US2620681A - Hand brake for railway cars - Google Patents

Description

Dec. 9, 1952 F. E. BRETZ, JR

HAND BRAKE FOR RAILWAY CARS s She ets-Sheet 1 Filed Aug. 5, 1950 IN VEN TOR.

Dec. 9, 1952 F. E. BRETZ, JR 2,620,681

HAND BRAKE FOR RAILWAY CARS Filed Aug. 5, 1950 v 3 Sheets-Sheet 3 IN VEN TOR.

v Trim/z lfirey, Jn

Patented Dec. 9,1 952 UNITED STATES PATENT OFFICE HAND BRAKE FOR RAILWAY CARS Frank E. Bretz, Jr., Oak Park, Ill., assignor to Ajax-Consolidated Company, Chicago, 111., a corporation of Illinois Application August 5, 1950, Serial No. 177,803

7 Claims.

This invention relates, generally, to brakes and it has particular relation to hand brake operating mechanisms for railway cars.

Among the objects of this invention are: To provide for uncoupling the hand wheel which is used to set the brakes from the brake rigging when the brakes are manually released so that the hand wheel does not turn or spin backward as an incident to such release; to accomplish such uncoupling action by means of a clutch; to employ as the shiftable element of the clutch a member which encounters a minimum of friction in its operation; to locate the clutch between the pinion which drives the main gear wheel attached to the chain winding drum and the ratchet wheel which holds the brakes set; to mount the ratchet wheel so that it can be shifted longitudinally to disengage the clutch while it is held by a pawl against rotation but is movable transversely of the pawl; to permit a graduated release of the brakes as well as a substantially instantaneous release thereof; and to accomplish the graduated release by biasing the pawl which prevents reverse rotation of the ratchet wheel away from engagement therewith.

Other objects of this invention will, in part, be obvious and in part appear hereinafter.

This invention is disclosed in the embodiment thereof shown in the accompanying drawings and it comprises the features of construction, combination of elements and arrangements of parts which will be exemplified in the construction hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature andscope of this invention, reference can be had to the following detailed description, taken together with the accompanying drawings, in which:

Figure 1 is a front view, at a reduced scale, showing the housing for the hand brake mechanism in which the present invention is embodied, portions of the hand wheel being broken away in order to illustrate more clearly details of construction of the case and the location of the trip handle;

Figure 2 is a view, at an enlarged scale, of the case and operating mechanism, certain parts being broken away and others being shown in section to illustrate more clearly the details of construction;

Figure 3 is a detail sectional view taken generally along the line 33 of Figure 2, the trip handle and pawl being omitted;

Figure 4 is a detail sectional view taken generally along the line 4-4 of Figure 3;

Figure 5 is a view in end elevation of the pinion;

Figure 6 is a detail sectional view taken generally along the line 66 of Figure 5;

Figure '7 is a view in elevation of the opposite end of the pinion from that shown in Figure 5;

Figure 8 is a view, in end elevation, of the ratchet wheel which has a large diameter relative to the diameter of the pinion shown in Figures 5, 6, and 7;

Figure 9 is a detail sectional view taken generally along the line 99 of Figure 8;

Figure 10 is a view, in side elevation, of the trip handle shaft to which are secured the hold down arm and the semicircular spiral cam for moving the ratchet wheel toward and away from the pinion;

Figure 11 is a view, in end elevation, of the trip handle shaft and parts attached thereto illustrated in Figure 10; and

Figure 12 is a view, in side elevation, of a modified form of pawl which is counterweighted to swing away from the ratchet wheel.

Referring now particularly to Figure 1 of the drawings it will be observed that the reference character [0 designates, generally, a hand brake mechanism in which the present invention is embodied. The hand brake mechanism Illincludes a case which is indicated, generally, at II. The case ll includes a hollow cover l2, Figure 3, which has an outwardly extending flange. I3 that overlies a back plate I4. The flange l3 and underlying portion of the back plate M are employed for mounting the hand brake mechanism In on the side or end of a railway car as will be understood readily.

Again referring to Figure 1 it will be observed that a hand wheel [5 is carried on the front side of the case II, in a manner to be described, and that a trip handle I6 is mounted thereabove. Its function will be described hereinafter. The hand brake mechanism I0 is connected to the brake rigging of the railway car by means of a chain n.

Referring now particularly to Figures 2 and 3 of the drawings, it will be noted that the chain I1 is connected by a pin l9 to a chain winding drum 20 which is mounted for rotation about a stationary shaft 2| that extends between and is supported by the cover [2 and the back plate I 4. Formed integrally with the chain winding drum 20 is a main gear wheel 22 having gear teeth 23 that are arranged to have driving engagement with gear teeth 2d of a pinion 25 the details of construction of which are shown more clearly in Figures 5, 6 and 7.

It will be observed that the pinion 25 has a relatively small diameter as compared to the diameter of the main gear wheel 22. The pinion 25 is rotatably and non-slidably mounted on a pinion bearing surface 26 of a hand wheel shaft if the axis of rotation of which is parallel to the axis of rotation of the chain winding drum 2% and main gear wheel 22. The hand wheel shaft 2? is rotatably mounted in the cover 52 by a bearing casting 28. At its rear end it is rotatably mounted in the back plate i i by a bearing bushing 29 which interfits with an inturned flange 3d of the back plate i i. Near its rear end the hand wheel shaft 2'! is provided with a split ring Si in a suitable groove against which a bearing sleeve 32 reacts. The bearing sleeve 32 has a press fit with the rear end of the hand wheel shaft 271 and is journaled in the bearing bushing The split ring 3! prevents longitudinal movement of the pinion 25 toward the rear end of the hand wheel shaft 2?.

It is desirable to disengage the pinion 2% from driving engagement with the hand wheel I so as to permit free reverse rotation of the chain winding drum 2&3 and main gear wheel 22 when the brakes are to be released without the accompaniment of reverse rotation of the hand Wheel 55. For this purpose a clutch, shown generally at 35, is employed, As shown in Figure 3 the clutch 35 is formed in part by a ratchet wheel 36, Figures 8 and 9, which has a diameter that is large as compared to the diameter of the pinion as. The ratchet wheel 35 is non-rotatably and slidably mounted by a ratchet bushing 3?, Figure 4, on a non-circular bearing surface 38 intermediate the ends of the hand wheel shaft 2?. As shown in Figure 4 the non-circular bearing surface includes a flat surface 39 which cooperates with the ratchet bushing 3'! and the correspondingly shaped opening through the ratchet wheel 3% to prevent relative rotation thereof while permitting relative longitudinal sliding movement.

Outward movement of the hand wheel shaft 2? is prevented by a radial flange id, Figure 3, which is located just inside the bearing casting 28.

The clutch 35, referred to hereinbefore as interconnecting the pinion 25' and the ratchet wheel 36, is formed by clutch teeth ll on the pinion 25, shown more clearly in Figures 6 and 7, and clutch teeth 42 on the ratchet wheel 36, shown more clearly in Figure 9. Provision is made, as hereinafter described, for sliding the ratchet wheel 36 along the non-circular bearing surface 3% of the hand wheel shaft 2? to engage or disengage the teeth 4! and 42 as required.

In order to hold the brakes set, the ratchet wheel 36 is provided with radially extending ratchet teeth 43, Figure 2, with which a ratchet pawl 44 cooperates. The ratchet pawl M is pivoted at 45 between the cover l2 and the back plate I l. The ratchet pawl e l is biased so as to swing by its own weight into engagement with the ratchet teeth 13. In some circumstances it may be desirable to force the ratchet pawl into engagement with the ratchet teeth at. For this purpose a hold down arm 5 5 is employed. As shown in Figure 2 this is arranged to cooperate with the back side of the ratchet pawl 3 5. The hold down arm 26 is formed integrally with a trip handle shaft M, Figures 3 and 10, which, as shown, is rockably mounted in the cover l2 and back plate i l. At its forward end the trip handle 4 shaft 4'! has a shank 5.3 which projects beyond the cover l2 and is arranged to receive the trip handle E6.

The trip handle it is arranged to effect the sliding movement of the ratchet wheel 36 for engaging and disengaging the clutch 35. For this purpose the ratchet Wheel 3%, Figures 8 and 9, is provided with a cam follower collar (it, that is formed integrally therewith. Cooperating with the cam follower collar 39 is a semicircular spiral cam 5e, Figures 10 and 11, that is formed integrally with the trip handle shaft ill. The cam 55 has a correspondingly shaped groove 5! that interfits with the radially projecting portion of the cam follower collar 49 so that, when the trip handle shaft ll is rocked from one position to the other the ratchet wheel 36 is moved toward or away from the pinion 25 to engage or disengage the clutch 35.

As shown in Figure 3 the hand wheel shaft 27 has a hand wheel attaching portion 55 for receiving the hand wheel 65. A look nut 5e secures the hand wheel H5 in position on the shaft 21.

In operation with the trip handle it in the position shown'in Figures 1 and 2 of the drawings where the hold down arm it engages the back side of the ratchet pawl 3 i, rotation of the hand wheel id in a clockwise direction will cause the chain ii to be wound on the chain winding drum 26. In this position of the trip handle Hi, the clutch 35 is engaged as illustrated in Figure 3. Accordingly, driving torque is transmitted from the hand wheel shaft 2'! through the non-circular bearing portion 38 of the shaft 2? to the ratchet wheel 35. By means of the clutch teeth 42 this torque is transferred to the clutch teeth ll formed integrally with the pinion 25. Since the pinion 25 is in direct engagement with the main gear wheel 22, rotation of the chain winding drum 20 is thus eifected. The ratchet pawl 44 holds the ratchet wheel 36 in any position to which it may be rotated by the hand wheel l5.

When the brakes are to be released, the trip handle it is swung in a clockwise direction as viewed in Figures 1 and 2 through substantially 186. While this movement shifts the hold down arm it out of engagement with the ratchet pawl it, the latter does not move out of engagement with the ratchet wheel 36, since, as described, it is biased by its own weight into such engagement. However, the movement of the trip handle it and corresponding movement of the trip handle shaft l'i shifts the position of the semicircular spiral cam 55 so as to eifecta corresponding shifting movement of the ratchet wheel 35. During this movement the ratchet pawl a l remains in engagement with the particular ratchet tooth 43 which it had previously engaged and there is relative sliding movement therebetween. Since the ratchet wheel 3% has a relatively large diameter as compared to the diameter of the pinion 25, this sliding movement between the ratchet pawl id and one of the ratchet teeth 2-3 takes place under minimum friction conditions. Also since the ratchet wheel 3% is mounted on the ratchet bushing 3? there is a minimum of friction between the latter and the non-circular bearing surface 36. When the trip handle it has been shifted through to its alternate position, the clutch teeth 32 have been moved out of engagement with the clutch teeth ll on the pinion 25. Since the latter no longer is restrained from rotation, the tension of the brake rigging applied through the chain ll causes the chain winding drum .28 to rotate in a reverse di- 5. rection. This is accompanied by a corresponding rotation of the main gear wheel 22 and a reverse rotation of the pinion 25. However, since the clutch 35 now is disengaged and further since the ratchet wheel 36 is prevented from rotating in a reverse direction by the ratchet pawl 44, the hand wheel 15 remains stationary. Hence it does not spin backward when the brakes are released.

When the brakes have been released to the desired extent, the trip handle [6 is rocked in a counterclockwise direction back to its original position shown in Figures 1 and 2. Theclutch 35 is reengaged and further reverse rotation of the pinion 25, gear wheel 22 and chain winding drum 20 is prevented.

In some instances it may be desired to provide for graduated release of the brakes. This means that the brakes are released under suchconditions that the clutch 35 remains engaged but the ratchet pawl 44 is moved out of engagement with the ratchet wheel 35. The brakeman then allows the hand wheel [5 to rotate in a reverse direction but under his control. In order to permit such operation the pawl 44 is provided, as shown in Figure 12, with a counterweight 59 which acts to bias the pawl 14 away from engagement with the teeth 43 of the ratchet wheel 36. Now when the trip handle I6 is swung from its position shown in Figures 1 and 2 in a clockwise direction through about 90, the hold down arm 46 is shifted out of engagement with the pawl 44 and the counterweight 59 rocks the pawl 44 out of engagement with one of the teeth 43 of the ratchet wheel 36 upon a slight rotation of the hand wheel 15 in the chain winding direction. However, at this position of the trip handle l5, the cam 58 has not as yet shifted the ratchetwheel 36 far enough to disengage the clutch 35. Accordingly, there is a direct mechanical connection between the hand wheel 15' and the chain winding drum 20. Thus the brakes can be released gradually under the direct control of the brakeman.

As before, where it is desired to release the brakes instantaneously, the trip handle Hi can be swung to the opposite side where the clutch 35 will be disengaged.

Since certain further changes can be made in the foregoing construction and different embodiments of the invention can be made without departing from the spirit and scope thereof, it is intended that all matter shown in the accompanying drawings and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is:

1. In a hand brake mechanism, the combination with a rotary chain winding drum and a main gear wheel of: a rotatable hand wheel shaft, a hand wheel fast on said hand wheel shaft, a pinion rotatably and non-slidably mounted on said hand wheel shaft and engaging said gear wheel, a ratchet wheel non-rotatably and slidably mounted on said hand wheel shaft and having a cam follower collar integral therewith, interengaging clutch means on said pinion and ratchet wheel, a pawl cooperating with said ratchet wheel to prevent reverse rotation thereof and slidable with respect to the teeth thereof when the same is shifted on said hand wheel shaft, a rockably mounted trip handle shaft, a trip handle fast on said trip handle shaft, and a cam fast on said trip handle shaft and cooperating with said cam follower collar for shifting said ratchet wheel along said hand wheel shaft to engage and disengage said clutch means, said cam being so positioned on said trip handle shaft that in one position of said trip handle said clutch means is engaged, and in another position of said trip handle said cam shifts said ratchet wheel on said hand wheel shaft relative to and held by said pawl to a position where said clutch means is disengaged whereupon the brakes are released while said hand wheel remains stationary.

2. In a hand brake mechanism, the combination with a, rotary chain winding drum and a main gear wheel of: a hand wheel shaft mounted for rotation about an axis parallel to the axis of rotation to said chain winding drum and main gear wheel, a hand wheel fast on said hand wheel shaft, a pinion rotatably and non-slidably mounted on said hand wheel shaft and engaging said gear wheel and having clutch teeth on the side facing said hand wheel, a ratchet wheel nonrotatably and slidably mounted on said hand wheel shaft and having clutch teeth on one side for engaging said clutch teeth on said pinion and a cam follower collar on the other side, a pawl biased into engagement with said ratchet wheel to prevent reverse rotation thereof and slidable with respect to the teeth thereof when the same is shifted on said hand wheel shaft, a rockably mounted trip handle shaft, a trip handle fast on said trip handle shaft, and a cam fast on said trip handle shaft and cooperating with said cam follower collar for shifting said ratchet wheel along said hand wheel shaft to engage and disengage said clutch teeth, said cam being so positioned on said trip handle shaft that in one position of said trip handle said clutch teeth are engaged, and in another position of said trip handle said cam shifts said ratchet wheel on said hand wheel shaft relative to and held by said pawl to a position where said clutch teeth are disengagedwhereupon the brakes are released while said hand wheel remains stationary,

3. In a hand brake mechanism, the combination with a rotary chain winding drum and a main ear wheel of: a hand wheel shaft mounted for rotation about an axis parallel to the axis of rotation of said chain winding drum and main gear wheel, a hand wheel fast on said hand wheel shaft, a pinion rotatably and non-slidably mounted on said hand wheel shaft and engaging said gear wheel and having clutch teeth on the side facing said hand wheel, a ratchet wheel non-rotatably and slidably mounted on said hand wheel shaft and having clutch teeth on one side for engaging said clutch teeth on said pinion and a cam follower collar on the other side, a pawl cooperating with said ratchet wheel to prevent reverse rotation thereof and slidable with respect to the teeth thereof when the same is shifted on said hand wheel shaft, a rockably mounted trip handle shaft, a trip handle fast on said trip han v dle shaft, a hold down arm on said trip handle shaft for engaging said pawl and holding it in engagement with the teeth of said ratchet wheel, and a cam fast on said trip handle shaft and cooperating with said cam follower collar for shifting said ratchet wheel along said hand wheel shaft to engage and disengage said clutch teeth, said hold down arm and cam being so related on said trip handle shaft that in one position of said trip handle said hold down arm engages said pawl and holds the same in engagement with said ratchet wheel while said clutch teeth are engaged, and in another position of said trip handle said hold down arm is disengaged from said pawl and said cam shifts said ratchet wheel on said hand wheel 7i shaft relative to and held by saidpawl to a position where said clutch teeth are disengaged whereupon the brakes are released while said hand wheel remains stationary.

4. In a hand brake mechanism, the combination with a rotary chain winding drum and a main gear wheel of: a hand wheel shaft mounted for rotation about an axis parallel to the axis of rotation of said chain winding drum and main gear wheel, a hand wheel fast on said hand wheel shaft, a pinion rotatably and non-slidably mounted on said hand wheel shaft engagin said gear wheel and having clutch teeth on the side facing said hand wheel, a ratchet wheel nonrotatably and slidably mounted on said hand wheel shaft and having clutch teeth on one side for engaging said clutch teeth on said pinion and a cam follower collar on the other side, a pawl biased into engagement with said ratchet wheel to prevent reverse rotation thereof and slidable with respect to the teeth thereof when the same is shifted on said hand wheel shaft, a counterweight on said pawl biasing it out of engagement with said ratchet wheel, a rookably mounted trip handle shaft, a trip handle fast on said trip handle shaft, a hold down arm on said trip handle shaft for engaging said pawl and holding it in en agement with the teeth of said ratchet wheel, and a cam fast on said trip handle shaft and operating with said cam follower collar for shifting said ratchet wheel along said hand wheel shaft to engage and disengage said clutch teeth, said hold down arm and cars being so related on said trip handle shaft that in one extreme position of said trip handle said hold down engages said pawl and holds the same in engagement with said ratchet wheel while said clutch teeth are engaged, in an intermediate position of said handle said hold down arm is disengaged fr pawl and the same can swing after the force therecn is relieved by tightening the brakes slightly by said hand wheel under the influence of counterweight out of engagement with said ratchet wheel while said clutch teeth remain in engagement whereby said hand wheel can rotate in a. reverse direction to provide a graduated release of the brakes, and in the other extreme position of said trip handle said hold down arm remains disengaged from said pawl and said cam shifts said ratchet wheel on said hand wheel shaft relative to and held by said pawl to a pcei n where said clutch teeth are disengaged whereupon the brakes are released while said hand wheel remains stationary.

5. In a hand oral-1e mocha sm, the =oombination with a rotary chain winding drum and a main gear wheel of a hand wheel sh ft mounted for rotation about an axis parallel the axis rotation of said oh wir g drum and main gear wheel, said hand wheel shaft having a pinion bearing surface on one end, an intermediate noncircular bearing surface, and a hand wheel attaching portion at the other end; hand wheel fast on said hand wheel attaching portion, a pii ion rotatably mounted on 'nion bearing 5 face and engaging said wheel and having a ratchet wheel having greater than that of s pinion ed on said non-circular hearin 5 snriace and fotatable with said hand wheel shaft having clutch teeth on one side for engaging said clutch teeth on said pinion and a cam follower collar on the other side, a pawl cooperating with said ratchet wheel to prevent reverse rotation thereof the same is shifted on said hand wheel shaft, a trip handle shaft mounted for rotation about an axis parallel to the aXis of rotation of said hand wheel shaft, a trip handle fast on said trip handle shaft, and a cam fast on said tri handle shaft and cooperating with said cam follower collar for shifting said ratchet Wheel along said hand wheel shaft to engage and disengage said clutch teeth, said cam being so positioned on said trip handle shaft that in one position of said trip handle said clutch teeth are engaged, and in another position of said trip handle said cam shifts said ratchet wheel on said hand wheel shaft relative to and held by said pawl to a position where said clutch teeth are disengaged whereupon the brakes are released while said hand wheel remains stationary.

6. In a hand brake mechanism, the combination with a rotary chain winding drum and a main gear wheel of a hand wheel shaft mounted for rotation about an axis parallel to the axis of rotation of said chain winding drum and main gear wheel, said hand wheel shaft having a pinion bearing surface on on end, an intermediate noncircular bearing surface, and a hand wheel atta hing portion at the other end; a hand wheel fast on said hand wheel attaching portion, a pinion rctatably mounted on said pinion bearing surface and engaging said gear wheel and having clutch teeth on the side facing said hand wheel, 1" tchet wheel having a diameter substantially c ter than that of said pinion slidabiy mounted aid IlOll ClI-idlhl bearing surface and rotatabi with said hand wheel shaft and having clutch teeth on one side for engaging said clutch teeth on said pinion and a cam follower collar on the other side, a pawl biased into engagement with said ratchet wheel to prevent reverse rotation thereof and slidaole with respect to the teeth thereof when the same is shifted on said hand wheel shaft, a trip handle shaft mounted for rotation about an axis parallel to the axis of rotation of said hand wheel shaft, a trip handle fast on trip handle a hold down arm on said "'rip handle shaft for engaging said pawl and holding it in engagement with the teeth of said ratchet wheel, and a cam fast on said trip handle shaft and cooperating with said cam follower collar for shifting said ratchet wheel along said hand wheel shaft to engage and disengage said clutch teeth, said hold down arm and cam being so related on said trip handle shaft that in one position of said trip handle said hold down arm engages said pawl and holds the same in engagement with said ratchet wheel while said clutch teeth are engaged, and in another position of said trip handle said hold. down arm is disengaged from said pawl and said cam shifts said ratchet wheel on said hand wheel shaft relative to and held by said pawl to a position where said clutch teeth are disengaged whereupon the brakes are released while said hand wheel remains stationary.

'7. In a hand brake mechanism, the combination with a rotary chain winding drum and a main gear wheel of a hand wheel mounted for rotation about an axis parallel to the axis of rotation of said chain winding drum and main gear wheel, said hand wheel shaft having a pinion bearing surface on one end, an intermediate non-circularbearing surface, and a hand wheel attaching portion at the other end; a hand wheel fast on said hand wheel attaching portion, a pinionrotatably mounted on said pinion bearing surface and engaging said gear wheel-and having clutch teeth on the side facing said hand wheel, a ratchet wheel having a diameter substantially greater than that of said pinion slidably mounted on said non-circular bearing surface and rotatable with said hand wheel shaft and havini, clutch teeth on one side for engaging said clutch teeth on said pinion and a cam follower collar on the other side, a pawl cooperating with said ratchet wheel to prevent reverse rotation thereof and slidable with respect to the teeth thereof when the same is shifted on said hand wheel shaft, a counterweight on said pawl biasing it out of engagement with said ratchet wheel, a trip handle shaft mounted for rotation about an axis parallel to the axis of rotation of said hand wheel shaft, a trip handle fast on said trip handle shaft, a hold down arm on said trip handle shaft for engaging said pawl and holding it in engagement with the teeth of said ratchet wheel, and a cam fast on said trip handle shaft and cooperating with said cam follower collar for shifting said ratchet wheel along said hand wheel shaft to engage and disengage said clutch teeth, said hold down arm and cam being so related on said trip handle shaft that in one extreme position of said trip handle said hold down arm engages said pawl and holds the same in engagement with said ratchet wheel while said clutch teeth are engaged, in an intermediate position of said trip 10 handle said hold down arm is disengaged from said pawl and the same can swing after the force thereon is relieved by tightening the brakes slightly by said hand wheel under the influence of said counterweight out of engagement with said ratchet wheel while said clutch teeth remain in engagement whereby said hand wheel can rotate in a reverse direction to provide a graduated release of the brakes, and in the other extreme position of said trip handle said hold down arm remains disengaged from said pawl and said cam shifts said ratchet wheel on said hand wheel shaft relative to and held by said pawl to a position where said clutch teeth are disengaged whereupon the brakes are released while said hand wheel remains stationary.

FRANK E. BRETZ, JR.

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

UNITED STATES PATENTS Number Name Date 1,877,027 OC'onnor Sept. 13, 1932 1,938,885 Wrigley Dec. 12, 1933 2,071,269 Bartsch Feb. 16, 1937 2,112,235 Camp Mar. 29, 1938 2,229,827 Van Cleave Jan. 28, 1941

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