Compound tools – With screwdriver
Reexamination Certificate
2000-02-15
2002-12-31
Morgan, Eileen P. (Department: 3723)
Compound tools
With screwdriver
C081S451000
Reexamination Certificate
active
06499168
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to tools, and, more specifically, to a drill adapter that includes, typically for alternating use, drill and driver bits and that embodies at least one efficient high energy permanent magnet for magnetizing the exposed tips of the screwdriver or other driver bits mounted on the drill adapter.
2. Description of the Prior Art
It is frequently desirable to magnetize the tips of screwdriver bits and the like to form at least temporary magnetic poles on the tips that attract magnetizable elements. Thus, particularly with precision screwdrivers that tend to be relatively small and are used to drive relatively small screws, it is frequently advantageous to magnetize the screwdriver tips of the driver bits to maintain the screwdriver tip blade within the slot of a head of a screw or a Phillips driver within the cross slots formed within the head of the screw adapted to receive the Phillips screwdriver tip. By magnetizing the tip of the driver bit, and mating the tip within the associated opening in the head of the screw, the screw remains attached to the bit tip without the need to hold them together. This allows the screw to be guided through a relatively small bore or channel and moved within confined spaces. Sometimes, the magnetized tip of the driver bit is used to retrieve a metal item, such as a screw, washer, nail or the like, from an inaccessible place that would otherwise be difficult to reach with anything but a relatively thin shank of a bit driver. Of course, such attachment of a fastener to the driver bit tip also frees one hand for holding or positioning the work into which the fastener is to be driven.
Devices for magnetizing/demagnetizing tools and small parts are well known. These normally incorporate one or more permanent magnets that create a sufficiently high magnetic field to magnetic at least a portion of a magnetizable element brought into its field. While the magnetic properties of all materials make them respondent in some way to magnetic fields, most materials are diamagnetic or paramagnetic and show almost no response to magnetic fields. However, a magnetizable element made of a ferromagnetic material readily responds to a magnetic field and becomes, at least temporarily, magnetized when placed in such a magnetic field.
Magnetic materials are classified as soft or hard according to the ease of magnetization. Soft materials are used as devices in which change in the magnetization during operation is desirable, sometimes rapidly, as in AC generators and transformers. Most bit drivers are made of magnetically soft materials that are not normally magnetized. In order for such bit drivers to exhibit magnetic poles they must be placed in a magnetic field. Hard materials are used to supply fixed fields either to act alone, as in a magnetic separator, or interact with others, as in loudspeakers and instruments.
Most magnetizers/demagnetizers include commercial magnets that are formed of either Alnico or are of the ceramic type. The driver members, on the other hand, are normally made of soft materials that are readily magnetized but more easily lose their magnetization, such as by being drawn over an iron or steel surface, subjected to a demagnetizing influence, such as heavy magnetic fields or other permanent magnetic fields, severe mechanical shock or extreme temperature variations.
One example of a magnetizer/demagnetizer is magnetizer/demagnetizer Model No. 40010, made in Germany by Wiha. This unit is in the form of a box made from plastic and forms two spaced openings defined by three spaced transverse portions. Magnets are placed within one of the transverse portions to provide magnetic fields, in each of the two openings that are directed in substantially opposing directions. Therefore, when a magnetizable tool bit or any magnetizable component is placed within one of the openings, it becomes magnetized, and when placed in the other of the openings, it becomes demagnetized. The demagnetizing window is provided with progressive steps to decrease the air gap for the demagnetizing field and, therefore, provides different levels of strengths of the demagnetizing field. However, typical magnetic materials that are used with conventional magnetizers/demagnetizers include Alnico and ceramic magnets that typically have energy products equal to approximately 4.5×10
6
gauss-oersteds and 2.2×10
6
gauss-oersteds, respectively.
Since the field strength B at the pole of the magnet is a product of the unit field strength and the area, and since the force of the magnet (H) is the product of the unit force (are the same unit field strengths) and the length of the magnet, it follows that the energy content or BH product is proportional to the volume of the magnet. It is for this reason that conventional magnetizers/demagnetizers have required bulky magnets having significant volumes to provide the desired energy content suitable for magnetizing and demagnetizing parts. However, the required volumes have rendered it impossible or impractical to incorporate the magnetizers/demagnetizers on the tools in conjunction with which they are frequently used. Thus, for example, precision screwdrivers, which are relatively small and have relatively small diameter handles could not possibly incorporate sufficient magnetic material to provide desired or required levels of magnetic fields for magnetizing and demagnetizing parts. However, the requirement of using separate magnetizer/demagnetizer units has rendered their use less practical. Thus, unless a user of a precision screwdriver or any driver tool obtained a separate magnetizer/demagnetizer, one would not normally be available for use. Additionally, even if such magnetizer/demagnetizer were available, it would require a separate component that could be misplaced and not available when needed. Of course, there is always the risk that the magnetizer/demagnetizer could become misplaced or lost, rendering the driver tool less useful.
A well known design of a magnetizable driver tool
10
is illustrated in
FIG. 1
, in which the handle
12
is provided with central axial channel
14
, which receives a portion
16
a
of a driver bit, leaving an external portion
16
b
exposed that has, at its free end, an operating tip
16
c
for driving, for example, a fastener. Another operative tip
16
d
is typically provided at the other end of the bit driver
16
which may be the same as or different than the operative tip
16
c.
In
FIG. 1
, the operative tip
16
c
is a screwdriver tip while the operative
16
d
is a Phillips driver. A chuck
18
may be used to selectively remove the bit driver
16
and reverse its direction to allow use of either one of the two operative tips or to replace the driver with another driver bit. In an effort to magnetize the bit driver
16
, and, more specifically, to provide a pole at the operative tip
16
c
that can attract a magnetizable fastener, there has typically been provided an in-line permanent magnet
20
arranged along the axis A of the tool with poles at
20
a
and
20
b
as shown. Such a magnet
20
gives rise to a magnetic field of the type illustrated and designated by the reference numeral
22
. However, as will be seen, such field
22
only partially interacts with the bit driver
16
, and primarily that portion of the driver
16
d
closest to the magnet
20
. Such magnetic field does not create a very strong magnetic pole at the operative tip
16
c.
In order to increase the strength of the pole, the size of the magnet
20
has been increased in order to enhance the magnetic field
22
. However, this rendered the magnet
20
relatively large in relation to the size of the handle
12
and significantly increased the weight of the tool. Even so, the degree of magnetic field coupling to the bit driver
16
, particularly to the exposed operative tip
16
c,
has remained low and thus the strength of the magnetic pole created at that end has remained relatively small.
Similar problems arise in conj
Danganan Joni B.
Lackenbach & Siegel LLP
Morgan Eileen P.
LandOfFree
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