US2893326A

US2893326A - Suspension for railway cars and the like

Info

Publication number: US2893326A
Application number: US360454A
Authority: US
Inventors: Kenneth A Browne; Sergei G Guins
Original assignee: CHESAPEAKE AND OHIO RAILWAY Co
Current assignee: CHESAPEAKE AND OHIO RAILWAY Co
Priority date: 1953-06-09
Filing date: 1953-06-09
Publication date: 1959-07-07
Anticipated expiration: 1976-07-07

Description

July 7, 1959 K. A. BROWNE ET AL 2,893,326

' SUSPENSION FOR RAILWAY CARS AND THE LIKE Filed June 9, 1953 4 Sheets-Sheet 1 INVENTORS KENNETH A. BROWNE 8| SERGE! G. GUINS ATTYS.

y 1959 K. A. BROWNE ETAL 2,893,326

SUSPENSION FOR RAILWAY CARS AND THE LIKE 4 Sheets-Sheet 2 Filed June 9, 1953 E a N vwm W .5 TR wv I M u m A a M HG t x% u MW m K8 5% V! a E m 0 Nu .u on on m mm II. //7 3 mm On 0 Illlr 8 N o .nn nn mm .m ow v k 3 L: z x x N.

y 7, 1959 K. A. BROWNE ET AL 2,893,326

SUSPENSION FOR RAILWAY CARS AND THE LIKE IN V EN TORS KENNETH A.

BROWNE SER El GUINS July 7, 1959 K. A. BROWNE ETAL 2,393,326

SUSPENSION FOR RAILWAY CARS AND THE LIKE 4 Sheets-Sheet 4 Filed June 9, 1953 A M MS 0 WN OwW M RG R V EB N mm a K I. w w W E J h 7R u F O 6 W M F I i F w FIG. 9

ATTYS.

I kip United States Patent SUSPENSION FOR RAILWAY CARS AND THE LIKE Kenneth A. Browne, Lakewood, and Sergei G. Gains, Olmsted Falls, Ohio, assignors to The Chesapeake and Ohio Railway Company, Cleveland, Ohio, at corpora= tion of Virginia Application June 9, 1953, Serial No. 360,454

6 Claims. (Cl. 1054) This invention relates to railway cars in which the car bodies are suspended so as to be capable of banking inwardly when rounding curves at high speeds and more particularly to a suspension system for such cars.

A preferred embodiment of our invention is described herein as applied to a car of the single axle, semi-trailer type which in a train is attached at its front end to the rear of the car ahead. Cars of this type are advantageous from the standpoints of economy, of construction and operation, and can be safely operated at higher speeds than conventional cars, because in a train each car is steered into curves by the car or locomotive ahead of it. Thus it is possible to operate trains of such cars safely on curves at speeds well in excess of superelevation speeds, i.e., in excess of the speed at which the resultant of gravity and centrifugal force acting on the car is normal to the plane of the inner rail and the superelevated outer rail. The present invention is concerned with an improved car-body suspension wherein the car body banks inwardly under the influence of centrifugal force to maintain the floor of the car body substantially normal to the resultant of gravity and centrifugal force acting on the body as the car travels around curves at high speeds, thereby improving the riding comfort of the passengers.

A general object of our invention is to provide an improved car-body suspension system which permits the car body to bank into curves when the car travels around the curves at speeds in excess of superelevation speeds. Another object is to provide such a suspension system wherein the linkage of the system is connected to the car body at a level below the center of gravity of the car body. Another object is to provide a suspension system which effectively insulates the car body from shocks and vibrations. Other objects are the provision of a suspension system that is light in weight and yet is able to maintain the car stable under all operating conditions; the provision of a suspension that is compact and thereby minimizes the loss of revenue passenger space; the pro vision of a suspension system for semi-trailer type cars which effectively eliminates self-excited lateral car oscillations and swaying; and the provision of a suspension which is simple in design, economical to produce and rugged in construction.

. These and other objects of our invention will become apparent from the following description of a preferred form thereof, reference being had to the accompanying drawings.

Figure 1 is an elevation of a portion of a train with cars embodying our invention.

Figure 2 is an enlarged side elevational view showing the suspension apparatus of our invention.

Figure 3 is an enlarged fragmentary view of the apparatusof Figure 2 with a portion thereof broken away to show details of construction.

Figure 4 is a horizontal section taken on the line 4-4 of Figure 2.' c

1 5 and 6 are end views of the car of Figure 2 ice in the upright and inwardly banked positions, respectively, the end of the car being broken away to show the suspension apparatus.

Figure 7 is a schematic plan view of a train of cars embodying our invention and showing the angular disposition or toe-in of the radius rods which form a part of the suspension system.

Figure 8 is a schematic plan view of the suspension system showing the steering effect caused by lateral displacement of the front ends of the radius rods when the car body pivots laterally.

Figure 9 is a schematic end view of the car and illustrates the steering efiect of vertical displacement of the front ends of the radius rods when the car body pivots laterally.

It has previously been proposed to construct railway cars in which the bodies are suspended from above their centers of gravity, these are so-called pendulum cars. When a car of this type negotiates a curve at a speed in excess of superelevation speed, centrifugal force acting on the center of gravity causes the car body to move outwardly pendulum-wise relative to the axle and wheels. This, in effect, adds to the superelevation of the track insofar as the passenger inside the car is concerned and banks or tilts him comfortably into the curve. The suspension systems of pendulum cars, however, being connected to the car body well above the center of gravity, necessarily are bulky and cut down substantially on the revenue space of the car. According to the present invention the suspension linkage is connected to the car body below the center of gravity thereof, thus greatly reducing the loss of revenue space, and at the same time the desired inward banking of the car body is obtained.

The semi-trailer type railway car which we prefer to describe as an embodiment of our invention is illustrated in a portion of a train shown in Figure 1 having cars C and C. The rear end of each car is supported on a pair of wheels W journalled on a transverse axle A. The cars preferably are coupled together and their front ends supported by a coupler comprising a coupling pin P projecting from the rear end of each car and adapted to engage in a corresponding socket, not shown, in the front end of the adjacent rear car and to be releasably locked therein by suitable locking means. The front end of each car is equipped with retractable dolly wheels D which are cranked down in order to support the front end of the car when uncoupled from the car ahead; the wheels are raised and lowered by means of a crank H projecting from each side of the car. The details of the coupling are described more fully and claimed in the copending application of Kenneth A. Browne, Serial No. 354,724, filed May 13, 1953, now Patent No. 2,843,056, dated July 15, 1958, and entitled Coupler Apparatus.

The wheels W and axle A supporting the rear end of each car body are connected to the frame of the car body by a suspension system indicated generally at S which normally maintains the car body in a vertically upright position but which is arranged so that the car body banks inwardly, see Figure 6, relative to the wheels and axle when the car passes around a curve at a speed exceeding the superelevation speed. The car suspension system with which our invention is concerned consists of identical parts symmetrically located on opposite sides of the car. Therefore, in the following paragraphs and in the drawings, like parts on opposite sides have like reference characters.

The axle A is carried by suitable journals within the journal box housings 8 on each end of the axle. Each journal box preferably is connected by a main strut 10 having arms 11 and 12 to the underside 13 of a shock absorber or spring 14, the struts being pivotally connected to both the journal box and the underside of the spring. The spring 14 preferably takes the form of a bellows-type air spring, the bellows being composed of-fabric-reinforced. rubber or the, like. Plates 15 on the upper ends of the. air springs 14 are secured to the frame of the car and hence the weight of the, rear portion of the car. body is carriedby the springs. lt'will be noted that the upper end of strut HP is. closer to the center of the car than its lower end; i.e., the strut slants inwardly as shown in Figures 5 and 6; this arrangement, as explained below, constrains the carv body to bank Wardly when the body as a whole moves outwardly with respect to the axle under the influence of centrifugal force.

Since the vertically disposed air springs have no substantial strength in the horizontal plane, a pair of horizontal restraining linksi and ljare providedfor each spring 14 to prevent substantial lateral displacement ofthe springs and yet permit free vertical compression a'nd expansionof the same; The; links in and li diverge outwardly and are connected by longitudinally spaced bracket 19 to the sides of the car body frame. Thus lateral and fore-and-aft movements of the bottoms ofthe springs are prevented. The links are connected to the bracket 19 through suitable rubber mountings which permit limited pivoting of the links in a vertical plane to accommodate vertical expansion and contraction of the air spring 14.

Inasmuch as the center of gravity of the car body, indicated at CG in Figures 5 and 6,, is above the plane of the connection of the supporting struts with the bottoms of the springs 14, the car body is in unstable equilibrium on the pivoted struts 16. Therefore, in order to maintain the car body in an upright position and yet permit the car body to move outwardly under the influence of centrifugal force, the connection of the lower end of each of the strut arms 11 and 12 to the journal box housing 8 preferably is made through a torsion spring that preferably takes the form of a torsion-elastic bushing 21, one of these bushings being shown in detail in Figure 3. The journal box housing 3 preferably has integrally formed radial lugs 22 extending fore and aft of the housing and one of the bushings 21 is mounted on each of these lugs. The lugs 22 have a common axis 24 which preferably is substantially horizontal and perpendicular to the axis of the axle A, and is the axis about which strut arms 11 and 12 pivot when the car body swings outwardly. Bumpers 25 projecting inwardly from the strut arms are adapted to engage the sides of the car body as the struts pivot'and thereby limit the degree of car body roll.

Each of the torsion-elastic bushings 21 comprises an inner rigid sleeve 26, an outer rigid sleeve 27 and an intermediate sleeve 28 comprised of rubber or rubberlike material which is bonded to the inner and outer sleeves. on one of the mounting lugs 22 and has an annular flange 29 at its inboard end secured by bolts 30 to a boss 31 on the journal box housing 8. The outer sleeve 27 preferably comprises two half clamps secured together along mating flanges 33 by means of clamping bolts 33'. The lower ends of the strut arms 11 and 12 are semi-cylindrical in shape as indicated at 34, see Figures 5 and 6, to fit closely around the outer sleeve 27 and have flanges 35 secured tothe sleeve flanges 33 by bolts as shown. Thus the strut arms 11 and 12 are supported directly upon the journal box housing 8 through these torsionelastic bushings. The rubber sleeve 28 of each bushing preferably is substantially unstressed torsionally when thecar body is upright, or normal to the plane of the axle A-. The bushings thus act as torsion springs and resiliently hold' the (21- body in upright position. When the'car body swings outwardly as the train passes around a. curve at a speed in. excess of superelevation speed, each strut pivots with respect to the. axle and journal box housing about the horizontal axis 24 and torsional- The inner sleeve 26 of each bushing fits snugly 1y stresses the rubber sleeves 28 of the bushings 21. The bushings 21 thereafter function to restore the car body to the vertical position after the train has passed the curve.

The expansible bellows-type air spring 14 is closed on the bottom and is pneumatically connected at the top by conduit 36, see Figures 2, 5, and 6, to a tank 37 carried on the car body above the bellows and which con stitutes an airreservoir for the spring system. Preferably tank 37 is inflated with air until the pressure in the bellows is sufficient to withstand car body loads with normal deflection. When the bellows is compressed or extended in response to shocks or changes in load, air flows into and out of the tank 37 through conduit 36. The action of the spring is damped by an adjustable valve 33 disposed in conduit 36 to control the flow of air between the bellows and the tank 37. The stnuctural. details of the air spring system and the'da'mping valve do not constitute a part'of' our invention and no claim is rn-aderherein to this subject matter;

The bottom 13 of the spring 14 is rigidly connected to the inner ends of the horizontal links 16 and 17, and is connected to the top of each supporting strut 10 through a universal joint generally indicated at 41. In practice, we prefer that each strut beset at an angle of approximately 65 to horizontal with the air spring extending vertically from the top of the strut when the car is symmetrically loaded in a neutral or vertically upright position.

In order to prevent substantialglongitudinal displacement of the axle and wheel assembly with respect to the car body, I have provided a radius rod 43 on each side of the car, see Figures 2- and 4. The rear ends of the radius rods are connected to the journal box housing 8 and their forward ends are connected to the underframe of the car body. The rear connection of each radius rod is made to a depending flange 44 on the housing 8 through a rubber or rubber-like mounting 45 and the forward end is similarly attached through a rubber mounting 4-6 to a bracket 47 fastened to the underframe of the car at a point spaced forwardly from the axle. We prefer that the radius rod 43 incline upwardly from the journal box housing 8 in order tofreduce the danger of interference with objects along the. roadbed and to improve the riding qualities. and stabilit'y of the car as explained below.

When trains comprised of trailer-type cars are in motion, there is a tendency forinormal lateral vibrations in each car to develop into oscillatory motion of substantial amplitude and thereby cause the car'to sway and shimmy generally in the manner ofa caster. This occurs because the normally minor lateral' vibrations in the car body and in the wheel and axle assembly tend to be complementary and therefore self-exciting. In order to eliminate such vibrations of the car, we prefer to displace the forward ends of the radiusrods inwardly an equal amount so that each radius rod is toed-in and makes an angle x with the longitudinal axis of the car, see Figure 4. We prefer that the angle of toein of the pair of radius rods on each car be equal and that the amount of toe-in be such that an extension of the longitudinal axes of the rods willintersect at a point intermediate the ends of one of the forward cars, preferably the adjacent forward car. As shown in Figure 7, for example, the extendedaxes of radius rods 43 of car C meet at a point V intermediate the endsof the adjacent forward car C Similarly V on the car C represents the point of intersection 'of the extended axes of rods 43,, located on car C The effect of such toe-in of the radius rods is to create a center of oscillation of the wheel and axle assembly of each car, that is, points V and V respectively, which is. different from the center of oscillation of the car body, namely, the coupling between the cars, so that self-exciting oscillations and shimmying are substantially eliminated. In practice, with cars approximately 31 feet in length, an angle of toe-in, that is, angle x, of the radius rods, of 3% to 4 /z give satisfactory results.

The operation of the suspension system embodying our invention is shown in Figures 5 and 6. The supporting struts and the horizontal stabilizer links 16 and 17 preferably connect to the bottoms 13 of the air springs 14 slightly below a horizontal plane containing the center of gravity CG of the car when the car is in the upright position shown in Figure 5. The torsion-elastic bushings 21 are substantially unstressed in this position of the car body and each strut extends upwardly at an angle approximately 65 to the horizontaL, As the car passes around a curve to the left as shown in Figure 6, centrifugal force causes the car body to move outwardly (to the right as shown in Figure 6) with respect to the center of the axle. The struts 10 pivot clockwise as viewed against the resistance offered by the bushings 21. Since the struts 10 slant inwardly, clockwise rotation of the left hand strut farther away from the vertical results in lowering the left hand or inner side of the car' body while clockwise rotation of the right hand strut brings it closer to vertical and results in raising the right hand or outer side of the car body. Thus, the car body is banked into the curve, the parts preferably being so proportioned and designed that the vertical axis of the car body substantially coincides with the resultant of gravitational and centrifugal forces acting on the car .body. This makes it possible to round curves at high speeds without subjecting the passengers to distressing outward forces. a

The amount of lateral displacement of the lower part of the car body is greater than the displacement of the bumpers 25 on the strut arms on the right side, as viewed, and hence these bumpers will ultimately engage the car body as the displacement continues and thereby limit the degree of inward banking of the body. The torsionelastic bushings 21 act in opposition to the centrifugal force and return the car body to the upright position as shown in Figure 5 when the centrifugal force acting on the car diminishes. i

The inward and upward inclination of the forwardly extending radius rods 43 on each car has an effect on the steering of the wheels W which will be understood more fully by reference to Figures 8 and 9. Figure 8 shows the steering effect of radius rod toe-in and Figure 9 the steering effect of upward inclination of the rods; these effects are separated in the drawing, but it will be understood that both effects occur simultaneously when the car body is displaced. Referring to Figure 8, CL and CL represent the positions of the centerline of the car body prior to and after lateral displacement due to centrifugal force respectively, and M represents the amount of lateral displacement at the forward ends F and F of the right and left, as viewed, radius rods 43, the amount of displacement being exaggerated for puroses' of illustration. The positions of the radius rods 43 before and during lateral displacement are indicated in solid and broken lines, respectively. As the car passes around the curve at a speed above superelevation speed to the left and as the car body moves outwardly to the right as viewed in Figure 8, the front end F of the radius rod on the left side moves inwardly to the right a distance M to point F which causes its opposite or rearward end R; to advance forwardly to the point R Similarly, the forward end F of the right hand (as viewed) radius rod 43 moves outwardly a distance M to point F and causes its opposite or rearward end R to move backwardly to point R The resultant of this forward and rearward movement of the rear ends of the radius rods 43 is an angular displacement of the wheel and axle assembly so that the axis K of the axle shifts clockwise as viewed to the position indicated at K. Thus the wheels are steered outwardly or oppositely to the direction of steering caused by pull of the adjacent forward car.

The steering effect of upward inclination or toe-up of the radius rods 43 is opposite to the steering effect of toe-in. Referring to Figure 9 showing a schematic end view of a car, the solid lines 43 again represent the position of the radius rods when the car body is in the neutral or upright position, and the dotted lines of the position of the rods when the car body has moved outwardly but has banked into the curve. Again let F and R designate the front and rear ends, respectively, of the right hand radius rod and F the corresponding ends of the left radius rod. As the car body rolls to the right as viewed, the point F on the left hand radius rod moves downwardly a distance N to point F and point F on the right hand radius rod moves upwardly a distnce O to point F The effect of this vertical movement of the front ends of the rods is to cause rear end R of the left rod to move backwardly and the corresponding end R on the other rod to move forwardly. This action causes the axle A to which the radius rods are connected at points R and R to pivot or rotate in a counterclockwise direction as viewed in Figure 8 in opposition to the above described rotational effect of toe-in of the radius rods. We prefer that these steering effects of toe-in and upward inclination of the radius rods be substantially balanced against each other.

Changes and modifications and improvements to the above described embodiment of our invention may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore we do not wish the patent to be limited in any manner inconsistcut with the invention as defined in the appended claims.

We claim:

1. In a railway train comprising a plurality of trailertype cars, each car comprising a car body having a frame, each car being pivotally supported at the front on the car ahead and being supported at the rear on a single axle and wheel assembly having journal boxes at the ends of the axle, the improvement of a suspension system for each of said cars comprising a pair of supporting struts, one strut being pivotally connected to each journal box for pivoting about a horizontal axis disposed transversely of the axle, each strut extending upwardly and inwardly from its associated journal box, a pair of vertically acting springs mounted on opposite sides of the center plane of the car body and secured to the underside of the frame of said car body, said springs being vertically spaced from the car axle and being laterally inwardly spaced from the respective sides of the car body, one strut being pivotally connected to the bottom of each of said springs, the points of connection of the struts to the springs being below the plane of the center of gravity of the car body, a laterally extending restraining link assembly associated with each spring, each link assembly being made up of a pair of links resiliently connected at longitudinally spaced points to the car body frame and converging inwardly and pivotally connecting to the un derside of the adjacent spring, the resilient connections of said links to the car body frame permitting limited pivotal movement of the links about a horizontal axis, means between the journal box and the lower ends of the respective supporting struts for resiliently holding the car body in an upright position comprising a rigid inner sleeve anchored to the journal .box, a rigid outer sleeve fastened to one of the supporting struts, and a resilient sleeve disposed between and secured to said rigid sleeves and adapted to be stressed torsionally when said supporting struts pivot relative to the respective journal boxes, and a radius rod on each side of the car for longitudinally positioning said wheel and axle assembly with respect to the car body, the rear end of each radius rod being resiliently connected to a journal box and the front end of each radius rod being connected to the car body frame, the rods being toed in toward each other, the angle of 7 toe-in of said rods being substantially equal and such that projections of the axes of said rods will intersect at a point otherthan at the adjacent forward coupling connection of the cars.

2. In a railway train comprising a plurality of trailertype cars, each car comprising a car body having a frame, each car being pivotally supported at the front on the car ahead and being supported at the rear on a single axle and wheel assembly having journal boxes at the ends of the axle, the improvement of a suspension system for each of said cars comprising a pair of supporting struts, one strut being pivotally connected to each journal box for pivoting about a horizontalaxis disposed transversely of the axle, each strut extending upwardly and inwardly from its associated journal box, a pair of vertically acting springs mounted on opposite sides of the center plane of the car body and secured to the underside of the frame of said car body, said springs being vertically spaced from the car axle and being laterally inwardly spaced from the respective sides of the car body, one strut being pivotally connected to the bottom of each of said springs, the points of connection of the struts to the springs being below the plane of the center of gravity of the car body, a laterally extending restraining link assembly associated with each spring, each link assembly being made up of a pair of links resiliently connected at longitudinally spaced points to the car body frame and converging inwardly and pivotally connecting to the underside of the adjacent spring, the resilient connections of said links to the car body frame permitting limited pivotal movement of the links about a horizontal axis, means between the journal box and the lower ends of the respective supporting struts for resiliently holding the car body in an upright position comprising a rigid inner sleeve anchored to the journal box, a rigid outer sleeve fastened to one of the supporting struts, and a resilient sleeve disposed between and secured to said rigid sleeves and adapted to be stressed torsionally when said supporting struts pivot relative to the respective journal boxes, and means for bracing said axle and wheel assembly against longitudinal movement relative to said car body.

3. A suspension system for a railway car comprising a car body having a frame and supported atone end on a single axle and wheel assembly, said assembly including journal boxes on the ends of the axle, comprising a supporting strut pivotally connected to each journal box for pivoting about a horizontal axis disposed transversely of the axle, said struts extending upwardly and inwardly from each journal box, a pair of bellows-type air springs each mounted on opposite sides of the center plane of the car body and each being secured to the underside of the frame of said car body, said springs being vertically spaced from the car axle and being laterally inwardly spaced from the respective sides of the car body, one strut being pivotally connected to the bottom of each of said springs, said point of connection of said struts to said springs being below the plane of the center of gravity of the car body, a restraining link assembly associated with each spring, each restraining link assembly being connected to the car body frame, and to one of said springs and bracing said spring against lateral movement while permitting vertical movement of same, means between the journal box and the lower ends of the respective supporting struts for resiliently holding the car body in an upright position comprising a rigid inner sleeve anchored to the journal box, a rigid outer sleeve fastened to one of the supporting struts, and a resilient sleeve disposed intermediately of and secured to said rigid sleeves and adapted to be stressed torsionally when said supporting struts pivot relative to the respective journal box, and

8 a radius rod on each side of the car for bracing said wheel and axle assembly against longitudinal movement relative to the car body, each radius rod being connected at the rear end'to ajournal box andat the forward end to the car beerme.

4: Suspension apparatus for a railway car having a car body 'with a'frarne, a wheel and axle assembly, and journalboxes'on the ends of said axle, comprising, supporting struts mounted on and adapted to pivot relative to said journal boxes and extending upwardly therefrom, the upper ends of said struts being vertically spaced from the frame of said car above each of said journal boxes, spring means connected to and disposed between said upper ends' of said struts and the frame of the car, the height of the point of connection of said spring means to said struts above the axle normally being not greater than the height of the center gravity-off the car body above the axle, and'tors'ion springs-between said struts and said journal'box adapted to urge said struts to position said car body'in a vertically upri'ght neutral position.

5. The combination according to claim 4 in which said point of connection of said springmeans to said struts is lower than'the center of'gravity-of said car body.

6. In a railway car having a vehicle body, an axle, a wheel mounted on and adjacent each end of the axle, and journal boxes on the ends of the axles outwardly of the wheels, a suspension apparatus comprising vertically acting spring means, meansconnecting the upper ends of said spring means to said vehicle body, supporting struts constituting, together with said vertically acting spring means and said means connecting the upper-end of the spring means to the body, the sole connections between the vehicle body and the axle, said supporting struts being connectedat one end to the "lower ends of said vertically acting spring means'and being pivotally connected at the other end to said journal boxes, the pivotal connection between the struts and journalboxes including a torsion sleeve assembly fixed to said struts and journal boxes for urgingsaid vehicle body to a vertically upright position, restraining means connected to and extending transversely between said vertically acting spring means and said vehicle body to limit longitudinal movement of said axle and said suspension apparatus relative to the vehicle body, bumper means acting between a part of said vehicle body and a part of said struts and connected to one of said parts for abutting the other of said parts to limit banking of the vehicle body beyond a predetermined extent.

References Cited in the file of this patent UNITED STATES PATENTS 136,248. Kollock Feb. 25, 1873 1,232,918 Head July 10, 1917 2,225,242 Van Dorn Dec. 17, 1940 2,252,789 Van Dorn Aug. 19, 1941 2,474,471 Dolan June 28, 1949 2,523,113 Hanna Sept. 19, 1950 2,601,928 Walsh July 1, 1952 2,604,857 MacVeigh July 29, 1952 2,605,718 Other et'al. Aug. 5, 1952 2,633,811 Poage Apr. 7, 1953 2,647,470 MacVeigh Aug. 4, 1953 2,685,845 Gassner et al Aug. 10, 1954 2,687,099 'MacVeigh Aug. 24, 1954 2,756,688 Furrer July 31, 1956 2,773,686 Nash -Dec. 11, 1956 2,785,640 Furrer' Mar. 19, 1957 FOREIGN. PATENTS 157,620. Australia .-..-5 July 13, 1954