Safety latch for a dump body

Safety latch includes an active member having a support; a thrust pin actuator with a movable thrust pin actuator element movable to and fro along an axis; a thrust pin having a proximate end attachable to the movable thrust pin actuator element such that the thrust pin can be moved to and fro along the axis with movement of the movable thrust pin actuator element, and a distal end; and a biasing element to bias the thrust pin in an extended position. Passive member includes a catch with a thrust pin receiving hole. When assembled, and the movable thrust pin actuator element is slid to and fro, at least the distal end of the thrust pin can penetrate into or be withdrawn from the thrust pin receiving hole to close or open the safety latch. It can be attached to a dump body, say, as part of a dump vehicle.

FIELD AND PURVIEW OF THE INVENTION

This concerns a safety latch for a dump body having a dump gate; a dump body having the dump gate and the safety latch; and a dump vehicle including the dump body having the dump gate and the safety latch. The safety latch can be fluid-operated. The fluid may be a gas, for example, air, and the dump vehicle may be a dump trailer, for example, an end dump trailer.

BACKGROUND TO THE INVENTION

Dump vehicles such as motorized dump trucks and non-motorized, hauled dump trailers come in various forms. They typically include a dump body for containing a load—for example, a solid sample in discrete pieces or a particulate such as soil, gravel, or construction waste, or foodstuffs such as grain, fruit or vegetables, say, sugar beets, and so forth—and a dump body supporting member, which would include a frame, wheels, and so forth. The dump body of concern includes, in addition to bottom structure for supporting and containing thereabove the load, vertical structure for restraining and containing the load laterally. Part of that vertical structure is a dump gate, which opens and closes in a pivoting motion, typically with a pivot at the top of the gate. The dump gate must be secured in its closed position for transport of the load, and released to open it to dump the load.

As in the case of an end dump trailer, the dump gate pivots at its top and is secured in the closed position by primary latches, usually a pair of dog or hook type latches positioned to grasp a pin or other protuberance near the lowermost portion on opposite sides of the dump gate, here, a tailgate, and draw the tailgate into contact with adjacent side panel vertical structure to close the dump body. Current practice requires safety latches in addition to and above the primary latches. Industry wide, these are manually operated wing-lock, also known as turnbuckle, safety latches. The safety latches function to keep the tailgate closed, not relying on the primary latches alone, and better keep the contents of the dump trailer from unintentionally spilling, noting that spills on roadways, in addition to engendering loss of part of or the entire load, can result in fines and possible injury to motorists and damage to their vehicles. The use of the safety latches also prevents excessive wear on the primary latches.

Although typically the primary latches are pneumatically operated, a designated operator, typically the driver, must physically, manually operate the wing-lock or turnbuckle safety latches. This is to be done under all conditions, including in heat or cold; in wind, rain, sleet or snow; with snow, ice, mud or debris on the ground; and whether the driver feels up to it or not.

Drivers fail in this duty, however, at times not utilizing some or all of the wing-lock or turnbuckle safety latches. Not using safety latches can quickly draw the attention of authorities, who are rightfully on the lookout for such violations. Moreover, some drivers use only the driver's side wing-locks in order to partially comply with laws or regulations, and to avoid circling the entire trailer during each dump cycle. If that happens, with only one wing-lock engaged or with the one that is not latched falling into a partially latched position, when dumping, the tailgate is held on one side and opens first on the free side, which causes twisting of the gate and destruction of the wing-lock and other components. In addition, damage to equipment can result when drivers do not get to the turnbuckle safety latches in time to release them before a load is dumped, in which case the tailgate can burst open as material piles up against it as the dump body is tilted, thus destroying tailgates, hinges, and turnbuckles.

The following references, which are incorporated herein by reference, may be of interest:

U.S. Pat. No. 1,586,808 to Hug. This discloses a dumping truck, which has a simple latch system to release a bottom opening tailgate. It has a complicated dumping mechanism, with an automatic tailgate opener. No secondary safety latch is present.

U.S. Pat. No. 2,210,286 to Fitch. This discloses an end gate latch, which has a pair of horizontally moveable, manual latches to secure a bottom opening end gate. It has a fixed rear wall, with a gate added as a grain door. Its manual open-close operation requires being in close proximity to a rapidly moving gate, and there is pressure from the contents. No secondary safety latch is present.

U.S. Pat. No. 2,675,268 to Hutchinson. This discloses endgate control for truck bodies, which has a simple moveable hook to hold a bottom opening tailgate closed. It has manual, cab-operated factory bottom latches, which, from the link rods 32 rearward, generally are the same as those used in current systems. No secondary safety latch is present.

U.S. Pat. No. 3,325,216 to Boeck. This discloses automatic tail gates for dump trucks and the like, which has fluid-pressure piston and cylinder actuated movement of a gate and bottom and side latches. It has hydraulically operated unlatching and lift of its tailgate, with the first 2-3 inches of cylinder extension unlatching four latch mechanisms. Two upper points act as secondary safety latches (wing-locks). It does not require the driver to leave the cab of the truck.

U.S. Pat. No. 4,032,192 to Jensen. This discloses a latching mechanism for a rear gate of a dump vehicle with an automatic tilt release, which has a pair of moveable side catches that engage a horizontal rod positioned mid-way between the top and bottom of a bottom opening rear gate. It opens the tailgate with box tilt (lift) and replaces factory latches at the bottom of the gate. No secondary safety latch is present.

U.S. Pat. No. 4,691,956 to Hodge. This discloses a counterbalanced tailgate for dump boxes, which has a spring-containing lower horizontally moveable lower locking pin for a bottom opening tailgate. It represents a way of turning a latch into a hinge for a two-way gate. No secondary safety latch is present.

U.S. Pat. No. 5,413,402 to Flerchinger et al. This discloses a sequenced tailgate lock, which includes two or more fluid-operated piston and cylinder locking assemblies, one of more of which is visible to an operator. Actuation is sequenced. It represents hydraulic replacement of factory latches, with packer boxes requiring strong hinges and locks, and has all cab operation.

U.S. Pat. No. 6,135,565 to Bachelor. This discloses a rotary tailgate latch operating system, which has lower horizontally moveable lower locking pins for a bottom opening tailgate. It represents employment of rotary action for activating factory latches. No secondary safety latch is present.

U.S. Pat. No. 6,382,731 B1 to Slutz et al. This discloses a load hauling vehicle with sidewall raising and lowering mechanism, which can be dumped to the rear or side. It pertains to side loader function, with tailgate latch 38 and latch 42 known factory latches. No secondary safety latch is present.

U.S. Pat. No. 6,764,130 B1 to Hull. This discloses a multi-position tailgate for dump trailers, which has top or bottom pivoting opening capability through horizontally extending pins engaged by side latches. It represents an all-manual three-way tailgate.

U.S. Pat. No. 8,944,484 B2 to Kibler et al. This discloses a pressurized locking assembly for a side-swing tailgate and a tailgate incorporating the same, which includes a manual safety latch of the turnbuckle variety. It represents a two-way tailgate with its safety latch 112 an original wing-lock style secondary safety latch. A pneumatic or hydraulic cylinder 82 operates a top hinge/latch of its locking assembly 35 for barn door operation.

U.S. Pat. No. 9,039,097 B2 to Petzitillo, Jr. et al. This discloses an apparatus and method for remotely locking a container, which is adapted for transport on one or more vehicles such as an intermodal container, which includes bottom and mid-level side pins horizontally extending to be engaged by moving hydraulically actuated hook latches. Watertight intermodal containers require more point of closure to assure a strong door seal. The container doors must be operable in any position, on a truck, on the ground, and so forth. Actuation is hydraulic.

U.S. Pat. No. 10,266,092 B2 to Gardner. This discloses a low center of gravity dump trailer with a hydraulically latched cover. It has manual rear lower primary closure and mid-level safety latches for a bottom-opening rear gate. It pertains to top cover open-close operation, with original wing-lock style secondary safety latches employed on its tailgate (FIG. 3).

It would be desirable to ameliorate if not overcome at least one of the drawbacks and problems in the art, to include as aforesaid, particularly as concerns the known safety latches and their operation. It would be desirable to provide the art an alternative, particularly for use with dump vehicles, especially hauled dump trailers, most especially end dump trailers.

A FULL DISCLOSURE OF THE INVENTION

Provided hereby is a safety latch for a dump body, in assembled or in kit form, which comprises the following (A, B):(A) an active member, which includes a support, and the following (A′, B′, C′):(A′) a thrust pin actuator, which has a movable thrust pin actuator element that is able to be moved to and fro along an axis in which motion can ensue through non-manually applied force;(B′) a thrust pin having proximate and distal ends, with the proximate end attachable to the movable thrust pin actuator element such that the thrust pin is able to be moved to and fro along the axis with movement of the movable thrust pin actuator element; and(C′) a biasing element to bias the thrust pin in an extended position; and(B) a passive member, which includes a catch having a thrust pin receiving hole such that—when the active member is assembled, and the movable thrust pin actuator element is slid to and fro—at least the distal end of the thrust pin can penetrate into or be withdrawn from the thrust pin receiving hole so as to close or open the safety latch.

The present safety latch can be attached to a dump body having a dump gate to provide a dump body, safety latch combination, which comprises the dump body, which has a bottom structure for supporting and containing a load above it; and vertical structure for restraining and containing the load laterally, a first portion of which includes, as the dump gate, an openable and closable dump gate pivotable about a pivot and securable in a closed position by at least one primary latch spaced apart from the pivot, and a second portion of which is able to be rendered stationary with respect to dump gate; and the safety latch attached to the dump body, with at least one active member assembled and attached to openable and closable dump gate, and, for each active member, the passive member attached to the portion of the vertical structure rendered stationary with respect to the dump gate. The present dump body, safety latch combination can be attached to a dump body supporting member, which would include a frame, wheels, and so forth, to provide a dump vehicle, safety latch combination.

The invention is useful in goods transport.

By the invention, the art is advanced in kind, and at least one of the problems in the art is ameliorated if not solved. The art is provided an alternative, particularly for use with dump vehicles, especially hauled dump trailers, most especially end dump trailers. More particularly, a one-step dumping procedure is provided, eliminating the need for the driver to be in the area of a dumping trailer, especially in the rear with end dump trailers. Thus, driver safety and efficiency are increased dramatically, and the chance of damage to equipment is minimized. The safety latch can be fluid-operated. With air as an exemplary fluid, and an end dump trailer as an exemplary dump vehicle, the air-operated safety latches can operate simultaneously, using a factory switch setup with the primary tailgate latches, which are found at the bottom of nearly all end dump trailers. A delay system can be employed to release the air-operated safety latches first, and then to release the primary latches to operate (open), thus allowing the contents of the trailer (load) to be dumped with the driver safely away from danger. Thus, for example, air-operated safety latches operate without additional manual controls installed; the existing tailgate release switch is flipped, releasing the safety latches, which can operate at a first value, say, an approximately 40-psi value, owing to the biasing element, say, compression springs; pressure in the system must reach a second value higher than the first value, say, an approximately 70-psi value, before the primary gate latches release; this provides a reserve to be attained, say, an extra 30-psi or so reserve, for releasing the safety latches in case the driver encounters a situation that would require delay or cancelation of dumping of the load or for any other reason. The air-operated safety latches can be provided with a visual signal, for example, high visibility flags such as of metal or engineering plastic that are raised stand out and are visible from the cab of the tractor, so as to notify that the safety latches are engaged. These flags can also alert the driver when the safety latches are not engaged by being down and less visible from the cab of the tractor. The invention is economical to manufacture and operate, and provides excellent cost benefits. Drivers really like it.

Numerous further advantages attend the invention.

FURTHER ILLUSTRATIVE DETAIL

The invention can be further understood by the detail set forth below. As with the foregoing, the following, which also may be read in view of the drawings, is to be taken in an illustrative and not necessarily limiting sense.

With reference to the drawings, the present safety latch100is for mounting on dump body1. The safety latch100, which may be considered a secondary latch, i.e, a “secondary safety latch,” includes active member10and passive member50. The active and passive members10,50may be provided separately or together assembled and/or mounted as on the dump body1or as a kit for assembly and mounting on the dump body1following receipt of the kit. Component parts may be made by known methods including machining and so forth.

The dump body1has dump gate2, for example, with manual override lever tool end receiving holes2H provided suitably therein, and bottom structure3for supporting and containing a LOAD above the bottom structure3, with vertical structure4restraining and containing the LOAD laterally. A first portion of the vertical structure4would include, as the dump gate2, an openable and closable dump gate pivotable about pivot5, for example, at the top of the dump gate2, and securable in a closed position by at least one primary latch6, most often two, such as a pair of dog or hook type latches known in the art, for example, operated by fluid-activation, typically by pressurized air, which is spaced apart from the pivot5, for example, as in an end dump trailer, opposing one another near the lowest and outermost parts of the dump gate2. A second portion of the vertical structure4is able to be rendered stationary with respect to the dump gate2, for example, being permanently configured as side and front walls of an end dump trailer. The dump gate2, for example, designated the tailgate in an end dump body, is drawn into contact with adjacent side panel vertical structure4to close the dump body1, for example, permanently secured side wall vertical structure at the rear of the dump body1. The dump body1is able to be mounted on dump body supporting member8, which can include a frame, wheels, and so forth, to provide dump vehicle9. The dump vehicle9may be motive powered as in the case of dump trucks, or non-motive powered as in the case of dump trailers, for example, end dump trailers, which may be configured as lead and pup trailers in a train.

The active member10includes support11. It also includes thrust pin actuator20, thrust pin30, and biasing element40.

The support11may take any suitable form and be made of any suitable material(s), for example, in a form of housing11′ made of structural metal(s) such as aluminum and/or steel. The housing11′ provides channel12that is open for ready access for or to the thrust pin actuator20, thrust pin30, and biasing element40for assembly, or, after assembly, for manipulation, repair or replacement. In the channel12can be interior mount13, say, of aluminum, with the channel12bounded by first end14, say, of aluminum, and opposing second end15, say, of aluminum. The channel12may be ordered with first space14S and second space15S, with the first space14S going from the interior mount13to the first end14, and the second space15S going from the interior mount13to the second end15. When the active member10is oriented for mounting or mounted on the dump body1, first elongate member16may serve as a bottom portion of the housing11′; second elongate member17may oppose the first elongate member16and serve as a top portion; and third elongate member18may reside between the first and second elongate members16,17and serve as a base, which may face rearward so as to define a rear portion. The first and second elongate members16,17may be considered to be legs, with the third elongate member18considered to be a face; and each of these members16,17,18may, for example, be of aluminum, and be joined from separate pieces or made, say, extruded, as one piece. The interior mount13, first end14, opposing second end15, and first, second and third elongate members16,17,18are suitably assembled and joined such as by welding or another provision to make the housing11′. Hole(s)19may be provided. For example, holes19may be provided to receive component or auxiliary parts or fasteners, or be threaded to receive threaded portions of bolts or screws; air hose hole19A and manual override access opening19B, say, in a form of a J- or L-shaped slot, an arm of which may be guarded by pivoting override access opening cover19C, may be provided in the support11and housing11′; slot19S can be provided in the first end14for attachment of a fixed end of an air head cylinder actuator, for example, a substantially fluid-tight container23, and/or in the second end15to accommodate a wedge end34W; and a suitable hole19may be equipped with grease zerk19Z. In general, the support10may be of any suitable size and shape. For example, when configured as the housing11′, it may be in a form of an elongate rectangular box, with an overall length about from twelve to twenty-eight to include sixteen to twenty-four inches, and an overall height and width about from two to five inches to include about from three to four inches. Thicknesses of the interior mount13, first end14, opposing second end15, and first, second and third elongate members16,17,18, for example, may be about from ⅛ of an inch to 1½ inches depending on materials selected and other components provided, for example, grease zerks19Z, or not, with the interior mount13, first end14, and opposing second end15typically more thick, say, advantageously about from ½ of an inch to one inch, than the first, second and third elongate members16,17,18, which may be, say, advantageously about from 3/16 of an inch to ⅜ of an inch.

The thrust pin actuator20is supported by and attachable to the support11, and has movable thrust pin actuator element21—which, in one embodiment of preferred fluid-actuated operation, can include piston21P with piston rod21R—and is able to be moved to and fro along axis22in which motion can ensue. The piston rod21R may have tapered or preferably threaded distal end21RT. Force for normal actuation of the thrust pin actuator20and operation of the active element10is applied non-manually. The thrust pin actuator20can be in a form of a thrust pin actuator assembly as in the one embodiment alluded to above, which can include the substantially fluid-tight container23, which has hollow volume24, and interior wall(s)25spaced apart from and substantially parallel to the axis22; and the movable thrust pin actuator element21can be the piston21P, which has lateral boundaries that conform closely to the interior wall(s)25such that, when the piston21P is positioned in the hollow volume24, the piston21P is able to be slid to and fro along the direction of the axis22along which motion can ensue under influence of fluid as the non-manually applied force when the fluid is provided into or withdrawn from the hollow volume24at sufficient pressure to cause the piston21P to slide. Actuation source conduit29, for example, pressurized fluid line, say, pressurized air in a pneumatic system, provides the necessary power or force to actuate the thrust pin actuator20. In addition to or in lieu of fluid-actuation and operation, actuation and operation may be provided by other means or devices, for instance, magnetic and/or electromagnetic force as, for example, from a solenoid that activates a movable thrust pin actuator element shaft; an electric motor, a fuel-powered engine, or fluid pressure to actuate a screw shaft constituting a movable thrust pin actuator element shaft, or a rack constituting a movable thrust pin actuator element shaft in combination with a pinion or worm gear; and so forth. Advantageously, the actuation force is provided from linear to and fro motion. Beneficially, the actuation and operation is pneumatic. As such, the thrust pin actuator20can be a commercial pneumatic piston-and-cylinder device such as a Model No. 703DPX pneumatic device from Bimba Mfg. Attachment to the support11or housing11′ can be by using the slot19S in the first end14and a socket head cap screw.

The thrust pin30, for example, of mild steel, may be one piece or in multiple pieces, for example, two, in which case connecting end30T threaded, for example, with male threads. The thrust pin30has proximate end31, which is attachable to the movable thrust pin actuator element21such that the thrust pin30is able to be moved to and fro in the direction of the axis22with movement of the movable thrust pin actuator element21. Fixing feature32, for example, centered, blind hole31H such as from drilling may be provided in conjunction with threads32T, for example, female threads, in and on the proximate end31so that the proximate end31of the thrust pin30can be fixed to a correspondingly threaded distal end21RT on the piston rod21R. The threads32T may be provided by fixing, for instance, epoxy gluing or preferably welding, a nut with any from a number of thread sizes and pitches, for example, a National Standard Fine (NSF), say, a ¾-inch NSF, thread nut or, for example, a matching threaded, shaft-end-of-cylinder nut for highly secure coupling, to a proximate end31having the hole32H. A bolt or rod may be used to align the nut and hole32H before fixation. The thrust pin30also has distal end33, which may have tapered extremity34or wedge34W. The wedge34W may be one piece with the rest of the thrust pin30; be made from two or more pieces, say, two, thrust pin30portion with a wedge34W, but attached by welding to make one integral item, which is preferred; or be attachable in a multi-piece thrust pin, for example, with threads, say, female threads, which mate with the threaded connecting end30T. A wedge34W may be made of any suitable material, for example, a mild steel, say, #A-36, which can provide for ready welding of pieces to one another. Recess35may be provided, which, for example, may be in a form of a shallow circumferential groove about a substantially cylindrical thrust pin such as the thrust pin30, to position collar36having inner face36F and receive set screw(s)37having threads37T in threaded hole(s)37TH to hold the collar36fast to the thrust pin30. The collar36can be provided with shoulder38. Manual opening shaft39, for example, provided with threads39T, may be fixed to the collar36, for example, through fastening in threaded hole39TH. The manual opening shaft39, in conjunction with its operation in the override access opening19B with its override access opening cover19C flipped open to expose the holding portion of the override access opening19B, can be used to open and hold the safety latch100open if there is a power failure. In general, the thrust pin30may be of any suitable size and configuration. For example, the thrust pin30may be in a form of elongate member, for the most part cylindrical, with a length about from eight to sixteen inches, a diameter about from one to two inches before any tapering, say, at the extremity of the distal end33or provision of any recess35, say, roughly midway along its length. As well, the collar36, for example, may be an annular member with an inside diameter or other shape to accommodate insertion of the thrust pin30and outside diameter or other shape about from two to four inches, and thickness suitable for providing the threaded hole(s)37TH and/or39TH, say, excluding an additional shoulder38.

The biasing element40is any contrivance or device that can bias the thrust pin30in an extended position. The biasing element40can be a spring, for example, a compression spring, which may be stopped at one end by the interior mount13and at its opposing end by the collar36on the thrust pin30while having an end whereof residing on the collar shoulder38, and have an about 75-lb. resistance per inch of travel, a resistance that can be overcome to move the thrust pin30, for example, with an about 40-psi air load against a piston21R having sufficient work surface area such as in the thrust pin actuator20exemplar introduced above.

In general, with the thrust pin actuator20, thrust pin30, and biasing element40included within the active element10, one or more of the following may apply: at least part of the thrust pin actuator20assembly resides in the first space14S of the housing11′; the thrust pin30has sufficient length so as to reside at least in part in the second space15S of the housing11′ and have its distal end33pass beyond the second end15of the housing11′; and the biasing element40is attachable to the thrust pin30and the housing11′, and/or interior mount13to bias the thrust pin30in an extended position. For example, with a compression spring as the biasing element, the interior mount13can form a first restraining end, and the collar36can form a second restraining end. The collar36fixed to the thrust pin30may reside in the second space15S. The biasing element40may be another type of spring such as extension and/or torsion spring(s), which may have one part attached to any convenient place on the support11, which may be configured such as the housing11′, and another part attached to the thrust pin30. When the thrust pin actuator is a piston-and-cylinder device as mentioned above including the piston21P in the substantially fluid-tight container23with hollow volume24, the biasing element40, notably when embodied as a spring, may be positioned inside that container23within its hollow volume24on one side of the piston21P and/or the other. For another example, biasing force from an extended biasing element40in a closed safety latch100, particularly when a spring, engages the wedge34W tighter in the passive member50, with vibration, helping to close GAP between the dump gate2and stationary vertical structure4, but the wedge shape provides for easy release. A biasing element40such as a compression spring may engage an inner face of a wedge34W, in lieu of engagement with the corresponding inner face36F of the collar36.

Typically, the active member10is mounted to the dump gate2between the upper pivots5and primary latches6, for example, roughly midway between them. The active member10may be attached to the dump gate2by welding the formed channel housing11′ to the gate2, especially when the gate2and housing11′ are made of the same metal, for example, aluminum or steel, with the third elongate member18serving as the base and abutting the gate2. Thus, the components20,30,40inside the housing11′ can be exposed or uncovered for service. In cases of dissimilar metals that cannot be welded easily, for example, steel and aluminum, a weldable spacer block made of an appropriate one of the metals and, say, having fastener holes, may be provided for welding and mechanically fastening the active member10akin to the case with passive member attachment as set forth below. Suitable mechanical fasteners alone may suffice.

The passive member50includes catch51, which may be in a form of plate52, for example, of steel, say, mild steel, having thrust pin receiving hole53, which may be of any suitable size and shape, for example, cylindrical or in a form of a slot. When the active member10is assembled, and the movable thrust pin actuator element21is slid to and fro to move the thrust pin30to and fro, at least the distal end33of the thrust pin30penetrates into or is withdrawn from the thrust pin receiving hole53to close or open the safety latch100. The thrust pin receiving hole53, which may be provided from insertion into catch plate hole53′ a thrust pin receiving hole bushing53B, may have inside bevel54on its thrust pin entry side for easier receipt of the thrust pin30with a tapered extremity34. The plate52may have bracing55, for example, of steel, say, mild steel, attached, say, about its periphery, which may be perpendicular, in general, to the plane of the plate52. End bracing55E, for example, of steel, say, mild steel, can be attached to an end of the plate52opposing the thrust pin receiving hole53. Angled, striker plate ramp56, for example, of steel, say, mild steel, can be attached to the catch51, for example, near the thrust pin receiving hole53, to force partial retraction of the thrust pin30sufficient to allow enough of the distal end33of the thrust pin30to be retracted and pass into to enter the thrust pin receiving hole53and allow for shutting and securing the dump gate2if the force necessary to retract the thrust pin30fails, for example, with failure of fluid pressure or other required power. The catch51can be provided with mounting holes57and/or mounting spacer block58, for example, of aluminum, that may be provided with threaded holes58TH to align with the mounting holes57and receive mounting bolts, and be welded at a suitable place to the second portion of the vertical structure4of the dump body1able to be rendered stationary with respect to the dump gate2, for example, a permanently configured as side wall of the dump body1. Signal mount receiving slot tabs59can be attached with alignment to the thrust pin receiving hole53. Attachment of components of the passive member59can be by any suitable manner, for instance, welding, screwing, riveting and/or gluing. Welding is a preferred method. In general, the passive member50may be of any suitable size or configuration. For example, the passive member50may include a catch51in elongate form, with catch plate52about from twelve to twenty inches long, two to four or five inches high, and ⅛ of an inch to ⅜ of an inch in thickness. Any bracing55,55E, angled striker plate ramp56and/or spacer block58may account for extra length, height and/or thickness or width.

Signaling device60, for example, a pivoting signal flag made of metal panel, beneficially is provided. Such a signaling device60may operate mechanically, based on motion and position of the distal end33of the thrust pin30in relation to the thrust pin receiving hole53of the passive member50. An “up” or “down” position of such a signaling device amply provides a highly reliable, highly visible signal for the driver. For example, a locked or closed safety latch100can be signaled by an “up” position provided when the distal end33is extended through the thrust pin receiving hole53and pushes a lower portion of a flag outwardly to pivot a flag60upward, with an unlocked or open safety latch100signaled by the “down” position of a flag60pivoted back into its lower position by force of gravity when the distal end is retracted out of the thrust pin receiving hole and away from contact with the lower portion of the flag. The pivoting flags can have any suitable size and shape, and may be colored brightly, for example, with different sizes, shapes and/or colors for lead trailers than for following pup trailers, which can assist the driver in monitoring his equipment. For example, the signal flag60may be about from three to six inches laterally and perpendicular to lateral, with, as in the case of a train or a dump truck towing a trailer, a smaller flag for a lead trailer and a larger flag for a following pup trailer or the smaller flag for the truck and the larger flag for the trailer; and have a roughly planar, triangular shape with pivot receiving hole61near one corner, primary visual area62in a main portion, and have depending tooth63for contact with the tapered extremity34of the distal end33of the thrust rod30so that the flag60may be pivoted about a pivot received in the receiving hole61; and be colored a bright yellow or orange for added left and right or possible front and rear identification. Left and right side signaling devices60may be provided.

Cover70can be provided. The cover70can include main body71, first side72, and second side73, which can be made of suitable material(s) such as structural metal(s), for example, aluminum, say, 11-guage diamond-patterned aluminum plate. The main body71may be formed of one piece and bent or creased to provide a main body that is angled and have a cut out or trimmed portion near a top corner for contouring for a tight fit on a gate2, and the first and second sides72,73may be provided in triangular forms, for example, with the first side72larger than the second side73. The first and second sides72,73may be initially separate from the main body and attached subsequently, for example, by welding, so that the cover70can exclude debris effectively. Mounting holes74to accommodate attaching the cover70to the housing11′ with suitable fasteners such as bolts or screws may be provided in the main body71. Side hole75, for instance, about from ⅜ of an inch to ¾ of an inch in diameter, may be provided, say, in the first side72, to provide for air-line entry. Tool hole76, for instance about from ¾ of an inch to 1½ inches in diameter, may be provided also in the first side72.

Manual override lever tool80may be provided. The manual override lever tool80may be in a form of a rod made with a suitable material such as a structural metal, for example, an elongate cylinder about from eighteen to thirty inches long by about from ½-inch to ¾-inch diameter aluminum, which may have circumferential end notch81defining end knob82, which can be placed in the manual override lever tool end hole2H to form a pivot while a spaced apart portion of the manual override lever tool is brought to bear against the manual opening shaft39to manually retract the thrust pin30against the force of the biasing element40into an open position, which may be secured in part of a J- or L-shaped the manual override access opening19B. Manual override lever tool grip83, for example, a compression fitting, say, an annular compression fitting such as a Truck-Lite ¾-inch compression fitting #50842 made from plastic, may be placed into the tool hole76for insertion and storage of the manual override lever tool80. (A second manual override lever tool80may be stored elsewhere, for instance, in the cab of a dump truck or truck tractor for pulling dump trailer(s) equipped with the safety latch100.)

The safety latch100can be attached to the dump body8having the dump gate2to provide dump body, safety latch combination100′. The dump body, safety latch combination100′ can be attached to a dump body supporting member, which could include a frame, wheels, and so forth, to provide dump vehicle, safety latch combination100″.

The necessary power or force delivered through the actuation source conduit29to actuate the thrust pin actuator20and operate the safety latch100can be self-contained within a safety latch system or come from a source other than a dump vehicle9to which the safety latch100is attached. Advantageously, however, the necessary power of force is obtained from outside the safety latch system, for example, coming from a source already present on a dump vehicle9to which the safety latch100is attached, for example, from a pressurized fluid line, say, pressurized air in a pneumatic system, already present on or with the dump vehicle9, into which the actuation source conduit29taps. An activation switch already existing on a frame of a dump vehicle9, for example, may be employed. Activation switching may be moved to the cab of a tractor pulling a trailer or a truck equipped with the dump body8to make the same either a non-motorized or a motorized dump vehicle9, respectively, with dump control in the cab.

To recapitulate, for example, air pressure to each of the two safety latches100operates each of their pneumatic cylinder thrust pin actuators20, one left and the other right, which are secured to a swinging tailgate2that are usually extended and held in the extended position for latching or locking by a coil compression spring as the biasing element40delivering about seventy-five pounds per inch of travel. Pistons21P as the movable thrust pin actuator elements21have sufficient surface area so that air pressure, say, at about forty pounds per square inch, can overcome the force of the biasing element40. The air pressure introduced into the thrust pin actuators20retracts each piston21P in its substantially fluid-tight container23having hollow volume24, and cylindrical interior wall(s)25, each piston connectable to a thrust pin30, and compresses the coil compression spring biasing element40to retract the thrust pin so that its distal end33is pulled out sufficiently clear of the thrust pin receiving hole53of the catch51securely attached to exterior surfaces of nonmoving vertical sides4of the dump body1such as the sides of end dump trailers to unlatch or open the safety latch100. This allows the tailgate2to open when the dump body1is pivotally raised so that the LOAD can be emptied. In the event that there is an air supply failure, the angled, striker plate ramps56are provided so that the actuator pin30can be withdrawn enough against the force of the biasing element40so that its distal end33can enter the thrust pin receiving hole53as the driver eases forward, sliding the tailgate2over the pile of emptied LOAD and slamming shut without debilitating metal-on-metal contact of an extended thrust pin30against a catch plate52or bracing55.

CONCLUSION TO THE INVENTION

The present invention is thus provided. Various feature(s), part(s), step(s), subcombination(s) and/or combination(s) may be employed with or without reference to other feature(s), part(s), step(s), subcombination(s) and/or combination(s) in the practice of the invention, and numerous adaptations and modifications can be effected within its spirit, the literal claim scope of which is particularly pointed out as follows: