Patent Publication Number: US-2013236236-A1

Title: Integral mechanical lock

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of application Ser. No. 12/927,474 filed on Nov. 15, 2010. 
    
    
     FIELD 
     The present disclosure relates generally to an integral mechanical lock, and in particular a lock for securely engaging tools in set positions, releasable with pressure for disengagement. 
     BACKGROUND 
     Common tools having mechanical locks include hand saws, lock back knives, multi-tools, ladders and scaffolding. Other type devices that utilize extension locks include tripods for cameras, extension legs, and telescoping handles. All of these commonly used tools utilize various types of locking mechanisms fixated or attached such that a user can position the tool for use and it locks, and manually pressure to unlock. 
     For locking into position support structure tools such as ladders or scaffolding, the prior art includes mechanism that secure about a pivot hinge as used in foldable devices, or secure a slidable engagement for extending type devices. Many varieties of mechanical locks of this type include locking hubs, slider shaft, locking pins, and flip over latches. 
     Locking into position folding ladders is well known in the art and is taught, for example in U.S. Pat. No. 3,692,143 to Kummerlin et al; U.S. Pat. No. 3,794,141 to Sturm; U.S. Pat. No. 4,210,224 to Kummerlin et al; U.S. Pat. No. 4,371,055 to Ashton; and U.S. Pat. No. 4,376,470 to Ashton. Similar to lock back knives or foldable devices having a handle and utensil attached by a pivot, folding ladders generally have positioning pivot joints at the distal ends thereof for permitting movement of the ladder between different angular positions, and releasably fixing the ladder at such selected angular positions. Locking apparatus taught in the prior art involve a plurality of discrete components that work as a system for locking in position. Each component increases the expense of manufacture while requiring maintenance when used. 
     An example of a foldable ladder having multi-position locking mechanism is taught by inventor Leland Boothe in U.S. Pat. No. 4,407,045. Boothe teaches a mechanical lock as constructed within a hub. The hub comprises a tubular metal housing through which one end of a rotatable shaft projects to engage locking pins. The shaft is spring biased toward retraction within the hub, thereby biasing the locking pins toward their locking position in which they project through aligned holes in the hinge plates as contained within the hub. A radially-extending bore is defined through one end of the hub and contains a bias spring which urges a detent ball radially against the shaft. The shaft, in turn, includes plural truncated spherical recesses disposed at angularly spaced positions at a predetermined axial location of the shaft. Each angular position of the recesses corresponds to a different angular lock position, thereby providing a plurality of angular lock positions of the folding ladder. The many components including springs, detent balls, locking pins, detented shafts and a containment hub make the Boothe lock complicated to manufacture, and susceptible to sticking if not kept clean and maintained regularly. 
     An example of an extendable and retractable ladder benefiting from a mechanical lock is taught by Shikun Jian in U.S. Application 2009/0065304. Jian teaches a lock engaged by controlling handles that are spring loaded and attached to locking rods that engage by inserting the locking rods through locking holes that engage the pillars of the ladder at the desired position. Jian&#39;s locking mechanism requires a plurality of components, all susceptible to grime or grit that may decrease free sliding motion, potentially preventing full insertion of the locking rod into the locking holes, causing the ladder pillars to disengage under load. 
     For the devices that include a utensil like a foldable knife, hand saw or file, with a handle pivotally connected, the lock back mechanism is one of the simplest and most reliable methods for locking a tool and handle in position through secure engagement of the moving parts. In practice, the lock back mechanism includes a locking bar substantially parallel to the handle of the tool with one end aligned over the upper back or rear tang of the tool. The locking bar is usually fixated as a separate part to the handle with a rivet, or through pin. As the tool rotates to the open position, the locking bar rides along the rear tang with spring tension, until the locking bar engages a notch in the rear tang, locking the tool in the open position. To unlock, the opposing end of the locking bar is depressed pivoting about a pin the locking bar out of the notch and away from the rear tang allowing the tool to close. 
     Methods of locking a tool to a handle requiring a plurality of components are well known in the art. An example of one alternative method is a locking liner as taught by inventor Ed Halligan in U.S. Pat. No. 6,101,724. The handle has an integral locking bar formed from the same metal as the handle and arranged to exert side forces on the side of the blade as it opens causing wear, and in gritty environments excessive wear. Tolerances for a liner lock design must be precise in order for it to work properly, whereas the tolerances for a lock back are not as critical. The lock back design takes more abuse, has less wear surface between the locking bar and the blade, and is easier and less expensive to manufacture making it the preferred design for a simple pocket knife. Further, the unlocking mechanism of #724 requires a side force applied from a direction perpendicular to the handle, and when the blade unlocks, the user&#39;s finger or thumb is aligned with the sharpened blade portion thereby exposing the user to a potential cut hazard. 
     There are many designs of mechanical locks, most being constructed of many components all interrelating to complicated mechanisms that are susceptible to failure, but none achieve a reliable integrally formed lock for two member tools that are connected about a pivot such as foldable knives, saws, files or foldable ladders. Also, the prior art does not teach or suggest an integral lock for slideably engaging an extension tools in the extended use position that disengages with manual pressure. 
     SUMMARY 
     The present invention relates to a mechanical lock that engages tools securely in the of use position. The term tool herein means any multi-section device that slidably connects, or two member devices that pivotally connects. 
     Extensible tools such as extendable handles, scaffolding legs, and extension ladders benefit from an integral lock to securely engage to sections together securely when in use referred herein as the “extended” position, and when the lock is disengaged, the extensible tool freely slides within itself referred herein as the “compacted” position. Foldable ladders and tools connected by pivot such as knives or saws, the position of use is referred herein as the “open” position, and when the integral locks is released the two member device is foldable into a condensed position referred herein as the “closed” position. 
     As used herein, the terms “integral” and “unitary construction” refers to a construction that does not include any welds, fasteners, or other means for securing separately formed pieces of material to each other, as the lock is one continuous piece. The integral lock is incorporated into devices either by unitary construction being built within the tool component in, or by attachment using traditional fixation means such as through fasteners, pins, or welds. 
     The integral lock consists of a biased locking bar having a pressure pad on one end, and a locking end portion on the other end. Unlocking is performed by applying manual pressure to the locking bar at pressure pad end such that the locking end portion is urged away from the tang notch or lock notch of the other tool component. The locking bar has an effective pivot point located within a supporting arm structure that extends from the locking bar. What is meant by an effective pivot point is that the locking bar flexes at the support arm as if it was pivoting, but without a pivot structure. The support arm may be resiliently biased to increase pressure of the locking end portion using heat treating techniques. 
     The mechanical lock simplifies the manufacturing processes while eliminating the need for additional individual discrete parts. The elegant unitary construction of the mechanical lock is easily manufactured, simple to use, and as durable as the metal from which it is constructed. 
     Depending on manufacturing method and application, the locking mechanism may require an additional step to provide the desired resilient characteristics. For example, if the material is steel or other heat treatable material, the locking mechanism is heat treated after being deformed to the desired resilient position thereby creating a spring biased form without the need of adding a spring component. The desired resiliency force to unlock by applying force to the pressure pad end is achieved through the cut out of the lock, heat treating, materials used, or a combination thereof. 
     The resiliency force may also be modified by changing the thickness or depth of the notch, increasing or decreasing the cross section or the type of material of the support arm component, or altering the relative location of the support arm component as integrally formed between the pressure pad end and the locking end portion. To explain, extending the pressure pad end further from the support arm and locking end portion reduces the amount of force needed to release the locking end portion proportional to the increased leverage. 
     The integral lock benefits from a safety interlock shim feature executed by sliding a shim or spacer underneath the pressure pad end or through the lock bar, thereby preventing accidental release of the lock. The safety interlock shim feature is especially useful on tools such as ladders where redundant locking systems are favored to ensure safety of the user. 
     Further characteristics and advantages of the present invention will become better apparent from the following detailed description of the preferred but not exclusive embodiments of the mechanical locking device for tools of the type with two pivoted components, such as knives, saws, files, foldable ladders, and the like, and tools of the type with multiple sections slidably engages such as scaffolding legs, extension ladders, extendable handles, and the like, according to the invention, illustrated by way of non-limiting example in the accompanying descriptions and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a close up perspective view of the integral lock as unitarily constructed into an extension ladder embodiment. 
         FIG. 2  is a perspective view of the integral lock unitarily constructed into an extension ladder embodiment. 
         FIG. 3  is a perspective view of the integral lock unitarily constructed into a foldable ladder embodiment. 
         FIG. 4  is a side view of the integral lock unitarily constructed into a foldable ladder embodiment. 
         FIG. 5  is a cutaway side view of the integral lock unitarily constructed into the handle of a foldable saw tool embodiment. 
         FIG. 6  is a perspective view of the integral lock unitarily constructed into a single side handle section of a lock back knife embodiment. 
         FIG. 7  is a side view of the handle blank of a one-sided handle embodiment of the folding knife as first depicted as  FIG. 7  in application Ser. No. 12/927,474 filed on Nov. 15, 2010. 
         FIG. 8  is an elevated side view of the one-sided handle embodiment as first depicted as  FIG. 8  in application Ser. No. 12/927,474 filed on Nov. 15, 2010. 
     
    
    
       
     
       
         
           
               
             
               
                   
               
               
                 Reference Table 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                   
                  1. 
                 First Member 
               
               
                   
                  2. 
                 Second Member 
               
               
                   
                  3A. 
                 Double tooth saw 
               
               
                   
                  3B. 
                 Blade 
               
               
                   
                  16. 
                 Tang Portion 
               
               
                   
                  19. 
                 Pivot Structure 
               
               
                   
                  22. 
                 Integral Lock 
               
               
                   
                  22A. 
                 One Side 
               
               
                   
                  23. 
                 Through Fasteners 
               
               
                   
                  23A. 
                 Spacers 
               
               
                   
                  30. 
                 Locking bar 
               
               
                   
                  36. 
                 Locking End Portion 
               
               
                   
                  36A. 
                 Locking Hardware 
               
               
                   
                  38. 
                 Pressure Pad End 
               
               
                   
                  38A 
                 Pressure Pad Hardware 
               
               
                   
                  40. 
                 Support Arm 
               
               
                   
                  44. 
                 Arm Depth 
               
               
                   
                  46. 
                 Tang Notch 
               
               
                   
                  52. 
                 Force 
               
               
                   
                  53. 
                 Direction 
               
               
                   
                 110. 
                 First Section 
               
               
                   
                 120. 
                 Second Section 
               
               
                   
                 125. 
                 Notch 
               
               
                   
                 130. 
                 Extended Position 
               
               
                   
                 136. 
                 Safety Interlock Shim 
               
               
                   
                 201. 
                 Open Position 
               
               
                   
                 205. 
                 Style Cutout 
               
               
                   
                 206. 
                 Ergonomic Grip 
               
               
                   
                   
               
            
           
         
       
     
     DETAILED DESCRIPTION 
     In the embodiments that follow, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other embodiments. 
     As depicted in  FIG. 1  and  FIG. 2 , the extendable and retractable embodiment shown in a close up perspective in  FIG. 1  and in the extended position  130  in  FIG. 2  is depicted as an extension type ladder for illustrative purposes, as the integral lock  22  could be used for an extending leg for scaffolding, or a tubular handle extension for a pruning saw or the like. The integral lock  22  secures the position of the first section  110  relative to the second section  120  without the need for any additional fasteners, welds, or discrete components. However, additional hardware could be added for specific applications or for ascetic enhancement. The outer sections  110  and inner sections  120  slidably engage which can be along a track, a groove, or as shown, a tube within a tube configuration. The embodiment depicted in  FIGS. 1 and 2  illustrate the tube within a tube configuration and the outer sections  110  and inner sections  120  may be constructed from square, round, or rectangular tubing allowing for the first section  110  is formable to include an integral lock  22 , and the second section  120  includes at least one notch  125 . Or alternatively the first section  110  includes at least one notch  125 , and the second section  120  is formable to include an integral lock  22 . 
     The integral lock  22  as used in extendable tools depicted in  FIGS. 1-2 , may be constructed of any suitable material. For the extendable ladder embodiment, the first section  110  and second section  120  are constructed from rectangular tubing, with the second section  120  having an outside dimension less than the inner dimension for the first section  110  as shown in  FIG. 1 . The thicker the square tubing wall the thicker the support arm  40 , which equates to a greater resiliency or spring like characteristic of the locking bar  30 . As an alternative to thicker and heavier tubing, resiliency or positive spring like pressure may be increased as shown in  FIG. 1  by increasing the arm depth  44  of the support arm  40  which allows further biasing of the locking end portion  36 . The support arm  40  may be further enhanced through heat treatment techniques in order to achieve the desired resiliency. The resiliency of the integral lock  22  defines the force required at the pressure pad end  38  to unlock the first section  110  in relation to the second section  120 . 
     The bias of the support arm  40  is desirably strong enough to retain the locking end portion  36  in resistive sliding contact with the second section  120  between notches  125 , and upon the locking end portion  36  aligning with a notch  125  as depicted in  FIG. 1 . Upon the locking end portion  36  engages within the notch  125 , the second section  120  is securely located in relation to the first section  110 . Upon the locking end portion  36  dropping into the notch  125 , the pressure pad end  38  raises slightly in opposition like a teeter totter, and upon the pressure pad end  38  being pushed down, the locking end portion  36  lifts from the notch  125  releasing the second section  120  from the first section  110 . The bias of the support arm  40  is preferably limited such that manual pressure by a user&#39;s thumb or finger is adequate to lift the locking end portion  36  thereby disengaging the second section  120  from the first section  110 . 
     As shown in  FIG. 2 , second section  120  slidably engages within the first section  110 , the second section  120  having notches  125  commensurate with extended location positions  130 . The integral lock  22  formed from the first section  110 , such that the locking end portion  36  engages the notch  125  upon the second section  120  and first section  110  reaching an extended position  130  that aligns the notch  125  with the locking end portion  36 . As discussed above, when extended to the location having the notch  125  aligns with the locking end portion  36  the integral lock  22  securely engages the first section  110  in relative position with the inner portion  120  until released. To release the integral lock  22 , pressure is applied to the pressure pad end  38  which flexes the support arm  40  lifting the locking end portion  36  out of the notch  125 , allowing the second section  120  and first section  110  to freely slide relative to one another. 
     Similar to extendable tools, foldable pivot tools benefit from the integral lock  22  as illustrated by example in  FIGS. 3-6 . The foldable ladder embodiment as shown in  FIGS. 3 and 4  includes a first member  1  and a second member  2  connected by a pivot structure  19 , the pivot structure  19  being constructed as simply as a through pin as shown, or as complicated as an inset bearing. The first member  1  includes a tang portion  16 , the tang portion  16  having at least one tang notch  46  formed to match the shape and size of the locking end portion  36  of the integral lock  22  which is shown as cut out from the second member  2 . As with the extensible tool embodiment shown in  FIGS. 1 and 2 , the integral lock  22  has a locking bar  30  integral with a support arm  40  continuously formed between a locking end portion  36  and a pressure pad end  38  constructed and arranged to lock the first member  1  in relation to the second member  2  when the locking end portion  36  engages the tang notch  46  defining the open position  201 , and unlocks the first member  1  in relation to the second member  2  when force is applied to the pressure pad end  38  urging the locking end portion  36  from the tang notch  46  disengaging the first member  1  to pivot freely in relation to the second member  2 . For further positive securing, a safety interlock shim  136  locates under the pressure pad end  38  such that the locking end portion  36  cannot be urged from the tang notch  46  while the safety interlock shim  136  is in place. The safety interlock shim  136  may be used in any of the embodiments demonstrated in  FIGS. 1-6 . 
     As shown in  FIGS. 5 and 6  are two exemplary embodiments of foldable pivot hand tools benefiting from the integral lock  22  constructed from a flat sheet of metal. As shown in  FIGS. 7 and 8 , the integral lock  22  may be further formed through bending to create an integrally formed spine  50  to increase rigidity, or to increase surface contact areas of the locking end portion  36  or pressure pad end  38  as depicted in  FIG. 8 . 
     The cutaway side view in  FIG. 5  demonstrates the integral lock  22  as used in a fold out saw embodiment. In  FIG. 6  is a perspective view of a foldable knife embodiment with single flat side  22 A formed into the inventive integral lock  22  as cut out from a flat sheet of metal. Both of these embodiments represent a foldable pivot tool configuration using the integral lock  22 , each having two members, a first member  1  “utensil” and second member  2 , “handle”, the first member  1  and second member  2  being connected about a common pivot structure  19 . The first member  1  could be any of a variety of ‘utensils’ to include knives, files, saws, or similar type devices. The second member  2  includes at least one integral lock  22  cut out or punched from a flat sheet of metal, as better depicted in  FIG. 6-8 . Non-locking handle parts or handle inlays constructed of wood, plastic, metal or bone are readily fixated to the second member  2  for desired for aesthetics, ergonomic fit, floatation, or other application specific purposes. 
     In  FIG. 5  the fold out hand saw embodiment is shown in the open position  201  having the integral lock  22  engaged such that the first member  1  is locked in position relative to the second member  2 . As previously mentioned, decorative components are readily attached to the second member  2  and the second member  2  may be specially formed with a style cutout  205  or ergonomic grip  206 . The robust design of the integral lock  22  readily allows embellishments to the second member  2  such as the style cutout  205  and the ergonomic grip  206  without altering the functional characteristics or effectiveness of the integral lock  22 . The fold out saw embodiment includes a first member  1  having a tang portion  16 , the tang portion  16  having at least one tang notch  46  and a pivot structure  19 . Here the first member  1  includes a double tooth saw  3 A that folds up into the second member  2 . The second member  2  is connected by the pivot structure  19  to the first member  1  and includes an integral lock  22  that is formed from the continuous metal of the second member  2 . The pivot structure  19  pivotally mounts the first member  1  to the second member  2  such that when the first member  1  and second member  2  pivot to position allowing the locking end portion  36  to engage the tang notch  46  for the in use or open position  201  as depicted. To release, pressure is applied to the pressure pad end  38  urging the locking end portion  36  out of the tang notch  46 , freeing the first member  1  to rotate in relation to the second member  2 . 
     The integral lock  22  depicted in  FIG. 6  functionally locks and unlocks the in the same manner as the foldable hand saw embodiment shown in  FIG. 5 , and for consistency the same numerics are used to identify the components of the integral lock  22 .  FIG. 6  shows the integral lock  22  from a perspective view to illustrate in three dimensions that the integral lock  22  is cut from one flat side  22 A of sheet metal by simply punching out the pattern of the blank requiring no further forming or bending. Folding or bending over a spine  50  (Shown in  FIGS. 7 and 8 ) increases strength and rigidity, however is not necessary in many smaller hand tool application. The locking bar  30 , support arm  40 , locking end portion  36  and pressure pad end  38  are all unitarily formed from a continuous sheet of metal of the one flat side  22 A. The locking end portion  36  further includes a fixated locking hardware  36 A that as attached to the locking end portion  36  enhances locking capability. 
     As shown in  FIG. 6 , the at least one side  22 A is complimented with fixated hardware including spacers  23 A and through fasteners  23 B that would allow locating for example a non-locking handle side (not shown) and fixating the same to the at least one side  22 A allowing unlimited options in handle configurations as constructed around or adjacent to the second member. Depending on the resiliency of the support arm  40 , significant force  52  may be required at the pressure pad end  38  to lift the locking end portion  36  from the tang notch  46 . To increase the surface are of contact making it easier to apply manual force  52 , pressure pad hardware  38 A is included as fixated adjacent to, on top of, or next to the pressure pad end  38  such that the force  52  to disengage the integral lock  22  is more comfortably applied. The pressure pad end  38  and pressure pad hardware  38 A as shown readily benefits from non-slip texture and finger shape to increase positive feel and secure contact by the user when applying manual force  52  for unlocking. 
     The unlocking of the first member  1  in relation to the second member  2  is performed by applying force  52  at the pressure pad end  38  or at the pressure pad hardware  38 A. For the one-sided embodiment depicted in  FIG. 6 , the narrow surface area of the pressure pad end  38  that could make releasing the integral lock  22  difficult for some users is overcome by the inclusion of the pressure pad hardware  38 A. The pressure pad hardware  38 A as shown is fixated to the side or top of the pressure pad end  38  by through fastener, but may be fixated using any suitable method. 
     The support arm  40  as discussed above provides the effective pivot point for the locking bar  30  and defines the resilient bias of the integral lock  22 . As shown in  FIG. 6 , the robust design of the integral lock  22  allows for the inclusion of hardware such as pressure pad hardware  38 A, locking hardware  36 A, spacers  23 A or through fasteners  23 B as attaching to the second member  2  without materially altering function or changing the performance of the integral lock  22 . 
     As first depicted in  FIGS. 7 and 8  in application Ser. No. 12/927,474 filed on Nov. 15, 2010 now shown for comparative reference in  FIG. 7  having the second member  2  in blank form prior to bending, and  FIG. 8  showing the second member  2  benefiting from a forming 90 degree bend. Both embodiments depicted in  FIGS. 7 and 8  were cut out of a flat sheet of metal and then as  FIG. 8  depicts further formed by bending to form the spine  50  for example. As shown in  FIG. 6 , the integral lock  22  is fully formed without any further forming or bending. To form the second member  2  in  FIG. 6 , a blank is cut out of a flat sheet of metal leaving the integral lock  22  unitarily constructed within the second member  2 . Unlike embodiments shown in  FIG. 8 , there is no further forming with bends after the blank is punched out, thus leaving the integral lock  22  flat as the sheet of metal that the second member  2  was cut from. 
     The inclusion of the spine  50  shown in  FIG. 8  increases rigidity and strength at the locking end portion  38  which is similarly achieved by the inclusion of the locking end hardware  36 A as shown in  FIG. 6 . The pressure pad end  38  as shown in  FIG. 8  benefits from a 90 degree bend thereby increasing the contact area similar to the inclusion of the pressure pad hardware  38 A depicted in  FIG. 6 . The inclusion of the spine  50 , locking hardware  36 A, and pressure pad hardware  36 A are examples of enhancements to the integral lock  22 , but are not necessary to its function. 
     For the embodiments shown in  FIGS. 1-8 , the support arm  40  is cut out of the same continuous sheet of metal as the locking bar  30 , pressure pad end  38 , and the locking end portion  36 . Desired resiliency, locking strength and release pressure are achieved by increasing or decreasing the thickness of the continuous sheet of metal, shape and thickness of the support arm  40 , heat treatment, or combinations of the same. To increase the locking hold of the integral lock  22  for the extensible tool embodiment, the notches  125  are cut deeper to more positively set the locking end portion  36 . For further positive securing, a safety interlock shim  136  as shown in  FIGS. 3 and 4  locates under the pressure pad end  38  such that the locking end portion  36  cannot be urged from the notch  125  while the safety interlock shim  136  is in place. 
     The foregoing description of the preferred embodiments to include extensible devices and pivot tools each incorporate the present invention have been presented for the purpose of providing an illustrative disclosure and enabling description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, as the integral lock can be utilized on both pivot and extensible tools. Many modifications and variations are possible in light of the above teachings. All the details may be replaced with other technically equivalent ones. In practice, the materials used, as well as the shapes and the relative dimensions, may be any according to requirements without thereby abandoning the scope of the protection of the appended claims. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs. It is intended that the scope of the present invention not be limited by this detailed description, but by the claims and the equivalents to the claims appended hereto.