US2214440A - Hydraulic jack - Google Patents

Description

p 1940- J. 5. ROTi-IERY ,2

' HYDRAULIC JACK I Filed Feb. 17, 1940 I Ir wentoi' JAMES S. ROT/IERY A homey Patented Sept. 10, l.

James Stewart Bother-y,

London, England, assignor to Servlsales limited, London, England, a

. British company Application February 17, 1940,-Serial No. 319,523

- In Great Britain June 29, 1938 1 concerns more particularly means for locking the jack when. in use to prevent the slow sinking of the ram which sometimes occurs when the load is left on the/jack for a long time and to enable the .oil pressure to be released whilst maintaining the load.

The invention also includes a novel method of storing the oil or other fluid used in the jack as well as details here'inafterdescribed.

The inventionis particularly designed for use as an aeroplane jack but is suitable for use with motor cars and for other purposes where loads are to be lifted and maintained in raised position.

The frame of the jack may be of any desired kind and the pump therefore may be'hand and/or foot operated, or the fluid pressure applied by any other suitable means. s

Themeans according to the invention coma0 prises strut members adapted to be removably applied to the extended ram to make such engagement with the top of the ram (or with an element attached thereto) and with a part of the jack at the cylinder end of the ram as posi- 26 tively to hold the ram against movement into its cylinder; and the-jack according to the invention comprises a combined hydraulic jack and a locking means comprising grooved collars around the ram and strut members adapted to be interposed between and engaged by the collars in such "a manner that the said members" and the collars positively "hold-the ram against movement intoits cylinder. I

The strut members are preferably of semicircular cross section so that when mated in pairs they form tubes but each pair of members is different in length from any other pair so that by appropriate selection of a, pair of members or superposing selected pairs the best locking means for the work in hand can be obtained. Fractional adjustments, i. e., adjustments less than the effective heightois the smallest pair of elements, can be obtained by providing the jack with a screw crutch.

The pump is preferably'mounted on the jack and the frame of the jack is preferably tubular to form the storage chamber for the oil, portions of the frame having. suitable valves to control the oil flow, and a box or bag may \be provided on the frame to hold the strut members and securing means for them if securing means other than elements around the jack ram are used. The invention will now be described with reference to the accompanying drawing'wherein: Fig. 1 is a perspective view pf a jack with its extended ram held against collapse by the present strut members;

. Fig. 2 is a perspective view of a set of pairs of strut members, the scale to which the said members are drawn in this figure being larger than 5 that to which they are drawn in Fig. 1;

Fig. 3 is a sectional elevation of one of the locking collars; L Fig. 4 is a detail, in sectional elevation, of the top of-the ram and certain elements thereat; and 1 Fig. 5 is a perspective view of two mated strut members hinged together.

The framework I of the jack is of tubular form and supports a cylinder 2 and a pump 3. A ram 4 working in the cylinder'is provided with a crutch 5 at its top,'said crutch having a screwthreaded shank 6 which can be'made to enter, more or less, a nut 1 at the top of the ram (Figs. 1 to 4).

The ram is extended by operating the pump.

-I he jack when supporting a load tends to collapse but the jack illustrated is prevented from so doing by the provision around the extended ram of the strut members 8 and the locking colulars 9. The strut members are of semi-cylindrical form. They are pairedbut each pair is of difl'erent length from any'other. The collars 9 are located around the ram and when not in use lie one onv top of another at the cylinder end of the ram, 1. e., ontop of the frame I.

The strut members are applied to the extended j ram by mating the pairs and so manipulating the, collars 9 that the tops'and bottoms of the said struts press against the central, internal flanges 10 of the collars. Inthis manner the collars lock the struts insubstantial contact with theram and against outward collapse, The bottom collar rests on the top of the cylinder 2 whilst the top collarthrusts agalnstthe under- .side of the ,nut'l. If desired, the nut I may be recessed (at H, Fig.4) in its underside to act in a manner analogous to a collar.

. In order to make fractional adjustments, 1. e., adjustments less than the length (the vertical. dimension) of the smallest pair of struts, the. shank 6 fof the crutch is turned so as more or less to enter'the nut I, as previously explained.

The frame "I is made of hollow tubing so connected to the pump that the tubing provides the container for the oil. -Preferably, the cylinderv has an exhaust conduit I2 near its top and the conduit leads to the interior of the tubular frame- .work. Thus, when the ram has made a predetermined out-stroke pressure fluid is ableto leak into the reservoir and further outward movement of the ram stopped.

The framework is provided with a box or bag I I for the struts 8 when out of use.

Each pair of struts instead of comprising two separate members may comprise two members hinged together as shown at l8, Fig. 5.

The crutch maybe of any suitable form known in the art.

What I claim is: $1. In combination with a hydraulic jack iricluding a cylinder, a ram movable in the cylinder, and means operative in the cylinder for elevating the rain, of a pair of semi-cylindrical bodies adapted when correlated to provide members to encircle and substantially contact the ram above the cylinder to provide positive stops beclosed about the ram.

4. A construction as defined in claim 1 wherein means are provided to bear onrthecylinder of the jack to receive and maintain the mating cylinders in proper relation on the ram.

JAMES STEWART RO'II-IERY.

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