Patent Publication Number: US-5834690-A

Title: Spatter, dust and rain-proof plastic safety case intended for extension cord plugging

Description:
The invention relates to a case intended for safe covering male and female extension cord plug connections, especially for outdoors use to connect electrical droven hand tools and portable apparatus such as vacuum cleaners to the mains. Problems possibly occuring are well-known, for example 
     ease disconnecting by cord tension; 
     easely accessibility by infants; 
     short circuiting caused by spattering or rain; 
     gutter-water and soggy swards; 
     corroded electrodes in the long run. 
     The case according to the invention is designed to avoid all these dangerous situations and consists of a nearly cylindrical tube with hemispherical fronts. The container is partited in a upper and lower part in a plane coinciding with its longitudinal centerline, while both parts are connected to each other by a hinge-joint, being a thin material layer created during the injection molding process. 
     After being closed by a click fastener system, the case parts are effectually secured. 
     Adults are enabled to unbold by simultaneously putting the thumb into the free counter-sink space on the shell circumference near it and pulling the grip. 
     For safety reasons construction details, dimensions and required force are such as to make this handling impossible for infants. 
     Waterproof plug connections already on the market and guaranteed for under water use as well, are serving a different purpose and subjected to governmental requirments and rules, as such not competitive with the case according to this invention which is adapt for domestic use in circumstances where spatter and rain-proof sealing is considered as very essential to protect users of portable current consumers against electric shock which can be fatally. 
     Short circuiting can also be caused by corroded electrodes due to penetrating moisture and wet when extension cords are outdoors used and that is where the invention emphatic provides for as well. 
     Plug cases not equiped with this provision do not meet basic safety secure against danger being connected with the use of electrical tools and equipment in the open air under bad wether conditions an/or dusty enviromental conditions. For said reasons the innovative vallue of the case according to the invention shall be concentrated to the lapping sealing along the contacting surfaces of upper and lower case part in closed position, especially at the spot of areas where one sealing construction changes into another, for example on either side of the hinge joint where small adjoining square rubber gaskets guarrantee for uninterrupted sealing, keeping dash water, spattering and rain away from that wet penetration sensitive area. 
     Although the gaskets in the circumference of the partited hemisphericals of the two case parts are accordingly the male and female type, the rubber sealing opposite the hinge does have its base molded to recessed edges, necessarily due to the click fastening system which is situated in the same plane. 
     Self-evidently the sealing along those edges is going to be male and female like also while securing the clasp and finaly the case becomes closed, resulting in an uninterrupted sealing, jointing with those of the end closures. 
     Resumptionive it may be ascertained that along the edges of both case halfs a sound sealing condition is realized. 
     Sealing of the cable inside the nozzle is attained by means of a internal rubber labyrinth arranged in such a way as to allow diffenent cable thicknesses, leaving the sealing behaviour unimpeded in consequence of a converging bore. 
     For each cable thickness there will be at least two active pairs of semi-circular bored rubber partition skirts available. 
     It has to be mentioned that the material flexibility of these skirts is also defining for optimal cable sealing results. 
     This sealing nozzles contributes essentially to the overall sealing behaviour of the case according to this invention. 
     Safe plug connection in circumstances where electricity and water are used simultaneously can be referred to as one of the most important applications for the invention, for example when somebody is handling the garden-hose outside while another one is at work on vacuum cleaning the inside of a car at the same time. 
     Other applications worthy of being recorded are Christmas tree lighting when outdoors and electricity sypply for caravans; moreover for all extension cord plug-in purpose for general use. 
    
    
     One embodiment of the invention shall be explained by way of example in which less relevant details are emitted for the sake of clearness, with reference to the accompanying drawings, in which: 
     FIG. 1 represents a view in the fully opened case, with male and female plug in position, longitudinal fixed by means of an adjustable half open seat, on its sliding side provided with tooths, corresponding with those molded inside the case bottom, while the cleats in the contra half this position maintain as long as the case remains secuted. 
     FIG. 2 represents a front view according to arrow &#34;P&#34; of the opened case. In this drawing dotted lines to trace invisible backwards laying construction details are consciously omitted, just like the out lines of the plug which should be partly visible, in order to avoid confusing. 
     The adjustable seat outlines are hided by one of the fixed part-partition plates molded to the front closures of the bottom part and coinciding with its tangent line. 
     The injection molded hinge between upper and lower part as well as the oubolted fastener-hinge are clearly visible in this view. 
     FIG. 3 represents a side view of the case when closed. 
     FIG. 4 the same, however with unbolded cross sectional drawn click-fastener detail. 
     FIG. 5 shows the bottom part of the adjustable half open seat, with which the combined plug connection can be fixed, independent its shape and dimensions as far as situated within the limitations given by the internal housing dimenssions. 
     FIG. 6 represents a front view of the adjustable seat, provided with a slotted hole for cable transit, corresponding with the slotted hole in the fixed part partition plate coinciding with the front tangent line. 
     FIG. 7 represents a detail of the labyrinth sealing for cable transit, seen in upper view. 
     FIG. 8 the same, however in the front view. 
     FIG. 9 gives a cross sectional detail of the hard plastic male and medium hard rubber female fasket construction in the circumference of the hemispherical fronts, with the conical shaped male part shown in dotted lines. 
     FIG. 10 represents a construction detail of the sealing opposit the hinge in the situation before the click system became fastened. 
     FIG. 11 shows the labyrinth sealing construction as fitted into the cable nozzle and its converging wise bored partitions. 
     FIG. 12 shows one of the small rubber squares on either side of the hinge; apparently a minor detail however very essential for adequate sealing with regard to the lapping function between hinge and partited hemispherical front gaskets, keeping the penetrating moisture, wet and dust away. 
    
    
     In order to avoid misunderstandings, firstly construction of the case itself shall be described in detail. Just necessarily mentioning sealing provisions which will be accentuated in detail afterwards. 
     CASE DESIGN: 
     The lower case half 1, being the part in which the plug combination is fitted, is provided with semi-hemispheres 2, each with semicircular labyrinth sealings 3 in the center. 
     By means of the hinge 4 (being a small and thin material layer, created during the injection molding process), the lower case half 1 is jointed to the upper case half 5 and provided with semihemispheres 6, though these parts do have labyrinth sealings 3, seamless jointing the grooved rubber gasket 7 along the circumferential edges of the semi-hemispherical front closures 6. The grooved rubber gasket 7 is corresponding with the ledge 8, molded to the semi-hemispherical end closures 2. 
     Positioning of plug combination 9 by means of the adjustable seat 10 by moving this seat in the direction of the end partition plate 12, which handling needs the positive toothing 11, molded to the bottom of case half 1, while the cable 13 is seated on the labyrinth sealing half 3. 
     The cams 14 are intended to avoid obliqueness of seat 10. The way in which the ledge 8, molded to the front edges, is corresponding with the groof 15 which is injection molded into the rubber gasket 7 of the semi-hemispherical fronts 6, is in accordance with the way in which the ledge 16 of the lower case part 1 corresponds with the sealing opposite the hinge on the edge of the upper case part 5, after closing and securing both halfs by means of clast 17, finaly also forming a male and female type sealing. In the bolted condition--that means the situation existing as soon as the case halfs 1 and 5 are closed, after positioning of the plug combination 9 and firmly pressing the clast 17 with its cam into the corresponding free space 19 in longitudinal direction of the upper case half 5--the overall sealing can be described as follows: 
     SEALING: 
     The sealing properties of the case according to the invention is very essential for its functioning under all conditions for which it is designed for, especially bad wether and less ideal environmental conditions. 
     Otherwise the expected sheltering for outdoors use of plugging extension cords will just deceptively ends in. Can be even more dangerous than taking no measures at all| 
     In order to meet the aforesaid requirements the fabrication methode is such as to achieve fusing rubber gasket and plastic housing material in a second preheated mould which results in a much higher precicion grade compared with cold molding or hot vulcanizing procedures outside the mould. 
     The ledge 8 sinks with his bevelled side into the rubber groove 15 of the sealing gasket 7, as described above, hot applicated to the edges of the semi-hemispherical end closures 6. 
     The rubber gasket 20, jointed to rubber gasket 7, is recessed constructed in such a way that, after securing by closing and click fastening, the circular cross sectional form nearly remains as original and no parts are sticking out. 
     However, in closed condition an uninterrupted sealing surface exist because of the profile 20 which joints the grooved rubber sealing 7. This groove 7 is provided with the same recessed construction as the upper case half 5. 
     Along the small strip surface on the lower case part 1 (adjacent to hinge 24), the clasp 17 itself shall touch the outside surface of the longtudinal gasket 20, in this way effectuating a triangle sealing function along the closing side between the edges of the semi-hemispherical end closures 2 and 6; a function as it were added to its bolting and securing functioning. 
     The corresponding semi-circular labyrinth gaskets 3 do seal the cables 13 at least such as to achieve sufficient tightness, each pair acting like an orifice. 
     For the transition area on either side of self sealing hinge 4, a small rubber square 22 is provided which, moulded to the main grooved rubber gasket 7 on the semi-himispherical fronts 6, takes care for the sealing gap between both systems. 
     When this measure should be deleted, leakage will surely occur. This and above mentioned and described sealing details are very characteristic for the overall tightness of the case according to the invention. An invention intended for safe outdoors use of extension cords with regard to the male and female plug connections, wherefore sealing behaviour got much attention, especially when compared with cases serving the same purpose and already in use, but with different construction details. 
     The free thumb space 23 in the upper case 5 facilitates ease unbolting of the click fastener 17, also called clasp, but the required force is such as to make that handling impossible for infants and smaller children in general.