US2456646A

US2456646A - patterson

Info

Publication number: US2456646A
Authority: US
Publication date: 1948-12-21
Anticipated expiration: 1965-12-21

Description

1366- 21, 1943. l J. E. PATTERSON SAFETY DEVICE FOR HOISTS Filed Aug. 12, 1944 Patented Dec. 21 1948 sarcoma I csaaaflsaavwmonflmsrs Junm-Evran rsoam wneeiar'rex.

a clar net/a s thereon.

Ihepresent invention pertains to a novel safety I 1 device for a..J:1qis,t .embodying a hydraulic plunger, such as those used in autocmntheimmir shuns.

The object of the invention-aisqtoaprovidea device to ,preventthahoist fromttalling or slippi from the elevated position'because of leakage of the hydraulic system or any other cause. :It-is wvident "Mata-hoist that us likely to slipnor =fall data .constant hazard to. a mam-working-eundermutant. 1

This object is accomplished byzmeansiota leg. or a pair of legs, pivotallysuspended from the platform of me lidlstand-ocoupying a vertical position, when the hoist is elevated. Theghpist fib -dr p or ip onlytuntn the ats leg rests on the floor. When the hoist is to be lowered, the leg is swung upward and into a latch carried by the platform. This latch embodies a release finger which, on engaging the floor, releases the leg and places it in readiness to assume the vertical position when the hoist is again elevated. The platform also carries another latch adapted to receive and retain the leg in the vertical position so that the leg will not swing when coming into contact with the floor.

An illustrative embodiment of the invention is disclosed by way of example in the following description and in the accompanying drawing in which:

Figure 1 is a plan view, partly broken away, of a hoist embodying the present invention;

Figure 2 is a cross section taken on the plane indicated by the line 2-2 of Figure 1;

Figure 3 is a cross section taken on the plane indicated by the line 33 of Figure 2;

Figure 4 is a plan view of the structure shown in Figure 3, and

Figure 5 is a fragmentary plan view, partly in section, illustrating the latch for holdin the leg in vertical position.

In Figure 1 is shown a hoist or lift including a hydraulic plunger I surmounted by a head 2 carrying a pair of horizontal rails or channels 3 in the usual manner. The rails support at one or both ends a cross shaft 4 which is preferably rotatably mounted. On each shaft is mounted a leg 5 adapted to swing about the axis of the shaft and which may be secured rigidly to the shaft if the latter is rotatably mounted. If two shafts 4 are provided, as in the preferred construction, the legs 5 are diagonally related to each other. The

-ebrresponding latches associated with eachdeg'fs are identical, and' only one set need theneforfe be described in detail.

Each rail 4 carries aiclip including a "downwavdly faoingeoncaveonember 6 having .an outwrardly axtending lug l fastened to the basemf thechannel thy bolts}. Themember-fiis positioned to receive the eorrespondinglegiwhenfthe latter is swung to a horizontal position. i An apertured lug '91s formedupon-the-extension I andis provided with a-hole 'Hl alined, with a similarlrole l'llh. thememberfli. In-these holes is islidagbly mounted a lockin pin 12 havingyarounded end "i3-disposed :within the memberfi and-adapted to engage theleg ireceived-therein. Alaterallyextending P 4 4 -is secured to i the base of the lug 8 for a purpose "that-will presently be described. Onone-end---of=the-locking pin: 12 is mounted a 'washer15 backed-bra cotterpin I6. "Next, to the washerismounted a disk'fl 'i1aving a laterally a n boss t fidi k norma ea against-one side of'thememberfi.

On the pin I4 is rotatably mounted a bell crank lever having a long arm I8 extending towards the member 6 and a short arm I9 extending towards the disk II. The arm I9 carries a pin 20 rotatably received in the boss I8. The bell crank lever is held on the pin I4 by a cotter pin 2|. The free end of the longer arm I8 is formed with an outwardly extending threaded stud 22 on which is fastened a trip leg 23 by means of a nut 24. The leg 23 has a slot 25 receiving the stud 22 and permitting the leg to .be locked in selected positions to the arm I8.

Another cotter pin 26 is passed through the locking pin I2 in a position to engage the outer surface of the member 6. Against the pin is a washer 21, and between the washer and the member 8, the pin I2 is surrounded by a compressed coil spring 29.

As the hoist is being raised, the leg 5 is free from the clip 6 and reaches a vertical position when the hoist is fully raised. In this position it serves as a safety leg or stop to support the hoist in case the plunger I slips in its cylinder. When the hoist is to be lowered, the leg is lifted and forced into the clip 6 over the rounded end I3 of the locking pin I2 and is then held by the pressure of the spring 29 on the locking pin. As the hoist reaches its lowest position, the trip finger 23 engages the floor and swings the bell crank lover I8, I9 retracting the pin l2 and permitting the leg 5 to fall out of the clip in readiness for the next elevating operation.

Slightly below the shaft 4 and adjacent to the with a notch 31 for a purpose that will presently appear. Adjacent to the notch, the edge of the plate 30 is formed with a recess 38 adapted to receive the leg when in the vertical position. The

leg is formed with a rib 39 that snaps into the '2 notch 31. Thus, the leg remains locked in the vertical position when it takes the weight of the hoist. Before swinging the leg into the clip 6, as previously set forth, the finger 33 is obviously swung away from the rib 39 by pressure on the unnotched end thereof. Adjacent to the finger, the plate 30 is formed with a lug 40 to limit the movement of the finger under the action of the spring 36.

While a. specific embodiment of the invention has been shown and been described, it will be understood that variousalterations may be made without departure from the spirit of the invention as indicated by the appended claims.

WhatI claim is:

.1. In a hoist having a platform, a leg having its upper end pivotally attached thereto on a horizontal axis and adapted to swing by gravity to a vertical position, a bracket attached to said platform at a point thereon spaced from said axis and having a flange engaging said leg to limit upward pivotal movement thereof, a latch member movably mounted on said bracket, a spring arranged to move said latch member into engagementwith said leg to hold said leg in locked position adjacent said bracket, a pivotally mounted bell crank lever arranged to move said latch member,

and a finger carried by said bell crank lever and extending below said platform for engagement with the ground to retract said latch member when the platform is lowered.

2. In a hoist having a platform, a leg having its upper end pivotally attached thereto on a horizontal axis and adapted to swing by gravity to a vertical position, a bracket attached to said platform at a point thereon spaced from said axis and having a flange engaging said leg to limit upward pivotal movement thereof, said bracket having a second flange spaced from said first mentioned flange and said flanges being provided with aligned openings therein, a latch member slidably mounted in said openings, a spring arranged to move said latch member into engagement with said leg to hold said leg in locked position adjacent said bracket, a bell crank lever pivotally mounted on the second mentioned flange of said bracket and having one leg engageable with said latch member, and a finger extending downwardly from the other leg of said bell crank lever and below said platform for engagement with the ground to retract said latch member when the platform is lowered.

- JULIAN E. PATTERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNI [TED STATES PATENTS Australia May 23, 1939