US1397871A - Jack - Google Patents

Description

J. C. KOPF.

JACK. APPLICATION FILED FEB- 18. I921.

1,397,871 Patented Nov. 22,1921.

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JACK.

APPLICATION FILED FEB. 18, 1921.

1,397,871 I Patented Nov. 22, 1921.

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1,397,871 Patentd Nov. 22, 1921.

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JOHN C. KOPF, OF BELLEVUE BOROUGH, PENNSYLVANIA, ASSIGNOR TO THE DUFF MANUFACTURING COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

Specification of Letters Patent.

Patented Nov. 22, 1921.

Application filed February 18, 1921. Serial No. 445,981.

To all whom it may concern Be it known that I, JOHN C. Korr, a citizen of the United States, and resident of the borough of Bellcvue, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Jack, of which the following is a specification.

This invention relates to jacks, and more particularly to track jacks of surfacing jacks. These jacks are used to raise the rails, or the rails and ties, and have customarily been ratchet jacks, having holding and lifting pawls, the pawls engaging either directly with teeth on the jack-bar, or with a circular ratchet geared through a pinion with the bar. The object of this invention is to provide a jack more particularly of this class, though not a ratchet jack in the ordinary sense, having straight lift on the jackbar and consequent efliciency, affording exact adjustment in lifting, having great lever advantage, and being capable of operating satisfactorily at an inclination, and further presenting the important feature of being capable of being dropped instantly and surely in case of an approaching tram. To this end the invention comprises a novel combination possessing all the advantages of the geared ratchet jack, with greater strength, compactness, efficiency, and reliability in lifting and holding, and greater certainty and dispatch in dropplng.

In the accompanying drawings forming a part hereof:

Figure 1 is a side elevation of a jack embodying the invention, the gear case being shown in vertical section with interior parts in elevation;

Fig. 2 is a rear elevation;

Fig. 3 is a vertical section on the line 33 of Fig. 1; and

Fig. 4 is a vertical section on the line l-i of Fig. 1.

The jack has a stand 1, and a jack-bar 2 slidable vertically in the stand and provided along one side with rack-teeth 3. On the lower end of the bar is a tone 4, and at its upper end a head 5.

transverse operating shaft 6 is journaled in bearings in the frame and has fixed thereon av pinion 7 which meshes with the rack-teeth. One end of this shaft projects from the frame, and bears a ratchet wheel or serrated wheel 8, which is driven by a pivoted actuating pawl 9 in an oscillatory lever socket 10 swung on the shaft. The pawl is pressed against the ratchet by a spring plunger 12, which will also hold the pawl out of engagement with the wheel when the pawl is manually thrown to this position in readiness for lowering.

11 another portion of the shaft, within a case 15 formed on the frame, is a worm wheel 16; and meshing with said wheel is a worm 17 on a shaft 18. The latter shaft is journaled at one end in a bearing in the fixed frame and at the other end in a bearing in a bonnet 19 which is screwed into a large opening in the case. The worm and the worm wheel are of steep pitch, so that the worm wheel is capable of rotating the worm under the action of the load. The end-thrust due to the load urges the worm to the right in Fig. 1, and in so doing compacts a suitable number of loose flat friction disks 20, 21 against each other and against a solid abutment on the frame, whereby suflicient friction is produced by any load to hold it against descent. The said disks encircle the portion of the worm-shaft within the bonnet, the disks 20 being keyed to the shaft, and the disks 21 alternating therewith being adapted to be held against rotation, preferably by being anchored to the frame, by having external notches which engage ribs 22 in the bonnet. The abutment is afforded by a plug 23 screwed into the outer end of the bonnet and having an annular rib 24 to sustain the outermost disk. The thrust is transmitted from the worm to the innermost disk by a sleeve 25, serving also as a bearing bushing in the inner end of the bonnet.

Manual means are provided for releasing the holding device. For this purpose a screw 26 is shown passing through a screw threaded opening in the plug 23, in line with the worm-shaft, the end of the screw being adapted to bear upon the end of the shaft within a cavity 27 in the plug through an interposed thrust element 28. A handle 29 on this screw enables it to be readily turned and thereby moved endwise. In this way, a quick movement in one direction is sufiicient to back off the shaft and worm slightly and reduce or remove the friction between the disks so that the loaded jack-bar will drop, driving the gearing idly. Moving the screw in the opposite direction restores the holding device to condition for holding.

, critical moment.

The effort required to cause the jack-bar to drop is thus very slight and there is no possibility of the jack becoming caught at a Gradual lowering can also be effected by proper manipulation of the screw handle.

What I claim as new is: V

1. A jack comprising the combination of a stand, a rack-toothed jack-bar, an operating shaft journaled in the stand bearing a pinion meshing the teeth of the jaclcbar, ratchetlever operating means on the outer end of said shaft, a worm-wheel also on the shaft, a worm meshing with the worm-wheel and adapted to be driven thereby, a frictional holding device applied by the endthrust of said worm, and means for releasing the holding device.

2. A jack comprising the combination of a stand, a rack-toothed jack-bar, an operating shaft journaled in the stand bearing a pinion meshing the teeth of the jack-bar, ratchet-lever operating means on the outer end of said shaft, a wornrwheel also on the shaft, a worm meshing with the wormwheel and adapted to be driven thereby, a frictional holding device applied by the endthrust of said worm, and a manually-operated screw for relieving the pressure on said device.

3. A jack comprising the combination of stand, a rack-toothed jack-bar, an operating shaft journaled in the stand bearing a pinion meshing the teeth of the jaclebar, ratchet-lever operating meanson the outer end of said shaft, a worm-wheel, also on the shaft,a worm meshing with and adapted to be driven by the worm-wheel and having an endwise-movable shaft, a bonnet receiving one end portion of said worm-shaft, a plug in the outer portion of the bonnet, a holding device comprising friction disks in the bonnet at the inner side of the plug,alternately connected to the bonnet and to the shaft, and an axial manually-operated screw in said plug to bear upon the end of the shaft.

, JOHN C. KOPF.

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