US1321456A - Vania - Google Patents

Description

1. C. KOPF.

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afentd Nov. 1919.

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LIFTING JACK.

APPLlcAnoN msn MMI. 22. Isls.

Y -Patentd Nov. 1l, 1919.

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UNITED STATES PATENT OFFICE.

JOHN C. KOPF, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOB TO THE DUFF MANUFAC- TUBING' COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYL- VAN IA.

LIFTING-JACK.

To all 'whom z't ma concer/n:

Be it known t at I, JOHN C. Korr of Pittsburgh, Allegheny county, Pennsy vania, have invented a new and useful Imrovement in Lifting-Jacks, of which the ollowing is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification, in which- F1 re 1 is a developed vertical section of a lifting jack embodying my mventlon, the general plane of the section being on the line I-'-I of Fig. 2;

nig 2 is a horizontal section on the irre ar line II-II of Fig. 1;

ig. 3 is a perspective View of the clutchbarrel and its brake band;

Fig. 4 is a detail sectional view showin one of the friction clutch disks and its enga ement with its shaft; and

ig. 5 is a plan view showing one of the co erating friction clutch disks. v

y invention has relation to lifting Jacks and more articularly to screw jacks.

One of tlie ob'ects of m invention is to provide a jack o this type aving means of simple, novel and effective character, whereby the action of the load on the jack 1s caused to automatically lock the jack against lowering movement while the load is being held or lifted. A further object is to provide locking means ofa` this character in which the lockin action is directlyfproportional to the loa on the jack, Vso that such action increases as the load increases.

A still further object is to provide novel and effective means in connection with the locking means, whereby the jack may be ra idly raised and lowered, when desired.

s'xihe nature of my invention will be best understood by reference to the accompanying drawings in which I have shown the preferred embodiment thereof Aand which will now be described, it being premised, however, that various changes can be made in the details of construction and general arrangement of the parts, without d eparting from the spirit and scope of my invention as defined in the appended claims.

In these drawings, the numeral 2 designates the base of the jack having an upwardly projecting cylindrical column 3, 1n

Specification of Letters Patent.

sprin Patented Nov. `11, 1919.

Application led Harel; 22, 1919. Serial No. 284,318.

which is secured the internally threaded nut 4. 5 designates the screw of the jack, which extends through the nut 4 and downwardly in the column 3. Surrounding the column 3 is a lifting shell 6, having secured toits upper end the casing 7, in whichthe operating parts resently to be described are mounted, and w ich carries at its upper end a lifting plate 8 to receive the load. This late is provided with ball bearingsat 9.

xtendm through a suitable bearing 10 in the si e of the casing is an actuatin stub shaft 11, adapted to receive the usua operating lever (not shown). At its inner end, said 4shaft carries the beveled pinion 12, whose teeth mesh with the horlz'ontal beveled gear 13, which is keyed to the upper portion of the screw 5.

As thus far described, the parts are, in general, of well known character and form no part of my present invention except in combination. 14 desi ates a clutch' member havinga saw-toot ed clutch face on its lower side and which is keyed to the screw 5 to rotate therewith and to move vertically thereon. This clutch member is pressed by 15 into engagement with the corres on ln'gly forme clutch face of a. second c utch member 16, which is loosely mounted on the screw 5, just above the thread thereof. The clutch member 16 is formed on its periphery with worm teeth 17, which engage the threads of a worm 18, secured to a horizontal shaft 19 mounted in vsuitable bearings in the casing 7. This shaft 19 is extended through the casing at one end and is vided with ahand crank 20. This shaft 19 is also provided with a multiple disk friction clutc device comprising one set of clutch disks 21, which are engaged with the shaft 19 to rotate therewith, and another set of intercalating disks 22, which are eng ed on their peripheries with a barrel 23. his barrel has a cylindrical outer surface which is surrounded by a friction brake band 24, one end of this band being connected to a fixed pin 25, and the other end to a rod 26, whose end is connected to a lever 27, having a cam or eccentric portion 28, which bears against the casing 7. A spring 29 is arranged to act on the rod 26.

The threads on the screw 5 and also the threads on the worm 18, are of relatively quick pitch, so that said screws will readily rotate under the action of a load on the jack. The operation is as follows:

The screw and the liftin head or plate 8 can be quickly run up to t e load by turning the crank 20 and thereby turning the screw through the action of the worm 18 and worm wheel 16, the clutch faces of the members 14 and 16 engaging to cause Said members to rotate together and thereby turnthe screw. The shaft 11 is then actuated by its lever in the usual manner to further raise the screw and lift the load. During the load-lifting operation, it will be readily seen that the clutch member 14 will turn with reference to the clutch member 16, and said members will act as a safety .device to prevent the load running down.

The ciutch member 16 is prevented from turning during this action because of the fact that it is engaged with the worm 18, and the action of the load causes an end thrust on the worm shaft 19, which forces the disks of the friction clutch into frictional engagement. The extent of the frictional action of this clutch is directly proportional to the load on the screw increasing as the load increases.

When it is desired to lower the load, the lever27 is turned from the osition shown in Fig. 1 to a position in w lich the lower portion of its cam lor eccentric bears on the casing. This permits an endwise movement of the rod 26 and releases the brake band 24. The barrel 23 is now free to turn, and the entire friction clutch device including said barrel now turns with the shaft 19. This releases theresistance acting on the clutch member 16, and the lowering action can then becontrolled by manipulation of the lever 27. Also, the friction clutch device may be left inand the lowering controlled by the crank 20. In this manner, the jacks can be lowered to any desired extent and stopped in the desired position.

The advantages of my invention will be apparent to those familiar with jacks of this type, since it rovides a high-speed jack capable of han lino' large loads with perfect safety, the lodking action against accidental lowering of the load increasing as the load increases. At the same time, the invention provides means whereb the load may be quickly lowered to any esired extent whenever necessary.

The method of construction and Inode of operation is simple, and the partsA thereof are strong and of durable character.

I claim:

l. A liftin jack having a lifting screw, two indepen ent sets of mechanisms connected to the screw whereby it may be raised and lowered, one of said sets of mechanisms including an automatic clutch to prevent the screw from rotating in one direction and to permit free rotation of the screw in the other direction by the other mechanism, said clutch being mounted on the shaft of the screw, and another clutch device for controlling the operation of the first named clutch, substantially' as described.

2. A lifting jack having a lifting screw, means for actuating said screw to raise the load, a two-part clutch, one member of which is mounted to rotate with the screw and the other member of which is loosel f mounted with respect to the screw, a quick pitch worm geared to the first named clutch member and having an endwise movable shaft, manually operated actuating means for said shaft, a brake device ap lied to said shaft, and manually operatec means for controlling said brake device; substantially as described.

3. A lifting jack comprising a lifting screw, means for actuating said screw to raise the load, a clutch device having one member fixed to rotate with the screw and another member mounted loosely with respect to the screw, said last named member having worm teeth thereon, a worm shaft, a worm on said shaft engaging said teeth, means for manually operating said shaft, and a friction brake device comprising friction elements carried by said shaft, and other coperating friction elements carried independently of the shaft, and manually controlled means for effecting the engagement and disengagement lof the two sets of friction braking elements; substantially as described.

4. A lifting jack having a lifting screw, means for actuating said screw to raise the load, a clutch havin one member mounted for rotation with t e screw and another member loosely mounted with respect to the screw, the last named member having worm teeth on its periphery, a worm shaft, a crank for actuating said shaft, Va worm on said shaft and engaging said worm teeth, a barrel or,casing surrounding said shaft, a set of friction members carried by the barrel or casing, a coperatin set of friction members carried by sai shaft, and means whereby the barrel or casing may be held against movement or mav be free to turn with the worm shaft, substantially as described.

5. A lifting jack having a lifting screw, means for actuating said screw to raise the load, a clutch having one mem'ber mounted for rotation with the screw and another member loosely mounted with respect to the screw. the last named member having worm teeth on its periphery, a worm shaft, a crank for actuating said shaft, a worm on said shaft and engaging said worm teeth,

barrel or casing surrounding said shaft, ing a brake band engaging the barrel or a set of friction members carried by the casing and a handle device vfor. applying barrel or cnsin another set of frlcton and releasing the brake band,substa.nt1ally 10 members carrie by the shaft, and means as described.

whereby the barrel or casing may be held In testimony whereof, I have hereunto against movement or may be freed to turn set my hand.

with the Worm shaft, sand means `compris- JOHN C. KOPF.

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