Title:
Hand truck with stair climbing shoe
United States Patent 2459275


Abstract:
This invention relates to a hand truck and particularly to a mechanism incorporated therein to not only protect the forward edges of the treads upon stairways, but also to facilitate the lifting of the truck from one tread to the next. A primnary 6bject of the invention is to provide a truck...



Inventors:
Gates, John C.
Application Number:
US77645947A
Publication Date:
01/18/1949
Filing Date:
09/27/1947
Assignee:
Gates, John C.
Primary Class:
Other Classes:
16/33, 280/10, 280/47.27
International Classes:
B62B5/02
View Patent Images:
US Patent References:
2171889Boat trailer apparatus1939-09-05
1965944Truck construction1934-07-10
1802437Bag holder1931-04-28



Description:

This invention relates to a hand truck and particularly to a mechanism incorporated therein to not only protect the forward edges of the treads upon stairways, but also to facilitate the lifting of the truck from one tread to the next.

A primnary 6bject of the invention is to provide a truck of the nature for the purposes indicated ifi whikh the mechanism is exceedingly simple and automatic in repositioning itself. A further impdrtant object is to provide such a structure with a minimum number of parts assembled in an unique manner to be durable over long periods of usage and capable of being produced at a relatively low cost.

These and other important objects of the invention will become apparent to those versed in the art in the following description of one particular form of the invention as illustrated in the accompanying drawing, in which Fig. 1 is a view in side elevation of the structure embodying the invention; Fig. 2, a view in front elevation; Fig. 3, a view in top plan; Fig. 4, a view in side elevation in a partially raised position; Fig. 5, a detail in side elevation and partial section on an enlarged scale of the anti-frictioi shoe; Fig. 6, a sectior on an enlarged scale on the line 6-6 in Fig. 1, and Fig. 7, a longitudinal section on the line 7-7 in Fig. 6.

Like characters indicate like parts throughout the several views in the drawing.

In the present form of the invention, I bend ' a piece of tubing generally designated by the numeral 10, to have a cross bar portion 11 from the ends of which are downwardly turned rails 12 and 13, and from the lower ends of which the tubing is bent to form the forwardly extending 4 legs 14 and 15 respectively. Across the upper sides of these legs 14 and 15 is mounted any suitable supporting structure herein shown as consisting of a pan 16 which is secured to the legs 14 and 15 preferably in a detachable manner, such 4 as by the bolts 17. An axle 18 is carried across the undersides of the legs 14 and 15 close to the rear ends thereof. This axle 18 is fixed against rotation by means of the straps 19, one on each outer side respectively of each leg 14 and 15 5c these straps 19 being connected directly to the pan 16. On the outer ends of the axle 18 are rotatably fixed wheels 20 respectively.

On each of the standards 12 and 13 adjacent the lower ends thereof is mounted an anti-friction shoe designated generally by the numeral 21 in each instance, the shoes being identical in construction one to the other.

The'shoe 21 in each instance is formed out of h sheet metal arched to form an upper portion 12 through which the leg 12 or 13 as the case may be, may slidingly extend. From each side of this arched portion 22, the metal is carried downwardly or backwardly from the leg 13 for example, Sby a wall 23 on the one side and 24 on the other.

These walls 23 and 24 have inwardly turned legs 2s alid 26 one extending toward the other in the same plane. From the inner end of the leg 25, the metal is turned back toward the standard 13, Fig. 6, a short distance by a length 27 then is curved around in an arcuate manner toward the wall 23 to form the cupped length 28. In like manner the metal extends from the end of the leg 26 in contact with the length 27 by a portidn 29 and then curves outwardly toward the wall 26 by a cupped length 30.

A number of through rivets 31, herein shown as four in number, are carried through the side walls 23 and 24 and also the cupped walls 28 and 30, spaced from the legs 25 and 26 toward rail t1, Fig. 6, a distance to position those rivets 31 substantially centrally of the cupped portions 28 and 30.

These rivets 31 are employed to hold the wall portions 27 and 29 in contact one with the other whereby a groove is formed and maintained between the cupped portions 28 and 30 to retain therein a number of balls 32, herein shown as three in number. The portions 28 and 30 are Surved to follow generally the curvature of the balls 32, but terminate by their inner ends a distance from the rail 13 in order that the balls 32 may be held by the members 28 and 30 in rolling contact with the rail 13 and the bottom of the groove at least by those members 28 and 30.

As indicated in Fig. 7, one ball 32 is spaced between each of the adjacent rivets 31 so that the permissible travel along the members 28 and 30 is limited by the respective balls 32 coming into contact with the rivets 31. As indicated in the drawing, the length of the arch portion 22 is less than the lengths of the walls 23 and 24. This difference in lengths is provided in order to permit the shoe 21 to travel along the rail 13 (or rail 12) downwardly to have a considerable portion of the walls 23 and 24 below the junctures of the legs 14 and 15 with their standards 12 and 13, this degree of travel being indicated by comparison with the positions of the shoes 21 in Fig. 1 and Fig. 4.

The shoes 21 are normally positioned yieldingly in upper positions as indicated in Figs. 1 and 2.

This elevation of the shoes 21 above the legs 14 and 15 is determined in relation to the diameter of the wheels 20 to have the back side of the shoe in each instance consisting of the leg portions 25 and 26 strike the outer corner of the tread of a stairway, Fig. 1, indicated by the dash line position. Then upon pulling the truck upwardly as indicated in Fig. 4, the shoes 21 will remain ] against the tread corner designated by the numeral 33 by pressure thereagainst and the standards 12 and 13 will be pulled upwardly in rolling contact over the balls 32 to allow the wheels 20 to be finally rolled back on the top of that tread whose corner 33 is then contacted by the shoes 21. Once the wheels 20 are back on that tread, the shoes 21 are automatically returned to their uppermost positions.

The means for creating this automatic return of the shoes 21 consists of two opposed springs 34 and 35 carried within the walls 23 and 24.

Spring 34 has its lower end engaged with the rail S3 and its upper end engaged with the upper portion of the wall 24, Fig. 7. The spring 35 has its upper end fixed to the rail 13 and its lower end fixed to the lower portion of the wall 23. Thus when the shoe 21 is relatively pulled downwardly along the standard 13, the spring 35 is extended in length whereas the spring 34 is decreased in length so that upon release of the shoe 21 permitting it to be free to travel along the rail 13, the spring 35 will carry the shoe 21 upwardly until the pulls of the two springs 34 and 35 are substantially balanced. It is to be understood that both springs 34 and 35 are initially placed under tension by stretching them between their end engagements. The upper spring 34 is employed to limit the upward travel of the shoes 21 along the rail 13 so that it will be normally properly positioned for contact with the corner 33.

While I have herein shown and described my invention in the one particular form, it is obvious that structural changes may be employed without departing from the spirit of the invention and I therefore do not desire to be limited to that precise form beyond the limitations which may be imposed by the following claims.

I claim: 1. A hand truck comprising a wheel mounted frame having a pair of side rails normally upwardly extending, and a shiftable shoe on each of said rails, each shoe comprising a box-like member encircling the rail to have a forward side slidably engaging the rail and a rear or under bearing side, and a spring interconnecting said rail and said member in a manner to increase the tension on the spring upon relative downward travel ol the shoe along the rail, whereby.the spring wil. tend to return the shoe to an upper normal position of rest.

2. A hand truck comprising a wheel mounted frame having a pair of side rails normally upwardly extending, and a shiftable shoe on each of said rails, each shoe comprising a box-like member encircling the rails to have a forward side slidably engaging the rail and a rear or under bearing side, and a spring interconnecting said rail and said member in a manner to increase the tension on the spring upon relative downward travel of the shoe along the rail, whereby the spring will tend to return the shoe to an upper normal position of rest; said member having a L5 groove between the rail and said underside; and ball bearings in said groove, between it and the back side of said rail.

3. A hand truck comprising a wheel mounted frame having a pair of side rails normally upwardly extending, and a shiftable shoe on each of said rails, each shoe comprising a box-like member encircling the rails to have a forward side slidably engaging the rail and a rear or under bearing side, and a spring interconnecting said rail and said member in a manner to increase the tension on the spring upon relative downward travel of the shoe along the rail, whereby the spring will tend to return the shoe to an upper normal position of rest; said member having a groove between the rail and said underside; and ball bearings in said groove; between it and the back side of said rail; and a second spring interconnecting said rail and said member normally oppositely balancing the pull of said first spring. 4. A hand truck rail bearing shoe comprising a housing having an upper arched portion to slide along said rail, from the sides of which housing side walls extend; a floor between those walls; a ball bearing carrying grooved member mounted over the floor and between the wall; balls in said member; a coil spring fixed to said housing and extending internally thereof along one of said walls; said floor being formed in two parts, each part consisting of a leg inturned from the said walls one leg toward the other; and said groove member being formed by two arcuate parts, one part turned from one of said legs and the other part from the other leg.

JOHN C. GATES.

REFERENCES CITED The following references are of record in the file of this patent: UNITED STATES PATENTS Number 1,802,437 1,965,944 2,171,889 Name Date McHugh ----------- Apr. 28, 1931 Lea -------------- July 10, 1934 Payson ------------- Sept. 5, 1939