US3663078A

US3663078A - Receptacle and improved floating platform therefor

Info

Publication number: US3663078A
Application number: US81920A
Authority: US
Inventors: William C Moore; Alfred J Boos
Original assignee: INSULATING FABRICATORS Inc
Current assignee: INSULATING FABRICATORS Inc
Priority date: 1970-10-19
Filing date: 1970-10-19
Publication date: 1972-05-16
Anticipated expiration: 1989-05-16

Abstract

A doff truck having an improved floating platform is disclosed herein. The floating platform positioned within the doff truck or other type work receptacle is spring loaded to maintain the working surface of the platform at a convenient level for an operator who is utilizing the contents from the truck or receptacle. The platform is supported by a scissors type collapsible structure having spring means associated therewith. The platform, per se, is pivotally connected at one end to the supporting structure whereby, the spring means acting on the platform and the structure biases the platform around its pivotal connection to an inclined position. The inclined surface of the floating platform permits articles thereon to roll down the incline and collect at one end of the receptacle, whereby an operator may work from the one end only. Various pivotal connections and spring arrangements for providing the inclined floating platform are disclosed. Once the platform receives a sufficient amount of weight produced by articles placed thereon, the weight of the articles overcomes the bias of the spring means and the platform assumes a horizontal attitude. After the addition of further articles onto the platform, the platform, while maintaining the horizontal attitude, moves downwardly within the receptacle as the added weight gradually overcomes the force of the spring means.

Description

United States Patent Moore et al.

[ 51 May 16, 1972 RECEPTACLE AND IMPROVED FLOATING PLATFORM THEREFOR William C. Moore; Alfred J. Boos, both of Spartanburg, SC.

Inventors:

[73] Assignee: Insulating Fabricators, lnc., Spartanburg,

Filed:

Appl. N0.:

Oct. 19, 1970 [56] References Cited UNITED STATES PATENTS 3/1963 Berridgeetal. 108/136 5/1963 Fisher ..312/7l Primary Examiner-James C. Mitchell Attorney-Wellington M. Manning, Jr.

[ ABSTRACT A dofi truck having an improved floating platform is disclosed herein. The floating platform positioned within the doff truck or other type work receptacle is spring loaded to maintain the working surface of the platform at a convenient level for an operator who is utilizing the contents from the truck or receptacle. The platform is supported by a scissors type collapsible structure having spring means associated therewith. The platform, per se, is pivotally connected at one end to the supporting structure whereby, the spring means acting on the platform and the structure biases the platform around its pivotal connection to an inclined position. The inclined surface of the floating platform permits articles thereon to roll down the incline and collect at one end of the receptacle, whereby an operator may work from the one end only. Various pivotal connections and spring arrangements for providing the inclined floating platform are disclosed. Once the platform receives a sufi'icient amount of weight produced by articles placed thereon, the weight of the articles overcomes the bias of the spring means and the platform assumes a horizontal attitude. After the addition of further articles onto the platform, the platform, while maintaining the horizontal attitude, moves downwardly within the receptacle as the added weight gradually overcomes the force of the spring means.

17 Claims, 8 Drawing Figures PATENTEBMM 16 I972 SHEET 1 BF 2 FIG .2

PATENTEDHAY 16 I972 3. 663 078 sum 2 BF 2 INVENTORS WILLIAM C. MOORE BY ALFRED J.BOOS

FIG 8 A flwijzuvopgr RECEPTACLE AND IMPROVED FLOATING PLATFORM THEREFOR BACKGROUND OF THE INVENTION Various receptacles that are employed to hold and transport work articles are used throughout industry. In the textile industry in particular, doff trucks and the like are used to transport bobbins and the like to and from the processes in which the bobbins are utilized. These trucks are of such physical dimensions that operators removing the bobbins or other articles therefrom would have to bend over to reach down into the receptacle if a true bottom were used for supporting the articles. As a result of this inconvenience and also as a means to improve efiiciency in the textile processes, false floating bottoms have been employed to constantly maintain the top layer of articles near the top of the container. In so doing, the operator may remove or deposit the articles without bending which both lightens the task and also speeds up the unloading or transfer process.

Floating platforms or false bottoms employed in receptacles such as doff trucks, have been designed so as to assume various shapes and to function in various ways. With the floating platforms, however, several problems have existed leading to deficiencies of these existing platforms. For example, if the platform is permanently retained in a horizontal plane and moves up and down in the receptacle while remaining horizontal, the operator continues to experience problems. The receptacles are generally of such a size that the operator, to remove all the articles therefrom, must either reach over the receptacle or walk around same which again adds to inefficiency in the textile process and also is both burdensome and a possible safety hazard for the employee.

Additionally, certain platforms are permanently maintained on an incline and supported by a spring means. Addition of weight to the permanently inclined platform causes the platform to move into the receptacle while constantly retaining the inclined attitude. The permanently inclined floating platform thus permits the articles in the receptacle to be collected at one end, whereby the operator can stand at the one end and remove all the articles. Such an embodiment, however, does not add to the overall efficiency of the process, in that, less articles can be placed in the doll truck with a permanently inclined floating platform than witha horizontal floating plat form.

The two types of floating platforms described above are both true advances over a work receptacle having a true bottom. Both, however, do possess the deficiencies mentioned above that detract from the advantage of using same.

The present invention overcomes the problems of the prior art and provides an improved structure without any of the disadvantages mentioned above. Deficiency of the permanent horizontal floating platform is obviated, in that, the floating platform of the present invention permits the articles thereon to collect at one end of the receptacle in which they are placed. At the same time, the present floating platform avoids the deficiencies of the permanently inclined floating platform due to the fact that the inclined platform of the present invention will, under a predetermined weight, flatten to a horizontal position, thereby permitting more articles to be placed in the receptacle.

The prior art contains teachings pertinent to the present invention, but does not alone or in any combination teach or suggest the improved doff truck or the improved floating platform of the present invention. Exemplary of the prior art are U. S. Pat. Nos. 3,080,066 to Bar-ridge et al.; 2,980,287 to Fisher; 2,980,481 to Fisher; 3,418,031 to Fisher; 2,806,607 to Korngold; and 2,850,203 to Eurey.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved floating platform system for use within a work receptacle.

Another object of the present invention is to provide a dofi" truck having an improved inclined floating platform according to the teachings of the present invention.

Still further, another object of the present invention is to provide an improved work receptacle that is capable of continually providing articles in said receptacle at one end thereof, and that is also capable of receiving a maximum number of articles for the type receptacle being described.

Generally speaking, the present invention relates to a floating platform system for a receptacle comprising a first support frame; a second support frame positioned above said first support frame and being operatively associated therewith for up and down movement with respect thereto, a planar surface positioned atop said second support and pivotally secured thereto, and spring means normally biasing the end of said planar surface opposite said pivot away from said second support frame, said spring means further providing resilient support to said second support frame and said planar surface.

More specifically, the present invention is directed to a receptacle such as a doff truck that has sides, an open top and either a bottom or framework at the bottom to receive a floating platform system such as was described above. A preferred floating platform system more specifically is comprised of a pair of scissors supports that are pivotally secured to support frames so as to move up and down with respect thereto whereby the upper support frame moves accordingly. A planar surface or platfonn is pivotally secured at one end to the upper support frame while the other end is free at least for limited movement. Spring means positioned on the bottom support frame provide continuous bias against the upper sup port frame and the planar surface, whereby the planar surface is normally biased to move around its pivotal connection to an inclined attitude.

A doff truck such as described in the preceeding paragraph having a floating platform system according to the present invention may receive work articles such as bobbins or the like which will initially roll down the inclined planar surface and collect at the lower end of the planar surface in the top portion of the doff truck. As more bobbins or the like are placed on the planar surface, the weight of the bobbins overcomes the force of the spring means and the inclined planar surface pivots downwardly toward a horizontal position where the planar surface rests on the upper support frame. Once the planar surface reaches a horizontal attitude and additional bobbins or the like are placed thereon, the planar surface will move downwardly into the receptacle while retaining the horizontal attitude. This procedure continues with the addition of additional bobbins until the planar surface has been forced downwardly into the doff truck to its lowest possible position. Subsequently, as the bobbins are removed from the dofi truck, the bias of the spring means under the upper support frame and planar surface causes the planar surface to move upwardly through the doff truck. At the upward limit of movement for the upper support frame, the continued removal of bobbins from the planar surface permits the spring means to bias against the planar surface to again cause the planar surface to move around its pivotal connection with upper support frame toward the unloaded, inclined position. In so doing, any bobbins remaining on the platform will move down the incline when space is available and collect there until removed by the operator.

The planar surface according to the present invention may assume an inclined attitude from end to end of a doff truck or receptacle or from side to side of a dofi truck or receptacle depending upon the location of the pivotal connection between the planar surface and the upper support frame. Moreover, since various sizes of springs may be utilized according to the dictates of the articles to be placed in the receptacle, it may be desirable to provide movement limit means for the planar surface so as to control both the degree of incline of the planar surface at its uppermost position and also so as to control the distance that the planar surface may move upwardly away from the upper support frame.

The spring means utilized to provide continuous bias against the upper support frame and the planar surface of the floating platform system of the present invention may be of various types. In this regard, one spring means would include the use of two coil springs, one of which is secured to a lower support frame with the other end secured to the upper support frame. The second coil spring which may be a larger spring than the first, would be secured at one end to the lower support frame and at an opposite end to the underside of the planar surface. A second spring system might employ the use of three coil springs whereas two of the coil springs are secured at one end to the lower support frame and at an opposite end to the upper support frame while the third spring is positioned therebetween with one end secured to the lower support frame and the opposite end secured to the underside of the planar surface. Still further, another spring system according to the teachings of the present invention would employ the use also of three coil springs where two coil springs are placed as described above and the third coil spring is a much smaller and shorter coil spring and would be secured at one end on top of the upper support frame and at an opposite end on the underside of the planar surface. In the sense of the spring means utilized according to the teachings of the present invention, any suitable spring means may be utilized that will maintain the inclined planar surface so as to collect work articles at one end of the receptacle until sufi'icient weight is placed thereon to force the incline into horizontal attitude. At the same time, the design of the particular spring means should be such that the floating platform system will collapse to a maximum extent in the bottom of the receptacle so as to permit a maximum number of articles to be placed in the receptacle at one time.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of a dofi truck having a floating platform system deployed therein according to the teachings of the present invention.

FIG. 2 is a side cross sectional view of a doff truck taken along lines 11-11 of FIG. 1 and showing the planar surface at an inclined attitude in the top of the receptacle whereby work articles therein will collect at the lower end of the incline.

FIG. 3 is a cross sectional view of a doff truck showing the planar surface with sufficient weight thereon to be forced into a horizontal attitude.

FIG. 4 is a cross sectional view of a receptacle showing a floating platform system according to the teachings of the present invention wherein the floating platform has been depressed by the weight of articles thereon to a partially collapsed position.

FIG. 5 is a cross sectional view taken along lines V-V of FIG. 1 butshowing a further embodiment of the present invention.

FIG. 6 is a side elevational view of a floating platform system according to the teachings of the present invention showing a particular embodiment of spring means.

FIG. 7 is a side elevational view of a floating platform system according to the teachings of the present invention showing a further embodiment of spring means.

FIG. 8 is a side elevational view of a floating platform system according to the teachings of the present invention showing still a further embodiment of spring means.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS Specific and preferred embodiments of the present invention will now be described with reference to the figures. FIG. 1

shows a dofi truck having side walls 10 and end walls 12 one-half inch vertical difference is generally utilized. The doff truck further is shown having a rub rail 19 extending completely therearound in the lower half of the receptacle body. Rub rail 19 is positioned at a height equal to protective rails that are provided on textile equipment. Hence, the doff truck passing near the textile equipment will engage the rail of same at the rub rail 19 on the truck, whereby damage is avoided to either the textile equipment or the truck. As can further be seen in FIG. 1, the doff truck has an inclined planar surface 20 residing therein and having a plurality of bobbins B resting thereon at the lower end of the incline.

The doff truck may be provided with a bottom wall or may I simply have sufficient structural members across the bottom to support the floating platform that is placed therein.

FIG. 2 is a vertical cross sectional view of a doff truck as taken along lines 11-11 of F IG. 1. Hence, a doff truck having a side wall 10 and end walls 12, bottom framework 15 and wheels l4, l6 and 18 has a floating platform positioned therein for receiving articles such as bobbins B. .The floating platform comprises a lower support frame 30 which, as may be seen in FIGS. 2 and 5 comprises parallel

longitudinal struts

31 and 32 that are united by crossing supports 33. At the top of the floating platform system is an upper support frame 40 which like lower support frame 30 is comprised of parallel longitudinal struts 41 and 42 which are united by crossing supports 43. Corresponding longitudinal struts for the upper and lower support frames, 31 and 32 respectively are connected by a collapsible scissors support 50. Scissors support 50 comprises a first diagonal leg 52 and a second diagonal leg 54. As shown in FIG. 2, the lower end of leg 52 is pivotally secured to strut 32 at 55 whereas the upper end of leg 52 has a pin'52' which is slidably received in a slot 44 that extends along longitudinal strut 42 of upper support frame 40. Second leg 54 of scissors support 50 has a pin 54' in its lower end which is slidably received in a slot 34 which extends axially along one end of longitudinal strut 32 of lower support frame 30. The opposite, upper end of leg 54 is pivotally secured at 56 to the end of longitudinal strut 42 opposite the axial slot 44. Additionally,

legs

52 and 54 of scissors support 50 cross at 57 where they are pivotally secured to each other.

The platform on which the bobbins or the like are placed is a planar surface '20 having a depending skirt 2 1 therearound which is pivotally secured at 22 to one end of the upper sup port frame 40. The opposite end of planar surface 20 is either free from upper support frame 40 or is provided with a movement limit means 24 which is illustrated in FIG. 2 as a link chain. As can better be seen in FIG. 3, link chain 24 is secured at one end to the underside of planar surface 20 and is provided at the opposite end with a stop 25 which engages a part of the upper support frame 40 during upward movement of planar surface 20 so as to limit the upper movement thereof. Chain or limit means 24 may also serve another purpose. Occasionally bobbins B are stacked on inclined planar surface 20 in such a manner that they will not slide or roll to the bottom of the incline. Such a jam can be broken by pushing down on the platform 20 followed by quick release thereof which produces a jolt when stop 25 of chain 24 strikes the upper support frame. Work articles such as bobbins B move to the lower end of the incline in much better fashion, however, when the planar surface 20 is covered with a friction reducing substance. Example of such substances include polyethylene, Teflon, a polytetrafluoroethylene manufactured by E. I. du- Pont Nemours and Company, acrylics, vinyls and the like. Kydex, an acrylic-polyvinyl chloride alloy manufactured by Rohm & Haas Company has been found to work very effectively when coated onto planar surface 20.

Spring means are secured at a lower end to the lower support frame 30 and at an upper end to the upper support frame 40 and/or the underside of planar surface 20. In FIG. 2, spring means are exemplified by two

coil springs

62 and 64. Coil spring 62 is secured at its bottom end to lower support frame 30 and at its opposite upper end to upper support frame 40. Coil spring 64, on the other hand, is secured at its lower end to lower support frame 30 and at its upper opposite end to the underside of planar surface 20. While coil springs are illustrated as spring means in FIG. 2 and are preferred according to the teachings of the present invention, obviously other types of spring means may be employed to provide resilience to the floating platform system In this regard, however, the spring means employed to provide an optimum system, should be collapsible into the space between the underside of planar surface 20 and the lower support frame 30 whereby a maximum collapse of the floating platform is available so as to permit the doff truck or the like to receive a maximum number of work articles.

FIGS. 2, 3 and 4 show similar cross sections of a doff truck having a floating platform system according to the teachings of the present invention therein. As such, the structural members of FIGS. 3 and 4 are like those of FIG. 2 and will not be discussed further at this point. In FIG. 2, the floating platform is shown with the planar surface 20 in an inclined position so as to permit work articles such as bobbins to move by gravity and collect at the lower end of the incline. FIG. 3 shows planar surface 20 with a sufiicient number of bobbins B placed thereon to overcome the bias of spring 64 whereby planar surface 20 moves downwardly while pivoting around pivot point 22 to assume a horizontal attitude. FIG. 4 shows a further number of bobbins B placed within the doff truck whereby the composite weight of the bobbins overcomes the force of both

springs

62 and 64 so as to force the floating platform toward the bottom of the truck while continuing to present bobbins B at the top of the doff truck for ease of removal or for placement of further bobbins thereon. FIG. 4 shows the planar surface 20 intermediate the depth of the doff truck body. Accordingly, should sufficient additional bobbins B be placed therein, planar surface 20 will move further down into the doff truck body to its maximum collapsed position.

The collapse of the floating platform is brought about in the following manner. Referring to FIG. 2, it is noted that the scissors support 50 is provided with

pivotal connections

55, 56 and 57 and sliding pivotal connections at pins 52' and 54' which are respectively received in

axial slots

44 and 34. Hence, as weight is placed on planar surface 20 sufficient to begin to overcome the bias of the spring means, first leg 52 pivots around its pivotal connection with lower support frame 30 while second leg 54 pivots around its pivotal connection 44 at upper support frame 40. Simultaneously therewith, pins 52 at the end of first leg 52,and 54' at the end of second leg 54 slide along

axial slots

44 and 34 respectively, whereby upper support frame 40 moves downwardly against the bias of

springs

62 and 64 towards lower support frame 30.

FIG. 5 shows a further embodiment of the present invention. A doff truck like the one shown in FIG. 1 has a floating platform system positioned therein. The platform system as shown in FIG. 5 is different from the platform shown in FIG. 2 in two respects. The planar surface 20' as shown in FIG. 5 is pivotally connected along one of the scissors supports 50 at 22' as opposed to the platform shown in FIG. 2 which is pivotally connected across the upper support frame 30. Hence, instead of providing an incline from one end of a side wall to the opposite end of a side wall 10, the embodiment as shown in FIG. 5 provides an inclined planar surface from one side of an end wall 12 to the opposite side of an end wall 12. Moreover, inclined planar surface 20' is shown without a movement limiting means 24 as was described with respect to FIG. 2. In this regard, the movement of planar surface 20' in an upward direction around the pivot point 22', is limited by the maximum length of the coil spring 64' or by the spring means in general if other spring arrangements are employed.

The spring means utilized according to the teachings of the present invention may assume various configurations and include different types of springs. Several possible variations of the spring means are shown in FIGS. 6, 7 and 8. In FIGS. 6, 7 and 8, the basic structure of the floating platform system, per se, is the same as was described with regards to FIG. 2, and accordingly will not be further elaborated on at this point. In FIG. 6, however, the spring means includes a first coil spring 162 that is secured to the lower support frame while the upper end of coil spring 162 is secured to the underside of planar surface 120. Positioned apart therefrom is a second coil spring 164 which is secured at its lower end to lower support frame 130 while the opposite end thereof is likewise secured to the underside of planar surface 120.

FIG. 7 shows a pair of coil springs 262 and 264 that are secured at their lower ends to lower support frame 230 and at their upper ends to upper support frame 240. Additionally, a third coil spring 266 is positioned between coil springs 262 and 264 and is secured at its lower end to lower support frame 230 and at its upper opposite end to the underside of planar surface 220.

FIG. 8 shows a further spring embodiment wherein a pair of coil springs 362 and 364 are secured at their lower ends to lower support frame 330 and at their upper opposite ends to upper support frame 340. A third smaller coil spring 368 is positioned approximately above coil spring 364 and is secured at its lower end to upper support frame 340 and at its upper end to the underside of planar surface 320.

The floating platform system of the present invention has been described with respect to a scissors type collapsible support for the platform wherein spring bias means provide resilience to the platform and position the platform in the receptacle in accordance with the weight distribution across the platform. It is not intended, however, that the present invention be limited to a scissors type arrangement as is particularly shown in the drawings and described herein. Instead, other types of collapsible platforms having a planar surface pivotally secured at one end to the upper surface thereof so as to properly distribute work articles within a receptacle is anticipated by the present invention. In further regard to the spring means of the present invention, while coil springs have been described in particular as being suitable, obviously other types of springs may be used so long as the platform collapses in the manner as hereinbefore described. Moreover, depending upon the particular work load, the various springs of the embodiments shown herein or otherwise used, can be of a par ticular sizeso as to be suitable for the anticipated work load. In other words, referring to FIG. 2, it might be desirable to use a thirty pound spring for, coil spring 62 and a forty pound spring for coil spring 64, or such other springs as might be required to properly handle the anticipated work load. The term support frame as used herein is not intended to dictate a separate portion of the platform system. Certainly a lower and upper support frame could be manufactured and then connected to opposite ends of a collapsible support. Likewise, however, the support, per se, could be provided with ample structural members at opposite ends thereof; the support could utilize part of the receptacle as a support frame, or the like.

The present invention has been described with reference to a doff truck which, of course, is used in the textile industry. Obviously, a platform system such as is described herein could advantageously by employed in any receptacle in which it is desirable for the work articles placed therein to always be available at the top and collected at one end or one side of the receptacle to facilitate ease of removal and speed of removal.

' Having described the present invention in detail, it is obvi ous that one skilled in the art will be able to make modifications and variations thereto without departing from the scope of the invention. Accordingly, the scope of the present invention should be determined by the claims appended hereto.

What is claimed is:

l. A floating platform system for a receptacle, comprising:

a. a first support frame;

b. a second support frame positioned above said first support frame and being operatively associated therewith for up and down movement with respect thereto;

0. a planar surface positioned atop said second support and pivotally secured to said second support; and

d. spring means normally biasing the end of said planar surface opposite said pivot away from said second support frame, said spring means further providing resilient support to said second support frame and said planar surface.

2. A floating platform system for a receptacle as defined in claim 1 wherein said first support frame is connected to said second support frame by collapsible crossing members.

3. A floating platform system for a receptacle as defined in claim 2 wherein said first and second support frames have slots axially thereaiong to slidably receive appropriate ends of said collapsible crossing members.

4. A floating platform system for a receptacle as defined in claim 1 wherein a pair of scissors supports are connected to said first and second support frames, said scissors supports being adapted for pivotal collapsing upon being subjected to sufficient weight to overcome the bias of the spring means.

5. A floating platform system for a receptacle as defined in claim 4 wherein each scissors support comprises a first diagonal member pivotally secured at one end to one of said support frames and slidably and pivotally secured at an opposite end to said other support frame and a second diagonal member pivotally secured at one end to one of said support frames and slidably and pivotally secured at an opposite end to said other support frame, said diagonals crossing each other and being pivotally secured to each other thereat.

6. A floating platform system for a receptacle as defined in claim 1 wherein said planar surface has movement limit means associated with the end thereof opposite said pivotal connection to said second support frame.

7. A floating platform system for a receptacle as defined in claim 6 wherein said limit means comprises a member depending from the underside of said planar surface and associated with said second support frame at the downward end thereof.

8. A floating platform system for a receptacle as defined in claim 1 wherein said spring means comprise a first coil spring secured at one end to said first support frame and at an opposite end to said second support frame adjacent said pivot connection with said planar surface and a second coil spring secured at one end to said first support frame and at an opposite end to said planar surface, whereby said second coil spring normally biases said planar surface upward around its pivot connection with said second support frame to present an inclined platform.

9. A floating platform system for a receptacle as defined in claim 1 wherein said spring means comprise first and second coil springs secured between said first and second support frames and a third coil spring positioned between said first and second coil springs and secured between said first support frame and said planar surface, whereby said third spring normally biases said planar surface upwards around its pivot connection with said second support frame to present an inclined platform.

10. A floating platform system for a receptacle as defined in claim 1 wherein said spring means comprise first and second coil springs secured between said first and second support frames and a third spring secured between said second support frame and said planar surface, whereby said third spring normally biases said planar surface upward around its pivot connection with said second support frame to present an inclined floating platform.

1 1. A doff truck comprising:

a. side and end walls secured together to form a receptacle;

b. wheels rotatably secured to the underside of said receptacle; and

c. a floating platform residing within said receptacle, said floating platform comprising a first support frame, a second support frame positioned above said first support frame and being operatively associated therewith for up and down movement with respect thereto, a planar surface positioned atop said second support and pivotally secured to said second support, and spring means normally biasing the end of said planar surface opposite said pivot away from saidsecondsupport frame, said sprin means further providing resilient support to said secon support frame and said planar surface.

12. A doff truck as defined in claim 11 wherein said floating platform is secured to a framework across the bottom of said receptacle.

13. A doff truck as defined in claim 11 wherein said spring means is a plurality of coil springs.

14. A doff truck as defined in claim 11 wherein said planar surface has movement limit means associated therewith.

15. A doff truck as defined in claim 11 wherein said spring means comprise a first coil spring secured at one end to said first support frame and at an opposite end to said second support frame adjacent said pivot connection with said planar surface and a second coil spring secured at one end to said first support frame and at an opposite end to said planar surface, whereby said second coil spring normally biases said planar surface upward around its pivot connection with said second support frame to present an inclined platform.

16. A floating platform system as defined in claim 1 wherein the planar surface is covered with a friction reducing substance.

17. A dofi' truck as defined in claim 11 wherein the planar surface of the floating platform is covered with a friction reducing substance.

Claims

1. A floating platform system for a receptacle, comprising: a. a first support frame; b. a second support frame positioned above said first support frame and being operatively associated therewith for up and down movement with respect thereto; c. a planar surface positioned atop said second support and pivotally secured to said second support; and d. spring means normally biasing the end of said planar surface opposite said pivot away from said second support frame, said spring means further providing resilient support to said second support frame and said planar surface.

3. A floating platform system for a receptacle as defined in claim 2 wherein said first and second support frames have slots axially therealong to slidably receive appropriate ends of said collapsible crossing members.

11. A doff truck comprising: a. side and end walls secured together to form a receptacle; b. wheels rotatably secured to the underside of said receptacle; and c. a floating platform residing within said receptacle, said floating platform comprising a first support frame, a second support frame positioned above said first support frame and being operatively associated therewith for up and down movement with respect thereto, a planar surface positioned atop said second support and pivotally secured to said second support, and spring means normally biasing the end of said planar surface opposite said pivot away from said second support frame, said spring means further providing resilient support to said second support frame and said planar surface.

17. A doff truck as defined in claim 11 wherein the planar surface of the floating platform is covered with a friction reducing substance.