Patent Description:
The present invention relates to stackable storage container systems, including systems which are handheld for joint transport or which include a plurality of storage containers which may be secured to each other for joint movement by a wheeled cart.

Stackable storage containers are known, for example, the rolling container assembly shown in <CIT> and <CIT>. The assembly disclosed therein includes a base storage container which is disposable on a cart which is provided with wheels and an integral handle system. At least one further storage container may be removably attached on top of the base container, allowing for multiple containers to be jointly transported. The mechanism for attaching the containers to each other may include a stacking latch mechanism, for example, as shown in <CIT>. The mechanism includes a spring loaded pivotable latch having a hook disposed on the lid of the container and a step formed on the lower housing of the container. The latch is spring biased towards an inward position. When the base of a second such container is disposed on a first such container the step of the second container contacts the hook and pushes the latch outwardly to allow the step to pass by. Once the step has cleared the hook, the latch moves inwardly under the spring bias so as to dispose the hook over the step and thereby secure the containers together.

<CIT> discloses a stackable mobile unit with drawers and a detachable dust suction system and shows the preamble of claim <NUM>.

<CIT> discloses a stackable toolbox and vacuum cleaner. <CIT> discloses an industrial vacuum cleaner with a power tool extension having power feed cables with end sockets for power tools. <CIT> discloses a storage unit with light emitting components. <CIT> discloses a stackable suitcase with a connecting device.

In one embodiment the invention is directed to a power outlet box comprising a housing including an opening. A rotatable drum (<NUM>) is disposed in the outlet box housing. A power cord is windable about the rotatable drum and includes an AC plug at one end. The power cord is disposed through the opening and is extendable with the drum rotating in an unwinding direction. At least one power outlet is disposed on the housing and is electrically powered by the power cord when the power cord is inserted in a wall outlet. An outlet box latch is disposed along one side of the outlet box housing. The outlet box latch is removably disposable over a step formed in a second housing to thereby removably secure the second housing to the outlet box housing.

In a second embodiment, the invention is directed to a stackable container system including a power outlet box and a storage container. The power outlet box includes an outlet box housing including an opening, a rotatable drum disposed in the outlet box housing, and a power cord windable about the rotatable drum and including an AC plug at one end. The power cord is disposed through the opening and is extendable with the drum rotating in an unwinding direction. The invention further includes at least one power outlet disposed on the outlet box housing and electrically powered by the power cord when the plug is inserted in a wall outlet. The storage container further includes a plurality of storage container walls defining an open upper surface and an interior storage volume and a storage container handle secured to the storage container and rotatable between a position above the open upper surface and a position along at least one of the storage container walls. The outlet box housing is removably disposable on the storage container walls so as to be supported in the open upper surface and above the interior storage volume with the storage container and power outlet box jointly carriable by the storage container handle.

In a third embodiment, the invention is directed to a stackable container system including a power outlet box and a storage container. The power outlet box includes an outlet box housing having an opening, a rotatable drum disposed in the outlet box housing and a power cord windable about the rotatable drum and including an AC plug at one end. The power cord is disposed through the opening and is extendable with the drum rotating in an unwinding direction. At least one power outlet is disposed on the outlet box housing and is electrically powered by the power cord when the AC plug is inserted in a wall outlet. The storage container includes a plurality of storage container walls defining an interior storage volume. The storage container and the power outlet box are removably securable to each other.

These and other objects, features, and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structure and the combination of parts will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, that the drawings are for the purpose of illustration and description only, and are not intended as a definition of the limits of the invention. In addition, it should be appreciated that structural features shown or described in any one embodiment herein can be used in other embodiments as well. As used in the specification and in the claims, the singular form of "a", "an", and "the" include plural references unless the context clearly dictates otherwise.

With reference to <FIG> stackable power outlet box <NUM> includes upper housing <NUM> disposed on lower housing <NUM> to enclose an interior volume. Circular interior wall <NUM> is disposed within and divides the interior volume into drum chamber <NUM> and electronics chamber <NUM>. Circular interior wall <NUM> includes vertical opening <NUM>(a) disposed therethrough. Stackable power outlet box <NUM> defines a pair of opposite and substantially parallel long sides <NUM>(b) and short sides <NUM>(a). Four electrical AC outlets <NUM> are disposed on lower housing <NUM> on one of short sides <NUM>(a) adjacent electronic chamber <NUM>. USB charging ports <NUM> are disposed on lower housing <NUM> below AC outlets <NUM> and are covered by USB port cover <NUM>. AC outlets <NUM> and USB ports <NUM> both provide electrical power and are jointly considered as power outlets. On/off switch <NUM> and overload reset button <NUM> are disposed on one of long sides <NUM>(b) along with pivotable carry handle <NUM>. AC cord <NUM> extends through a second short side <NUM>(a) and suitable electronics are provided to electrically link AC cord <NUM> to USB charging ports <NUM> and AC outlet ports <NUM> so as to provide current thereto, and is controlled by on/off switch <NUM>, as described further below. Electronics chamber cover <NUM>(a) is secured over electronics chamber <NUM>.

Stackable power outlet box <NUM> further includes latch system <NUM> disposed in a recessed area <NUM>(a) formed on upper housing <NUM> at a location above carry handle <NUM> on one long side <NUM>(b). Raised edge <NUM>(b) having a portion which overhangs the upper surface of upper housing <NUM> extends along and is formed on the upper surface of upper housing <NUM> on the opposite long side <NUM>(b). Lower housing <NUM> further includes two steps <NUM> formed on and projecting from a lower surface thereof. One step <NUM> is formed on one long side <NUM>(b) below carry handle <NUM> and the other step <NUM> is disposed on the other long side <NUM>(b) at a location below raised edge <NUM>(b) and opposite of first step <NUM>. Steps <NUM> each include lower and side walls extending from lower housing <NUM> to define an open volume. Cylindrical opening <NUM> is formed through the top of upper housing <NUM> substantially above drum chamber <NUM>.

Slip ring <NUM> is disposed within drum chamber <NUM> and includes a plurality of openings which are disposed about upwardly extending screw bosses formed on the inner surface of lower housing <NUM> and is secured to the inner surface via screws. Drum <NUM> is disposed within chamber <NUM> and includes central cylinder <NUM>(a) and upper and lower discs <NUM>(b) which define a cord winding volume therebetween. Slip ring <NUM> includes upper projection <NUM>(a) which fits within lower disc <NUM>(b) so as to allow central cylinder <NUM>(a) to be rotatably disposed on the upper surface of slip ring <NUM>. Central cylinder <NUM>(a) includes a plurality of vertically extending openings <NUM>(c). Winding handle body <NUM> is generally cylindrical and is vertically slidably disposed within central cylinder <NUM>(a) and includes spring tabs <NUM>(a) which fit within vertical openings <NUM>(c) to allow winding handle body <NUM> to be moved vertically relative to cylinder <NUM>(a) for a limited extent while also mechanically joining winding handle body <NUM> and central cylinder <NUM>(a) so that they jointly rotate with each other within drum chamber <NUM>.

AC cord <NUM> is wrapped about drum central cylinder <NUM>(a) and extends through opening <NUM>(a) of circular interior wall <NUM> and through an opening in short side wall <NUM>(a). Recess <NUM>(a) is formed in short side wall <NUM>(a) into which the trailing end of AC cord <NUM> and AC plug <NUM>(a) may be secured when power outlet box <NUM> is not in use. AC cord <NUM> is electrically linked at its opposite end to the electronics as described further below. AC cord <NUM> is also secured to drum <NUM> such that rotation of drum <NUM> allows AC cord <NUM> to be rewound. AC cord <NUM> may be unwound by pulling on the exposed end thereof which is exterior of lower housing <NUM>.

Cylindrical winding handle body <NUM> includes handle grips <NUM> formed on the upper surface thereof and which take the form of overhangs disposed in a recessed region. A plurality of spring tabs <NUM>(a) are formed about the lower periphery of cylindrical winding handle body <NUM>. When cylindrical winding handle body <NUM> is in its lower position handle grips <NUM> are exposed through cylindrical opening <NUM> in upper housing <NUM>. Pivot rod <NUM>(a) extends between handle grips <NUM>. Handle <NUM> includes openings which receive pivot rod <NUM>(a) and is thereby pivotably disposed on winding handle body <NUM> between a position in which it lies within a channel formed on the upper surface of winding handle body <NUM> and a position in which it is raised outward of the channel and into a winding position which lies at <NUM> degrees to its original position. Handle <NUM> includes projection <NUM> and grip knob <NUM> is disposed thereon.

With reference to <FIG> the functioning of handle <NUM>, handle winding body <NUM> and drum <NUM> are shown. AC power cord <NUM> may be extended by pulling it outwardly from side <NUM>(a) to the desired extent, with drum <NUM> rotating as necessary. Winding handle body <NUM> and handle <NUM> also rotate with drum <NUM> due to the mechanical connection of spring tabs <NUM>(a) disposed within vertical openings <NUM>(c). AC power cord plug <NUM>(a) may be plugged into an available power outlet to provide power to AC outlets <NUM> and USB ports <NUM>, which can be used to power external devices such as power tools, phones or other devices which make use of AC power or a USB cable. As shown in <FIG>, winding handle body <NUM> remains in its initial lower position where it is fully retracted into central cylinder <NUM>(a) of drum <NUM>. When it desired to retract AC power cord <NUM> back into power outlet box <NUM>, as shown in <FIG>, winding handle body <NUM> is raised by use of handle grips <NUM> so as to move it vertically upward through opening <NUM>, with spring tabs <NUM>(a) riding upwardly in vertical openings <NUM>(a). In <FIG>, handle <NUM> is free from the upper surface of upper housing <NUM> and has been pivoted to its winding position about pivot rod <NUM>(a). Knob <NUM> can then be gripped to rotate winding handle body <NUM> and thus drum <NUM> to retract AC power cord <NUM> into power outlet box <NUM>. When AC cord <NUM> is fully extended, power outlet box <NUM> may be disposed a significant distance from an available AC wall outlet, for example, AC power cord <NUM> may be fifty feet long.

<FIG> show the manner in which AC cord <NUM> is mechanically linked to drum <NUM> to allow for extension and retraction of thereof, and the manner in which AC cord <NUM> is electrically linked with each of AC outlets <NUM> and USB charging ports <NUM> so that stackable power outlet box <NUM> may act as a power strip to provide power to multiple AC devices as well as to provide charging to devices with corresponding USB ports. AC cord <NUM> extends through opening <NUM>(e) formed through central cylinder <NUM>(a) and is secured thereon via cable stopper <NUM>(f) which is both secured onto the exterior surface of AC cord <NUM> and lodged within the central interior volume defined by central cylinder <NUM>(a) and rests against the inner surface of central cylinder <NUM>(a). Cable stopper <NUM>(f) prevents the inner end of AC cord <NUM> from becoming disconnected from central cylinder <NUM>(a) during unwinding and provides a physical connection between AC cord <NUM> and central cylinder <NUM>(a) during winding. Standard electrical wires <NUM>(b) of AC cord <NUM> extend from the inner end and are connected to conducting elements disposed in three cylindrical openings <NUM>(g) which are defined by cylindrical walls extending downwardly from the lower surface of lower surface <NUM>(b) of drum <NUM>. Standard electrical wires <NUM> are disposed within lower housing <NUM> and one end of each wire <NUM> is electrically connected to conductors on the ends of cylinders <NUM>(b) which are defined by walls projecting upwardly from the surface of slip ring <NUM> radially within upper projection <NUM>(a). At the other end, wires <NUM> extend into electronics housing <NUM> and are linked via overload reset button <NUM> and on/off switch <NUM> to AC outlets <NUM> and USB charging ports <NUM> in a parallel arrangement so as to provide power to said outlet and ports. Cylinders <NUM>(b) are disposed within corresponding cylindrical openings <NUM>(g) so as to electrically connect each of wires <NUM>(b) to a corresponding wire <NUM>, with the electrical connection maintained throughout the rotation of drum <NUM> relative to slip ring <NUM> due to the cylindrical shape. That is, regardless of the angular location of drum <NUM> relative to slip ring <NUM> resulting from the winding/unwinding of AC cord <NUM>, the electrical connection between AC cord <NUM> and AC outlets <NUM> and USB charging ports <NUM> is maintained. Reset button <NUM> may be activated to reset the electronics should a conventional internal circuit breaker be opened due to excess current draw.

With reference to <FIG>, latch mechanism <NUM> includes stacking latch body <NUM> which is pivotably mounted about stacking pins <NUM>(a) and <NUM>(b), which are inserted through lateral left and right openings formed in stacking latch body <NUM>. Stacking pins <NUM>(a) and <NUM>(b) are further inserted at their opposite ends into holes formed in recessed area <NUM>(a) so as to pivotably mount stacking latch body <NUM> onto upper housing <NUM>. Stacking latch spring <NUM> includes lateral coil sections <NUM>(a) and <NUM>(b) and bridge area <NUM>(c). Lateral coil sections <NUM>(a) and <NUM>(b) are fitted onto stacking pins <NUM>(a) and <NUM>(b) respectively, and stacking latch body <NUM> is assembled into recessed area <NUM>(a) with bridge section <NUM>(c) rotated downwardly and trapped against the body of upper housing <NUM> so as to provide a spring bias outwardly on stacking latch body <NUM> adjacent the lower boundary thereof. Therefore, the upper edge of stacking latch body <NUM> is biased inwardly relative to upper housing <NUM>.

Stacking latch body <NUM> further includes first and second primary hooks <NUM>(a) and <NUM>(b) extending inwardly from the upper edge thereof, with vertical through opening <NUM>(c) formed therebetween. First and second primary hooks <NUM>(a) and <NUM>(b) slope downwardly in the inward direction relative to upper housing <NUM>. Intermediate projecting surface <NUM> extends inwardly from a central location of stacking latch body <NUM> and has lateral openings <NUM>(a) formed therethrough to receive stacking pins <NUM>(a) and <NUM>(b), as well vertical through opening <NUM>(b) which is aligned with and is vertically below opening <NUM>(c). Lower projecting ledge <NUM> is disposed below intermediate projecting surface <NUM> and includes spring support surface <NUM>(a) having circular spring opening <NUM>(d) therein. Spring support surface <NUM>(a) is disposed below and in line with vertical opening <NUM>(b) and vertical opening <NUM>(c). Through hole <NUM> is defined within lower projecting ledge <NUM> inward of spring support surface <NUM>(a). Catch ledges <NUM>(b) extend inwardly from stacking latch body <NUM> and downwardly from the lower surface of lower projecting ledge <NUM>, laterally outward of through hole <NUM>. Stopper support surface <NUM>(c) extends inwardly from stacking latch body <NUM> below vertical opening <NUM>(b) and through hole <NUM>, laterally inward of catch ledges <NUM>(b).

Stacking latch stopper <NUM> includes a main body having integrally formed spring tabs <NUM>(a) on either side thereof and upper contact surface <NUM>(b). Coil spring <NUM> is disposed within a central volume of stacking latch stopper <NUM> with its lower end disposed within circular spring opening <NUM>(d). Stacking latch stopper <NUM> is disposed on latch body <NUM> by being fitted through openings <NUM>(c) and <NUM>(c), with tabs <NUM>(a) being forced radially inward to allow them to pass through hole <NUM>. Tabs <NUM>(a) then flexing outwardly to catch beneath catch ledges <NUM>(b) to secure stopper <NUM> in place on stacking latch body <NUM>, with coil spring <NUM> biasing latch stopper <NUM> upwardly such that tabs <NUM>(a) come into contact with catch ledges <NUM>(b). Stopper support surface <NUM>(c) limits movement of latch stopper <NUM> downwardly and out of opening <NUM>(b). A slight clearance is maintained between the lower surface of latch stopper <NUM> and stopper support surface <NUM>(c) due to the upward bias of coil spring <NUM>.

With reference to <FIG>, storage container <NUM> forming part of the invention is disclosed. Storage container <NUM> includes step <NUM> which is substantially identical in structure to step <NUM> of stackable power outlet box <NUM> and which extends from a central lower surface of one side wall, in this case a long side wall, and latch mechanism <NUM> as described above with reference to stackable power outlet box <NUM> is disposed at the upper surface of the side wall. Though not shown, further step <NUM> would be formed on the opposite lower side wall. As shown, overhanging retaining hook ledge <NUM> is disposed on the upper side surface opposite latch mechanism <NUM>. Though not shown, a further latch mechanism <NUM> could be disposed on the opposite site wall in place of hook ledge <NUM>. Storage container <NUM> has an open top surface. Handle <NUM> is pivotably secured at opposite side walls of storage container <NUM>, in this case the short side walls. Handle <NUM> may be pivoted from a lower position for example as shown in <FIG> where it is located along the lower side of storage container <NUM> to an upper position as shown in <FIG> where it is located above the open top surface of storage container <NUM>. Sufficient clearance is provided so that power outlet box <NUM> may be disposed within the open upper surface of storage container <NUM> with handle <NUM> disposed there above so as to allow both storage container <NUM> and stackable power outlet box <NUM> to be simultaneously carried by a user holding handle <NUM>.

With further reference to <FIG>, stackable power outlet box <NUM> may be secured on container <NUM> in the configuration shown in <FIG> by disposing it into the upper open surface of container <NUM> which has similar overall dimensions. When power outlet box <NUM> is disposed on container <NUM>, one of steps <NUM> is secured under hook ledge <NUM> of storage container <NUM>, and the other of steps <NUM> contacts primary hooks <NUM>(a) and <NUM>(b) of latch mechanism <NUM> formed on container <NUM> and thereby forces the upper portion of stacking latch body <NUM> to pivot outwardly about stacking pins <NUM>(a) and <NUM>(b), against the inward bias of stacking latch spring <NUM>, and away from the upper open surface of container <NUM>. The outward movement is sufficient to allow step <NUM> to pass by primary hooks <NUM>(a) and <NUM>(b) and to come to rest on upper contact surface <NUM>(b) of stacking latch stopper <NUM> and intermediate projecting surface <NUM>. Simultaneously, primary hooks <NUM>(a) and <NUM>(b) are biased back inwardly by stacking latch spring <NUM> so as to rest over the upper surface of step <NUM>, thereby securing power outlet box <NUM> on top of container <NUM> so that it cannot move vertically off of container <NUM>, with the side surface of latch body <NUM> and hook ledge <NUM> precluding lateral motion. The contact of step <NUM> with upper surface <NUM>(b) of latch stopper <NUM> causes latch stopper <NUM> to move slightly downwardly against the upward spring bias provide by coil spring <NUM>, with its downward movement limited by stopper support surface <NUM>(c).

In order to release stackable power outlet box <NUM>, stacking latch body <NUM> is pushed inward at its lower portion so that the upper portion is again pivoted outwardly against the spring bias such that primary hooks <NUM>(a) and <NUM>(b) are moved to a location where they are not located above step <NUM>. Since primary hooks <NUM>(a) and <NUM>(b) are no longer in contact with step <NUM>, the upward bias of coil spring <NUM> against latch stopper <NUM> acts upon step <NUM> to causes a slight upward movement of step <NUM> and stackable power outlet box <NUM> such that step <NUM> is disposed inwardly of and at the same level as primary hooks <NUM>(a) and <NUM>(b), preventing them from returning to their latching position once the user pushes stacking latch body <NUM>. The user can then lift stackable power outlet box <NUM> off of container <NUM> without having to maintain inward pressure on stacking latch body <NUM>, and with opposite ledge <NUM> moving slightly inward and clear of hook ledge <NUM>.

Although the invention described above with respect to <FIG> included container <NUM> having latch mechanism <NUM> and hook ledge <NUM>, container <NUM> could also include a second latch mechanism <NUM> disposed in place of hook ledge <NUM>. Both latch mechanisms <NUM> would operate as described above when stackable power outlet box <NUM> is disposed on container <NUM>. Additionally although stackable power outlet box <NUM> was described above as being disposed upon container <NUM>, the reverse orientation is also possible. For example, as shown in <FIG>, container <NUM> can be disposed upon and secured to the upper surface of stackable power outlet box <NUM>. This is made possible by the fact that both stackable power outlet box <NUM> and container <NUM> have steps <NUM> or <NUM> formed on their lower edges and latch mechanisms <NUM> (or alternatively one latch mechanism <NUM> and one hook ledge <NUM>(b) or <NUM> disposed on their upper edges. ) In either orientation, handle <NUM> can be used to jointly transport container <NUM> and stackable power outlet box <NUM>.

With reference to <FIG>, a stackable storage system forming a further embodiment of the invention is disclosed. Stackable storage system <NUM> includes a plurality of stackable storage containers <NUM>(a), <NUM>(b) and <NUM>(c), of varying sizes, each of which includes a lid having latch mechanism <NUM> disposed thereon to secure the lid to the base of the storage container disposed thereon. Container <NUM>(a) is the lowest container of the stack and may be integrally formed with wheels <NUM> and an upright pull handle <NUM> to allow stackable storage system <NUM> to be transported by tilting and rolling. Alternatively, lowest container <NUM>(a) can be attachable to a wheeled carriage having an upright pull handle. Stackable power outlet box <NUM> can be disposed on top of upper container <NUM>(c) of the stack of containers, and secured thereto via latch mechanism <NUM> of container <NUM>(c) and step <NUM> of power outlet box <NUM>. A further container <NUM>(d) may be secured on top of power outlet box <NUM>. In each case, AC outlets <NUM> and USB charging ports <NUM> are available for use.

In the embodiment described with reference to <FIG> power outlet box <NUM> is formed to have a dimension of its short sides <NUM>(a) which is about half the width of containers <NUM>(a),<NUM>(b) and <NUM>(c). Therefore, power outlet box <NUM> is secured across the depth of the stack and extends about one half of the width, allowing stackable power outlet box <NUM> and storage container <NUM> (or a further half width container) to be stacked side by side on the top of container <NUM>(c). With reference to <FIG>, container <NUM>(c) includes raisable T-Bar <NUM> which is known in the prior art and has two overhanging latches which fit over steps <NUM> of power outlet box <NUM> or step <NUM> of storage container <NUM> in order to secure their laterally inner sides. The outer sides of power outlet box <NUM> and storage container <NUM> are secured by stacking latch mechanism <NUM> as described above. Though stackable power outlet box <NUM> is shown as disposed as the top most element of the stack, it could also be disposed within the stack, for example, between storage containers <NUM>(b) and <NUM>(c), in a side by side relationship with a half sized storage container.

With reference to <FIG> and <FIG>, a further embodiment of the invention is shown. Stackable power box <NUM> includes lower wall <NUM> extending around the lower periphery thereof at a radially inward location. Container <NUM> includes ridge <NUM> extending around the upper inner periphery thereof. Container <NUM> includes step <NUM>. Power outlet box <NUM> may be disposed upon container <NUM> by inserting lower wall <NUM> within ridge <NUM> to provide a friction fit. Power outlet box <NUM> also includes upper drive nut <NUM> which is linked to a drum similar to drum <NUM> described above. Winding handle <NUM> is attached to the drum via drive nut <NUM>. AC outlets <NUM> and USB ports <NUM> are disposed in the long side wall of power box <NUM>. In all other respects, power box <NUM> is identical to power outlet box <NUM> described above. As shown in <FIG>, drum <NUM> can be driven by power tool <NUM> such as a drill which is engaged with drive nut <NUM> to rewind AC cord <NUM>.

In a further embodiment, the power outlet box can be rewound by an on-board motor attached to drum <NUM>. Further, a battery may be disposed on power outlet box to power the electrical outlets. Alternatively, automated retraction may be provided by a spring.

In a further embodiment, assisted manual winding may be provided by using a gear.

In a further embodiment, a clutch mechanism may be provided to avoid winding in the wrong direction.

In a further embodiment, the power box may include a detachable AC cord which can be replace by an extension cord.

Claim 1:
A power outlet box (<NUM>) comprising:
an outlet box housing (<NUM>, <NUM>) including an opening;
a rotatable drum (<NUM>) disposed in said outlet box housing (<NUM>, <NUM>);
a power cord (<NUM>) windable about said rotatable drum (<NUM>) and including an AC plug (2a) at one end, said power cord (<NUM>) disposed through said opening and extendable with said drum (<NUM>) rotating in an unwinding direction;
at least one power outlet (<NUM>) disposed on said outlet box housing (<NUM>, <NUM>) and electrically powered by said power cord (<NUM>) when said AC plug (2a) is inserted in a wall outlet;
an outlet box housing latch (<NUM>) disposed along one side of said outlet box housing (<NUM>, <NUM>), wherein, said outlet box housing latch (<NUM>) is removably disposable over a step formed in a second housing to thereby removably secure the second housing to said outlet box housing (<NUM>, <NUM>); and
characterized in that the outlet box housing (<NUM>, <NUM>) includes an upper surface, and said rotatable drum (<NUM>) further comprises an integral axial member extending through the upper surface and includes a drivable head, and said axial member is drivable by an external power driver via said drivable head to drive the rotatable drum (<NUM>).