Exercise treadmill

#This invention relates to electric exercise treadmills, and more particularly to electric treadmills having means for varying the inclination of the exercise surface to vary the exercise effort for a given operating speed and time, and to a safety interlock for such a variable incline treadmill.

#With the increasing use of exercise devices for therapeutic and conditioning purposes, there are a number of electric driven treadmills available, some of which have manual or power driven inclination systems taking advantage of the fact that the exercise effort, or aerobic effect, can be varied greatly with small changes in inclination. For example, a 7 percent grade doubles the aerobic or cardiovascular effect over level walking or running exercise.

#The powering of a treadmill with an electric drive has brought about the development of some power failure interlocks to protect the user, but heretofore no attention has been given to protection of third persons, particularly children, when the equipment is in use. With the elevation of the treadmill from the support floor to produce an inclination of the exercise surface, a new hazard has been introduced. It is to the protection or safety interlocking of such inclined treadmills that the present invention is directed.

#The preferred embodiments of the invention are illustrated in the drawing in which:

#FIG. 1 is a perspective view of the electric treadmill in an inclined position which has been constructed to incorporate the interlock control system of the invention;

#FIG. 2 is a perspective view of the control panel showing the speed control and switches incorporated in the invention;

#The electric treadmill embodying the invention is shown generally at 10 and includes an endless belt 12 having an exercise surface 14. The belt 12 is supported for movement within frame 16 which includes side members 18 and 20 and front member 22. Frame 16 has attached thereto side hand rails 24 and 26 and front handle 28 which is also attached to the hand rails. The rear of the frame 16 is supported on feet 30 attached to the lower rear extremities of side members 18 and 20. The forward end of frame 16 is supported by subframe 32 terminating in rollers 34. The subframe 32 is pivoted to frame 16 in a manner to provide elevation of the front end of the frame by the actuation of a screw jack tilt mechanism, all of which is not shown but is confined within the cabinet 36. Also confined within cabinet 36 is the belt drive motor and the control circuitry, more fully shown in FIG. 4. Mounted in the top of cabinet 36 for easy viewing by the user is inclinometer 38 which shows the grade or elevation of the exercise surface in 1 percent increments.

#The perimeter protection sensor or switch means of the present invention preferably takes the form of individual line or tape switches TS 1, TS 2, and TS 3 located at the bottom of side frame members 18, 20 and front frame member 22, respectively. Specifically, the switches are confined within channel members 40 attached to the lower rails 42 of frame 16 as shown in FIG. 3. Each tape switch, TS, has a bead 44 running its entire length which protrudes a short distance out of channel 44 so that any contact with the bead will close the normally open switch. A finger force of only 8 ounces exerted anywhere along the length of the switch is all that is necessary for closure. Tape switches TS 1 and TS 2 run the entire length of side members 18 and 20 from feet 30 to the front member 22 and tape switch TS 3 extends between tape switches TS 1 and TS 2 so that any object or body member passing under the frame 16 will come in contact with and close one of the switches. These tape or ribbon switches are commercialy available items. It should be understood that the perimeter switches could take other forms such as electric eye or laser beams trained along the corresponding edges to be protected. Also, microswitches can be used in conjunction with spring loaded cables mounted along the lower frame edges.

#When the user steps on the exercise surface 14 of endless belt 12, he has ready access to the control panel 46 for commencing operation of the equipment. Control panel 46 is conveniently mounted on cross bar 48 of front handle 28. Control panel 46 is connected to the motor and circuitry which i controls by cable 47 leading into cabinet 36. Referring to FIG. 2, the control panel is shown in more detail to include a main power switch in the form of key operated switch 50 and an emergency push button switch 52 to instantaneously stop operation of the equipment. The emergency switch 52 is illuminated when the key switch is turned on to indicate that power is being supplied to the unit. Speed control 54 is in the form of a potentiometer or rheostat and has a graduated scale to set the speed of the motor driving the endless belt and hence the exercise surface. The scale of the speed control is graduated from zero to nine miles per hour. In its extreme counterclockwise position, the speed control 54 passes the zero miles per hour position to an "off" position which actuates a reset speed switch not shown in FIG. 2. Tilt switch 56 is a toggle switch which is pushed in its upward position to raise the exercise surface or is pushed in its lower position to lower the exercise surface, as is clearly indicated on the panel. Finally, the control panel contains a timer module 58 which can be actuated to display the elapsed time, or a pre-set time can be set so that the timer counts down upon pushing of its start button.