1. Field of the Invention
The present invention relates to a snowplow vehicle having an engine equipped with a silencer or muffler for reducing the noise level when exhaust gases from the engine pass through the muffler.
2. Background Information
Rotary snowplow machines or vehicles equipped with a snowplow unit disposed at a front end of the vehicle body are known as disclosed, for example, in Japanese Utility Model Laid-open Publication (JP-UM-A) No. 64-5919. The snowplow unit of the disclosed snowplow vehicle comprises a snow worm or auger that delivers snow, a fan blower that throws the delivered snow upwardly, and a guide duct or shooter that guides the thrown snow into a selected direction. The snowplow vehicle has an engine mounted on an upper part of the vehicle body, left and right propelling crawler units disposed on lower left and right sides, respectively, of the vehicle body, and left and right handlebars extending from a rear part of the vehicle body in a backward direction of the vehicle. Thus, the disclosed snowplow vehicle is a self-propelled walk-behind vehicle that is maneuvered by a human operator walking behind the snowplow vehicle while grasping handgrips of the handlebars.
The self-propelled walk-behind snowplow vehicle includes an exhaust system having a muffler disposed on a left side of the engine above the left crawler belt, and a tail pipe extending from the muffler in a lateral outward direction of the snowplow vehicle. The muffler thus disposed is located at a relatively high position. To the operator who is standing near the muffler during snowplow operation, exhaust sound from the muffler is felt loud and unpleasant. Furthermore, the muffler located at a relatively high position may obstruct field of vision of the operator when the operator is looking ahead of the snow auger. A further problem is that when the snowplow vehicle is traveling alongside a snow wall, a stream of exhaust gases emitted from the tail pipe in a lateral outward direction is partly reflected from the snow wall in a backward direction of the snowplow vehicle and thereafter comes into the face of the operator. At the same time, the stream of exhaust gases may splash snow flakes from the snow wall, which will shower onto a body of the operator as the snowplow vehicle travels forward.
Another example of the conventional rotary snowplow vehicles is disclosed in Japanese Patent Publication (JP-B) No. 60-38491. The disclosed snowplow vehicle includes an engine mounted on a body of the vehicle, a top cover disposed on the vehicle body so as to conceal the engine with a space defined between a rear end of the vehicle body and a rear end the top cover, an exhaust pipe extending from the engine downward through the space between the vehicle body and the top cover, and a muffler connected to a lower end of the exhaust pipe.
The muffler thus arranged at a lower position of the snowplow vehicle does not obstruct forward view of the operator. However, since the muffler is disposed at the rear end of the vehicle body, exhaust sound from the muffler is still loud and gives unpleasant feel to the operator. Another drawback associated with the prior arrangement is that the space defined between the rear end of the vehicle body and the rear end of the top cover allows entry of radiant heat from the muffler, which will lower the engine cooling efficiency.
It is, accordingly, an object of the present invention to provide a self-propelled walk-behind snowplow vehicle having an exhaust system including a muffler arranged to ensure that exhaust sound from the muffler is sufficiently low and does not provide an unpleasant feel to the operator, obstruction-free forward view of the operator is maintained, the operator does not surfer from a blow of exhaust gases or a shower of snow flakes when the snowplow vehicle is traveling alongside a snow wall, and a high engine cooking efficiency can be retained.
According to the present invention, there is provided a self-propelled walk-behind snowplow vehicle comprising: a vehicle body; an engine mounted on an upper part of the vehicle body; left and right traveling units mounted on a lower part of the vehicle body at left and right sides thereof; and a muffler connected to the engine, the muffler being disposed below the engine and located between the left and right traveling units.
This arrangement allows the muffler to be disposed close to a ground surface so that the ground can take up or absorb exhaust sound emitted from the muffler. Additionally, since the position of the muffler is relatively far apart from the position of the head of an operator, the level of exhaust sound transmitted from the muffler to the operator is relatively low. The muffler disposed at such a low position does not obstruct forward view of the operator. Furthermore, particularly in winter seasons, radiant heat from the muffler is taken up or absorbed by the ground of low temperature or snow deposited on the ground surface. The muffler can be cooled with high efficiencies.
In one preferred form of the invention, the engine is a vertical engine having a crankshaft disposed vertically and a cylinder head disposed horizontally. The cylinder head projects from the vehicle body in a backward direction of the snowplow vehicle. The cylinder head of the engine, the vehicle body and the left and right traveling units together define a space open downward. The muffler is disposed in the space.
Preferably, the left traveling unit includes a left side frame extending in a longitudinal direction of the snowplow vehicle, a left driving wheel rotatably mounted on the left side frame, and the right traveling unit includes a right side frame extending parallel to the left side frame, and a right driving wheel rotatably mounted on the right side frame. The left and right side frames are connected together by a cross member, the cross member being disposed rearward of the muffler.
With this arrangement, the left side frame, right side frame and cross member together surround corresponding sides of the muffler and thus protect the muffler from damage. The left and right traveling units serve also as a protection member associated with the muffler. This eliminates the need for a separate protection member.
The self-propelled walk-behind snowplow vehicle may further comprise: a carburetor connected to the engine; a cover enclosing the engine, the cover having an air intake hole formed in a rear end portion thereof and open downward for introducing outside air into the cover and thence to the carburetor; the muffler being disposed below and forwardly of the air intake hole; and a partition wall disposed between the muffler and the air intake hole for blocking direct transmission of radiant heat from the muffler to the rear end portion of the cover including the air intake hole.
By thus blocking direct transmission of radiant heat from the muffler to the rear end portion of the cover including the air intake hole, the radiant heat gives no effect on the temperature of outside air to be introduced from the air intake hole into the cover. Thus, the engine can be cooled with high efficiency.
The partition wall may have an upper end vertically spaced from the cover and defining together with the cover a gap that allows limited transmission of radiant heat from the muffler to the rear end portion of the cover including the air intake hole. The thus transmitted radiant heat will thaw snow deposited around the air intake hole, thereby preventing snow from being drawn into the cover together with outside air, which would otherwise result in the occurrence of icing inside the cover.
Preferably, the cover has a bottom wall formed with an opening from which part of the air that has been used for cooling the engine is discharged, the muffler and the engine are connected together by an exhaust pipe extending vertically through the opening, and the partition wall is disposed rearward of the opening and configured so as to keep the discharged air from flowing behind the partition wall. The partition wall may have a generally U-shaped configuration and is disposed with an open side of the U-shaped configuration facing forward. With this arrangement, the air discharged from the opening can further cool the exhaust pipe.
In another preferred form of the invention, the self-propelled walk-behind snowplow vehicle further comprises an auger housing disposed forwardly of the vehicle body for receiving therein an auger driven by the engine, the auger housing extending in a widthwise direction of the snowplow vehicle. The muffler has a tail pipe so configured as to direct exhaust gases in a forward direction which is diagonal to a longitudinal centerline of the snowplow vehicle to the extent that a stream of exhaust gases discharged from the tail pipe does not strike on the auger housing.
Since the exhaust gases are discharged in a diagonally forward direction of the snowplow vehicle, exhaust sound can hardly be transmitted to the operator walking behind the snowplow vehicle. Additionally, since a stream of exhaust gases emitted from the tail pipe does not strike on the auger housing, it is possible to prevent freezing or icing from occurring inside the auger housing. When the snowplow vehicle is traveling alongside a snow wall, the stream of exhaust gases discharged from the tail pipe is reflected from the snow wall in a forward direction and does not give discomfort to the operator. Furthermore, snow flakes that may be created when the stream of exhaust gases strikes on the snow wall generally scatter in a forward direction of the snowplow vehicle and do not fly back toward the operator walking behind the snowplow vehicle.
A preferred structural embodiment of the present invention will be described in detail herein below, by way of example only, with the reference to the accompanying drawings, in which:
The following description is merely exemplary in nature and is in no way intended to limit the invention or its application or use.
Referring now to the drawings and
The propelling apparatus 14 includes a left traveling unit 26 disposed on a lateral outer side of the left motor 12, namely on a left side of the lower part of the transmission case 11, and a right traveling unit 27 disposed on a lateral outer side of the right motor 13, namely on a right side of the lower part of the transmission case 11. The left traveling unit 26 comprises a driving wheel 31 connected in driven relation to an output shaft of the left motor 12, an idler wheel 32 disposed rearward of the driving wheel 31 for free rotation, and a crawler belt 33 trained around the driving wheel 31 and the idler wheel 32.
The right traveling unit 27 has the same structure as the left traveling unit 26 just described above. Accordingly, structural parts of the right traveling unit 27 are designated by the same reference characters as those used in the left traveling unit 26, and further description thereof will be omitted.
The snowplow unit 16 comprises an auger section 35, a rotary blower section 36 and a shooter section 37. The rotary blower section 36 has a blower housing 61 mounted to a front end portion of the transmission case 11, and a blower 62 rotatably disposed in the blower housing 61. The blower 62 is mounted on a drive shaft 63 for rotation therewith. The auger section 35 has an auger housing 64 joined with a front end of the blower housing 61, and an auger 65 rotatably disposed in the auger housing 64.
The cover 18 is composed of an upper cover member 41 configured to cover or enclose the engine 15 from above, and a lower cover member 42 configured to cover a bottom surface of the engine 14. When assembled together to form the cover 18, the upper and lower cover members 41, 42 fully cover the engine 15. The engine 15 is a so-called “vertical” engine having a crankshaft 48 disposed vertically and a cylinder disposed horizontally.
In operation, the left and right motors 12, 13 are driven to rotate the left and right driving wheels 31 so that the left and right crawler belts 33 travel around the driving and idler wheels 31 and 32 to thereby propel the snowplow vehicle 10 in a desired direction. While the snowplow vehicle 10 is traveling forward, motive power from the engine 15 is transmitted to the auger 65 and the blower 62 for driving them to perform a snowplow operation.
As shown in
The engine 15 is provided with a carburetor 51 and an air cleaner 52 that are connected to a right side of the engine 15 (see also
The muffler 45 is disposed below and forward of the air intake hole 53. Stated more specifically, the muffler 45 is disposed substantially beneath a cylinder head 17 of the engine 15 (see also
As shown in
The muffler 45 has a tail pipe 67 extending from an end wall of the muffler 45 in a widthwise direction of the snowplow vehicle 10. The tail pipe 67 has a discharge end portion 68 bent forwardly at angle θ with respect to a line 114 parallel to a longitudinal centerline of the snowplow vehicle 10. The bent angle θ of the discharge end portion 68 is determined such that a stream of exhaust gases 71 (
If the stream of exhaust gases strikes on the auger housing 64, heat of exhaust gases will melt down snow inside the auger housing 64. The molten snow, i.e., water remaining inside the auger housing 64 may freeze up while operation of the snowplow vehicle 10 is stopped. Icing thus occurring inside the auger housing 64 will hinder or sometimes stop smooth start of the auger section 35. In case of the snowplow vehicle 10 of the invention, such icing problem does not occur because a stream of exhaust gases discharged from the forwardly bent discharge end portion 68 of the tail pipe 67 does not interfere with the auger housing 64. The phantom line 114 shown in
As shown in
The cross member 75 has a U-shaped cross section includes a vertical wall 76 and upper and lower horizontal walls 77 and 78 (
For assembly, the cross member 75 of forwardly open box-like configuration is fitted over the rear end portions 73b, 74b of the left and right side frames 73, 74, and left and right end portions 75a, 75b of the cross member 75 and the rear end portions 73b, 74b of the left and right side frames 73, 74 are connected together by a plurality of screws 83.
The cross member 75 has a bracket 85 at a central portion thereof. The bracket 85 is connected to a lower end 86a of a cylinder actuator 86 (
As previously discussed, the muffler 45 is disposed between the left and right side frames 73, 74 (i.e., between the left and right traveling units 26, 27) with the cross member 75 disposed behind the muffler 45. With this arrangement, left and right end walls 45a, 45b of the muffler 45 are protected by the left and right traveling units 26, 27, respectively, and a rear part 45c of the muffler 45 is protected by the cross member 75. The muffler 45 thus protected is substantially free from damage. By thus using the traveling units 26, 27 as a protection means, the muffler 45 does not require a separate protection member.
The muffler 45 is in the form of an elliptical cylinder disposed horizontally with its axis extending transversely of the transmission case 11 (
As shown in
The partition wall 55 is disposed upwardly and rearward of the muffler 45. As shown in
The left and right support brackets 101, 102 have mounting flanges 101a, 102a (
Operation of the snowplow vehicle 10 of the foregoing construction will be described with reference to
The remaining part of the air is forced against the engine 15 to cool the engine 15, as indicated by the arrow E. After cooling the engine 15, the air is discharged from the opening 44 of the lower cover member 42 into a space extending forwardly of the partition wall 55, as indicated by the arrow F. In this instance, the partition wall 55 guides the air in a downward direction, as indicated by the arrow G, so that the air flows downward along the exhaust pipe 46, thereby cooling the exhaust pipe 46.
By virtue of the partition wall 55 disposed vertically between the air intake hole 53 and the muffler 45, the air discharged from the cover 16 is guided downward toward the muffler 45, as indicated by the arrow G, and is prevented from being introduced again from the air intake hole 53 into the cover 18. By thus blocking reentry of the air into the cover 18, the engine 15 received inside the cover 18 can be cooled with high efficiencies. The partition wall 55 disposed between the muffler 45 and the air intake hole 53 is effective to separate the air intake hole 53 from the muffler 45 to thereby block unlimited direct transmission of radiant heat from the muffler 45 to the air intake hole 53.
When outside air is introduced from the air intake hole 53 into the cover 18 with snow flakes or powders entrained in the air, the snow powders may cause freezing or icing inside the cover 18. To avoid this problem, the vertical space or gap 58 is provided between an upper end of the partition wall 55 and the bottom wall 43 of the cover 18 so that a necessary amount of radiant heat is allowed to transmit from the muffler 45 to the air intake hole 53. The term “necessary amount of radiant heat” means an amount of radiant heat which is sufficient to melt down and vaporize snow 106 adhering to a neighboring part of the air intake hole 53 but does not affect cooling of the engine 15 when introduced from the air intake hole 53 into the cover 18. By thus introducing the necessary amount of radiant heat from the muffler 45 into the air intake hole 53, the snow 106 adhering to the neighboring part of the air intake hole 53 will melt down and become vapor. Furthermore, since the partition wall 55 is heated by radiant heat from the muffler 45, deposited snow 106 on the partition wall 45 can be also melting down and vaporized. This ensures that the air introduced from the air intake hole 53 into the cover 18 is free from snow flakes or powders entrained therein and the freezing or icing problem does not occur inside the cover 18.
As previously described, the muffler 45 is disposed below the engine 15 and located between the left and right traveling units 26, 27. Stated more specifically, the engine 15 (more particularly the cylinder head 17 of the engine 15) and the left and right traveling units 26, 27 define the space 109 open downward, and the muffler 45 is disposed in the space 109. This arrangement allows the muffler 45 to be located near the ground surface 108. The muffler 45 thus arranged is kept sufficiently far from the head of the operator walking behind the snowplow vehicle 10 and does not obstruct forward field of vision of the operator when looking ahead of the auger section 35 (
In the illustrated embodiment, the partition wall 55 has a U-shaped configuration, as shown in
As shown in
As shown in
As thus far explained, the invention is practiced or embodied in a self-propelled walk-behind snowplow vehicle 10 of the type having a snowplow unit 16 including an auger section 35 and a blower section 36. This invention may be practiced or embodied a snowplow vehicle having a different type of snowplow unit. Furthermore, while in the illustrated embodiment, the partition wall 55 is disposed vertically, a backwardly tilted partition wall may alternatively used. Additionally, the partition wall 55 of U-shaped configuration may be replaced with a partition wall having a generally C-shaped configuration. In the illustrated embodiment, the partition wall 55 and the bottom wall 43 of the lower cover member 42 are vertically separated by the space 58. In a modified embodiment, the partition wall 55 may be held in contact with the bottom wall 43 of the lower cover member 42. Furthermore, the partition wall 55 in the illustrated embodiment is bolted to the left and right handlebars 21, 22. The way of attachment of the partition wall 55 should by no means be limited to one shown in the illustrated embodiment but may include another way of attachment wherein the partition wall 55 is attached to the lower cover member 42.
Furthermore, the shape and configuration of the muffler 45 is not limited to an elliptical cylinder as in the illustrated embodiment but may be selected at option. Similarly, the tail pipe 45 has no limitation in shape and configuration thereof except for a particular orientation of the discharge end portion 68. Additionally, the shape and configuration of the cross member 75 is not limited to one shown in
Obviously, various minor changes and modifications of the present invention are possible in the light of the above teaching. It is therefore to be understood that within the scope of the appended claims the present invention may be practiced otherwise than as specifically described.
Number | Date | Country | Kind |
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2003-297852 | Aug 2003 | JP | national |
2003-297874 | Aug 2003 | JP | national |
2003-297920 | Aug 2003 | JP | national |
Number | Name | Date | Kind |
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4821691 | Ueno et al. | Apr 1989 | A |
5438770 | Miller | Aug 1995 | A |
6226966 | Eavenson et al. | May 2001 | B1 |
6318003 | Heismann | Nov 2001 | B1 |
6327799 | Hanafusa et al. | Dec 2001 | B1 |
6427364 | Heismann et al. | Aug 2002 | B1 |
6643959 | Jolliff et al. | Nov 2003 | B1 |
Number | Date | Country |
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60038491 | Feb 1982 | JP |
64005919 | Jan 1989 | JP |
2005-68732 | Mar 2005 | JP |
Number | Date | Country | |
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20050039354 A1 | Feb 2005 | US |