US1421721A - Door-operating appliance - Google Patents

Description

J. G. ROBENSON DOOR OPERATING APPLIANCE. APPLICATION FILED JAN,25, 1915.

1,42; 1,?2 l Patented July 4, 19.220

3 SHEETSSHEET I.

t e M) o IIHH TUI lu o 6 I afi l i I] OW J. G. ROBINSON. DOOR OPERATING APPLIANCE. APPLICATION HLED JAN.25. 1915.

Patented July 4, 1922.,

3 SHEETS-SHEET 3.

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JAY Gr. ROBINSON, OF CHICAGO, ILLINOIS.

DOOR-OPERATING APPLIANCE.

Specification of Letters Patent.

Patented July t, 1922.

Application filed. January 25, 1915. Serial No. 4,358.

T 0 all whom it may concern:

Be it known that I, JAY G. ROBINSON, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Door-Operating Appliances, of which the following is a specification.

This invention relates to door operating appliances, particularly to fluid actuated mechanism for opening and closing doors, and is an improvement on an earlier device which has been in use to a considerable extent, and which has a somewhat similar mode of operation.

My invention is especially adapted for use in operating the fire doors of fire boxes, such as a locomotive fire box, in which case, for example, the frequent necessity of opening and closing the doors for firing requires that a quick-acting door operating means he employed in order to avoid the cooling of the interior of the fire box and other evil consequences following the continuance of the doors in open position.

One object of my invention is to provide means for quickly opening the fire doors when the operator is ready to introduce fuel into the fire box, while at the same time providing a mechanism which may be caused to automatically and quickly close the doors as soon as the fuel has passed through the door opening.

A further object of my invention is to provide a door operating appliance in which the actuating mechanism will operate to quickly open the door during its initial and the major part of its opening movement, but in which the doors will have a relatively slow final opening movement owing to an im proved cushioning device which I. provide for that purpose. The novel and efficient means which I provide for cushioning the door or doors and the operating mechanism, during the latter portions of their opening movements, constitutes a very important feature of my invention. 1 also provide means for giving the doors a relatively rapid movement during the early and major portions of their closing movements, while providing cushioning means for retarding the doors and causing them to move relatively lowly during the latter stages of their closing movements.

These and other objects will be set forth more particularly in the following specification taken in connection with the accompanying drawings, in which I have illustrated a specific embodiment of my inven tion.

In the drawings;

Fig. 1 is. a rear elevation of a locomotive fire box showing my improved door operating mechanism arranged in operative relation to the fire doors thereof;

Fig. 2 is a vertical section through a portion of my door operating appliance show ing certain parts in elevation;

Fig. 3 shows a vertical longitudinal section through the foot valve of my apparatus;

Fig. a shows a vertical transverse section through the structure shown in Fig. 3;

Fig. 5 shows a perspective view of the follower which forms an element of the metallic packing for the piston rod at one extremity of the cylinder;

Fig. 6 shows a perspective view of a packing ring adapted to coact with the member shown in Fig. 5;

Fig. 7 shows a view partially in elevation, and partially in section, of a packing nut for use in connection with the elements shown in Figs. 5 and 6; and

Fig. 8 shows an elevation of a spring and a sectional view of a washer which are adapted to be used in connection with the elements shown in Figs. 6, 7 and 8.

Like numerals refer to like parts and elements throughout the drawings, in which the locomotive, or the like, designated generally by the numeral 10, is provided with a pair of transversely sliding fire doors 11 and 12, which are grooved along their upper and lower edges to engage the downwardly and upwardly projecting flanges, respectively, of the horizontal guide bars 13 and 14, which are secured to the door frame carried by the boiler around the firing opening.

The mechanism for opening and closing the doors comprises the lever 15, which is pivotally mounted on the door frame at the point 16, and provided with a longitudinal slot which is pivotally engaged by the pin 17 on the door 11. The lever 15 is pivotally connected by means of the cross link 18 with the lower depending arm 19 of a bell crank lever 19. The upwardly projecting arm 19 of the lever 19 is provided with a longitudinal slot which. engages the pin 20 closed position.

carried by the door 12. The crank arm 19 of the lever 19 extends outwardly substantially at right angles to the parts 19 and 19, and is pivotally connected to the connecting rod 21. It will be apparent that the down ward movement of the connecting rod will operate the levers 15 and 19 in such a manner as to cause the doors 11 and 12 to slide away from each other on the guide bars 13 and 14*, while the upward movement of the connecting rod will move the doors into In order that the doors may, if desired, be operated independently of the fluid actuated mechanism to be here inafter described, I provide the lever 15 with the upwardly projecting handle 15 which may be engaged by the hand of the operator to move the doors into open or closed position.

The fluid actuated means for actuating the door operating levers comprises a differential cylinder 22 having the lower chamber 23 of relatively small diameter and the upper chamber 24-. of relatively large diameter. The differential cylinder 22 is closed at its upper end by a cap 25 which may be secured to the walls thereof in any well known mannor to form an airtight connection, and the lower end of said cylinder is closed by the cap 26, which is likewise secured to the walls thereof in a manner to form a tight connection therewith. A piston rod 27, having an enlarged portion 27 is mounted to reciprocate in the cylinder 22 and is pivotally connected to the connecting rod 21 Adjacent the shoulder formed at the junction of the enlarged portion 27 and the reduced portion 27 of the piston rod 27, said piston rod carries a piston 28 which reciprocates in the smaller chamber 23, and the upper extremity of said piston rod carries a piston 29 which is secured in position by the nut 30 engaging the end of the piston rod,- and which is adapted to reciprocate in the larger chamber 24 of the cylinder 22. The smaller piston is provided with annular recesses which carry the piston rings 28, and the 7 upper end thereof carries a packing ring-28 of leather or other suitable material, which is retained in position by the retainer plate 28. The upper piston 29 is also recessed to carry the piston rings 29, and the lower end thereof is prvoided with similar packing ring 29 which is held in position by a similar retainer plate 29. It will beapparent that when the piston rod. 27 is in its uppermost position, the piston 28 is at the extreme upper end of the chamber 23, while the pis ton 29 is at the extreme upper end of the large chamber 24.

In order to reciprocate the piston rod 27 with the parts carried thereby, and thereby actuate the door operating levers, I make use of compressed fluid which may be steam,

: compressed air, or the like, and I provide a pipe 31 leading from the source of such compressed fluid supply, such, for example, as a tank of the air brake system. The pipe31 leads through a globe valve 32 and is connected by a pipe 33 with the interior of the cylinder 22 between the inner adjacent faces of the pistons 28 and 29. It willbe apparent that when the globe valve 32 is opened there is a constant communication between the source of compressed fluid supply and the space between the pistons 28 and 29, so that the action of said compressed fluid upon the inner opposing faces of said pistons of different area operates to normally maintain the piston rod 27 in its uppermost position, as illustrated in Fig. 2.

In order to actuate the pistons to make a forward stroke, I extend the pipe 31, leading from the source of compressed fluid supply to the foot valve 34, from which a second pipe 35 leads to the T connection 36. The upper banch 36 of the T connection leads through the inwardly opening check valve 37 through the duct 38 in the cap 25 to the space adjacent the upper or outer face of the piston 29 within the cylinder 22. The lower branch 36* of the T connection leads through the outwardly opening check valve 39 through the port 40 to the chamber 24. As shown in Fig. 2, the port l0 leads from the chamber 2st at a considerable distance below the upper end of said chamber. The amountof opening of the valves 37 and 39 can be regulated by the threaded stems 37 and 39".

From the foregoing description it will be apparent that when the foot valve 34 is operated to permit the passage of compressed fluid from the pipe 31 to the pipe 35, the pressure of said fluid will open the check valve 37 and permit pressure to be exerted on the upper or outer face of the piston 29. This piston will then have equal forces exerted on opposite faces thereof, while the resultant eflective pressure of the compressed fluid on the upper face of the piston 28 will cause the piston rod 27 to make a downward or forward stroke. As soon as the foot valve 34 is released to close the communication between the pipes 31 and 35, the effective pressure on the pistons will be the difference between the pressures exerted on the inner adjacent faces of the two pis being closed by the cap 45, which threadedly engages said casing. The casing comprises an outwardly projecting bracket 46, in the end of which a foot lever 47 is pivotally mounted. The shorter arm ll of the foot lever 47 engages the lower projecting end of the valve stem 43, and it will be evident that when said foot lever is depressed by the operator the end 47 thereof will project the valve 42 upwardly from its seat into the valve chamber 44. VJhen this occurs a communication will be formed from the pipe 31 through the radially extending ducts 18 in the upper end of the valve stem to the longitudinally extending passage 49 in said stem, which communicates adjacent its lower end bymeans of the radially extending ducts 50 with the annular recess or chamber 51. The pipe 35 leads from the valve casing 41 at such a point that it is in communication with the annular chamber 51 when the valve stem 43 is in either upper or lower position. A vent 52 extends through the valve casing and communicates with the annular chamber 51 when the valve stem is in its lower position only.

It will be evident that when the operator depresses the foot lever a8 a communication will be formed between the pipes 31 and 35, thus permitting the actuation of the piston rod in a downward direction, while when the foot lever 47 is released the weight of the valve 42 and valve stem 43, together with the action of the compressed fluid exerted thereon, will operate to close the communication between said pipes and permit the escape of air in the pipe 35 through the annular chamber 51 and vent 52 to the atmosphere.

It will be apparent to one skilled in the art that if no resilient means be provider to cushion the strokes of the piston rod 27, the door-operating levers would be actuated to move the fire. doors into violent contact with each other when closing, and subject them to violent shocks when opening, therc by causing great danger of breakage of the parts of the mechanism and rendering the operation of the device very noisy and troublesome. I overcome this objectionable feature on the upward stroke of the piston .rod and the corresponding closing movement of the doors, by locating the port 40 a considerable distance below the upper extremity of the chamber at, so that upon the upward stroke of the piston 29, the major portion of the compressed fluid within said chamber above said piston will pass freely through theport 40, check valve 39, pipe 35, annular chamber 51, and vent 52 to the atmosphere. After a portion of the piston 29 has passed and closed the port 40. the remainder of the compressed fluid within the chamber 24;, above the piston 29, will be trapped and afford a cushion. for the pi 'stons and piston rod while they are nearing the upper limits of their strokes. It will be apparent that the upward movement of the piston 29 will be retarded as soon as the port 40 is closed and to permit a further gradual upward movement of the piston 29 and to prevent a degree of compression of the fluid above the. piston which would limit the movement of the piston 29 before it reaches the upper limit of its proper stroke, I provide a vent 53, of very small diameter, in the wall of the check valve 37, in order to permit a restricted outflow of fluid from the upper part of the chamber 24 during the latter portion of the upward stroke of the piston 29. This vent 53 permits a restricted flow of fluid from the chamber 24 during the latter portion of the upward stroke in such a manner that after the piston 29 is retarded upon passing the port 40, it moves relatively slowly until it reaches its uppermost position, being very effectively cushioned during such movement by the fluid above the piston. From the foregoing description it will be understood that the doors have a relatively rapid movement during the first and major portion of the closing operation and that they move relatively slowly and are effectively cushioned during the latter and final stages of the closing operation.

The task of cushioning the doors and cooperating mechanism during the final period of the opening movement thereof has hitherto presented great difficulty, but 1- accomplish this result very effectively in the manner hereinafter set forth. The wall of the lower chamber of the cylinder 22 is provided a short distance above the lower end thereof with an inwardly opening check valve 5 1 which communicates with the chamber 23 by means of the port 55 provided in the wall of said chamber, From the foregoing description taken with the v drawings it will be apparentthat as the piston 28 moves upwardly the valve 54 will open and atmospheric air will be drawn into the chamber 23 in amount equal to the chamber content below said piston. It is this atmospheric air drawn into the chamber which i l efiectively employ for cushioning the piston 28 as it nears the limit of its downward stroke. 7

In the earlier device, above referred to, an inlet valve is also employed for permitting atmospheric air to be drawn into the lower chamber of the cylinder on the rip-stroke of the lower piston, but there is also provided in the upperpart of the inlet valve a bleed opening which provides a communication from the interior of the lower chamher to the atmosphere when the inlet valve is closed upon the down stroke. In the prior device the bearing of the piston rod at the lower end of the cylinder is packed with as .bestos, waste or other soft material for the intended .purpose of insuring an air-tight joint.

From the patent of the'earlier device it will be apparent that said device is operated with the idea ofpermitting the air beneath the lower piston to escape on the downstroke thereof through the bleed opening, and then entrapping a small amount of air below the inlet valve, which air is intended to cushion the opening movement of the doors. It has been found, however,that the prior structure does not properly and efficiently cushion the doors in their opening movement, owing to the impossibility of keeping the soft packing atthe lower end of the chamber sufiiciently tight to prevent leakage and preserve a cushioning effect, and to the increased difficulty introduced by the escape of a large volume of the atmospheric air in the lower chamber of the cylinder through the bleed opening.

The difficulty with the earlier device referred to could not be remedied by raising the port, leading from the lower chamber to the inlet valve, to a position farther from the lower end of the chamber .in order to entrap and cushion a larger amount of air, for the reason that the necessary stroke of the piston would in that event carry the lower piston lower than the bleed opening and thereby permit .the compressed fluid above the lower piston to escape to the atmosphere. It was also impossible toovercome the difliculty by simply eliminating the port leading from the chamber to the inlet valve, because it is necessary to provide means whereby air may freely enter the space below the lower piston on the upthereof, for otherwise a partial vacuum would be introduced below the lower piston on the up-stroke thereof which would produce a violent action of the moving parts on the ensuing down-stroke, and which would, of course, prevent a supply of air from being drawn into the chamber below the piston to act as a cushion on the ensuing down-stroke.

I have found that the difficulties encountered in the use of the earlier device may be effectively remedied and overcome by substituting an improved metallic packing for the asbestos or other soft packing employed in said earlier device, andiby eliminating altogether the bleed opening of that structure. Referring to the drawings accompanying this application, it will be seen that I have providedthe cylinder head 26 with a packing chamber 56 surrounding the piston rod 27 and having an annular shoulder'56' at the upper extremity thereof. Adjacent the lower end of the chamber 56 there ,isrlocateda metallic packing ring 57 which is adapted to closelyfit the piston rod and which is provided with preferably twoinclinedslits .57 extending completely through one wall thereof to permit a circumferential or radial compression of the ring for the purpose of causing the same tomore closely engage the piston rod. The outer side of the packing ring 57 is in the form of an inverted truncated cone having an inclined annular wedging surface 57 which is adapted to coact with a correspondingly inclined inner annular surface 58 formed on the follower 58, formed of brass or the like, which seats within and closely fits the lower end of the packing chamber to close the same, being provided with an annular shoulder 58 which abuts against the lower end of the chamber wall. The packing follower 58 is retained in position by an internally threaded packing nut 59 whichengages a correspondingly threaded portion of the wall of the packing chamber. A washer 6O seatsagainst the shoulder 56 of the packing chamber and a strong coiled spring 61 abuts against said washer and seats at its lower endon the upper annular surfaceof the packing ring 57 thereby tending to pro 'ect the packing ring 57 downwardly within the follower 58 and causing the annular sur face 57 to tightly grip the annular surface 58 while at the same time causing a radial compression of the packing ring whereby said ring very tightly engages the piston rod 27. As the coil spring 61 presses the transversely slitpacking ring 57 downwardly the inclined surfaces of said slits, which are constantly in contact, will slide or ride on each other, tending to distort the ring into the form of a spiral, and thereby permitting a radial compression of said ring as it wedges within the follower. In this manner a metal to metal closure is provided throughout the parts of the packing joint, even after wear is taken up. The amount of air leakage through such a metal to metal joint has been found to accomplish a more efficient cushioning in devices of this character than any other means. It will be seen that by this construction a packing joint is provided, which is durable and constant in action, and not subject to the rapid wear which permitted too rapid an escape of air in the previous devices.

The cylinder head 26 has an air-tight engagement with the cylinder walls and, with the bleed opening of the device previously referred to eliminated, there is apparently no means forair to escape from the chamber 23 below the piston .28 after having been drawn in through the valve 54; but ,I have found that the above described packing even when constructed with the utmost precision, will not be absolutetly tight against comparatively high pressures, and this slight degree ofimperfection in the metallic packing cooperates with the other elements of thestructure to produce the desired cushloning effect during the latter portion of the clown-stroke of the piston.

As above constructed, the operation of the device is as follows: During the up-stroke of the piston 28 the atmospheric air flows in through the inwardly opening check valve 54 in amount equal to the chamber content below the piston 28, and thereafter upon the beginning of the down-stroke of the piston and piston red, the check valve 54; closes, thereby entrapping all of the air within the chamber 23 below the piston 28 at the beginning of the down-stroke. As the downward stroke of the piston continues, the air beneath said piston, whicl' at the outset was at atmospheric pressure, is compressed and cannot escape from the chamber until the piston has moved in its downward stroke to a point where the en trapped air is compressed to such a point that it may escape through the metallic packing. The air in the chamber 23 below the piston 28 will, in compressing, follow the well known laws for the compression of gases and will, therefore. permit a relatively rapid movement of the piston and piston rod during the early and major portion of the downward stroke, but as the piston approaches the lower end of the cylinder the degree of compression will increase rapidly, thus causing the piston and piston rod to be retarded. As above stated, the compresed air below the piston 28 will begin to escape through the metallic packing when the degree of compression has reached a sufficiently high value and this escape of air will permit a relatively slow and gradual movement of the piston during the latter portion of its stroke, the piston being eventually brought to rest when, notwithstanding the escape of the entrapped air through the packing, the degree of compression of the entrapped air below the piston 28 is substantially equal to the pressure of the main fluid supply above the piston 28.

From the foregoing description it will be apparent that the piston and the fire doors operatively connected therewith will have a relatively rapid movement during the first and major portion of the opening op eration, and that the movement thereof will be retarded during the latter portion of the opening movement so as to produce the gradual and slow movement of the doors as they near the limits of their open positions. Upon the succeeding up-stroke of the piston 28 the valve 54: will open and admit atmospheric air to the chamber 23 below the piston 28 when the upward stroke of the piston has reduced the pressure below the piston. to a point below atmospheric pressure. In this way the air supply beneath the piston is positively and quickly replenished. As previously explained, if no inlet valve were provided corresponding to the inlet valve 5 1:, a partial vacuum would be established in the chamber 28 upon the up-stroke of the piston for the reason that we have found in practice that the effective passage of air through the metallic packing takes place only under comparatively high presure, as during the latter portion or the down-stroke of the piston. i a hatever inflow of air there may be through the metallic packing upon the Lip-stroke of the piston, is insufficient to replenish the supply of cushioning air beneath said biston.

The prior device above referred to depends for the cushioning of the doors during the latter port-ion of their opening movement, upon absolutely entrapping a certain body of air at the end of the opening movement and providing the cushioning effect by means of this entrapped air, the object in the prior construction being to prevent the escape of the entrapped air during the cushioning period by an absolutely tight packing around the piston rod. The theory of operation of my improved structure is not at any time to absolutely entrap a body of air in an air-tight space as in the prior device, but to compress all of the air beneath the piston at the beginning of the opening stroke, and to rely for the cushioning effect upon'such compression and the escape of a part of the resulting compressed air beneath the piston through the metallic packing when the pressure has been built up to such a point as to cause a restricted flow through the packing.

While the operation of the device is doubtless clear from the foregoing description, it may be summarized as follows:

When the operator is ready to introduce a quantity of fuel into the fire-box, he places his footupon the foot lever 47, causing the short arm 47 to move the valve 42 upwardly from its seat, whereupon the compressed air will pass from the pipe 81 through the foot valve 3%, pipe 35, branch pipe 36 check valve 37, and duct 88 to the upper side of the piston 29, thereby causing said piston and the piston rod 27 to move downwardly in a forward stroke to actuate the door-operating levers and thereby open the doors. It

ill be understood that during such movement the air within the chamber 23 will be compressed so as to provide a cushioning for the moving parts near the limit of their movement, as above described. After he operator has thrown the fuel into the furnace. he removes his foot from the foot lever, whereupon the valve 42 falls by gravity and by virtue of the influence of the compressed fluid in the chamber into its normal closed position. Thereupon, the effectire pressure tending to move the piston rod 27 will he the difference between the pressures exerted on the inner adjacent faces of the upper and lower pistons 29 and 28, which, of'course, will cause the piston rod to make a return stroke, expelling the compressed air from above piston 29 through the port 40, check valve 39, branch 36 pipe 35, annular chamber 51, and port 52 to the atmosphere, until the piston 29 closes the port 40,,after which the air remaining in the chamber 24, above the piston 29, will 10 havea restricted flow through the small vent 53, and thereby provide a cushioning for the piston 29 during the upper limit of its travel. At the same time atmospheric air will'be drawn in through the check valve into the chamber 23 beneath the piston 28. By means of my device operating as above described, it will be apparent that I have provided an efiicient and quick-acting means for opening the fire doors of a fire box in as noiseless a manner as possible without causing undue shocks or strains upon the doors or other moving parts near the limits of their respective paths of travel. IVhile I' have described a specific embodi- 25 ment' of my invention, and have illustrated the same in connection with the fire-box of a locomotive, it will be understood that my invention may be used in other connections and may itself partake of widely different forms without departing from the spirit thereof as embodied in the appended claims. lVh-at I claim is: 1. In a fluid-actuated operating mechanism, a cylinder, a piston in said cylinder, a piston rod upon which said piston is mounted, a metallic packing in the end of said cylinder around said piston rod, fluid pres sure means for moving said piston towards said metallic packing, means to produce a reverse stroke, and an inlet valve to permit atmospheric air to flow into the chamber on the side of said piston adjacent said packing during said reverse stroke, said packing permitting the escape of air therethrough under a relatively high pressure, said cylinder being constructed to prevent the escape of air from the chamber on the side or" said piston adjacent said packing except through said packing.

2. In a fluid actuated operating mechanism, a differential cylinder, a plurality of pistons in said cylinder, a piston rod upon which said pistons are mounted, a metallic packing in one end of said cylinder and surrounding said rod, fluid pressure operating upon one of said pistons for forcing both of said pistons towards said metallic packing, means for positively moving said pistons in a reverse direction, and an inlet valve located between one of said pistons and said Inetallic packing for admitting atmospheric air to said cylinder during said reverse stroke, said packing being adapted to permit the gradual escape of air between the packing and said adjacentpiston upon a relatively high pressure caused by the movement of said piston towards said packing, said cylinder being constructed to prevent the escape of air from the chamber on the side of said piston adjacent said packing except through said packing.

In testimony whereof, I have subscribed my name.

JAY G. ROBINSON.

lVitnesses WVALTER A. Scorn GLEN E. SMITH.

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