Snowblower

Abstract

To provide a snow remover capable of automatically lifting and lowering a snow removing part without using a tilt angle detection sensor or an acceleration sensor.SOLUTION: A control part 60 has a lifting timer 61 to control lifting of a snow removing part and a lowering timer 62 to control lowering of the snow removing part, and controls lifting and lowering of the snow removing part by the lowering timer 62 and the lifting timer 61 by completing lifting of the snow removing part when a lifting time counted by the lifting timer 61 reaches a target lifting time and by completing lowering of the snow removing part when a lowering time counted by the lowering timer 62 reaches a target lowering time.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a snow removal machine that reduces the burden on an operator by automatically lifting a snow removal unit upward during reverse travel during snow removal work. In the following description, "lifting" is a term that combines "ascending" and "descending".

Background Art

[0002] Snow removal is important in snowy regions. Since manual snow removal is laborious, the introduction of a snow removal machine is desired.

[0003] A snow removal machine includes a traveling unit that travels on a road surface and a snow removal unit that removes snow on the road surface. The snow removal unit is attached to the traveling unit so as to be able to move up and down. When performing snow removal work by repeating forward and reverse travel, during reverse travel, the snow removal unit is sufficiently separated from the road surface so that the snow removal unit does not hit the accumulated snow. Therefore, the operator repeatedly lowers the snow removal unit during forward travel and raises the snow removal unit during reverse travel. This lifting is performed by operating a snow removal unit lifting lever.

[0004] In addition to the lifting operation of the snow removal unit, the operator also performs operations such as adjusting the traveling speed, operating forward and reverse, and controlling the snow removal direction. Therefore, there are many operation items. Therefore, for the purpose of reducing the burden on the operator, technologies for automating the lifting of the snow removal unit have been proposed (see, for example, Patent Document 1 and Patent Document 2).

[0005] Patent Document 1 relates to a snow removal machine, and this snow removal machine includes a sensor (specifically, a tilt angle detection sensor) that detects the tilt angle of a vehicle body frame corresponding to the snow removal unit. The operator sets a target tilt angle.

[0006] During reverse travel, the snow removal unit automatically ascends until the tilt angle measured by the tilt angle detection sensor reaches the target tilt angle. During forward travel, the snow removal unit is automatically lowered. Since the position is monitored by the tilt angle detection sensor, the snow removal unit is returned to its original position (height).

[0007] Patent Document 2 relates to a snowblower, which is equipped with an acceleration sensor in the auger housing corresponding to the snow removal section. The tilt angle (inclination angle) of the auger housing is calculated based on the acceleration detected by the acceleration sensor.

[0008] Similar to Patent Document 1, when reversing, the snow removal unit automatically rises until the inclination angle measured by the acceleration sensor reaches the target inclination angle. When moving forward, the snow removal unit is automatically lowered. Because its position is monitored by an acceleration sensor, the snow removal unit is returned to its original position (height).

[0009] As described above, snowblowers that automatically raise the snow removal unit when reversing are equipped with tilt angle detection sensors and acceleration sensors to measure the inclination of the snow removal unit. Tilt angle detection sensors and accelerometers are precision instruments and are therefore expensive. In addition, when snow removal components such as augers bite into snow (especially frozen snow), they experience a large reaction force. This reaction force is an impact force. Precision instruments are affected by impact and become misaligned. This misalignment is "calibrated" periodically or as needed.

[0010] During calibration, snow removal operations are interrupted, reducing efficiency. Calibration also increases maintenance costs. Reduced work efficiency and increased maintenance costs are hindering the widespread adoption of snowplows with automatically raising and lowering snow removal units.

[0011] Therefore, there is a need for a snowblower that can automatically raise and lower the snow removal unit without using tilt angle detection sensors or acceleration sensors. [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] Patent No. 4319437 [Patent Document 2] Patent No. 6040139 [Overview of the project] [Problems that the invention aims to solve]

[0013] The present invention aims to provide a snowblower that can automatically raise and lower the snow removal unit without using tilt angle detection sensors or acceleration sensors. [Means for solving the problem]

[0014] The inventors of this invention discovered the following during their investigation of snow removal operations using snowplows. Snow conditions vary from place to place. Snow conditions include factors such as snow height, density, and moisture level. Experienced snow removal workers adjust the height of the snow removal unit according to the snow conditions. Even with snowblowers where the snow removal unit automatically returns to its original position when moving forward, the height of the unit is finely adjusted once it returns to its original position. This fine adjustment is frequent.

[0015] The inventors discovered that if the height can be finely adjusted, it is not necessary to return the snow removal unit to its original position precisely; it is acceptable to return it to an approximate position. Based on this discovery, they completed the invention described below.

[0016] The invention according to claim 1 comprises a running unit that travels on the road surface powered by a drive source, A snow removal unit is tiltably mounted on this travel unit to remove snow accumulated on the road surface, A travel control element that switches between forward, neutral, and reverse positions to move the travel unit forward, stop, or reverse, The system includes a control unit that acquires switching information for the position of the travel control unit, and performs control to raise the snow removal unit when the travel control unit is switched from the neutral position to the reverse position, and to lower the snow removal unit when the travel control unit is switched from the reverse position to the forward position via the neutral position, A snowblower that reduces the burden on the operator by automatically raising the snow removal unit when reversing and automatically lowering the snow removal unit when moving forward during snow removal work, The control unit includes a rising timer for controlling the rising of the snow removal unit and a falling timer for controlling the falling of the snow removal unit. When the rising time counted by the rising timer reaches the target rising time, the rising of the snow removal unit is completed, and when the falling time counted by the falling timer reaches the target falling time, the falling of the snow removal unit is completed. Thus, the falling timer and the rising timer control the raising and lowering of the snow removal unit. In order to If the travel control is switched to the neutral position or the forward position before the rise time counted by the rise timer reaches the target rise time, the target descent time is replaced with a value obtained by the formula (rise time counted by the rise timer immediately before) × (a value less than 1.0). It is characterized by this.

Effect of the Invention

[0018] In the invention according to claim 1, the falling timer and the rising timer are used to control the raising and lowering of the snow removal unit. The falling timer and the rising timer may be timer circuits incorporated in a control circuit in addition to independent devices. The cost increase due to providing the timer is slight, and the price increase of the snow removal machine is suppressed.

[0019] In addition, the timer will not go out of order even if it is subjected to impact and does not need to be calibrated. There is no need to interrupt the snow removal operation for calibration, and the efficiency of the snow removal operation is improved. As a result, according to the present invention, a snow removal machine capable of automatically raising and lowering the snow removal unit without using a tilt angle detection sensor or an acceleration sensor is provided.

[0020] In addition, Claim 1 In the invention according to this, the target falling time is replaced with a value obtained by the formula (rising time counted by the rising timer immediately before) × (a value less than 1.0).

[0021] By multiplying by (a value less than 1.0), the target falling time is set shorter than the target rising time. Due to the action of gravity, the snow removal unit rises slowly and falls quickly. By setting the target falling time shorter than the target rising time, the snow removal unit at the time of falling can be returned to the height at the start of rising.

[0022] The target descent time is not a fixed value, but rather a value (variable value) that is corrected based on the value of the rise time (counted by the rise timer immediately beforehand). In other words, the target descent time is constantly adjusted using the formula: measured rise time × correction coefficient.

[0023] By the way, when the snow removal unit is always raised for a target time, the target descent time can be a fixed value. However, if the snow removal unit is interrupted during its ascent, it cannot be automatically lowered based on the target descent time. This is because the unit will descend too far. In this case, it is necessary to deactivate the automatic mode and lower the snow removal unit manually.

[0024] In contrast, in this invention, the target descent time is replaced with a value obtained by the formula (ascending time counted by the ascending timer immediately beforehand) × (a value less than 1.0). Therefore, even if the ascending operation is interrupted while the snow removal unit is ascending, the target descent time is adjusted to match the height immediately before the interruption, and the automatic mode is maintained. [Brief explanation of the drawing]

[0025] [Figure 1] This is a side view of a snowblower according to the present invention when the snow removal unit is at its upper limit. [Figure 2] This is a side view of a snowblower when the snow removal unit is at its lowest position. [Figure 3] This is a plan view of a snowblower. [Figure 4] A plan view of the control panel. [Figure 5] This is a view from arrow 5-5 in Figure 4. [Figure 6] These are diagrams illustrating the operation of the driving controls; (a) shows the operation of reverse movement, and (b) shows the operation of forward movement. [Figure 7] (a) is a graph showing the correlation between the rotation angle of the potentiometer and the output voltage, and (b) is a graph showing the correlation between the output voltage and forward / reverse movement. [Figure 8] This is a flowchart of the snow removal unit's lifting and lowering control performed by the control unit. [Figure 9] This is a flowchart (continued) of the snow removal unit's lifting and lowering control performed by the control unit. [Figure 10] This is a flowchart (continued) of the snow removal unit's lifting and lowering control performed by the control unit. [Figure 11] This is a flowchart (continued) of the snow removal unit's lifting and lowering control performed by the control unit. [Modes for carrying out the invention]

[0026] Embodiments of the present invention will be described below with reference to the attached drawings. In the following explanation, up, down, front, back, left, and right are defined based on the operator holding the handle grips (Figure 1, reference numerals 45L and 45R). [Examples]

[0027] [Snowblower] As shown in Figure 1, the snowblower 10 consists of a traveling section 20 that travels on the road surface 11 and a snow removal section 30 mounted on the traveling section 20. The snow removal section 30 is tiltably supported on the traveling section 20 via a tilting support shaft 14. The road surface 11 can be any surface on which the snowplow 10 travels, including road surfaces, roadside surfaces, parking lot ground, and open field ground; the type of surface does not matter.

[0028] [Running section] The running section 20 consists of a running section frame 21 extending in the longitudinal direction (left and right in Figure 1), a drive shaft 22 rotatably mounted on the running section frame 21 and rotated by a drive source 32, a drive wheel 23 mounted on the drive shaft 22 and rotated by the drive shaft 22, a driven wheel 24 and an idler wheel 25 rotatably mounted on the running section frame 21, and a crawler 26 stretched across them. The crawler 26 has a large contact area and is therefore suitable for driving on snowy roads.

[0029] The drive wheels 23 and driven wheels 24 may be tires. If tires are used, the crawler 26 and idler wheels 25 are unnecessary. Balloon tires are preferred. Balloon tires are tires that are inflated like balloons with low-pressure air, and because they have a larger contact area than ordinary tires, they are suitable for driving on snowy roads. Alternatively, the drive wheels 23 may be tires and the driven wheels 24 may be skis. Therefore, the configuration of the running unit 20 is not limited to the embodiment.

[0030] [Snow Removal Department] The snow removal unit 30 consists of a snow removal unit frame 31 supported by the travel unit 20 via a drive shaft 22 which also serves as a tilting support shaft 14, an internal combustion engine 33 as a drive source 32 installed approximately in the center of the snow removal unit frame 31, a blower housing 35 provided at the front of the snow removal unit frame 31 to house a blower 34, a shoe 36 extending downward from the bottom of the blower housing 35, an auger housing 37 integrally formed at the front of the blower housing 35, an auger 38 housed in the auger housing 37 and extending in the front-back direction of the drawing, a chute 39 extending upward from the blower housing 35, a left handle 41L (L is a subscript indicating left; the same applies hereinafter) and a right handle 41R (R is a subscript indicating right; the same applies hereinafter) extending upward from the rear of the snow removal unit frame 31, an operating panel 50 provided between the left handle 41L and the right handle 41R, and a headlight 43 attached to the right handle 41R.

[0031] A lifting cylinder 44 is connected between the travel frame 21 and the snow removal frame 31. An electric hydraulic cylinder is preferred for the lifting cylinder 44. In Figure 1, the lifting cylinder 44 is extended. When the lifting cylinder 44 is retracted, the snow removal unit 30 tilts clockwise around the tilting pivot shaft 14, and the auger 38 approaches the road surface 11.

[0032] As shown in Figure 2, the lower limit position of the snow removal unit 30 is determined when the shoe 36 contacts the road surface 11. The power of the internal combustion engine 33 is used to rotate the drive wheels 23, the blower 34, and the auger 38.

[0033] On the left handlebar 41L, the driving clutch lever 46 is located above the left grip 45L, and the left steering lever 47L is located below the left grip 45L. The right steering lever 47R is located below the right grip 45R.

[0034] A drive clutch is provided in the power transmission system between the internal combustion engine 33 and the drive wheels 23. When the drive clutch lever 46 is squeezed, the drive clutch is engaged, and when it is released, the drive clutch is disengaged.

[0035] When the drive clutch lever 46 is squeezed, the drive wheels 23 are rotated, causing the snowblower 10 to move forward or backward. The auger 38 rotates, pushing the snow 12 accumulated on the road surface 11 towards the road. The blower 34, when rotated, sucks in the snow 12 that has been pushed aside and discharges it into the chute 39. Snow 12 is discarded via chute 39 in the desired direction and location.

[0036] In this embodiment, the main elements of the snow removal unit 30 are a blower 34, an auger 38, and a chute 39, but a dozer (snow pushing plate) that has a "V" shape or a "-" shape in plan view may also be used. Therefore, the snow removal unit 30 is not limited to this embodiment.

[0037] Furthermore, the drive source 32 may be an electric motor in addition to the internal combustion engine 33. Furthermore, while the internal combustion engine 33 is preferably a gasoline engine, it may also be a diesel engine.

[0038] Next, we will explain steering (left turn, straight ahead, right turn) based on Figure 3. Note that the left steering lever 47L is directly below the left grip 45L and not visible, and the right steering lever 47R is directly below the right grip 45R and not visible, but for convenience, they have been drawn to be visible.

[0039] The driving control lever 52, which functions as a driving control element 51 located in the center of the control panel 50, allows the driver to select forward, stop, or reverse. Details of the driving control lever 52 will be described later.

[0040] The chute rotation lever 53, located to the right of the drive gear lever 52, is a joystick. When the chute rotation lever 53 is tilted to the left, the chute 39 rotates to the left; when tilted to the right, the chute 39 rotates to the right; when tilted upwards, the chute 39 tilts so that the snow throwing distance is "closer"; and when tilted downwards, the chute 39 tilts so that the snow throwing distance is "farther". Other levers and buttons are explained in Figure 4.

[0041] When the left steering lever 47L is squeezed while the drive clutch lever 46 is engaged, the driving force to the left crawler 26L is cut off. As a result, the forward action of the right crawler 26R causes the snowblower 10 to turn to the left. When the drive clutch lever 46 is held and the right steering lever 47R is also held, the driving force to the right crawler 26 is cut off. As a result, the forward action of the left crawler 26L causes the snowblower 10 to turn to the right.

[0042] When the driving clutch lever 46 is held and both the left steering lever 47L and the right steering lever 47R are released, the snowblower 10 will move straight. When the driving clutch lever 46 is released (returned), the vehicle stops.

[0043] [Control Panel] As shown in Figure 4, the control panel 50 is equipped with a travel speed shift lever 52 and a chute rotation lever 53, as well as a snow removal unit adjustment lever 54, a snow removal clutch button 55, and an auto-lift switching button 56.

[0044] The snow removal unit adjustment lever 54 is a joystick that adjusts the posture of the snow removal unit 30 (more precisely, the auger 38). When tilted forward (up in the diagram) from the neutral position, the auger 38 descends; when tilted backward (down in the diagram), the auger 38 rises; when tilted to the left, the auger 38 tilts to the left; and when tilted to the right, the auger 38 tilts to the right.

[0045] The snow removal clutch button 55 is a push button that sets whether or not to perform snow removal. A snow removal clutch is provided in the drive system between the power source and the blower and auger. When this snow removal clutch is engaged, snow removal can be performed, and when the snow removal clutch is disengaged, snow removal cannot be performed.

[0046] The snow removal clutch button 55 rotates the auger, etc., when pressed and held, and stops the rotation of the auger, etc., when pressed again. It is prohibited for workers or people in the vicinity to approach the rotating auger. Therefore, even if the snow removal clutch button 55 is briefly pressed, such as by a worker's glove or sleeve touching it, the auger will not rotate. When stopping the auger's rotation, the snow removal clutch button 55 only needs to be briefly pressed, as it will switch to the safe side.

[0047] The auto-lift switch button 56 is an illuminated push button that switches between "auto-lift mode ON," which automatically raises the snow removal unit when reversing and automatically lowers it when moving forward, and "auto-lift mode OFF," which does not automatically raise or lower the snow removal unit. In other words, when the auto-lift switch button 56 is pressed, the "auto-lift mode is turned ON" and the button lights up.

[0048] Pressing the auto-lift switch button 56 again will turn "auto-lift mode OFF" and the button will turn off.

[0049] [Control Unit] The control panel 50 is equipped with a control unit 60. The control unit 60 performs the control flow described later. The control unit 60 may be built into the control panel 50 or it may be located in a separate location away from the control panel 50. In addition, the control unit 60 includes an upward timer 61 and a downward timer 62. The upward timer 61 may be an independent device or a timer circuit incorporated into the control circuit. The same applies to the downward timer 62.

[0050] The control unit 60 is equipped with a target ascent time setter 63 for setting the target ascent time, a target descent time setter 64 for setting the target descent time, and a correction coefficient setter 65 for setting the correction coefficient. The target ascent time setter 63 may be an independent device or it may be programmed. In this case, the setting value is changed by rewriting the program. The same applies to the target descent time setter 64 and the correction coefficient setter 65.

[0051] [Driving gear shift lever] Based on Figure 5, which is a view from arrow 5-5 in Figure 4, the drive gear shift lever 52 will be explained in detail. As shown in Figure 5, the travel gear shift lever 52 consists of a rectangular member 67, a stick 68 extending upward from this member 67, and a grip 69 fitted to the upper part of this stick 68. Member 67 is secured to brackets extending from the handles (Figure 1, reference numerals 41L and 41R) via support pins 71.

[0052] Furthermore, member 67 is provided with a pin 72 at a predetermined distance from the support pin 71. Furthermore, a rotary potentiometer 73 is provided on a member extending from the handle (Figure 1, reference numerals 41L and 41R), and a pin 72 is fitted into the fork portion 74 of this meter 73.

[0053] Additionally, a throttle wire (or throttle rod) 75 is connected to pin 72.

[0054] As shown in Figure 4, near the drive gear shift lever 52, there are markings "N" which means the neutral position (driving stopped), "F" which means the forward position, and "R" which means the reverse position. When the drive gear shift lever 52 is moved from "F" to "R" and when it is moved from "R" to "F", it always passes through "N".

[0055] The operation of the vehicle's gear shift lever 52, which has the above configuration, will be explained with reference to Figure 6. As shown in Figure 6(a), when the gear shift lever 52 is moved from "N" to "R", the pin 72 rotates counterclockwise around the support pin 71, and as a result, the fork section 74 rotates clockwise by an angle θr. At the same time, the throttle wire 75 is pulled, and the snowblower 10 moves in reverse. Depending on the amount the throttle wire 75 is pulled, the reverse speed changes from low reverse speed to high reverse speed.

[0056] As shown in Figure 6(b), when the gear shift lever 52 is moved from "N" to "F", the fork section 74 rotates counterclockwise by an angle θf. Simultaneously, the throttle wire 75 is returned (or pushed), causing the snowblower 10 to move forward. Depending on the amount the throttle wire 75 is returned (or pushed), the forward speed changes from low forward speed to high forward speed.

[0057] The operation of the rotary potentiometer 73 at this time will be explained based on Figure 7. A potentiometer is a sliding variable resistor, and its output voltage changes based on the rotation of the fork section. Figure 7(a) is a graph in which the rotation angle of the fork is plotted on the horizontal axis and the output voltage of the potentiometer is plotted on the vertical axis. The output voltage changes linearly in direct proportion to the change in rotation angle. That is, Vn is output at the neutral position N, Vn+1 (larger than Vn) is output at a rotation angle θf, and Vn-1 (smaller than Vn) is output at a rotation angle θr.

[0058] This output voltage is sent to the control unit (Figure 4, reference numeral 60). The control unit (Figure 4, reference numeral 60) recognizes forward, stop, or reverse movement according to the output voltage. In other words, as shown in Figure 7(b), it recognizes stopping at Vn, moving forward between Vn and Vn+1, and moving backward between Vn and Vn-1.

[0059] The driving control 51 shown in Figure 4 is preferably a driving speed change lever 52 that combines the functions of determining the direction of travel (forward, backward, and stop) and the function of increasing or decreasing the speed (i.e., changing the speed). However, the driving lever and the gear shift lever may be provided separately. In this case, the driving lever that determines the direction of travel (forward, backward, and stop) becomes the driving control 51.

[0060] The driving control 51 may be a dial-type control or a button-type control. For example, a dial-type control consists of an arc-shaped scale plate, a dial, and a rotary potentiometer. The scale plate is marked with "reverse," "stop," and "forward." Turning the dial from the stop scale to the forward scale causes the vehicle to move forward and the forward speed to increase, while turning it from the stop scale to the reverse scale causes the vehicle to move backward and the reverse speed to increase. Therefore, the travel control 51 is not limited to the travel gear shift lever 52.

[0061] The control unit according to the present invention (Figure 4, reference numeral 60) performs snow removal unit lifting and lowering control in addition to normal snow removal control. The control flow of this snow removal unit lifting and lowering control will be explained with reference to Figures 8 to 11. In control flow diagrams, the horizontally elongated hexagon is a selection chart symbol similar to the rhombus, and is used when the number of characters within the symbol is large.

[0062] [Operation of the control unit] In Figures 8 to 11, ST indicates the step number. In Figure 8, ST01 is used to determine the position of the snow removal adjustment lever (Figure 4, reference numeral 54). If the snow removal unit adjustment lever is not in the neutral position, it enters (manual lift mode), and the snow removal unit will move up / down / tilt left / tilt right based on the manually set position (ST02).

[0063] If the snow removal adjustment lever is in the neutral position, ST03 checks whether the auto-lift switch button (Figure 4, reference numeral 56) has been pressed and whether the machine is in auto-lift mode. In auto-lift mode, ST04 asks whether to set or change the target ascent time Tumax, the target descent time Tdmax, and the correction coefficient α. α is a value less than 1.0 and is determined by experimentally raising and lowering the snow removal unit.

[0064] If the answer is YES, ST05 sets or changes one or more of the target ascent time Tumax, target descent time Tdmax, and correction coefficient α. This setting or change is done using the setting devices (Figure 4, reference numerals 63-65) or by rewriting the program.

[0065] Next, ST06 checks the status of the snow removal clutch button (Figure 4, reference numeral 55). Press and hold the snow removal clutch button to turn it ON, and the auger will start to rotate. Pressing the snow removal clutch button again will turn it OFF, and the auger will stop rotating.

[0066] If the answer to ST06 is NO, the auger will remain stopped and no snow removal will be performed. Therefore, in ST07, the flags and timers will be cleared, and the process will return to the top of the flow. Also, if the answer is NO in ST01 and NO in ST03, proceed to ST07.

[0067] If the answer to ST06 is YES, then in ST08, the position information of the drive gear lever (Figure 4, reference numeral 52) is read. The position information is whether the drive gear lever has switched from the neutral position to the forward position, from the neutral position to the reverse position, is in the forward position, is in the neutral position, or is in the reverse position.

[0068] Figure 9 is a control flow diagram following Figure 8. In Figure 9, ST09 checks whether the gear shift lever has switched from the neutral position to the forward position. ST10 checks whether the gear shift lever has switched from the neutral position to the reverse position.

[0069] During the repeated control flow, the automatic ascent completion flag is set and cleared. Therefore, when it is determined that the vehicle is moving forward, ST11 checks for the presence of the automatic ascent completion flag. If the automatic ascent completion flag is present (set), ST12 clears the automatic ascent completion flag, ST13 sets the automatic descent flag, and ST14 clears the descent timer by setting the descent time Td to "0".

[0070] If the system determines in ST10 that the vehicle is in the neutral position, then in ST15 the automatic ascent flag is set, and in ST16 the ascent time Tu is set to "0" to clear the ascent timer.

[0071] Figure 10 is a control flow diagram following Figure 9. If you can confirm that the automatic lift flag is present (set) in ST17 of Figure 10, then in ST18, confirm that the drive gear shift lever is in the reverse position. Once confirmed, the ascent timer counts down (ST19) and the ascent time Tu is stored (ST20).

[0072] In ST21, we check whether the measured and accumulated ascent time Tu has reached the target ascent time Tumax. Since the ascent timer was cleared in ST16, the answer will be no for the time being. If not, the snow removal unit is driven upward (ST22), the automatic control flag is set (ST23), and the unit returns to the top position.

[0073] If the response in ST21 is YES, it is determined that the snow removal unit has finished rising, the automatic rising flag is cleared (ST24), and the automatic rising completion flag is set (ST25). When the answer to ST21 is YES, the measured ascent time Tu up to that point is essentially equal to the target ascent time Tumax.

[0074] Alternatively, if ST18 becomes NO (the position of the drive gear lever was changed to the neutral or forward position during the snow removal unit's ascent) before ST21 becomes YES, the automatic ascent flag is cleared (ST24) and the automatic ascent completion flag is set (ST25). When ST18 is NO, the measured ascent time Tu up to that point is shorter than the target ascent time Tumax.

[0075] Therefore, in ST26, instead of replacing (Tumax)×α with the target descent time Tdmax, we replace it with Tu×α. α is a value less than 1.0. This means that even if the ascent is interrupted midway, the target descent time Tdmax will be adjusted to match the height immediately before the interruption.

[0076] At ST27, the snow removal unit's elevation and descent are stopped, and at ST28, the automatic control flag is cleared, returning to the top position. When the automatic increase flag is cleared in ST24, it will be set to NO in the next ST17, and the process will proceed to Figure 11.

[0077] Figure 11 is a control flow diagram following Figure 10. If you can confirm that the automatic lowering flag is present (set) in ST29 in Figure 11, then in ST30 confirm that the drive gear shift lever is in the forward position. Once confirmed, the descent timer countdown begins (ST31), and the descent time Td is stored (ST32).

[0078] In ST33, we check whether the measured and accumulated descent time Td has reached the target descent time Tdmax. Since the descent timer was cleared in ST14, the answer will be no for the time being. If not, the snow removal unit is driven downward (ST34), the automatic control flag is set (ST35), and the unit returns to the top position.

[0079] When ST33 is set to YES, it is determined that the descent of the snow removal unit is complete, the automatic descent flag is cleared (ST36), the ascent and descent of the snow removal unit is stopped (ST37), the automatic control in progress flag is cleared (ST38), and the system returns to the top. If the answer at ST29 is NO, the snow removal unit will not descend, and the process will proceed to ST37 and ST38.

[0080] Of the effects described above, the most important ones are as follows: If the answer is YES at ST10 in Figure 9, the "automatic lifting flag" is set at ST15, then the answer becomes YES at ST17 in Figure 10, then YES at ST18, and the snow removal unit is driven to lift at ST22. Therefore, the control unit implements control to raise the snow removal unit when the travel control is switched from the neutral position to the reverse position.

[0081] Furthermore, if the answer is YES in ST21 (or NO in ST18) in Figure 10, the "automatic ascent flag" is cleared in ST24, and the "automatic ascent completion flag" is set in ST25. Next, if the answer is YES at ST09 in Figure 9, then it becomes YES at ST11, the "automatic descent flag" is set at ST13, then it becomes NO at ST17 in Figure 10, then YES at ST29 in Figure 11, then YES at ST30, and the snow removal unit is driven to descend at ST34. Therefore, the control unit implements control to lower the snow removal unit when the travel control is switched from the reverse position to the neutral position and then to the forward position.

[0082] In both the prior art and the present invention, the height of the automatically lowered working section (auger) may be finely adjusted at the operator's discretion. As the control flow described in Figures 8 to 11 is repeated, if the operator switches the snow removal unit adjustment lever (Figure 4, reference numeral 54) from neutral to any other position, such as raising (or lowering), then ST01 in Figure 8 becomes NO, the lifting unit is raised (or lowered) in ST02 to make fine adjustments to the height, and then the process returns to the top via ST07.

[0083] When the operator returns the snow removal unit adjustment lever to the neutral position, the control flow from ST03 onwards is executed. In other words, even if the operator makes fine adjustments to the height of the work unit, the auto-lift mode is maintained (without being canceled). There is no need to press the auto-lift switch button again.

[0084] In other words, according to the present invention, it is possible to interrupt the manual lift mode while maintaining the auto lift mode, and the lifting section can be raised, lowered, tilted to the left, and tilted to the right at any time, thereby improving the workability of the snowblower.

[0085] The present invention described above has the following advantages. Firstly, the automatic raising and lowering of the snow removal unit is controlled by an upward timer and a downward timer. Traditionally, tilt angle detection sensors and acceleration sensors have been used for this type of control. Tilt angle detection sensors and acceleration sensors have the advantage of being able to constantly monitor the height of the snow removal unit and accurately return the snow removal unit to the height at which it started to rise during descent. On the other hand, tilt angle detection sensors and acceleration sensors have the disadvantages of being expensive and being precision instruments that are prone to malfunction due to the impact force during snow removal.

[0086] In contrast, this invention employs both an upward timer and a downward timer. The timers can be included in the control circuit, resulting in virtually no cost increase. In addition, the timers are not affected by the impact force during snow removal.

[0087] Secondly, by multiplying by a correction factor α (a value less than 1.0), the target descent time was set to be shorter than the target ascent time. Due to gravity, the snow removal unit rises slowly and descends quickly. By setting the target descent time shorter than the target ascent time, the snow removal unit can be returned to the height it was at when it began to rise with almost perfect accuracy.

[0088] In addition, the target descent time was determined by using the measured value of the rise time, rather than the target rise time. This is because even if the upward movement of the snow removal unit is interrupted while it is rising, the target descent time will be adjusted to match the height it was at just before the interruption.

[0089] In other words, the second advantage is that the target descent time is replaced with a value obtained by the formula (ascending time counted by the ascending timer immediately beforehand) × (a value less than 1.0). Therefore, even if the ascending operation is interrupted while the snow removal unit is rising, the target descent time is adjusted to match the height immediately before the interruption, and the automatic mode is maintained.

[0090] In this embodiment, the tilting support shaft 14 is also used as the drive shaft 22, but it may be provided separately from the drive shaft 22. In short, it is sufficient that the snow removal unit 30 is tiltably supported on the traveling unit 20 via the tilting support shaft 14, and it is optional whether to use it as part of the drive shaft 22 or to provide it separately from the drive shaft 22.

[0091] Furthermore, in this embodiment, the snowblower 10 is a "walk-behind type snowblower" in which the operator walks on the road surface 11 while holding grips 45L and 45R. However, there is no problem in applying the present invention to a "ride-on type snowblower" operated by an operator riding on it, or to a "remote-controlled type snowblower" operated by an operator using a wireless or wired controller. [Industrial applicability]

[0092] This invention is suitable for snow removal machines that perform snow removal by repeatedly moving forward and backward. [Explanation of Symbols]

[0093] 10...Snowblower, 11...Road surface, 12...Snow, 20...Travel unit, 30...Snow removal unit, 32...Drive source, 51...Travel control unit, 60...Control unit, 61...Ascending timer, 62...Descending timer, Td...Descending time counted by the descending timer, Tu...Ascending time counted by the ascending timer, Tdmax...Target descending time, Tumax...Target ascending time, α...Correction coefficient.

Claims

[Claim 1] A running section that travels on the road surface using power from a drive source, A snow removal unit is tiltably mounted on this travel unit to remove snow accumulated on the road surface, A travel control element that switches between forward, neutral, and reverse positions to move the travel unit forward, stop, or reverse, The system includes a control unit that acquires switching information for the position of the travel control unit, and performs control to raise the snow removal unit when the travel control unit is switched from the neutral position to the reverse position, and to lower the snow removal unit when the travel control unit is switched from the reverse position to the forward position via the neutral position, A snowblower that reduces the burden on the operator by automatically raising the snow removal unit when reversing and automatically lowering the snow removal unit when moving forward during snow removal work, The control unit includes an upward timer for controlling the upward movement of the snow removal unit and a downward timer for controlling the downward movement of the snow removal unit. The upward movement of the snow removal unit is controlled by the upward timer and the downward timer, respectively, by completing the upward movement when the upward movement time counted by the upward timer reaches the target upward movement time, and completing the downward movement when the downward movement time counted by the downward timer reaches the target downward movement time. A snowblower characterized in that, if the travel control is switched to the neutral position or the forward position before the rising time counted by the rising timer reaches the target rising time, the target descending time is replaced with a value obtained by the formula (rising time counted by the rising timer immediately before) × (a value less than 1.0).

Images