Numerous beneficial effects upon the human body of various physical forces and motions such as vibration and massage have long been recognized. Accordingly, there have been a variety of devices and machines, both manual and automatic, i.e., electrical or motor driven, for applying physical forces to the body. Some of the most known automatic massaging devices take the form of a table or chair. The user rests comfortably on the table or chair while receiving the beneficial massaging treatment, often to the back or the legs. The massaging chairs are particularly appealing to users desiring the massage because one can either use the chair as an ordinary piece of furniture or else passively sit in it and utilize its massaging actions.
These massaging chairs conventionally have used a vibration mechanism such as rollers positioned within the back of the chair to provide a vibratory massaging action to the user. The vibration mechanism may be stationary or may vertically travel up and down the back of the chair. Examples of such chairs may be seen in U.S. Pat. No. 3,322,116 by Murphy et al. entitled "Vibratory Massage Apparatus" and U.S. Pat. No. 2,827,044 by Orthwine entitled "Portable Massaging Apparatus." These vibration mechanisms by themselves, however, usually provide little physical force against the back of the user and, therefore, provide little muscular massage.
Other massaging chairs have recently used back-pressure type rollers which vertically travel up and down the back of the chair and contact a flexible front surface of the back which, in turn, contacts the back of the user. These back-pressure type rollers have attempted to provide a stronger muscular massage to the back of the user. Examples of such chairs may be seen in U.S. Pat. No. 5,137,016 by Yamasaki et al. entitled "Automatic Multifunction Massager For Chair", U.S. Pat. No. 4,615,336 by Fijimoto entitled "Automatic Massaging Machine", U.S. Pat. No. 4,574,786 by Hashimoto et al. entitled "Massage Apparatus", and U.S. Pat. No. 4,718,408 by Barreiro entitled "Variable Massage Apparatus Having A Clutch Selectively Engaging Alternate Gears." Although these back-pressure type roller mechanisms have experienced some success in the industry, these mechanisms have provided little or no kneading of the back muscles which has many beneficial effects to the user.
Massaging chairs having a kneading-type mechanism therein have recently been developed for providing the beneficial effects of kneading the back muscles of the user. Examples of these kneading-type mechanisms may be seen in U.S. Pat. No. 5,020,518 by Spears et al. entitled "Travelling Roller Massage Apparatus" and U.S. Pat. No. 4,454,867 by Swanson entitled "Therapeutic Chair Assembly." These kneading-type mechanisms often provide a kneading roller which reciprocates up and down the back of the chair, but often in a non-uniform pattern. Other kneading-type mechanisms provide a kneading-type pressure on the user's back, but little or no concentrated and strong kneading-type pressure.