SNOW BLOWERS

Description

FIELD

The improvements generally relate to snow blowers, and more specifically relate to construction changes which can provide snow removal efficiency gains.

BACKGROUND

Snow blowers have been used for decades and constitute a highly popular, mechanized way of moving snow. In particular, one significant feature of a snow blower is its efficiency, which can be associated to the rate at which snow is handled/displaced. More specifically, for a machine of a given size and power rating, a more efficient machine will handle a greater amount of snow (by volume, by weight or both) per unit of time than a less efficient machine, in similar snow conditions. This metric is particularly important because snow blowers are typically highly solicited during snowstorms and to deal with their aftermath, and these events can be relatively focused in time and represent a certain degree of urgency. The efficiency metric can also be relevant for industrial grade snow blowers as they will affect the productivity of a given machine. A given snow blower operator may wish to deal with the snow in an efficient manner to deal with different clients more quickly, for instance, and lead to less waiting time and overall greater client satisfaction. Another significant feature of a snow blower is its ability to deal with the material it is being fed. While a typical use case involves feeding the snow blower with a good layer of fresh snow, which may have been packed to a certain extent or not, several other use cases exist and may need to be addressed. In particular, snow is a very particular material which can evolve over time depending on factors such as atmospheric conditions. Indeed, over a given time period, more than one snow storm may occur, rainfall may also occur, and temperature fluctuations both above and below freezing may occur. Such factors, taking into consideration that snow further naturally packs over time, lead to scenarios where the snow can be a heterogeneous mix of powdery layers, ice layers, and even in some cases include debris such as gravel (all possible mixes thereof being generally referred to as “snow” herein for simplicity). One of the most significant aspects of efficiency is avoiding breakage in various use conditions, since the efficiency of a broken snow blower is nil until it is repaired, which can take time and can be particularly undesired in the critical moments surrounding a snow storm, when the need for clearing snow quickly may be particularly strong. While existing snow blowers were satisfactory to a certain degree, there always remains room for improvement.

SUMMARY

In accordance with one aspect, it was found that while most of the snow reaching the impeller was thrown out of the chute, a certain amount of the snow could recoil back out of the snow blower, over a tip fence, where it needed to be handled again. Overall, this represented a loss of efficiency because the work of a certain percentage of the snow had to be repeated twice or more. Although the tip fence axially encloses the tips of the impeller blades, it was found that when the front edges of the impeller blades protrude too much from the tip fence, then they can create a wall preventing snow thrown by the auger to actually reach the impeller. There was thus a need in improving the construction of the impeller blades relative to the tip fence. For instance, the radial dimension of the front edges of the blades can be reduced so that the front edges do not radially inwardly clear the tip fence by more than half of the radial dimension of the front edges of the blades.

In accordance with another aspect, it was found that by reducing the radial dimension of the front edges of the impeller blades, the structural integrity of the blades could be adversely affected. Accordingly, it was found that by providing the blades with a suitably sloping oblique edge extending axially inwardly and rearwardly towards the hub, blades of satisfactory integrity could still be achieved.

In accordance with another aspect, it was found that by sloping the front edges of the blades circumferentially in the direction of rotation of the impeller so as to reach at least 85° relative to the corresponding tips, then a greater amount of snow could be captured by the blades, which in turn can increase snow removal efficiency.

In accordance with a first aspect of the present disclosure, there is provided a snow blower comprising: a primary housing having a back wall extending laterally and upwardly and two side walls extending forwardly from opposite lateral ends of the back wall, the back wall having a central opening; an auger mounted between the side walls, in the primary housing, and rotatable around an auger axis extending between the side walls, to move snow in the primary housing away from the side walls; a secondary housing recessed from the back wall and open to the primary housing via the central opening, the secondary housing having a cylindrical wall having a tangential opening; an impeller rotatably mounted in the secondary housing around an impeller axis coinciding with an axis of the cylindrical wall, the impeller axis forwardly oriented, the impeller having a plurality of impeller blades circumferentially interspaced from one another, the blades having a tip adjacent to the cylindrical wall and an axially forward front edge having a first radial dimension; a chute extending tangentially relative the impeller axis, from the tangential opening of the secondary housing; and a tip fence being annular in shape, the tip fence protruding radially from the cylindrical wall adjacent the front edge of the blades and spanning at least a portion of the circumference of the cylindrical wall, the front edges of the blades radially clearing the tip fence by at most half of the first radial dimension.

Further in accordance with the first aspect of the present disclosure, the front edges of the blades can for example radially clear the tip fence by a third of the first radial dimension.

Still further in accordance with the first aspect of the present disclosure, the front edges of the blades can for example radially clear the tip fence by at least a quarter of the first radial dimension.

Still further in accordance with the first aspect of the present disclosure, the cylindrical wall can for example have a given diameter, the tip fence can for example have a second radial dimension corresponding to the given diameter divided by a given number, the number can for example vary between 12 and 20, preferably varying between 13 and 18, and being most preferably 15.

Still further in accordance with the first aspect of the present disclosure, when the given diameter can for example be about 30 inches, the second radial dimension is about 2 inches.

Still further in accordance with the first aspect of the present disclosure, the first radial dimension can for example range between about 2.625 inches and 2.25 inches.

Still further in accordance with the first aspect of the present disclosure, the blades can for example have an oblique edge extending radially inwardly from the front edge and extending rearwardly, the oblique edge forming an angle greater than 25° relative to the impeller axis.

Still further in accordance with the first aspect of the present disclosure, the front edges can for example slope in a direction of rotation of the impeller, the front edges forming an angle of at least 85° relative to the corresponding tips.

In accordance with a second aspect of the present disclosure, there is provided a snow blower comprising: a primary housing having a back wall extending laterally and upwardly and two side walls extending forwardly from opposite lateral ends of the back wall, the back wall having a central opening; an auger mounted between the side walls, in the primary housing, and rotatable around an auger axis extending between the side walls, to move snow in the primary housing away from the side walls; a secondary housing recessed from the back wall and open to the primary housing via the central opening, the secondary housing having a cylindrical wall having a tangential opening; an impeller rotatably mounted in the secondary housing around an impeller axis coinciding with an axis of the cylindrical wall, the impeller axis forwardly oriented, the impeller having a plurality of impeller blades circumferentially interspaced from one another, the blades having a tip adjacent the cylindrical wall, an axially forward front edge, and an oblique edge extending radially inwardly from the front edge and extending rearwardly, the oblique edge forming an angle greater than 25°relative to the impeller axis; and a chute extending tangentially relative the impeller axis, from the tangential opening of the secondary housing.

Further in accordance with the second aspect of the present disclosure, the angle can for example range between 25° and 40°, and is preferably 35°.

Still further in accordance with the second aspect of the present disclosure, the oblique edge can for example extend radially inwardly for at least 75% of a radial dimension of the blades.

Still further in accordance with the second aspect of the present disclosure, the snow blower can for example further comprise a tip fence being annular in shape, the tip fence can for example protrude radially from the cylindrical wall adjacent the front edge of the blades and spanning at least a portion of the circumference of the cylindrical wall, the front edges can for example have a first radial dimension and radially clearing the tip fence by at most half of the first radial dimension.

Still further in accordance with the second aspect of the present disclosure, the axially forward front edges can for example slope in a direction of rotation of the impeller, the front edges forming an angle of at least 85°relative to the corresponding tips.

Still further in accordance with the second aspect of the present disclosure, the oblique edge can for example have a convex shape.

In accordance with a third aspect of the present disclosure, there is provided a snow blower comprising: a primary housing having a back wall extending laterally and upwardly and two side walls extending forwardly from opposite lateral ends of the back wall, the back wall having a central opening; an auger mounted between the side walls, in the primary housing, and rotatable around an auger axis extending between the side walls, to move snow in the primary housing away from the side walls; a secondary housing recessed from the back wall and open to the primary housing via the central opening, the secondary housing having a cylindrical wall having a tangential opening; an impeller rotatably mounted in the secondary housing around an impeller axis coinciding with an axis of the cylindrical wall, the impeller axis forwardly oriented, the impeller having a plurality of impeller blades circumferentially interspaced from one another, the blades having a tip adjacent the cylindrical wall and an axially forward front edge sloping in a direction of rotation of the impeller, the front edges forming an angle of at least 85° relative to the corresponding tips; and a chute extending tangentially relative the impeller axis, from the tangential opening of the secondary housing.

Further in accordance with the third aspect of the present disclosure, the angle can for example be of about 90°.

Still further in accordance with the third aspect of the present disclosure, the front edges can for example extend circumferentially defining a first edge portion located at a radially outward position and facing the cylindrical wall, the first edge portion can for example form an angle of at least 85° relative to a radially inward direction.

Still further in accordance with the third aspect of the present disclosure, the front edges can for example extend circumferentially defining a second edge portion located at a radially inward position and facing the impeller axis, the second edge portion can for example form an acute angle relative to a radially inward direction.

Still further in accordance with the third aspect of the present disclosure, the acute angle can for example be of at most 85°.

Still further in accordance with the third aspect of the present disclosure, the snow blower can for example further comprise a tip fence being annular in shape, the tip fence can for example protrude radially from the cylindrical wall adjacent the front edge of the blades and spanning at least a portion of the circumference of the cylindrical wall, the front edges can for example have a first radial dimension and radially clearing the tip fence by at most half of the first radial dimension.

Still further in accordance with the third aspect of the present disclosure, the blades can for example have an oblique edge extending radially inwardly from the front edge and extending rearwardly, the oblique edge can for example form an angle greater than 25° relative to the impeller axis.

Still further in accordance with any of the aspects of the present disclosure, the blades can for example extend, from corresponding circumferential positions spaced apart from one another, inwardly away from the impeller axis, the blades forming an angle relative to the radial orientation.

All technical implementation details and advantages described with respect to a particular aspect of the present invention are self-evidently mutatis mutandis applicable for all other aspects of the present invention.

Many further features and combinations thereof concerning the present improvements will appear to those skilled in the art following a reading of the instant disclosure.

DESCRIPTION OF THE FIGURES

In the figures,

FIG. 1 is an oblique view of an example of a snow blower during operation, in accordance with one or more embodiments;

FIG. 2 is a front elevation view of the snow blower of FIG. 1 between periods of operation, in accordance with one or more embodiments;

FIG. 3 is an oblique view of the snow blower of FIG. 1, focusing on the secondary housing and impeller, in accordance with one or more embodiments;

FIG. 4 is another oblique view of the snow blower of FIG. 1, showing a front edge of the impeller and the tip fence, in accordance with one or more embodiments;

FIG. 5 is a schematic cross-sectional view representing the relationship between the impeller and the chute, in accordance with one or more embodiments;

FIG. 6 is a partial cross-section view taken across the impeller, along with a blade of the impeller, in accordance with one or more embodiments;

FIG. 7 is a cross-section taken along lines 7-7 of FIG. 6, in accordance with one or more embodiments;

FIG. 8 is a front elevation view of another example of a snow blower, showing an impeller having three blades, in accordance with one or more embodiments;

FIG. 9 is an oblique view of the impeller of FIG. 8, in accordance with one or more embodiments;

FIG. 10 is a top view of another example of a snow blower impeller, showing non-radially extending blades, in accordance with one or more embodiments;

FIG. 11 is a side view of the snow blower impeller of FIG. 10, in accordance with one or more embodiments;

FIG. 12 is an oblique view of an exemplary an auger of a snow blower, showing an example of a toothed flight, in accordance with one or more embodiments;

FIG. 13 is a sectional view of another example of a toothed flight, in accordance with one or more embodiments; and

FIG. 14 is a sectional view of yet another example of a toothed flight, in accordance with one or more embodiments.

DETAILED DESCRIPTION

FIG. 1 shows an example of a snow blower 10 in accordance with one embodiment. The snow blower is shown during operation, handling snow. The snow blower can be seen to generally have a primary housing 12 where the snow is fed/collected, and a chute 14 via which the snow is ejected. Chutes are typically articulated and their operation can allow to control the orientation of the snow being ejected by the operator.

To facilitate comprehension and simplify the text, a few spatial references will be defined. In this specification, the expression “longitudinal” will refer to the orientation of movement of the snow blower 10 as a whole during operation. The snow blower 10 moves into the snow, and it is this longitudinal movement of the snow blower 10 which feeds snow into the primary housing 12. The expression “front” will refer to this direction of movement of the snow blower 10 towards the snow, independently of the fact that the snow blower 10 may be in fact attached to a rear of a tractor 16. Accordingly, in the illustrated example, moving the tractor 16 rearwardly moves the snow blower forwardly. The expression “lateral” will refer to an orientation which, like “forward” or “rearward,” extends horizontally relative to the ground, but which extends transversally to the “longitudinal” orientation of motion, to the sides of the snow blower 10. Accordingly, the frontal opening of the primary housing 12 spans a certain laterally oriented dimension extending between side walls 22a and 22b, and a certain height. A top wall can close the primary housing 12 at the top.

FIG. 2 presents an inside configuration of the primary housing 12 of the snow blower 10 of FIG. 1 subsequently to operation, empty of snow. The snow blower 10 can be seen to have a secondary housing 18 forming an intermediary between the primary housing 12 and the chute 14. In this embodiment, the secondary housing 18 is embodied as a cylindrically shaped recess formed in the back wall 20 of the primary housing 12. The main principle of operation of the snow blower 10 can involve a two-step process. In a first step, the snow fed into the primary housing 12 is somewhat trapped inside the primary housing 12 by a back wall 20 and side walls 22a and 22b in the context of the front motion of the snow blower 10 as a whole. The snow collected in the primary housing 12 is conveyed laterally towards the location of the secondary housing 18 by a helical component which will be referred to herein as an auger 24. Typically, the auger 20 has two sections 26a and 26b, one extending on each lateral side of the primary housing 12, relative to the secondary housing 18 which can be provided centrally. The snow thus accumulates in the center where it becomes forced into the circular opening of the secondary housing 18. An impeller 28 is provided in the secondary housing 18 which throws the snow accumulating therein into the chute 14.

The auger sections 26a and 26b have helical pushing segments 30 commonly referred to as “flights” which, when rotated around an auger axis A which extends laterally, tend to push the snow towards the center of the primary housing 12. To this end, the circumferential orientation of the helical pushing segments 30 around the auger axis A is opposite between the left-hand side auger section 26a and the right-hand side auger section 26b, and the angular direction of rotation of the auger around the auger axis A is selected in a manner for the pushing segments 30 to push laterally towards the center, not away from the center. In this embodiment, both auger sections 26a and 26b have flights 30 incorporated as a single component with a central shaft 32 extending entirely across the primary housing 12, from one side wall 22a to the other side wall 22b. In this specific example, the flights 30 are secured to the central shaft 32 with brackets. The flights 30 can be provided with different types of teeth and/or oars, as will be described below. Different variations for any of these are possible in some alternate embodiments.

The impeller 28 can have a plurality of blades 34 which rotate around an impeller axis B coinciding with an axis of the cylindrical wall 38. The impeller axis B extends longitudinally. As shown in this specific example, the blades 34 extend generally radially from a hub 36 which coincides with the impeller axis B. As the snow in the secondary housing 18 becomes engaged by the blades 34, the blades 34 impart a tangential acceleration to the snow, and the snow becomes also pushed radially outwardly due to the centripetal effect. The snow can, to a certain extent, pack against the circumferential wall 38 as it continues to be pushed by the blades 34 of the impeller 28 until it reaches the opening of the chute 14, where tangential velocity of the snow is allowed to proceed unhindered by the circumferential wall 38, into and through the chute 14.

In many embodiments, the rotation of the auger 24 and impeller 28 will be driven by one or more engine (not depicted) which may be a heat engine. Their rotation needs to overcome friction in addition to performing useful work moving the snow, consuming a certain amount of power. These components may need to be relatively robust to avoid breakage in different scenarios of operation, including scenarios of operation which may involve the introduction of foreign objects such as rocks into the snow blower 10 together with the snow. This being said, while robustness may often be achieved by thicker components, this leads to additional costs and additional weight, and excess weight is not necessarily desirable as it is often associated with greater frictional resistance. Appropriate grades and thicknesses of metals such as steel may be preferred for several of the parts of the snow blower 10 to achieve a balance between ruggedness and weight, combined with careful structural design. Moreover, the design of the snow blower 10 can involve considering the somewhat rheological flow of various potential conditions of snow, including snow which can involve fragments of ice and even rocks of varying sizes. To promote efficiency, a path of snow can be provided for, extending laterally inwardly in the primary housing 12, rearwardly into the secondary housing 18, circumferentially (relative to the impeller axis B) in the secondary housing 18, and tangentially out of the chute 14, in a somewhat fluidic manner. The flow of snow in the snow blower 10, however, is more complex than a simple fluid such as a liquid, especially taking into consideration the different conditions in which the snow may be in various scenarios of use.

In the illustrated embodiment, various efficiency enhancing elements can be associated to achieving a suitable level of efficiency and operability. Some of these elements will now be explained. FIG. 3 presents an oblique view of the impeller 28 showing how the impeller blades 34 generally extend radially relative to the hub 36 and rotate around the impeller axis B. As depicted, the blades 34 have tips 40 forming radial ends and which are configured to almost touch the cylindrical wall 38 of the secondary housing 18. The snow blower 10 can be provided with an annular tip fence 48. The tip fence 48 can be generally annular in shape, though shown as continuous can be discontinuous in some other embodiments, and can protrude radially inwardly from the cylindrical wall 38 of the secondary housing 18, as close as reasonable/feasible to front edges 41 of the impeller blades 34. Indeed, it was found that while it can be desired for the impeller 28 to be as unobstructed as possible to allow the forward to rearward motion of the snow between the primary housing 12 and the secondary housing 18, the greatest concentration of forwardly directed force on the snow in the secondary housing 18 occurred at the radial ends of the impeller blades 34. In the depicted embodiment, the tip fence 48 has a full radial span at it extends along a full circumference of the secondary housing 18. It was found that such tip fence 48 can advantageously prevent the egress of snow in the forward direction. In some other embodiments, providing a tip fence having only a limited radial span can also prevent the egress of snow in the forward direction along that span and have a significant effect on efficiency.

As depicted, the axially forward front edges 41 of the blades 34 have a first radial dimension r1. The front edges 41 are sized such that the front edges 41 clear the tip fence 48 along a radially inward direction by at most half (i.e., 50%) of the first radial dimension r1. It was found that upon forcing of the snow rearwardly towards the secondary housing by the auger 24, any exposed surface of the blades 34 can prevent the snow from actually reaching, or stay within, the secondary housing 18, and can then fall towards the primary housing and eventually back out of the snow blower, representing a penalty on efficiency. As such, by providing blades 34 having an axially forward front edges 41 that only extend a little in the inwardly radial direction passed the tip fence 48, a greater amount of snow forced into the secondary housing by the auger 24 can actually have a chance of being caught by the blades 34 for expulsion via the chute, rather than blocked by an elongated forward facing radial wall at each blade.

Still referring to FIG. 3, the tips 40 can be broader than the radially inner portion of the blades 34, to provide an unobstructed volume in the center of the secondary housing 18 into which the snow can freely be received and become engaged between adjacent ones of the blades 34. It was found that a bonus on efficiency can be obtained by circumferentially sloping the axially forward front edge 41 in the direction of rotation of the impeller 28. More specifically, each front edge 41 forms an angle θ1 of at least 85° relative to the corresponding tip 40. In certain embodiments, the angle θ1 can be of 90°. This axially forward front edge 41 can form, to a certain extent, a cupped area which can help impede/resist forward displacement of the snow accumulated against the tips 40 of the impeller blades 34. It was found that by providing such a cupped area, and with the front edge 41 extending circumferentially over a given arc, the amount of snow which is trapped by the cupping front edge 41 is not only greater, but the snow can remain trapped longer during rotation of the impeller 28, increasing the odds of snow being ejected outside the secondary housing via the chute which is located at a given circumferential position of the cylindrical wall 38.

A small gap 42 extending axially between the tip fence 48 and the front edge 41 is typically provided to avoid friction, but this gap 42 can be minimized to the extent feasible/reasonable. It can be desired to limit the amount of the gap 42 between the radial end tip 40 of the impeller blades 34 and the circumferential wall 38 of the secondary housing 18 by using tight tolerancing. The longitudinal clearance extending between the front edge 41 and an interior surface of the tip fence 48 can also be limited by design using tight tolerancing. Also shown in this embodiment, the tips 40 of the impeller blades 34, in the radially outer portion, are tapered and lead to a radially extending sharp edge 43, as best shown in FIG. 4. Indeed, using a sharp edge 43 at this region which is oriented circumferentially can allow to cleanly “catch” the incoming snow rather than push a small but potentially significant portion of it forward. In some experiments, it was found preferable to provide the tips of the impeller blades with a square edge (as opposed to, say, the sharp edge 43). In these embodiments, it was found that the catching of the incoming snow can be more efficient.

FIG. 5 presents an oblique view of the impeller 28 showing how the impeller blades 34 generally extend radially relative to the hub 36 and rotate around the impeller axis B. As depicted, the blades 34 have tips 40 forming radial ends and which are configured to almost touch the cylindrical wall 38 of the secondary housing 18. Although four blades 34 are shown in this embodiment, it is intended that the impeller 28 can have two, three, or more than four blades. In certain embodiments, the blades 34 are evenly distributed around the impeller axis B.

As best seen in the inset, the front edge 41 can have a first radial dimension r1 and the tip fence 48 can have a second radial dimension r2 smaller than the first radial dimension r1. The radial clearance extending radially between the front edge 41 and the tip fence 48 can be referred to as a third radial dimension r3 corresponding to the difference between the first radial dimension r1 and the second radial dimension r2, i.e., r3=r1−r2, plus or minus the gap 42 extending between the tip 40 of the blades 34 and the cylindrical wall 38. As such, considering that the front edge 41 of the blade 34 clears the tip fence 42 along the inward radial direction by at most half of the first radial dimension r1, it is considered that the third radial dimension r3 is given by r3<50%·r1. In some embodiments, the front edges 41 radially clear the tip fence 48 by at least a quarter of the first radial dimension r1, i.e., r3>25%·r1. In some preferred embodiments, the front edges 41 radially clear the tip fence 48 by a third of the first radial dimension r1, i.e., r3≈33%·r1.

As shown, the cylindrical wall 38 has a diameter D. In some embodiments, the third radial dimension r3 can range between about 0.25 inch and 1 inch. However, in some experimental tests, a dimension of about 0.50 inch for the third radial dimension r3 was found to be satisfactory, especially in the case of personal snow blowers. For industrial snow blowers, the third radial dimension r3 can correspond to 0.625 inches, depending on the embodiment. In some embodiments, the second radial dimension r2 of the tip fence 48 is given by a relation involving the diameter D. For instance, the second radial dimension r2 can correspond to the given diameter divided by a given number N, with the number N varying between 12 and 20, preferably varying between 13 and 18, and being most preferably 15. As such, in embodiments where the diameter D is 30 inches, then the second radial dimension r2 can be 2 inches. In these embodiments, the first radial dimension r1 preferably ranges between 2.25 inches and 2.625 inches. The second radial dimension r2 can vary between 1.5 inches and 2.5 inches in some embodiments.

It was found that during operation, the high velocity pushing of the snow generated by the tips 40 of the impeller 28 and the reacting force generated at the cylindrical wall 38 could lead to an axially forward and rearward forces acting on the snow. While the snow is trapped at the rear by a rear wall 46 of the secondary housing 18, some of the snow may end up being pushed back out, in the forward orientation, back into the primary housing, and potentially even across the primary housing and back out of the snow blower, representing an efficiency hurdle. In the illustrated embodiment, some elements can be provided to avoid or attenuate this effect. For instance, one of these elements is directed to the angles of the front edge's upper and lower edge portions relative to a radial orientation. More specifically, the front edge 41 circumferentially defines a first edge portion 41a which is located at a radially outward position and which faces the cylindrical wall 38. Moreover, the front edge 41 circumferentially defines a second edge portion 41b which is located at a radially inward position and which faces the impeller axis B. It is intended that the angle θ2 of the first edge portion 41a relative to the radially inward direction is less than 90° so as to avoid any friction with the cylindrical wall 38. Preferably, the angle θ2 is at least 85°, but preferably smaller than 90°. However, the second edge portion 41b can form an acute angle θ3 relative to the radially inward direction. In this specific embodiment, the angle θ3 is about 90°. In some other embodiments, the angle θ3 can be less than 90°, for instance about 85°. In any case, these values for the angle 03 ensure that snow reaching the secondary housing passed the front edge 41 can be kept thereinside thanks to the suitable angling of the first and/or second edge portions 41a and 41b of the front edge 41.

FIG. 6 shows a side view of an example blade 34 having a portion fixedly attached or made integral to the hub 36. As depicted, the blade 34 has a radially end tip 40, an axially forward front edge 41, and an oblique edge 45 extending radially inwardly from the front edge 41 and extending rearwardly towards the hub 36. It was found that by reducing the first radial dimension r1 of the front edge 41, the angle at which the oblique edge 45 can be increased to a relatively significant extent. For instance, in this embodiment, the angle θ4 of the oblique edge 45 relative to the longitudinal orientation is of preferably 35° or lower. In certain embodiments, the angle θ4 of the oblique edge 45 can range between 25° and 40°. Such an angled oblique edge 45 can add structural strength to the blade 34, which has a smaller front edge. In some embodiments, the oblique edge 45 extends as close as possible to the hub 36. For instance, the oblique edge 45 can extend radially inwardly for at least 75% of a radial dimension of the corresponding blade 134. The size and shape of the oblique edge 45 can vary from one embodiment to another. For instance, the oblique edge 45 can bottom at about half of the radial length extending between the center of the hub 36 and the radial tip of the blade 34. FIG. 7 shows how the front edge 41 circumferentially slopes in a direction of rotation of the impeller, and by doing so forms an angle of at least 85° relative to the corresponding tip 40.

FIGS. 8 and 9 show another example of an impeller 128 rotatably mounted within a cylindrical wall 138 of a secondary housing 118. As shown, the front edges 141 of the blades 134 clear only a little the tip fence 148, thereby reducing the overall potential area where snow can hit and then fall back into the primary housing 112. As shown in this front view, the front edges 141 have corresponding first and second edge portions 141a and 141b which each form a corresponding angle θ2, θ3 relative to the radial orientation. Preferably, the angles θ2 and θ3 are the same angles, which is of at about 85° in some embodiments. In some embodiments, the angle θ2 can be more acute than that, and for example reach 45° or more. The angle θ4 of the oblique edge 145 relative to the longitudinal orientation is of preferably 35°.

FIG. 10 shows another example of a snow blower impeller 228, in accordance with an embodiment. As shown, the impeller 228 is configured for rotation around an impeller axis B when mounted to a corresponding snow blower's secondary housing (not shown). The impeller 28 has a hub 236 coinciding with the impeller axis B, a body 229 which extends from the hub 236 in a plane perpendicular to the impeller axis B, and blades 234 mounted to the rotating body 229. During use, the hub 236, the body 229 and the blades 234 rotate together around the impeller axis B. In this particular case, the body 229 has a pseudo-triangular shape providing support for the three blades 234. However, in some other embodiments, the body 229 can have any other shape including, but not limited to, a circular shape, and the like. The body 229 can be omitted in some other embodiments.

As shown in this specific example, the blades 234 do not extend radially outwardly straight from the hub 236 as in the other examples described above. Rather, the blades 234 extend, from corresponding spaced apart circumferential position, inwardly away from the impeller axis B. The blades 234 thus form an angle relative to the radial orientation. It was found that these slanted blades 234 can better force the snow radially outwardly as the impeller 228 rotates, which ultimately help in guiding the snow towards the chute (not shown) in a more efficient manner. More specifically, in this embodiment, the blades 234 have a distal section 234a which forms a first angle α1 with regards to the radial orientation. Moreover, the blades 234 have a proximal section 234b made integral to the first section 234a. As shown, the proximal section 234b forms a second angle α2 with regards to the radial orientation. In this example, the second angle α2 is greater than the first angle α1. For instance, the first angle α1 can range between 5° and 25°, and the second angle α2 can range between 10° and 35°, depending on the embodiment. It is understood that the front edges 241 of the blades 234 touch the snow first as the impeller 228 rotates, leaving the snow to be guided radially outwardly by the distal section 234a and then by the proximal section 234b towards the circumference of the impeller 228.

In some embodiments, it was found beneficial to provide the oblique edge 245 of the blades 235 with a convex protrusion or shape 247, as best shown in the side view of FIG. 11. More specifically, the convex protrusion 247 has a first angle β1 extending between the oblique edge 245 and a hypothetically linear oblique edge at a radially distal location. The oblique edge 245 forms a second angle β2 between the oblique edge 245 and the hypothetically linear oblique edge at a radially proximal location. In this specific embodiment, the convexity is greater at the radially distal location than at the radially proximal location. More specifically, the first angle β1 is greater than the second angle β2. In some other embodiments, the first angle β1 can be equal to or smaller than the second angle β2. Depending on the embodiment, the first angle β1 can range between 1° and 15°, and the second angle β2 can range between 1° and 10°. It was found that the convex protrusion 247 can help the snow glide along the oblique edge 235 as the impeller 228 is moved forwardly, thereby reducing the risk of snow falling back into the primary housing.

Referring back to FIG. 2, the flights 30 can be provided with teeth 31 and oars 31′. For instance, as shown, the flights 30 have outwardly protruding teeth 31 which are spaced apart from one another along a spiral path of the flights 30. As shown, the outwardly protruding teeth 31 can have a prismatic shape which has a thickness corresponding to the thickness of the flights 30. The outwardly teeth can be made integral to the flights 30 or alternately be mounted (e.g., soldered) to the flights 30. Also shown in this embodiment, the flights 30 can be provided with angularly disposed oars 31′ which form an acute angle relative to the flights 30. In this specific embodiment, the oars can form an angle ranging between about 50° and 90°, preferably between about 50° and 58°, and most specifically of about 53°. It was found that using such angularly disposed oars, snow caught by the auger can be trapped and moved better within the secondary housing.

Referring now to FIG. 12, another example of a toothed flight is shown. As depicted, there is shown an exemplary auger having a helical pushing segment or flight 330, in accordance with another embodiment. As shown, the auger 330 has teeth 331 which protrude axially from the auger 330 and which are spaced from one another along a spiral length of the flight 330. FIGS. 13 and 14 show yet other tooth configuration examples. More specifically, FIG. 13 shows a flight 430 from which a tooth protrudes both axially along the auger and radially outwardly from the flight 430. In contrast, FIG. 14 shows a flight 530 having a tooth 531 protruding only axially along the corresponding auger. It was found that, thanks to experimental testing, the teeth 31, 331, 431 and 531 can help the flight move through hard snow and/or break ice more easily at least in some circumstances. The teeth 331, 431 and 531 can also favourably enhance the pushing of the snow towards the center of the auger. In some embodiments, the teeth can protrude of about 0.5 inch along the axial orientation of the auger, as best shown at dimension 433 in FIG. 13. Moreover, it was found that by preventing the teeth 331 and 531 to protrude radially outwardly from the corresponding auger, such as shown in FIGS. 12 and 14, undesirable damage made to the pavement or roadway can be greatly reduced. The number of teeth can vary depending on the embodiment. However, it was found that eight teeth, preferably nine teeth, and most preferably 12 teeth, which are circumferentially spaced apart from one another provide satisfactory results. The circumferential spacing between consecutive teeth can be even or uneven, depending on the embodiment. In any way, if too many teeth are used, it was found that moving through snow and/or breaking ice could be undesirably impeded.

As can be understood, the examples described above and illustrated are intended to be exemplary only. It is encompassed that the efficiency enhancing elements discussed above can be included individually in some embodiments, it can be preferred to combine them in any suitable sub-combination, and even combine them all, in other embodiments, such as the ones illustrated in this disclosure. The scope is indicated by the appended claims.