US3013772A - Quickly extendable mechanical jack - Google Patents

Description

Dec. 19, 1961 N. F. ATHERTON EI'AL 3,013,772

QUICKLY EXTENDABLE MECHANICAL JACK Filed Sept. 22, 1958 6 IN VEN TORS N94 F HTHEZTON Pan/04o Mxi'esjoav A T' TOEIVE'VS United States Patent 3,013,772 QUICKLY EXTENDABLE MECHANICAL JACK Neii F. Atherton, Bayside, and Donald W. Sessody, Milwaukee, Wis., assignors to Applied Power Industries, Inc., a corporation of Wisconsin Filed Sept. 22, 1958, Ser. No. 762,546 3 Claims. (Cl. 254-99) The present invention relates to mechanical lifting jacks.

Devices of this nature usually employ a threaded rod which is rotated to cause a load-engaging saddle or the like to be moved relative to the rest of the jack. This type of screw adjustment is desirable because of the good leverage advantage and also because of the smooth movement characteristic. However, it is often necessary to first move this saddle a considerable distance on the jack before it contacts the load. This preliminary positioning of the lifting member to a point where it can commence the lifting operation is time-consuming aswell as being objectionable from a standpoint of requiring considerable effort on the part of the operator.

The present invention provides a mechanical lifting jack having a separate saddle carrying assembly which is quickly adjustable relative to the rest of the jack so as to quickly position the saddle closely adjacent the load to be moved. Upon reaching this position, the saddle is then moved by a screw adjustment to move the load.

More specifically, the present invention provides a jack of the above type in which the saddle-carrying assembly is telescopingly engaged with the jack base assembly so as to provide a compact and neat-appearing jack and one which is particularly strong, rigid and efiicient in performing its intended functions.

The arrangement of the-improved jack is such that the means for effecting the fast initial movement of the loadengaging member is so located as to be accessible regardless of the position of the load and is operable without the necessity for any tools and without danger of the operator hurting his hands.

Generally, the invention provides an improved mechanical lifting jack of the screw type in which means are provided for rapidly moving the load-carrying member through an initial distance of travel to a position adjacent the load to be moved.

These and other objects and advantages will appear hereinafter as this disclosure progresses, reference being bad to the accompanying drawings, in which:

FIGURE 1 is a side elevational view of a mechanical jack which incorporates the present invention, certain parts being in section or broken away for clarity;

FIGURE 2 is a perspective view of the jack shown in FIGURE 1;

FIGURE 3 is a sectional view taken on line 3-3 of FIGURE 1, but on an enlarged scale;

FIGURE 4 is an enlarged sectional view taken on line 4-4 of FIGURE 3;

FIGURE 5 is a fragmentary enlarged view, partially in section, of the upper end of the telescoping member of the saddle-carrying assembly;

FIGURE 6 is atop view of the showing of FIGURE 5;

FIGURE 7 is an enlarged fragmentary cross-sectional view of the upper end of the jack showing the manner in which the screw is supported on the upper end of the main strut; and

FIGURE 8 is an enlarged, fragmentary sectional view of the saddle nut and washer.

Referring in greater detail to the drawings, the jack chosen for purposes of illustrating the invention is of the bipod type which includes a main leg or strut 10 and a secondary leg 11 pivoted thereto by a pin 12. A wire hairpin type leg clamp 13 is pivotally connected at its and partially ICC open end to the lower end of strut 10.and its closed end 14 embraces leg 11 to hold the legs apart and in a supporting position. The lower ends of the legs 10, 11 have base plates 15, 16, respectively, which are fabricated from sheet steel and are welded thereto. These plates form relatively wide supporting feet for the jack which enhance its stability.

The main strut 10 is of channel shape and has a slot 17 extending along its length on the front side and also has a series of spaced apertures 18 along its rear side. This strut is fabricated, for example, from a draw quality strip steel of about number 9 gage, and forms one of the telescopic members of the jack.

Slidably mounted within the main strut and quickly adjustable relative thereto in any one of a series of positions, is the load-supporting assembly 20. This assembly includes a channel 21 which is generally square in crosssection and is slidably mounted in the main strut 10 and thus forms the other telescopic member of the jack.

' Means are provided between these two telescoping channels 10 and 21 for securely holding them in any selected position relative to one another. This means takes the form of a lock pin 22 which is shiftablymounted in the lower end of channel'Zl and is engageable in any one of the apertures 18. The lock pin includes a relatively large hook portion 23 which extends through slot 17 and by which the operator can grasp the-pin by his fingers to pull it against the bias of a spring 24 and out of engagement with the aperture in which it may be positioned. The lock pin 22 and its encircling spring 24 are mounted in a sleeve 25 which is welded as at 26 and 27 to the inside of channel 21. The pin is also comprised of an enlarged end 28 which is threaded on one end of an extension of the hook 23. It will be noted that the spring 24 seats at one end on an internal shoulder 29 in the sleeve 25 and at the other end against pin 28.

To assemble this locking means so as to prevent its accidental disassembly, the sleeve is first welded to the interior of channel 21. The hook is then inserted in the sleeve and the spring then slipped into the sleeve and around the extending hook portion. The pin portion 28 is then threaded on the threaded hook extension and the end of the latter is then swaged to prevent removal of the pin. The interior of the sleeve is preferably lubricated with a lightweight grease.

The top of the inner channel 21 is formed, as best shown in FIGURES 5 and 6, into a generally circular shape so as to snugly receive the circular cover 30. Prongs 31 are formed on this top end of the channel, which prongs are adapted to extend into the corresponding holes 32 (FIG. 7) in the cover 30.

An axial thrust bearing 33 is mounted on the cover 30 and this bearing supports the load through the collar 34 as follows.

A long threaded shaft 35 forms a rotatable screw and is located within the inner telescoping member 21 and its upper end extends through the cover 30, bearing 33 and collar 34. A handle 36 extends through aligned apertures in the collar 34 and screw 35 to thereby lock them together. The handle is held captive in the collar by any suitable means such as the snap ring 37, and rotation of the handle causes the screw to rotate therewith. The weight on the screw shaft 35, as will more fully appear, is transmitted by the anti-friction bearing 33 through the inner channel 21 to the main strut 10.

A load-engaging member in the form of a saddle 40 is operatively connected with the screw 35 so as to' be moved by rotation of the latter, as follows.

The saddle is fabricated of sheet steel and includes spaced guide portions 41 and 42 which extend around the screw and between which is positioned a saddle nut 43 threadably engaged on the screw. The upper end of the saddle nut is formed on a generally spherical radius which mates with a complementary surface of a washer 44. Washer 44 is located between the nut 43 and portion 41 of the saddle and transmits force, as the screw is rotated, from the traveling nut to the saddle to cause the latter to move with the nut.

Assume the load L to be raised is located near the upper portion of the jack base assembly as indicated by the phantom lines and the saddle happened to be in the lower position indicated by dotted lines. Rather than turn handle 36 until the saddle reached the load, the operator simply pulls the hook 23 to disengage the lock pin from its aperture and the saddle is then manually lifted to a position directly under the load where the lock pin is then allowed to engage the nearest available aperture 18. This initial movement is accomplished very rapidly and it will be noted that the lock pin is accessible to be grasped by the operator regardless of the position of the saddle.

The handle is then rotated to cause the saddle to make firm contact with the load and further screw rotation causes the load to raise with a smooth movement.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

We claim:

1. A mechanical jack comprising, a pair of upwardly extending channels, one telescoping within the other and both having a slot along one of their corresponding sides, a threaded shaft rotatably mounted within the inner channel, a load-engaging saddle threadably connected to said shaft and extending through both of said slots, means for rotating said shaft to thereby cause the saddle to move relative to both of said channels, and releasable locking means carried by said inner channel and engageable with the outer channel whereby the inner channel and the saddle can be quickly moved as a unit relative to the outer channel and locked in any one of a plurality of positions relative thereto, said locking means having an actuating portion extending through the slot of said outer channel.

2. A mechanical lifting jack comprising, a pair of upwardly extending channels, one telescoping within the other and both having a slot along one of their corresponding sides, a threaded shaft rotatably mounted within the inner channel, a load-engaging saddle threadably connected to said shaft and extending through both of said slots, means for rotating said shaft to thereby cause the saddle to move relative to both of said channels, said outer channel having a series of spaced apertures along its length, and a spring-biased locking pin slidably carried by the lower end of the inner channel and adapted to selectively engage any one of said apertures in said outer channel whereby the inner channel and the saddle can be quickly moved as a unit relative to the outer channel and locked in any one of a plurality of positions relative thereto, said locking pin having a gripping and manipulating portion extending outwardly through the slot of said outer channel and adapted to coact with said outer channel when pulled outwardly and rotated to thereby retain said pin in disengaged condition during movement of said inner channel relative to said outer channel.

3. A mechanical lifting jack comprising, a pair of upwardly extending channels, one telescoping within the other and both having a slot along one of their corresponding sides, a threaded shaft rotatably mounted within the inner channel, a saddle nut threadably engaged by said shaft for running therealong when the latter is retated, a load-engaging saddle extending through both of said slots and having a portion forming a sliding fit with the interior of said inner channel and engaged by said nut, means for rotating said shaft to thereby cause the nut to move the saddle relative to both of said channels, and a releasable locking pin carried in a tubular housing secured to a lower portion of said inner channel and having one end resiliently urged toward locking engagement with said outer channel while the other end of said pin extends through said slots whereby the inner channel and the saddle can be quickly moved as a unit relative to the outer channel and locked in any one of a plurality of positions relative thereto.

References Cited in the file of this patent UNITED STATES PATENTS 918,062 King Apr. 13, 1909 953,157 Spencer Mar. 29, 1910 1,156,789 Lough Oct. 12, 1915 2,630,295 Lucker Mar. 3, 1953 2,711,183 Lofstrand June 21, 1955 FOREIGN PATENTS 1,032,608 France Apr. 1, 1953 124,910 Great Britain Apr. 10, l9l9

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