Abstract:
The present disclosure describes a capped syringe-like device for storing and dispensing liquid, with a movable plunger actuated by a rod inside a fluid dispensing container. The face sharing contact between the fluid dispensing container and the actuated plunger results in leak-proof dispensing of a controlled amount of liquid through a dispensing tip. The device may be used for refilling liquid containing vessels, for example.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority to U.S. Provisional Patent Application No. 62/049,102 entitled “WATERTIGHT LIQUID DISPENSER WITH SYRINGE-LIKE FUNCTIONS,” filed on Sep. 11, 2014, the entire contents of which are hereby incorporated by reference for all purposes. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present description generally relates to liquid dispensing systems and, in one example, to a portable, leak-proof device for controlled dispensing of liquids. 
       BACKGROUND AND SUMMARY 
       [0003]    Dispensing syringes and syringe-like devices may be used for storing, mixing, transporting, and dispensing a wide variety of liquids. These devices come in many forms and configurations, including assemblies comprising a barrel having a fluid discharge end, a plunger disposed within said barrel and having a threaded rod extending therefrom for engaging the plunger for advancement relative to the barrel, and a control portion for engaging said threaded rod. 
         [0004]    One example of the aforementioned type of dispenser is illustrated in Bergman, U.S. Pat. No. 4,144,988. The patent discloses a device with a piston and lead screw dispenser with a twistable projection. The device includes a dispenser spout at one end and is filled through the opposite end. In one embodiment, the tube and dispensing unit are made of plastic materials and the securement is by ultrasonic welding. When the dispenser tip is opened, rotating the lead screw projection will advance (determine the piston position) and discharge the tube&#39;s filling. 
         [0005]    Likewise, U.S. Pat. No. 1,447,712 by Darley discloses a dispensing device with a screw that operates the piston via turning the operating cap. The device is filled using the nozzle in the upper shaft and operated by unscrewing the conical cap and turning the operating clockwise motion. When a sufficient quantity of paste has been ejected, the operator then reverses the direction of the operating cap, moving the piston slightly towards the bottom and preventing the paste from leaking. 
         [0006]    The inventor herein has recognized problems with syringe-like dispensers of this kind, including issues related to their tendencies to leak, lack of portability, increased assembly complexity, and reduced ability to dispense small and accurate amounts of viscous liquids. 
         [0007]    As one example, Bergman&#39;s plunger assembly may be prone to leakage of liquids, as compared with more paste-like fillings. Similarly, leakage from the spout during transportation and non-dispensing conditions can be significant. Further still, simple manual assembly without addition tools, such as welders, is unachievable with the described configuration. Further still, the force necessary to rotate the base and generate accurate control of the amount of dispensed liquid can be either too high or too low depending on the degree of compression required to maintain a water-tight seal between the plunger and the wall. 
         [0008]    In one example, at least some of the above issues are addressed by a fluid dispensing device including a cylindrical housing including a dispensing tip, a movable plunger disposable in the cylindrical housing, the plunger including at least one protrusion configured to be in face-sharing contact with an inner surface of the cylindrical housing along an entirety of a dispensing path of the plunger, and a displacement element configured to at least partially extend into the dispensing tip. 
         [0009]    In this way, the cylindrical housing forms a liquid reservoir for containing a fluid. To dispense the fluid, the plunger is advanced via a suitable actuation mechanism, such as twisting of a twistable base coupled to the plunger. In an example, the plunger includes a silicone cap to form a watertight seal with the inner surface of the housing defining the liquid reservoir. Further, the displacement element may extend and project into an interior space of the dispensing tip of the housing to create an additional flow restriction for dispensing fluid, thus enabling precise control of small liquid amounts while also reducing waste liquid retained in the device at maximum plunger displacement. 
         [0010]    In another embodiment, the fluid dispensing device may comprise a housing body with a liquid reservoir and a slidable plunger rod with a plunger top that may be actuated into the housing body such that the plunger top acts as an displacement element and inserts into a dispensing tip of the housing body to dispense fluid from the device. A removable cap may be coupled to the housing body to plug the dispensing tip when fluid is not being dispensed. 
         [0011]    It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a perspective view of the external surfaces of a dispensing device according to an embodiment of the disclosure. 
           [0013]      FIG. 2  is a magnified cross-sectional view of the dispensing device of  FIG. 1 , with a plunger coupled to a central internal threaded rod in the fully extended position and a removable cap with its stationary plug protrusion fitted inside an aperture of the dispensing device. 
           [0014]      FIG. 3  is a magnified view of an end of the dispensing device of  FIGS. 1 and 2  with threaded rod in fully extended position at the second end. 
           [0015]      FIG. 4  is a cross-sectional view of the threaded rod of  FIGS. 1 and 2  rotated through the plunger and a twistable hand wheel that functions to actuate the rod. 
           [0016]      FIG. 5  is a cross sectional view of an additional embodiment of the dispensing device with a removable cap attached and the central threaded rod inserted inside a plunger which is situated at a first end of the housing body. 
           [0017]      FIG. 6A  shows a cross-sectional view of the device of  FIG. 5  with the threaded rod inserted into the plunger which is situated at a second end of the device. 
           [0018]      FIG. 6B  is a cross-section of the plunger cap with the threaded rod passing through its tubular core. 
           [0019]      FIG. 7A  is a schematic drawing of an embodiment of the housing body with a dispensing tip at its second end. 
           [0020]      FIG. 7B  is a schematic of the bottom of the first end of the housing body. 
           [0021]      FIG. 8  is a perspective view of the threaded rod having a singular helical thread and a base. 
           [0022]      FIG. 9  is a perspective view of the threaded rod inserted into a plunger and attached to a twistable handle. 
           [0023]      FIGS. 10A and 10B  are schematic drawings of the threaded rod attached to the twistable hand wheel. 
           [0024]      FIG. 11  shows an embodiment of the plunger base and plunger cap with a threaded rod passing through its core. 
           [0025]      FIG. 12  shows a perspective view of the plunger consisting of a base and a top. 
           [0026]      FIG. 13  is a schematic drawing of the cylindrical surface of the plunger. 
           [0027]      FIG. 14  is a schematic drawing of the planar surface of the plunger. 
           [0028]      FIG. 15  is a schematic of the bottom view of the plunger. 
           [0029]      FIG. 16A  is a perspective view of the removable cap. 
           [0030]      FIG. 16B  shows a schematic drawing of an embodiment of the removable cap. 
           [0031]      FIG. 17  is a perspective view of an embodiment of a dispensing device with a slidable plunger in a fully extended position when actuated in a housing body with a removable cap. 
           [0032]      FIG. 18  is a cross sectional view of the dispensing device of  FIG. 17 . 
           [0033]      FIG. 19  is a magnified cross sectional view of the dispensing end of the device of  FIG. 17  with the plunger fully extended. 
           [0034]      FIG. 20  shows a magnified view of an end of the housing body of dispensing device of  FIG. 17 . 
           [0035]      FIG. 21  shows a perspective view of the device of  FIG. 17 . 
           [0036]      FIG. 22  is a magnified cross sectional view of the device of  FIG. 17 . 
           [0037]      FIG. 23  shows an embodiment of the slidable plunger. 
           [0038]      FIG. 24A  shows an embodiment of the slidable plunger without the plunger top. 
           [0039]      FIG. 24B  is a cross sectional view of the plunger rod. 
           [0040]      FIG. 24C  is a cross sectional view of the plunger rod tip. 
       
    
    
     DETAILED DESCRIPTION 
       [0041]    The present application relates to a syringe-like device for easy and effective delivery and ejection of liquids, including viscous fluids such as oils, as well as water-based liquids or various other fluids. The dispensing system may include an outer tubular housing body and an inner liquid reservoir terminating in a dispenser tip having an aperture configured to expel liquid contained in the liquid reservoir. The dispensing system further includes a plunger comprising a silicone element that is receivable within the housing body and having an interior threaded portion. The silicone element is contiguous with a plastic base also having a threaded portion. A threaded rod is disposed within the inner liquid reservoir coaxial with the housing body and attached to a twistable hand wheel, which is configured to attach to the housing body at an end opposite the dispensing tip. The threaded portion of the plunger may be actuated along a length of the threaded rod by rotation of said hand wheel. A removable cap with a stationary plug protrusion located on the center of the inner surface of the cap fits into the aperture of the dispensing tip, serving as a physical plug to prevent liquid leakage when the cap is snapped onto the dispensing tip. 
         [0042]    In an example embodiment, the actuating plunger is comprised of a silicone plunger cap attached to a plastic plunger base wherein the silicone plunger cap defines a lower surface of the liquid reservoir and forms a tight seal between the liquid in the reservoir and the plunger. 
         [0043]    The centralized threaded rod actuating the axial movement of the plunger may be comprised of a continuous right-handed (or left-handed, if desired) external coarse thread, wherein the thread contains a pitch that is shorter relative to the depth of the thread. This produces a high depth to pitch ratio that enhances interactions and mechanics to enable the plunger silicone cap to move along the threaded rod with appropriate actuation force while forming a leak-proof seal against liquid in the liquid reservoir. Additionally, along with the sizing of the dispensing tip and the multiple restrictions formed by the threaded rod extending into the reservoir volume of the dispensing tip, the specific thread sizing enables precise control of small amounts of potentially highly valuable liquids. 
         [0044]    The liquid may exit the dispensing tip when the plunger is advanced through appropriate rotation of the threaded rod (e.g., clockwise) by the twistable hand wheel, wherein the threaded rod extends into the dispensing tip with the further advantage that the plunger may expel substantially all of the liquid in the liquid reservoir, minimizing residual liquid in the reservoir of the housing body. After near-complete expulsion of liquid, the twistable hand wheel can no longer be rotated due the plunger registering with an interfering angular protrusion that prevents further axial advancement. Furthermore, liquid may be drawn into the liquid reservoir by counter-clockwise rotation of the hand twistable portion. 
         [0045]    In one embodiment, the fluid dispensing device may comprise a housing body with a liquid reservoir, and a slidable plunger with a plunger top and a plunger base. The slidable plunger may be actuated into the housing body of the dispensing device, such that the plunger top inserts into the dispensing tip of the housing body to dispense fluid from the device. A removable cap may be attached to the dispensing device. 
         [0046]    In another embodiment, the housing body with a dispensing tip may have flat face sharing surface which interfaces with a complementary flat surface on a removable cap. The removable cap may have a plug in its inner wall which can plug the dispensing tip when the cap is attached to the housing body, thereby preventing liquid from leaking out and ensuring a secure fit between the housing body and the removable cap. The plunger top may have a complementary dispensing tip insert which inserts into the dispensing tip of the housing body and acts as a displacement element to expel fluid from the dispensing tip. 
         [0047]    In this way, a more discrete and compact package may be achieved. Further, in some examples, the assembly may be fully assembled with no welding or screwing necessary, and, therefore, the dispensing device can easily be constructed and utilized by individuals with little to no training. 
         [0048]    The embodiment illustrated in  FIGS. 1-16  is drawn approximately to scale, although various modifications in the relative sizing of one or more components may be made. 
         [0049]      FIG. 1  is a perspective drawing of a dispensing device  1 , with a removable cap  8  attached onto a tubular housing body  2 , which is adjoined to a twistable hand wheel  10 . The housing body  2  and the removable cap  8  may be constructed from a suitable polymer such as plastic, such that the outer surface  21  of device  1  is durable, smooth, hard, and lightweight. 
         [0050]      FIGS. 2-4  illustrate the dispensing device  1  in cross-section along its longitudinal axis (axis  54  in  FIG. 2 ). The dispensing device has a first, actuation end  50  and a second, dispensing end  52  opposite the first end  50 .  FIG. 3  shows a magnified view of the second end  52  while  FIG. 4  shows a magnified view of the first end  50 . 
         [0051]    The main body of dispensing device  1  comprises of the aforementioned tubular housing body  2  and an inner barrel serving as a liquid reservoir  3  having a bottom opening  11  for receiving a plunger  5  mounted on a threaded rod  4 . The second end  52  of the dispensing device  1  has a dispensing tip  6 . The tubular housing body  2  has a solid wall  26  with a thickness that extends uniformly to a spout area  27  where the wall thickness decreases temporarily before increasing again at the tip  6 . Further, the dispensing tip  6  has a discharge aperture  7  at its apex. The removable cap  8  is fitted around the dispensing tip  6  and a stationary plug protrusion  9  in the inner center of the removable cap  8  sits inside the aperture  7  to prevent fluid leakage. The housing body  2  has a concentric notch  13  on its outer surface which interlocks with a groove  14  on the inner wall of the removable cap  8 , securing a tight fit between the housing body  2  and the removable cap  8 . 
         [0052]    As explained above, the first end  50  has a bottom opening  11  for receiving the plunger  5 . For engagement of the threaded rod  4  in order to actuate the plunger  5 , the twistable hand wheel  10  may be rotated either clockwise or counterclockwise. 
         [0053]    The dispensing tip  6  is indented inward along the housing body&#39;s outer surface  21 , and forms a conical-shaped tip provided with a neck including the aperture  7 , wherein fluid is forcibly dispensed out of the aperture when plunger moves upward via the twistable hand wheel  10  being engaged and twisted. 
         [0054]    The twistable hand wheel  10  comprises a hollow cylindrical piece fabricated from plastic or similar material, with an outer hand grip portion  22  projecting away and out from housing body  2 , an indented inner piece  24  fitted tightly into the housing body  2  via insertion through the bottom opening  11 , and a circular chamber  18  or pocket wherein the threaded rod base  4   e  is securely inserted into to form a tight but reversibly contiguous attachment. 
         [0055]    The plunger  5  has a plunger base  5   a  and a plunger cap  5   b.  In one example, the plunger base  5   a  may be plastic while the plunger cap  5   b  may be made with a polymer material such as silicone, such that the plunger base  5   a  is more rigid than the cap  5   b.  The plunger cap  5   b  is contiguous to and physically bound to the plunger base  5   a  via a suitable fixing mechanism, such as glue, along one face of the plunger base  5   a.  The plunger cap  5   b  and the plunger base  5   a  both have a plurality of complementary, interlocking surfaces  15   a,    15   b,  each in face sharing contact with one another, that increase the surface area compared to a flat straight surface, and are able to be glued together to produce greater adhesion between the plunger base  5   a  and cap  5   b,  respectively. Further, the angled surfaces  25  of where the plunger base  5   a  and plunger cap  5   b  are in contact may be used to transfer forces/stresses generated during the rotation and movement of the plunger in a way to reduce forces tending to separate the two surfaces from one another, such as radial stresses and forces. 
         [0056]    The top of threaded rod  4  acts as a displacement element when the threaded rod  4  is closest to the second end  52  in a fully extended position (shown in  FIGS. 2 and 3 ). The top of the threaded rod  4  extends into reservoir space  23  near the dispensing tip  6  so that the top of the threaded rod  4  acts as an displacement element to expel substantially all of the liquid in the liquid reservoir, minimizing residual liquid in the reservoir  3  of the housing body. The second end  52  of the housing body  2  near the dispensing tip  6  has angular end stop protrusions  12  along its inner wall at a transition area before the conical dispensing tip  6  forms, forming the reservoir  23  between the protrusions  12  and the aperture  7 . When the plunger is moved to its fully extended position (e.g., the hand wheel is twisted and the plunger extends along the full length of the threaded rod), the rod  4  and plunger  5  interface with protrusion  12  with the rod threads  4   a  fully engaged along the entire inner (threaded) region of the plunger base  5   a  and cap  5   b.  After registering at the stop protrusions  12 , the plunger  5  can no longer advance along the threaded rod  4  via the rotation of the twistable hand wheel  10 . At its opposite end, the threaded rod  4  may have a cylindrical and smooth screw rod base  4   e  extending from the threaded rod  4 , wherein the rod base  4   e  is contiguous and reversibly attachable to the twistable hand wheel  10 . 
         [0057]    The plunger  5  includes a tubular channel  20  with a plurality of thread grooves, which may be formed as teeth, complementary to the rod thread  4   a,  and serve as a threaded bearing that engages the threaded rod  4 . The rod  4  is threaded continuously and uniformly through both cap  5   b  and base  5   a,  so that the rod  4  may be guided through the plunger  5  via said threaded bearing to form an interlaced and secure attachment. The face of the silicone plunger cap  5   b  opposite the face glued to the plunger base  5   a  is adjacent to and defines a bottom surface of the liquid reservoir  3  and forms a tight seal between the liquid in the reservoir  3  and the plunger  5 , so that no liquid may leak out. The cap  5   b  also forms a seal with the threads so liquid does not leak back through threads and out the bottom past the hand wheel (which may not be a water-tight seal). The surface of the outer circumference of the cylindrical plunger  5  (excluding the flat faces proximal and distal to the liquid reservoir  3 ) is contiguous to the inner wall of the housing body when it is stationary and/or being actuated along the threaded rod  4 . 
         [0058]    The device has a removable cap  8 , comprising a smooth plastic cylindrical covering that is uniformly thinner in the area that is physically in contact with and adjacent to the housing body  2  and uniformly thicker in the area adjacent to a hollow space  19  formed when the cap  8  is attached, and the conical-shaped stationary plug protrusion  9  located on the center of the inner surface of the cap  8 . When the removable cap  8  is snapped onto the housing body  2 , the plug protrusion  9  fits into the aperture  7  of the dispensing tip  6 , serving as a physical plug to prevent liquid leakage. The second end of the housing body  2 , near the dispensing tip  6 , includes a concentric notch  14  along its external surface, to which the removable cap  8 , having a complementary interlocking concentric groove  13 , can be snapped onto the housing body  2  to protect unwanted liquid expulsion from the aperture  7 . Device  1  is closed when the removable cap  8  is attached and open when the removable cap  8  is not attached. 
         [0059]      FIG. 5  shows the dispensing device with an alternate embodiment of a housing body  2 ′ and a removable cap  8 ′ attached to the dispensing end  52  of the dispensing device. Rather than having a tapered region from the outer surface of the housing body toward the dispensing tip, housing body  2 ′ includes a flat surface angled at 90° relative to the outer surface of the housing body, where the flat surface is coupled to a dispensing tip  6 ′ a dispensing aperture  7 ′. Additional elements of the dispensing device are similar as the embodiment described above with respect to  FIG. 2 , and thus the same reference numbers refer to the same parts. 
         [0060]    As shown in  FIG. 5 , the plunger is in a position situated closer to the twistable handle wheel  10  at the first end  50  of the device, away from the dispensing tip  6 ′ and the dispensing aperture  7 ′, thereby defining a first, larger volume of the liquid reservoir  3 . To prevent liquid from leaking out of the liquid reservoir, multiple interlocking surfaces may be created between the plunger base and the plunger cap and also between the plunger and the housing body  2 ′. In one such example shown in  FIGS. 5 and 6A , plurality of interlocking grooves and protrusions, securing a tight fit between the plunger base  5   a  and the plunger cap  5   b  are illustrated. For example, the plastic plunger base  5   a  may have a groove  56  which complementarily fits with a protrusion  55  on the plunger cap  5   b.  In other embodiments of the device, the angular disposition of the groove(s) and protrusion(s) may be of any desired orientation, as long as the contact sharing surfaces between them interlock securely. As the plunger moves along the longitudinal axis of the dispensing device  1 , a tight leak-proof fit between the plunger  5  and the inner wall of the housing body  2 ′ may be created by protrusions  57  and  58  of the plunger cap  5   b  which are in face-sharing contact with the inner surface of the housing to prevent fluid from leaking out from the fluid reservoir  3  and seeping in between the contact sharing surfaces of the plunger  5  and the housing body  2 ′. 
         [0061]    The removable cap  8 ′ includes a conical-shaped stationary plug protrusion  9 ′ located on the center of the inner surface of the cap  8 ′. When the removable cap  8 ′ is snapped onto the housing body  2 ′, the plug protrusion  9 ′ fits into the aperture  7 ′ of the dispensing tip  6 ′, serving as a physical plug to prevent liquid leakage. The second end of the housing body  2 ′, near the dispensing tip  6 ′, has a flat surface  92  interfacing with a complementary flat surface  91  on the removable cap  8 ′, ensuring a tight fit between the removable cap  8 ′ and the housing body  2 ′ to protect unwanted liquid expulsion from the aperture  7 . The dispensing device is closed when the removable cap  8 ′ is attached and open when the removable cap  8 ′ is not attached. 
         [0062]    When the dispensing device is open, rotation or twisting of the twistable hand wheel  10  in a clockwise direction will advance the plunger  5  along the threaded rod  4 . The plunger acts as a piston causing the liquid in the housing body that is contained between the plunger  5  and the dispensing tip  6  to be discharged, until movement of the plunger is stopped by angular protrusion  12 , at which point no more liquid may be dispensed. Rotating the twistable hand wheel  10  counterclockwise will cause the plunger  5  to retreat along the threaded rod  4  and create a suctioning effect wherein fluid or air near or in physical contact with the dispensing tip may be drawn into the liquid reservoir  3 . 
         [0063]    The apposition of plunger cap  5   b  with threaded rod  4  housed inside the cylindrical cavity is also shown in a cross section view  60  in  FIG. 6B , taken along section  6 B- 6 B of  FIG. 6A . 
         [0064]    An embodiment of the housing body  2  of the dispensing device  1  is illustrated in  FIGS. 5 ,  6 A,  7 A and  7 B, wherein the wall of the housing body  2 ′ has a flat surface  92 , perpendicular to the longitudinal axis of the device. The flat surface  92  is adjoining to the dispensing tip  6 ′ with the dispensing aperture  7 ′ for dispensing the liquid stored in liquid reservoir  3 . 
         [0065]    To secure a tight fit between the interlocking parts of the device, the housing body  2 ′ may have a plurality of threaded grooves to engage multiple parts of the dispensing device  1 . In one embodiment shown in  FIGS. 7A and 7B , concentric grooves  65 ′ at the distal base of the housing body  2 ′, contiguously and reversibly engage twistable hand wheel  10  to ensure tight interlocking fit.  FIG. 7A  shows the housing body in cross-section along the longitudinal axis, without the rod  4  or plunger  5  inserted into the housing body.  FIG. 7B  shows a view down the housing body  2 ′ from the first end towards the second end. 
         [0066]      FIG. 8-11  show the threaded rod  4  which may comprise a single right-handed external coarse screw rod thread  4   a  wound around a root  4   b  of the rod (e.g., central shaft of the rod). The thread  4   a  may include two diametrically opposed, helical flattened surfaces  4   c  that spirally extend along an axial length of said rod  4 . The thread of central threaded rod  4  has a pitch p defined as the longitudinal distance from the crest c on one ridge  4   d  to the crest c on an adjacent ridge  4   d  of the thread  4   a  and a depth d defined as the distance from the root of the rod  4   b  to a crest c, wherein the pitch may be shorter relative to the depth of the thread, as shown in  FIG. 8 . The high d to p ratio produces desired interactions and mechanics that enable the mounted silicone cap  5   b  of the plunger  5  to move along threaded rod  4  and form a leak-proof seal against liquid spillage from the liquid reservoir  3 . For example, the specific relative sizing, position, and ratios of lengths and widths can be particularly advantageous for engaging a plunger formed of two different materials having different sealing properties, and different stiffness so that sufficient structural rigidity is achieved while at the same time enabling smooth operation and water-tight seals to be achieved. 
         [0067]    A magnified schematic of the threaded rod inside the plunger shown in  FIG. 10 , illustrates that the threaded rod  4  may have a plurality of threads which may be of uniform width and may be angled in relation to the central longitudinal axis of the threaded rod  4 , allowing for movement of the plunger along the threaded rod when inserted in the housing body  2  or housing body  2 ′. The threaded rod  4  is affixed to the twistable hand wheel  10 . The rod  4 , hand wheel  10  and plunger  5  maybe inserted into the housing body as a unit. Turning the hand wheel in clockwise direction will move the plunger  5  on the threaded rod  4  towards the second end  52  of the device and turning the hand wheel  10  anticlockwise will move them towards the first end  50  of the device, thereby decreasing or increasing the volume of the liquid reservoir  3 . 
         [0068]    In order to enhance hand grip to maximize ease of twisting motion, the twistable hand wheel  10  may be comprised of a plurality of linear parallel ridges on the hand grip portion  22 , each extending parallel along the body of the twistable hand wheel  10 . At the junction of the threaded rod  4  and the twistable hand wheel  10 , there may be a step protrusion  66  which in apposition with the concentric grooves  65  on the housing body  2  (or with the concentric grooves  65 ′ on the housing body  2 ′) can regulate the range of movement of the twistable hand wheel  10  into the housing body  2 . A magnified view of the step protrusion is shown in  FIG. 10 . 
         [0069]    In another example, an O-ring may be used to create a seal between the bottom of the plunger base  5   a,  (face not glued to the cap  5   b ) and the twistable hand wheel  10 , wherein the O-ring may be placed in a concentric groove along the inner wall of the housing body  2  or housing body  2 ′, sitting adjacent and contiguous to the twistable hand wheel  10 . In another example, a seal may be formed without the use of an O-ring. The twistable hand wheel  10  is adjoined to housing body  2  by a small concentric groove  17  that is located along the internal circumference of the housing body  2  at the opening of the first end (shown in  FIGS. 2 and 4 ), wherein the twistable hand wheel  10  may be snapped into via a small complementary concentric notch  16  along its external circumference, so that the outer surface of the indented inner piece  24  is attached contiguously to the inner surface of the housing body  2 . 
         [0070]    In one embodiment to assemble the device, the plunger  5  (plastic plunger base  5   a  and silicone plunger cap  5   b  glued together) is coupled to (e.g., twisted) onto the threaded rod  4 , so that the bottom edge of the plastic plunger base  5   a  (e.g., the surface opposite the surface coupled to the silicone cap  5   b ) is flush with the base edge of the threaded rod base  4   e,  so as to maximize the volume of liquid able to be filled into the housing body  2 . The combined plunger  5  and threaded rod  4  assembly is then inserted into the housing body  2 , with the plunger  5  and threaded rod base end  4   e  located at the first end of the housing body  2  and the top end of the threaded rod located at the second, dispensing tip  6  end of the device. The twistable hand wheel  10  is then snapped into the distal end of the device  1 , wherein the threaded rod base  4   e  fits (e.g., press-fit) into the hollow chamber  18  of the twistable hand wheel  10  so that they rotate together and are affixed to one another. Alternatively, the twistable hand wheel  10 , plunger  5  and threaded rod  4  may be assembled together and then inserted into liquid housing body  2 . 
         [0071]    In one example, no welding of any kind is required to assemble the dispensing device  1  which maximizes ease and simplicity in assembling, disassembling and cleaning. However, welding may be used, if desired. 
         [0072]    In practice, the device can sit flat onto a bottom surface of the twistable hand wheel  10  and liquid can then be delivered by a compatible vertically-dispensing device into the liquid reservoir  3  via entry through the aperture  7  of the dispensing tip  6 . After filling, the device  1  can be secured for transport by snapping on the removable cap  8 . 
         [0073]    In an embodiment of the plunger illustrated in  FIGS. 12-15 , the plunger base  5   a  and plunger cap  5   b  may each have a planar surface  68  and a remaining cylindrical surface  69 . Angular protrusions  58  and  57  are radially arranged around the circumference of the plunger cap  5   a  which secure a tight fit between the contact sharing surface of the housing body  2  and the plunger cap  5   b,  to prevent liquid leakage. For example, the protrusions may be in face-sharing contact with an inner surface of the cylindrical housing along an entirety of a dispensing path of the plunger, where the dispensing path of the plunger comprises the range of positions the plunger is configured to travel while disposed in the dispensing device.  FIG. 15  shows a schematic view of the tubular channel  20  present in the core of the plunger  5  for housing the threaded rod  4 . 
         [0074]    An embodiment of the removable cap is shown in  FIGS. 16A and 16B , where the removable cap  8 ′ has a flat surface interfacing with surfaces on the housing body  2 ′. For example, the flat surface  91  on the removable cap  8 ′ is in apposition with the flat surface  92  on the housing body  2 ′. 
         [0075]    In another embodiment, a fluid dispensing device with a housing body and a removable cap may be coupled with a slidable plunger to dispense fluid from the device.  FIGS. 17-24C  illustrate an embodiment of a syringe like liquid dispensing device  100  with a slidable plunger and a removable cap.  FIGS. 17-24C  are drawn approximately to scale.  FIGS. 17 and 18  show the liquid dispensing device  100  with a first, actuation end  101  and a second, dispensing end  102 , opposite the first end  101 . The dispensing device  100  comprises of a tubular housing body  104  with a liquid reservoir  117 , a slidable plunger  110 , and a removable cap  116 . The removable cap  116  is similar in shape and configuration to the removable cap  8 ′ described above. However, in some embodiments, the removable cap  116  may be similar in shape and configuration to removable cap  8 , and thus the housing body  104  may include similar corresponding features to the housing body  2  of  FIG. 2 . The housing body  104  has a bottom opening  108  for accommodating the slidable plunger  110 . The slidable plunger  110  includes a plunger rod  111 , a removable plunger top  120 , and a plunger base  122 . The second end  102  of the dispensing device  100  has a removable cap  116 . 
         [0076]    The plunger  110  inserts into the bottom opening  108  of the tubular housing  104 , such that the removable plunger top  120  inserts first, oriented towards the dispensing second end  102  of the housing body  104  and the plunger base  122  is at the actuation end  101 . The removable plunger top  120  may have a plurality of annular grooves and ridges  124 , to secure the plunger inside the housing body and to prevent fluid leakage. The plunger rod  111  may have a plurality of longitudinal ridges  113  along its longitudinal axis  99 . The plunger rod may also have plurality of radially arranged tab protrusions  115   a  and  115   b  to provide structural rigidity and support to the plunger rod  111  during the sliding action of the plunger  110  into the housing body  104 . The plunger base  122  extends out of the housing body  104  when the slidable plunger  110  is completely engaged in the housing body  104  (shown in  FIGS. 17 and 18 ). The plunger base  122  defines a finger engagement surface for operating the dispensing device  100 . The outer circumference of the housing body  104  has a flange  132  situated at the actuation end  101  for providing user grip while operating the device  100 . 
         [0077]    The plunger rod  111  inserts into the plunger top  120  and secure interlocking is established by surface to surface contact of complementary surfaces. A plurality of complementary groove(s) and protrusion(s) between the contacting surfaces of the plunger rod  111  and the plunger top  120  secure the plunger rod and plunger top together and prevent liquid from leaking through the adjoining surfaces. As shown in  FIGS. 18 and 19 , groove  142  on the plunger top  120  may have a complementary fit with protrusion  140  on the plunger rod  111 . As the plunger moves along the longitudinal axis  99  of the dispensing device  100 , a tight leak-proof fit between the plunger rod  110  and the plunger top  120  is created by protrusions  140  and groove  142  which are in face-sharing contact, thus preventing liquid from leaking out from the fluid reservoir  117 . For example, one or more of protrusions  140  may be in face-sharing contact with an inner surface of the cylindrical housing along an entirety of a dispensing path of the plunger. Protrusion  146  on the plunger rod  111  is also in apposition with the plunger top  120 , ensuring a secure fit. The angular disposition of the groove(s) and protrusion(s) may be of any desired orientation, as long as the contact sharing surfaces between the respective grooves and protrusions interlock securely. A plunger rod tip  170  interfaces with the plunger top  120  to secure a tight fit between the plunger rod and the plunger top, as shown in  FIG. 19 . 
         [0078]    A plurality of grooves and ridges  124  on the plunger top  120  interface with the housing body  104  inner wall to ensure a secure, leak-proof fit of the plunger top  120  inside the housing body  104 . The interlocking of the grooves and ridges  124  with the housing body inner wall ensure that no liquid leaks from the liquid reservoir  117  past the plunger top when the plunger  110  is slidebaly actuated through the housing body  104  towards the dispensing end second position  120 . 
         [0079]      FIGS. 18-20  show the housing body  104  with a dispensing tip  127  and a dispensing aperture  129  at the dispensing end  102 . The dispensing tip  127  has an aperture  129 , wherein fluid is forcibly dispensed out of the aperture when plunger  110  slides inside the housing body  104 , towards the second end  102 , and is in a fully extended position. A dispensing tip insert  126  on the plunger top  120  acts as a displacement element which inserts into the dispensing tip  127  of the housing body, forcing maximum possible volume of fluid out of the dispensing aperture  129 . 
         [0080]    A magnified cross sectional view of the dispensing end  102  of the device  100  with the removable cap  116  attached is shown in  FIG. 19 . When the removable cap  116  is attached on the second end of the device, a dispensing aperture plug  133 , present on the inner surface of the removable cap  116 , inserts into the dispensing aperture  129  and serves as a physical plug to prevent liquid leakage. The second end  102  of the housing body  104  has a flat interfacing surface  91 , adjoining the dispensing tip  204 . When the removable cap  116  is attached to the housing body  104 , the flat surface  91  on the removable cap  116  interfaces with the flat surface  92  on the housing body  104 . 
         [0081]      FIGS. 21 and 22  show the device  100  with the plunger top  120  inserted in opening  108  of the housing body  104  and positioned in the proximity of the first actuation end  101  of the device, such that the volume of a liquid reservoir  117  is at its maximum. 
         [0082]      FIG. 23  shows an isolated view of the sliding plunger  110  with the plunger base  122 , the plunger rod  111  and the removable plunger top  120 . A schematic of the plunger  110  without the plunger top  120  is shown in  FIG. 24A . The plurality of longitudinal ridges  113  along with the radially arranged tabs  115   a  and  115   b  on the plunger rod  111  provide structural rigidity to the slideable plunger when actuated into the housing body  104  of the liquid dispensing device  100 . The plunger rod  111  is coupled to a plunger rod tip  170 . Protrusions  142  and  146  interface with the removable plunger top  120  to secure the plunger rod  111  and the plunger top  120 . 
         [0083]      FIG. 24B  shows a cross sectional view of the plunger rod  111  taken along section  24 B- 24 B of  FIG. 24A . The arrangement of longitudinal ridges  113  ( 113   a,    113   b,    113   c,    113   d ) is shown in the schematic. 
         [0084]    The plunger rod top  170  inserts into the removable plunger top  120  (as shown in  FIG. 19 ). A cross sectional view of the plunger rod top  170  taken along section  24 C- 24 C of  FIG. 24A  is shown in  FIG. 24C . A plurality of radially arranged tabs  171  are shown. The tabs  171  secure a tight fit between the plunger rod top  170  and the plunger top  120 . The tabs  171  originate from a common central point hub  172 . 
         [0085]    It is understood that the dispensing device described and illustrated herein represents only an example embodiment. It is appreciated by those skilled in the art that various changes and additions can be made to such dispensing devices without departing from the spirit and scope of this invention. In one example, the dispensing device may include a threaded rod having a different pitch to depth ratio than described (e.g. larger pitch than depth), having differently spaced/sized threads along the length of the threaded rod, having a left-handed thread, etc. Furthermore, although the dispensing device has been described herein as having a silicone plunger cap, another material (e.g. polymer, elastomer or composition) can be fabricated as the plunger cap instead of silicone that is more flexible than the plunger base. 
         [0086]    An example of a dispensing device may comprise a cylindrical housing including a dispensing tip, a movable plunger disposable in the cylindrical housing, the plunger including at least one protrusion configured to be in face-sharing contact with an inner surface of the cylindrical housing along an entirety of dispensing path of the plunger, and a displacement element configured to at least partially extend into the dispensing tip. The displacement element may be positioned on the plunger and may be configured to extend into the dispensing tip when the plunger is in a fully extended position. In one example the plunger may couple with a slidable rod such that the tip of the plunger acts as a displacement element. In another embodiment, the plunger may be coupled to a threaded rod wherein the tip of the threaded rod acts as a displacement element ejecting fluid from the dispensing device. 
         [0087]    In one embodiment, an assembly is provided comprising a cylindrical housing holding a plunger therein movable via a twistable base coupled to an internal threaded rod, the twistable base snap fit with the housing, the plunger comprising at least two sections adjacent one another and each engaging threads of the rod, a first portion of the plunger more flexible than a second portion. In yet another embodiment, an assembly is provided comprising a cylindrical housing holding a plunger therein movable via a twistable base coupled to an internal threaded rod, the threaded rod extending into a constricting volume defined by a dispensing tip. 
         [0088]    In one embodiment, an assembly is provided comprising a cylindrical housing holding a plunger movable therein and having an internal threaded rod, the rod threads having a larger depth than pitch. 
         [0089]    An embodiment for a fluid dispensing device is provided. The fluid dispensing device comprises a cylindrical housing and a movable plunger disposable in the cylindrical housing and a movable rod coupled to the plunger, configured to extend into a dispensing tip of the cylindrical housing. In one example, the plunger comprises a base coupled to a cap, each of the base and cap configured to engage threads of the threaded rod. The cap of the plunger may be more flexible than the base of the plunger. In one example, the cap is coupled to the base via an adhesive material. In another example, the cap is coupled to the base via interlocking complementary contact sharing surfaces. The threaded rod may comprise threads having a larger depth than pitch. The device further includes a removable cap that plugs the dispensing tip when attached to the dispensing tip of the cylindrical housing. The removable cap may be secured to the cylindrical housing body by interlocking grooves and intercepting protrusions between contact sharing surfaces of the removable cap and cylindrical housing body. 
         [0090]    An embodiment for a dispensing device comprises a housing having a first, open end and a second, dispensing end, the second end including a dispensing tip with an aperture; a plunger assembly comprising a base coupled to a cap; a threaded rod; and a hand wheel coupled to the threaded rod, the plunger assembly and threaded rod configured to be inserted into the housing via the open end such that the threaded rod extends into the dispensing end. 
         [0091]    Another embodiment for a dispensing device comprises a housing having a first, open end and a second, dispensing end, the second end including a dispensing tip with an aperture, a plunger assembly comprising a plunger coupled to a rod, the plunger including a body and a radial protrusion extending outward from the body, the radial protrusion configured to be in face-sharing contact with an inner surface of the housing, the plunger assembly further including a displacement element configured to extend into the dispensing tip in at least one position of the plunger assembly; and a base. In one example the rod coupled to the plunger may be a slidable rod, wherein the base is a finger engaging surface for actuation of the slidable rod. In another embodiment, the plunger may be coupled to a threaded rod, and wherein the base is a twistable hand wheel coupled to the threaded rod. The plunger assembly may comprise of a hollow chamber such that a surface of each hollow chamber is configured to engage with the rod inserted into the hollow chamber. 
         [0092]    The plunger may comprise a radial protrusion configured to be in face-sharing contact with an inner surface of the housing. The threaded rod may comprise a cylinder and an external thread wound in a spiral along a length of the cylinder, the cylinder extending beyond a terminal end of the external thread and into the dispensing tip. The external thread may have a pitch that is smaller than a depth of the thread. 
         [0093]    In an example, the base and the cap of the plunger assembly each comprise a hollow chamber, a surface of each hollow chamber including an internal thread configured to engage with the external thread of the threaded road when the threaded rod is inserted into the hollow chamber. The dispensing device further comprises a removable cap configured to block the aperture when the removable cap is coupled to the housing. 
         [0094]    A further embodiment of a dispensing device comprises a hollow cylindrical housing having a first end and a second end, the second end including a dispensing tip with an aperture, a plunger actuation assembly coupled to the housing and comprising a plunger with a hollow chamber coupled to a rod, the rod coupled to a base, and a removable cap configured to couple to the dispensing tip of the housing. In one example, the rod comprises a dispensing end and a rod portion intermediate the base and the dispensing end, the base positioned outside the housing body, the dispensing end extending into the dispensing tip of the housing. In one example the plunger, rod, and base are coupled together via a snap-fit mechanism. In another example the plunger actuation assembly is coupled to the housing via a snap-fit mechanism. In one embodiment, the plunger is at least partly comprised of silicon. 
         [0095]    A further embodiment of a dispensing device comprises a hollow cylindrical housing having a first end and a second end, the second end including a dispensing tip with an aperture; a plunger actuation assembly coupled to the housing, and a removable cap configured to couple to the dispensing tip of the housing. The plunger assembly comprises a plunger including a base coupled to a cap and having a hollow chamber with an internal thread; a threaded rod disposed within the hollow chamber and comprising a cylinder and an external thread wound around the cylinder to engage with the internal thread of the plunger; and a hand wheel coupled to the threaded rod. The cylinder of the threaded rod comprises a base end, a dispensing end, and a threaded portion intermediate the base end and the dispensing end, the base end positioned in a pocket of the hand wheel, the dispensing end extending into the dispensing tip of the housing, wherein the external thread is wound around the threaded portion. In an example, the plunger, threaded rod, and hand wheel are coupled together via a snap-fit mechanism. In an example, the plunger actuation assembly is coupled to the housing via a snap-fit mechanism. The cap of the plunger may include an outer cylindrical surface with a planar face and a radial protrusion in face-sharing contact with an inner surface of the housing. The cap of the plunger may be comprised of silicon and the base of the plunger may be comprised of plastic. 
         [0096]    In an embodiment, a method for dispensing fluid from a liquid reservoir comprise advancing a plunger along a threaded rod disposed in a liquid reservoir towards a dispensing tip of the reservoir, and dispensing liquid from the dispensing tip. In one example, the method comprises twisting a hand wheel coupled to the threaded rod in a first direction to advance the plunger. In an example, the method comprises twisting the hand wheel in a second direction opposite the first direction to move the plunger away from the dispensing tip. In another embodiment, a slidable plunger with a rod may be actuated into the housing body of the device by an actuating base coupled to the rod to dispense fluid from the dispensing tip of the dispensing device. 
         [0097]    In another embodiment, a sliding plunger rod coupled to a plunger top may be actuated along the housing body with a dispensing tip. The plunger top has a tip insert which inserts into the dispensing tip and acts as a displacement element to remove fluid from the dispensing tip. In another example, a removable cap may be attached to the housing body and secured by flat complementary face sharing surfaces present on the housing body and on the interfacing surface of the removable cap. The removable cap may plug the aperture of the dispensing tip when attached to the device. 
         [0098]    As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising,” “including,” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property. The terms “including” and “in which” are used as the plain-language equivalents of the respective terms “comprising” and “wherein.” Moreover, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements or a particular positional order on their objects. 
         [0099]    This written description uses examples to disclose the invention, including the best mode, and also to enable a person of ordinary skill in the relevant art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.