US1556539A

US1556539A - Screw jack

Info

Publication number: US1556539A
Application number: US15094A
Authority: US
Inventors: John F Parker
Original assignee: Individual
Current assignee: Individual
Priority date: 1925-03-12
Filing date: 1925-03-12
Publication date: 1925-10-06
Anticipated expiration: 1942-10-06

Description

J. F. PARKER SCREW JAbK Filed larch 12, 1925 Patented Oct. 6, 1925.

UNITED -QFN BARKER. Q 3931 14332 ssae est- ,e pli ti'qn e wrehl S rial .N 51

. T0 all'whom it may concern:

The principalobject of my invention, is

to produce a simple, efiicient device, not easily disabled or liable to fail when most needed. and on which. may be used to espea a c rcumferential shoulder 6 which bears'on. the top of the base and supports the column.

ci-al advantage in motor vehicle work, yet adaptable to any lifting operation within its capacity.

Another object is. to, procure. a so-called knock-down feature, which enables the user to pack it in a comparatively small space for transportation.

And still another feature which very largely increases itsusefulness is the provision made for increasing its height when rcqnired, thus making it available for use 1n either low or high hung vehicle runn ng gears.

Other objects will be apparent from read} ing the description contained in my SIJGClfi:

cation when taken in connection with the.

annexed drawing, which discloses one embodiment of my invent on and 1H WlllCh like characters of'reference refer to similar parts;

throughout all the different views,

In the drawing Fig, 1 is an elevation, mostly in section,

ofmy jack;

Fig. 2 is aplan view of the base;

Fig. 3 is a plan view of the nut;

Fig. it is a side View of the nut;

Fig. 5 is a fragmentary section of a part ofthe base, taken on line 55, Fig. 2

Fig. 6 is a plan view of the lifting head;

Fig. 7 is a section through the column and screw, taken on line 77, Fig. 1;

Fig. 8 is a section. through the same parts, taken on line 88, Fig. 1;'

Fig. 9 is a side elevation of the lifting head. and. raising block Fig. 10 is a section through the above parts, taken on line 10-10, Fig. 9, and

Fig. 11 is a view, in perspective, of the lower portion of the column.

Referring to the drawings, 1 is the base of the jack, preferably made round at the bottom a d rising in a conical iQ Z Q 9 he 19- An opening 2, on the upper end, receives'the.

column 3 and'is soimade that a locking 'f'ea ture is obtained. By observing 2 it will be seen that this opening is a combination. of two concentric circles of different diameters, the rg of th wo be n Qf such a size as to easily allow the ears 5, of the column t0 pa s the eth ougha aft which by a quarter turnof the column these ears may slip under the overhanging shelves or flanges 5 forming the smalle fof the two.

circles, "and prevent a withdrawal of the column from the base.

Placed above the ears 4, on the column,-is

and any weight put thereon in operating the jack. To more fully lock the column to. the base,,and prevent its turning thereon, I provide on the column the earsl7, and pivotally mount'betweenthem the pawl 8 which may lodge, when in locked position, in the recess.

9 formed in the side of the base, near the top. The column is therefore held against.

rotation on. the base by the pawl 8, and against withdrawal from thesame by the ears 4:. i 011 h t f the 01 11 11 i a lange outwardly disposed, andturning on which is a, member 11',, havinga two-fold function.

. on the larger of the two shoulders 17,.isa

collar 18, having ears 19 extending upwardly and between which is pivoted, on the pin 20, the pawl 21. To hold the collar (18) in position, vertically, a second collar, 22, fitting the smaller of the two shoulders 23,. is fixed on the member 11 by the screws 21-.

n the e re 'upper end o the screw nd'fiXd t rned .dTQ pcrticn, thereof, is the lifting head 25'. 'As will'be seen in Figs. 1 and 10 the top surface of this head is slightly concave, but at one side it rises, as at 25, to a considerable distance above the central portion. This serves as a lateral stop for the jack as it is slid under the axle housing, or other jack contacting point, of the vehicle. i

An extended portion, 27, of the pawl 21, has a tapped hole 28 therein which provides means for inserting a handle 29 with which to actuate the nut.

To key the screw 14: to the column 3 and thus prevent it from rotating with the nut 13, when the latter is rotated in the process of operating the jack, I cut, or core, keyways 30, extending from the bottom of the column to the flange on the top of the same. These key-ways engage each end of a pin, 31, extending through the screw 14 at a spaced distance from the bottom end thereof.

The height of my jack, using the plain lifting head, is admirably adapted for use under the lower hung vehicles. It is often necessary to operate it under those having their running gear a considerably greater distance from the ground. To meet this contingency I provide at raising block 32 which may be a temporarily fixed part of the lifting head, or as I preferably construct it, a quick detachable element. The bottom of the block closely fits the top surface of the lifting head and to more surely hold it in place, while in use on the head, I provide depending wings 33, filling depressions 34; made in the sides of the lifting head 25.

In operation, the jack is placed under any part of the vehicle under which it is proper to lift,the screw having previously been raised so that the lifting head lightly contacts with the lifting point. Assuming that the: screw is cut with a right hand pitch thread, as shown, (although either right or left hand threads .may be employed) then a movement of the hand lever 29 to the left will start the screw upwardly. After making a convenient movement to the left, the lever is lifted (see dot and dash lines, Fig. 1) an amount-sufficient for the pawl 21 to clear the teeth 12 and a reverse movement to the right is made. The lever is then dropped,allowing the pawl to seat in one of the tooth spaces and the operation of oscillating the lever backwardly and forwardly is continued until the proper and desired lift has been made. I

In heavy lifting it would be advantageous to construct the screw using a single pitch thread. 011 lighter work, and where time is a more valuable consideration than power, 1 may elect to make this thread either double or triple.

To reduce the lifting movement of the hand lever when reversing, I bevel the tops of the teeth 12,tapering them toward the top.

It will be observed, by examining Figs. 2 and 8, that the column 3 may be inserted in the base in two ways. The locking parts being double, or two in number, and symmetrical, the column may be inserted in the base, then taken out and turned 180 degrees and reinserted. In either case it is entered, turned to the right until it brings up on the stop 35 located beneath and at the end of the overhanging flanges 5, and the locking pawl 8 dropped into place.

In the description and illustrations of my device I have presented one embodiment of my invention. I shall feel at liberty to depart from the exact mechanical construction as herein set forth, in cases where I deem it expedient, provided, however, that all such changes shall not be in conflict with the meaning and intent of the invention and shall fall within the scope of the appended claim.

What I claim is:

In a screw jack, the combination, with a tubular body member having a nut rotatably mounted thereon and a screw adapted to engage said nut and to operate within and above said body member, and with means to actuate said nut, of a base member having an aperture in the top thereof through which the lower portion of said body member may pass, a circumferential flange on said body member adapted to bear on the top of said base member, a flange on the top of said base member projecting inwardly and with portions in opposition cut away for a spaced distance, lugs on said body member beneath and separated a spaced distance from said circumferential flange and adapted to enter the spaces where said base member flange is cut away, and positioned, vertically, so as to engage the under sides of said base flange when said body member is oscillated a pre determined distance on said base member, whereby the said base member flange may serve as the tongue and the space: between the lugs and the circumferential flange of the body member may serve as the groove, and together, constituting vertical locking means for the two members, stops on said base member against which said lugs may abut, restricting the lateral movement of said body member, a pawl pivotally mounted on said body member and adapted to engage a depression on the said base member and constituting lateral locking means for said body member on said base member, sul stantially as described.

JOHN F. PARKER,