System for Determining Performance on an Exercise Rowing Machine

Description

1. Technical Field

The present invention relates to exercise rowing machines in which it is desired to have readouts requiring automatic inputs of rowing arm stroke length and stroke speed to evaluate exercise performance.

2. Background Art

Exercise rowing machines commonly employ hydraulic cylinder assemblies with double-acting pistons for resisting load applied to pivoted rowing arms. The piston rods from the double-acting pistons are typically pivotally connected to the rowing arms and the cylinder components of the cylinder assemblies are typically pivotally connected to front frame members. To vary the leverage exerted by the rowing arms to change the resistance to swinging of the arms, it has been common to have the pivot for the piston adjustable along the rowing arms. In such an instance, the approach for determination of the rowing arm stroke has been to measure the maximum length of piston rod exposed during each rowing arm stroke.

An improved load-resisting hydraulic cylinder assembly has been developed in which the load resistance can be varied without changing the pivot point of the piston rods on the rowing arms. The present invention provides an improved arrangement enabling automatic monitoring of the length and speed of each rowing arm stroke and is particularly adapted for use on an exercise rowing machine equipped with such improved hydraulic cylinder assemblies. In carrying out the invention, there is provided a chopper plate at the lower end of each rowing arm which has a series of light ports arranged in an arc which passes between complementing light emitters and receivers arranged in a circuit for a microprocessor on the rowing machine programmed to calculate the stroke length and speed and maintain a stroke count responsive to the number of interruptions of light emission encountered during each swing of the chopper plates on the swing arms. The stroke reversal is determined by the use of a pair of the emitter/receiver units for each rowing arm spaced apart along the swing arc of the light ports in the chopper plate.

FIG. 1 is a perspective view of a rowing machine employing the present invention.

FIG. 2 is an exploded detail view taken at the lower end of one of the rowing arms.

FIG. 3 is a perspective view of an emitter/receiver channel unit providing two sets of light emitters and receivers separated by a gap and with the swing path of the chopper through the gap being indicated by a broken arcuate line.

Referring to FIG. 1, the invention is illustrated applied to an exercise rowing machine of the type having a longitudinal center rail 10 with side tracks 11 for sets of rollers presented by a seat carriage 12 having a seat 13 in an arrangement such as shown in U.S. Patent No. 4,541,627. The center rail 10 is secured at its forward end to a front cross-member 14 on which a pair of foot plates 15 are pivotally mounted for vertical swinging movement. At its ends, the front cross-member 14 is connected to the legs 15a of a U-shaped tubular frame member 15 which is connected at its center to the underside of the center rail 10. A rear cross-member 16 supports the rear of the center rail 10 and, together with the center rail, front cross-member 14, and U-shaped member 15, make up the frame of the machine.

Pivotally mounted by pin 17 on the U-shaped member 15 are a pair of fork units 18 which are secured to the lower ends of a pair of rowing arms 19 provided with hand grips 20. Each fork unit 18 has a pair of clevis ears 21 which are complemented by a pair of clevis ears 22 at the respective end of the front cross-member 14. Pivotally mounted by pins 23, 24 between the pairs of clevis ears 21 and 22 are a pair of adjustable hydraulic load-resisting units 26 having an adjustable resistance to flow from each side of a double-acting piston therein which is varied by turning knobs 27, 28. Such hydraulic cylinder units 26 are like those disclosed in pending application Ser. No. 917,163; filed Oct. 9, 1986.

Directing attention to FIG. 2, mounted beneath each tubular leg 15a is a foot housing 41 having inner and outer side walls 41a, 41b and front and back end walls 41c, 41d. These end walls have semicircular cutouts 41e to interfit with one of the tubular legs 15a, and the outer side wall 41b has a semicircular cutout 41f for passage of pivot pin 17. The inner side wall 41a has a relatively large curved cutout 41g to accommodate the rounded free end of the inner fork 18a of the respective rowing arm fork unit 18. This inner fork 18a has connected to the outer side thereof a semicircular chopper plate 46 having a series of light ports 46a adjacent the curved edge thereof. These light ports 146a are arranged along an arc having the pivot axis of the pivot pin 17 as a center. The curved peripheral end portion of the chopper plate 46 containing the light ports 46a is arranged to pass through a channel unit 48 having a pair of light emitters 50 on one side of the channel and a pair of opposing receivers 51 on the other side of the channel. Wires 52 to these emitters and receivers pass from the foot housings 44 into the U-frame 15 and along the U-frame to central registering openings in the U-frame and central rail 10. Then the wires extend forwardly within the center rail to an upper opening beneath a readout housing 54 mounted on the upper wall of the central rail 10 at the front thereof. This housing contains a suitable microprocessor preferably programmed to calculate (a) the speed at which the light rays from the emitters 50 are chopped by the portions of the chopper plate 46 between the light ports 46a as the chopper plate swings back and forth responsive to stroking action applied to the arms 28a by the exercising person; (b) the number of light ports 46a passing the emitters during each stroke to determine the length of each stroke; (c) the direction of the stroke (forward and rearward); and (d) the total number of strokes during the exercise period. The microprocessor is also preferably programmed to receive inputs of the pressure settings on the ends of the hydraulic cylinder assemblies 26 and calculate the total calories expended from the start of the exercise period, and to calculate the force exerted by the exerciser during each stroke. The results of the calculations are preferably displayed at the face of the readout housing 54.