US2386571A - Cantilever spring - Google Patents

Description

Oct. 9, 1945.. .1. w. PETTIT CANTILEVER SPRING Filed'oct. 24,1942

M WM .h M m m W E. m F V f5 4, JW. U w 4 w J r n NV H F 5 RV, WA NA z MM MM NV xw l m WA Y LW my Km w N Patented Oct, 9, 1945 UNITED STATES PATENT OFFICE 2,386,571 CANTILEVER SPRING James w. retta, portland, oreg. Application 'October 24, 1942, Serial No. 463,203

1 Claim.

I j the manner set forth in the followingv specification, as illustrated in the accompanying drawing,

in which:

Fig. 1 is a plan of the spring.

Fig. 2 is a. side elevationof the spring.

Fig. 3 is a section taken along the line 3 3 in Fig. 2.

Fig, 4 is a section taken along the line 44 in Fig. 2.

Fig. 5 is a section taken along vthe line 5 5 in Fig. 2. l

Similar numerals refer throughout ther several views.

Referring in ydetail to the drawing, there is shown a rectangular frame consisting of the sides I and ends suitably secured at the corners I2, Alongthe top edge of each end is secured a strip I3. l

Along each side I0 is secured an inclined strip I4 which ail'ords rigidity to the sides I 0 and forms a support for the transverse fulcrum bars I which are notched at the ends I6 to receive the inclined strips I4. The bars I5 are also provided with notches Il on their upper sides to receive the upper spring leaves I8 and the lower spring to similar parts leaves I9, the purpose of which is to afford thel vthe spring ends 2| as shown, in order tounify the spring elements and resist the tendency to sag. It is also desirable to provide a transverse tie 23 across the middle of the unit directly under the spring ends 2|, and to unite each spring end 2| to the tie 23 by means of a cord 24 in order to provide a desired amount of initial tension to the leaves.

Obviously, the sizes and proportions of the parts Will depend upon the purpose for which they are used, as well as the materials from which they are made.

It can be seen from the foregoing, that by means of this construction, there is provided an inexpensive, comfortable, and practical spring unit which lends itself to use in connection with furniture, automobile cushions, etc. greatly lightening the unit and avoiding the use of essential War materials. For small units, single oantilevers would be employed instead of the double `as shown.

The purpose in inclining the members I4 is to provide adjustability for the spring tension in the members I8 and I9. That is, as the bars I5 are movedtoward theV middle of the structure, the strength of the spring is increased, and as the bars I5 are moved toward the ends II, the springs are rendered. more flexible. Owing to the flatness of the angle of the members I4 it is not necessary to provide any means for preventing the movement thereof.

I claim:

In the'cantilever spring unit, the combination of a rectangular frame having fulcrum bars .placed transversely across same near the ends thereof, each of said fulcrum bars having resting thereon a plurality of inclined spring leaves, one end of each of which is supported Iby the end of the frame and the other end of which is unsupported and extends beyond the center of the spring frame, the spring leaves from the two sets of fulcrum bars` alternating, inclined cleats on said frame substantially parallel with said leaves and supporting said bars, said bars being adjustable along said leaves, and flexible means for uniting the overlappingends of said leaves, and tie strings between said overlapping leaf ends and said frame adapted to impose an initial tension on said leaves.

JAMES W. PETTIT.

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