Patent Publication Number: US-11642566-B2

Title: Adjustable four-bar linkage assembly exercise station

Description:
BACKGROUND OF THE INVENTION 
     Technical Field 
     This invention relates to the general technical field of exercise, physical fitness and physical therapy equipment and machines. This invention relates more specifically to the field of exercise stations that are operatively connected with a four-bar linkage assembly. 
     Prior Art 
     Exercise, physical fitness and physical therapy equipment and machines are available in various configurations and for various purposes, and are available for all of the major muscle groups. Some machines utilize a pivoting four-bar linkage assembly coupled with a user engagement feature such as a handle or platform to create a pushing or pulling exercise motion. Examples of these machines would include a chest press, a leg press, a shoulder press, a back-rowing machine or a back pulldown machine. The four-bar linkage assembly is generally comprised of two spaced apart stationary pivots mounted on the rigid structural frame of an exercise station or machine wherein the structural frame represents the first link. Second and third elongated links are attached to the stationary pivots at first ends and extend away from the two stationary pivots. A fourth link is pivotally coupled to the second ends of the second and third links at spaced apart locations to form a four-sided shape and a user engagement feature is operatively connected to the forth link generally at one end such that the second link, third link, fourth link and the user engagement move in a reciprocating back and forth motion during operation of the machine such that two of the pivots remain stationary on the rigid frame during operation of the machine and two of the pivots move with the reciprocating linkages during operation of the machine. 
     Generally, a four-bar linkage assembly is used to create a more elongated bio-mechanical exercise motion versus the continuous radius exercise motion of a single pivot. Based on the configuration of the four-bar linkage assembly various unique exercise motions can be created to best match the natural human bio-mechanics of a particular muscle group or sets of muscles. 
     A four-bar linkage assembly may be utilized on an exercise machine or station for various purposes. One purpose may be to create a somewhat linear motion in a space or plane where it would be difficult to place a linear motion mechanism to transport the user engagement feature. Another purpose would be to create a movement pattern wherein the user engagement feature stayed at or adjusted to a certain angle or angles through the movement pattern to better conform to human motion. The articulating motion of a leg press platform to match the user&#39;s ankle motion would be a good example of this. Another purpose would be to create a somewhat linear exercise motion that is less costly to manufacture or would be more durable and require less maintenance than a purely linear mechanism. Four-bar linkage mechanisms can be operatively connected with various types of resistance mechanism to create resistance to the exercise motion. Of the various advantages of utilizing a four-bar linkage assembly for exercise stations or machines, prior art has been limited to creating a single exercise motion per station. The present invention improves upon these features by creating a mechanism that allows the user to easily adjust the configuration of a four-bar linkage assembly such that a single exercise station can be adjusted and reconfigured to create various exercise motions. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides an adjustable configuration for a four-bar linkage assembly wherein the location of at least one of the stationary pivots can be unlatched from a first location and moved to a second location and then latched in the second location prior to operation of the exercise station. The adjustable stationary pivot is movably linked to an adjustment pivot that is stationary on the rigid frame of the station and the adjustment pivot does not move during the exercise motion of the adjustable four-bar linkage assembly. The adjustment pivot and adjustable stationary pivot are operatively connected by a linkage bar such that the adjustable stationary link can be adjusted in an orbital pattern about the adjustment pivot while the station is not being operated. The pivoting motion of the adjustment pivot can be latched to a fixed position to keep the adjustable stationary pivot in a fixed location during operation of the station and the pivoting motion of the adjustment pivot can be unlatched when the station is not being operated such that the adjustment pivot can be rotated to move the adjustable stationary pivot to a different location to create a different exercise motion. The adjustable stationary pivot can be adjusted to various locations to create various exercise motions from a single user engagement feature on an exercise station. For example, a chest press station can be reconfigured to a shoulder press station. Another example would be a back-rowing station can be reconfigured to a back pulldown station. 
     Adjusting the adjustable stationary pivot reconfigures the geometric shape of the four-bar linkage assembly and repositions the user engagement feature. Each variation of these geometric shapes of the adjustable four-bar linkage assembly creates a unique path of motion of the user engagement feature. 
     The present invention creates multiple exercises with a single exercise station thereby saving cost and reducing space requirements. 
     All embodiments of the invention can be operatively connected to various mechanisms or components to create resistance to the exercise motions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a side view of the invention in a first configuration with a user in an exercise position. 
         FIG.  2    is a side view of the invention in a first configuration with a user in an exercise position 
         FIG.  3    is a side view of the invention in a second configuration with a user in an exercise position. 
         FIG.  4    is a side view of the invention in a second configuration with a user in an exercise position. 
         FIG.  5    is a side view of the invention in a third configuration with a user in an exercise position. 
         FIG.  6    is a side view of the invention in a third configuration with a user in an exercise position. 
         FIG.  7    is a side view of the invention in a first configuration with a portion of the structural support frame removed to illustrate an unobstructed view of certain features. 
         FIG.  8    is a rear perspective view of the invention in a first configurational with a portion of the structural support frame removed to illustrate an unobstructed view of certain features. 
         FIG.  9    is an overhead closeup view of the invention to better illustrate certain features. 
         FIG.  10    is a front perspective view of the invention with a portion of the structural support frame removed to better illustrate certain features. 
         FIG.  11    is a side view of the invention wherein a first, second and third configurations of the invention are overlaid in first and second positions to better illustrate the adjustable function of the invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Exemplary preferred embodiments are disclosed below in connection with the attached drawings. Throughout this specification, various terms will be used to describe various components or features of the invention. For example, the term exercise machine will refer to any machine that can be operatively connected to the invention to create an adjustable motion exercise station. While the drawings are limited to motions that engage the torso muscles, the adjustable four-bar linkage assembly could also be configured to engage muscles in other areas of a user&#39;s body such as the arms or legs. The term exercise station refers to the components and assemblies that produce the exercise motion created by the adjustable four-bar linkage assembly and the components and assemblies that adjust the four-bar linkage assembly and the components and assemblies that lock and secure a particular configuration of the four-bar assembly prior to operation of the machine. The term pivot may refer to a bearing, rotary component, or other rotational feature of the invention. The term common axle will refer to a location where two components are coupled and rotate or pivot at the same location. The exercise motion user engagement feature, component or components can include one or more gripping handles, foot platforms, contact pads or combination thereof. The term start or starting point when referring to an exercise motion refers to the proximal location where most users would begin the range of motion of a certain exercise for a certain muscle group. The term finish or finishing point when referring to an exercise motion refers to the proximal location where most users would complete the range of motion of a certain exercise for a certain muscle group. The term resistance mechanism refers to the components of an exercise station or machine utilized to create resistance to the exercise motion of the adjustable four-bar linkage assembly and although only illustrated with a rotational resistance mechanism, the invention will work with all types resistance components and mechanisms including but not limited to weights or stacks of weight, fluid motion assemblies, rotational flywheel and fan assemblies, electrical assemblies and other mechanized resistance systems or combinations thereof including resistance mechanisms that create resistance in the push direction only or the pull direction only or in the push and pull directions of the exercise motion. 
     Other components of an exercise machine can also be a part of the exercise station including but not limited to the user support components, the resistance mechanism components and user performance information components. Other exercise stations on a single exercise machine can share the common components of the exercise machine such as the user support, resistance mechanism and user performance information components. While the drawings are limited to user support components that place the user in a seated position, the invention could also be operatively connected to an exercise station or machine that places the user in other positions such as standing, prone, supine, kneeling or other exercise positions. 
       FIGS.  1 - 11    are all views of embodiments of the invention this inventor terms “An Adjustable Four-Bar Linkage Assembly Operatively Connected To An Exercise Station”. Generally, the invention is a device that is operatively connected to an exercise machine for creating various paths of exercise motions for a single user engagement feature at a single exercise station. The invention is an improvement to a four-bar linkage assembly that creates a pushing and or pulling exercise motion such that the pushing or pulling exercise motion can be adjusted to a plurality of unique paths of motion and secured by the user prior to operating the exercise machine. In certain preferred embodiments, the four-bar linkage assembly can be adjusted by the user while the user is located in the exercise position of the exercise station. The components and supporting structure of the invention and exercise machine can be constructed of any material capable of supporting and operating the invention and exercise machine with metal components being the most common component material. 
     Referring now to  FIGS.  1 - 11   , various views and configurations of the device are shown to provide a more complete understanding of the invention. In this embodiment, the components of the adjustable four-bar linkage assembly  1  and the components of the four-bar linkage adjustment and latching assembly  20  are mounted on the structural support frame  101  of machine  100  and adjustable four-bar linkage assembly  1  is operatively connected to resistance mechanism  50  to provide resistance to the exercise motion. The seat pad  60  and back pads  61  are the supports for user U on the exercise station. 
     As disclosed in the illustrated preferred embodiments, each adjustable four-bar linkage assembly  1  is comprised of a structural support frame  101 , a first operational linkage bar  6 , a second operational linkage bar  7 , a third operational linkage bar  3 , a first movable operational pivot  2 A, a second movable operational pivot  2 B, a first movable operational pivot axle  4 A, a second movable operational pivot axle  4 B, an adjustable location operational pivot  8 , an adjustable location operational pivot axle  9 , a stationary operational pivot  12  and a user engagement feature. As previously stated herein, the exercise motion user engagement feature, component or components can be comprised of various components; however, as illustrated herein the exercise motion user engagement component or components includes a user engagement lever arm  10  and a user engagement gripping handle  11 , and will be referred to as such herein. 
     All embodiments of the invention comprise at least one adjustable four-bar linkage assembly  1  and at least one four-bar linkage adjustment and latching assembly  20  and at least one user engagement component. As illustrated herein, the invention can comprise two or more adjustable four-bar linkage assemblies  1  that are somewhat identical opposing adjustable four-bar linkage assemblies  1  that are coupled to cooperate as one and are connected to at least one user engagement feature. Also, as illustrated herein, two or more coupled adjustable four-bar linkage assemblies  1  can be adjusted by a single four-bar linkage adjustment and latching assembly  20 . Although not illustrated herein, another embodiment of the invention can comprise independent left and right side adjustable four-bar linkage assemblies  1  that are each operatively connected to a user engagement feature and are each operatively connected to a resistance mechanism. In this embodiment, the left side adjustable four-bar linkage assembly  1  would be operatively connected to a left side adjustable four-bar linkage adjustment and latching assembly  20  and the right side adjustable four-bar linkage assembly  1  would be operatively connected to a right side adjustable four-bar linkage adjustment and latching assembly  20 . 
     In the illustrated preferred embodiments, the components of the adjustable four-bar linkage assembly are assembled such that adjustable location operational pivot  8  is pivotally connected to adjustable location operational pivot axle  9  and a first end of first operational linkage bar  6  is rigidly connected to adjustable location operational pivot  8  and a second end of first operational linkage bar  6  is rigidly connected to first movable operational pivot  2 A. Stationary operational pivot  12  is rigidly mounted on structural support frame  101  and a first end of second operational linkage bar  7  is rigidly connected to stationary operational pivot  12  and a second end of second operational link bar  7  is rigidly connected second movable operational pivot  2 B. Third operational linkage bar  3  is pivotally connected to first movable operational pivot  2 A and pivotally connected to second movable pivot  2 B at spaced locations on operational linkage bar  3  with first movable operational pivot axle  4 A and second movable operational pivot axle  4 B. 
     At least one user engagement feature such as user engagement lever arm  10  is operatively connected to third operational linkage bar  3 . The user engagement feature is preferably connected to third operational linkage bar  3  at a location that is beyond the linear space between the first movable operational pivot axle  4 A and second operational pivot axle  4 B such that the adjustable path of motion of the user engagement feature can have a greater degree of variation between adjustment settings. 
     As illustrated herein, two somewhat identical opposing adjustable four-bar linkage assemblies  1  can be coupled to cooperate in one unified motion with a component such as adjustable four-bar linkages connection bar  5  wherein a first end of adjustable four-bar linkages connection bar  5  is rigidly connected to a left side third operational linkage bar  3  and a second end of adjustable four-bar linkages connection bar  5  is rigidly connected to a right side third operational linkage bar  3 . 
     As best illustrated in  FIGS.  7 ,  8 , and  9   , the four-bar linkage adjustment and latching assembly  20  is comprised of a left side stationary adjustment pivot  21  and a right side stationary adjustment pivot  21 , a left side first adjustment linkage bar  22  and a right side first adjustment linkage bar  22 , a second adjustment linkage bar  23 , a first movable adjustment pivot  24 , an adjustment connection bar  25 , a third adjustment linkage bar  26 , a second movable adjustment pivot  27 , a fourth adjustment linkage bar  28 , an adjustment assembly lever pivot  29 , an adjustment assembly lever  30 , an adjustment assembly handle  31 , an adjustment assembly handle pivot  32 , an adjustment assembly locking plate  33 , an adjustment assembly locking plate detent holes  34 , and an adjustment assembly handle detent pin  35 . The components of the four-bar linkage adjustment and latching assembly  20  are assembled such that stationary adjustment pivot  21  is rigidly mounted on structural support frame  101  and a first end of first adjustment linkage bar  22  is rigidly connected to stationary adjustment pivot  21  and a second end of first adjustment linkage bar  22  is rigidly connected to adjustable location operational pivot axle  9 . Certain embodiments such as illustrated herein comprise somewhat identical opposing left and right side adjustable four-bar linkage assemblies  1  that are coupled to move in unison. Such an embodiment comprises a right side stationary adjustment pivot  21  and a left side stationary adjustment pivot  21  and a right side first adjustment linkage bar  22  and a left side first adjustment linkage bar  22  and a right side adjustable location operational pivot axle  9  and a left side adjustable location operational pivot axle  9 . In this embodiment, a first end of an adjustment assembly connection bar  25  may be rigidly connected to a central portion of a right side first adjustment pivot linkage bar  22  and a second end of an adjustment assembly connection bar  25  may be rigidly connected to a central portion of a left side first adjustment linkage bar  22  so as to provide stability to the adjustable four-bar linkages assembly  1  while being adjusted and operated. A first end of second adjustment linkage bar  23  is rigidly connected to stationary adjustment pivot  21  and a second end of second adjustment linkage bar  23  is pivotally connected to a first end of third adjustment linkage bar  26  with first movable adjustment pivot  24 . A second end of third adjustment linkage bar  26  is pivotally connected to a first end of fourth adjustment linkage bar  28  with second movable adjustment pivot  27  and a second end of fourth adjustment linkage bar  28  is rigidly connected to adjustment assembly lever pivot  29  which is rigidly mounted on structural support frame  101 . 
     A first end of adjustment assembly lever  30  is rigidly connected to adjustment assembly lever pivot  29  and a second end of adjustment assembly lever  30  is pivotally connected to a first end of adjustment assembly handle  31  with adjustment assembly handle pivot  32 . An adjustment assembly handle detent pin  35  is rigidly connected proximal to the first end of adjustment assembly handle  31 . Adjustment assembly locking plate  33  is rigidly connected to machine structural support frame  101  proximal to adjustment assembly handle  31 . Adjustment assembly locking plate  33  is constructed with a plurality of adjustment assembly locking plate detent holes  34  for engaging adjustment assembly handle detent pin  35  with adjustment assembly locking plate  33  so as to secure four-bar linkage adjustment and latching assembly  20  and secure a unique configuration of adjustable four-bar linkage assembly  1 . 
     In all embodiments and more clearly illustrated in  FIG.  10   , adjustable four-bar linkage assembly  1  is operatively connected to a resistance mechanism  50 . As illustrated herein, resistance mechanism  50  is a rotational resistance mechanism that is centrally located between a left side adjustable four-bar linkage and a right side adjustable four-bar linkage that are coupled to create adjustable four-bar linkage assembly  1 . Said left and right side adjustable four-bar linkages are operatively connected to resistance mechanism  50  with left and right side resistance connection linkage bars  51  that are pivotally connected to left and right side first operational linkage bars  6  with left and right side resistance mechanism connection linkage bar pivots  52 . Various types of resistance mechanisms may be mounted at various locations on exercise machine  100  or operatively connected to exercise machine  100  to create resistance to the exercise motion of adjustable four-bar linkage assembly  1  and various force transfer components or combinations of components including but not limited to cables, belts, ropes, pulleys, linkage bars and clutches can be utilized to transfer the force of the exercise motion of adjustable four-bar linkage assembly  1  to a resistance mechanism. 
     The adjustable four-bar linkage assembly  1  can be adjusted to a plurality of configurations with four-bar linkage adjustment and latching assembly  20  to create a plurality of paths of exercise motions. However, the adjustable four-bar linkage assembly  1  is presented herein as being adjustable with four-bar linkage adjustment and latching assembly  20  to three primary positions of pushing and or pulling exercise motions. The invention is also presented with a rotational resistance mechanism  50  that creates resistance to both the push and pull exercise motions. Though not illustrated, the adjustable four-bar linkage assembly  1  can also be operatively connected to a resistance mechanism that creates resistance in only the push direction or only the pull direction. 
       FIGS.  1 ,  2 ,  7 ,  8 , and  11    illustrate a first exercise motion configuration of adjustable four-bar linkage assembly  1  wherein adjustment assembly handle detent pin  35  is locked into the bottom adjustment assembly locking plate detent hole  34 , which creates a more horizontal trajectory path of motion of user engagement handles  11 , which from the seated user position would be consistent with a mid-chest pressing exercise motion in the push direction and a mid-back rowing exercise in the pull direction.  FIGS.  3 ,  4 , and  11    illustrate a second exercise motion configuration of adjustable four-bar linkage assembly  1  wherein adjustment assembly handle detent pin  35  is locked into the middle adjustment assembly locking plate detent hole  34 , which adjust the adjustable four-bar linkage assembly  1  to a configuration that creates an upper angled trajectory path of motion of user engagement handles  11 , which from the seated user position would be consistent with an upper chest pressing exercise motion in the push direction and a upper back rowing exercise in the pull direction.  FIGS.  5 ,  6 , and  11    illustrate a third exercise motion configuration of adjustable four-bar linkage assembly  1  wherein adjustment assembly handle detent pin  35  is locked into the top adjustment assembly locking plate detent hole  34 , which adjust the adjustable four-bar linkage assembly  1  to a configuration that creates a more vertical trajectory path of motion of user engagement handles  11 , which from the seated user position would be consistent with a shoulder pressing exercise motion in the push direction and a back pulldown exercise in the pull direction. 
     To adjust the adjustable four-bar linkage assembly  1  from the first configuration of a mid-chest press and mid-back rowing exercise motion to the second configuration of an upper chest press and upper back rowing exercise motion, or to the third configuration of a shoulder press and back pulldown exercise motion, or to adjust the adjustable four-bar linkage assembly  1  from the second configuration of a upper chest press and upper back rowing exercise motion to the third configuration of a shoulder press and back pulldown exercise motion, user U grasps adjustment assembly handle  31  and rotates it away from adjustment assembly locking plate  33 , which removes adjustment assembly handle detent pin  35  from the bottom or middle adjustment assembly locking plate detent hole  34 . Then user U lifts adjustment assembly handle  31  upward to the position of the middle or top adjustment assembly locking plate detent hole  34 , causing adjustment assembly lever  30  to move upward and rotate about adjustment assembly lever pivot  29 , causing fourth adjustment linkage bar  28  to rotate about adjustment assembly lever pivot  29  and move downward, causing third adjustment linkage bar  26  to move downward and rotate on second movable adjustment pivot  27  and first movable adjustment pivot  24 , causing second adjustment linkage bar  23  to move downward while rotating about stationary adjustment pivot  21 , causing left and right first adjustment linkage bars  22  to move downward while rotating about stationary adjustment pivots  21 , causing adjustable location operational pivots  8  to rotate on adjustable location operational pivot axles  9  and move downward, causing first operational linkage bars  6  to move downward, causing first movable operational pivots  2 A to rotate on first movable operational pivot axles  4 A, causing third operational linkage bars  3  to rotate about second movable operational pivots  2 B, causing user engagement levers  10  to move upward and user engagement handles  11  to move upward to the upper chest press and upper back rowing exercise motion position or the shoulder press and back pulldown exercise motion position. User U then rotates adjustment assembly handle  31  towards adjustment assembly locking plate  33  to engage adjustment assembly handle detent pin  35  into the middle or top adjustment assembly locking plate detent hole to secure adjustable four-bar linkage assembly  1  prior to operating the exercise station. 
     To adjust the adjustable four-bar linkage assembly  1  from the third configuration of a shoulder press and back pulldown exercise motion to the second configuration of an upper chest press and upper back rowing exercise motion, or to the first configuration of a mid-chest press and mid-back rowing exercise motion, or to adjust the adjustable four-bar linkage assembly  1  from the second configuration of a upper chest press and upper back rowing exercise motion to the first configuration of a mid-chest press and mid-back rowing exercise motion, user U grasps adjustment assembly handle  31  and rotates it away from adjustment assembly locking plate  33 , which removes adjustment assembly handle detent pin  35  from the top or middle adjustment assembly locking plate detent hole  34 . Then user U lowers adjustment assembly handle  31  downward to the position of the middle or bottom adjustment assembly locking plate detent hole, causing adjustment assembly lever  30  to move downward and rotate about adjustment assembly lever pivot  29 , causing fourth adjustment linkage bar  28  to rotate about adjustment assembly lever pivot  29  and move upward, causing third adjustment linkage bar  26  to move upward and rotate on second movable adjustment pivot  27  and first movable adjustment pivot  24 , causing second adjustment linkage bar  23  to move upward while rotating about stationary adjustment pivot  21 , causing first adjustment linkage bars  22  to move upward while rotating about stationary adjustment pivots  21 , causing adjustable location operational pivots  8  to rotate on adjustable location operational pivot axles  9  and move upward, causing first operational linkage bars  6  to move upward, causing first movable operational pivots  2 A to rotate on first movable operational pivot axles  4 A, causing third operational linkage bars  3  to rotate about second movable operational pivots  2 B, causing user engagement levers  10  to move downward and user engagement handles  11  to move downward to the upper chest press and upper back rowing exercise motion position or the mid-chest press and mid-back rowing exercise motion position. User U then rotates adjustment assembly handle  31  towards adjustment assembly locking plate  33  to engage adjustment assembly handle detent pin  35  into the middle or bottom adjustment assembly locking plate detent hole to secure adjustable four-bar linkage assembly  1  prior to operating the exercise station. 
     To operate a pushing motion exercise with adjustable four-bar linkage assembly  1  on exercise machine  100 , user U would enter the machine in a seated position on seat pad  60  and back pads  61 . User U would then adjust the configuration of the adjustable four-bar linkage assembly  1  with four-bar linkage adjustment and latching assembly  20  to the desired exercise motion setting and latch it into position as previously described herein. To activate the exercise motion, user U would grasp user engagement handles  11  with a bent arms position while user engagement handles  11  were proximal to back pads  61  and urge user engagement handles  11  forward and or upward to an extended arms position such that user engagement handles  11  are more distal to back pads  61 . This motion would cause user engagement levers  10  to move forward and or upward, causing third operational linkage bars  3  to move forward while pivoting about second movable operational pivot  2 B on second operational pivot axle  4 B, also causing second operational linkage bars  7  to pivot forward while rotating about stationary operational pivots  12 , also causing first operational linkage bars  6  to pivot forward while rotating about adjustable location operational pivots  8 , also causing first movable operational pivots  2 A to rotate on first movable operational pivot axles  4 A, wherein the angular orientation of third operational linkage bars  3  control the motion path of user engagement levers  10  and user engagement handles  11  as third operational linkage bar  3  moves through the range of motion created by the adjustable four-bar linkage assembly  1 . 
     To operate a pulling motion exercise with adjustable four-bar linkage assembly  1  on exercise machine  100 , user U would enter the machine in a seated position on seat pad  60  and back pads  61 . User U would then adjust the configuration of the adjustable four-bar linkage assembly  1  with four-bar linkage adjustment and latching assembly  20  to the desired exercise motion setting and latch it into position as previously described herein. To activate the exercise motion, user U would grasp user engagement handles  11  with an extended arms position while the user engagement handles  11  were distal to back pads  61  and urge user engagement handles  11  rearward and or downward to a bent arms position and such that user engagement handles  11  are more proximal to back pads  61 . This motion would cause user engagement levers  10  to move rearward and or downward, causing third operational linkage bars  3  to move rearward while pivoting about second movable operational pivot  2 B on second operational pivot axle  4 B, also causing second operational linkage bars  7  to pivot rearward while rotating about stationary operational pivots  12 , also causing first operational linkage bars  6  to pivot rearward while rotating about adjustable location operational pivots  8 , also causing first movable operational pivots  2 A to rotate on first movable operational pivot axles  4 A, wherein the angular orientation of third operational linkage bars  3  control the motion path of user engagement levers  10  and user engagement handles  11  as third operational linkage bar  3  moves through the range of motion created by the adjustable four-bar linkage assembly  1 . 
       FIGS.  1 - 11    illustrate the adjustable four-bar linkage assembly  1  operatively connected to an exercise machine  100  with a single user support and multiple exercise stations. However, the adjustable four-bar linkage assembly  1  can also be operatively connected to an exercise machine that comprises one user support and no other exercise stations except for the adjustable four-bar linkage assembly  1 , or the adjustable four-bar linkage assembly  1  can also be operatively connected to an exercise machine that has multiple user supports and various exercise stations including the adjustable four-bar linkage assembly  1 . 
     Features and components of the preferred embodiment of the present invention include at least one adjustable four-bar linkage assembly, at least one user engagement feature, at least one four-bar linkage adjustment and latching assembly and at least one resistance mechanism, wherein all of the components are operatively mounted on or connected to an exercise machine to provide multiple resisted push and or pull exercise motions from a single exercise station. 
     While the invention has been described in connection with certain preferred embodiments, it is not intended to limit the spirit or scope of the invention to the particular forms set forth, but is intended to cover such alternatives, modifications, and equivalents as may be included within the true spirit and scope of the invention as defined by the appended claims. 
     REFERENCE NUMERALS 
     
         
           1  Adjustable four-bar linkage assembly 
           2 A First movable operational pivot 
           2 B Second movable operational pivot 
           3  Third operational linkage bar 
           4 A First movable operational pivot axle 
           4 B Second movable operational pivot axle 
           5  Adjustable four-bar linkages connection bar 
           6  First operational linkage bar 
           7  Second operational linkage bar 
           8  Adjustable location operational pivot 
           9  Adjustable location operational pivot axle 
           10  User engagement lever 
           11  User engagement handle 
           12  Stationary operational pivot 
           20  Four-bar linkage adjustment and latching assembly 
           21  Stationary adjustment pivot 
           22  First adjustment linkage bar 
           23  Second adjustment linkage bar 
           24  First movable adjustment pivot 
           25  Adjustment assembly connection bar 
           26  Third adjustment linkage bar 
           27  Second movable adjustment pivot 
           28  Fourth adjustment linkage bar 
           29  Adjustment assembly lever pivot 
           30  Adjustment assembly lever 
           31  Adjustment assembly handle 
           32  Adjustment assembly handle pivot 
           33  Adjustment assembly locking plate 
           34  Adjustment assembly locking plate detent hole 
           35  Adjustment assembly handle detent pin 
           50  Resistance mechanism 
           51  Resistance mechanism connection linkage 
           52  Resistance mechanism connection linkage pivot 
           60  Seat pad 
           61  Back pads 
           100  Exercise machine 
           101  Structural support frame 
         U User