US3786692A

US3786692A - Hydraulic garage jack

Info

Publication number: US3786692A
Application number: US00241548A
Authority: US
Inventors: B Bjork
Original assignee: DOMKRAFT NIKE AB
Current assignee: DOMKRAFT NIKE AB
Priority date: 1972-04-06
Filing date: 1972-04-06
Publication date: 1974-01-22
Anticipated expiration: 1991-01-22

Abstract

A garage jack, the load is lowered by depressing a pedal at the end of a pedal arm. To prevent the load from being lowered by unintentional depression of the pedal, the pedal arm is divided into an outer portion connected with the pedal proper, and an inner portion. The portions are adapted to be disengaged from each other such that in disengaged position the pedal cannot effect lowering of the load.

Description

United States Patent [191 B'o'rk Jan. 22 1974 [54] HYDRAULIC GARAGE JACK Primary ExaminerCharles J. Myhre 75 I t B A d B k E kl t men or 3:52 ers s una Assistant Exam1ner-Frank H. McKenzie, Jr.

Attorney, Agent, or FirmE1liott I. Pollock et a1. [73] Assignee: Domkraft AB Nike, Eskilstuna,

Sweden 22 Filed: I Apr. 6, 1972 ABSTRACT 1 PP Nod 241,548 A garage jack, the load is lowered by depressing a pedal at the end of a pedal arm. To prevent the load 52 us. or 74/5 12, 74/469, 74/524 from being lowered by unintentional depression of the [51] Int. Cl G05g 1/14 P the Pedhll arm is divided into an outer portion 581 Field of Search 74/524, 519, 512, 491; connected with the Pedal Proper, and an Inner P 254/2 R 8 R, 8 B, 8 C tion. The portions are adapted to be disengaged from each other such that in disengaged position the pedal [56] References Cited cannot effect lowering of the load.

5 Claims, 5 Drawing Figures MENTEUJAN 22 H?" SHEET 2 BF 3 HYDRAULIC GARAGE JACK BACKGROUND OF THE INVENTION This invention relates to a hydraulic garage jack of the kind comprising a control means to actuate means for lowering the lifting means of the jack.

When one is working underneath a vehicle, which is held in lifted position by the lifting means of the jack, it may happen that the release pedal-of such a jack is depressed unintentionally. The resulting lowering of the vehicle involves the risk of severe accidents.

SUMMARY OF THE INVENTION Such accidents are prevented by a safety device on the jack accordingto the present invention, which is characterized in that it comprises means to render the lowering means of the jack by the control means at least when the control means is actuated in the same way as for lowering the lifting means. Thus, when a mechanic is working below the vehicle, the release pedal can be entirely disengaged from the-release valve. When the load is to belowered, the pedal can be actuated only by an intentional manipulation. The pedal can be engaged only by a double movement, viz. by being lifted upwards and pushed inwards by hand or foot. In disengaged position, the pedal cannot be engaged by unintentional horizontal forces, for example from a tool or other objects possibly striking against the jack in operation.

BRIEF DESCRIPTION OF THE DRAWINGS One embodiment of the invention is described in the following, with reference to the accompanying drawing, in which FIG. 1 by a lateral view shows the rear end of the jack 'with disengaged release pedal,

FIG. 1A in greater detail shows the coupling of the release pedal when the pedal is in engaged position,

FIG. 2 shows a view from above of the device according to FIG.- 1,

' FIG. 3 shows an alternative coupling means for the release pedal when the pedal is disengaged, and

FIG. 3A shows the device according to FIG. 3 when the pedal is engaged.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The jack is movable on wheels 1 below the object to be lifted. The lifting means proper is located at the front end (not shown) of the jack. For elevating the lifting means, a pump handle 2 is provided at the rear end of the jack where it is rotatably supported about a shaft 3. Upon lifting and lowering the handle, a piston in a pump cylinder 4 is reciprocated and causes a pressure fluid to elevate the lifting means.

For lowering the lifting means, a control arm is provided, which comprises a pedal portion 5 coupled together with an inner arm portion 6. The coupling includes a horizontal axle journal 7 extending transversely through the inner arm portion 6. At said journal 7 the inner arm portion 6 is surrounded by a pair of legs 8 in a fork-like manner, which legs constitute the inner end of the pedal portion 5. Each of said legs is provided with an elongated hole 9 by means of which the pedal portion 5 is supported on the axle journal 7, and which holes permit movement of the pedal portion between two positions in its longitudinal direction relative to the inner arm portion 6. I

The outer end of the inner arm portion 6 includes an upwardly projecting edge 10 adapted to engage with a corresponding recess 11 in the lower surface of that part of the pedal portion 5 which connects the legs 8. In FIG. 1A the edge 10 and recess 11 are shown engaged with each other. The pedal portion 5 is then in inserted position. Upon depression of the pedal portion 5 the inner arm portion 6 is then moved along with the movement of the pedal portion 5. Uponlifting of the pedal portion 5, however, it can turn about the axle journal 7 without also moving the inner arm portion 6. Due to the inclination of the edge 10, the pedal portion 5 by itself cannot slide out of the engagement with the edge 10 when the coupling position is as shown in FIG. 1A.

The pedal portion 5 is disengageable from the inner arm portion 6. For its disengagement, the pedal portion is pulled out in its longitudinal direction, whereby the condition shown in FIG. 1 is obtained. The edge 10 has been disengaged from the recess II. The pedal portion 5 now rests with an edge 12 against the pump cylinder 4. Any unintentional lowering of the lifting means is prevented effectively, because upon depression of the pedal portion the inner arm portion 6, due to the edge 12 becoming a fulcrum, is actuated by a lifting rather than a lowering force from the axle journal 7. In the alternative coupling arrangement according to FIG. 3, the edge 10 and recess 11 with respect to their function are replaced by an L-shaped groove 9A in each of the legs 8. Consequently, the coacting

stop surfaces

10A and 11A can be given plane shape.

The inner arm portion 6 is supported rotatably about a shaft 13 in the jack. Upon raising of the inner end of the inner arm portion 6, the release valve, which is located in a housing 14, is actuated in that a valve element 15 is permitted to raise, and the lifting means is lowered. The element 15 normally is held depressed, and thereby the release valve non-operative, by means of a compression spring 16, which tends to turn the arm portion 6 clockwise and thereby holds the inner end of the arm portion pressed against said element 15. The spring 16 in FIG. 1A also holds the pedal portion 5 in upper position, and it is against the action of spring 16 that the pedal portion 5 is depressed when the jack is to be released.

With the jack shown in the drawings, the pedal portion 5 (see FIG. 2) serves as the only carrying handle when the jack is transported by carrying it. The pedal portion 5, therefore, normally is disengaged from the arm portion 6 when the arm portion is placed below the vehicle. 1

What I claim is: 1. A hydraulically operated garage jack comprising in combination,

means for hydraulically raising a lifting means, release means for at times actuating said first named means to lower said lifting means, and a release pedal operatively connected to said release means for actuating said release means, said release pedal being manually operable between a first position in which said release pedal is ineffective to actuate said release means and a second position in which said release pedal is effective to actuate said release means.

2. The jack of claim 1 in which said release means comprises a pivotally mounted inner arm member and a release valve actuated in response to the pivoting of said inner arm member, said release pedal in its second position engaging said inner arm member to permit actuation of said valve in response to actuation of said release pedal.

3. The jack of claim 2 wherein said release pedal comprises a U-shaped end portion whose legs are pivotally supported on a free end of said inner arm member, the pivoted support for said release pedal on said inner arm member comprising an axle and a cooperating elongated aperture permittng longitudinal movement of said release pedal relative to the pivot, said release pedal having the bight portion of its U-shaped end en- 'portion which bears against said inner arm member to effect rotation thereof about its pivot only when said release pedal has been moved to one end of its permissible longitudinal motion.

(5/03) "1 1 r 1 w 'fi r 1' CERTH lQA I In 01* (,ORRhC i EON Patent No. 3,786,692 Dated January 22, 1974 Inventor(s) BENGT ANDERS BJORK It is certifieu chat error appears in the abAe-identified patent and that said Letters Patent are hereby corrected as shown below:

Foreign Application Priority Data April 6, 1971 Sweden, .4472/71 Signed and sealed this 23rd dag, of April 1971 .0

( SEAL) Attest:

'BDE'JAI- D I-IJ-LETCEmlLJR, G. MARSHALL DAMN Attosting Officer Commissionor of Patents

Claims

1. A hydraulically operated garage jack comprising in combination, means for hydraulically raising a lifting means, release means for at times actuating said first named means to lower said lifting means, and a release pedal operatively connected to said release means for actuating said release means, said release pedal being manually operable between a first position in which said release pedal is ineffective to actuate said release means and a second position in which said release pedal is effective to actuate said release means.

3. The jack of claim 2 wherein said release pedal comprises a U-shaped end portion whose legs are pivotally supported on a free end of said inner arm member, the pivoted support for said release pedal on said inner arm member comprising an axle and a cooperating elongated aperture permittng longitudinal movement of said release pedal relative to the pivot, said release pedal having the bight portion of its U-shaped end engaging with a cooperating part of said inner arm member only when said pedal release mEmber has been moved longitudinally toward one end of its permitted motion relative to its pivot on said inner arm member.

4. The jack of claim 1 wherein said release pedal is pivotally supported on said inner arm member.

5. The jack of claim 4 wherein said release pedal is slidable longitudinally relative to its pivotal support on said inner arm member, said release pedal including a portion which bears against said inner arm member to effect rotation thereof about its pivot only when said release pedal has been moved to one end of its permissible longitudinal motion.