Patent Publication Number: US-2022217909-A1

Title: Device for Harvesting Bilberries

Description:
TECHNICAL FIELD 
     This invention relates to a device for harvesting bilberries. Bilberries are particularly delicate fruits and harvesting them must be carried out in such a way as to avoid impact and compression bruising, which leads to spoilage. Moreover, a bilberry plant has ripe and unripe fruits on it at the same time; if all the fruits are harvested, the ripe must be separated from the unripe after harvesting so the unripe ones do not reach market shelves. 
     BACKGROUND 
     Typically, small fruits are harvested using shaking tools including a vibrating hook configured to grasp and shake the branches of the plant so as to cause the fruits to drop. Tools for harvesting small fruits are described, for example, in the following patent documents: CN108353638A, CN108093865A, CN106358598A, CN103460904A, CN206181836U, CN 205232838U, US2013/199812A1, EP2624438A1, US2014/049204. 
     The hooks of prior art shaking tools have a variable oscillating frequency selectable by an operator through a frequency selector. To harvest the fruits, the operator grasps a branch of the plant with the hook, selects the vibration frequency suitable for that branch (that is, enough to make the ripe fruits drop off) and starts hook vibration; once the fruits have dropped, the hook is switched off and disengaged from the branch and the operation is repeated on another branch (after selecting the vibration frequency suitable for that other branch). The frequency must be suitable to make the ripe fruits drop but not the unripe ones (and is therefore not easy to identify and select). 
     That means each time the operator grasps a different branch, they must identify the frequency suitable for the branch, start the motor which drives the hook and, after finishing with that branch, must switch the motor off. This operation is complicated and takes time. In addition, the time needed for the operation is further prolonged by the mechanical inertia which the shaking hook is subject to, meaning that when the motor is switched off, the hook continues to vibrate for several seconds. Moreover, the prior art tools are heavy and cumbersome. 
     SUMMARY 
     The aim of this disclosure is to provide a device for harvesting bilberries and a method for harvesting bilberries to overcome at least one of the above mentioned disadvantages of the prior art. 
     This aim is fully achieved by the device for harvesting bilberries and by the method of this disclosure as characterized in the appended claims. 
     This disclosure relates to a device for harvesting bilberries. More generally speaking, this disclosure relates to a device for harvesting small fruits. For example, the device may be suitable for harvesting berries, and/or olives. 
     The device comprises a frame. The frame includes a handgrip portion (grippable by a harvest operator). Thus, the device is portable. 
     The device comprises a shaking unit. The shaking unit includes a hook-shaped portion (or hook) for grasping a branch of a bilberry plant. The shaking unit has a first end which is connected to the frame and a second end which includes the hook-shaped portion. The shaking unit is movable (or capable of oscillation) relative to the frame with reciprocating motion along an axis of vibration to shake the branch. 
     The device comprises a motor. The motor is associated with (or contained in) the frame. 
     The device comprises a transmission unit. The transmission unit is interconnected between the motor and the shaking unit. The motor is associated with the transmission unit to vibrate the shaking unit along the axis of vibration. More specifically, the vibration frequency is variable. 
     The device comprises a start and stop system. The start and stop system is drivable by an operator to send a start command and a stop command to the motor. More specifically, the start and stop system comprises a trigger. The trigger is located in proximity to the handgrip portion of the frame. That way, by gripping the handgrip portion, the operator can operate the trigger. Each time the operator passes from one branch to another, they stop and restart the motor through the start and stop system. 
     The device comprises a frequency adjustment system. The frequency adjustment system is drivable by the operator to select the vibration frequency at least between a first frequency and a second frequency. In an embodiment, the frequency adjustment system is drivable by the operator to select the vibration frequency from a plurality of frequencies. Thus, the vibration frequency is variable through the frequency adjustment system. 
     The frequency adjustment system is configured to keep the vibration frequency permanently set at the setting selected by the operator unless the frequency adjustment system is acted upon by the operator. In effect, it has been observed experimentally that the optimum oscillating frequency (which can make the ripe bilberries drop but not the unripe bilberries) is often the same for the branches of the same plant or of adjacent plants. Thus, once the operator has selected the optimum oscillating frequency for a certain plant or group of plants, they need not repeat the frequency selection operation each time they pass from one branch to another. 
     The frequency adjustment system is configured to keep the vibration frequency permanently set at the setting selected by the operator, independently on the operator acting on the start and stop system, for switching the motor on and/or off. Hence, the vibration frequency may be selected while the motor is off; then, when the motor is switched on, the shaking unit will start to vibrate at the selected vibration frequency. Moreover, the selected vibration frequency remains set even when the operator switches the motor off and, then, switches again the motor on; so, upon the motor being again switched on, the shaking unit starts vibrating at the pre-selected vibration frequency. 
     The frequency adjustment system is drivable by the operator independently of the start and stop system. Thus, the operator selects the frequency and that frequency remains set even when the operator stops and restarts the device. In an embodiment, the frequency adjustment system is distant from the start and stop system. 
     In an embodiment, the frequency adjustment system is configured to store the vibration frequency even after giving the stop command and/or the start command. 
     In an embodiment, the adjustment system includes an adjustment device which is settable at least at a first operating position and at a second operating position. The adjustment system is configured to keep the first frequency selected permanently, responsive to the adjustment device being set at the first operating position, and the second frequency selected permanently, responsive to the adjustment device being set at the second operating position. 
     In an embodiment, the device comprises a braking system, connected to the start and stop system and configured to dampen the vibration of the shaking unit in response to the motor being switched off through the start and stop system. That way, the operator does not need to wait for the effects of the mechanical inertia on the unit to diminish naturally before moving on to another branch. 
     In an embodiment, the motor is an electric motor. More specifically, the motor is a brushless motor. In this embodiment, the frequency adjustment system includes an electronic adjuster (or inverter) configured to regulate the electrical supply current of the electric motor. More specifically, the electronic adjuster is configured to supply the electric motor with a variable frequency electric current to vary the vibration frequency of the shaking unit, at least between the first frequency and the second frequency (or between a plurality of frequency values). 
     In an embodiment, the device comprises a battery. The battery may be associated with the frame or, more preferably, located in a backpack worn by the operator (the battery being connected to the frame by an electrical cable). The battery is configured to power the electric motor. In another embodiment, the device is configured to be connected to the electrical grid. 
     In an embodiment, the electronic adjuster is configured to reduce the frequency of the electric current to brake the motor responsive to the stop command being given. Thus, in an embodiment, the electronic regulator also defines the braking system. This solution also allows reducing electrical energy consumption. In another embodiment, the braking system includes a mechanical brake, connected to the shaking unit and controlled as a function of the stop command. 
     In an embodiment, the electronic adjuster is configured to vary the frequency of the electric current steplessly between a plurality of frequency values. In another embodiment, the electronic adjuster is configured to vary the frequency of the electric current in steps between a plurality of frequency values. 
     The adjustment system is configured to select the vibration frequency in a frequency interval between 1200 and 2200 oscillations (or cycles) per minute. In effect, it has been observed experimentally that in most bilberry plant branches, these are the optimum frequency values to shake ripe bilberries (but not unripe ones) off the branches. 
     The shaking unit has a stroke of less than 20 mm along the vibration axis. The length of the stroke is fixed. In an embodiment, the stroke is also greater than 12 mm. The stroke is less than 18 mm. Still further, the stroke is between 15 and 17 mm (for example, 16 mm). In effect, it has been observed experimentally that these are the optimum stroke values to shake ripe bilberries (but not unripe ones) off the branches. 
     In an embodiment, the transmission unit includes a link and crank mechanism. 
     In an embodiment, the transmission unit includes a slider crank mechanism (or slotted link mechanism). In particular, for slider crank mechanism (or slotted link mechanism) it is here intended a mechanism which transforms the rotative motion of a wheel (or gear) in a linear, alternative motion. The slider crank mechanism allows making the device lighter in weight. 
     In an embodiment, the shaking unit is adjustable to vary the size of the hook shaped portion. More specifically, the hook-shaped portion is curved (or angled) between a first end and a second end and is adjustable to vary the distance between the first end and the second end. That way, the device is adaptable to different types of bilberry plants (or other berry plants). 
     This disclosure also provides a method for harvesting small fruits. In particular, the small fruits can be: bilberries, berries and/or olives. 
     The method comprises a step of positioning a hook-shaped portion of a shaking unit around a branch of a small fruits plant (for example, a bilberry plant, or a berry plant, or an olive plant). 
     The method comprises a step of an operator selecting a vibration frequency of the shaking unit at least between a first frequency and a second frequency (or from a plurality of frequency values) using a frequency adjustment system. 
     The method comprises a step of starting a motor to vibrate the shaking unit along the axis of vibration at a vibration frequency. The step of starting the motor comprises a step of an operator giving a command to start the motor. 
     The method comprises a step of stopping the motor. The step of stopping the motor comprises a step of the operator giving a command to stop the motor. 
     The vibration frequency selected by the operator is kept permanently at the selected setting through a frequency adjustment system unless the frequency adjustment system is acted upon by the operator. More specifically, the vibration frequency selected by the operator remains set during the steps of starting and stopping the motor. 
     In an embodiment, the motor is an electric motor and the adjustment system sets the vibration frequency selected by the operator by adjusting a frequency of a motor supply current. 
     The step, of selecting the vibration frequency is carried out by the operator independently of the step of giving the command to start the motor and of the step of giving the command to stop the motor. 
     In an embodiment, following a step of giving a command to stop the motor, the method comprises a step of controlled braking of the shaking unit to dampen the vibration of the shaking unit. In an embodiment in which the motor is an electric motor, the step of controlled braking comprises a step of adjusting a frequency of a supply current of the electric motor. 
     In the step of selecting, the vibration frequency of the shaking unit is selected in a frequency interval between 1200 and 2200 oscillations per minute. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features will become more apparent from the following description of a preferred embodiment, illustrated by way of non-limiting example in the accompanying drawings, in which: 
         FIG. 1  shows a side view of a device according to this disclosure; 
         FIG. 2  shows a top view of the device of  FIG. 1 ; 
         FIG. 3  shows a lateral cross section of the device of  FIG. 1 ; 
         FIG. 4  shows a horizontal cross section of the device of  FIG. 1 ; 
         FIG. 5  shows the device during its operation. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to the accompanying drawings, the numeral  1  denotes a device for harvesting bilberries. 
     The device  1  comprises a frame  2 . The frame  2  is made, for example, of plastic material. The frame  2  comprises a handgrip portion  21 . The handgrip portion  21  can be used by an operator  91  to grip the frame  2 . More specifically, the operator  91  grips the handgrip portion  21  with one hand. 
     The device  1  comprises a shaking unit  3 . The shaking unit  3  is movable relative to the frame  2  with vibratory reciprocating motion along an axis of vibration A. The shaking unit  3  includes a hook-shaped portion  31 . The shaking unit  3  includes a rod  32 . The rod  32  extends along the axis of vibration A. The hook-shaped portion  31  is located at a free end of the rod  32 . 
     The hook-shaped portion  31  is configured for grasping a branch of a bilberry (or other small fruits) plant  93 . 
     More specifically, the rod  32  includes a first portion  321  and a second portion  322  which are detachably coupled to each other. The first portion  321  in turn extends between a first end  321 A and a second end  321 B. The hook-shaped portion  31  is connected to the first end  321 A of the first portion  321 . 
     The second portion  322  extends between a first end  322 A and a second end  322 B. The second end  321 B of the first portion  321 A is structured to be detachably coupled to the first end  322 A of the second portion  322 . 
     The detachable coupling of the first portion  321  to the second portion  322  allows dismantling the device  1  for transportation or storage. 
     The hook-shaped portion  31  comprises a first element  31 A and a second element  31 B connected to the rod  32  (specifically to the first portion  321 ). At least one (or both) of the first element  31 A and the second element  31 B is slidable along the rod  32  to vary a respective mutual position. That way, the distance between the first element  31 A and the second element  31 B is adjustable to vary the size of the hook shaped portion  31 . 
     The device  1  comprises an electric motor  4 . The electric motor  4  is located inside the frame  2 . In effect, the frame  2  defines a closed enclosure. 
     The device  1  comprises a battery (or battery pack) located in a backpack  92  wearable by the operator  91 . The device  1  comprises an electrical connecting cable to connect the backpack  92  to the frame  2  (hence to the electric motor  4 ). 
     The electric motor  4  comprises a rotary portion. The motor  4  comprises a pinion  41 , connected to the rotary portion. The pinion  41  is thus driven in rotation by the electric motor  4 . 
     The device comprises a transmission unit  5 . The transmission unit  5  is configured to transmit motion from the electric motor  4  to the shaking unit  3 . The transmission unit  5  comprises a slider crank mechanism (or slotted link mechanism)  50 . The transmission unit  5  (that is, the slider crank mechanism  50 ) comprises a slider element (or slotted link element)  51 , connected (or fixed) to the end of the rod  32  (specifically to the second end  322 B of the second portion  322  of the rod  32 ). The slider element  51  is slidable in a guide, with reciprocating motion along the axis of vibration A. The slider element  51  defines a slot inside it. The transmission unit  5  comprises a pin  52  which is slidable inside the slot in the slider element  51 . The transmission unit  5  comprises a first toothed wheel  53 , to which the pin  52  is fixed. The rotation of the first toothed wheel  53  causes the pin  52  to move within the slot and, at the same time, causes a movement of the slider element  51 , and thus of the rod  32 , along the axis of vibration A. 
     The transmission unit  5  comprises a second toothed wheel  54 , which meshes with the first toothed wheel  53 . The pinion  41  is fixed to the second toothed wheel  54  (specifically mounted internally thereof). Thus, the rotation of the pinion  41  is transmitted, through the second toothed wheel  54 , to the first toothed wheel  53  and to the pin  52 , which causes the slider element  51  to move in the guide along the axis of vibration A. 
     The transmission unit  5  also comprises rolling bearings  55  connected to the first toothed wheel  53  (to reduce friction during the rotation thereof). 
     The device  1  comprises a start and stop system  6 . The start and stop system  6  comprises a trigger  61  actuatable by the operator  91 . More specifically, the trigger  61  is in the proximity of the handgrip portion  21  so that the operator  91  can pull the trigger  61  while holding the handgrip portion  21 . The start and stop system  6  comprises a spring  62 , operable by pulling the trigger  61 . The start and stop system  6  is connected to the motor  4  to send it a start command and a stop command. More specifically, pulling the trigger  61  gives the start command and releasing the trigger  61  gives the stop command. Thus, the trigger  61  is movable between a pulled position, where it gives the start command, and a released position, where it gives the stop command. 
     The device  1  comprises a frequency adjustment system  7 . The frequency adjustment system  7  is located on the frame  2  at a position distant from the handgrip portion  21 . The frequency adjustment system  7  comprises a frequency increase control  71  and a frequency decrease control  72 . More specifically, the frequency increase control  71  and the frequency decrease control  72  are pushbuttons. The operator  91  increases the oscillating frequency by acting on (specifically by pressing) the frequency increase control  71 . The operator  91  decreases the oscillating frequency by acting on (specifically by pressing) the frequency decrease control  72 . 
     The device  1  comprises a shutdown control  8 . The shutdown control  8  is configured to power-off the device and deactivates both the start and stop system  6  and the frequency selection system  7 . The shutdown control  8  is also configured to power-on the device  1  and reactivates both the start and stop system  6  and the frequency selection system  7 . In an embodiment, the shutdown control  8  is located in proximity to the frequency selection device  7 . For example, the device  1  may comprise a keyboard including the shutdown control  8 , the frequency increase control  71  and the frequency decrease control  72 . The keyboard is located in an area of the device  1  distant from the trigger  61 . 
     This disclosure also relates to a method for harvesting small fruits (for example, bilberries, or berries, or olives). The method comprises a step of positioning a hook-shaped portion  31  of a shaking unit  3  around a branch of a small fruits plant  93  (for example, a bilberry plant, or a berry plant, or an olive plant). 
     The method comprises a step of an operator  91  selecting a vibration frequency of the shaking unit  3  at least between a first frequency and a second frequency through a frequency adjustment system  7 . More specifically, the operator  91  selects the oscillating frequency by acting on the frequency increase control  71  and the frequency decrease control  72 . 
     The method comprises a step of starting a motor  4  to vibrate the shaking unit  3  along an axis of vibration A at a vibration frequency. The step of starting the motor  4  comprises a step of an operator  91  giving a command to start the motor. More specifically, the operator  91  gives the start command by acting on a start and stop system  6  (that is, by pulling a trigger  61 ). 
     The method comprises a step of stopping the motor  4 . The step of stopping the motor  4  comprises a step of the operator  91  giving a command to stop the motor  4 . More specifically, the operator  91  gives the stop command by acting on the start and stop system  6  (that is, by releasing the trigger  61 ). Thus, the start and stop system  6  (that is, the trigger  61 ) is used to give both the command to start the motor  4  and the command to stop the motor  4 . 
     The vibration frequency selected by the operator  91  is kept permanently at the selected setting through a frequency adjustment system  7  unless the frequency adjustment system  7  is acted upon by the operator  91 . More specifically, the step, of selecting the vibration frequency is carried out by the operator  91  independently of the step of giving the command to start and stop the motor  4 . The vibration frequency selected by the operator  91  remains set during the steps of starting and stopping the motor. 
     Thus, following the step of selecting the frequency, the method comprises further steps of positioning, starting and stopping, repeated cyclically; during these steps, the frequency remains permanently set at the value initially selected by the operator. 
     The device  1  may also be provided with an indicator configured to show the operator  91  whether the tool (that is, the motor  4 ) is on or off. The indicator may be an illuminated (LED) indicator. The indicator may be located in proximity to the frequency increase control  71  and frequency decrease control  72  (on the keyboard). 
     The device  1  may also include an interface configured to show the operator  91  the selected frequency value (or a corresponding value on a scale). The interface may be located in proximity to the frequency increase control  71  and frequency decrease control  72  (on the keyboard).