Elevationally Adjustable Folding Stage

The present invention pertains to improvements in foldable stages and more particularly to an improved and simplified elevationally adjustable folding stage.

Foldable portable stages have become very popular and widely used in multi-purpose rooms or areas wherein differing use requirements dictate rapid setup and take-down capability of the stage. One example of a prior art folding mobile stage is found in U.S. Pat. No. 3,351,029 issued to R. C. Bue.

It has been recognized that even greater versatility of use could be achieved if a simple and convenient elevational adjustment could be provided for a portable folding stage. One type of elevationally adjustable foldable stage is disclosed in copending patent application Ser. No. 626,979 by Kermit H. Wilson, Richard C. Bue and Ronald R. Carlson, filed Oct. 29, 1975 now U.S. Pat. No. 4,026,221, issued May 31, 1977. The present invention provides yet another means for elevational adjustment of folding stage that is somewhat simpler in construction and is easier to adjust in height.

The present invention provides a simple and convenient elevational adjustment feature for a foldable stage of the type having first and second stage surface members, first and second main support legs interconnected to form a base frame for supporting the stage in its folded position, and means for pivotally mounting the first and second stage surface members to the base frame for pivotal movement between a storage position in which the members are generally vertically positioned above the base frame, and an operable position in which the stage members are horizontally positioned to define a common stage surface. Pairs of outer legs are attached to each of the stage surface members at their opposite ends, remote from the pivotal connection to the base frame, and means are provided for adjusting the length of said outer legs. Auxiliary support legs are mounted to the underside of the first and second stage surface members relatively adjacent the ends thereof which are pivotally connected to the base frame. The auxiliary legs are adjustable between a first inoperative position and a second operable position in which they extend from the stage surface members a distance greater than that of the main support legs. In a preferred embodiment, the feet of the auxiliary legs have floor contact portions which extend towards the center of the stage for providing additional support for the center of the stage in its elevated position, and have a curved portion to facilitate in a rocking or pivoting motion thereabout so as to make easier and more convenient the transition of the stage from its folded position into its operative, extended height position.

In the drawing, FIG. 1 is a view in side elevation, portions thereof broken away for clarity, of an elevationally adjustable folding stage according to the present invention, one half thereof being indicated in raised position for illustrative purposes;

FIG. 2 is a view in side elevation of the folding stage of FIG. 1 in a storage position;

FIG. 3 is an enlarged fragmentary detail in top plan of a portion of FIG. 1, portions thereof removed for purposes of clarity;

FIG. 4 is an enlarged view in side elevation of a portion of the elevationally adjustable folding stage of FIG. 1;

FIG. 5 is a diagrammatic view in side elevation illustrating the folding and elevationally adjustment according to the present invention;

FIG. 6 is a view in side elevation of a stage in storage position having auxiliary legs with modified configuration; and

FIG. 7 is a view in side elevation of the stage of FIG. 6, portions thereof broken away, with the stage in elevated, operable position.

Although the elevationally adjustable feature of the present invention could be used with many types of folding stages, in the presently preferred embodiment the invention is used in conjunction with the prior art type of folding stage disclosed in U.S. Pat. No. 3,351,029; and the preferred embodiment as illustrated herein shows the elevationally adjustable feature of the present invention applied to that type of folding stage.

The stage of FIG. 1 comprises a pair of stage surface members 10 and 11. In FIG. 1, the stage is shown in its open or operable position in which the stage surface members 10 and 11 are positioned adjacent each other to form a continuous stage surface. Stage member 11 is supported at its outer end by an outer leg assembly generally indicated by reference numeral 13. Similarly, stage surface member 10 has a corresponding outer leg assembly 12, which is shown in its extended position as explained hereinafter. At their ends, which are adjacent to each other, stage surface members 10 and 11 are supported by main support leg assemblies 14 and 15 respectively. These main support leg assemblies are interconnected by means of a brace 16, so that the main support leg assemblies 14 and 15 and brace 16 together form a base frame. Member 10 is pivotally connected to the base frame by means of links 21 and 22, while member 11 is pivotally connected to the base by means of links 23 and 24. Only one side of the structure is shown in FIG. 1, but it will be appreciated that links 21-24 have corresponding parts on the other side of the structure which cooperate to hingeably mount the stage surface members to the base frame.

As shown in FIG. 2, stage member 11 has a plurality of support or reinforcing rails, including angle irons 31 and 32 along each side, angle iron 33 along one end, angle iron 34, which is placed slightly away from the other end, and angle iron 35 across the center. Together, these angle irons form a framework for supporting and reinforcing the actual stage surface member itself, and provide a means for attaching the legs and various components.

Also as shown in FIG. 2, outer leg assembly 13 has a pair of individual legs 13a and 13b, one on either side which are pivotally mounted to reinforcing member 33 by means of suitable pivotal mounts 41a and 41b. In the preferred embodiment, these pivots may be a pair of tabs welded to member 33, with a pivot bolt passing through the tabs and the upper end of the leg. At the lower end of legs 13a and 13b, there is a cross member 13c. A pair of cross brace wires 13d and 13e may be provided for additional rigidity.

A cross member 43 extends between main support legs 15a and 15b which are positioned on either side of the table. Sliding collars 44a and 44b fit coaxially around legs 15a and 15b and are attached to cross member 43. Caster wheels 45a and 45b are attached to cross member 43.

As better shown in FIG. 4, a pair of links 23 and 24 are pivotally connected to a bracket 25 which is attached to frame reinforcing member 34. The other ends of links 23 and 24 are pivotally connected to brace 16. A similar construction is used for connecting member 10 to brace 16 by means of links 21 and 22. Portions of the stage member reinforcing rail have been broken away from the member 11 to more clearly show the details of connection. Another pair of links 46 and 47 connect from the sliding collars on the main support legs to brackets which in turn are mounted to cross brace 34.

An outer leg control link 51a connects from main support leg 15a to outer leg 13a. As seen in FIG. 2, the equivalent control link 51b is found on the other side of the stage surface member. Also, as seen in FIG. 1, a corresponding control link 52, is provided for stage surface member 10. This link likewise has left and right portions but only one side is visible in FIG. 1.

The details of construction and operation of the elements thus far described are set forth in greater detail in U.S. Pat. No. 3,351,029 previously referred to. Briefly, the folding stage may be folded up by swinging the outer portions of both stage surface members 10 and 11 upward to where they meet in a vertical plane above the base frame. The upward pivoting movement is made possible by pivoting links 21-24, and at the same time links 46 and 47 cause the sliding collars 44 to slide downward bringing the wheels 45a and 45b into contact with the ground and lifting main support legs 14 and 15 slightly off the surface. Also during the folding motion, control links 51 and 52 fold outer leg assemblies 12 and 13 inward against the undersurface of stage surface members 10 and 11. The resulting folding position, as indicated in FIG. 2 and in the solid line portion of FIG. 5, represents a compact storage arrangement that permits the stage to be wheeled away to a storage area.

According to the present invention, elevational adjustment is accomplished primarily by means of auxiliary support legs. As seen in FIG. 2, a pair of leg structures 60a and 60b are provided on stage surface member 11. The following detailed description is given with respect to leg 60a, but it will be appreciated that the same description applies with respect to leg 60b.

In the preferred embodiment, auxiliary support leg 60a has a generally L-shaped tubular section 61. A bracket 62 is welded to one end of tubular member 61, and bracket 62 is pivotally connected to cross brace reinforcement member 35 by means of a pivot bolt 63. Another tubular section 64 is provided generally parallel to a portion of tubular member 61, and a brace 65 may be welded therebetween to hold them in position. A tab welded to one end of tubular member 64 is pivotally connected by means of a pivot bolt 66, to an angle bracket 67 which is bolted or welded or otherwise attached to cross brace angle bracket 34.

A U-shaped foot member 68 is made of a tubular member having a small enough diameter to fit inside the open ends of tubular members 61 and 64. This foot member 68 is held in place by pins 69 passing through holes provided therein. Additional holes may be provided in the straight portions of foot member 68, so that different adjustment heights are possible by pulling member 68 further out and reapplying the pins 69 in the other holes.

A tab 70 is welded to a portion of tubular member 64 in such a position as to fit between mating tabs 71 provided along the bottom of cross brace 43. Tabs 70 and 71 serve to positively locate and laterally stabilize the auxiliary legs when they are in their down position.

Means are provided for adjusting the length of the outer leg assemblies. As shown in FIG. 1, in the preferred embodiment outer leg 13a is tubular in configuration, and has a telescoping inner portion 17a. Similarly, portion 18a fits telescopically inside outer leg 12 of the other portion of the stage. The telescopic inner portions of the legs are held in position by means of pins or bolts 19, and a plurality of holes are provided in the telescopic inner portions so that different adjustment heights are possible. The lowest adjustment height position corresponds to the length of the main support legs 14 and 15, while additional adjustment height positions correspond to different adjustment heights of the foot portions 68 of the auxiliary support legs.

As shown in FIG. 1, stage surface member 10 has a pair of auxiliary support legs designated by reference numeral 80 (only one of which is visible in the side view of FIG. 1) and these correspond to auxiliary support legs 60a and 60b, previously described, of stage surface member 11.

For illustrative purposes, FIG. 1 is divided showing the left hand portion of the stage set in an elevated position, with the right-hand portion set in its lowest position. In its lowest position, the stage rests on main support legs 14 and 15 and the outer leg assemblies when set to their lowest height; and the auxiliary support legs are folded up. In its elevated position or positions, the stage rests upon auxiliary support legs 60 and 80, and the outer leg assemblies in their extended position or positions.

The operation of the invention in adjusting the stage from a low position to a higher position will now be described with primary reference to FIG. 5. In FIG. 5, the solid line portion indicates the stage folded up in its storage position, with stage surface members 10 and 11 adjacent each other in a vertical position over the base frame. After wheeling the stage to the desired location in the room, the auxiliary support legs 60 and 80 (two per side) are pivoted outward to a position wherein they are perpendicular to their respective stage surfaces. The adjustable U-shaped telescoping foot portion of each of the auxiliary support legs can at this time be adjusted to the desired height and the pins reinserted to hold them in that position. The two stage surface members 10 and 11 are then manually pivoted outward and downward, one at a time, to the intermediate position indicated by the dotted lines in FIG. 5. In this position, the foot portion of the auxiliary support legs just contacts the floor at points 88 and 89, thereby stopping the pivoting of the stage momentarily. In this position, the outer leg assemblies 12 and 13 can be adjusted by removing the pins 19 and pulling the telescoping inner portions out to a position corresponding to the height previously set on the auxiliary support legs. The pins are then reinserted in the outer leg assemblies.

To finish erecting the stage, the person opening the stage selects either side, and simply pushes downward on the end of the stage surface member. Either side can be used, but for purposes of explanation, assume that the operator selects to push downward on the left-hand side, on the end of stage surface member 10, as indicated by arrow 90 in FIG. 5. The force thus applied causes stage surface member 10 to pivot about the auxiliary support leg 80, and downward to the operational position indicated by the broken lines in FIG. 5. As the left end of stage member 10 is brought down into position, its right end, which is connected to the main support legs and the base frame, is lifted upward, lifting the main support legs off the floor. At the same time, stage surface member 11 is pivoted to its horizontal position and pulled to the left a distance indicated by arrow 91. It should be pointed out that the pivoting motion has the effect of lightening the half of the stage which is being slid into position, thereby minimizing any danger of marring the floor.

It is thus apparent that the main support legs, in addition to providing the extra height required for elevational adjustment, also served in a unique manner as a rocking point or pivot when erecting the stage to its higher position. For this purpose, in the preferred embodiment the foot portion 68 of the auxiliary support legs is configured with a curved portion. This curved portion facilitates the rocking or pivoting movement, making it easier and smoother for the operator to apply the downward force at 90 while at the same time minimizing any marking or scuffing of the floor. By the same token, the curved foot serves as a skid, allowing the auxiliary support leg on the other side to slide laterally across the floor a short distance into position as indicated by arrow 91, further minimizing any marking of the floor.

It will also be apparent that other shapes and configurations could be used for the auxiliary support legs, while still achieving the primary function of the present invention. For example, a caster wheel could be used at the foot of the auxiliary support leg to provide the pivoting or rocking motion, as well as a rolling motion when the other side is pulled into place. However, in stages intended for carrying very heavy loads while in use, the structure shown in the drawings would be preferred. Alternatively, a flat platform foot portion pivotally connected to the bottom of the auxiliary support legs could be used.

It should be further appreciated that the rocking or pivoting action described above for final setup of the stage to its elevated position is much convenient, and requires much less effort than would be the case if workmen were required to lift and hold the stage while another workman was required to telescopically adjust the legs. Further, the relatively great leverage provided from the end of the stage to the pivot point at the foot of the auxiliary support leg further eases the setup operation.

Resetting the stage to a folded or a lower position is accomplished by a reverse operation of the steps set forth above.

Thus it will be seen that the present invention provides an improved elevationally adjustable foldable stage, having a simplified construction and providing simplified and convenient one-man operation in setting up the stage to higher elevations.

While the embodiment shown in FIGS. 1-5 operates satisfactorily with a wide variety of normal loads, the possibility exists that an unusual loading situation might be encountered with heavy load concentrations over the center portion of the stage combined with light loads or no loads on the outer portions. If such a loading situation were to occur while the stage is being supported in its elevated position by the auxiliary support legs, there is a possibility that the two stage surface members would rock downwardly at the center of the stage and upwardly at their extremities. This type of rocking would only occur in the case of extremely poor load distribution with great concentrations over the center of the stage, and at any rate the rocking would not result in complete fold up of the stage since such action would be arrested when the main support legs came into contact with the floor. Nonetheless, in order to prevent this possibility, a modified auxiliary support leg structure can be used.

The preferred embodiment of this modified auxiliary support leg is shown in the stage of FIGS. 6 and 7. The same reference numbers which were used in the embodiment of FIGS. 1-5 are used for the same parts in FIGS. 6 and 7, and will not be described in detail. The main difference between the embodiment of FIGS. 6 and 7 and the embodiment of FIGS. 1-5 centers in the auxiliary support legs, of which leg pair 80 is indicated in FIG. 7 in conjunction with stage surface member 10, and leg 60a is indicated in conjunction with stage surface member 11.

Leg 60a includes a first upright portion 161 and a second upright portion 162. A cross brace 165 may be welded between the upright portion for added rigidity. A floor or surface contact portion 163 connects from upright portion 161. A curved portion 164 connects between the second upright portion 162 and the floor contacting portion 163. In the preferred embodiment, the entire auxiliary support leg is made of a tubular member with appropriate bends to achieve the desired shape. The remaining auxiliary support leg on stage surface member 11, and the pair of auxiliary support legs on stage surface member 10 are generally similar to leg 60a.

As seen in FIG. 6, the pivotal attachment of the legs to the stage surface members is generally the same as in the embodiment of FIGS. 1-5. With specific reference to auxiliary support leg 60a, upright 162 pivotally connects to bracket 67 by means of pivot bolt 66. Upright portion 161 is connected by means of a pivot bolt 63a to the flange portion of cross brace reinforcement member 35a. In the embodiment of FIG. 6, the auxiliary support legs do not have the L-shaped extension portion 61 as shown in FIG. 2, and reinforcement member 35 of FIG. 2 has been relocated closer to the auxiliary support legs as indicated at 35a of FIG. 6. However, it will be understood that reinforcement member 35 can be placed at any position and L-shaped extension 61 can be included or deleted, as desired, without departing from the scope of the present invention.

The auxiliary support legs may be secured in their folded position as shown in FIG. 6 by a pair of rubber or elastic straps 170a and 170b. The straps preferably have hooks in their ends which fit into holes provided in the frame reinforcing members 34 and 35a so that the strap can be put in place as indicated by strap 170b to hold the auxiliary support legs in their storage position.

Referring again to FIG. 7, it will be appreciated that the floor or surface contacting portion 163 of the auxiliary support leg extends towards the center of the stage, beneath the hingeable connection of the two stage surface members to the base frame. Specifically, floor contacting portion 163 has a floor contacting surface which extends not only directly beneath the auxiliary support legs, which was the case with the embodiment of FIGS. 1-5, but which also extends in the direction towards the center of the stage. Thus, a portion of floor contacting portion 163 extends inwardly towards the center of the stage with respect to the extended centerline of upright section 162, and approximately even with the extended centerline of the main support leg 15a. The same situation exists with respect to the inwardly extension of auxiliary support leg 80 on the other side of the stage. This gives the stage of FIGS. 6 and 7 more support under the center of the stage so as to resist unwanted pivoting or rocking moments which may be applied thereto by poorly distributed concentrated loads over the center of the stage.

It will be appreciated that the inwardly extending floor contact portion of auxiliary support legs can be extended inwardly by whatever distance is desired; however, it has been found that legs configured essentially as shown in FIGS. 6 and 7 provide adequate support for all practical purposes. It will further be appreciated that instead of making the modified shaped auxiliary leg from a single member with appropriate bends, the inwardly extending floor contacting portion could be a separate loop, bar, stub, or the like welded or otherwise connected at the foot portion of the auxiliary support leg. It will further be appreciated that the auxiliary support leg of FIGS. 6 and 7 can be made with separate upper and lower tubular portions that telescope together and are secured by means of adjustment pins, in a manner analogous to the embodiment of FIGS. 1-5 so as to provide for degrees of elevational adjustment.

In the embodiment shown in FIGS. 6 and 7, curved portions 164 serve as the rocking or pivoting zone for ease in setup of the stage, in the same manner as previously described with respect to FIG. 5.