Slicing machine with circular blade

A slicing machine in which the clamping device for pressing the product on the slicing machine carriage toward the stop plate is provided with a device for inactivating the blade motor and the drive for the stop plate so that, when the clamping device is in its upper inoperative position, the blade motor is deactivated and the stop plate is brought into the plane of the blade or forwardly thereof to prevent injury to an operator.

FIELD OF THE INVENTION 
My present invention relates to a slicing machine of the circular blade 
type in which a carriage is displaceable past a connecting edge of the 
blade and the stop plate against which the product to be sliced is set 
back from the blade edge by a drive and the blade is driven by a motor. 
More particularly, this invention relates to a slicing machine of this 
type which has a clamping or pusher device which can press the product 
toward the stop plate and which can be swung upwardly into an inoperative 
position. 
BACKGROUND OF THE INVENTION 
To protect an operator from injury with such a slicing machine it has been 
found to be desirable to shield the operator from contact with the blade 
or to cut off the motor drive. For this purpose switch arrangements can be 
provided which interrupt the supply of electric current to the blade motor 
as soon as the blade is uncovered, e.g. for cleaning purposes. 
The German patent document DE-A1 26 01 269 discloses a slicing machine 
which utilizes a switch as a protective device which must be separately 
actuated before the slicer is placed in operation by being actuated before 
each cutting operation. 
U.S. Pat. No. 4,123,959 and European patent document EP-A1 146,489 describe 
slicing machines which attempt to avoid injury by protective devices 
provided on the machine. 
There are slicing machines in common use and on the market in which the 
stop plate is set back to establish the slice thickness by the parallel 
spacing between the stop plate and the blade plane. There are also 
machines which determine the slice thickness by the stepping of the 
product in predetermined increments. In this case, the stop plate can be 
set back by an amount which is greater than the increment of advance of 
the product. For safety reasons in both cases, the set back of the stop 
plate only occurs immediately prior to or concurrently with the slicing 
operation so that the stop plate will lie in the blade plane prior to the 
cutting operation and is returned thereto after slice formation to shield 
the cutting edge of the blade against contact by the operator. 
OBJECTS OF THE INVENTION 
It is the principal object of the present invention to further increase the 
safety of slicing machines of the aforedescribed type. 
Another object of this invention is to provide a slicing machine in which 
the chances of injury to the operator are reduced without interfering with 
the ability to use the slicer in an efficient manner or to clean the 
slicer. 
SUMMARY OF THE INVENTION 
These objects are attained, in accordance with the present invention, by 
providing an electrical device for signalling the position of the clamping 
unit and, when the latter is swung into its upper or inoperative position, 
will reset the drive for the stop plate and de-energize or inactivate the 
blade motor, the stop plate being moved into an edge-shielding position. 
It has been found that the position of the clamping device on the machine 
is an especially advantageous criterion for the activation of the blade 
motor and the stop plate. When the clamping device is in its operative 
position, a product to be sliced is present between the clamping plate and 
the stop plate and it is difficult for injury to occur. When, however, the 
clamping device is swung upwardly or is in its inoperative position and no 
product is on the carriage, the blade is accessible to the hand of the 
operator and thus, in accordance with the invention, the stop plate is 
retracted to the blade plane and the blade motor is de-energized so that 
both the stop plate drive and the blade motor can only be energized when a 
product is on the carriage and is engaged by the clamping device. 
More particularly, the slicing machine of the invention can comprise: 
a slicing-machine bed; 
a slicing blade rotatable about an axis in a blade plane perpendicular to 
the axis and provided with a motor for driving the blade; 
a carriage for a product to be sliced displaceable on the bed transversely 
to the axis for slicing of the product as the carriage is moved past a 
cutting edge of the blade; 
a stop plate mounted on the bed, disposed alongside the blade and shiftable 
on the bed between a slicing position wherein the plate is set back from 
the blade by a distance of at least a slice thickness and a shielding 
position wherein the stop plate is disposed forwardly of the slicing 
position and shields the edge against injury to an operator; 
a drive for shifting the stop plate between the positions; 
a clamping device swingable between an operative lower position wherein the 
device urges a product on the carriage against the stop plate and an 
inoperative upper position; and 
means for detecting a position of the device for inactivating the drive and 
the motor in the upper position of the device. 
Advantageously, the signalling system can comprise a magnetic strip which 
extends in the direction of carriage displacement below the carriage and 
at least one reed contact on the machine housing below the magnetic strip, 
the magnetic strip being retracted from a position in which it can operate 
the switch to signal one or the other of the positions of the clamping 
device. It has been found to be advantageous to provide the swingable arm 
of the clamping device with a projection or cam which can cause the 
magnetic strip to be drawn away from the reed switch upon displacement of 
the clamping device into its upper inoperative position. 
The magnetic strip can have a length which enables the reed switch or a 
group of reed switches spaced by less than the length of the magnetic 
strip or a distance substantially equal to this length so that at least 
one reed switch is affected by the magnetic strip independently of the 
position of the carriage along its path. 
If the magnetic strip is raised, e.g. by swinging of the clamping arm into 
its upper position, the reed switch opens to prevent energization of the 
stop plate drive and the blade motor. 
When the magnetic strip lowers, the reed contacts can be closed. The reed 
contacts are in circuit with the blade motor and the positioning drive or 
the stop plate and can reset the stop plate into the plane of the blade 
when the clamping device is raised. The blade motor also cannot operate in 
this condition. 
The linkage between the magnetic strip and the clamping device can be 
mechanical levers, rods or cams. A bar can, for example, be interposed 
between the arm and the magnetic strip or a cam and cam follower stem can 
be used for this purpose. 
It has been found to be advantageous to provide a plurality of reed 
contacts along the path of the slicing carriage, thereby permitting the 
length of the magnetic strip to be reduced. It is sufficient that the 
magnetic strip be capable of bridging two such reed switches. 
To enable the machine to be more readily cleaned, the carriage can be swung 
about an axis parallel to its displacement, thereby moving the magnetic 
strip away from the reed switch or reed switches and ensuring in this 
cleaning position that the motor will be cut off and the drive for the 
stop plate in the position in which the stop plate shields the cutting 
edge of the blade.

SPECIFIC DESCRIPTION 
A slicing machine according to the invention can comprise, as is customary, 
a pushing or clamping device 1 which engages the comestible product to be 
sliced, e.g. a sausage represented at 8, for advancing that product toward 
a stop plate 5 on a carriage 3 which is displaceable back and forth 
transversely to the axis of rotation of a circular blade 2 driven by a 
motor represented at 30 in FIGS. 1 and 2. In FIG. 1, the clamping device 
1, with its pusher plate 31 mounted on the arm 7 is shown in its operative 
position in which it is juxtaposed with the stop plate 5 and the food 
product 8 is received between the plates 5 and 31. 
In FIG. 2, the plate 31 of the clamping device 1 is shown in its raised or 
upper position, i.e. in the open or inoperative position, allowing the 
food product to be placed upon the carriage 3 or removed therefrom. The 
pivot motion of the plate 31 is represented by the double-headed arrow 32 
while the pivotal motion of the arm 7 upon which the plate 1 is mounted is 
represented by the double-headed arrow 33. The axis of the blade 2 is 
represented at 34. In the position shown in FIG. 2 the blade 2 is 
accessible. 
In this latter position, the blade 2 poses a danger to the operator when 
the thickness of the slice to be cut is sufficiently great that the plate 
5 is shifted out of the plane of the blade 2 by an amount enabling the 
operator to contact the cutting edge 35 of the blade. It will be 
understood that in a slicing machine of this type, the plate 5 is adjusted 
relative to the plane of the cutting edge 35 and perpendicular to the 
plane of the paper in FIGS. 1 and 2 by at least the thickness of the slice 
or to establish that thickness. 
The carriage 3 is displaceable along a machine bed 4 perpendicular to the 
axis 34 and along the adjustable stop plate 5 back and forth as 
represented by the double-headed arrow 9. On the carriage 3 a bar 6 is 
mounted which extends parallel to the axis 34 and perpendicular to the 
plane of the paper in FIGS. 1 and 2. 
The arm 7 is mounted to slide along the bar 6 perpendicular to the plane of 
the paper and to swing upwardly and downwardly between the positions shown 
in FIGS. 1 and 2 as represented by the arrow 33. The arm 7 extends over 
the loading region of the carriage 3 and carries the pusher plate 1 
previously described which urges the product 8 to be sliced against the 
stop plate 5. 
Consequently, with the blade 2 rotating, the plate 5 set back from the 
plane of the edge 5 by the thickness of the slice, the plate 1 in the 
position shown in FIG. 1, a manual displacement of the carriage 3 or the 
displacement of the carriage 3 by a drive in the direction of the arrow 9 
back and forth, while the plate 31 is pressed toward the plate 5, will 
result in the slicing of the product 8 to form a number of slices in 
succession which may have different thicknesses, depending upon the 
adjustment of the plate 5, a typical slice thickness being about 2 mm. In 
that case, the stop plate 5 is set back from the plane of the blade 2 by 2 
mm. During this operation, the arm 7 is in the position shown in FIG. 1 
and slides along the bar 6 in the direction of the stop plate 5. 
The arm 7 is provided with a projection or nose 10 which, upon swinging of 
the arm into its upper position, engages a swingable strip 11 to displace 
this strip about its axis 12 in the counterclockwise sense (compare FIGS. 
1 and 2) into the position shown in FIG. 2. The strip 11 is connected by a 
link 13 with a magnetic strip 14. 
The magnetic strip 14 is mounted on the carriage 3 for displacement 
therewith parallel to the machine bed 4 back and forth with the carriage. 
Toggle linkages 15 or the like connect the magnetic strip 14 with the 
carriage and the magnetic strip 14 is braced by the springs 16 toward the 
position shown in FIG. 2 in which the magnetic strip 14 is at a maximum 
distance from the carriage. The toggle linkages 15 and the spring 16 are 
provided in pairs so that the magnetic strip 14 is moved parallel to 
itself when it is pulled up by the link 13 (see FIG. 2). 
The magnetic strip 14, when it approaches the bed 4, is juxtaposable with 
reed switches 17 and 18 provided on the machine bed. These reed switches 
contain contacts which are normally open but close in the presence of the 
permanently magnetic strip 14. 
The reed contact 17 in FIG. 1 is therefore closed since the magnetic strip 
14 is in its lower position into which it is braced by the springs 16 in 
the absence of engagement by the projection 10 of the pivotal strip 11. 
The circuit 19 is energized controlling the drive 20 for adjustment of the 
plate 5 and back and forth displacement of the carriage 3, the stop plate 
5 being shifted out of the plane of the blade for each slicing operation 
before the product 8 reaches the edge 35 and being returned to the plane 
of the blade when the product 8 is again shifted to the left after a slice 
has been formed. 
The switch 17, in its closed position, also allows energization of the 
control circuit 21 for the motor drive 22, i.e. the controller of the 
motor 30. 
As a consequence, the circuits 19 for the thickness adjustment drive 20 and 
the controller 21 for the motor system 22, 30 can only be energized while 
the reed switch 17 is closed. 
When the carriage 3 is moved into the position shown in broken lines in 
FIG. 1, the strip 14 approaches the previously open reed contact 18 an 
closes the latter before leaving the reed contact 17 sufficiently to allow 
it to open. The voltage is then applied to the controllers 21 and 19 
through the now closed reed switch 18. 
When, however, the clamping device 1 is raised (FIG. 2) the projection 10 
engages the strip 11 and rotates it about the pivot 12, thereby drawing 
the link 13 upwardly and raising the strip 14. The magnetic field of the 
strip 14 can no longer close the reed contacts 17 and 18 so that these 
remain open even if the carriage 3 is displaced back and forth over the 
reed contacts 17 and 18. 
Opening of the reed contact 17 and 18 de-energizes the controller 19. 
Failure of the signal at 19 causes the stop plate 5 to shift from its 
cutting position into the plane of the blade (zero cutting thickness or 
set back) to shield the edge 35 of the blade. The stop plate 5 can also be 
positioned ahead of the blade plane (negative slice thickness) if desired 
to shield the blade edge. 
The control 21 likewise receives no signal so that the motor system 22, 30 
is shut down and the usual blade brake can prevent overrunning of the 
blade. 
When the carriage 3 is shifted in the open position of the clamping device 
1, the magnetic strip 14 remains in its retracted position so that the 
reed switches 17 and 18 cannot be closed. This, of course, provides 
maximum reliability against injury from the slicing machine. 
When the carriage 3 is swung out about the axis 23 from the plane of the 
paper for cleaning purposes, the magnetic strip 14 is also removed from 
any possibility of approach to the reed switch 17 and 18 so that the blade 
motor system 22, 30 is switched off or cannot be switched on, and the stop 
plate 5 will assume its protective position in the blade plane or ahead of 
the latter. This effect is also of special significance from a safety 
point of view.