Protection device adaptable for vertical blade cutters

Protection device adapted for use with a vertical blade cutter comprising a cutting blade. The device comprises a moveable plate for covering the blade and protecting against accidental contact with the blade. The moveable plate is adapted to be retracted during cutting and is further adapted to be otherwise lowered in front of the blade. A bar is provided which is adapted to slide in a guide adapted to be attached to the cutter. The moveable plate is mounted on the bar. A plate support is journaled onto the guide. A rotatable wheel is attached to the plate support. The rotatable wheel, when brought into contact with the bar while rotating, is adapted to raise the bar and moveable plate and whereas disengagement of the wheel from the bar causes the moveable plate to be lowered in front of the blade by virtue of its own weight and that of the plate.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a protection device adaptable for use with 
vertical blade cutters comprising a moveable covering and protection plate 
adapted to slide in a guide placed in front of the blade. The plate is 
adapted to retract from in front of the cutting blade by means of a 
driving device when the handle serving to direct the cutter is held. The 
plate automatically repositions itself when the handle is released and/or 
when the electric current is interrupted. 
2. Description of Prior Art 
The dangers associated with vertical blade cutters are known. To overcome 
these disadvantages cutters are provided with a moveable guard placed in 
front of the blades. These moveable guards are manually moved, which 
requires that the operator constantly think of lowering the guard when 
disengaging the machine, such as, for example to remove cut pieces. The 
type of manipulation results in a substantial loss of time and as a 
result, most often, the operator leaves the guard raised without even 
stopping the motor. On the other hand, when the protection guard is 
lowered, the blade is exposed since because of the cutter design, it 
protects the front face of the blade but not the sides. During various 
manipulations unrelated to the cutting, a very substantial danger may, 
therefore exist. 
SUMMARY OF THE INVENTION 
The invention has as an aim to minimize the various problems described 
above. 
The invention therefore has as an object a protection device adapted for 
use with vertical blade cutters comprising a moveable blade covering and 
protection plate attached onto a sliding bar in a guide vertically 
positioned and held on the cutter in front of the blade. The bar support 
plate is moved by means of a driving device so as to cause the retraction 
of the covering plate upon the simple contact of the hand during the 
gripping of the handle serving to direct the cutter. The release of the 
handle or the interruption of the feed current causes the systematic 
lowering of the covering plate in front of the blade.

As shown in FIGS. 1, 2, and 3, the protection device comprises a covering 
and protection plate 1 attached on a moveable bar 2 sliding in a guide 3 
attached to the cutter 4. The displacement of the bar 2 in the guide 3 
causing the retraction of the covering and protection plate is caused by a 
rubber wheel 5 biased against the bar 2. The wheel 5 is rotated by a 
motor-reducer 6 attached onto the support plate 7 journaled at 8 onto the 
guide 3. The activation of the motor-reducer 6 and as a result the 
retraction of the covering plate 1 occurs during the gripping of the 
handle 9 of the machine 4 which is used to direct the machine. This occurs 
through simple contact of human skin which activates the reel 10 provided 
with an electromagnet 13, coupled with the motor-reducer 6. The activation 
of the relay causes the motor-reducer to make contact and is caused when 
the two poles each constituted by a separate metallic wire, 11 and 12, 
embedded and wound helicoidally on the handle, are brought in contact by 
the simple contact of the human skin. The elevation and/or retraction of 
the covering plate 1 is stopped at the upper limit by means of a path 
ending not shown. When the handle is released and as a result connection 
between the two poles 11 and 12 is broken, the relay 10 is at rest and 
energizes the electromagnet 13 pushing armature 13a having the role of 
disengaging the rubber wheel 5 from the bar 2 by the simple action of a 
lever arm 14 journaled at 15 and shaft 16 supported on the guide 3. The 
shaft 6 is guided as shown in FIG. 2, causing the rotation of the support 
plate 7 thereby freeing the bar 2 which by virtue of its own weight and 
that of the covering plate 1, comes down to the lower dead point, a path 
end, not shown, serving to interrupt the voltage. The maintenance of the 
rubber wheel 5 against the bar 2 is caused by a return spring 17 
connecting the support plate 7 to the guide 3. 
According to another embodiment shown in FIGS. 4 and 5, the cover plate is 
lowered both when one releases the handle 9 as well as when one 
voluntarily cuts the current or if the current is cut involuntarily. The 
device is modified with respect to the electromagnet armature 13. In 
effect the armature is positioned oppositely, i.e., that when the 
electromagnet is energized only when one grips the handle 9, the armature 
13b compresses a spring blade 18 attached on the support plate 7 between 
the guide 3 and the electromagnet 13 which results in the freeing of the 
lever arm 14 and as a result causes the rubber wheel 5 to rest on the bar 
2. When the handle 9 is freed or when the electric voltage allowing the 
machine to operate is interrupted voluntarily or involuntarily, the 
electromagnet 13 is no longer energized, and on the contrary, the armature 
13b is biased by the spring blade 18 which causes the activation of the 
armature 13b on the lever arm 14 and as a result disengages the rubber 
wheel 5 from the bar 2 and from the coverplate 1. 
The device forming the object of the invention can be utilized in every 
case where a vertically displaceable mobile protection is necessary for 
vertical blade cutters as well as for all other machines whose use is 
dangerous.