Shoulder press apparatus for exercising regions of the upper body

[0002] This application is a continuation of U.S. patent application Ser. No. 08/941,595 now U.S. Pat. No. 5,971,896 titled “Shoulder Press Apparatus for Exercising Regions of the Upper Body,” filed Sep. 30, 1997 by Giannelli et al., and which is incorporated herein by reference in its entirety.

[0003] 1. Field of the Invention

[0004] The present invention relates to an apparati for exercising regions of the upper body, and more particularly to an improved shoulder press exercise machine.

[0005] 2. Related Art

[0006] 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.

[0007] 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 conventional 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.

[0008] 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.

[0009] 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.

[0010] In accordance with the invention there is provided a shoulder press exercise apparatus comprising a selectable weight mechanism and a support member pivotally supporting 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 pivotally 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 mechanisms are pivoted around the rearward mounted, tilted axes. When utilizing a neutral grip the four-bar linkage mechanisms enable the user to maintain the proper biomechanical alignment of the joints. If a horizontal grip is utilized then the tilted axes maintain the proper alignment of the wrists. The tilted planes through which the four-bar linkage mechanisms travel enable the handles to travel along a slightly curvilinear upward converging path which simulates as natural a human musculoskeletal upward pushing motion as possible. The four-bar linkage mechanisms are preferably mounted to an upright support. A cable and pulley are interconnected between the four-bar linkage mechanisms and the shortened selectable weight mechanism such that as the four-bar linkage mechanisms are pivoted around their corresponding primary axis the selected weight is pulled through a relatively short vertical path, preferably about 1 foot. The distance between the point where 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.

[0011] Accordingly, the present invention is directed to a shoulder press 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.

[0012] In another aspect of the invention, the shoulder press 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.

[0013] 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.

[0014] 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 shoulder press motion.

[0015] In another aspect of the invention, the shoulder press 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.

[0016] 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.

[0017] 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.

[0018] 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, in which:

[0019] FIG. 1 is a perspective view of a shoulder press apparatus according to the present invention;

[0020] FIG. 2 is an enlarged view of the shoulder press apparatus of FIG. 1 showing rear-ward pivot points of the four-bar linkage mechanisms;

[0021] FIG. 3 is a front view of the shoulder press apparatus of FIG. 1 illustrating various planes of reference;

[0022] FIG. 4 is a side view of the shoulder press apparatus of FIG. 1 showing a portion of a four-bar linkage mechanism;

[0023] FIG. 5 is an enlarged view of the shoulder press apparatus of FIG. 1 showing the angular disposition of the primary axes;

[0024] FIG. 6 is an exploded view of the shoulder press apparatus of FIG. 1;

[0025] FIG. 7 is a front view of the shoulder press apparatus of FIG. 1 showing a user in a starting position grasping the handles with a horizontal grip;

[0026] FIG. 8 is a front view of the shoulder press apparatus of FIG. 1 showing a user in an active position grasping the handles with a horizontal grip;

[0027] FIG. 9 is a front view of the shoulder press apparatus of FIG. 1 showing a user in a starting position grasping the handles with a neutral grip; and

[0028] FIG. 10 is a front view of the shoulder press apparatus of FIG. 1 showing a user in an active position grasping the handles with a neutral grip.

[0029] Referring initially to FIG. 1, a perspective view of a shoulder press machine 10 according to one embodiment of the present invention is illustrated. The shoulder press machine 10 preferably includes a support 18 for supporting a seat 20 and a pair of four-bar linkage mechanisms 14aand 14b. Machine 10 also preferably includes a selectable weight mechanism 12 operatively connected to each of the four-bar linkage mechanisms 14aand 14b, and a pair of handles 16aand 16bextending from the four-bar linkages 14aand 14b, respectively.

[0030] 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 21aand 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 19cdisposed therebetween. The first and second support members 19aand 19bare preferably disposed on a substantially horizontal, flat surface, such as a floor 17. Mounting member 19cmay preferably be supported at opposing ends by first and second support members 19aand 19b, and may preferably be spaced from and substantially parallel to the floor 17.

[0031] Referring now to FIGS. 1 and 6, post members 21aand 21bpreferably extend at a slight angle, which is approximately 5° from a vertical axis (illustrated as “v” in FIGS. 1 and 3), and operate to support the seat 20 in a slightly reclined position. The cross bar 62 is preferably transversely mounted to the post members 21aand 21b, while extension 23 is preferably mounted between the post members 21aand 21b, and extends in a rearward direction therefrom. The support 18 may also include a pair of stop arms 35aand 35bprojecting from primary lever arms 36aand 36b, respectively. Each of the stop arms 35aand 35bpreferably include rollers 37aand 37b, respectively, which engage the support member 18 when the machine 10 is not in use, while also operating to limit the downward movement of the four-bar linkages 14aand 14bin the direction of arrow “E”. 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, provided the structural orientation supports the four-bar linkages as the user exercises against a selected resistance.

[0032] With reference again to FIG. 1, the seat 20 preferably includes a seat cushion 25 and a support cushion 27. The seat 20 is preferably supported in a slightly reclined position by the post members 21aand 21b, and is 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 to provide the proper orientation of the user for performance of a shoulder press exercise. 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 is known in the art. 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.

[0033] With continued reference to FIG. 1, the selectable weight mechanism 12 is preferably a high-mass, short-travel (HMST) weight stack. A HMST weight stack provides the user 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 he or she exercises, 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, as described above. Overcoming the negative inertial effect, in turn, results in a smoother and more predictable resistance through the complete range of motion.

[0034] 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 22aand a brace 22b(FIG. 6) which are both attached to the support member 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. 8, 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 the 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 26aand 26b, respectively, as will be described in greater detail hereinbelow.

[0035] 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 shoulder press machine. The selected weight plates 24 travel at approximately half the speed of a selected weight plate of a conventional shoulder press 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 conventional shoulder press machine. The distance “W” (FIG. 10) that the selected weight plates travel is approximately 41% of the distance “DC” (FIG. 7) traveled by a user's hand, in the present embodiment, as measured by the distance between the vertical positions of handles 16aand 16bat 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 shoulder press 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 1.2:1 (force exerted by user:weight) in a conventional system, to a 2.4:1 ratio for the present system. One of ordinary skill will recognize that the ratio may be changed by attaching the cable 58 (FIG. 6) at an appropriate attachment point along the primary lever arms 36aand b, as determined by conventional engineering techniques.

[0036] Referring now to FIG. 5, pulley blocks 17aand 17bpreferably attach the cable 58 at a point approximately mid-way between first pivot points 44aand 44b(FIG. 1), and second pivot points 46aand 46b, of the primary lever arms 36aand 36b, respectively. In the present embodiment, the pulley blocks 17aand 17bare attached at approximately 41% of the distance between second pivot points 46aand 46band first pivot points 44aand 44b(FIG. 1), where the distance is measured starting from the second pivot points 46aand 46b. Also in the present embodiment, the total distance between the first and second pivot points is approximately 30.5 inches, although distances in the range of approximately about 25 inches to about 35 inches may be used. 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 or a given mass.

[0037] With continued reference to FIGS. 1 and 4, four-bar linkage mechanisms 14aand 14bhaving a length “L”, 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 hereinbelow. The four-bar linkages 14aand 14bare symmetrical in construction, therefore, the below detailed description of linkage 14ais applicable to symmetrical linkage 14bas well. The four-bar linkage 14apreferably includes 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. 1), which is tilted with respect to the vertical plane “Z”, where the plane “Z” intersects and is perpendicular to plane “A”, 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 horizontal plane “A” underlying the apparatus, such as, for example, plane “B”.

[0038] The primary lever arm 36ais preferably an elongated bar which is pivotally connected at a first, forward end to the handle lever arms 40a, by a pin 44a, at second, rearward end, opposite the first end, to a counter weight 45a, and is pivotally connected adjacent the second end about primary axle 46a, which is, in turn, axially disposed about primary axis 47a(FIG. 5).

[0039] Follower lever arm 38ais likewise preferably an elongated bar which is pivotally connected to at one end to handle lever arm 40aat a first pivot point 48a, by any suitably fastening device, such as a bolt, and is pivotally connected at its opposite, rearward end by secondary axle 50a(FIG. 5), which is, in turn axially disposed about secondary axis 51a(FIG. 4). The distance between the pivot points 48aand 50aof the follower lever arm is approximately 30.5 inches, although distances in the range of approximately about 25 inches to about 35 inches may be used. Additionally, alternate lengths are acceptable for both the primary and follower lever arms. The distance between the pivot points of the follower lever arm 38ais preferably, but not necessarily, equal to the distance between the pivot points of primary lever arm 36a, as described above.

[0040] In the present embodiment, the distance between primary axis 46aand secondary axle 50a(FIG. 2) is preferably approximately 3.75 inches. Also in the present embodiment, the secondary axle 50ais mounted to a block 52awhich is part of the support arm 42a. The block 52ais preferably welded to the support arm 42a, but may be attached in any suitable manner as long as the block 52aremains stationary while supporting the follower lever arm 38a. Alternatively, the secondary axle 50amay be directly mounted to the support arm 42a.

[0041] With reference now to FIG. 5, in the present embodiment, the primary axes 47aand 47bare preferably disposed at an angle with respect to a horizontal plane “A” (FIG. 3) underlying the machine 10. Angle θ is the angle disposed between the angled axes 47aand 47b, which is preferably 150 degrees in the present embodiment, although an angle in the range of 135 to 165 degrees may be used. The primary concern with regard to the angle θ is that convergence take place in the upward, or pushing direction. 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 16aand 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 θ, or in other terms, the maximum upward convergence of the four-bar linkages 14aand 14b. In the present embodiment, the secondary axles 50aand 50bare preferably spaced from and are parallel to the primary axles 46aand 46b. The primary axes 47aand 47bare also preferably disposed parallel with respect to a plane “B,” plane “B” being perpendicular to horizontal plane “A” (FIG. 3).

[0042] With continued reference to FIG. 1, the handle lever arm 40ais the forward most component of four-bar linkage 14a. The handle lever arm 40ais approximately 4.5 inches in length as measured between pivot points 44aand 48a, although alternate lengths may be used. The handle lever arm 40apreferably includes a handle 16aextending 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 points 44aand 48a, but remains relatively constant in its orientation relative to the horizontal and vertical planes. In the present embodiment, follower lever arm 38ais preferably not disposed parallel with respect to primary lever arm 36a. Such an arrangement enables a slight rotational movement of the bottom end 41aof the handle lever arm 40ain the direction of arrow “Y” during operation, resulting in a slight tilt of the handle 16athrough 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.

[0043] The handle 16ais preferably rigidly connected to the handle lever arm 40a, and preferably includes a first handle portion 16xextending in a first, perpendicular direction therefrom, and a second handle portion 16ycurving outwardly from the first portion 16x, preferably at a 90° 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, also known as horizontal or neutral grips, respectively. When a horizontal grip is used, i.e. when the user grasps handle portions 16xso that their hands are substantially perpendicular to the handle lever arm 40a, as shown in FIGS. 7 and 8, 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 portion 16yso that their hands are substantially parallel to handle lever arm 40a, as shown in FIGS. 9 and 10, 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 16amay extend at any orientation with respect to the handle lever arm 40a, provided the orientation allows the user to comfortably grip the handle while preferably maintaining proper biomechanical alignment of the user's hands with respect to the user's wrists throughout the user's complete range of motion. In the present embodiment the handle 16ais welded to the handle lever arm 40a, although other attachment methods may be utilized provided that the handle 16aremains substantially stationary with respect to the handle lever arm 40a. The handle 16ais also preferably covered with foam for user comfort.

[0044] Referring now to FIG. 6, a pulley system 56 preferably includes a cable 58 attached at a first end to the primary lever arm 36aand at a second end to the primary lever arm 36b. In the present embodiment, as shown in FIG. 5, the cable 58 is preferably attached by pivot blocks 17aand 17bto both primary lever arms 36aand 36b, respectively. As previously discussed, the cable 58 is attached by the pulley blocks 17aand 17bat approximately 41% of the distance between the second pivot points 46aand 46b, and the first pivot points 44aand 44b, where the distance is measured starting from the second pivot points 46aand 46b, in order to increase the mechanical advantage the user has over the weight to be lifted.

[0045] In order to effectuate movement of the selected weight by actuation of either, or both four-bar linkages, the cable 58 is routed from the primary lever arm 36b, through a plurality of secondary pulleys 61a, b,and c, respectively, and through a floating pulley 60. From the floating pulley 60, the cable 58 is routed through a plurality of secondary pulleys 61d, e,and ffor attachment to the primary lever arm 36a. The secondary pulleys 61a-foperate to route the cable from attachment to the four-bar linkages to the floating pulley 60 in an unobtrusive manner, providing easy access for replacement or repairs, while not interfering with the exercise motions of the user. It will be understood by those skilled in the art that because the secondary pulleys 61athrough fare 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.

[0046] With reference to FIGS. 4-6, the floating pulley 60 preferably consists of a pulley 60adisposed between two side plates 60band 60c, which is connected to a pivot block 63 at one end thereof, and is movable by cable 58 in the direction indicated by arrow “C” (FIG. 6). In operation, a user will begin at an initial or starting position, as shown in FIG. 4, and push on handles 16aand 16bin an upward direction indicated by arrow “E” (FIG. 6) either simultaneously, or one at a time. If the handles are pushed upward simultaneously, as shown in FIG. 5, both primary lever arms 36aand 36boperate to put the cable 58 in a state of tension, thereby placing tension on the floating pulley 60. The tension on the floating pulley 60 is sufficient to move the pulley in the direction of arrow “C” (FIG. 6) from an initial, at rest position, to a second, active position. Alternatively, if the user chooses to push on only one handle at a time, for example, handle 16b, then the cable is initially moved in the direction of arrow “D” (FIG. 6), as described below.

[0047] Movement of the handle 16b, and hence the cable 58 in the direction indicated by arrow D, places tension on the cable, which is initially transferred to the primary lever arm 36a. During movement of the handle 16b, handle 16ais preferably still grasped by the user. Therefore, the force initially transferred to the primary lever arm 36awill 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. 6), until such time as the primary lever arm 36aabuts roller 37aof the stop arm 35a, which operates to stop the downward movement of the four-bar linkages 14aand 14bin the direction of arrow “E”, as previously described. In either case, the force exerted on and through cable 58 will ultimately be transferred through the floating pulley 60 and will operate to move the pulley 60 in the direction of arrow C, as discussed above. The above description is also applicable to the movement of handle 16a, with the force being initially transferred to the primary lever arm 36b. It will be understood by 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.

[0048] With continued reference to FIG. 6, the floating pulley 60 is attached at one end to the cable 30 by a pivot block 63. Thus, movement of the floating pulley 60 in the direction of arrow “C” also operates to move the cable 30 in the direction of arrow C. The cable 30 is routed through a pulley 68 attached to the exterior of the selectable weight mechanism 12. As shown in FIG. 6, the cable 30 is then received within the housing 22 of the selectable weight mechanism 12, where the cable is preferably routed through a plurality of pulleys 70a, 70band 70c. Pulleys 70a, 70band 70coperate to orientate the cable above the plurality of selectable weights 24 disposed within the housing 22. The cable 30 exits the housing at an aperture 72 where it is operatively connected to the central rod 32, as described above. Again, any number of pulleys may be utilized to route the cable 30, as long as the cable is operatively connected to the central rod 32.

[0049] The operation of the shoulder press machine 10 will now be described with reference to FIGS. 1 through 10. Prior to performance of an exercise routine, a user will first adjust the seat 20 to a desired position in which the user's feet will preferably be in contact with the floor 17. The user then selects the desired weight for performance of the exercise by inserting the pin 34 into the transverse hole of the appropriate weight plate, as described above. Due to the off-center orientation of the selectable weight mechanism 12 with respect to the 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 the seat 20 with the user's back preferably resting against the 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 16aand 16b. Once the user has grasped the handles 16aand 16bin either a horizontal or neutral grip as previously described, the user is ready to perform a shoulder press exercise. As stated above, when a horizontal grip is used (FIGS. 7 and 8), then the tilted axes maintain the proper alignment of the wrists, and when a neutral grip is used (FIGS. 9 and 10), the four-bar linkage mechanisms enable the user to maintain the proper biomechanical alignment of the joints.

[0050] The user performs the shoulder press exercise by first pushing on the handles 16aand 16bin an upward direction (indicated by arrow “X” FIGS. 7 and 9). As the user begins pushing in the direction indicated by arrow “X”, the bottom end 41aof the handle lever arm 40abegins to rotate slightly in the direction of arrow “Y” (as shown in FIG. 1), resulting in a slight tilt of the handles 16aand bthrough the range of motion of the exercise, but not as much tilt as the angular deflection of the primary arms 36aand 36b. This slight tilt is enabled by the four-bar linkage mechanisms 14aand 14bin order to maintain the proper biomechanical alignment of the user's wrist and forearm during the performance of the exercise, especially when utilizing the horizontal grip.

[0051] As the user continues to move handles 16aand bin the upward direction, due to the orientation of primary axes 46aand 46b, and secondary axes 50aand 50b, the four-bar linkage mechanisms 14aand 14btravel in planes which are tilted relative to vertical. Therefore, the four-bar linkage mechanisms 14aand 14bare non-perpendicular with respect to the plane “A” underlying the machine 10, as previously described. The tilted planes through which the four-bar linkage mechanisms travel enable the handles 16aand 16bto travel in a slightly curvilinear upwardly converging and downwardly diverging path, which is illustrated as “C” in FIGS. 7 and 8. Such a movement simulates as natural a human musculoskeletal upward pushing motion as possible while maintaining proper biomechanical alignment of the user's joints. As the user is pushing the handles 16aand 16bin the upward direction, the cable 58 is placed in a state of tension and the floating pulley 60 is moved into the active position, as previously described. 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 extended his or her arms in an upward direction (as shown in FIGS. 8 and 10), the user then allows handles 16aand 16bto return to the starting position for the exercise.

[0052] The handles 16aand 16bmove along the same path of travel, but in the downward 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 travel in a tilted plane, this time along a path diverging in the downward direction. While the user is allowing handles 16aand 16bto return to the start position, the selected weights are moving in a vertical, downward direction, within the 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.

[0053] 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 and spirit of the invention.