Plastic Screwdriver With Retaining Ring

1. Field of the Invention

The present invention relates generally to a driver for screws or other fasteners, and more particularly to a hand-held driver which has a plastic shaft for receiving driving bits. The shaft includes a retaining ring adjacent to the bit receiving end. The handle includes bit holding slots having integral retention means for the bits.

2. Description of the Related Art

Devices for driving screws and the like are well known in the art, and have changed very little throughout the years. The typical driver, i.e., a screwdriver or nut driver, includes a handle, which is often made of plastic, and a metal shaft which extends from the handle. The shaft has a relatively small diameter so that the driver may be used in areas with limited access. The end of the shaft distal from the handle includes a hexagonal recess for receiving conventional driving bits. These types of bits are hexagonal on one end for being received by the driver, and include a driving end for installation and removal of the fastener to which the driving end corresponds. The driving bit may be, for example, a slotted, phillips or torx screwdriver, or a nut-driver bit.

Hand-held drivers of this type are shown, for example, in U.S. Pat. Nos. 4,227,430 and 4,924,733. The driving end of these types of drivers is subject to high torque forces. Thus, none of the drivers of this type employ a plastic or other nonmetallic shaft, since the torque at the driving end would likely cause premature failure of the shaft which would result in the bit stripping or cracking the shaft. This necessitates the use of a plastic handle with a metallic shaft and the increased cost of manufacture associated therewith.

U.S. Pat. No. 5,263,389 relates to a marine propeller wrench constructed of a plastic material impregnated with glass fibers. An annular reinforcing ring provides additional hoop strength to the socket portion. This device is constructed of relatively expensive materials to provide the necessary strength for a wrench, and as such is not practical for a mass-produced driver.

Drivers having handles for storing bits are also well known in the art. Such devices are shown, for example, in U.S. Pat. Nos. 3,683,984; 4,227,430; 4,434,828; 4,716,795; 4,924,733; 5,325,745; and 5,335,409. In these types of drivers, the handle of the driver typically includes several slots in which the driving bits are inserted. Retention means is provided for holding the driving bits within the slots. For example, in U.S. Pat. No. 4,434,828, sleeves of resilient material are press-fit into openings in the handle. U.S. Pat. No. 5,325,745 employs leaf springs which are used to hold the bits in the slots. U.S. Pat. No. 3,683,984 employs another type of spring to hold the bits in the slots. In U.S. Pat. No. 4,227,430, a portion of the handle may be rotated to expose the bits, which are stored within the handle. Finally, in U.S. Pat. No. 4,924,733, another type of spring mechanism is utilized.

In those patents in which a spring is utilized to hold the bit within each slot, the spring is a separate element from the handle. This increases the cost and complexity of manufacturing these drivers.

The present invention is a driver, preferably a hand-held driver, for use with removable driving bits, such as screwdriver or nut-driver bits. The driver includes a handle adapted to be hand-held, and a shaft. The shaft has a proximal end secured to the handle, and a distal end comprising a recess sized and shaped to enable a driving bit to be insertable therein and removable therefrom with a driving end of the driving bit extending from the shaft. A retaining ring (or ferrule) circumferentially surrounds the shaft toward the distal end and is closely sized thereto. The retaining ring has an open end adjacent to the distal end of the shaft having a size and shape corresponding to and aligned with the recess. The retaining ring (or ferrule) enables the shaft of the driver to be constructed of considerably weaker materials than was previously possible.

The handle and shaft are preferably each constructed of a thermoplastic, and are integrally constructed. The retaining ring is preferably constructed of stainless steel or another strong material.

Also disclosed is a handle for a driver, that includes one or more bit-receiving slots. Each slot is sized for enabling a driving bit to be slidably insertable therein and removable therefrom. Each slot includes resilient means integrally molded with the handle for providing frictional resistance to movement of the bit within the slot. This prevents the bit from falling out of the slot while still enabling insertion and removal of the bit from the slot. In one embodiment, the handle includes first and second portions adapted to be separably fitted together, the first portion attaching the handle to the shaft, the second portion incorporating the bit-receiving slots. In this embodiment, the handle and shaft are each constructed of a thermoplastic, and the first portion of the handle and the shaft are integrally constructed.

The resilient means is preferably either: A resilient arm which extends at least partially into the slot, whereby the resilient arm is laterally biased against a bit which is inserted into the slot; a resilient lip which applies frictional pressure to a bit inserted into the slot; or a resilient arm and a nub on the resilient arm that extends into the slot, wherein the resilient arm returns to a relaxed position after the insertion or removal of a bit.

More broadly, the invention may be embodied in any device which removably receives driving bits. The shaft has a first end for connection to a drive means for causing rotation of the shaft, and a second end distal from the first end which comprises a recess sized and shaped to enable the driving bits to be insertable therein and removable therefrom. The retaining ring circumferentially surrounds the shaft toward the second end and is closely sized to the outer diameter thereof.

The use of the retaining ring enables the shaft to be made of a plastic material and still have a diameter which is practical for use in areas with limited access.

FIG. 1 is a side view of a hand-held driver according to the present invention.

FIG. 2 is a top view of the hand-held driver shown in FIG. 1.

FIG. 3 is a side view of the handle and shaft of the driver of the present invention.

FIG. 4 is a cross-sectional side view through Section D--D of FIG. 10

FIG. 5 is a cross-sectional view through Section E--E of FIG. 10.

FIG. 6 is a partial side view of the handle and shaft of the invention from perspective "F" of FIG. 10.

FIG. 7 is a cross-sectional view through Section B--B of FIG. 3.

FIG. 8 is a cross-sectional view through Section A--A of FIG. 3.

FIG. 9 is a top view of the invention as shown in FIG. 3.

FIG. 10 is a cross-sectional view of the invention through Section C--C of FIG. 3.

FIG. 11 is a side view of one embodiment of the bit-storing cap of the invention.

FIG. 12 is a bottom view of the cap shown in FIG. 11.

FIG. 13 is a cross-sectional view of the cap through Section J--J of FIG. 15.

FIG. 14 is a cross-sectional view of the cap through Section K--K of FIG. 15.

FIG. 15 is a top view of the bit-storing cap shown in FIG. 11.

FIG. 16 is a cross-sectional view of the cap through Section H--H of FIG. 11.

FIG. 17 is a cross-sectional view (scaled 2:1) of the cap through Section G--G of FIG. 11.

FIG. 18 is a cross-sectional view of the cap through Section I--I of FIG. 11.

FIG. 19 is a side view of an alternative embodiment of a bit-storing cap.

FIG. 20 is a cross-sectional view through Section L--L of FIG. 19.

FIG. 21 is a cross-sectional view through Section M--M of FIG. 19.

FIG. 22 is a bottom view of the cap shown in FIG. 19.

FIG. 23 is a cross-sectional view of the retaining ring or ferrule through Section N--N of FIG. 24.

FIG. 24 is a top view of the ferrule shown in FIG. 23.

FIG. 25 is a cross-sectional side view of an alternative embodiment of the bit-storing cap.

FIG. 26 is a top view of the alternative embodiment of the bit-storing cap shown in FIG. 25.

FIG. 27 is a is a partial side view of the handle and shaft of the invention from perspective "R" of FIG. 26.

FIG. 28 is a cross-sectional view of the invention through Section P--P of FIG. 26.

FIG. 29 is a cross-sectional view of the invention through Section Q--Q of FIG. 26.

As shown in FIGS. 1-10, the present invention is a hand-held driver which includes a handle (5) integrally molded with a shaft (2). The shaft (2) has a proximal end (20), which is attached to the handle, and a distal end (22) for receiving driving bits. Handle (5) is shaped like a conventional screwdriver handle for being gripped by a human hand, and may have a hollow interior which can be utilized for storage, if desired. In the alternative, the device may be manufactured with a solid handle.

Handle (5) is preferably constructed of a plastic material, preferably a glass-coupled acetal filled celcon, a glass-filled polycarbonate, or a reinforced molded resin. Shaft (2) is preferably integrally molded with handle (5) and is constructed of the same plastic material. As shown in FIGS. 1 and 3-5, the distal end (22) of shaft (2) is adapted to receive a conventional driving bit (10). This end includes a hexagonal cutout (24) to receive conventional driving bits, such as screwdriver or nut-driver bits.

Located adjacent to the hexagonal cutout is a magnet cutout (26) in which a magnet (8) is mounted for magnetizing and holding driving bit (10). Magnet (8) enables driving bit (10) to hold screws and other fasteners, and is preferably a conventional rare earth magnet. It will be appreciated that magnet (8) is an optional feature of the invention.

A retaining ring or ferrule (28) circumferentially surrounds the distal end (22) of the shaft (2) at the portion of the distal end which includes hexagonal cutout (24). The diameter of the shaft at the driving end (22) is narrowed so as to form a lip (12) for enabling the retaining ring (28) to be secured thereon while not increasing the diameter of the shaft. Of course, the diameter of the shaft (2) could be continuous, with the retaining ring (28) then extending slightly outward from the shaft. The retaining ring (28) is closely toleranced to the outer diameter of the shaft and circumferentially surrounds the driving end (22) to prevent the driving end from cracking, breaking or stripping when subject to torque during use of the device. The retaining ring preferably extends above the portion of the shaft cutaway for the magnet and bit so as to provide additional strength and to reduce the likelihood of fracturing the plastic.

Retaining ring (28) includes a hexagonal cutout (100) also sized to receive conventional driving bits. The hexagonal cutout (100) is aligned with the hexagonal cutout of the shaft to enable the bits to be inserted into the shaft. The hexagonal cutout (100) on the retaining ring serves dual functions. First, it prevents the plastic material of the shaft from becoming distorted, i.e., squeezed out of shape due to the force between the bit and the retaining ring as torque is applied to the bit, which could result in fracturing of the plastic. Second, a portion of the driving force is absorbed by the hexagonal portion of the retaining ring, which also reduces the likelihood that the plastic will fracture.

Retaining ring (28) is preferably constructed of stainless steel, or any other metal of sufficient strength. It will be appreciated that the function of the retaining ring (28) is to prevent outward movement of the softer material which forms the driving end. Consequently, any suitable material which accomplishes this function may be used in lieu of stainless-steel.

In order to utilize the driver, a driving bit is inserted in the cutout (24) of the driving end (22). The device may then be used as a conventional driver. When torque is applied to the driving end (22), the retaining ring (28) prevents the driving bit (10) from stripping the plastic material of the driving end or otherwise breaking the end of the tool.

The function performed by the retaining ring may be adapted to power tools as well as hand tools. In this embodiment, a shaft has a first end for connection to a drive means for causing rotation of the shaft, and a second end distal from the first end comprises a recess sized and shaped to enable the driving bits to be insertable therein and removable therefrom. The invention is generally applicable to enable softer materials, including plastics, and die-cast and extruded metals to be used in tool construction by simply providing a high-strength retaining ring over the driving end of the tool. The invention also permits the handle and shaft of a driver to be integrally molded from an inexpensive plastic material. In addition to being less expensive to manufacture, a plastic driver is preferable for use in electrical work, since the plastic is electrically non-conductive.

As shown in FIGS. 11-22, a storage cap (30) is provided for being inserted into the top end of handle (5). Storage cap (30) is preferably constructed of a resilient plastic, rubber or other resilient material. Cap (30) includes resilient legs (32) which correspond with grooves (34) in handle (5) for enabling the cap to be properly inserted into the handle. A plurality of hexagonal slots (34), preferably three, are provided at the top of the cap for enabling the bits (10) to be stored therein. For each of the slots, a resilient arm (36) is provided which extends into the hexagonal slot (34). When a bit is inserted into the hexagonal slot (34), the resilient arm (36) applies pressure against the bit (10) to prevent the bit from sliding out of the slot. Handle (5) and cap (30) are shaped appropriately so that when the cap is inserted into the handle, it will be firmly retained therein. If desired, the hollow interior (38) of handle (5) maybe used for additional storage. In this instance, the cap maybe firmly secured to, but removable from, the handle (5). Resilient arms (36) are preferably integrally molded with the cap (30) to reduce manufacturing costs. It will be appreciated that any appropriate plastic material maybe used for the cap provided that the resilient arms perform the function indicated above.

In an alternative embodiment shown in FIGS. 19-22, in lieu of the resilient arms (36), one or more ridges (40) may be molded with the cap. The ridges (40) extend slightly into the hexagonal cutout (34), whereby when a bit is inserted into the cutout (34), ridges (40) provide sufficient frictional force for holding the bit (40) within the cutout while enabling removal of the bit without undue force. Thus, the present invention enables the construction of a one-piece cap for storing bits, including means for retaining the bits within the cap.

In a still further alternative embodiment, as shown in FIGS. 25-29, handle (5) includes resilient legs (102) for enabling the handle to be slidably inserted into the cap. Storage cap (30) is preferably constructed of the same material as handle (5), such as a resilient material, and ultrasonically welded, glued or affixed thereto by any conventionally known means.

As before, a plurality of hexagonal slots (34), are provided at the top of the cap for enabling bits (10) to be stored therein. For each of the slots, a resilient arm (106) is provided which extends generally parallel to hexagonal slot (34). Each resilient arm (106) includes a nub or protuberance (108) which extends slightly into hexagonal slot (34). When a bit is inserted into hexagonal slot (34), the bit applies pressure against nub (108), thereby biasing resilient arm (106) sufficiently to enable bit (10) to slide past nub (108). Once bit (10) is fully inserted into the slot, resilient arm (106) relaxes, causing nub (108) to slightly block the hexagonal slot. Nub (108) interacts with a shoulder (110) of bit (10) to prevent the bit from sliding out of the slot. Because the resilient arm returns to its relaxed position once a bit is inserted into the slot, any tendency of the resilient arm to lose its biasing force for holding bits in the slot is eliminated.

Although the present invention has been described in detail with respect to certain embodiments and examples, variations and modifications exist which are within the scope of the present invention as defined in the following claims.