Patent Document

FIELD OF INVENTION 
     The present invention relates to hammers, and more particularly to a hammer with a unique head shape and improved one-handed nailing configuration. 
     BACKGROUND 
     Conventional hammers typically include a head and a handle. During use, a strike surface disposed on the head of the hammer is configured to strike against an object, such as a nail. Placing the nail with fewer strikes, with fewer failures, less concussive vibration and less energy output from the user are some objectives of hammer makers. 
     The common use of nail-starters on hammers has partially overcome the problem of requiring two hands to start a nail and hence removed some of the risk of injury to fingers. Many available hammers have a nail-starter located on the top front portion of the head. A lateral groove, configured to a length of at least 3.5 cm (1⅜ in.) from bell face to partial nail starter face, with a recessed magnet that retains the nail shank. The nail head rests in a generally rounded opening with a gradually sloping partial strike face that extends upward, supporting only a portion of the common nail head. This partial strike face is constructed so as to apply a limited amount of force to the nail head before the nail slides out from the nail head opening and loses contact. Hence the nail shaft is implanted to a shallow depth within the work piece surface. It is an acceptable, but not a consistently reliable means of nail starting and this is perhaps why it often referred to as an optional hammer feature, (eg., U.S. Pat. No. 8,047,099 B2) which states: The nail starter arrangement that includes the groove  64 , magnet  67 , and the surface  69  are optional. 
     There are a number of prior art nailing tools that have approached the problem of placing a nail that has been retained by the hammer. One technique, used in U.S. Pat. No. 5,894,764, confines and therefore restricts the nail head movement with both a vertical and horizontal wall and is only capable of a placing the nail to limited depth in a work piece. This typifies the fixed nail head nail starter method, whereby any nail depth placement in the work piece more than a minimal amount can result in a bent head, bent nail shaft or misdirected nail shaft. There are a number of limited nail starter methods and tools available, including commonly available nail-starters disposed on typical nailing hammers. Some relevant prior art that employ typical and alternate methods are:
     Pat. US 20110314971 A1
 
Which incorporates a nail magazine and mechanism to deliver nails.
   U.S. Pat. No. 4,273,172 A
 
Which offers a limited force strike with a restricted nail head.
   U.S. Pat. No. 2,597,876 A
 
Which offers a fixed head holder and limited depth placement of the shaft.
   U.S. Pat. No. 4,193,433 A
 
Which retains the nail head with a hook beneath claw and offers limited nail shaft depth.
   U.S. Pat. No. 6,301,996 B1
 
Which offers a limited depth with a multiple angle restriction upon the nail head.
   

     These methods either confine and restrict the nail head or deliver a limited glancing strike. If the nail head is restricted the friction and forces that act upon the nail head cause it to be misdirected or cause the nail shaft to bend. The limited glancing strike of the typical partial strike face nail-starters can only drive the nail shaft in to a limited depth. These nail-starters are configured with only a limited amount of weight directly behind the partial nail head strike face. 
     When using the typical integrally formed nail-starter, the second strike, after initially planting the nail, is critical. The shallow depth of the initial nail start makes the successive strike, usually the most forceful, also the most likely to produce failure. This second blow requires more skill and accuracy to ensure an acceptable continuation of the nail placement, sometimes resulting in bent nail shafts or nails completely ejected from the work piece. If the second strike is successful it is commonly followed by a number of additional strikes, each one having a level of difficulty and having the possibility of bending or misdirecting the nail. The total number of strikes required is usually between 4 and 6, depending on, among other factors, nail size and desired depth. 
     Magnetic face specialty tools, usually referred to as tack hammers, roof paper hammers or upholstering hammers, have existed for more than one hundred years. These tools require specialized fasteners that typically have one or more of the following attributes; sharper points, shorter shafts, reinforced heads and/or oversized heads. Some prior art examples of tack hammers are as follows:
     Magnetic tack-hammer U.S. Pat. No. 840,441 A   Magnetic tack-hammer U.S. Pat. No. 710,615 A   Tack hammer U.S. Pat. No. 2,433,223 A   Nail or tack holding attachment for hammers U.S. Pat. No. 469,710 A   Magnetic roofing hammer U.S. Pat. No. 20030140734 A1   Coil Nailer U.S. Pat. No. 20110049215 A1   

     Nail length is also an issue with typical nail starters. In order to function the nail length must be greater than the distance from the nail-starter strike face to the hammer strike face. Typically nails shorter than 3.8 cm (1½ in.) cannot utilize the common bell head nail starter. 
     Another problem with commonly used hammers is that they require a multitude of strikes in order to place the nail in a surface to a predetermined depth. Typically, said depth is more than 80 percent of the nail shaft length. Transporting the hammer weight in an arcing motion for a multitude of strikes in order to achieve this depth causes muscle stress and fatigue in the user. 
     An additional problem with repeated hammer face to nail head strikes is twist and vibration. Common hammer handles have a tendency to transfer torque (the twisting across the longitudinal axis of the handle) and kinetic energy caused by metal impacting metal to the user when a nail head is struck. This problem is compounded by the fact that the most control is required at the moment of impact between hammer face and nail head. The user must grip the handle the tightest at that time. This is when the most kinetic energy and twist occur within the handle, creating faster fatigue and adding more muscle stress to the user. 
     The following is a list of relevant prior art:
     U.S. Pat. No. 20120036965 A1   U.S. Pat. No. 7,404,346 B2   U.S. Pat. No. 4,667,747 A   U.S. Pat. No. 3,788,373 A   EP Pat. No. 2517837 A2   

     This embodiment of the present invention overcomes these problems by combining the nail-start strike and first full strike into one continuous action. Among other factors, it is the freedom of movement between nail head and striking surface afforded by the present invention which thereby allows the nail to be struck with full force. The nail shaft and nail head remain in their original uniform configuration and transverse directly into the work piece. Hence the nail is placed more consistently, with more reliability and with fewer strikes. Since there are fewer strikes required, and commonly only two metal on metal strikes, there is less energy output from the user and less concussive vibration. 
     This embodiment of the present invention is also configured with the preferred distance of 15 mm (⅝ in.) from the front edge, (horizontal cylinder segment strike-face), to the nail-starter strike face. Therefore, said embodiment provides a means for placing any nails minimally longer than 15 mm (⅝ in.). The 15 mm horizontal cylinder segment also provides a means to place nails in one strike to a depth whereby 15 mm of the nail is all that remains above the work piece surface. 
     These and other advantages of the present invention will be readily apparent to those of ordinary skill in the art upon a reading of the following detailed description of presently preferred, but nonetheless illustrative, embodiments of the present invention when taken in conjunction with the accompanying drawings. In this respect, before explaining the current embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of descriptions and should not be regarded as limiting. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of an integrally formed hammer in accordance with an embodiment of the present invention; 
         FIG. 2  is a front elevational view of the integrally formed hammer in accordance with an embodiment of the present invention; 
         FIG. 3  is a rear elevational view of the integrally formed hammer in accordance with an embodiment of the present invention; 
         FIG. 4  is a left hand side elevational view of the integrally formed hammer in accordance with an embodiment of the present invention; 
         FIG. 5  is a right hand side elevational view of the integrally formed hammer in accordance with an embodiment of the present invention; 
         FIG. 6  is a bottom plan view of the integrally formed hammer head in accordance with an embodiment of the present invention; 
         FIG. 7  is a top plan view of the integrally formed hammer head in accordance with an embodiment of the present invention; 
         FIG. 8  is a partial top plan view of the nail-starter strike face and nail groove platform in accordance with an embodiment of the present invention; 
         FIG. 9  is a partial front view of the nail-starter strike face and nail groove platform in accordance with an embodiment of the present invention; 
         FIG. 10  is a partial left hand side elevational view of the integrally formed hammer illustrating different cross-sections of the nail groove platform and nail-starter strike face therethrough in accordance with an embodiment of the present invention; 
         FIG. 10A  is a partial left hand side elevational view of the integrally formed hammer illustrating nail-starter strike face angle; 
         FIG. 11  is a sectional view thereof along the line A-A of  FIG. 10  in accordance with an embodiment of the present invention; 
         FIG. 12  is a sectional view thereof along the line B-B of  FIG. 10  in accordance with an embodiment of the present invention; 
         FIG. 13  is a sectional view thereof along the line C-C of  FIG. 10  in accordance with an embodiment of the present invention; 
         FIG. 14  is a sectional view thereof along the line D-D of  FIG. 10  in accordance with an embodiment of the present invention; 
         FIG. 15  is a partial left hand side sectional view of the nail-starter strike face and horizontal cylinder segment with a nail disposed therein to demonstrate the use of the integrally formed hammer in accordance with an embodiment of the present invention; 
         FIG. 16  is a partial left hand side sectional view of the nail-starter strike face and horizontal cylinder segment with a nail head against the nail-starter strike face to demonstrate the use of the integrally formed hammer in accordance with an embodiment of the present invention; 
         FIG. 17  is a left hand side elevational view to illustrate strike face angles and center axis weight distribution of the integrally formed hammer in accordance with an embodiment of the present invention; 
         FIG. 18  is a partial left hand side view with nail head engaged by hammer claw to demonstrate the use of a secondary leverage point of the integrally formed hammer in accordance with an embodiment of the present invention; 
         FIG. 18A  is a top plan view of another embodiment with reduced bifurcated claws configured so as to primarily utilize an alternate leverage point; 
         FIG. 19  is a left hand side view of prior art that shows a typical configuration of mass and the positioning of nail and nail starter during the striking action; 
         FIG. 20  is a left hand side view that shows a preferred configuration of mass and the positioning of nail and nail starter strike face during the striking action; 
     
    
    
     FIGURE REFERENCE NUMERALS 
     
         
           36 —hammer 
           37 —head 
           38 —handle 
           40 —upper handle portion 
           42 —lower handle portion 
           43 —butt-end portion 
           46 —nail-starter strike face neck 
           48 —nail-starter strike face 
           50 —horizontal cylinder segment 
           52 —horizontal cylinder segment strike-face 
           53 —horizontal cylinder segment chamfer 
           54 —magnet 
           56 —magnet opening 
           58 —semi-circular nail head opening 
           60 —v-shaped nail shaft groove 
           62 —head body 
           64 —claw nail remover 
           66 —bell neck 
           68 —bell 
           70 —bell strike face 
           71 —bell chamfer 
           72 —lower handle covering 
           74 —front finger grip area 
           76 —rear finger grip area 
           78 —nail 
       
    
     BRIEF DESCRIPTION OF THE INVENTION 
     One embodiment of the present invention consists of a curved head  37  disposed on the upper handle portion  40  of a curved handle  38 . The curved nail-starter strike face neck  46  tapers so as to be reducing in diameter as it extends away from the center weight area of the head  37  and towards the nail-starter strike face  48 . Said curved neck then extends further as a horizontal cylinder segment  50 . In this segment a v-shaped nail shaft groove  60  with a recessed magnet  54  retains the nail while it is transported to the work piece surface in a typical manual nailing action. 
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1, 2 and 3  show a hammer  36  in accordance with an embodiment of the present invention. The hammer  36  includes a handle  38  and a head  37 . The handle  38  includes a lower portion  42  and an upper portion  40 . The head  37  is disposed on the upper portion  40  of the handle  38 . The head  37  includes two striking surfaces  48  and  52  disposed at one end of the nail-starter strike face neck  46  and a bell neck  66  and bell strike face  70  disposed on the adjacent end. 
     The hammer  36  includes the overall length dimension (OAL). In one embodiment, as shown in  FIGS. 4 and 5 , the overall length dimension (OAL) of the hammer  36  is measured along (or relative to) a central vertical axis A-A of the hammer  36 . The (OAL) of one embodiment of the present invention as measured along the axis A-A is preferably 38-45 cm (15-18 inches). 
     In one embodiment, as shown in  FIGS. 6 and 7  the head  37  is configured with a curved nail-starter strike face neck  46  tapering so as to be reducing in diameter as it extends away from the center weight area of the head  37  and towards the nail-starter strike face  48 . The head  37  is generally curved whereby the horizontal center axis aligns with a typical arcing swing plane of the user when driving a nail into a work piece. The nail-starter strike face  48  diameter, as shown in  FIG. 14  with a sectional view taken along the line D-D of  FIG. 10 , to head body  62  diameter is configured with a ratio of 1:2.2. 
     In one embodiment, the head  37  of the hammer  36  is integrally formed with the upper handle portion  40 , as shown in  FIGS. 1-5 . The integrally formed handle  38  is made of metal, a composite material, or a synthetic material. In another embodiment, the head  37  and the handle  38  are formed separately and then connected to one another. Any suitable manner of connecting the head  37  and handle  38  may be employed. In this embodiment, the handle  38  shaft can be made from a different material than the head  37 , such as wood, aluminum, a plastic material, a fiberglass material, or other suitable material. 
     As shown in  FIGS. 1-5 , the hammer  36  includes a manually engageable lower handle covering  72 . In one embodiment, the lower handle covering  72  is simply the outer surface of the handle material (e.g., wood or metal). In another embodiment, the manually engageable lower handle covering  72  of the hammer  36  is molded onto an inner or core portion of the lower handle portion  40 . In one embodiment, the lower handle covering  72  is made of a rubber based material, a plastic based material or other suitable material. Optionally, the lower handle covering  72  can be ergonomically shaped. For example, a plurality of ridges spaced longitudinally along the front finger grip area  74  and the rear finger grip area  76 . As shown in  FIGS. 1-5 , the lower handle covering  72  ergonomically includes an extended toe on the front facing edge of a butt-end portion  43 . 
     The upper handle portion  40  is configured likewise to provide durability and/or strength. It is configured with an I-shape cross sectional profile to provide a beneficial distribution of mass. The I-shape cross-sectional profile includes front and rear flanges and connecting web. Front flange preferably provides a broad surface adapted to reduce damage to handle  38  and/or a target caused by striking contact there-between, such as due to an overstrike. Web preferably resists bending and provides strength for handle  38  to allow generation and delivery of substantial striking forces by striking surface. 
     Yet another embodiment would configure the head body  62  in an increased aerodynamic, non-spherical shape, whereby the generally curving and tapered nail-starter strike face neck  46  transverses the bilateral axis of the head  37  and upper handle portion  40  and thereby extends as the bell neck of the adjacent strike face bell. 
     As shown in the partial views of  FIGS. 8-10 , a grooved horizontal cylinder segment  50  extends from the lower portion of the nail-starter strike face neck  46 .  FIG. 8  shows a magnet  54  is located in the opening  56  of the v-shaped nail shaft groove  60 . The magnet opening is 5 mm ( 3/16 in.) in diameter and with the perimeter disposed 2 mm ( 1/16 in.) from the front wall of the semi-circular nail head opening  58 . The groove  60  is constructed and arranged to receive and retain a nail  78 , (shown in dashed lines in  FIG. 10 ), therein when the nail  78  is disposed in an initial nail driving position to facilitate the start of a nail driving operation. 
     Also shown in  FIGS. 8-10 , is a semi-circular nail head opening  58  disposed between the v-groove  60  and the nail-starter strike face  48 . Said opening is constructed and arranged to provide open space for the head of a nail  78 . Thus, the v-groove  60  and the magnet  54 , combined with the force and momentum of the hammer  36 , act together to position and to initially connect the nail  78  with a work piece. The nail-starter strike face  48  is constructed and arranged at an angle of 81 degrees in relation to the v-groove longitudinal axis. The width of the nail head opening  58  as measured along the longitudinal center axis of the neck is 4 mm (⅛ in.). 
       FIG. 10  shows a partial left hand side elevational view of the nail-starter strike face neck  46  and horizontal cylinder segment  50  of the hammer  36  illustrating different cross-sections being taken therethrough in accordance with an embodiment of the present invention. 
       FIG. 10A  shows a partial left hand side elevational view of the nail-starter strike face neck  46  and horizontal cylinder segment  50  of the hammer  36  whereby B represents a nail-starter strike face  48  angle of 81 degrees relative to the horizontal cylinder segment center line marked as A-A. 
       FIGS. 11-14  show progressive cross-sectional views of the horizontal cylinder segment  50  and the v-shaped nail shaft groove  60  of the hammer  36  taken along various sections of  FIG. 10  (eg., at lines A-A through D-D) moving from the horizontal cylinder segment strike-face  52  of the head  37  to the nail-starter strike face  48  (as shown in  FIG. 10 ) of the head  37  of the hammer  36 . 
       FIG. 11  shows a cross-sectional view of the head  37  of the integrally formed hammer  36  taken along the line A-A of  FIG. 10 . It shows the leading edge of the horizontal cylinder segment strike-face  52  and the angles of the v-shaped nail shaft groove  60  walls. In this diagram B represents 60 degrees. 
       FIG. 12  shows a cross-sectional view of the head  37  of the integrally formed hammer  36  taken along the line B-B of  FIG. 10 . The opening  56  for receiving the magnet  54  is shown in the cross-sectional view. 
       FIG. 13  shows a cross-sectional view of the head  37  of the integrally formed hammer  36  taken along the line C-C of  FIG. 10 . The semi-circular nail head opening  58  for receiving the nail head is shown in the cross-sectional view. The hatched area indicates a cross-sectional view of the horizontal cylinder segment as it forms the perimeter of the nail head opening. 
       FIG. 14  shows a cross-sectional view of the head  37  of the integrally formed hammer  36  taken at an 81 degree angle in relation to the horizontal axis of the v-shaped nail shaft groove  60  along the line D-D of  FIG. 10 . The leading edge of the nail-starter strike face  48  in relation to the hatched area indicating the connection between nail-starter strike face neck  46  and the horizontal cylinder segment  50 . 
       FIG. 15  shows how the nail starter and nail starter strike face function together. Initial contact with the work piece surface is made by the nail point. This contact between the nail point and the inert mass of the work piece slows the nail movement. The nail point is therein connected to, and in that manner, part of the work piece. Kinetic energy from said contact is minimal and dissipates quickly. The hammer  36  continues toward the work piece so as to cause the nail shaft to transverse laterally along the v-groove  60  toward the nail-starter strike face  48 . Hence the nail head is thereby impacted by the nail-starter strike face  48 . This impact against the lower region of the nail head applies force against the upper portion of the nail shaft, thereby causing it to move out from the v-groove  60  and disconnect from the magnetic field of the magnet  54 . Hence, shifting of the nail head on the nail-starter strike face  48 , as shown in  FIG. 16 , aligns the nail shaft to be perpendicular to the nail-starter strike face. Said alignment thereby allows for the direct transference of kinetic energy from the weight and momentum of the head and all other connected mass to drive the nail shaft, which is already connected to, and therefore part of, the work piece, deeper into the work piece. Said transference of energy becomes more like a traditional hammer strike on a nail head. The magnet  54  and the nail shaft support  60  perform the task of a nail starter and the nail-starter strike face  48  acts as the main strike force applied to the nail head and shaft. 
       FIG. 17  shows a left profile view of the integrally formed hammer  36  in accordance with an embodiment of the present invention. In non-limiting examples, the weight of the integrally formed head  37  is nominally between 510 and 907 grams (18 and 32 ounces); and the overall length dimension (OAL) of the integrally formed hammer  36  is between 38 and 45 cm (15 and 18 inches). In one embodiment, the handle  38  and the head  37  of the hammer  36  are made from steel material. 
       FIG. 17  also shows the head  37  of this embodiment is disposed back from the center of balance, indicated by the bisecting broken line of Y-Y. Said position of the head  37  behind the center axis allows for a greater draw-back distance between nail point and strike surface when the hammer  36  is used in a typical arcing motion. In this configuration the upper handle portion  40  curves generally back from the axis of center balance, defined by the vertical broken line marked Y-Y until the leading edge of the upper handle portion  40  vertically aligns with the rear edge of the lower handle portion  42 . This alignment is indicated in by the broken line marked H-H. 
     Also shown in  FIG. 17 , indicated by the broken line marked U, is the distance between the nail-starter strike face  48  and the bell strike face  70 . For the purpose of OAL, measurement of said U shall represent head  37  length. The ratio of U to handle length in this embodiment of the present invention is 1:2.25 
       FIG. 17  further indicates the angles of head  37  strike faces in relation to the handle  38  center of balance as defined by the vertical broken line marked Y-Y. The bell strike face  70  angle, indicated as S, is configured at 81 degrees relative to the broken vertical line marked Y-Y. The horizontal cylinder segment strike-face  52  angle, indicated as R, is configured at 99 degrees relative to the broken vertical line marked Y-Y. 
       FIG. 18  shows a bifurcated claw nail remover  64  centrally located on top of the head body  62  of one embodiment provides and leverage point, indicated with an arrow as J in conventional use pulling nails. During a nail pulling operation the top edge of the nail-starter strike face neck  46  provides for a second leverage point, shown in  FIG. 18  as point K, for use with said bifurcated claw. This function could be enhanced by reducing the overall size of the bifurcated claw as shown in  FIG. 18A . 
       FIG. 19  shows the typical prior art configuration of a nail starting hammer. Illustrated is the position of greatest nail impact force. A minimal amount of weight and mass is directed to a portion of the nail head with a glancing blow before it loses contact with the strike face. 
       FIG. 20  shows an embodiment of the present invention to illustrate the configuration of mass and positioning of nail starter strike face in relation to nail head. Illustrated is the position of greatest nail impact force. A substantial amount of weight and mass is directed to the entire nail head and sustains contact for the complete action of driving the nail substantially into the work piece. 
     While these descriptions contain many specificities, they should not be construed as limitations on the scope, but rather as an exemplification of one (or several) embodiment(s) thereof. Many other variations are possible. 
     Other Advantages of the Invention 
     Nail insertion depth is determined by the distance the horizontal cylinder segment  50  extends outward from the nail-starter strike face  48 . In some instances it is beneficial to predetermine the depth to which nails are implanted into the work piece. Hence the horizontal cylinder segment  50  may be configured for alternate nail starter depths. 
     Another advantage of this embodiment of the present invention is the reduction of torque and vibration effects experienced by the user. Common hammer handles have a tendency to transfer torque (the twisting across the longitudinal axis of the handle) and kinetic energy to a user&#39;s hand when a work piece is impacted. In order to maintain force direction and tool positioning, the user grips the handle more firmly while impacting the work piece. This embodiment of the present invention allows the user to do the opposite. Once the vertical descent motion has been initiated the user can loosen their grip on the handle  38  and allow the head  37  to implant the nail while only minimally maintaining contact with the handle  38  so as to guide it. The proximity of nail-starter strike face  48  to nail head thereby transfers less vibration and spread of kinetic energy. 
     Summation 
     Among various other advantages this tested embodiment of the present invention surpasses many objectives of prior art nailing hammer and nail-starter hammers. It places a nail deeper into a work piece with the first strike. It also places the nail more consistently and reliably with fewer strikes, and is capable of placing the nail to a predetermined depth with one strike.

Technology Category: 7