Abstract:
This invention relates to an articulated iron cap for a hand plane. The iron cap pivotally mounts to a hand plane. The iron cap for the hand plane mates to either a beveled down iron or a bevel up iron. One embodiment of the invention has a chip breaker for engaging the iron where the chip breaker pivots approximately perpendicular to the longitudinal axis of the hand plane. A nose piece on the chip breaker may be configured to extend and pivot so as to align with the grind angle on the iron. This invention places a mass near the cuffing edge of the iron which allows for preloading the iron and dampening vibration of the iron. In turn, this all creates a smoother more accurate cut and requires less effort to use.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a Continuation-in-Part and claims priority under 35 U.S.C. § 119 of U.S. application Ser. No. 10/992,583 filed Nov. 18, 2004, which application is hereby incorporated by reference in its entirety. 

   BACKGROUND OF THE INVENTION 
   This invention relates to woodworking tools. Specifically, this invention relates to an articulated iron cap for a hand plane. 
   Hand planes have been used for hundreds of years to smooth the surface of wood. A hand plane works when a woodworker pushes or pulls the plane across the surface of the wood which allows the sharp blade or the plane iron to engage the wood and shear off a thin layer of wood, thereby smoothing the wood surface. 
     FIG. 1  shows an expanded view of a prior art hand plane. The hand plane assembly  10  has a base unit  12 , in which the bottom of the base unit  12  is the sole  14 . In addition, the base unit  12  has an opening in the sole  14  which is called the throat  16 . Attached to the base unit  12  is at least one handle or tote  18 . A device called a frog  20  extends upward from the inside of the base unit  12 . The frog  20  holds the blade or cutter which is known as the iron  28 . The user can turn the depth adjuster  22  which allows the iron  28  to extend farther through the throat  16 . Adjustment of the iron  28  depth allows the iron  28  to engage a deeper or shallower cut in the wood being planed. The lateral adjuster  24  allows the user to adjust the iron  28  into a left or right position. This in turn, allows for deeper cuts on one side of the plane or the other. A bolt inserted near the center of the frog  20  is called the fulcrum stud  26 . This stud  26  allows the iron  28  to be fastened securely to the frog  20 , so as to make a secure, tight fit which holds the iron  28  in place during use. 
   In order for the iron  28  to be of use, it must be sharpened. The sharpened area on an iron  28  is called the bevel  29 . Most prior art hand planes are designed in one of two ways. They either have the iron bevel up, or the bevel down in relation to the sole  14  of the plane. Typically planes that have a down bevel are similar to the design shown in the hand plane assembly  10 . On the other hand, common bevel up irons are used in a different style of hand plane (not shown) which do not have the frog. Instead, the iron  28  lays on an inclined surface on the inside of the base unit  12  without the aid of the frog  20 . This allows a bevel up iron  28  to lie at a much more reclined angle inside the base unit  12  of the plane. 
   A prior art bevel up type iron  28  plane which is not shown, is commonly known to one skilled in the art. A bevel up iron  28  allows a user with the much more inclined angle on the iron  28  to use the plane in more difficult types of wood. The sharper attack angle allows the plane to cut woods with more difficult grain. Thus, each type of plane, bevel up or bevel down, has its own specific purpose. 
   A cap iron  30  is used in conjunction with the iron  28  on bevel down type planes. The cap iron  30  is secured to the iron  28  by the use of a cap iron screw  36 . This cap iron  30  acts as a chip breaker which helps to curl the cuttings cut by the iron  28  before they have a chance to split away from the larger working piece of wood. The end result is that the chip breaker part  38  on forward end of the cap iron  30  as seen in  FIG. 1A , which is the rounded-out bottom portion of the cap iron, is desirable in bevel down type irons  28 . Overall, the chip breaker contributes for much smoother cutting on the work surface of the wood. The iron  28  and the cap iron  30  when bolted together by the use of the cap iron screw  36  become one piece, which is held onto the frog  20  by the use of the lever cap  32 . This lever cap has a lever  34  with a cam on the end which applies pressure against the cap iron  30  to hold the cap iron  30  and the iron  28  assembly in place on top of the frog  20 . The cam on the bottom of the lever  34  causes the lever cap  32  to pivot around the fulcrum stud  26  and remain tight on the cap iron  30  and iron  28  assembly. 
   Typically, most lever caps  32  are of solid construction cast metal with the only moving part as the lever  34 . This allows for a solid lever action while pivoting at the fulcrum stud  26  to allow force on the cap iron  30  to hold it tight. However, other types of lever caps  32  have been developed. For example, U.S. Pat. No. 1,822,520 discloses a clamping lever assembly  40  which is seen in  FIGS. 2 ,  3  and  4 . This clamping lever assembly  40  was comprised essentially of two main sections, the clamping lever main body  44  and the clamping lever tip  46 . On the back side near the lever  34  is a spring  42  which helps to hold the lever  34  into place which maintains pressure or tension on the cap iron  30  and iron  28  assembly. The clamping lever main body  44  and the clamping lever tip  46  are held together by a rivet which is loosely fit and allows the clamping lever tip  46  to move a little with respect to the clamping lever main body  44 . On the bottom of the clamping lever tip  46  are two lugs  48 . These lugs also engage the cap iron  30  and iron  28  assembly to apply pressure to the assembly to hold it tight on the plane. The bearing edge  50  is what contacts the cap iron  30  to apply pressure to the iron  28  to hold it tight during operation of the plane. Here again, a fulcrum stud  26  goes through the fulcrum slot  52  to allow the assembly to mount together. 
   One of the problems with existing planes is that frogless planes lack a chip breaker. This can cause a “lever-effect” of a shaving and wood can be “torn” out ahead of the cut. The result is an undesirable rough cut. Another problem with this type of assembly of the prior art, is that the pressure from the lever cap  32  or the clamping lever assembly  40  is applied to the cap iron behind the cutting edge of the iron  28 . This allows the cutting edge of the iron  28  to vibrate and contributes to rough cuts. This creates opportunities for vibration and flex of the iron  28 . This leads to chatter in thin cuts as the iron  28  loads and depends on the user to maintain a rigorous and forceful motion to keep the iron loaded during use. Every cutting edge, whether in wood or metal, needs a load (or bite) to work properly. With hand planes, the load occurs when the cutting edge first encounters the material to be cut. The edge of the blade or iron  28  deflects slightly and as long as there is significant forward motion of the plane, the iron  28  remains loaded and cuts the material. 
   The primary object of the present invention is to provide an improved plane iron cap. 
   It is a further object of this invention to allow the iron to be tensioned or loaded while locked in place. 
   It is a further object of this invention to create the ability to vary the depth of the cut while the iron is locked in place. 
   It is a further object of this invention to add mass and tension to the area of the iron that is unsupported in traditional planes therefore making the iron more rigid. 
   It is a still further object of the invention to create a plane which dramatically dampens vibration during use. 
   It is a further object of the invention to create a cap iron which also functions as a chip breaker. 
   It is a further object of the invention to eliminate the need to separate the iron from the chip breaker on the cap iron prior to sharpening. 
   It is a still further object of the invention to create a seal between the iron and the chip breaker which eliminates tuning of new planes and prevent chips from becoming lodged between the chip breaker and the iron. 
   It is a still further object of the current invention to allow bevel up planes to have the aid of a chip breaker. 
   It is a still further object of the invention to minimize grain lift when using the plane to plane wood. 
   It is a further object of the invention to allow the cap iron to seat throughout the entire lateral adjustment range of the iron. 
   It is a further object of the invention to allow the cap to seat against the iron regardless of the primary grind angle or bevel on the iron. 
   It is a still further object of the invention to add mass to the cutting edge of the iron to act as a vibration dampener. 
   It is a still further object of the invention to create a plane which can eliminate the use of a frog while still having a chip breaker. 
   It is a further object to move the flexing point of the iron from the fulcrum stud down closer to the cutting edge of the iron. 
   A further object is the provision of the articulated plane iron cap which is economical to manufacture, durable in use, and efficient in operation. 
   One or more of these or other objects of the invention will be apparent from the specification and claims that follow. 
   SUMMARY OF THE INVENTION 
   The foregoing objects may be achieved by creating a hand plane with a base unit configured for holding an iron wherein the base unit is comprised of a sole and a throat and the iron is configured with a beveled edge which can extend through the throat of the base unit and an articulated iron cap is used to position the iron through the base unit wherein the iron cap is configured to pre-load the iron and also to act as a chip breaker. 
   A further feature of the present invention involves an iron cap which has a pivoting dampner with an extendable pressure bar which traverses in and out of the dampner for engaging the iron and dampering vibration in the iron. 
   A further feature of the present invention involves a hand plane, wherein the iron is configured as either an up beveled iron or a down beveled iron. 
   A further feature of the present invention involves a hand plane, wherein the iron cap is pivotally mounted to the base unit. 
   Another feature of the present invention involves a hand plane, wherein the iron cap is further comprised of a two axis or a three axis chip breaker, and the chip breaker self-aligns with the grind angle on the iron. 
   A still further feature of the present invention is a hand plane wherein the chip breaker is further comprised of a button or a rib, which is configured so as to apply pressure against the iron to pre-load the iron. 
   A further feature of the present invention involves a hand plane, wherein the throat is configured as an adjustable throat. 
   A still further feature of the present invention involves a hand plane, wherein the chip breaker is further comprised of a button or a rib, which is configured so as to apply additional pressure directly behind the bevel to pre-load and dampen the iron. 
   The foregoing objects may also be achieved by creating an iron cap for a hand plane comprising a means for pivotally mounting to a hand plane, an articulating means for tensioning an iron in the hand plane, whereas the articulating means is further configured as a chip breaker. 
   A further feature of the present invention involves an iron cap for a hand plane wherein the iron cap is configured to mate to a bevel down iron or a bevel up iron. 
   A further feature of the present invention is an iron cap for a hand plane wherein the chip breaker is configured with a two or three dimensional axis for engaging the iron plane. 
   A further feature of the present invention involves the iron cap for a hand plane wherein the chip breaker is configured to pivot approximately perpendicular to the longitudinal axis of the hand plane so as to adjust to the angle, or pitch of the iron. 
   The foregoing objects may also be achieved by a hand plane configured to have a base unit with a sole and a throat, at least one handle attached to the base unit, a beveled iron for extending through the throat on the base unit and an iron cap, wherein the iron cap comprises a means for pivotally attaching to the base unit, a means for engaging the beveled iron, and an articulated chip breaker. 
   A further feature of the present invention involves a hand plane wherein the iron cap articulates relatively perpendicular to the longitudinal axis of the hand plane. 
   A further feature of the invention is a hand plane wherein the iron cap further comprises a nose piece, wherein the nose piece is configured to pivot so as to engage varying grind or bevel angles of the iron. 
   A further feature of the present invention involves a hand plane wherein the iron cap further comprises a button, wherein the button is configured to apply additional pressure on the iron. 
   A further feature of the present invention is a hand plane wherein the iron cap further comprises a raised rib, wherein the rib is configured to apply additional pressure to the iron. 
   A further feature of the invention is a hand plane wherein the iron cap further comprises a nose piece, wherein the nose piece is configured to pivot so as to engage tightly regardless of the varying grind or bevel angles of the iron, or manufacturing tolerances. 
   There are several words that need to be defined for the purpose of this invention. This invention is entitled an Articulated Iron Cap for a Hand Plane. The word articulated simply means that the iron cap has joints or segments and is capable of having rotating parts. Another word that needs to be defined is loading. This invention refers to loading of the plane iron. Loading simply means applying pressure against the iron so as to push the lower end of the iron down and back towards the rear of the throat of the base unit with pressure as much as or greater than the pressure that would be applied as the iron is driven into the wood in which it is to cut where the wood would be pushing against the lower edge or the cutting edge of the iron. The current invention allows for the iron to be pre-loaded with a force as much as or greater than the load force of standard hand planes, thereby significantly reducing any flexing, chatter or vibrating of the iron during use. The pre-loading of the iron in the current invention allows for a much smoother cut because the iron does not flex when it is driven into the wood that is being worked. In addition, this pre-loading force allows the depth of cut to be adjusted by adding more loading force to the iron by further tightening a tensioning bolt. In fact, the depth of cut can be finely adjusted up to approximately 0.003″ (0.0762 mm) in this manner. 
   Another word that needs defined is iron. Iron does not refer to the type of material or element in which the current invention is made of. Rather, iron is a term commonly known in the art for the blade or the cutting device which actually cuts the wood for a hand plane. Therefore, a cap iron (or iron cap) is a cap that simply goes over the top of the iron, which can be made of many different materials including steel, cast iron, brass, or other similar metals. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an expanded view of a typical hand plane in the prior art. 
       FIG. 1A  shows a lower portion of the assembly between a cap iron and the iron of the prior art. 
       FIG. 2  shows a side view of an alternative jointed cap iron in the prior art. 
       FIG. 3  shows an expanded side view of an alternative cap iron in the prior art. 
       FIG. 4  shows the bottom view of an expanded alternative cap iron in the prior art. 
       FIG. 5  shows an isometric view of one embodiment of the current invention used in a hand plane. 
       FIG. 6A  shows an embodiment at an articulated plane iron cap of the current invention engaging a bevel up iron. 
       FIG. 6B  shows an alternative embodiment of an articulated plane iron cap invention engaging a bevel down iron. 
       FIG. 6C  shows another embodiment of an articulated plane iron cap of the current invention engaging a bevel up iron. 
       FIG. 6D  shows another embodiment of an articulated plane iron cap of the current invention engaging a bevel down iron. 
       FIG. 7A  shows the bottom view of an articulated iron cap assembly used for a bevel up plane. 
       FIG. 7B  shows the bottom view of an articulated iron cap assembly used for a bevel down plane. 
       FIG. 7C  shows a bottom view of another embodiment of an articulated iron cap assembly. 
       FIG. 8A  shows a side view of an articulated iron cap assembly for a bevel up plane. 
       FIG. 8B  shows a side view of an articulated iron cap assembly for a bevel down plane. 
       FIG. 8C  shows a side view of another embodiment of an articulated iron cap assembly. 
       FIG. 9  shows a bottom view of the iron cap main body. 
       FIG. 10  shows a side view of the iron cap main body. 
       FIG. 11A  shows a sectional view through the center of a bevel up plane using the current invention. 
       FIG. 11B  shows a sectional view through the center of a bevel down plane using the current invention. 
       FIG. 11C  shows a partial sectional view of another embodiment of the current invention along lines  11 C in  FIG. 6C . 
       FIG. 11D  shows a partial sectional view of another embodiment of the current invention along lines  11 D in  FIG. 6D . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The invention is an articulated hand plane iron cap for use on a woodworking plane. One embodiment of the invention is shown in  FIG. 5 . This embodiment of the plane does not incorporate a frog  20 , as is incorporated in the prior art, however, a frog  20  could be used with the current invention. 
   This embodiment of the invention is constructed with a base unit  12  in which the underside of the base unit  12  is called the sole  14 . An opening in the sole  14 , is a throat  16 . The throat  16  can be configured as an adjustable throat, as is common in the art. Attached to the base unit  12  is also one or more totes or handles  18 . The totes  18  allow the user to grip the plane so they can push or pull the plane over the wood surface to be planed however, totes  18  are not necessary. The bevel up iron  28 A rests on the depth adjuster  22  and a portion of the base unit  12  and extends through the throat  16 . The iron  28 A is held to the base unit  12  by the articulated iron cap assembly  60 A. The articulated iron cap assembly  60 A is constructed with an iron cap main body  64  which pivotally mounts to the base unit  12  by the iron cap assembly main pivots  74 . These iron cap assembly main pivots  74  allow the articulated iron cap assembly to pivot back and forth along the iron cap assembly main pivot  74  axis. 
   When the tensioning bolt  62  is screwed into the iron cap main body  64 , it applies pressure to the iron  28 A. The articulating chip breaker  66 A, which is pivotally attached to the iron cap main body  64 , then moves downward after the articulated iron cap assembly  60 A pivots about the iron cap assembly main pivot  74 . Attached to the articulating chip breaker  66 A is a nose piece  68 . As the tensioning bolt  62  is screwed tighter into the iron cap main body  64 , the nose piece  68  engages the iron  28 A. The tighter the tensioning bolt  62  is tightened, the tighter the pressure that is held on the iron  28 A. This pressure or loading allows the articulated iron cap assembly  60 A to hold the iron  28 A into the base unit  12  of the plane. 
   The articulated iron cap assembly  60 A of the current invention allows a hand plane to have a chip breaker  66 A without the use of a cap iron  30 . This chip breaker  66 A applies pressure at the very bottom end, near the cutting edge of the iron  28 A. Putting pressure at the very bottom end directly on the iron  28 A allows the articulated iron cap assembly  60 A to hold the iron  28 A extremely steady which reduces vibration on the iron  28 A, which in turn creates a better cut with the plane. In addition, the articulating chip breaker  66 A adds a large mass coupled directly near the cutting edge of the iron  28 A which further reduces vibration of the iron  28 A and additionally creates a smoother, more accurate, and better cut. 
   As seen in  FIG. 6A , the iron  28 A for this embodiment of the invention has an up bevel  29 A. As discussed above, the iron  28 A is cradled in the base unit  12  and held tightly by the tensioning bolt  62  and the nose piece  68 . The pivoting or articulating of the articulating chip breaker  66 A allows the chip breaker  66 A and the nose piece  68  to pivot so as to engage the bevel  29 A of the iron  28 A.  FIGS. 6C and 6D  show another embodiment of the invention, with an extendible nose piece pressure bar  68 C iron cap assembly  60 C.  FIG. 6C  shows an up bevel iron  29 A and  FIG. 6D  shows a down bevel iron  29 B. 
   As seen in  FIGS. 7A and 8A , the articulating chip breaker  66 A comprises a tension button  80  on the underneath side of the articulating chip breaker  66 A. The combination of the rounded button  80  and the pivoting nose piece  68  allows for a positive engagement on an upper bevel  29 A iron  28 A, even if the bevel of iron  28 A is skewed off center of the longitudinal axis of the plane. The preferred embodiment of the button  80  is rounded, but it can be other shapes. The nose piece  68  pivots along the nose piece pivot  70 . The chip breaker  66 A provides a function of reducing the “lever effect” of a shaving which can create a situation where the wood is “torn” ahead of the cut. Thus, the chip breaker  66 A creates a smoother surface on the planed wood. 
   Another embodiment of the current invention is shown in  FIGS. 6B ,  7 B and  8 B. Here the iron  28 B shown is a bevel down  29 B iron. The bevel  29 B is on the bottom side of the iron. Since the bevel  29 B is now on the bottom side, the articulated iron cap assembly  60 B is able to engage a flat surface of the iron  28 B rather than having to accommodate for the bevel of an up bevel iron such as  28 A. Since the articulated iron cap assembly  60 B is engaging a flat surface on the iron  28 B, the articulated chip breaker  66 B no longer needs the three dimensional pivoting. Rather, the articulating chip breaker  66 B only needs to pivot along the chip breaker pivot  72 . The articulating chip breaker  66 B as seen in  FIGS. 7B and 8B  has a tension rib  82  as opposed to the tension button  80 . This tension rib  82  follows along the surface of the iron  28 B and pivots the articulating chip breaker  66 B along the chip breaker pivot  72  and causes both the tension rib  82  and the bottom edge of the articulating chip breaker  66 B to engage the iron  28 B. The preferred embodiment of the tension rib  82  is flat, but can be other shapes. This engagement holds the iron  28 B in place when the articulated iron cap assembly  60 B is tightened to the iron  28 B by using the tensioning bolt  62  as discussed above where the articulated iron cap assembly  60 B pivots about the iron cap assembly main pivot point  74  to hold the iron  28 B tight against the inner bed of the main base unit  12 . 
   The embodiment of the invention shown in  FIGS. 6C and 6D  with bevel up iron  29 A and bevel down iron  28 B respectively is also shown in  FIGS. 7C ,  8 C,  11 C and  11 D. This embodiment has an extendible nose piece or pressure bar  68 C which extends in and out of the articulating chip breaker/dampner  66 C. This works similar to the embodiments shown in  FIGS. 5 ,  6 A,  7 A,  8 A and  11 A, but in this embodiment the pressure bar  68 C is extendible from the dampner  66 C. This allows pressure to be placed on the iron  28  further from the tension button  80  or tension rib  82 . This greater distance increases leverage thereby increases loading capability on the iron  28 . Additionally, having an extendible pressure bar  68 C allows for engaging the iron  28  closer to the cutting edge when the iron  28  is extended further through the throat  16 . 
   The current invention allows the chip breaker  66 A and  66 B to be pivotally attached to the iron cap main body  64  and eliminates the need for a cap iron  30  of the prior art. Thus, sharpening of the iron  28 A and  28 B can be done without having to follow the extra step of removing a cap iron  30 . In addition, having the extra mass of the chip breaker  66 A and  66 B applying pressure near the bottom cutting edge of the iron  28 A and  28 B allows extra mass to be added to the lower end of the iron  28 A and  28 B near the cutting edge which reduces vibration and creates a smoother, better cut of the wood being planed with less effort. 
     FIGS. 9 and 10  show the bottom view and the side view respectively of the iron cap main body. The name iron cap does not refer to the material makeup of the preferred embodiment of the current invention. Rather, iron cap simply is the name given for the cap which covers the iron  28 A or  28 B otherwise known as the blade for the plane. Calling the blade the iron is standard in the art and thus, the cap covering the iron is commonly known as the cap iron. Therefore, the articulated iron cap can be made of any rigid material. 
   This invention refers to loading of the plane iron. Loading simply means applying pressure against the iron so as to push the lower end of the iron down and back towards the rear of the throat of the base unit with pressure similar to the pressure that would be applied as the iron is driven into the wood in which it is to cut where the wood would be pushing against the lower edge or the cutting edge of the iron. The current invention allows for the iron  28 A or  28 B to be pre-loaded to a force far greater than the load force of standard hand planes, thereby significantly reducing any flexing or vibrating of the iron  28 A or  28 B during use. The pre-loading of the iron  28 A or  28 B in the current invention allows for a much smoother cut because the iron  28 A or  28 B does not flex when it is driven into the wood that is being worked. In addition, this pre-loading force allows the depth of cut to be adjusted by adding more loading force to the iron  28 A or  28 B by further tightening the tensioning bolt  62 . In fact, the depth of cut can be adjusted by approximately 0.003″ (0.0762 mm) in this manner. 
     FIGS. 11A and 11B  show sectional views of the articulated iron cap assembly  60 A and  60 B respectfully. This view shows how the loading of the iron  28 A and  28 B takes place near the cutting edge of the iron  28 A and  28 B. As the tensioning bolt  62  is tightened, the iron cap assembly  60 A and  60 B pivot about both the iron cap assembly main pivot points  74  and the chip breaker pivot  72  to allow the chip breaker  66 A and  66 B to self-align with the angle of the iron  28 A and  28 B. 
   Similarly,  FIGS. 11C and 11D  show sectional views of the articulated iron cap assembly with extendible nose  60 C. These views show the loading of the iron  28  with nose piece pressure bar  68 C extended and retracted. The pressure bar  68 C is extended in and out by a threaded extendible nose pivot  70 C. The pivot  70 C threads into the dampner  66 C. It is preferred that the pivot  70 C be knurled or ribbed for ease of turning, but a screw head, hex head, or other device can be used for turning the pivot  70 C. A retaining ring  78  around the nose pivot  70 C houses both the pivot  70 C and the pressure bar  68 C to extend in and out together. The pressure bar  68 C also has an extendible nose barrel  76  which keeps the pressure bar  68 C properly aligned with respect to the dampner  66 C and also provides strength for loading the iron  28 . In use, the extendible nose cap assembly  60 C works similar to articulated iron cap assemblies  60 A and  60 B. 
   The sound made by the preferred embodiment of the current invention during use is different from the sound made by traditional planes. The additional tension or loading on the iron  28 A and  28 B and the additional mass added near the bevel  29 A and  29 B edge changes the natural frequency of the plane. This in turn changes the pitch (sound) and contributes to a reduction in the iron resonating (vibrating). The result is that a reduction in force is needed to work the plane and the iron  29 A and  29 B stays sharp longer. 
   In the drawings and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, these are used in a generic and descriptive sense only and not for purposes of limitation. Changes in the form and the proportion of parts as well as in the substitution of equivalents are contemplated as circumstance may suggest or render expedient without departing from the spirit or scope of the invention as further defined in the following claims.