Pull Down Apparatus for Exercising Regions of the Upper Body

The present invention relates to an apparati for exercising regions of the upper body, and more particularly to an improved pull down exercise machine.

A variety of exercise machines which utilize resistance or strength training have become very popular in recent years. Such strength machines are often used in place of conventional free weights to exercise a variety of muscles within the human body. Most strength machines are designed with the goal of optimizing resistance training benefits to the user by combining adjustable weight resistance with ease of use, while also attempting to maintain proper biomechanical alignment of the user's joints.

While such machines offer convenience and other benefits to the user in comparison to free weights, conventional designs typically include a frame superstructure for providing symmetrical balance and support for various levers and weight components of the machines. Such conventional frame superstructures generally result in machines that are oversized in height, width, and architecture. In addition, many of such conventional machines may be inconvenient to users performing more than one repetition of an exercise with varying weights, as the user is generally required to be physically removed from the machine in order to place weights on, or otherwise select the desired weight force before performing each set.

Another limitation found in conventional strength machines utilizing selectable weights is the inability of the user to perform high velocity exercises. In such conventonal machines the weights have inertial problems at higher speeds which can result in inconsistent resistance through a complete range of motion, therefore, users are encouraged to perform the exercises slowly. Training at lower velocities produces greater increases in muscular force at slow speeds for the user. Therefore, low velocity training only improves an individual's capabilities at slower speeds. In contrast, training at higher contractal velocities produces increases in an individual's muscular force at all speeds of contraction at and below the training velocity. Therefore, high velocity training improves an individual's functional capabilities at normal contractal velocities, i.e. velocities utilized for activities such as golfing and tennis which are more likely to be a part of every day living. Although there are many forms of strength training which allow for higher velocity training, the resistance mechanisms of such equipment generally do not include selectable weights, these devices do not utilize selectable weights as part of their resistance mechanism, and many users prefer training with selectable weights as opposed to other forms of resistance training, for example, resistance bands.

Conventional resistance equipment may also be limited by designs that prevent users from maintaining the proper biomechanical alignment of joints through a complete range of motion. A variety of machines have been proposed to improve the range of motion of the user, in order to make the exercise performed through the range more effective. Such machines are disclosed in, but not limited to, U.S. Pat. Nos. 5,437,589 and 5,273,504. However, the equipment disclosed in such references does not consistently provide proper biomechanical alignment of the user's joints through the complete range of motion.

Therefore, a need exists in the field of resistance training for selectable weight equipment that allows users to maintain the proper biomechanical alignment of joints through a complete range of motion, while performing exercises at high contractal velocities.

In accordance with the invention there is provided a pull down exercise apparatus comprising a selectable weight mechanism and a support mechanism which pivotably supports a pair of four-bar linkage mechanisms. The selectable weight mechanism is disposed in an off-center position relative to the exercise ready seating position of the user such that the user can readily access and manually adjust/select the degree of weight force from a seated, exercise ready position. The selectable weight mechanism is preferably mounted in a relatively short weight support frame, typically less than about 3.5 feet in height. The four-bar linkage mechanisms are pivotably mounted at their rearward ends about axes which are disposed at an angle relative to a horizontal plane, i.e. are tilted relative to vertical, such that a pair of elongated bars of the four-bar linkage mechanisms travel in planes which are tilted relative to vertical. A pair of handles are rigidly connected to the forward most bar component of the four-bar linkage mechanisms such that the handles follow the same pivoting movement of the forward most bar component as the four-bar linkage mechanism are pivoted around the rearward mounted, tilted axes. The tilted planes through which the four-bar linkage mechanisms travel enable the handles to travel along a slightly curvilinear downwardly diverging path which simulates as natural a human musculoskeletal downward pulling motion as possible. The four-bar linkage mechanisms are preferably mounted on an upright support. A cable and pulley are interconnected between the four linkage mechanism and the shortened selectable weight mechanism such that as the four-bar linkage mechanism is pivoted around the primary axes the selected weight is pulled through a relatively short vertical path, preferably less than about 2 feet. The distance between the point were the cables are connected to the four-bar linkage mechanisms and the forward most bar of the four-bar linkage mechanisms to which the handles are connected is such that the user has increased leverage control over the pulling of the selected weight resistance.

Accordingly, the present invention is directed to a pull down exercise apparatus that includes a base member and a support member extending from the base member. A pair of four-bar linkage mechanisms are supported by the support member. Each of the pair of four-bar linkage mechanisms includes a primary lever arm pivotable about a primary axis and a follower lever arm pivotable about a secondary axis. The primary axes are disposed at an angle with respect to each other. The primary and follower lever arms lie in a common plane tilted at an angle relative to a vertical plane, which vertical plane is perpendicular to a horizontal plane underlying the base member. The apparatus also includes a weight mechanism operatively associated with the pair of four-bar linkage mechanisms. The primary and follower lever arms travel in the common plane as the pair of four-bar linkage mechanisms are displaced between a first position and a second position while maintaining a correct biomechanical positioning of the user.

In another aspect of the invention, the pull down exercise apparatus includes a handle lever arm operatively associated with both of the primary and follower arms of each of the pair of four-bar linkage mechanisms. A handle extends from each handle lever arms, each handle extending outwardly and perpendicularly from the handle lever arm, and curving outwardly and downwardly therefrom at a 90 degree angle. The handles travel in a slightly curvilinear upwardly converging and downwardly diverging path as the four-bar linkage mechanisms are displaced between a first position and a second position, while maintaining the correct biomechanical positioning of the user.

In another aspect of the present invention, the support member includes at least one post member connected to the base member extending upwardly behind a seat. The first and second four-bar linkage mechanisms are supported on the at least one post member above and behind the seat. The primary and follower lever arms travel in the common plane as the four-bar linkage mechanisms are displaced between a first position and a second position.

In another aspect of the invention, the first and second four-bar linkage mechanisms each have a length, and are each pivotally supported at a first selected position along the length, each having a handle connected to a second selected position along the length. The apparatus includes a seat which positions a user in a disposition relative to the handles such that the handles are manually engageable by the user for pushing the handles between the first position and the second position in a pull down motion.

In another aspect of the invention, the pull down exercise apparatus includes a handle lever arm operatively associated with each of the primary and follower lever arms. The handle lever arm includes a manually engageable handle for moving the four-bar linkage mechanisms between the first and second positions. The handle is disposed in a predetermined gripping orientation in the starting position such that the operative association of the handle lever arm with the primary and follower arms maintains the handle extension in the predetermined gripping orientation during displacement of the four-bar linkage arms between the first and second positions.

In another aspect of the invention, at least one of the primary and follower lever arms of each of the four-bar linkage mechanisms is operatively associated with a cable and a selected portion of a selectable weight stack. The selected portion of the weight stack is displaced by a distance upon movement of the four-bar linkage arms from a first position to a second position.

In another aspect of the invention, the primary and follower lever arms each have a length, and a handle interconnected to a first position along the length of at least one of the four-bar linkage mechanisms. The cable is interconnected to a second position along the length of at least one of the four-bar linkage mechanisms. The first and second interconnection positions of the handle and the cable are selected such that the handle travels through a distance less than about 60% of the displacement distance of the selected portion of the weight stack upon displacement of the four-bar linkage mechanisms from a first position to a second position .

It is to be understood that the following drawings are for the purpose of illustration only and are not intended as a definition of the limits of the invention. Objects and advantages of the present invention will become apparent with reference to the following detailed description when taken in conjunction with the following drawings, which disclose an embodiment of the invention, wherein the same reference numerals identify the same feature, in which:

FIG. 1 is a perspective view of a pull down apparatus according to the present invention;

FIG. 2 is a front view of the pull down apparatus of FIG. 1;

FIG. 3 is an enlarged view of a portion of the four-bar linkage mechanisms of the pull down apparatus of FIG. 1 showing the angular disposition of the primary axes;

FIG. 4 is an enlarged view of a portion of the four-bar linkage mechanisms of the pull down apparatus of FIG. 1 showing the engagement of the stop arms;

FIG. 5 is a perspective view of a pull down apparatus of FIG. 1 in a starting or resting position;

FIG. 6 is a perspective view of the pull down apparatus of FIG. 1 in an active or extended position; and

FIG. 7 is an expanded view of the pull down apparatus of FIG. 1.

Referring initially to FIGS. 1 and 2, there is illustrated a perspective and a front view of a pull down exercise machine 10, according to one embodiment of the present invention. The pull down exercise machine 10 preferably includes a support 18 for supporting a pair of four-bar linkages 14a and 14b, as well as for supporting a seat 20, a leg stabilizer 15 adjacent the seat, a selectable weight mechanism 12 operatively connected to each of the pair of four-bar linkages 14a and 14b, and a pair of handles 16a and 16b extending from the four-bar linkages 14a and b, respectively.

In the present embodiment, the support 18 is preferably constructed of a rigid material such as steel, and includes a base member 19, a pair of post members 21a and 21b, a cross bar member 62, and an extension 23, all of which combine to form the structural elements of support 18. The base member 19 preferably includes a first support member 19a, a second support member 19b, and a mounting member 19c disposed therebetween. The first and second support members 19a and 19b are preferably disposed on a substantially horizontal, flat surface, such as a floor 17, mounting member 19c is supported at opposing ends by first and second support members 19a and 19b, and is spaced from and substantially parallel to the floor 17. Preferably a foot rest, 19d is located adjacent first support member 19a so that a user can comfortably position their feet during exercise. In the present embodiment foot rest 19d is an elongated rod preferably mounted at an angle with respect to mounting member 19c.

Referring now to FIG. 7, the post members 21a and 21b preferably extend at a slight angle from mounting member 19c, which is approximately 5 degrees from vertical axis "V" (FIG. 2) in the present embodiment, and operate to support seat 20 in a slightly reclined position. The cross bar 62 is preferably transversely mounted to the post members 21a and 21b, in the present embodiment. Extension 23 is preferably mounted between post members 21a and 21b and extends in a rearward direction therefrom. In the present embodiment, extension 23 is preferably mounted at an angle with respect to post members 21a and 21b. Support 18 may also include a pair of stop arms 35a and 35b (FIG. 3) projecting from extension 23. The stop arms 35a and 35b engage corresponding stop rods 37a and 37b which project from extensions 29a and 29b , respectively. The engagement of the stop arms 35a and 35b with the stop rods 37a and 37b limits the upward range of movement of the four-bar linkages 14a and 14b in the direction of arrow "E" especially when not in use, as shown in FIG. 2. It will be understood to one of skill in the art that any number of structural elements, having a variety of shapes, sizes and orientations, may be utilized to form the support 18, as long as the structural orientation supports the four-bar linkages as the user exercises against a selected resistance.

Referring now to FIG. 2, a seat 20 preferably includes a seat cushion 25 and a support cushion 27, which is supported in a slightly reclined position by post members 21a, and 21b is preferably adjustable between a plurality of vertical positions. The seat 20 is mounted at an angle with respect to a plane perpendicular to the floor 17 so as to properly orientate the user for performance of a pull down exercise. In the present embodiment, adjustment of the seat 20 is preferably enabled through a four-bar, gas-assist seat adjustment although other methods of adjustment, for example hydraulic, may be utilized. A pin 33 is insertable through each of a plurality of holes, in order to select the desired height of the seat. As with the support 18, the seat 20 may be designed in a variety of configurations and dimensions, and may, or may not be adjustable.

Preferably located adjacent the seat 20 and spaced therefrom is a leg stabilizer 15. The leg stabilizer 15 preferably includes a stabilizer bar 15a, leg cushions 15b and 15c and an adjustable bar 15d. The adjustable bar 15d adjusts the distance between leg stabilizer 15 and seat cushion 25. The adjustable bar 15d includes a plurality of longitudinally disposed holes (not shown) and is slidably received within sleeve 15e. The sleeve 15e includes a pin 15f disposed therethrough for selective engagement with each of the plurality of holes to selectively increase or decrease the distance the adjustable bar 15d extends from the sleeve 15e, thereby adjusting the distance between the leg stabilizer 15 and the seat cushion 25. Use of the leg stabilizer 15 with the seat 20 helps prevent a user from lifting off the seat 20 by engaging the upper thighs of the user with the cushions 15b and 15c in a comfortable manner during use of the pull down machine 10.

With reference to FIGS. 2 and 6, the selectable weight mechanism 12 is preferably a high-mass, short-travel (HMST) weight stack. An HSMT weight stack provides users with a higher mass weight stack and a shorter range of travel than conventional weight stacks. By increasing the mass and decreasing the range of travel, the speed of the selected weight decreases during use without slowing down the speed of the user, as described hereinbelow. As the speed of the weight decreases, so also does the negative inertial effect, allowing a user to train at higher contractal velocities without the associated negative inertial effect associated with conventional selectable weights. Overcoming the negative inertial effect, in turn, results in a smoother and more predictable resistance through the complete range of motion.

The selectable weight mechanism 12 is preferably disposed in an off-center position relative to the exercise ready, seating position of the user, such that the user can readily access and manually select or adjust the degree of weight force from a seated, exercise ready position. In the present embodiment, the selectable weight mechanism 12 stands approximately 35 inches in height and preferably includes a housing 22 and a plurality of selectable weight plates 24 supported therein. The housing 22 is preferably supported by a stabilizer bar 22a and a brace 22b which are both attached to the support 18. The total number of selectable weight plates 24 supported within the housing 22 are referred to collectively as a "weight stack". In the present embodiment the weight plates 24 are each approximately 0.75 inches thick, and are uniform in weight at approximately 20 lbs. each. As shown in FIG. 6, a top weight plate 28 is operatively connected to a cable 30 and a central rod 32. The central rod 32 extends in a downward direction from a top weight plate 28 through each of the consecutive weight plates 24. A pin 34 is insertable through a transverse hole in each plate, and through the central rod to select or adjust the desired amount of weight for the exercise routine to be performed, as is known in the art. The weights 24 are movable in first and second substantially vertical directions along guide rods 26a and 26b, respectively, as will be described in greater detail hereinbelow.

In the present embodiment, the selectable weight plates 24 preferably have a total mass of 400 lbs, which is twice the conventional mass (200 lbs) utilized with a pull down machine. The selected weight plates 24 travel at approximately half the speed of a selected weight plate of a conventional pull down machine. Therefore, the selected weight is also subjected to approximately half the acceleration over approximately half the distance of a conventional selected weight plate utilized with a pull down machine. The distance "W" (FIG. 6) that the selected weight plates travel is approximately 59% of the distance "DC" (FIG. 6) traveled by a user's hand, in the present embodiment, as measured by the distance between the vertical positions of handles 16a and 16b at the start and stop of the exercise. The distance "DC" is a function of the length of the user's arm. The distance a user's hand travels from the beginning to the end of one repetition of the exercise defines a complete range of motion. Although the mass is doubled, the total load the user feels during the performance of an exercise routine is the same as with a conventional pull down machine. In the present embodiment, this effect is achieved by changing the mechanical advantage to increase the leverage the user has over the selected weight plates from 0.85 (force exerted by user:weight) in a conventional system, to a 1.7 ratio. One of ordinary skill will recognize that the ratio may be changed by utilizing a system of pulleys and attaching at least one pulley to each of the four-bar linkages until the desired ratio is achieved, as determined by conventional engineering techniques.

Referring now to FIGS. 2 and 7, pulley blocks 17a and 17b preferably attach the cable 58 to one end of the extensions 29a and 29b, respectively, of primary lever arm 36a and 36b . In the present embodiment the distance "d" between the primary axle 46a and the attachment point of cable 58 to extension 29a is approximately 18 inches. It should be understood that the placement of cable 58 depends upon the desired leverage, and the desired leverage depends upon the percentage increase in the mass of the weights, as compared to conventional weights. The criteria for determining the placement of cable 58 is that while performing an exercise on the shoulder press exercise apparatus of the present invention, the user should feel a resistance comparable to that felt while performing an exercise on a conventional shoulder press exercise apparatus while being able to exercise at higher contractal velocities. The increase in mass is, in turn, determined by several considerations, such as cost, structural load placed on the apparatus by the mass, as well as the ability to readily achieve the desired leverage for a given mass.

With reference to FIGS. 1, 2, and 3, the four-bar linkage mechanisms 14a and 14b are pivotally mounted at their rearward ends to support 18, and are operatively associated with the selectable weight mechanism 12, as will be described in greater detail herein below. The four-bar linkage mechanisms 14a and 14b are symmetrical in construction, therefore, the below detailed description of linkage 14a is applicable to symmetrical linkage 14b as well. Four-bar linkage 14a preferably includes a primary lever arm 36a, a follower lever arm 38a, a handle lever arm 40a, and a support arm 42a. Preferably, the primary and follower lever arms lie and travel in a common plane which is tilted at an angle relative to a vertical plane, where the vertical plane is perpendicular to horizontal plane "A" underlying the base 19 of the apparatus. In the present embodiment, for ease of illustration, the tilted common plane is illustrated as plane "T" (FIG. 5), which is tilted with respec to vertical plane "Z" where plane "Z" is perpendicular to plane "A" and intersects the y- axis, and where the y- axis bisects the seat 27. Although the common titled plane "T" is illustrated with reference to the vertical plane "Z" any vertical may be used as a reference plane for the angular disposition of the four-bar linkages, provided such plane is perpendicular to the horizontal plane "A" underlying the apparatus, and on which it is supported, such as, for example, plane "B" in FIG. 2.

The primary lever arm 36a is preferably an elongated bar which is pivotally connected at a first, forward end to the handle lever arm 40a, by a pin 44a , at a second, rearward end, opposite the first end, to counter weight 45a, and is pivotally connected adjacent the second end by primary axle 46a , which is axially disposed about primary axis 47a. The total distance between the pivot points is approximately 30.5 inches in length in the present embodiment, however, the distance may range from approximately 25 to 35 inches. Axle 46a is mounted to support arm 42a. In the present embodiment, primary lever arm 36a preferably includes an extension 29a extending therefrom. A brace 31a (FIG. 7) may also extend between extension 29aand primary lever arm 36a to provide support for support extension 29a.

Follower lever arm 38a is likewise preferably an elongated bar which is pivotally connected at one end to handle lever arm 40a at a first pivot point 48a, by any suitable fastening device, such as a bolt, and is pivotally connected at its opposite, rearward end by secondary axle 50a, which is axially disposed about a secondary axis 51a. The distance between pivot points 48a and 50a (FIG. 3) of the follower lever arm is approximately 30.5 inches, although alternate lengths are acceptable for both the primary and follower lever arms. The distance between the pivot points of the follower lever arm 38a is preferably, but not necessarily, equal to the distance between the pivot points of primary lever arm 36a, as described above. In the present embodiment, the distance between primary axle 46a and secondary axle 50a (FIG.3) is approximately 3.75 inches. Also in the present embodiment, secondary axle 50a is mounted to support arm 42a.

With reference to FIGS. 3 and 4, in the present embodiment, the primary axes 47a and 47b are preferably disposed at an angle with respect to a horizontal plane "A" underlying the machine 10. Angle .theta. is the angle disposed between the angled axes primary 47a and 47b and is in the range of 135 to 165 degrees, and is preferably 150 degrees for a pull down machine according to the present embodiment. The primary concern with regard to the angle .theta. is that convergence take place in the direction of motion. In determining the preferred angle employed, several considerations are taken into account, including, but not limited to, the starting and ending points of a handles 16a and 16b (FIG. 1), which allows the correct biomechanical positioning of the user's wrists and forearms to be maintained. "Proper" or "correct biomechanical positioning," as used herein, means that the orientation of the user's wrist and forearm remains relatively constant from the start to finish of a shoulder press exercise motion, i.e., throughout a complete range of motion. This may also mean that it is not necessary for the user to adjust their hand position on the handles while exercising, since the handles do not twist, as in conventional exercise machines. These points help determine the maximum angle .theta., or in other terms, the maximum upward convergence of the four bar linkages 14a and 14b. In the present embodiment secondary axles 50a and 50b are preferably spaced from and parallel to primary axles 46a and 46b. Primary axles 46a, 46b are also preferably disposed parallel with respect to a plane "B" plane "B" being perpendicular to horizontal plane "A" (FIG. 2).

With continuing reference to FIG. 1, handle lever arm 40a is the forward most component of four-bar linkage 14a. Handle lever arm 40a is approximately 4.5 inches in length between pivot points 44a and 48a , although alternate lengths may be used. The handle lever arm 40a preferably includes a handle 16a extending therefrom. The handle lever arm is operatively associated with the primary and secondary lever arms such that when the primary and secondary lever arms are displaced from one position to another position, i.e. pivoted, the handle lever arm is pivoted relative to the primary and secondary lever arms around the pivot 44a and 48a but remains relatively constant in its orientation relative to the horizontal and vertical planes. In the present embodiment, follower lever arm 38a is preferably not disposed parallel with respect to primary lever arm 36a.

The handle 16a is preferably rigidly connected to the handle lever arm 40a, and preferably includes a first handle portion 16x extending in a first, perpendicular direction therefrom, and a second handle portion 16y curving outwardly from the first portion 16x, preferably at a 90.degree. angle, and preferably slightly downwardly. Such an arrangement enables a slight rotational movement of the bottom end 41a of the handle lever arm 40a in the direction of arrow "y" (FIG. 1) during operation, resulting in a slight tilt of the handle 16a through the complete range of motion. Such a slight tilt of the handle assists the user in maintaining the proper biomechanical alignment of the user's wrist and forearm during performance of the exercise, as previously described. The handle 16a is preferably rigidly connected to handle lever arm 40a, extends in a first, perpendicular direction from lever arm 40a, and curves outwardly at preferably a 900.degree. angle, and preferably slightly downwardly. With such an arrangement, a user may choose either a grip which is perpendicular or substantially parallel to the handle lever arm 40a (FIG. 1), also known as a horizontal or neutral grips, respectively. When a horizontal grip is used, i.e. when the user grasps handle portions 16x so that their hands are substantially perpendicular to the handle lever arm 40a, as shown in FIGS. 5 and 6, then the tilted axes maintain the correct biomechanical alignment of the wrists. When a neutral grip is used, i.e., when the user grasps handle portions 16y so that their hands are substantially parallel to handle lever arm 40a (not illustrated), the four-bar linkage mechanisms also enable the user to maintain the correct biomechanical alignment of the joints. In either case, the handle does not substantially twist or change orientation relative to the horizontal (A) and vertical (Z and B) planes throughout the user's complete range of motion, i.e., displacement of the four-bar linkage mechanisms. Alternatively, the handle 16a may extend at any orientation with respect to lever arm 40a, provided the orientation allows the user to comfortably grip the handle while preferably properly aligning the user's hands with respect to the user's wrists. In the present embodiment, the handle 16a is welded to handle lever arm 40a, although other attachment methods may be utilized provided that the handle 16a remains substantially stationary with respect to the handle lever arm 40a. The handle 16a is also preferably covered with foam for user comfort.

Referring now to FIG. 7, pulley system 56 preferably includes a cable 58 attached at a first end to extension 29a and is attached at a second end to extension 29b. In order to effectuate movement of the weight stack by actuation of either, or both four-bar linkages, cable 58 is routed from extension 29a, through a plurality of secondary pulleys 61a, 61b, and 61c respectively, and through floating pulley 60. From floating pulley 60, cable 58 is routed through secondary pulleys 61a, 61e and 61f for attachment to extension 29b. Secondary pulleys 61a through 61f operate to route the cable from attachment to the four linkages to the floating pulley 60 in an unobtrusive manner which is easy to access for replacement or repairs, while not interfering with the exercise motions of the user. It will be understood to those skilled in the art that because pulleys 61a through 61f are utilized to route the cable 58 to the floating pulley 60, any number of pulleys may be utilized in a variety of orientations, provided routing to the floating pulley is achieved.

Floating pulley 60 consists of a pulley 60a disposed between two side plates 60b and 60c, is connected to a pivot block 63 at one end thereof, and is movable by cable 58 in the direction indicated by arrow "C". In operation, a user will begin from a starting position, as shown in FIG. 5, and pull on handles 16a and b, either simultaneously, or one at a time, in a downward direction, indicated by arrow "X". If the handles are pulled on simultaneously, as shown in FIG. 5, both primary lever arms 36a and 36b and extensions 29a and 29b operate to put cable 58 in a state of tension, which in turn puts tension on floating pulley 60. The tension on pulley 60 is sufficient to move the pulley in the direction of arrow "C" from an initial, at rest position, to a second, active position. Alternatively, if the user chooses to pull on only one handle at a time, for example, handle 16b, then the cable is initially moved in the direction of arrow "D" (FIG. 7), as described below.

Movement of handle 16b, and hence cable 58 in the direction indicated by arrow "D" places tension on the cable, and the tension on the cable is initially transferred to primary lever arm 36a. During movement of handle 16b, handle 16a is preferably still grasped by the user. Therefore, the force initially transferred to primary lever arm 36a will not operate to move the lever arm, as the movement will be resisted by the user's grip on handle 16a. Alternatively, if the user does not resist the force from cable 58, the primary lever arm will move in the direction of arrow "F" (FIG. 7), until such time as stop arms 35a and 35b (FIG. 3) abut corresponding stop rods 37a and 37b, as previously described. In either case, the force exerted on and through cable 58 will ultimately by transferred through floating pulley 60 and will operate to move pulley 60 in the direction of arrow C, as discussed above. The above description is also applicable to movement of handle 16a, with the force being initially transferred to primary lever arm 36b. It will be understood to those skilled in the art that since the pulleys are utilized to route the cable 58 to the floating pulley 60, any number of pulleys may be utilized in a variety of orientations, as long as routing to the floating pulley is achieved.

Floating pulley 60 is attached at one end to cable 30 by pivot block 63. Thus, movement of floating pulley 60 in the direction of arrow C also operates to move cable 30 in the direction of arrow C. As shown in FIG. 1, cable 30 is routed through a pulley 68a, and then to pulley 68b attached to the exterior of weight stack 12. Cable 30 is then received within housing 22 of weight stack 12, where the cable is preferably routed through a plurality of pulleys 70a, 70b, and 70c (FIG. 7). Pulleys 70a, 70b and 70c operate to orientate the cable above the plurality of selectable weights 24, disposed within housing 22. Cable 30 exits the housing at an aperture 72 where it is operatively connected to central rod 32, as described above. Again, any number of pulleys may be utilized to route cable 30, as long as the cable is operatively connected to central rod 32.

The operation of pull down machine 10 will now be described with reference to FIGS. 1-7. Prior to performance of an exercise routine, a user will first adjust seat 20 to a desired position in which the user's feet will preferably be in contact with floor 17 or foot rest 19d. The user then selects the desired weight for performance of the exercise by inserting pin 34 into the transverse hole of the appropriate weight plate, as described above. Due to the off-center orientation of weight mechanism 12 with respect to seat 20, the user may select the weight from either a seated or a standing position. In either case, after the weight has been selected the user should be seated in seat 20 with the user's back preferably resting against support cushion 27. The direction the user is facing is considered the forward facing direction for purposes of this invention. After the user is properly seated, the user will extend his or her arms in order to grasp either one, or both, handles 16a and 16b. Once the user has grasped the handles 16a and 16b, using either the horizontal or neutral grips previously described, the user is ready to perform a pull down exercise. As stated above, when a horizontal grip is used, then the tilted axes maintain the proper alignment of the wrists, and when a neutral grip is used, the four-bar linkage mechanisms enable the user to maintain the proper biomechanical alignment of the joints.

The user performs the pull down exercise by pulling on handles 16a and 16b in a downward direction as indicated by arrow "X" (FIG. 5). As the user begins pulling in the direction as indicated by arrow "X" the bottom end 41 of handle lever arm 40a begins to rotate slightly in the direction of arrow "y" (FIG. 1), resulting in a slight tilt of handles 16a and 16b through the range of motion of the exercise, but not as much tilt as the angular deflection of primary arms 36a and 36b. This slight tilt is enabled by the four-bar linkage mechanisms 14a and 14b in order to maintain proper biomechanical alignment of the user's wrist and forearm during performance of the exercise, especially when using the horizontal grip.

As the user continues to move handles 16a and 16b in the downward direction, due to the orientation of the primary axes 47a and 47b , and secondary axes 51a and 51b, the four-bar linkage mechanisms 14a and 14b travel in planes which are tilted relative to vertical. Therefore, the four-bar linkages are non-perpendicular with respect to plane "A" underlying the machine 10, as previously described. The tilted planes through which the four-bar linkage mechanisms travel enable the handles 16a and 16b to travel in a slightly curvilinear upwardly converging and downwardly diverging path, which is illustrated as "C" in FIG. 6. Such a movement simulates as natural a human musculoskeletal downward pulling motion as possible while maintaining proper biomechanical alignment of the user's joints. As the user is pulling handles 16a and 16b in the downward direction, the cable 58 is placed in a state of tension and the floating pulley 60 is moved into the active position, as described above. Activation of the floating pulley 60 operates to move the selected weights vertically, in an upward direction within the housing 22. Once the user has fully pulled in a downward direction, as shown in FIG. 6, the user then allows handles 16a and 16b to return to the starting position for the exercise.

The handles 16a and 16b move along the same path of travel, but in the upward direction, until the handles are returned to the starting position. As the user allows the handles to move toward the starting position, the four-bar linkages once again traveling in a tilted plane, this time along a path converging in the upward direction. While the user is allowing handles 16a and 16b to return to the start position, the selected weights are moving in a vertical, downward direction, within housing 22. Once the user reaches the starting point of the exercise, one repetition has been completed through the range of motion of the user.

It will be understood that various modifications may be made to the embodiment disclosed herein. For example, all lengths and angles given are approximate and may be varied by one of skill in the art, the machine may be utilized with, or without a high-mass, short-travel weight stack, the machine may be utilized with or without a seat, the primary lever arms may be parallel without substantially effecting the biomechanical alignment of the user's joints. Therefore, the above description should not be construed as limiting, but merely as exemplifications of a preferred embodiment. Those skilled in the art will envision other modifications within the scope spirit of the invention.