US314716A - Lifting-jack - Google Patents

Description

(No Modem V2 Sheets-Sheet l. T. PHARES.

LIFTING JACK.

Patented Mar. 31, 1885.

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(No Mode1,) 2 Sheets-Sheet 2.

T. PHARES.

LIPTING JACK.

No; 314,716.` Patented Mar. s1, 1885.

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THOMAS PHARES, OF EUREKA, CALIFORNIA.

LlFTlNG-JACK.

SPECIFICATION ormingpart of Letters Patent No. 31e-,716, dated March. 31, 1885.

Application filed August 19,1854. (No m' del.)

.T all whom L'mctg/ concern/.f

Be it known that I, IHoMxs Pannes, of Eureka, Humboldt county, State ofCalifornia, have invented an Improved Lifting-J ack; and I hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to certain improvements in that class of implements known as pawls are held out of contact with the bar, as i will be more fully described by reference to th accompanying drawings, in which- Figure lis avertical section ofthe standard,

' showing thepawl block or head with its pawls engaging with the rack-bar, and the frictional clamp drawn back out of contact. a similar section with the pawls disengaged and the frictional device in contact with the rack-bar. Fig. 3 is an enlarged perspective view with `part of the side broken away. Fig. 4 is a fron-t view showing plate for disengaging the pawls.

A is the standard of my jaclr,wliich may be formed of wood or iron, and is provided with a suitable base, as shown. This Istandard is slotted or formed with a deep channel from one side,and the rack-bar B is adapted to move up and down within the channel,which serves as a guide for it. This rack-bar has a plate, O, at the top,upon which the articleto be lifted will rest conveniently, and an anti-friction roller, D, at the lower end moves in contact with the rear of the channel and standard. Another roller, E, is fixed near the top ofthe standard, and fits into a chamber or depression, F, in

the rear part of the rack-bar, so that the lat ter moves easily, and not much of the lifting power is lost by friction. The pawl block or head Gis adapted to receive a lever at its back,

and has a pivot-pin, II, near the center of the side which fronts the rack-bar, and the pawls I and .I are pivotcd or hinged one above and one below this axis, so that when the block is made to oscillate about its axis the pawls alternately act to push the rack-bar upward, one being drawn back for a new hold while the other is forcing the bar upward, thus givingit a nearly contin nous movement to raise the article which rests upon the plate C. When it is desired to lower the plate C with its load, the pawls I and J are disengaged from the rack-bar, and the frietional clamping device is employed to lower the rack-bar steadily. This device consists of the plates or jaws K, which have their front edges adapted to press against the sides of the rackbar. A block or head, L, is perforated at the rear to receive the lover by which it is actuated, and this block hasatongue, M,whicli projects between the side plates, K. Trunnions N, which project from each side of the tongue M, pass through holes in the plates K, so that their ends are flush with the outside faces of the I plates. Fig.2shows A hole, O, is bored eccentrically through the trunnions, and a pin through this and the sides ofthe standard serves as an axis about which the head andtrunnions areturned by the action of the lever. It will bel seen that when this head stands in such a position that the pin or axis is nearest to the rack-bar the holding-jaws K will be drawn back from the bar and will not press upon it at all. When the lever is moved so as to turn the eccentric the jaws iirmly against the sides of the rack-V bar, and thusv hold it in any position by frictional contact, and this may be regulated by a movement of the lever so as toV correspond with the load, and thus lower it steadily after the lifting-pawls have been disengaged.

In order to lift the pawls I and J ont of contact with the teeth of the raclebar, so as to permit the latter to be lowered when desired, I employ a sliding plate, I), which is fitted to slide up and down the front of the rack-bar, between it and the rear portion of the pawlcarrying head G, as shown in Figs.` 3 and 4. This plate has elongated vertical slots at Q,

through which the pawls project so as to engage with the teeth of the rack-bar, and the pawls are pressed forward by springs R, acting against their backs, as shown in dotted 5 lines at Fig. 3. The lower end ofthe plate P "is turned upward at S, and a blocl,T, is fixed so that this turnedup 'end slides over it, and may either be drawn down below its lower end, so that the pawls will pass through slots Io Q and engage with the rack, or it may be moved upward until the part S engages with a notch, (shown at U, Fig. 5,) when the lower ends ofthe slots Q will press pawls backward until they are disengaged from the rack-bar,

y[5 so that it may be lowered at will.

V is a pawl hinged to the upper portion of the head G, so that its point may be raised to engage with a notch, XV, in the lower part of the head L when the weight has been raised 2o to a sufcient height, and if it isdesired again tolower the rack-bar B this pawl V is raised until its point engages notch NV, the head G being pressed downward. Vhen the head G is again lifted by its'lever, the pawl V will also push head L upward, thus rotating eccentric trunnions N, and causing plates K to press against the sides of the rack-bar with sufficient friction to hold it and its load. The sliding plate Pis then moved upward un- 3o til it has disengaged the pawls I and J from the rack-bar, which is thus left supported by the frictional pressure of the plates K. By depressing the lever in the head G this pressure will be relieved to such an extent as to allow the rack-bar to slide down at any desired rateof speed, thus lowering theload again. Having thus described my invention, what I claim as new, and desire to secure by Letters Patent., is-

l. The friction-clarnp consisting of thejaws 4o K. the head L. with its operating-lever, and the trunnions N, turning in holes in the plates or jaws K, andy having ajournal pin or axis eccentric to the circumference, whereby the jaws are forced against the rack-bar by the movenient of the lever, substantially as herein described. Y

2. In a lifting-jack, the standard A, vertica1ly-moving rack-bar B, the pawl-block G, with its lever and pawls I and .I,with the plate 5o P, in combination with the friction-clamp K, L, and N, substantially as and for the purpose herein described. I

3. In a lifting-jack, the oscillating pawlblock with the vpawls I and J engaging the rack-hama frictioirclamp, K, with its eccentric operatinghead L, having a recess or notch at its iowerside, togetherwith an arm or pawl,

V, hinged to the upper part of the block G, so that it may be niade to engage with therecess 50 in the head L, substantially as and for the purpose herein described.

Y 4. In a lifting-jack. the standard with avertically-sliding raclebar, an oscillating head having pawls I and J engaging the rack-bar, together with the sliding plate P, having slots through which the pawls project, and by which they may be thrown out ot' contact with the rack-bar, substantially as herein described.

In witness whereof I have hereunto set my hand. v

THOMAS PHARES.

YWitnesses:

DAVID WrLsoN, CHARLEs H. HENRY.

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