US2843392A - Stands or tables having retractable casters - Google Patents

Description

STANDS OR TABLES HAVING RETRACTABLE CASTERS Filed Feb. 11, 1957' W. SIMPKINS July 15, 1958 2 Sheets-Sheet 1.

FIGI.

INVENTOR WILLIAM SIMPKINS A TTORNEYS 2,843,392 STANDS OR TABLES HAVING RETRACTABLE CASTBRS Filed Feb. 11; 1957 W. SIMPKINS July 15, 1958 2 Sheets-Sheet 2 FICA.

I INVENTOR WILL/AM 5IMPKIN5 ATTORNEYS 2,843,392 Patented July 15, 1958 STANDS R TABLES HAVING RETRACTABLE CASTERS William Simpkins, St. Louis, Mo. Application February 11, 1957, Serial No. 639,529

6 Claims. (Cl. 280-44) This invention relates generally to stands or tables and more particularly to stands or tables having retractable casters.

' It is an important object of the present invention to provide a stand or table of the type described which includes improved means for raising it onto and lowering it from its casters.

Another important object is achieved by the provision of improved means for selectively maintaining the mechanism in caster-projecting position.

Other important advantages are realized by a resilient spring operatively connected to mechanism for causing the caster projection, the spring being adapted to faciliate raising of the stand onto its casters and to cushion the lowering movement of the stand from such casters.

Still another important objective is realized in providing a caster-actuating mechanism that is simple and dura ble in construction, efiicient and positive in operation, and economical to manufacture.

The foregoing and numerous other objects and advantages of the invention will more clearly appear from the following detailed description of a preferred embodiment, particularly when considered in connection with the accompanying drawings, in which:

Fig. 1 is a front elevational view of the stand with the casters retracted;

Fig. 2 is a side elevational view of the stand shown in Fig. 1;

Fig. 3 is an enlarged fragmentary View of one end frame as seen along line 3-3 of Fig. 2, showing the mechanism for raising the stand on its casters;

Fig. 4 is a side elevational View of the end frame and mechanism shown in Fig. 3, the casters being shown in retracted position, and

Fig. 5 is a side elevational view of the end frame and mechanism shown in Fig. 4, but showing the casters in projected position.

Referring now by characters of reference to the drawings, it is seen that the stand is comprised of a pair of end frames generally indicated at and 11 in Fig. 1, each end frame consisting of a pair of upstanding legs 12 interconnected at the top by a horizontal cross piece 13, Fig. 2, and interconnected at the bottom by a cross piece 14. The end frames 10 and 11 are connected at the top by horizontal cross pieces located at the front and back of the stand assembly. It will be noted that cross pieces 13 and 15 form a support for a tray top. A lower cross piece 16 (Figs. 1 and 3) joins one of the pair of legs 12 joined at their tops by one of cross pieces 15. The other pair of legs 12 is not directly joined by a lower cross piece, leaving an open well bridged at the top by a cross piece 15 as shown in Fig. 1, into which the legs of a person sitting at the stand may project.

The legs 12 are equipped with feet indicated at 17 having an uppermost square-sectioned sleeve portion 18 and an open bottom cup portion 19 that is adapted to seat on a subjacent surface such as a floor as shown in Figs. 1, 2

and 4. The feet 17 are secured by bolts 20 to the lower ends of legs 12.

Slidably received in foot sleeve portion 18 is a square bearing block 21 having a portion extending above sleeve portion 18. The bearing blocks 21 are drilled to receive and retain the shanks of casters 22.

A cross rod 23 is rotatively mounted on and bridges lower cross pieces 14, the rod 23 being of square section 'for reasons which will later appear. Attached to cross rod 23 and located between cross pieces 14 is a treadle 24 adapted to be manipulated by the foot of the person utilizing the stand. A brace 25 is secured by bolts 26 to the top of cross pieces 14 in the region immediately overlying cross rod 24, the brace 25 engaging treadle 24 to limit rotation of rod 23 as the frame is lowered from casters 22 as is more clearly shown in Fig. 4 of the draw- Of course, the brace 25 serves in addition to reenforce the connection of end frames 10 and 11, and hence provides a more rigid structure.

Attached by pivot pins 27 to each of cross pieces 14 is a pair of arms 30 and 31. The outer ends 32 of arms 30 and 31 are reduced to interfit compatible sockets 33 provided in the uppermost ends of bearing blocks 21. The inner ends of arms 30 and 31 overlap, such inner ends being provided with aligned slots 34 through which a pivot pin 35 is received. The pin 35 and coacting slots 34constitute a slidable pivot connection for the inner ends of arms 30 and 31.

A cam element 36 is mounted on each cross piece -14 by a pivot pin 37. The cam element 36 includes a hearing portion 40 spaced from the pivot pin 37 and adapted to engage one arm 30 along the lower margin of its inner end. A shoulder 41 is provided on bearing portion 40 to assure engagement of bearing portion 40 with arm 30 upon rotation of cam element 36. The casterprojecting mechanism further includes a first link element 42 attached at one end and rotatable with cross rod 23, and pivotally connected at the other end to a second link element 43, the second link element 43 being in turn pivotally connected to cam element 36 at a point spaced from the pivot pin 37 and the bearing portion 40.

In operation, assuming the stand to be resting on its feet 17, the inner ends of arms 30-31 are down, the outer ends 32 up, and the caster blocks 21 are raised. The cam elements 36 are arranged so that the bearing portions 40 are located to the left of the vertical passed through pivot pins 37 as is shown in Fig. 4, such at-rest position of cam elements 36 being determined by the abutment of treadle 24 with brace 25 when in a raised position.

To raise the stand onto the casters 22, treadle 24 is simply depressed, which rotates cross rod 23 and attached link elements 42. Such action causes rotation of cam elements 36 about their pivot pins 37 through interconnecting links 43. As cam elements 36 are rotated clockwise (Fig. 4) the bearing portions 40 engage arms 34) and operate through the slidable pivot connections 34-35 to raise the inner ends of both arms 30-31, and hence depress bearing blocks 21 and raise the stand. As cam elements 36 rotate, the bearing portions 40 pass through the vertical determined by pivot pins 37, and locate on the other side of such vertical in caster-projecting position as is clearly shown in Fig. 5. This caster-projecting position of cam elements 36 is determined by a stop member 44 on each cross piece 14 located to engage first link element 42. Because bearing portions 40 engage arms 30-31 at points located at the right hand side (Fig. 5) of a vertical plane passed through pivots 37, the weight of the stand is transmitted by the arms Bil-31 to bearing portions 40, and hence transmitted by cam elements 36 and linkages 42-43 to the stop members 44. The mech- 3 anism above described provides a positive retention of the stand in the raised position.

A tension spring 45 is attached to each cross piece 14 and is attached to first link element 42, the springs 45 tending to rotate cam elements 36 to the caster-projecting position through forces applied to the interconnecting links 42-43. It is seen that this action of springs 45 facilitates lifting of the stand onto the casters 22.

To lower the stand from casters 22, the treadlc 24 is lifted which rotates rod 23 and connected link elements 42, and hence causes rotation of cam elements 36 in a clockwise direction to the position shown in Fig. 4. The stand is thus permitted to rest on its feet 17. It will be particularly noted that since springs 45 tend to rotate cam elements 36 to the caster-projecting position, the lowering movement of the stand will thus be cushioned by such springs 45 which serve in a sense as a shock absorber.

Although the invention has been described by making detailed reference to a single preferred embodiment, such detail is to be understood in an instructive, rather than in any restrictive sense, many variants being possible within the scope of the claims hereunto appended.

I claim as my invention:

1. A stand of the character described comprising a pair of end frames having legs with feet and casters mounted on said legs for projection beyond said legs, a cross piece mounted on each end frame between said legs, a rod element mounted on said cross pieces, a casterprojecting mechanism on each end frame including a pair of arms pivoted on the cross piece, said arms being connected at their outer ends to said casters and overlapping at their inner ends, means connecting said inner ends, a cam element, pivot means mounting the cam element to said cross piece, a first link element attached to said rod element and rotatable therewith, a second link element pivotally connected to said first link element and to said cam element,'the cam element engaging said arms to project said casters upon rotation of said rod element, and stop means engaging one of said elements to limit rotation of said cam element and to maintain the cam element in a caster-projecting position.

2. The combination and arrangement of elements as recited above in claim 1, but further characterized in that the cam element in the caster-projecting position engages the arms at one side of the vertical through said pivot means.

3. The combination and arrangement of elements as recited above in claim 2, but further characterized by the provision of a resilient means connected to one of said elements tending to urge said cam element to the casterprojecting position, the resilient means serving to facilitate raising the frames onto said casters and to cushion the movement of said frames from said casters.

4. The combination and arrangement of elements as recited above in claim 2, but further characterized by the provision of a slidable pivot connection between the overlapping inner ends of said arms, and that the cam element engaging one of said arms upon rotation to the caster-projecting position.

5. A stand of the character described comprising a pair of end frames having legs with feet and casters mounted on said legs for projection beyond said legs, a

' cross piece mounted on each end frame between said legs,

a rod element mounted on said cross pieces, a casterprojecting mechanism on each end frame including a pair of arms pivoted on the cross piece, said arms being connected at their outer ends to said casters and overlapping at their inner ends, a slidable pivot connection between the overlapping inner ends, a cam element, pivot means mounting said cam element to said cross piece, a first link element attached to said rod element and rotatable therewith, a second link element pivotally connected to said first link element and to said cam element in spaced relation to said pivot means, the cam element engaging one of said arms to project said casters upon rotation of said rod element, the said cam element in the caster-projecting position engaging the arms at one side of the vertical through said pivot means, and stop means engaging said first link element to limit rotation of the rod element and to maintain the cam element in said caster-projecting position.

6. The combination and arrangement of elements recited above in claim 5, but further characterized by the provision of a tension spring attached to said cross piece and attached to said first link element, the tension spring tending to urge said cam element to the caster-projecting position so as to facilitate raising the frame onto said casters and to cushion lowering movement of the frame from said casters.

Allen Feb. 2, 1875 Shampaine Dec. 5, 1950

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