US1039555A - Dash-pot. - Google Patents

Description

A. u. JJIVERMORE.

DASH POT. APPLICATION FILED JUNE 13, 1911. 1,039,555. Patented :Sept. 24, 1912.

2 SHEETS-SHEET 2.

FIG. 3

WITNESSES [NVEN TOR.

yf'/' 137 am A. G. LIVERMURE.

DASH POT.

APPLICATION FILED JUNE 13, 1011.

Patented Sept. 24, 1912.

2 BKEBTBSHEET 1.

[NV NTOR. .4. 151

WITNESSES 06 ATTORNE s'rnrns PATENT-omen.

ARTHUR e; IIVEBMOBE, or nncnwoon PARK, rmmsx'nvninn, nssmnori To win:

UNION- swrrcn a stoma. company, or swrssvam', Psmsiznvmm, A oonro- BATION OF PENNSYLVANIA.

nAsn-re'r.

Specification of Letters Patent.

Patented sepa ze, 191s,

Application filed June 13, 1911. Serial 1T0. 682,831.

To all whom it nuiy ing at Edgewood Park, in the .county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Dash-Pots, of which the following is a specification.

My invention relates to bufiing devices for railway signals, and particularly to air bufiers for railwaysignals of the semaphore type having a plurality of positions of indication.

I will describe one form of air bufier embodying my invention, and then point out the novel features thereof in claims.

In the accompanyingdrawings, Figures 1, 2 and, 3 are views showing a semaphore signal in three different positions of indication, and showing a buffing device embodying my invention with its parts in the three corresponding posit-ions. Fig. 4. is a vertical sectional View showing in detail the form of buifing device illustrated in Figs. 1, 2 and 3.

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

Referring to Fig'sl'1,,2 and 3 of the accompanyingdrawings, A designates a railway semaphore signal, and B a mechanism for moving it. The semaphore signal comprises as usual a-blade 5-and a spectacle casting 6. Thesemaphore is suitably fixed on a shaft 7 ,and when free to move always 35 assumes a'horizontal position of'the blade under theinfluence of gravity on the. blade and on the spectacle casting. In the drawings I have shown the semaphore as being adapted for movement from its horizontal position upwardly to two other'positions of indication, but it may equally'wellbe adapted for movement from its horizontal position downwardly to other positions of mdication. These arrangements arezwell under stood by those skilled in the art and involve merely mechanical changes which need not be explainedherein. The operating mechanism B as here shown comprisesan arm 8 pivoted at one end and provided at its other end. with a fork 9 pivoted to the arm and adapted to beheldarigid with: the arm by means of an electromagnet 30, and suitable appara uscarried f hy the arm. .10 and 13 designate-chains driven by, 'a motor 11, which-- chains are provided with projections ar: ranged to engage the fork 9 to raise the arm.. Stationary supports 14 and 15 are also provided to engage with the fork to hold the arm in the positions to which it has been moved. The arm 8 is connected with the semaphore by means of a rod 12 and a suitable crank secured to the semaphore shaft 7 An operating mechanism of the general type such as I have herein shown is shown and described in United States Letters Patent No. 611943 issued on October 4, 1898', to, J.- G. Schreuder. It is understood, however,

that I do not wish to limit myself to any specific type'of operating mechanism.

As here shown the semaphore A. is moved by the mechanism B from the horizontal position, (usually the danger position) to an inclined position (usually the can- During the return movements of the semaphore, it is desirable that the momentum of the parts should be checked before they reach the positions corresponding tothe tin clined and horizontalpositions of the se'r'na-- phore. This I accomplish by means of a bufiing device embodying my invention, one form of which I will now describe.

. A buflin comprises hut one cylinder-and but one; piston having relative movements, and 'this buffing device serves to cushion the moving parts as they approach both the inclinedv and horizontal positions ofthe semaphore. As the parts approach the inclined position,-

the piston is substantially -midway' of its stroke through the cylinder, hence the compression of the air inst-he cylinder bythe piston might not at this point be sufficient to eflectivelycushion the movement of the parts. To secure the desired cushioning effect atthe inclined position, I so arrange. the butler as to permit the piston to create a partial vacuum behind itself duringv that portion of'itsstroke corresponding to the movement of the semaphore: from vertical:

t9 inclined positions. By means-of this partral vacuum or by. means .of-the partial vacuum combined with the compression of the air on the other side-"of the pistom. I

effectively cushion themoving parts as they device embodying my invention.

tion position) and to a substantially vertical position (usually the clear ?'position').

of the cylinder, and the partia approach the inclined positio phore. During the moveme V I phore from the inclined to th -horizont-a-l position, the piston is approach" hind the piston is not usually necessary during this portion of the stroke, for the reason that the parts can then be effective] cush ioned by the compression of air in rent of mechanism at 31 and the piston is opera-' tivcly connected with the arm 8 by means of a piston rod 18 and a yoke 32. It is understood, however, that this arrangement may equally well be reversed, the piston being fixed and the cylinder being operatively I connected with the arm 8. The cylinder is closed at both ends, being provided at its upper end with a head 20 which carries a stufiing box 21 through which passes the piston rod 18.

22 designates a check valve at the upper end of the cylinder, here shown as compris-v ing a ball 23 resting inia suitable conical seat. This valve permits the air to be freely driven out of the upper part ofthe cylinder during the. upward movement of the piston, but prevents the flow of air into the upper part of the cylinder during the downward movement of the piston. Adjacent the lower end of the cylinder is a similar check valve 2 1 here shown as comprising a ball 25 which permits air to flow freely into the lower ortion. of the cylinder during the upwar movement of the piston, but which prevents the outflow of the air under comvpression in the lower'portion of the cylinder during the downward movement of the piston.

28 designates an adjustable relief valve by means of which the outflow of air from the lower portion of the cylinder during the downward or compression stroke may be regulated to avoid complete stoppage of the moving parts and yet to provide the desired cushioning effect. If desirable, a similar adjustable valve 29 may be provided at'the upperend of theited influx of air suction stroke of the piston, although the leaka e of'air through the stufling will usual y render this relief valve unnecessary. It will be clear'that with a as thus 'far described, the pressure 0 the air rg'linder to permit a lim uring the downward or.

device inthe cylinder-above the piston will be reduced below. atmospheric (pressure as soon as the piston begins its ownward movement, and that thls pressure will constantly become lower-as the piston moves farther away from theupper head. The first part of the movement of the semaphore from its vertical position will therefore be comparatively rapid, but the momentum of the parts willbe checked by the partial vacuum above the piston as the semaphore approaches its inclined position, thereby providing the desired cushioning effect at this point. The cushioning eifect is assisted, as hereinbefore mentioned, by the compression of air ahead of the piston.

If no meanswere provided for relieving the partial vacuum behind the piston after the semaphore has reached the inclined position, it is evident that the entire move ment from the inclined to the horizontal position would be extremely slow. It is desirable however, that the early part of this movement should be rapid, and that the momentum of the moving parts should be checked only as thesemaphore approaches its horizontalvposition. In order to relieve the partial vacuum I preferably provide a rod secured to the piston and passing out through a stufling box in one end of the cylinder, which rod is provided with air passages so arranged as to connect the end of the cylinder in which the partial vacuum exists with the atmosphere during the move ment of the semaphore between its inclined and horizontal positions. As shown in Fig.

4 I em loy the piston rod 18 for this pur pose, a thou h I do not wish to be limited 7 with a longitudinal passage 19 which communicates with the atmosphereat 27 where the piston rod unites with the yoke 32.

26 designates a transverse opening through thewall of the rod 18 communicating with .thepassage 19. This transverse opening is so located as to be within the cylinder while the semaphore is between its horizontal and inclined positions, but to be opposite the stufling box 21 or inthe outside alr while the semaphore is between its inclined and vertical positions. 7

It will be evident from the foregoing explanation that after the semaphore has reached the inclined position on its movement towardhorizontal the end of the cylinder'in which the partial vacuum exists is" opened to atmosphere and that from theinclined to the horizontal position the cush-T ioriing efiect is obtained solely by the-com-' presslon of air ahead of the piston. 4 Although I have herein shown and described only one form of air bufier embodying my invention, it is understood that various modifications may be made therein Within the scope of the appended claims without departing from the spirit and scope of my invention.

. Having thus I claim is': V

1. A butiing device comprising a cylinder and a piston having relative movement, the said movement in one direction being retarded throughout an entire strokeby the compression of air on one side'of the piston and through a portion of the said stroke by a partial vacuum created on the other side of the piston by the said movement. 7

2. A'bufling device comprising a cylinder and a piston having relative movement, the said movement in one direction being retarded throughout the stroke by-the compression of air onone side ofthe piston and through a portion of the strokeby the par tial vacuum created on the other side of the piston by the said movement, and means for relieving the partial vacuum. during theremainder of the said stroke.

3. A bufling device comprising a cylinder and a piston having relative movements, the cylinder being closed at both ends to permit the relative movement to create apartial vacuum on one side of the piston during a portion of on the other side of the piston during the entire stroke, and means for opening the cylinder on the vacuum side of the piston to atmosphere aztter the said portion of the said stroke has been completed.

described my invention, what 4. A buiiing devicecomprising cylinder and a piston having relative movements, the

cylinder being closed at both ends to permit the relative movement in one direction to create a partial vacuum-on one side of the piston during a portion of a stroke and a compression of air'o-nthe other side of the piston during the entire stroke, means for opening the cylinder on the vacuum side of the piston to atmosphere after the said portion of the said stroke has been completed,

and check valves in each end of the cylinder to permit a free relative movement in the opposite direction.

5. A bufiing device comprising a cylinder and a piston having relative movements, the cylinder being closed at both ends to'permit the relative movement in one direction to create a partial vacuum on one side of the piston during'a portion of a stroke and a compression of air on the other piston during the entire stroke, means for opening the cylinder on the vacuum side of the piston-to atmosphere after thesaid portion of the said stroke has been completed,

and a release valve in the cylinder onthe compression side of the piston to permit a slow outflow of air during the movement in the said direction.

a stroke and a compressionof air side of the 6.-A buflin device comprising a cylinder and a pistonhaving relative movements, the cylinder being, closed at both ends to permit the relative movement in one direction to create a partial vacuum on one side of the piston during a portion ofa stroke and a compression of air on the other side of the piston during the entire stroke, means for opening the cylinder on the vacuum side of the piston-to atmosphere after the said portion of the said stroke has been completed, and-a release valve in the cylinder on the vacuum side of, the piston to'permit a slow inflow of air during the movement in the said direction. 1

Y 7. A buflin device-comprising a cylinder and a piston aving relative movements, the

cylinder being-closed at both ends, a rod connected with the piston and passing through one end of the cylinder, a longitudinal .passage in said rod open to atmosphere at all times, and an opening through the wall-of the rod communicating with the passage and :located to be outside of the cylinder during a portion of the relative movement andin side of the cylinder. during the remainder of the movement.-

8. Abulfing device comprising a cylinder and a piston having relative movements, the cylinder being closed atone end, a'rod connected with the piston and passing through the-closed end of the cylinder, a longitudinal passagethrough said rod open to atmo-s phere at all times, and an opening through the wall of-the rod communicating with the said passage and located to be ithin'the closed end of the cylinder during a portion of the relative movement and outside of t e saidclosed end during-the i'emainder of t e relative movement.

9. A bufiing device comprising a cylinder and a piston having relative movement, the

cylinder belng closed at" both ends, a rod connected with the piston and passing through one end.ofthe cylinder, and a passage throughithe rod one end of which is open to the atmosphere at all times and the other end of which is within the cylinder during a portion of the relative movement and without thecylinder during the remainder of the relative movement.

10. A bufling device comprising a cylinder and a piston having relative movement, the cylinder being closed at both ends to cushion the relative movement during a portion of a stroke by a partial vacuum and during the entire stroke by compression.

11. A bufiing device comprising a cylinder and a piston havingrelative movement, the said relative movement in one direction being retarded throughout the entire stroke .by compression on one side of the piston, and:

through substantially the first half of said stroke by other sideof the piston by said-strove he partial vacuum created'on'the through substantially the'first half of said.

7 said stroke.

comprised in said rod for relieving the said v der and .a piston having relative movement,

the cylinder being closed at both ends, a rod connected :with the piston and, passing through one of the said closed ends, the

ment, and means for relieving said partial vacuum during substantially the last half of said stroke.

12. A butting device comprising a cylinder and a piston having relative movement, the said relative movement in one direction being retarded throughout the entire stroke by compression on one side of the piston, and

stroke by the partial vacuum created on the other side of the piston by the said movement, and means for opening the vacuum side of the cylinder to atmosphere during substantially the last half of said stroke.

13. A. buffing deviceecomprising a cylinder and a piston having relative movement, the cylinder being closed at one end, a rod connected WllZ-l1 the piston and passing through the closed end, the relative movement in one direction being retarded through a portion'of the stroke by the partial vacuum created between the piston and the closed end by such relative movement, and means partial vacuum during theremainder of the 14. A butting device comprising a cylin the cylinder being closed at one end, a rod connected with the piston and passing through the. closed end, the relative movement in one direction being retarded through a portion of the stroke by the partial vacuum created between the piston and the closed end by such relative movement, and means comprised in said rod for openingthe said closed end of the cylinder to atmosphere during the remainder of the stroke. I

- 15; A butfing device comprisinga cylinder and a' piston having relative movement,

relative movement in one direction being retarded throughout the entire stroke by the compression on one side of the piston'and through the first portion of said stroke by I the partial vacuum created on the other side of the piston by the said relative movement,

through a portion of the said stroke by the partial vacuum created onthe other side of the piston by the said movement, and means for opening the cylinder on the vacuum side of the piston to atmosphere during the re mainder of the said stroke.

17. In combination, a movable device adapted to move from. one position to a second position and to continue the movement inlthe'same direction from saidsecond position to a third position, a buffing device for cushioning the movement as the said 'movable device approaches the said second osition and the said third position, said ufiing device comprising a cylinder and a 'piston having relative movement one of which is connected with the movable device,

the said relative movement being cushioned throughout the entire stroke of the movable device by the compression on one side of the piston and through the portion of the stroke of the movable device from the first to the second position by the partial vacuum cre-' ated on the 1 other side of the piston bythe said relative movement, and means for relieving the partial vacuum during the move- -ment from the second to the third position.

In testimony "whereof I afiix my signature in presence of two witnesses.-

Witnesses:

, -A. L. VENGILL, P. F. WILLARD.

ARTHUR o. LIVERMORE,

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