Source: https://patents.justia.com/patent/4838548
Timestamp: 2019-10-18 06:35:42
Document Index: 624553185

Matched Legal Cases: ['art 1', 'art 1', 'art 1', 'art 1', 'art 1', 'art 1', 'art 1', 'art 1', 'art 1', 'art 1', 'art 1', 'art 6', 'art 1', 'art 1', 'art 6', 'art 1', 'art 1', 'arts 6', 'arts 1', 'art 1', 'arts 2', 'art 2', 'arts 2', 'arts 2', 'arts 2', 'arts 6', 'arts 2', 'art 1', 'art 1', 'arts 3', 'arts 3', 'arts 3', 'arts 3', 'arts 3', 'art 3', 'art 5', 'arts 5', 'art 5', 'arts 1', 'art 5', 'art 5', 'art 5']

US Patent for Four-bar variable resistance leg extension machine Patent (Patent # 4,838,548 issued June 13, 1989) - Justia Patents Search
Justia Patents US Patent for Four-bar variable resistance leg extension machine Patent (Patent # 4,838,548)
Four-bar variable resistance leg extension machine
Refer now to FIGS. 1 & 2 which show corresponding pictorial and side views of the preferred configuration embodiment of the disclosed invention. In general the frame of the machine is constructed primarily of round steel tubing which is welded together at the junctions where the tubes meet as shown. Welded to this tubular steel frame are steel flanges for journaling the bearings for the moving parts and steel tabs for attaching padded body-machine contact surfaces. As shown in FIGS. 1 & 2, the primary frame of the invention (assembly 1.0) consist of an irregularly shaped bent round steel tube (part 1.1) which lies directly on the machine's plane of symmetry and joins perpendicularly into the center of a second transverse straight round steel tube (part 1.2) at its forward end. Joined to the rear open end of part 1.1 is a small round steel plate (part 1.3) which lies on the ground plane and together with part 1.2 at the forward end of the machine forms a stable triangular base for the machine. Centered on the machine's plane of symmetry and joined into the top side just in front of the top of the rear bend on part 1.1 is a short straight rectangular steel tube (part 1.4) which journals a bearing at its upper end which mounts a pivotal seat back support assembly (part 1.5) whose lower end is infinitely adjustable in distance from the axis of rotation of the machine's rotating effort arm (axis A) oweing to a screw-type adjusting mechanism (part 1.6) which is mounted toward the bottom of part 1.4 as shown in FIG. 2. Centered on the machine's plane of symmetry and mounted to this pivotal seat back support assembly (part 1.5) is a back support pad (part 6.1) which engages and constrains the operator's back while performing the exercise. Centered on the machine's plane of symmetry and mounted by the seat support bracket (part 1.7) to the top side of part 1.1 just in front of the seat back support assembly is an operator seat support pad (part 6.2) which engages the operator's seat and serves the function of supporting the operator's bodyweight while performing the exercise. Mounted transversely through part 1.1 in a position at approximately the rear of the seat support pad is a handlebar bracket (part 1.8) which mounts a pair of handgrips (parts 6.4.sub.R & 6.4.sub.L) in positions where they can be gripped by the operator while performing the exercise.
Centered about the machine's plane of symmetry is a rotating effort arm assembly (assembly 2.0) which rotates about an axis (axis A) which is both parallel with the ground plane and positioned to be approximately common with the axes through the operator's knee joints while in the operating position. This rotating effort arm assembly is pivotally mounted to the machine's frame by a steel pin which is centered on axis A in frame-attached flanges (parts 1.9) which are located on the top side of the forward bend section of part 1.1 in a position between the operator's knee joints while in the operating position. It is composed primarily of two irregularly shaped bent steel plates (parts 2.1) which are both partially parallel with each other and symmetrical about the machine's plane of symmetry. These two bent steel plates are joined to each other at their upper parallel sections by a short section of angle iron (part 2.2) which lies transversely between them as shown. Journaled in a pair of short colinear bearing tubes (parts 2.4) which are mounted in the upper rearward ends of the upper parallel sections of these two bent steel plates are the bearings which engage the steel pin which mounts this assembly to the machine's frame at axis A. Mounted to the lower rearward sides of the bent out portions of the bent steel plates (parts 2.1) are a pair of shin pad mounting plates (parts 2.3.sub.R & 2.3.sub.L) which mount a pair of right and left shin-engaging pads (parts 6.3.sub.R & 6.3.sub.L) which engage the fronts of the operator's corresponding right and left shins respectively. Parallel to and offset by 4.0" from the colinear pair of bearings lying on axis A are a second colinear pair of bearings, lying on axis B, which are also journaled in the upper parallel sections of parts 2.1. This second set of bearings journals a second steel pin which is used in connecting a connecting link from the rotating effort arm assembly (assembly 2.0) to the rotating weight arm assembly (assembly 3.0). As shown in FIG. 3, the direction to axis B from axis A is along a line which forms a 102.6.degree. angle with the line connecting axis A with axis C at the beginning of the exercise movement.
As shown in FIGS. 1 & 2, this invention contains a rotating weight arm assembly (assembly 3.0) which rotates about an axis (axis C) which is both parallel with and offset by 14.0" from the axis of rotation of the rotating effort arm assembly (assembly 2.0, axis A). Like the rotating effort arm assembly, this rotating weight arm assembly is also centered about the machine's plane of symmetry and pivotally mounted to the machine's frame by a steel pin which is centered on axis C in colinear bearings which are journaled in a short transverse bearing tube (part 1.10) which is welded into part 1.1 just below the seat pad as shown in FIG. 2. It is composed primarily of two parallel triangularly shaped steel plates (parts 3.1) which are symmetrical about the machine's plane of symmetry. These two triangularly shaped parallel steel plates are joined to each other at their forward and rearward ends by two short straight rectangular steel bars (parts 3.2) which lie transversely between their respective forward and rearward ends as shown. This assembly (assembly 3.0) is pivotally mounted to the machine's frame at its rearward end by the steel pin mentioned earlier which mounts through a pair of colinear holes drilled in the rearward ends of parts 3.1 as shown. Parallel to and offset by 20.0" from the pair of colinear holes lying on axis C are a second pair of colinear holes which are drilled in the upper center sections of parts 3.1 on axis D. This second set of colinear holes journals a second steel pin which is used in connecting the connecting link mentioned earlier from the rotating effort arm assembly (assembly 2.0) at axis B to the rotating weight arm assembly (assembly 3.0) at axis D. Attached to the forward ends of these two parallel triangularly shaped steel plates (parts 3.1) and lying on an axis (axis E) which is both parallel with and separated from the assembly's axis of rotation (axis C) by a distance of 43.0" is a weight applying means which can take either the simple form of a horizontal bar (part 3.3) for loading plate weights onto or the more complex form of a selectorized weight stack assembly (assembly 5.0) which is composed of the standard rocking weight supporting rod with spaced apertures (part 5.3) which is pivotally mounted to the rotating weight arm by a steel pin at axis E and which extends down through a set of vertically stacked weights (parts 5.1) which are free to move up and down a rocking guide assembly (part 5.2) which is pivotally attached to the front of the machine's frame in frame-attached flanges (parts 1.11) at axis F and which extends up through the set of vertically stacked weights. As is conventional, a desired quantity of weights can be quickly and easily mechanically joined to part 5.3 by operator manipulation of a weight engaging key pin (part 5.4) which extends through a selected aperture in the set of weights into a mating aperture in the pivotal weight supporting rod (part 5.3). The angle formed between the line connecting axis E with axis C and the horizontal line passing through axis C is 1.3.degree. below horizontal at the beginning of the exercise movement as shown in FIG. 3.
Patent number: 4838548
Application Number: 7/239,606