US2246628A - Mechanic's creeper - Google Patents

Description

June .24, 1941. J. H. HECKMAN MECHANIGYCREEPER Filed Feb; 10, 1941 2 Sheets-Sheet 1 June 24, 1941. J. HECKMAN 2,245,628

MECHANIC S CREEPER Filed Feb. 10, 1941 2 Sheets-Sheet :2

7 l c Y I I II i a Patented June 24, 1941 UNlTED STAT Es PATENT OFFICE MEonsNIcs CREEPER Joseph H. Heckman, Chicago, Ill. Application February 10, 1941, Serial No. 378,292 4 claims. (Cl. 280 -615) This invention relates to a mechanics creeper,

and more particularly to a creeper of anim proved type such that it is not injured by excessive overload, as when itis run over by the wheel ofacar. i

One feature of this invention is that it provides an exceptionally sturdy and satisfactory creeper; another feature of this invention is, that its body is of sufficient strength to resist anticipated overloads, as the wheel of an automobile, and provision is made for protecting the supporting Wheels of the creeper under such. conditions; yet another feature of this invention is that under normal usage the creeperis asfully and easily maneuverable as the conventional creeper, and capable of passing over minor obstructions, as a crack in the floor or a hand wrench; other features and advantages of this, invention will be apparent from the following specification and the drawings, in which: i i

Figure 1 is a topplan view of a mechanics creeper embodying my invention; Figure 2 is a side elevation of the creeper shown in Figure l, partly broken away; Figure 3 is aviewsimilar to that of Figure 2, but showingthe creeper under abnormal load, as the wheel of a car; Figure 4 is an end elevation of the creeper shown in Figure 2; Figure 5 is a bottom plan View of the creeper; Figure 6 is a detail fragmentary bottom plan view of the mounting arrangement of one of the casters; and Figure '7 is a fragmentary sectional view along the line 1-1 of Figure 6.

Mechanics creepers, low flat movable supports permitting a mechanic to work convenientlyin a reclining position beneath an automobile, have been known and used for some time. These creepers have been open to several serious objections, however. One of these objections is that, where conventional small casters are'used at the four corners of the creeper, accidental overloads (such as those imposed by the wheel of an automobile) result in either smashing the body of the creeper or destroying one or more'of the casters.

In order to keep the creeper close enough to the floor on which it is to be used, these pivotally mounted wheels or casters must be quite small, and their service life is generally very short. In the conventional creeper, where four casters are rigidly mounted at the four corners of the body of the creeper, the service life of the casters is such that they generally must be replaced about once a month in a garage where a creeper is given the customary amount of use.

I have heretofore met this problem of caster breakage by the use of relatively large wheels of considerable strength, as dis-closed in my Patent No. 2,148,199, which issued to me on February 21, 1939. Such wheels were not pivotally mounted with respect'to the body of the creeper, however, and certain mechanics prefer a creeper with casters, so that the creeper is fully and freely movable in any direction at any time.

My present invention retains this complete freedom of movement, yet avoids breakage of the creeper body or casters upon accidental overload. I have accomplished this by mounting the casters in such a Way that they are yieldable under overload. That is, under normal usage the casters carry the weight of the creeper and the mechanic lying thereon, and maintain a clearance between the creeper body and the floor which is in the neighborhood of one-half inch; but under abnormal overload, as the wheel of a car, the casters yieldand retreat into recesses provided therefor in the [creeper body, so that the creeper body itself comes into contact with the floor to withstand the abnormal load.

In theparticular embodiment of my invention illustrated herewith the creeper comprises a body portion having side frame members or bars l0, and Il. These are rigidly held together at appropriate intervals by transverse cross members fastened beneath the side frame members. These cross members are here shown as four in number, and identified as [2, 13,14 and I5. The bed of the creeper, designed to support the reclining mechanic, is of thinner material carried by the cross members, and lying between the side frame members. This may be of plywood, for example, and is here identified as It. The body'is also preferably provided, at one end, with a head rest or cushion l1.

The creeper body is supported, in normal usage, by four pivotally mounted wheels or casters here identified as [8, I9, 23 and'2l. These casters are so mounted that, under no load or the normal load of a mechanic, the position of the creeper with respect to its supporting surface is as illustrated in Figure 2. But the mounting is yieldable, so that if the creeper is subjected to an abnormal overload, as by being run over by the wheel 22 of a car, the relation of the creeper to its supporting. surface is as illustrated in Figure 3, the abnormal overload now being distributed over the entire surface or underside of the transverse members l2, l3, l4 and i5. It will be understood, of course, that if the wheel of the automobile ran over the extreme end of the creeper only the casters on that end might yield, and only the transverse member on that end come into engagement with the floor. In any event, however, abnormal overloads do not have to be carried by the casters, but are instead supported directly by the body. The frame and transverse members of the body are preferably of hardwood, of considerable strength. The proportion of the various parts can be readily ascertained when it is understood that the .creeper shown is about three feet long and a little less than one and one-half feet wide. The mounting of each' of the casters is identical, and for convenience of description only one will be considered in detail. Referring more particularly to Figures 6 and 7, it will be seen that the frame member II is provided near its end with a recess which may be termed keyholeshaped. This recess comprises a circular portion 23 and an extending portion 24. The'diarne ter of the portion 23 of the opening is a little greater than the outside radius of the circle of the swivelling caster wheel I8; and its depthis such as to normally partly receive the caster wheel mounting, with sufiicient reserve or normally unused depth to permitthe caster wheel and its mounting to move up into the recess until the underside of the transversemembersof the body contact the floor on which the creeper rests.

The" yieldable mounting is here shown in a form which I have found practicable; although it will be understood that other equivalent'yieldi able mountings for the caster wheel could be used. In my embodiment of the invention disclosed herewith a leaf spring is used as a sup port for the caster. This leaf spring may be a portion of a conventional automobile spring leaf, fastened at one end, as by the bolts 25 and 26, to the body of the creepers; and carrying at its other end the caster (8'. The caster plate may be fastened to this end of the leaf spring,

here indicated as 21, by riveting as shown here,

or by bolts. It will be seen that the leaf spring 2'! lies with the center portion of its body in the extended portion 24 of the recess in the frame member, with its outer end lying just within the circular recess 23.

Casters of the kind which I have used in a practicable embodiment of my invention have a strength in the neighborhood of 250 pounds each. That is, the caster wheels and their swivel mounting will withstand up to 250 pounds before breaking or becoming so deformed as to be of no further use. In conjunction with these casters I have chosen a leaf spring of such a strength that 50 or 60 pounds of weight per caster can besupported before there is any noticeable yield orthe spring; and thereafter the spring yields until; when there is about 150 pounds weight on any one caster and its supporting spring,.the' caster and its mounting have retreated to the position shown in dotted lines in Figure 7, so that any further load is taken directly by the transverse frame members. With this construction the nor-- mal weight of a mechanisc, distributed over the four casters, results in no appreciable yield of their mounting, and the under surface of the creeper body is maintained with a clearance of about one-half inch from the floor. Under abnormal overload, however, the caster wheels retreat or yield to transfer the load to the underside of the transverse frame members. This transfer of load takes place long before the breaking point of the casters themselves is reached, so that the casters are never broken or deformed. It is obvious that this provides a very rugged creeper of the caster type, which will protect the casters against destruction from overloads.

While I have described and shown certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arra'ngement may be made without departing from the, spirit and scope of the invention as disclosed in the appended claims,

1. A mechanics creeper of the character described, including: a body adapted to support a person in reclining position, the entire body being very close to the surface on which it is adapted to'be supported and having a plurality of recess'es in its under side; wheels for carryingthe body, said wheels normally lying partially within said recesses; and mounting means connecting the wheels to the body, the wheels and mounting means being entirely beneath the body, said mounting means being yieldable and of sufficient strength to maintain said body spaced from the supporting surface under normal load but sufficien'tly yieldable that the wheels move further into said recesses to permit contact of said body with said surface under abnormal load.

2. A mechanics creeper of the character described; including: a body adapted to support a.

3 person in reclining position, the body comprising side frame members of substantial thickness having recesses in their under sides near their ends, and an intermediate supporting portion of lesser thickness; casters for carrying the body, said casters normally lying partially within said recesses; and spring means for mounting said casters' on the under side of said body, said means being of sufficient strength to maintain said body spaced from the supporting surface under normal load but sufiiciently yieldable that the casters move further into said recesses to permit contact of said body with said surface under abnormal load, the casters and spring means being at all times entirely beneath the body.

3. Apparatus of the character claimed in claim 2, wherein the mounting means for each caster is a leaf spring having one end connected to the caster and the other end connected to the under side of the body.

4. A mechanics creeper of the character described, including: a body adapted to support a person in reclining position, the entire body being very close to the surface on which it is adapted' to be supported; and wheels beneath the body for carrying it, each wheel being mounted on a member movable with respect to the body and in turn yieldably mounted thereon, portions of the body completely overlying the wheels and mounting and projecting down toward said surface to contact it, under abnormal load, before the yield of the mounting has reached its limit.

JOSEPH H. HECKMAN.

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