Dolly Frame

This invention relates to dollies in general, and more particularly relates to the frame of a dolly that is secured to the bottom of a barrel or tank which is standing on end.

There are many mobile devices that include barrels or tanks positioned standing on end. Typical of such devices are so-called bypass type vacuum cleaners where a suction-producing fan means is removably mounted to the top of a tank wherein dirt, including liquid, is collected. These tanks are mounted on dollies that are usually provided with means for securing the tanks to the dollies.

Many prior art dollies of this type include a base that is constructed of relatively expensive elements or there are many elements that are costly to assemble, and there is very little flexibility insofar as being able to use a particular dolly for many tanks that fall within a reasonably large acceptable range of dimensional variation. An example of a prior art dolly of this type is found in copending U.S. patent application Ser. No. 803,254, filed Dec. 2, 1985 in the name of R. C. Berfield, R. L. Crevling, Jr. and D. G. Rightnour, and titled DOLLY WITH TANK HOLDING DEVICE. The dolly of application Ser. No. 803,254 is provided with a frame constructed of formed and stamped metal elements to which separate brackets for mounting swivel-type wheel units are secured.

In accordance with the instant invention, a dolly is constructed with a base consisting of two elongated plastic elements that are interengaged in a T-configuration, with one element constituting the crossarm and the other element constituting a leg which extends from the center of the crossarm and at right angles thereto. The connection between the leg and crossarm permits limited adjustment between these elements so that the drum diameter need not have a close tolerance. A metal rod constituting an axle extends lengthwise through the crossarm and mounts wheels at opposite ends thereof. At the end of the leg remote from the crossarm there is a well that receives the stem of a swivel-type wheel unit. The front or top of the base is provided with three slots, two being at opposite enlarged ends of the crossarm and the third being at the enlarged end of the leg remote from the crossarm. These slots receive the peripheral bead at the bottom of the drum, which bead is held in the slots by screws that are mounted to the base, with portions of the screw heads overlapping the bead.

Accordingly, the primary object of the instant invention is to provide an inexpensive dolly that is readily securable to a drum which is standing on end.

Another object is to provide a dolly of this type that includes a load carrying base constructed of interengaging plastic elements.

Still another object is to provide a dolly of this type in which there is a wheel axle that extends longitudinally through one of the plastic elements and is disposed for direct support of the drum.

A further object is to provide a dolly of this type in which the base is provided with an integrally formed well that receives the stem of a swivel-type wheel unit.

A still further object is to provide a dolly of this type that is adjustable for use with drums of different diameters that fall within a reasonably large range of dimensional variation.

The foregoing objects, as well as other objects of this invention will become readily apparent reading the following description of the accompanying drawings in which:

FIG. 1 is a perspective of a vacuum cleaner mounted on a dolly constructed in accordance with teachings of the instant invention;

FIG. 2 is a perspective of the dolly of FIG. 1;

FIG. 3 is a top or front view of the dolly base;

FIG. 4 is a fragmentary cross-section illustrating a swivel-type wheel unit mounted to the base;

FIG. 5 is a fragmentary rear or back view of the base in FIG. 4;

FIG. 6 is a fragmentary top view illustrating securement of the drum to the base at one enlarged end of the base crossarm;

FIG. 7 is a partial cross-section illustrating securement of the vacuum cleaner drum to one enlarged end of the crossarm base;

FIG. 8 is a partial cross-section illustrating securement of the vacuum cleaner drum to the enlarged end of the base leg;

FIG. 9 is a rear elevation of the base leg;

FIG. 10 is a fragmentary portion of the base leg taken through section line 10--10 of FIG. 9, looking in the direction of arrows 10--10;

FIG. 11 is an elevation of the base leg, looking in the direction of arrows 11--11 of FIG. 10 toward the cutaway end of the base leg;

FIG. 12 is a front elevation of the base leg end remote from the base crossarm;

FIG. 13 is a partial section taken through line 13--13 of FIG. 12, looking in the direction of arrows 13--13;

FIG. 14 is a top plan or front view of the crossarm;

FIG. 15 is a partial longitudinal section of the crossarm taken through line 15--15 of FIG. 14, looking in the direction of arrows 15--15;

FIG. 16 is an end view of the crossarm, looking in the direction of arrows 16--16 of FIG. 15;

FIGS. 17 and 18 are partial cross-sections of the crossarm taken through the respective lines 17--17 and 18--18 of FIG. 14, looking in the direction of the respective arrows 17--17 and 18--18;

FIG. 19 is a bottom or rear view of one end of the crossarm;

FIGS. 20 and 21 are cross-sections taken through the respective lines 20--20 and 21--21 of FIG. 19, looking in the directions of respective arrows 20--20 and 21--21;

FIG. 22 is a fragmentary elevation of the crossarm looking in the direction of arrows 22--22 of FIG. 19.

Now referring to the drawings, in which FIG. 1 illustrates tank 12 of vacuum cleaner 11 mounted on dolly 10 which is constructed in accordance with teachings of the instant invention. In a manner known to the art, tank 12 is provided with cylindrical side wall 14. Motor-blower assembly 15, removably held in operative position by a plurality of manually operable latches 16, normally closes the upper end of the tank 12. The lower end of tank 12 is closed by recessed disc 17, having a reversely curled peripheral edge that constitutes bead 18 which surrounds side wall 14 at the bottom edge thereof. Dolly 10 includes generally T-shaped base 20 formed through the cooperation of crossarm 21 and leg 22. The latter extends from the center of crossarm 21 and at right angles thereto. Both elements 21 and 22 are constructed of a relatively hard, rugged plastic such as foamed high density polyethylene.

Metal rod 23 extends longitudinally through crossarm 21 and constitutes a fixed axle for relatively large wheels 24, 24 that are mounted to opposite ends of rod 23 just outboard of the enlarged ends of crossarm 21, with push-type cap nuts 26, 26 retaining wheels 24, 24 mounted on axle 23. Swivel-type wheel unit 27 is mounted to leg 22 at the enlarged end thereof disposed remote from crossarm 21. Wheel unit 27 includes wheel 28 rotatably mounted on horizontal pin 29 that extends between the arms of U-shaped bracket 31. Stem 32, constituting a swivel axis for unit 27, extends upward from the web of bracket 31 into plastic insert 33. The latter is disposed within recess or well 34 in the bottom of leg 22, being captured by the head of screw 36 (FIG. 4) that is threaded into leg recess 37 (FIG. 9).

With particular reference to FIGS. 9-13, it is seen that a major portion of leg 22 is of T-shaped cross-section, as indicated by hatched section 38 in FIG. 11. For a reason which will hereinafter be explained, this T cross-section 38 extends to the end of leg 22 that is remote from wheel 28. The upper surface of leg 22 at the enlarged end thereof where wheel 28 is mounted, is provided with transverse arcuate groove 41 that receives bead 18 at the lower edge of tank 12. Spaced with respect to the length of groove 41 and disposed immediately to the outboard side thereof are two apertures 42, each of which receives a hex-head screw 43 (FIG. 6) entered through the top of hole 42. Screw head 44 is disposed within recess 46 which is shaped to prevent rotation of screw 43. A portion of head 44 engages bead 18 along the upper edge thereof to capture the latter within groove 41. Screw 43 is held in position by nut 47 that is threadedly mounted thereon at the rear of leg 22, with washer 48 being interposed between nut 47 and a bottom surface of leg 22. In a similar manner, tank 12 is secured to opposite enlarged ends of crossarm 21.

That is, the upper surface of crossarm 21 at each enlarged end thereof is provided with an arcuate groove 51 that is open at the top for the length thereof. Through aperture 52 is formed along the outboard edge of groove 51 to receive an additional holding screw 43. Head 44 of each additional screw 43 is received within a partially hexagonal depression 56 and overlies bead 18 to block the latter from leaving groove 51. Short transverse projection 61, at the center of base member 21, is provided with T-shaped depression 62 that complements T-shaped portion 38 of leg 22 (FIG. 13). The latter at its free end is entered into complementary 62 so as to permit base members 21 and 22 to slide relative to one another in a manner such that there is limited adjustment therebetween, as indicated by arrow A in FIG. 2. This adjustment enables dolly 10 to be fastened readily and securely to tanks 12 that fall within an acceptable relatively wide range of dimensional variation.

Crossarm 21 also includes longitudinal passage 65 which is open at the top thereof for the major portion of its length. This top opening to passage 65 extends from one groove 51 to the other groove 51. Each end portion of passage 65 outboard of grooves 51 is open at the bottom thereof. In this way axle rod 23 that extends through passage 65 is retained against transverse movement by crossarm 21. The lower portions of grooves 51 communicate with passage 65 so that bead 18 at the lower edge of drum 12 rests directly against rod 23. This direct contact between axle 23 and the lower edge of bead 18 serves to protect the plastic elements of dolly 10 from severe impacts such as those occurring when descending stairs. Depression 62 communicates with passage 65 at the center thereof and permits T-shaped portion 38 of leg 22 to extend over axle rod 23.

Dolly 10 is mounted to tank 12 by locating leg 22 so that swivel unit 27 is under inlet 99 and then tightening nuts 47 on two screws 43 carried by leg 22. Thereafter, crossarm 21 is positioned by mating same with the end of leg 22 remote from wheel 28 and then securing the latter to drum 12 by tightening nuts 47 on the other two screws 43. The upper surface 98 of leg 22 is adjacent the recessed bottom surface provided by disc 17, and the end of leg 22 remote from wheel unit 27 is captured between drum closure disc 17 and crossarm 21.

Although the present invention has been described in connection with a preferred embodiment thereof, many variations and modifications will now become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.