-11 2006-04-25 Rite-Hite Holding Corporation Dock leveler with combination safety leg and lip deflector
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US3636578A (en) * 1969-06-20 1972-01-25 Overhead Door Corp Spring counterbalanced compact dockboard
US3671990A (en) * 1970-06-23 1972-06-27 Adrian P Hovestad Self-extending dockboard
US3662416A (en) * 1970-12-29 1972-05-16 Serco Eng Ltd Dockboards
US3786530A (en) * 1971-06-24 1974-01-22 T & S Equipment Co Dock leveler
US3997932A (en) * 1974-12-13 1976-12-21 Kelley Company, Inc. Dockboard having improved lip lifting mechanism
US3967337A (en) * 1975-03-25 1976-07-06 Kelley Company, Inc. Return to dock level mechanism for a dockboard
USRE30104E (en) * 1975-05-21 1979-10-02 Harsco Corporation Dock leveling apparatus
US3982295A (en) * 1975-05-21 1976-09-28 Harsco Corporation Dock leveling apparatus
US4010505A (en) * 1975-09-11 1977-03-08 Richards-Wilcox Of Canada Limited Dockboards
US4047258A (en) * 1976-12-03 1977-09-13 Harsco Corporation Lip lock with release and counterbalance for dock board
US4398315A (en) * 1981-12-21 1983-08-16 Kelley Company, Inc. Yieldable and releasable lip lifting mechanism for a dockboard
US5303443A (en) * 1992-04-02 1994-04-19 The Serco Corporation Dock leveler hold-down system
US5440772A (en) * 1993-07-23 1995-08-15 Rite-Hite Corporation Vehicle-activated safety leg control system for a dock leveler assembly
US5657716A (en) * 1995-12-04 1997-08-19 Dock Leveler Manufacturing Signaling device for a dock leveler system
US5774920A (en) * 1996-05-20 1998-07-07 United Dominion Industries, Inc. Electrically actuated dock leveler
US6085375A (en) * 1998-06-22 2000-07-11 Rite-Hite Holding Corporation Lip guiding mechanism for dock levelers
US6327733B1 (en) * 1999-12-10 2001-12-11 United Dominion Ind, Inc. Mechanically actuated dock leveler with hydraulic assist
US7603733B2 (en) * 2002-10-29 2009-10-20 Stertil B.V. Dock leveller, lip for dock leveller and lip hinge construction
US20060150348A1 (en) * 2002-10-29 2006-07-13 Wybe Laverman Dock leveller, lip for dock leveler and lip hinge construction
US7100233B2 (en) 2003-05-27 2006-09-05 Spx Dock Products, Inc. Vertically-storing dock leveler apparatus and method
US20060156494A1 (en) * 2003-05-27 2006-07-20 Spx Dock Products, Inc. Vertically-storing dock leveler apparatus and method
US20050028305A1 (en) * 2003-05-27 2005-02-10 Spx Corporation Vertically-storing dock leveler apparatus and method
US7657957B2 (en) 2003-05-27 2010-02-09 4Front Engineered Solutions, Inc. Vertically-storing dock leveler apparatus and method
US20040237223A1 (en) * 2003-05-27 2004-12-02 United Dominion Industries, Inc. Vertically-storing dock leveler apparatus and method
US20050160540A1 (en) * 2003-05-27 2005-07-28 Spx Corporation Vertically-storing dock leveler apparatus and method
US20050172426A1 (en) * 2003-05-27 2005-08-11 Alexander James C. Vertically-storing dock leveler apparatus and method
US6951041B2 (en) 2003-05-27 2005-10-04 Spx Corporation Vertically-storing dock leveler apparatus and method
US7353558B2 (en) 2003-05-27 2008-04-08 4Front Engineered Solutions, Inc. Vertically-storing dock leveler apparatus and method
US20070226923A1 (en) * 2003-05-27 2007-10-04 4Front Engineered Solutions, Inc. Vertically-storing dock leveler apparatus and method
US7043790B2 (en) 2003-05-27 2006-05-16 Spx Dock Products, Inc. Vertically-storing dock leveler apparatus and method
US20050011021A1 (en) * 2003-05-27 2005-01-20 Alexander James C. Vertically-storing dock leveler apparatus and method
US20060156493A1 (en) * 2003-05-27 2006-07-20 Spx Dock Products, Inc. Vertically-storing dock leveler apparatus and method
US20050015900A1 (en) * 2003-05-27 2005-01-27 Alexander James C. Vertically-storing dock leveler apparatus and method
US20050011020A1 (en) * 2003-05-27 2005-01-20 Spx Corporation Vertically-storing dock leveler apparatus and method
US7131160B2 (en) 2003-05-27 2006-11-07 Spx Dock Products Inc. Vertically-storing dock leveler apparatus and method
US7213286B2 (en) 2003-05-27 2007-05-08 4Front Engineered Solutions, Inc. Vertically-storing dock leveler apparatus and method
US7162761B2 (en) 2003-05-27 2007-01-16 4Front Engineered Solutions, Inc. Vertically-storing dock leveler apparatus and method
US20070017044A1 (en) * 2003-05-27 2007-01-25 Spx Dock Products, Inc. Vertically-storing dock leveler apparatus and method
US7017220B2 (en) 2003-09-22 2006-03-28 Spx Corporation Spring counterbalance method and apparatus for variably biasing a dock leveler
US20050060821A1 (en) * 2003-09-22 2005-03-24 United Dominion Industries, Inc. Spring counterbalance method and apparatus for variably biasing a dock leveler
US7134159B2 (en) 2004-01-13 2006-11-14 Rite-Hite Holding Corporation Stump-out apparatus for a dock leveler
US20050150065A1 (en) * 2004-01-13 2005-07-14 Timothy Muhl Stump-out apparatus for a dock leveler
US7032267B2 (en) 2004-05-11 2006-04-25 Rite-Hite Holding Corporation Dock leveler with combination safety leg and lip deflector
EP4292964A1 (en) * 2022-06-13 2023-12-20 Hörmann Alkmaar BV Loading platform

Also Published As

Publication number Publication date
CA919359A (en) 1973-01-23
GB1229614A (es) 1971-04-28
GB1229613A (es) 1971-04-28

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