The present invention relates to a system for using and powering electrical power tools. More particularly, it relates to a system which provides a hand-held power tool having reduced weight over the same tools of prior art, to alleviate the symptoms of Carpal Tunnel Syndrome in persons using such power tools for extended time periods on a daily basis.
Carpal tunnel syndrome is a disorder characterized by a specific pattern of numbness, tingling, pain or weakness caused by nerve compression in the wrist. It occurs because the carpal tunnel (the rather narrow passageway for the median nerve, a major nerve that provides sensation to the thumb, index finger, middle finger and half of the ring finger) is normally quite narrow, and even a small additional narrowing or other injury leads to nerve irritation. There are several common causes of carpal tunnel, including: arthritis or fracture near the wrist; pregnancy; diabetes; overuse (as in typists, cashiers or certain athletes); and thyroid disease, particularly an underactive thyroid. In each of these conditions, there is either nerve injury or added pressure in the carpal tunnel. Often the condition occurs without a clear reason. Carpal tunnel syndrome can occur in one or both hands.
Symptoms of carpal tunnel syndrome may include burning, tingling or numbness of the fingers, difficulty gripping tools or other implements, and problems making a fist. Symptoms may appear first at night and are most noticeable in the thumb and the index and middle fingers. People with carpal tunnel syndrome often describe awakening with a tingling sensation and the need to “shake out” the hands to recover normal sensation. There may be pain in the wrist that radiates into the hand or into the forearm. If the condition is not treated, the muscles of the thumb may eventually waste away so that the normal “hill” of muscles at the base of the thumb eventually flattens.
Carpal tunnel syndrome presents a major problem for persons engaged in various occupations for which the nature of daily routine tasks requires the hands to be subjected to continued and repeated stressful movements or positions conducive to carpal tunnel. In such cases, carpal tunnel syndrome can render the person useless in their job function. One particular job function which is susceptible to the effects of carpal tunnel is those involving the use of hand-held power tools, including power drills and the like.
Typically, hand-held power tools comprise an outer casing, a motor, and other physical mechanisms such as reduction gears, chucks, clutches, and the like which contribute to the overall weight of the power tool. Power tools also include a portion that is intended to be grasped or gripped by the user of the tool. The nature of the job for which a given power tool is designed typically dictates the weight distribution of the various elements from which the power tool is constructed within the power tool itself When the human hand grasps an article, such as a power tool, gravitational forces acting upon the tool tend to apply a stress to the muscles of the hand and wrist of the person grasping the tool, with such forces depending upon the design configuration requirements of the power tool. That is to say, different muscles of the hand and wrist will be stressed differently by virtue of the design configuration weight distribution of a power tool.
The typical hand-held power drill comprises a handle portion which is to be grasped by the user and an upper portion in which is contained the motor, reduction gears, chuck, and other elements known in the art. In the case of power drills which are battery-powered, it is common for the batter to be housed within the handle portion itself, or to be disposed at the lower end portion of the handle portion. However, the held power drills of the prior art which contain a battery in the handle portion or disposed near its end are relatively heavy, especially since the battery adds a great amount of relative weight. This presents a problem in which carpal tunnel syndrome may become manifest for workers who use such hand-held drills in compact areas on a routine basis, such as drilling which is required on the inside of cabinets or other non-readily accessible locations. The prior art contains disclosures which relate to powering means for hand-held tools such as cordless drills and the like. For example, U.S. Pat. No. 1,530,342 discloses a belt containing a battery pack, which is used to power a head-mounted or hat-mounted lamp for use by miners. U.S. Pat. No. 3,274,476 teaches an improved belt construction which is to be worn about the waist of an operator of a given electrically actuated device, wherein the belt construction is adapted to carry a plurality of electric cells which may be of the rechargeable type for powering the electrically actuated device. U.S. Pat. No. 3,828,201 sets forth a portable power package so constructed and designed as to be capable of providing a 12 volt or a 6 volt output by manipulation of at least one of 20 the batteries in the case. The power package can be strapped to the body or carried by hand. Another aspect of the invention is to provide a portable head lamp with accompanying carrying case which is simple and easy to use, and which is operated from the portable power package. U.S. Pat. No. 3,919,615 provides a power belt which contains an inverter, and is thus capable of supplying AC or DC voltages to various devices. U.S. Pat. No. 4,748,344 discloses a portable power supply carrier that comprises an internally wired belt to be worn around a user's waist. The belt has pairs of electrical connectors spaced along its length for operatively engaging a plurality of battery holders which are removably supported on the belt. The power supply carrier uses conventional batteries to provide a DC voltage through the belt's wiring to a power output jack. Other more complex forms of the carrier may include a converter to supply a choice of DC and AC voltages either to multiple power outlets or to a voltage selector switch controlling a single output jack. An input terminal for re-energizing rechargeable batteries while connected to the power belt carrier also may be included. U.S. Pat. No. 5,211,321 teaches a battery and equipment vest, to be rechargeably used to provide power to video, recording, and like equipment. The battery and equipment vest which also provides numerous storage pockets, may utilize a battery belt or integrally disposed batteries and recharging equipment to provide a mobile, conveniently disposed power source, which may be recharged without removal from the vest. U.S. Pat. No. 5,929,597 teaches a portable power system configured to supply an appropriate voltage to an electrical device. The system includes a battery pack having at least one cell supplying a first direct current voltage, and an adapter. The adapter, which is electrically connected to the battery pack by an electrical cord, is configured to be mechanically connected to the device. The adapter also includes a DC to DC voltage converter supplying a second direct current voltage to the device, the second voltage being smaller than the first voltage but sufficient to permit the intended operation of the device. This particular patent discloses the use of a power drill that is powered using the batteries contained in the harness, which is to be worn by the user of the drill.
In any event, the propensity for carpal tunnel syndrome to manifest itself in a user of a hand-held power tool such as a drill is directly dependent upon the orientation of the drill during its routine use, as well as the overall mass of the drill itself Thus, if a convenient means for reducing the weight of the device were available, which rendered the user to maintain freedom from fixed power sources such as wall outlets or receptacles, such means would be useful in alleviating the propensity for carpal tunnel syndrome to manifest itself in workers using such tools.
SUMMARY OF THE INVENTION
The present invention is directed at a system for using a hand-held power implement which comprises a belt means, a pouch means having a re-chargeable battery, a hand-held electrical implement having a DC-operated motor, and a plurality of wires sufficient to convey electrical energy from the battery to the implement. Preferably, the implement includes a switch in its construction. The rechargeable battery may be selected from the group consisting of: nickel-cadmium, metal hydride, lithium, lithium ion, and rechargeable alkaline batteries.
According to another form of the invention there is provided a self-retracting cord reel disposed between the battery and the hand-held implement that contains and manages the wires so that excess slack in the wires does not pose a problem to the user. Another form of the invention includes a holster means disposed on the belt.
According to another form of the invention, the implement includes a handle portion having a bottom portion which further comprises a quick-disconnect electrical connector at the bottom portion. According to one preferred form of the invention, the hand-held implement is a drill.