A lift mechanism includes a balance structure configured to hold an object, wherein the balance structure is rotateably connected to an arm structure at a pivot point. The pivot point is configured, and the object is positioned, such that the pivot point is substantially coincident with the center-of-mass of the object being moved. Weights may be selectively attached to the balance structure to adjust the center-of-mass. In one embodiment, the lift mechanism includes a base and an arm configured to rotate with respect to the base, wherein the arm is attached to the balance structure at the pivot point. In this way, heavy objects may be lifted, translated, and rotated into place safely in an efficient manner.

TECHNICAL FIELD

The present invention generally relates to lift mechanisms, and more particularly relates to a lift mechanism incorporating a center-of-mass balance.

BACKGROUND

During the maintenance and assembly of large machinery (e.g., aircraft and the like), it is often necessary to move, lift, and rotate relatively heavy objects in order to place them in the correct position and orientation with respect to other components. In general, with reference toFIG. 1, an object102having a center-of-mass106must be moved from a position110(a) to a position110(b) such that it can be attached to a mating component104. This repositioning generally requires a combination of lifting, translating, and rotating the object, which may be accomplished in any number of steps and in any number of ways. Various types of lift mechanisms are traditionally used for this purpose, including, for example, transmission jacks, trunnions, and other such devices.

Prior art lift mechanisms are unsatisfactory in a number of respects. For example, as it is often necessary to rotate the object into place, there is a risk that the object will pivot into an undesirable position, causing danger to the object as well as the individuals operating the mechanism. The object's center-of-mass may fall outside the base of the lift mechanism, for example, leading to tipping of the entire assembly.

Furthermore, prior art devices generally require three or four operators to move and hold the object in place, leading to inefficiencies during operation. Likewise, such devices are typically very large, and thus cannot be effectively used in tight spaces.

Accordingly, there is a need for a lift mechanism that is both safe and efficient, requiring a minimum number of individuals to operate, and allowing for a wide range of motion in a confined space.

BRIEF SUMMARY

A lift mechanism in accordance with the present invention includes a balance structure configured to hold an object, wherein the balance structure is rotateably connected to an arm structure at a pivot point. The pivot point is configured, and the object is positioned, such that the pivot point is substantially coincident with the center-of-mass of the object being moved. In one embodiment, the lift mechanism includes a base and an arm configured to rotate with respect to the base, wherein the arm is attached to the balance structure at the pivot point. In this way, heavy objects may be lifted, translated, and rotated into place safely in an efficient manner.

DETAILED DESCRIPTION

In general, a lift mechanism in accordance with the present invention allows for positioning of an object such that the object pivots around an axis extending through its center-of-mass (or center-of-gravity), and at the same time may be tilted upward and translated sideways to achieve the correct position and orientation.

Referring toFIG. 2, a lift mechanism in accordance with one embodiment of the present invention comprises a base202, one or more rolling components212, an arm204rotateably connected to base202via a pivot206, and a center-of-mass balancer (or simply “balancer”)208rotateably coupled to arm204via a pivot210. As shown, an object102seats within, is affixed to, or is otherwise connected to balance208such that its center-of-mass210A (as projected on the x-y plane shown in the side view) substantially coincides with pivot210. Stated another way, rotation of balancer208occurs around an axis passing through pivot210, and the center-of-mass of the object210A lies substantially along this axis. In this way, when balance208is rotated, the center-of-mass of object102remains in a known location with respect to the structure.

As shown inFIG. 3, the components of lift mechanism200may be articulated to move object102from a first position and orientation110(a) to a second position and orientation110(b). Generally, base202, arm204, and balance208are suitably moved to accomplish this task.

Rolling components212allow base202to be translated laterally with respect to the ground (or “reference surface”)250, and may comprise any rolling device now known or later developed, including various wheels, castors, and the like. More broadly, rolling components212may include any device allowing lateral movement of base202with respect to ground250.

Arm204is rotated with respect to base202through an angle θ such that pivot210is raised from a height h1(inFIG. 2) to a height h2(inFIG. 3). Movement of arm204may be effectuated through any convenient method, including pneumatics, gears, pulleys, or any other such mechanical actuation. Similarly, arm204may be held in place using a variety of mechanical techniques known in the art.

Balance208is rotated an angle α with respect to arm204around pivot210in order to orient object102for interfacing with the mating component. As mentioned above, it is desirable to position object102such that its center-of-mass coincides with pivot210. This may be accomplished a variety of convenient fixturing techniques. As with arm204, movement of balance208may be effectuated through any convenient method of mechanical actuation. Balance208may likewise be held in place with respect to arm204using a variety of mechanical techniques known in the art. In one embodiment, a clamping arrangement is used in connection with an axle extending outward from the pivot point, wherein the clamp contacts the outer diameter of the axel and is thereby held in place.

FIG. 4shows a particular embodiment of the present invention. Lift mechanism200includes three casters212situated in a triangular pattern and attached to base202, which generally has a “U”-shape. In one embodiment, base202comprises 6.0×4.0×⅜ steel angle structures, although any other suitable material, shape, or dimensions may be used.

Casters212(a),212(b), and212(c) (not shown) are fixed with respect to base202. Thus, lateral movement of the device is accomplished by applying force to base202and/or a steering device402. Steering device402may be fixed with respect to base202or coupled to one or more of casters212to effectuate rotation/translation of the entire unit.

An arm actuator408is used to rotate arm204about a pivot206. In the illustrated embodiment, arm actuator comprises a pneumatic jack device, although any other suitable mechanism might be used. Arms408may comprise any convenient material, for example, steel or other sufficiently strong material, depending upon the particular application and desired load. Pivot206may comprise, for example, two needle bearings with mating shafts, or any other sufficiently strong pivoting structure.

Balance208comprises two generally triangular side arms412rigidly coupled to a balance base410. Balance base410, in this embodiment, includes one or more openings406that allow subcomponents to be cleared, inserted or removed from the object during assembly. A securing mechanism404(e.g., a bolt, clamp, or the like) is used to rigidly connect the object to balance base410during operation. In the illustrated embodiment, the object may be rotated 360° with respect to base202without the center-of-mass of the object extending outside base202. In one embodiment, balance base410may be rotated plus or minus 360° without the center-of-mass of the object extending outside the balance base itself (i.e., as viewed from above mechanism200).

In accordance with another aspect of the invention, weights may be selectively added to the balance structure to adjust the center-of-mass of the balance structure/object system. More particularly, referring toFIG. 5, the underside of balance base410may include any number of indentations configured to receive weight inserts504. By placing a series of weights within balance base410, the effective center-of-mass of the system may be lowered—e.g., lowered such that the weight-distribution of top-heavy objects can be counteracted to align the effective center-of-gravity with the pivot point of the balance structure. Selecting the position and magnitude of any such weights may be accomplished in any number of ways. For example, the weights may be selected manually using trial and error to determine whether the object is properly balanced. Alternatively, the object may be modeled using any suitable modeling software, allowing the center-of-mass to be determined computationally.

As shown, balance208, arm204, and base202are moved individually or in concert in a way that is safe and efficient, requiring only one individual for operation. By configuring object110so that it rotates substantially around its center of mass, the lift operates safely and is not likely to tip or cause other dangerous situations.

While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. For example, movement of the various components in the illustrated embodiment is performed manually; however, computer control and/or automatic control systems may be incorporated. Furthermore, the dimensions and scale of the illustrated embodiment are not intended to be limiting. In addition, while the present invention is illustrated as rotating within a plane, the invention may be implemented to articulate and rotate along a third axis.

It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.