Abstract:
An Auto-Lock Broadhead is disclosed having incorporated a unique, new, fail-safe, self-locking system to eliminate the possibility of blade failure, either upon launching, or upon impact. It is the only current design of its kind in existence.

Description:
BACKGROUND 
     An Auto-Lock broadhead is a mechanical arrow head. This device when affixed to an arrow, which is launched from an archery hunting bow, is designed for the purpose of harvesting game animals. The difference between fixed blade broadheads and mechanical broadheads, is that fixed blades are just that. They are constructed with blades that do not move or open. 
     Mechanical broadheads are designed to flip open their blades to create a much larger wound channel than fixed blades to facilitate a cleaner, quicker dispatching of the prey animal. 
     All mechanical broadheads are supposed to remain closed during launching, to obtain maximum aerodynamic flight, and open to their full cutting potential upon impact. The Auto-Lock broadhead is unique in its design, in that it is the only broadhead that has a fail-safe, self-locking mechanism, which locks it closed on launching and locks it opened on impact. 
     The Auto-Lock broadhead is a completely new design regarding mechanical broadheads. The unique self-locking design features enable it to eliminate the current failure rate problems plaguing the mechanical broadhead industry. Specifics of the self-locking system are described in detail in the description section. 
     BRIEF SUMMARY OF INVENTION 
     Current mechanical broadhead designs do not have a positive reliability factor. Additionally, current mechanical broadhead designs have a tendency to open in flight, causing erratic arrow flight, have a tendency to allow the blades to collapse on impact, and have no positive locking system to insure reliability. Additionally, current mechanical broadhead designs rely totally on the forward inertia of the arrow to maintain full deployment of the blades and a majority use an un-reliable rubber band to keep them closed during launching. 
     The presently disclosed Auto-Lock broadhead has increased the reliability factor exponentially by: (a) including a blade with a locking notch that positively enables the blades to lock open; (b) providing a ferrule pin for the blade notches to lock onto, once fully deployed; and (c) incorporating a coil spring that keeps the intrinsically designed notches in the front of the blade forced forward, inside the ferrule, during launching, to eliminate the possibility of the blades prematurely opening during launching. 
     An objective of the disclosed Auto-Lock broadhead is to improve the performance, or non-performance of the mechanical broadheads currently available. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  shows a side view of an embodiment of the disclosed Auto-Lock in its locked closed state.  FIG. 1B  shows a side view of an embodiment of the disclosed Auto-Lock in its locked opened state.  FIGS. 1A and 1B  each include an illustration of the positioning of a blade  7  inside ferrule  4 . As can be seen in  FIG. 1A , blades  7  are held in the forward closed position by the coil spring  3  with the forward notch  8  in the blades locked inside the ferrule  4 . As can be seen in  FIG. 1B , blades  7  are locked in the fully deployed, open position by the notches  8  in the underside of the blades resting on the pin  10  in the ferrule  4 . 
         FIG. 2A-2C  illustrate an exemplary blade  7  having curved inner surfaces that produce the cam action required to open the blades, a locking notch which interlocks with the ferrule pin to lock them open, and two small notches in the front of the blade which slide under the ferrule to lock them closed.  FIGS. 2A and 2B  show side views of the exemplary blade  7  and  FIG. 2C  shows an end view of the blade  7 , with height and thickness illustrated. 
         FIGS. 3A and 3B  show side views of an exemplary aluminum ferrule  4 , herein sometimes referred to as a “housing,” which the other components of the broadhead will be affixed to. 
         FIG. 4A  shows a top view of an exemplary dowel pin  10  and  4 B shows a side view of the exemplary dowel pin  10  shown in  FIG. 4A . As can be seen in  FIGS. 1A and 1B , a dowel pin  10  may be driven into the ferrule  4 , upon which the blades  7  lock onto, which locks them in the open position. 
         FIG. 5A  shows a top view of an exemplary hex socket screw  14  and  FIG. 5B  shows a side view of the exemplary hex socket screw  14  shown in  FIG. 5A . As can be seen in  FIGS. 1A and 1B , hex socket screw  14  may attached blades  7  to the piston  2 . 
         FIG. 6A  shows a top view of an exemplary stainless steel spring  3  and  FIG. 6B  shows a side view of the exemplary stainless steel spring  3  shown in  FIG. 6A . As can be seen in  FIGS. 1A and 1B , stainless steel spring  3  surrounds the piston  2  to cause forward pressure to lock the blades  7  closed inside the ferrule  4  while in flight. 
         FIG. 7A  shows a top view of an exemplary hardened steel, threaded tip  6  and  FIG. 7B  shows a side view of the exemplary hardened steel, threaded tip  6  shown in  FIG. 7A . As shown in  FIGS. 1A and 1B , threaded tip  6  may screw onto the leading end of the piston  2  to provide penetration. 
         FIG. 8  shows a side view of an exemplary piston  2 , to which both blades  7  affix and to which the hardened steel tip  6  is screwed onto. 
     
    
    
     DETAILED DESCRIPTION OF INVENTION 
     The Auto-Lock Broadhead&#39;s unique design features have eliminated that part of the equation that refers to the failure rate of other mechanical broadheads. 
     LOCKING THE BLADES OPENED: The blades  7 , which are attached to the piston  2  and tip  6 , are forced rearward to the fully opened position, by the inertia of the piston  2  being forced rearward, upon impact. The blades  7  are designed with a curved inner surface, which acts as a cam, causing them to open fully, and simultaneously. The blades  7  lock onto a pin  10  installed into the ferrule  4  or main body of the broadhead, when fully deployed. This function prevents them from moving forward and thus having the ability to close or fail to remain opened. (This is a major flaw in all other mechanical broadheads, the ability to remain locked opened) 
     LOCKING THE BLADES CLOSED: Specially designed notches  8  in the front of the blades  7  lock inside of the aluminum body or ferrule  4 . This is accomplished by the spring tension of 0.09 lbs., which surrounds the piston  2 , forcing it and the blades  7  forward into the locked closed position. This locking closed function precludes any possibility of the blades  7  opening prematurely during lunching of the arrow, which would cause the arrow to have erratic flight. (Another major flaw in most other mechanical broadheads, as the majority of them rely on a rubber band to keep them closed.) In contrast to other known devices, the disclosed Auto-Lock Broadhead locks in both closed and opened positions. No other current broadhead design incorporates a self-locking system of any kind. 
     An exemplary listing of Components, Materials, and Dimensions that may be used to produce Auto-Lock Broadheads in accordance with the subject disclosure are as follows: 
     One Aluminum body (ferrule): machined from—7075-T6 Aluminum, 0.300″ in diameter, 1.950″ in length. An exemplary aluminum ferrule  4  is illustrated in  FIGS. 3A and 3B , along with possible dimensions. 
     One Sliding shaft, (piston), machined from: 7075-T6 Aluminum, 0.195″ in diameter, overall length is 0.984″. An exemplary piston  2  is shown in  FIG. 8 . 
     Two Cutting Blades, stamped from, material: 420 stainless steel (0.036) thickness, length is 1.595″, each being identical to the other. An exemplary cutting blade  7  is illustrated in  FIGS. 2A-2C . 
     One hardened steel, screw on tip, which is threaded onto the leading end of the piston, is machined from 316 steel, hardened to 54C Rockwell. The outside diameter is 0.300″. The total length is 0.690″. The internal thread is 12×28. An example tip  6  is illustrated in  FIGS. 7A-7B . 
     An Example Manufacturing Processes for the Auto-Lock Broadhead is as Follows. 
     The aluminum parts, (ferrule and piston) are mass produced on a Swiss type, multi spindle, automatic feed, CNC controlled, turret lathe. They are machined from 7075 grade aluminum round stock. They are then anodized to produce a black color and add hardening to the ferule and piston. 
     The blades are produced by the stamped metal process. The raw material is 420 annealed stainless steel sheet which is die stamped into their finished shape. The blades are then precipitation hardened and then sharpened. The finish color is natural. 
     The remaining parts are shelf items obtained from various hardware manufacturers. 
     Total weight of assembled unit: 100 grains, Total deployed cutting surface 1.8″.