More and more people, especially the elderly, suffer from various musculoskeletal indications such as osteoporosis, fracture, bone loss, osteoarthritis, low back pain, neuromuscular ailment, circulation problem in lower limb and the like. The prevention and treatment for musculoskeletal indications is required.
Low magnitude and high frequency vibration has been proven to be beneficial to several musculoskeletal indications, which provides non-pharmacological treatment and prevention of osteoporosis and associated problems. Conventional low magnitude and high frequency vibration devices generally use mechanical parts (such as springs and levers) in contact with each other as a driving unit. The mechanical wear-out and metal fatigue may reduce the serviceable life and increase power consumption and the maintenance cost.
U.S. Patent Publication No. US 2006/0241528A1 discloses a system for a low profile vibrating plate, which uses magnetic fields to provide vertical vibration motion to a platform so as to allow the system to have a lower profile. This published system allows for a more compact form-factor for the vibrating plate, which allows for increased portability. Additionally, since mechanical parts are eliminated, the vibrating plate of the published system has increased reliability.
However, neither those conventional devices employing mechanic parts nor the published system of U.S. Patent Publication No. US 2006/0241528A1 addresses the issue of non-stable frequency and magnitude of vibration in view of the change of weights of users. In order to ensure the effectiveness of therapy for users having different weights, the body weight has to be measured and this parameter has to be manually input. This may introduce erratic response if there is any error in this parameter from the measurement (if not done correctly) or human input. Moreover, none of known devices provides a feasible solution to regulate the frequency and magnitude of vibration when the device is in use. Furthermore, the published system of US Patent Publication No. US 2006/0241528A1 has one set of magnets consisting of static magnets and dynamic magnets to handle the weight of the load and generation of vibration. To support user's weight (˜100 kg) using ordinary electromagnet (the most popular dynamic magnet), high electricity consumption is necessary to generate the force. Besides, since no magnetic shielding facility is used in the US Patent Publication No. US 2006/0241528A1, users may be surrounded by magnetic field due to possible leakage of magnetic field, which will produce undesirable influences to the human body, as specified by WHO (Environmental Health Criteria (2007), Extremely low frequency fields, Geneva: World Health Organization, Monograph, No.238) and ICNIRP (Guidelines on limits of exposure to static magnetic fields. Health Phys. 66(1), 100-106).