Food slicer and associated blade sharpness evaluation system

Abstract

A food product slicer for slicing a food product includes a slicer body and a slicer knife mounted for rotation relative to the slicer body. A slicer cutter has a peripheral cutting edge with an associated cutting zone, and an associated cutter drive motor. The food tray is mounted to the slicer body for reciprocating movement back and forth past the cutting zone of the slicer knife. A blade evaluation system includes at least one vibration sensor positioned and configured to detect vibrations generated during sharpening of a microtome knife.

Description

Technical Field

[0001] This application generally relates to a food slicer of this type, which is commonly used for slicing bulk foods, and more specifically to a blade sharpness evaluation system in such a food slicer. Background Technology

[0002] A typical reciprocating food slicer features a rotatable circular or disc-shaped slicing blade, an adjustable gauge plate for defining slice thickness, and a support for the food as it moves back and forth across the blade's cutting edge during slicing. A drive motor can be connected to reciprocate the support during automated slicing operations performed by the slicer's controller. The gauge plate is positioned along the front of the blade's slicing stroke and is laterally movable relative to the blade to set the desired slice thickness. A rotatable adjustment knob or indexing mechanism is provided to set the spacing between the plane of the gauge plate and the plane of the blade, allowing the operator to select the desired slice thickness.

[0003] The blades of such a slicer need to be sharpened regularly to maintain good slicing performance. A sharpener is usually included in or integrated with the machine to allow the operator to sharpen the slicer blades.

[0004] It is difficult for operators to objectively determine whether a microtome blade needs sharpening. Experienced operators may clearly see that the blade is dull because the machine is not slicing as expected. However, by the time the operator makes this determination, it is often too late. It is also difficult to objectively determine when the sharpening process has been sufficiently and properly completed. To overcome these challenges, many operators either over-sharpen or under-sharpen. Over-sharpening often occurs to ensure that proper performance is always maintained, but this usually significantly shortens the blade's lifespan. Under-sharpening is usually due to the failure to perform frequent sharpening correctly (operator error or faulty sharpener) or because the operator is unaware that sharpening is needed.

[0005] Attempts to solve this problem focus on predicting when sharpening is needed by counting blade revolutions, product tray travel, or time, or by measuring the load on the machine (especially motor current). Several theories have also been proposed regarding how to automate the sharpening process. For example, U.S. Patent No. 8,220,383 (the entire contents of which are incorporated herein by reference) discloses a sharpener with a timed sharpening operation, in which slicer operating parameters (e.g., slicing travel) can be monitored, and a sharpening indicator (e.g., a light-emitting element) is triggered when the operating parameters reach a certain level (e.g., a set threshold number of slicing travels).

[0006] The drawback of prediction methods is that they are not very accurate. Predictions based on time, number of strokes, or blade revolutions ignore important variables in blade wear, namely the type of product being sliced ​​and the speed at which the product is sliced.

[0007] The drawback of the load measurement method is that it cannot accurately measure the load on the motor in a way that provides good data on blade efficiency. The load on the blade motor depends on the blade's sharpness, the force applied by the operator, and the type of product being sliced. Because this method cannot predict or measure the other two variables, it is difficult to obtain good data. Even if this data can be collected, and it is the only variable directly related to blade sharpness, it is only feasible to determine that its performance is declining after the blade has become very dull.

[0008] It is desirable to provide a slicer that can adequately determine one or more of the following: the sharpness of the blade, whether the blade needs sharpening, whether sharpening has been completed, and / or whether the blade has good / acceptable quality (or needs to be replaced). Summary of the Invention

[0009] In one aspect, a food slicer for slicing food includes: a slicer body; a slicer blade mounted to rotate relative to the slicer body, the slicer blade having a peripheral cutting edge with an associated cutting zone and an associated blade drive motor; and a food holder mounted to the slicer body for reciprocating movement through the cutting zone of the slicer blade. A blade evaluation system includes at least one vibration sensor positioned and configured to detect vibrations generated during slicer blade sharpening.

[0010] On the other hand, a method for performing a monitored sharpening operation in a food slicer having a slicing blade mounted for rotation, the slicing blade having a peripheral cutting edge, the method using a controller to: monitor a vibration signal output by at least one vibration sensor and evaluate the vibration signal to identify when a sharpening operation is in progress; when the sharpening operation is identified as in progress, evaluate the vibration signal to identify whether the peripheral cutting edge is sharp; and after determining that the peripheral cutting edge is sharp, trigger an output at a blade sharpness alert output terminal to convey to the user that sharpening should be stopped. This method can be performed in the aforementioned food slicer.

[0011] Details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will become apparent from the specification, drawings, and claims. Attached Figure Description

[0012] Figure 1 and Figure 2 A perspective view of a food slicer is shown; and Figure 3 A schematic block diagram of the various parts of the slicer is shown; Figure 4 and Figure 5 A perspective view of the slicer, including the sharpener, is shown; and Figure 6 A partial cross-section of a portion of the slicer is shown. Detailed Implementation

[0013] refer to Figures 1 to 6 The food slicer 10 includes a body or base 12 (e.g., housing 12a and / or cast base or base frame 12b) and a motor-driven circular slicing blade 14, which is mounted to the body to rotate about axis 16. Figure 2 The right-side view of the slicer is depicted. Figure 2 The left side (where the controls are located) is usually referred to as the front side of the slicer (i.e., the position where the operator stands when slicing). Figure 2 The right side is typically referred to as the rear side of the slicer. Food can be supported on a manually operated (or motor-driven) food carrier 20, which moves the food to be sliced ​​past the cutting edge 14a of the rotating slicing blade 14. The food carrier 20 reciprocates along a straight path 17, causing the lower end of the bulk food to slide along the surface of the gauge plate 22, be cut by the blade 14, and then slide along the blade cover plate 24. The food carrier 20 includes a tray 25 mounted on a tray arm 26, which is mounted on a conveyor 23 and orients the food carrier tray at an appropriate angle (typically perpendicular) to the plane of the blade cutting edge. The arms of the food carrier reciprocate in slots 28 at the lower part of the base 12. The carrier 20 can be moved manually (e.g., by a handle) and / or can be driven automatically (e.g., by an internal motor 30 that drives an internal belt connected to the arm 26 or the conveyor 23).

[0014] The gauge plate system includes a rotatable knob 40 (which connects to an opening in the base 12). Rotation of the knob 40 adjusts the distance between the plane of the gauge plate surface and the plane of the blade, allowing the operator to select the thickness of the slice to be produced.

[0015] The sharpening assembly 42 is mounted on the slicer. The sharpening assembly can take any suitable configuration. In some embodiments, the sharpening assembly can be detachable, or it can be a separate component not mounted to the slicer. For example, sharpening assemblies similar to those described in U.S. Patent No. 7,134,937 can be used.

[0016] The food slicer also includes a blade evaluation system that utilizes vibration sensors 50 (such as microphones (e.g., contact microphones) or accelerometers), an evaluation unit (part of controller 102) for processing data from the microphones or accelerometers, and a notification / interface for the operator. As used herein, the term "controller" is intended to broadly encompass any circuitry (e.g., solid-state, application-specific integrated circuits (ASICs), electronic circuits, combinational logic circuits, field-programmable gate arrays (FPGAs)), processor (e.g., shared, dedicated, or grouped hardware or software including code execution), software, firmware, and / or other components, or a combination of some or all of the above, that performs the control functions of the machine or any of its components.

[0017] This setup passively monitors the slicer. When the operator begins the sharpening process (i.e., one or more sharpening stone components of the sharpener are applied to the outer cutting edge of the rotating blade), the evaluation unit / controller will recognize that sharpening is in progress (based on vibration data output by vibration sensor 50) and begin evaluating the vibrations propagating through the machine to determine whether the sharpener is sharpening a dull blade or a sharp blade (e.g., by identifying vibrations consistent with known or stored vibration characteristics of a dull slicer blade, or consistent with known or stored vibration characteristics of a sharp slicer blade, characteristics that could previously be determined by testing and stored in memory).

[0018] In this implementation, the vibration sensor 50 is physically mounted to a portion of the slicer where frequencies below 20 kHz will not be significantly attenuated, as these frequencies are critical for assessing blade sharpness. The vibration sensor may be mounted, for example, to a portion of the slicer blade sharpener 42 (e.g., sensor 50a mounted to sharpener arm 42a, or each vibration sensor 50b or 50c mounted to the sharpener body) or to a mounting for the slicer blade sharpener (e.g., each vibration sensor 50d or 50e mounted to mounting 51). Alternatively, the vibration sensor may be located somewhere on or inside the slicer body (e.g., each vibration sensor 50f or 50g on an internal portion of the internal base frame 12b or housing 12a of the slicer body). Multiple vibration sensors in different locations may also be used.

[0019] Evaluation units / controllers used to process vibration signal data can utilize some form of hardware preamplifier or perform general filtering on the raw data from vibration sensors. The evaluation unit / controller can use frequency transformation (i.e., Fourier transform) to convert time-domain based data to frequency-domain based data. The evaluation unit / controller will analyze the data to distinguish between a dull knife being sharpened and a knife being properly sharpened. Many solutions and algorithms can be used to make this determination. This technique can involve using frequency analysis to examine the standard deviation of the inherent frequencies of sharp and / or dull knives.

[0020] The system can have a sleep mode and an active mode. In sleep mode, data is sampled periodically. In active mode, data is sampled at a faster rate and can be activated when the evaluation unit determines that sharpening is in progress.

[0021] The system provides real-time updates on the knife's status (dull or sharp), displayed on / at the operator's interface. When the operator initiates sharpening (by moving the sharpener into contact with the blade), the evaluation unit / controller determines whether the frequency curve indicates dullness or sharpness. If the operator begins sharpening and the knife is already sharp, the system recognizes that the appropriate sharpness has been achieved and alerts the operator that the knife is sharp. If the operator begins sharpening and the knife is dull, the system recognizes that the appropriate sharpness has not yet been achieved and continues to check the knife until the appropriate sharpness is reached. At this point, the system alerts the operator that the knife is sharpened.

[0022] The operator interface / output can be a simple LED 104 that illuminates during sharpening. This output can also include additional information provided alternatively via a display / screen 108 on the machine. Other possible forms of operator feedback include haptic feedback, sound (audio device 106), etc.

[0023] In one embodiment, controller 102 is configured to enable the detected sharpening operation, wherein the controller: (1) monitors vibration signals output by vibration sensors and evaluates these signals to identify when a sharpening operation has been initiated or is in progress (when the sharpening component of the sharpener has moved to contact the peripheral cutting edge of the blade); (2) when a sharpening operation is identified as being in progress, evaluates the vibration signals (e.g., compares the vibration signals with pre-stored signal characteristics, possibly using frequency analysis to examine the standard deviation of a specified frequency or multiple specified frequencies) to identify whether the peripheral cutting edge is sharp (i.e., sharpening can be stopped) or dull (i.e., sharpening should continue); (3a) if it is determined that the peripheral cutting edge is sharp, triggers a sharp blade alert output ( For example, a specific color LED is illuminated, a message is displayed on the screen (e.g., “Knife is sharp” and / or “Stop sharpening”) and / or a specific audio output is given, or (3b) if it is determined that the outer cutting edge is still dull, the sharpness warning output is abandoned and a dullness warning output may be given (e.g., a specific different color LED is illuminated, a message is displayed on the screen (e.g., “Knife is dull” and / or “Continue sharpening”) and / or a specific audio output is given). In this way, the slicer user can continue the sharpening operation until the knife is identified as sharp, and then stop sharpening to reduce the occurrence of undersharpening and oversharpening. During step (2), the controller may also evaluate the vibration signal to identify whether the outer cutting edge has reached the end of its cutting life.

[0024] This setup can also be used for other monitoring activities (besides monitoring blade sharpness). Appropriate analysis can easily allow for monitoring of other slicer systems. For example, if a bearing on the blade shaft fails, this will cause energy to increase at a frequency corresponding to the blade shaft's RPM. This system can be applied to every moving system or subsystem in the slicer. Pre-determining a specific frequency curve that will definitely lead to failure will allow the assessment unit to notify the operator of existing problems on the machine (i.e., bearing failure has begun or a call to maintenance is needed).

[0025] The system can also track sharpening time. Since passive monitoring will be able to determine whether sharpening is in progress, the machine controller 102 can determine the time spent sharpening and compare that time with a previously known or determined amount of time that indicates the limits of sharpening capability (e.g., the amount of time indicating that the knife may have been sharpened too much and is at the end of its life). The machine controller can then alert the operator that the knife has reached the end of its service life and should be replaced.

[0026] It should be clearly understood that the above description is for illustrative and exemplary purposes only, and not for limiting purposes. Variations are possible.

Claims

1. A food slicer for slicing food, comprising: Slicer body; A slicer blade, the slicer blade being mounted to rotate relative to the slicer body, the slicer blade having a peripheral cutting edge with an associated cutting zone and an associated blade drive motor; A food tray, which is mounted to the slicer body for reciprocating movement through the cutting area of ​​the slicer blade; A blade evaluation system, comprising at least one vibration sensor positioned and configured to detect vibrations generated during blade sharpening of a slicer.

2. The food slicer as described in claim 1, wherein, The blade evaluation system further includes a controller configured to evaluate vibration signals output by the at least one vibration sensor, wherein the blade evaluation system is configured to evaluate the vibration signals to identify the sharpness condition of the peripheral cutting edge.

3. The food slicing machine as described in claim 2, wherein, The controller is configured to identify the sharpness of the outer cutting edge when the vibration signal from the at least one vibration sensor indicates that the outer cutting edge is being sharpened.

4. The food slicing machine as described in claim 3, wherein, The controller is configured to preprocess the vibration signal before determining the sharpness of the peripheral cutting edge.

5. The food slicing machine as described in claim 2, wherein, The controller is configured to (i) identify when the peripheral cutting edge is being sharpened based on the vibration signal from the at least one vibration sensor, and (ii) provide a sharp blade alert output to remind the operator when the slicer blade is sharp.

6. The food slicer of claim 5, further comprising an audio output device, a visual output device, or a tactile output device for the controller to provide the sharpness alert output.

7. The food slicer as claimed in claim 5, further comprising: A sharpener, mounted on the food slicer, is used to sharpen the outer cutting edge.

8. The food slicing machine as described in claim 5, wherein, The controller is configured to identify whether the vibration signal is consistent with (i) known or stored vibration characteristics of a blunt slicing blade and / or (ii) known or stored vibration characteristics of a sharp slicing blade.

9. The food slicer as described in claim 5, wherein: The controller is configured to evaluate the vibration signal to determine a life-end condition indicating that the slicer blade has reached the end of its service life, and to provide a life-end reminder output to remind the operator that the slicer blade needs to be replaced.

10. The food slicing machine as described in claim 9, wherein, The food slicer includes an audio output device, a visual output device, or a tactile output device for the controller to provide the sharpness reminder output and / or the end-of-life reminder output.

11. The food slicer of claim 1, further comprising: A knife sharpener, mounted on the food slicer and including at least one sharpening component, the at least one sharpening component being movable to engage with the peripheral cutting edge for sharpening the peripheral cutting edge; The at least one vibration sensor includes a vibration sensor mounted on a part of the sharpener and / or on a mounting structure of the sharpener.

12. The food slicer as described in claim 11, wherein, The at least one vibration sensor includes a contact microphone or an accelerometer.

13. The food slicer as claimed in claim 1, further comprising: A knife sharpener, mounted on the food slicer and including at least one sharpening component, the at least one sharpening component being movable to engage with the peripheral cutting edge for sharpening the peripheral cutting edge; The at least one vibration sensor includes a vibration sensor installed inside the slicer body.

14. A method for performing a monitored sharpening operation in a food slicer having a slicing blade mounted for rotation, the slicing blade having a peripheral cutting edge, the method using a controller to: The vibration signal output by at least one vibration sensor is monitored, and the vibration signal is evaluated to identify when a sharpening operation is in progress; When the sharpening operation is detected, the vibration signal is evaluated to identify whether the outer cutting edge is sharp; When the outer cutting edge is determined to be sharp, the sharpness alert output is triggered to inform the user that sharpening should be stopped.

15. The method of claim 14, further comprising using the controller to: When it is determined that the outer cutting edge is not sharp, any sharpness alert output is abandoned and the dullness alert output is triggered to convey to the user that the knife should be sharpened.

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