Patent Abstract:
An improved dove tail sight attachment system utilizing a displaceable spherical element to engage a mating hemispherical socket formed along the edge of a dove tail seat on a pistol slide.

Full Description:
FIELD OF THE INVENTION 
     The present invention relates to improved mounting mechanisms for gun sights for small arms which provides for simple and easy replacement. 
     BACKGROUND OF THE INVENTION 
     Conventional gun sight attachments in the form of “dove tail” joints are generally employed in semiautomatic pistols and other small arms. Dove tail joints are usually machined in the pistol slide transverse to the gun axis, providing clamping of the sight in vertical direction with the sight prevented from lateral and transverse movement by the contact of the dove tail walls. This arrangement, while providing a solid coupling between the pistol slide and the annexed sight, is expensive because of the required close tolerances. Furthermore, such dove tails require special tools to assemble and disassemble the sights. Should the machined tolerances be inadequate, the shocks and vibrations of shooting inevitably will lead to the loosening and possible failure of attachment. 
     It is the object of the present invention to provide a gun sight attachment mechanism which makes the sight simple to assemble with and to disassemble from the pistol, with no special tools or skills required. The new mechanism is very simple, inexpensive, and permits alternative materials such as plastics to be employed for the gun sights. The new mechanism uses detent balls which lockingly register with sockets formed in the slide when engaged by a sliding lock pin. Detachment is achieved by removal of the lock pin. 
     For a more complete understanding of the present invention and its attendant advantages, reference should be made to the drawings in conjunction with the detailed description of the invention. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial perspective view of the front portion of a pistol slide having a front sight dovetail slot formed therein; 
         FIG. 2  is a perspective view of a front sight bar having hollow passages formed therein to receive a locking pin and spherical detents for mounting the front sight to the slide; 
         FIG. 3  is a perspective view of the front sight in the slide prior to insertion of the locking pin; 
         FIG. 4  is a cross-sectional view taken along line  4 - 4  of  FIG. 3 ; 
         FIG. 5  is a cross-sectional view taken along line  5 - 5  of  FIG. 3 ; 
         FIG. 6  is a perspective view of a rear sight having the detent lock of the invention adapted for mounting a rear sight on a multi-notched rear portion of a pistol slide; 
         FIG. 7  is a cross-sectional view taken along line  7 - 7  of  FIG. 6 ; 
         FIG. 8  is a top plan view of the rear sight of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The gun sight mount of the invention includes a dove tail seat  10  formed on the front end of a pistol slide  11  provided with two lateral sockets  12 ,  13  machined in the shape of half cylinders to engage and retain the two steel detent balls  14 ,  15 , and a back rest surface  16 . A front bar sight  17  includes a transverse, cylindrical ball retention aperture  18 , a longitudinal, axial, cylindrical channel  19  for reception of a locking pin  20  (solid pin or spring pin) and a rear access aperture  21  for insertion of a punch or a like simple tool for engaging and expelling the locking pin  20 . The steel detent balls  14 ,  15  when engaged in their respective sockets  12 ,  13  secure the front sight bar to the slide by a detent action. 
     In accordance with the principles of the invention, the special dove tail seat  10 , though somewhat similar in shape to a conventional dove tail groove, does not require tight machining tolerances. The retaining of the gun sight  17  in place is not provided by the friction generated by the dimensional interference between conventional dove tail groove and sight, but rather by the ball detents  14 , 15  engaging both in the sight  17  and in the dove tail seat. The sight  17 , with the two detent balls inside in the ball retention aperture  18 , is slidingly inserted in the dove tail seat  10  until it stops against the back rest surface  16 . At this point, the sight  17 , with the sockets  12 ,  13  perfectly aligned with the ball retention aperture  18 , is ready to be secured in place by the insertion of the locking pin  20  in the longitudinal channel  19  and the consequent camming engagement with balls  14 ,  15  to cause a lateral shift of the balls  14 ,  15  into the sockets  12 ,  13  ( FIG. 3 ). Importantly, the sight  17  is kept firmly secured, with no play or looseness, by the locking pin  20  engaging the steel balls  14 ,  15 , as well as the bottom surface  9  of the dove tail seat  10  and the sight  17 . Alternatively, if a spring pin rather than a solid pin is employed as the locking pin  20 , the elastic compression of the spring will contribute to the locking of the sight to the slide. Escape of the locking pin, under the impact of the slide against the frame, is prevented by the rear access aperture  21  being of smaller diameter than that of longitudinal channel  19 . Disassembly is obtained by expelling the locking pin  20  from the channel  19  by a punch or similar tool inserted in the access aperture  21  permitting the detent balls  14 ,  15  to retract from the sockets  12 ,  13  into the channel  19  so that the unlocked sight bar  17  may be slid forwardly out of the dove tail slot  10 . 
     The advantages of the new front sight mounting mechanism include easy assembly and replacement of the sight without special skills or special tools, a hammer and punch being the only tools needed. Given the innovative mechanical retaining system, free of previously required tight tolerances and previously required related hard compression and stress of the two coupled parts (sight and dove tail), alternative comparative inexpensive materials for the sights, such as plastics, may be employed. Moreover, an assortment of sights, providing any desired different settings of the line of sight in windage and elevation, may be provided at low cost. 
     The principles of the invention may be adapted to usage in mounting a rear sight  30  having U-shaped sighting notch  29  and dovetail base  28  adapted to mate with transverse notch  27 . With reference to  FIGS. 6-8 , a traditional transverse dove tail rear sight  30  is modified by machining a series of half-notches or sockets  31 - 35  each capable to receive a steel detent ball  36  inside the profile of the sight ( FIG. 6 , position  1 ). An equal number of half-notches or sockets  41 - 45  in the shape of hemispherical cavities are machined in the sight seat  38 , along the back edge  39  of the dove tail. The sockets  41 - 45  are differently spaced than the notches  31 - 35  in the sight. They are machined with a different pitch as shown in the top view of  FIG. 8 . Specifically, central notch  33  of the sight is placed on the central axis of the sight while the central notch  43  of the seat is placed on the mid plane of the gun. The coincident location of notches  33 ,  43  is shown in  FIG. 8 , and represents a perfectly centered position of the sight with respect to the gun axis. 
     The different location of the notch  42  on the sight seat with respect to the corresponding notch  32  on the sight shifts the rear sight slightly to the right, when the two notches  32 ,  42  are assembled in registry. Similarly, notch  41 , provides an increased shift to the right. Notch positions  44  and  45  are symmetrical with those of notches  42 ,  41  and provide for corresponding shifts to the left. In the illustrated mounting, there are five different selectable windage settings: two on the right, two on the left, plus the central “zero” position; however, it will be understood that variations may be obtained through different cylindrical arrangements of ball/notch diameter and position as may be desired. The rear sight can be kept firmly in place by insertion of a locking (or spring) pin  50  into transverse channel  52 , to cam the steel ball  36  out from position  1  to position  2  ( FIG. 7 ). The “multi notch” rear sight brings in the whole advantage of the steel ball detent system such as easy assembly/replacement (plus adjustability) and inexpensive construction due to the tight tolerance relief. 
     It should be understood, of course, that the specific form of the invention herein illustrated and described is intended to be representative only, as certain changes may be made therein without departing from the clear teachings of the disclosure. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention.

Technology Classification (CPC): 5