The present invention relates generally to an exterior enclosure of a product vending machine as well as a method of construction of such exterior enclosures. The enclosure is constructed of homopolymer and/or copolymer, preferably a thermal plastic such as polypropylene, material. Generally, the construction of the enclosures is achieved by either welding or bending, or both, one or more sheets of the homopolymer and/or copolymer polypropylene material into a desired shape of a product vending machine. Various additionally homopolymer and/or copolymer polypropylene segments may be welded to the overall cabinet structure to create shelves and or supports for various internal vending machine components such as refrigeration units, a user interface, product holding devices or electromechanical components and the like. The various product vending components may also be secured directly to the polypropylene enclosure, shelves and/or support segments.
Typical vending machine enclosures for vending and dispensing equipment are constructed using sheet metal to form the enclosures. The sheet metal is mechanically fastened together and/or welded using traditional metal welding techniques. Such metal enclosures provided the structure necessary for maintaining products in a controlled environment, and prevent theft of products. In order to produce the sheet metal members economically, large and costly capital equipment is required such as turret presses, shears, and press breaks.
Traditional metal materials used for enclosures, usually steel and sometimes aluminum, are very strong. However, they are also relatively heavy materials, and therefore the material thickness of the enclosure members is limited for practical use concerning enclosure weight (as well as material cost). It is not uncommon for vending machine enclosures to be six feet in height and several feet wide and deep. For enclosures of this size, the thickness of the sheet metal members is necessarily made thin, and despite the material strength of metals, the thin material sections are structurally weak. This is often times mitigated by welding or fastening additional metal members to add strength. However, this adds to the overall cost of the enclosure.
In construction, multiple thin enclosure members are welded and/or fastened together to achieve the strength required for the enclosure. The process of metal welding requires the welder to undergo extensive training and posses a very high skill level to properly execute the technique. The mechanical fastening process requires additional parts such as screws, rivets, etc. which add to the cost of the enclosure and typically do not create as strong a joint as welding. Also, utilizing metal as the primary structural component adds significant weight to the overall vending machine. Metal enclosures further require additional painting or plastic covers in order to make them aesthetically attractive to customers as well as to prevent oxidation and corrosion.
For practical applications, sheet metal enclosures are restricted in their shape to square or angular geometry. This is due to a number of factors: the equipment and processes for creating complex geometry or surface contours on large sheet metal members is often cost prohibitive; the process for joining complexly contoured sheet metal shapes is difficult; and the minimal thickness of the sheet metal members does not allow for any substantial edge finishing or embellishment (bevels, radii, high relief engraved designs etc.). The manufacturing process for production volumes of sheet metal enclosures requires several sets of permanent tooling to produce the geometric features of the enclosure, features such as holes, slots, bends etc., in a cost effective manner. Therefore, design changes for sheet metal enclosures are costly, requiring modification to the permanent tooling, or the creation of new tools altogether.
The present invention solves the foregoing problems through the utilization of a unique structural material as well as a unique method of manufacture in the production of product vending machines. The present invention generally pertains to an enclosure constructed from homopolymer and/or copolymer, preferably a thermal plastic such as polypropylene, members and a method of construction therefore. Particularly, some embodiments of such enclosures are utilized in the construction of vending machines, product dispensing machines and the like. In certain embodiments, the polypropylene members used for the enclosure material are comprised entirely of homopolymer polypropylene, or entirely of copolymer polypropylene, or a combination of homopolymer and copolymer polypropylene members may be used.
Embodiments of the present invention provide for the polypropylene members utilized in the manufacture of the enclosure to be joined by hot gas (typically air or nitrogen) welding or extrusion welding. In the joining process, the plastic members are, in some embodiments, welded together to form a unitary, structure without the utilization of fasteners or brackets. The construction of the enclosure also reduces the appearance of welding beads which are typically found when two or more sections of metal are joined together, as the welding joints created in the construction of the vending machine cabinets are capable of being substantially ground down and smoothed to reduce their profile.
Alternately, in some embodiments, heat bending of a single flat polypropylene sheet is utilized to create the multiple facets of an enclosure. In creating an enclosure utilizing a single sheet of material, it is preferable that a groove is cut into the material at the bending location. The groove facilitates the bending of the material at the proper location and allows for a tight bend radius by minimizing the material displaced at the inside joint of the bend. Heated bending also eliminates the need for additional welding as the heated material on the inside of the bend fuses together upon completion of the heated bending process.
The utilization of polypropylene sheets in forming the enclosure structure also allows the structure to be formed into curves and other contoured shapes so that in some embodiments, complex geometry are capable of being added to the enclosure. The polypropylene enclosures naturally have strong resistance to weathering and chemicals, and they require no paint or coatings to protect their surface. Furthermore, embodiments provide for additional polypropylene members to be welded to the enclosure walls to create I-sections, T-sections, and/or U-sections to increase the structural strength and rigidity of the enclosure in high load bearing areas. Additional shelving and support elements are also be included in other embodiments. Thus while the overall structure of the cabinet is capable of being reinforced with a variety of other materials, it need not be. Embodiments provide for the overall structural integrity of the enclosure to be reliant on the polypropylene material.
Utilizing polypropylene material as a structural enclosure also provides for construction techniques and parameters that are simpler and more economical than those of traditional sheet metal enclosures. The quantity and cost of the equipment required to manufacture the polypropylene enclosures, such as CNC routers and bending bars are less that that required in the construction of metal enclosures as well. And while hot gas, or extrusion welding, and heated bending require training to properly execute, the welding and bend operations do not require that workers have the high a degree of skill necessary for welding metal. Consequently, labor costs for the production the polypropylene enclosure are reduced.
Many of the polypropylene enclosure walls are capable of being formed using heated bending of a single sheet, which reduces the number of separate parts needed for the enclosure. Eliminating the need for fasteners reduces the overall number of parts required for the enclosure. Additionally, polypropylene sheets are capable of being cut much easier and without specialized equipment than metals, which further reduces the manufacturing cost of the enclosure members.
Polypropylene is very light in comparison to metals—it has approximately 1/10th the density of steel and approximately ⅓rd the density of aluminum. Enclosures of polypropylene are capable of being produced in much greater material thickness than sheet metal and yet still have comparable weight as that of a sheet metal enclosure of the same size. The mechanical strength of the polypropylene enclosure is equivalent to and often greater than that of a sheet metal enclosure. Furthermore, polypropylene is much more impact resistant, and a polypropylene enclosure is capable of withstanding impacts that would permanently damage a sheet metal enclosure.
For example, impact to the wall of a sheet metal enclosure, possibly from being tipped over, kicked or hit, will result in denting and marring the enclosure. In such instances, it is impractical to repair the damage to the metal due to the relative difficulty of working with sheet metal. Particularly, a repair will generally require cutting, welding and grinding of the sheet metal, followed by painting to repair a damaged metal enclosure. However, due to the ease of working with polypropylene, embodiments of the present invention provide for a similarly damaged polypropylene enclosure to readily be repaired. The damaged section of the enclosure is capable of being cut away and a new section of polypropylene material is shaped and welded in place.
The polypropylene enclosure is particularly suitable to complex surface contours. The polypropylene members are capable of being formed into complex shapes using heat forming, and the shaped members are capable of being easily be welded to the enclosure structure using the plastic welding methods of the present invention. Since the polypropylene members are capable of being practically manufactured with a substantial thickness, and because it is efficiently machined, embodiments of the present invention provide for bevels and radii and other, more complex edge finishes to be added to the enclosure, and complex geometry to be cut into the enclosure walls themselves. This gives the polypropylene enclosure a greater number of both functional and aesthetic design options while maintaining a cost effective design. The manufacturing process for the polypropylene enclosure members also requires little to no permanent tooling. The members are capable of being efficiently manufactured on CNC cutting equipment, and if design changes are needed, a programming change—rather than a tooling change—is all that is required.
Another advantage that the thick walls of the polypropylene enclosure provides is the capability to effectively mount the internals of the vending and dispensing equipment (robotics, electronics, currency handling devices, etc.) directly to the walls by using self threading fasteners. Due to the thin material thickness of sheet metal members, sheet metal screws must be used, which are prone to stripping, or threaded inserts—which add cost to the equipment—are required to adequately fasten the internal devices. The polypropylene enclosure does not require threaded inserts, and provides a cost effective means to securely mount the internal devices.
Throughout the specification, wherever practicable, like structures will be identified by like reference numbers.
In this description, references to “one embodiment,” “an embodiment,” or “embodiments” mean that the feature or features being referred to are included in at least one embodiment of the technology. Separate references to “one embodiment,” “an embodiment,” or “embodiments” in this description do not necessarily refer to the same embodiment and are also not mutually exclusive unless so stated or except as will be readily apparent to those skilled in the art from the description. For example, a feature, structure, act, etc. described in one embodiment may also be included in other embodiments, but is not necessarily included. Thus, the present technology can include a variety of combinations or integrations of the embodiments described herein.
Preferably in embodiments of the present invention, polypropylene material is utilized to create an enclosure of a vending machine. It is also preferable that a homopolymer is utilized to create the exterior of the vending machine as its utilization results in a more aesthetically pleasing surface finish, withstands higher temperatures and is more rigid than a copolymer. A first method of constructing the enclosure begins with multiple sheets of polypropylene material. In some embodiments, the sheets are precast into particular desired shapes, or in alternative embodiments, are cut from a larger sheet into desired shapes. In the most basic embodiments of an enclosure, such as a typical rectangular box design shown in an exploded view in
With reference to
While embodiments of the present invention provide for other fasteners than screws to be used, the preferred screw fasteners provide some additional benefits. As shown in
In certain embodiments, upon securing the various vending machine components to the interior of the open box, the front panel 6, such as a front door, is added to finish the enclosure 200 as shown in, for example
In the event that a part of the enclosure is damaged, either during construction or once the enclosure is placed in the field, embodiments of the present invention provide for the damaged enclosure to be easily repaired. In certain embodiments, to repair a damaged panel, the damaged section is cut away from the overall enclosure. A new, replacement panel (or panels) is cut from sheets of polypropylene material to fit the section that was cut away. In some embodiments, a CNC router is programed to cut or carve the necessary replacement holes, slots, openings or engraving designs into the replacement panel, so as to mimic those design elements removed along with the damaged section. Embodiments then provide for the replacement section to then be welded to the enclosure panels in the proper orientation. Thus, the damaged section is removed, and a replacement section added in a relatively seamless manner, virtually eliminating the evidence of the damaged section. The enclosure is then operable to be placed back into service in the field with little to no aesthetically off-putting signs of damage, without the need to scrap, salvage and rebuild a new enclosure, and without the need to employ highly skilled labor.
Alternately, in some embodiments, a heat bending process, preferably in combination with the hot gas or extrusion welding process, is utilized to construct the enclosure. The heat bending process begins with a sheet of polypropylene material that is formed or cut into a geometric shape that when bent properly, forms an appropriately sized and proportioned elements of the enclosure. Using a traditional rectangular box style enclosure as an example, the process begins with a large rectangular shape.
Similar to the construction utilizing multiple panels, in some embodiments, the single sheet of polypropylene is further cut to provide holes, slots, vents, other openings or engraved designs. Preferably, a CNC router is programed so as to perform the proper cutting/routing in the single sheet of material. Once the necessary holes and designs have been formed, embodiments provide for the material to be bent into the proper shape. In certain embodiments to bend the sheet without damaging or breaking it, heat bars are used to heat the material along a bend line. A heat bar is an elongated bar that is capable of being heated to a temperature sufficient to soften the polypropylene material when the heat bar is placed in close proximity to or placed directly against the polypropylene material. Such heat bars are known devices. Preferably the heat bars are raised to a temperature of between 500 and 600 degrees Fahrenheit depending on the specific homopolymer or copolymer polypropylene material to be bent. The heat bars are applied to the polypropylene material so as to soften it in preparation for bending.
Once softened, preferably to the point where the material has melted, embodiments provide for the polypropylene material to be bent to the desired shape. For example, in certain embodiments heat bars are applied along junction lines that form the joints between the back and sides of the enclosure. The sides are then bent such that they each come perpendicular to the back to form an open “U” shape. The top and bottom are then welded to the open “U” shape to form an open box. The connection points between the sides and back are thus concealed on the inside of the enclosure and the only hot gas or extrusion welds is on the top and bottom of the enclosure. It is preferable that the back and sides of the vending machine are formed by heated bending such that the bending weld is formed on the interior of the cabinet while the top and bottom are welded onto the back and sides utilizing hot gas and/or extrusion welding. Formation of the cabinet according to the forgoing reduces the use of visible welds, regulating the visible welds to the very top and very bottom of the machine where they are unlikely to be observed by a vending machine customer. In some embodiments, the front door is also formed similar to as described above with respect to the open box and then secured to the open box. Such construction is generally depicted in the accompanying
Thus, while one method of forming the enclosure begins with six sheets of material and the various sheets are welded together, embodiments provide for a similar enclosure to be formed using a combination of bending and welding. Referring again to
To achieve square or substantially square corners, or otherwise to achieve curves with tight radii, it is preferable in some embodiments of the present invention that a groove is cut into the polypropylene material along the desired bend line. Referring now to
Once the basic shape of the enclosure has been achieved, the various components of the vending machine are added to the enclosure all as described above. Additionally, a front panel is added to complete the enclosure, and damaged sections are fixed also as described above. It should also be appreciated that, regardless of the method utilized to form the basic shape of the enclosure, additional polypropylene elements are capable of being efficiently added to the enclosure. For example, as shown in
Although the present invention has been described in terms of the preferred embodiments, it is to be understood that such disclosure is not intended to be limiting. Various alterations and modifications will be readily apparent to those of skill in the art. Accordingly, it is intended that the appended claims be interpreted as covering all alterations and modifications as fall within the spirit and scope of the invention.
This application claims priority to U.S. Provisional Application Ser. No. 61/694,996 filed Aug. 30, 2012, the entirety of which is incorporated herein by this reference.