Mobile load support

A mobile load support for cradling and moving heavy loads comprises a pair of axles in spaced apart parallel relationship to each other, having corner units pivotally mounted on respective ends of the axles. Each of the corner units comprises a truck body having swivelable castor wheels disposed at each end thereof, and a platform projecting therefrom at a level below the longitudinal axis of the truck body for cradling a corner of the load. A pair of ratchet straps engages the ends of the axles, and can be tightened to secure the mobile load support around the load. The mobile load support is capable of manoeuvring over uneven surfaces due to the pivoting action of the corner units, which reduces the tendency of the load becoming dislodged from the support, and is flexible in that it can be easily adapted to loads of different sizes.

FIELD OF THE INVENTION

The present invention relates in general to movable supports, and more specifically to a mobile support structure for moving heavy loads such as machines.

BACKGROUND OF THE INVENTION

Traditionally, individual skates, dollies, castors or rollers have been used to support heavy equipment or machinery for movement thereof from one area to another. A roller is inserted under each corner of a machine, for example, in order to provide rolling support to facilitate the moving of the machine. Typically, the rollers raise the machine 4–6″ off the ground, and the only connection provided between the machine and the rollers is the weight of the machine bearing down on the rollers. However, if the floor over which the machine is being moved is uneven, and should one of the rollers encounter a rut or protrusion in or on the surface, it is quite easy for one of the rollers to become dislodged from the load and for that corner of the machine to fall to the ground. When considering top-heavy machines, such a drop could result in the entire machine tipping over with disastrous results.

Various other mobile supports have been developed that include some type of frame that connects four corner rollers together in order to avoid the situation of having one of the corner rollers becoming dislodged from beneath the load. However, the structures are not easily adaptable to different sized loads since the frames consist of rigid members that are specifically fabricated to provide a certain low degree of adjustability, and they are usually cumbersome to adjust. Furthermore, the load is often raised a number of inches off the ground which still presents a hazard if the load were to become dislodged from one corner of the support.

Canadian Patent No. 2,323,848 to Hewitt discloses a mobile base assembly for supporting and moving machinery. The base assembly comprises corner members having platforms that support the load, extension members connecting the corner members together, support wheels and castor wheels, and at least two stops for supporting the base in a stationary position. The corner and extension members utilize a series of holes that are aligned with respect to each other, and then secured together using nuts and bolts. This allows the size of the base to be adjusted to accommodate a variety of load sizes. Although the base is adjustable, the use of nuts and bolts to join the corner and extension members together is cumbersome. Furthermore, the base is not easily adapted to accommodate extra support wheels or castors, which limits the load carrying capacity of the mobile base.

U.S. Pat. No. 5,044,645 to Eltvik teaches a U-shaped dolly apparatus for supporting and moving heavy objects. The device surrounds the intended load on three sides, with the weight of the load being supported by the two end members while the side member telescopes to adjust to the length of the load. The end members include large wheels, however the wheels do not pivot or swivel to allow for easy steering of the apparatus. Once again, adjustability is provided by means of specifically fabricated pieces that are aligned and locked together.

U.S. Pat. No. 5,358,264 to Hewitt reveals an I-shaped apparatus for supporting and moving heavy objects, typically machinery. The device essentially comprises two parallel end members connected by a centrally located longitudinal member creating the I-shape. One of the end members mounts a pair of pivoting castors, arranged at opposite ends thereof, while the other end member has a single centrally positioned swivelable wheel. The apparatus is of a fixed size and accordingly cannot be adjusted to fit different-sized loads.

U.S. Pat. No. 4,066,272 to Cobb discloses dolly means comprising individual units that have a frame with a supporting surface for engaging the heavy load, and four independent axles mounted beneath the surface with wheels rotatably mounted thereon. Each axle is capable of vertical movement, which allows one or both of its wheels to move up or down to respond to an uneven surface. The use of the dolly means, however, will often require more than one of the individual units with, for example, one of the units being placed under each corner of the load. Cobb's device improves upon the conventional use of skates or rollers by introducing independent axles beneath a single platform, which helps to reduce the likelihood of the device slipping out from beneath the load since the units can adjust to uneven surfaces. However, the possibility of one of the units becoming dislodged still exists as there is nothing holding each unit together in an overall assembly.

SUMMARY OF THE INVENTION

It has been found that incorporating pivoting movement to the wheel supports of a mobile load support or dolly, and that using flexible members to connect elements of the mobile load support or dolly together helps to alleviate some of the disadvantages and inconveniences previously encountered with prior art dollies.

Accordingly, the present invention seeks to provide a mobile load support apparatus comprising a pair of axles in spaced apart parallel relationship to each other and having corner units pivotally mounted on respective ends of the axles. Each of the corner units comprises an elongated body having wheels disposed at each end thereof, and a platform projecting therefrom at a level below the centre of the elongated body for cradling a corner of the load. Flexible linking means capable of engaging the ends of the axles, and including tensioning or tightening means, are provided to connect the axles together and secure the dolly apparatus around the load.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, there is shown inFIG. 1the mobile load support or dolly apparatus10according to the present invention. According to the preferred embodiment, the mobile load support apparatus10utilizes a pair of axles12a,12bin spaced apart parallel relationship to each other, for positioning at respective forward and rearward ends of a load11. Individual corner units14a–dare provided for mounting to each of said axles adjacent each end thereof for supporting the load. Each of the load supporting corner units14a–dis equipped with a pair of castor wheels16a,16bwhich provide for easy movement of the mobile load support apparatus10in any direction along the ground as they are rotatably connected to the corner units14a–dfor swivelable movement with respect thereto. Ratchet straps18a,18bserve as flexible linking means to connect the axles together in their spaced apart relationship about the load11and impose a tension load thereon to draw the forward and rearward axles together. Each of the ratchet straps18a,18bhas a loop20at each end thereof for receiving a respective end of the axles12a,12b,and can be adjusted in length to suit the size of the load11. When the straps18a,18bhave engaged the ends of the axles, the straps18a,18bare tensioned or tightened using a ratchet mechanism21to ensure that the mobile load support apparatus10is secured around the load11. The straps18a,18bmay be made of any suitable material that provides the required strength such as polypropylene or high quality polyester. This material not only provides adequate strength for the webbing of the straps, but it also helps to eliminate stretching of the webbing while the straps18a,18bare being tightened.

Any conventional ratchet mechanism21may be used to tighten the straps18a,18b.Typically, ratchet mechanisms comprise a toothed wheel on which a pawl rests, and an actuating lever for operating the ratchet. The lever operates between a locked closed position wherein the strap tension is maintained and a locked open position which releases the tension load on the strap and allows the strap to be freely pulled in the non-tensioning direction. The operation of the lever between these two positions results in tightening of the strap. The pawl is positioned so that it can move over the teeth of the ratchet; however, once the actuating lever is in the locked closed position, the pawl engages the teeth of the ratchet thereby preventing movement of the strap in the non-tensioning direction.

As shown inFIGS. 2a,2band3, each corner unit is comprised of an elongated body or truck body22having an outer face24facing away from the load11and an inner face26adjacent the load11. The castor wheels16a,16bare disposed at each end of the elongated body22. Castor wheels16a,16bare mounted to the body22in a conventional manner so that they can swivel about a vertical axis. A mounting tube28extends from the outer face24of the truck body22through the thickness thereof, and projects transversely beyond the inner face26of the truck body22, creating a projecting portion29. A load supporting platform30for cradling a corner of the load11is connected at one edge32thereof, as by welding, along the length of the projecting portion29of the mounting tube28, and along an adjacent edge34to the inner face26of the truck body22. The platform30is connected to the projecting portion29of the mounting tube28near the lowermost part of the-mounting tube28. Therefore, the platform30is positioned below the longitudinal axis of the mounting tube28. When the load11is placed on the mobile load support apparatus10, the positioning of the platform30on each of the corner units14a–dallows the load11to be cradled at a level lower than the longitudinal axis of the mounting tube28and the longitudinal axis of the truck body22. As a result, the load11is raised no more than about an inch off the ground; therefore the load11and the mobile load support apparatus10together, will have a relatively low centre of gravity. This contributes to the stability of the load11on the mobile load support apparatus10since the tendency of the load11to tip is reduced. Furthermore, even if the load becomes dislodged from the mobile load support apparatus10or if the mobile load support apparatus10fails, the amount of damage would be minimal since the drop would only be about an inch.

Once the load11is placed on the mobile load support apparatus10and the ratchet straps18a,18bhave been tightened, the load11can easily be transported in any direction due to the swivelling ability of the castor wheels16a,16b.The structure and mounting of the corner units14a–dalso contribute to the ease with which the load11can be transported since the corner units14a–dcan pivot about their respective axles12a,12b.As a result of the pivoting movement of the corner units14a–d,when the mobile load support apparatus10encounters slight discrepancies in the level of the ground or floor such as small objects, a change in floor surface or just the general unevenness that is common of workshop or warehouse floors, the corner units14a–dare able to accommodate the changes in the surface. This further reduces the tendency of the load11to become dislodged from the mobile load support apparatus10since the likelihood of one or more of the corner units14a–dstopping abruptly as they encounter small obstacles on the floor is reduced.

As shown inFIG. 3, when the mobile load support apparatus10encounters a slight incline on the floor surface for example, the corner unit14awill pivot and adjust to the incline. The front castor wheel16awill maintain contact with the ground and will be followed by the rear castor wheel16b.The pivoting movement of the corner unit14awill result in movement of the platform30with respect to the load11, indicated by X inFIG. 3. However, the distance created between the load11and the platform30is very small so as not to de-stabilize the load11on the mobile load support apparatus10.

The mobile load support apparatus10is mainly adapted for use with square or rectangular shaped objects. It is especially suitable for moving production machinery in a shop or for moving pallets in a warehouse, and may even be used for mounting and moving wheeled vehicles such as cars or trucks. However, other differently shaped objects may also be transported using the dolly apparatus10by first placing the load11on a square or rectangular pallet36, which can then be used with the mobile load support apparatus10, as shown inFIG. 4. The mobile load support apparatus10of the present invention is also versatile since, because the corner units14a–dof the dolly10are free sliding along the length of the axles12a,12b,they can be easily adjusted to suit the width of the specific load11being transported. The mobile load support apparatus10is further adaptable since axles12a,12bof various lengths may be used, provided they are appropriately sized to receive the corner units14a–d,which also helps to accommodate different sized loads11. Therefore, the free-sliding of the corner units14a–d,the ability to use axles12a,12bof different lengths, and the use of adjustable straps all contribute to the flexibility of the mobile load support apparatus10and the ease with which it can be adapted to accommodate loads of different sizes.

The mobile load support apparatus10may also be equipped with additional corner units that act as support units38which can increase the load-carrying capacity of the device. The support units38may be the same as the primary corner units14a–dor they may have a slightly different structure that does not include a platform30. The mobile load support apparatus10utilizing additional support units38(without platforms30) is shown inFIG. 5.

In another embodiment of the invention, the corner units14a–dmay be adapted to be more suited for carrying wheeled vehicles, as shown inFIG. 6. In such an embodiment the mounting tube28on each of the corner units14a–dhas a projecting portion29of a length that is greater than the width of the tire of a vehicle, and the truck body22and platform30are sized appropriately as well. As shown in more detail inFIG. 7, the platform30is adapted to have a slightly bevelled or bent leading edge40. The bevelled leading edge40facilitates loading the wheeled vehicle on to the mobile load support10since the slight incline created by the bevel tends to urge the wheels of the vehicle on to the platform30.

When loading a wheeled vehicle on to the mobile load support10, axles12a,12bwith the corner units14a–dmounted thereon are placed at the front and rear of the vehicle with the bevelled leading edge40of the platform30of each of the corner units14a–dadjacent the tires of the vehicle, which has been placed in neutral. The straps18a,18bare then connected to each of the axles12a,12b,and are then tightened, causing the platform30of each of the corner units14a–dto be wedged further under the tires of the vehicle until the vehicle is properly supported on the mobile load support10and ready for transport.

According to another embodiment of the invention (seeFIGS. 8 and 9), the mobile load support apparatus10may include forward and rearward sets of corner units14a–d′ that are structured so that the ends23a′,23b′ of the elongated body22′ of the corner units are offset with respect to the longitudinal axis A thereof by an angle α. The end23a′ of the forward set of corner units14a′,14b′ that is most distal to the load11is angled in a direction toward the load, while the end23b′ of the corner units14a′,14b′ that is most proximal to the load11is angled in a direction away from the load. The rearward set of corner units14c′,14d′ are structured so that they are the mirror image of the forward set or reversed relative thereto. Therefore, the end23a′ of the corner units14c′,14d′ that is most distal to the load11is angled in a direction toward the load11, while the end23b′ that is most proximal to the load11is angled in a direction away from the load11. The offset creates additional clearance C to accommodate the 360° swivelling movement of the castor wheels16a,16band helps to avoid unwanted interference between the castor wheels16a,16band the load11. The offset that is created is typically in the range of 15° to 20° with respect to the longitudinal axis of the elongated body22′.

As can be seen inFIG. 9, additional support units38′ may also be used when the mobile load support apparatus10is equipped with the offset corner units14a–d′. Once again, the additional support units38′ do not need to include a platform30and they may be used in conjunction with only one set of corner units, as shown inFIG. 9wherein they are used with the rearward set of corner units14a′,14b′.

While the mobile load support or dolly apparatus of the present invention has been described in reference to the preferred embodiments, it will be understood by those skilled in the art that variations may be incorporated into the mobile load support apparatus10without departing from the scope of the invention. For instance, the axles12a,12bmay be made of metal tubes or solid rods of any suitable material, and may have grooves42formed around their outer circumference adjacent the ends thereof for receiving the flexible linking means. The grooves42help to ensure that the straps18a,18bremain in position around the ends of the axles12a,12bas shown inFIG. 10. As well, the axles12a,12bmay be made of telescoping tubes to provide additional adjustability rather than using tubes or rods of different lengths (seeFIG. 11).

The preferred embodiment has also been described as using ratchet straps18a,18bto hold the axles12a,12bin spaced apart parallel relationship with respect to the load11. However, the axles12a,12bmay be connected using any suitable flexible linking means capable of securing the dolly apparatus10with respect to the load11. The straps18a,18bdo not necessarily need to be of the ratcheting type provided they are equipped with any other suitable means for tightening the straps, for example a buckle or any equivalent that allows the length of the strap to be adjusted. Furthermore, the straps do not need to be connected to the axles12a,12bby loops20on their respective ends. Any other suitable means for attaching the straps18a,18bto the axles may be used, such as hooks that are capable of grasping the ends of the axles. As well, the straps18a,18bdo not need to engage the ends of the axles12a,12bprovided suitable means for receiving the engaging ends of the straps18a,18bare provided on the load supporting corner units14a–d. For instance, the outer face24of the corner units14a–dmay be provided with a projection44for receiving the loops or hooks of the engaging ends of the straps18a,18b,as shown inFIG. 12a.Alternatively, when the engaging means at the ends of the straps18a,18bare hooks, the corner units14a–dmay be provided with an engaging hole46in either the outer face24or top of the elongated body22for receiving the hooks and thereby securing the mobile load support apparatus around the load11, as shown inFIG. 12b.When the corner units14a–d′ with the offset ends are used, the engaging hole46is positioned on the top surface of the elongated body22to facilitate engagement with the straps18a,18b.

Therefore, it will be well understood by those skilled in the art that the mobile load support10of the present application has numerous applications and should not be limited to those described herein.