Independent electrical implement system

[0001] 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.

[0002] 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.

[0003] 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.

[0004] 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.

[0005] 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.

[0006] 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.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] In the annexed drawings:

[0012] FIG. 1 shows a conventional drill according to the prior art;

[0013] FIG. 2 shows a perspective view of a system according to the invention; and

[0014] FIG. 3 shows a perspective view of a system according to the invention.

[0015] Referring to the drawings and initially to FIG. 1, there is shown a hand-held drill 10 according to the prior art. In this figure, the conventional drill is seen to comprise a drill housing 21, a handle portion 23 which handle portion has a bottom portion 25, and a battery 27. It is common in the art for the battery 27 to either protrude from the bottom portion 25, or in other embodiments to be wholly contained within the handle portion 23. In either case, however, the presence of such battery, while rendering the drill as a whole capable of use independent from its being electrically connected to an external power source, adds weight to the overall unit as a whole. This added weight means that the user must exert greater force on the drill to counteract the tendency of gravitational forces to move the drill in a position other than the position desired for drilling one or more holes. Since routine drilling operations generally require the drilling of holes in several orientations different from the direction at which the forces of gravity act, this means that the hand and wrist of the user of the drill will be required to exert a plurality of forces to counteract gravitational forces. The magnitude of the user's forces torque so required is dependent upon the distance at which the drill is disposed with respect to the user's center of gravity. The opportunities under such a scenario for carpal tunnel syndrome to become manifest are great, especially with prior art drills.

[0016] FIG. 2 shows a system according to one preferred form of the invention. In FIG. 2 is shown a belt means 33 that comprises clasps 37 and 39 which are complementarily engageable to one another, as such clasping means are well-known in the art. Attached to the belt using conventional means is a pouch 31, in which is contained a re-chargeable battery 41. There is a DC motorized drill 10 in electrical contact with both poles of the battery 41 by means of wires 29a and 29b.

[0017] FIG. 3 shows a system according to one preferred form of the invention. In FIG. 3 is shown a belt means 33 that comprises clasps 37 and 39 which are complementarily engageable to one another, as such clasping means are well-known in the art. Attached to the belt using conventional means is a pouch 31, in which is contained a re-chargeable battery 41. There is a DC motorized drill 10 in electrical contact with both poles of the battery 41 by means of wires 29a and 29b which pass through spring-loaded cord reel 35.

[0018] In either of the embodiments of the invention shown in FIGS. 2 or 3 the belt means 33 may be any belt known in the art which is affixable to a person's waist. Such belts include clasping means such as 37 and 39, which may be any clasping means known in the art. In these embodiments, the pouch portion 31 may be any construction which is capable of being attached to the belt 33 by conventional means such as rivets or other fasteners and having a sufficient interior volume to hold a battery 41. The battery is preferably a rechargeable battery, although this need not necessarily be the case. Rechargeable batteries are well known in the art and those suitable for use in the present invention include without limitation nickel-cadmium, metal hydride, lithium, lithium ion, and rechargeable alkaline batteries. The voltages of such batteries may be any voltage in the range of about 1.5 volts to 25 volts, and is selected depending upon the power requirements of the hand-held implement that is desired to be used.

[0019] The wires 29a and 29b are conventional wires which are connected to the positive pole and negative pole of the battery 41 at one of their ends, and to the drill 10 at their other ends. The drill 10 includes a switch means, as is well-known in the art.

[0020] According to one preferred form of the invention, there is a quick disconnect means at the point where wires 29a and 29b meet the battery 41 for the purpose of enabling the wires to be disengageable from the battery, so as to render the battery-containing belt to be a single unit without external wires attached. Similarly, according to another preferred form of the invention, there is a quick disconnect means at the point where wires 29a and 29b meet the drill 10 at its bottom portion 25 for the purpose of enabling the wires to be disengageable from the drill, so as to render the drill to be a single unit without external wires attached. Such quick disconnect means are well known in the art of electrical connectors, and any known two-pole electrical connecting pair is suitable for use in the present invention.

[0021] According to another aspect of the invention as shown in FIG. 3, there is a spring-equipped cord reel 35 which contains a portion of the wires 29a and 29b disposed between the battery and the drill 10. Such a cord reel is beneficial in reducing the amount of slack in the power cords 29a and 29b, (which may be individual members of a single 2-core wire) during use of the drill 10 by a workman, to reduce the propensity for snags of the wire(s) on corners or the feet of the user. Cord reels suitable for such use are known in the art and include those describe in U.S. Pat. Nos. 4,378,473; 4,384,688; and 4,713,497, the entire contents of each of which are herein incorporated by reference thereto.

[0022] According to an alternative form of the invention the belt means 33 may include a holster (not shown) that is adapted to receive the drill 10 for convenience of the wearer in having the system ready at hand, without actually holding the drill 10 in the hand.

[0023] A drill or other hand-held tool which is part of a system according to the invention may be used by a workman with greater confidence that prolonged use of such tool will not lead to carpal tunnel syndrome, owing to the fact that the tool is of greatly reduced weight in comparison to prior art rechargeable hand tools, which translates to less stress on the hands and wrist of its user. At the same time, a system according to the invention retains all the benefits of a cordless hand tool with respect to mobility and freedom of the workman from fixed power sources such as electrical receptacles, normally associated with the use of hand tools which do not comprise a built-in battery.

[0024] Consideration must be given to the fact that although this invention has been described and disclosed in relation to certain preferred embodiments, obvious equivalent modifications and alterations thereof will become apparent to one of ordinary skill in this art upon reading and understanding this specification and the claims appended hereto. Accordingly, the presently disclosed invention is intended to cover all such modifications and alterations, and is limited only by the scope of the claims which follow. As but one example, while this invention has been described and disclosed in relation to the use of a drill as a hand-tool, other electrically-operated hand tools such as hammers, saws, lamps, etc. are also useful in accordance with the invention.