US2491797A

US2491797A - Side grading attachment for tractors and the like

Info

Publication number: US2491797A
Application number: US640240A
Authority: US
Inventors: Murray E Burns; George M Bonnell
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-01-10
Filing date: 1946-01-10
Publication date: 1949-12-20
Anticipated expiration: 1966-12-20

Description

., 9 W49 IM. E. BURNS mm 294919797 SIDE GRADING ATTAQHMENT FOR "TRACTORS AND THE LIKE Filed Jan. 10, 1946 s Shets-Sheet z.

SIDE GRADING ATTACHMENT FOR v".RAGTORS AND THE LIKE M. E. BURNS ET AL 5 Sheets-Sheet 2 Filed ,Jan. 10, 1946 H 7 fie M e SIDE GRADING ATTACHMENT FOR TRACTORS .ANDTHE LIKEJ Filed Jan. 10, 1946' I L A s N R u B E M 5 Sheets-Sheet 3 Ina/Mm. e 21.302212 ei Wm m W49 M. E. EURNS ETAL SIDE GRADING ATTACHMENT FOR TRACTORS AND THE LIKE Filed Jan. 10, 1946 5 Sheets-Sheet 4 M. E. BURNS ET AL Dec. 2@, 1949 SIDE GRADING ATTACHMENT FOR TRACTCRS AND THE LIKE 5 Sheets-Sheet 5 Filed Jan. 10, 1946 n 'lIVIIIlIdlIl-IAI III! 5 Midi? m&

Patented Dec. 20, 1949 lTED SIDE GRADING ATTACHMENT FOR TRACTORS AND THE HIKE Murray E. Burns and George M. Bonnell, Boise, Idaho 9 Claims.

This invention relates to side grading attachments adapted to be mounted on conventional tractors and utilized for purposes such as the grading of ballast and the road bed shoulders along the sides of a railroad track.

It is a general object of our present invention to provide an improved grading attachment adapted to be secured to and operated at the side of a tractor or the like and which is adjustable in various ways to suit the purposes and conditions of use.

Another object of this invention is to provide a grading attachment for tractors and the like which normally extends outwardly at one side of the tractor during use, but which may be easily and quickly swung upwardly and inwardly to an out-of-the-Way position in moving from place to place or to avoid obstacles.

I'he invention has for a further object the provision of a side grading attachment which may be readily attached to and detached from a standard tractor.

Considered more specifically, it is an object of our invention to provide an attachment for tractors particularly suited and adjustable to the grading of ballast and the road bed shoulder along a railroad track as the tractor runs on the rails.

As another object the invention contemplates the provision or a grading blade including adjustable auxiliary ballast and shoulder sloping parts and an attached wing tending to prevent the of ballast material.

The obccts of the invention also comprehend the provision of an improved adjustable support for a grading blade adapted to be utilized on tractors and the like.

Other objects and advantages will be apparent from the following description and the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views.

Referring to the drawings, of which there are five sheets,

1 is a side elevational view of a preferred form of our side grading attachment shown in its mounted position on a standard tractor and indicates its adaptation to the grading of ballast and the road bed shoulder along the sides of a railroad track;

Figs. 2 and 3 are respectively top plan and front elevational views of the mounted grading attachment shown in Fig. 1 and illustrating the same adaptation;

Figs. 4 and 5 are respectively top plan and front elevational views of our preferred grading attachment drawn to a larger scale than that used in Figs. 1, 2 and 3, and having the tractor and associated support parts indicated by dotand-dash lines;

6 is an elevational view looking directly one face of the preferred form of our grading blade shown from different positions in Figs. 1 to 5 inclusive;

Fig. '7 is a fragmentary sectional view with the section taken substantially on a line 'l--'l of Fig. a; and in the direction indicated by the arrows;

Fig. 8 a fragmentary sectional view with the section taken substantially on a line 3-B of Fig. 'l and viewed in the direction indicated by the arrows;

Figs. 9 and 10 are fragmentary sectional views with the sections taken substantially on lines 9-9 and ill-413 of Fig. 5 and viewed as indicated by the arrows; and

11 is a sectional view with the section taken substantially on a line li-ll of Fig. 7.

In Figs. 1, 2 and 3 the preferred embodiment of our invention is illustrated in its adaptation to the grading of ballast and a road bed shoulder along the side of a railroad track wherein the road bed has a shoulder i5 and carries a top layer of ballast it which generally consists of rock, gravel or cinders and surrounds the lower side and end surfaces of ties ll to which rails 58 are secured.

It is desirable that the ballast shall closely surround the lower surfaces of the ties and be sloped upwardly toward the tops of the ties along the sides to form a firm and substantial footing for the tracks. Beyond the edge of the ballast the road beds generally have a fiat surface and a shoulder edge which may slope upwardly or downwardly, depending upon the profile of the terrain through which the track is built.

Although the disclosed side grading attachment may be attached to various standard types and makes of tractors, it is disclosed in this instance in Figs. 1, 2 and 3 in its application to a tractor E9 of the track laying or crawling type which is desirably equipped with a double winch 20 mounted at the rear of the tractor and operated from the tractor engine. For convenience in operation on a railroad track, the treads of both endless tracks 22 are equipped with flanged track walking feet 23 such as those illustrated and described in our issued United States Patent No. 2,322,919. When normally running along the rails of a railroad track, as shown in Figs. 1, 2 and 3, the flanges on the track walking feet 23 6 run inside of the rails and cause the tractor to follow the track without use of the steering mechanism.

Along each side, the tractor l9 has a frame member 2% to which outwardly projecting studs are secured. The studs 275 rotatably support the ends'of a yoke 2* for vertical swinging movement. The yoke 28 has side arms 21 which extend along the opposite sides of the tractor outside of th frame members 26 and tracks 22. It also includes an integral connecting portion 28 which extends across the front of the tractor in spaced relation thereto. H

In addition to the yoke 26, an overhead support frame 29 is mounted on the tractor and includes support spars 3t and 32 and a longitudinally extending top beam 33. On each side of thetractor the support spars 3B and 362 have their lower ends secured to support brackets 3% which are in turn secured to'the side frame structure of the tractor. flhe rear support spars 35 extend upwardly and to the rear and are curved inwardly 'over the tractor with their upper ends secured to opposite sides of one end of the top beam 33. The front s pport spars 'fifexterid'upwardly and forwardly from the brackets and are curved inwardly andsecured to a lateral frame member 35. A cross bracete is desirably secured to the support spars "3'2 iiiterrriediatetheir ends. At the forward end the top'beam 33 1s secured to the lateral frame inembelfcfi 'through'fastening means such as brackets 3? is supported thereby.

I 'Desirably the "topb'e'am 33 is tubular and acts "as a cable'conduit'as well as serving as a part oi the upper support frame. Sheaves 3d and 39 are roteltably supported "in housings and =32, respectively, at each end of the top'beam 33. A cable hasanehd it anchored to the top beam structure and extends around'a pulley &5, over tlie slie'ave'sdd and 39, through the top beam 33 and thence downwardly at the rear of the tractor tonne windihgjdrum tear the winch "2B. The pulley-i 'isrotatably secured to the mid portion of the front of the yoke 23 through a bracket structure 3'! there n. ihus, operation of the u n thewinch, the'yoke 26 may be swung H ardlyordownwardly. When the'drum 36 is stationary the'yoke 25 is supported at a predeterinined level by the cable.

I In order to provide additional support for the fy'ol're part larly in a use such as that to "which the gr ding attachment is adapted in the present disclosure, "flanged rollers d8 are rotatf'ably supported and secured to the lower surface of the yoke 23b3 smaller downwardly projecting 'yokes' ld. In the presentadaptation, the flanges are provided on the'ihner edges of the rollers "and theyare space'd'to suit the gauge of the railroad track on which'the'tractor is operated so that the flanges run along the inner surfaces of the rails and assist in the guiding of the tractor. The mounting of the rollers is illustrated in Fig. 5; onset the roller'yokes l9 being broken away in Fig. 3 better to illustrate the track walls ing feet 23cm the'tractor treads. I I Alinearly adjustable horizontal support 55, the "internal structure of fwh'ichis illustrated in Figs. fl andfS, has a h'ousing '52 made up of a base plate 53, oppositely disposed and spaced side plates 5Q having their edges secured to the base plate 5? as by welding at lififahd a cover plate 55 removahly secured tothe upperilanged edges f 'thesidapl'atesI'E l bymeans such as series of bolts 51. Within the housing the horizontal support slide 53 which is desirably of I-beam plate at one ed and having a removable cover 6'? at the other end.

. Although various types of mechanisms might housed for dete .ing the position of the horizontal support slide 58 within the housing 52, the disclosed. embodiment includes an adjusting mechanism E38 enclosed within'the auxiliary'housing and adaptedto be manually operated by a crank 69 supported on the tractor structure as shown in and secured to a shaft ill. i'he disclosed adjusting mechanism has'a shaft journaled in a bearing '53 which 1s carried by a b o-c1 on one side of the housing '53 which sn it hasdrivingly connected to its inner end a bevel gear '5 Meshing with the bevelgea-r i5 is a second bevel gear '58 drivingly mounted upon a sleeve "ll which is rotatably carried a bearing A collar l9 welded to the inner su*ace oi the end closing plate 66 carries the bear 78. At the opposite end of the auxiliary housing es the removable cover 6? has threaded into a central opening 35 therein and in alignment with the axis of'the bearing 18, a cylindrical and adjustable housing extension 82 the outer end of which is closed. At its inner ;end the'housihg extension carries a bearing 33 which rotatably supports a sleeve 8% the inner end of which abuts the sleeve ll. The bearin s 78" and 83 are adapted to absorb axial thrust in opposite directions.

A screw 85 extends through aligned central openings 2'36 an in the plates 62 and 65 respectively'and is threaded into the collar ii so that rotation of the shaft i?! by manual operation of-the crank ii turnsthebevelgears 72 and 16 and the sleeve ll to vary the position of the screw 85. Within the hcusing'lii the end of ;,the screw 35 is connected to the support slide 58 by links 85, which links are secured to the slide Stand screwfib'by pluses and 9G extendung-therethrough. Thus the horizontal position of the support 'slidedfi' is determined from a convenient place on the tractor structure by turnin the crank 69. a

Rigidly'secured tothe end of the support slide 58 wh ch extends from the housing 52 is a vertical "cross beam "Cylin'dricalsli'de bearings 93 and M are secured in axial alignment and in spaced "relation'to t e side'of the cross beam 92 opposite the support slide 58. An adjustable vertical slide Sill journaled in the bearings 93 :andihifor bothrotary and axial sliding movement. For etermining' the adjusted axial posi tion' of the slide-95, a suitable manually operable adjusting mechanism is provided and enclosed Within a housing at one end of the bearing 93. 'Inthe disclosed embodiment, thehousing 5? includes a cylindrical side wall welded to an end plate% and provided with a removable cover lilt. The end plate 99 has in'its outer *surraceen annular recess E92 which fits over the 75 end of the bearing $3. As illustrated in Fig. 11,

5 the housing 9'! is secured to the end of the bearing 93 by screws 403 which extend through lugs Hi l on the outer surface of the bearing and are threaded into the projecting side portion of the end plate 953.

As illustrated in Figs. 7 and 9 and like the adjusting mechanism $3 for determining the position of the support slide 53, the adjusting mechanism 96 includes meshing bevel gears I95 and I06, manually operable by turning the crank Ifil Secured to a shaft lint and mounted at a convenient position on the tractor structure. A shaft I03 carries at its inner end the bevel gear 106 which is keyed thereto, and is journaled in a bearing llil supported in a block II2 on the side of the housing wall fill. The co-acting bevel gear I95 is keyed to a sleeve H3, which sleeve is rotatably supported by a bearing Ii l carried adjacent the lower end plate 99 by a ring i 55. The sleeve IE3 is retained axially at the end opposite the bearing H l by a sleeve IE6 secured to the removable end Hit of the housing. A screw Ill is threaded into the sleeve H3 and has one end connected to cross plates ME in the end of the slide 55 by a pin H9. Rotation of the crank ill! turns the shaft lilll axially to adjust the position of the slide illi relative to the end of the support slide 58. A hinge plate 52%; (Figs. l, 5 and '7) desirably comprises a pair of reenforced and parallel side plates E22 projecting from the mid portion of one side of the slide 25 in spaced relation relative to one another.

Connecting elements such as brackets 523 are secured to the lower surface of the base plate 53 and are adapted to be removably secured to the connecting portion 23 of the yoke 26 by fastening means such as bolts IM to support the housing 52 transversely of and adjacent the front end of the tractor. With the horizontal support slide thus mounted at the front end of the tractor and having at one end the vertical slide 95 carrying the hinge plate I20, it may be understood that the hinge plate provides an adjustable supporting element at the front and to one side of the tractor. In addition to being swingable about the axis of the vertical slide 95, the position of the hinge plate E28 may be adjusted to various fixed positions vertically and horizontally by manual operation of the cranks 69 and Illl.

A main grading blade lZE which is desirably reenforced on one side by a channel strip I26 has one end disposed between the parallel side plates it? of the hinge plate E29 and rotatably secured therebetween by fastening means such as a bolt ml. The end surface of the main blade I25 is curved in concentric relation to the bolt It? to permit the vertical swinging movement of the blade about the axis of that bolt. In order to hold the main blade in any one of a plurality of fixed positions relative to the hinge plate I29, a series of openings I28 (Fig. 6) are concentrically disposed in spaced relation relative to the axis of the bolt Hi to accommodate a pin I28 received in suitable aligned apertures in the hinged plate and extending through a pre-selected one of the openings I28. In order to avoid loss of the pin 25, it may be connected to the hinge plate I28 by flexible means such as a chain I30. While the drawings illustrate only one hole in the main grading blade M5 for the accommodation of the bolt IE'I and one set of concentrically disposed holes I28 for receiving the pin I29, it is understood that the possible range of vertical positions to which the blade may be set may be increased by the addition of one or more sets of similarly disposed openings vertically displaced from those shown.

The lower edge of the main grading blade lie has angularly disposed portions I32 and 533 as indicated in Fig. 6. Secured to the blade adjacent the edge portion 32, is a hardened plate It l which projects beyond the edge I32 to provide a grading edge adapted to withstand wear. The grading edge provided by the plate l3l is desirably at the outer end of the main blade remote from the hinge support provided by the hinge plate lilll. The angularly disposed inner edge portion I33 which extends inwardly from the edge E32 slopes upwardly toward the hinge plate.

An auxiliary ballast sloping blade I35 has a hardened grading edge provided by a plate I36 secured thereto and is rotatably connected at one end to the main blade near the inner end of the edge portion I32 by means such as a bolt E31. Outer end portions E38 and IE8 of the auxiliary ballast sloping blade and the plate L36 are preferably curved in concentric relationship to the axis of the bolt I37 and at a distance therefrom which effects alignment of the grading edges of the plates I34 and I36. Near the inner end of the auxiliary ballast sloping blade, a series of spaced apertures I39 is disposed in concentric relationship with respect to the axis of the bolt I3! and adapted to receive fastening means such as bolts Hill for securing the auxiliary ballast slopin blade in the desired angular position relative to the grading edge provided by the hardened plate I3 5. With the main blade adjusted to a desired angular position and to a desired hei th, the angular position of the auxiliary ballast sloping blade determines the slope of th ballast upwardly toward the ends of the ties. It may also be understood that for preliminary or other grading operations. the position of the auxiliary blade may be adjusted to other angles relative to the main blade or may be set to a position in which the grading edges of the main and auxiliary blades are in alignment, as indicated in dot-and-dash lines at I350 in Fig. 6.

In order to provide for the movement of a supply of ballast material in front of the blade for filling in depressions and also to prevent the loss of ballast material by spreading it at the outer edge of the grading blade, a wing plate Hi2 has one edge bolted to the main blade near the outer end of the auxiliary ballast sloping blade and projects outwardly at an angle from the front surface of the main blade. As shown. in Figs. 4 and 6, braces I43 desirably are provided to extend from the outer or projecting end of the wing plate to the surface of the main blade to rigidify the wing plate. As shown in Fig. 6, it is also desirable that series of spaced openings IM and I45 are provided in the mounting edge Hit of the wing plate and an anchor bracket I I! secured to the inner ends of the braces its to permit adjustment of the position of the wing plate relative to the main blade. Since the function of the wing plate is to retain a supply of ballast in front of the main blade and prevent waste of the ballast by spreading, rather than that of performing the grading function of the main and auxiliary blades, it is considered preferable that the Wing plate should. be set at a position somewhat above the grading edge of the main blade, and that its position should be demember linearly adjustable laterally of the tractor, a vertical support secured to said member at one side thereof and including a rotatably supported member adjustable vertically of the tractor, an overhead frame adapted to be secured to the tractor, a main blade hingedly connected at one end to the rotatably supported and vertically adjustable member for swinging movement about the horizontal and vertical axes of the hinge connection and rotatable support, said main blade normally extending outwardly from the vertically adjustable member and being angularly disposed rearwardly with respect to the horizontally adjustable member, a substantially rigid blade brace having one end hingedly connectedlto the main blade and its other end adapted to be hingedly anchored to the tractor at a distance from the horizontal and vertical supports, adjustable cable means supporting the main blade from the overhead frame, a wing plate extendd ing outwardly at an angle to the surface of the main blade on the side thereof opposite the blade brace and near the end of the main blade away from the hinge support therefor, an auxiliary blade mounted against the face of the main blade and adjustable to various angular positions relative to the horizontal to define the slope of a portion of the scraping edge of the main blade, and a second auxiliary blade extending from the end of the main blade and adjustable to various angular positions relative to the horizontal to provide a variable extended scraping edge on the main blade.

2. A side grading attachment ior tractors and the like comprising, in combination, main support means adapted to be secured to the tractor and including horizontally and vertically adjustable members, said vertically adjustable member also being rotatable about a vertical axis relative to the horizontally adjustable member and having a connecting plate carried thereby at one side of the support means, auxiliary support means also adapted to be secured to the tractor, a main blade hingedly connected at one end to the connecting plate for swinging movement relative thereto and substantially in the plane thereof, said main blade normally extending outwardly at an angle away from the support means and along one side thereof, a substantially rigid blade brace having one end hingedly connected to the outwardly extending end portion of the main blade and its other end adapted to be hingedly anchored to the tractor, adjustable means supporting the main blade from said auxiliary support means, a wing plate extending outwardly at an angle from the face of the main blade cpposite the blade brace and near the end of the main blade, and an auxiliary scraper blade secured to the main blade and adjustable to positions relative thereto for varying the slope of a portion of one edge of the main blade.

3. A road bed and ballast grading attachment for tractors and the like which are adapted to run along the rails of a railroad track during the grading of the ballast and road bed outside of the ties which support the rails and comprising, in combination, a support yoke adapted to be secured to the sides of a tractor for vertical swinging movement relative thereto and having a connecting portion adapted to extend across the front of the tractor, an upper support frame adapted to be secured to the tractor, means for adjustably supporting the yoke from the upper support frame, track following rollers secured to the connecting portion of the yoke and adapted to support the yoke from railroad rails, support means secured to the connecting portion of the yoke and having parts adjustable laterally and vertically relative to the yoke, hinge means carried by said support means at one side of the yoke, a main blade secured at one end to said hinge means in an upright position and extending outwardly at an angle and along one side or the yoke, a brace hingedly attached to the extending portion of the main blade and adapted to be hingedly attached to the tractor for holding the main blade at a desired angle relative to the side of the yoke, means for adjustably supporting the main blade at a desired grading angle, a ballast sloping blade adjustably attached to the main blade near the hinge means, and a shoulder sloping blade adjustably attached to the extending end of the main blade, said main blade having a grading edge intermediate said ballast and shoulder sloping blades.

4.. A road bed and ballast grading attachment for tractors and the like which are adapted to run along the rails of a railroad track during the grading of the ballast and road bed outside of the ties which support the rails and comprising, in combination, a support yoke adapted to be secured to the sides of a tractor for vertical swinging movement relative thereto and having a connecting portion adapted to extend across the front of the tractor, an upper support frame adapted to be secured to the tractor, means for adjustably supportin the yoke from the upper support frame, track following rollers secured to the connecting portion of the yoke and adapted to support the yoke from railroad rails, support means secured to the connecting portion of the yoke and having parts adjustable laterally and vertically relative to the yoke, hinge means carried by said support means at one side of the yoke. a main blade secured at one end to said hinge means in an upright position and extending outwardly at an angle and along one side of the yoke, a brace hingedly attached to the extending portion of the main blade and adapted. to be hingedly attached to the tractor for holding the main blade at a desired angle relative to the side of the yoke, means for adjustably supporting the main blade at a desired grading angle, a ballast sloping blade adjustably attached to the main blade near the hinge means, a shoulder sloping blade adjustably attached to the extending end of the main blade, said main blade having a grading edge intermediate said ballast and shoulder sloping blades, and a wing plate extending forwardly at an angle from the surface of the main blade at a position near the outer end of the ballast sloping blade to push ballast inwardly of the shoulder.

5. A road bed and ballast grading attachment for tractors and the like which are adapted to run along the rails of a railroad track during the grading of the ballast and road bed near the ends of the ties which support the rails and comprising, in combination, support means adapted to be secured to the tractor and including a support yoke adapted to be secured to the sides of a tractor with a portion thereof extending across the front of the tractor and having mounted thereon a horizontally swingable hinge plate, rail engaging support elements on the front of the yoke, a main blade secured at one end to said hinge plate in an upright position and extending outwardly therefrom, said main blade being swingable in a vertical direction relative to the hinge plate, a brace havin one end hingedly attached to the ll main blade and its other end adapted to be hingedly attached to the tractor for normally holding the blade in said outwardly extending position, means for determining the vertical angular position of the blade relative to the hinge plate, a'ballast sloping blade adjustably attached to the main blade at the end thereof near the hinge plate, and a shoulder sloping blade adjustably attached to the extending end of the main blade.

6. A road bed and ballast grading attachment for tractors and the his which are adapted to run along the rails of a railroad track during the grading of the ballast and road bed near the ends of the ties which support the rails and comprising, in combination, a support yoke adapted to be secured to the tractor and having mounted at one end thereof a horizontally swingable hinge plate, a main blade secured at one end to said hinge plate in an upright position extending outwardly therefrom, said main blade being swingable in a vertical 0 ctlon relative to the hinge plate, a brace having one end. hingedly attached to the main blade and its other end adapted to be hinge'dly attached to the tractor for normally holding the blade in said, outwardly extending position, means for determining the vertical an ular position or" the main. blade relative to the hinge plate, a ballast sloping blade adjustably attached to the main blade at the end thereof the hinge plate, a shoulder sloping blade adjustably attached to the extending end of the main blade, and a wing plate extending forwardly at an angle fro-m the, surface of the main blade at a position near the outer end of the ballast sloping blade to push ballast inwardly of the shoulder.

7. A road and ballast grading attachment for tractors and the like which are adapted to run along the rails of a railroad track during the grading of the ballast and road bed near the ends of the ties which. support the rails and comprising, in combination, support means adapted to be secured to the tractor and including a substantially U-shap-ed yoke having a, horizontally swingable hinge plate mounted at one side of the closed end of the yoke, a main blade secured at one end to said hinge plate in an upright position and extending outwardly therefrom, said main blade being swingable in a vertical direction relative to the hinge plate, a brace having one end hingedly attached to the main blade and its other end adapted to be hingedly attached to the tractor for normally holding the blade in said outwardly extending position, means for determining the vertical angular position of the main blade relative to the hinge plate, a ballast sloping blade adjustably attached to themain blade at the end thereof near the hinge plate, and a wing plate extending forwardly at an angle from the surface of the main plate opposite that towhich the brace is attached and at a position near the outer end of the ballast sloping blade to push ballast inwardly.

8. In a ballast grading attachment for tractors and the like which are adapted to run along the rails of a railroad track the combination comprising, a support yoke adapted to be rotatably secured to the sides of a tractor for vertical swinging movement relative thereto, said yoke having a portion adapted to extend across one end of the tractor, means including a pair of rotatably mounted flanged rollers secured to said portion of the yoke for following railroad rails and supporting said yoke, and a grading blade adjustably mounted on one side of the yoke adjacent said portion thereof.

9. In a side grading attachment for tractors and the'like, the combination comprising a grading blade, and means for supporting said blade which includes means providing guide bearings, a support member linearly movable in said guide bearings, mea'is comprehending a screw connected to one end of the support member and a rotatable member co-acting with the screw for adjusting the position of the support member, a transverse beam secured to the other end of the support member and carrying two sleeve bearings in spaced relation, a slide rotatable and linearly movable in said sleeve bearings, a hinge plate secured tosaid slide intermediate said sleeve bearings, and means comprehending a. screw and a co actin rotatable member for determining the position of the slide longitudinally of said sleeve bearings.

MURRAY E. BURNS. GEORGE M. BONNELL.

REFERENCES CITED The following references are of record in the 7 file of this patent:

UNITED STATES PATENTS Number Name Date 1,191,756 Baker July 18, 1916 1,322,688 Geelhart Nov. 25, 1919 1,533,198 Mann Apr. 14:, 1925 1,718,550 Ferris et a1 June 2c, 1929 1,818,750 Protzeller Aug. 11, 1931 2,266,633 Gill Dec. 16, 1941 2,312,255 Lowderm'ilk Feb. 23, 19 i?)