Abstract:
A tool is disclosed, for inserting a multi-turn spiral lock, received by a groove of a piston assembly The tool includes a handle, for transmitting manual torque forces, to enter a spiral, grooved head, or a profiled fitting, a wire lock ring The spiral, grooved head, is manufactured, with a ½ turn medium-pitched, helical groove. This permits the ½ spire, after being assembled, to be easily pushed, and transferred, to a piston groove. Also, a wire lock end, equipped with a controlled sliding sleeve, allows the ring to be located on the tool, prior to assembly. This allows for an easy bore insertion to snap the wire lock into the bore groove.

Description:
TECHNICAL FIELD  
         [0001]    This invention relates to an assembly tool used in an internal motor engine, a compressor or the like. More particularly, it is used for the installation of a spiral lock or wire lock ring, allowing the retention of the piston wrist pin into the piston head, cross bore.  
         BACKGROUND  
         [0002]    1. Prior Art  
           [0003]    The subject invention consists of a tool used to install a fastener on a work piece and the method of installing such a fastener. More specifically, this invention consists of a hand tool used to assemble a spiral lock or ring lock insert, thus retaining a wrist pin that holds the connection rod. Such a rod is actually being connected to a piston link and its mechanism. There is a further appreciation in that such an invention has broader applications. This is both a useful, simple tool and a time saver, for many applications where internal insertion through a grooved bore of helical or wires lock ring is required.  
           [0004]    2. PRIOR ART  
           [0005]    The assembly problem of a wrist pin retainer has been addressed for more than a century. The trend, however, has changed in the last few decades, as the retaining ring has become more popular, and the wire ring and helical lock ring have become standard in the industry, for medium and small engines. The manufacturer provides, and a patent search has shown, there are several systems with tool kits, for the removal and insertion, of such rings, but they require enormous pressure. This pressure presents a risk of scoring the surface, and also produces small metal scraps, which is very undesirable and could lead to damage to the engine.  
           [0006]    The following is a list of Patent search references and several wrist pins were reviewed.  
           [0007]    U.S. Pat. No. 4,445,800 Walker 1984  
           [0008]    U.S. Pat. No. 4,640,641 Edelmayer 1987  
           [0009]    U.S. Pat. No. 5,009,124 Baurepaire etal 1991  
           [0010]    These three patents are relative to wrist pin manufacturer innovation only. They are not pertinent to the present applied patent.  
           [0011]    U.S. Pat. No. 5,076,149 Everts 1991 shows a different way to retain the wrist pin, a way of deforming, in a controlled fashion, the ends of the wrist pins, making it permanent. This is also not pertinent to this present applied patent.  
           [0012]    U.S. Pat. No. 5,289,758 Avco Lycoming Company 1994. This patent shows, on FIG. 2, another unique way to anchor a wrist pin that is fixed permanently to the piston head and is retained by two rings and two tapered plugs that are forced through a taper bore. This is not pertinent to this present applied patent.  
           [0013]    U.S. Pat. No. 5,802,694 Myles 1998 shows a tool, which is similar to the proposed present patent. However, it is concerned with the removal of a spiral lock ring. Such an invention is a simple, economical, and versatile apparatus for removing the spiral lock from a piston assembly. This invention also provides a means of installing such a ring in a similar internal groove of a bore. This is quite different, and for this reason, it does not provide wire lock ring installation, such as a common, economical, simple tool would.  
         BRIEF DESCRIPTION OF THE INVENTION  
         [0014]    The insertion of a spiral lock ring into a grooved bore, to establish a wrist pin abutment, is a difficult task. The spiral lock rings are made of hard spring steel, without much compressibility to decrease the outside diameter which is generally 0.060″ larger than the bore. Also, the fact that such a ring is made of a rectangular section, and has at least three spires, makes it particularly incompressible. To enter such a ring into the piston cross bore, being a transitory conical bore, which has a greater diameter at one end (the top) than the ring with a smaller diameter, at the other end than the piston cross bore, so that the ring is pressed as it is transferred up to the internal groove, requires a great amount of pressure. This extreme pressure can contribute to scratching the aluminum (the bottom) bore area, with the accumulation of many scrap pieces, not desirable for an engine.  
           [0015]    The present invention will provide a remedy with it&#39;s manual, combination for installing an internal spiral lock ring at one end, and a wire lock ring at the other end, into a grooved cross bore of a piston head. It is simple and easy to operate and can be handled without the fear of breaking a fingernail or cutting off the fingertip. The spiral ring head has a combination of details, which have been studied experimentally, and compound each other. This allows a smooth, progressive installation with a normal amount of effort. It consists of a spiral groove of a specific angle, size and length.  
           [0016]    A back slanting recess with a diameter allows a good grip for manually handling the grooved head and the knurl handle.  
           [0017]    The wire lock ring has a means to safely install the ring in front of the head. It also retains the ring, which allows an easy bore transfer into the groove, with a simple sleeve cylinder around the inserting head. Because of its simplicity, and the fact that it has no intricate mechanism, such as a spring pivot, with its simple form, requires little dexterity and is a valuable, economical compact tool, with a double use for either spiral or wire lock rings. The spiral, lock and wire, lock rings, vary in size, especially for motors from ½″ diameter to 1½″ diameter. The detailed description, of this invention, starting on page 6, applies to lock ring diameters ranging from ⅜″ in diameter to 1½″ diameter. 
       
    
    
     BRIEF DRAWINGS&#39; DESCRIPTION  
       [0018]    Drawing #1 shows the basic concept of the tool function for the spiral lock ring insert.  
         [0019]    [0019]FIG. 1- 1  shows a front view of a spiral lock ring.  
         [0020]    [0020]FIG. 1- 2  shows the right hand side of the ring.  
         [0021]    [0021]FIG. 1- 3  shows a perspective view of the spiral lock manually opened and ready, for insertion.  
         [0022]    [0022]FIG. 1- 4  shows the deflection of the first spire of the multi-spired ring  
         [0023]    [0023]FIG. 1- 5  shows a view of the center with a full 360° spire deflection.  
         [0024]    [0024]FIG. 1- 6  shows a side elevation of the grooved, spiral, tools left end.  
         [0025]    [0025]FIG. 1- 7  shows an enlargement of a partial section of the relative position  9   a  to the spiral groove on the fitted spring section.  
         [0026]    Drawing #2 shows the basic insertion tool.  
         [0027]    [0027]FIG. 2- 1  shows a cross section of a piston head at the cross bore level.  
         [0028]    [0028]FIG. 2- 2  shows a perspective of a three-turn spiral lock ring.  
         [0029]    [0029]FIG. 2- 3  shows a profile elevation of the ring.  
         [0030]    [0030]FIG. 2- 4  shows how a thin, low, angular edge separates the first loop from the others.  
         [0031]    [0031]FIG. 2- 5  shows a perspective of the wire lock ring.  
         [0032]    [0032]FIG. 2- 6  shows the entire double-end insertion tool.  
         [0033]    [0033]FIG. 2- 7  shows a left-handed side view of the spiral lock installed on the tool head.  
         [0034]    [0034]FIG. 2- 8  shows a front view of the spiral lock inserted into the grooved head tool.  
         [0035]    [0035]FIG. 2- 9  shows the right end view of the spiral lock with the inserted grooved-head tool.  
         [0036]    [0036]FIG. 2- 10  shows a vertical wire lock ring profile.  
         [0037]    Drawing #3 shows the spiral lock installation, from the top to the bottom.  
         [0038]    [0038]FIG. 3- 1  shows a section of the piston cross bore and the groove.  
         [0039]    [0039]FIG. 3- 2  shows the spiral lock ready to be assembled.  
         [0040]    [0040]FIG. 3- 3  shows the grooved, spiral tool of the left-hand head.  
         [0041]    [0041]FIG. 3- 4  shows the spiral assembly at the tools left hand head.  
         [0042]    [0042]FIG. 3- 5  shows a section of the cross bore and the angular tool ready to be inserted.  
         [0043]    [0043]FIG. 3- 6  shows a left end view of the tool and the first spire of the spiral lock.  
         [0044]    [0044]FIG. 3- 7  shows the first half of the spire, of the spiral lock, ready to enter the groove.  
         [0045]    [0045]FIG. 3- 8  shows a view of the right-handed section of the tool and CCW directional arrow.  
         [0046]    [0046]FIG. 3- 9  shows the spiral lock installed.  
         [0047]    [0047]FIG. 3- 10  shows the tool retracted from the cross bore.  
         [0048]    Drawing #4 shows the tool end, which is used to install the wire lock ring.  
         [0049]    [0049]FIG. 4- 1  shows a front view of the ring.  
         [0050]    [0050]FIG. 4- 2  shows the profile of the simple wire lock assembly of the RH end tool.  
         [0051]    [0051]FIG. 4- 3  shows a profile of the wire ring.  
         [0052]    [0052]FIG. 4- 4  shows how the ring is inserted.  
         [0053]    [0053]FIG. 4- 5  shows a cross-section of the wire lock retainer slider, worked on the end shaft of the tool.  
         [0054]    [0054]FIG. 4- 6  shows an improved wire ring and the top ½ view of the assembly tool.  
         [0055]    [0055]FIG. 4- 7  shows the right-hand view of the tool end with its slider.  
         [0056]    [0056]FIG. 4- 8  shows the front view of the compressed wire lock.  
         [0057]    [0057]FIG. 4- 9  shows a wire lock rings side view projection.  
         [0058]    [0058]FIG. 4- 10  shows a left hand cross section of the tool pushing the wire lock ring into the retainer piston bore groove. 
     
    
     DETAILED DESCRIPTION  
       [0059]    DRAWING 1 shows the basic system and its components.  
         [0060]    [0060]FIG. 1- 1  shows a front view of a retaining ring  1  made especially for a strong; shear load capacity called a “spiral lock ring”. These rings are made of heat-treated spring carbon, steel or  17 - 7  stainless steel as standard items. They can also be customized by using other exotic materials. These rings are made of flat springs, having a rectangular section, which is wound flat. The first and last ½ loops are terminated by an inside recessed notch  2  &amp;  2 A. The external half loop offers greater flexibility and compressibility than the center ones and is a major factor in helping a distortion, necessary to enter the bore.  
         [0061]    [0061]FIG. 1- 2  shows the right-hand side elevation of the stack of spires  3  which are pre-stressed and pressing against each other. Such a component has an entity consisting of a rigid, cylindrical loop, compared to the simple thickness of a retaining ring. The loop structure makes it very difficult to change the shape of the loop, as the need arises, to try to reduce the diameter, allowing insertion on a grooved bore. This requires a reduction in the diameter of nearly {fraction (1/10)} of an inch prior to being inserted and released into the groove. High production shows a method of passing the helical rings through a cone, aligning them with the bore, and using very high pressure from a piston tool, thus distorting the shape and forcing it into the bore, which is aluminum. Such methods leave a lot to be desired, because the potential of permanently stress damaging the spiral lock ring. It leaves bore scratches and loose scrap residue, which are dangerous to the engine.  
         [0062]    [0062]FIG. 1- 3  shows the spires  5  &amp;  6  with only ½ turn, having an open free end that can easily be deflected as a cantilever beam. The spire  4  is a full turn.  
         [0063]    [0063]FIG. 1- 4  shows the effect of squeezing, with a force F 1 , the first spire from  6  to  6   a  deflects it, thus helping to reduce the diameter of the first spire.  
         [0064]    [0064]FIG. 1- 5  shows the center spire with a full turn loop, requiring more pressure force F 2  to deflect it, see the front of  4   a  &amp;  4   b.  This egg shaped distortion does not help in reducing the diameter but the spire loops, being a part of a multi-helical spire, reacts on each other, elongating the spiral length. Thus enabling the reduction of the outside diameter of the spiral lock.  
         [0065]    [0065]FIG. 1- 6  shows how the last spire  5 , FIG. 1- 3  is inserted on a path shown by arrow  9   a.  The guidance of the spiral lock through the spiral groove  9 , which is cut into the front of the shank,  7 , transfers the spiral lock onto the tool. The pitch of the grooved spiral is large enough to spray the spire and allow the pressure to cause an overall elongation. This consequentially produces a diameter reduction, as the spire enters the bore. In front of the shank, a protruding, smaller diameter shank  11  helps support the ring on its inner diameter. Behind the head  7 , a smaller diameter shank links the head to the handle of the tool.  
         [0066]    [0066]FIG. 1- 7  shows a magnified detail of a section of the ring fitting inside the slot  9 . A gap  12  between the bottom of the groove and the inner ring allows a space for the reduction of the diameter of the outside ring. Also, a gap  13  between the width  9   b  of the groove and the spire&#39;s thickness,  3   a,  is set for optimum freedom of the helical ring spires distortion.  
         [0067]    DRAWING 2 shows details of the insertion tool and its usage.  
         [0068]    [0068]FIG. 2- 1  shows a cross-section of a piston head  14  and its cross bore  15  &amp;  16 , where a spiral lock ring  3   b  has already been installed on the left side, and where there is a machined groove  15   a  and a wrist pin  16   a  which is already installed.  
         [0069]    [0069]FIG. 2- 2  shows a perspective of the spiral lock ring  17 .  
         [0070]    [0070]FIG. 2- 3  shows an elevated profile of the ring  17  in line with the bore  15 , FIG. 2- 1 .  
         [0071]    [0071]FIG. 2- 4  shows the last ½ spire loop  18  has been separated and deflected from the other spires with a sharp tool, such as a sharp edged screwdriver  19  or a strong fingernail. The amount of force needed to flex these spires is relatively easy to overcome on this cantilevers half loop.  
         [0072]    [0072]FIG. 2- 5  shows a perspective of a wire lock ring  20  with an open gap  21 .  
         [0073]    [0073]FIG. 2- 6  shows the double functioning insertion tool  26 . One function is for the spiral lock ring on the left side and the other is for the wire lock ring on the right side. Considering the great number of lock rings used, the versatility of such a tool is beneficial. However, a single head tool is also available as the need or preference arises.  
         [0074]    The left side, the head  7  has a spiral groove  9 . Such a groove is made on the cylindrical head, with a pitch of around 0.300″, for a full turn, extending only approximately 0.400″ in length. In front of the head  7  and protruding on the outer extremity is a smaller concentric, diameter shank  11 . This supports the spiral rings&#39; inside diameter, which allows the ring to enter and fit the bore  15 , as it is compacted and carries the ½ loop into the groove  15   a , FIG. 21. On the right side, a head  24  supports the wire ring and also has a smaller, protruding shank diameter  23 . The remainder of the tool consists of concentric shank connections  22  &amp;  22   a  on the left side and  22   b  on the right side. The knurled center mandrel  26   a  is the guiding handle.  
         [0075]    [0075]FIG. 2- 7  shows a left side elevated view of the head  7  with the spiral lock ring  3  installed. The first spire  6  lies outside of the tool&#39;s groove nearly ⅓ of a turn. The other spires are being stored, some behind and some partially in the groove  9  and the remaining are behind the head  7  on the shank  22 .  
         [0076]    [0076]FIG. 2- 8  shows the front face of the tool with diameters of head  7  &amp; protruding shank  11  The spirals  17  first loop  6  assembly is resting on the tools recessed shank&#39;s  11  outside diameter.  
         [0077]    [0077]FIG. 2- 9  shows the right hand view of the front view of the tool FIG. 2- 8  and the spiral  3  assembled in the groove,  9 , and the spiral lying on shank  22 .  
         [0078]    [0078]FIG. 2- 10  shows a wire lock ring  20  with its open gap profile  21 .  
         [0079]    DRAWING 3 shows the function of the spiral, lock, ring and how it is inserted into the piston cross bore groove.  
         [0080]    [0080]FIG. 3- 1  shows a section of a piston head  14  the bore  15  &amp; the groove  15   a  before the spiral lock ring is to be inserted.  
         [0081]    [0081]FIG. 3- 2  shows how the last spires of the ring  3  being separated from the others and assembled into the spiral groove  9  FIG. 3- 3 , though the curved arrow  9   a  showing the direction of the feeding path.  
         [0082]    [0082]FIG. 3- 3  shows the tool  26  as the spiral lock ring is being held still, the last spire  5  is entered into the helical groove  9  entrance, see path arrow  9   a.  Then the tool is being rotated clock-wise, relative to the rear of the tool area  27 . The spiral lock ring is inserted and threaded through the groove  9  toward the shank  22 .  
         [0083]    [0083]FIG. 3- 4  shows the ring installed on the tool head  7  with the first loop  6  protruding out of the groove approximately one half turn.  
         [0084]    [0084]FIG. 3- 5  shows the unusual insertion procedure as the tool&#39;s  26  front head center on axis  26   b  which is set at an angle from the bore axis  16   a.  The front spire  6  is partially entered, on an angle, into the bore, and is compressed to allow the tool to be rotated along the arc  14   a.  The compressed spire, fitting the bores diameter, is then pushed into the bore to insert the first loop  6  into the groove  15   a,  which is sensed by the spire snapping into the groove. Also shown is shank,  22 ,  22   a  and the knurl handle,  26   a.    
         [0085]    [0085]FIG. 3- 6  shows the front left view, looking through the bore  15  at the first loop  6  of the spiral  3  being installed.  
         [0086]    [0086]FIG. 3- 7  shows the insertion of the remaining spires as head  7  is inserted into bore  15  and the spiral lock  3  and the first spire  6  is snapped into groove  15   a.  Then the tool handle  26   a  connected to the head by shank  22  &amp;  22   a  is rotated counter clock-wise. This is smoothly feeding all remaining spires in a progressive way due to two principles.  
         [0087]    1. The groove  9  low-pitched angle provides a mechanical force multiplier.  
         [0088]    2. The spires of the spiral lock are spread due to the grooved shape. This will open wide the spiral lock, which allows easier flexibility and contributes to reducing the outside diameter of the ring.  
         [0089]    [0089]FIG. 3- 8  shows the cross-section of the right side of the insertion tool with the arrow showing the direction for the rotation of the handle of the tool  26   a.    
         [0090]    [0090]FIG. 3- 9  shows the entire spiral lock ring  3  in the bore groove  15   a.    
         [0091]    [0091]FIG. 3- 10  shows the tool  26  being removed from the bore  15 , FIG. 3- 9 .  
         [0092]    DRAWING 4 shows the function as to how the wire lock ring is inserted into the groove of the cross bore with a hand tool.  
         [0093]    [0093]FIG. 4- 1  shows a front view of the wire lock ring  20  with an open gap  21 .  
         [0094]    [0094]FIG. 4- 2  shows a detailed view, of the right hand profile of the wire lock insertion tool  26 , knurl handle  26   a  connecting shank diameter  22   b  to the head diameter  24 , ring holder&#39;s recessed diameter  23 .  
         [0095]    [0095]FIG. 4- 3  shows the profile of the wire lock ring  20  with the location of the gap  21 .  
         [0096]    [0096]FIG. 4- 4  shows the ring  20  being held on the tool end  23  and being manually compressed, arrow  20   a  against the bottom corner of the bore  15  of the piston head  4 .The tool  26  is sufficiently inclined to enter through the edge of the bore. The gap  21  is being set midway between the top and the bottom of the ring to compress the gap, with ease. The tool is then rotated along the arc arrow  37 , so that it can be lined up with the bore. It is then pushed inward, entering the bore until the compressed wire lock spring pops up in the groove. Such action requires dexterity and practice, yet remains a very simple way to assemble the wire lock ring.  
         [0097]    [0097]FIG. 4- 5  shows the shank  30 , integral and concentric to the handle  26   a.  The outside diameter of shank  30  is sized to insure the capability of sliding it into the bore  15 , FIG. 4- 10 . At the right hand of shank  30  extremity, a protruding shank  23  fits into the internal diameter of the ring  20  FIG. 41. It also contains a finger  28  that has a thickness equal to the gap between shank  30  outside diameter and the inside diameter of sleeve  29 . This finger&#39;s outer face has a tangential curve of the diameter of shank  30 . This finger also protrudes {fraction (3/32)} to ⅛ further than plane  23   a.    
         [0098]    [0098]FIG. 4- 6  shows a partial top view of the tool&#39;s right hand and the slide  29 , equipped with an integral, larger, knurled ring  29   a  to allow manual positioning, either forward, backward or rotated in a radially locked position  35   b.  It also shows a set of two cutout notches  33  and  34  diametrically opposite on the sleeve. The slider  29  has two notches  33  and  34  that are cut through the sleeve. This allows a nosed finger pliers to insert the ring compressed in the gap  23   b . The finger  28  allows orientation of the assembly positioning of the gap  21 .  
         [0099]    [0099]FIG. 4- 7  shows a right hand front view of the FIG. 4- 5 , notches  33 ,  34  and finger  28 .  
         [0100]    [0100]FIG. 4- 8  shows the wire lock ring  20  being compressed by a tool acting along the arrow  20   b - 20   c  through the notches  33  &amp;  34  in FIG. 4- 7 .  
         [0101]    [0101]FIG. 4- 9  shows a profile of the ring  20 .  
         [0102]    [0102]FIG. 4- 10  shows the shank  30  after being rotated and unlatched from groove  35   b  FIG. 46. This allows the sleeve  29  to be retracted from the shank&#39;s  30  right end to allow it to penetrate bore  15  and transfers the wire lock ring into groove  15   a  of piston head  14 .