US 2878508 A
Description (OCR text may contain errors)
March 24, 1959 w. D. SEDGWICK ET AL 2,
TRASH AND LITTER COLLECTING APPARATUS 2 Sheets-Sheet 1 Filed Sept. 27. 1952 llvvalvTo/as. WILL/HM 0.5506W/0K ERNEST F). 60/400 CARL LHSHBROOK BY THE/l? HTTORNEYJ. Heme/s, Kusc H, F O$TER& HARRIS March 24, 1959 w. D. SEDGWICK ET AL 2,878,508
TRASH AND LITTER COLLECTING APPARATUS Filed Sept. 27, 1952 2 Sheets-Sheet 2 I l I 1 1 l //v VENTO as. WILL/19M D. SEDe-W/cK ERNEST A. \SCHQD CHRL l/HLHSHBROOK BY THE/I? HTTORNY5.J I gnma/s, K/sch; F05 rm & Heme/s United States Patent 2,878,508 TRASH AND LITTER COLLECTING APPARATUS William D. Sedgwick, Whittier, Ernest A. Schad, Van Nuys, and Carl V. Lashhrook, Reseda, Califl; said Schad and said Lashbroolr assignors to said Sedgwick Application September 27, 1952, Serial No. 311,826 2 Claims. (Cl. l5354) This invention relates to a trash and litter collecting apparatus and, more particularly, to a trash and litter collecting apparatus which is incorporated in a trailertype vehicle to facilitate its being towed along highways, roads, and over other surfaces behind a self-powered vehicle.
With the rapid expansion of our road and highway systems, the number of cars on the highways has increased phenomenally, this phenomenal increase resulting in there being thrown along the sides of the roads and highways papers, cans, bottles, and other trash which, mingled with the leaves from the roadside plantings and the natural accumulation of other litter, produces conditions which are unattractive and which materially detract from the appearance of the side of the road 'or highway.
Since many of these roads and highways are not provided with curbings and have shoulders which are not smoothly paved, it is impossible to use conventional sweepers to remove the trash deposit from the roadside. Furthermore, it is impossible to delegate to the task of cleaning the roadsides the number of men which woul be necessary to do the job manually.
It is, therefore, a primary object of our invention to provide a trash collector which is incorporated in a trailer vehicle and is designed to be towed along the edge of a trash littered highway or other trash littered surface so that the deposits of trash and litter may be readily removed therefrom. Of course, although our invention is described as being utilized to remove trash deposited on the edges of highways and roads, it is obvious'that it can be utilized to remove trash and litter from other surfaces or to remove deposits of various sorts from various types of locations and our device is not limited to the specific task of cleaning the edges of highways and roads.
It is, therefore, another object of our invention to provide a trash and litter collector which is mounted on a trailer vehicle and which includes a body having a litter receiving compartment, said litter receiving compartment being connected to a duct which is, in turn, operatively connected to an engine-driven pressure reducing or vacuum inducing blower, the litter collecting compartment being so connected to the blower that the possibility of the heavier and larger components of the trash being drawn thereinto is eliminated. An associated object of our invention is the provision of a trash and litter collecting apparatus of the aforementioned character which includes a flexible tubing having one end connected to the litter collecting compartment and the other end disposable adjacent the surface being cleared of trash, the
litter collecting compartment also being connected to a pressure suction duct which is in communication with the aforementioned blower to induce a negative pressure in the litter collecting compartment whereby trash and litter will be drawn through the flexible tubing into the litter collecting compartment.
The flexible tubing utilized as a means for seeking out and collecting the trash and litter initially from the shoulders or edges of the highways, roads, and other surfaces is a rather bulky and unwieldy element and it is necessary to provide auxiliary support means to prevent the tubing from whipping in the air as the trash and .litter Faiented Mar. 24, 19 59 collecting apparatus is towed along behind its tow vehicle. Another object of our invention is the provision, in a trash and litter collecting apparatus of the aforementioned type, of a yoke assembly which is movably secured to the body of the trash and litter collecting apparatus and which includes resilient elements designed to counterbalance the weight of the flexible tubing to materially reduce the forces necessary to control the lower end of the tubing in its passage over a surface to be cleaned.
As the leaf and litter collector is towed behind a tow ing vehicle, the open end of the flexible tubing is'utilized to suck the trash and litter into the first and second litter collecting compartments and must be moved across the surfaces being cleared of trash and there is, therefore, provided in our invention control means designed to permit the manual manipulation of the lowermost end of the flexible tubing over the surface being cleared so that various objects of litter and trash deposited themupon may be selectively removed by the disposition of the open end of the flexible tubing thereover.
Since the trash and litter collecting apparatus is designed to travel at moderate rates of speed along the shoulders of roads and highways and other surfaces which are being cleared of litter, there is provided on the body of the apparatus a demountable chair structure in which the operator of the flexible tubing may be seated. Fur thermore, the chair structure is provided with means for supporting the above mentioned control means so that a portion of the weight of the lower end of the flexible tubing may be borne upon the chair structure, the operator of the apparatus being required merely to sustain the weight incidental to the translation of the lowermost end of the flexible tubing over a-surface being cleared .of trash and litter.
Since it is essential that the apparatus be operable from both sides so that either edge of a road or other surface may be cleared of litter, the aforementioned yoke means is movably mounted upon the body structure of the apparatus to permit the flexible tubing supported thereupon to be shifted from one side of the apparatusto the other so that the road on either side of the apparatus may be cleared. Furthermore, there is provided on either side of the body of the apparatus mounting means whichis designed to receive the aforementioned seating structure and which permits the seating structure to be mounted on a desired side of the apparatus to accommodate the operator thereof.
Other objects and advantages of our invention will be. apparent from the following specification and the accompanying drawings which are for the purpose of illustration only and in which:
Fig. 1 is a perspective view showing a trash and litter collecting apparatus constructed in accordance with our invention;
Fig. 2 is an enlarged fragmentary view showing the seating and associated structures of the trash and litter collector of our invention;
Fig. 3 is an enlarged fragmentary view of a pivot structure incorporated in the control 'arm of our invention;
Fig.4 is an enlarged fragmentary section of a seal incorporated in the apparatus of our invention;
Fig. 5 is an enlarged fragmentary view of a joint incorporated in the apparatus of our invention;
Fig. 6 is a transverse sectional view taken through the body of the trash collecting .apparatus of our invention', and
Fig. 7 is a side elevational view showing the manner] in which the body of the trash and litter collecting ap paratus of our invention may be 'pivotally moved upon the chassis thereof to permit the dischargeof trash and litter from the body thereof;
Referring to the drawings and particularly to Fig. 1 thereof, we show a trash and litter collecting apparatus constructed in accordance with our invention, the apparatus 10 being embodied in a trailer-type vehicle 11 which generally includes a chassis 12 and a body .13.
The chassis 12 is provided at its forward end with a tongue 15 which facilitates the attachment of the vehicle to a towing vehicle to permit the apparatus 10 to be drawn over and along a surface to be cleared of trash and debris. The chassis 12 is, of course, mounted upon ground contacting wheels 16 which facilitate its translation over the aforementioned surface.
The body 13, as best shown in Fig. 6 of the drawings, is of generally rectangular configuration and is divided in its interior by a transverse, frusto-conicalpartition wall 18 which thus separates the interior of the body into a first litter collecting compartment 20 and a second litter collecting compartment 21. The first litter collecting compartment 20 communicates by means of a first opening 23 in the transverse partition 18 with a duct 24, the duct 24 extending through the second litter collecting compartment 21 and having its intake end connected to the opening 23 in the transverse partition 18 and its exhaust end 25 communicating with the interior of the second litter collecting compartment 21. Mounted on the forward end of the chassis 12 adjacent the forward end of the body 13 is a power plant 27 which has operatively connected thereto a blower 29 which is enclosed in a blower housing 30, said blower housing 30 being connected intermediate the intake and exhaust ends of the duct 24 to cause a negative pressure to be imposed through the intake end of the duct communicating with the opening 23 in the transverse partition wall 18. The connection of the various sections of the duct 24 to the blower housing 30 will be described in greater detail hereinafter.
Formed in the transverse partition 18 is a second opening 32, the second opening having connected thereto the lowermost end of a vertical trash intake conduit 34. The trash intake conduit 34 extends through a centrally located opening 35 in the roof of the body 13 and is juxtaposed to the end of a movable trash intake conduit 36 which is provided at the end juxtaposed to the uppermost end of the conduit 34 with a laterally extending flange 37 which is receivable in an annular fitting 39 which secures the end of the conduit 36 relatively tightly to the end of the conduit 34 but nevertheless permits the rotation of the conduit 36 with reference to the conduit 34 in a manner to be described in greater detail below. The conduit 36 extends laterally beyond the sides of the body 13 and is provided with a depending outer end 41 to which is secured the upper end of a flexible tubing 43 whose lower end is disposable adjacent a surface being traversed by the apparatus 10 to remove deposits 45 from said surface, as best shown in Fig. 2 of the drawings.
Supported upon and spanning the roof of the body 13 is a ring-like structure 47 which provides an annular tubular track 48 engageable by guide and support means 50 for the movable trash intake duct 36. The guide and support means 50 is constituted by a depending supporting arm 51 to the lower end of which is secured a follower wheel 52 which engages the annular track 48 to permit the movement of the movable trash intake duct 36 in a circular path above the body 13 of the trash and litter collecting apparatus 10. Therefore, the flexible tubing 43 mounted on the depending portion 41 of the movable trash intake duct 36 can be suspended from opposite sides of the apparatus 10 to facilitate trash removal from areas on opposite sides of the apparatus 10 without the necessity for rerigging the flexible tubing 43 and by the mere rotation of the movable trash intake duct 36 in the fitting 39 on the roof of the body 13 and the rolling engagement of the track follower wheel 52 on the annular track 48.
The flexible tubing 43, as best shown in Figs. 1 and- 2 of the drawings, is partially supported for movement across a surface being cleaned by means of a yoke assembly 55, the yoke assembly 55 being constituted in part by a collar 56 having laterally and oppositely extending supporting arms 57 to which are secured the upper ends of oppositely disposed resilient members 60 which may be constituted by tension springs or equivalent expedients. The lowermost ends of the resilient members 60 are secured to a yoke collar 62 which encompasses the flexible tubing 43 adjacent its lower end and thus permits the yoke assembly 55 to counterbalance the weight of the flexible tubing 43 in a manner which will be described in greater detail below. However, it should be noted here that the movable trash intake duct 36 and, more particularly, the depending portion 41 thereof constitute a movable support for the yoke assembly 55, thus rendering the yoke assembly 55 mobile and permitting it to be readily located on either side of the body 13 of the trash collecting apparatus 10 with its associated flexible tubing 43. Thus, the flexible tubing 43 and the yoke assembly 55 may be readily translated from one side to the other of the body 13 of the apparatus 10 without the necessity for extensive rerigging or demounting of the flexible tubing 43 and its associated yoke assembly 55.
Disposed at the opposite sides of the rear portion of the body 13, as best shown in Figs. 1, 2, and 7 of the drawings, are seating structure monting means 64 which include downwardly extending, rigidly braced, longitudinally spaced support arms 66, said support arms being provided with laterally and horizontally extending seat structure receiving sockets 67 which are arranged in vertically spaced pairs on the support arms 66 to receive portions of a seating structure 70 and which facilitate the mounting and demounting of the seating structure 70 on the seating structure mounting means 64 in a manner which will be described in greater detail below.
The seating structure 70 is constituted in part by a supporting frame 72, the supporting frame 72 including supporting members 73 longitudinally spaced from each other and welded or otherwise conventionally secured to the frame 74 of a seat 75. Mounted in the supporting members 73 are extensions 77, the outermost ends of which are receivable in the sockets 67 of the supporting arms 66 of the seat structure mounting means, the seat structure 70 thus being demountable from the sockets 67 in the mounting means 64 to permit the structure to be raised or lowered 'by being mounted in the upper or lower pairs of sockets 67 or to permit it to be moved to the mounting means 64 on the opposite side of the body 13 of the apparatus 10 so that the seat may be disposed in a position wherein the operator of the apparatus may be seated thereupon to control the translation of the lower end of the flexible tubing 43 over a surface which is being cleared of litter or trash. Therefore, the seat structure 70 is movable between upper and lower limits of adjustment so that the height of the seat structure 70 can be conformed to the particular conditions under which the apparatus 10 is operated and also is movable with respect to the mounting 64 so that it can be demounted therefrom and mounted in the mounting 64 on the opposite side of the truck.
Welded or otherwise conventionally secured to the supporting frame 72 of the seat structure 70 is a longitudinally extending tongue 78 adjacent the forward end of which is mounted a footrest 80 upon which the individual controlling the operation of the flexible tubing 43 may rest his feet when he is seated in the seat 75. Fastened between the body 13 of the apparatus 10 and the inner end of the footrest 80 is a cable or chain 82 which serves to maintain the extensions 77 of the seat frame 72 in mounted relationship with the sockets 67 of the seat structure support 64 and to prevent the inadvertent dislodgement of the seat structure 70 therefrom. When it is desired to remove the seat structure 70 from the support 64, the cable 82 is disconnected from the body 13 prior to shifting the seat structure 70 laterally to disengage the extensions 77 from the sockets 67.
In order that the lower end of the flexible tubing 43 may be effectively translated over a surface being cleared of trash and litter so that it may be disposed to pick up particular deposits of trash and litter 45 such as that in Fig. 2 of the drawing, there is provided control means 85 designed to be manipulated by the operator of the apparatus from the seat 75. The control means includes an elongated control arm 87, said control arm having telescoping portions 88 and 89 maintained in operative relationship with each other by pin means 80, the withdrawal of the pin means 90 permitting the tele scoping portion 89 to be pushed into or extended from the outer end of the telescoping portion 88 of the control arm 87.
Provided at the upper end of the control arm 87 is a handle bar 92, said handle bar being engageable by the operator of the apparatus 10 to permit the manipulation of the lower end of the flexible tubing 43 by the control arm 87. Mounted upon the outer end of the tongue 78 is a connecting means 94 which movably secures the control arm 87 to the end of the tongue 78 intermediate the ends of said arm. In the specific embodiment of the invention, the connecting means is exemplified as a ball and socket connection 95, the ball 96 being secured to the tongue 78 and the socket 97 being secured to the underside of the arm 87 intermediate its ends. Of course, it is not intended that the connecting means 94 be limited to any specific type of connection since it is obvious that substitutes for the specific ball and socket connection 95 may be utilized.
Encompassing the periphery of the flexible tubing 43 adjacent its lower end is a control collar 98, said collar being pivotally mounted upon the uppermost ends of vertically extending arms 99 whose lowermost ends are mounted in a nozzle 100 which is suitably affixed to the lowermost end of the flexible tubing 43. The lower end of the control arm 87 is, in turn, fixedly secured to the periphery of the control collar 98 and through the control collar is able to control the movement of the lowermost end of the flexible tubing 43 over a surface to be cleared of litter.
For instance, as the apparatus 10 is drawn along the shoulder or edge of a road or highway or other surface being cleared, the operator of the apparatus 10 may sweep the lower end of the flexible tubing 43 across the surface being cleared by swinging the arm 87 in a horizontal plane. At the same time, the lower end of the tubing 43 can be raised or lowered by appropriate manipulation of the arm 87 in a vertical plane. In this manner, complete control of the lower end of the nozzle 43 is achieved through the utilization of the control means 85 of the apparatus 10.
The body 13, as best shown in Fig. 7 of the drawings, is pivotally mounted on the chassis 12, as at 102, and has operatively secured thereto a hydraulic ram 103 which, when energized, is designed to cause the body 13 to pivot upwardly so that when the doors 105 which constitute the back wall of the body 13 are open, trash and litter collected in the first and second litter collecting compartments and 21 may be easily discharged therefrom. Since the body 13 is pivotally mounted on the chassis 12 in the aforementioned manner and since the power plant 27 is secured to the chassis in conjunction with the blower 29 and its associated housing 30, it is necessary that the duct 24 be separably connected to the housing so that the body 13 may be pivoted on the chassis 12 in the aforementioned manner. To accomplish this end, the duct 24 may be considered as having an intake section107 on one side of the blower 29 and an exhaust section 108 on the other side of the blower. The housing 30 of the blower is provided with an upwardly extending conduit 110 which is designed to seal against the lower end of the intake section 107 of the duct 24 by means of sealing means 112, shown in fragmentary detail in Fig. 4 of the drawings. The sealing means 112 includes an annular flange 114 secured to the upper end of the conduit 110, said flange being'provided with a recess 115 in which is disposed an annular plastic seal 116.
Secured about the circumference of the lowermost end of the intake section 107 of the duct 24 is an annular ring 118 which engages the plastic seal 116 in the recess 115 to prevent the aspiration of air between the juncture of the intake portion 107 of the duct and the conduit 110. The blower housing 30 is also provided with an upwardly extending neck 120 over which the lowermost end of the exhaust section 108 of the duct 24 is adapted to fit (Fig. 5) when the'body 13 is in its normal position upon the chassis 12.
However, when the hydraulic ram 103 is energized to cause the body 13 to pivot upwardly, as best shown in Fig. 7 of the drawings, the intake and exhaust sections 107 and 108 are carried upwardly with the body 13 and are respectively separated from their connections with the conduit 110 and the neck 120 of the housing 30. Of course, the intake section 107, the conduit 110, the housing 30, the neck 120 on the housing, and the exhaust section 108 all constitute a negative pressure passage with communication established between the first and second litter collecting compartments 20 and 21.
During the operation of the trash and litter collecting apparatus 10, it is pulled behind an appropriate towing vehicle by means of the tongue 15 on the chassis 12. Prior to the time when the towing process is initiated, the power plant 27 is started to cause the rotation of the blower 29 in the blower housing 30. During the movement of the apparatus 10 over a surface to be cleared of litter, the operator isseated in the seat and controls the lower end of the flexible tubing 43 by means of the control means 85, manipulating the control arm 87 which constitutes a portion of the control means through the control handle 92 to move the lower end of the flexible tubing 43 in appropriate directions over the surface being cleared of debris.
Of course, if the entire weight of the flexible tubing 43 were imposed upon the operator through the control arm 87, the burden would be unduly tiresome and would result in extreme fatigue to the operator. However, to avoid this contingency, the weight of the flexible tubing 43 is supported, to a large extent by the yoke means 55 which, in its incorporation of the flexible and resilient means 60, adequately supports the major portion of the weight of the flexible tubing 43 but, nevertheless, permits the operator of the apparatus to move the tubing back and forth, laterally, and up and down as the conditions of the surface being cleared of debris necessitate.
As the apparatus 10 is towed across the surface being cleared, the debris is sucked up into the flexible tubing 43 through the movable duct 36, the fixed duct 34, and into the first litter collecting chamber 20 because of the negative pressure imposed upon said chamber by the duct 24 through its connection with the housing 30 of the blower 29 which is driven by the power plant 27 to exhaust the first litter collecting compartment 20 to cause debris to be sucked through the flexible tubing 43 and into the first litter collecting compartment. As the debris and litter are drawn into the first litter collecting compartment, the heavier, bulky, and larger articles, such as large bottles, cans, heavy pieces of scrap metal, etc., drop from the air in which they have been entrained and are segregated in the first litter collecting compartmcnt 20, thus preventing the litter which is of such a size or weight as to cause damage to the blower from being drawn through the duct 24 and into the blower 29. However, the lighter components of the trash and litter entrained in the current of air flowing through the first collecting compartment 20 are sucked through the intake section 107 of the duct 24 and the conduit Iin'to the blower housing 30 whence they are discharged into the neck 120 of the blower housing and the exhaust section 108 of the duct 24 whence these lighter components are discharged into the second litter collecting compartment 21. It should be noted at this juncture that the duct 24 is connected to the first litter collecting comparment from the blower housing 30 by extending through the second litter collecting compartment to the opening 23 in the transverse partition 18.
To prevent the discharge of excessive amounts of fine dust and dirt from the upper, second litter collecting compartment 21, and to prevent the creation of backpressure in the second compartment which would inhibit the deposition of the lighter components of the litter and debris therein, longitudinal, rectangular openings 122 are provided in the side walls of the body 13, but are covered with filter pads 124 which permit the effiux of air from the second litter collecting compartment while, nevertheless, preventing efiiux of excessive amounts of dust and dirt from said compartment.
Therefore, by imposing negative pressure on the first litter collecting compartment 20, the automatic segregation of the heavier components of the trash and litter is accomplished since they are caused to drop out of the air stream prior to the entry of the stream into the blower housing 30. Naturally, the segregation of the heavier components of the litter in this manner accomplishes two extremely desirable ends. In the first place, the possibility that the large, bulky, and heavy components of the litter might be drawn into the blower housing and cause the destruction of the blower 29 is eliminated. In the second place, the heavier and lighter components of the trash are segregated, respectively, in the first and second litter collecting compartments 20 and 21. Therefore, if desired, it is possible to dump the heavier components which are usually incombustible or largely so, in a separate dump from that in which the lighter components are dumped. If this separate dumping is desired, separate doors are provided for one or the other of the first and second litter collecting compartments.
After one edge of a road or highway has been cleared, it may be necessary, particularly in the case of divided highways, to proceed in the same direction to clean the center strip or similar obstruction in the center of the divided highway. To permit the apparatus to function effectively in the clearing of center strips and similar obstructions, the tubing 43 and its associated yoke means 55 are moved and rotated on the movable duct 36 to permit the flexible tubing 43 to depend from the opposite side of the body 13. To accomplish this rotation, the control arm 87 and, more particularly, the socket 97 secured thereto are released from engagement with the ball 96 of the connecting means 94 for permitting the entire assembly to be swung on the movable duct 36 by means of the track and follower wheel 52 to the other side of the body 13.
At the same time, the cable or chain 82 is released from engagement with the body 13 of the apparatus 10 and the seat structure 70 is disengaged from the seat mounting 64 by sliding the extensions 77 out of engagement with the sockets 67. The extensions 77 are then inserted in the opposite ends of the bores 73 and the extensions 77 are then inserted in the sockets 67 in the seat structure support 64 on the other side of the body and the entire apparatus is completely prepared for an additional traverse of the center strip or similar obstruction in the center of the roadway.
We thus provide by our invention a trash and litter collecting apparatus which includes first and second litter segregating compartments which permit the segregation of the heavier from the lighter components of the trash and litter. Furthermore, we provide flexible tubing means for picking up the litter which is supported by a movable yoke suspended from the top of the apparatus,
the flexible tubing being controllable by control means which is accessible from a demountable seat structure mounted on the body of the apparatus. By the use of the apparatus of 'our invention, the economical and thorough disposal of trash, litter, and debris at roadsides, road and highway shoulders, and on other surfaces can be easily and readily accomplished.
We claim as our invention:
1. In a litter collector for collecting and temporarily storing litter, the combination of: a vehicle chassis; a body secured to said chassis; a vertical trash intake conduit extending through the top of said body; a movable trash intake conduit mounted externally of said body in open communication with said vertical trash intake conduit and rotatable in a horizontal plane over said body; circular guide means mounted on the top of said body concentric with said vertical intake conduit; support means mounted on said movable conduit so as to support said conduit upon said guide means; a flexible tubing mounted externally of said body with an upper end communicating with said movable conduit and with a lower end disposable adjacent to a surface to be cleared of litter; a nozzle fixed to said lower end of said tubing; a control arm detachably carried by said chassis on a universal pivot for movement laterally and vertically relative to said chassis; means coupling said nozzle to said control arm adjacent said pivot; handle means mounted on said control arm remote from said pivot for manually moving said control arm and said nozzle laterally and vertically and for partially supporting said nozzle; a yoke collar fixed to said tubing intermediate said ends thereof; collar means fixed to said movable conduit; a pair of resilient elements secured at opposite sides of said tubing between said yoke collar and said collar means for partially supporting said tubing; and suction means carried on said chassis for drawing air through said nozzle of said tubing into said body via said movable conduit and said vertical conduit.
2. In a road cleaning apparatus having a flexible suction tubing with an open upper end adapted to be connected to a source of suction and an open lower end, a construction for governing the movement of said flexible tubing which comprises; a suction nozzle affixed to said lower end of said tubing, an elongated control arm, universal joint fulcrum means removed from said flexible tubing for supporting said control arm intermediate its ends for movement in lateral and vertical directions, handle means on one end of said control arm, said nozzle being pivotally connected to and supported by the opposite end of said control arm for pivotal movement about an axis substantially horizontal and transverse to the axis of elongation of said control arm, and resilient supporting means secured to said flexible tubing intermediate the ends thereof to support at least a part of the weight of said tubing.
References Cited in the file of this patent UNITED STATES PATENTS 796,207 Harbour Aug. 1, 1905 901,490 Sellers Oct. 20, 1908 923,204 Seburn June 1, 1909 943,122 Pollock Dec. 14, 1909 1,159,202 Fish Nov. 2, 1915 1,560,612 Sims Nov. 10, 1925 1,737,855 Kux Dec. 3, 1929 2,184,384 Gregorio Dec. 26, 1939 2,361,909 Bernal Nov. 7, 1944 2,496,028 Wells Jan. 31, 1950 2,502,810 Waters Apr. 4, 1950 2,523,808 Boyce et al. Sept. 26, 1950 FOREIGN PATENTS 486,505 Great Britain June 2, 1936