CONTROLLABLE ELECTROMAGNETIC BENCH WORK PIECE HOLDER

PORTE-PIECE ELECTROMAGNETIQUE AJUSTABLE POUR ETABLI

English Abstract

The present invention relates to a material holding device using magnetic force of variable strength. The invention comprises an electromagnet mounted to a universal bracket that is adapted to mount to a vertical or horizontal surface. The electromagnet may also mount to a vise using the vise bar integrally attached to the underside of the magnet. The invention further includes a foot switch for on/off activation. A timer is provided to supply power for a predetermined amount of time only to prevent overheating of the magnet. The electromagnet has at least two selectable forces. The invention frees the hands of the user for speedy manipulation of the work piece.

French Abstract

La présente invention concerne un porte-pièce utilisant une force magnétique à intensité variable. L'invention comporte un électroaimant fixé à un support universel qui est conçu pour être fixé à une surface verticale ou horizontale. On peut également fixer l'électroaimant à un étau en utilisant la barre d'étau intégralement attachée à la face inférieure de l'aimant. L'invention comprend également un interrupteur au pied pour une activation ON/OFF. Un chronométreur est prévu aux fins d'alimentation électrique pendant une période prédéterminée, dans le seul but de prévenir la surchauffe de l'aimant. L'électroaimant comporte au moins deux forces sélectionnables. L'invention permet de libérer les mains de l'utilisateur pour une manipulation rapide de la pièce à travailler.

Claims

The embodiments of the invention in which an exclusive property or privilege
is claimed
are defined as follows:
1. A controllable electromagnetic bench work piece holder comprising an
electromagnet for temporarily holding a work piece, said electromagnet
disposed within a heat sink for dissipating heat generated by the
electromagnet, magnetic force control means electrically connected to the
electromagnet for varying the magnetic force thereof, a foot operated power
switch between a power source and the electromagnet, overheat protection
means for preventing the electromagnet from overheating and mounting
means for mounting the electromagnet to a work surface.
2. The holder of claim 1, wherein said heat sink comprises a circular housing
in
direct contact with the electromagnet.
3. The holder of claim 2, wherein said magnetic force control means comprises
a
magnetic force selector switch serially disposed between said foot operated
power switch and the electromagnet.
4. The holder of claim 3 wherein said magnetic force selector switch is
selectable between at least two force settings.
1

5. The holder of claim 1, wherein said overheat protection means comprises a
heat sensor disposed proximate to the electromagnet for detecting an overheat
condition, where said heat sensor is electrically connected to said foot
operated power switch for disconnecting power to the electromagnet during
said overheat condition.
6. The holder of claim 5, wherein the overheat protection means further
comprises a timed disconnect switch serially disposed between the foot
operated power switch and the power source for disconnecting the power
source from the electromagnetic following a predetermined amount of time.
7. The holder of claim 2, wherein said mounting means comprises a permanent
mount and a temporary mount.
8. The holder of claim 7, wherein said permanent mount comprises a mounting
bracket having a lower surface for mounting said circular housing, an upper
surface for said work piece placement and mounting tabs for mounting said
mounting bracket permanently to a work surface.
9. The holder of claim 7 wherein said temporary mount comprises a vise
clamping bar projecting from the circular housing for temporary clamping in a
vise.
2

10. A controllable electromagnetic bench work piece holder comprising an
electromagnet for temporarily holding a work piece, said electromagnet
mounted within a circular heat sink for dissipating heat generated by the
electromagnet, a magnetic force selector switch serially disposed between the
electromagnet and a power source for selection between at least two levels of
magnetic force, a foot operated power switch serially disposed between said
selector switch and said power source, an overheat protection sensor disposed
proximate to the electromagnet for detecting an overheat condition, said
sensor electrically connected to said foot operated power switch for power
disconnection during said overheat condition and a mounting bracket having a
lower surface for mounting said circular heat sink, an upper surface for said
work piece placement and mounting tabs for mounting said mounting bracket
permanently to a work surface.
11. The holder of claim 10, wherein the overheat protection means further
comprises a timed disconnect switch serially disposed between the foot
operated power switch and the power source for disconnecting the power
source from the electromagnetic following a predetermined amount of time.
12. The holder of claim 10 further comprising a temporary mount comprising a
vise clamping bar projecting from the circular housing for temporary
clamping in a vise.
3

Description

CA 02527339 2009-07-07
TITLE OF THE INVENTION
CONTROLLABLE ELECTROMAGNETIC BENCH WORK PIECE HOLDER
FIELD OF THE INVENTION
The present invention relates to a material holding device, specifically to
the
electromagnetic work holder, and more precisely to the controllable
electromagnetic
bench work piece holder.
BACKGROUND OF THE INVENTION
Particularly in the welding trade, steel and other materials of magnetic
attraction are most commonly used. Oftentimes, smaller pieces are difficult to
hold in
position so as to perform welding, cutting and grinding thereon. Clamps as
well as
large permanent magnets are commonly used to fix the pieces in place, and as
of late,
electromagnets are also being used to provide more ease of use. Additionally,
users
tend to simply hold work pieces with one hand and the tool in the other hand,
creating
a potentially dangerous situation. Unfortunately, electromagnets of this
magnitude
may become overheated if left active for a prolonged length of time.
Furthermore
current work magnets are of single strength and usually form part of a
complete work
surface.

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It became apparent to the inventor of the present invention to devise an
universal
bench magnet incorporating the valuable functions of magnetism, while
providing overheat-
protection means, a safer work piece holding means as well the liberty to
mount the bench magnet of
the present invention to virtually any bench, or even a vise.
While electromagnets have been used as a holding means in the past, prior art
teaches
of no such apparatus that provides user with all the benefits of the present
invention.
15

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SUMMARY OF THE INVENTION
It is thus the object of the present invention to provide users with an
universal bench
magnet incorporating the valuable functions of adjustable magnetism, while
providing overheat-
safety means, a safer work piece holding means as well as the liberty to mount
the bench magnet of
the present invention to virtually any bench, or even a vise.
In one aspect of the invention, the size of the bench magnet may be adapted to
suit
various industries.
In another aspect of the invention, the overheat-protection device may be that
of
either a timer or a heat sensor.
Accordingly, the universal bench magnet of the present invention allows users
to
safely free their hands from accurately holding work pieces, allow
repositioning of said work pieces
more speedily, adjust the magnetic force all while protecting said bench
magnet from overheating.
20

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BRIEF DESCRIPTION OF THE DRAWINGS
These and other advantages of the invention will become apparent upon reading
the
following brief description and upon referring to the drawings in which:-
FIGURE 1 is a perspective view from above of the universal bench magnet of the
present invention.
FIGURE 2 is a perspective view from above of the universal bench magnet of the
present invention shown holding a work piece.
FIGURE 3 is a front elevation view of the universal bench magnet of the
present
invention shown mounted onto a planar surface.
FIGURE 4 is a front elevation view of an alternative mounting of the universal
bench
magnet of the present invention shown clamped into a conventional vise.
FIGURE 5 is a front elevation view of an alternative mounting of the universal
bench
magnet of the present invention shown flush-mounted under a planar surface.
FIGURE 6 is a front elevation view of an alternative mounting of the universal
bench
magnet of the present invention shown mounted under a thin planar surface.
FIGURE 7 is a top plan view of the universal bench magnet of the present
invention
along with a brief schematic of the key operative components of the device.
While the invention is described in conjunction with preferred illustrated
embodiments, it will be understood that it is not intended to limit the
invention to such embodiments.
On the contrary, it is intended to cover all alternatives, modifications and
equivalents as may be
included within the spirit and scope of the invention as defmed by the
appended claims.

CA 02527339 2005-12-07
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In the following description, similar features in the drawings have been given
similar
reference numerals.
Turning to the drawings, in particular, Figure 1, a perspective view from
above of the
5 electromagnet portion of the universal bench magnet of the present invention
comprising: a housing
2 generally cylindrically shaped, a wound coil within said housing, mounting
tabs 3 having
perforations 4 therethrough and integral with the upper surface 14 of the
housing 2, an inner coil
coolant material, overheat protection means, and a vise clamping bar 8 fixedly
attached to the
bottom portion of the housing 2 and spanning generally equally to the diameter
of the housing 2.
Now turning to Figure 2, which illustrates a perspective view of the assembly
of the
universal bench magnet of the present invention comprising; an electromagnet
portion having a
housing 2, a wound coil within said housing, mounting tabs, an inner coil
coolant, overheat
protection means, and a vise clamping bar 8, a universal mounting bracket 12
comprising: an
electromagnet-attaching portion 14, and a bench attaching portion 16 having a
plurality of
perforations 17 therethrough to provide attaching means to a flat surface, a
control system
comprising: a power supply, an AC-DC transformer and rectifier, a current
fuse, a timer, a heat
sensor, an activating switch, and a power selector switch. When the foot-
switch is closed, enabling
the electroma.gnet, a work piece 6 can be held in a desired position then
easily released by opening
said foot-switch.
Turning now to Figure 3, a front elevation view of the universal bench magnet
of the
present invention as showed mounted onto a flat surface 5 using the universal
mounting bracket 12.
The universal mounting bracket 12 comprises: a top planar electromagnet-
holding portion 14
generally larger than the mating electromagnet, two vertically and downwardly
protruding side

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members extending equally or below the height of said electromagnet, and
horizontal mounting
flanges 16 extending from the lower portion of the vertical side members so as
to provide bench
connecting means.
Turning to Figure 4, further illustrating a front elevation view of the
universal bench
magnet of the present invention as shown mounted to a conventional bench vise
using the vise-
clamping bar 8 pressuredly inserted between vise jaws.
Turning now to Figure 5, illustrating a front elevation view of the universal
bench
magnet of the present invention showing an alternative mounting method of said
universal bench
magnet wherein the uppermost surface of the mounting bracket 12 is flush with
the upper surface of
the bench 5.
Turning to Figure 6, a front elevation view of the universal bench magnet
without the
universal mounting bracket wherein the electromagnet portion is securedly
attached to the underside
of a planar surface such as a steel work bench 5 via two recessed bolts 17.
Turning to Figure 7, a top plan view of the universal bench magnet of the
present
invention along with a brief schematic of the key operative components of the
device wherein the
electromagnet, mounted either to a bench surface using the universal mounting
bracket 12 with bolts,
or clamped into a vise jaw using the vise clamping bar, is powered and
controlled by means of the
following: household AC power outlets 20 feed a control panel adapted with a
fuse 21 then
transformed from AC to DC using a transformer and rectifier 22. A timer 23 is
activated once the
magnet is activated in the event the user forgets to turn the unit off. A
selector switch 25 allows the
user to select the magnetic force exerted by the magnet so as to allow easier
placement of work piece
prior to full-force holding. A foot switch 24 safely frees the user's hands to
activate the bench
magnet and perform work using both hands on the tool.

Representative Drawing