US 3221358 A
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Description (OCR text may contain errors)
Dec. 7, 1965 R. F. DICKSON HIGH-SPEED ROADWAY VACUUM CLEANER 4 Sheets-Sheet 1 Filed April 18, 1963 By 6MM mi irme/V516 Dec. 7, 1965 R. F. DICKSON HIGH-SPEED ROADWAY VACUUM CLEANER Filed April 18, 1963 4 Sheets-Sheet 2 fraai/5% Dec. 7, 1965 R. F. DlcKsoN HIGH-SPEED ROADWAY VACUUM CLEANER 4 Sheets-Sheet .'5
Filed April 1s, 1963 m i INVENTOR.
,ea/fa.; iam/50N @ML/W fraz/V514 HIGH-SPEED ROADWAY VACUUM CLEANER Filed April 18, 1965 4 Sheets-Sheet 4 BVM/M inve/V56 United States Patent O jui 3,221,35 HIGH-SPEED RADWAY VACUUIVI CLEANER Rufus F. Dickson, 525 Arboiado Drive, Fulierton, Calif. Filed Apr. IS, i963, Ser. No. 273,893 3 Claims. (Cl. I5 34i) The present invention relates to a roadway vacuum cleaner which is particularly adapted for cleaning a roadway surface while traveling at a high forward speed.
Most of the conventional vacuum cleaning apparatus is designed and adapted for stationary operation. In the vacuum cleaning of a rug, for example, some of the cleaning is accomplished while the vacuum cleaner is in a completely stationary position, and some is accomplished while the vacuum cleaner is moving in a horizontal direction, -but the rate of such horizontal movement of the vacuum machine is so slow that there is no significant interrelationship between that horizontal movement and the cleaning action which is accomplished by the machine.
Conventional street sweeping machines do not generally utilize a vacuum principle of operation, but accomplish their work by means of a rotating broom combined with a suitable elevating mechanism which is adapted to collect the sweepings from the broom and elevate them upward into an associated bin or hopper. It is only within the past few years that the vacuum principle of operation has been applied to large machines, primarily for the sweeping of airfield runways used by jet aircraft, where both the time required by the sweeping machines to traverse the runways, and the efiiciency of sweeping particulate material therefrom, are fairly critical. The design of such machines has taken very little, if any, account of their forward speed and its effect on the eiliciency of the sweeping operation, with the result that good sweeping eiciency has not been attainable at speeds greatly in excess of l miles per hour.
A definite need does exist, however, for vacuum cleaning machines capable of efiicient operation at high for- Ward speeds. On railroads, for example, it is not uncommon to have a serious safety hazard created by drifting sand or dust which covers the roadbed and tracks; but at the same time a hand cleaning operation is unduly expensive, and a slow traveling vehicle would interfere with through traffic. The desirability of having an emcient sweeping mechanism which could be incorporated into a special car, capable of operating at forward speeds up to 50 or 100 miles per hour, is therefore recognized.
In the cleaning of airfield landing strips it is also recognized as desirable to be able to complete the cleaning operation very rapidly, in order not to interfere with the use of the landing strip by aircraft taking off from or landing thereon.
A definite problem currently exists also with regard to the usage of street sweeping machines on automotive freeways. Automotive traffic on the freeways generally moves at speeds in the range of 45 to 65 miles per hour, While the conventional street sweeping machine moves at a speed of approximately 8 miles per hour. Highway authorities have conclusively determined that, despite the best warning and danger signals that can be given to the motorists using the freeways, the slow moving sweeping machines nevertheless constitute a serious traffic hazard and are responsible for a large number of accidents on the freeways every year. On the other hand, it is estimated by the highway authorities that a sweeping or vacuum cleaning machine capable of operating at a speed of 35 miles per hour or greater would substantially eliminate the traffic hazard which exists at the present time.
It will therefore be apparent that the main object and purpose of the invention is to provide a vacuum .cleaning machine which is adapted for operating at relatively high forward speeds, and which takes advantage of its forward speed to facilitate the cleaning operation rather than to interfere with it. The novel feature and principles of the invention are considered to be applicable to the cleaning of street or automotive freeway surfaces, of airfield runway surfaces, and also to a large extent to the cleaning of railroad roadbeds.
More specifically, with reference to a roadway cleaning machine adapted to travel at a high forward speed, and having a vacuum intake nozzle disposed at a predetermined, relatively fixed distance above the roadway surface, the present invention contemplates improvements in three separate and distinct aspects of the machine operation, as follows;
1. The means or apparatus located behind the intake nozzle, whose function it is to dislodge and pick up from the roadway surface particulate material already traversed by the intake nozzle, and to propel or convey the same in a forwardly direction so as to be then drawn into the intake nozzle.
2. Means or apparatus provided on each side of the intake nozzle to shield the aerodynamic iiow action thereunder, from the ambient atmosphere on each side of the machine; and more specifically, to accomplish this shielding despite unevenness in .the roadway surface being cleaned, and despite variations in the extent to which the ambient atmosphere is disturbed by the forward motion of the vehicle as the vehicle speed changes.
3. Means or apparatus disposed forwardly of the intake nozzle and adapted to facilitate the dislodgernent and picking up of particulate material when first encountered bythe intake nozzle.
Thus the further objects of the invention are to improve the structure and operation of a high-speed roadway vacuum cleaner in these respects.
The objects and advantages of the invention will be more fully understood from the following description, considered in conjunction with the accompanying drawings, in which:
FIGURE l is a side elevational View of a presently preferred embodiment of the invention;
FIGURE 2 is a traverse sectional view of the machine, taken on the line 2 2 of FIGURE l;
FIGURE 3 is an enlarged longitudinal sectional view, illustrating the intake assembly and adjoining parts of the machine, taken on the line 3 3 of FIGURE 2;
FIGURE 4 is a sectional plan view of the intake assembly taken on the line 4 4 of FIGURE 3;
FIGURE 5 is a further enlarged longitudinal sectional view of the intake assembly, taken on the line 5 5 of FIGURE 4;
FIGURE 6 is a traverse sectional view of the intake assembiy, taken on the line 6 6 of FIGURE 5;
FIGURE 7 is an enlarged side view of the intake assembly and auxiliary support carriage in their retracted position;
FIGURE 8 is a traverse sectional view taken on the line 8 8 of FIGURE 7; and
FIGURE 9 is a longitudinal sectional view of a modified form of intake assembly in accordance with the invention.
Referring now to FIGURE 1 of the drawing, a selfpowered vehicle 2t) is adapted to travel at high speed in a predetermined forwardly direction, having a conventional drivers cab 2l at the forward end of the vehicle and conventional forward and rear wheels 22, 23, respectively, shown as resting on a roadway surface 24 which is to be cleaned. In its longitudinal mid-section the vehicle 20 carries a fixed bin or enclosure 25, whose lower portion 26 provides a hopper for receiving an accumulation of 3 particulate material that is cleaned or swept from the roadway surface.
An elongated sweeping chamber 30 extends forwardly from the hopper 26, the front end of the sweeping chamber being downwardly turned to provide an approximately L-shaped longitudinal cross-sectional configuration. The lower front extremity 31 of the sweeping chamber provides an intake nozzle which is the principal operative portion of the roadway vacuum cleaner machine. It is necessary that the intake nozzle 31 by spaced in a predetermined, relatively xed distance above the roadway surface being cleaned; and for that reason the rearward extremity 32 of the sweeping chamber is pivotally coupled to the hopper 26. The intake nozzle 31 and front end of the sweeping chamber 30 are supported from an auxiliary support carriage 35, whose function it is to sense minor variations in the elevation of the roadway surface, and to move the intake nozzle small distances up or down accordingly.
In the operation of the vacuum cleaner the circulation of air is accomplished in a partially closed, and partially open, circuit. A powered fan 40 disposed at the forward end of vehicle has its rearward, low-pressure side conductively coupled to the top of the bin or enclosure 25. Baies 27 are provided at the upper end of the bin or enclosure 25, which greatly impede and therefore decelerate the flow of air toward the fan 4). It will be seen that the operation of the fan produces a partial vacuum at the intake nozzle 31, causing air to flow into the intake nozzle, upward through the sweeping chamber to the bin or enclosure 25, and thence through the baffles 27 toward the fan. It will also be seen that the discharge of air from the sweeping chamber 30 is in a rearward direction into the bin immediately above the lower portion 26 thereof, while the fan draws the air in a forward direction after it has passed upward through the baffles. The combination of the bailles and the reversal of the direction of ilow of the air causes entrained particulate material, of whatever density, to be rather effectively precipitated therefrom within the bin or enclosure 25, and thus to fall downwardly into the hopper 26.
Referring now to FIGURE 2 it will be seen that on the high-pressure side of the fan 40 a portion of the discharge air is released through parallel paths 41a and 4111 to a lter 42 and thence to the surrounding atmosphere. At the same time a substantial portion of the discharged air ilows downward through d-ucts 43a and 43b disposed on the respective sides of vehicle 20, and is recirculated as an incident to the vacuum cleaning operation, as will be described. The ducts 43a and 43h are a flexible construction and have their lower extremities coupled to what may be generally referred to as the intake assembly, which moves up and down with the auxiliary support carriage 35.
The structure and operation of the intake assembly will now be described with reference to FIGURES 3 to 6, inclusive. Referring rst to FIGURE 5, the intake nozzle 31 is vertically disposed and the partial vacuum therein tends to draw particulate material in a vertically upward direction from the roadway surface being cleaned. In the illustrated embodiment the spacing of the intake nozzle 31 above the roadway surface is approximately three inches, and the width of the intake nozzle in the direction of forward travel of the vehicle is approximately 21/2 inches. A short distance to the rear of the vacuum intake nozzle 31 there is an air blast nozzle 45, disposed at a downwardly directed angle of approximately 45. More specifically, the air blast nozzle 45 is inclined in such a direction that the air blast generated or discharged therefrom strikes the roadway surface 24 rather immediately below the intake nozzle 31. To the rear of the air blast nozzle 45 there is a conventional rotary brush 50 which en-gages the roadway surface. The brush 50 is drivingly rotated in a direction of rotation opposite to that of the wheels 2K2 and 23 of the vehicle 20, with the result that the effect of the brush is to dislodge from the roadway surface 24 particulate material which has already been traversed bythe intake nozzle 31, but without being picked up thereby. The brush 50, because of its direction of rotation, drives the dislodged particles in a forwardly direction as indicated by the arrow 51, so that they merge with and are picked up by the air blast stream that is discharged from the air blast nozzle 45. While the brush does not thrust all of the particles in precisely the same direction, their path of travel is in general tangential to the surface of the brush, and since the diameter of the brush is considerably greater than the spacing of air blast nozzle 45 above the roadway surface, the result is that the operation of the brush drives the particles in a very positive fashion directly into the air blast stream. The air blast stream, in turn, drives the particles in a positive fashion towar the area immediatey beneath the vacuum intake nozzle 31, by which they are then picked up and carried to the hopper.
As will best be seen in FIGURE 4, the intake nozzle 31 extends in the direction transverse to the forward travel of the vehicle, substantially the full width of the vehicle. The air blast nozzle 45 and the brush 50 extend the same transverse distance as the intake nozzle. On respective sides of this assembly there are vertical chambers 55a and 55b which have a substantial vertical dimension, and which also extend longitudinally of the vehicle from a point in front of the vacum intake nozzle 31 to a point in the rear of the brush 50. A similar chamber 55e extends across the rear of the brush 50 and is adjoining t0 and continuous with the chambers 55a, 55b. The chambers 55a, 55b, 55C receive a continuous stream of air from the discharge side of the fan 4t), and their function is to provide a continuous downwardly flowing curtain of air surrounding the operative portions of the intake assembly so as to protect them from the ambient atmosphere. As shown in FIGURE 5 the lower edge of the rear wall of chamber 55e is crimped slightly inwardly so that the rear air curtain 55c1 is discharge downwardly but at an inwardly inclined angle of approximately 15. In similar manner, as shown in FIGURE 6, the lower outside walls of the chambers 55a and 55b are slightly crimped inwardly, to incline the side air curtains 55:11 and 55121 inwardly of the vehicle at an angle of approximately 15. While the chambers 55a, 55b, and 55e have been illustrated as being of diameter comparable to those of air blast nozzle 45 and vacuum intake nozzle 31, it is preferred to restrict the discharge gaps for the air curtain to about SAB inch.
As best seen in FIGURE 3 the ducts 43a and 43h discharge into a common manifold 44 which is a part of the intake assembly, and from the manifold 44 air is discharged both through the air blast nozzle 45 and the air curtain discharge chambers 55a, 55b, 55e. Thus the pressure of the air discharge thnough all of these paths is determined by the available pressure from the output side of the fan, but the air blast nozzle 45 is intentionally provided with a lmuch larger opening than the air curtain discharge gaps so that it will carry a `substantially greater volume of air.
The illustrated embodiment of the invention represents an loptimum design for forward speeds of approximately 25 miles per hour. For higher forward speeds the width `of the vacuum intake nozzle, measured lengthwise of the vehicle, should be substantially increased; and the various air volumes `and pressure levels throughout the remainder of the machine are then re-adjusted accordingly.
Reference is now made to FIGURES 7 and 8 showing the intake assembly vand auxiliary support carriage in a raised 4or retracted position. A pivotal support 61 permits the pivoting of the rearward end of the sweeping chamber 30 relative to the main port-ion of the vehicle 20, while the intake assembly housing 62 is coupled through a collapsible support member 63 to the drivers cab, thereby permitting it to be raised above the roadway surface.
Auxiliary carriage 35 provides essentially .a three-point support for the intake assembly, including a pair of front wheels 36 spaced very close together in front of -t-he housing 62, and a pair of rear wheels 37 which are laterally separated by the full width of the vehicle 20.
A feature which is believed to have considerable significance is that the forward wall 62a of the intake assembly housing 62 extends in a vertical direction, presenting a flat vertical surface to the oncoming air encountered by the vehicle as it moves forward. This surface, in combination with the under portion of the cab of the vehicle 20, is believed to have the effect of progressively compacting the oncoming air into which the vehicle is moving, with the result that a downwardly directed high-speed stream of air flows onto the roadway surface immediately below and in front of the intake nozzle 31. This air stream, not specifically illustrated in the drawings, is believed to have an action similar to the air blast stream generated by the air blast nozzle 45 as shown in FIGURE 5 of the drawings. Furthermore, it will be noted that the air stream concentrated under the forward end of the vehicle as a result of forward motion of the vehicle is dependent upon the vehicle speed for its existence, and therefore varies to some extent with the forward speed of the vehicle.
Reference is now made to FIGURE 9 illustrating the intake assembly of a modified form of the invention. A vertically disposed vacuum intake nozzle 71 corresponds in structure and function to the vacuum intake nozzle 31 of the embodiment of FIGURE 1. An air blast nozzle 75 corresponds in structure and function to the air blast nozzle 45. To the rear of the air blast nozzle 75 is an additional air blast nozzle 80, inclined at an angle of about 20 from the horizontal, and whose function and purpose it is to dislodge particles from the roadway surface in the same manner as accomplished by the rotary brush 50 of the first embodiment. The nozzle 80 is preferably driven with compressed air at a considerably higher pressure level than the nozzle 75, with the result that particles dislodged by the blast stream from nozzle 80 are picked up from the roadway surface and carried into the blast stream generated by the nozzle 75, in the same manner as in the first embodiment of the invention.
The embodiment of FIGURE 9 also includes an inverted air scoop 85 disposed forwardly of the intake nozzle 71, and it is the function of the air scoop y85 to produce an additional air blast stream impinging on the roadway surface beneath the intake nozzle 71, but whose speed and intensity of impingment vary directly as a function of the speed of forward travel of the vacuum cleaner vehicle.
While not specifically illustrated, the intake assembly of FIGURE 9 is surrounded by an air curtain structure like that of FIGURE 4, which includes a continuous air curtain along each side and across the rear of the more operative portions of the intake assembly, for the purpose as previously described of protecting them from the ambient atmosphere encountered by the Vehicle.
The invention has been described in considerable detail in order to comply with the patent laws by providing a full public disclosure of at least one of its forms.
However, such detailed description is not intended in any way to lirnit the broad features or principles of the invention, or the scope of patent monopoly to be granted.
1. A roadway vacuum cleaner comprising, in cornbination:
a wheeled vehicle adapted to transverse the roadway in a predetermined direction of travel;
a vacuum intake nozzle carried -by said vehicle and disposed a predetermined, substantially xed distance above the roadway surface;
an air blast nozzle carried by said vehicle and disposed behind said intake nozzle for directing an air blast upon the roadway surface;
primary agitation means carried by said vehicle and disposed behind said air blast nozzle for dislodging heavy particles not picked up from the roadway surface when initially traversed by said intake nozzle;
a pair of air skirting means extending longitudinally of said vehicle on respective sides of said intake nozzle;
third air skirting means extending transversely behind said primary agitation means, said three air skirting means together providing a protected area within which the desired cooperative action of said intake nozzle, said air blast nozzle, and said primary agitation means, may take place without interference from the ambient atmosphere, and despite variations in the forward speed of the vehicle and unevenness in the roadway surface;
each of said air skirting means including a chamber having an elongated, relatively narrow opening dis posed at approximately the same elevation as the opening of said intake nozzle;
and means for supplying a curtain of air flowing continuously through said openings downwardly onto the roadway surface.
2. A roadway vacuum cleaner as claimed in claim 1 wherein each of said air skirting means is adapted to generate its curtain of air in a downwardly direction, but inclined somewhat inwardly of said protected area.
3. A roadway vacuum cleaner as claimed in claim 2 wherein the angle of inward inclination of each of said air curtains is approximately fifteen degrees.
References Cited by the Examiner UNITED STATES PATENTS 2,018,791 10/ 1935 Kern. 2,536,902 1/1951 Beckett 15-345 3,007,191 11/1961 Braun 15-340 FOREIGN PATENTS 534,953 4/=1922 France. 1,217,672 12/1959 France. 1,117,628 lil/1961 Germany.
3,134 2/1892 Great Britain. 755,381 8/1956 Great Britain. 808,026 1/ 1959 Great Britain.
WALTER A. SCHEEL, Primary Examiner.