US1520842A - Jack - Google Patents

Description

H. C. NEWMAN JACK Filed June` 28, 1921 2 Sheets-Sheet l JWM/ iff

Dec. 30, 1924. LSZQML H. c. `Nl-:WMAN

JACK

Filed June 28, 1921. 2 SheetsfSheet 2 f7 w 55/ /Jf lt further relates to 3 Patent4 Dec. 30, 1924.

`HARRY C. NEWMAN, F LOS ANGELES, CALIFORNIA, ASSIGNOR OF ONE-THIBDA`T0 H. D. EBERLE AND ONE-THIRD TO SPENCER C. ROGERS, BOTH OF LOS ANGELES, CALIFORNIA.

Jaen.

Application filed June 2B, 1921. Serial No. 481,136. i

To all whom it may concern.' v

yBe it known that I, HARRY C. NEWMAN, a citizen of the 'United States, residing at Los Angeles, in the county of Losl Angeles and kState of California, have invented a new and useful J ack, of which the following is a specification.

M .invention relates to jacks and is particular y applicable to jacks which are usedl to raise the axles of automobiles and trucks.

'aeks operating on the principle of hydraulic pressure, oil being used, however, as the vpressure matter.

The Vprincipal object of the invention is to. provide' a jack which will. have a very great mechanical strength and one in whic leakage of oil will be almostl entirely prevented.

A further object is to make a jack which can be very. cheaply constructed of relativelyinexpensive materials. t v

Further objects and advantage will be made evident hereinafter. l

Referring tuo the drawings which are for illustrative purposes only, i

Fig. 1 is a cross section through a preerred embodiment of my invention.

Fig. 2 is a side elevation thereof.

Fig. 3 isasectionon a plane represented by the line 3-i-3 of Fig. 1.

Fig. 4 is a partial section through the by-pass valve. v

Fig.v 5 is an end viewof the handle.

Fig. 6 is an enlarged view showing the large piston in longitudinal section taken on line6-6 of Fig. 7, and the small piston in elevation. v l

Figf( is a. cross sectionof the large piston taken on line 7--7 of Fig. 6.

In the form of the invent-ion shown, 1 provide a base 11 which is preferably formed of cast iron land in which is secured a reservoir casting'v 12, this casting beingl threaded at 13 into a central recess l formed in the base 11. The casting 12 consists of an inner wall 14 in the form of a cylinder and an outer wall 15 which walls are separated by an oil space 16, but are formed integral with each other at their upper ends. A lap joint 17 is provided where the wall 15 joins to the base, the base being provided with a lip 18 fitting inside the wall 15 and'maki'ng an oil tight joint therewith. Threaded in a. cavity 19 in the base 11 is a pump cylinder 20 in'which a plunger 21 is free to reciprocate, this plunger being pivoted'on a pin 22 in a lever 23 which is pivoted upon a pin 24 carried in a link 25 which is in turn pivoted on a pin 26 carried on the casting 12. The lever. 23

is provided with a cylindrical end 27 having a pin 28 therein, this end being engaged by a handle 29 which has the form shown in Fig. 5. The handle 29 consists of a hollow tube having a bayonet type slot v30 formed therein. p 'f The lower end of the cavity 20 communicates with. the lower end of the cavity 13 through a cored passage 35, a hall 36 being seated in this passage in such a manner as to allow oil to pass from the passage into the cylinderr 37 formed inside the wall 14, but to prevent any liquid Vfrom passing into the passage 35 from the cylinder 37, the ball 36 is held invplace with a' screw plug 38. A ball 40 held upwardly by a spring 41 against a seat formed on a plug 42 -closes apassage between the space 16 and `the passage 35 1n such a mannerthat liquid may pass from the space 16 into the passage 35, but is prevented by the ball 40 from passing from thepassage 35 into the space 16. A by-pass passage 45 is provided in the base ,1.1 connecting the space 16 with the cylinder 37, this passage being closedl by kthe end 46 of a threaded stem 47 which isi provided on its. outer end with a pin ,48 whlch may be engaged by the handle 29. f

l lhe inner surface of the wall 14 is machrned to form a cylinder and a large is- 4ton 50 is free to. slide therein, being provi ed with a cup leather 51 secured by a nut 52.

l The nut 52 has an opening 53 therein so that oil may pass from the cylinder 37 into the space 54 inside the large piston 50. The large piston is provided with longitudinal grooves 55 formed on the outer surface thereof, these' grooves extending from a point 56 -to a point 57.Y Small holes 58 are drilled through the large piston 50 communicating 'with grooves 55. A brass tube 59'is threaded at 60 to the large piston 50 and A stufling box extends down to a point 61. consisting of packing and a nut 66 makes a tight jointbetween the upperl portion of the member 12 and the tube 59, holes 67 being drilled the wall 14. Sliding in the cavity 54 'is a small piston 70 which carries a stirrup V'I' 1 on its upper endupon which the load to be lifted is supported.

A cu leather 72 is carried on `the lower endothepiston70.

The method of operation of the-invention is as follows: The spaces 54 and 16 and the cylinder 3,7 are filled with oil with the piston 50 and the piston 70 at their lowest position as shown in Fig. 2. The passage is closed by the member 46. The plunger 21 is re- .ciprocated by means of the handle 29 each up-stroke taking oil from the space 16 past the ball 40 and each down-stroke forcing this oil past the ball 36fin'to the cylinder 3 7. Thisbu'ilds up a iuidpressure in the cylinder 37 andspace 54' and this pressure ex erted upwardly upon the lower end of 'the large piston tends to raise same, the piston remaining in its lower position in the piston 50 but being carried upwardly thereby. Any oil which may leak past the cup leather 51 passes through the hole 67 into the space 16. Any oil leaking ast the cup leather 72 passes through the oles 58 tlirough the grooves 55 and through the holes l67 intothe space 16. The upward movement ofthe piston 50 continues until the shoulder "100 strikes against a Washer lac thereafterfoperates by raising the piston 7()` to. thegliinit of its movement; This gives a veryflongi stroke fora shortijack and also givesLa very great power dueI tothe fact that the leverage lis greatly multiplied duc to the small` area of theplunger 21 as com- `pared to the areas of the pistons 50 and 70 -and also due to the long leverage provided by the handle 29. -Whenever it is desired to "lower the weight, this'can be done. by turning .the

screw 47 and allowing ioil to leak back into the space 16 from the cylinder 37 through the passage 45. This leakage of the oil can be accurately/regulated so the load comesdown s lowl and thisdownward movement ofthe loa can be instantly arrested by closing the passage 45 of the member 46.

Particular attention is called tothe conv struction of the member 12 which is extremely rigid, the threads holding it solidly down into the base 11 andthe member 12 being further "supported at; the point 17. The member 12 is ill-the form cfa casting which is provided -jwith' stiften-ing ribs 110 between the walls 14 and 15,v .these stilening ribs making the member 12 very rigid.l As

the cavity 16 `is-cored out, the member 12 is extremely cheap to'nake land renders this type of jackcommercially feasible. I claim as my invention:

A jack including: a cylinder closed at its lower end andhavin portsin its wall near its upper end; a ho low piston including a head on its ylower end slidable in said cylinder in fluid-tight contact therewith, said iston having a portin its head and ports 1n its upper end' a stuffing box on the upper end of said cylinder through'which said piston extends; a tube surrounding said piston and extending -dovvnwardly throughv said stuffing box in fluid-tight contact therewith, thefupper end of said tube being secured to the upper end of said piston, there being a fluid return space formed between 'said piston and saidjtube, the upper end of said space communicating With said ports in the upper end of said piston, said return Y.

space bein in open communication with the interior o said cylinder at a point above said piston head and below said stuing box; a second piston slidable inside said hollow piston; a iston rod secured to said second piston projecting upwardly outside said first piston; and a closureabout said piston rod at the upper end of said first piston.

In testimony whereof, I have hereunto set myhax'u at lLos Angeles, California, this 21st day of June, 1921'.

HARRY C. NEW if@ L

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