BACKGROUND OF THE INVENTION
This invention relates to dollies for transporting large flat objects, such as doors or large panels of the type used in the building and construction trades. It is often necessary to move such hard to handle objects as wall panels, doors, sheets of plaster board, and the like from one location to another at a construction site. Generally, two workmen are required for this job since the size of the objects make them cumbersome, if not impossible, for one person to handle. Use of a dolly would permit one workman to perform the task alone.
Other dollies which have been used for similar purposes have had various drawbacks. One type has no means for clamping the dolly to the object to be transported. This makes it inconvenient for lifting the dolly over small obstructions. The second type requires shims to be used for the dolly to accommodate objects of various widths. Another type has clamping means which tend to damage a relatively soft surface such as wood or plaster board. Yet another prior art type of dolly has its wheels arranged longitudinally, making the dolly unstable in the lateral direction. The dolly of this invention avoids all of these shortcomings.
BRIEF SUMMARY OF THE INVENTION
The invention resides in a dolly which rolls on two wheels laterally disposed to the direction of motion and having two clamping members for gripping a flat object to be transported thereon. The dolly comprises two clamping members on a longitudinal center line, and wheels are so positioned that the weight of the load causes the clamping members to pivot toward one another. These members can be clamped to resist outward movement, thereby gripping the lead to prevent it from sliding. Mechanical means for so clamping these members permits the load to be firmly held irrespective of its weight and allows the dolly to be lifted by the object being transported thereon to clear small obstructions or the like. The clamping members have flat object gripping surfaces which may be covered with a soft cushioning material, as may be the floor of the dolly, so that easily marred surfaces will not be damaged. Also, the distance between the clamping members is adjustable to accommodate objects of various widths without the need for shims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the dolly with an exploded view of one of the wheel mountings and with one of the clamping members in an alternate position, as indicated by the phanthom lines.
FIG. 2 is a perspective view of the dolly being used to transport an object.
FIG. 3 is a vertical sectional view taken on the line 3-3 of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to the drawings in greater detail, FIG. 1 shows a dolly of this invention as generally indicated at 5. The floor of the dolly is a butt hinge 10 comprising two leaves 11, 12 the adjacent edges of which define as opening for receiving a pintle 14. Two generally L-shaped angle brackets 20, 20 are secured to the hinge leaves, 11 and 12 respectively, by means of nuts 22, 22 and bolts 24, 24. Support struts 28, 28 are preferably welded, or otherwise suitably secured diagonally across the legs or flanges of said brackets 20, 20 for extra strength and to define a boss for the stub shaft 32. Elongated mounting holes 26, 26 in the base leg of at least one of the brackets allow the lateral space between the two brackets to be adjusted for accommodating objects of various widths.
Two wheels 30, 30 are provided, each of which is mounted on a stub shaft 32 carried by the base leg of each of said brackets 20, 20. These shafts are suitably secured to said bracket legs or flanges and protrude laterally therefrom. The wheels may be held on said shafts by means of cotter pins 34, 34 or other suitable means.
It is evident that the weight of an object on the floor of the dolly will cause the two upstanding flanges to pivot toward each other along the hinge line toward the position indicated by the phanthom lines of FIG. 2, thereby clamping the supported object therebetween. This clamping force will generally be sufficient to prevent the supported object from sliding on the dolly. To more securely clamp the dolly to the object to be transported, and to provide a clamping force irrespective of object weight, clamping means 40 is provided.
More particularly, said clamping means comprises a cross arm 42 secured to leaf 11 of hinge 10 by means of a bolt 44 and a nut 46. It will be apparent that other suitable means might also be used, as for example, a welded joint. The cross arm 42 extends laterally below the hinge across the hinge pintle 14. A thumb screw 48 is threaded through the cross arm, or through a nut 15 welded to the cross arm, and pushes against the bottom of leaf 12. When the thumb screw 48 is tightened, the clamping brackets 20, 20 are forced to pivot toward one another on the hinge line defined by pintle 14, thereby exerting the required clamping force.
The inside walls of the clamping brackets 20, 20, as well as the top portion of hinge 10 which forms the floor of the dolly, may be lined with a soft material such as rubber or cork to prevent damage to the surface of the object being transported.