US2780324A

US2780324A - Combined manual and automatic slack adjuster for the foundation brake rigging of railway freight cars

Info

Publication number: US2780324A
Application number: US246638A
Authority: US
Inventors: Charles M O'boyle
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-09-14
Filing date: 1951-09-14
Publication date: 1957-02-05
Anticipated expiration: 1974-02-05

Description

Feb. 5, 1957 c. M. OBOYLE 2,780,324

COMBINED MANUAL AND AUTOMATIC SLACK ADJUSTER FOR THE FOUNDATION BRAKE RIGGING OF RAILWAY FREIGHT CARS Filed Sept. 14, 1951 ll Sheeb-Sheet 1 INVENTOR CHARLES M. O'BOYLE maw i wq ATTORN Y5 Feb. 5, 1957 I c. M. OBOYLE 2,780,324

COMBINED MANUAL AND AUTOMATIC SLACK ADJUSTER FOR THE FOUNDATION .BRAKE RIGGING OF RAILWAY FREIGHT CARS Filed Sept. 14. 1951 I ll Sheets-Sheet 2 I) n V k &

v '3 R 89 -a FIG 4 a II II II II IIIMI II II II ll ll lll INVENTOR S CHARLES M. O'BOYLE ATTORNEYS Feb. 5, 1957 3, OBOYLE 2,780,324

COMBINED MANUAL. AND AUToMATIc SLACK ADJUSTER FOR THE FOUNDATION BRAKE RIGGING OF RAILWAY FREIGHT cARs Filed Sept. 14, 1951 ll Sheets-Sheet 3 INVENTOR CHARLES M. O'BOYLE BY q ATTORZIJQYS Feb. 5, 1957 c, o' o 2,780,324

COMBINED MANUAL AND AUTOMATIC SLACK ADJUSTER FOR THE FOUNDATION BRAKE RIGGING OF RAILWAY FREIGHT CARS Filed Sept. 14, 1951 ll Sheets-Sheet 4 fi I) l/// ///////I INVENT O R CHARLES "M. O BOYLE W MMM ATTORNEYS 2,780,324 FOUNDATION Feb. 5, 1957 c. M. O'BOYLE COMBINED MANUAL AND AUTOMATIC SLACK ADJUSTER F OR THE BRAKE RIGGING OF RAILWAY FREIGHT CARS 11 SheetS -Sheet 5 Filed Sept. 14, 1951 INVENTOR CHARLES M. o'aoY E BY w w vfi O w ATTORNEYS 2,780,324 FOUNDATION Feb. 5, 1957 c. M. O'BOYLE COMBINED MANUAL. AND AUTOMATIC SLACK ADJUSTER FOR THE BRAKE RIGGING OF RAILWAY FREIGHT CARS Filed Sept. 14, 1951 ll Sheets-Sheet 6 INVENTOR A A Q T-C JL M. O'BOYLE COMBINED MANUAL AND AUTOMATIC SLACK ADJUSTER FOR THE 2,780,324 FOUNDATION IGHT CARS Feb. 5, 1957 BRAKE-RIGGING OF RAILWAY FRE Filed Sept. 14, 1951 ll Sheets-Sheet 7 INVENTOR CHARLES M. O'BOYLE BY WMMQQAMW ATTORNEYS c. M. OBOYLE 2,780,324 OMATIC SLACK ADJUSTER FOR THE FOUNDATION RAILWAY FREIGHT CARS 11 Sheets-Sheet 8 BRAKE RIGGING OF Feb. 5., 1957 COMBINED MANUAL AND AUT Filed Sept. 14,

1% ll m m Ewan 7 ///Q M$ mmvw QQ r Feb. 5, 1957 c. M. OBOYLE 2,780,324 FOUNDATION COMBINED MANUAL AND AUTOMATIC SLACK ADJUSTER FOR THE BRAKE RIGGING OF RAILWAY FREIGHT CARS Filed Sept. 14, 1951 1 l1 Sheets-Sheet 9 nwdt v INVENTOR CHARLES M. C'BOYLE fi w 5 2m 3 E 2,780,324 FOUNDATION Feb. 5, 1957 c. M. O'BOYLE COMBINED MANUAL AND AUTOMATIC SLACK ADJUSTER FOR THE BRAKE RIGGING 0F RAILWAY FREIGHT CARS Filed Sept. 14. 1951 ll Sheets-Sheet l0 INVENTOR CHARLES M, OBOYLE mwdt 2,780,324 FOUNDATION Feb. 5, 1957 c. M. O'BOYLE COMBINED MANUAL AND AUTOMATIC SLACK ADJUSTER FOR THE BRAKE RIGGING OF RAILWAY FREIGHT CARS Filed Sept. 14, 1951 ll Sheets-She INVENTOR Q MR Q CHARLES M. O'BOYLE ATTORNEYS United States Patent COMBINED MANUAL AND AUTOMATICSLACK ADJUSTER FOR THE FOUNDATION BRAKE RIGGING OF RAILWAY FREIGHT CARS The present invention relates to improvements in a combined manual and automatic slack adjuster for the foundation brake rigging of railway freight cars and is a continuation-in-part of my application Serial No. 127,342, filed November 15, 1949, now Patent No. 2,675,894.

The present invention constitutes certain improvements over the Sauvage Patent No. 1,738,395, granted Decemher 3, 1929.

The invention according to my co-pending application aforesaid provided for the manual adjustment or take-up of slack occurring in the brake rigging. It is an object of the present invention to retain, in a somewhat similar form of slack adjuster, the manual feature and to add thereto an automatic device operative Without regard to the manual control to the end that the slack in the brake rigging is constantly taken up so that the brake-shoes constantly maintain a substantially ideal clearance with respect to the treads of the wheels and whereby consequently such brake-shoes are forcibly and reliably oper= Iated within an ideal range oflinear piston travel 'of the piston in thebrake cylinder, for example, within the limits of seven to nine inches which is a recommended rang of such travel. j

Another object of the invention resides in'providing a combined manual and automatic slackadjuster'in which the automatic mechanism is pneumatically actuated by air pressure received from the car air reservoir under'the control of the brake cylinder piston.

It is a further object of the invention to provide an improved slack adjuster in which provision is made for disconnecting the parts to permit of a condition of maximum slack in the brake rigging as when one or more brake-shoes are to be replaced.

It is a still further object of the invention to provide manual controlsfwhich are positioned for operation at the side of the car to obviate-the necessity for theftrainrnan having to personally enter the space beneath the car.

A still further object of the invention is to provide a compact and reliably operating device for-the purposes stated.

With the foregoing and other objects in view, the invention will be more fully 'described hereinafter, and 'will' be more particularly pointed out in hereto. V v g In the drawings, wherein'like symbols refer to like or corresponding parts throughout'the several views,

Figure 1 is a perspective view of. .an improved manual 2,780,324 Patented Feb. 5, 1957 Figure 5 is a longitudinal sectional view taken on the line 5-5 in Figure 1.

Figure 6 is a similar view showing the parts in a subsequent position.

Figure 7 is a side elevational view, with parts broken away and parts shown in section, of the improved slack adjuster showing a further phase in its movement.

Figure 8 is a vertical section taken on an enlarged scale showing the parts in a position subsequent to Figure 7.

Figure 9 is a vertical cross-sectional view taken on the line 9-9in Figure 5.

Figure 10 is a similar view taken on the line 10-40 of Figure 5.

Figure 11 is an end elevational view taken from the right hand end of the device as illustrated in Figure 1.

Figure '12 is a longitudinal fragmentary sectional View taken on the line 12-12 in Figure 9.

Figure 13 is a diagrammatic view of a form of foundation brake rigging showing one application of the improved slack adjuster thereto.

Figure 14 is also a diagrammatic view of a modified form of brake rigging showing right and left hand trucks with the application of the improved slack adjuster thereto.

Figure 15 is also a diagram or plan view of a further modified form of brake rigging as applied to ahopper type of freight car showing the method of including the improvedslack adjuster in such rigging.

Figure 16 is a side elevational view of the arrangement shown in Figure 15.

Figure 17 is a longitudinal sectional view taken through a modified form of slack adjuster.

Figure 18 is a longitudinal sectional view taken through a further modified form of slack adjuster.

Figure 19 is a fragmentary side elevational view of a further modified form of slack adjuster illustrating a nonswiveling form of'take-up pawl.

Figure'ZO is afragmentary perspective view of the cooperating lug arrangement on the housing and pawl of Figure 17. I

Figure 21 is afragmentary side elevational view of a V modified form of device withJthe adjuster cylinderin secthe claims appended v and automatic pneumatic slack adjusterconstructed in accordance with'tne present invention and shown apart from the car and from the brake rigging. v

Figure 2 is an enlarged perspective view of -the detail of the swivel sleeve and the take-up pawl and kick-out V Figure 3isa' vertical sectional view taken ontheline I tion and showing a modified form of piston stop.

Figure 22 is a vertical sectional view similar to Figure 9 showing one of the rotary pawl handles connected by cable for operation from the side of thecar.

Figure23 is a fragme'ntary vertical transverse section through the car frame showing the application of the cablecontrol to the rotary pawl.

Figure-24 is an enlarged vertical transverse section taken through the side sill ofthe car and showing the application of the free end of the cable thereto. Figure 25 is a longitudinal section, similar to Figure 5, of an important modified form of slack adjuster of shortened over-all 'le'ngth and short take-up travel with lost motion both in the rotary pawl and in the rackbar. Figure 26 is a horizontal section taken on the line 26 26 ofFigure 25. a

Figure 27 is a verticaltransverse section taken on the line 27-27 of Figure 25. Figure 28 is a longitudinal vertical sectional view in take-up position, and

#Figure29, is a fragmentary similar view on a larger scale showing a subsequent position of the rotary pawl.

' f Referring more particularly to the-drawings, a'housing is shown comprising a top wall 'iall, a bottom wall 31,

and side walls 32. Within this housing is slidably mounted "a'reciprocating rack -bar33 having at one end portions:

portion of the housing or in a dropped extension thereof as later explained. The rotary pawl 36 is formed with an initial tooth 37, with a circular series of teeth 38 struck on the sameradius with the initial tooth 37, and teeth 39 extending off the circular series of teeth 38 at the end opposite that of the initial tooth 37. The tangential teeth 39 are formed in an offset 40 of the rotary pawl 36. Projecting laterally from the offset are one or more handles or projections 41.

The upper edge of the rack bar 33 is formed with top teeth 42 engageable by a take-up pawl 43 which is carried by and movable with a plunger rod 44 constituting a portion of the automatic take-up mechanism. The plunger rod 44 is driven in a forward direction, that is, to the right in Figures and 6 by air pressure introduced into the regulator cylinder 45 against the rear end of a piston or plunger 46. The take-up pawl 43 is driven in the rearward direction by a spring or springs 47. Such spring 47 is shown in Figures 5 and 6 as a single helical spring wound in an appropriate number of convolutions with one end abutting against the forward end of the piston 46 and the other end engaged against the forward head 48 of the regulator aircylinder 45. The spring 47 forms a helix of suitable length, diameter and lead to apply the necessary force to the take-up pawl 43 in moving the rack bar 33 on its rearward movement, the load of the spring being selected as of requisite strength to take up the slack throughout the brake rigging. If desired the spring may be provided in a plurality of helices, one arranged within the other to exert their combined effects upon the plunger 46, the plunger rod 44, take-up pawl 43, rack bar 33 and entrained brake rigging. The length of the regulator air cylinder 45 and other dimensions thereof, as well as correlative dimensions of the spring or springs 47 will be dependent upon the type and class of brake rigging to which the regulator is to be applied and upon other considerations well known to those skilled in this art.

Air may be introduced into the rear end portion of the regulator air cylinder 45 in any suitable manner, preferably through the rear or pressure head 49 as by means of a pipe 50. One preferred source of air supply will be hereinafter described.

An appropriate cupped washer or other formof seal 51 may be detachably or otherwise mounted on the rear piston head 46 as shown more particularly in Figure 5. and the piston may have an expansive ring or packing 52 at its peripheral edge to engage against the internal wall of the regulator air cylinder 45. The forward end of the plunger 46 may have a sleeve extension 53 to accommodate the rear terminal convolutions of the spring 47. A similar shoulder 54 may be formed upon the rear end of the forward cylinder head 48 to receive one or more of the forward terminal helices of such spring 47 in order to more properly center and orient the spring 47 in the regulator air cylinder 45.

The plunger rod 44 may extend slidably through an appropriate bush 55 mounted in the forward cylinder head 48.

Inasmuch as the compressive and expansive reactions of the spring 47 upon the plunger 46 produce a tendency to rotate such plunger-46 and its plunger rod 44, the take-up pawl 43 is not only pivotally mounted but also swivelly connected to the forward end portions of the plunger rod 44. For this purpose a sleeve 56 is rotatably mounted to the forward end portion of the plunger rod.

44 being held thereto in any suitable manner as by a washer 57 and nut 58 threaded to the forward end portion of such plunger rod.

In the form of the invention shown in Figure 5 the rear end of the sleeve 56 engages against a shoulder 59 produced by a reduction in diameter of the forward end portion of the plunger rod44 that receives the sleeve 56. Incident to this construction torsional movements of the plunger rod 44 may occur without transmitting rotary 2,780,324 a a a motion to the sleeve 56, the plunger rod 44 or its reduced forward end simply rotating freely in the sleeve 56.

The take-up pawl 43 is pivotally mounted on the sleeve 56 as upon the pivot pin 60 shown more particularly in Figures 2 and 3. It will be noted from these figures that the pin 60 is dropped below the axis or longitudinal line of the plunger rod 44 so that the center of oscillation of the take-up pawl 43 is placed well below the axial line of the plunger rod 44, it being desirable, for the type of take-up pawl shown in Figures 1 to 8, to lower the line of thrust from the pivot pin 60 through the take-up pawl 43 to the top series of rack bar teeth 42. This simply tends to make the thrust more direct. The lower free edge of the take-up pawl 43 is formed into a tooth 61 of a form complemental in form and inclination to those of the tooth series 42.

As shown more particularly in Figure 2, the forward upper portion of the take-up pawl is cut away at 62 to produce the side arms 63, which arms straddle the sleeve 56, such arms 63 receiving the pivot pin 60. The arms 63 are continued upwardly and forwardly into upper arms 64, angularly related to the take-up pawl arms 63, the latter arms 64 supporting a kick-out finger or nose 65. This kick-out finger 65 may have a beveled or inclined edge 66 positioned to engage a similar beveled surface 67 on the cylinder head 48 or on the regulator air cylinder 45 or on both. These parts are so related that when the device is in the full line position illustrated in Figure 5 the kick-out finger 65 will have engaged the surface 67 to rotate the take-up pawl 43 about pivot 60 to a position where its tooth 61 is withdrawn upwardly from the rack bar top teeth 42.

The position of the take-up pawl 43 and its kick-out finger 65 is so related to the axis of the pivot pin 60 that the take-up pawl 43, when its kick-out finger 65 is released from the surface 67, will gravitationally seek engagement with the teeth 42 or with the upper surface of the rack bar 33. In other words, the take-up pawl 43 and kick-out finger 65 are biased by gravity to a position of engagement with the rack bar and its teeth 42. As shown most clearly in Figure 5, the sleeve 56 and kickout finger 65 may be so related that in the descended position of the take-up pawl 43 its kick-out finger 65 will rest upon the upper portion of the sleeve 56; in this way limiting the downwardly swinging movement of the takeup pawl 43 and therefore limiting such movement to that found proper for the engagement of the tooth 61 of the take-up pawl 43 with the top series of rack bar teeth 42.

The top wall 30 of the housing may be slotted longitudinally as indicated at 68 to receive the take-up pawl 43.

The regulator air cylinder 45 is attached to the regulator housing. In the instance shown I have illustrated the cylinder 45 as having lugs 69 extending from its lower portion, the axis of the cylinder being arranged substantially horizontally, and'the lugs 69 mating 'With companion lugs 70 projecting laterally from the side walls 32 of the housing. Pins, bolts, or other fastenings 71 are passed through the registering lugs 69, 70.

As shown more particularly in Figures 1, 5, 6 and 7, the regulator air cylinder 45 is attached to the regulator housing at a dropped or downwardly offset portion 30a of the top housing wall 30. Shoulders '72 and 73 are shown as defining the ends of this downwardly stepped upper wall portion 30a. Rearwardly of the shoulder 73 the top housing wall is provided with a perforated end section 74 adapted to receive a bolt or other fastening by which the rear end of the housing is mounted upon a bracket, beam, sill or other portion of the railroad car framework. I

As shown to best advantage in Figure 1, the forward end of the housing is provided with a reinforced and perforated top wall section 75 also to receive fastenings whereby this end of the device may be mounted directly tothe framework of the car or through an appropriate bracket to such framework.

As best seen in Figure 5, the forward end of the rack bar 33 is formed with a slot 76 to receive a floating lever or other lever or part of the foundation brake rigging as hereinafter more fully described, the connection to such floating lever being made by the pin 34.

In order to accommodate such lever and to permit of the movement of the lever in unison with rack bar 33, the side walls 32 are provided with slots 77 shown in Figures 1, 5 and 6.

As seen in Figure 5, a slot 73 is made longitudinally in the bottom wall 31 of the housing in order to permit the lower end of the pin 34 to move back and forth with rack bar 33.

'- As seen to best advantage in Figures 5, 8 and 9, the upper surface of the rack bar 33 is slidably received by the depressed top wall a which thus holds the rack bar 33 in engagement with the pawl 36'. The upper surface of the rack bar 33 may be continuous in the same plane all theway to the forward end through which the pin 34.

engages. The teeth 42 maybe indented within this plane with the free upper edges of the teeth lying in such plane.

As shown more particularly in Figures 4-to 9 inclusive and Figure 12 the rotary pawl 36 is supported by lateral trunnions 79 which are detachably mounted in bearings 8h provided in dropped sections 81 of the side walls 32 of the housing. As shown more particularly in Figure 12 curved entrance slots 82 lead from the bearings 80 upwardly and outwardly over the bearing ledges 83 to permit of the introduction and removal of the trunnions 79 into the bearings 80. Preferably the bearings 80 are larger than the diameter of the trunnions 79 by the amount of some such space as shown at 84 in Figure 12 to permit a certain looseness and play of the trunnions 79 in the bearings 80 to avoid any possible binding of the trunnions in the bearings occasioned by thrust developing from the rack bar 33 through the rotary pawl 36.

The bearings 8%) are spaced apart, as shown in Figure 9. to provide a bottom slot 85 through which the pawl 36 and its olfset portion may move incident to the rotation of such rotary pawl 36.

In Figures 5 and 6 the regulator air cylinder is shown as internally provided with a piston stop 86. The stop 86 is a shoulder formed between the difierential internal diameters of the forward and rear portions of the regulator air cylinder 45. The piston stop 86 will be located in a position to arrest the forward movement of the plunger 46 before the spring or springs 47 are collapsed, that is before the spring convolutions are completely closed against one another.

Referring more particularly to Figure 13, the improved regulator is shown as included in one type of brake rigging in which 87 represents the brake cylinder, 88 the piston sleeve and 89 the rod slidable in the sleeve 88 and pivoted to the brake cylinder lever 91).

in accordance with conventional construction, the

brake cylinder lever 90 is connected by a rod 91 to the live lever 92 of one of the trucks. Such live lever 92 is connected by a bottom rod 93 to the dead lever 94. The bottom rod 93 may extend through or below the bolster. The brake shoes are indicated at 95 and 96 for this particular truck, the wheels of which are indicated at 97 and 98.

A connection is made from the brake lever 90 through a center rod 99 to a floating lever 100. The floating lever 1% is connected by a rod 101 to a live lever 102 to the opposite end truck. lever lid. to the dead lever 1%. The brake shoes are indicated at 165 and 196 as having the proper clearance with respect to the wheels 1W7 and 108.

The floating lever 10% is shown as slidable through the slots. 77 in the side walls 32 of the housing and such lever 1th) is extended toward the side of the car to provide a handle ltl9which provides for the manual actuation of the device. The floating lever 10%) is accommodated in the slot 76 ofthe rack bar 33 to which it is pivotally A bottom rod 103 connects the live connected by the pin 34. The floating. lever may be moved from the full to the dotted line position in Figure 13 either manually by a trainman without the necessity of going between the rails, or this floating lever 100 may be pulled over automatically to the dotted line position by the expansive action of the spring 47 in the air regulater or motor cylinder 45.

The pipe 50 extends over the brake cylinder 87 in a manner illustrated in the Sauvage patent aforesaid. In other words, the pipe 50 enters through the side wall of the brake cylinder 87 at a preselected point where the piston in the brake cylinder 87 will uncover the port to the pipe 50 when such piston travels beyond the ideal maximum linear travel prescribed by authoritative regulatory bodies.

Referring more particularly to Figure 14, a somewhat similar arrangement of brake rigging is illustrated for socailed left hand and right hand trucks in which the brake cylinder lever 9th: is connected by center rod 99a to a reversely positioned floating lever 10%. Lever 100a is equipped with a handle 169a which connects with the improved regulator in a manner similarly shown and described with respect to Figure 13.

Figures 15 and 16 show the application of the improved regulator to a hopper-type car brake installation where the brake cylinder is installed at the end of the car with the brake lever 111 pivoted to the car at its upper end as shown at 112. The lower end of this brake lever 111 is connected by a rod 113 to a lever 114 which in turn is connected to one truck brake installation as shown.

The lever 114 is connected by a rod 115 to the floating lever 116 which is connected by a rod 117 to the truck brake installation at the other end of the car. The floating lever 116 extends through the slotted housing 30 of the regulator and is pivoted by pin 34 to the rack bar 33). The floating lever 116 is extended outwardly to or adjacent the side of the car to aiford a handle 118 for the manual operation of the regulator. The regulater air cylinder is shown at 45.

Referring more particularly to Figure 17, in which a materially shortened device is illustrated, 30c designates the top wall of a very much shortened housing having a slot 68c therein which occupies a more rearward position than the slot in the previous form of the device. In fact the slot 68c is beneath the cylinder.

The rack bar 33c is also shortened and of a somewhat different form in that its upper edge slides along in contact with the top wall 300 of the housing. The forward end of the rack bar is slotted to receive the floating lever pivoted therein by the pin 340.

The rotary pawl 36c meshes with the bottom teeth 35c of the rack bar in the manner previously described.

The engine or motor cylinder 45c is also materially shortened in length and contains two springs 47c and 47d mounted one within the other to secure necessary spring strength and load while minimizing the length of the regulator engine or motor. The plungercarries a stop sleeve 53c entered through a number of convolutions of the inner spring 47d and adapted to abut against the forward head of the cylinder as heretofore described.

The plunger rod 44c is reduced in diameter at its outer end forming a shoulder 59c. A sleeve 56c is'swivelly carried by the reduced outer end of the plunger rod between

collars

138 and 139. The take-up pawl 430 is pivoted to the swivel sleeve 560 at 60c and has a tooth 61c 7 141 and 142 are divided in order to permit the take-up pawl 43c to move freely back and forth between the same.

The springs 47c and 47d normally hold the parts in the full line position shown in Figure 17. When air is introduced to the left end of the cylinder 45c the springs are compressed while the parts are moving to the dotted line position in order to enable the take-up pawl tooth 61c to engage an upper tooth 420 of the rack bar 33c.

When the air pressure is evacuated from the cylinder 450 the springs 47c and 47d again become active to shift the parts including the take-up pawl 43c rearwardly or to the left thus moving the rack bar 330 in the same direction and taking up slack in the brake rigging which is connected to the rack bar through the floating lever. In the final rearward position the kickout finger 65c has engaged the forward cylinder head and rotated the pawl 43c about the pivot pin 600 to lift the pawl tooth 61c out of engagement with the upper rack bar teeth 420, thus permitting the rack bar to return in the forward direction insofar as permitted by the rotary pawl 36c. The

lugs

141 and 142 cooperate with the kick-out finger 650 to lift the take-up pawl out of engagement with the rack bar 330. In view of the length of the take-up pawl 430 it may be advisable to employ some such devices as the

lugs

141 and 142 near the free end of the pawl to assist in raising the same. The kick-out finger 65c and the disengaging lugs 141 and 142 act to raise the knob or boss 140 up against the lower part of the wall of the cylinder 450 which will prevent chattering or undesirable movement of the take-up pawl 43c.

This device according to Figure 17 provides a compact short form of slack adjuster in which the rack bar, housing slot 63c, take-up pawl 43c and the engine cylinder 45c extend one above another vertically and, even though the cylinder 450 is extremely short axially, the housing is longer only to provide attachment at its ends to the car frame directly or through appropriate brackets. The throw of movement of the parts may also be so regulated as to be reduced to a minimum in this form of device.

Referring more particularly to Figure 18, the same is a modification of the device as shown in Figures 1 and 2, in that the pawl 43d is provided with an upwardly extending boss or elbow 140d adapted to engage the cylinder when the kick-out finger 65d raises the pawl 43d out of engagement with the rack bar. Such arrangement makes for a tight condition of all the parts.

Referring more particularly to Figure 19, a further modification is shown in which the swivel connection of the take-up pawl to the plunger rod is dispensed with and only the pivotal connection 60a is employed. In this instance, the take-up pawl 43a remains at all times within a portion in the top housing slot 68a so as to be in confinement of the side walls of the slot 681: which will thus prevent casual or accidental rotation of the take-up pawl 43a or of its plunger rod 44b. The take-up pawl 43a may be movably mounted in a cut-away portion 127 of the enlarged end 128 of the plunger rod 44b.

Referring more particularly to Figure 21, a modified form of plunger stop is employed involving a sleeve 129 projecting forwardly from the plunger 46b with the forward free end of the sleeve 129 adapted to engage the inner end of the forward cylinder head 48a. The sleeve 129 slides freely within the convolutions of the spring helix 47a and the length of the sleeve 129 is so calculated that the same will abut the forward cylinder head 43a before the spring 47a goes solid, or, in other words, before the spring 470 is so compressed that its convolu tions completely close. In this instance, it is unnecessary to provide any such stop shoulder on the inside wall of the cylinder 45a as is shown at 86 in Figures and 6.

Referring more particularly to Figures 22, 23 and 24, one of the handles or projections 41 of the rotary pawl 36 is connected to a cable having a vertical run from the handle 41 upwardly to a sheave 131 rotatably mounted in a bracket 132 secured to and depending from the floor support 133 or other portion of the car framework. A horizontal run 134 of the cable extends from the sheave 131 over to the bottom flange 135 of the side sill 136 of the car. The free end of the cable may be made captive to such flange 135 by a rivet or other fastening 137, one or more washers being employed if desired. In the use of the device, referring more particularly to Figures 1 to 13, inclusive, so long as the piston in the brake cylinder 87 does not exceed a predetermined degree of linear travel, the application of the brakes will proceed in an orderly conventional manner without interference from or any movement on the part of the im proved regulator which is included in the brake rigging system.

In Figure 13, the floating lever is shown in full lines in an initial position with new brake shoes. These brake shoes 95, 96, and 105, 106 have a predetermined initial clearance with respect to their

truck wheels

97, 98, 167, 108. As wear occurs in the brake shoes and the clearance tends to increase accompanied by an undue increase in the length of travel of the piston in the brake cylinder 87, such piston will uncover the port to the air conduit 50, thus placing the regulator cylinder 45 in communication with the pressure of the brake system as applied to the brake cylinder 37. Such pressure will move the regulator piston 46 from the position of Figure 5 to that of Figure 6, compressing the spring or springs 47 and shifting the take-up pawl 43 to a forward position where it will engage a tooth of the top teeth 42 of the rack bar 33.

It will be noted that any slack take-up is not performed during the application of the brakes. However, as soon as the brakes are released the air pressure in the brake cylinder 87 and, consequently, also in the regulator 45 will fall releasing the piston 46 to the action of the spring or springs 47. The spring 47 will then move the piston 46 from the position of Figure 6 back to that of Figure 5. In so doing it will move the take-up pawl 43 from the dotted line position of Figure 5 to the full line position of the same figure. In executing this movement the take-up pawl 43 pulls the rack bar 33 to the left or rearwardly on a slack take-up stroke at the end of which the take-up pawl 43 is disengaged from the rack bar 33 by the kick-out finger or member 65.

Figure 7 shows an intermediate position of the take-up pawl 43 nearing the end of its slack take-up stroke. This figure shows that the take-up stroke of the rack bar has moved the rotary pawl 36 from the position of Figure 5 to that of Figure 7. In this Figure 7 only one tooth, the initial tooth 37, is in engagement with the bottom tooth rack of the rack bar 33. Due to this fact and due to the inclination of the ratchet teeth 35, the rack bar 33 may continue to move to the left or rearwardly on to the end of its slack take-up stroke. In so doing the teeth 35 of the rack bar 33 and the initial tooth 37 of the rotary pawl 36 member together in a pawl and ratchet operation in which the inclined teeth 35 of the rack bar will freely move and click over the initial tooth 37 of the pawl, rotating the pawl counter-clockwise as each tooth 35 passes thereover. As soon as the peak of a tooth 35 passes the initial pawl 37 in the position of Figure 7, the offset mass 49 of the pawl which is now to the right side of the rotary pawl 36 will counter rotate such pawl 36 in a clockwise direction through a small angular distance until the initial tooth 37 enters the space forwardly of the next successive tooth 35.

In this way the rotary pawl 36 does not interfere with the sliding movement of the rack bar 33 on its slack take-up stroke, hence the rack bar 33 may take up successive new positions with respect to the rotary pawl 36 as wear takes place in the brake shoes and as that wear is compensated for by the automatic slack take-up action of the improved slack adjuster. As wear takes place increasingly in the brake shoes the rack bar 33 will be moved progressively to the left or rearwardly until the rack bar arrives at a maximum rearward position which marks the maximum wear in the brake shoes.

It will thus be seen that the weighted otfset 40, in the position of Figure 7, biases the initial tooth 37 at least to a meshing engagement with the bottom rack teeth 35. At the end of each slack take-up stroke, the take-up'pawl 43 is released automatically from-the rack bar, 33. As soon as this occurs the weightand the tension in the brake rigging will tend to pull the floating member 100 back In doing so the rack bar 33. will be pulled back to the right or forwardly on a slackening or lost motion stroke.- The length 'of this stroke is dependent upon the rotary pawl 36 as the olfset portion 40 of this pawl forms the stop, as shown. in Figure 5.. Inother words, when the oflset portion 40 of the pawl:36 is rotated clockwise from the position of Figure 7 to that of Figure 5, theoifset portion 40 will strike the rack bar 33 and will 'act as .a stop arresting the further forward. or right hand movement of the rack bar 33. 'The tangential teeth 39 of the rotary pawl 36 interlocking with the bottom rack bar teeth 35 will arrest further the right hand movement or slackening stroke of the rack bar 33. Thus as the rack bar 33 takes up a new position with respect to the rotary pawl 36, such rack bar 33 will beprevented from returning to the same position to the right and thus slack is automatically taken up in the brake rigging as it occurs.

The device is made sensitive and responsive to changes beyond normal in the linear travel of the piston in the brake cylinder so that the clearance between the wheels and the brake shoes isautomatically and promptly adjusted as changes in this clearance tend to occur through wear of the brake shoes, such increases in clearance adversely affecting the ideal limits of travel of the piston in the brake cylinder.

Referring to Figure 8, it will be seen that through the handles 41 the rotary pawl 36 may be rotated counterclockwise to a position where all of the teeth of the rotary pawl are disengaged from the bottom rack bar teeth 35. In this position the blanktoothl'ess portion of the rotary pawl 36 is brought opposite the rack bar 33. Thus the rack bar may be shifted all the way to the right or forward position so as to create full slack in the brake rigging for the purpose of application of new brake shoes.

The handle 109 of Figure 13 or 109a of Figure 14 or the handle 118 ofFigure 15 may bowed to shift the rack bar 33 on its slack take-up stroke. These levers extend to the side of the car so that they may be manually operated without entering between the rails. In the same way, according to Figures 22, 23 and 24, one hand may be placed on the cable 134 a'short distance. inwardly '10 to the position generally shown in full lines in Figure 13.

10 ceived through this divided end and the pin 34a passes through a perforation in the floating lever 100. The pin slides in the slots 290. The arrangement is such as to permit the pin 342 to slide from the full line position of Figure 25 to the dotted line position before such pin 34s engages the forward shoulders 201 of the rack bar 33e. Thus when the handle 1499 of the floating lever 100 is grasped and pulled rearwardly the pin 34e will move in the first instance through the slots 290 Without entraining the rack bar 33e. When the pin 34e engages the shoulders 201 the rack bar 33e will then be compelled to move rearwardly with the floating lever 100 on a slack take-up stroke. This arrangement will prevent the hand operation from limiting the brake shoes to a short clearance position from the car wheels which would result in undesirable short travel of the piston in the brake cylinder.

it will also be noted from Figures 25-29 that in this form of the invention there is eliminated from the rotary pawl 36e the circumferential or sector teeth 38, and the initial tooth 37:: is rearranged so that it is immediately adjacent the olfset portion 402. In other words the tangential teeth 3% are immediately rearward of this initial or ratchet tooth 37c. The rotary pawl 362 is further modified in that forwardly of the initial or ratchet tooth 37e the rotary pawl is blank and toothless. Such rotary pawl 36e further departs from the rotary pawl heretofore described in that a weighted handle 202 projects from the rotary pawl body substantially opposite from the otiset portion tile. Whereas in previous forms the offset portion was depended upon, as in Figure 7, to urge the initial tooth into engagement with the lower rack bar teeth, the weighted handle 202 now biases the initial of the flange 135 and a cable pushed upwardly to raise the rotary pawl to the position of Figure 8, while the other hand grasps the floating lever handle 1'09, 109a or 118 to move the lever andthe rack bar back to starting position.

The length of the stroke of the take-up pawl 43 on its I rearward or slack take-up movement in relation to the angular distance covering the toothed portion of the rotary pawl 36 may be such that one tooth 35 will be taken up at each stroke of the rack bar 33. However, it will be obvious that a greater length of the rack bar may be taken up at each operation withre'spect to the rotary pawl 36 and such length may also be dependent on the size of the teeth and the teeth spaces between the rotary pawl 36 and the rack bar 33.

Referring more particularly to Figures 25-29,. an important simplified shortened form of the invention is illustrated in which the rack bar and take-up pawl have a short stroke.

It will be noted that in this form of the invention a lost-motion slot 200 is provided-in the 'divitl'edforward end of the rack bar 33c. The floatingleverlllflis' retooth 3% into engagement with the lower rack bar teeth 35c of the rack bar 33a.

The handle 202 is provided with a recess 300 for receiving a spring 361 the inner end .of which engages the bottom of the recess 360. as a fixed stop. The spring surrounds a plunger rod 302 having an enlarged prefer; ably rounded head 303 against which the outer end of the spring engages for the purpose of normally projecting the rod 362 and the head 303 to the position shown in Figure 25 in which a cotter or other key 304 in the rod 302 engages the handle 202 to act as a stop to restrict the expansive action of the spring.

In operation, when compressed air enters the head 492 of the slack adjuster engine due to long travel of the brake piston, the slack adjuster engine piston 46a will be moved forwardly compressing the spring 472 and moving the stop 53 against the forward cylinder head 48a. It will be noted, particularly from Figure 28, that the slack adjuster engine 4512 is very much shortened in axial length and that the stroke of the engine piston 46a and the take-up pawl 43a is comparatively short. The pawl 43e is thus moved to forward potential position and engaged with a tooth 42e of the rack bar 331;. When the air pressure in the rear end of the engine cylinder 45c falls, the spring 47e expands and drives the piston 46e rearwardly carrying with it the take-up pawl 43e and the rack bar 33e. Due to the fact that the Weight and tension in the brake rigging will maintain the pin 34e against the forward ends of the lost-motion slots 260', the automatic operation involving. the rearward slack take-up stroke of the rack bar 33e will correspondingly move the floating lever and take-up slack in the rigging with a minimum of lost motion. 7

When the take-up pawl 43a drives the rack bar 33; rearwardly on a slack take-up stroke, the rotary pawl 36e rotates counter clockwise to promptly withdraw the oil'- set'stop 40e and the tangential locking teeth 39e from engagement with the lower rack bar teeth 35c, but the weighted arm 202 will constantly urge the initial tooth 37e into engagement with the lower rack bar teeth 356. These teeth have rear abrupt walls and forward inclined walls so that as the rack bar'33e is'driven rearwardly the inclined walls of the teeth 35e and the initial tooth 372 will slide upon one another in a pawl and ratchet operation permitting of such rearward movement of the rack bar but preserving the meshing of the tooth 37a with the teeth 35c so that any attempt at forward movement of the rack bar 33a will entrain the pawl 36:: to rotate therewith in a clockwise manner, thus promptly bringing the offset 400 against the rack bar. The offset thus constitutes a stop to arrest the forward clockwise rotary movement of the rotary pawl 352. Due to the engagement of the initial or ratchet tooth 37a of the rotary pawl with the lower teeth 35s the rack bar will thereupon be arrested in forward movement.

For purposes of strength and to take the strain off the initial or ratchet tooth 37c it is desirable also to employ one'or more tangential teeth 39a to interlock with the lower rack bar teeth 35s to assist in this locking operation. Due to the fact that there is a blank space on the periphery of the rotary pawl 36c immediately forward of the initial or ratchet tooth 37e and due to the fact that the offset 4% and tangential teeth 3%, if any, are immediately rearward of the initial or ratchet tooth 37e the pawl 362 will have a minimum of angular movements so that the rack bar 33c will be early arrested in any forward movement.

In the form of invention shown in Figures 2529, in the position in which it occupies in Figure 25 the initial or ratchet tooth 37 of the rotary pawl 36a is disposed on the arc of the circle on which the rotary pawl 36s rotates and such tooth 37a is near the top of such circle and at the right or forward of a vertical center line passing through the rotary axis of the rotary pawl 360 when the pawl is in its locked position. Due to this position the initial or ratchet tooth 372, compared with the form of pawl shown in Figures 5 and 7, has a shorter arc of rotation with a decreased amount of linear rack bar movement.

7 The engine piston Me has a shorter stroke compared with other forms of the invention, which permits an automatic take-up on the rack bar 33a when the brake cylinder piston is only partially released after it has exceeded its required linear travel when the brake application was made.

When the rotary pawl See is in its locked position (Fig. the spring 361 is at its free height with the plunger button or head 3&3 positioned to contact with the bottom wall of the rack bar housing when the pawl is rotated toward its release position as shown in Figures 28 and 29.

In these latter Figures 28 and 29 the spring 301 has been compressed so that it affords a quick kick-back of the initial or ratchet tooth 37e toward the rack bar teeth e.

When the pawl 36; is rotated toward its locked position or the initial or ratchet tooth 37c passes the vertical cenfor line, the tangential teeth 3% come in contact with the rack bar teeth 35a to arrest forward movement of the rack bar 330. The kick-back head 303 is then out of contact with the bottom wall of the housing.

When the engine spring 470 moves the take-up pawl 430 through to the end of its take-up stroke the kicloout finger 65e will release the take-up pawl 43c from the top teeth 420 of the rack bar 33e, thus releasing the rack bar for forward movement under the weight and tension of the brake rigging. The rack bar 53a is permitted a decreased forward movement dependent upon the amount of angular clockwise movement of the rotary pawl 36? sufficient to bring the offset 4% and the tangential teeth against the rack bar 330. This forward movement of the rack bar 33e consequent upon a rearward slack take-up stroke, restores normal slack to the rigging and many therefore be called a lost-motion. This lost-motion is in the rotary pawl 36:: by which the arrangement of its teeth and offset portions limits this forward travel of the rack bar 33c.

The rack bar 33e has the lost motion slot 200 to supplement the lost-motion in the pawl 366 to provide a selected amount of slack take-up in the foundation brake rigging when thebrake is adjusted manually by the movement of the levers 109, 109a and 118 of Figure 13, 14 and 15. When the brake is adjusted manually by the floating lever, the pin 34e, Figure 25, will move to the dotted line position before entraining the rack bar to rotate the pawl 36a to its released position, at which point any additional movement of the floating lever 100, 109 in the slack takeup direction would adjust the brake to the same linear selected travel provided by the automatic take-up when the brake cylinder port is uncovered to permit brake cylinder air to flow to the automatic slack take-up cylinder 45e.

In the first form of the invention, inasmuch as there is no lost-motion slot such as 200, in the rack bar, the rotation of the rotary pawl 36 from the position of Figure 5 to that Figure 7 is the same'with both manual and automatic operations. In both forms of the invention, with the manual operation the brake shoes are pulled against the wheels before any excess slack is taken up in the rack bar.

In the first form of the invention, with the automatic take-up, after an application of the brakes and excess linear brake piston travel the pull of the take-up pawl 43 (Figures 5, 6 and 7) on the rack bar and floating lever, holds the brake shoes close to the wheels until the brake cylinder piston reaches its extreme release position before any slack is taken up at the rack bar.

In the second form of the invention (Figures 25-29) with the automatic take-up, the pull of the take-up pawl 43a on the rack bar 33e and floating lever 100, holds the brake shoes close to the wheels after an application of the brakes and excess linear piston travel until the brake cylinder piston has moved towards release position a distance equal to the linear movement of the rack bar 33c corresponding to the rotation of the rotary pawl 36a; or in other words the brake cylinder piston only moves through a portion of its release stroke whereupon slack is taken up at the rack bar.

Where cars are set out on cleaning tracks, where brake shoes are frequently applied, in preparation for loading or on other minor repair tracks where air for charging the air brake system is not available, the manual adjustment of brakes to the correct linear piston travel is a necessary function of a brake slack adjuster.

What I claim is:

1. A slack adjuster for the foundation brake rigging of railroad cars comprising a movable rack bar adapted to be coupled to the brake rigging, a take-up pawl membering with the rack bar to move the latter in a slack take-up direction, a motor connected to drive said pawl, means for disengaging the take-up pawl from the rack bar on the completion of the take-up stroke of the rack bar to release the rack bar for return movement in a rigging-slackening direction, a rotary pawl membering with the rack bar having a blank toothless portion rotated opposite the rack bar on the take-up stroke of the rack bar to permit the rack bar to shift relatively to the rotary pawl, means on said rotary pawl for permitting the return movement of the rack bar in its rigging-slackening direction after the take-up pawl has been disengaged from the rack bar, said rotary pawl having an offset toothed portion displaced angularly from the blank portion in position to abut and interlock with the rack bar to. arrest the movement of the rack bar and terminate its slackening stroke.

2. A slack adjuster for the foundation brake rigging of railroad cars comprising a movable rack bar adapted to be coupled to the brake rigging, a take-up pawl membering with the rack bar to move the latter in a slack take-up direction, a motor connected to drive said pawl, means for controlling said motor to move the take-up pawl and rack bar only subsequent to an application of the brakes, means for disengaging the take-up pawl from the rack bar on the completion of the take-up stroke of aas sze the. rack bar. to. release. therackbar. for.. return move.-

ment in a rigging-slackening, direction, a..no tarlyl pawl memberihg with. the. rack having. a blank. toothless portion rotated opposite the rack bar. on thetake-up stroke of, the. rack bar. to. permit. the; rack .bar. to shift relatively to the. rotary pawl, and havingrneans thereon for permitting. the return movementof the. rack bar in its riggingeslackening direction untilv the. normal rigging sl'ackhas heenrestorei. said rotary. pawlhaving an. olfset toothed. portion displacedLangularly from: the blank portion. in. position to abut. and. interlock with the rack. bar to arrest the..movement of. the. r-acklbar. and terminate its. slackening.stroke.-

3. An. automatic slack adjuster for the foundation brake rigging. of railroad cars. comprising a. movable limiting. the movement of themovable member. in its rigging-slackening.direction.. y V y 4. A slack. adjuster forithegfoundation. brake rigging of railroad. cars comprising a. movable toothed. member. adapted to be coupledto. the brake. rigging, a.,take'-up element engaging said, member. to. move the. latter. in a slack take-up. direction, a. motor. connectedntodrive said elementcomprising: compressedain means. connected to V for automatically disengaging the. take-up element from the. member. on the. completion .of.; the. take-11p strokev oh the. member to release the..memher for returnmovement M at railroad cars. comprising amovable. .rack bar. adapted to. be-coupled'to the brake .rigginglatake-up pawl ment-a bering. with the rack bar to. move ,the-..'latter in,a. slack take-updirection, means connected to drive said pawl on its. take-up stroke a swivel connection between said drive meansv and said. take-up... pawl means. for, disen gaging; the. take-up pawl fromthe. rack bar-on the com.- pletion of the. take-up strokeof, the, rackbarto. release therackbar for return movement arigging-slackening direction, a rotary. pawl membering with, therackbar having a. blank toothless..portionrotated opposite. the

rack. bar. onthe. takeaup stroke. .of the 'rackbar. to. permit the rack bar to shift. relatively to. the rotary; pawl; said rotary pawl.havingan. otfset..,toothed portion displaced angularly' from the. blank portion. in. position to .abntan'd interlock with.theQ rack bar toarrest the movement of therackbarand terminate it's.slackening. stroke.

7.. A slackadjusterfor the. foundation brake: rigging of railroad cars comprising a movable rackbar adapted to be coupled to the brakeri'gging, a. take-up pawl engaging the rackbar. to movethe latterin a: slack take-up direction, a motor connected .to drive said pawl comprisingareciproeating and rotary plunger rod, a sleeve; swivelly: mounted to. said rod, said. take-up. pawlv pivoted. to said. sleeve in offset relation to said/rod toward. saidxrackv bar, akickout finger fixedly mountedwithpai'd pawl, and fixed abutment incthe' path of said finger for-trippingthetake up V pawl out. of engagement with said. rack bar, a rotary in. 'a. rigging-slackening direction, a. rotary. .member. en-' gaging with said vtoothedIniember havinga, blank toothless. portion rotated opposite. the toothed member on the.

takerup stroke of the toothed; member to permit the toothed'member. to shift relativelytothe' rotarymernber, saidrotary member having. an:' oifset toothed. ortion displaced angularly from the. blank portion in position to abut and interlockwiththe toothedmember. to arrest the movement of the toothed. member andterminateits slackening stroke. v

5.1 A slack adjuster for the foundation-brake rigging of railroad cars comprising. awmovable rack has adapted to be coupled to the brake. rigging, a take-up pawl membei ing with the rack bar to. move the latter in'a slack takeI-updirection, a motonconnectedtodrive said pawl, a kick-out member connected .to said take-up pawl, an abutment positioned to engage said kick-out member on the completion-of the-takeeup stroke of thearack bar to withdraw the. take-up. pawl from. engagement from the rack bar whereby to release the rack bar for return moyement in a--'rigging-slackening direction incident to the weight of the rigging; arotaryp'awl having an initial tooth membering with-therack bar at least during the end of the' slack take-upstroke 'and having a blank toothless portion rotatedopposite'the rackbar' on the take-up stroke of the rack bar'to" permit the rack bar' to; shift the pawlifrom the'rack bar to: permit" the takingup of abut and interlockwith the rack bar to arrest the movei pawl engaging, the. rack: her. having ablank toothless portion :rotated" oppositethe rack bar 011-. the. take-up stroke ofqthe rack-bar to permit the rack. bar to: shiftrelatively to. the rotary pawl, said rotary, pawl having an offset toothed portion displaced angularly. from the blank. p0rtion in; position tonabut andinterlockwith .thevrackrbar to.arr.est .the movement-of the; rack bar and. terminate. its slackening; stroke.

8.. A slackadjuster. for the; found atiorrbrake rigging of railroad cars comprising a movable rack baradapted to be coupled: to. the. brake-rigging, a. take-up pawl engaging the rack bar tomove thelatter in --a slack take-.np direction, a motor connected, to drive. saidpawl, means for disengaging. thetake-up pawlfromtherack ,bar on the. c'ompletionofthe take-upstroke ofthe rackbar. to release the rack. bar for. returnsmovement in at rigging.- slackeningdirection, a rotary pawl engaging the. rack bar having: a blank: toothlessportion. rotated, opposite the rack. bar on the. take-up stroke ofthe rackbar to-permit the rack bar to. shift relatively to the rotary pawl, said rotary pawl having an offsettooth'edportion. displaced angularly from the blank portionin position to abut and interlock with the rack bar tozarrest. the movementof the'rack bar and terminate its slackeningstroke, a. handle projecting laterally from the offset portion of said rotary pawl to lift the; pawl to a positionwhere the. blank toothlessportionis opposite the rack bar, and meansconnected: to said, handle. andextendingto the side of the car forlifting of. saidhandle;

9. A. slack adjuster for the foundation brakerigging of railroad cars, comprising: a housing having horizontal. andrelationtofthe rack bar, a pawl membering-withfthe rack bar andhaving means thereon: for. permitting-rotation of the pawl' apredetermined distance: prior to release of slack in *thetbrjake rigging when th'e-leyer is moved. in one direction and permittingmovernent of the pawl a predetermined distance in the opposite direction to-locked position, when the lever isrnoved in the opposite. direction. '1.0.-'A- slack adjuster tori thefoundati'on; brake; rigging of railroad cars, comprising-a housing having vertical and horizontal slots, a lever projecting through the horizontal slots, a rack bar movableinthe housing and attached to the lever, a pawl engaging the rack bar, the housing hav- 15 7 ing elongated trunnion bearings adapted to receive the pawl permitting linear movement of the pawl in relation to the housing when the pawl is rotated toward release position.

11. A slack adjuster for the foundation brake rigging of railway cars comprising a rack bar having means adapted to attach it to the brake rigging, means for moving the rack bar in a rearward direction on'a slack take-up stroke, a rotary pawl membering with the rack bar in a pawl and ratchet operation to permit of rearward movement of the rack bar on its slack take-up stroke, trunnions for said rotary pawl, and fixed bearings in which said trunnions are fitted to rotate, said bearings being larger than the diameter of said trunnions to permit of looseness and play of the trunnions in the bearings and consequently a lost motion between the rack bar and the rotary pawl.

12. A slack adjuster for the foundation brake rigging of railroad cars comprising a movable rack bar adapted to be coupled to the brake rigging, a take-up pawl membering with the rack bar to move the latter in a slack take-up direction, means for disengaging the take-up pawl from the rack bar on the completion of the take-up stroke of the rack bar to release the rack bar for return movement in a rigging-slackening direction, a rotary pawl having an initial tooth membering with the rack bar at least during the end of the slack take-up stroke and having a blank toothless portion rotated opposite the rack bar on the take-up stroke of the rack bar to permit the rack bar to shift relatively to the rotary pawl, said rotary pawl having an off-set toothed portion displaced angula-rly from the initial tooth and from the blank portion in position to abut and interlock with the rack bar to arrest the movement of the rack bar and terminate its slackening stroke, and a motor for driving said take-up pawl on its slack take-up stroke and for moving said means firmly against a part of the slack adjuster to hold the take-up pawl against vibratory motion when disengaged from the rack bar.

13. An automatic slack adjuster for the foundation brake rigging of railway cars comprising a rack bar adapted to be coupled with a lost motion free connection to the brake rigging, means for automatically moving the rack bar in slack take-up direction, a rotary pawl having a ratchet tooth membering with the rack bar in a pawl and ratchet operation to permit movement of the rack bar in a slack adjusting direction while retaining the engagement of the ratchet tooth with the rack bar, and a stop carried rotatably by said rotary pawl moved away from the rack bar by the rack bar when the rack bar is moved in the slack take-up direction and moved by the,

brake rigging of railway cars comprising a rack bar, a

lost-motion free connection at the forward end portion of the rack bar for attachment to the brake rigging, means to automatically move the rack bar rearwardly in a slack take-up stroke, means for permitting unlimited rearward movement of the rack bar on its slack take-up stroke and for arresting the forward slack restoring movement of the rack bar after the normal slack has been restored to the brake rigging comprising a rotary pawl mounted adjacent the rack bar and having a ratchet tooth membering with said rack bar, said rotary pawl having a blank toothless portion forwardly of said ratchet tooth and an ofiset portion immediately rearward of said ratchet tooth adapted to engage the rack bar as a stop to prevent forward rotation of said pawl, at least one tangential tooth on said offset portion adapted to engage a corresponding tooth of the rack bar to aid in locking the rack bar against forward movement and a counter weight on the rotary pawl projecting oppositely from said otfset portion to urge the ratchet tooth against said rack bar.

15. An automatic slack adjuster for the foundation brake rigging of railway cars comprising a rack bar adapted to be connected to the brake rigging, automatic means to shift the rack bar step by step on a rearward slack take-up movement, and holding means cooperating with the rack bar and operatively connected with and moved by the rack bar on the slack take-up movement of the rack bar to a position in which it permits the rack bar to continue its slack take-up movement and permitting a forward movement of the rack bar sufiicient to restore normal slack to the brake rigging, the forward movement of the rack bar moving said holding means to a position in which the holding means arrests further forward movement of the rack bar in its brake rigging slack restoring movement.

16. A slack adjuster for the foundation brake rigging of railroad cars comprising a movable rack bar adapted to be coupled to the brake rigging and having a series of take-up teeth on one edge thereof and a series of holding teeth on the opposite edge thereof, the major portions of the two series of teeth being in overlapping relation, a take-up pawl engaging the take-up teeth tomove the rack bar in a slack take-up direction, means to drive said pawl, means for disengaging the take-up pawl from the take-up teeth on the completion of the take-up stroke of the rack bar to release the rack bar for return movement in a rigging-slackening direction, a rotary holding pawl, engaging the holding teeth and having a blank toothless portion rotated opposite the rack bar on the take-up stroke of the rack bar to permit the rack bar to shift relatively to the rotary pawl, said rotary pawl having an offset portion displaced angularly from the blank portion in position to abut and interlock with the rack bar to arrest the movement of the rack bar and terminate its slackening stroke.

17. A slack adjuster for the foundation brake rigging of railroad cars comprising a movable rack bar adapted to be coupled to the brake rigging, a take-up pawl membering with the rack bar to move the latter in a slack take-up direction, means to drive said pawl, means for withdrawing said pawl from engagement with the rack bar comprising a kick-out finger on said pawl and an abutment positioned to engage the underface of said finger to support said finger and pawl to positively maintain the pawl out of engagement with the rack bar, and holding means cooperating with the rack bar and operativcly connected with and moved by the rack bar on the slack take-up movement of the rack bar to a position in which it permits the rack bar to continue its slack take-up movement and permitting movement of the rack bar in the opposite direction a sufiicient distance to restore normal slack to the brake rigging, the slack restoring movement of the rack bar moving the holding means to a position in which the holding means arrests further movement of the rack bar in its brake rigging slack restoring movement.

References Cited the file of this patent UNITED STATES PATENTS OBoyle Apr. 20, 1954