Abstract:
A selectively operable extendable fulcrum device is described. The device includes a casing with a slot to selectively guide and lock a selectively telescoping rod into place when extended. A ridge on the inside of the casing provides a resting place for a compression spring. The compression spring is operable to selectively retract the telescoping rod back into its retracted position and keeps the telescoping rod and fulcrum head assembly securely in place when retracted. The fulcrum head provides added leverage needed to pull out nails from materials when it is retracted as well as providing added leverage for longer nails when the fulcrum head is extended. The casing and the associated components of the device can be press fit into any conventional hammer head member.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/470,141, filed May 13, 2003, the entire specification of which is expressly incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates generally to fulcrum devices, and more particularly to a selectively operable extendable fulcrum device that can be at least partially disposed within the head of a hammer and is operable to extend out from the head of the hammer to provide added leverage needed to, among other things, pull nails out from material without the need for another object to be placed under the head of the hammer to provide the requisite amount of leverage. 
   BACKROUND OF THE INVENTION 
   Referring to  FIG. 1 , there is shown a claw hammer  10 , in accordance with the prior art. The claw hammer  10  includes a handle member  12  and a head member  14 . The head member  14  further includes a face portion  16 , a throat portion  18 , a neck portion  20 , a cheek portion  22 , an eye portion  24 , and a claw portion  26 . 
   When a claw hammer is used to pull out nails, it is generally considered to be a first class lever. The fulcrum, which is the curved portion of the head of the claw hammer, helps to provide the requisite leverage needed to pull out the nail (i.e., the load) by manipulating the handle of the hammer (i.e., the effort). As the nail is pulled out far enough to cause the face portion of the head of the hammer to contact the work piece, the leverage that was provided by the curve on the head of the hammer is essentially lost. The needed effort to further remove the nail thus becomes greater as the fulcrum moves away from the load In order to regain that leverage. Accordingly, it is generally necessary for the user to place an object (e.g., a block) below the hammer head in order to raise it and move the fulcrum back to its original location, i.e., as close to the load, as possible. Thus, when a claw hammer is used, for example, to remove a nail, especially a long nail, from a piece of material, e.g., such as wood, it is often necessary for the user to place an object below the head of the hammer to help remove the nail, i.e., to provide the requisite amount of leverage. 
   Sometimes, a type of claw hammer is used to tear material apart. This hammer is generally referred to as a rip hammer. A rip hammer is suitable for tearing things apart because it has a flatter head and therefore permits the claws to dig deep into material to pry them apart. Because the head of the rip hammer is relatively flat, it typically lacks the fulcrum capability that is needed to pull out nails, and, as a result, the rip hammer generally performs poorly when attempting to pull out nails. 
   Accordingly, there exists a need for a new and improved fulcrum device, and method for using the same, to provide the requisite amount of leverage to any type of hammer so as to permit the easy removal of objects from various materials. 
   SUMMARY OF THE INVENTION 
   A new and improved fulcrum device is provided, in accordance with the general teachings of the present invention. 
   More specifically, the present invention is primarily directed to a selectively operable extendable fulcrum device that can be inserted into any type of hammer head (e.g., claw, rip, and the like) so as to provide additional leverage for, among other things, pulling out nails without resort to the use of another object placed under the head of the hammer. 
   The extendable fulcrum device preferably includes a substantially cylindrical hollow metallic casing member with a substantially L-shaped slot formed therein. On an internal surface of the casing member, there is preferably provided a ridge surface at one end thereof that permits a metallic compression spring to rest against it. Preferably, a cylindrical metallic rod is provided, with a cam or lobe shaped head at one end thereof and threaded portion at the other end, that preferably moves, through the compression spring, in and out of the casing member while the cam head moves through an axial portion of the slot. 
   A substantially rounded and threaded fulcrum head preferably screws onto the threaded portion of the rod. The compression spring preferably keeps the rod retracted inside the casing member. When the fulcrum head is pulled outwardly from the casing member, the spring preferably compresses, wherein rotating the rod preferably allows the cam head to lock into a perpendicular portion of the slot of the casing member. To retract the fulcrum assembly, the fulcrum head is preferably twisted in the opposite direction so as to allow the cam member to disengage from the perpendicular portion of the slot and slide down along the axial portion of the slot towards the bottom of the casing member. 
   In accordance with a first embodiment of the present invention, a fulcrum device is provided, comprising: (1) a fulcrum member having a convex first major face and an opposed second major face; (2) a stem member extending from the second major face; (3) substantially hollow casing member; and (4) a spring member disposed within the casing member; wherein the stem member is slidably received within the spring member, wherein the stem member is selectively operable for axial movement within the casing member. 
   In accordance with a second embodiment of the present invention, a fulcrum device is provided, comprising: (1) a fulcrum member having a convex first major face and an opposed second major face; (2) a stem member extending from the second major face, the stem member having a protuberance formed at a terminal portion thereof; (3) a substantially hollow casing member having a slot formed in a surface thereof; and (4) a spring member disposed within the casing member; wherein the stem member is slidably received within the spring member, wherein the stem member is selectively operable for axial movement within the casing member, wherein the protuberance is selectively operable to engage a surface of the slot so as to substantially prevent axial movement of the stem member. 
   In accordance with a third embodiment of the present invention, a fulcrum device is provided, comprising: (1) a fulcrum member having a convex first major face and an opposed second major face; (2) a stem member extending from the second flat major face, the stem member having a protuberance formed at a terminal portion thereof; (3) a substantially hollow casing member having a substantially L-shaped slot formed in a surface thereof; and (4) a spring member disposed within the casing member; wherein the stem member is slidably received within the spring member, wherein the stem member is selectively operable for axial movement within the casing member, wherein the protuberance is selectively operable to engage a surface of the L-shaped slot when the protuberance is rotated approximately 90 degrees so as to substantially prevent axial movement of the stem member. 
   Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
       FIG. 1  depicts a side view of a claw hammer, in accordance with the prior art; 
       FIG. 2  depicts an exploded view of a fulcrum device, in accordance with the general teachings of the present invention; 
       FIG. 3  depicts a side view of the fulcrum device in the retracted position, in accordance with one embodiment of the present invention; 
       FIG. 4  depicts a side view of the fulcrum device in the extended position, in accordance with a first alternative embodiment of the present invention; 
       FIG. 5  depicts a partial exploded view of an intended placement of the fulcrum device in the head of a hammer, in accordance with a second alternative embodiment of the present invention; 
       FIG. 6  depicts a partial side view of the fulcrum device in the head of a hammer, wherein the fulcrum device is shown in its retracted position, in accordance with a third alternative embodiment of the present invention; 
       FIG. 7  depicts a partial side view of the fulcrum device in the head of a hammer, wherein the fulcrum device is shown in its extended position, in accordance with a fourth alternative embodiment of the present invention; 
       FIGS. 8–10  depict the major steps of using the fulcrum device in its retracted position to remove an object from a piece of material, in accordance with a fifth alternative embodiment of the present invention; and 
       FIGS. 11–13  depict the major steps of using the fulcrum device in its extended position to remove an object from a piece of material, in accordance with a fifth alternative embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The following description of the preferred embodiment(s) is merely exemplary in nature and is no way intended to limit the invention, its application, or uses. 
   Referring to  FIG. 2 , there is shown a fulcrum device  100 , in accordance with the general teachings of the present invention. The fulcrum device  100  preferably includes a fulcrum head  102  that preferably includes a first major face  104  that preferably has a substantially convex or rounded surface  106  formed thereon and an opposed second major face  108  that has a substantially flat surface  110  formed thereon. Along a central axis of the fulcrum head  102 , an engagement surface  112 , for example, a threaded surface  114 , is preferably provided. The fulcrum head  102  may be comprised of any number of materials, but is preferably comprised of metallic materials. 
   A casing member  116  is preferably provided, wherein the casing member  116  is preferably comprised of a substantially hollow member. In accordance with a preferred embodiment of the present invention, the casing member  116  is preferably substantially cylindrical. The casing member  116  preferably includes two ends  118 ,  120 , respectively, that are preferably open. At one end of the casing member  116 , a ridge or shoulder member  122 , is preferably provided on an inner surface thereof. A slot  124  is preferably formed in a surface of the casing member  116 . In accordance with a preferred embodiment of the present invention, the slot  124  is preferably substantially L-shaped, i.e., it includes an axial portion  124   a  and a perpendicular portion  124   b . The casing member  116  may be comprised of any number of materials, but is preferably comprised of metallic materials. 
   A spring member  126  is preferably provided. In accordance with a preferred embodiment of the present invention, the spring member  116  is preferably substantially cylindrical. The spring member  126  is preferably substantially compressible in response to a compressive forced applied thereto. The spring member  126  may be configured in any number of configurations, but is preferably helically shaped. The spring member  126  is preferably operable to be slidably received within the cavity of the casing member  116 . In accordance with a preferred embodiment of the present invention, the spring member  126  is preferably operable to rest against the ridge member  122  of the casing member  116 . The spring member  126  may be comprised of any number of materials, but is preferably comprised of metallic materials. 
   A rod or stem member  128  is preferably provided. The rod member  128  may be comprised of any number of materials, but is preferably comprised of metallic materials. At one end of the rod member  128 , an engagement member  130 , such as a threaded surface  132  is preferably provided. At the other end of the rod member  128 , a protuberance  134 , such as a cam or lobe shaped member  136  is preferably provided. In accordance with a preferred embodiment of the present invention, at least a portion  138  of the rod member  128  is preferably substantially cylindrical. The rod member  128  is preferably operable to be slidably received within the spring member  126 . In accordance with a preferred embodiment of the present invention, the threaded surface  132  of the rod member  128  is intended to engage the threaded surface  114  of the fulcrum head  102  so as to secure the rod member  128  to the fulcrum head  102 . 
   Referring to  FIG. 3 , the fulcrum device  100  is shown in its retracted position. The tension force of the spring member  126  keeps the rod member  128  in the retracted position until a stronger compressive force is applied to the spring sufficient to overcome its tension force. If that occurs, the rod member  128  is operable to travel along the axial length of the casing member  116 . Additionally, the cam member  136  is preferably configured so as to be operable to slide within the axial portion  124   a  of the slot  124 , when the cam member  136  is parallel to the axial portion  124   a.    
   Referring to  FIG. 4 , the fulcrum device  100  is shown in its extended position. As the cam member  136  moves upwardly in the slot  124  in the direction of arrow A, the spring member  126  is compressed against the ridge member  122  of the casing member  116 . This preferably permits axial movement of the rod member  128  relative to the casing member  116 . When the cam member  136  is in proximity to the perpendicular portion  124   b  of the slot  124 , the cam member  136  is preferably operable to be rotated, in the direction of arrow B, a sufficient amount so as to engage the perpendicular portion  124   b  and prevent axial movement of the rod member  128  relative to the casing member  116 . The direction of, or exact amount of, rotation is not thought to be critical to the success of the present invention, provided that the cam member  136  is able to engage the perpendicular portion  124   b  of the slot  124 , or in the alternative, able to prevent axial movement of the rod member  128  relative to the casing member  116 . In accordance with a preferred embodiment of the present invention, the amount of rotation is preferably about 90 degrees. Once it is preferred to return the rod member  128  to its retracted position, the cam member  136  is rotated in the opposite direction so as to disengage from the perpendicular portion  124   b  of the slot  124  and align with the axial portion  124   a  of the slot  124 , whereupon the rod member  128  will automatically snap back to its retracted position by the action of the spring member  126 . 
   Referring to  FIGS. 5–7 , there is shown an intended placement of the fulcrum device  100  in a hammer  200 , and more specifically, the head portion  202  of the hammer  200 . In accordance with a preferred embodiment of the present invention, an area defining a bore  204  is provided in the head portion  202 . Preferably, the bore  204  is configured so as to provide a relatively tight press fit with the fulcrum device  100 . Optionally, an adhesive material may be employed to secure a portion of the casing member  116  to a surface of the bore  204 , provided that the adhesive material does not interfere with the relatively free movement of the fulcrum member  102  and/or rod member  128 . Once the fulcrum device  100  is fully recessed into the bore  204  in the retracted position (see  FIG. 6 ), only the fulcrum member  102  is plainly visible. In the extended position (see  FIG. 7 ), the fulcrum member  102  and rod member  128  are plainly visible. 
   Referring to  FIGS. 8–10 , there is depicted the major illustrative steps of using the fulcrum device  100  in its retracted position to aid in the removal of an object, in this case a nail  300  from a piece of material, in this case a piece of wood  302 . In  FIG. 8 , the claw portion  304  of a hammer  306  first engages the nail  300 . In  FIG. 9 , the fulcrum member  102  makes contact with the surface of the wood  302  as the claw portion  304  makes further contact with the nail  300 . In  FIG. 10 , the fulcrum member  102  allows the head portion  308  of the hammer  306  to exert greater leverage to the hammer  306  as the handle  310  is pulled in the direction away from the nail  300  and the face portion  312  makes contact with the surface of the wood  302 . At this point, the nail  300 , because of its long length, is still embedded in the piece of wood  302 ; however, if the nail  300  were not very long, it would have most probably been extracted from the piece of wood  302 . 
   In order to extract the nail  300 , it is necessary to extend the fulcrum device  100  from the head portion  308 .  FIGS. 11–13  depict the major illustrative steps of using the fulcrum device  100  in its extended position to remove an object from a piece of material. In  FIG. 11 , the fulcrum member  102  has been extended, via the rod member  128 , and the claw portion  304  of the hammer  306  has reengaged the partially extracted nail  300 . In  FIG. 12 , the fulcrum member  102  permits the application of a relatively great amount of leverage to the hammer  306 , as the handle is pulled in the direction away from the nail  300 . In  FIG. 13 , the nail  300  is finally completely extracted from the piece of wood  302 , as the face portion  312  again makes contact with the surface of the wood  302 . 
   The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and the scope of the invention.