US1279182A - Lifting-jack. - Google Patents

Description

H. W. TRUE.

LIFTING JACK.

APPLICATION man MAR. 5. 1914.

Patented Sept. 17, 1918.

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HENRY W. TRUE, OF ARLINGTON, MASSACHUSETTS.

Specification of Letters Patent.

LIFrme-JAcK.

Pate ted Sept. 17, 1918.

Application filed March 5, 1914. Serial No. 822,544.

To all whom it may concern:

'Be it known that I, HENRY W. TRUE, a citizen of the United States, ,and a resident of Arlington, county of Middlesex, and State of Massachusetts, have invented an Improvement in Lifting-Jacks, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like arts.

This inventlon relates to lifting jacks, and more especially, though not exclusively, to a jack for lifting the axle of a vehicle.

My invention will be best understood by reference to the following specification, when taken in connection with the accomp'anyin drawings of one specific embodiment t ereof,-whi-le its scope will be more particularly pointed out in the appended claims.

In the drawings:

Figure 1 is a side elevation of-a lifting jack embodying my invention;

Fig.2 is an enlarged detail sectional view on line 22 of Fig. 1 ;and

Fig. 3 is an enlarged central vertical sectional view of the jack viewed from the same direction as Fig. 1. Referring to the drawings, and to the embodiment of my invention which I have selected for illustration, I have there shown a lifting jack having a base 4, provided with one or more traction wheels 5, herein mounted on a shaft 6, and preferably so "disposed that the bottomface of the base is tangent to the periphery or peripheries of the wheel or wheels. A standard 7, rising from the base at one side of the wheel or wheels; supports a lifting mechanism, designated generally by the numeral 8.

Any other appropriate lifting mechanism may .be provided, but herein the lifting mechanism comprises a slide 9, mounted to a slide vertically upon the standard 7, a lifting lever 10 'fulcrumed at 11 on the slide,

.a load-supporting and lifting member 12, to

which the lifting lever is pivoted, anda link or pain of links 13. pivoted to the slide and to the lifting member, and so arranged as to swing parallel to the liftin lever. It will be seen that the slide 9, in ependentlyof its movement on the standard 7 serves as an upright supporting element for the member 12. The load-supporting anism bodily to effect its nitial ad ustment to-the load, I havexherein provided with an upwardly projecting lug 14 to sustain the load, but-if desired, there may be provided an additional support, herein comprising a vertically adjustable post 15, herein provided with' a rest 16 swiveled thereon. This rest may be, and preferably is, offset somewhat, as shown, to enable it 'to be placed beneath the rear axles of a vehicle without interferin with the truss rod that is vervoften use on axles, and without interfei ing with obstructions sometimes met with in lifting "other objects. The post 15 may be otherwise appropriately secured in the desired position of adjustment, but herein is provided with a series of teeth 17 constituting a straight ratchet or rackcooperating wlth a pawl 18 provided with an appropriate spring 19, by means of whichv it is held in engagement mounted, but is herein pivoted on a pin 21,

constituting the pivotal connection between the l1 ft1ng lever 10 and the load-supporting andllftin drawn in an upward directlon, it is herein provided wlth a: laterally inclinedrecess 22, to receive a sprlng-pressed pin 23, which will member 12. As a means for preven'tmg t e post from bein entirely with-v automatically Withdraw from the recess.

when the post is dropped" down.

' As a means for raising, the lifting mechpreliminary or provided ,a foot-treadle 24, fulcrumed at 25 on the base, and connected in any appropr1ate manner to theslide, so that the latter may be raisedwitli the lifting mechanism Y thereon by simply depressing the rear end .of the foot-treadleby means of the foot. The treadle may be otherwise appropriately connected to the .slide to lift thelatter, but

herein the lever is provided with a slot 26,

to receive a pin 27 carried by the slide. The slide, when thus raised, may beheld in the desired position of adjustment by any other appropriate means, but here n the standard is providedwith a plurality of teeth 28, constituting a straight ratchet or rack engaged by the pawl 29. This pawl may be other-' ..wise appropriately mounted, but is herein pivoted on a in 30,4c0nstituting thepivotal connection 0 the links '13 with the slide 1 with the: ratchet. This pawl may be, and

its wheels, it isherein provided with means- .whereby the liftinglever 10 may be utilized 'The pawl may be urged toward its rack by releasing the pawl 33, as hereinafter "ex plained, and simply depressing the grasping*portion of the lifting lever, thus raising the load-supporting and lifting member 12. The latter maybe secured in the desired position of adjustment by any other appropriate means, but herein the slide-is provided with a series of teeth, or rather two series of teeth, 32, constituting a ratchet or rack, 'which may be engaged by a pawl 33- carried by the load-supporting and lifting member. In order that the pawl may be readily engaged with and disengaged from its ratchet, it is herein mounted on apivot 34 above the pivotal connection of the links 13 with the lifting member, and preferably intermediate the pivotal connections of the links and lifting lever with the lifting member. By this disposition of the pawl, its length and the location of its pivot are such that the weight suspended by the pawldoes not tend to cause it to cramp. The pawl is herein interposed between one of the links 13 and the adjacent side of the lifting member 12,-

and is provided with a segmental slot 35 to receive a pin 36 constituting the pivotal connection of the links to the lifting member.

.As a means for facilitating the movement of the jack about from place to place upon to fulcrum or tilt the jack upon its wheel or wheels, to allow it to be wheeled along the floor. This may be accomplished by any other suitable means, but herein the slide 9 is provided with a tooth 37 consti-" tuting a stop which is normally engaged by a a shoulder 38 on the pawl 33, wherebythe latter" in its normal position locks the lifting member 12 against upward movement,

and consequently locks the grasping portion of the lifting lever against downward movement. J

It must now be evident that, since the parts, are thus locked, downward pressure upon the graspingportions of the lifting lever must result in the jack being tilted bodily upon its wheelsars a fulcrum, and it' can. then conveniently be j trundled about from-one point to -another.

Thejpawl 33 may be operated by any other appropriate means, but'herein is provided with a pin or stud 39.,'to which one end of v a link de'signated'generally by the numeral 40 is pivoted; The other end of this link is herein pivoted at 41 to a manually operablelever 42 fulcrumed at 43 on the lifting lever 10. As a means for holding the pawl 33 inengagement with the tooth 37, or the teeth 32 as the case may be, I have herein provided a helical spring 44 encircling the link 40 hearing at one end against a collar 45 secured to the link, and at its other end to an abutment 46 secured to the lifting lever 10. The link 40 may be non-extensible if desired, but is herein made wieldingly eX- a shoulder or-collar 50 on the rod, and at its other end against a shoulder 51 in the guide.

This spring in practice is made relatively larger and heavier than the spring 44, and

normally holds the end of the rod 47 seated with firm pressure against an abutment 52 within the guide. The strength of this spring is such that when the manually operable lever 42 is operated, it will overcome the tension of the spring 44. When the pawl 33 is engaged with the tooth 37, as shown in the drawings, it may be disengaged therefrom by simply depressing the hand lever 42, thus causing the link 40- to rock the pawl on its pivot and withdraw, it from its locking engagement. During this movement, the link will of course act precisely as if it were non-extensible,that is to say, a solidrod from end to end.

Assuming now that the lifting lever 10 hasbeen depressed, and that the lifting mechanism is sustaining a load, it must be apparent that the downward force exerted by the pawl 33 upon the tooth of the ratchet 32 is very great. Under such circumstances, then, it is found necessary in practice I to relieve the weight somewhat before attempting to withdraw the'pawl from such engagement. This may be accomplished very readily by placing one hand upon the grasping portion of the lifting lever, and the other hand upon the hand lever 42, and exerting a downward force upon both. The first.result will be that since the load is on the pawl, the latter cannot be withdrawn at once, and hence the spring 49 will be placed under tension; that is to say, power will be stored up in said spring so that when, upon the applicationof further pressure, the load upon. the pawl is relieved, the stored up power will at once become effective automatically to withdraw the-pawli-.;fromits locking engagement with the ratchet, without any thought or attention on the part of the operator,

As a means'for preventing the swinging motion of the lifting lever from accidentally withdrawingfthe pawl 33 from its engagement with its ratchet, the pin 39 is herein placed approximately in line with and adjacent the axis of the pin 21. When thus arranged, the pawl is substantially unalfected by the swinging movement of the lifting lever, though not fulcrumed upon the pin 21. While I have herein shown and described one specific embodiment of my invention for illustrative purposes, and have disclosed and discussed in detail the construction and arrangement incidental to one specific application thereof, it is to be understood that the invention is limited neither to the mere details or relative arrangement of parts, nor to its specific application herein shown, but that extensive deviations from the illustrated form or embodiment of the invention may be made; without departing from the principles thereof.

. Having thus described my invention, what I claim and desire by Letters Patent to procure is:

1. A lifting jack comprising, in combination, a base, a traction wheel or wheels mounted on said base, a load-supporting member carried by said base, a lifting lever connected to said load-supporting member, a ratchet, a, pawl carried by said load-supporting member and coiiperating with said ratchet to locksaid load-supporting member against downward movement, and means engaging said pawl to lock said load-supporting member againstupward movement.

2. A lifting jack comprising, in combination, a base, a traction wheel on wheels mounted on said base, a standard rising from said base, a slide mounted to move vertically upon said standard, a load-supporting member supported on and mounted to, move vertically relatively to said slide, a lifting lever fulcrumed on said slide and connected to said load-supporting member, a ratchet on said slide, a pawl carried by said loadsupporting member to lock said load-supporting "member against downward movement, and a stop on saidslide to engage said pawl and lock said load supporting member against upward movement.

3. A lifting jack comprising, in combination, a base, a traction wheel 01' wheels mounted on said base, a standard rising from said base at one side of said wheel or wheels, a slide mounted to move vertically on said standard, a lifting lever fulcrumed on said slide and having a grasping portion extending laterally from said standard inthe direction of and beyond said wheels, and means to lock said lever in an upward position.

4. A lifting jack comprising, in combination, a base, a standard rising from said base, a lifting mechanism mounted to move vertically on said standard and including a lifting lever extending laterally, and a foot treadle fulcrumed on said base and connected to said lifting mechanism to lift the same bodily with relation to said standard, said foot treadle extending in the same general direction as said lever.

5. -A jack comprising, in combination, a base, a Wheel carried thereby, an upright element having a rack thereon, a lifting member associated with said upright element, a pawl cooperating with said rack comprising plates pivoted to the sides of said member, a web between said plates, a lug on the upright element to engage the web and a lever for moving said lifting member.

6. A jack comprising, in combination, a base, a wheel carried thereby, an upright element having parallel vertical racks, a lifting member between said racks, links connecting said member and uprightelement, a handle for operating the member, a pawl comprising plates pivoted to said member and coiiperating with the racks respectively, a web between the plates and a lug on the upright element to enga e the web.

In testimony whereo I have signed my name to this specification in the presence of two subscribing witnesses.

HENRY W. TRUE.

Witnesses:

ROBER E. KAMMLER, ARTHURE. CARSON.

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