US3805421A

US3805421A - Yieldable impeller for two-stage snow blower

Info

Publication number: US3805421A
Application number: US00308841A
Authority: US
Inventors: I Kamlukin; M Prevost
Original assignee: Simplicity Manufacturing Inc
Current assignee: SIMPLICITY MANUFACTURING COMPANY PORT WASHINGTON WI A CORP OF WI; SIMPLITICY MANUFACTURING Inc; Simplicity Manufacturing Inc
Priority date: 1971-01-13
Filing date: 1972-11-22
Publication date: 1974-04-23
Anticipated expiration: 1991-04-23

Abstract

A paddle wheel impeller, for, e.g., the second stage of a two stage snow blower, has relatively thick blades of rubber-like material. To prevent the blades from being flexed so sharply as to cause cracking at their front faces, each has behind it a rigid backing member that flatwise engages the rear face of the blade adjacent to its radially inner edge, thence curves rearwardly and radially outwardly away from the normal plane of the rear blade face.

Description

United States Patent 1191 Kamlukin et a1.

1451 Apr. 23, 1974 YIELDABLE IMPELLER FOR TWO-STAGE SNOW BLOWER [75] Inventors: Igor Kamlukin, Mequon; Michael T.

Prevost, Cedarburg, both of Wis.

[73] Assignee: Simplicity Manufacturing Co., Inc.,

Port Washington, Wis.

[22] Filed: Nov. 22, 1972 [21] App]. No.: 308,841

Related US. Application Data [63] Continuation of ser. No. 106,121, Jan. 13, 1971,

abandoned. I

[52] US. Cl 37/43 D, 302/38, 56/294 [51]- Int. Cl E0lh 5/00 [58] Field of Search 302/38, 49; 239/214, 223, 239/224; 37/43; 56/249, 294, D16. 19, DlG. 20; 15/230, 230.19

[56] References Cited UNITED STATES PATENTS 2,715,246 8/1955 Van Doorn 302/49 X 2,734,328 2/1956 Wood 56/DlG. 20 3,021,661 2/1962 Couberly 56/294 X 3,678,671 7/1972 Scarnato et a1 56/294 3,321,851 5/1967 Fisher 37/43 R X 3,580,351 5/1971 Mollen 37/43 E 3,334,429 8/1967 Price 37/43 R 2,104,881 1/1938 McLemore 302/49 X 2,984,872 5/1961 France 302/49 X 2,903,302 9/1959 Ross 302/49 Primary Examiner-Ernest T. Wright, Jr. Assistant Examiner-Eugene H. Eickholt [5 7] ABSTRACT A paddle wheel impeller, for, e.g., the second stage of a two stage snow blower, has relatively thick blades of rubber-like material. To prevent the blades from being flexed so sharply as to cause cracking at their front faces, each has behind it a rigid backing member that flatwise engages the rear face of the blade adjacent to its radially inner edge,thence curves rearwardly and radially outwardly away from the normal plane of the rear blade face.

2 Claims, 3 Drawing Figures This application is a continuation of our copending application Ser. No. 106,121, filed Jan. 13, .1971, now abandoned.

This invention relates to paddle wheel impellers for propulsion of non-fluid materials, and refers more particularly to an improved paddle wheel such as that used for the second stage of a two stage snow blower, capable of accommodating pieces of hard material such as stones and chunks of ice that may be mixed with softer material upon which the paddle wheel normally operates.

One means for effecting propulsion of relatively soft homogeneous materials is a paddle wheel impeller rotating in a chamber having inlet arid outlet openings. Various fluid pumps employ this principle, but it is also applicable to the propulsion of non-fluid semi-solid materials such as snow and of particulated solid materials such as sand.

The second stage of a two-stage snow blower offers an example of a paddle wheel impeller used for the propulsion of non-fluid materials. Such a snow blower is commonly powered by a single-cylinder gasoline engine, and is adapted for clearing sidewalks, driveways, parking areas and the like.

A two-stage snow blower has an auger which rotates on an axis that extends transversely to the normal direction of motion of the machine and has a forwardly opening hood embracing the auger. Behind the hood is a compartment in which a paddle wheel impeller rotates. The paddle wheel compartment is so communicated with the hood that snow is delivered to the paddle wheel by the auger. The paddle wheel throws the snow upwardly, discharging it'through a spout that opens from the top of the paddle wheel chamber.

In the operation of any such snow clearing machine it often happens that pieces of harder material, such as ice, stones and wood, are picked up along with snow. When these enter the paddle wheel chamber they can jam themselves between the blades of the paddle wheel and the adjacent walls of the chamber.

Heretofore the paddle wheels of snow blower second stages have had rigid blades, and any jamming of a stone or the like between a paddle blade and the chamber wall tended to stall the engine by which the machine was driven. Clearing the jam was troublesome and difficult because the interior of the paddle wheel compartment was accessible only through the relatively small diameter spout outlet or through the opening that communicated the chamber with the hood, which opening was partially blocked by the auger. In some cases a jam could also result in damage to the paddle wheel blades or to the compartment wall.

Having in mind these objectionable characteristics of prior paddle wheel impellers for two-stage snow blowers, it is a general object of this invention to provide such an impeller that is substantially non-jamming, and which can accommodate chunks of hard material by reason of the fact that its blades are made of resiliently flexible material.

The mere provision of resiliently flexible blades does not completely solve the problem, however. In the first place, the blades must have some degree of rigidity and stiffness, along with their flexibility, for if they are too floppy they will not be capable of exerting the force required to throw snow to a substantial height above the machine. To achieve the necessary stiffness without impairing flexibility, each blade must therefore have substantial thickness.

If a resilient blade is supported along one edge thereof and is caused to flex rearwardly by a force that is applied to it at some distance from that edge, the blade will normally bend to a small radius curvature directly adjacent to the zone of its support, while the remainder of the blade that is spaced outwardly from that edge will be bent to a relatively large radius. In the zone of the small radius bend the portion of the blade material that is adjacent to the outer radius of the bend is placed under a tension that isapproximately in inverse relationship to the radius of the bend and in direct relationship to the blade thickness. With a relatively thick blade, such as must be used for a snow blower paddle wheel, the fibres of the material that are adjacent to the front blade face are thus stretched to several times their normal length by a small radius bend, and hence they can be easily strained to the breaking point. When this happens, a crack begins to develop at the front face of the blade, near the line of its support. I

With additional and repeated rearward flexing of the blade this crack rapidly deepens until the blade fails.

. With these considerations in mind, it is another object of this invention to provide an impeller wheel of the character described having relatively thick, and therefore fairly stiff, blades of resiliently flexible material, and having means for preventing its blades from bending about a relatively short radius when they flex, although permitting them to flex rearwardly to the extent necessary to yieldingly accommodate pieces of hard material.

Thus it is the general object of this invention to provide a paddle wheel that is particularly well suited to serve as the second stage impeller of a two-stage snow blower, which paddle wheel is substantially nonjamming in the presence of large chunks of hard material and is capable of a very prolonged useful life without replacement of its blades.

With these observations and objectives in mind, the manner in which the invention achieves its purpose will be appreciated from the following description and the accompanying drawings, which exemplify the invention, it being understood that changes may be made in the specific apparatus disclosed herein without departing from the essentials of the invention set forth in the appended claims.

The accompanying drawings illustrate one complete example of the embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

FIG. 1 is a front perspective view of a two-stage snow blower embodying the principles of this invention;

FIG. 2 is a fragmentary view on an enlarged scale of the snow blower shown in FIG. 1, partly in side elevation and partly in longitudinal section; and

FIG. 3 is a perspective view of the paddle wheel of this invention.

Referring now to the accompanying drawings, the numeral '5 designates generally a two-stage snow blower which illustrates one application of the principles of this invention. The snow blower 5 is of the type used for clearing sidewalks, driveways and the like, and is powered by a small gasoline engine 6 that is mounted at the rear of the machine, over a pair of wheels 7 which may be drivingly connected with the engine in a known manner.

At its front the snow blower has a forwardly opening hood 8 in which an auger 9 is rotatable on a horizontal axis that extends transversely to the normal direction of movement of the machine and substantially parallel to the axis of the wheels 7. Shoes or skids 10 on each side of the hood, at the bottom thereof, are adapted to engage the surface and to cooperate with the wheels 7 in carrying the machine for its forward movement. Handles 11 on the machine, projecting rearwardly therefrom, enable an operator walking behind the machine to guide it.

As is well known, the auger 9 is drivingly connected with the engine through a suitable transmission (not shown). As the auger rotates, helical flights 12 on it propel snow upwardly and laterally inwardly, towards an opening 13 in the upper rear portion of the hood, midway between the sides thereof. It will be understood that the flights 12 at each axial side of the auger are pitched oppositely to those at the other side thereof in order to effect such. laterally convergent movement of 'the snow, and that the flights terminate short of the central portion of the auger.

Behind the hood there is a generally drum-shaped second stage chamber 14 in which a paddle wheel impeller 15 is rotatable about an axis parallel to that of the wheels and the auger. The opening 13 cornmunicatesthe interior of the hood with the impeller chamber 14 and is so shaped and located that the blades 16 of the paddle wheel can pass between the flights of the auger as the blades move through a forward portion of their orbits, to receive the snow that is driven toward the opening 13 by the auger.

The chamber 14 fits the paddle wheel impeller rather closely, so that the chamber and the impeller in effect cooperate to provide a pump that has the opening 13 as its inlet. The blades 16 of thepaddle wheel are of course so disposed as to face substantially flatwise to their direction of orbital motion.

The paddle wheel is connected with the engine by a transmission (not shown) whereby the paddle wheel is rotated in the direction to carry its blades downwardly and rearwardly as they move betweenthe auger flights, and the snow that they receive there is carried rearwardly around the bottom of the chamber 14 and is thence expelled upwardly through an outlet 18 in the top of the chamber that opens tov a spout 19. Snow is discharged through the outlet with a substantial upward momentum, and the spout guides it into a desired trajectory, the spout being adjustable in a known manner to control the obliquely upward angle of snow discharge and the direction of such discharge.

It is a feature of the paddle wheel impeller of this invention that its blades 16 are of resiliently flexible material. Rubber or a rubber-like material has been found very satisfactory. The blades are generally rectangular in outline and are relatively thick. For example, a rubber blade that is about 3% in. wide (measured parallel to the paddle wheel axis) and 3% in. long should be about l/2 in. thick to give it the necessary stiffness.

As shown, the paddle wheel has three blades, and its body portion comprises a simple triangular plate 20, to the center of which a tubular hub 21 is welded.

At each apex of the triangular plate there is welded a small securement plate 22, disposed normal to the plane of the triangular plate. Each securement plate flatwise overlies the front face of one of the blades in a zone adjacent to the radially inner edge of the blade, and it cooperates with a rigid backing member 23 in securing the blade to the plate 20.

Each backing member extends across the major portion of the width of the blade. It has a flat radially inner portion 25 that flatwise overlies the rear face of the blade opposite the securement plate 22, and has a radially outer portion 26 that curves rearwardly away from the normal plane of the rear face of the blade and performs the very important function of controlling the flexing of the blade.

Each blade has a pair of holes therethrough near its radially inner edge. These are aligned with corresponding holes in its securement plate 22 and in the flat portion 25 of its backing member 23; and through these aligned holes pass cap screws 27 that are secured by lock nuts 28. In this manner each blade is held in place on the triangular body, clamped between its secure ment plate and the flat part of its backing member.

Because each blade is thus clamped only along its radially inner marginal edge portion, the major part of the blade is free to flex rearwardly if a hard article such as a stick or a stone comes between it and a wall of the chamber 14. Such flexing of the blades of course prevents the paddle wheel from being jammed by such objects; but if the blade were not controlled in its flexing, it would bend sharply in a zone adjacent to the members between which it is clamped, with the result that it would crack and eventually fail, as hereinabove explained.

The curved radially outer portion 26 of the rigid backing member defines the minimum radius of curvature to which the blades can be forced in its flexing, as illustrated by the broken lines in FIG. 2. As herein shown, the radially outermost surface of this portion of the backing member corresponds to a longitudinal segment of a cylinder which is tangent to the normal plane of the rear face of the backing member and which has its axis a distance behind the blade and parallel to the axis of rotation of the paddle wheel. The radius of curvature of this surface is of course large enough to insure that no portion of the blade material will be stressed excessively when the blade is flexed to the maximum extent that the backing member permits.

It will be understood that the radially outer portion of the backing member need not have a curve of uniform radius, such as is here shown but its curve should be a smooth one and should be tangent to the normal plane of the rear face of the blade, and of course every part of its curvature should have a radius large enough to insure against excessive flexing of the blade. It is also important that the curved portion of the backing member extend through a sufficient number of degrees of arc to accommodate the maximum deflection to which the blade might be subjected.

From the foregoing description taken with the accompanying drawings it will be apparent that this invention provides a very simple and extremely durable paddle wheel impeller for nonhomogeneous materials, capable of yielding in the presence of chunks of hard material and thus well adapted to serve as the second stage impeller of a two stage snow blower.

Those skilled in the art will appreciate that the invention can be embodied in forms other than as herein disclosed for purposes of illustration.

The invention is defined by the following claims. We claim: l. A paddle wheel impeller for a two-stage .snow

. blower or the like, comprising:

A. a triangular plate; B. a cylindrical hub secured to the center of said plate with its axis normal to the surfaces of the plate, to mount the plate for edgewise rotation in one direction; C. three rigid securement plates, each bonded along one of its surfaces to an edge portion of the triangular plate, one near each apex thereof, said securement plates being normal to the surfaces of the triangular plate and facing substantially flatwise to its direction of rotation; D. three normallyflat resiliently flexible blades, each having a front face and a rear face, and each having a radially inner portion at which its front face flatwise overlies one of said securement plates and an outer portion projecting radially beyond its securement plate a substantial distance; E. three rigid backing members, one for each blade,

each backing member having I. a radially inner flat portion which flatwise overlies the rear face of said radially inner portion of the blade, and Y 2. a radially outer portion which is curved rearwardly away from the plane of the rear face of the outer portion of the blade in an arc of substantially larger radius than the smallest radius about which the blade is capable of flexing, and which defines the sharpest curvature that the blade can assume in its rearward flexing; and

F. screw fastening means extending through the inner portion of each blade and of its backing member and confining them in flatwise superimposed relation to one another and the securement plate.

2. A paddle wheel impeller for effecting movement of a material such as snow that is normally soft and substantially homogeneous but may be mixed with chunks of harder material, said paddle wheel impeller being r tatable in one direction about a defined axis and comprising:

A. a flat body having edges of uniform length that meet at equiangular corners;

B. a cylindrical hub secured to the body plate at its center, with its axis normal to the surfaces of the body plate, for mounting the body plate for edgewise rotation in said direction;

C. a plurality of normally flat resiliently flexible blades, one for each edge of the body plate;

D. a pair of clamping members for each blade,

1. each of said clamping members having a flat securement portion of a shape and size to overlie one face of only a portion of the blade,'leaving another portion of the blade projecting edgewise therebeyond in one direction, and I 2. one of said clamping members having another portion which is curved out of the plane of its securement portion in an arc of substantially larger radius than the smallest radius about which the blade is capable of flexing;

E. fastening means securing said clamping members for each blade to their blade with the flat securement portions of the clamping members flatwise overlying opposite faces of said one portion of the blade and with said other portion of said one clamping member opposing but curved away from said other portion of the blade to define the sharpest curvature that said other portion of the blade can assume in its flexing in one direction; and

F. means bonding to each of the edges of the body plate, near a corner thereof, one of the clamping members for each blade, with the securement portion of the bonded clamping member flatwise overlying the edge of the body plate and normal to the body plate, to dispose the blade substantially flatwise to the direction of rotation of the body plate, and with said other portion of said one clamping member curved away from the direction of body plate rotation.

and t UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No- 3 1805. 01 Dated Avril 23. 197

Inventor(s) Igor Kamlukin It is certified thatetror appears in the above-identified. patent hat said Letters Patent are hereby corrected as shown below:

Column 6 line 3 (Claim 2 para A line 1) v the word "flat" should be deleted.

Signed "and sealed this lOth day ofSeptember 197 (SEAL) Attest: v M C M- G N, R, T c. MARSHALL DANN Attesting Officer Commissioner of Patents R P041150 T T uscm m-oc scan-v05 1* ms. cove-min" mums cum: um o-su-m

Claims

1. A paddle wheel impeller for a two-stage snow blower or the like, comprising: A. a triangular plate; B. a cylindrical hub secured to the center of said plate with its axis normal to the surfaces of the plate, to mount the plate for edgewise rotation in one direction; C. three rigid securement plates, each bonded along one of its surfaces to an edge portion of the triangular plate, one near each apex thereof, said securement plates being normal to the surfaces of the triangular plate and facing substantially flatwise to its direction of rotation; D. three normally flat resiliently flexible blades, each having a front face and a rear face, and each having a radially inner portion at which its front face flatwise overlies one of said securement plates and an outer portion projecting radially beyond its securement plate a substantial distance; E. three rigid backing members, One for each blade, each backing member having 1. a radially inner flat portion which flatwise overlies the rear face of said radially inner portion of the blade, and 2. a radially outer portion which is curved rearwardly away from the plane of the rear face of the outer portion of the blade in an arc of substantially larger radius than the smallest radius about which the blade is capable of flexing, and which defines the sharpest curvature that the blade can assume in its rearward flexing; and F. screw fastening means extending through the inner portion of each blade and of its backing member and confining them in flatwise superimposed relation to one another and the securement plate.

2. a radially outer portion which is curved rearwardly away from the plane of the rear face of the outer portion of the blade in an arc of substantially larger radius than the smallest radius about which the blade is capable of flexing, and which defines the sharpest curvature that the blade can assume in its rearward flexing; and F. screw fastening means extending through the inner portion of each blade and of its backing member and confining them in flatwise superimposed relation to one another and the securement plate.

2. A paddle wheel impeller for effecting movement of a material such as snow that is normally soft and substantially homogeneous but may be mixed with chunks of harder material, said paddle wheel impeller being rotatable in one direction about a defined axis and comprising: A. a flat body having edges of uniform length that meet at equiangular corners; B. a cylindrical hub secured to the body plate at its center, with its axis normal to the surfaces of the body plate, for mounting the body plate for edgewise rotation in said direction; C. a plurality of normally flat resiliently flexible blades, one for each edge of the body plate; D. a pair of clamping members for each blade,

2. one of said clamping members having another portion which is curved out of the plane of its securement portion in an arc of substantially larger radius than the smallest radius about which the blade is capable of flexing; E. fastening means securing said clamping members for each blade to their blade with the flat securement portions of the clamping members flatwise overlying opposite faces of said one portion of the blade and with said other portion of said one clamping member opposing but curved away from said other portion of the blade to define the sharpest curvature that said other portion of the blade can assume in its flexing in one direction; and F. means bonding to each of the edges of the body plate, near a corner thereof, one of the clamping members for each blade, with the securement portion of the bonded clamping member flatwise overlying the edge of the body plate and normal to the body plate, to dispose the blade substantially flatwise to the direction of rotation of the body plate, and with said other portion of said one clamping member curved away from the direction of body plate rotation.