US1951398A - Hydraulic jack - Google Patents

Description

March 20, 1934. l

l. E. DEARSLEY l nYDRAuLI .mex

Filed Dec. 7.1952

4 Sheets-Sheet 1 March 20, 1934- l. E. DEARsLEY.

HYDRAULI C JACK Filed Dec. 7. 1932 4 Sheets-Sheet 2 March 20, 1934. l. E. DEARSLEY HYDRAULIC VJACK Filed uw. v. 1952 4 Sheets-Sheet 5 March 2o, 1934. l, E, DEARSLEY- 1,951,399v

HYDRAULIC JACK Patented Mar. 20, 1934 UNITED STATES PATENT oFFl'cE HYDRAULIC JACK Irwin E. Dearsley, Racine, Wis., assigner to Walker Manufacturing Company, a corporation of Wisconsin l Racine, Wis.,

Application December 7, 1932, Serial No. 646,129

4 Claims. (Cl. 13S-9) when lowered, and a relatively long lift in pro-1v portion to this initial height. The jack is also provided with a double pump mechanism which acts automatically as the operating handle is reciprocated so that the lifting member of `the jack will -be quickly elevated into engagement with the load by the combined action of the two pumps, and will then be more slowly elevated by one of the pumps after the load has been accepted.

The principal object of this invention is to provide an improved jack of the type briefly described hereinabove and disclosed more in detail in the specications which follow. Another object is to provide an improved transportable hydraulic jack having a minimum height when lowered so that it may be positioned under low loads.

Another object is to provide a jack of this type in which the operating mechanism is protected by the lifting-arm when lowered.

Another object is to provide an improved twospeed hydraulic pump mechanism.

Another object is to provide improved means for rendering a high-speed pump ineffective when a predetermined load has been accepted.

Another object is to provide improved means for guiding a ram and limiting the outward movement thereof.

VAnother object is to provide an improved operating handle mechanism for actuating the pumps and controlling the release valve.

Other objects and advantages of this invention will be more apparent from the following detailed description of one approved form of apparatus constructed and operating according to the principles of this invention.

In the accompanying drawings:

Fig. 1 is a side elevation of the jack in lowered position, an intermediate portion ofthe operating handle being broken away.

Fig. 2 is a plan view on a larger scale of the operating handle, partially broken away.

Fig. 3 is an enlarged plan view of the jack, with the handle broken away, and some portions of the superstructure broken away to disclose underlying members. V

Fig. 4 is an inside elevation of one of the side frame members with its supporting rollers.

Fig. 5 is a vertical Vlongitudinal section, taken just inside the frame member 1 and looking toward the opposite side of the jack. v

Fig. 6 is a partial longitudinal vertical section, taken substantially on the line 6-6 of Fig. 3.

Fig. 'I is a transverse vertical section taken substantially on the line 7-7 of Fig. 6.

Fig. 8 is a partial longitudinal vertical section taken substantially on the line 8-8 of Fig. 7.

Fig. 9 is a similar vertical section taken substantially on the line 9-9 of Fig. '7.

Fig. 10 is a partial transverse vertical section taken substantially on the line 10--10 of Fig. 6.

Fig. 11 is a transverse vertical section taken substantiallyon the line 11-11 of Fig. 6.

Fig. 12 is a detail vertical sectiontaken substantially on' the line 12-12 of Fig. 1.

The carriage comprises a pair of similar side frame members l and 2, each of which has a maximum height adjacent its rear vend 3 and tapers downwardly toward `its front end 4. The forward ends 4 of the side frames are provided with hubs 5 which are pinned at 6 on a transverse shaft 7 which supports the frame members and spaces them apart. Rollers 8 are mounted on the projecting end portions of shaft 7 and held in place by cotter pins 9. A pump-,block or casting 10 is rigidly secured between the rear portions of the side frames 1 and 2 by a bolt 12 extending transversely through the upper rear portion of the block and side frames with nuts 12 screwed on its projecting ends, and screw bolts 13 projecting through the side frames and screwed into the lower portion of the casting. The upper and forward portions of the block 10, have a lateral thickness considerably less than the width of the space between the side frames 1 and 2, so that spaces remain between the block4 and the side frames to receivey the lifting levers and links, as hereinafter described. A vslip shaft 11 extends through the lower rear portions of the block 10 andthe side frames 1 and 2, and rollers 11' are mounted on the projecting end portions of this shaft and held in place by cotter-pins 11". A ram-cylinder 14 inthe form of an open ended. sleeve is rigidly supported from block 10 by having its rear end exteriorly threaded and screwed into the block, as indicated at 15. The cylinder 14 projects forwardly from the pump block sub-J stantially horizontally, or may be inclined downwardly at aslight angle, as shown in Fig. 6. An annular head 16 is screwed at 17 onto the outer end portion of cylinder 14- and serves to clamp in place a' larger hollow sleeve 18 which surrounds the ram cylinder 14 and ts at its ends cent these side frames.

into recesses provided therefor in block 10 and head 16, respectively. The annular space between the sleeves 14 and 18 serves as a reservoir 19 for the oil or other liquid used as an operating `medium in the cylinders. A screw-plug 20 mounted in the top` of sleeve 18 normally closes an opening through which the supply of oil may be replenished. An air-vent 21 formed in plug 20 is closed by a screw plug 22 when the jack is shipped, this plug 22 being removed when the jack is in service. A ram 23 is slidable through a packing 24 positioned in head 16 at the end of cylinder 14Vand held in place by a gland 25 screwed into the end of head 16. A suitable piston'26 of well known type is mounted at the inner end of ram 23 to maintain a liquid tight fit with the interior of cylinder 14.4 The forward end of ram 23 is split or recessed to form a yoke, the side arms 27 of which embrace a cross-head 28 tol which thearms are pinned or riveted at 29. Rollers 30 are pivotally mounted on the reduced end portions 31 of the cross-head, these rollers 30 operating in the guide-ways or channels 32 formed in the inner faces of the respective side frames 1 and 2. Stop ribs 33 are formed on the side frames adjacent the forward ends of these guide-ways for a. purpose hereinafter described.

The load-lifting bell crank 34`is in the form of an inverted channel member having a width approximately equal to the width of the space between the side frames 1 and 2 and having' its side anges 35 extending downwardly adja- The bell crank is fulcrumed adjacent its rear upper end on the pivot pin 36 extending transversely through the highest portion of the side frames and locked in place by the nuts 37 screwed on its threaded end pcrtions. A pair of similar links 38 are pivot-ed at their forward ends on the cross head 28 and are pivotally secured by pins 39 to the respective downwardly and rearwardly extending end por'-,

tions 40 of the side anges 35 of bell crank 34. The forwardly projecting 'ears 40 at the front end of bell crank 34 are pivotally connected by pin 41 at the outer sides of downwardly projecting ears 42 on the load lifting head 43. It will now be seen that the side flanges 35 of channel member 34 virtually form a pair of bell-cranks connected togetherv to operate in unison'by. the top web 50 of the channel, each bell-crank com.- prising a short arm projecting downwardly between the pump-block and the adjacent sidevfraV me, and a long forwardly projecting lifting arm. The load-supporting head 43 is provided with a plurality of upwardly projecting fingers 44 adapted to engage the load, and is formed witha central opening 45 vwhich may receive .a downwardly projecting portion of thev load. A pair of similar parallel-motion links 46 are pivoted at their front ends on pin 47 between the ears 42 ofthe load-supporting head and are pivoted at their rear ends cna pin 48 extending horizontally through a boss 49 formed on the upper front portion of pump block 10. The distance between pivotal axes 36 and 48 is substanj tially the same as that between axes 4l and 47,

and the links 46 are of substantially the same length as the portion of bell crank 34 between the axes 41 vand 36 so that the links 46 and lever 34 will swing substantially parallelto one another and the load-supporting head-i3 will remain substantially horizontal at all elevations. It will be noted that all -of the links 38 and 46 are housed beneath and within the channel.

height. The underlying members are also protected by the top plate or web 50 of the channel member 34 so that the jack will have a neat and pleasing appearance and be substantiallyv enclosed when in lowered position, as shown in Fig. 1. The cover plate 5 0 will also serve to protect the underlying parts in case the loador any vother object should fall upon the jack.

The forward end portions of links 38 engage the stop ribs 33 to limit the upward movement of the load-lifting members and the vforward movement of the ram.

When oil or other liquid is forced into the ram cylinder 14 (in the manner hereinafter described), the ram 23 will be projected forwardly, thereby pulling the links 38 forwardly and swinging the bell crank 34 up to the position shown in solid lines in Fig. 5. 4When the oil is permitted to flow out of ram cylinder 14, the p arts will be returned to the position shown in dotted lines f in Fig. 5, and in solid lines in the other figures of the drawings, by the load resting on head 43 and the weight of the elevated parts. To insure the complete lowering of the jack after the load has been disengaged, retraction springs 51 are secured at their forward ends 52-to the cross head 28 and at their rear ends 53 to the respective side frames 1- and 2 adjacent the anchoring bolts 13. These springs will be extended when the load is elevated and will serve to return all of the parts to the lowered position even though there is no load on the supporting head 43.

A pair of similar substantially horizontal pump cylinders 54 and 55 extend inwardly thro-ugh the rear end of block or casting 10. The cylinders are of similar length but cylinder 54 is of considerably larger diameter than cylinder 55. A piston 56 is slidable in cylinder 54 through a packing 57-held in place in the outer end of the cylinder by means of glandV 58. A suitable cuppacking 59 is secured on the inner end of piston 56 to form a iluid tight joint between the inner end of the piston and the walls ofthe cylinder. An exactly similar piston assembly 60, but of smaller diameter, is mounted in the other pump cylinder 55.

The operating handle comprises a hollow casting 61 fulcrumed on pivot pin 62 mounted in the rearwardly projecting ears 63 at the rear ends of side frames 1 and 2. A downwardly projecting short arm or crank extension 64 formed on casting 61 carries a cross pin 65 which v6.8 and 69 which are secured at their rear ends to the opposite sides of the casting 61 by transversely extending pins or rivets 70. The bars 68 and 69 converge rearwardly and are secured at their rear ends by bolts 71 and 72 to the opposite sides of the forward end of a fiat bar 73. A pair of similar semi-cylindrical wooden handgrip members 74 having rounded end portions are secured to the opposite sides of the free rear end portion of bar 73 by means of screws 75. An upright bracket member 76 is centrally looped to enclose the three bar members 68, 69 and 73, being secured thereto by the bolt 72 (see Fig. 12). The bracket 76 comprises adownwardly projecting leg or rest 77 which is adapted to support the handle in its extreme lowered position,

as shown in Fig. 1. An upwardly projecting boss 78 formed on the top of bracket 76 is perforated to form a bearing 79 for the rotatable operating rod or shaft 80, hereinafter described. The casting 61 isfprovided with an upwardly and forwardly projecting lip portion 81 adapted to engage an upper portion of block 10 to limit the upward swinging movement of the handle. This also provides a means whereby the rear portion of the carriage may be lifted from the ground by means of the handle so as to facilitate maneuvering the jack.

A longitudinally extending oil passage 82 formed in the lower portion of pump casting 10 communicates at its forward end with the reservoir 19, and conmiunicates intermediate its ends with a transverse conduit 83. A passage 84 extends downwardly through the .upper portion of casting 10 in front of pump cylinder 54, this passage being closed at its upper end by screw plug 85. A lateral passage 86 leads from passage 84 into the ram cylinder 14. Aball Valve 87 engages a valve seat 88 formed at the lower end of passage 84, the ball being normally held against its seat by the spring 89 confined between the ball and the screw plug 85. A smaller passage 90 extends downwardly below valve seat 88 and communicates through lateral passage 91 with the pump cylinder 54. The lower end of passage 90 communicates with the transverse passage 83, already described, and a ball valve 92' is normally held against seat 93 at the lower end of passage 90 by means of spring 94 confined between the two balls 93 and 87. An exactly similar set of valved passages connects the other pump cylinder with the supply conduit 83 and the ram cylinder 14, all as shown in Fig. 9.

On the rearward or suction stroke of either one of the pump pistons, the valve 92 will be lifted and oil will be drawn from the reservoir through passages 82, 83, 90 and 91 into the pump cylinder 54 or 55. On the forward stroke of the piston, valve -92 will close and Valve 87 will open to permit this oil to be forced from the pump cylinder through passages 91, 90, 84 and 86 into the ram cylinder.

A discharge passage 95 leadsrearwardly from ram cylinder 14 and communicates with a vertical passage 96 which leads down into transverse Aconduit 83. The discharge passage 95 is normally closed by a longitudinally movable Valve 97 carried at the forward end of a valve rod 98 slidable in the passage 99 formed in block 10. A rotatable valve-operating rod 100 engages the reciprocable valve rod 98 at its forward end, and is threaded at its rear portion 101 to screw into a correspondingly theaded opening in the annular plug 102 which is screwed into block 10 against a packing 103. A universal joint 104 connects the rear end of rotatable valve-operating rod 100 with the forward en d of the rotatable valve-operating shaft already described. This shaft 80 extends rearwardly vand upwardly through the operating handle and is rotatably and slidably supported adjacent its rear end in the boss 78 of bracket 76, as already described.

Shaft 80 is provided on its rear end with a laterally extending operating crank orv handle 105 which will be in the position shown in Figs. 1, 2 and 12 when the valve 97 is closed. This will be the position of the parts when the jack is being permit the valve 97l to be forced .away from its valve seat, thus permitting a restricted ow of l oil from the ram cylinder 14 through passages 95, 96, 83 and 82 back into the reservoir 19. This lowering movement may be stopped at any time or suitablyrestricted by the proper manipulation of handle 105 and valve 97.

A by-pass passage 1 06 leads from the forward end portion of cylinder 54 into the central horizontal discharge passage 82, (see Fig. 7). A ball Valve 107 is 'normally held against a valve seat 108 at the discharge end of by-pass 106 so `ras to prevent the flow of oil through this passage. Ball valve 107 is normally held closed bythe spring 109 confined between follower 110, slidable in passage 111 and an adjustable screw plug 112 threaded in the outer portion of passage 111. The exposed end' of passage 111 is normally closed by disc orplug 113. By adjusting the screw plug 112 in or out, the compression of spring 109 may be adjusted so as to determine the pressure at which ball valve 107 will open. Inv

an exactly similarmanner, a by-pass 114, 115 extends from the inner end portion of pump cylinder 55 to the discharge passage 82, (see Figs. 9 andy 10.) This by-pass is normally closed by the safety ball valve 116 held in pla/ce by adjustable spring 117 in the same manner as valve 1.07,

already described. Valve 107 is adjusted to open at a much lower pressure than valve 116, as will be hereinafter apparent.

During the initial elevating operation, before they load is encountered, both pumps will operate simultaneously to force oil from the reservoir 19 into the ram cylinder 14, and since pump 55 is of considerable capacity, the lifting arm 34 will be very rapidly elevated until the load is engaged. After the load is engaged by the l'fting head 43 (if this load is of considerable weight), the consequent resistance to the -j'forcing of liquid into the ram cylinder 14 will be greater than the pressure for which the ball valve 107 is adjusted so that this valve-will open during thevoperative stroke of piston 56 and the oil drawn into the larger pump cylinder 54 will be discharged through by-pass 106 back into/#the reservoir. In other words, the larger orrhigh-speed pump will be ineffective as soon as a certain predetermined maximum load is imposed on theram and lifting mechanism. However, the ball valve 116 controlling the by-pass from the smaller or lowspeed pump 55 is adjusted so as to normally remain closed so long as the load on the jack is noty in excess of the safe load to be handled thereby. Accordingly, the smaller pump 55 will continue to operate to force liquid into the-ram cylinder 14 and elevate the load. Pump 55 is so designed that the load may be elevated without applying excessive force to the operating handle. be seen that the operating handle may be oscillated continuously -and the lifting head 43 will be elevated rapidly until the load is engaged and controlling the'by-pass from pump 55 is merely a safety valve and remains closed at all times unless an excessive load is imposed on the jack or- It will thus attempt is made to operate the pump after the jack has been completely elevated. At such times the valve 116 will open to permit oil to flow directly from cylinder 55 back to the reservoir without causing injury to the operating mechanism.

'When' the jack is to be lowered, this is accomplished by swinging over the handle 105 of rotatable shaft .80 to open the valve 97, in the manner already described. The retraction springs 51 insure a complete lowering of the jack after valve 97 has been opened, even though there is no load on the jack.

universal joint 104 is not located directly on the pivotal axis of the operating handle, there will be a slight longitudinal movement of .valve-operating shaft through bearing 79 as the operating handle is oscillated. 'I'his will have no effect on the release-valve 97 since this valve can only be operated by a rotary movement of the operating shaft.

It will now be seen that this jack is extremely compact, and easy to maneuver into position under Very low loads; A two-speed operating mechanism is provided which operates entirely automatically so that` by merely oscillating the operating handle the jack will be quickly elevated into engagement with the load, and the yload will then be raised at a much slower` rate so that a heavy load may be handled easily and safely without undue exertion. a l

I claim:

1. In a hydraulic jack, a carriage `comprising longitudinal side frames, a horizontally positioned pump-block rigidly connected between the vrearlower portions of the side frames, a ram cylinder projecting forwardly from the pump block, a ram slidable in the cylinder, a lifting bell-crank in the form of an inverted channel, the bell-crankbeing s fulcrumed between the upper portions of the side frames above the vpump-block with the side flanges of the channel projecting downwardly adjacent to and between the side frames and at the sides of the block,

a lifting head at the free end vof the bell-crank,v

bell-crankin the form of an inverted channel,

the bell-crank being fulcrumed between the upper portions of the side frames above the pump-block with the side flanges of the channel projecting downwardly adjacent to and between the side frames and at the sides of the block, a lifting head pivotally mounted at the free end It will be noted that due to the fact that the .of the bell-crank, links connecting the ram with the lower portions of the side flanges of the channel between the side frames and the block, and parallel motion links pivoted at theirforward ends to the head and at their rear ends to the pump-block and housed within and beneath the channel when the bell-crank is lowered.

3. In a hydraulic jack, a carriage comprising.'

longitudinal side frames, a horizontally positioned pump-block rigidly connected between .the rear lower portions of the side frames, a ram .cylinder projecting forwardly from the pump of the bell-crank, links connecting the ram with',

the lower portions of the side flanges of the channel between the side frames and the block, and v parallel motion links pivoted at their forward ends to the head and at their rear ends to the pump-block, both sets of links being housed Within and beneath the channel when the bell-crank is lowered.

4. In a hydraulic jack, a carriage comprising longitudinal side frames, a horizontally positioned pump-block rigidly connected between the rear lower portions of the sideframes, aram cylinder projecting forwardly from the pumpblock, a ram slidable in the cylinder, a cross-head connected with the forward end of the ram, there being channeled guide-Ways formed in the inner faces of the side frames for receiving the ends of the cross-head, a lifting bell-crank in the form of an inverted channel fulcrumed between the upper portions of the side frames above the pump-block with the side flanges of the Vchannel projecting downwardly adjacent to and between the side frames and at the sides of the block, a lifting head at the free end of the bell-crank,

links connecting.the cross-head with the lower l12( portions of the side flanges of thechannel, stops formed on the side frames adjacent the forward ends of the guideways and engaged by the links

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