US2187513A - Hydraulic operating device - Google Patents

Description

Jan. 16, 1940. J, EVANS 2,187,513

HYDRAULI C OPERATING DEVI CE Filed Aug. 2, 19:55 3 Shets-Sheet 1 I N VEN TOR. afkmgs M 21 4/75.

A TTORN E Y6.

"Jan. 16, 1940. J, EVANS 2,187,513

HYDRAULI C OPERATING DEVICE Filed Aug. 2, 1935 3 Sheets-$heet 2 i I /A0 f l 1 a INVENTOR. Q? James M 51 4775.

BY W A TTORNEYS.

Jan. 16, 1940. EVANS 2,187,513

HYDRAULI C OPERATING DEVICE Filed Aug. 2, 1935 3 Sheets-Sheet 3 INVENTOR. i /J2 m6's A4 51 4276.

A TTORNEY-S.

Patented Jan. 16, 1940 UNITED STATES PATENT OFFICE HYDRAULIC OPERATING DEVICE Tennessee Application August 2,

4 Claims.

The present invention relates to protective devices for use at road crossings and the like, and particularly to hydraulic operating devices for controlling the operation of such protective de- 5 vices, as well as of other devices.

It is an object of the present invention to provide a hydraulic ram in which the movement of the ram may be automatically retarded or interrupted at any adjustably predetermined 10 point in the path of movement thereof.

It is also an object of the present invention to provide a hydraulic ram in which the duration of the interruption of the ram movement may be conveniently adjusted.

It is also an object of the present invention to provide a hydraulic ram embodying an auxiliary chamber to control the interruption of the ram movement at the intermediate stage. a It is also an object of the present invention to provide a hydraulic ram of the above character embodying an intermediate adjustable sleeve to render the auxiliary chamber effective and control the point in the path of movement of the ram at which the retardation orv interruption in the movement thereof occurs.

It is-also an object of the present invention to provide a protective device embodying main and auxiliary hydraulic actuating rams, in which the 30 movement of the auxiliary ram piston automatically actuates a holding device to positively retain the protective device in an extended or operative position.

Other objects and advantages of the present invention appear in the following description and in the appended claims.

In the drawings:

Figure 1 is a schematic view of a crossing barrier and operating mechanism therefor embodying the present invention;

Fig. 2 is a view in vertical section, taken on the line 2-2 of Fig. 1;

Fig. 3 is a view in horizontal section of an adjusting member, taken on the line 3-3 of Fig. 4 is a view in horizontal section of the adjusting sleeve, taken on the line 4-4 of Fig. 2;

Fig. 5 is a view in vertical section of a modified embodiment of the present invention;

in Fig. 6 is a fragmentary view in side elevation,

taken along the line 6-6 of Fig. 5;

Fig. '7 is a fragmentary view in horizontal sec tion, taken along the line 1-1 of Fig. 5;

Fig. 8 is a. view in vertical section of a second :5 modification of the present invention;

1935, Serial No. 34,321

(Cl. (so-52) Fig. 9 is a fragmentary view in vertical section, taken along the line 99 of Fig. 8;

Fig. 10 is a view in elevation of a hydraulically actuated protective device, embodying a mechanical holding means to retain the protective device in an extended or operative position; and

Fig. 11 is a view in vertical section taken along the line H--H of Fig. 10.

As described more in detail hereinafter, the arrangement comprises generally a crossing barrier, which normally occupies the illustrated retracted position, and is connected to the push rod of a hydraulic ram for actuation thereby. The ram may be actuated manually or automatically, and moves the barrier through an initial warning movement, retards or interrupts its motion temporarily, and finally moves it to a final extended position. Thereafter, the ram may be actuated to return the barrier to the initial position.

It will be understood that the illustrated form of barrier is illustrative only, and that any suitable form may be substituted therefor and arranged for actuation by the ram in the practice of the present invention. The illustrated form is similar to that disclosed in the co-pending ap-. plication of Glenn W. Goodman, deceased, Serial No. 744,722, filed September 18, 1934., for reissue of Patent No. 1,878,234, and assigned to the same assignee as the present application, and comprises a member pivotally supported in an embedded box, which may be suitably positioned in a roadway.

The hydraulic ram of the present invention embodies many features in common with the hydraulic ram disclosed and claimed in the copending application, now abandoned, filed jointly by the present applicant and S. M. Narnpa, Serial No. 34,320, filed August 2, 1935, and assigned to the same assignee as the present invention. The hydraulic ram disclosed in the latter application embodies mechanism to effect a hesitation in the movement thereof during either the forward or return stroke. Mechanism is also provided to enable the ram to absorb excessive overloads, and to relieve the actuating pressure when the ram is at the upper limit of its travel.

In accordance with the present invention, it is considered desirable to provide for the complete interruption of the movement of the hydraulic ram at any desired intermediate point in its path, although the illustrated mechanism may also be used to effect merely a retardation in the movement. The arrangement is also such that the duration of the retardation or interruption in the ram movement may be conveniently adjusted. In accordance with one modification of the present invention, the hydraulic ram is provided with an intermediate sleeve adjustably positioned to expose a relief port at an intermediate stage of the ram movement. As will be apparent from further description, the size of the port thus exposed determines whether the ram movement shall be merely retarded or shall be entirely interrupted. The exposed port leads to an auxiliary chamber, embodying a movable piston, and normally filled to the normal level thereof. Upon the auxiliarly chamber being filled with the actuating fluid through the relief port, the original rate of ram movement is resumed.

In accordance with a modified embodiment of the present invention, a plurality of independently operable valves are provided to expose a relief port at a predetermined point in the path of movement of the ram. The ports thus exposed lead to the above described auxiliary chamber, which functions as above mentioned to effect the resumption of the original rate of movement.

The auxiliary chamber embodies a spring biased piston, the force of the biasing spring being less than the normal load on the ram. During the period of retarded or interrupted movement, the auxiliary piston is moved against the force of the spring, which serves to restore the piston to an original position upon completion of an operating cycle. The normal position of the piston is adjustable, thus modifying the volume to be filled, and determining the length of the period of retarded or interrupted motion.

In further accordance with the present invention, the piston is arranged to provide holding or retaining mechanism which becomes effective during the extending movement of the guard to positively retain it in the extended position. Preferably, however, and as illustrated, the holding mechanism is ineffective during the initial movement of the guard, so that the latter may be forcibly pushed back against the force of the actuating mechanism, in response, for example, to the passage over it of a vehicle.

In the form illustrated, the holding mechanism comprises a mechanical interlock, composed of a pair of spaced pivotally mounted arms, which may be swung into a position in which they are effective to block and prevent downward and retracing movement of the barrier. The arms are resiliently connected, through a spring, to a member which is actuated by the piston of the auxiliary or retarding cylinders, mentioned above. When such auxiliary piston reaches the upper movement of its stroke, the plunger is engaged thereby and moved upwardly, tending to force the arms into blocking position. This movement is prevented at the time by the formation of the guard itself. At the conclusion of the guard movement, however, the guard moves past the end of the arms, permitting the latter to swing to blocking position under the influence of the previously mentioned spring. The directions of motion of the parts are such that after the arms reach a blocking position, any downward movement exerted thereon by the guard tends to force the arms to a further blocking position, so that the spring and associated parts are required to serve only the function of moving the arms to blocking position.

Referring in detail to Figs. 1 through 4, barrier 20, which normally occupies the illustrated retracted position, is pivotally connected through a crank 22 and clevis 24 to the push rods 28 of a hydraulic ram designated generally 28. Ram 28 is pivotally supported by a lower clevis 88 upon a suitably embedded stationary support 82. As will be understood, upward movement of push rods 28 moves barrier 28 from the full line position to the extreme dotted line position, and, as hereinafter described, the movement thereof may be temporarily interrupted at an intermediate position indicated by the intermediate dotted line.

. Referring to Figs. 2, 3 and 4, the push rods 28 extend through openings 48 formed in the top surface of cylinder 42, and are secured by nuts 44 to a piston head 48, which is slidably fiitted into an inner sleeve 48. Sleeve 48 is of cylindrical cross-section and is rotatably fitted in cylinder 42. As illustrated, a lug 58 prevents upward movement of sleeve 48, and the lower end thereof bears against the base plate 52 of cylinder 42.

As shown in Fig. 3, the upper surface of sleeve 48 is provided with an arcuate slot 84, through which one of the push rods 28 passes, and with an enlarged arcuate opening 88, one side of which is formed as an arcuate rack 88. A pinion 88, fixed On a trunnion 82, meshes with rack 88 and serves to rotate sleeve 48 within cylinder 42 to adjust the hesitation point of piston 48, as described in more detail below. Trunnion 82 passes through an opening formed in the upper surface of cylinder 42 and is normally fixed therein between a lock nut 84 and a collar 88. As will be understood, by relieving lock nut 84, trunnion 82 may be turned by means 01' the head 81, rotating gear 88 and, consequently, rotating sleeve 48 within cylinder 42.

As best shown in Figs. 2 and 4, the side wall of sleeve 48 is provided with a series of openings 10, which are angularly arranged, and may, upon rotation of sleeve 48, be moved into or out of registration with a relief column 12 formed at one side of cylinder 42.

Column 12 communicates through nipple 14 with the interior of an auxiliary chamber 18, which serves to determine the duration in the hesitation of the movement of piston head 48. Chamber I8 is normally entirely filled with fluid, and communicates with the upper portion of chamber 42 through a pipe 18, which extends slightly below the normal fluid level, in sleeve 48. Piston 88 is guided on a column 82 in chamber l6, and is biased to a normal lower position by means of a coil spring 84, seated between the upper surface of chamber I8 and piston 88, but may be moved upwardly within chamber 18 by rotation of a traveling screw 88. Screw 88 passes through an opening formed in the upper surface of chamber 18, is threaded through a plate 88, and is freely supported in a base member 98 secured to the chamber 18. Rotation of screws 88 in one direction draws plate 88 upwardly, the movement thereof being additionally guided by rod 92, which action forces piston head 88 upwardly within chamber 16. Rotation of screw 86 in the opposite direction causes plate 88 to move downwardly, in which event piston head 80 also moves downwardly under the influence or spring 84. Screw 88 may be locked in position by a lock nut 93.

Pump 84, which may be of any suitable type effective to force a fluid in one direction, but adapted when idle to permit a free passage of fluid in the opposite direction, and illustrated asof the radial bladed centrifugal type, is driven by motor 86 through shaft 88, and communicates with the lower portion of cylinder 46 through port I00, and with the upper portion thereof through side ports I02 formed in an inner sleeve I04. As shown, sleeve I04 is tightly fitted within an annular recess I08 formed in the housing of the pump 84, passes through an opening formed in piston 46, and is somewhat freely seated in a recess IIO formed in the under side of the upper end wall of sleeve 48. A plurality of ports I06 provide communication between sleeve I04 and the interior of the pump housing. As will be understood, suitable packing may be interposed between piston 46 and sleeve I04, as well as between sleeve I04 and sleeve 48. Similarly, suitable packing may be interposed between piston head 46 and sleeve 48.

Resilient sleeves II2, secured to push rods 26 engage the upper end wall of sleeve 48 to provide a limit stop for piston 46. The upper end wall of sleeve 48 also serves as a baffle to prevent splashing and foaming of the fluid.

With reference to the operation of the hydraulic ram as a whole, motor 86 may be placed in operation to effect an upward movement of piston head 46. The starting of motor 06 may be effected in any suitable manner, depending upon the use to which the mechanism is to be placed. For example, in connection with the use -..of the mechanism. to actuate crossing guard mechanism as shown in Fig. 1, motor 96 may desirably be automatically placed in operation upon the approach of a vehicle to the associated crossing. The mechanism for initiating the operation of motor 96 forms no part of the present invention, and accordingly has not been illustrated.

Upon being started, motor 86 drives pump 94, the direction of operation thereof being immaterial in view of the illustrated pump construction, causing the latter to draw fluid downwardly through sleeve I04 into the region beneath piston 46. As will be understood, the pressure thus developed is determined by the pump and motor characteristics. In response to the pressure thus developed, piston 46 moves upwardly, carrying push rods 26 with it, and correspondingly actuating the mechanism connected thereto. In the course of the upward movement of piston 46 within sleeve 48, the lower edge of piston 46 sequentiallv passes above the series of openings 18 formed in the side of sleeve 48.

When piston 46 exposes the particular opening I0 in registration with column I2, a part of the fluid pressure is diverted, and forces piston upwardly, the force of spring 84 being less than the normal load on push rods 26. As will be understood, dependent upon the size of openings 10, column I2 and nipple I4, this action may be caused to either retard or entirely interrupt the upward motion of piston 46. It will also be understood that the point in the movement of piston 46 at which the retardation or interruption of the movement thereof occurs, is determined in accordance with the adjustment of sleeve 48 within cylinder 42. and that the duration of the retardation or interruption is determined by the position of piston 80 within chamber I6, and by the characteristics of spring 84. Both of these determining-factors are adjustable, as above described, by members 6I and 86.

The original rate of movement of piston 46 is resumed when piston 80 reaches its upper limit of travel. As will be understood, the upward movement of piston 46 may be limited either by the character of the mechanism towhich push rods 28 are connected, or by limit stop mechanism positioned within the ram. As illustrated in Fig. 2, members I I2 engage the upper surface of sleeve 48 and interrupt further movement of piston 46 upon its approach to the upper limit of its stroke.

When piston 46 reaches the upper limit of its travel, pump 84 continues to operate without causing further movement of any of the moving parts, motor 86 and pump 84 being preferably designed in any well known manner to operate under these conditions.

In the illustrated embodiment of the present invention, the return of piston 46 to the normal position is effected by gravity, upon interrupting the operation of pump 84 and motor 86. During this return movement, as will be understood, the fluid circulates from the region beneath piston 46 through pump 84, sleeve I04 and into the upper portion of sleeve 48. Spring 84 forces piston 80 downwardly somewhat rapidly to the normal position thereof in eng'agement with plate 88. During this movement, the fluid in the lower part of chamber I6 is forced back into sleeve 48 through column I2 and fluid passes through pipe I8 from sleeve 48 into the upper portion of chamber I6.

The modification illustrated in Fig. 5 embodies the same operating characteristics as described in connection with Figs. 1 through 4. and with the exception of the inner sleeve and relief column construction, may embody identical parts. Identical parts, accordingly, are given the same reference characters in Figs. 5, 6 and 7 as in Figs. 1 through 4.

Referring particularly to Figs. 5, 6 and 7, inner sleeve I20 is provided with an angular slot I22 cut into the side Wall thereof. A cooperating column I 24 of substantially rectangular crosssection is formed at the side of cylinder 42, and a follower I25 having one portion I26 slidably fitted within column I24 and a second portion I20 slidably fitted within slot I22, is cored out to provide a port I30 and permits passage of fluid between the interior of sleeve I20 and the interior of column I24. Rotation of sleeve I20 within cylinder 42 in response to rotation of screw 61, as previously described, causes slot I22 to move with respect to portion I28, raising or lowering the latter in column I24.

As will be understood, when piston 46 exposes the portion of slot I22 which is in communication with relief column I24, the fluid pressure is di verted through the latter, resulting in the above described interruption or hesitation in the movement of piston 46. In all other respects, the operation of the modification illustrated in Figs. 5,

6 and 7 is as previously described.

In accordance with the modification illustrated in Figs. 8 and 9, the previously described inner sleeve may be dispensed with and communication between the cylinder and the release column effected through a series of selectively adjustable valves. In Figs. 8 and 9, communication is provided between the interior of cylinder 42 and release column I40 through a series of ports I42 which extend through the side wall of cylinder 42 at rather closely spaced points. A series of needle valves I44, provided with lock nuts I46, respectively, are threaded through the outer wall of column I40 and may be selectively turned to open or close the associated ports I42. As will be understood, the staggered relationship of valves I44 permits a rather close adjustment of the point at which the hesitation of piston 46 is effected. In accordance with this modification also, depending upon the size of ports I42, and the degree to which such ports are opened, the movement of piston 46 may either be retarded or entirely interrupted, as described in connection with the other embodiment. Similarly, by appropriately opening several of the valves I44, a progressive decrease in the speed of piston 46 may be effected.

A corresponding series of valves I48 is provided to selectively control a series of by-pass ports I50 which lead from the interior of cylinder 42 to a column I52. Column IE2 is connected to the interior of cylinder 42 by a by-pass pipe I54. With this arrangement, and depending upon the particular valve or valves I48 which occupy the open position, a by-pass line around piston 46 is completed as the latter approaches the upper end of cylinder 42. The by-pass thus provided at an adjustable point in the final movements of piston 46, relieves the actuating pressure thereon and consequently interrupts the upward movement thereof.

In all other respects, the modification illustrated in Figs. 8 and 9 may be as described in connection with Figs. 1 to 4, and a more detailed description thereof, as well as the operation, is considered unnecessary.

The modification shown in Figs. 10 and 11, which includes the positive holding mechanism, as above described in a general way, may embody ram mechanism in all respects as described in connection with Figs. 1 through 9. In addition, two crank arms I10 and I12 are pivotally supported by pins I14 and I16 in stationary standards I18 and I80 respectively. The outer end of each of the arms I10 and I12 normally occupies a position adjacent the apron portion I82 which forms a part of the guard 20.

The other ends of cranks I10 and I12 are pivotally secured to trunnions I84 and I86, which are formed at opposite ends of a cross bar I88. Bar I88 is pivotally connected at substantially ii: mid oint to an arm I90 by a pin I92. Arm I9? extends into a collar I84 formed at the upper surface of the auxiliary cylinder 16. The lower part of arm I90 is cored out to receive the up wardly extending shank I96 of plunger I98. A spring 200 is seated between the end of arm I90 and a shoulder formed on plunger I98. Plunger I98 extends into the interior of auxiliary cylinder 16, in the path of the auxiliary piston 80. A key I99 on plunger I98 rides in a blind slot 20I formed in arm I90, and prevents plunger I98 from falling out of the latter.'

' In operation, the upward movement of push rods 26 associated with the main ram 28, swings the main crank arm 22 in a clockwise direction as viewed in Fig. 11, effecting an extending movement of the guard 20. At an adjustably variable pointin the path of travel of guard 20, as described in detail with reference to Figs. 1 through 9, the by-pass line 14 is opened and a portion of the actuating fluid is diverted into auxiliary cylinder 16, causing piston 80 to rise therein. This action, as previously described,

effects either a reduction in the rate of travel of guard 20 or completely interrupts the movement thereof, until auxiliary piston 80 reaches the upper limit of its stroke. At this time the original rate of movement of guard 20 is continued.

Shortly in advance of the arrival of auxiliary piston 80 at its limiting position, the upper surface thereof engages plunger I98, forcing it upwardly within arm I 90 against the force of the spring 200. The force thus transmitted through spring 200 tends to move cross arm I88 vertically as viewed in Fig. 10 and to correspondingly rotate cranks I10 and I12 in a counterclockwise direction as viewed in Fig. 11. An initial such movement, however, brings the outer ends of cranks I10 and I12 into engagement with the inner surface of apron I82. At the conclusion of the extending movement of guard 20, the lower end of apron I82 passes from the outer ends of cranks I10 and I12, releasing these members, which accordingly rotate in a counter clockwise direction, as viewed in Fig. 11 to a position beneath the end of apron I82, and thus effectively block any downward movement thereof.

It will be noted that due to the relative positioning between the ends of the cranks I10 and I12 when in looking position, and the pivot points therefor, any downward force exerted thereon by guard 20 tends to cause further counterclockwise rotation of the crank arms. With this relationship, accordingly, the cross arm I88 and connected parts are required to supply only the force required to swing the crank arms to locking position, and when in that position, they are supported against the stationary parts, illustrated as comprising the downwardly extending member 202 associated with the receptacle within which the barrier is positioned. It will also be noted that the locking mechanism comprising the crank arms is not rendered effective until the barrier reaches a final position so that, if necessary, a temporary retracting movement of the guard, against the force of main actuating mechanism, is possible during the intermediate movements thereof.

A retracting or return movement of the bar rier is efiected'as described in connection with Figs. 1 through 9, by interrupting the pumping or other actuating mechanism, in response to which action the auxiliary piston 80 begins a return movement under the influence of its biasing spring 84, thus releasing the plunger I98 and permitting cross bar I88 to return to the illustrated position by gravity. This return movement swings cranks I10 and I12 in a clockwise direction as viewed in Fig. 11, out of the path of guard 20, at which time the latter returns to the illustrated full line position by gravity. At the beginning of the return movement of cranks I10 and I12, the apron I82 may be 'the weight of the barrier, as by counter-weighting the latter, however, the arms may be caused to effectively release themselves from the apron.

Although the hydraulic ram mechanism of the present invention has been specifically described in connection with the control of a crossing guard, it will be evident that it may be applied to many other uses. It will also be evident that various modifications may be made in the form, number and arrangement of the operating parts of the guard, as well as of the hydraulic ram, within the spirit and scope of the present invention as defined in the appended claims.

What is claimed is:

1. In combination, a movable member, means for supporting said member for movement between a retracted and an extended position, actuating mechanism for said member including a fluid pressure operated ram having a cylinder, a piston supported within said cylinder, means for subjecting said piston to fluid pressure to cause movement thereof within said cylinder, means for interrupting said movement at a predetermined point to thereby interrupt said member movement and for thereafter effecting a resumption of said movement comprising an auxiliary chamber, a piston supported within said chamber, means rendered effective by movement of said first mentioned piston for diverting a portion of said fluid pressure to cause movement of said auxiliary piston, and locking means rendered effective by movement of said auxiliary piston when the latter approaches the end of its stroke for positively holding said memher in said extended position.

2. In a liquid pressure operated ram, the combination of a cylinder, a piston movably supported within said cylinder, means including a pump for transferring liquid from the cylinder space at one side of said piston to the cylinder space at the other side of said piston so as to cause movement of said piston in a predetermined direction in the cylinder, an auxiliary chamber, an auxiliary piston movably supported in said auxiliary chamber, means acting against one side of said auxiliary piston for biasing said auxiliary piston to a predetermined-position in said auxiliary, chamber, a liquid connection between said first-mentioned means and said auxiliary chamber for applying fluid pressure to the opposite side of said auxiliary piston, a liquid connection between the part of said auxiliary chamber at said one side of said auxiliary piston and that cylinder space from which the pump draws liquid, and valve means comprising a ported sleeve rotatably interposed between said piston and said cylinder for controlling said first mentioned liquid connection in accordance with the position of said piston.

3. In a liquid pressure operated ram, the combination of a cylinder, a piston movably supported within said cylinder, means including a pump for transferring liquid from the cylinder space at one side of said piston to the cylinder space at the other side of said piston so as to cause movement of said piston in a predetermined direction in the cylinder, an auxiliary chamber, an auxiliary pistonmovably supported in said auxiliary chamber, means acting against one side of said auxiliary piston for biasing said auxiliary piston to a predetermined position in said auxiliary chamber, a liquid connection between said first-mentioned means and said auxiliary chamber for applying liquid pressure to the opposite side of said auxiliary piston, a liquid connection between the part of said auxiliary chamber at said one side of said auxiliary piston and that cylinder space from which the pump draws liquid, and valve means for controlling said first mentioned liquid connection comprising a sleeve rotatably interposed between the piston and the cylinder and having a plurality of peripherally and longitudinally spaced ports therein disposed to be exposed by the piston as the latter moves in the cylinder, the cylinder having a port in communication with the first mentioned liquid connection disposed to register with said sleeve ports as determined by the rotative position of the sleeve.

4. In a fluid pressure operated ram, the combination of a cylinder, a piston movably supported within said cylinder, means including a pump for applying fluid pressure to the piston to cause movement thereof within the cylinder, and means for retarding the speed of movement of the piston for a predetermined interval when the piston reaches an intermediate point in its travel, comprising an auxiliary chamber, an auxiliary piston in said auxiliary chamber and having-means associated therewith for urging it in one direction therein, a fluid connection for transferring fluid from said cylinder to said auxiliary chamber so as to urge said auxiliary piston in the opposite direction, and valve means for controlling said fluid connection comprising a valve rotatably interposed between the cylinder and piston having a plurality of peripherally and longitudinally spaced ports therein disposed to be exposed by movement of the piston, said cylinder having a port therein disposed to register with one of the sleeve ports in accordance with the rotative position of the valve.

JAMES MOORE EVANS.

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