US542257A

US542257A - Lifting-jack

Info

Publication number: US542257A
Authority: US
Publication date: 1895-07-09
Anticipated expiration: 1912-07-09

Description

A TTOHN E YS.

Patented July 9, 1895l i 6 e e.

LIFTING JACK.

H. HOLAHAN.

(No Model.)

NITED STATES [PATENT OFFICE.

HARVEY HOLAHAN, OF HARVEY, ILLINOIS.

L lFTlNG-JAC K.

SPECIFICATION forming part of Letters Patent No. 542,257, dated July 9, 1895.

Application filed April '7, 1894. Serial No. 506,666. (No model.)

To all whom, it may concern.:

Be it known that I, HARVEY HOLAHAN, of Harvey, in the county of Cook and State of Illinois, have invented a new and useful Improvement in Lifting-Jacks, of which the following is a specification.

My inventionis an improvement in the class of lever lifting-jacks which, while capable of general application, is particularly adapted for use as a car-jack. The features of novelty are the lever and pawl mechanism employed for raising and lowering the rack or ratchet lifting bar, as hereinafter described.

In the accompanying drawings, Figures l and 2 are partly-sectional side views of my jack, showing the position of parts when the rack or liftin g-bar is being raised and lowered, respectively. Fig. 3 is a vertical central section of the jack, further illustrating the relation and operation of parts. Fig. 4 is an edge viewof a portion of thejack. Fig. 5 is a perspective view of the means for adjusting the pawl-spring. Fig. 6 is a central longitudinal view of the lever.

The metal standard A is tubular and provided with a horizontal foot or base A', also with a lateral brace a, all constructed .integrally. 'Ihe lifting rack-bar C, which slides in said standard, has an enlarged head c and a toe c', the latter projecting through a lengthwise slot in the standard when the rack-bar is raised, but adapted to lie iiush in a slot'in the base A when the rack-bar is lowered.

The rack-bar C is raised and lowered and held locked at any elevation by means of two pawls or dogs D E and a lever F. The

rsaid pawls are arranged within'the enlarged V upper portion of standard A, and the lever works through a slot in the same. The lower pawl D is pivoted at its lower end in a recess in the standard, and serves to lock or hold the rack-bar C at any elevation-to which it may be raised. The upper pawl E is pivoted such engagement by sliding in contact with the inwardly-curved inner wall of the standard; but its action is positively controlled, to a certain extent, by means of a round or flat spring G, whose arrangement is as follows: ItsV lower end is attached to alug on the side of the locking-pawl D, and its upper end slides freely between two lugs on the side of the upper or lifting pawl E. At a point intermediate of the two pawls the spring G is connected with a device H bywhich it may be adjusted, as hereinafter described, for the purpose of changing-t'. e., regulating its action on the pawls. The said device H is a slide arranged horizontally in a slot in the standard A, and the spring G passes through a slot in its inner end, and its outer end is connected with a thumb-lever I, by which it is adjusted as required. The said thumb-lever is pivoted to the 'standard A and provided with a pin which is located eccentrically and works in vertical slot in the slide H. The inner end of the lever is curved or rounded, and thus adapted to contact with and act as a cam on -the locking-pawl D, as will be presently explained. The lever is made in two parts F F, whose connection will also be described later;

The operation of the jack, so far as described, is as follows: Supposing the-liftingl rack-bar C to be near its lowest position (Fig. l) and the thumb-lever I thrown down, then the spring G is held vertical by the slide H or parallel to the rack-bar C, and the main or hand lever F F is inclined upward, while both pawls D and E are engaged with the rack-bar C. If now the lever F F be depressed, (see dotted' lines, Fig. 1,) the upper pawl F. will force the rack-bar C upward the distance of the length of one tooth, while the locking-'pawl D slides over a tooth and engages with it. Then, upon raising the lever F F to its former elevated position, the liftingpawl E slides down over a tooth, while the pawl D remains locked with the rack-bar C and holds it stationary. Upon again reciprocating the lever F F the same operatic-n is repeated, with the result of raising the rackbar C the same distance as before, and so the operation goes on until the rack-bar has IOO been raised as high as required. If now it be desired to lower the rack-bar C the thumblever I is reversed or thrown upward, as shown in Fig. 2, whereby the slide H is adjusted or drawn outward and the spring G is retracted or curved backward, it being thus put under tension, so that it tends to throw and hold both pawls out of engagement with the rack-bar; but owing to the pressure of the latter on the locking-pawl D the latter is held engaged with it, while the pawl E is alone held out of engagement with it. Then, upon depressing the main lever F F', the lifting-pawl E slides upward and engages the rack'bar C and raises it slightly, thus allowing the spring G to throw the pawl D back out of engagement with it. As the leverF F' moves upward to its original position, the rack-bar C slides down the distance of one tooth, being supported during such movement on the upper pawl E; but when the lever is thus rising its cam eudfstrikes (Figs. 1 and 3) upon the head of the locking-pawl D and forces it into reengagement with the rack-bar C, so as to hold the latter from further descent until the main lever F F' shall be again depressed. Thus the operation goes on, the pawls being alternately engaged with and disengaged from the rack-bar C until the latter has been lowered to the required extent.

The construction of the main lever is as follows: The handle of the same is fixed in a tapered socket F', whose inner end is pivoted in the concavity of the longer arm of the lever proper F, and the said socket F' is adjustably connected with such concave arm by means of a screw-bolt f' and nutf2. Thebolt f' passes through the socket F', and its threaded end through the concave arm F, and the nut f2 is applied on the upper side of the latter. A spiral spring f3 encircles the bolt j" at a point between the arm and socket.

It will be seen that by adjusting the nut f2 on the screw-holt f the leverproper F may be adjusted with nicety to regulate the action of the locking-pawl D, so that it will be forced to engage the descending rack-bar at the instant required.

The spring G has no function save to hold the socket F and the concave arm of the lever proper F' spaced apart to the extent permitted by the adjustment of the nut f2.

A modification is shown in Fig. 6, the spring-bolt and nut being dispensed with and the required connection between the 1ever proper F and socket F being made by means of a curved and apertured bar, which passes through a slot in the former and is secured by means of a cross-pin. This two-part construction of lever in either form enables it to be conveniently used under a car.

That I claim isl. In a lifting-jack, the combination with the standard, and a rack-bar adapted to slide in the latter, of the pivoted lever, a lifting pawl pivoted to the lever, a locking pawl pivoted to the standard, aspring extending from one pawl to the other, and connected with both on the sides thereof, and a device attached to the standard and holding the spring at a point intermediate of the pawls, as shown and described. p

2. In a lifting-jack, the combination with a hollow standard having, interiorly, an inwardly curved portion at its upper end, of a pivoted lever, a lifting pawl pivoted to the latter, a locking pawl pivoted in the standard, a spring connected with the pawls for actuating them, and means for adjusting the spring for varying its tension and action on the pawls, substantially as shown and described.

3. In a lifting-jack, the combination with the hollow standard having interiorly an inwardly curved upper portion, a lever pivoted in the standard, a lifting pawl pivoted to Said lever, a locking pawl pivoted to the standard, a ribbon spring which is connected with both pawls, a slide attached to the spring and adapted for adjustment horizontally, and means for securing said slide in different adjustments, whereby the spring is held under different tensions as required to act on the pawls, as shown and described.

4. In a lifting-jack, the combination, with the hollow standard having interiorly an inwardly-curved portion at its upper end, a pivoted lever, a lifting pawl pivoted to said lever, a locking pawl pivoted in the standard, a spring which connects said pawls, a horizontal slide connected with the spring, a lever pivoted to the standard and having engagement with the slide, whereby the latter may be adjusted and held locked as required to change the action of the spring on the pawls, as shown and described.

5. In a lifting-jack, the combination with a hollow standard, and rack-bar sliding therein, of a pivoted lever having its inner end constructed to act as a cam, a lifting pawl pivoted to such end of the lever, a locking pawl pivoted in the standard, a spring for throwing the locking pawl out of engagement with the rack-bar, as shown and described, whereby the locking pawl is pushed into reengagement with the rack-bar when the cam end of the lever is thrown down, as shown and described.

6. In a lifting-jack, the combination with a hollow standard and a rack-bar sliding therein, of a locking pawl pivoted in the standard, a lever proper also pivoted in the standard, and having its inner end arranged contiguous to the locking pawl, to adapt it to act as a cam, a handle socket pivoted to said lever proper, and means for adjustably connecting the latter with said socket, substantially as shown and described.

7. In a lifting-jack, the combination with a hollow standard and a rack-bar sliding IOO IIO

therein, of a locking pawl pivoted in the proper and Lhesoeket as shown and described, standard, a lever proper also pivoted in the to operate as specified. standard, and having its inner end arranged contiguous to the locking pawl, to adapt it to HARVEY HOLHAN. 5 act as a cam, handle socket pivoted. to said Witnesses:

lever proper, and the screw bolb,'nut and J. VAN DELL,

spring arranged in connection with the lever J. S. LAZARUS.