US840877A

US840877A - Fluid-actuated cushioned hoist.

Info

Publication number: US840877A
Authority: US
Inventors: George F Steedman
Original assignee: Individual
Current assignee: Individual
Priority date: 1905-12-04
Filing date: 1905-12-04
Publication date: 1907-01-08
Anticipated expiration: 1924-01-08

Description

PATENTED JAN. 8, 1907.

G. F. STEEDMAN.

FLUID ACTUATED GUSHIONED HOIST.

APPLICATION FILED DBO. 4, 1905.

3 SHEETS-SHEET 1.

No. 840,877. PATENTED JAN. 8, 1907.

G. P. STEBDMAN.

FLUID AGTUATED CUSHIONED HOIST. APPLICATION FILED B11014, 1905.

3 SHEETS-SHEET Z.

PATENTED JAN. 8, 1907.

G. P. STEEDMAN. FLUID AGTUATED GUSHIONED HOIST.

APPLICATION FILED DEC. 4, 1905.

3 SHEETS-SHEET 3.

W062i? Sbeedman George] @zr zeaaea,

GEORGE F..STEEDMA1\I, OF ST. LOUIS, MISSOURI. FLU lD-ACTUATED CUSHlONED .HOIST.

Specification of Letters Patent.

Patented Jan. 8, 1907} Application filed December 4,1905. Serial No 290,180.

To all whom it may concern:

Be it known that I, GEORGE F. STEEDMAN, a citizenof the United States, residing at St. Louis, Missouri, have invented a certain new and useful Improvement in Fluid-Actuated CushionedHoists, of which the following is a full, clear, and exact description, such as will enable others skilled in the art to which it appcrtains to make and use the same, reference being had to the accompanying draw ings, forming part of this specification, in whic .Figure 1 is a diagrammatical view of a single acting regulated cushioned hoist constructed in accordance with my invention. Fig. 2 is a diagrammatical view of a doubleacting regulated cushioned hoist. Fig. 3 is a diagrammatical view of a balanced regulated cushioned hoist. Fig. 4 is 'a fragmentary side elevational view of a portion of the cylinder, showing the specific form of regulating device, and Fig. 5 is a vertical longitudina sectional view through the regulating-device casing.

' This invention relates to fluid-actuated hoists in which a cylinder is employed for containing a piston to be actuated by a suitable fluid, preferably air.

.The object of the invention is to construct a fluid-actuated hoist the speed of whose piston under no load, as Well asunder full load,

may be regulated independently of the operating-valve and in such a manner that the piston wil automatically slow down and gradually come to rest at the extremities of its stroke independently of the. manipulation of the regulating-valve.

Broadly stated, the invention is carried out by means of a speed-regulating device, as illustrated in acompanion application executed by me of even date herewith and given Serial No. 290,179, the characteristic feature of this invention residing in the addition of an air-cushioning device at the ends of the cylinder and means for regulating the cushion.

As illustrating the principle of my invention I'have shownin ing contained therein a piston 2, with an outwardly-projecting stem 3. A supply-tube 4 a three-way valve 5, which may be operated to direct a flow of fluid, such as air, into one end of the cylinder throu 'hthe inlet-tube 6, or it may be turned, as in icated' in Fig. 1, to exhaust from the end of the cylinder, as the case may require.

Fig. 1 a cylinder 1, hav-- der is a loop consisting of two branches 7 and 8. The branch 7 is provided with a checkvalve 9 of ordinary construction and is so arranged that it is capable of opening only to admit the air into the cylinder 1 by flowin in the direction indicated by the arrow.

10 is arranged in the branch 8, and this checkvalve is permitted to open only when the fluid flows in the direction indicated by the arrow adjacent the valve 10 and out through the exhaust, as will be presently explained.

branches 7 and 8, which may be manipulate ings in either of the branches 7 and 8-, so as throng tube 4 is a ported tube 13, having an inwardly-opening check-valve 14 therein, and in the same end of the cylinder is illustrated a valved tube 15. In communication wit the inlet-openings of the cylinder 1 and the tube 6 is a branch 16, having a regulatingvalve 17 therein, which is adapted to be regulated so as to govern the volume of air passing through the branch 16, which branch 16 is what might be termed a cushion-control. 8 designates an exhaust-tube near the upper end of the cylinder and correspondsto the branch 8, which tube 8 is provided with a regulating-valve 10 and an outwardly-opening check-valve 12*.

The operation of the device in the form illustrated in Fig. 1 is as follows: Suppose the valve-5 is turned to admit air through the branches 7 and. 16 into the cylinder. The opening in

valves

15 and 17 is so small that it may be disregarded except for its cushion i ing function.

branch 8 to act upon der, for the reason that the outwardly-opening check-valve would prevent it; but it must pass through the branch 7 into the cylinder, so as to actuate the piston within the cylinder to move it from the end adjacent the branch 7 toward the opposite end. The speed of hoisting or theinward motion of the piston will depend upon the load-to be lifted and the size of the openings "made by the valves 1]. and 10. For the maximum load on the piston-rod 3 the valve 11 will be adjusted so as to give proper speed, the valve 1 10 meantime being fully open. For the 11 and 12 designate cocks in the respective .so as to regulate the size of either of the open- In the end of the cylinder opposite the Air cannot pass through the Interposed between the tube 4 and the cylin- I similar but oppositely-opening check-valve to control the amount of air flowing there the piston in the cylinwith the exhaust-port 19 in the valve-casing,

' between the loop and the supply-pipe 4. In

- the branch 16 is in communication minimum load on rod 3 the adjustment of the valve 11 will be unchanged, the speed of the hoist being regulated by the valve 10. By a harmonious adjustment of valves 11 and 10 the speed of hoisting is made approximately uniform irrespective of the load. It is to be understood that in the operation the check-

valves

10 and 14 cause the tube 13 and branch 8 to be temporarily inoperative; also, that the valve 5 is in a wide-open admitting position. It will be assumed that the cylinder is arranged in a vertical plane and that the operation just described has resulted in raising the piston. Now if it is desired to lower the piston or to permit it to descend, the valve 5 will be. 0 erated so that its port 18 will register with an exhaust-port 19 in its casing ang' with the loop formed by the-branches 7 an 8.

In order to cause the port 18 to register it will be necessary to cut off communication this position of the valve the fluid can pass from the bottom of the cylinder through the branch 8 and through the valve-plug and then to atmosphere. The exhaustlon of the cylinder through the branch Swill continue until the lower end of the piston 2 reaches a position to register with the branch 8, when the exhaust through the branch 8 will be promptly cut off. When it is considered that the branch 8 is positioned a short distance from the end of the cylinder, it will be appreciated that a volume of air will still remain in the cylinder e ual to the inner area of the cylinder-times t e distance from the lower face of the piston to the inner face of the lower end of the'cylinder. This volume of air will represent the cushion, and as it cannot exhaust through the branch 8 (on account of the fact that communication with the branch has been cut ofl) and as it cannot exhaust through the branch 7 it must exhaust through the branch tube 16. Now as with the pipe 6 and with the ort 19 of :the valve-casing the speed at which the cushion is destroyed will depend upon the adjustment of i which the piston travels it will the valve. 17, which controls the size of the opening through which the air will pass.

, In ascending the air will exhaust'through the pi e 8 until communication between the cylin er and said pipe is cut off in the same manner as has been described in connection with the branch 8, and as soon as communi cation is cut Ofl" inthe branch 8 a cushion will be formed at the upper end of the cylinder, the air forming the cushion exhausting .Fig. 1.

through the valved tube 15.

From the foregoing it will be seen that the speed intermediate the ends of the cylinder I may be controlled to suit the purposes of the operator, but irrespective of the speed atl slacken and gradually come to a stop before reaching the end of its strok 4 In actual practice I have demonstrated that this stoping will be so gradual as to be practically ee from any jar or objectionable vibration which under ordinary circumstances might be communicated to the load carried by the piston-stem 3.

In the form of hoist just described, which I designate as single-acting, the actuatin fluid enters the lower or piston-rod end 0 the cylinder only.

From the foregoing description it will be seen that in general I regulate the speed of hoisting and lowering the variable load by providing an adjustable force resisted by an adjustable resistance thereto, which in practice I have found to produce. regulation many times more efiective than the regulation' of either separately, and combined with the many advantages resulting therefrom I apply a regulating-cushiondesigned to prevent sudden jars or shocks from being communicated to the load bythe either extremity of its stroke.

In Fig. 2 I have illustrated what I designate as a double-acting hoist. The difference between the forms illustrated in Figs. 1 and 2 is that in Fig. 1 the piston is ermitted to gravitate from the upper to the ower end of the cylinder, while in Fig. 2 air is admitted at the respective ends of the 'cylinder' at different times, and the pipe 6 is illustrated as being in communication with the four-way valve 20, the casing of which is also in communication with the supplypipe 4. A pipe 6 is in communication with the valve-casing, and instead of the valved tubes 8", 13, and '15 I substitute a duplicate arrangement of tubes and valves similar to that described for the lower portion of the cylinder shown in Fig. 1, th which is so similar further explanation.

In Fig; which I term a balanced-cushioned hoist. The cylinder, piston, and other accessories, including the tubes, valves, &c., are substantially the same as those illustrated in 2, with the exception that the tube 6 is in communication with a reservoir 22, which rese operation of ervoir is also in communication with the tube 6, in the path of which is a three-way valve 5,

similar to the one illustrated in An elevator-car 3 is also illustrated as being adapted to be raised and lowered by. the piston 2 through the medium of the rod 3. In this form (illustrated in Fig. 3) the valve. 5 is shown ina position to rqualize the pressure in all parts of the cylinder, and

this will be the case, because, although the tank 22 is under pressure, the inlet-openings to both ends of the cylinder are-in commuautomatically thereto. as not to need the force or the resistance- 3 I have illustrated a construction valve-seats 25-and 26, on

spectively.

-phere, and communication nication with the tank through the respective pipes 6 and 6", and the same pressure will be exerted on both sides of the piston 2. However, the area of the upper face of the piston a ainst which the pressure will be exerted will be slightly in excess of the resisting area of the lower face of the piston, due to the fact that the piston-rod is connected to the lower face of the piston. .In other words, the resisti area of the upper face of the piston will e equal to the resisting1 area of the lower face of the piston plus t ecrosssectional area of the piston-rod. It therefore follows that if the same pressure exists in the cylinder and a greater area of resistance exists on the upper face of the piston the tendency of the piston will be to descend, even when no loa 1s carried by the rod, and this tendency to descend is augmented by.the weight of the rod, and-additionally so by any weight carried by the rod. Thus if the valve 5 is in the position indicated in Fig. 3 and the piston happened to be at the upper end inder it would gravitate toward the bottom in an obvious manner. When it would be desirable to hoist the load, the valve 5 would be operated to throw the portof the valve into communication with the exhaustport of the casing, so that the air could exaust from the top of the c%linder to atmosetween the ipe (i and the reservoir 22 would be cut oii so that all of the pressure in the tank would be exerted against the lower face of the iston,

so as to raise it. The cushioning of t e piston, however, would in no ,wise be afiected by this operation.

In Figs. 4 and 5 I have illustrated a par.- ticular form of regulating device in which the inlet and outlet valves, together with the cushioning device, are all arranged in a common casing. In order to disclose the application of the device illustrated in Figs. 4 and 5 as applied to the cylinder and in lieu of the branch ipes and valves heretofore described, I have esignated the inlet-pipe 23, which is in communication with a casm 24, having Whic are checkvalves 27 and 28, communication between the

tubes

29 and 23 and the oppositely-openingcheck-valve 28 permitting communication between the

tubes

30 and 23. Springs 31' and 32 are seated on the refipective check-valves and bear agamst stu ng-

boxes

33 and 34, .re-

These springs have. a tendency to maintain the valves on their seats and to reseat them when they have been unseated.

Passing through the stuffing-boxes are adjusting-

screws

35 and 36,'wh1ch serve as regulating-devices for regulating the distance I the check-valves are capa le of moving ofl their seats, and thereby regulating the size of the passage of communication between the on both sides of the piston of the cyl-' is claimed as new,

tubes

29 and 30 with the tube 2.3. Adjacent to the tube 30 is a threaded port 37, with which a threaded regulating device or screw 38 is adapted to coact to regulate the cushion. The tube 29 being in communication with the cylinder at a point a slight distance from the end thereof and the tube 30 being in communication with the cylinder at the extremity thereof, the operation will be as follows: The air will be admitted through the tube 23 and will ass up through the opening normally closed l iy the valve 28 into the tube 30, and thence to the cylinder. If the air is admitted to the other end of the cylinder, the piston will be moved in the direction of the arrow and the air will exhaust through the pipe 29, through the openi g normally closed d by the valve 27, and then mto the pipe 23 to the exhaust. As soon as the piston reaches a point in the cylinder opposite the opening of the ipe 29 communication with the pipe 29 will be cut oil, and the cushioned air between the piston and the end of the'cylinder will be forced through the pipe 30 and the pressure will have a tendency to maintain the valve 28 on its seat, so its only escape can be through the opening 37. lating device 38 is controllable to regulate the size of the opening 37, the cushion maybe regulated.

In describing the above invention I have urposely referred to each part and described 1t specifically, so that the operations of the various forms might be easily understood, and the cylinders have been described as being of the vertical type, in which the piston has a descending and ascending movement. However, I reserve the right to arrange the cylinders horizontally or at any other angle, if desired, and whenever the terms vertica ascendin and, descending are employed I would have it understood that they are not to be construed literally, but are used merely for the sake of distinguishing one movement from the other.

Having thus described the invention, what and desired to be secured by Letters Patent, i

1. In a device-of the class described, the combination of a cylinder, a piston therein, an inletipe in communication with the end of the cy linder, an exhaust-pipe intermediate.

As the reguthe ends of the cylinder and in commumcation therewith,- the communication being cut ofl by the piston when the piston is adj aeont to the exhaust-pipe, means for exhausting the fluid existing between the end of the cylinder and the piston after the communication with theexhaust-pipe has been cut oil, and a regulating. device in said last-named means; su stantially as described.

2. In a device of the class described, the combination of a cylinder, a piston therein, a-n operating-valve, a tubularconnection between the valve and the cylinder, said tubular connection being divided into connectingpassages, means for cutting off communica the passages when the other passage is open,

said piston being movable into positionto cut ofi communicatlon' between the other passage and the cylinder, a secondary exhausting means communicatin with the end' of the cylinder and constructed so as to continue to exhaust after communication with said other passage has been out off, whereby a cushion may be rovided for the piston near the end of the cy inder due to the volume of air existing between the end of the cylinder and the piston, and means in the secondary exhaust for regulating the exhaust from said cylinder; substantially as described.

4. In a device of the class described, the combination of a cylinder, a piston therein, an operating-valve, a tubular connection between the valve and the cylinder, said tubular connection being divided into connectingpassages, means for automatically cutting ofl communication between the cylinder and valve in one of the passa es when the other passage is open, and a cushioning exhausting device in communication with the end of the cylinder; substantially as described.

5. In a device of the class described, the combination of a cylinder, a piston therein, an operating-valve, a tubular connection between the valve and the cylinder, said tubular connection being divided into connectin passages, oppositely-openin check-valves 1n said passages, and a valvetfexhaust-port in communication with the end of said cylinder;

' substantially as described.

6. In a device of the class described, the combination of a cylinder, a piston therein, an operating-valve, a tubular connection between the valve and the cylinder, said tubular connection being divided into connectingassages, a check-valve in one passage openmg toward the'cylinder, a check-valve in the opposite passage opening toward the operating-valve, and an exhaust-port in communication with the end of the cylinder and permitting exhaust of the fluid from the cylinder when both cheok-valves'are closed; substantially as described.

7. In a device of the class described, the combination of a cylinder, 9: piston therein, an operating-valve, a tubular connection between the valve and the cylinder, said tubular connectionhaving independent connecting-ports, means for re lating the size of each port, means for cutting ofi communication between both ports, and an exhaustport in communication with the cylinder which is capable of continuing the exhaust when communication between both orts and the cylinder is cut off; substantial described.

8. In a device of the class described, the combination of a cylinder, a piston therein, anoperating-valve, a tubular connection between the valve and the cylinder, said tubular connection being divided into independent connecting-passages, oppositely-opening check-valves in the respective passages, means for regulating the size of each passage, and a valved exhaust in communicatlon with one end of the cylinder; substantially as described.

9.'In a device of the class described, the combination of a cylinder, a piston therein, an operating-valve, a tubular connection between the valve and the cylinder, said tubular connection being divided into se arate branches one of-which is a supply to t e cylinder and the other an exhaust, means for automatically closing one branch when the other is open, means for regulating the size of the ort in each branch, the piston being movablia into position for closin the open branch whereby both branches wil be closed, and an exhaust-port through which the air may be continued to exhaust when both branches are closed; substantially as described.

10.' In a device of the class described, the combination of a cylinder, a piston therein,

an operating valve, a tubular connection between the valve and the cylinder, said tubular connection being ,divided into so arate branches, one of which is a supply to t e cylinder and the other an exhaust, the exhaust branch bein adapted to be closed by the movement 0 the piston, anda secondary exhaust in communication withthe cylinder and operable after the exhaust branch is closed; substantially as described. a

11. A regulating device of the class described having a port adapted to alternately receive and discharge a fluid, said regulating device having an'exhaust-port 1n communication with said first-named port through which the fluid will flow in exhausting, all other sources of communication with said first-mentioned port being closed; substan tially as described.

12. A regulating device of the class described comprising a casing, supply and exhaust ports in communication with said casing, a third port in communication with both said first-mentioned ports, and means for valving the first-mentioned ports, said casing having a port in communication with said. supply-port and -to one side of the valved portion of said port; substantially as described.

13. The combination with a cylinder, and a source of fluid-supply, a piston in said cylinder, a supplytube in communication with said cylinder, an exhaust-tube in communication with said cylinder, a regulating device, the casing of which is in communication with both tubes, oppositely-opening check valves in said regulating device affording communication between one of said tubes and the source of supply when the other of said tubes is closed, said casing having an exhaust-port between the sulpply-port valve and the discharge end of t e supply-tube; substantially as described. v i

14. The combination with a cylinder, and a source of fluid-supply, a piston in said cylinder, a supply-tube in communication with said cylinder, an exhaust-tube in communication with said linder, a regulating device, the casing of whic is in communication with both tubes, oppositely-opening check-valves exhaustin tubes is close" said casing exhaust-port between the suIpply-port valve fluid through the port, said means device affording commumof said tubes and the the other of said having a valved in said regulating cation between one source of sup ly'when and the dischar e end of t e supply-tube; substantially as described.

15. The combination with a cylinder and piston therein and a source of fluid-supply, of an operating-valve capable of admittmg'or the operating fluid from said cylinder, a tu ular port connecting said operating-valve with thecylinder, regulating means in said port, for controlling the admission of being independent of the operating-valve, re lating means in said port independent of t e 0 erating-valve for eontrollin the egress of fluid thI'OII 'h said port, and a uid cushion at the end oi said cylinder connected to said port through a passage in which is a means for re lating the egress of su stantially as described.

16. The combination with a cylinder havin a port at each end, and a piston in said cy inder and ,a source of fluid-supply, of an operating-valve capable of admitting or exhausting the operating fluid from said cylinder, a tubular ort connecting said operating-valve with t e cylinder, regulating means in said port, for controlling the admission of fluid through the port, said means being independent of the operating-valve, re ulating means in said port independentof the operatini-lyalve for controlling the egress of fluid tough said port, and a fluid cushion at the end of said cylinder connected to said ort through a passage in which is a means or regulating the egress of fluid/to said port; substantially as described.

17. The combination of a cushioned c linder with piston and-operating-valve, o1 a port with with chec fluid to said port;-

port with check-valve therein which can be used for exhausting only,

a port with checkvalve therein which can be used for admis-.

sion only, and a port to dissipate the cushion; I

substantially as described.

18. The combination of a cushioned cylinder with piston and operating-valve, of a therein arranged for exhaustin fluid from cylinder only a port with chec -valve and regulatin -valve therein arranged for admitting fluif to the cylinder only, and a port check-valve and regulating-valve with regulating-valve thereinto control the cushion; substantially as described.

19. The combination of a cushioned cylinder and piston therein, a fluid cushion at each end of the cylinder, a source of fluidpressure supply, an operating-valve connectedby a port to one endof said cylinder, an exhaust connection with check-valve and regulating means therein between said port and cylinder, an admission connection with check-valve and regulating means therein between said port and cylinder, and a connection with regulating means therein between the cylinder and port arranged to regulate the dissipation of the cushion; substantially as described.

20. The combination with a cushioned cylinder and piston therein, a fluid cushion at each end of the c linder, and a source of fluid-pressure supp y, of an operating-valve connected by a port to one end of sai cylinder, an exhaust connection with check-valve and regulating means therein between said. port and cylinder, an admission connection -valve and regulatingmmeans therein between said port and cy der, a connection with regulating means therein between the cylinder and port arranged to regulate the dissipation of the cushion; means for regulating the. escape of air from the opposite end of the cylinder to the atmosphere, and a means'for re ating the-dissipation of the cushion at the ast-mentioned end of the cylinder; substantially as described.

21. The combination with a double-acting cushioned cylinder and piston therein and a source of fluid-pressure supply, of an operating-valve connected to said source and to 'both ends of the cylinder by ports, and reguin; substantially as described.

, 23. In a means for regulating a cushioned cylinder of the class described, a casing with an exhaust connection, and an admission cylinder but preventin admission of air to same, a means for regu ating the area of the exhaust-port; a port in said caslng between the admlsslon connection and operat1ng Yvalve connection, a check-valve in saidport permitting the admission of air to the cylinnecting the admission connection to the operating-valve connection, and a means in said secondary port for regulating the area of said I "port; substantially as described.

. nection 23, an exhaust connection 29, and an admission connection 30, a port in said casmaximum opening of said check-valve,

port said casing leading from the operatmg-valve connection 23 to admission connection 30, a check-valve 28 in said port, a

means for limiting the maximum opening of v said check-valve, and a secondary port be der but preventing the exhaust of air from same, a means for regulating the area of the j, admission-passage, a secondary

port contween connections

23 and 30, with a means for adjusting the area of said secondary port; substantially as described.

In testimony whereof I hereunto affix my signature, in the presence of two Witnesses, this 21st day of November, 1905.

GEORGE FL STEEDMAN.