US3134232A - Jack - Google Patents

Description

May 25, 1954 J. M. BARosKo 3,134,232

JACK

Filed 00V 2. 1961 2 sheets-sheet 1 /4/ f@ f4 j A A May 26, 1964 J. M. BARosKo JACK 2 Sheets-Sheet 2 Filed Oct. 2. 1961 INVENTOR.

United States Patent O of Delaware Filed Uct. 2, 1961, Ser. No. 142,269 11 Claims. (Cl. 60-52) This invention relates to an improvement in the hydraulic jack art, and more particularly to an improved multispeed hydraulic jack.

The present invention is directly related to hydraulic jacks in which control means are provided to cause the power applying ram to travel rapidly when approaching a load and to thereafter slow down and develop the necessary power as the load is applied. In such apparatus the change from high to low speed travel must be effected positively and automatically. Several devices have been previously proposed to accomplish the foregoing results. This invention provides new and improved apparatus for obtaining automatic and positive two-speed plunger travel; and, in addition, provides stroke controlling means which can be utilized to positively limit the length of travel of the jack ram and prevent continued application of excess power to the jack when a predetermined jack displacement has been obtained.

The primary object of the present invention is to provide means to positively control the displacement of the ram of a hydraulic jack. It is another object of this invention to provide an improved two-speed hydraulic jack in which the length of travel of the jack ram is automatically and effectively controlled. A further object is to provide jack control means to prevent continuous excess power application to the jack after a predetermined jack position has been attained. Still another object of the present invention is to provide a multispeed, hydraulically actuated, power applying device having an improved design which is automatic and reliable in operation; yet compactly and sturdily constructed to insure maximum life. Other objects and advantages of the invention will appear in the following detailed description in which reference is made to the accompanying drawing wherein:

FIGURE 1 is a side elevational view in section showing an illustrative embodiment of the present invention;

FIGURE 2 is a sectional view taken along the line 2 2 in FIGURE l;

FIGURE 3 is a sectional View taken along the line 3-3 in FIGURE l;

FIGURE 4 is a side elevational View, in section, of a portion of the apparatus shown in FIGURE l in another operative position; and

FIGURE 5 is a side elevational View, in section, of the apparatus shown in FIGURE 1 with all of the valving and uid passages revolved into the same plane in order to illustrate the complete operationalsequence.

Referring now to the drawings, the illustrative embodiment of the jack comprises a base member in the form of a casting and a capmember 12 which are spaced by a cylindrical outer tube 14. A cylindrical sleeve element 16 of smaller diameter than the cylinder element 14 is concentrically mounted therewithin and denes a chamber 18 therewith.v The chamber 18 provides a uid reservoir for jack actuating hydraulic lluid.y

Threaded end portions 20, 22 of the sleeve element 16 are threadably secured in threaded openings 24, 26 in the cap member and the base member, respectively. In this manner, the cap 12' and outer cylinder 14 are rigidly secured to the base member 10. A ram element Sliis slidably supported within a central bore 32 in the capY 12 and extends inwardly within the sleeve 16 and defines a chamber 34l therewith. A passage 38 in the cap conicc nects the chambers 18 and 34 for a purpose to be hereinafter described. The ram element is commonly referred to as a jack plunger or ram in the hydraulic jack art. The outer end 35 of the ram is adapted to abut and transfer power to a Work surface. The ram is provided with a central bore 36 and terminates in a reduced end portion 39. A piston forming annulus 40 is secured on the reduced end portion along with a packing 42 which divides the chamber 34 into upper and lower fluid cavities. A tube 44 is mounted Within the central bore 36 of the ram.

' The tube is threadably engaged at one end 46 within a threaded bore 48 in the base member 10 and is threadedly engaged at the other end 50 with an enlarged piston head 52. A central bore 54 in the piston head cornmunicates with the central bore 56 of the tube 44. The piston 52 is -slidably engaged with the wall of the central bore 36 and conventional sealing means 56 divide the bore 36 into upper and lower lluid cavities.

Pump means are mounted in the base 10 and comprise a piston rod 60 reciprocably mounted in a chamber 62. The inner end of the piston rod is reduced in diameter at 64 to provide a seat for packing means 66 which are secured thereon by a nut assembly 68. The other end of the piston rod is connected to drive link means 70, or the like, for actuation by any conventional power source. The chamber 62 terminates in a passage 72 which communicates with a chamber 74. The chamber 74 is connected at one end by a passage 76 to a passage 78 which communicates with the fluid reservoir 18 through a lter element 80. The passage. 76 is controlled by a ball-type valve 82 which is normally biased to a closed position by a spring element S4. The other end of the chamber 74 communicates with a chamber 86 through a ball valve 88 which is normally biased to a closed position by a spring element 90. The chamber 86 is connected by a passage 92 to the passage 56 in the tube 44. In addition, the chamber 86 is connected through a ball valve 94, normally biased to a closed position by the spring element 90, and a passage 96 to a passage 98 which communicates with a chamber 19t) at the rear of the piston 40.

A release valve 104 of conventional design is mounted in a bore 106 which communicates with'the chamber 86 by a passage 168 through a valve 110. A tube release plunger 112 is slidably mounted in a release stem 114 through which the valve can be moved away from closing engagement with the passage 108. The release valve 110 connects the passage 108 to a passage 115 which communicates with the fluid reservoir 16 as shown in FIGURE 3. An overload valve 117 controls communication from a chamber 116 and a passage 118 to the reservoir through a passage 120. The overload valve includes a ball element 122 which is biased to a normally closed position closing the passage 118 by means of a sleeve124 biased inwardly by a spring element 126. As shown in FIGURE 5, the chamber 116 communicates with the pump inlet passage 72 and with a chamber 130 through a passage 132 and spring-biased ball valve 134. The chamber communicates with the piston chamber 100 through a passage 133. The chamber 100 and the central bore 36 also are connected by a passage 135 and a chamber 136 to the reservoir through a ball valve 138 and passages 140, 141 as shown in FIGURES 2 and 3. The ball valve 13S is biased to a closed position by a closed position by a spring element 142. The reservoir 16 is connected to a ller plug 150 by a passage 152.

Stroke control means are provided to positively limit the outward movement of the ram and comprise a sleeve element 16@ which is slidably mounted on the ram and has an inwardly opening tapered groove 162. A ball valve 164 is mounted in a valve seat 166 provided in the ram and controls a passage 168 which communicates with the chamber 36. A spring clement 179 is concentrically mounted on the ram and abuts the sleeve 16h at one end and the piston annulus di? at the other end. The spring 17) normally biases the sleeve 165i forwardly to a position whereat the tapered groove 162 forces the ball valve 164 inwardly onto the seat 166 to close the passage 168. As shown in FIGURE 4, the end face 172 of the sleeve 16) is adapted to engage an abutment surface, such as the surface 174 provided in the end of the cap member 12, during outward movement of the ram. The sleeve lo@ will be moved rearwardly against the bias of the spring 17 0 to position an enlarged portion of the tapered groove 162 over the ball valve 164 and permit high pressure duid in the passage 168 to open the valve and escape into the upper end of chamber 34 through the passage 180 provided in the sleeve element. High pressure fluid escaping from the passage 18@ is returned to the reservoir 18 through the passage 3S in the end cap 12.

VIn operation with the parts in the position shown in FIGURE l, the pump di) is drawn outwardly in the pump chamber 62 and draws a quantity of hydraulic fluid from the reservoir 18 through the iilter and the passages 76, '78, past the ball valve 82 into the chamber 74, and through the passage 72. When the piston rod 6i) reaches the end of its stroke and starts to return, uid is displaced from the pump chamber through the passage 72 into the chamber 74. The ball valve 22 is reseated by the spring element 84 and the pressure of the fluid in the chamber 74 to seal the passage 76. The fluid pressure in the chamber 74- moves the ball valve 3S away from its seat to open the chamber 74 to the chamber 86. Fluid flows from the chamber 74 and the chamber S6 through the passage 92 to the interior of the sleeve S6 and outwardly through the passage 54 in the valve head 52 to ll the chamber 58 and exert a force on the ram 30. The high pressure force exerted by the lluid in the chamber b on the ram causes rapid outward movement thereof. As the ram moves outwardly, the chamber 1th@ is enlarged and creates a suction which opens the ball valve 138 to permit hydraulic fluid from the reservoir 1S to flow into the chamber 161) through the passages 14:19, 141, the chamber 136, and the passage 135. The pressure diiferential between the chamber lilll and the uid reservoir 1S is large enough so that the chamber 1d@ will remain full of fluid as the plunger moves rapidly outwardly. When the end surface 3S oi the ram encounters the load, pressure is built up in the chamber 1d@ by high pressure fluid being pumped from the chamber 62 into the chamber 116 until the ball valve 134 opens and permits the high pressure fluid to ow into the cylinder cavity lili) through passage 133. Thereafter the ram may be moved against the load by the build up of high pressure fluid within the chamber 106.

When the ram reaches a predetermined extended posil tion, as shown in FIGURE 4, the sleeve element 166i will come into abutting engagement with the abutment surface 174 and cause the sleeve to be moved rearwardly against the bias of the compression spring 170. Rearward movement of the sleeve permits the ball valve 164 to be opened by accumulated high pressure in the chamber 100 which aiso fills the chamber 36. The high pressure iiuid will be bypassed through the passage 168 in the ram and the passage 13% in the sleeve through the passage 38 into the fluid reservoir 1S. ln this manner, when the ram has reached a predetermined stroke position, as determined by the location of the abutment surface 174, any excess high pressure duid which would tend to move the ram beyond the predetermined position is bypassed through the passage 158. Accordingly, actuation of the pumping means may be continued and the pumping means may continue to pump fluid into the chambers 1% without causing any damage to the equipment; and yet, maintain a predetermined load on the ram to support the load in the extended position. When the release valve 119 is actuated through the release control 112, high pressure fluid in the chamber 1d@ will be vented through the passages 92, 9S, to chamber 36 and passage 108. The passage returns the iluid to the fluid reservoir and the ram returns to the original position whereupon the apparatus is ready for another cycle.

1t is contemplated that the abutment surface 174 can be provided at any position along the path of movement of the ram by the provision of an adjustable abutment surface which may be fixed to the inner periphery of the sleeve element 16 at any desired position. Although, the ball valve 16d and slide sleeve lei) are particularly well adapted for controlling the ram extension and provide advantageous results, it is contemplated that other alternative valve means might be utilized. It is intended that other modications and changes in the details of construction and the arrangement of the parts embodying the principles of the inventionare to be included within the scope of the invention, as dened by the appended claims, except insofar as limited by the prior art.

What is claimed is:v

1. In a two-speed hydraulic jack, a base member, a cap member, hollow piston means connected to said base member and extending therefrom, reciprocable ram means having a central bore and piston means secured to the lower end thereof, said ram means being reeiprocably supported within and extending through said cap member, said hollow piston means being slidably received within said central bore, cylinder means surrounding and slidably supporting said piston means on said ram means, a iluid reservoir, passage means connecting said fluid reservoir to said central bore and said cylinder means, pump means to iirst deliver Huid under pressure to said central bore through said hollow piston means and subsequently to deliver fluid under pressure to said cylinder means, a bypass port means interconnecting said fluid reservoir and said central bore and said cylinder means above said piston means on said ram means, and valve means controlling iiow through said port means and preventing ilow therethrough until said reciprocable ram-means reaches a predetermined extended position and thereafter bypassing excess iluid supplied to said central bore from said pumping means which tends to further extend said ram means to said reservoir, said valve means being spaced between said cap member and said piston means on said ram means and being completely separate therefrom and comprising a valve member movable substantially transversely to the path of movement of said ram means between an open position and a closed position relative to said bypass port means, and valve actuating means axially reciprocable in a path parallel to the path of movement of said ram means to move said valve member between said open position and said closed position.

2. The jack apparatus as defined in claim 1 and wherein said valve means is responsive to the position of said ram means and operable automatically when said ram means reaches a predetermined position.

3. The jack means as defined in claim 1 and wherein said valve actuating means comprises a control sleeve slidably mounted on said ram means and being movable therewith, spring means connected to said control sleeve to normally bias said control sleeve to a valve closing position, and abutment means located in the path of movement of said sleeve means with said ram means at a predetermined position whereby said sleeve means will engage said abutment means and be displaced against the bias of said spring means relative t0 said ram means to open said valve means and bypass said excess ram actuating fluid to said reservoir.

4. In a jack, cylinder means, an extendable ram means having a piston assembly reciprocably mounted in said cylinder means, a liuid reservoir, operating passage means connecting said fluid reservoir to said cylinder means, valve means controlling flow of lluid between said cylinder means and said uid reservoir, pump means to pump fluid from said reservoir into said cylinder means to extend said ram means, bypass passage means connecting said cylinder means to said uid reservoir to provide a bypass for returning iluid from said cylinder means to said lluid reservoir, valve means mounted on and movable with said ram means for controlling said bypass passage means, said valve means comprising a sleeve member movably mounted on said ram means for movement between spaced positions and being spaced from said piston assembly, a valve movable to an open bypass position during movement of said sleeve member to one spaced position and movable to a closed bypass position during movement of said sleeve member to the other spaced position, means to normally bias said sleeve member to said other spaced position, and means located in engaging alignment with said sleeve member in a predetermined extended position of said ram means and adapted to engage and displace said sleeve member toward said one position to bypass uid thereafter tending to further extend said ram means.

5. The invention as defined in claim 4 and wherein a portion of said bypass passage means extends through said ram means, a valve seat provided in said bypass passage in said ram means, a valve freely associated with said valve seat and having a portion located for engagement with said sleeve member, and control means provided on said sleeve member and being engageable with said valve to normally seat said valve on said valve seat in said other position and to permit movement of said valve away from said valve seat in said one position in response to increases in pressure of said fluid tending to further extend said ram means.

6. The invention as defined in claim 5 and wherein said valve comprises a ball valve having a portion continually extending outwardly beyond said ram means and said control means comprises a tapered slot accommodating said portion of said ball valve and causing variable inward displacement of said ball valve toward said valve seat in response to movement between said ram means and said sleeve member.

7. In a jacking device, an extendable ram means, piston means mounted on said ram means, cylinder means engaging said piston means and reciprocably supporting said ram means, a fluid system including a pump means and fluid reservoir connected to said cylinder means to cause reciprocation of said ram means therein, fluid bypass passage means connecting said cylinder means to said luid reservoir, bypass passage control means to prevent movement of said ram means beyond a predetermined extended position and maintain said ram means in said extended position during continuous operation of said pump means and continuous delivery of iluid therefrom to said cylinder means, said bypass passage control means comprising sleeve means separate from said piston means and carried by and movably mounted on said ram means, a rst portion of the bypass passage means being formed in said ram means beyond said piston means adjacent said sleeve means, a second portion of said bypass passage means being formed in said sleeve means, said second portion of said bypass passage means being connectible to the rest of said bypass passage means communicating with said uid reservoir at a predetermined extended position of said ram means, valve means connecting said iirst portion of said bypass fluid passage and said second portion of said bypass Huid passage, said valve means being actuable between open and closed positions by relative movement between said sleeve means and said ram means, spring means associated with said sleeve means to normally maintain said sleeve means in a valve-closing position, and abutment means engageable with said sleeve means at said predetermined position to displace said sleeve means relative to said ram means against the bias of said spring means and release said valve means for movement to said open position in response to excess uid pressures being applied to said ram means.

8. The invention as defined in claim 7 and wherein said second portion of said bypass passage means in said sleeve means comprises an annular groove having a tapered wall portion engageable with said valve means, and said sleeve means being movable longitudinally o f said ram means to cause progressive engagement and disengagement of said tapered wall portion with said valve means as said sleeve means moves relative to said ram means.

9. In a jacking device, cylinder means, an extendable ram means reciprocably mounted in saidpcylinder means, one end of said extendable ram means extending beyond said cylinder means for engagement with a load and the other end of said extendable ram means having a piston assembly dividing said cylinder means into upper and lower chambers', said ram means having a smaller outer diameter than the inner diameter of said cylinder means and thereby defining the upper chamber as an annular cavity, means to apply high pressure fluid against said piston assembly in the lower chamber to cause extending movement of said ram means within said cylinder means, bypass passage means connecting said cylinder means to said uid reservoir whereby high pressure fluid being applied to said piston assembly may be bypassed to said fluid reservoir, a rst portion of said bypass passage means comprising a passage extending through said ram means from the area adjacent said piston assembly in the lower chamber to said annular cavity of the upper chamber between said ram means and said cylinder means, a second portion of said bypass passage means including a passage portion connecting said annular cavity of the upper chamber between said ram means and said cylinder means to said uid reservoir and having an inlet opening to said annular cavity longitudinally spaced from the outlet opening of said rst portion of said bypass passage into said annular cavity, valve means mounted in said iirst portion of said bypass passage and being movable therein from a passage-closing position to a passage-opening position, and valve control means slidably mounted on said ram means in said annular cavity and being movable there- With and relative thereto to maintain said valve means in the closed position until said ram means reaches a predetermined extended position, said valve control means being operable in said predetermined position to connect said first portion of said bypass passage means to said second portion of said bypass passage means by sliding movement relative to said ram means.

10. The invention as dened in claim 9 and wherein a third portion of said bypass passage is provided in said valve control means, said third portion of said bypass passage communicating with said rst portion of said bypass portion through said valve means, said thirdv portion of said bypass passage having an outlet port formed in a side surface of said valve control means, said side surface having sliding abutting engagement with the inner peripheral Wall of said cylinder means and closing said outlet port until said predetermined position is reached, said third portion of said bypass passage being connectible to said second portion of said bypass passage when said ram means reaches said predetermined extended position to permit excess high pressure uid being appliedto said piston assembly to flow through said iirst portion of said bypass passage past said valve means through third portion of said bypass passage in said control means to said second portion of said bypass passage and said fluid reservoir.

ll. The invention as dened in claim l0 and wherein: said valve control means comprises a sleeve member in the form of an annular ring, said annular ring having a width substantially equal to the width of said annular cavity between said ram means and said cylinder means, an annular groove formed about the inner periphery of said annular ring and opening toward said ram means, the distance between said valve seat and said ball valve being less than the diameter of said ball valve so that a portion of said ball valve protrudes radially outwardly beyond the outer peripheral surface of said ram means, said groove having a ball abutment surface tapering from a portion of maximum width whereat said ball valve may move freely oi of said seat to a portion of minimum Width Whereat said ball valve is held in abutting engagement with said valve seat, movement of said annular ring relative to said ram means being confined to substantially the longitudinal length of said groove by abutting engagement With said ball valve, said outlet opening in said third portion of said bypass passage being formed by a radially extending bore intersecting said groove, spring means concentrically mounted on said ram means between said piston assembly and said annular ring and engaging and biasing said annular ring to a Valve-closing position, and abutment means provided at the upper end of said cylinder means to engage said annular ring in said predetermined position and cause sliding displacement thereof against the bias of said compression spring to release said ball valve and permit the flow of high pressure fluid through said bypass passage to said reservoir.

References Cited in the le of this patent UNITED STATES PATENTS 2,409,335 Stephens July 28, 1936 2,520,426 Mueller Aug. 29, 1950 2,625,796 Traut Jan. 20, 1953 2,715,512 Miller et al Aug. 16, 1955 2,851,011 Chasser Sept. 9, 1958 2,863,285 Pomeroy Dec. 9, 1958 UNITED STATES PATENT OFFICE CERTIFICATE CF CORRECTION Patent Noo 3,l34232 May 26U l964 John M Barosko It is hereby certified that error appears in the above numbered patent requiring correction and that the said. Letters Patent should read as Corrected below.

Column 6Y line 63, after "whereins" insertI said valve means comprises a valve seat provided in said first portion of said passage means and a ball valve freely associated with said valve seat, and

Signed and sealed this 12th day of January 1965.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents ERNEST w.: swIDER ttestng Officer

Claims (1)

1. 4. IN A JACK, CYLINDER MEANS, AN EXTENDABLE RAM MEANS HAVING A PISTON ASSEMBLY RECIPROCABLY MOUNTED IN SAID CYLINDER MEANS, A FLUID RESERVOIR, OPERATING PASSAGE MEANS CONNECTING SAID FLUID RESERVOIR TO SAID CYLINDER MEANS, VALVE MEANS CONTROLLING FLOW OF FLUID BETWEEN SAID CYLINDER MEANS AND SAID FLUID RESERVOIR, PUMP MEANS TO PUMP FLUID FROM SAID RESERVOIR INTO SAID CYLINDER MEANS TO EXTEND SAID RAM MEANS, BYPASS PASSAGE MEANS CONNECTING SAID CYLINDER MEANS TO SAID FLUID RESERVOIR TO PROVIDE A BYPASS FOR RETURNING FLUID FROM SAID CYLINDER MEANS TO SAID FLUID RESERVOIR, VALVE MEANS MOUNTED ON AND MOVABLE WITH SAID RAM MEANS FOR CONTROLLING SAID BYPASS PASSAGE MEANS, SAID VALVE MEANS COMPRISING A SLEEVE MEMBER MOVABLY MOUNTED ON SAID RAM MEANS FOR MOVEMENT BETWEEN SPACED POSITIONS AND BEING SPACED FROM SAID PISTON ASSEMBLY, A VALVE MOVABLE TO AN OPEN BYPASS POSITION DURING MOVEMENT OF SAID SLEEVE MEMBER TO ONE SPACED POSITION AND MOVABLE TO A CLOSED BYPASS POSITION DURING MOVEMENT OF SAID SLEEVE MEMBER TO THE OTHER SPACED POSITION, MEANS TO NORMALLY BIAS SAID SLEEVE MEMBER TO SAID OTHER SPACED POSITION, AND MEANS LOCATED IN ENGAGING ALIGNMENT WITH SAID SLEEVE MEMBER IN A PREDETERMINED EXTENDED POSITION OF SAID RAM MEANS AND ADAPTED TO ENGAGE AND DISPLACE SAID SLEEVE MEMBER TOWARD SAID ONE POSITION TO BYPASS FLUID THEREAFTER TENDING TO FURTHER EXTEND SAID RAM MEANS.

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