Patent Publication Number: US-6902392-B2

Title: Interference-free cam for hinged-lid lighters

Description:
PRIORITY CLAIM 
   This application claims the benefit of U.S. Provisional Patent Application No. 60/450,270, filed on Feb. 27, 2003. 

   FIELD OF THE INVENTION 
   The present invention relates generally to lighters having curved hinges, and more specifically to a fabricated curved hinged lighter having a cam that provides for decreased interference when the lid of the lighter is opened and closed. 
   BACKGROUND OF THE INVENTION 
   The design of some reusable lighters incorporates a shell comprising an outer case and a cover or lid. A hinge connects the outer case and lid. Internal to the shell is an inside unit which is the working portion of these lighters. The inside unit can be manually removed from the outer case, loaded with fuel, and then manually reinserted into the outer case. 
   Such reusable lighters that have a hinge connecting the outer case and lid employ some form of a cam which is integral to the insert. The cam is used to bias against the lid and hold the lid in the closed position. However, in some lighters, the cam can obstruct the smooth opening and closing of the lid. This interference occurs because the hinges used in some lighters are curved or rounded, but the cams used in these rounded or curved hinge lighters are flat. This configuration results in the flat side of the cam contacting the curved or rounded hinge. 
   Subsequent movement of the flat side of the cam across the curved hinge when the lid is opened and closed can result in interference, thus making it difficult to open and close the lid. This cam to hinge interference can cause undesirable grinding noises as the metal cam digs into the curved hinge when the lid is opened and closed. Associated with the grinding noises are undesirable vibrations when the lid is opened and closed. 
   Another problem the interference causes arises when the insert is manually placed into the outer case during the manufacturing/assembly process of the lighter. The cam to hinge interference can delay the assembly of the lighter because the inside unit has to be adjusted to compensate for the interference. 
   Thus, there is a need for an improved lighter design that resolves the above described problems. There is also a need for the design to add a minimal number of parts and manufacturing steps, while at the same time not significantly increasing manufacturing costs. 
   SUMMARY OF THE INVENTION 
   The present invention meets the above-described needs by providing an interference free cam for use in a lighter comprising a shell having a hollow outer case and a hollow lid or cover attached to the outer case by a hinge. The outer case has a first sidewall disposed in spaced apart relation to a second sidewall, a first end wall disposed in spaced apart relation to a second end wall, a base connected to the first and second sidewalls and first and second end walls, and an outer case opening opposite the base. The first and second end walls are curved. The lid has a first lid sidewall disposed in a spaced apart relation to a second lid side wall, a first lid end wall disposed in a spaced apart relation to a second lid end wall, a cover wall connected to the first and second lid sidewalls and first and second lid end walls, and a lid opening opposite the cover. The first and second lid end wall are curved. 
   A curved hinge attaches to the outer case and lid thus connecting the outer case and the lid. The hinge comprises a hinge outer case portion attached to the second end wall of the outer case, a hinge lid portion attached to an second lid end wall, and a hinge pin. The second end wall of the outer case and the second lid end wall are aligned such that the hinge outer case-portion and hinge lid portion are aligned and fitted together, and secured together by a hinge pin. 
   The hinge outer case portion and hinge lid portion are curved and form a curved hinge surface. The curvature of the hinge is substantially the same as the curvature of the first and second end walls of the outer case and the curvature of the first and second lid end walls. 
   An inside unit is provided having a hollow housing defined by a first unit sidewall disposed in spaced apart relation from a second unit sidewall, a first unit end wall disposed in spaced apart relation to a second unit end wall, and a plate connected to the first and second unit sidewalls, respectively, and first and second unit end walls, respectively. The first and second unit end walls are curved. The inside unit has an opening opposite the plate. The first and second unit sidewalls extend above the plate and form a wind screen. A front and rear pair of lugs extend from the inside unit. The insert is receivable in the outer case. 
   A flint wheel is rotatably mounted between the front pair of lugs and disposed adjacent to a wick. The wick extends from a fuel reservoir defined inside the hollow housing of the inside unit. The hollow housing is filled with an absorbent material, for example cotton and/or rayon. 
   A movable cam is mounted to the rear pair of lugs. The cam has a cam contact surface having curved portions and a flat portion located between the curved portions. The curved portions are for engaging the curved hinge surface. Thus, when the lid is opened and closed, the cam curved portions move across the curved hinge surface. There is low interference between the cam curved portions and curved hinge surface. As a result, grinding noises and vibrations are significantly reduced. Also, manufacturing time is decreased because time does not need to be expended adjusting the inside unit in the outer case. 
   Additionally, the flat portion of the cam contact surface can be used in connection with hinges that are flat. In such an arrangement, the cam flat portion slides or moves over the flat hinge. 
   In another embodiment the cam contact surface is curved from side to side. This curvature allows for sliding contact between matching curved surfaces when the lid is opened and closed thereby decreasing interference. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is illustrated in the drawings in which like reference characters designate the same or similar parts throughout the figures of which: 
       FIG. 1  is a front partly in section elevational view of the lighter with the lid in the open position; 
       FIG. 2  is a right side elevational view of the inside unit of the lighter showing the curved portions of the cam; 
       FIG. 3  is a front elevation view of the inside unit of the lighter showing the curved portion of the cam wherein the cam is in the lowered position; 
       FIG. 4  is a rear elevational sectional view of the lighter shell showing the outer case, lid, curved hinge, and hinge pin; 
       FIG. 5  is a top plan view of the outer case showing curvature of the hinge outer case portion and first outer case end wall and second outer case end wall; 
       FIG. 6  is a bottom plan view of the lid showing the curvature of the hinge lid portion and the first lid end wall and second lid end wall; 
       FIG. 6A  is an exploded top plan view of the open lighter. 
       FIG. 7  is a rear perspective partly in section view of the lighter detailing the curved hinge and curved portions of the cam; 
       FIG. 8  is a rear perspective partly in section view of the lighter showing the curved portions of the cam contacting the curved hinge; 
       FIG. 9  is a top plan view of the inside body unit wherein the cam is in the raised position; 
       FIG. 10  is a front elevational view of the cam showing the curved or rounded portions of the cam contact surface along with a flat contact portion; 
       FIG. 10A  is a right side elevational view of the cam showing the curved portions and flat portion; 
       FIG. 11  is a front elevational view of another embodiment of the cam wherein the cam contact surface is completely rounded or curved. 
   

   DESCRIPTION OF THE INVENTION 
     FIGS. 1-10  show the lighter  10  of the present invention. The invention significantly reduces interference between the cam  37  and curved hinge  20  when the cover or lid  19  of the lighter  10  is opened and closed. This significant reduction in interference is attributed to the curved or rounded portions  39  of the contact surface  38  of the cam  37  that allow for sliding contact between the matching curved surface  21  of the curved hinge  20  and the curved surface of the cam  37 , thus reducing interference. 
   As shown in FIGS.  1  and  4 - 8 , the lighter  10  comprises a shell  12  having an outer case  16  that is hollow and a cover or lid  19  that is also hollow. A curved hinge  20  is connected to the outer case  16  and lid  19 , thus connecting the outer case  16  and lid  19 . As shown in  FIGS. 1 ,  4 , and  5 ,  6 A,  7 , and  8 , the outer case  16  has a first side wall  22  disposed in a spaced apart relation to a second side wall  23 , a first end wall  24  disposed in a spaced apart relation to a second end wall  25 , and a base  26  that is connected to the first and second side walls  22 ,  23 , respectively, and first and second end walls  24 ,  25 , respectively. The outer case  16  has an outer case opening  27  on its side opposite the base  26  that leads to the interior of the outer case  16 . The first and second end walls  24 ,  25 , respectively, are curved as shown in FIG.  5 . 
   The lid  19 , shown in  FIGS. 1 ,  4 , and  6 - 8 , has a first lid sidewall  22 A disposed in a spaced apart relation to a second lid sidewall  23 A, a first lid end wall  24 A disposed in a spaced apart relation to a second lid end wall  25 A, and a cover wall  26 A. The cover wall  26 A is connected to the first and second lid side walls  22 A,  23 A, respectively, and the first and second lid end walls  24 A and  25 A, respectively. The lid  19  has a lid opening  27 A opposite the cover wall  26 A which leads to the lid recess  29 . The first and second lid end walls,  24 A,  25 A, respectively, are curved, as shown in FIG.  6 . When the lid  19  is closed it aligns with the outer case  16  because the curvature of the first and second end walls  24 ,  25 , respectively, and first and second lid end walls  24 A,  25 A, respectively, is substantially the same. 
   The curved hinge  20  pivotally connects the outer case  16  and lid  19  and is shown in  FIGS. 1 ,  4 , and  5 - 8 . As shown, the curved hinge  20  comprises a curved hinge outer case portion  20 A connected to the end second wall  25  of the outer case  16 . The curved hinge  20  also comprises a curved hinge lid portion  20 B connected to the second lid end wall  25 A. It is noted that the curved hinge outer case portion  20 A and curved hinge lid portion  20 B are connected to the insides  64 ,  64 A, respectively, of the second end wall  25  and lid end wall  25 A, as shown in  FIGS. 5 and 6 . A hinge pin  20 C is inserted and secured between the hinge outer case portion  20 A and hinge lid portion  20 B to thus hold the curved hinge  20  together. Also, the curved hinge outer case portion  20 A and curved hinge lid portion  20 B and the first and second end walls  24 ,  25 , respectively, and first and second lid end walls  24 A,  25 A, respectively, have a curvature that is substantially the same. Additionally, the curved hinge outer case portion  20 A and curved hinge lid portion  20 B each have a curved hinge surface  21  as shown in  FIGS. 5-8 . Extending from the curved hinge cover portion  20 B and into the recess  29  defined by the lid  19  is a hinge cross member  58 . 
   The inside body unit  13  (hereinafter inside unit  13 ), shown in  FIGS. 1-3  and  9 , is sized so that it can be manually slid in and out of the outer case  16  and held therein by a friction fit. The inside unit  13 , outer case  16 , and lid  19  are all hollow and can be formed out of sheet metal. In particular, the inside body unit  13  is formed as a sheet metal casing  28  having and having a first casing side wall  42  disposed in spaced apart relation from a second casing side wall  44 , a first casing end wall  46  disposed in spaced apart relation from a second casing end wall  48 , and a plate  50  connected to the first and second casing side walls  42 ,  44 , respectively, and first and second casing end walls  46 ,  48 , respectively. There is an opening  62  in the casing  28  opposite the plate  50 . The first and second casing side walls  42 ,  44 , respectively, extend above the plate  50  and are formed to provide a wind screen  52  so that the lighter will not be extinguished by wind. The first and second casing side walls  42 ,  44 , respectively, are also formed to provide a front pair of lugs  54  and a rear pair of lugs  56 . As shown in  FIG. 9 , the inside unit  13  is provided with a wick  32  that extends downwardly in a central location to the lower end of the inside unit  13 . The hollow inside unit  13  is loaded with a filling of suitable absorbent material (not shown), which may be cotton and/or rayon or other suitable materials or blends and/or combinations thereof, that surrounds the wick  32 , thus filling the space within the metal casing  28 . The absorbent material serves to store fuel used in the lighter  10 . The inside unit  13  also has a flint wheel  31  mounted on a flint wheel pin  35  supported by the front pair of lugs  54 . The flint wheel  31  is disposed adjacent to the flint  60 . The flint  60  can be spring biased into the flint wheel  31  by a spring (not shown) disposed internal to the inside unit  13 . The flint wheel  31  is also disposed adjacent to the wick  32  extending from a fuel reservoir defined inside the metal casing  28 . To generate a spark the flint wheel  31  is spun (manually), thus showering the wick  32  with sparks causing it to ignite. 
   The inside unit body  13  is disposed inside the outer case  16  by means of a friction fit. The friction fit has to be snug enough so that the inside unit  13  does not move inside the outer case  16 , yet is loose enough such that it can be removed for refilling. In order to refill the lighter  10 , the inside unit  13  is removed and lighter fuel is added through the opening  62  in the inside unit  13 . A resilient barrier (not shown) covering the absorbent cotton material is removed manually, and the lighter fuel is added to the absorbent cotton material until a charge of fluid fuel has been delivered. Next, the inside unit  13  is frictionally fit back into the outer case  16 . Casing  28  of the inside unit  13  slides into engagement with the base  26  of the outer case  16  to thus form a fuel storage area that is sealed against leaking by the snug fit. The fit between the inside unit  13  and the outer case  16  is such that the inside unit  13  can be easily extracted and reinserted by hand, without the use of tools. The inside unit  13 , when received in the outer case  16 , does not move about the inside of the outer case  16  under normal operation of the lighter  10 . 
   A cam  37 , as shown in  FIGS. 1-3 ,  7 - 10 A, is provided and is integral to the inside unit  13 . The cam  37  has a recess  47  ( FIG. 10 ) and is mounted to the rear pair of lugs  56  by a cam pin  57  inserted into the recess  47 . A spring  33  is provided having an attachment end  33 A that is connected to the plate  50  in the vicinity of the wick  32 , as shown in FIG.  9 . The free end  33 B of the spring  33  biases against the cam  37 . As shown, the spring  33  may be a leaf-type spring. The other end of the spring  33 , that being the free end  33 B of the spring, is thus disposed between the cam  37  and the plate  50  and forces or urges against the cam  37 . The spring  33  also applies force for biasing the cam  37  against the cross member  58  when the lid  19  is closed in order to keep the lid  19  closed. 
   The cam  37  has a contact surface  38 , shown in  FIGS. 1-3 ,  7 , 8 ,  10 - 10 A that slides across the curved hinge surface  21  of curved hinge lid portion  20 B when the lid  19  is opened and closed. The cam  37  contact surface  38  is provided with curved or rounded portions  39  and a flat portion  40  that is disposed between the curved portions  39  as shown in  FIGS. 1-3 ,  7 ,  8 - 10 A. When the lighter  10  lid  19  is opened and closed the curved or rounded portions  39  of the cam  37  contact surface  38  slide over the curved hinge surface  21  of the curved hinge lid portion  20 B, thus reducing interference between the cam  37  contact surface  38  and curved hinge surface  21 . The curved or rounded portion  39  of the cam  37  also significantly reduces grinding noises and vibrations when the lid  19  is opened and closed. 
   By way of illustration, when the lid  19  shown in  FIG. 1  is closed, the cam  37  rotates counterclockwise. As this occurs the rounded portions  39  of the cam  37  slide over the curved hinge surface  21  and curved hinge lid portion  20 B with a low amount of interference. Then, as the counterclockwise rotation continues, the cam  37  rotates past the dead center position of the pivot  56  and the lid  19  of the lighter  10  closes. The cam  37  also has a lid shutting surface  43 , and the spring  33  biases the lid shutting surface  43  against the cross member  58  to keep the lid  19  of the lighter  10  closed. 
   The flat portion  40  of the cam contact surface  38  is for use with flat hinges (not shown). If the hinge is flat and not curved, then the flat portion  40  of the cam  37  would slide over the flat hinge contact surface of the flat hinge. Thus, the cam  37  is suitable for use in both flat hinged lighters and lighters  10  having curved hinges  20 . 
   In another embodiment shown in  FIG. 11 , the lighter may have a curved hinge surface  21  as described above. The cam  137  may have a cam contact surface  138  that is curved or rounded from one side to the other side such that the entire cam contact surface  138  is curved and there is no flat portion. As shown, the cam  137  may be mounted in the manner previously described. In such an embodiment the likelihood of an interference between the cam  137  and lid  19  is decreased, as there would only be the curved cam contact surface  138  engaging and sliding over the curved surface  21  of the curved hinge  20 . 
   It will be appreciated by those skilled in the art that while the invention has been described above in connection with particular embodiments and examples, the invention is not necessarily so limited and other embodiments, examples, uses, and modifications and departures from the embodiments, examples, and uses may be made without departing from the invention. All of these alternative embodiments are intended to be within the scope and spirit of the this invention.