Aerial grapple apparatus and method for handling loose material

A grapple, designed to grab, ferry, and dump loads of loose material such as mulch, comprising left and right frame members and finger assemblies with specially adapted curved fingers. Load arms connect the grapple to a supporting means, typically a helicopter, and also serve as anchors for finger cables and connecting arms cooperating with the finger assemblies to open and close the grapple. The method of grabbing prominently features using the shape of the fingers and the weight of the grapple and load to penetrate into and under the load. A latching mechanism cooperating with the connecting arms ensures stable ferrying until the remote operator, generally the helicopter pilot, activates an electrical control switch to release the latch and dump the load.

BACKGROUND OF THE INVENTION

The invention relates to a grapple apparatus for grasping, lifting, and releasing loads, particularly adapted for handling loose material such as hay or mulch, and the method of operation of the apparatus.

Grappling devices are common in a number of agricultural and industrial fields and there is a steady demand for improved material-handling apparatus and methods. One fairly recent application for which a well adapted grapple would be useful is the practice of helimulching, i.e. spreading mulch and related materials over large land areas by dropping the material from a helicopter at an altitude suitable to gain the dispersal required. While this is not the only intended application of the present invention, it points out several directions which, individually or in combination, could present goals for improvement over prior art grapples. Specifically, a device used for helimulching must be efficient in its use of people, time, and weight, as many aerial grappling applications take place in wilderness areas where ground-based options are not safe or practical to pursue, and the cost of helicopter time, fuel, and labor is high. An effective grapple for this purpose must also be robust in its ability to manage shock loading, to which helicopters are especially sensitive.

There is no prior art device known to the inventors that combines all of the above strengths. However, an inventory of a few selected prior art grapples will identify the problems traditionally encountered in the development of related machines.

U.S. Pat. No. 52,134, issued Jan. 23, 1866 to Buckman, discloses the semi-automatic operation of a horse hay-fork having fork tines or fingers at the lower ends of its frame halves which are guided, through a combination of levers and hinges, to an essentially horizontal position when retaining a load and an essentially vertical position when releasing a load. The release control requires only the pulling of a rope. However, the rope must be pulled manually, making such a grapple ineffective for working at altitude or in heavily sloped and wooded areas where human access is limited.

U.S. Pat. No. 1,462,787, issued Dec. 19, 1921 to Degendorfer, offers an example of an agricultural fork which explicitly eliminates the need for direct manual intervention with the machine itself; the machine can be controlled remotely by a derrick operator. In this machine the weight of the load even provides some advantage in that it exerts forces on the machine causing it to retain its closed position more firmly. However, the operation still requires multiple cables and therefore some operator skill, and the machine is still confined to ground-based operation.

U.S. Pat. No. 2,815,242, issued Dec. 3, 1957 to Kenyon, discloses a tongs-like device also featuring the intelligent use of weight to help grasp a load, but the weight in this case takes the form of a counterweight, which would dramatically reduce efficiency in a force- and fuel-critical helicopter-towed operation.

Another effective ground-based use of weight is found in U.S. Pat. No. 4,943,099, issued Jul. 24, 1990 to Gabriel, for a magnetic cargo hook that automatically releases when it hits the ground, due to its weight being transferred from a load cable to the ground. However, for aerial operations, the ground-based release would severely limit available altitude and likely applications.

More recently, U.S. Pat. No. 5,653,489, issued Aug. 5, 1997 to present co-inventor Fandrich, provides the best prior art reference as it takes several steps in the right direction while still leaving ample room for improvement. The grapple disclosed in that patent is specifically designed for aerial operation and as such is both lightweight and strong, so that helicopter payload can be maximized. The grapple features shock damping devices to reduce operator risk and fingers capable of squeezing tightly and releasing slowly. However, this earlier grapple is best suited for certain types of materials, particularly for logs, as they are able to be grasped firmly when sufficient clamping force is available. Other materials, especially loose materials such as mulch, do not submit as readily to this type of grabbing action. Minimally, a series of improvements to the existing machine would be required, none of which would be obvious at first.

BRIEF SUMMARY OF THE INVENTION

The apparatus and method of this disclosure provide substantial improvements to the aerial grappling of loose materials, including a method featuring substantially automatic operation.

A grapple apparatus according to the main embodiment of the invention comprises right and left main frame members hinged together at a main hinge, and right and left finger assemblies each hinged to a respective frame member at a respective finger hinge. Each finger assembly comprises a finger frame and plural fingers mounted on the frame. The fingers are designed to penetrate a pile of loose material such as mulch. The finger assemblies rotate relative to the frame members in order to grab and dump loads, and their rotation is limited by inward and outward stops cooperating with the main frame.

The grapple further comprises right and left load arms hinged together at the main hinge. The ends of the load arms are also connected to load cables which in turn are connected by a main cable to a supporting means such as a helicopter. Connecting arms connect each load arm to the finger assembly on the opposite side of the grapple, and finger cables connect each load arm to the finger assembly on the same side of the grapple. The connecting arms therefore assist in holding the grapple closed, while the finger cables assist in holding the grapple open.

Latches on the load arms control the connection between the connecting arms and load arms. The latches are normally engaged but can be disengaged by means of a solenoid connected by power wires to a control switch used by the operator, typically the pilot of the towing helicopter.

The drawings and detailed description following further disclose the main embodiment of the apparatus and its method of operation, followed by a series of options and alternatives, as well as an additional embodiment of the apparatus and its related method of operation, all of which are intended to enable a person having ordinary skill in the art to make and use the invention without limiting the scope thereof to the embodiments particularly described and illustrated herein.

The drawings and specification employ the following reference numerals. Paired reference numerals (e.g. “21, 121”) indicate functionally identical pairs of elements, one appearing in each of the two halves of the grapple apparatus. Such paired elements will typically be mirror images of each other.

The following reference numerals first appear in the description of the main embodiment, which corresponds toFIGS. 1 through 4:

The following reference numerals first appear in the description of the options and alternatives, which corresponds toFIGS. 5 through 8:

The following reference numerals first appear in the description of the additional embodiment, which corresponds toFIG. 9:

DETAILED DESCRIPTION OF THE INVENTION

The grapple apparatus16described herein comprises right and left halves connected at a main hinge20. When description is given for only one half of the grapple, and additional reference numerals are given in parentheses, it is to be understood that the opposite half of the grapple acts simultaneously with the half described and in a similar way thereto, generally as a mirror image thereof. This practice shall be employed selectively in order to optimize clarity and, where possible, simplicity.

Description of the Main Embodiment

As seen inFIG. 1, a grapple apparatus16according to the invention comprises right and left frame assemblies21and121having inner portions, here designated as right and left main frame members22and122respectively, hinged together at main hinge20. The frame assemblies21and121also have outer portions, here designated as right and left finger assemblies40and140respectively, joined to respective main frame members22and122by right and left finger hinges26and126respectively.

The main frame members22and122are also bridged by a main stop assembly25which cooperates with main frame members22and122to limit outward rotational movement of frame assemblies21and121with respect to the main hinge20. Main stop assembly25comprises main frame limit rod28, which is attached to main frame22, and one or more main stop holes33into which main stop pin29(shown inFIG. 7) may be placed to fix an outer limit to the rotation of frame assemblies21and121about main hinge20and thereby limit the extent to which the grapple is able to open. Similarly, main stop assembly25may further comprise one or more frame inward stop holes39into which frame inward stop pin38(shown inFIG. 7) may be placed to fix an inner limit to the rotation of frame assemblies21and121about main hinge20and thereby limit the extent to which the grapple is able to close.

Finger assembly40(140) comprises a finger frame43(143) to which plural fingers46(146) are fastened, said fingers having inner portions fastened to finger frame43(143) at finger mounts44(144) and outer portions, here designated as finger tips45(145), designed to penetrate a pile of loose material (not shown) such as, but not limited to, mulch.

Finger frame43(143) is hinged to rotate with respect to main frame22(122) about finger hinge26(126), said rotation being limited by finger open limit stop47(147) and finger closed limit stop48(148) which are fastened to main frame22(122). Finger open limit stop47(147) is adapted to contact finger assembly40(140) to limit its outward rotation relative to main frame22(122). Finger closed limit stop48(148) is adapted to contact finger assembly40(140) to limit its inward rotation relative to main frame22(122).

When the grapple is fully closed, as seen inFIG. 1, fingers46(146) extend in a generally horizontal direction. When the grapple is fully open, as seen inFIG. 2, fingers46(146) extend in a generally vertical direction.

Returning toFIG. 1, the grapple further comprises right and left load arms34and134having inner portions hinged together at the main hinge20, and outer portions cooperating with right and left load cables36and136respectively. Load cables36and136are connected at load cable mount50(shown inFIG. 4) to main cable54(shown inFIG. 4) which is typically suspended from a helicopter.

Load arms34and134are disposed symmetrically on opposite sides of a vertical plane of symmetry passing through main hinge20and parallel to load arms34and134. Likewise, right and left connecting arms64and164, as well as right and left latches70and170, are disposed symmetrically on opposite sides of the same vertical plane.

Connecting arms64and164are connected at their respective upper termini to load arms34and134, respectively. The lower terminus of right connecting arm64is connected to left finger assembly140, and the lower terminus of left connecting arm164is connected to right finger assembly40.

Connecting arm64(164) comprises pull arm upper lever66(166), pull arm lower lever68(168), pull arm rod55(155), and a series of hinges. The upper portion of pull arm upper lever66(166) is hinged to load arm34(134) by lever arm hinge65(165). The lower portion of pull arm upper lever66(166) is hinged to the upper portion of pull arm lower lever68(168) by lever hinge67(167). The lower portion of pull arm lower lever68(168) is hinged to the upper portion of pull arm rod55(155) by guide hinge61(161). The lower portion of pull arm rod55(155) is hinged to the upper portion of lower arm mount158(58) by pull arm hinge157(57). The lower portion of lower arm mount158(58) is connected to finger frame143(43).

Right and left guide levers69and169are hinged at their inner portions to main hinge20, about which guide levers69and169rotate. The other end of guide lever69(169) is hinged to pull arm lower lever68(168) and pull arm rod55(155) at guide hinge61(161).

Right and left latches70and170are connected to load arms34and134respectively. Latch70(170) has a latch hook72(172) designed to engage automatically with lever hinge67(167) and to disengage upon operator control. Latch hook72(172) is capable of articulation about latch pin71(171).

Right and left solenoids73and173are connected to latches70and170respectively, and disengage said latches when energized by the operator (not shown), who sends an electrical current to main power wire76(shown inFIG. 4) and thence to right and left power wires75(shown inFIG. 4) and 175, which in turn energize solenoids73and173respectively. It is desirable that the latches disengage simultaneously.

Right and left finger cables60and160serve as flexible tensile links connecting respective load arms34and134to respective finger assemblies40and140. Finger cable60(160) has an upper portion connected to finger cable arm mount56(156) on the outer portion of load arm34(134) and a lower portion connected to finger cable mount59(159) on finger frame43(143).

The grapple's operation is characterized by a cycle of (a) grabbing and lifting a load, (b) ferrying the load to a desired location, (c) dumping the load, and (d) resetting the mechanism in preparation for grabbing the next load. For greatest clarity this cycle will be described beginning and ending with the ferrying stage as seen inFIG. 1.

It will be assumed in this description that the grapple is suspended from a helicopter (not shown) and that “the operator” refers to said helicopter's pilot (not shown). However, this assumption is not intended to limit the scope of conditions in which the grapple may be operated. The operation as described can be easily extended to include other means by which the grapple may be supported (e.g. by a ground-based crane) and/or controlled (e.g. by wireless remote control).

It will also be assumed, for the illustrative purposes of this description, that the load being manipulated comprises loose material such as mulch; however, this single example of particularly advantageous material is not intended to provide or suggest any limitation as to other types of loads the invention, in various expressions, could effectively manipulate.

FIG. 1shows the grapple apparatus16in the condition of ferrying a load18.

When the grapple is supported by a helicopter or other load-carrying device, main cable54(shown inFIG. 4) supports load cables36and136, which in turn support the outer portions of load arms34and134hinged about main hinge20. Finger cable60(160) connects load arm34(134) to finger assembly40(140). The solenoid73(173) on latch70(170) is normally de-energized, so latch hook72(172) holds lever hinge67(167), maintaining the upward and inward pulling force of connecting arm64(164) acting on finger assembly140(40) on the opposite half of the grapple. Finger assemblies40and140enclose the load, which generally sits on top of fingers46and146.

Generally the grapple is prevented from closing further by one or more of the following conditions being met:(a) finger cable60(160) is taut;(b) finger assembly40(140) is in contact with finger closed limit stop48(148) on main frame22(122); and/or(c) main frame122is in contact with optional frame inward stop pin38(shown inFIG. 7), if pin38is present in frame inward stop hole39; and/or(d) the load18is such that forces on it are sufficient to keep finger assemblies40and140apart.

Condition (a) is particularly advantageous as tension in finger cables60and160will ensure minimal shock loading when the load is released.

The precise spatial relationships between parts of the grapple may vary from load to load. However, in all of the above ferrying conditions, the load is securely retained and all parts of the grapple maintain essentially constant positions relative to one another.

The dumping operation may be executed at any altitude suitable for the application, provided that t he loaded grapple is airborne, i.e. the preponderance of its weight is supported by main cable54.

The helicopter or other suspending device may be stationary or in motion at a speed suitable for the application. For example, when aerially spreading thin layers of mulch over large areas, it can be advantageous to release the load from a moving helicopter for broader dispersal and higher efficiency.

When the load is to be released, the operator activates an electrical control switch (not shown) which energizes solenoid73(173) which, in turn, causes latch70(170) to disengage. As lever hinge67(167) is released from latch hook72(172), connecting arm64(164) is able to straighten and extend, permitting frame assemblies21and121to move away from each other by rotating outward about main hinge20. Also, the disengagement of connecting arm64(164) from latch70(170) partially relieves load arm34(134) of the weight of the grapple and load, causing the outer portion of said load arm to move upward and inward relative to main hinge20due to tension on load cable36(136). This movement of load arm34(134) also pulls upward on finger cable60(160), tightening said cable and causing outward rotation of finger assembly40(140) about finger hinge26(126) and of frame assembly21(121) about main hinge20. If finger cable60(160) has already been under tension prior to dumping, minimal shock loading will be transferred to the helicopter or other suspending device.

The grapple will continue to open further until at least one of the following conditions is met:(a) Finger assembly40(140) contacts finger open limit stop47(147).(b) Main frame122contacts main stop pin29(shown inFIG. 7) in main stop hole33.

With the grapple thus opened, especially with the large distance between finger assemblies40and140and the generally vertical orientation of fingers46and146, the load (not shown) drops.

After dumping, the grapple may be safely ferried in the resulting empty open condition to the subsequent site where a load is to be grabbed.

FIG. 3shows one load arm34and related parts at an arbitrary point during the resetting operation; the other load arm134(not shown inFIG. 3) and its related parts act in essentially the same way.FIG. 4shows the entire grapple when the resetting operation is completed. Simultaneous reference to both drawings is recommended for this portion of the description.

The resetting operation is executed at the site where the next load is to be grabbed. The operator lowers the grapple to the ground. As main cable54(shown inFIG. 4) lowers and slackens, the weight of load arm34(134) causes said arm to rotate about main hinge20, in the direction of arrow90, toward a lowered position.

Pull arm upper lever66rotates about lever arm hinge65in the direction of arrow92until lever hinge67engages latch hook72on latch70. Likewise, pull arm upper lever166rotates about lever arm hinge165until lever hinge167engages latch hook172on latch170, the result of which operation is seen inFIG. 4. The mechanisms in each half of the grapple, though equivalent in function, act essentially independently of each other and may not occur exactly simultaneously, especially on uneven or steeply sloped ground.

Once latch hooks72and172are engaged with lever hinges67and167respectively, the grapple is considered to be “reset” and prepared to grab the next load, which it may do immediately and in the same location where it has just been reset.

The reset operation requires only the machine's own weight and, like all other steps of the grapple's cycle of operation, can be performed without direct manual intervention. The reset operation also, like all other steps in the grapple's cycle of operation other than dumping the load, can be performed without need for external power.

Operation—Grabbing and Lifting

Continuing withFIG. 4, the grapple16straddles the load18and is supported by its fingers46and146on the load or ground. When main cable54is lifted, load cables36and136lift the outer ends of load arms34and134respectively, which rotate about main hinge20. The top of connecting arm64(164) is lifted by load arm34(134), transmitting force to the opposite finger assembly140(40), which rotates inwardly about finger hinge126(26) and also causes inward rotation of frame assembly121(21) about main hinge20. As finger assemblies40and140rotate, fingers46and146penetrate load18. The added weight of the load on fingers46and146allows a greater upward force to be applied to main cable54, which results in a greater torque applied to rotate finger assemblies40and140and corresponding greater penetrating force on the load.

When the torque on finger assemblies40and140is less than that required for fingers46and146to penetrate the load, the grapple begins to lift. This normally results in a decrease of the force required to penetrate the load, so finger assemblies40and140will start to rotate again and fingers46and146will penetrate farther into the load. There is minimal disturbance in the load as fingers46(146) rotate about finger hinge26(126).

Finger assembly40(140) continues to rotate until at least one of the following conditions is met:(a) the force required to penetrate the load18is greater than that available on fingers46(146);(b) finger cable60(160) becomes taut;(c) finger assembly40(140) contacts finger closed limit stop48(148) on main frame22(122); and/or(d) main frame122contacts optional frame inward stop pin38(shown inFIG. 7), if pin38is present in frame inward stop hole39.

If condition (c) is the first to be met, frame assembly21(121), which comprises main frame22(122) and finger assembly40(140), may continue to rotate as a single unit about main hinge20until condition (a), (b), and/or (d) is met.

As the upward force on main cable54increases, the loaded grapple lifts off. The grapple, once airborne, exhibits the stable closed condition it will retain while being ferried to the dumping site. Thus it may be ferried as already described, and the cycle of grabbing, ferrying, dumping, and resetting can be repeated as many times as desired without interruption.

The grapple when operated as described offers increased safety and reduced cost, as all stages of its operating cycle can be controlled by the remote operator and therefore no ground crew is required. Further, no specialized skills are required of the operator as most load-handling is performed automatically by the grapple; for example, the operator need only lift the grapple in order to make it grab, and need only activate a switch in order to make the grapple dump.

Options and Alternatives

The description thus far has disclosed a main embodiment of the grapple apparatus and of the method used to operate it. What follows is a discussion of some optional components that may be added to the main embodiment, some particularly advantageous expressions of certain structures therein, and some alternatives to components of the main embodiment, including a second embodiment of the grapple featuring an alternative connecting arm.

Optional Damping Mechanisms

Shock absorption is most critical at the dumping stage of the grapple's operation. At this point, large forces are being transferred instantaneously, and helicopters are particularly sensitive to shock loading. While for most applications the tension in finger cables60and160(such as inFIGS. 1 and 2) prior to dumping minimizes shock loading, it is sometimes desirable to add additional damping capability at key places on the grapple. This is especially true when grasping unusually shaped loads that leave finger assemblies40and140further apart and finger cables60and160more slack than would otherwise be considered optimal behavior. In such a case, the rapid tightening of finger cables60and160would generate a larger-than-usual shock load.

This potential problem can be alleviated with one or more of the following modifications, all seen inFIG. 5.

A first possible modification involves attaching an optional frame damper41bridging main frame members22and122so that resistance in frame damper41will retard its extension and thus reduce the speed of frame opening.

A second possible modification involves replacing finger cable60(160) from the main embodiment (as seen inFIGS. 1 through 4) with alternative finger cable assembly260(360) as seen inFIG. 5. Finger cable assembly260(360) includes a finger cable damper52(152) having(a) a fixed upper cylinder53(153) attached to finger cable damper mount51(151), which is attached to finger cable arm mount56(156) on load arm34(134), and(b) a movable lower rod49(149) attached to the upper end of lower finger cable62(162), the lower end of which is attached to finger cable mount59(159).

Finger cable assembly260(360) further comprises upper finger cable63(163), the upper end of which is attached to finger cable damper mount51(151), and the lower end of which is clamped to lower finger cable62(162) at a point such that upper finger cable63(163) becomes taut just before finger cable damper52(152) is fully extended.

Thus, upper finger cable63(163) will be slack at first, allowing the pace at which finger cable assembly260(360) extends to be largely controlled and partially retarded by the extension of finger cable damper52(152). When finger cable damper rod49(149) has extended sufficiently for upper finger cable63(163) to become taut, finger cable assembly260(360) will behave similarly to finger cable60(160) in the main embodiment previously described.

A third possible modification involves replacing finger open limit stops47and147from the main embodiment (as seen inFIGS. 1 through 4) with alternative finger open limit stops247and347(seen inFIG. 5), comprising resilient material such as urethane placed where the stop would normally contact finger assemblies40and140respectively. The resilient material in stop247(347) will deform upon contact with finger assembly40(140) and absorb some of its kinetic energy.

A fourth possible modification involves introducing an optional resilient bushing32to travel over main frame limit rod28between main frame122and the main stop hole33in which main stop pin29is placed. Main stop resilient bushing32comprises resilient material in order to absorb shocks when rapid outward rotation of main frame members22and122is halted by main stop assembly25. (FIG. 5also depicts an optional frame inward stop bushing35which could serve a similar function by absorbing energy from inward rotation of main frame members22and122.)

The above modifications may be employed individually or in combination as the application requires. Whichever combination of modifications is implemented, the operating cycle of the grapple remains essentially the same as that described for the main embodiment.

Optional Springs

The resetting operation described as part of the main embodiment (and seen inFIGS. 3 and 4) is already simple and effective, relying as it does only on the weight of load arm34(134) to reset latch70(170). However, in some cases it may be desirable to have downwardly and inwardly directed force acting on load arm34(134) in addition to its weight. One example of such a case could involve attempting to reset the grapple while it is positioned on a steep hillside such that the right half of the grapple, including load arm34, stands much lower than the left half. Resetting latch70on load arm34in this case would require some inward force, which could be provided by the introduction of an extension spring. As seen inFIG. 5, spring74, mounted between spring frame mount177on main frame122and spring arm mount78on load arm34, is positioned advantageously to exert sufficient pulling force to supplement the weight of load arm34in order to complete the resetting operation.

Likewise, though not explicitly shown inFIG. 5, the equivalent spring174, mounted between spring frame mount77on main frame22and spring arm mount178on load arm134, would provide similar function.

Apart from a possible increase in the efficiency and effectiveness of the resetting operation provided by the springs, the operating cycle of the grapple remains essentially the same as that described for the main embodiment.

Optional Netting Enclosure

The ability of the grapple to retain certain types of loads can be improved if the preponderance of the grapple's frame21(and121, not shown inFIG. 6) is enclosed with netting material95as seen inFIG. 6. Further, the effectiveness of netting material95in enclosing the load being grabbed, lifted, or ferried can be improved by installing netting mounting springs96,97,98, and99on the edges of finger frames43and143not already joined by finger mounts44or144or finger hinges26or126to other components.

The operating cycle of the grapple with netting is the same as that described for the main embodiment.

Advantageous Arrangement of Fingers

In an advantageous arrangement, seen inFIG. 6, the shape of each finger46(146) is based on an arc with radius approximately equal to the perpendicular distance from its respective finger mount44(144) to finger hinge26(126) where main frame22(122) meets finger assembly40(140). Thus, the distance from finger mount44(144) to finger hinge26(126) is approximately equal to the distance from finger tip45(145) to finger hinge26(126).

The spacing and number of fingers46(146) on finger frame43(143) are variable. Fingers46(146) may be detached from finger frame43(143) at finger mounts44(144) in order to vary their spacing and/or number, and/or to interchangeably install fingers of various sizes and types (not shown) to accommodate particular characteristics of a load to be handled. It is not necessary that fingers are uniform.

Generally, changes to the spacing, number, size, and/or type of fingers will change the effectiveness of the grapple for certain types of loads, but will not change the operating cycle as described for the main embodiment, which remains essentially the same.

Advantageous Arrangement of Main Stop Assembly

In an advantageous arrangement of main stop assembly25, seen inFIG. 7as a simplified top sectional view (the sectioning plane being shown inFIG. 1), main frame limit rod28is hinged at its proximal end to main frame22by main stop hinge27. The intermediate portion of main frame limit rod28is encircled by main stop slider31, which includes a bolt that attaches to main frame122in such a way that main stop slider31is free to partially rotate about the axis of the bolt. As the frame opens, main stop slider31travels toward the distal end of main frame limit rod28until stopped by contact with main stop pin29placed in a main stop hole33located on main frame limit rod28.

Likewise, if frame inward stop pin38(not shown) is present in frame inward stop hole39, main stop slider31will travel toward the proximal end of main frame limit rod28, as the frame closes, until stopped by contact with frame inward stop pin38.

This arrangement of main stop assembly25accommodates a wide range of realistic conditions for controlling the opening and closing of the grapple, as main frame limit rod28can rotate freely with respect to main frame22about main stop hinge27, and can also move freely back and forth within slider31, which itself can rotate freely with respect to main frame122.

In the operation of the grapple using this arrangement, unlike the operating cycle described for the main embodiment, it is main stop slider31(rather than main frame122directly) that contacts main stop pin29at the dumping stage, and frame inward stop pin38(if present) at the grabbing stage. All other elements of the operating cycle remain essentially the same.

Alternative Arrangement of Load Cables

As seen inFIG. 8, load cables36and136can be replaced by an alternative load cable236which is a single piece of cable joined at each end to a load arm34or134(seeFIG. 4) and passing over a cable pulley253attached to alternative load cable mount250, which in turn is attached to main cable54(seeFIG. 4). The rolling action of load cable236over cable pulley253allows the forces on the two ends of load cable236to equalize and thereby essentially equalize the forces on the two load arms34and134.

Apart from possibly improved performance with certain types of loads, the operating cycle with this arrangement of load cables remains essentially the same as that described for the main embodiment.

Additional Embodiment Featuring Alternative Connecting Arm

Many systems in this additional embodiment are unchanged from the main embodiment as seen inFIGS. 1 through 4:(a) right and left frame assemblies21and121are still hinged together at main hinge20, and frame assembly21(121) still comprises main frame22(122) and finger assembly40(140) hinged together at finger hinge26(126);(b) main frame stop assembly25still bridges main frame members22and122and still comprises main frame limit rod28, main stop pin29, and main stop hole33, as well as frame inward stop hole39and frame inward stop pin38(if present);(c) finger assembly40(140) still comprises finger frame43(143) and fingers46(146), the fingers still being mounted to finger frame43(143) at finger mounts44(144) and having finger tips45(145);(d) finger open limit stop47(147) on main frame22(122) still limits inward rotational movement of finger assembly40(140);(e) the grapple is still connected to a helicopter or other supporting apparatus by load cables36and136, which are connected to main cable54at load cable mount50;(f) latch70(170) still comprises latch pin71(171) and latch hook72(172), and is still released by momentary power to solenoid73(173), which is still connected to a power source and control switch (not shown) by power wires75and175and main power wire76.

The additional embodiment further comprises several components that are substantially altered with respect to the main embodiment, which are described as follows with reference toFIG. 9. Where only one half of a pair of components is shown, it is to be understood that the other half generally acts as a mirror image of the same.

Right and left alternative load arms434(not shown) and534are hinged together at main hinge20. Load arm534(434) is arranged so that it has a longer portion on one side of main hinge20that cooperates with load cable136(36) and a shorter portion on the opposite side of main hinge20that cooperates with alternative connecting arm464(and564, not shown).

Alternative connecting arm464(564) comprises push arm rod455(and555, partially shown), the lower portion of which is connected to push arm lower hinge457(557) on alternative lower arm mount458(558), and the upper portion of which, terminating with push arm pin467(and567, not shown), is angled to engage with latch hook72(172) on latch70(170).

The movement of connecting arm464(564) is guided by alternative guide lever469(and569, not shown), which is mounted at one end to load arm534(434) at alternative lever arm hinge465(and565, not shown) and at the other end to push arm rod455(555) at alternative guide hinge461(and561, not shown).

The embodiment further comprises finger cables similar to those in the main embodiment. Alternative finger cable560(and460, partially shown) is connected between alternative finger cable arm mount556(and456, not shown) on load arm534(434) and alternative finger cable mount559(459) on lower arm mount558(458).

The embodiment further comprises right and left alternative finger closed limit stops448and548attached to main frame members22and122respectively. Finger closed limit stop448(548) has an elongated shape relative to corresponding finger closed limit stop48(148) in the main embodiment (seeFIGS. 1 through 4) to accommodate the altered shape of lower arm mounts458and558(seeFIG. 9) relative to corresponding lower arm mounts58and158in the main embodiment (seeFIGS. 1 through 4).

Operation of Additional Embodiment

The operation of this additional embodiment follows the same cycle as the main embodiment. As with the main embodiment, the operating cycle will be described beginning and ending with the ferrying stage. Where deviations from the operation of the main embodiment are not explicitly mentioned, it is to be understood that the operation of the additional embodiment is essentially the same with respect to the point not mentioned.

Similarly, all components common to the two embodiments function identically in each embodiment, except where specifically noted in the operational description below. It is further noted that, with respect to function, the following components may be treated as identical between embodiments:(a) finger cable460(560) in the additional embodiment is functionally identical to finger cable60(160) in the main embodiment;(b) finger closed limit stop448(548) in the additional embodiment is functionally identical to finger closed limit stop48(148) in the main embodiment; and(c) the outer portion of load arm534(434), that is, the portion between main hinge20and finger cable arm mount556(456) inclusively, in the additional embodiment is functionally identical to the outer portion of load arm134(34), that is, the portion between main hinge20and finger cable arm mount156(56) inclusively, in the main embodiment.

Simultaneous reference toFIGS. 1 through 4(for the appropriate stages of operation of the main embodiment) and toFIG. 9(for the additional embodiment) is recommended, especially as the latter is primarily understood in direct comparison to the former.

The ferrying operation of the additional embodiment is identical to that of the main embodiment, except that(a) it is push arm pin467(567), rather than lever hinge67(167), that remains engaged with latch hook72(172) as long as solenoid73(173) remains de-energized, and(b) the force from connecting arm464(564) acting on finger assembly140(40) is a downward and inward pushing force in the additional embodiment, in contrast to the upward and inward pulling force from connecting arm64(164) in the main embodiment.

The dumping and resetting operations show more variation between embodiments.

In the additional embodiment, when momentary power from the operator's electrical control switch (not shown) energizes solenoid73(173) causing latch70(170) to disengage, push arm pin467(567) is released from latch hook72(172). Connecting arm464(564) is able to move away from latch70(170), being limited by movement of arm469(569) about lever arm hinge465(565) and guide hinge461(561), and being further limited by movement about push arm lower hinge457(557). Frame assemblies21and121are permitted to move away from each other by rotating about main hinge20. Also, the disengagement of connecting arm464(564) from latch70(170) partially relieves load arm534(434) of the weight of the grapple and load, causing the outer portion of said load arm to move upward and inward relative to main hinge20due to tension on load cable136(36). This movement of load arm534(434) also pulls upward on finger cable560(460), tightening said cable and causing outward rotation of finger assembly140(40) about finger hinge126(26) and of frame assembly121(21) about main hinge20.

Also, though the two embodiments share a common latch70(170), the additional embodiment is reset when push arm rod455(555) rotates about push arm lower hinge457(557) and guide lever469(569) rotates about lever arm hinge465(565) and guide hinge461(561) until push arm pin467(567) engages latch hook72(172) on latch70(170). As in the main embodiment, the resetting operations for the two halves of the grapple, though related to each other, are not necessarily exactly simultaneous.

Finally, the grabbing operation of the additional embodiment is identical to that of the main embodiment, except that the force from connecting arm464(564) acting on finger assembly140(40) is a downward and inward pushing force in the additional embodiment, in contrast to the upward and inward pulling force from connecting arm64(164) in the main embodiment.

Generally, this additional embodiment offers an operational advantage over the main embodiment in cases where it is important to reduce potential interference between the load18and the internal components of the grapple that could contact it, specifically lower arm mounts58(158) and connecting arms64(164) in the main embodiment. The additional embodiment has an uncluttered interior cavity and therefore reduces the possibility of interference by or with the load.

However, the main embodiment has the contrasting advantage of more significantly reducing stresses on components and shock loading on the helicopter or other supporting apparatus when the grapple is opened. For example, the force transferred in load arm34(134) from a pull on lever arm hinge65(165) to a pull on finger cable arm mount56(156) is less severe than the force transferred in load arm534(434) from a push on lever arm hinge465(565) to a pull on finger cable arm mount556(456).

All embodiments described in this disclosure, while illustrative of the essential features of the grapple apparatus and of the method described for its use, shall not be interpreted as limitations on the scope of the invention, which is capable of other expressions than those explicitly described.