US1720434A - Fluid-operated jack - Google Patents

Description

. mmm

y H29, T. w. PEDERSEN FLUD OPERATED JACK [filed Dec. 5, 1924 ZSheetS-Sheet l T. W1J PEDERSEN MAIM FLUID OPERATED V.mmm

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\ a um Patented July 9, 1929.

UNITED STATI-:s

PATENT OFFICE.

THOMAS W. PEDERSEN, OF NEW YORK. N. Y., ASSIGNOR TO OIL JACK, INO., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

FLUID-OPERATED J ACK.

Application filed December 5, 1924. Serial No. 754,118.

. This invention relates te improvements in fluid-actuated jacks, and more particularly to jacks that are self-contained and include means i'or storing the. actuating (luid.

The principal object ot the invention is to provide ay jack ot? this type which shall be generally more ellicient and durable than Others and shall be considerably less expensive to manufacture.

Another (,)bjcct is to provide. a fluid-operated jack with means for positively preventing the forcing ot' the jack stem 'trom the cylinder.

A further object of fthe invention is to provide a {luid-operated jack which shall .be leak-proof and which may be carried in any position without loss of l'luid.

'The invention further resides in certain novel and advantagi-ious details ot construction as hereinafter set forth and as illustrated in the attached drawings, in which:

Figure 1 is an elevation of a jack made. in accordance with my invention;

Fig. 2 is a plan view ot the jack;

Fig. 3 is a section ou the line 3 3, Fig. l, and

Fig. 4 is a fragmentary section on the line 4 4, Fig. 2.

With reference to the draw-ings, my jack comprises an integral body member l which may be of cast metal, said body having a niain chamber 2 and a cylindrical sub-chamber 3 whose function will be described hereinafter. rl`he chamber 2 has at the bottom a central cylindrical recess or depression -1 for reception of the lower end 0i" a cylinder 5 constituting the main cylinder of'the jack -in which the stem 6 operates;

A valve fitting 7 also occupies a position in the recess 4, said fitting lying within the lower end of the cylinder 5 and having a reduced externally threaded extension S extending down into a correspondingly threaded recess 9 at the bottom ofthe recess 4.

r lvith the threaded extension 8' the fitting 7 may be screwed down upon a cup-leather or other suitable packing 10 in the bottom of the recess 4.

The fitting 7 is provided Wit-h a central passage l1 which opens at the top into a recess l2, the passage 11 at: the point where it enters said recess being flared or otherwise formed to provide a seat for a ball valve 13 which normally closes the said passage 1l. A rod lst extemling across the top of the ret-ess 12 prevents dislodgment of the ball 13 from its chamber.

As shown in liig. il, the extension S of the litt-ing 7 does not reach the bottom oli the recess 5), wherelrv a space 15 is let't; below the ttting with which the passage ll. ronununicates, and a passage 1G establishes` communication between the said space 'l5 and the bottom of the chamber 3. lu the present instance, the passage 1G extends beyond the chamber 3 to the outside ot' the body 1. The outer end of the passage 1G may be closed. by a set screw 17 or other suitable preferably detachable element.

The cvlinder 3 is recessed at the bottom tor the reception of a ball valve 18, the latter linding a seat in the bottom of the recess 1t), from which a passage 20 extends to the. bottom ol" the chamber 2 outside of the cylinder 5, as shown in Fig. 2l. The valve 18 normally closes that end of the passage which opens into the recess 19.

'lhat portion of the body 1 enclosing the chamber 2 is provided at the top with a threaded opening 21 through which the top of the stem or ram 6 projects, and threaded into this opening 2l is a sleeve 22 having au annular recess 23 in its under side vlor reception ot the upper end of the cylinder 5 whereby when thc said sleeve 22 is screwed down into place against the top of the cylinder, the latter is clamped in proper position within the body l, seated at the, bottom in the said recess 4 and held at the top w2ithin the annular recess 23 of the sleeve 2 The cylinder 5 is provided at its top with a slot or other suitable opening 2i which establishes communication between the interior of the cylinder and the space 25 ext'erioro't. the cylinder which, as hereinafter set forth, constitutes a reservoir for the operating fluid. l i' As shown in Fig. 3, the ram or stem 6 is, over the greater portion of its length, slightly smaller than the inside of the cylinder 5, but has at. the bottom a section 2G ot increased diameter neat-ly titting'said c'vlinder, this section guiding the ram in the cylinder. The steml 6 is provided at the bot-A.

tom with a recess 27 threaded at its lower end for reception-of a threaded extension 28 on. a valve fitting 29. The stem is further provided at the top of the section 26 with a cross channel 3() which extends diametrically through the stem and through the upper end of the recess 27'. cross or contact bar 31, whose length is a'pproximately the same as the diameter of the stem-section 26, and which is suitably engaged with the upper end of a valve actuating stem 32 which extends loosely through a central opening 33 in the fitting 29. The stem 32 is adapted to engage with its lower end a ball valve 34 seated in the upper end 'of the lower enlarged section 35 of the opening 33 and'normallyretained on its seat by a spring 36 confined in the said section 35 by a stud 37 threadedl into the fitting. A sex-.ond spring 38 is confined in the top of the recess 27 and functions normally to hold the stem 32 and .bar 3l inA an elevated position', as shown in Fig. 3, in which position the ball 34 is seated and closing the opening 33. A

cup or other packing 39 is held between the tting 29 and the bottom of the st'em 6.

To prevent leakage of the actuating fiuid at the top of the chamber 2, suitable packing material 40 `may be inserted in the opening 21 aboveq the sleeve 22 and surrounding the stem 6, and a gland 41 may then be threaded down into said opening to compress and expand said packing. The upper end 42 of the stem 6 is, in the present instance, threaded for reception of a loadengaging head 43.

The Achamber 3 is cylindrical in form and constitutes a pump cylinder, and is adapted for reception of a pump piston 44, to the bottom of which is secured by a screw 46,

a suitable packing element 45. The piston extends upwardly through a suitable packing box-47 in the top Aof the chamber 3 and connects at the top with a pump lever .48, see Figures 1, 2 and 3. The pump lever 48 is pivotally secured to a boss 49 on the body 1, by means in the present instance of a screw 50, and is connected with the piston 44 through a link 51 the 'ends of which are pivotally attached to the respective connected arts. p As shown in Fig. 4, .the cylinder 5 is provided with a port 52 at a point immediately above the top of the valve fitting 7, said port opening into the reservoir 25. The port 52 is-adapled to be closed by a needle valve 53, which extends through an opening 54 in the body 1, the stem of said valve being threaded into a hollow stud 55 which latter is in turn threaded into the opening 54. The stud 55 is adapted to receive packing'material which is confined by a gland 57 threaded into the outer end of the stud, leakage around the valve stem being thus prevented. The outer The channel, 30 receives a v projecting end of the said stem is provided with a suitable head 58 by which the valve may be adjusted to close or uncover the port 52.

" As will be apparent, the actuating fluid is 'normally contained in the reservoir 25, and operation of the pump piston 44 by means of the lever 4.8 will cause this fiuid first to be drawn into the bottom of the pump chamber 3 through the. passage 20, and thereafter on the down stroke of the pump to be forced through the passage 16 and valve 13 into the bottom lof the cylinder 5. In this manner, the stem 6 may be elevated until the ends of the bar 31 strike the under side ofthe sleeve 22, whereupon the valve 34 will be opened by depression of the bar 3l, with the result that a by-pass is provided for the fluid from below the stem 6, through the opening 33 of the fitting 29, the channel 30, upwardly around the stem 6, and through the port 24 to the reservoir 25. Continued pumping merely circulates the fluid without ailecting the pressure on the stem 6.

.During elevation of thestem 6, the nee' lle valve 53 is closed, and when it is desired to return the' stem to its normal position, as

shown in Fig. 3, the needle valve may be adjusted, as previously described, to uncover the port 52, thereby permitting the fiuid to pass from the. cylinder 5 back into the reservoir 25.

- It will be apparent that my improved ack, by reason of the integral construction ot the body, base and pump cylinder, made possible by the use of the removable cylinder 5 and the means for holding the latter in position,

is inexpensive to manufacture. The constructionis also such as to render assembling the' jack easy, thereby further reducing expenseof manufacture. It will further be noted that all openings by reason of the improved construction m'ay be effectively packed against leakage, which at the top of the cylinder' is further guarded against by provision of 4the vent 24 through which leakage past the' bottom of the stem may be drained backinto the reservoir. Provision 0f the valv'ed by-pass for the fluid, functioning after the stem 6 reaches the top of its -travel, also is of marked advantage-as preventing undue pressure in the pump with possible breakage of the parts and forcin of the stem Afrom the cylinder. i

It is, obvious that the jack as herein described may be considerably modified in detail without departure from the essential features of the invention as defined in the appended claim.

I claim:

A fluid opera-ted jack comprising a casing enclosing a reservoir; a recess in the base of said reservoir; a cylinder fitting into said recess and extending through said reservoir; a-stem in said cylinder of a diameter smaller Mylan the internal diameter of the ylinder; a?. enlarged guide portion on said stemslidably tting said cylinder; a bushing slidably fitting said stem and screwed into an open- 5 ing in the reservoir casing for retaining the cylinder; a packing gland screwed into the same opening in the reservoir casing; an

`aperture in the cylinder connecting the annular space between the stem and cylinder with 'the reservoir; a, pump; and means for concylinder. v

THOMAS W. lPEDERSEN.

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