Abstract:
A utility knife is useful for operations such as glazing, roofing, carpeting and sheet rock fabrication wherein the knife is used in close proximity to window edges, walls or corners. A blade-holding portion of the utility knife has a planar bottom wall and structure for mounting the blade at a small angle relative to the bottom wall so that the blade is able to flex and substantially conform to the plane of a surface upon which the planar bottom surface of the utility knife is supported. A handle portion of the utility knife is offset from the planar bottom surface so as to position a user&#39;s hand away from the surface on which the utility knife is supported.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of application Ser. No. 11/352,728 filed Feb. 13, 2006, now U.S. Pat. No. ______, which is a continuation-in-part of application Ser. No. 10/822,240, filed Apr. 9, 2004, now abandoned, both of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    Various prior art utility knives place the knife blade in-line with the handle and minimize protrusion of the knife to reduce blade breakage. Any angulation suggested is within the plane formed by the handle and the plane of the knife. This arrangement of the knife components fails to solve a troublesome problem encountered by glaziers and sheet rock workers, namely the need to make perpendicular cuts in tight corners. Such cuts require long blade lengths and close placement of a worker&#39;s hand in tight corners increasing the risk of injury. An in-line placement of blade and handle prevents a close approach of the knife to the wall edge or base due to the size of the worker&#39;s hand and in-line location of the blade. 
       SUMMARY 
       [0003]    Disclosed embodiments provide a utility knife having a transverse angulation feature that enables carpet cutting, glue scraping, roof work, glazing and sheet rock operations to proceed in a safe, efficient and reliable manner. A blade-holding portion of the utility knife has a planar bottom wall and structure for mounting the blade at a small angle relative to the bottom wall so that the blade is able to flex and substantially conform to the plane of a surface upon which the planar bottom surface of the utility knife is supported. A handle portion of the utility knife is offset from the planar bottom surface so as to position a user&#39;s hand away from the surface on which the utility knife is supported. In certain embodiments, a utility knife has a multi-edged blade and a two-piece construction comprising a bottom section and a top section. A reversible multi-edged detachable blade with an anchoring hole may be mounted on a locating lug attached firmly to the bottom section or top section. The locating lug locates the blade and prevents forward or reverse motion. The blade is held firmly between the bottom and top sections within a channel by clamping the sections together and fixing them in the clamped condition using a toe-in-shoe attachment at the blade end of the handle and a fastening means, such as a machine screw, a countersunk hole and threaded tap-hole at location on the handle displaced from the toe-in-shoe attachment. The clamping section of the handle locates the blade firmly at a slight angle between about 2° and 10°, preferably at about 5°, to the horizontal plane defined by the planar bottom surface of the bottom section. As use herein, a “planar bottom surface” need not be a continuous flat surface and may contain channels, concavities and the like, so long as it provides a support surface for the utility knife that aligns the knife with a planar surface upon which it is used. 
         [0004]    In one embodiment, the channel in the bottom section firmly captures the multi-edged blade between edges of the channel and locates the blade in the desired plane. The channel is angled at a slight angle between about 2° and 10°, preferably at about 5°, from a horizontal plane defined by a planar bottom surface of the bottom section. This rigid attachment grips the blade firmly (by the compression caused by machine screw or screws in combination with the toe-in-shoe attachment) within the channel located by the locating pin and allows longer protrusion of the blade to allow desirable flexing of the blade to meet the needs of glaziers, roofing contractors, carpet installers and sheet rock workers. The bottom section may include a hollow portion providing a storage compartment in the bottom section for holding one or more blades. 
         [0005]    Each of the blades may have symmetrical geometrical structures with two or more cutting edges, and preferably at least four cutting edges and two or more sharp corners. The multi-edged blade may be reversible end-to-end and side-to-side to provide a fresh cutting edge. The multi-sided blade may be replaced with a new blade from the optional storage compartment within the bottom section of the handle. If the utility knife is exclusively used for left-handed or right-handed use, the blade may be turned upside down to provide a fresh unused sharp edge. The blade may have two holes, which match with the locating pin. The multi-edge blade is suited for use as a utility knife for left-handed or right-handed cutting without any blade adjustment. 
         [0006]    As a consequence of the transverse angulation of its blade and offset handle, the utility knife is especially convenient for use in window glazing applications, roof cutting or carpet cutting, since the hand is not located in-line with the blade. The transverse angulation of the blade may be in the range of about 2° to 10° and preferably about 5°. The offset handle may also be transversly angulated in the range of about 100 to 170 and more preferably between about 135° to 150°. The knife may not be angled for making cuts in tight corners and cuts, which is essentially perpendicular to the surface can be easily made since the size of the hand is accommodated by the offset and/or transverse angulation of the handle. The utility knife can be used in right angle applications such as scoring of linoleum or sheet rock in tight places, such as corners and the like. Previous utility knives have been stubby and straight. These prior art configurations prevented facile operation of the knife, owing, in part, to interference from the operator&#39;s hands. 
         [0007]    The various disclosed embodiments of a multi-edged utility knife are designed to address a common system for window glazing that comprises use of a frame having a right-angled open channel to accommodate a glass pane. The glazing may be accomplished by placing a bed of putty or similar glazing compound along the inside vertex of the channel and then inserting a pane of glass into the bedding compound. The pane is pressed to extrude any excess putty and assure complete coverage of the edge and a fully hermetic seal. The pane may then be secured with glazing points or similar fasteners. 
         [0008]    This system is intended to allow replacement of broken glass in a simple manner. However, extraction of the old pane frequently requires use of a sharp knife or similar flat cutting instrument to break the putty seal between the flat surface of the glass near its edges and the sides of the right-angled frame generally parallel thereto, requiring a perpendicular cut. Conventional straight utility knifes, putty knives, or razor blades are often used for this task but have proven to be poorly suited and, in some cases, even hazardous to the artisan. With each of these tools, the user&#39;s hand gripping the handle prevents the blade from being aligned with the perpendicular plane of the gap between the window and the frame. The user may attempt by downward pressure against the glass to bend the blade to align and insert it in the gap for cutting. However, the bending and pressure entail significant risk of injury, as the generally brittle blade may snap and project sharp fragments or the glass may fracture and expose the user&#39;s hand to laceration. In marked contrast, the transverse angulation of the present blade and offset handle that provides a stable knife support obviates these difficulties. Inadvertent breakage of blades is reduced or eliminated. Disclosed embodiments of the utility knife allows making cuts, which are essentially perpendicular to the surface easily, a feature unavailable in knifes where the handle is in-line with the knife blade. The force applied by the user against the glass is significantly lower than that heretofore required to bend the blade of prior art glazing knives. This, in turn, greatly reduces the risk of injury to the artisan from broken glass or blades. Disclosed embodiments of the utility knife are also far less likely to nick or otherwise damage the window frame. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1   a  illustrates a side sectional view of a multi-edged utility knife at  10 , which accepts a variety of multi-edged blades suited for various applications including carpet installers, roofers and glaziers in the as supplied condition, showing the front view and top view of the transversely angulated knife; 
           [0010]      FIG. 1   b  illustrates a top view of multi-edged utility knife of  FIG. 1   a;    
           [0011]      FIG. 2   a  illustrates a side view of the details of bottom section  14 ; 
           [0012]      FIG. 2   b  illustrates a top view of the details of bottom section  14  of  FIG. 2   a;    
           [0013]      FIG. 3   a  illustrates a side view of the details of the top section  12 ; 
           [0014]      FIG. 3   b  illustrates a top view of the details of top section  12  of  FIG. 3   a;    
           [0015]      FIG. 4  illustrates a corner utility blade knife element  16  in a configuration as a wallboard blade; 
           [0016]      FIG. 5  illustrates a corner utility blade knife element  16  in a configuration as a combination carpet/scraper blade; 
           [0017]      FIG. 6  illustrates a corner utility blade knife element  16  for a roofing blade configuration; 
           [0018]      FIG. 7  illustrates a corner utility blade knife element  16  for a glazier blade configuration; 
           [0019]      FIG. 8   a  illustrates a side view of an alternate embodiment of an angulated utility knife; 
           [0020]      FIG. 8   b  illustrates a side view of a blade-supporting portion with a blade flexing to be substantially parallel to a supporting surface; 
           [0021]      FIG. 8C  illustrates a side view of a bottom portion of the utility knife handle; 
           [0022]      FIG. 8D  illustrates a side view of a top portion of the utility knife handle; 
           [0023]      FIG. 9   a  illustrates a side sectional view of a blade supporting portion with a retractable blade carriage; and 
           [0024]      FIG. 9   b  illustrates a top view of a blade supporting portion with a retractable blade carriage. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    As used herein, the term “multi-edged blade” refers to a thin, flat blade formed of suitably strong metal or the like that has between 2 and 6 edges that have been sharpened for cutting purposes. The term “multi-edged utility knife” refers to disclosed embodiments of a utility knife that is capable of making perpendicular cuts to surfaces which are in close proximity that would ordinarily prevent conventional in-line knifes being used due to their stubby construction as well as inability of hand which grips the handle to approach the region to be cut with the blade in a vertical position. The multi-edged utility knife also has the ability to expose a fresh unused edge by reversing the blade side-to-side or left-to-right or use a new blade from the holding compartment. Since the multi-edged knife blade is omnidextrous it may be used conveniently for left-handed or right-handed use. The multi-edged blades preferably have two holes which mate with a locating pin or lug when the blade is rotated by 180 degrees. In a preferred embodiment, the multi-edged utility knife has top and bottom sections which holds the blade in a clamping section including a locating pin or lug on the top or bottom section. The two sections are securely held together using one or two machine screws on one end and a toe-in-shoe attachment at the other end of the utility knife. The knife blade sits in a channel formed in the blade-holding portion of the bottom section so that it does not move. The blade is entirely locked in position within the blade-holding portion and its position is not maintained by friction. The term “transversely angulated” means that the knife blade is nominally angled slightly with respect to a bottom surface of the knife. The handle portion of the utility knife can also be transversely angulated or offset relative to the bottom surface of the utility knife to provide clearance for a user&#39;s hand. 
         [0026]    Referring to  FIG. 1   a  there is shown a side sectional view and directly below it in  FIG. 1   b  a top sectional view of an embodiment of a utility knife for wallboard use in  10 . It shows an extended knife blade element at  16 , where it protrudes less than 50% of its length and is held by the top section  12  and the bottom section  14 . The top section  12  is shown as a transparent body in  FIG. 1   b  to illustrate the details of placement of the multi-edged wallboard blade  16 . The knife blade element  16  is held tightly between the top and bottom sections  12  and  14  by the clamping force of a bolt  20  that passes through top section  12  and is threaded into a hole at  27  in the bottom section  14 . The clamping method may be other than use of a bolt as indicated in the drawing. One of the holes in the knife blade element  16  mates with a pin or lug protrusion  18  in the bottom section  14 , and the knife blade element rests in a channel  17  in the bottom section  14 . Alternatively, the pin may be attached to the top section or may be located in holes drilled in the top and bottom sections. Although not shown at an angle, the channel  17  and blade clamping surface  13  are angled at a slight angle between about 2° and 10°, preferably at about 5°, from a horizontal plane defined by a planar bottom surface  15  of the bottom section  14 . The tip  24  at the end of blade clamping surface  13  on the left side member  12  slides inside a shoe like protrusion in the right side member at  23  so as to hold blade  16  in a lower, off-center position angled slightly with respect to the planar bottom surface  15 . The knife blade is easily removed by loosening the bolts  20 , and separating the top and bottom sections  12  and  14 . The bottom section  14  preferably has a cavity at  19  to hold extra knife blades  22 . Since the multi-edged blade element  16  is symmetrical, it may be used in a left-handed or right-handed configuration without any modification to the multi-edged blade. 
         [0027]    Structural details of an embodiment of a multi-edged utility knife are shown in  FIGS. 2   a ,  2   b ,  3   a  and  3   b . In  FIG. 2   a  there is shown a side view detailing bottom section  14 . Directly below, in  FIG. 2   b , a top view of the bottom section  14  is depicted. A channel  17  is formed adjacent planar bottom surface  15  in the blade-supporting portion to accept the knife blade. The width of the channel is substantially the same as the width of the blade, which is designed to fit as a loose fit. The depth of the channel  17  combines with the clamping surface  13  to form a space that is slightly less than that of the blade thickness so that when the top and bottom sections  12  and  14  are clamped, the knife blade  16  is firmly held. Also illustrated is an opening which houses spare knife blades at  19 . The bottom section carries the locating pin or lug protrusion  18  within the channel  17 , as shown to receive the hole in a blade element. It has a threaded hole at  27  to accept the bolt  20 , which accomplishes the clamping action of the top and bottom sections. Bottom section  14  has a shoe-like protrusion at  23  to accept the tip  24  of the top section. The threaded portion of the bolt is only as deep as that of the bottom section and the bolt fits as a sliding fit into the top section. Thus, the shoe  23  and tip  24  firmly hold the knife blade element in between the top and bottom sections even when force is applied to the knife blade. 
         [0028]      FIG. 3   a  illustrates the details of the side view of top section  12  and its top view is shown in  FIG. 3   b . The tip  24  of clamping surface  13  on top section  12  is designed to slide into shoe  23  of the bottom section and capture the knife blade element  16 . The hole at  28  is a clearance hole for the bolt  20 . 
         [0029]    Referring to  FIG. 4 , the detail of the multi-edged knife blade element  16  of  FIG. 1  configured as a wallboard blade is shown at  40 . The multi-edged wallboard blade has two sharp edges at  42  and two locating holes at  44 . The multi-edge wallboard blade has four sharp corners suited for scoring wallboards at  43 . This multi-edged wallboard blade may be used in the forward direction or reversed direction for left-handed or right-handed operation. 
         [0030]    Referring to  FIG. 5 , there is shown further structural details concerning the multi-edged knife blade element  16  of  FIG. 1 . As illustrated by  FIG. 5 , the multi-edged knife blade is configured as a combination carpet/scraper blade, shown generally at  50 . The multi-edged carpet/scraper blade has a sharp edges at  52  and two locating holes at  54 . The multi-edge carpet/scraper blade has four sharp corners suited for scoring carpets at  55 . The sharp edge at  53  is used for scraping carpet glue. This multi-edged carpet/scraper blade may be used in the forward direction or reversed direction for left-handed or right-handed use. 
         [0031]    Referring to  FIG. 6 , the detail of the multi-edged knife blade element  16  of  FIG. 1  configured as a roofing blade is shown at  60 . The multi-edged roofing blade has sharp hook like corners  63 , with sharp cutting edges  62  and two locating holes  64 . This multi-edged roofing blade may be used in the forward direction only for left-handed or right-handed operation. 
         [0032]    Referring to  FIG. 7 , the multi-edged knife blade element  16  of  FIG. 1  is configured as a glazier blade, shown generally at  70 . The multi-edged glazier blade  70  has a sharp edge  73  and two locating holes  74 . The multi edge blade has two sharp corners suited for cutting into rubber bead of glass windows at  72 . This multi-edged glazier blade may be used in the forward direction or reversed direction for left-handed or right-handed operation. 
         [0033]      FIG. 8A  illustrates a side view of an alternate embodiment of a transversely angulated utility knife  80 . In this embodiment, the utility knife comprises a blade-holding portion  81  and an offset handle portion  85 . The blade-holding portion has a planar bottom wall  82  that, in use, is positioned on surfaces substantially perpendicular to the material to be cut. An interior blade-supporting surface  83 , such as a planar channel substantially adjacent to the bottom wall  82  and dimensioned for holding a flat blade  84 , is configured as a plane at an angle  90  between about 2° and 10° to the plane of the bottom wall  82 . The blade-supporting portion  81  further includes a tip portion adjacent to one end of the bottom wall  82  that has a slot-shaped opening or through which a blade  84  extends. The offset handle portion  85  is offset a sufficient distance from the bottom surface  82  so as to allow room for a user&#39;s hand. Alternatively, the handle portion may be angulated from the blade-holding portion at an angle to the bottom wall  82  as illustrated in phantom at  86  (and as illustrated in  FIG. 1 . In either form, the offset handle  85  or  86  extends from the blade-holding portion  81  at an end opposite the blade  84 . Although illustrated as extending behind the blade  84 , the offset handle  85  may also extend above the blade (much like old-fashioned irons) without departing from the invention. 
         [0034]      FIG. 8B  illustrates the blade-holding portion  81  of a utility knife in use adjacent a surface  89 . With the planar bottom surface  82  adjacent to the surface  89 , the blade  84  can bend at  87  so as to align in a parallel manner with the surface  89 . So configured, the bade  84  is positioned to cut items perpendicular to the surface, such as adjacent drywall, linoleum flooring at a corner with a wall, roof shingles adjacent a vertical wall, etc. 
         [0035]      FIG. 8B  also illustrates how the utility blade configuration positions the blade  84  on the working surface  89  with a smooth bottom surface  82  that will not scratch or mar the surface  89 . The blade holding portion  81  includes a toe-in-shoe attachment  23  which works in combination with a threaded fastener  20  at a distal location on the handle  85   a ,  85   b ,  86  to securely clamp the blade  84  against the blade-supporting surface  83 . When assembled, a toe portion  24  of the upper blade portion  85   a  slides into a slot or shoe portion  23  in the lower handle portion  85   b  to form a pivot point for clamping the blade against the blade-supporting surface  83 . Providing the clamping force with a toe-in-shoe  23  attachment at the blade exit portion of the utility knife enables the blade to be securely clamped to the blade-supporting surface  83  without using a fastener in the blade holding portion  81 . This configuration is beneficial because clamping the blade holding portion  81  could cause the bottom wall  82  to have protrusions (e.g., the head or tip of a threaded fastener) which could scratch or gouge the working surface  89 . 
         [0036]      FIG. 8C  shows the bottom portion of the utility knife handle  85   b . As mentioned above, the bottom portion of the utility knife handle  85   b  includes the shoe portion  23  and an interior blade-supporting surface  83 . The interior blade-supporting surface  83  is configured as a plane at an angle  90  between about 2° and 10° to the plane of the bottom wall  82 . So configured, a blade  84  in contact with the interior blade-supporting surface  83  will extend from the tip portion (below shoe  23 ) at a slight angle to the bottom surface. 
         [0037]      FIG. 8D  shows the top portion of the utility knife handle  85   a . As mentioned above, the top portion of the utility knife handle  85   a  includes the toe portion  24  which fits into the shoe portion  23  when assembled to provide a clamping pivot. The utility knife handle  85   a  also includes an interior (when assembled) blade-clamping surface  88 . The blade-clamping surface  88  is sized to fit within the planar channel in the bottom portion  85   b  and cooperate with the blade-supporting surface  83  to securely clamp onto the blade  84  in the assembled configuration. The blade-clamping surface  88  is configured so its bottom portion forms an angle  90  with the horizontal of between about 2° and 10°, thereby cooperating with the blade-supporting surface  83  of the bottom portion of the utility knife handle  85   b  to secure the blade  84  at the angle  90  to the bottom surface  82 . In the illustrated embodiment, the pin or lug protrusion  18  is positioned in the blade-clamping surface  88  to engage a hole in the blade  84  to prevent sliding when the blade  84  is clamped in the assembled handle  81 . 
         [0038]    Additional details of the utility knife  80  may be similar to the other embodiments described herein. Similarly, blade  84  may be multi-edged and can have any previously-described form. 
         [0039]      FIGS. 9A and 9B  illustrate another alternate embodiment for a blade-holding portion  91  of a utility knife in which the blade  94  is mounted in a retractable and/or selectively-positionable manner. As illustrated in the sectional side view of  FIG. 9A , a blade-holding portion  91  includes a planar bottom surface  92  and a blade-supporting surface  93  that is angled at a slight angle between about 2° and 10°, preferably at about 5°, to the horizontal plane defined by the planar bottom surface  92  of the blade-holding portion  91 . The blade  94  is supported in an adjustable/retractable carriage  95  that can be selectively positioned at various positions along the blade-supporting surface  93 . The carriage  95  includes a resilient beam with a retainer  96  and an actuator  97 . The resilient beam works cooperatively with a retainer slot  98  to secure the carriage  95  in specific locations of blade deployment. As illustrated in  FIGS. 9A and 9B , when a user depresses the actuator  96 , the retainer  96  drops below the retainer slot  98  and can be moved to another position within the retainer slot  98 . When the carriage  95  is repositioned in this manner, the blade  94  is also repositioned. The retainer slot  98  can include multiple openings dimensioned for accepting retainer  96  so that the blade  94  can be extended from the blade-holding portion  91  differing amounts. The retainer slot  98  may further include a continuous portion that allows the actuator  97  to extend through the slot  98 . While illustrated in a particular form, numerous other forms of this embodiment are also possible. Examples of similar adjustable/retractable carriage structures that can be employed include those disclosed in U.S. Pat. Nos. 2,548,797, 2,601,723, 4,558,517, 4,955,138, and 5,433,004. 
         [0040]    While numerous embodiments have been illustrated, note that the drawings are not necessarily to scale and do not necessarily illustrate correct angular dimensions. Numerous dimensional modifications can be made within the scope of the appended claims. 
         [0041]    In a basic embodiment, the utility knife comprises: a blade-holding portion that comprises a planar bottom wall, a planar channel substantially adjacent to the bottom wall and dimensioned for holding a flat blade in a plane at an angle between 2° and 10° with respect to the bottom wall, and a tip portion adjacent to the bottom wall and having a slot-shaped opening in communication with one end of the planar channel; a toe-in-shoe attachment; and a handle portion offset from the blade-holding portion at an end opposite the tip. 
         [0042]    Optional variations of this embodiment include: those further comprising a multi-edged blade secured in the planar channel and extending through the slot-shaped opening in the tip; those further comprising a locating lug in the planar channel and a locating hole in the multi-edged blade; those wherein the multi-edged blade has at least 4 edges; those further comprising a blade carriage means for holding a multi-edged blade and positioning the multi-edged blade at plural locations along the planar channel; those wherein the planar channel is at an angle of about 5° with respect to the bottom wall; those wherein the handle portion comprises a spare blade storage compartment; those wherein the handle portion is offset at a fixed angle from the blade-holding portion; those wherein the handle portion offset and substantially parallel to the blade-holding portion; and those further comprising: a multi-edged blade; and a blade carriage means for holding the multi-edged blade and positioning the multi-edged blade at plural locations along the planar channel, wherein the planar channel is at an angle of about 5° with respect to the bottom wall. 
         [0043]    In another embodiment, the utility knife comprises a lower portion, an upper portion, means for fastening the lower and upper portions, and a flat blade held between the upper and lower portions, wherein the lower portion comprises a lower blade-holding portion with a planar bottom wall, a planar channel dimensioned for holding the flat blade in a plane at an angle between 2° and 10° with respect to the bottom wall, and a tip portion having a slot in a lower portion and a toe-in-shoe attachment. Further, a lower handle portion may be offset from the blade-holding portion at an end opposite the tip portion, and the upper portion comprises an upper blade-holding portion with a planar blade-claimping plate dimensioned to fit the planar channel for holding the flat blade, the blade-claimping plate having a tip dimensioned to fit the slot in the lower portion to form the toe-in-shoe attachment and position the blade in a lower portion of the slot, and an upper handle portion offset from the blade-holding portion at an end opposite the tip. 
         [0044]    Optional variations of this embodiment include: those wherein the means for fastening the lower and upper portions comprises a fastener between the upper and lower handle portions; those wherein the fastener between the upper and lower handle portions is a screw; those wherein the flat blade comprises at least 4 edges, those wherein the flat blade further comprises at least one locating hole, and one of the channel and the blade-clamping plate include at least one locating pin, lug or stud for engaging the locating hole in a blade; those wherein the upper handle portion and lower handle portion are offset at a fixed, obtuse angle between about 135 degrees to about 150 degrees; those wherein the planar channel is dimensioned for holding the flat blade in a plane at an angle of about 5° with respect to the bottom wall; those wherein the upper and lower handle portions form a spare blade storage compartment; those wherein the upper and lower handle portions are offset at a fixed angle from the upper and lower blade-holding portions; and those wherein the upper and lower handle portions are offset and substantially parallel to the upper and lower blade-holding portions. 
         [0045]    A transverse angulated utility knife has been described. It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the scope of the invention disclosed and that the examples and embodiments described herein are in all respects illustrative and not restrictive. Those skilled in the art of the present invention will recognize that other embodiments using the concepts described herein are also possible. For example different locating member mechanisms and blade clamping means may be used to retain the multi-edged utility knife blade in the device. Further, any reference to claim elements in the singular, for example, using the articles “a,” “an,” or “the” is not to be construed as limiting the element to the singular.