This application relates generally to food product slicers of the type commonly used to slice bulk food products and, more specifically, to a food product slicer with an assist feature.
Typical reciprocating food slicers have a rotatable, circular or disc-like slicing blade, an adjustable gauge plate for determining the thickness of the slice and a carriage for supporting the food as it is moved back and forth past the cutting edge of the knife during slicing. A drive motor is typically linked to drive the carriage back and forth during an automatic slicing operation carried out by a controller of the slicer. The gauge plate is situated along the edge of the knife toward the front of a slicing stroke and is laterally movable with respect to the knife for determining the thickness of the slices to be cut. Many slicers also include a manual only mode, in which operator applied manual force, not the drive motor, causes the carriage to move back and forth for slicing. PCT International Application No. PCT/US2006/030066, published as WO 2007/021543, describes a slicer that includes a manual assist operation in which the carriage drive motor provides a level of assistance to the operator dependent upon a sensor (e.g., a force sensor) that detects force applied by the operator.
It would be desirable to provide a food product slicer with an assist function that is better adapted to provide a suitable level of assistance when needed.
In one aspect, a food product slicer includes a base and a knife mounted for rotation relative to the base via a knife drive motor. A carriage assembly is mounted to the base for reciprocal movement back and forth past a cutting edge of the knife via a carriage drive motor. An adjustable gauge plate is provided. During a manual assist slicing operation a level of assistance provided by the carriage drive motor varies according to loading on the knife motor.
Referring to
The illustrated position of the food carriage 56 is the most forward or front position relative to the slicer knife 54, typically the starting position for a slicing stroke. This position is also sometimes referred to as the home position of the carriage.
Repeatability of slice thickness is the control of slice thickness within a similar product, for example, if a particular machine slices ham at index setting of 4, on the adjustment knob, and that thickness is desirable, the next time a customer comes back to have more ham sliced and that if the index is set on 4 it will cut the same thickness. This theory will also apply from machine to machine repeatability. Prior techniques provided repeatability within a certain degree but not as consistent as desired. The machine to machine repeatability was generally not present.
Referring to
An exemplary slicer control system is illustrated in
The slicer may include both automatic and manual modes. During automatic slicing, the drive motor 204 moves the carriage back and forth past the slicer knife to repeatedly slice food product loaded on the carriage, with the thickness of slices determined by the open position of the gauge plate. During the manual mode, referred to herein as a manual assist mode, which may be selected by a suitable operator interface, the drive motor 204 is used to provide assistance to the operator as the operator moves the carriage. Specifically, the assistance provided by the drive motor 204 is dependent upon the load on the slicer knife motor 202. In one implementation, the knife motor current is monitored as an indicator of how much assistance to provide (e.g., to determine how much assistance (e.g., linear motor torque or more aptly linear motor force) is desirable to move the food carriage when actually slicing food product). This technique is truly an adaptive automatic assist to manual slicing. In another implementation some type of direct load sensor 212 associated with the knife motor (or alternatively the knife) could be used. In any case, the assistance level can be varied by, for example, varying the energization level and/or duration of motor coils associated with drive motor 204.
In one implementation, a two component assistance system is utilized to achieve a final or total assistance level provided by the drive motor 204. The first assistance component, also referred to as the baseline assistance torque or baseline assistance force, may be a fixed level of assistance and the second level provided by applying a set amount of current to the carriage drive motor 204. The set level may be provided in accordance with the weight of the carriage and the frictional force that resists movement of the carriage. In one variation the set level is the level of drive motor energization that falls just below a level required to cause the empty and stationary food product carriage to begin moving (e.g., as may be determined by testing or calculation). A set amount of motor torque or force is thus applied in the direction of travel (e.g., by first detecting movement direction of the carriage and then beginning to apply current to the drive motor in accordance with the first, fixed level). The amount of additional torque or force (herein referred to as load based torque or load based force) applied to the baseline assistance torque or force is determined by the loading on the knife motor 202, which may be represented by the amount of increased current usage by the knife motor as food product is being sliced (during front to rear carriage movement, i.e. a slicing stroke of the carriage) and the amount of force being applied to the surface of the knife by the food product passing over the knife (during rear to front carriage movement, i.e., a return stroke of the carriage).
In one implementation, the slicer control monitors the knife current draw and provides additional carriage drive motor current at a level proportional to the difference between the actual knife current draw and the nominal knife current (IACTUAL−IN), so long as the difference is a positive value. In one variation the additional drive motor current may be directly proportional to the difference, but other variations are possible. In another implementation, the additional torque or force or load based torque or force is only applied once the knife motor current draw reaches a set level above the nominal level (e.g., at least a level reflected by current IX).
While a two component assistance system is primarily described, it is recognized that a single component assistance system is also possible (e.g., one where carriage drive motor torque level does not include a baseline torque assistance component).
The described manual assist system is responsive to the type of food product being sliced (e.g., a cheese product will cause greater knife loading than a soft tomato) and is also responsive to operator action (e.g., the harder the operator attempts to move the food product past the slicer knife during slicing, the greater the knife loading). Accordingly, the contemplated manual assist feature is truly adaptive to the actual slicing conditions.
In one implementation of the manual assist, the carriage drive motor is not energized unless and until the knife drive motor is operating.
Referring back to
In some embodiments, assistance on product cut-through turnaround is provided. An amount of assistance is provided to an operator to aid in reversing directions of the carriage 56 after the product is cut through at the end of carriage travel. The amount of assistance is determined by the increase in current sensed when moving the product over the knife 54 on the previous return portion of a product slicing cycle. In other words, the turnaround torque or force assistance for given carriage movement cycle (shown in
As mentioned above, in some embodiments the assistance could be dropped to zero near the end of the slicing stroke and/or near the end of the return stroke. Referring to
In one example, when the carriage is determined to be outside of this home region (defined by distance D1), at least a baseline assistance FB may be automatically applied at all times. Thus, in a typical manual assist slicing operation starting from the home position of the carriage with the carriage moving away from the home position, assistance is zero for a set distance D1, assistance is raised to a baseline assistance level FB for a distance until a knife motor load increase is detected, at which point the additional knife load based assistance is applied until the food product has passed by the knife and the knife motor load again settles to nominal, at which point the baseline assistance alone is again applied.
In another example, even outside of the home region, the baseline assistance may be applied only when a determination is made that the speed of the carriage has reached a threshold minimum level. In this latter example, the assistance is set to zero both (i) whenever the carriage is determined to be within the home region (defined by distance D1) and (ii) whenever the carriage is moving at a speed that is below a threshold minimum speed.
Either of the two immediately preceding examples, could be adapted to include an end of slicing stroke turnaround assistance feature a previously described. Moreover, when the carriage is in the home region the carriage motor could also be energized in a manner tending to hold the carriage in the home region (e.g., resisting movement of the carriage). In the case of linear motor drive carriage this carriage hold feature could be achieved by applying a constant energization level to certain coils associated with the linear motor.
It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation. Variations are possible.
This application claims the benefit of provisional application Ser. No 61/085,139, filed Jul. 31, 2008 and Ser. No. 61/017,063, filed Dec. 27, 2007, the entirety of each of which is hereby incorporated by reference.
Number | Date | Country | |
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61017063 | Dec 2007 | US | |
61085139 | Jul 2008 | US |