Material handling apparatus with shelf extension panel

Abstract

A material handling cart of the foldable type having a rear wall supported on a pair of casters, a pair of foldable side walls each supported on one individual caster, and middle and lower shelves each hinged to the rear wall so that each can be folded up against the rear wall before the side walls are folded around them. The particular improvement disclosed herein is a shelf extension panel associated with each of the shelves. Each extension panel is slidable underneath its associated shelf into a fully stored position, or it may be pulled partially forward to act as a shelf extension, or when pulled to a fully forward position it may be pivoted upward to provide a front wall enclosing the space above the shelf.

Description

BACKGROUND OF THE INVENTION

Material handling apparatus must meet many and diverse requirements which vary in numerous details depending upon the particular application. Some of the important factors involved are manufacturing cost, the ease and convenience of transporting and storing the apparatus when it is not in use, and the effectiveness of the apparatus when it is being used for its intended purpose.

The prior art is replete with numerous examples of storage shelf structures, and is also replete with numerous examples of wheeled vehicles such as carts and the like which are used for material handling purposes. The preferred embodiment of the present invention relates to a wheeled cart which incorporates a shelf structure.

One principal object of the invention is to provide an improvement in the collapsible or foldable type of material handling cart.

Another separate and distinct object of the invention is to provide an improvement in a shelf structure, which improvement will be of value irrespective of whether or not the shelf structure is associated with a wheeled vehicled.

SUMMARY OF THE INVENTION

According to the present invention an improved shelf structure is provided by incorporating guideway means beneath the respective ends of a normally horizontally disposed rectangular shelf. A movable panel is also provided which is adapted to be supported from the guideway means, beneath the shelf. In one position the panel may be entirely stored underneath the shelf; in another position it may be moved partially forward so as to provide a horizontal shelf extension; in yet another position the panel is moved to an extreme forward position and is pivoted upward so as to enclose the space about the shelf.

According to the present invention a collapsible or foldable material handling cart is provided which has two vertically spaced shelves, and a movable panel associated with each of the shelves. The movable panel may be stored beneath its respective shelf, may be moved to a partially forward position in which it acts as a shelf extension, or may be moved to an entirely forward position and pivoted upward so as to enclose the space above the shelf.

DRAWING SUMMARY

FIG. 1 is a perspective view of a material handling cart in accordance with the present invention;

FIG. 2 is a cross-sectional view of the lower shelf, with movable panel in stored position, taken on the line 2--2 of FIG. 1;

FIG. 3 is a cross-sectional view of the center shelf with movable panel in partially extended position, taken on the line 3--3 of FIG. 1;

FIG. 4 is a cross-sectional view taken on the line 4--4 of FIG. 2;

FIG. 5 is an exploded perspective view of one of the shelf and panel assemblies;

FIG. 6 is a perspective view of the material handling cart showing different positions of the shelves and movable panels;

FIG. 7 is a cross-sectional view taken on the line 7--7 of FIG. 6;

FIG. 8 is an elevational view taken on the line 8--8 of FIG. 6;

FIG. 9 is a fragmentary elevational view taken on the line 9--9 of FIG. 8;

FIG. 10 is a fragmentary cross-sectional view taken on the line 10--10 of FIG. 8;

FIG. 11 is a fragmentary cross-sectional view taken on the line 11--11 of FIG. 6;

FIG. 12 is an elevational view taken on the line 12--12 of FIG. 11;

FIG. 13 is a perspective view of the material handling cart showing still a third position of the shelves and movable panels; and

FIG. 14 is a cross-sectional view taken on the line 14--14 of FIG. 13.

PREFERRED EMBODIMENT

Reference is now made to the drawings, FIGS. 1 to 14, inclusive, illustrating the presently preferred form of the invention.

The novelty of the present invention resides in a movable panel associated with a shelf, which could be used in other material storage or material handling applications but is presently illustrated in conjunction with a collapsible material handling cart. The general arrangement of the collapsible cart is well-known in the art and will be described briefly and in rather general terms, since a more specific description would serve no useful purpose.

Thus the collapsible cart 10 includes a rear wall 12 and a pair of foldable side walls 20, 30. The rear wall 12 has bent-over edges 13, 14 which give the rear wall a shallow U-shaped configuration. Side wall 20 is attached to the edge 13 by means of a vertically spaced set of hinges 15, and in similar fashion the side wall 30 is attached to the rear wall edge 14 by means of a vertically spaced set of hinges 16.

A pair of casters 17, 18 are mounted by means of respective swivels from corresponding lower corners of the rear wall 12. Casters 21, 31 are attached to the lowermost outer edges of the side walls 20 and 30, respectively. When the side walls are expanded to their operative position, as shown in FIGS. 1, 6, and 13, the side walls together with the rear wall form a frame structure comprised of a plurality of vertical tubes and which has a U-shaped cross-sectional configuration in the horizontal plane. As is well-known in the art, the side walls 20, 30 may be folded in toward the rear wall 12, and when this folding or collapsed position is achieved the casters 21, 31 will then occupy positions relatively close to the rear wall.

The folding cart 10 also includes a bottom shelf or deck 40, and a center shelf 60. Bottom shelf 40 is attached to the lowermost frame member of rear wall 12 by means of a pair of hinges 19, and may therefore occupy either an operative horizontal position as shown in the drawings or else may be folded vertically upward to a folding position in which it is latched against the rear wall 12. In similar fashion the center shelf 60 is attached to rear wall 12 by means of hinges 19a, thus permitting the shelf to be either horizontally disposed in operative position or folded to a vertical position for transportation or storage purposes. FIG. 1 shows the horizontal position of center shelf 60 while FIGS. 6 and 13 show its raised position.

The collapsible cart as thus far described is well-known in the art, and the subject matter of the present invention resides in specific improvements which are yet to be described.

The material handling cart 10 includes a pair of movable panels MP1 and MP2. Movable panel MP1 is associated with the deck or bottom shelf 40, while movable panel MP2 is associated with the center shelf 60. The movable panels are identical to each other in their construction, and hence the same reference numerals will be used throughout for identifying the corresponding parts of these panels.

In general, each of the movable panels includes a rectangular frame 70 having a pair of laterally projecting posts 71a, 71b on its rearward edge, and a pair of laterally projecting pins 72a, 72b on its forward edge. The structure and function of both the posts and the pins will now be described in some detail.

The frame 70 includes a plurality of laterally spaced tubular members or ribs 75 which extend in a direction perpendicular to the rear wall 12 of the cart 10. Tubular members 75 are of approximately square cross-sectional configuration. Another square tubular member 71 forms a cross-member which extends across the rearward ends of the members 75, being welded to the upper surfaces thereof, as best seen in FIG. 5. The length of tubular member 71 is greater than the lateral extent of the frame members 75, and hence the projecting ends of tubular member 71 provide the posts 71a, 71b as previously described.

The posts 71a and 71b have several different functions or purposes. One function or purpose is to provide vertical support for the rearward edge of the moving panel when it is in a fully stored position underneath its associated shelf (see FIG. 2). A second function is to provide a cantilever support for the movable frame when in its partially extended position (see FIG. 3). In this position the upward movement of tubular member 71 is precluded by frame members 41, 42 of the corresponding shelf (see FIG. 4). A third function of the posts 41a, 41b is to provide a pivotal support for the rearward edge of the moving panel, when in its fully forward position, so that the moving panel can be raised to a vertical position in which it encloses the space above its associated shelf. FIG. 6 illustrates the vertical position of moving panel MP1.

Across the front end of the tubular members 75 there is another tubular member 72, located in the same plane as the members 75 and which is welded to their respective ends. Pins 72a, 72b are attached to the respective outer ends of the tubular member 72 (See detail views as shown in FIGS. 9 and 12). The tubular member 72 is used as a convenient handle for sliding the movable frame back and forth between its fully stored position, its partially forward position in which it acts as a shelf extension, and its fully forward position in which it acts as a vertical forward wall. The function of the pins 72a, 72b is to cooperate with latches 22, 32 attached to the respective side walls 20, 30, for holding the movable panel in its vertical position. (See FIGS. 7, 11, and 12).

Each of the shelves 40, 60 is provided with appropriate guideway means for supporting the corresponding movable panel. Since these guideway structures are identical for both of the shelves, the same reference numerals will be used throughout for the parts.

Referring particularly to FIG. 4, a pair of outer guide members 43, 44 are of L-shaped cross-sectional configuration and have their upper edges secured to respective tubular members 41, 42 which form a part of the corresponding shelf structure and extend in a direction perpendicular to the rear wall 12 of the cart. The lower portions of the guide members 43, 44 are horizontally disposed and occupy the same horizontal plane being turned inwardly toward each other. The outermost ones of the tubular members or ribs 75 of the associated movable panel are slidingly rested upon the inner and upper surfaces of the lower portions of the guide members 43, 44.

Still with reference to FIG. 4, there are a pair of guideways 45, 46 which are also of L-shaped configuration. The upper longitudinal edges of these members are welded to the under surfaces of the shelf frame members 41, 42, respectively. The lower portions of the guideways 45, 46 occupy a common horizontal plane, and are turned inwardly towards each other so as to provide sliding support for the posts 71a, 71b of the movable panel.

The forward ends of the guideways 45, 46 are closed by end pieces 45a, 46a respectively. (See FIG. 5). These end pieces capture the posts 71a, 71b, respectively, so that the moving panel cannot be removed or detached from its associated shelf.

The guide members 43, 44 do not extend the full width of the associated shelf, but are attached beneath the forward edge portion thereof. (See FIGS. 3 and 5). The guideways 45, 46, on the other hand, do extend the full front to rear distance of the shelf. (See FIG. 3 where it is clearly shown that the closed end 45a of guideway 45 is located somewhat forwardly of the most forward edge of the shelf 60).

Each movable panel is also provided with stops for preventing it from being accidentally dislodged from its stored position. As best shown in FIGS. 3 and 4, a pair of stops 77 are welded to the undersurfaces of the outermost ones of the members 75, near the forward edge of the movable panel but yet some distance back from the front edge bar 72. The position of the stops 77 is also clearly shown in FIG. 7. When the moving panel is in its stored position the stops 77 are located rearwardly of the guide members 43, 44. The rearward end edges of the guides 43, 44, therefore act as coacting stops. (See FIG. 2).

Pulling the movable panel out to an extended position is, however, very simple. The leading edge bar 72 is simply raised a sufficient distance so that the stops 77 will clear the upper surfaces of the guides 43, 44, respectively. This can easily be done since the outer dimension of the tubular members 75 of the movable frame is somewhat less than the horizontal space between the inner edges of the guideways 45, 46 (See FIG. 4).

FIG. 13 illustrates a very unique way in which the apparatus of the present invention may be used. As shown in FIG. 13 the center shelf 60 is raised to a vertical position where it is folded back against the rear wall 12. Movable panel MP2, rather than simply being extended out or being rotated up relative to the shelf, is instead rotated downward relative to the shelf. Thus movable panel MP2 is able to occupy a horizontal position, with pins 72a, 72b being latched by the latches 22, 32, respectively. Movable panel MP2 therefore acts as a top shelf or lid for the cart 10, with the whole interior of the cart being open and accessible from the front. This configuration of the cart is particularly useful when transporting packages of exceptional vertical height.

Each shelf when occupying its horizontal position is supported by studs 25, 35, attached to the inner surfaces of the side walls 20, 30, respectively.

A unique latch mechanism is provided for latching each of the shelves in its vertical position. This is a self-operating, gravity operated latch. There are only two of these latches, one for each of the shelves, and both of these latches are attached to the end portion 14 of rear wall 12. Each of the gravity latches L includes an inclined plane 81, an L-shaped bolt 82, and a collar 83 for holding the bolt. Latch L is also shown in FIG. 8. The collar 83 is a square tubular member of relatively short length and is vertically disposed. It is attached as by welding to one vertical surface of the square tubular post 14a. Post 14a is a vertically extending post which constitutes the forward-most portion of the rear wall edge 14 (See FIG. 1).

The collar 83 is attached to the rearward side of post 14a, away from the side wall 30. The L-shaped bolt 82 has a vertical shank which extends upward through the collar 83, and also has a horizontal shank which extends horizontally from the lowermost extremity of the vertical shank. The exterior corner surface of the L-shaped bolt 82 is rounded. Sloping cam member 81 is welded to the same surface of post 14a, some distance below the collar 83. The cam 81 slopes so that its lowermost end is directed toward the interior of the cart, i.e., toward the opposite side edge 13 of rear wall 12.

The operation of the gravity latch is illustrated in FIG. 10. When shelf 60 is swung vertically upward to its folded position it engages the horizontal arm of the bolt 82, swinging it back to the dotted line position 82'. Shelf 60 is moved further back toward rear wall 12, to the dotted line position 60'. This permits the horizontal leg of bolt 82 to return to its solid line position as shown in FIG. 10. Shelf 60, when released by the hand of the operator, may then pivot outward where it is retained by the leg of bolt 82, as shown in solid lines in FIG. 10. In order to release the shelf it is necessary to push both the bolt 82 and the shelf 60 toward the rear wall 12, holding the bolt in the dotted line position as shown by 82' until the shelf is able to clear it upon returning towards its unfolded or horizontal position. The advantage of this gravity latch is that the mere act of raising the shelf to its vertical position causes the latch to operate, thus preventing an inadvertent dropping of the shelf back to its horizontal position.

The invention has been described in considerable detail in order to comply with the patent laws by providing a full public disclosure of at least one of its forms. However, such detailed description is not intended in any way to limit the broad features or principles of the invention, or the scope of patent monopoly to be granted.

Claims

What is claimed is:

1. In material handling apparatus including a rear wall, a pair of generally parallel side walls, and a shelf extending horizontally between said side walls, the improvement comprising:

horizontal guideway means carried beneath respective ends of said shelf and extending parallel to the respective side walls;

a pair of horizontal guide members supported from respective ones of said side walls at the front edges thereof and being disposed inwardly from and beneath the respective guideway means;

a panel adapted to be horizontally stored beneath said shelf, said panel having a plurality of parallel ribs disposed parallel to said side walls, the two outermost ones of said ribs slidingly engaging respective ones of said guide members, said panel also having on its rearward edge a cross-member secured to the upper surfaces of said ribs, said cross-member having laterally projecting ends which engage respective ones of said guideway means;

said panel being adapted to be moved to a partially forward position wherein said laterally projecting ends are retained within said guideway means while said two outermost ribs provide a cantilever support for said panel on said guide members, said panel thereby serving as a horizontal extension of said shelf,

said guideway means extending forwardly at least to the forward edge of said shelf and having forward stops thereon, whereby said panel may also be moved to a fully forward position and then pivoted upward into a vertical position with said laterally projecting ends of said cross-member being still retained within said guideway means by said forward stops; and

latch means cooperatively associated with said side walls and with the forward edge of said panel for latching said panel in its vertical position.

2. Material handling apparatus as in claim 1 which is a foldable cart including a rear wall supported on a pair of wheels; said side walls being pivotally attached to corresponding edges of said rear wall, and each of said side walls having a wheel supporting its outer edge.

3. Material handling apparatus as in claim 2 which includes a pair of vertically spaced shelves having their rearward sides pivotally secured to said rear wall, said panel being stored beneath the upper one of said shelves.

4. A shelf structure comprising:

a normally horizontally disposed rectangular shelf having beneath its respective ends horizontal guideway means extending parallel to the shelf ends, and also having a pair of horizontal guide members disposed beneath said shelf at the forward edge thereof and disposed inwardly from and beneath the respective guideway means;

a movable panel adapted to be supported from said guideway means and said guide members in a stored position beneath said shelf, said panel being of rectangular configuration with laterally projecting posts on its rearward edge;

the ends of said panel being slidingly supported upon respective ones of said guide members, and said projecting posts on the rearward edge of said panel being slidingly engaged within corresponding ones of said guideway means;

said guideway means extending forwardly at least to the forward edge of said shelf and having front stop means thereon adapted to retain said posts in a forward position of said panel;

whereby said panel may be entirely stored beneath said shelf, or may be moved to a partially forward position to provide a shelf extension with said panel ends receiving cantilever support from said guide members, but the removal of said panel from said shelf is prevented by said front stop means.

5. The shelf structure of claim 4 wherein said posts are pivotal in said front stop means so that said panel may be rotated to a vertical position enclosing the space above said shelf.

6. The shelf structure of claim 4 wherein said panel and guideway means have interengaging stop means which prevent said panel from being moved out to an extended position unless the front edge thereof is first raised upward to disengage said stop means.

7. A foldable material handling cart comprising:

a rear wall supported on a pair of wheels;

a pair of side walls pivotally attached to corresponding edges of said rear wall, each of said side walls having a wheel supporting its outer edge, said side walls being pivotable between one position in which they are parallel to each other and perpendicular to said rear wall, and another position in which they are folded back towards the rear wall;

a pair of vertically spaced shelves having their rearward sides pivotally secured to said rear wall, said shelves being adapted to be supported by said side walls in said first position of said side walls and being pivotable upward against said rear wall prior to the folding of said side walls towards said rear wall; and

a movable panel associated with one of said shelves, said movable panel being slidably supported on means carried beneath said shelf said means comprising horizontal guideway means carried beneath respective ends of said shelf and extending parallel to the respective side walls, a pair of horizontal guide members supported from respective ones of said side walls at the front edges thereof and being disposed inwardly from and beneath the respective guideway means, the ends of said panel being slidingly supported on said guide members and the rearward edge of said panel having laterally projecting posts slidably supported within said guideway means, said movable panel being normally stored beneath said shelf, and being movable to a partially forward position in which said panel provides a shelf extension, said panel when moved to its fully forward position being also upwardly pivotable relative to the associated shelf and having means associated with the ends of said panel for securing same to respective ones of said side walls to thereby enclose the space above said shelf.