US3413767A

US3413767A - Stabilizers for fluid cylinder plungers

Info

Publication number: US3413767A
Application number: US619884A
Authority: US
Inventors: Wilson John Hart
Original assignee: Wilson Manufacturing Co
Current assignee: Wilson Manufacturing Co; Oil States Industries Inc
Priority date: 1967-02-13
Filing date: 1967-02-13
Publication date: 1968-12-03
Anticipated expiration: 1985-12-03

Description

J. H. WILSON Dec. 3, 1968 STABILIZEHS FOR FLUID CYLINDER PLUNGERS 7 Sheets-Sheet 1 Filed Feb. 13, 1967 Dec. 3, 1968 J. H. WILSON 3,413,767

STABILIZERS FOR FLUID CYLINDER PLUNGEHS Filed Feb. 13, 1967 7 Sheets-Sheet 2 7 Sheets-Sheet I JOHN HART WILSON INVENTOR Ea HIS AGENT 4 w m w J. H. WILSON Dec. 3, 1968 STABILIZERS FOR FLUID CYLINDER PLUNGERS Fil'ed Feb. 13, 1967 Dec. 3, 1968 J. H. WILSON STABILIZERS FOR FLUID CYLINDER PLUNGERS 7 Sheets-Sheet 4 Filed Feb. 13, 1967 5 f a I m M m H a 2 O 9 "w 2 L c QW\\\\\\\ V Y\\\\\ \&\\\\ ,\\\\\\\\\\\\\\Nk- JOHN HART WILSON INVENTOR.

MAG E N T Dec. 3, 1968 J. H. WILSON 3,413,767

STABILIZERS FOR FLUID CYLINDER PLUNGERS Filed Feb. 13, 1967 7 Sheet-Sheet b 32 523 i w i Q 50 J S w Q JOHN HART WILSON IN VEN TOR.

Dec. 3, 1968 .1. H. WILSON 3,413,767

STABILIZERS FOR FLUID CYLINDER PLUNGERS Filed Feb. 1:5, 196? 7 Sheets-Sheet 6 JOHN HART WILSON IN VEN TOR.

HIS AGENT Dec. 3, 1968 J. H. WILSON 3,413,767

STABILIZERS FOR FLUID CYLINDER PLUNGERS Filed Feb. 13, 1967 7 Sheets-Sheet '7 JOHN HART WILSON IN VEN TOR.

3,413,767 STABILIZERS FOR FLUID CYLINDER PLUNGERS John Hart Wilson, %Wilson Mfg. Co., P.0. Box 1031, Wichita Falls, Tex. 76307 Continuation-impart of application Ser. No. 410,700,

Nov. 12, 1964. This application Feb. 13, 1967, Ser.

6 Claims. (Cl. 52115) ABSTRACT OF THE DISCLOSURE A stabilizer for stabilizing plungers of fluid cylinders of high slenderness ratio, to support the plunger against lateral deflection within the length thereof, when the plunger is used in towers, such as extensible masts, or in elavator shafts. The stabilizing device utilizes arms to sequentially move into engagement, at spaced intervals, with the plunger as the extensible mast or the elevator car moves upward, and to move out of engagement with the plunger and out of the path of the extensive mast or elevator car as the extensible mast or elevator car moves downward. The stabilizer arms are maintained in disengaged position while the extensible mast or the elevator car is moved therebelow.

This application is a continuation-in-part and co-pending with application Ser. No. 410,700, filed Nov. 12, 1964, and now abandoned for Stabilizer for Fluid Cylinder Plungers Such as Used in Connection With Masts and Extensible Towers.

This invention relates to improvements in a stabilizer for fluid cylinder plungers such as used in connection with masts, extensible towers and other fluid cylinder plungers which may be extended to such length that are not stable against lateral movement.

Various stabilizers have been proposed heretofore such as disclosed in my Patent No. 3,016,992 granted Jan. 16, 1962, for Stabilizer for Fluid Cylinder Plungers of High slenderness Ratio.

The present fluid cylinder plunger stabilizer is so constructed that a minimum of mechanism is required to operate the stabilizer, which is operated automatically as the extensible inner portion of the mast or tower is moved upward or downward past a predetermined point, or the plunger is extended to an unstable height. While only one stabilizer is shown, as many as desired may be made to operate within the length of the outer mast structure or tower and stabilizer arms will move into place to stabilize the plunger of a cylinder as the inner mast portion moves upward, and the stabilizer arms will move out of stabilizing position as the inner portion of the mast or tower is lowered.

By having a mast or tower that is constructed with the inner mast portion thereof movable with respect to the outer mast structure and with the inner portion being lifted by a hydraulic ram, the present device will stabilize the plunger each time the lower end of the inner mast portion passes a section of the outer mast structure, where a stabilizer is mounted. In this manner a relatively slender plunger that is of extreme length may be readily used where heretofore the extension of such plunger was limited, if it was unstabil ized. Stabilizers may be so constructed as to stabilize a plurality of plungers arranged to operate in parallel relation, and for stabilizing extended plungers such as plungers for elevators using fluid cylinders.

An object of this invention is to provide a plunger stabilizer which will prevent an elongated plunger from moving laterally as it extends outward from a hydraulic ram such as is used for mast and tower sections and the like.

nited States Patent Still another object of the invention is to provide a plunger stabilizing mechanism that will move into place and surround the plunger of a hydraulic cylinder, which is of high slenderness ratio, at spaced intervals along the length thereof as the plunger becomes exposed, so as to prevent lateral deflection of the exposed, extended plunger.

Still another object of the invention is to provide a hydraulic plunger gripping mechanism to grip and sta bilize a plunger, which mechanism is simple in construction, easy to apply to a mast or a tower, and which operates automatically, and which requires a minimum of attention and service.

Yet another object of the invention is to provide a plunger with stabilizing arms for stabilizing plungers of high slenderness ratio, which stabilizer arms will move into place as the plunger of a hydraulic cylinder moved upward within a structure, to support the plunger against lateral deflection, at spaced intervals along the length thereof.

A further object of the invention is to provide a plunger stabilizing mechanism to stabilize the plungers of fluid cylinders, as the plungers are extended, to maintain the plungers substantially in alignment with the fluid cylinders, with the stabilizers being moved into engaged relation with respect to the plunger sequentially, as the plunger moves outward with respect to the fluid cylinder, so as to support the plunger against lateral deflection.

Yet a further object of the invention is to provide a plunger stabilizer for stabilizing plungers of high slenderness ratio, such as used in hydraulic elevators in the elevator shafts of buildings, and the like, whereby the plunger stabilizers will be sequentially moved into supporting relation with the plunger as the elevator car moves upward within the elevator shaft, and which stabilizers will be sequentially moved into retracted position as the elevator car moves downward.

In the manufacture of portable masts or tower structures, it is desirable to telescope the upper portion of the mast or tower into the lower portion thereof, so that the structure will be within acceptable limits for movement over the highways, but which may be raised to an upright position and extended into operating position to present a mast or derrick of suflicient height to enable the handling of long lengths of drill stem or pipe, so as to expedite the drilling an/or servicing of deep wells, such as oil wells or the like.

The present device is suitable for use on hydraulic cylinder plungers, such as used in hydraulic elevators of buildings \and the like. The present plunger stabilizers enable plungers of high slenderness ratio to be used in multi-story buildings, the height of which, heretofore, made it impossible to stabilize plungers against lateral deflection, therefore, the use of hydraulic elevators, so far as known, has been confined to buildings of two to six stories, however, the use of the present device enables plungers to be used in buildings of twelve or more stories, whereby the plungers will be maintained against lateral deflection by the arms of the stabilizer.

Embodiments of the invention are illustrated in the accompanying drawings, in which like reference characters designate like parts in the several views thereof, in which:

FIG. 1 is a tl'lOI'lZOIItfll, transverse, sectional view taken through the mast structure, showing the arms of the stabilizer surrounding and supporting the plunger, with the section being taken on the line 1-1 of FIG. 2, looking in the direction indicated by the arrows;

FIG. 2 is a fragmentary front elevational view of an outer and inner section of a mast, showing the plunger stabilizer members surrounding and, being in gripping relation with a hydraulic cylinder plunger;

FIG. 3 is a fragmentary side view of the mast structure as shown in FIG. 2, but with the plunger stabilizer shown in vertical, disengaged position;

FIG. 4 is a view on reduced scale of a fragmentary portion of the inner portion of a mast, showing the plunger stabilizer in vertical, disengaged position;

FIG. 5 is a view showing a plunger stabilizer arm apart from the mast;

FIG. 6 is a longitudinal, sectional view taken through the shaft of an elevator, with parts broken away and shortened, showing an elevator car, a hydraulic cylinder plunger assembly associated therewith, and showing hydraulic cylinder plunger stabilizer arms in elevation within the elevator shaft;

FIG. 7 is a fragmentary, longitudinal view, on an enlarged scale, with portions broken away, with portions shortened, and with portions shown in elevation, with the plunger of the hydraulic cylinder stabilizer arms being shown in retracted position;

FIG. 8 is a view similar to FIG. 7, but showing hydraulic cylinder plunger stabilizer arms in outwardly extended position, and as being interengaged with the plunger of the hydraulic cylinder;

FIG. 9 is a sectional view taken on the line 9-9 of FIG. 8, looking in the direction indicated by the arrows;

FIG. 10 is a further enlarged, fragmentary, perspective view of one of the hydraulic cylinder plunger stabilizer arms, shown apart from the elevator shaft, with parts broken away, with parts shown in section and parts shortened to bring out the details of construction;

FIG. 11 is a fragmentary side elevational view, on a scale similar to FIG. 10, with portions broken away, with portions shortened, and with portions shown in dashed outline, of the latch mechanism for holding the arms, including the arm, shown as holding the arm in retracted position;

FIG. 12 is a view similar to FIG. 11, but showing one of the arms for stabilizing the hydraulic cylinder plunger in an outwardly extended position; and

FIG. 13 is a fragmentary, perspective view, shown apart from the elevator car and elevator shaft, of the latch mechanism for holding a plunger stabilizer arm in retracted position and for releasing the arm.

With more detailed reference to the drawings, the numeral 1 designates generally the outer mast structure which slidably receives an inner mast portion 2 therein. The inner mast portion has a hydraulic cylinder plunger 4 extending from the hydraulic cylinder (not shown) downward to the base of the mast when the mast or tower is in upright position.

In the extending of relatively tall masts or towers by a hydraulic ram, as by sliding one section within another section, it is necessary to stabilize the plunger thereof to prevent the lateral movement of the plunger with respect to the normal axis thereof.

In the present invention the inner portion 2 of the mast or tower is longitudinally movable with respect to the outer mast structure 1 and the plunger 4 is positioned mediate the sides of the outer mast structure, and is capable of being stabilized by a pair of arms or stabilizing frames 6, each of which arms or frames is mounted on a shaft 8, which shafts are each journaled in bearings 10 on the opposite sides of the outer mast structure. Each arm 6 is secure to the respective shafts 8 and rotatable therewith through an arc of approximately 90 degrees. The shaft 8 has an outwardly extending lever 12 mounted thereon and secured thereto, each which lever is apertured and to which is secured an end of a tension spring or spring means 14 with the other end thereof being anchored to an apertured lug 16 on the respective outer mast structure. Levers 12 are adapted to move through an arc of 90 degrees from a position as shown in full outline in FIG. 2 to the position as shown in dashed outline in FIG. 2.

Each of the arms 6 has a pair of upstanding lugs 18 thereon, which lugs are apertured to receive an axle of a roller 20 therein to mount the roller 20 in journaled relation thereon.

Upon raising the mast, as the mast moves upward the rollers 20 roll off of trackway 24 on to a cam 22, which is arcuate and which will permit the arm 6 to move from the position as indicated in dashed outline in FIG. 2 to the position indicated in full outline in FIG. 2, upon action of spring 14 to act upon lever 12 to rotate shaft 8 through an arcuate movement of approximately 90 degrees.

The inner end portion of each arm 6 has an arcuate semi-cylindrical portion 7 secured thereon, which is preferably lined with padding material, such as woven belting, as indicated at 7a, so that the semicylindrical portion 7 will blindly engage around the plunger 4 to hold the plunger against lateral movement. As the inner mast portion 2 moves upward successive pairs of arms 6 will swing outward so semi-cylindrical portions 7 will surround the plunger at spaced intervals to stabilize the plunger against lateral movement in any direction.

Normally the arms extend outward in horizontal position as indicated in FIGS. 2 and 3 under the influence of spring 14 when not constrained to another position by a cam 22 and trackway 24. When the inner mast portion 2 is telescoped into outer mast structure 1, the cam face 22. which is arcuate, engages the roller 20 as indicated in FIG. 2 and as the inner mast portion 2 moves downward each of the cam faces 22 contact the respective rollers 20 to move the arms 6 from the position shown in full outline in FIGS. 2 to the positions shown in dashed outline in FIG. 2. As the inner mast portion moves downward the trackway 24 engages the rollers 20 and holds the arms 6 in position as indicated in dashed outline in FIG. 2. As the inner mast 2 moves by successive arm mountings 6. each pair of arms is acted upon in a similar manner until the mast is in full telescoped position.

Modified form of invention Various hydraulically operated elevators have been proposed heretofore, but due to the deflection of the plunger of a hydraulic cylinder, it has been impractical to use such elevators, insofar as known, in buildings in excess of six stories in height. The present stabilizer for the plungers of elevators is so constructed, that such elevators may be operated in buildings of twelve or more stories in height, with hydraulic cylinder utilizing a plunger of relatively small diameter, the use of which would be unacceptable, if the plunger was not stabilized against lateral deflection.

FIGS. 6 through 13 disclose a modified form of the invention, wherein buildings, such as the building designated generally at 31, has an elevator shaft 32 therein, with an elevator car 34, which car has guide shoes 36 thereon for operation in guided relation on guide rails 38, within elevator shaft 32, by hydraulic cylinder 40 and the plunger 42 thereof, so the plunger will lift the car 34 to the desired height or to the desired floor, such as indicated at 44.

The hydraulic cylinder 40 has a conduit 46 connected thereto and to a hydraulic fluid supply unit 48, such units being well known in the art of hydraulic elevators. The specific controls of the elevator, such as floor level controls, either automatic or manual, are not shown, as the present hydraulic cylinder plunger stabilizer is usable with all forms of controls, as the present device is selfactuating, both as the elevator car moves upward within shaft 32 or as the car moves downward therein.

The guide rails 38 are supported in the customary manner within elevator shaft 32, either by being bolted directly to the masonary wall 50 or to structural members. such as transverse beams 52 which are mounted on upright structural beams 54. The stabilizing mechanism, for this form of the invention, includes stabilizer arms, which are designated generally at 56, and the latch mechanism, designated generally at 58, which are mounted on structural members, such as the upright beams 54, at spaced intervals throughout the length of the elevator shaft 32, so as to support the plunger 42 of the hydraulic cylinder 40, against lateral deflection, as the car moves upward in guided relation on guide rails 38, within the elevator shaft 32. The safe working limit of a plunger of high slendemess ratio is that at which the plunger would not deflect laterally, therefore, the greatest extended length of the present plunger, between the lateral supports, will be within the safe working limits, therefore, as the elevator car moves upward, the arms 56, which are pivotally mounted on apertured support members 60 pivotally move from the position shown in the upper portion of FIG. 6 to the position shown in the lower portion of FIG. 6.

Each of the arms 56 is composed of a pair of outwardly extending, apertured members, which member are pivotally mounted on the respective shafts 61, on opposite sides of the elevator shaft 32. Each shaft 61 extends through the apertures of the respective pairs of arms 56 and through the respective apertured support members 60. A transverse brace member extends between the members of the respective arms 56, and is secured thereto, which braces each support a pair of apertured lugs 64, on the upper side of each arm 56, FIG. 10. A shaft 66 on each of the arms passes through the apertured lugs 64 and through the respective rollers 68, each of which rollers is in aligned relation with the respective trackways 70 on opposite sides of the car 34, which permits the rollers to roll along the trackways as the car moves upward and as the car moves downward. Each trackway 70 has a curved lower end 72 to permit the rollers 68 to move off the lower end of car 34, as the car moves upward.

The roller 73 of the respective latch mechanisms 58, as shown in full outline in FIG. 11, will be engaged by the respective pivoted, apertured dogs 74, as shown in FIG. 11, each of which dogs are pivotally mounted on the respective shafts 76. The shafts 76 are each mounted on pairs of apertured lugs 78, which lugs are secured on each side of the car 34. As the car moves upward, the upper end of each dog 74 moves, which engages the rollers 73 to move the respective arms of latch mechanisms 58 about the axis of shaft 80, which shaft passes therethrough and through apertured lugs 82, which are mounted on upright beams 54.

The latch mechanisms 58 are moved against tension of springs 84, which springs are biased between one of the latch mechanisms 58 and one of the apertured support members 60 on each side of the car 34, until the latch mechanism 58 is in the position shown in dashed outline in FIG. 11, whereupon, the tapered wedge face 86 of the latch mechanism 58 will be moved upward to disengage wedge face 88 of outwardly extending lever 89. As the rollers 68 move from the longitudinal trackways 70 onto the curved portion 72 thereof, the respective springs 90, each of which is attached to a lever 92 on each arm 56 and to an outwardly extending lug 93 on each of the upright beams 54, which will cause each arm to rotate about the axis of the respective shafts 61, from the position as shown in full outline in the upper portion of FIG. 6, to the outwardly extended position as shown in the lower portion of FIG. 6 and in FIGS. 8, 9, 10 and 12.

An arcuate yoke 94 is mounted on the end of each arm 56 remote from the pivot shaft 61, and the arcuate curvature of each yoke 94 is complementary to the outer diameter of the plunger 42, which plunger is engaged by the yokes 94. The curved portion of each yoke 94 is preferably lined with an arcuate lining 96. which lining may be leather, rubber, plastic composition, or metal, which will not mar the surface of the plunger 42. It is to be pointed out that the upper end of each arcuate yoke 94 lies in a horizontal plane which is coextensive with the axis of the respective horizontal shafts 61, or slightly lower, because, as the arms move downward, the upper edge of the lining 96 and arcuate yoke 94 must move arcuately away from the plunger 42, if the arcuate yokes 94 and the linings 96 are to fit in snug relation around the plunger 42. After the elevator car 34 is moved upward, the arms 56, which in the present instance, are shown to be on opposed lateral sides of the elevator shaft, the plunger 42 will be supported against lateral deflection, and with these arms being at spaced intervals throughout the length of the plunger 42, the plunger will be maintained in true axial alignment with the axis of the hydraulic cylinder 40 and with the anchor point on the lower side of the car 34.

The present elevator car 34 shows the guide shoes 36 and the guide rails 38 located medially between the front and back of the car, and the arms 56 and the plunger 42 located forwardly thereof. However, this :is merely representative, as the cylinder can be located centrally of the car and the guide shoes 36 and guide rails 38 off-set laterally with respect thereto, or, the arms can operate on the front and back of the elevator shaft, or, the arms may be disposed on each side of the elevator shaft, with the guide rails 38 and guide shoes 36 being located near or at two diagonal corners of the elevator car, if more angular divergence is desired between the members of the arms 56.

With the plunger 42 stabilized in the manner set out above, a hydraulic elevator may be used for buildings of twelve or more stories, and a plunger of smaller diameter than is customarily used in buildings of lesser height may be used, depending on the load to be carried and the speed at which it is desired to have the car operate.

The latch mechanisms 58 are each located out of alignment, longitudinally, with the respective trackways 70, and the dogs 74, as will best be seen in FIG. 9, and are in longitudinal alignment for engagement with the respective rollers 73 on each side of the car 34, as the car moves upward. The upper ends of the trackways are curved inwardly, as indicated at 71-71, so as to guide the respective rollers 68 onto the respective trackways 70 with the respective rollers 73 of the latch mechanisms 58 engaging dogs 74, as the car moves upward, whereupon, as the car passes beyond a certain point, the latch mechanisms will move :arcuately about the respective shafts until the rollers 73 and dogs 74 will be disengaged, whereupon, the latch mechanisms 58 will move into the position as shown in full outline in FIG 12, with a leg 59, secured to the bottom of each latch mechanism 58, the leg will come to rest on the respective plates 63, which are secured to one of the support members 60 on each side of the elevator shaft, as will best be seen in FIGS. 10, 11 and 12, and the springs 84 will hold the latch machanisms 58 in outwardly extended positions ready to engage the wedge face 88 of each lever 89, when the car 34 moves downward, as will be more fully described hereinafter.

When the car 34 has reached the upper-most point of the travel thereof, and it is desired to reverse the travel, the hydraulic fluid is exhausted from the cylinder 40 in a conventional manner, to allow the car to move downward. As the car moves downward, the lower angulated face of the dog 74, on each side of the car 34, will move into contact with the periphery of the respective rollers 73, which will cause the respective dogs 74 to move inward against the tension of the respective torsion springs 75, which springs are biased between each of the dogs 74 and one of the lugs 78, with the dogs 74 yielding inwardly, as indicated in FIG. 7, and since the rollers 68 have engaged the curved portion 72 on the lower side of car 34, the rollers 68 will move onto the trackways 70, which are parallel to the line of travel. As this movement takes place, the angulated face of each lever 89 will engage the respective angulated faces 87 on the lower side of each of the latch mechanisms 58, and upon the arms swinging through an are from the position shown in FIG. 8 to the position shown in FIG. 7, the levers 89 will move latch mechanisms 58 upward about shafts 80 until the wedge face 88 will wedgingly engage with wedge face 86 on each latch mechanism 58, with the springs 84 holding the latch mechanisms in the position shown in full outline in FIGS. 7 and 11, the car 34 will move downward to cause the dogs 74 to engage successive pairs of rollers 73 on the latch mechanisms 58, which dogs will yieldingly pass the rollers 73 of the latch mechanisms 58, with the springs 84 maintaining the latch mechanisms 58 engaged with the levers 89. Each time the dogs 74 disengage rollers 73, as the car moves downward, the dogs 74 will be returned to the position shown in FIGS. 11 and 13, and the face 98 thereon will seat against an abutment, such as the face of the car, to maintain the dogs 74 at an angle, as shown in FIGS. 11 and 13, so the dogs will engage the rollers 73 upon upward movement of the car 34, which dogs will yield as the car 34 passes downward thereby.

As the car 34 moves downward, the rollers 68 move ofi the arcuate upper end of each trackway 70, as shown in the upper portion of FIG. 6, and upon the car 34 returning to the lowermost point of travel, all the arms are held in retracted position, substantially as shown in the upper portion of FIG. 6, and in FIG. 7.

Having thus clearly shown and described the invention, what is claimed as new and desired to be secured by Letters Patent, is:

1. A stabilizer for fluid cylinder plunger in combination;

(a) an outer stationary structure,

(b) an inner movable portion arranged for sliding movement within said outer stationary structure,

() a hydraulic cylinder mounted in fixed relation with respect to said outer stationary structure,

(d) an elongated hydraulic cylinder plunger operatively fitted within said hydraulic cylinder for move ment relative thereto and interconnecting the outer stationary structure and the inner movable portion,

(e) a pair of complementary, movable arms pivotally mounted on horizontal axes on said outer stationary structure and adapted to extend laterally thereinto to engage said hydraulic cylinder plunger, when in one position, and to move out of engagement with said hydraulic cylinder plunger when in another position.

(f) arm actuating means, which are springs biased between the respective arms and the outer stationary structure, associated with said outer stationary structure to urge said pair of complementary arms into engagement with said hydraulic cylinder plunger upon movement of said inner movable portion thereabove in said outer stationary structure,

(g) said inner movable portion has a pair of trackways thereon, which are in aligned relation with the longitudinal movement of said inner movable portion,

(h) each said trackway having a curved portion near the lower end of said inner movable portion, each which curved portion forms a cam,

(i) a cam engaging member mounted on a side of each said arm and being engageable with said cams and said trackways on said inner movable portion, when said inner movable portion is moved downwardly to move said arms out of engagement with said plunger and out of the path of said inner movable portion, and being adapted to disengage said trackways and said cams on said inner movable portion, when said inner movable portion is moved upwardly, so said arms will extend laterally inward to engage said plunger.

2. A stabilizer for a hydraulic cylinder plunger, as

defined in claim 1; wherein (a) said cam engaging member, mounted on a side of each arm, is roller means.

3. A stabilizer for a hydraulic cylinder plunger, .15

defined in claim 1; wherein (a) said arm actuating means includes an outwardly extending lever secured to each arm and being coordinated to move therewith, and

(b) said springs, which are biased between the respective arms and the outer stationary structure, have one end of each spring connected to each said lever.

4. A stabilizer for a fluid cylinder plunger for an elevator or the like, which stabilizer comprises in combination:

(a) an outer stationary structure,

(1) said outer stationary structure having an eievator shaft formed therein for a portion of the height thereof,

(b) an elevator car movably mounted within the elevator shaft for guided movement longitudinally therein,

(c) a hydraulic cylinder mounted in fixed relation with respect to said outer stationary structure,

(d) an elongated plunger operatively fitted within said hydraulic cylinder for movement relative thereto, and having the end of said plunger remote from said cylinder connected to said elevator car,

(e) horizontal shafts mounted on said outer stationary structure,

(f) a pair of complementary, movable arms, one mounted on each said horizontal shaft for rotation about the respective axes thereof to complementally engage said hydraulic cylinder plunger when in one position, and to move said arms out of engagement with said plunger, when in another position,

(g) arm actuating means, which are springs biased between the respective arms and the outer stationary structure, which urge said pair of complementary arms into engagement with said plunger upon movement of said elevator car upward in said elevator shaft,

(h) said elevator car has a pair of trackways thereon which are in aligned relation to the longitudinal movement of said car,

(i) each said trackway having a curved portion near the lower end of said car, each which curved portion forms a cam,

(j) a cam engaging member mounted on a side of each said arm and being engageable with said cams and said trackways on said car, when said elevator car is moved downwardly to move said arms out of engagement with said plunger and out of the path or said elevator car, and being adapted to disengage said trackways and said cams on said car, when said car is moved upwardly, so said arms will extend laterally inward to engage said plunger.

5. A stabilizer for a fluid cylinder, as defined in claim 4; wherein (a) a latch means is pivotally mounted on said outer structure,

(b) dog means pivotally mounted on said elevator car.

(1) said latch means being in longitudinal alignment with the path of said pivoted dog means upon movement of said elevator car,

(2) said dog means being adapted to engage said latch means to move said latch means out of locking engagement with said arms to permit said arms to swing laterally inward into engagement with said plunger upon upward movement of said elevator car, and

(3) said pivoted dog means adapted to yield upon engagement with said latch means upon downward movement of said car to permit said arms to be maintained in locked relation out of the path of said elevator car as said elevator car moves downward.

6. A stabilizer for a fluid cylinder, as defined in claim 5; wherein (a) each said arm has a lever thereon,

9 10 (1) each said lever having a Wedge-like face tracted position out of the path of said elevator thereon, car. (2) each said latch mechanisms having a comple- References Cited mentary Wedge-like face to engage the Wedge- UNITED STATES PATENTS like face of each sa1d lever, when 1n one position 5 and to release said wedge'like faces when said 773,478 10/1904 Conner et a1 187 17 latch mechanisms are in another position, and 827,282 7/1906 AT 1der5n (3) a spring biased between said latch mecha- 3,016,992 1/1962 Wllson 52115 nisms and said outer stationary structure to normally urge the Wedge-like face of said lever and 10 HENRY SUTHERLAND P'lmary Exammer' the Wedge-like face of said latch mechanism into PRICE C. FAW, Assistant Examiner. Wedging relation to maintain said arms in re-