US2960208A - Concrete paving distributor - Google Patents

Description

NOV. I5, 3.960 1 R SIBLEY ET AL 2,960,208

CONCRETE PAVING DISTRIBUTOR Filed March 5. 1956 5 Sheets-Sheet 1 INVENTORS: JOHN R. SIBLEY MERLE L.HOOVER BYMWI ATTOR N E Nov. l5, 1960 J. R. slBLEY ET AL 2,960,208

CONCRETE PAVING DISTRIBUTOR Filed March 5, 1956 5 Sheets-Sheet 2 l Hull",

IWW` nimm www Q lNvENToRs'l N @vm-' QW z m JOHN R. slaLEY Q3' Q3@ T\\\` lg MERLE I .HoovER Eff: BY Z E e Ll.- LL- \9 l @VWA ATTO RN EY "Y Nov. l5, 1960 Filed March 5, 1956 J. R. SIBLEY ET AL CONCRETE PAVING DISTRIBUTOR Sheets-Sheet 3 "hun mllll 'ummm lllllll' INVENTORS:

JOHN R. SIBLEY MERLE L. HOOVER BYMI'QW,

ATTORNEY Nov. l5, 1960 J. R. SIBLEY ET M CONCRETE PAVING DISTRIBUTOR 5 Sheets-Sheet 4 Filed March 5, 1956 lia N INVENTORSI JOHN R. SIBLEY MERLE L.HOOVER .l I III'I'III'I'III ATTORNEY Nov. 15, 1960 R, slBLEY ETAL 2,960,208

CONCRETE PAVING DISTRIBUTOR Filed March 5, 1956 5 Sheets-Sheet 5 FIG. I6.

INVENTORS2 JOHN R. SIBLEY MERLE L. HOOVER www ATTO R NEY Unite Sttes CONCRETE PAVING DISTRIBUTOR' JohnR. Sibley and Merle L..Hoover,.Franklin, Pa.,A asfl signors, by mesne assignments, to Chain Belt Com-Y pany, Milwaukee, Wis., a corporation of Wisconsin Filed Mar.Y 5, 1956, Ser. No. 569,;463

13- Claims. (Cl 198`73) In known forms of concrete paving distributors. the.

concrete mix is discharged into an elongated hopper, which. extends transversely in advance of the usual strike'. olf plate and with such. an. arrangement thehopper not only frequently clogs. but. also the hopper, to some extent, obstructs the View of the operator. so asV to preventproper observance of the leveling action of the strike oi plate, and further` the Vmix tends to pile up. between the striker 01T plate and the elongated hopper in an objectionable manner. The machine. of the` present inven-A tion contemplates` improvements: over known: types of` pavingV distributors in that the concrete mix is uniformly distributed acrossY the roadbed inf advance of theqstrike oftc` plate.` and that undue clogging-g andy obstruction of view are substantially eliminated..

An object of this invention is. tov providean.` improved road' paving machine having novel features of constructionf whereby the paving operation is substantially expedited. Another object isto provide an improved concrete. paving distributor whereby 4t-he concrete mix is-uniformly distributed to theproper thickness acrossl the roadbed. Yet` another object. is to provide an'improved concrete paving distributor whichis designedf to receive concrete mix directly from a mobile mixer and to convey the mix'- to the distributingV mechanism of the. machine as: the latter advances along the roadbed. A further object` is to'provide'an improvedswingable distributing conveyor having a pivoted discharge chute together with improved means for automaticallyY swinging the chute about its pivot during swinging ofV thev conveyor to cause the chute to-travelalongA a straight path transversely of the machine. A stillV further object is toprovide improved means for avoiding abrupt changes inthe swinging motion of the distributing conveyor. Another. object is to provide improved manual and automatic control means for the' conveyor swinging means. These and other objects and advantagesof the invention will however here inafter more fully appear.

InV the accompanying drawings there is shown for purposes of illustration one form which the invention may assume in practice.

Inthese drawings:

Fig. l is a side elevational viewof a concrete paving machine in which an illustrative form of the-inventionis embodied.

Fig. 2 is a plan View of the paving machineshown in Fig. 1.

Fig; 3 is an enlarged` detail view in. plan showingithe swinging mechanism for the distributing conveyor.

Fig. 4 is atransverse vertical sectionr taken online 4-4-of Fig. 3:, showingT details of one. ofl the swing cylinders;

Fig.- 5 is an. enlarged side view of= a portion. of the `tent controlv mechanism for the conveyor swing cylinders Fig. 6;

Fig. 8 is a fragment-ary side view4 ofthe control lever showing .the lockpin in cross section.

Fig; 9' is an enlarged horizontal section taken on lineY 9 9 of Fig. 13 showing thel trip mechanism.

Fig. l0 is al side viewof the trip mechanism shown in Fig. 9.

Fig. 11 is a detail section taken' on line 11-11 of' Fig. 10.

Fig. l2`is a detail View in plan of the c'ontrol'mecha-l nism shown in Fig. 5.

Fig. 13 is asidev view ofthe control mechanism shownV in Fig. 12.

Fig. 14 isa schematic view in plan showing the'swing@ able distributing conveyor in different` operating. positions..

Fig. 15 is a side view looking in the direction` of. the` arrows of line 15-15 inFig. 1.4 and showingthe swingable discharge chute.

Fig. 16` is an enlarged detail vertical, section. taken online 16,-16 of Fig. 14..

Fig. 17 is an enlargedV detail sectionY takenon. line. 17-17 of Fig. l5.

Fig. l-8- is a diagrammatioview showing thehydraulic fluid system. Y

Fig.4 1.9 is a detail section illustratingA one ofthe check valveand restricted orifice devices.

Theimproved: road paving,y machine, as shown inthe drawings, is generally designated 1 andincludes-aframe 2 mountedonpropelling, andrguiding wheelsy 3 .which travel alongside forms 4f disposed atthe sides. of they roadway to be paved; Mounted on the frame 2 isv aconveyor 5 for receiving the concretemix` or aggregatedischarged from a conventional mobile mixer which travels along one side of the paving machine, and the conveyor 5y discharges onto a distributing or discharge conveyor @which is swivelled at 7- to swing horizontally back and forth as later explained; The conveyorS has an adjustable mounting and may be positioned' about the pivotal axis7 of the conveyor 6Y into an'gularpositionsatk either Side ofI the machine frame, andV a transposable supporting arm 8` is attachable as at 9y to attaching means 10 at either side ofthe machiney frame. conveyors are. desirably. oit' the endless belt. type with the dischargeend` of the receiving conveyor 5v overlying the receiving end of the distributing conveyor 6 and the conveyor belts 11 and 12 are respectively driven by. motors 13 and 14, desirably. of the electric type, through conventional speed reducers. A motor.15,.likewise`de sirably an electric motor, drives throughV a conventional variable speed transmission 16 the propelling and guiding wheels 3 ofthe machine. Operating levers 17 arranged at an operators station 18 on the machine frame are provided for controlling the forward and reverse drives of the transmission whereby the machine may be propelled in either direction.

Fluid cylinder and piston mechanisms 20 serve to swing the distributing conveyor 6 horizontally back and forth on its swivel mounting and the. conveyor frame 21 carriesl wheels 22 which travel along an arcuatev track 23 mounted on the framework. An internal combus tion type engine 24 drives a conventional electric gen.- erator which supplies electric power to the several elece tric motors of the machine, and excess generator capacity may be employed to provide power for other purposes such as electric lighting. Extending transversely across These the front end of the machine frame 2 is a conventional strike olf or spreading plate, or so-called screed 25, for leveling otf the concrete mix to provide a relatively smooth top surface of the roadway and this strike offl plate is adjustable vertically by pivoted arms 26 operated by a hydraulic lift cylinder and piston device 27 (Fig. 18). The screed 25 has vertically yieldable side portions 28 at its respective ends, the lower edges of which extend below the tops of the side forms 4 close to the inner sides of the latter. The side portions 28 are each constituted by a plate slidably mounted for vertical movement and provided with an out-turned forward edge notched to rest upon the top of the side form and serving to clear it of spilled concrete. Tension springs are connected to upstanding members on each side plate 28 in a manner to hold the plates down upon the tops of the side-forms while permitting yielding movement thereof to accommodate irregularities in the forms.

The swingable distributing conveyor 6 discharges into a`chute 30 which is suspended from the outer end of the conveyor frame and this chute is pivoted at 31 to rock back and forth so that as the conveyor is swung horizontally the bottom discharge end 32 of the chute follows a substantially straight path across the machine in advance of and in substantial parallelism with the screed plate 25.

The means for automatically swinging the discharge chute as the distributing conveyor 6 swings horizontally comprises an arcuate cam member 33 secured to the framework and having its opposed cam surfaces engaged by rollers 34 and 35 as shown in Fig. 14. The rollers 34 and 35 are carried by the inner arm 36 of a yokeshaped frame 37, the side yoke arms 38 of which are pivotally connected Aat 39,to the sides of the discharge chute. Thus as the distributing conveyor 6 is swung horizontally the discharge chute, through the cam and rollers, Swings back and forth about its pivot between the full and dotted line positions shown in Fig. 15.

Now referring to Figs. 3 and 4 showing the detail l structure of the swinging mechanism 20 for the distributing conveyor 6, it will be noted that arranged transversely of the machine frame and underlying the swingable distributing conveyor are parallel stationary horithe swing cylinders and pistons. The operating rod 66 at its left-hand end, as viewed in Figs. and 13, carries a pin 67 alternately engageable with spaced fingers 68 on a tripper lever 69. This tripper lever is secured to a horizontal shaft 70 journaled within a bracket 71 mounted on the framework. Also secured to the shaft 70 is a lever 72 engageable with spaced abutment pins 73 to v constitute a lost motion mechanism. The abutment pins zontal Huid cylinders 41 and 42 suitably secured to the y framework and respectively containing reciprocable pistons 43 having oppositely extending piston rods 44 and 45. These piston rods at their remote ends carry brackets 46 which have rollers 47 journaled thereon and these rollers travel in longitudinal guideways 48 provided by parallel guide members 49 on the framework. Carried by the piston rod brackets 46 are double sheaves 50. Journaled on brackets 51 on the framework at the remote ends of the fluid cylinders 41 and 42 are double sheaves 52. A pair of cables 53 and 54 are each attached at one end at 55 to the under side of the conveyor frame 21 and extend in opposite directions around guide sheaves 56 and 57, and are reeved about the sets of double sheaves 50 and 52, and the opposite ends of the cables are attached at 58 to adjustable connections 59 on the framework. Thus as pressure fluid is alternately supplied to the fluid cylinders 41 and 42, each of the cables 53 and 54 in turn is placed under tension while the other is slackened to effect swinging of the conveyor frame back and forth on its swiveled mounting. Evidently, the f ments 63 which engage with dogs 64 and 65 secured to the opposite end portions of a shiftable operating rod 66 suitably guided on the framework in parallelism with 73 with which the lever 72 is alternately engageable are secured to a swingable arm 74 pivotally mounted at 75 ony the hub of the lever 72 (Fig. 11) and this arm has a lateral lever portion 76 pivotally connected at 77 to a vertical operating rod 78. As shown in Fig. 13, this rod 78 carries at its upper end a pin 79 which is movable vertically in a slot 80 ofV a compound lever 81. The lever 81 is pivotally mounted at 82 on the framework and the slot 80 is in a slidable portion having a longitudinal opening within which the lever is in the .form of a vertical plate 83 having a slot 84 which is similar to and in Fig. 6 is shown in registry with the slot 80. The slot 84 has a lateral notch 85 for receiving the pin 79, when it is desired that the operating rod 78 effects swinging of the lever 81. A spring 86 urges the slidable part of thelever 81 relative to the plate 83 in direction to hold the pin 79 in the notch 85, and a handle 87 on the lever 81 is provided for manually swinging the lever. A

cooperating lever 88 is pivotally mounted on the lever 81 and is pivotally connected to the slidable part so that it may be shifted forwardly against the action of the spring to release the notch from the pin 79 so that the latter may move with the operating rod 78 freely back and forth relative to the lever 81 within the slot 80 without motion of the lever 81. The operator may grasp the handle 87 to swing the lever 81 when manual shifting is desired. The` lever 81 is pivotally connected at 90 to the valve stem of a control valve device as later described.

As shown diagrammatically in Fig. 18, a conventional uid pump 91 suitably driven by the engine 24 has its suction side connected by a conduit 92 to a tank 93 for containingrfluid, desirably a liquid, and the discharge side of the pump is connected by a conduit 94 to the control valve device which is designated 95. A return conduit 96 connects the discharge passage of the valve device back to the tank. v The valve device has a casing 97 secured to the framework and provided with bores for receiving ' shiftable control valves 98 and 99, desirably of the balanced spool type each having an operating stem. The bore containing the valve 98 is connected by conduits and 101 to the remote ends of the fluid cylinders 41V and 42 while the bore containing the valve 99 is connected by conduits 102 and 103 to the opposite ends of the screed lift cylinder 27. The stem for the valve 99 has a usual operating handle while the stem ,for the valve 98 is pivotally connected at 90 to the operating lever 81.

Associated with the uid conduits 100 and 101 are combined check valve and restrictor devices 104 and conventional relief valves 105, which cooperate with the inherently flexible cables 53 and 54 to provide a relatively smooth cushioned reversal in movement of the swingable conveyor, thereby to reduce the throwing of the cement mix laterally with substantial force toward the side forms 4. Each of the devices 104, as shown in Fig. 19, comprises a casing 106 having a passage 107 extending between branches of either o-f the conduits 100 or 101 and containing a check valve 108. A bypass passage 109 communicates with the passage 107 at opposite sides of the check valve and contains an adjustable valve 110 which provides a restricted orifice. The relief valves 105 are connected in conduits 111 and 112 4which lead from Athe conduits 100 and 101 back to the tank 93. The pressure uid flows from the valve 98 past the check valve 108 alternately to the fluid cylinders 41 and 42 depending upon the direction of swing o f the conveyor and when the pistons are retracted fluid is forced from thecylindersI through the restricted orifices provided by the valvesV 110, with theV check. valves 108 held closed. Thus a cushioned reversing movement'of the conveyor is effected by reliefy valve action, by taking advantage of the elasticityy ofthe cables, and byslocating the cable connections at an advantageouspoint on-.the conveyor while cable tension` under Varying conditions' is'. maintained by adjustably restrictinguid flow.. Also the manual control 87,. 88. asso'ciateduwithi the-automatic control for the reversing valve makes for: readyfregulae. tionof the swinging movem'ents off'the conveyo-r, sub'- stantiallyA increasing theV overall? operating. efficiency of themachine.

When the` lever 81 is. in automatic. controlI position with t-hepin 79 in the notch 851th`e'vcontrol valve'- 981 is automatically shifted at the endz of. thepiston strokes of the swingY cylinders so. thatitheY distributing conveyor 6 is repeatedlyswung back and forthonitsswivel mount, ing during the distributing. operation. 'When it. is desired manually to shift the valve 98 Athe. lever 88 may' be grasped by the operator'to move: the slidablepartzofr the lever 81 andthe slot 80: relative tothe' notch 85 tov free the pin 79 therefrom, and at that time the pin 79 may reciprocate freely in thev slot 80 while the lever 81 remains relatively stationary. The lever 81' may then be swung manually to shift the control valve 98 to regulate the ow of fluid to the swing cyhnders, as desired.

A control panel 115 is arranged on the framework at the operators station 18 ('Fig. 1) and contro-l devices 116, 117 and 118 are provided where the operator may control the several motors and the speed of the engine, as desired. As previously mentioned, the. drive of the propelling wheels and the transmission speed and the direction of wheel-drivemay also be controlled from the operators station.

As a result. of thisv invention an improved road paving machine is provided having improved distributing means for the concrete mix whereby the mix is distributed in uniform depth across the roadbed. By the provision of the automatic swinging means rapidly swinging the distributing conveyor back and forth together with the swingable ydischarge chute, mix is delivered to the roadbed without undue splashing and in uniform amounts across the machine in advance of the leveling screed. By the provision of the hydraulic swing cylinders, the cable connections, the associated arrangementof the relief valves and restrictors, and the advantageous manner of connection of the cables with the conveyor, relatively smooth swinging of the distributing conveyor is obtained therebyv substantially eliminating abrupt changes in direction of. the conveyor at the ends of the swinging strokes and as a result avoiding undesirable thro-wing of the cement mix laterally in the Idirection of conveyor swing and minimizing side reaction forces against the side forms due to reversal in the swinging motion of the conveyor. The manual control feature, in cooperation with the automatic reversing valve control, improves the distributing function by enabling improved regulation of the conveyor movements. The wide range of variable speeds for the machine propelling wheels pro-vides for further improved machine-operation by insuring uniform deposition of material at any desired depth, width or rate of feed. The improved distributing conveyor and its pivoted discharge chute, together with the automatic swinging means for the discharge chute coordinated with the swinging motion of the conveyor, provide for the even distribution of the concrete mix across the roadway instead of the usual dumping of batches which require considerable spreading. The arrangement of the distributing means not only leaves the view of the 'screed relatively unobstructed but also eliminates undue clogging which frequently occurs in machines of the hopper spreader type. Other advantages of the invention will be clearly apparent to those skilled in the art.

While there is `in the foregoing specifically described one fo-rm which the invention' may assume in practice; it'. will'l be: understood that"` this. form of the same isishowrr forY purposes. of illustration and that' the invention may be. modified and. embodied in various; other forms: without departing from its spirit or the scope of the appended claims.

What we: claimfasnew-anddesire to secure by'Letters Patent; is:.

1;.Imamoadpavingmachine, a mobileV base movable overA zu. roadbed toV- he pavedg.. av conveyorl pivotally mounted on said basev to.` swing 'rapidly/'back andl. forth about' an upright axis,. a pivoted. discharge` chutel suspended. from'. the' outer discharge end of said-A conveyor` tol 'swingt backf and: forth; about: av horizontal axis,` and meanszf'or coordinating' theswinging movement of said chutewith; said: conveyor swing whereby the bottom dischargesendol': saidvl chute traverses a substantially straight path.

2l.. Inr ai road'paving'- machine, a. mobile base movable over a roadbed to be paved; a distributing conveyor swingable horizontally back and forth from one side' of the roadbed to; thei other, means for automatically swinging said conveyor, a-discharge chute pivotally'suspended from the end: ofsai'd conveyor.' in amanner to be swingable in the vertical plane of said conveyor, camv means onl said; base; and' chute swinging. means engaging said camL means whereby'thez discharge end of said chute is caused to swing in azmanner to traverse a straight path across the roadbed asl said' conveyor is swung back and, forth;

3. A roadf pavingmachine: having amobile base movable: along^ forms at the sidesof a roadbed to be paved with concrete mix, saidbase extending.transverselyof the roadbed between the; side forms,.conveying means movably mounted` on saidbase for'receiving, conveying and discharging: the. concrete' mix; means; for uniformly discharging: the. mix received` from said conveying means along the roadbed close to the latter and in advance of said? base including a depending'discharge means pivotally' attachedtothe outer discharge end of said movably mounted conveying means, meansfor swinging the outer discharge end of said movably mounted conveying means back` and forth. transverselyof the roadbed, and means engaging' saidl pivotally attached depending discharge means' as*V it moves rapidly back and forth to swing it along a'. straight path in parallelism with said base and transversely of the roadbed as said base advances along the'forms. i

4;v Ai. road paving machine: as set forth in claim 3 wherein: said depending discharge means is pivotally suspended at thef outer discharge end of said conveying means, and saidl swinging means provided for swinging .said suspended discharge-means aboutA its pivot includes a cam member shaped to` causesaid discharge means to traverse said straight path.

5. A road paving machine asset forth in claim 4 wherein said conveying means hasy a horizontally swingable discharge portion from which said discharge means is pivotally suspended and saidv swinging means for said discharge means is coordinated with the swinging motion of said swingable discharge portion of said conveying means.

6. A road paving machine as set forth in claim 5 wherein said swingable discharge means is in the form of a substantially upright discharge chute having its biottom discharge opening close to the roadbed.

7. A road paving machine comprising a mobile base, a horizontally swingable distributing conveyor pivotally mounted on said base to swing relative thereto, iluid operated cylinder and piston devices operatively connected to swing said conveyor back and forth about its pivot, automatic valve means responsive to the swinging motion of said conveyor for reversing the direction of swing, reversing control means actuated at the end of each swinging stroke, and manual control means operatively associated with said reversing control means and said automatic valve means and operative selectively to connect said reversing control means for automatic control of said automatic valve means or to actuate said valve means at will thereby to provide for manual regulation of cnveyor swing.

8. A road paving machine as set forth in clainil wherein said automatic valve control includes a rocking control member and said manual control includes manual means operable at will for interrupting rocking movement of said control member by its automatic means.'

9.'Ina machine for distributing plastic concrete in paving roadways and the like, a machine framearranged for movement along a roadway 'strip being paved, said frame being in position to extend transversely of the strip being paved and arranged to move over the surface of a layer of plastic concrete deposited ahead of it, a conveyor for concrete pivotally mounted atits receiving end on said frame with its discharging end projecting ahead of said frame and arranged for swinging movement from side to side of the strip being paved, a placing chute pivotally suspended from said discharging end of said swinging conveyor in position to guide the plastic concrete descending from said conveyor onto the roadway strip, power actuated means arranged to swing said conveyor back and forth across the roadway, and guiding means on said frame operative to guide the transverse movement of said pivotally suspended placing chute in a manner to cause its lower end to follow a substantially straight line path across the roadway strip in advance of said frame, whereby plastic concrete from said conveyor may be deposited evenly in' successive ribbons ahead of said trame to form a layer of pavement as said machine progresses along the roadway strip.

10. The combination as set forth in claim 9 wherein said straight line distribution guiding means includes a `cam carried by said frame and a cooperating follower operatively connected to said pivotally suspended placing chute.

11. In a machine for distributing plastic concrete in lpaving roadways and the like', a machine frame arranged for movement along a roadway strip being paved, said frame being in position to extend transversely of the strip being paved and arranged to pass over a layer of plastic concrete deposited ahead of it, a conveyor for concrete pivotally mountedat itsreceiving end on said frame with its discharging end projecting ahead of said frame and arranged for swinging movement from side to side of the strip being paved, a placing chute pivotally suspended from said discharging end of said swinging conveyor and arranged for pivoting movement to guide the plastic concrete descending from said conveyor onto the roadway strip, means arranged to swing said conveyor back and forth across the roadway to distribute the concrete, and guiding means on said frame operative to pivot said pivotally suspended placing chute in conjunction with its 'transverse swinging movement in a manner to cause its lower end to follow a substantially straight line path across the roadway strip in advance 'of and parallel with said frame, whereby plastic concrete from said conveyor 8 may be deposited evenly in successive ribbons ahead of said frame to form a layer of pavement as said machine progresses along the roadway strip.

12. In a machine for distributing plastic concrete in paving roadways and the like, a machine framearranged forfmovement along a roadway strip being paved, a conveyorfor plastic concrete pivotally mounted at its receivingfend on a vertical axis on said frame with its discharging end projecting over and arranged for swinging movement from side to side of the roadway strip being paved, a placing chute pivotally suspended from said projecting discharging .end of said swinging conveyor in position to receive and guide plastic concrete descending from said conveyor onto the'roadway strip, power actuated means arranged to swing said conveyor to traverse said placing chute back and forth across the roadway strip,l and guiding means on said frame operative to guide the'traversing movement of said pivotally suspended placing chute in a manner to cause its lower end to .follow a substantially straight line path across the roadway strip, whereby plastic concrete from said conveyor may be deposited in successive transverse ribbons of pavement as said machine progresses' along the roadway strip being paved.

13. A road paving machine comprising a mobile base movable along a roadbed being paved, a distributing conveyor pivotally mounted on said base for horizontal swinging movement about a vertical axis with `its outer discharge end traversing back and forth from side to side of the roadbed, a discharge chute pivotally suspended from said swinging outer discharge end of said conveyor for swinging movement in a vertical plane extending radially from said vertical pivot axis, and means coordinating the swinging movement of said discharge chute .with tihe swinging movement of said conveyor in a manner to cause the lower discharge end of said chute to traverse a substantially straight path across the roadbed.

References Cited in the file of this patent UNITED STATES PATENTS 721,215 Metzger Feb. 24, 1903 968,053 Heldmann Aug. 23, 1910 1,582,468 Heald et al. Apr. 27, 1926 1,613,051 Napier Jan. 4, 1927 1,717,734 Robb June 18, 1929 1,755,653 Koehring Apr. 22, 1930 1,847,433 Krause Mar. 1, 1932 2,021,767 Church Nov. 19, 1935 2,034,942 Dodds Mar. 24, 1936 2,269,781 Osgood Jan. 13, 1942 2,295,519 Millikin et a1 Sept. 8, 1942 2,563,432 Sterler Aug. 7, 1951 2,583,108 Lewis Jan. 22, 1952 2,649,185 Lichtenberg Aug. 18, 1953 2,848,100 Jasper Aug. 19, 1958 FOREIGN PATENTS 148,877 Australia Nov. 4, 1952

Images