Snow blower

Abstract

To solve the problem in which: in traditional small walking-type snow blowers, a shear bolt mechanism has been employed to safeguard an auger and its driving powertrain from failures or damage due to overload or impact, but operators frequently remain unaware when the shear bolt breaks; in the event of a breakage in the auger's shear bolt, prompt replacement and restoration are necessary; otherwise, the snow clogged by sticking or freezing becomes difficult to remove, rendering the shear bolt replacement extremely burdensome.SOLUTION: A substantially square hole is opened in a substantially central part between the right and left sides of an auger case, a plate-like non-magnetic cover is provided, and a magnetic proximity sensor is provided on the back side of the auger case opposite to an auger blade so as to face the auger blade, thereby detecting the rotating operation of the auger blade made of a steel plate.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a small rotary walk-behind snowplow used primarily by individuals, farms, stores, offices, small and medium-sized businesses, etc., and relates to improving the efficiency and comfort of snow removal operations. [Background technology]

[0002] Small walk-behind snowplows are now widely used for individual small-lot snow removal in snowy regions, separate from the large snowplows used on national and prefectural public roads and public facilities. Among them, rotary snowplows, which use a spiral rotating blade, or auger, to scrape and scrape the accumulated snow, collect it in a blower that ejects the snow, and release it from a semi-cylindrical chute that determines the ejection direction, have higher snow removal capacity than other types and are overwhelmingly more widely used. For a long time, this type of snowplow, whether small or large, has used a shear bolt mechanism to protect the auger and the powertrain that drives it from malfunctions and damage caused by overloads and impacts (Patent Document 1). That is, when the auger is rotating and it crashes into a wall of hard or packed snow, which could deform the auger blades or damage the power train, such as the transmission or drive shaft, or when the auger blades hit stones, rocks or road curbs on the road surface, which could damage the auger or power train, the shear bolts that secure the auger blades are sheared to protect them from failure or damage. Currently, there are many ideas for preventing auger overload, but most basically use the shear bolt configuration of Patent Document 1, which the applicant filed about 50 years ago. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Actual publication Showa 50-104430 [Patent Document 2] Patent Publication No. 10-298939 [Patent Document 3] Real new number 3132846 [Patent Document 4] Patent Publication No. 2020-143487 [Non-patent literature]

[0004] [Non-Patent Document 1] News Reiease Consumer Affairs Agency December 23, 2021 [Non-Patent Document 2] News ReieaseKanto Bureau of Economy, Trade and Industry December 22, 2022 Summary of the Invention [Problem to be solved by the invention]

[0005] However, during snow removal work, if the shear bolt breaks due to overload or impact, the operator often does not notice. If both the left and right bolts break, it is obvious, but if only one breaks, the other bolt can still continue to remove snow to a certain extent. Especially during snowfall in harsh winter conditions, or during busy snow removal work when every second counts, beginners often do not notice at all. If you continue snow removal without noticing, snow will accumulate on the broken auger and on the healthy auger blades as well, and snow will accumulate in clumps on the blower and chute due to reduced snow-cutting and discharge power. It is beginners who realize that the auger is running freely only after they see that snow has stopped being discharged from the chute. Experienced operators may notice the abnormality in the snow throwing situation when only one auger is clearing snow.

[0006] If the shear bolt of the auger breaks, it must be replaced and restored as soon as possible, otherwise snow will stick to it in clumps (sometimes it will freeze) and it will be difficult to remove the clogged snow. In addition, if the shear bolt cuts cleanly, it would be fine, but if it cuts incompletely and leaves burrs or chips (torn pieces), it will be difficult to even remove it from the bolt hole of the flange if it continues to run idle (rotate together), and repair work on the spot will be extremely difficult. And more than that, if the snow removal operation becomes abnormal, humans will inevitably try to look at the auger rotation from the front auger side, which can lead to serious accidents (fatal accidents such as being caught in the auger or being crushed under the machine, Non-Patent Documents 1, 2), creating a very dangerous situation. This is also something that cannot be seen when the machine is stopped, so it is left in operation. In recent models with a dead man device, when the operator takes his hands off the control, the power is cut off and the machine stops for safety, but on the other hand, this also triggers attempts to disable the dangerous dead man function. There have been several attempts to improve the protection mechanism using shear bolts (Patent Documents 2, 3, and 4), but none have been realized in products to date. Because it is the simplest mechanism, no mechanism that surpasses this shear bolt safety mechanism has yet been realized.

[0007] The present invention addresses the above-mentioned problems with rotary snowplows, that is, when a shear bolt breaks, the first priority is safety, and the operator is notified of the situation as soon as possible to prevent dangerous actions and to have the bolt replaced immediately, thereby minimizing troubles caused by broken shear bolts in the auger. If the bolt breaks immediately after it breaks, it can be easily replaced in the same way as a normal bolt replacement, even in the cold, without any trouble. Furthermore, work interruptions can be minimized. This further improves the safety of snow removal work, eliminates additional multiple troubles caused by broken shear bolts, improves work maintenance, and provides an excellent snowplow that is safe and dramatically improves snow removal work efficiency. [Means for solving the problem]

[0008] The means taken in this invention to solve the above-mentioned problems is a walk-behind rotary snow blower equipped with a prime mover and whose snow removal section is made up of an auger that cuts and collects snow, a blower that ejects snow, and a chute that determines the direction the snow is thrown. A roughly rectangular hole is opened approximately in the center of the left and right sides of the auger case that makes up the auger, and a roughly rectangular plate-shaped non-magnetic cover (non-magnetic cover) is provided that is roughly the same size as the opening. Magnetic proximity sensors are arranged opposite the auger blades on the opposite side of the non-magnetic cover to the auger blades, i.e., on the non-magnetic cover part on the back side of the auger case, so that they can detect the rotational movement of the left and right steel plate auger blades.

[0009] The shear bolt detection unit (computer unit) monitors the rotation of each of the left and right auger blades based on signals from the proximity sensors, and if rotation stops or becomes discontinuous, it determines that the shear bolt securing the auger blade to the auger shaft has broken, and immediately notifies the operator with a lamp display or an alarm display on the monitor panel, for each of the left and right sides. At the same time, a buzzer sounds and the operating levers, such as the snow removal section cross lever and HST lever, which are constantly operated, vibrate, appealing not only to the sight, but also to the hearing and physical senses, so that the operator is alerted as soon as possible. Effect of the Invention

[0010] By implementing the above-mentioned means, the present invention has the following effects.

[0011] If an accident occurs during snow removal work, such as an auger shear bolt breaking due to overload or impact load, the detection control system immediately notifies the operator multiple times, allowing the operator to notice the problem immediately and take quick action. This prevents the operator from taking dangerous actions by trying to watch the auger operation, improving safety and improving the workability of repairing the broken shear bolt.

[0012] Since immediate action can be taken when a shear bolt breaks, additional multiple problems caused by broken shear bolts, such as snow clogging the auger, blower, chute, etc. and difficulty in removing the bolt from the flange, are almost eliminated. Since the time required to restore from a breakdown is also minimized, the ease and efficiency of snow removal work is improved. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is an overall view showing a walk-behind rotary snow removal machine. [Diagram 2] FIG. 2 is a front view showing the auger unit of the walk-behind rotary snow remover. [Diagram 3] FIG. 13 is a diagram showing the mechanism for fastening the flange of the auger blade to the auger mission-auger shaft by a shear bolt. [Figure 4] FIG. 2 is a front view of the auger section showing the positions of the shear bolts and the position of the non-magnetic cover of the auger case made of a non-magnetic material, and a side view of the auger section showing the mounting position of the proximity sensor. [Diagram 5] 13 is a diagram showing a state in which a proximity sensor is fixed to the left side of the rear surface of the auger case. [Figure 6] 13 is a diagram showing a state in which a proximity sensor is fixed to the right side of the rear surface of the auger case. [Figure 7] FIG. 13 is a diagram showing an alarm issued when a bolt break is detected. [Figure 8] FIG. 11 is a control flowchart for detecting and warning a broken shear bolt. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] When trying to detect the rotation of the auger blades with a proximity sensor, only magnetic or ultrasonic types (can penetrate 20KHz or less) are available, which are not affected by snow adhesion on the auger blades and auger case. Furthermore, the gap between the auger blade tip and the auger case is designed to be 15mm (i.e. immediately after manufacture), and as snow is removed, the auger blade tip decreases, so even if it is close, a detectable gap of 20mm or more is required. Also, even if it is possible to detect the rotation of the auger blades, it is not the steel plate surface but the steel plate thickness surface (plate thickness about 4.5mm), so although it is possible, the reflection of ultrasonic burst waves becomes unstable and there are problems with performance stability. Even among magnetic types, electromagnetic pickup types (or magnet types) used for wheel rotation speed detection and work detection on high-speed lines have high responsiveness, but they are not applicable because their detectable gap is only a few mm, leaving the induction type. However, from the detection conditions of the detectable gap and the steel plate thickness surface, a low-frequency (1 to several hundred Hz) excitation type, which is different from the usual high-frequency (several KHz) excitation, is the optimal sensor type to satisfy these two conditions. EXAMPLES

[0015] An embodiment of the present invention will be described with reference to the attached drawings. FIG. 1 shows a perspective view (upper) of a snowplow of the embodiment as seen from the snowplow unit side, and a front view (lower) as seen from directly in front of the snowplow unit side. In a snowplow, the left and right auger blades LR (11-12) of the auger (1) usually scrape or scrape snow off, collect and collect it in the center, and then rotate at high speed with a blower (not shown) located at the back of the center of the auger blades LR (11-12), discharge the snow at the blower peripheral speed, and throw it at the location intended by the operator with the chute (3). When the snowplow is operated manually, the lift position and left and right rolling positions of the auger (1) are controlled with the snowplow unit cross lever switch (61) on the operation panel (6) (FIG. 7). Similarly, the chute cross lever switch (62) is used to control the left and right direction of the chute (3) and the distance at which the snow is thrown. The snowplow is moved by the crawler (51) or the traveling transmission (not shown). The HST lever (64) controls forward and reverse travel and its speed.

[0016] A front view focusing on the auger 1 is shown in Fig. 2, and its structural mechanism is shown in Fig. 3. The auger (1) has the hollow rotating shaft of the auger blades LR (11-12) inserted rotatably into the auger shafts LR (133-134), which are the left and right output shafts of the bevel gear type auger transmission (13), and is flange-fixed in a pair on the left and right and symmetrically on the left and right. For convenience of explanation, the left and right direction here refers to the view from the auger (1) side. Since the auger blades LR (11-12) only need to scrape off accumulated snow, they are made of mild steel plate and are treated as expendable parts without increasing their strength or hardness unnecessarily for reasons such as protecting the road surface and the powertrain. The auger blades LR (11-12) not only function as blades to scrape and break up accumulated snow, but also as a spiral conveyor that transports the snow to the center of the auger, to the blower (2) at the back of the auger mission (13), using the auger case (14) surface and the snow-cleaning surface as a guide (Fig. 2). The snow that has been scraped moves along the auger case 14 surface to the central auger mission (13), and is sent into the blower case (21) by the action of the auger rotation and the forward movement of the machine. Here, the auger blades are symmetrical, but are fixed so that there is a rotational phase difference of 90 degrees, so that vibration resonance caused by rotation is canceled (like the hand movement in swimming crawl), and snow is sent to the blower (2) alternately from the left and right without interruption. The blower (2) cuts and collects snow using the auger blades LR (11-12), and discharges the collected snow to the circumferential outlet of the blower case (21) using the centrifugal force of rotation and the compressed air force of the centrifugal compressor, and throws the snow using the semi-cylindrical chute (3) as a guide. The chute (3) can be adjusted left and right and up and down (near and far), so the snow throwing location can be freely set.

[0017] The left auger mechanism and shear bolt mechanism are shown in detail in Figure 3. The left auger blade L (11) is formed with a flange aL (111) on the auger mission 13 side, and after it is inserted into the left auger shaft L (133), it is fixed to the left flange bL (131) of the auger mission (13) with a shear bolt (112) and flange-coupled. If a torque greater than the shear stress is applied to this shear bolt (112) during snow removal work by rotating the auger blade L (11) in snow, it will break, causing the auger blade L (11) to spin freely, protecting the auger blades and power train from damage due to overload. The same is true for the right auger blade R (12). It is rare for both of these to break due to overload when removing snow, and usually only one of them breaks. As mentioned above, if you continue working without noticing, it can cause additional multiple problems. The size of the shear bolt (112) that determines this protective function is naturally selected according to the size of the snow blower. In order to explain the protective mechanism, Figure 3 shows the most basic cylindrical flange shape, but there are various flange shapes depending on the manufacturer, such as preventing the flange surface from freezing and sticking, and making it easier to replace the bolts. However, the protective mechanism against shear bolt breakage is basically as shown in Figure 3.

[0018] The mounting mechanism for the proximity sensor is shown in Figures 4, 5, and 6. Figures 4 and 5 show the mounting mechanism for the proximity sensor R (S2) that detects the rotation of the auger blade R (12), and Figure 6 shows the mounting mechanism for the proximity sensor L (S1) that detects the rotation of the auger blade L (11). In both cases, the proximity sensor LR (S1-S2) is fixed to the sensor bracket LR (145-146) fixed to the auger case (14) so ​​that it faces the steel plate thickness surface of the auger blade LR (145-146), just short of contacting the surface of the auger case (14). The bottom diagram in Figure 4 shows this state as seen from the side. The proximity sensor R (S2) is fixed to the sensor bracket R (146) on the surface of the auger case (14) facing the auger blade R (12). A slit-shaped hole was then drilled in this opposing part of the auger case (14) so ​​that the induced magnetic flux generated by the sensor could pass through, and a non-magnetic plate-shaped wall, non-magnetic cover R (142), which is a replacement for the steel plate of the auger case, was fixed there along the case surface. Because the non-magnetic cover needs to have the same strength as the steel plate, this time we used a polycarbonate plate with a thickness of 4 mm, which is relatively easy to process, but polymer or ultra-polymer polyethylene plates can also be used.

[0019] The top diagram in Figure 4 shows the left and right non-magnetic covers LR (141-142) as viewed from the front of the auger. After several prototype tests and the selection of the proximity sensor, the optimal shape was determined. When detecting the rotation of the auger blade R (12), the blade rotates from top to bottom toward the front in a spiral shape, so the steel plate thickness surface passes from right to left against the detection slit wall R (142). In addition, because the blade has two blades that are axially symmetrical, it passes twice per rotation. This is detected by the proximity sensor R (S2) on the back of the auger case (14). In the case of the auger blade L (11), the steel plate thickness surface passes from left to right against the non-magnetic cover (141), and this is detected by the proximity sensor L (S1).

[0020] With the above configuration, the gap between the outer steel plate thickness surface of the auger blade LR (11-12) and the proximity sensor LR (S1-S2) is expected to be about 25 mm in design. Proximity sensors that can detect gaps of 20 mm or more (no longer proximity) are limited in type, and especially magnetic types are very few. The proximity sensor we decided to use this time is a low-frequency induction type (eddy current detection type) with performance that is outside of common sense, with a maximum detectable gap of 40 mm, a stable detection gap of 30 mm, an oscillation frequency of 100 Hz, and a drive current of 0.2 A. Even though the detectable gap is about 30 mm, with an excitation frequency of 100 Hz, it can no longer be said to be for detecting moving objects but for detecting stationary objects. However, the rotation speed of the auger blade LR (11-12) is about 120 rpm at full throttle, which is 2 Hz, and the rotation speed from the two-row blade to the sensor is 4 Hz, which is almost sufficient because the purpose this time is not to detect the rotation speed accurately. The reason why the detection slit wall is larger than the original is because the 100Hz oscillation of the sensor is a radiating (diverging) magnetic flux, unlike other beam magnetic flux (several KHz oscillation, magnetic shield mechanism).Furthermore, the reason why the steel plate thickness surface could be detected is because the detection is hardly affected by the magnetic domain and magnetic wall direction of the steel plate, and it detects the surrounding area rather than the surface.

[0021] The main reason why rotation was possible with this unconventional configuration for proximity detection was that the auger blade LR (11-12) did not rotate as fast as it appeared when removing snow. Although the mechanism is similar to the wheel rotation detection of an automobile, the detection principle is completely different and can be said to be unique to rotary snowplows. With this configuration, there is a detectable gap of 5 to 10 mm, which allows for manufacturing variations and wear on the auger blade tips to be offset. In particular, with regard to wear on the auger blades, rotation detection performance can be maintained until the snow removal capabilities, such as scraping ability, snow cutting ability, and discharge ability, decrease and it is time to replace the blades with new ones (although this depends on the person).

[0022] Another problem with this proximity sensor is the large drive current of 0.2A. Although the detectable gap may be larger due to the significantly increased drive current in addition to the number of coil turns, there is still the problem of the sensor heating up. However, the sensor is used in a naturally cooled environment, where it is constantly on or in the snow, with the outside temperature below 5°C, and the continuous snow removal operation time is only a few minutes at most, as the auger blade rotation stops when changing direction or moving, and the detection circuit also stops during that time, so the sensor is not used continuously but intermittently, and therefore the cooling effect is greater.

[0023] With the above configuration, the proximity sensors LR (S1-S2) detect the rotation of the auger blades LR (11-12) during snow removal operation, and the shear bolt detection unit (U1) monitors whether the left and right blades are rotating normally and whether the left and right rotation phase difference is normal. If any abnormality occurs, such as a stop in rotation, discontinuous rotation (co-rotation), or an abnormal left and right rotation phase difference, it determines that the shear bolts LR (112-122) have broken and issues an alarm. Figure 7 shows the snow removal machine's control panel 6. The shear bolt detection unit (U1), which is a computer unit that inputs the output of the proximity sensors LR (S1-S2) that detect the rotation of the auger blades LR (11-12), is located on the back of this panel inside the machine body with an anti-vibration mechanism. When the shear bolt detection unit (U1) determines that the L shear bolt (112), or the R shear bolt (122), or both, have broken, it turns on the shear bolt warning display (631) on the monitor display section of the monitor & switch operation panel (63) to notify the operator.

[0024] The light is made to flash to improve visibility, so that the operator can easily notice it. In addition, a buzzer (65) sounds to appeal to the ear, and the operation lever, which is constantly being operated, is vibrated to appeal to the operator's senses, so that the operator can notice it as soon as possible. The lower right of Figure 7 shows the state in which a vibration motor for generating vibration is built into the snow removal section cross lever (61). Although there are slight differences depending on the person, from beginners to experts, during snow removal work, the left hand operates the HST lever (64) to control the moving speed, and the right hand uses the snow removal section cross lever switch (61) to adjust the auger (snow removal section) (1) up, down, left and right to control the snow removal load. The vibration motor is the same as that used in mobile phones and smartphones, and can be easily built into the vehicle. Some beginners remove snow while holding the operation handle (7), so a vibration motor is also installed on this. However, it is installed not on the handle (7) made of steel pipes, which has high rigidity, but on the sheet metal (dead man) handle lever (71) which is held together. (Diagram omitted)

[0025] A flow chart for shear bolt breakage detection control is shown in Figure 8. When the snowplow engine is started and the auger clutch switch (632) (Figure 7), an illuminated push button switch that operates the power clutch of the auger (1), is turned on to enter snow removal operation, the shear bolt detection unit (U1) begins detection operation and continues detection until the auger clutch switch (632) is pressed again, the auger clutch is disengaged and operation is interrupted. During this time, the shear bolt detection unit (U1) monitors the pulse signals sent from each of the proximity sensors LR (S1-S2), and immediately issues an alarm if it determines that a shear bolt has broken.

[0026] As described above, the present invention prevents dangerous actions by operators due to shear bolt breakage during snow removal work in harsh environments during snowfall in winter, when every second counts, and ensures safety. There are no longer any major interruptions to work, and snow removal can now be done without worry. Snow removal in winter is tough work, but this invention has contributed to improving safety from accidents, as well as workability and comfort in snowy winter environments. [Industrial Applicability]

[0027] This is a fairly rough method of detecting rotating objects (however slow) with a detectable gap of 20 mm or more, and it can be used in poor operating environments, so it can be used with slow-speed agricultural machinery (tractors, rice transplanters, etc.) and construction machinery. [Explanation of symbols]

[0028] 1 Auger (snow removal section) 11 Auger wing L (left side) 111 Flange aL (left auger blade side) 112 Shear bolt L (left side) 12 Auger wing R (right side) 121 Flange aR (right auger blade side) 122 Shear bolt R (right side) 13 Ogre Mission 131 Flange bL (left auger mission side) 132 Flange bR (right auger mission side) 133 Auger shaft L (left side) 134 Auger shaft R (right side) 14 Auger Case 141 Non-magnetic cover L (left side) 142 Non-magnetic cover R (right side) 143 Cover L (left side) 144 Cover R (right side) 145 Sensor bracket L (left side) 146 Sensor bracket R (right side) 2 Blower 21 Blower case 3 Shooter 4 Upper fuselage 5 Lower fuselage 51 Crawler 6 Control Panel 61 Snow removal unit cross lever switch 62 Shooter Cross Lever Switch 63 Monitor & Switch Operation Panel 631 Shear bolt warning display 632 Auger clutch switch 64 HST lever 65 Buzzer 7. Steering handle 71 (Deadman) Handle Lever S1 Proximity sensor L (left side) S2 Proximity sensor R (right side) U1 Shear bolt detection unit (computer unit)

Claims

1. This walk-behind rotary snowplow is equipped with a prime mover and has a snow removal section made up of an auger that cuts and collects snow, a blower that ejects snow, and a chute that determines the direction the snow is thrown. A roughly square hole is opened in the approximate center of each of the left and right sides of the auger case that makes up the auger, and a roughly square plate-shaped cover made of non-magnetic material is provided corresponding to the opening (non-magnetic cover). A magnetic proximity sensor is disposed opposite the auger blades on the side of the non-magnetic cover opposite the auger blades, i.e., on the non-magnetic cover part on the back side of the auger case, facing the auger blades, so that the snowplow is configured to detect the rotation of each of the left and right steel plate auger blades.

2. 2. The snow blower of claim 1, wherein a control unit (computer unit) monitors the rotational operation of each of the left and right auger blades based on signals from the proximity sensors, and if rotation stops or becomes discontinuous, it determines that the shear bolts securing the auger blades to the auger shaft have been broken for each of the left and right blades, and immediately notifies the operator with a buzzer or vibration of the operating lever, or with a warning display on a lamp or monitor for each of the left and right blades.

3. 3. The snow removal machine according to claim 1, wherein the magnetic proximity sensor is an induction type or an eddy current detection type magnetic proximity sensor.

4. 4. A snow blower according to claim 1, 2 or 3, wherein the non-magnetic material is ultra-high molecular weight polyethylene, high molecular weight polyethylene or polycarbonate.

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