Abstract:
An adjustable torque limiter that can be coupled between a high speed driver and the socket that rotates a mechanical fastener. When a preset torque level is reached, the torque limiter disengages the rotational drive force from the bit. The adjustability of the torque limitation is accomplished by varying the amount of spring force by which a thrust plate (coupled to the high speed driver) is forced against a set of steel balls residing in slots of a radial torque plate and in a set of paths formed in a concavity of an upper torque body (coupled to the driven socket engaging stud). When a certain preset torque is transmitted from the driver to the socket, the steel balls traverse outward along the separate arced ramp radial paths therein the upper torque body until the balls enter an annular race that allows the thrust plate to go into a disengaged or free wheel mode from the upper torque body.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a extremely sturdy and versatile torque limiting device adapted to be used in conjunction with any type of driver tool utilized for the rotational tightening of mechanical fasteners. More particularly, to an accurate torque limiting device designed to be used in a production environment where the driver it is matingly coupled to is operated pneumatically, hydraulicly or electrically at a high speed. 
     The proper operation of many mechanical components is, to a large degree, dictated by how the parts are assembled. Over tightening of mechanical fasteners can lead to cracked bodies, stretched and weakened bolts, stripped threads, smaller clearance tolerances, and a plethora of other maladies that can seriously affect the operation of the item in question. Similarly, under tightening of mechanical fasteners can have its own, different but potentially disastrous results. For this reason, where the tightness of a mechanical fastener is critical to the overall operation of the item, torque values are experimentally determined and assigned to the individual mechanical fasteners. 
     Conventional torque limiting devices are separate from the high speed production drivers used to tighten the fastener, and must be interchanged periodically as the desired torque value is approached. This slows the assembly process as conventional torque limiting devices require time to operate. Further, many of the conventional torque limiting devices (such as a torque wrench) indicate the torque level yet do not prevent that level from being exceeded. 
     The present device is an adjustable torque limiter that can be connected between a high speed driver and the bit that couples to and rotates the mechanical fastener. When the preset torque level is reached, the torque limiter goes into a free wheel mode therein disengaging the rotational drive force from the bit. In this mode the high speed driver may continue to rotate but the bit will remain stationary. 
     The adjustability of the torque limitation is accomplished by varying the amount of spring force by which a thrust disk (coupled to the high speed driver) frictionally rotates an upper torque body (coupled to the bit) through a intervening set of steel balls that are frictionally captured in an arced (or straight) depression formed in the underside of the upper torque body. When a certain preset torque limit that is being transmitted from the driver to the bit is exceeded, the upper torque body&#39;s rotation is retarded with respect to the lower torque body&#39;s rotation and the steel balls traverse downward and outwardly along separate arced and rearward ramped radial slots formed thereon a radial torque plate extending normally from the lower torque body, gradually depressing the spring and separating the radial torque plate of the lower thrust body from the thrust disc until the balls exit the distal end of their respective radial paths and enter the outer race of the upper torque body, wherein the bit and upper torque body go into a disengaged or free wheel mode. The unit is reset by a counter rotation of lower torque body with respect to the upper torque body so that the set of balls return to the proximate end of their radial paths in the radial torque plate. 
     Simply stated, the present torque limiter overcomes all of the stated deficiencies of the traditional prior art through the use of an adjustable force coupling system between the drive and driven ends of the unit. Henceforth, the present invention would fulfill a long felt need in the fabrication industry. This new invention utilizes and combines known and new technologies in a unique and novel configuration to overcome the aforementioned problems therein reducing assembly time and preventing unnecessary damage. 
     SUMMARY OF THE INVENTION 
     The general purpose of the present invention, which will be described subsequently in greater detail, is to provide a torque limiter that is able to overcome the problems of the prior art and provide a failsafe method of quickly tightening mechanical fasteners in a production environment to a specified torque value. 
     It has many of the advantages mentioned heretofore and many novel features that result in a new and improved torque limiter which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art, either alone or in any combination thereof. 
     In accordance with the invention, an object of the present invention is to provide an improved adjustable torque limiter capable of use with a plethora of high speed drivers. 
     It is another object of this invention to provide an improved torque limiter capable of connection between a conventional mechanical driver and a conventional mechanical fastener bit. 
     It is a further object of this invention to provide an improved torque limiter capable of eliminating torque in excess of a desired preset value from being transmitted from a driver to the driven mechanical fastener. 
     It is still a further object of this invention to provide for an improved torque limiter capable of simple calibration. 
     It is yet a further object of this invention to provide an inexpensive torque limiter capable of accurate adjustment. 
     The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, both the organization and method of operation, together with further advantages and objects thereof, may best be understood by reference to the following description taken in connection with accompanying drawings wherein like reference characters refer to like elements. Other objects, features and aspects of the present invention are discussed in greater detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front side exploded view of the improved adjustable torque limiter; 
         FIG. 2  is rear side exploded view of the improved adjustable torque limiter; 
         FIG. 3  is a side perspective view of the assembled improved adjustable torque limiter; 
         FIG. 4  is a side view of the improved adjustable torque limiter; 
         FIG. 5  is a front view of the improved adjustable torque limiter; 
         FIG. 6  is cross sectional view of the improved adjustable torque limiter taken through section A-A of  FIG. 4 ; 
         FIG. 7   a  is a front view of the rear housing; 
         FIG. 7   b  is a side phantom view of the rear housing; 
         FIG. 7   c  is a rear view of the rear housing; 
         FIG. 8   a  is a front view of the rear bearing race ring; 
         FIG. 8   b  is a side cross sectional view of the rear bearing race ring; 
         FIG. 8   c  is a side phantom view of the rear bearing race ring; 
         FIG. 8   d  is a rear view of the rear bearing race ring; 
         FIG. 9   a  is a front view of the torque adjuster plate; 
         FIG. 9   b  is a side view of the torque adjuster plate; 
         FIG. 9   c  is a top view of the torque adjuster plate; 
         FIG. 9   d  is a side cross sectional view of the torque adjuster plate; 
         FIG. 9   e  is a rear view of the torque adjuster plate; 
         FIG. 10   a  is a front view of the rear spring compression disk; 
         FIG. 10   b  is a side view of the rear spring compression disk; 
         FIG. 10   c  is a rear view of the rear spring compression disk; 
         FIG. 11   a  is a front view of the compression spring; 
         FIG. 11   b  is a side view of the compression spring; 
         FIG. 11   c  is a rear view of the compression spring; 
         FIG. 12   a  is a front view of the front spring compression disk; 
         FIG. 12   b  is a side view of the front spring compression disk; 
         FIG. 12   c  is a rear view of the front spring compression disk; 
         FIG. 13   a  is a front view of the wear disk; 
         FIG. 13   b  is a side view of the wear disk; 
         FIG. 13   c  is a rear view of the wear disk; 
         FIG. 14   a  is a front view of ring bearing; 
         FIG. 14   b  is a side view of the ring bearing; 
         FIG. 14   c  is a rear view of the ring bearing; 
         FIG. 15   a  is a front view of the trust disk; 
         FIG. 15   b  is a side view of the trust disk; 
         FIG. 15   c  is a rear view of the trust disk; 
         FIG. 16   a  is a top view of the lower torque body; 
         FIG. 16   b  is a front view of the lower torque body; 
         FIG. 16   c  is a side view of the lower torque body; 
         FIG. 16   d  is a rear view of the lower torque body; 
         FIG. 17  is two series representations of torque ball positions within the lower torque body relative to the rotational slippage of the upper torque body; 
         FIG. 18   a  is a top view of the upper torque body; 
         FIG. 18   b  is a front view of the upper torque body; 
         FIG. 18   c  is a side view of the upper torque body; 
         FIG. 18   d  is a rear view of the upper torque body; 
         FIG. 19   a  is a front view of the front housing; 
         FIG. 19   b  is a side cross sectional view of the front housing; 
         FIG. 20   a  is a front view of the front bearing race ring; 
         FIG. 20   b  is a side view of the front bearing race ring; and 
         FIG. 20   c  is a rear view of the front bearing race ring. 
     
    
    
     DETAILED DESCRIPTION 
     There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated. 
     There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of descriptions and should not be regarded as limiting. 
     In the most basic description, the torque limiter  2  is an encapsulated torque decoupling mechanism that has an upper driven body and a lower drive body coupled for unitary rotation by the frictional engagement of a set of balls residing partially in radial paths formed in a concavity of the upper driven body and partially in ramped and arced radial slots formed on a radial torque plate on the lower thrust body. The amount of friction or drag exerted by the balls (and thus the coupling force between the upper driven body and a lower drive body) is altered by adjusting the compression force that a fixed spring exerts via a thrust disk onto the balls. The adjustment of the spring and the rotation of the bodies within the encapsulation requires five sets of bearings and a plethora of structural elements. This friction or drag determines the amount of torque required to break apart the unitary rotation of the two bodies. Once this torque is exceed there is slippage between the upper and lower torque bodies forcing the balls to move downward and outward along their ramped and arced radial paths and into an outer race compressing the spring and allowing the balls to rotate around a stationary upper torque body. When this occurs the drive body is free to rotate uncoupled from the driven body. To accomplish unitary rotation again, the drive body rotation must stop and the drive body rotated slightly in a reverse rotation to reset the position of the set of balls in their paths. 
     A detailed explanation of the improved torque limiter  2  as well as the functionality and structure of all its components can best be seen by looking at  FIGS. 1 and 2 . Here it is shown that the adjustable torque limiter  2  is made of a rear cylindrical housing  4  that constrains a lower outer race ring  6  affixed or formed at its proximate end. A set of lower housing balls  40  ( FIG. 6 ) affixes the lower housing  4  to an internally threaded torque adjuster plate  8 . The adjuster plate  8  contacts the rear spring location compression disk  10  which compresses spring  12  so as to exert a linear force upon front spring location compression disk  14  which is transmitted to the rear side  26  of the radial torque plate  29  of the lower torque body  22  through the wear disk  16 , bearing plate  18  and thrust disk  20 . Thrust balls  24  reside in ramped and arced radial slots  28  of the radial torque plate  29  so as lie between, yet simultaneously contact, thrust disk  20  and upper torque body  30 . Two sets of stabilizer balls  42  reside between lower torque body  22  and upper torque body  30  in two sets of conforming races so as to stabilize the upper torque body  30  when undergoing rotation movement relative to the lower torque body  22 . ( FIG. 6 ) Upper torque body  30  extends through front bearing outer race ring  34  which is affixed in the distal end of front cylindrical housing  32 . Upper housing balls  36  ( FIG. 6 ) separate yet connect upper torque body  30  to the front housing  32  by placement within groove  38  and a matingly engagable configuration in the front bearing outer race ring  34 . Front housing  32  is sized for sliding engagement over rear housing  4  so as to protect all the internal components and act as both a torque scale and a stationary surface to hold the improved torque limiter  2  as the internal components rotate. 
     Looking at  FIG. 6  the placement of the five different sets of balls can best be seen. It is these balls that both connect and allow rotation between the various components. The thrust balls  24  rotationally couple the upper torque body  30  and the lower torque body  22  as well as allow decoupled rotation between the upper torque body  30  and the lower torque body  22  when the threshold torque limit has been reached. The two rows of stabilizer balls  42  connect yet allow rotation between the upper torque body  30  and the lower torque body  22  but more importantly, act to stabilize the longitudinal axis of the torque limiter  2  to minimize wear and wobble regardless of whether the threshold torque limit has been reached. The upper housing balls  36  connect yet allow the upper torque body  30  to rotate independently of the upper housing  32  and outer race ring  34 . The lower housing balls  40  allow the lower torque body  22  and the torque adjuster plate  8  to rotated independently of the lower housing  4  and lower outer race ring  6  while connecting the lower housing  4  to the torque adjuster plate  8 . 
     Additionally, three or more adjuster balls  44  (and optionally a locking pin) are secured in the rear spring location compression disk  10 . The torque adjuster plate  8  has a ring of equidistantly spaced detents  46  that matingly conform to the adjuster balls  44 . When the torque adjuster plate  8  is rotationally engaged with the threaded end of the lower torque body  22  so as to advance, the rear spring location compression disk  10  is also forced to advance up the threaded end of the lower torque body  22 . Since the rear spring location compression disk  10  has two internal tabs  48  that engage the two longitudinal broachways  50  cut along the threaded portion of the lower torque body  22 , the rear spring location compression disk  10  does not rotate relative to the lower torque body  22 . This allows the compression of the spring  12  without any twisting that would distort the compression profile of the spring  12 , and make the precise linear torque threshold indication impossible. The adjuster balls  44  reduce the friction between the torque adjuster plate  8  and the rear spring location compression disk  10  when the torque is being adjusted, and lock into the ring of equidistantly spaced detents  46  to prevent separation between the torque adjuster plate  8  and the rear spring location compression disk  10  when the torque adjuster plate  8  has been sufficiently advanced along the threaded end of the lower torque body  22 . It is also known that in an alternate embodiment not illustrated, a more positive engagement between the torque adjuster plate  8  and the rear spring location compression disk  10  could be accomplished through the use of a set or dog screw advancing through a threaded recess in the torque adjuster plate  8  so as to partially engage a matingly sized detent in the rear spring location compression disk  10 . This would serve to lock the torque adjuster plate  8  to the rear spring location compression disk  10  therein preventing any unwanted decompression of the spring  12  once the limiting torque has been set. 
     Since the various components of the torque limiter  2  are held together by balls, there are specific ways to get the balls into their desired locations. Although the thrust balls  24  may be manually inserted during assembly, and the adjuster balls  44  are permanently affixed into the rear spring location compression disk  10 , all other balls require insertion through partially threaded externally accessible passages that then are sealed by set screws or equivalent methods. 
     The lower housing balls  40  are inserted through first passage  52  ( FIGS. 6 and 10 ) in the torque adjuster plate  8 . This first passage  52  has an “L” path that begins on the torque adjuster plate rear face  54  and exits in torque adjuster plate groove  56 . When all the lower housing balls  40  have been inserted a set screw (not illustrated) is threadingly engaged into the first passage  52  to constrain the lower housing balls  40 . 
     The two sets of stabilizer balls  42  are inserted through second passage  58  and third passage  60  ( FIGS. 6 and 18 ) in the upper torque body  30 . These passages are defined by axial paths. When all the stabilizer balls  42  have been inserted, pins are inserted into the passages and lock rings  39  are engaged around a ring groove so as to constrain the pin and stabilizer balls  42 . 
     The upper housing balls  36  are inserted through fourth passage  62  ( FIGS. 6 and 13   20 ) in the front bearing  5  race ring  34 . This fourth passage  62  has an “L” path that begins on the front bearing race ring front face  64  and exits in the groove  38 . When all the upper housing balls  36  have been inserted a set screw (not illustrated) is threadingly engaged into the fourth  10  passage  62 . 
     Looking at  FIGS. 3 and 4 , perspective views of the assembled torque limiter  2 , the decoupling torque scale  66  can be seen. This is a linear scale that coincides with the friction transmitted by the spring  12 , onto the thrust disk  20  the since the spring utilized has a linear coefficient throughout the range of spring compression utilized in the torque limiter  2 . The torque scale  66  simply reflects the relative position of the rear cylindrical housing  4  within the front cylindrical housing  32  since the rear cylindrical housing  4  is affixed to the torque adjuster plate  8  and compresses the spring  12  by threaded advancement along the threaded end of the lower torque body  22 . The scale  66  surrounds a slot  68  that allows better visual alignment of the edge of the rear cylindrical housing  4  with the scale  66 . As is well known in the art an adjustable indicator can be installed on the rear cylinder housing  4  or the torque scale  66  can be made to adjust its location on the front cylindrical housing  32 . It is also well known in the industry that the scale  66  could be placed on the lower housing  4  rather than the upper housing  32 , since it only measures the relative position of each of the housings with respect to each other (which is directly proportional to the amount of compression exerted by the spring  12 .) 
       FIG. 5  illustrates the front end of the torque limiter  2 . The proximate end of the upper torque body  30  and the socket engaging stud  98  can be seen extending through the front bearing race  34 . Although shown as a separate element, it is known that in an alternate embodiment the front bearing race  34  and upper housing  32  may be fabricated as a unitary element. 
       FIG. 7   a - c  shows the rear cylindrical housing  4  wherein it can be seen that the stepped cylindrical configuration having a smaller diameter proximate end  72  and a larger diameter distal end  74  accommodates and constrains the lower outer race ring  6 . The lower outer race ring  6  has a circumferential groove  76  formed thereon to accept the lower housing balls  40  ( FIG. 8   a - d ) and a circumferential shoulder  78  that the outer torque adjuster plate flange  80  ( FIG. 9   a - e ) rests upon. 
     The torque adjuster plate  8  is an disk that is internally threaded so as to matingly engage the threaded end of the lower torque body  22 . There are two tool recesses  82  formed therein the distal face for the insertion of a pronged tool to rotate the torque adjuster plate  8 . There is also a first passage  52  to allow the lower housing balls  40  to be installed. On the proximate face there is a circular series of equidistant detents  46  formed to jointly receive the equidistantly spaced adjuster balls  44  which are pressed into accommodating recesses (not illustrated) in the rear spring location compression disk  10  ( FIG. 10 ). 
     To ensure that the spring  12  when compressed will not twist and adjust its linear spring coefficient, the rear spring location compression disk  10  has two internal tabs  48  that lock the rear spring location compression disk  10  to the lower torque body  22 , preventing rotation relative to the lower torque body  22 . 
     The spring  12  illustrated in  FIG. 11  is a coil wound compression spring that has a linear spring coefficient across the range of compression utilized. 
     The front spring location compression disk  14  ( FIG. 12 ) is similar to the rear spring location compression disk  10  with the elimination of the adjuster balls  44  and their recesses. It is also designed to eliminate any spring twist with its own set of internal tabs  48 . 
     Looking at  FIGS. 13-15  it can be seen that the wear disk  16  is a plain flat circular washer that acts as a replaceable smooth surface for the bearing plate  18  to act against. The bearing plate  18  is a conventional needle bearing disk that allows the rotation of the thrust disk  20  from the front spring location compression disk  14 . There is raised flange  84  on the thrust disk  20  that is sized to constrain the bearing plate  18  so as to minimize any lateral movement. 
     The lower torque body  22  has a threaded distal end with two longitudinal broachways  50  cut along the threaded end. A radial torque plate  29  extends normally therefrom a forward section of the lower torque body. Into the torque plate  29  are ramped and counter clockwise arced radial slots  28  formed therethrough sized to slidingly accommodate thrust balls  24 . The torque plate distal face  86  is planar while the torque plate proximate face  88  is ramped. The ramp thickness of the torque plate  29  increases toward the center. The proximate end of the lower torque body  22  has two parallel and adjacent stabilizer grooves  90  that act as inner races for sets of stabilizer balls  42 . ( FIG. 2 ) In the distal end of the lower torque body  22  there is a square recess  92  sized to accommodate a rotating power driver such as a pneumatic ratchet, although any configured recess or boss that matingly conforms to the configuration of the driver can be utilized. 
     Referring now to  FIG. 18   a - d  the upper torque body  30  has a dished or concave distal end with grooved, clockwise arced radial paths  94  tapering deeper toward its center. The center of the distal end has a blind orifice  96  to accommodate the proximate end stub shaft  99  of the lower torque body  22 , and has two stabilizer tracks  38  ( FIG. 2 ) that act as outer races for sets of stabilizer balls  42 . Second passage  58  and third passage  60  are defined by axial paths in the upper torque body  30 . The proximate end of the upper torque body  30  has groove  38  and a socket engaging stud  98  formed thereon. 
       FIGS. 19   a  and  b  shows the front cylindrical housing  32  wherein it can be seen that the proximate end has a front bearing race recess  100  to accommodate and constrain the front bearing race  34 . The front bearing race  34  has a circumferential groove  102  formed thereon to accept the upper housing balls  36 . ( FIG. 6 ) 
     It is important to note that the upper torque body&#39;s radial paths  94  are arced in the opposite direction from the radial slots  28  formed in the radial torque plate  29  of the lower torque body  22 . It is this clockwise-counterclockwise arced relationship that forces the thrust balls  24  into their outer position when the upper torque body  30  and the lower torque body  22  are decoupled (no longer frictionally engaged). Conversely, when the innermost segments of the radial slots  28  and radial paths  94  are aligned, the thrust balls  24  are constrained in their center most location and frictional engagement is achieved. 
     The operation of the torque limiter  2  is best understood looking at looking at  FIG. 1  and the two series depicted in  FIG. 17   a - f . A two pronged fork wrench, as is well known in the mechanical arts, is inserted into the tool recesses  82  on the distal face of the torque adjuster plate  8  and is rotated to advance the torque adjuster plate  8  up (or down) the threaded end of the lower torque body  22  until the desired maximum torque is indicated on the torque scale  66 . The torque adjuster plate  8  also advances the rear housing  4  relative to the front housing  32  as they are connected by lower housing balls  40 . Adjustment will be in uniform increments set by the engagement of the adjuster balls  44  of the rear spring compression disk  10  into the detents  46  on the proximate face of the torque adjuster plate  8 . As the torque adjuster plate  8  rotationally advances up the lower torque body  22  it linearly advances the rear spring location compression disk  10  so as to compress spring  12  and increase the linear force transmitted to the thrust disk  20  through the front spring location compression disk  14 , the wear disk  16  and bearing plate  18 . The thrust disk  20  transmits an upward linear force upon the thrust balls  24  which are constrained at the alignment of the center most point of the radial torque plate&#39;s radial slots  28  and the upper torque body&#39;s radial paths  94  as illustrated in  FIG. 17   c . This alignment is achieved when the radial torque plate  29  and the upper torque body  30  are in the relative positions as shown in  FIGS. 17   a  and  b . Here approximately one half of the thrust balls  24  resides within the radial paths  94 . As the lower torque body  22  is rotated the friction or drag of the thrust balls  24  on the thrust disk  20  and the inwardly tapered center most point of the upper torque body&#39;s radial paths  94  causes a corresponding rotation of the upper torque body  30 . 
     When the limiting torque is reached, the application of more torque exceeds this frictional engagement and causes slippage between the upper torque body  30  and the lower torque body  22 . With the rotation of the upper torque body  30  retarded ( FIGS. 17   d  and  e ) the thrust balls  24  are forced along their radial paths  94  by the sides of the radial slots  28  compressing the spring  12  and increasing the distance between the thrust disk  20  and the radial torque plate  29 . As the thrust balls continue moving along the radial slots  28  and the radial paths  94 , the thrust balls  24  reach the free wheeling race  110  of the upper torque body  30  at which time the rotation of the upper torque body  30  ceases despite the rotation of the lower torque body  22 . This is illustrated in  FIG. 17   f . The rotational retardation of the upper torque body  30  relative to the torque plate  29  that is required to force the thrust balls  24  into the free wheeling race  110  is approximately 60 degrees (in a six path torque limited) as illustrated in  FIGS. 17   d  and  e . The location of the thrust balls  24  in the radial torque plate  29  when the upper torque body  30  and lower torque body are frictionally engages is shown in  FIG. 17C . The location of the thrust balls  24  in the radial torque plate  29  when the upper torque body  30  and lower torque body are decoupled is shown in  FIG. 17F . 
     To reset the torque limiter  2  requires an advancement of the upper torque body  32  by approximately 60 degrees relative to the position of the radial torque plate  30  so that thrust balls  24  can be forced back along the radial slots  28  until the thrust balls  24  are returned to the centermost position of the radial paths  94 . Since the lower torque body  22  is separated from the rear cylindrical housing  4  by lower housing balls  40 , and since the upper torque body  30  is separated from the front cylindrical housing  32  by the upper housing balls  36 , the device&#39;s outer housing is rotationally independent and may be held by the operator&#39;s hand while the torque limiter is operated. 
     The above description will enable any person skilled in the art to make and use this invention. It also sets forth the best modes for carrying out this invention. There are numerous variations and modifications thereof that will also remain readily apparent to others skilled in the art, now that the general principles of the present invention have been disclosed. For example the number and shapes of the radial slots  28  and the radial paths  94  as well as their clockwise and counterclockwise arc directions. It is also known that the arced depressions formed in the upper housing may be straight depressions as it is the arc in the torque plate that forces the thrust balls into the decoupled position. It is also known that more than one spring may be used. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.