US2158055A

US2158055A - Hand brake

Info

Publication number: US2158055A
Application number: US91059A
Authority: US
Inventors: Richard W Burnett
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-07-17
Filing date: 1936-07-17
Publication date: 1939-05-16
Anticipated expiration: 1956-05-16

Description

HAND BRAKE Filed July 17, 1936 May 16, 1939.

I5 Sheets-Sheet 1 Q Q 5 I INVENTOR Rigard WBurnez t ATTO RNEYS y 6, 1939. R w BURNETT 2,158,055

HAND BRAKE Filed July 17, 1936 3 Sheets-Sheet 2 INVENTOR iiicgard WBurnezt W M wmp ATTORNEYS y 1939- R. w. BURNETT 2,158,055

HAND BRAKE Filed July 17, 1936 3 Sheets-Sheet 3 y INVENTOR 4g Ricgard W Burnett 40 M M 9 ATTORNEYS Patented May 16, 1939 UNITED STATES PATENT OFFICE 1mm) 1mm Richard w. Burnett, cliimo, 111. Application July 17, 1955, Serial No. 91,059 1i Claims. (c1. lac-81.1)-

This invention relates. to railway car hand brakes.

One of the objects of this invention is to provide asimple, inexpensive and practical hand brake mechanism which is well adapted to meet the varying conditions of practical use. Another object is to provide a hand brake mechanism of the above character which is efllcient, durable and reliable under conditions of rigorous use. Another object is to provide a hand brake mechanism of the above character which is compact and relatively light in weight and which may be easily operated with a maximum of safety. Other objects will be in part obvious and in part pointed out hereinafter.

This invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings. in which is shown one of the various possible embodiments of my invention, 4

Figure'l is a front plan view of the mechanism positioned within the housing, of which portions are broken away;

Figure 2 is a vertical-sectional view taken along line 22 of Figure 1;

Figure 3 is a horizontal sectional view of the housing taken along line 33 of Figure 2;

Figure 4 is an enlarged plan view of some of the parts shown in Figure 1;

Figure 5 is an enlarged plan view similar to Figure 4 but showing the parts in different positions;

Figure 6 is a sectional view taken 66 of Figure 5;

Figure 7 is an enlarged front plan view, similar to Figure 5, of a modification of my construction; and,

Figure 8 is a sectional view taken along line 88 of Figure 7. 7

Similar reference characters refer to similar parts throughout the several views of the drawmgs.

Referring now to the drawings in detail and to Figure 2 in particular, the handbrake mechanism is mounted in a. housing generally indicated at l0 which preferably comprises a back plate generally indicated at H and a front plate generally indicated at l2. Front plate l2 preferably has a rearwardly extending flange l3 (see also Figure 1) formed thereon which abuts along line against back plate II and extends around the outer edges thereof, having an opening Illa along the lower edge of the housing, as may be seen in Figure 1. Front plate I2 is attached to back plate H in any suitable manner andthe housing is suitably secured to the'side wall of a railway 6 car.

In the lower portion of the housing, and preferably mounted upon machined lugs l4 and I5 (Figure 2) which are preferably integral with and project from plates II and I2 respectively I 10 provide a large gear l6 which is preferably formed integrally with a winding drum l1. Positioned in the upper part of the housing above gear 16 is a shaft I 6 preferably supported in the housing by a journal I9 and a bearing 20 formed in plates 15 II and I2 respectively. Shaft l8 preferably has integrally formed therewith a pinion gear. 2| which meshes with drum gear l6; shaft l8 preferably having one end 18a extending through front plate l2 of the housing to provide a mount- '20 ingfor a hand wheel 22. Hand wheel 22 'is so secured to shaft l8 that rotation thereof is transmitted through pinion gear 2| and gear l6 to the winding drum IT. The winding drum in turn is operatively connected to the brake rigging (not 25 shown) of the railroad car by a chain, the end link 23 of which is shown as connected to wind- 'ber 26 comprises a pawl 21 (Figure 2) adapted to engage ratchet wheel 25, and a tail portion 26 also'adapted to engage ratchet wheel 25 to 40 retard reverse movement thereof, as will be described more fully hereinafter. Member 26 has a web 29 (Figures 1 and 2) preferably formed integrally therewith, which is positioned above pawl 21 and extends rearwardly or to the left of mem- 46 ber 26 as viewed in Figure 2. V v To the right of part 26, as viewed in Figure 1,

is a shaft 36 which is mounted in housing ll parallel to the pivotal axis of member 26; Secured to shaft 36 and positioned externally of the housing I6 is a tripping lever 25 (Figures 2 and 3). Pivotally mounted upon shaft 36 is a tripping cam generally indicated at 3| which has a pair of

jaws

32 and 33 extending to the left of its axis as viewed in Figure 1, these jaws be- 66 wheel 25. If the tripping cam is'moved countera clockwise, Jaw 32 engages the upper surface .of web 23 to move the pawl into engagement with the web.

.A recess N is provided in triPP 8 cam 3|, ad- Jacent shaft 33, and integral with shaft 33 I provide a lug 33 which moves freely in recess 33 until it abuts against one end 34a or the other end 3: thereof. Thus when tripping lever 35 is moved clockwise, as viewed in Figure i, there is a certain amount of free or lost movement before lug 33 abuts recess end 33a to cause lower jaw 33 to enga e web 23. similarly if the tripping lever were moved counter clockwise to efiect an abutment between mg 33 and recess end 34b causing the pawl and ratchet to disengage, there would be a certain amount of free or lost movement of the lever before the upper Jaw of the tripping cam forced the pawl into engagement with the ratchet,allofwhichisforapurposetobemore fully disclosed hereinafter.

- Referring to l'igure6, the sides a and :55 of ratchel wheel 25 are preferably beveled and the tail portion 23 of pawl member 23 has two downwardly extending

lugs

31 and 33, the inner surfaces of which are preferably beveled to substantially the same angle as the beveled sides 25a and 25b of ratchet wheel 25. Preferably

lugs

31 and 33 are so positioned upon part 23 that they engage a substantial portion of the beveled edges of the ratchet wheel while at the same time the under surface 33 (Figure 6) of member 23 is preferably spaced from the ratchet teeth. Accordingly, referring to Figure 1, when pawl 21 is moved out of engagement with ratchet 25 by upward movement of law 33, the tail portion. 23 of part 23 moves downwardly upon ratchet wheel 25. If this movement is continued,

lugs

31 and, 33 are forced into frictional engagement with the sides of the ratchet teeth thus retarding reverse movement thereof.

Member 23 is preferably so proportioned that its natural tendency is to assume the balanced position shown in Figure 5 i. e., to move in aclockwise direction when neither of

laws

32 or 33 engages its web portion 23. In this position there is no engagement between the ratchet teeth and pawl 21 and either no engagement or very loose engagement between the ratchet teeth and beveled lugs 31 and- 33. In this connection, it should be noted that the lost motion referred to hereinabove and the various parts whereby it is achieved coact with the pawl in effecting efilcient and advantageous operation thereof. For example, when a brakeman is drifting the car over a hump, the car brakes are generally set a certain amount. Under certain circumstances, how ever, the brakeman might desire thecar to roll faster, in which event at least a partial release of 'the brake would be necessary. Such partial release is readily effected by moving lever 35 in a clockwise direction as viewed in Figure 1, to re- Y lease pawl 21 from'its ratcheting engagement ratcheting engagement subsequent to release therefrom, and the car brakes thus may be readengagement from this position is greatly facilitated by the-momentum built up during the lost or ineffective movement of weighted lever 35.-

That is, with reference to Figure i, when weighted lever 35 is flipped over in clockwise direction, lug

'36 .on lever shaft 3|) is free to travel throughoutthe entire extent of recess 34 before engaging end 34a of the recess. During this movement there is, of course, no engagement between law 33 and web 23. However, when lug 33 abuts recess end- 3la, the potential energy built up by the inertia of the weighted lever during its free travel is immediately effective upon the engagement be'tween jaw 33 and web 23 to snap pawl 2I-out of its ratcheting engagement with ratchet wheel 23.

The combined features of the pawl and the above-noted lost motion mechanism effect the further advantage of definite and immediately ascertainable. control in that the brakeman can immediately determine not only whether weighted lever 35 is in aposition to set or release the pawl, but also the exact point at which such release or engagement may be effected.

In operation, if the user desires to set the brakes, he throws lever 35 'to the position shown in Figure 1. when in this position, jaw 32 presses downwardly upon web 29 forcing and holding the pawl in engagement with ratchet wheel 25. Then hand wheel -22 is whirled in a clockwise direction as viewed in Figure 1, causing gears 2i and i8 .to-rotate the winding drum l1, and operate the brake rigging (not shown) through chain 23. The pawl 21 (Figure 1) at this time is held in engagement with ratchet wheel 25 by the weight of lever acting through cam 3i to prevent reverse movement of the parts. when the user decides to instantaneously release the brakes, the lever is moved clockwise (Fl re 1). Referring now to Figure 4, lever 35 ves freely to the right until lug 33 engages end 340 of recess 34. At this time the lever is positioned as shown in Figure 4. Further movement of the web 23, forcing pawl 21 out of engagement with ratchet wheel 25. It should be noted that by continuing the movement of the lever in this same direction, jaw 33 continues to bear upwardly upon web 23 causing beveled lugs 31 and 33 on the tail portion of part 23 to frictionally engage the ratchet wheel.

Thus the user by swinging the lever to the right as viewed in Figure 2 releases the mechanism and immediately controls the amount of release thereof by means of the frictional engagement of the lugs with the ratchet wheel. This extremely short interval between the releasing and braking action prevents the parts from attaining any great speed of rotation before the braking action of member 26 takes efiect,v and also prevents the hand wheel from spinning. In

leverin this direction causes jaw 33 to engage other words, the user at all times has complete control of the releasing of the hand brake.

Because part 26 is unbalanced when pawl 21 is engaged with ratchet 25 as described hereinabove, the pawl can not drop .into engagement with the ratchet wheel after it has been released therefrom, without manual actuation. Thus,

excessive shock to the engaging parts is avoided. In order to re-engage the pawl and the ratchet wheel after release thereof, lever II is moved to the left, as viewed in Figure l, and when lug 36 engages the upper end 34b of recess 34 in the cam, jaw 32 engages web" to force the pawl into engagement with the ratchet wheel. When in this position, the hand brake mechanism is conditionedfor operation of hand wheel 22 to set the brakes.

Referring now to Figures 7 and 8 the tail portion 28 of member 26 may have a brake shoe generally indicated at 40 pivotally mounted therein which serves as the brake. Shoe 4. preferably has an upwardly extending projection 4| (Figure 8) formed thereon which extends into a recess 42 formed in the tail portion 20 of member 26. A pin 43 extends through the tail portion and pivotally mounts upwardly extending projection 4i therein. Refen'ing now to Figure 7 the upper portion of projection 4i has slanting sides 44 and 45 which are in substantial registry with the sides of recess 42 which also slant but preferably at a greater angle. The brake shoe 40 freely pivots about pivot pin 43 but its pivotal movement is limited by the sides of recess 42.

The lower portion 46 of part 40 has lugs 41 and '48 formed thereon which are substantially similar to lugs 31 and 3B (Figure 6) and which engage beveled sides of the ratchet wheel 25 in a manner substantially similar to that described hereinabove. It may now be seen that braking shoe 40 is readily replaceable and, in use, adlusts itself to the beveled sides of ratchet wheel 46.

Thus I have provided a construction including eflicient means for retarding the brake-releasing movement of the mechanism. Further, the mechanism has been so constructed that the possibility of shock due to uncontrolled engagement of some of the parts has been eliminated. This feature further permits a lighter construction of the various parts which reduces the weight and cost of the mechanism as a whole. Also, the user of this mechanism, when releasing the brakes, always has complete control over release and engagement of the mechanism.

Thus I have provided a thoroughly durable and eflicient construction in which the several objects hereinabove referred to, as well as many others, are successfully accomplished.

As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matters hereinabove set forth, or shown in the accompanying drawings, is to be interpreted as illustrative and not in a limiting sense.

I claim: I

1. In hand brake mechanism, in combination, means for preventing reverse movement of said mechanism comprising a ratchet and a detent, means for moving said detent out of engagement with said ratchet, and means formed upon said detent to engage the sides of said ratchet, said last-mentioned means being adapted to be moved by said second-mentioned means into position to retard reverse movement of said mechanism.

2. In hand brake mechanism, in combination, a housing, a member pivotally mounted in said housing, a ratchet wheel, a pawl formed upon said member adapted to engage said ratchet wheel to prevent reverse movement of said mechanism, a pair of beveled lugs formed upon said member, said beveled lugs being adapted to engage the sides of said ratchet wheel, and means adapted to move said beveled lugs into and out of engagement with said ratchet wheel.

3. In hand brake mechanism, in combination, a member, a detent. formed upon said member, means adapted to be engaged by said detent to prevent reverse movement of said mechanism, a lever, a cam positioned between said lever and said membeFand operatively connected. to said lever and said member, whereby movement of said lever moves said detent into and out of engagement with said means, and means formed on said member adapted to engage the sides of said first-mentioned means upon movement of said lever to retard reverse movement of said mechanism.

4. In hand brake mechanism, in combination, a detent, a member engaged by said detent, means for moving said detent into and out of engagement with said member, and means pivotally connected to said detent adapted to engage the sides of said member to retard reverse movement of said mechanism.

5. In hand brake mechanism, in combination, means to set a brake, means to release said brake, a braking device comprising a pivotally mounted member having a part pivotally mounted thereon,

a rotating member, said part being adapted to engage said rotating member, and means to force said part into engagement with said rotating member when said brakes are released.

6. In hand brake mechanism, in combination. means for preventing reverse movement of said mechanism comprising a ratchet and a pawl, means for moving said pawl out of engagement with said ratchet, the center of mass of said pawl being so positioned with respect to its axis of movement that upon release the pawl moves of its own accord out of engagement with said ratchet, and means formed on said pawl to engage the'sides of said ratchet when the pawl is moved in ratchet releasing direction to retard reverse movement of the ratchet.

7. In hand brake mechanism, in combination, means for preventing reverse movement of said mechanism comprising a ratchet and a pawl, means for moving said pawl out of engagement with said ratchet, said pawl being movable through an arc of less than 90" from its ratchet holding to ratchet releasing positions, and means formed on said pawl to engage the sides of said ratchet when the pawl is moved in ratchet releasing direction to retard reverse movement of the ratchet.

8. In hand brake mechanism, in combination, means for preventing reverse movement of said mechanism comprising a ratchet and a pawl, means for moving said pawl out of engagement with said ratchet, said pawl being movable through an arc of less than 90 from its ratchet holding to ratchet releasing positions, means formed on said pawl to engage the sides of said ratchet when the pawl is moved in ratchet releasing direction to retard reverse movement of the ratchet, and operating means for said pawl including a hand lever movable through an arc greater than 90 to force said pawl into ratcheting position in one direction of movement and to effect said reverse retarding movement of the ratchet in its other direction of movement.

9. In hand brake mechanism, in combination, means for preventing reverse movement of said mechanism comprising a ratchet and a pawl, means for moving said pawl out of engagement with said ratchet, means formed on said pawl to engage the sides of said ratchet when the pawl is moved in ratchet releasing direction to retard reverse movement of the ratchet. and operatinz means for said pawl including a hand lever swingable throughan arc greater than 90 10. In hand brake mechanism, in combination, a detent, a member engaged by said detent, means for moving said detent into and out oi! engagement with said member to selectively alter the operative condition of said mechanism, and

means formed on said detent having at least one portion adapted to ensure a side oisaid member to retard reverse movement of said mechanism. 11. In hand brake mechanism, in combination, a detent, a member engaged by said detent,

means for moving'said detent into and out of engagement with said member to selectively alter the operative condition of said mechanism, and spaced portions formed on said detent adapted to be moved into engagement with the sides of said member by said means to retard reverse movement of said mechanism.

momma w. mm.