US2416753A

US2416753A - Counterbalance for ramps and like pivoted members

Info

Publication number: US2416753A
Application number: US601019A
Authority: US
Inventors: Hicks Albertson
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-06-22
Filing date: 1945-06-22
Publication date: 1947-03-04
Anticipated expiration: 1964-03-04

Description

A. HICKS Mar'ch 4, 1947.

COUNTERBALANCEIFOR- RAMPS AND LIKE PIVOTED MEMBERS Filddune 22 2 Sheets$heet l INVENTOR. ALBERTSON HICKS BY ll l8 March 4, 1947.

A. HICKS COUNTERBALANCE FOR RAMPS AND LIKE PIVOTED MEMBERS {Sheets-Sheet 2 Filed June 22, 1945 swim i5 lill In n ALBERTSON H CKS INVENTOR.

Patented Mar. 4, 1947 UNITED STATE COUNTERBALANCE FOR RAMPS LIKE- PIVOTED MEMBERS? Albertson Hicks, Miami, Fla.

Application 31311622, 194 5 Serial" No. 6'01",019

This invention relates to a spring counterbalance so associated with a horizontally pivoted member which swings gravitationally away from an upright position, as to yield to the weight of said member on the downward phase of itsswing, but to sustain a part of the weight of said member on its upward phase of swing so as to make it easier for an operator to pullsaidmember to its upright position.

Such a counterbalance has many useful applications, but is here disclosed and described in connection with the ramp of a landing boat. Such craft customarily are provided with a bow ramp for disembarking mechanized equipment, etc., upon a beach, horizontally pivoted to the craft at the bottom and normally held in substantially upright position by a cable, just enough ofi balance so that it falls outward and descends by gravity when the cable is payed out, until it rests upon the beach. Since the ramp is quite heavy, in the absence of a counterbalance tosustain part of the weight, the hauling up of the ramp is a relatively laborious and slow operation. Since it is generally expedient to leave the shore as soon as possible after landing, for making quick return trips, the counterbalance is an important adjunct to the operation of the ramp.

Counterbalances have. been used in this rela tionship, consisting of a strong spring so ar ranged as to be compressed by the gravitational descent of the ramp, thus storing up potential energy which is expended in assisting to lift the ramp while it is being drawn up by the cable.

For reasons to be explained, it is desirable that the counterbalances be effective quite to the limit of upward swing of the ramp, but where solely a strong spring is employed, this is impracticable, for the vertical component of gravity acting to lower the ramp when it is in its uppermost position, is so small as to be equaled or exceeded by the pressure of the strong spring, with the result that the ramp will not begin to descend by gravity, but must be given a manual push to start it.

One of the objects of the present invention is to provide a counterbalance comprising a strong spring which reaches the limit of its expansion before completion of the upward swing of the ramp, supplemented by a relatively Weak spring which assists in the completion of the upward swing of the ramp.

Another object of the invention isto provide a novel andsimple frame construction for supporting the movable elements of the counterbalance.

Other objects ofthe invention will appear as 4 Claims. (Cl-a 267- 70) plates 4' and 5.

the following'descr'iption of a preferred and prac tical embodiment thereof proceeds.

in the drawings: I

Figure 1 is a; vertical longitudinal sectionshowing the forward portion of a landing craft with the counterbalance in operative correlation to the ramp;

Figure 2 is a plan view of Figure 1;

Figure 3 is a longitudinal section through the counterbalance;

Figure 4 is a section taken along the line 44 ofFig ure 3; I

Figure 5 is a cross-section taken along 5-5 of Figure 4.

Referring now in detail to the drawings, the numeral l designates generally the counterbalance, the frame of which comprises apair of parallel tubular spaced spring housings 2 and 3,015 equal length, secured respectively by the head The head plate 4 bridges the space between the spring housings 2 and 3 and is the line formed with cup-like recesses 6 and 6, receiving the adjacent ends of the housings 2 and 3. The head plate 4 is also formed with the aperturedsupporting lugs! and 8, adapting the counterbalance to be mounted on a panel;

The head plate 5 comprises recessed portions 9 and I0, which fit over the opposite ends of the spring housings 2 and3, said portions being connected by spaced side members H and I2 which bridge the space between the spring housings, and have bearing'apertures which support the shaft l3 of thefixedsheave M. The head plate 5 is also provided with the apertured supporting lugs I5 and I6.

The head plates l-and 5 are apertured coaxially with the springhousings 2 and 3, to'receive the through bolts l1 and [8, having nuts at their opposite ends, and forming therewith means-for holding the head plates tightly against the ends of the spring housings. The axial recesses in the head plate 5 are countersunk to receive and hold against rotation the nuts on the adjacent ends ofthe bolts I1 and [8, so that adjustment is made from the nuts-on the opposite ends of saidthrough "bolts."

The head plateli is provided, within the spring housings 2 and 3, with cylindrical cups 1 9 and 20,

in which are seated the ends of light coil springs the springhousings 2 and 3 resting upon the ends of the strong springs 23 and 2t. Said end portions are connected by

narrow necks

32 and 33, which pass through the respective slots 26 and 21', with the spaced

hanger arms

34 and 5 ,be-= f tween which the sheave 3'6 is positioned, mounted upon a. shaft 3.! journaled in said hangers. '1'

Each sheave comprises a plurality of pulleys 38, there being three on each sheave in the embodiment illustrated, as shown in Figure 4, the pulleys of the respective sheaves being offset, as shown, so as to avoid interference bythe lifting rope which extendsirom the sliding sheave, with the adjacent pulley on the fixed sheave. With three pulleys on each sheave, as shown, an approach of twelve inches between the pulleys will result in a travel of seventy-two inches of the lifting rope.

on the sheaves when it is attempted to lower the ramp.

While I have in the above description disclosed a preferred and practical embodiment of the invention, it will be understood to those skilled in the art that the details of construction and arrangement of parts are capable of variation with- 1 out departing from the invention.

A cover plate 39 is shaped to snap overtlie about a direction changing pulley 44. A cable is attached to the equalizing block,- passes' several times about the winding drum 36, and then continues to the movable sheave of the counterbalance. It is then passed about the several pulleys of the counterbalance and secured toan eye on the fixed'sheave. The length ofthe cable 45 is such that when the ramp is in its fully up right position, the springs of the counterbalance are still under some compression. When the drum is turned in an unwinding directionthe ramp descendsby gravity, first compressing the light springs 2| and 22 until the latter are com- 7 pletely within the cups l9 and 20. During this period of descent of the ramp, the gravitational component is very small, but the spring is light and yields to said component. When the ramp has reached the position at which the light spring is fully compressed, its gravitational component is sufilciently great to overcome the strong springs.

, Further downward movement of the ramp, therefore, compresses the strong springs, the ends of which abut against the ends of the cups l9 and 2f]. When it is desired to raise the ramp, the drum 46 is turned'in a clockwise direction, referring to Figure l. Rotation of the drum is assisted by the expansion of the springs; the strong springs expandin until the ramp has almost reached its upright position. 7 The strong springs are of such length and tension as to become fully expanded, by the time this point is reached,

whereupon, the light springs then begin to expand and assist in lifting the ramp to its fully uprightposition. 7

If the'light springs were. omitted so that the counterbalance were not undergtension during 'the'final part of the upward swing of theramp,

What I claim as my invention is: l. Counterbalance for ramps and like pivoted members comprising a frame including spaced parallel cylindrical spring housings, a head plate at each end bridging the space between said housings and forming end closures therefor, and bolts extending-between said head plates securing them rigidly to said housings, spring means within each of said housings comprising a relatively strong spring of major length and a relatively weak spring of minor length, serially arranged, a iixed multiple pulley sheave between said housings jpurnaled in one of saidhead plates, the ad jacent sides of said housings having longitudinal slots therethrough in the common plane of their axes through an extent remote from said fixed sheave, a movable multiple pulley sheave be tween said housings, a carriage in'which said movable sheave is journaled having portions 6X5 tending through said slots and resting a ainst the adjacent ends of said spring means, and a cable threaded around the pulleys of said sheaves adapted to draw said sheaves together against the tension of said springs when the load end of said cable is pulled. 2. counterbalance housings and forming end closures therefor and bolts extending between said head plates securing them rigidly to said housings, spring means within each of said housings comprising a rela- 'fix ed 'sheave, a movable multiple pulley sheave between said housings, a carriage in which said movable sheave is journaled having portions ex tending through said slots and resting against the adjacent ends of said spring means, and a cable threaded around the pulleys of Said sheaves adapted to draw said sheaves together against the tension of said springs when the load end of said cable is pulled.

, Qounterbalance for ramps and like pivoted members comprising a frame, including spaced parallel cylindrical spring housings, a headplate ateach end bridging the space between said housings and forming end'closm'es therefor, and bolts extending between said head plates securing them rigidly to said housings, one of said head plates being provided with cups within said housings, spring means within each of said housings comprising a relatively strong Springof major length and a relatively weak spring of s for ramps and like pivoted members comprising a frame, including spaced parallel cylindrical spring housings, a head plate at each end bridging the space between said minor length, serially arranged, with the end of said relatively weak spring seated in said cup, the latter being of a depth to contain said relatively weak spring when fully compressed, a fixed multiple pulley sheave between said housings journaled in one of said head plates, the adjacent sides of said housings having longitudinal slots therethrough in the common plane of their axes through an extent remote from said fixed sheave, a movable multiple pulley sheave between said housings, a carriage in which said movable sheave is journaled having portions extending through said slots and resting against the adjacent ends of said spring means, and a cable threaded around the pulleys of said sheaves adapted to draw said sheaves together against the tension of said springs when the load end of said cable is pulled. a

4. .Counterbalance comprising a frame including spaced parallel cylindrical spring housings, a head plate at each end bridging the space between said housings and forming end closures therefor, and means securing said head plates rigidly to said housings, one of said head plates being provided with cups within said housings, spring means within each of said housings comprising a relativelystrong coil spring of major length and a relatively weak coil spring of minor length, serially arranged, an alining disk against which the adjacent ends of said relatively strong and relatively weak spring abut, said disc having portions fitting within each spring, the opposite end of said relatively weakspring being seated within said cup, the latter being of a depth to contain said relatively weak spring. with said disk seated on the end of said cup, when said relatively weak spring is fully compressed, a fixed multiple pulley sheave between said housings journaled in one of said head plates, the adjacent sides of said housings having longitudinal slots therethrough in the common plane of their REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 629,290 Goodbaudy July 18, 1899 1,243,526 Hughes et a1 Oct. 16, 1917 1,351,867 Oakes Sept. '7, 1920 2,364,901 Hicks -1 Dec. 12, 1944 1,813,078 Nyrop July '7, 1931 2,033,035 Koons Mar. 3, 1936 1,384,153 Roos July 12, 1921