Abstract:
A self-contained ammunition round detection unit includes a housing with an indicator mounted within the housing. A probe is coupled to the indicator. A dual set of biasing elements are captivated within the housing. The dual set of biasing elements cooperate to retract the indicator in a biased state, and extend the indicator to indicate an ammunition round is present when the probe is at least partially retracted by contacting a surface of the ammunition round.

Description:
FIELD OF THE INVENTION 
     The present invention is generally related to product detectors, and, in particular, to an ammunition detector for indicating the presence of an ammunition round in a storage canister. 
     BACKGROUND OF THE INVENTION 
     Tank ammunition rounds are typically stored in individual shipping and storage canisters. When stored, up to about 30 such canisters are kept secured onto a single pallet. Since the shipping and storage canisters are recyclable, they are monitored for inventory purposes. In order to facilitate inventory tracking, full canisters are often loaded on the same pallet with empty canisters. Currently, there is no way to discern an empty canister from a loaded canister, except by opening the canister cover and visually inspecting the interior. 
     Unfortunately, there are significant drawbacks to visually inspecting for product. One such drawback is that most shipping and storage canisters are covered with an airtight seal. The airtight seal makes it cumbersome to remove the cover. Further, visual inspection of large canisters stacked high on a pallet is inherently awkward and time consuming. The inspector must literally look high and low, while pulling and replacing covers, until the inspection is complete. Further still, such inspections are inherently unreliable since there is no visible means of verifying the inspection results once all the covers have been replaced on an inspected pallet of containers. 
     SUMMARY OF THE INVENTION 
     The present invention provides a product detector having a top housing, where the top housing includes a top bore and a bottom bore. An indicator pin assembly tube is attached to the top housing. An indicator pin assembly has a top portion captively engaged to the top housing. The indicator pin assembly further includes an indicator button located at a top end, a first biasing device, and a probe. A first biasing device and the probe are captively engaged in the indicator pin assembly tube. The probe is slidingly engaged to the indicator button such that, when the probe is extended in a biased state, the indicator button is retracted, thereby also retracting the indicator cap. A second biasing mechanism is captivated within the indicator cap. The first and second biasing mechanisms cooperate to retract the indicator cap and extend the probe in the biased state. 
     It is a motivation of the present invention to provide an ammunition product canister detector that eliminates the need for removing a canister cover to determine the contents. 
     It is a further motivation of the invention to provide a detection device that mounts in a canister cover and contacts a product inside the canister. 
     It is a further motivation of the invention to provide a detection device where an indicator pin pops out if a product is contained within a canister, and is retracted if the canister is empty. 
     It is a further motivation of the invention to provide a detection device for an ammunition container that maintains an airtight seal in the container. 
     It is a further motivation of the present invention to provide a self-contained product detection unit that needs no external wires or mechanisms to detect product presence. An indicator protrudes from the detector when a product is present and a probe extends itself until a product is contacted. In a preferred embodiment, the movement of these two pieces is controlled by a dual set of biasing springs. One spring pushes the indicator pin out to indicate product and another spring returns the probe to an empty position. The location of the indicator pin is determined by the position of the product probe. The indicator pin and product probe are coupled by a connecting device. The connecting device allows the probe a much greater travel than the indicator pin. The greater travel of the probe detects a number of different products, of different lengths in a canister, yet the indicator pin only travels a predetermined distance. The predetermined distance is set to keep the indicator pin from protruding an excessive amount that could present a hazard. It also allows the button to be at a uniform height for ease of product determination. 
     Other objects, features and advantages of the present invention will become apparent to those skilled in the art through the description of the preferred embodiment, claims and drawings wherein like numerals refer to like elements. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cut away side view of one example of the product detector of the invention in a biased state. 
     FIG. 2 is a cut away side view of one example of the product detector of the invention in a retracted state. 
     FIG. 3 is a cut away side view of an alternate example of the product detector of the invention in a biased state. 
     FIG. 4 is a cut away side view of an alternate example of the product detector of the invention in a retracted state. 
     FIG. 5 is a cut away side view of an example of the product detector of the invention deployed in an ammunition canister including a spacer and a cushion. 
     FIG. 6 is a cut away side view of an example of the product detector of the invention deployed in an ammunition canister lacking spacers and cushions. 
     FIG. 7 is a side view of one example of another alternate embodiment of a product detector of the invention in a biased state. 
     FIG. 8 is a cut away side view of the example of the product detector shown in FIG.  7 . 
     FIG. 9 is a partial cross-sectional side view of one example of an indicator pin assembly constructed in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1, a cut away side view of one example of the product detector of the invention in a biased state is shown. The product detector  10  includes a top housing  12 , a first seal  13 , an indicator cap  14 , a probe spring  16 , a probe  18 , a second seal  22 , an indicator pin  24  and an indicator spring  26 . The product detector  10  is generally cylindrical having a central axis  5 . 
     Still referring to FIG. 1, the top housing  12  is preferably constructed of a plastic material. The first seal  13  and second seal  22  preferably comprise rubber. More preferably, the second seal  22  comprises a U-cup seal. Suitable U-cup seals are commercially available. The first seal  13  and second seal  22  are constructed to meet requirements for a maximum leak rate of 5 cc/minute when pressurized to about 3 p.s.i., when measured for at least 5 seconds. The top housing  12  has a top bore  7  through one side and a bottom bore  9  through the opposite end. The top housing  12  and top and bottom bores  7 ,  9  are substantially axially disposed around the central axis  5 . 
     Referring again to FIG. 1, an indicator pin assembly  55  includes an indicator pin having an indicator button  25 , top flared end  27 , and bottom flared end  29 . The indicator pin assembly also includes probe  18  and probe spring  16 . The indicator pin assembly  55  is assembled to the top housing  12  so that the indicator button  25  protrudes through the top and bottom housing bores  7 ,  9  respectively. The indicator pin  24  with probe spring  16  and probe  18  are captively engaged within indicator pin assembly tube  3 . The indicator pin assembly tube  3  is attached by means of a press fit or other known attaching mechanism to the top housing  12 , or may alternatively be made integrally to the top housing. The seal  22  is inserted into the bottom bore  9 . The indicator cap  14  is positioned in the top bore  7  together with an indicator spring  26 . The indicator cap  14  is press fitted or snap fitted onto the top flared end of the indicator pin  24 . The indicator spring  26  preferably comprises a standard compression spring having a lower spring constant or spring strength relative to the probe spring  16 . The pair of springs operate so that the product detector is biased with the probe  18  extended. 
     Continuing the description of the indicator pin assembly  55 , in one example embodiment, the probe  18  is substantially cylindrical and has a top bore  67  at one end and a bottom bore  69  at a second, opposing end. The top bore  67  stops at surface  19  having an aperture therein. The indicator button  25  includes flared end  29 . Flared end  29  is sized to snap fit into the aperture  41  of surface  19  so that the distal end of the indicator pin is captured within the bottom bore  69  of the probe  18 . The indicator pin is also inserted through probe spring  16  held between a retainer  17  and the surface  19 . The retainer  17  may be a flat annular part that also holds the seal  22  in place. In the absence of a counter force, the probe spring  16  bears against the surface  19  and retainer  17  so as to retract the indicator button  25 , thereby also retracting attached indicator cap  14 . 
     Referring now to FIG. 2, a cut away side view of one example of the product detector of the invention in a retracted state is shown. The product detector  10  is shown engaged into an ammunition container cover  30 . Stacked inside the container atop a cartridge bottom end  36  are a foam cushion  32 , a filler member  34 , and a spacer  35 . When probe  18  partially retracts due to contacting a product surface, the center pin  24  is extended. In operation, retraction of center pin  24  and probe  18  compresses probe spring  16 , thereby releasing plunger spring  26  that expands to extend indicator cap  14 . The extended indicator cap  14  thus gives a visual indication of the presence of a product in the container. In one example, the indicator cap or button may be distinguished by using an appropriate coloration such as red, green, yellow or other desired color. 
     Referring now to FIG. 3, a cut away side view of an alternate example of the product detector of the invention in a biased state is shown. The product detector  300  includes a top housing  312 , a first seal  313 , an indicator cap  314 , a probe spring  316 , a probe  318 , a seal  50 , an indicator pin  324  and an indicator spring  326 . The product detector  300  is generally cylindrical having a central axis  305 . 
     As in the preferred embodiment, the top housing  312  is preferably constructed of a plastic material. The first seal  313  and second seal  50  preferably comprise rubber. In contrast to the preferred embodiment, the seal  50  may comprise a conventional rubber O-ring or equivalent sealing mechanism. The top housing  312  has a top bore  307  through one side and a bottom bore  309  through the opposite end. The top housing  312  and top and bottom bores  307 ,  309  are substantially axially disposed around the central axis  305 . 
     The indicator pin assembly  355  is assembled to the top housing  312  so that the indicator button  325  with flared top end  327  protrudes through the top and bottom housing bores  307 ,  309  respectively. The indicator pin  324  with probe spring  316  and probe  318  are captively engaged in an indicator pin assembly tube  303 . The indicator pin assembly tube  303  may be integral with or attached by means, such as a press fit or other known attaching mechanism, to the top housing  312 . The indicator cap  314  is positioned in the top bore  307  together with a second biasing means  326 . The indicator cap  314  is press fitted, snap fitted or otherwise affixed onto the top flared end of the indicator pin  324 . The other end of indicator pin  324  is slid through aperture  341  and held in position by flared bottom end  329 . The second biasing means  326  preferably comprises a probe spring having a lower spring constant or spring strength relative to the first biasing means  316  so that the product detector is biased into a biased state with the probe  318  extended. 
     Referring now to FIG. 4, a cut away side view of an alternate example of the product detector  300  of the invention in a retracted state is shown. The alternate embodiment is constructed and operates substantially similarly to the preferred embodiment of FIG.  1 . 
     Referring now to FIG. 5, a cut away side view of an example of the product detector of the invention deployed in an ammunition canister including a spacer and a cushion is shown. The indicator button  14  is extended revealing the presence of a round having a cartridge bottom  36 . 
     Referring now to FIG. 6, a cut away side view of an example of the product detector of the invention deployed in an ammunition canister lacking spacers and cushions is shown. Note that, even in the absence of filler material and spacers, the probe  18  is constructed having a suitable length such that it contacts the cartridge bottom end  36 . The probe  18  is compressed enough to overcome the biasing effect of the probe spring so that the indicator cap  14  is extended to signal the presence of product. 
     Referring now to jointly to FIG.  7  and FIG. 8, a side view and a cut away side view respectively, of one example of another alternate embodiment of a product detector of the invention in a biased state is shown. A product detector  700  comprises a top  512 , a housing  503 , and a probe  518 . The probe  518  may advantageously be constructed as a cylinder having a pair of opposing grooves  72  therein (For simplicity, only one side is shown). The probe  518  is affixed at a top end  538  to housing  503  by conventional methods. The pair of grooves  72  are sized to be slidably engaged by a complementary pair of guide stakes  70  that prevent the probe  518  from rotating or dislodging. 
     Referring now again to FIG. 8, the alternate detector  700  includes a first biasing means  516  inserted into housing  503 . The first biasing means  516  may advantageously comprise a standard compression spring. An indicator pin assembly  555 , best shown in FIG. 9, is contained by housing  503 . The first biasing means  516  is held in place between the top  512  and an interior annular surface  523  of probe  518 . Retraction of probe  518  due to product contact thus causes the first biasing means  516  to compress, thereby allowing the second biasing means  526  to extend indicator button  525 . 
     Referring now to FIG. 9, a cross-sectional side view of one example of an indicator pin assembly  555  constructed in accordance with an alternate embodiment of the present invention is shown. The indicator pin assembly  555  preferably has a substantially circular cross-section. The indicator pin assembly  555  includes the probe  518 . The probe  518  is substantially cylindrical and has a top bore  517  at one end and a bottom bore  519  at a second, opposing end. The top bore  517  stops at surface  523  having an annular aperture  527  therein. The indicator pin  524  includes an integral indicator button  525 . The indicator button  525  includes a collar  551  at a proximal end and a flared end  552  at a distal end. The flare end  552  is sized to snap fit into the aperture  527  so that the distal end of the indicator pin is captured within the bottom bore  519  of the probe  518 . The indicator pin is also inserted through a second biasing means  526 , such as a standard compression spring, where the second biasing means is held between the collar  551  and the surface  523 . The first biasing means  516  is held in place between a second seal  514  and interior annular surface  523  of probe  518 . 
     The invention has been described herein in considerable detail in order to comply with the Patent Statutes and to provide those skilled in the art with the information needed to apply the novel principles of the present invention, and to construct and use such exemplary and specialized components as are required. However, it is to be understood that the invention may be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment details and operating procedures, may be accomplished without departing from the true spirit and scope of the present invention.