US2797506A

US2797506A - Rooter blade assembly

Info

Publication number: US2797506A
Application number: US435782A
Authority: US
Inventors: Hilliard Joy
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-06-10
Filing date: 1954-06-10
Publication date: 1957-07-02
Anticipated expiration: 1974-07-02

Description

July 2, 1957 Q R 2,797,506 7 ROOTER BLADE ASSEMBLY Filed June 10, 1954 s Sheets-Sheet 1 1 WWW A'rronnavs 'July 2, 1957 J. HILLIARD 2,797,506

. ROUTER BLADE ASSEMBLY 3 Shets-Sheet 2 Filed June 10, 1954 V A@ 39' M I -BY Tam/mi WM a vi.

TTORNEYS July 2, 1957 J. HILLIARD 2, 5 v

ROOTER BLADE ASSEMBLY Filed June 10, 1954 3 SheetsSh'eet 3 Y qwa Q/IQ N N/Q/Q/Q/ A Q INVENTOR. 30v Huumwv ATTORNEYS 2,797,506. rammed July 2,1951

' 2,797,506 ROUTER BLADE ASSEMBLY Joy Hilliard, Nevada City, Calif. Application June 10, 1954, Serial No. 435,732 7 Claims. (Cl. 37-145) This invention relates to accessory equipment for earth moving equipment, such as bulldozers and the like.

Heretofore it has been more or less standard practice to provide bulldozers having conventional pusher or scraper blades with accessory blades or rakes of various types to render the bulldozer more versatile and better able to perform the numerous types of jobs required of this type of equipment. Thus, for example, it has been proposed in the past to mount on the conventional pusher blade of a bulldozer a plurality of elongate depending relatively narrow blades (hereinafter referred to broadly as rooter blades) which in operating position are adapted to extend below the bottom edge of the standard pusher blade of the bulldozer. The rooter blades provide, in effect, a plurality of individual digging or raking teeth which are particularly useful for digging into and loosening hard or rocky soil, or for uprooting stumps or rocks, or for performing similar tasks which could not be accomplished practically, if at all, using only the pusher blade of the bulldozer.

One disadvantage common to all rooter blade equipment of the above type and of which I have knowledge resides in their lack of flexibility in being able to expeditiously change over from pusher blade to rooter blade operation. In this regard, it is necessary in present day commercial equipment to physically remove or readjust the positions of the rooter blades with reference to the pusher blade in order to use the pusher blade in conventional manner. However, to make the change-over entails o much time and effort that it is the usual practice, in working a job requiring both rooter blade and pusher blade operations, to employ two bulldozers-one equipped with the rooter blades and the other not, whereby said bulldozers can be operated alternately with one another to accomplish the dual task of rooting (with the rooter blades) and earth moving (with the pusher blade).

As will appear hereinafter, it is a principal object of the present invention to provide a unique combination rooter blade and pusher blade assembly that permits an operator of a bulldozer to rapidly and easily convert from one operation to the other without requiring removal, replacement, manual readjustment, or physical handling in any fashion of the rooter blades.

More particularly, the particular embodiment of the present invention and which will be described hereinafter in greater detail comprises in combination with a conventional bulldozer pusher blade, a plurality of rooter blades individually hingedly mounted at their upper extremities to the front face of the pusher blade. Each rooter blade defines in profile an upwardly extending shank, and a downwardly forwardly inclined foot portion. The arrangement of the rooter blades is such that when the pusher blade of the bulldozer is elevated out of ground engaging contact, the foot ends of the rooter blades depend below the lower edge of the pusher blade with the toe ends thereof pointing downwardly and forwardly whereby when the bulldozer is driven forwardly, the rooter blade feet will dig themselves into the soil in the desired manner.

The arrangement is also such'that by backing the bulldozer a few feet to the rear and by lowering the pusher blade, the rooter blade feet 'will swing upwardly out of soil embedment so that the heel portions of the rooter blade feet rest upon the top of the ground with the toe portions of the blades pointing upwardly. With the rooter blades in this latter position, the bulldozer can be operated in its usual fashion with the pusher blade in contact with the ground pushing earth ahead of the bulldozer and with the heel portions of the rooter blades riding on top of the ground ahead of the pusher blade.

From the foregoing, it is seen that in order to move the rooter blades to nonworking position during intervals when it is desired to operate the bulldozer using the pusher blade, or conversely, to move the rooter blades to working position when it is so desired, it is unnecessary for the operator or other personnel to physically remove, replace, or physically handle or adjust the rooter blades as is required in prior art mechanisms of simila character.

Another important and unique feature of the invention resides in the'fact that mean are provided for hingedly mounting the rooter blades withreference to the pusher blade of the bulldozer in several alternative positions whereby the angular displacement between the direction in which the rooter blade feet extend and the medial plane of the pusher blade can be selectively varied. In this regard, it is common practice to employ rooter blades of the character above mentioned in conjunction with both straight blade and angle blade bulldozers. In conventional equipment of which I have knowledge, there is no simpleeifective way provided whereby the angle between the rooter blades and the pusher blade can be varied. Although there have been developments in the past toward providing angularly adjustable rooter blades, such prior art structures of which I have knowledge have either utilized elaborate and expensive assemblies including remote control adjusting mechanisms, for example, or, in the simpler devices, the physical effort, time and/ or equipment required to angularly adjust the blades have been of such significance that these latter type devices have not met with general or widespread commercial acceptance. The ability to angularly adjust the rooter blades with respect to the pusher blade is of particular importance when it is necessary to angle the pusher blade to the right or left with reference to the direction of travel of the bulldozer. and extremely desirable to maintain the digging feet of the rooter blades pointed substantially in the direction of travel of the bulldozer at all times, regardless of the angle at which the pusher blade itself may be positioned. The principal reason for this, of course, is that pointed feet of rooter blades are by their nature designed to dig or rake pointing in a straight ahead position; Thus, when the rooter blades are angled with respect to'the direction of travel of the bulldozer, their movement through rocky or hard ground, for example, is not only anin-j efficient use of the blades, but such movement will impart considerable torsional force to the blades whichicanre:

sult in damage to the bladesthemselves or to, the means employed for mounting the blades to the bulldozer.

- In the embodiment of the invention shown, novel trunnion means are provided forhingedlysupporting the rooter blades of the present.v device in .any one of several alternate positions of angular displacement with refer:

ence to the pusher blade whereby the said rooter blades can be mounted to point or extend substantially in the direction of bulldozer travel regardless of the angular. position of the pusher blade itself.

Other objects of the invention are to provide a rooter.

blade assembly of the character hereinabove briefly mentioned which is of simple, yet extremely rugged con-. struction, and which may be relatively economically manufactured as accessory equipment for installation in.

substantially any commercial make or model of bulldozer or similar. earth moving equipment.

Other numerous objects and advantages of the present,

More specifically, it is both important invention will become apparent upon reading the following specification and referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each ofthe'severalviews."

In the drawings: l

Fig. .1 lSi a perspective view of a typical commercial make of :bulldozer with a rooter blade assembly embodying the invention installed as an accessory thereto;

Fig.2 is an enlarged sectional view taken approximately on line 22 of Fig. 1.

Fig. 3 is an enlarged fragmentary perspective view partially insection of the lower end of a rooter blade assembly.

Fig. 4 is a sectional view taken on line 44 of Fig. 5.

Fig. 5 is a top plan view of the trunnion assembly showing the yoke member in a first position of use.

Fig. 6 is the same as Fig. 5 and showing the yoke member in the second position of use.

Fig. 7 is the same as Fig. 5 and showing the yoke member in a third position of use.

Fig. 8 is a sectional view taken on line 8-8 of Fig. 5.

Fig. 9 is a view in front elevation of the trunnion assembly.

Fig. 10 is a schematic side elevational view of a bulldozer with rooter blades attached shown in nonworking position.

Fig. 11 is the same as Fig. 10 but showing the rooter blades in working position.

Figs. 12, 13 and 14 are schematic top plan views of a bulldozer with rooter blades attached, and illustrating various position of angular displacement between the rooter blades and pusher blades.

Referring now more particularly to the drawings, a bullodzer of more or less conventional design and construction is indicated generally at A, the said bulldozer being provided with a pusher blade also of conventional design and indicated generally at B. A plurality of rooter blades indicated generally at C are shown as being hingedlysupported to the pusher blade B by a plurality of trunnion assemblies indicated generally at D.

The bulldozer A is shown as being provided with the usual side arms 10 which can be individually extended or retracted to angle the pusher blade to the right or left with respect to the direction of travel of the machine. Moreover, the bulldozer A is also provided with the usual suitable mechanism, such as hydraulic lifters 11, for raising and lowering the pusher blade B into and out of ground engaging contact.

Each of the rooter blades, heretofore indicated generally at C, defines in profile an upwardly extending shank 12 and aforwardly and downwardly inclined foot. portion 13. The toe portion of the foot 13 may be tipped or capped with a suitable conventional armored boot such as indicated at 14. The upper end of each rooter blade is hingedly supported to the pusher blade B by a trunnion assembly, heretofore designated at D, and tobe hereinafter described in more specific detail. The inner edge of shank 12 of each rooter blade is preferably arcuately contoured in substantial conformance to the concave contour of the pusher blade. The lower portion of shank 12 is preferably notched as at 16 at a point above the heel portion 17 of the shank to provide clearance be-,

tween the rooter. blade and the usual cutting edge 18 provided on the pusher blade. Bearing pads or plates, indicated at 19, each being formed with three shank receiving slots 21, 22 and 23, are rigidly affixed, as by welding, to the pusher blade in association with the rooter blades. The axes of adjacent slots are shown as being relatively angularly displaced from one another at approximately to receive the shank of the rooter blades in their several alternate positions of angular displacement with respect to the pusher blade as will more fully appear. The principal function of the bearing pads 19 is to provide bearing surfaces through which direct thrust from the rooter blades to the pusher blade can be efliciently transmitted at adequately reinforced points along the pusher blade where the pads 19 can be located.

Each trunnion assembly, heretofore designated generally at D, is shown as comprising an open ended trunnion housing 24 substantially rectangular in side, front, and rear elevation (as shown in Figs. 4, 8 and 9) and truncated triangular-shaped in top and bottom plan (as shown in Figs. 5, 6 and 7). Each trunnion housing 24 may be securely mounted, as by welding, within an appropriately proportioned rectangular cut-out formed through the pusher blade. The front open end of each housing is preferably mounted flush with adjacent surfaces of the pusher blade face and with the larger or base end of each housing projecting rearwardly of the pusher blade.

The trunnion assemblyD further comprises a yoke member, indicated generally at 26, and comprising more specifically a bifurcated head portion 27, and a rearwardly extending stern portion 28 rectangular in crosssection. The bifurcated head 27 is aperturcd to receive a horizontal pivot pin 29 which may be removably secured in position by a conventional nut 31 and cotter pin 32. Pin 29 provides, of course, the hinged connection between each rooter blade and the trunnion assembly. The head portion of the yoke member 26 is preferably made substantially larger in its cross-sectional area than the rearwardly extending stem portion 28 so as to provide laterally protruding arcuate bearing surfaces such as indicated at 33. These bearing surfaces 33 are proportioned and contoured to bear against top and bottom arcuate bearing flanges 30 provided at the front portion of each housing 24, and against the arcuate bearing surfaces formed on the trunnion wedge blocks to be described hereinafter. Moreover, and as will more clearly appear, the purpose of providing the bearing surfaces 33 for engagement with complementary bearing surfaces 30 of the housing is to insure direct transmission of thrust and shock forces imparted to the yoke members from the rooter blades directly to the casing and to the pusher blade of the bulldozer which is constructed and reinforced to adequately withstand such forces.

The yoke member 26 can be removably supported within housing 24 in any one of three alternative positions as shown in Figs. 5, 6 and 7, for example. Fig. 5 discloses the yoke positioned within the casing with the lengthwise axis of the stem portion 28 extending coaxially with the medial lengthwise axis of the trunnion housing. To insure a secure and snug fit of the yoke within its housing, first and second wedge blocks indicated at 36 and 37, respectively, are provided. Each wedge block, in turn, is rectangular in side elevation, and is truncated triangulanshaped in plan. Each Wedge is also formed with a pair of divergently disposed working surfaces, indicated at 36 and 36 and at 37 and 37 respectively, the said working surfaces of each wedge being angularly displaced with respect to one another at one-half the angle between the divergently disposed

side walls

24 and 24 of the truncated triangular-shaped trunnion casing 24. When the yoke member 26 is secured in housing 24 in its position as shown in Fig. 5, the Wedge blocks 36 and 37 are inserted from the open base or rear end of the casing to provide a solid wedge blocking between opposite sides of stem 28 and the sides of housing 24. The narrow or forward end of each wedge block terminates in an arcuate bearing surface such as indicated at 42 and 43, respectively. Each of these arcuate surfaces defines a segment of the arc of flanged bearing surface 30 of housing 24, and said surfaces 42 and 43 are adapted to engage against the arcuate bearing surfaces 33 provided on the enlarged head of yoke 26 when the latter is positioned in the trunnion housing as will be explained more fully.

The yoke 26 and the wedge blocks 36 and 37 can be maintained in their proper positions within the housing by a plurality of pins indicated at 38, 39 and 40 which the yoke member can be secured within housing 24. Thus,

for example, Fig. 6 discloses stem 28 extending parallel and in contact with the side 24 of the housing 24 whereby the lengthwise axis of the stem projects outwardly from the housing at an angle of approximately 30 with reference to the medial lengthwise axis of the housing. When in this position, the wedge blocks 36 and 37 are disposed between stem 28 and the side wall 24 of the housing.

-It is further noted that wedge block 36, in its position shown in Fig. 6, is inverted bottom-side up from its position as shown in Fig. 5. Inverting the wedge in this fashion, serves to align the pin receiving aperture in said wedge with the central housing aperture whereby the same three pins can be employed to secure the yoke and wedge blocks in their arrangement shown in Fig. 6 as employed in the arrangement shown in Fig. 5. Moreover, inverting wedge block 36 bottom-side up also functions to bring the arcuate bearing surface of the block into proper alignment and in bearing contact with the arcuate shaped bearing surfaces 33 of the yoke whereby uniform bearing contact between the yoke, housing, and wedge blocks is established.

Fig. 7 is similar to Fig. 6 but discloses the stem portion of the yoke in bearing contact with the side Wall 24 of the housing and with wedge blocks 36 and 37 wedged between the stern and the side wall 24 of the housing. Block 37 is shown as being inverted bottomside up from its position shown in Fig. for reasons hereinabove explained with reference to the arrangement of parts shown in Fig. 6.

The operation of the device will now be described.

The principal aspects relating to the operation of the rooter blade assembly embodying the invention can be readily understood by having particular reference to Figs. 10-14, inclusive. Figs. 10 and 11 illustrate how the rooter blades may be moved into and out of working position simply through backward or forward maneuvering of the bulldozer and through raising and lowering of the pusher blade. In this regard, it will be recalled that it is an important object and advantage of the present invention to be able to move the rooter blades into and out of working position without having to alternatively remove, replace or otherwise directly handle the rooter blades.

Fig. 11 shows the rooter blades in digging contact'with the earth. In order for a'bulldozer operator to utilize the rooter blades in the manner shown in Fig. 11, it is only necessary to raise the pusher blade sufficiently high to permit the rooter blades to swing downwardly about their trunnion axes 29 to a position whereat the lower shank portions of the blades are in contact with slotted bearing pads 19 and whereat the foot portions 13 of the blades depend below the pusher blade and point downwardly forwardly in contact with the ground surface whereby forward movement of the bulldozer will cause the rooter blades to dig themselves into the ground. It is appreciated, of course, that the depth in which the blades dig into the earth can be regulated through raising or lowering of the pusher blade using the conventional pusher blade controls on the bulldozer.

As explained heretofore, it is frequently desirable in earth moving operations to alternatively employ the rooter blades to loosen soil, for example, so that the pusher blade can then be used'to level or push the loosened soil asi'de.

Fig.1'0 discloses how the pusher blade may be employed o-accomplish this latter purpose without encountering any practical interference from the rooter blades. More specifically, Fig. 10 illustrates the pusher blade in ground contact and the rooter blades extending angularly forwardly of the pusher blade with the heel portions of the rooter blade feet gliding on top of the ground ahead of the pusher blade. It is observed, of course, that the rooter blade feet point angularly upwardly which eliminates any tendency of the blades to dig themeselves into the ground ahead of the pusher blade.

T 0 move the rooter blades from their digging position shown in Fig. ll to their nondigging or nonworking position shown in Fig. 10, it is necessary only for an operator to back the bulldozer up several feet and to simultaneously lower the pusher blade into ground contact. This simple maneuvering automatically forces the rooter feet upwardly out of soil contact and to their position shown in Fig. 10.

Figs. 12, 13 and 14 disclose more or less schematically another important aspect concerning the operating principles of the present invention. More specifically, these latter figures disclose how the rooter blades may be hingedly supported by trunnions D and with the axes of the rooter blade feet placed at different angular positions with respect to the medial plane of the pusher blade. Thus, for example, when the rooter blades are employed in operations where the pusher blade is straight and is neither angled to any substantial degree to the right or left, the rooter blades are each hingedly supported by the trunnion arrangement shown in 'Fig. 5 whereby the trunnion yoke 26 projects outwardly in the direction of the medial lengthwise axis of the housing and which orients the pivot pin 29 parallel with the median plane of the pusher blade. It is also seen that the rooter blade feet when suspended by the trunnion arrangement of Fig. 5 project outwardly at an angle perpendicular to the pusher blade which, in the arrangement shown in Fig. 12, is also in the directionof travel of the bulldozer.

Fig. 13 shows the pusher blade angled to the left at approximately 30 with reference to the 'direction of travel of the bulldozer. The rooter blades, however, are shown as pointing in the direction of travel of the bulldozer and at an angle of approxi-ately 60 with reference to the medial plane of the pusher blade. In this arrangement, the rooter blades are all hingedly supported to the pusher blade by the trunnion arrangement shown in Fig. 6, for example.

Fig. 14 is similar to Fig. 13 and shows the pusher blade angled to the right at approximately 30 with reference to the direction of travel. The rooter blades, however, are again shown as pointing straight ahead in the direction of travel and at an angle of approximately 60 with reference to the medial plane of the pusher blade. The trunnion arrangements shown in Fig. 7 may be employed to support the rooter blades when suspended in the manner shown in Fig. 14.

It is appreciated, of course, that at times it may be desirable to entirely remove the rooter blades from the bulldozer. This may be accomplished either by disconnecting the blades from their trunnions through removal of pins 29, or the blades with yokes attached may be removed as a unit from the trunnion casings. When the bulldozer is operating without the blades attached, it may be considered preferable to remove the yokes 26 from their trunnion housings 24 so that the bifurcated head portions 27 of the yokes are not left projecting outwardly from the pusher blade where they could possibly get in the way or become damaged in certain types of operations' Solid blocks of wood (not shown) of substantially the same size and shape as stern portions 28 of the yokes, and which can be suitably apertured to receive one of the

pins

38, 39 or 40, may be inserted and secured within the trunnion housings in lieu of the yoke stems when the latter are removed from said housings.

Although the present invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is understood that certain changes and modifications may be practiced within the spirit of the invention as limited only by the scope of the claims appended hereto.

I claim: V

1. In combination with earth moving equipment of the type having a pusher blade movable upwardly and downwardly into and out of ground engaging contact: a rooter blade defining in profile an upwardly extending shank and a forwardly projecting foot portion; means hingedly supporting the upper extremities of said shank relative to said pusher blade for pivotal movement of said rooter blade from a digging position, whereat the blade shank is disposed adjacent and substantially parallel to the face of the pusher blade and with the foot of said rooter blade inclined downwardly and depending below the bottom edge of said pusher blade, to a nondigging position, whereat the shank extends from its hinged connection angularly downwardly and forwardly of the pusher blade face and with the foot of said rooter blade inclined upwardly whereby the heel of the foot portion of the rooter blade is adapted to ride on top of the ground surface in front of the pusher blade when the latter is moved downwardly in ground engaging contact; and means for selectively varying the relative angular displacement between the axis of the foot of said rooter blade and the face of said pusher blade measured in a horizontal plane.

2. In combination with earth moving equipment of the type having a pusher blade movable upwardly and downwardly into and out of ground engaging contact: a rooter blade defining in profile an upwardly extending shank and a forwardly projecting foot portion; a trunnion assembly carried by said pusher blade and including a horizontal pivot hingedly supporting the upper extremities of said shank for pivotal movement of said rooter blade from a digging position, whereat the blade shank is disposed adjacent and substantially parallel to the face of the pusher blade and with the foot of said rooter blade inclined downwardly and depending below the bottom edge of said pusher blade, to a non-digging position, whereat the shank extends from its hinged connection angularly downwardly and forwardly of the pusher blade face and with the foot of said rooter blade inclined upwardly whereby the heel of the foot portion of said rooter blade is adapted to ride on top of the ground surface in front of the pusher blade when the latter is moved downwardly in ground engaging contact; said trunnion assembly comprising means for selectively varying the angular displacement between the axis of said horizontal pivot relative to the face of said pusher blade within a horizontal plane, whereby said rooter blade can be hingedly supported relative to said pusher blade in different alternative positions of angular displacement relative to the face of said pusher blade measured in a horizontal plane.

3. The combination of claim 2 and wherein said trunnion assembly comprises: a yoke member having a bifurcated head carrying said horizontal pivot and-a rearwardly extending stem portion; a trunnion housing defining a front opening rigidly secured to said pusher blade with said front opening disposed adjacent the face surface of said pusher blade; and means for removably supporting the stem portion of said yoke within said housing in different alternative positions of angular displacement between the axis of said stem and the medial axis of said open front housing.

4. The combination of claim 3 and wherein said last named means comprise first and second wedge blocks alternatively positionable within said housing in a first position with said blocks disposed to opposite sides of said stem portion between said stem portion and the opposite sides of said housing and in a second position with both of said blocks disposed to the same side of said stem portion between said stern portion and one side of said housing.

5. The combination of claim 2 and wherein said trunnion assembly comprises: a yoke member having a bifurcated head carrying said horizontal pivot and a rearwardly. extending stem portion substantially rectangular .in cross-section; a trunnion housing substantially truncated triangular-shaped in plan and rectangular in crosssection open at its front and base ends; said housing rigidly secured .to said pusher blade with the front opening of said housing disposed substantially flush with the face surface of said pusher blade and with the base end of said housing projecting rearwardly of the face surface of said pusher blade; said housing proportioned to receive through its front open end the stem portion of said yoke member in alternative positions of angular displacement between the longitudinal axis of said stem and the medial lengthwise axis of said housing; and means comprising wedge blocks proportioned to be inserted interiorly of said housing from its open base endfor wedging the stem portion of said yoke securely therein in any one of its said alternative positions of angular displacement.

6. A trunnion assembly for hingedly supporting a root er blade or the like to a pusher blade provided on earth moving machinery, comprising: a trunnion housing sub stantially truncated triangular-shaped in plan and rectangular in cross-section defining divergently extending side walls; said housing adapted to be rigidly secured to a said pusher blade with its truncated front opening disposed substantially flush with the face surface of said pusher blade and with the open base end of said housing projecting rearwardly of said pusher blade; a yoke mem ber having a bifurcated head carrying a horizontal pivot for attachment to a said rooter blade and a rearwardly extending stem portion substantially rectangular in crosssection; the stem portion of said yoke member positionable alternatively within said housing in a first position with the stern projecting in a direction of the medial lengthwise axis of said housing, in a second position with the stem disposed parallel toand in contact with a first side wall of said housing, and in a third position with the stern portion parallel to and in contact with the second side wall of said housing; first and second similarly constructed wedge blocks insertable through the open base end of said housing; each wedge block defining first and second divergently extending working surfaces disposed at an angle to one another substantially equal to one-half the angle between the divergently extending side walls of said housing; said wedge blocks positionable within said housing to wedge the stem portion of the yoke member securely therein in a first alternative position with said first and second wedge blocks disposed to either side of the stem between said stern and opposite side walls of the housing when said stem occupies its said first position in said housing, in a second alternative position with both of said wedge blocks disposed to the first side of said stern when the latter occupies its said second position in said housing, and in a third alternative position with both wedge blocks disposed to the second side of said stem when the latter occupies its third position in said housing.

7. A trunnion assembly according to claim 6 and wherein registering apertures are formed through the top and bottom members of said housing and through said stem portion of said yoke member and through said first and second wedge blocks; and means comprising pins insertable throughsaid registering apertures for removably securing said stem and said wedge blocks within said casing in any of the said alternative positions occupied by said stem and said wedge blocks.

References Cited in the file of this patent UNITED STATES PATENTS 258,263 Stroud May 23, 1882 2,262,415 Williams et al Nov. 11, 1941 2,420,027 Austin May 6, 1947 2,632,261 Ferris Mar. 24, 1952 2,679,701 Busque June 1, 1954