US1436588A - Lifting jack - Google Patents

Description

W. H. GRIFFITH. 4

urmm JACK.

I I 7 APPLICATION FILED JULY M1920. v g gg Patented Nov. 2]., 1922..

Patented New. 21, 1922,

WILLIAM H. GRIFFITH, OF WOBTHINGTON, INDIANA.

LIFTINGr JACK.

Application filed July 8, 1920. Serial No. 394,735.

T 0 all whomit may concern Be it known that 1, WILLIAM H. GRIFFITH, a citizen of the United States, residing at Worthington, in the county of Greene and State of Indiana, have invented certain new and useful Improvements in Lifting Jacks, of which the following is a specification.

My invention relates to an improvement in lifting-jacks.

The object of the present invention is to provide a quick-acting lifting-j ack, in which the mechanism may be slid either up or down on the main bar or standard by properly manipulating the hand-lever, or to impart a step by step motion at the desire of the operator, according to the manner in which he controls the hand-lever.

Another object is to provide an improved means for letting the load down again slowly by the manipulation or operation of the hand-lever.

The present invention consists in a pair of runners slidably mounted upon a bar or standard, and a hand-lever soconnected with the two runners that in ordinary operation it will cause the runners to alternately climb and clutch the bar or standard, and by forcing the hand-lever first to one extreme position and then reversing it a predetermined distance, it will cause the release of both runners, and the simultaneous lowering of both upon the bar or standard.

This invention further consists in a bar or standard, a pair of runners slidably mounted thereon and constructed to automatically climb the bar or standard, ahandlever connected with both runners, means connected with one runner and in position to be actuated by the hand-lever to cause one runner to be unclutched from the bar or standard, and means connected with the other runner in position to be actuated by the hand-lever to cause the release of said last-named runner from the bar or standard, whereby both may be simultaneously lowered by the proper manipulation of th hand-lever.

In the accompanying drawings:-

Fig. 1 is a view from one side of the jack; Fig. 2 is a similar view from the opposite side; and

Fig. 3 is an enlarged sectional view through the operative mechanism.

A, represents the main bar or standard,

the upier end of which is provided with a handle 1, and the lower end is removably held in a base or. foot 52 by the pin, belt or key 3, which may be easily removed to take off the base or foot to assemble or remove the operative parts of the lifting-jack, all of which are slidably mounted on the main bar or standard.

The numeral 4 represents the main runner, which is made in the form ofa casting sleeved around. the main bar or standard and capable of sliding up and down thereon. This runner is hollow, and the holder 5 for clainoing the runner to the bar or standard is loosely housed. therein. and is normally held so that it clutches the front and rear edges of the bar or standard A, due to the action of the stiff spiral spring 6 confined between the lower ed e of the holder at a point just in front of the bar or standard and the bottom of the runner, as shown in Fig. 3.

One of the main f atures of my present invention is to absolutely bring the control of this runner under the influence of the hand-lever, either to impart its step by step upward movement in the lifting operation, or in sliding the runner bodily either up or down. The means and mechanism whereby this is accomplished, which constitutes a fulcrumed in a bearing 9 formed for it in the forward end ot the runner 4. The handlever has another smaller stud 10. which en.- ters a bearing 11 in the bell-crank lever 12, which latter is fulcrumed on stud in the forward'end of the lower runner 13.

While the holder 5 within the. main runner might be rocked by hand, as heretofore, provision is made in my present invention for operating and controlling this holder entirely through the hand-lever; and for this purpose the trip 14 is pivoted by means of a pin or rivet 15 in the lower forward end of the main runner preferably just forward of the bearing 9. This trip is approximately L-shaped, and is pivoted at or near its center, so that the inner end extends over the nose 16 at the forward end of the holder 5,

1 neath, and oi" moving the upper end or the.

tially as fares it will go, upon the stud 8 as an axis, it has the effect of swinging tne smaller stud 10 in the arc of a circle therebebell-crank lever 12 forward against the lower end of the trip which depends inimedt ately in its path, thus rocking the latter and causing its inner end to press against the ends of the trip 1%, which causes the rear end of the holder 5 to swing dow' wardiy and carry with it al spring-actuated'dog 17 pivoted thereon. This enters a notch 18 in the rear edge of the runner, thus unclutching the holder 5 from the bar or standard 51, thus releasing the runners and permitting it to move freely up and down.

Just so tar as the dog 17 is in the notch 18, the main runner l is free to move in either direction, or in other words is unclutched from the bar or standard, and when the dog 17 is out oil? the notch 18 he holder 5 automatically assumes aposition to clutch the forward and rear edges of the bar or stand ard, due to the expansive action of the spring 6, which has been held under compression by the holder 5 when locked by the dog 1'? The action of the lower runner 13 is as follows: holder 5 is norms held clutched to the bar or standard by the action of a spring 19 interposed between the root of the runner 13 and the inner end of the bellcrank lever 12; but in order to bring this lower runner 13 under the control of the handlever 7, when the runners are both to be lowered, the upstanding win 20 is cast integral witl'i its upper right-hand edge, and a spring-actuated plunger 21 is slidable in and out through the hole 22 in the lower end of the hand-lever 7, in position to bear and slide back and forth against the outer sur face of the wing when the hand-lever is actuated in the operation of lilting theobject to be raised, during which action the holder 5 and the lower runner 13 alternately clutch the bar or standard. 7

l'lUWCYEiT, is in The upper edge oi the win the form of acam 23, and by raising the hand-lever sufficiently far so that the plunger 21 clears the wing 20 and drops over the up per edge or cam surface 23, and the handlever is then forced slightly downward, has the effect of forcing the wing rearward, thereby suiiiciently tilting the lower runner 13 to hold it released from the bar or standard A. This is the action which takes place when the dog 17 is in the notch 18, and it is desired to simultaneously lower both the. main runner 4i and the lower runner 13. The plunger is returned to its normal position over the surface of the wing by an incline or switch 24, over which it rides as the lever is forced down, and by which the plunger is. brought to the plane of the outer surface of the wing.

In the operation of raising the load, step-,-

by step, and-causing the main runner land the lower runner 3 to become alternately clutched to the bar or standard ii, it is understood that the dog is is released from the notch 18, and the operator holds the handlever in a relatively low position, almost horizonta giving but relatively slight up and down motions. Then when it is desired to hold the upper runner entirely released in the bar or standard A, by simply pre si the hand-lever down as far as it will go, it causes the trip is to tilt the holder until the dog 1'? entersthe notch 18 in the rear e ge of the main runner a. This permits the main runner to more freely upon the bar or standard it, when the holder 5 is thus locked to the runner, the .lC-T'Jef runner remains clutched to the bar standard 1, un the operator desires to lower both runners, when he raises the hand-lever ur 'il the plunger 21 clears the wing and tuAQS the position v the "ting it bacl: andfrocking the lows 13, thereby holding it released also from the bar or standard, which permits both runners to if" EildG to the bottom or until stopped by the operator. p

stud 25 on the inner side the hand lever Z is in position to strike the dog 17 and I release it from the notch 18 on the main run-- ne if desired, this being done by swinging -lever lnward, so that the stud moves incline 26 on the upper end oi the load to be lrrted by the step by step action, due to the alternate clutching oi the main and lower runners upon the bar or stand as has been fully explained.

We accomplish the lifting, it is repeated. th hand-lever is v moved slightl up and down in a on not far horizontal. To again release the parts "he lever ac ie lens: is first pushed lo i as far nl go, which causes the dog to loci-z holder 5 in the main runner, thus releasthe runner from the bar or standard, and

7 ii p i then by lifting the hand-lever until the slides over the top oi the wing,

plunger and then tly reversing it, it immediately slides all 01 the movable parts to the footer base, or as far down on the bar or standard as desired.

I claim:

1. In a lifting-jack, the combination with a bar or standard, of a pair of runners loosely mounted thereon, a hand-lever connected with both runners, and independent means connected with each'runner and actuate d by the hand-lever for releasing the runners from the bar or standard when the hand-lever is properly manipulated.

2. In a lifting-jack, the combination with a bar or standard, of a pair of runners ill) loosely mounted thereon, a hand-lever connected with both runners, and independent means connected with each runner and ac tuated by the hand-lever for alternately releasing the runners from the bar or standard when the hand-lever is properly ma nipulated.

3. In a lifting-jack, the combination with a bar or standard, of a pair of runners loosely mounted thereon, a hand-lever connected with said runners, a holder connected with one runner and having a spring-ac-- tuated dog pivoted thereto, and means comprising a pivoted trip carried by said runner in position to be actuated by the handlever to swing the holder to a position where the dog locks the holder, thereby unclutching the runner from the bar or standard.

at. In a lifting-jack, the combination with a bar or standard and a pair of runners slidably mounted thereon, of a hand-lever connected with both of said runners, a holder housed within one of the runners, and mounted loosely upon the bar or standard, a dog connected with the holder in position to secure the holder unclutched from the bar or standard when in a certain position, and a trip pivotally connected with the runner in position to be actuated by the hand-lever, and when so actuated to engage the holder, and by moving it to unclutch it from the bar or standard.

5. In a lifting-jack, the combination with a bar or standard and a pair of runners slidably mounted thereon, of a hand-lever connected with both of said runners, a holder housed within one of the runners, and mounted loosely upon the bar or standard, a dog connected with the holder in position to secure the holder unclutched from the bar or standard when in a certain position, a trip pivotally connected with the runner in position to be actuated by the hand-lever and when so actuated to engage the holder and by moving it to unclutch it from the bar or standard, said dog having an incline thereon, and a hand-lever provided with a stud in position to engage the incline and release the dog from the runner when desired to permit the holder to reclutch the bar or standard.

6. In a littingjack, the combination with a bar or standard and two runners slidably mounted thereon, of a hand-lever connected with said runners, a spring-actuated plunger slidably connected with the hand-lever, the lower runner having an upstanding wing with a cam switch on one edge, and the outer surface of the wing holding the plunger back in the hand-lever, and the plunger acting to force the wing back and tilt the runner when the plunger engages the cam edge thereof, the switch being in position to return the plunger to its normal position against the outer surface of the wing when the hand-lever is again depressed.

7. In a lifting-jack, the combination with a bar or standard and runners slidably mounted thereon, of a hand-lever pivoted directly to one runner, a bell-orank lever pivoted to the other runner, and also pivotally connected to the hand-lever, the lower runner having an upstanding wing thereon.

and the hand-lever provided with an inwardly-movable plunger, a holder within the main runner for normally clutching the latter to the bar or standard, a trip pivoted to the main runner in the path of the bellcrank lever in position to belrocked by the latter, and also in position to engage the holder to cause the latter to unclutch the runner, a spring-actuated dog pivoted to the holder and adapted to automatically lock the latter in an unclutched position when tilted by the trip, due to the movement of the hand-lever to a certain predetermined position, the other runner having an upstanding wing with a cam edge in position to be engaged by the plunger on the hand-lever when raised to a certain position for causing the lower runner to be rocked in position to cause. its release from the bar or standard, and the handlever having a stud in position to release the dog on the holder from the main runner when desired.

In testimony whereof I affix my signature.

WILLIAM H. GRIFFITH.

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