US2236815A - Collecting and conveying apparatus for sweepers - Google Patents

Description

' April 1, 1941. 3, EVANS 2,236,315

. COLLECTING AND CONVEYING APPARATUS FOR SWEEPERS Filed May 12, 1938 4 Sheets-Sheet 1 FE UP jean/4&0 ashrwrzrnm April 1, 1941. c, EVANS 2,236.815

COLLECTING AND CONVEYING APPARATUS FOR SWEEPERS Filed May 12, 1938 I 4 Sheets-Sheet 2 fan/A40 CZEMEA/ lT/AMS.

April 1,- 1941. R. c. EVANS I COLLECTING AND CONVEYING APPARATUS FOR swEEPERS Filed May 12, 1938 4 Sheets-Sheet 3 2 0M940 Cisasivrlhm R. c. EVANS 2.236.815

COLLECTING AND CONVEYING APPARATUS FOR SWEEPERS April 1, 1941.

Filed May 12, 1938 4 Sheets-Sheet 4 FE 52- 490/0910 (z'ewwrlkmr Patented Apr. 1, 1941 COLLECTING AND CONVEYING APPARATUS FOR SWEEPERS Ronald Clement Evans, Elgin, 111., assignorito Elgin Sweeper Company, Elgin, 111., a. corporation of Illinois Application May 12, 1938, Serial No. 207,445

8 Claims.

This invention relates to a street sweeping apparatus, and more particularly to novel collecting and conveying means for sweepers.

The subject matter hereof is related to that of my copending applications Serial Nos. 207,443, 207,446, and 216,740, the first two of which were filed on May 12, 1938, and the latter of which was filed on June 30, 1938.

Many forms of street sweeping apparatus have been employed in the past for cleaning streets and other surfaces to be swept. The different forms of sweeping apparatus may be roughly classified as caterpillar brush sweepers, rotary brush sweepers, and combined rotary brush and conveyor sweepers. The greatest difficulty in the design of any of these sweepers lies in the fact that a sweeping apparatus which is particularly well suited for sweeping dirt and other finely divided debris has not in the past been particularly efiicient in sweeping leaves, twigs, stones, refuse, and other similar forms of debris; while sweeping apparatus which has been designed to sweep leaves and other similar debris efficiently has not been particularly well suited for sweeping dirt and finely divided debris. It is believed that the reason for this lies in the fact that an efficient dirt sweeper requires a pick-up plate or drag plate disposed in front of the brush with its bottom edge very close to the surface bein swept, while an efficient sweeping apparatus for picking up leaves and the like requires some means which will permit the leaves to pass to the brush, or in other words, a construction in which the pick-up plate or drag is not disposed very close to the surface being swept. In the first instance referred to above, the leaves are pushed ahead of the sweeping apparatus and for that reason do not come into contact with the sweeping brush. Where the pick-up plate .or drag plate is high enough to permit leaves to pass thereunder, the sweeping apparatus throws the dirt underneath the plate and for that reason it is not swept up.

It is an object of the present invention to provide novel means for sweeping streets and the like which is efllcient in picking up both types of debris referred to above. I

Another object of this invention is to provide novel means for cleaning streets which includes r A further object of this invention is to provide a novel sweeping apparatus employing novel collecting and conveying means. I

A still further object of this invention is to pro vide novel means for accumulating and picking up debris.

Another and further object of this invention is to provide novel means for segregating debris into two classes and for continually sweeping one of the segregated classes of debris but only intermittently sweeping the other segregated class of debris, the second class of debris being pushed ahead of .the sweeping apparatus during the interval when it is not permitted to pass to the sweeping brush.

Another and still further object of this invention is toprovide 'a novel drag plate and dra plate mounting for street sweeping apparatus and the like. 7

Still another and further object of this invention is to provide a novel actuating mechanism for periodically raising and lowering a drag plate employed in a street sweepingapparatus.

Another and further object of this invention is to provide a novel collecting and conveying apparatus for sweepers which is economical to manufacture, which is rugged and reliable in use, and which is extremely efficient in operation.

The novel features which I believe to be characteristicof my invention are set forth with particularityin the appended claims. My invention itselflhowever, both as to its construction and organization, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings in which:

Figurel is a side elevational view of a street sweeping apparatus employing a caterpillar brush and a periodically oscillated drag plate;

Figure 2 is an enlarged fragmentary elevational view illustrating the lower end of the caterpillar brush assembly and the drag plate which cooperates therewith;

Figure 3 is a greatly enlarged cross-sectional view of the drag plate and drag plate mounting.

Figure 7 is a view similar to Figure 6 but shows the drag plate carriage in its upper position; and Figure 8 is a detail view similar to Figure 3 showing the spring for positively lowering the drag plate to its lower position.

The sweeping apparatus illustrated in Figure 1 of the drawings is a street sweeper of the caterpillar brush type. The sweeping elements of this apparatus together with their associated elements are mounted on a motor driven vehicle II], the principal component parts of the complete apparatus being a caterpillar brush assembly II, a dirt and debris storage hopper I 2, and a chassis I-3 having a rear mounted motor I4 thereon (the motor being diagrammatically indicated by showing the customary hood enclosing the same). The chassis I3 includes a pair of front wheels I5 mounted on a fixed axle (not shown) and a pair of rear wheels I8 which are preferably mounted closely together on a pivotally mounted steering assembly I1. Steering assembly I1 is connected through any suitable connecting mechanism to a steering wheel disposed in the drivers compartment or cab I8.

To enhance the general appearance of the vehicle I0 and to protect the sweeping apparatus from the elements, a body I9 is provided which forms a continuation of cab I8 and which may be given any shape which will further enhance the general appearance of the vehicle. upper forward wall of the body I9, a relatively large transverse opening is provided to permit access to the upper portion of the caterpillar brush assembly IL This transverse opening in the upper forward wall of body I9 is closed by a sliding cover which is held in desired position by a pair of flange members 2| welded or otherwise suitably secured to the top of body IS. the flanges 2| being so arranged as to permit transverse sliding movement of the cover 20.

The dirt and debris collecting hopper I 2 is situated at the extreme forward end of the vehicle IE] and communicates directly with the upper portion of the brush assembly II. Hopper I2 is designed to receive dirt and debris carried upwardly thereto by the sweeping apparatus and to store the same until it is desired to empty the hopper I2. Lower end .wall 22 of the dirt and debris collecting hopper I2 is pivotally mounted to the end of chassis I 3 by a pair of hook shaped arms 23 which are pivotally secured to the horizontal frame members of the chassis I3 as at 24.

In order to hold the end wall 22 of hopper I2 in its closed position so as to prevent escape of dirt and debris from the hopper, a flexible cable 1 or chain 25 is employed to hold end wall 22 in place. Chain 25 is connected at one end to end wall 22, is then passed over a sheave 26 secured to the side wall of the body I9, and is connected finally at its opposite end to a dump lever 21. The dump lever 21 is pivotally mounted on the body I9 as at 28, its downward angular movement being limited by a suitable stop means (not shown) to the position shown in Figure 1. In this position the lever is in an overcenter position which automatically locks the end wall in its closed position. When dump lever 21 is moved upwardly and forwardly, the forward movement of the flexible cable or chain 25 permits the end wall 22 to open by virtue of its own weight.

The caterpillar brush assembly I-I includes in general a caterpillar brush 29, and a caterpillar brush housing 30 composed of an upper stationary housing portion 3| and a lower movable housing portion 32 arranged with limited angular move- In the caterpillar brush chains 55 ride.

men-t about a transverse axis. More specifically, lower housing portion 32 is hinged to and supported by upper housing portion 3| as at 33. The rear Wall 34 of housing portion 32 is preferably given a segmental cylindrical curvature, and the lower end 35 of the top wall of the upper hous ing portion 3| is similarly curved but arranged to permit the lower housing member 32 to be telescoped thereover. The side walls of lower housing member 32 overlap the side walls of upper housing member 3| even when the former are in their lowermost position. This substantially completes telescopic engagement of the lower housing member 32 with the upper housing member 3|, and permits the former to be raised and lowered without any substantial interference from the latter.

In order to permit ready accessibility to the caterpillar brush 29 to repair or replace a portion thereof, the rear Wall 34 includes a pivotally mounted panel 35 which preferably extends over a major portion of the rear wall 34.

The caterpillar brush assembly I I also includes a pair of dirt shoes 31 carried on the lower housing portion 32 by arms 38, the latter being pivotally connected to shoes 31 as well as to the housing portion 32. Dirt shoes 31 are in the form of runners which ride along the street surface, the forward and rear ends 35 and being turned up for that purpose. These shoes prevent dirt and other debris from being thrown out the sides of the sweeping apparatus. A stop block 4| on each side of housing portion 32 engages the arms 33 when the housing portion 32 is raised and this carries the shoes 31 up with it. The general and specific nature of dirt shoes 31 is described in claims in my copending application Serial No. 207,446, filed May 12, 1938, and assigned to the same assignee as the present invention.

In order to provide continuous and efllcient sweeping irrespective of ripples and the like in the street surface, a fioatnig mount 42 is provided for caterpillar brush 29. This floating mount has the effect of permitting the lower end of the caterpillar brush 29 to float on the surface being swept. The novel features of this floating mount are described and claimed in my aforesaid copending application.

More specifically the caterpillar brush floating mount 42 comprises a pair of tracks 43 and 44 which are mounted in parallel spaced relationship on both sides of the lower housing portion 32. The tracks 43 and 44 may be provided by employing offset flange members which are welded or otherwise suitably secured to the sides of housing portion 32. Portions of the housing wall be tween the complementary track members 43 and 44 are cut away as at 45 and 45 to permit free movement of the caterpillar brush supporting means which extends therethrough. A caterpillar brush supporting plate 41 having small wheels or rollers 48 and 49 is disposed between each pair of complementary tracks 43 and 44, the wheels or rollers 48 and 49 being arranged to ride in tracks 43 and 44 respectively. It will thus be understood that caterpillar brush supporting plate 41 is mounted for limited movement along a line parallel to the tracks 43 and 44.

Secured to the lower portion of supporting plate 38 are two bearings 50 and 5| which are adapted to receive and have journalled therein sprocket axles 52 and 53. Sprocket axles 52 and 53 each carry a pair of sprocket wheels 54 (see Figure 2), .over which two endless articulated At the upper end of the assembly the two endless 55 ride on sprocket Wheels (not'shown) which are similar to sprocket wheels 54 and which are carried on a sprocket axle 56.

Since the position of the lower end of the caterpillar brush 29 is defined by the position of the axles 52 and 53, it will readily be perceived that the position of the lower end of caterpillar brush 29 depends upon the relative position of the brush supporting plate 41 in the complementary brush supporting plates 41. One means for pro-' viding such a counterbalance isshown in Figure 1, wherein counterweights 51 are provided on;

opposite sides of the vehicle l and are pivotally; supported from the chassis l3 by means of counterweight arms 58, the counterweight arms;

being pivotally mounted on the support brackets 59 at an intermediate point in their length as at 60. The counterweight arms 5| each have an.

overhanging portion 6| which pivotally carries" length of each link arm may be adjusted at the will of the operator of the machine. A position index may be provided by employing an index. scale 64 on the lower housing portion 32 and a pointer 65 on the plate 41.

From the above description it will be apparent that the greater part of the weight of the caterpillar brush 29 is released from the brush fibres. The counterweights 51 are preferably adjustedon their arms 58 until the force tending to lift the caterpillar brush 29 off of the street ape proaches but does not quite equal the weight which the brush fibres of the brush 29 must support. Previous mention has been made of the fact that lower housing portion 32 is pivotally mount.- r

ed for limited angular movement on upper hous ing portion 3!. Some means must of course be provided for limiting downward movement of. the housing 32 and for raising and lowering the same at the will of the operator. The means for raising housing 32 must include means for ra1s ing caterpillar brush 29 at the same time. Ac-

cordingly a flexible cable orchain 66 is provided for defining the lowermost position of housing 32 which is connected at one end to the housing 32 as at 61 and at the other end to the chassis l3 as at 68. 1

Additional means is provided for raising and lowering the entire caterpillar II. More particularly, the caterpillar brush 29 and the caterpillar brush lower housing 32 may raised or lowered by means'of a flexible cable or chain 69 which branches ofi into two lower chain portions 10 and 'H which are connected to the caterpillar brush housing 32 and the caterpillar brush supporting plate 41 respectively. The upper end of chain 69 is connected to a crank arm 12' of a control lever 13 which is pivotally mounted on the chassis l3 asv at 14; Control lever 13 is preferably equipped with the usual spring bias latch (not shown) under the" brush assembly control of the control lever latch release I5, the latch being arranged to engage a cooperating notched latch plate 16 mounted on the side of the vehicle. As shown in Figure 1 of the drawings, when control lever 13 is in its forward position, the caterpillar brush assembly H is in its lowermost position, while when control lever 13- is in its rearwardmost position, the caterpillar brush 29 and the caterpillar brush housing 3?.

have been lifted by the chain 69'to a raised position.

A caterpillarbrush tensioning device 11 is provided to take up slack in the endless articulated chains 55 of the caterpillar brush assembly H and to provide the desired amount of tension therein. As will readily be appreciated from a cursory examination of Figure l, the deg-ree'of" tension in the endless chains 55 can be governed by varying the relative spacing of the upper sprocket axle 56 from the two lower sprocket axles 52 and 53. Thus, if some meansis provided for varying the distance between the upper sprocket axle 56 and the two sprocket axles 52 and 53, it is apparent that an adjustable tensioning arrangement will be provided. The specific means for accomplishing this end has been described in detail and claimed in my aforementioned copending application Serial No. 207,446, filed May 12, 1938, and assigned to the same assignee as the present invention.

The tensioning device 1! is provided by journalling the upper sprocket axle 56 in suitable bearings (not shown) carried on support plates 18 which are arranged to slide within complementary flange or track members 19 and 8!). These complementary track members 19 and are secured to the side walls of upper housing 3! in parallel spaced relationship to each other, but special note should be taken of the fact that the longitudinal axis of the track members'19 and 80 are not in parallelism with the longitudinal axis of the track members 43 and 44. While the angle of divergence of the longitudinal axis of the two sets of track may vary within wide limits without departing from the spirit and scope of the present invention, the angle is illustrated in Figure 1 of the drawings as being approximate- 1y 20, the lower ends of the track members being further apart from each other than their upper ends. Due to the fact that the longitudinal axis of the track members 19 and 80 is disposed at an angle with respect to the longitudinal axis of track members 43 and 44, it will readily be appreciated that by raising and lowering the support plates 18, the tension in the endless chains 55 may be adjusted. This is by virtue of the fact that as the plate members 18 are lowered in' track members 19 and 89, the distance between the upper sprocket axle 56 and the two lower sprocket axles 52 and 53 is increased. The position of the support plates 18 in the tracks '59 and l 80 is determined by clamping bolts 8! which are mounted in collars 82 to upper housing 3|. A

. position index is preferably employed by providing an index scale 83 on the sides of the housing opposite each lower track '19 and by providing a pointer 84 on the movable plate 78 of each tensioning device 'I'I Power for driving the caterpillar brush 29 is axle 56, the necessary drive chains 81- and sprocket wheels 89 and 99 being provided for this purpose.

Power for driving the vehicle itself is obtained from the motor I4 through a second pair of drive shafts 99, one on each side of the vehicle, and a pair of drive chains 9|, the usual bevel gear boxes being provided at 92.

As may be seen best in Figure 2 of the drawings, the caterpillar brush 29 is preferably made up of a plurality of individual brush units 93 which are detachably and individually secured to the articulated chains 55. eludes in general a brush head 94 and a brush proper or fibre portion 95, which is made up of a multitude of individual fibres composed of any suitable material, such for example as bamboo fibres.

The novel features and specific characteristics of this caterpillar brush and mounting are described in detail and claimed in my copending I a caterpillar brush, two separate and distinct Each brush unit 93 inapplication, Serial No. 216,740, filed June 30, 1938,

and assigned to the same assignee as the present invention.

During the sweeping operation, the caterpillar brush 29 is driven in a counterclockwise direction from the upper sprocket axle 56. The individual brush units 93 as they pass over the surface being swept cause the dirt and debris to be thrown forwardly and upwardly. In order to convey the dirt and debris upwardly to a point where it may be deposited in the hopper I2, an inclined plane 96 must be provided immediately below the ends of the brush fibres 95. This inclined plane 96 forms the bottom wall of the brush housing portions 3I and 32, although it is spaced from the lower edges of the side walls of housing portions 3| and 32.

In order to get the dirt and debris onto this inclined plane 96, it is necessary to cause the lower end 91 of the inclined plane 96 to diverge slightly away from th brush fibres 95 to provide a throat into which the dirt and debris may be thrown by the brush. The upper portion 98 of the inclined plane, however, is preferably in direct contact with the lower end of the brush fibres 95. This novel caterpillar brush and brush assembly is described in detail in my aforementioned copending application No. 207,4 i6.

Extending downwardly from the lower edge of the inclined plane 96 and forming substantially a continuation thereof is a drag plate 99. For a reason which will presently appear, drag plate 99 is mounted for limited longitudinal movement in a plane parallel to the lower end portion 91 of the inclined plane 96.

The particular mounting for the drag plate 99 may be seen best in Figures 3, 4 and 5, and includes a carriage I99 having a pair of cross bars IN and a pair of end bars I92. Rotatably mounted on each end bar I92 is a pair of flanged wheels I93. Housing 32 is suitably slotted at I94 for the reception of wheels I93, the major axis of the slots I 94 being parallel to portion 91 of inclined plane 96. Welded or otherwise suitably secured to the side walls of the housing 32 within slots I94 are a set of tracks I95 in which the I gage lower cross bar IN, is provided to prevent.

angular movement of the drag plate 99 below the plane of the portion 91 of the inclined plane problems must be overcome in order to have a satisfactory and efficient sweeping apparatus. Moreparticularly, it has been found that in order to sweep dirt and other finely divided debris the drag plate '99 must-be disposed relatively close to the surface being swept. When this is not done, there is hardly any effective pickup by the caterpillar brush of the sweeping apparatus, for the reason that the dirt is swept forwardly underneath the drag plate. By way of example it was found that when the drag plate was disposed withits lower edge approximately two inches above the surface being swept, there was little or no pickup-ability left in the sweeping apparatus; but when the drag plate was disposed with its lower edge approximately three-quarters of an inch above the surface being swept, the apparatus was very efficient in sweeping dirt.

If a drag plate is fixed in this position, however, it has :been found that the sweeping apparatus would not operate effectively to sweep up leaves and other debris of that character for the reason that the leaves would not pass under the lower edge of the drag plate, but would cause them to bepushed forwardly in front of it. Some means was necessary, therefore, to permit the leaves to pass to the caterpillar brush. One of the'important features of the present invention is the manner in which this is accomplished. More particularly, and in accordance with the teachings of the present invention, the drag plate 99 is periodically oscillated (that is, raised) to permit the leaves and other similar debris to pass. thereunder to the caterpillar brush 29. In order to maintain effective and efficient sweeping of dirt and other finely divided debris, it has been found preferable to provide a mechanism which will maintain the drag plate 99 in its lowermost position for a predetermined distance and to then effect a quick lifting and lowering of the drag plate 99.

The novel means for periodically raising and lowering the drag plate 99 includes a cam II9 of the wiper or involute type (see Figures 2, 6 and 7) which is centrally secured to a cam axle III that is journalled in bearings H2 and H3 secured to one side wall of the housing 32 and to a centrally disposed mounting bracket II4 respectively. Secured to the outer end of the cam axle III is a sprocket wheel I I5 which is driven by an articulated chain H6 from the drive shaft 85, a suitable gear reduction being provided in the gear box II'I so that the rate of rotation of the cam" H9 is relatively slow. The speed of rotationof cam II9 may, of course, vary within wide limits without departing from the spirit and scope of the present invention, it being simply necessary to adjust the cam speed so that the accumulation of leaves and other similar debris will not be unduly great.

The cam I I9 is positioned to engage a roller bar or cam follower II8 which is carried at the lower end of an L-shaped roller bar support arm I I9. Roller bar support arm H9 is centrally secured to the carrier I99, as may be seen best in Figures 2 and 4 of the drawings. From a careful inspection of the drawings it will at once .,be understood that the cam H9 will cause an upward movement of the carrier I00 along its tracks I95 during a small fraction of each revolution of the cam axle III. This upward movement of the carrier I00 causes the drag plate 99 to be periodically raised in a plane parallel to the lower portion 91 of the inclined plane 96.

The drag plate 99 is pivotally mounted on the carrier I90 in order that it may pass over large stones I and other heavy objects without damage to the apparatus as is clearly shown in Figure 6.

To operate the sweeping apparatus of the present invention, power is supplied to the upper sprocket axle which causes counterclockwise movement of the endless chains which carry the brush units 93. Due to the fact that the lower end of the caterpillar brush assembly 29 is freely floating on the surface which is being swept, the lower ends of the brush fibres are constantly in engagement with this surface. By

properly adjusting the counterbalance weight 51, substantially all of the weight of the caterpillar brush assembly 29 is removed from the fibres 95 themselves. The individual brush units 93 sweep the dirt and other finely divided debris upwardly and forwardly against the drag plate 99 where it is carried by the brush 29 upwardly along the inclined plane 99 until it passes over the open mouth l2l of the hopper I2.

Leaves and other debris of this character is pushed forwardly in front of the drag plate 99 by the drag plate itself until the drag plate is raised by the cam H0 in the manner shown in Figure 7 of the drawings. At this time leaves and other debris of this character pass under the lower edge of the drag plate 99 where they are thereafter swept forwardly and upwardly by the brush units 93 onto the inclined plane 90.

As the rotation of the cam H0 is continued, the drag plate 99 is returned to its lowermost position as shown in Figure 2 where it is again effective to catch and collect the dirt swept forwardly and upwardly by the individual brush units 93. During the interval that the drag plate is being moved upwardly and returned, the dirt and finely divided debris on the surface being swept is merely thrown forwardly ahead of the brushes until such a time as the drag plate is in its lowermost position, where the dirt and other finely divided debris is again caught and collected by the drag plate and caused to pass upwardly along the inclined plane 96 into the hopper l2.

The dirt shoes 31 slide along the surface which is being swept and prevent dirt and other debris from slipping out either side of the sweeping apparatus. These dirt shoes 31 thus prevent any impairment of efficient sweeping action by the apparatus.

After the storage hopper [2 has become filled, the dirt and debris collected therein may be dumped by throwing the dump lever 21 upwardly and forwardly thus causing the lower end wall 22 of the hopper l2 to open about its pivot 24. After the hopper I2 has been dumped, the end wall 22 is returned to its closed position by pulling the dump lever backwardl'y and downwardly until it has passed its overcenter position.

In traveling to and from the area to be swept,

the caterpillar brush assembly 29 and the lower brush housing 32 are elevated by pulling the control lever 13 to its rearward position (that is, to its left hand position as viewed in Figure 1 of the drawings).

From the above description, it will be apparent that I have illustrated means which is extremely effective in sweeping streets and the like. As will readily be apparent to those skilled in the art, dirt and finely divided debris is segregated from other debris such as leaves and the like. The dirt and finely divided debris is continually permitted to pass to the brush of thesweeping apparatus while the other debris, such as leaves,

is pushed forwardly, except for intermittent intervals, when it is permitted to pass to the sweeping brush along with the dirt and finely divided debris. It will further be apparent to those skilled in the art that the novel sweeping apparatus which has been illustrated and described herein is of a form which is economical to manufacture and rugged and reliable in use.

While I have designated my sweeper as a street sweeper, it is, of course, to be understood that I do not intend in the accompanying claims to limit the use of my sweeper solely for cleaning streets. It may be used with equal advantage in sweeping paved yards, warehouse floors, stadium floors, and numerous other similar surfaces where extensive sweeping operations are required.

A detail of my invention is shown in Figure 8, which discloses a view of the drag plate carriage held in its lower position by a spring device.

This spring'device, which holds the drag plate carriage in its lower position when not rocked upwardly by the cam H0, is designated generally by the reference numeral 200. As Figure 8 is a view similar to Figure 3 with the addition of the spring device 200, all other parts carry the same reference numerals in both figures.

Previous mention has been made of the novel means for raising the drag plate 99,-as shown in Figures 6 and '7. The spring device includes a pair of helical springs 20| which effect a positive lowering of the drag plate and supplement the force of gravity.' Each of these springs has one end 202 secured to the roller hanger l03a. by a lug 203 depending therefrom, and the opposite end 204 is hooked around a pin 295 which is secured to and carried by theside walls ofthe housing 32. The tension of the springs 20] holds the cam follower I 18 (shown in Figure '7) against the cam H0, resulting in a positive upward and downward movement of the drag plate as it is actuated by the cam.

While I have shown a particular embodiment of my invention, it will, of course, be: understood that I do not wish to be limited thereto, since many modifications may be made, and I therefore contemplate by the appended claims to cover all such modifications as fall within the true spirit and scope of my invention.

I claim as my invention:

1. In a sweeping apparatus, a brush, a drag plate disposed ahead of said brush in a plane at an oblique angle to the surface being swept, the lower edge of said drag plate being disposed close to but in spaced relation to the surface being swept, whereby dirt and finely divided debris can pass thereunder, but other debris is pushed forwardly by said drag plate, and means for intermittently moving said drag plate to raise it in said oblique plane to permit said other debris to pass thereunder.

2. In a sweeping apparatus, a brush, a drag plate disposed ahead of said brush in a plane at an oblique angle to the surface being swept, the lower edge of said drag plate being disposed close to but in spaced relation to the surface being swept, whereby dirt and finely divided debris can pass thereunder, but other debris is pushed forwardly by said drag plate, said drag plate being mounted in the sweeping apparatus for only an up and down sliding movement substantially in i said plane, and means for raising as well as enabling lowering of said drag plate.

3. In a sweeping apparatus, a brush, a drag plate disposed ahead of said brush in a plane at an oblique angle to the surface being swept, the lower edge of said drag plate being disposed close to but in spaced relation to the surface being swept, whereby dirt and finely divided debris can pass thereunder, but other debris is pushed forwardly by said drag plate, a drag plate supporting carriage, a plurality of tracks carried by said sweeping apparatus upon Which said carriage is mounted for movement therealong, the longitudinal axis of said tracks being substantially parallel to said oblique plane, said drag plate being pivotally mounted on said carriage for limited angular movement upwardly away from said oblique plane, and means for enabling the periodical oscillation of said carriage on said tracks.

4. In a sweeping apparatus, a caterpillar brush extending forwardly and upwardly from the surface being swept, a caterpillar brush housing having an inclined surface disposed immediately below and substantially in contact with an in? clined lower edge of said brush, the lower portion of said inclined surface diverging away from the surface of said brush to provide a dirt and debris receiving throat, and a drag plate movably mounted relative to said housing and forming a substantially continuous downward extension of said inclined surface, and means for moving said drag plate substantially parallel to said lower portion of said inclined surface.

5. In a sweeping apparatus, a caterpillar brush extending forwardly and upwardly from the surface being swept, a caterpillar brush housing having an inclined surface disposed immediately below and substantially in contact with an inclined lower edge of said brush, the lower portion of said inclined surface diverging away from the surface of said brush to provide a dirt and debris receiving throat, and a drag plate movably mounted relative to said housing and forming a substantially continuous downward extension of said inclined surface, and means for periodically raising said drag plate to permit leaves and other similar debris to pass thereunder into contact with said brush.

6. In a sweeping apparatus, a caterpillar brush extending forwardly and upwardly from the surface being swept, a caterpillar brush housing having an inclined surface disposed immediately below and in substantial contact with the inclined lower edge of said brush, the lower portion of said inclined surface diverging away from the surface of said brush to provide a dirt and debris receiving throat, and a drag plate movably mounted on said housing and forming a substantially continuous downward extension of said inclined surface, said drag plate having an upper and lower position, means for maintaining said drag plate in its lower position for a predetermined distance of travel of said sweeping apparatus, and means for raising and enabling lowering of said drag plate over a second predetermined distance of travel of said sweeping apparatus.

7. In a sweeping apparatus, an apparatus supporting chassis, a brush mounted on said chassis, a drag plate disposed ahead of said brush in an oblique plane, the lower edge of said drag plate being normally disposed close to but in spaced relation to the surface being swept, whereby dirt and finely divided debris can pass thereunder but other debris is pushed forwardly by said drag plate, a drag plate supporting carriage, a plurality of tracks, carried by said chassis upon which said carriage is mounted for movement therealong, the longitudinal axis of said tracks being substantially parallel to said, oblique plane, and an involute type cam mounted on said chassis is proximity to said carriage and arranged to be rotated during forward movement of said sweeping apparatus, a cam engaging roller bar mounted on said carriage and positioned to be engaged by said cam, whereby said drag plate is raised by said cam at intermittent intervals during the forward movement of said sweeping apparatus.

8. In a street sweeping apparatus including a power driven brush bearing on the surface to be swept, a collecting means in advance of the brush against which leaves, twigs, refuse, and debris is adapted to accumulate as the sweeper is advanced over the surface being swept, said collecting means being spaced slightly from the surface being swept so as to allow dirt to be continuously picked up off of said, surface by said brush, and driven means operative to release the collected debris to allow same to be swept up by said brush, said collecting means including a displaceable barrier element in advance of and spaced from the brush, said driven means including mechanism for displacing said barrier element out of the path of the accumulated debris at predetermined intervals in the forward movement of the sweeper over the surface being swept and without increasing the space separating said barrier from said brush.

RONALD CLEMENT EVANS.

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