US2116010A - Variable leverage brake rigging - Google Patents

Description

May' 3, 1938. B. H. BROWALL 2,116,010

- VARIABLE LEVERAGE BRAKE RIGGING Filed Feb. 28, 1935 3 Sheets-Sheet l y 3, 1938. B. H. BROWALL 2,116,010

VARIABLE LEVERAGE BRAKE RIGGING Filed Feb. '28, 1935 5 Sheets-Sheet 2 y 1938. B. H. BROWALL 2,116,010

VARIABLE LEVERAGE BRAKE RIGGING Filed Feb. 28, 1955 s Sheets-Sheet s lure/27%) ram aj/ 6i zw Patented May 3, 1938.,

um'reo STATES 2,116,010 VARIABLE LEVERAGE BRAKE RIGGING Bert Henry Browall, Malmo,

Aktiebol to Svenska Malmo, Sweden,

Sweden, assignor aget Bromsregulator,

a corporation of Sweden Application February 28, 1935, Serial No. 8,746

r 6 Claims.

This invention relates to equalized vehicle brake riggings, especially railway freight car brake riggings, of the type in which the two main pull rods which are connected to the free ends of the cylinder and floating levers, respectively, and extend towards the opposite ends of the car, respectively, are disposed on opposite sides of the longitudinal axis of the car, and in which, therefore, the floating lever is inverted in relation to the cylinder lever.

The principal object of the invention is to provide an improved variable leverage arrangement for equalized brake riggings of the said type. Another object of the invention is to provide in equalized brake riggings of the said type an improved variable leverage arrangement of the general character described and illustrated by Setterwall in the U. S. Patent No. 1,949,187, dated February 27, 1934, in which, for the purpose of selectively producing different brake applying leverages, one or more auxiliary levers are connected between the cylinder and floating levers to which the main pull rods are connected. More particularly, the invention has for its object to provide a variable leverage arrangement which can be built in moreeasily and to greater advantage in brake riggings of the said type on cars new existing. where the brake rigging, as originally constructed, has an invariable brake applying leverage suited to the empty weight of the car, and where the brake cylinder and the fixed fulcrum of the floating lever are so disposed that the connection rod between the cylinder and floating levers is substantially parallel to the longitudinal axis of the car. In such a case, if an attempt is made to build in the variable leverage arrangement of the construction shown, for instance, in Fig. 3 or Fi drawings of the said U. S. 'Patent between the cylinder and floating out otherwise changing the brake tain difliculties will be met with.

It is the object of the invention to reduce or eliminate these diflficulties orderthat the nature of the advantages gained thereby m stood, the nature of the said difliculties will be declared in the following with reference to Figs. 1 and 2 on the accompanying drawings.

In the accompanying drawings:

Figs. 1 and 2 illustrate diagrammatically and in plan view the variable leverage arrangement as constructed accordin ..respectively, in the said U..S. Patent No. 1,949,187,

rigging, .cer-

invention and the ay be fully underg. 4 in the No; 1,949,187,, lovers withand, therefore, in

g to Fig. 3 and Fig. 4,

but as applied to an existing brake rigging of the kind referred to above. 1 1

Figs. 3 and 4 illustrate diagrammatically and in plan view two constructional forms of the invention as applied to. a brake rigging having a Variable leverage arrangement similar to that shown in Fig. 1 and Fig. 2, respectively.

Fig. 5 illustrates in the same way another manner of realizing the principle underlying the invention.

Fig. 6 is a detail section on a larger scale of parts shown in Fig. 5.

Fig. 7 illustrates diagrammatically and in plan view a further constructional form of the invention. 1

Fig. 8 illustrates in the same manner still another constructional form of the invention.

Referring to Figs. 1 and 2, i represents the brake cylinder and 4 and I! the cylinder and floating levers, respectively, which in the original construction of the brake, rigging are interconnected by means of a connection rodlinked to the said levers in the points 31 and 38, respectively, so that these points divide the two levers in equal leverage ratios K respectively, suited to the empty weight of the car. The main pull rod 56!. connected to the free end of the floating lever I l and the main pull rod 51) connected to the cylinder lever 4 are disposed on opposite sides of the longitudinal} axis of the car and, consequently, the cylinder j lever and the floating lever extend towards opposite sides of the car from the brake piston head 2 and the fixed fulcrum 3, respectively, the construction being such that the aforesaid connection rod between the cylinder and floating levers is substantially parallel to the longitudinal axis of the car.

In building in the variable leverage arrangement in the said existing brake rigging the aforesaid original connection rod between the cylinder and floating levers is substituted by a connection rod l2 or 20 which is linked to the cylinder lever and an auxiliary lever 7 or I8 in the points 3'! and I I as shown in Figs. 1 and 2, respectively, and a further brake lever connection 8 1 or 22 is established between thecylinder lever and another auxiliary lever 6 as shown in Fig. l, or between the cylinder lever 4 and the same auxiliary lever l8 as shown in Fig. 2. This further connection 2 and operativealternately with the connection rod I2 or 20 by means of the switchable abutment I5, is linked to the cylinder lever 4 in a point 39 dividing the said lever in a leverage ratio suited to loaded car. The floating lever I1 is connected to said auxiliary levers or lever B, I or l8 by an articulated or single link rod Illa, or 220., respectively, which is linked to the floating lever I! in a point 48 dividing said lever in such a leverage ratio 75 that the pulling force transmitted to the pull rod 511 at a braking operation will be equal to the pulling force transmitted to the pull rod b, irrespective of whether the transmission of the braking power takes place at the lower leverage ratio suited to empty car, or at the higher leverage ratio suited to loaded car.

Considering the construction as shown in Fig. 1, in which the levers Band 1 have the leverage ratios 2 and a 21 a respectively, the following relations will be found. (a) Braking at the lower leverage ratio suited to empty car. The shiftable abutment I5 is then in the right hand position and supports the end of the lever I. The lever B is unsupported and non-operative. 'Ihe pull on rod P designating the force from the push rod of the brake cylinder. The pull on rod 5a: (1) In the original condition with rod l2 connected directly to point 38 I a+b a .3 QaE- b I+ I b (2) In the altered condition in which the auxiliary levers B and 1 are added according to the U. S. Patent No. 1,949,187, and the end portion of rod l2 adjacent the lever I1 is replaced by rod la. The values of n and 0 must 'be selected so that the pull on rod 50. will still be equalto a P'Z; The pull on rod So can be expressed by the equation a+b 31 o QEP b n c+d wherein c'+d'=a+b'.

Obviously the condition the left hand position and supports the lever 6,

while the lever l is unsupported and nonoperative.

It may be shown in the same manner as above that the condition for equal output forces of the cylinder lever and the floating lever is exactly the same as that expressed by the equation 2 jc a b It is thus to be seen that although the known 7 construction certainly is operative, its application on existing cars leads to the drawback that the olm it will be found that in order to obtain equality in respect of the pulling forces in the two pull rods 5a and 5b when braking at the higher leverage ratio as well as when braking at the lower leverage ratio, the connection rod 22a by necessity must take an oblique position. Such obliquity is undesirable due to the lateral stresses or loads on the fulcrums and the piston head 2 resulting therefrom.

The present invention has for its object to avoid obliquity in the brake rigging, while maintaining a proper action of the variable leverage arrangement for selectively producing the desired different brake applying leverages. This result is obtainable, when applying the invention to an existing brake rigging of the kind set forth with reference to Figs. 1 and 2 herein, by connecting the connection rod IOa or 22a not to the floating lever I! but to an additional lever which has a fixed fulcrum disposed substantially on the axis of the brake cylinder, and by connecting the floating lever IT to the said additional lever.

Referring to Figs. 3 and 4, the same reference characters are used therein as in Figs. 1 and 2, respectively, for corresponding details and, therefore, it will be unnecessary to describe again such details as already have been described with ref erence to Figs. 1 and 2. It is to be noted, however, that the connection rod a in Fig. 3 and .22a in Fig. 4 is connected to the free end of an additional lever 42 having a fixed fulcrum 43 disposed substantially on the axis la of the brake cylinder I. The length of this additional lever 42 is equal in Fig. 3 to n and in Fig. 4 to c. The additional lever 42 and the floating lever H are interconnected by means of a connection rod Hlb in Fig. 3 and 22b in Fig. 4, which is linked to the floating lever H in the point 38 and to the additional lever 42 in a point at a distance ya from the pivot point 43. This construction works properly for selectively producing the desired different brake applying leverages and gives the desired equality in respect of the pulling forces transmitted to the two main pull rods 5a and 5b when braking at the higher leverage ratio as well as when braking at the lower leverage ratio, as may be shown in the same manner as in the case of the known construction in Fig. 1, while obtaining the desirable parallelism of all the connection rods in the construction.

The invention, however, can also be realized in a manner resulting in a much more simple conbetween the fixed fulcrum 43 for a brake applying leverage "used in the constructions hereinbefore described for selectively producing the desired different An example of such shown in Fig. 5 on in which the same brake applying leverages. a simplified construction is the accompanying drawings,

reference characters are used as in Figs. 3 and 4 for corresponding details. According to this constructionthe original connection rod between the points 31 and 38 on the cylinder and floating levers 4*and II, respectively, is divided into two parts 44 and 45.

The part 44 is connected between the point 3'! on the cylinder lever 4 and a point 46 on an additional lever 42, and the part 45 is connected between the said point 46 and the point 38 on the floating lever I1. The distance the lever 42, which {is disposed on the axis la tance between the piston head 2 and the point 37 on the cylinder lever 4, so that the "rods 44 and 45lwill be substantially parallel to the longitudinal axis of the car. on' the cylinder lever 4, inder lever in a leverage Between the point 4'! which divides the cylratio adapted to give suited to loaded car, and the point 49 on the additional lever 42 there is establisheda connection 48, the distance between the point 49 and the fixed fulcrum 43 being equal to the distance between the point 41 and the pistonhead 2. In the rod 44 there is provided a device for setting this rod in and out of action for selectively producing the desired different brake applying leverages, the lower leverage for empty car being obtained when the said rod44 is active as a power transmitting member at brakin and the higher leveragefor loaded car being obtained when the said rod 44 is made inactive so that the power transmission is taken over by the connection rod 48. In the example shown the said device is in the form of a so called rod coupler having a coupling member 50 which is movable in and out of active position in which it couples the rod 44 to the lever 42, by means of a link 52, a bell crank lever 53 pivoted on the fixed fulcrum 43, a link 54 and a crank arm 55 on a transverse shaft 56. This shaft 56 may extend to the sides of the car and be provided with crank handles for setting the coupling member 50 manually, or a device of any suitable kind may be provided for setting the coupling member automatically in dependence upon the load of the car, for instance a device of the character disclosed in the German patent specification No. 598,085. Preferably the rod coupler is so constructed that when in active position it leaves a certain slack 5| in the rod 44. This slack serves the same purpose as do the slacks provided for by the elongated holes 13 and I9 in the constructions shown in Figs.' 1-4 herein, and the purpose of these slacks may not be described here since it is evident from the specification pertaining to the hereinbefore mentioned U. S. Patent No. 1,949,187 and forms no feature of the present invention. In the rod 48 there is provided an elongated hole 57 for at least one of the connection bolts 4'! and 49 in order to allow for the relative movement of the points 47 and 49 towards each other, which takes place when braking at the lower leverage ratio.

When pivoting the coupling member 50 on the bolt. 46 by which the connection rod 45 is fasof the brake cylinder and the point 46, is equal to the distened to the lever 42, most favourable disposal of the strains on the bolt is obtained if the pivoted end of the coupling member 50 is bifurcated and embraces the bifurcated adjacent end of the rod 45, as shown in Fig. 6. For the rest the construction of the device for selectively setting the connection rods 44 and 48in and out of action forms no part of the present invention, and this device may beconstructed in any suitable manner or be of any suitable type, for instance of the type described and shown in the co-pcnding application Ser. No. 752,167, filed November 8, 1934, or of the type disclosed in the French Patent No. 762,438 or of the type disclosed in co-pending application Ser. No. 15,691 filed April 10, 1935. Further there is no-hindrance to providing each of the rods 44 and 48 with a device for positively setting the rod in and out of action, and for such purpose devices of the characters disclosed in the U. S. Patents Nos. 1,963,224 and 1,980,328 may be used. Of course it is also possible to provide more than two connection rods between the cylinder lever 4 and the additional lever 42 for selectively producing more than two different leverage ratios, if desired. Such a constructional form of the invention is illustrated in Fig. 7, in which, in addition to the connection rod 48, there are two connection rods 44' and 44" connected tothe cylinder lever 4 at 31'and 37", respectively, and

adapted to cooperate with rod couplers 50 and 54", respectively, which are pivoted to the additional lever 42 and are operable selectively by mechanism 52', 53', 54', and 52", 53", 54", re-

spectively. Finally the connection between the cylinder lever 4 and the additional lever 42 can also be constructed in such a way as to make possible a progressive variation of the brake applying leverage, for instance by adopting a variable leverage mechanism substantially of the character disclosed in the U. S. Patent No. 621,653

or of the character disclosed inthe U. S. Patent No. 1,937,267. Fig; 8 illustrates a constructional form of the invention, in which the cylinder lever 4 and the additional lever 42 are interconnected by means of a connection rod 59 which is secured to the levers by means of pins 60 engaged in elongated slots 6! in the levers and slidable therein by a mechanism 62 as disclosed in the aforesaid US. Patent No. 621,653, for the purpose of progressive variation of the leverage ratios of the two levers 4 and 42. In allthese cases the invention enables all the connection rods to be disposed in parallelism to the longitudinal axis of the car.

If it should be desirable, for some reason or the other, to abstain from linking both the rods 44 and 45 to the same point 46 on the additional lever 42, it is permissible to displace the connecting point of the rod 45 on the lever 42 a small distance towards or away from the fixed fulcrum 43. When doing so also the connecting point 38 for the rod 45 on the floating lever I! should be displaced a corresponding distance towards or away from the fixed fulcrum 3 of the lever ll. If, in such a case, the object is to build in the variable leverage arrangement in an existing brake rigging where it is impossible to alter the local position of the entire lever I! by a parallel-displacement thereof, or to alter its total length, the rod 45 will take a somewhat oblique position, but the lateral stresses arising therefrom will be taken up by the fixed fulcrums 3 and 43 and will have no influence upon the piston head 2. In the construction of new cars, however, it is possible to select such a position for the fixed fulcrum 3 andlor such a length of the lever I! that the connecting point 38 on the lever I! will be so aligned with the displaced connecting point for the rod 45 on the lever 42 that the rod 45 is maintained in parallelism to the other connection rods.

What I claim and desire to secure by Letters Patent is:-

I. In a variable leverage brake rigging of the character described, a brake cylinder, a cylinder lever, a floating lever, an additional lever, a, nonshiftable fulcrum for said additional lever disposed substantially on the axis of the brake cylinder, means for simultaneously varying the leverage ratio of the cylinder lever and the additional lever, and a connection between the additional lever and the floating lever, said connection being substantially parallel to the axis of the brake cylinder and so arranged in relation to said floating and additional levers, that the output force of the floating lever will be substantially equal to the output force of the cylinder lever for both the high and low leverage setting of the brake rigging.

2. In a variable leverage brake rigging of the character described, a brake cylinder, a cylinder lever, a floating lever, an addtional lever, a nonshiftable fulcrum for said additional lever at a fixed point disposed substantially on the axis of the brake cylinder, means for selectively producing diiferent brake applying leverages connected between said additionallever and the cylinder lever, and a connection between said additional lever and the floating lever, said connection being substantially parallel to the axis of the cylinder lever and so arranged in relation to said floating and additional levers, that the output force of the floating lever will be substantially equal to the output force of the cylinder lever for both the high and low leverage setting of the brake rigging.

3. In a variable leverage brake rigging of the character described, a brake cylinder, a cylinder lever, a floating lever, an additional lever, a nonshiftable fulcrum for said additional lever at a fixed point disposed substantially on the axis of the brake cylinder, a plurality of connections between said additional lever and the cylinder lever for selectively producing different brake applying leverages, and a connection between said additional lever and the floating lever, said connection being substantially parallel to the axis of the brake cylinder and so arranged, that the output force of the floating lever will be substantially equal tothe output force of the cylinder lever for both the high and low leverage setting of the brake rigging.

4. In a variable leverage brake rigging of the character described, a brake cylinder, a cylinder lever, a floating lever, an additional lever, a nonshiftable fulcrum for said additional lever at a fixed point disposed substantially on the axis of the brake cylinder, substantially aligned connections between the cylinder lever and the additional lever and between the latter and the floating lever, respectively, and means including said connection between the cylinder lever and the additional lever for simultaneously varying the leverage ratio of the cylinder lever and the additional lever, said substantially aligned connections between the cylinder lever and the additional lever and between the latter and the floating lever being substantially parallel to the axis of the brake cylinder and so arranged, that the output force of the floating lever will be substantially equal to the output force of the cylinder lever for both the high and the low leverage setting of the brake rigging.

5. In a variable leverage brake rigging of the character described, a brake cylinder, a cylinder lever, a floating lever, an additional lever, a nonshiftable fulcrum for said additional lever at a fixed point disposed substantially on the axis of the brake cylinder, a connection rod between the cylinder lever and the additional lever connected to the cylinder lever in a point dividing the cylinder lever in a lower leverage ratio, a second connection rod between the cylinder lever and the additional lever connected to the cylinder lever in a point dividing the cylinder lever in a higher leverage ratio, a connection rod between the additional brake lever and the floating lever connected to the latter in a point dividing the same in a leverage ratio equal to the said lower leverage ratio of the cylinder lever, all the said connection rods being substantially parallel, and means for selectively setting the said connection rods between the cylinder lever and the additional lever in and out of action at braking.

6. In a variable leverage brake rigging as claimed in claim 5, the additional feature that the said means includes a coupling member having a bifurcated end pivoted on a fastening bolt on the additional lever for the connection rod between the latter and the floating lever and embracing the adjacent end of said connection rod.

BERT HENRY BROWALL.

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