US1802299A - Method of making volute springs - Google Patents

Description

April 21, 1931. w. E. WINE METHOD OF MAKING VOLUTE SPRINGS Filed May 1928 FIG. 2

FIG

m'zzlam E FIG. 6

FIG.

Patented Apr. 21, 1931 Unitas stares PATENT OFFICE WILLIAM E. VINE, OF WASHINGTON, DISTRICT OF COLUMBIA METHOD OF MAKING VOLUTE SPRINGS Application filed. May 1,

The invention relates to volute springs face. Realizing the undesirable characteristics of this construction, engineers and manufacturers have resorted to the plan of cutting away the corners so as to obtain an initial area contact between the end portions of the spring and the elements between which it is located. However, this is only a partial remedy and is open to objection in- I asmuch as the removal of a portion of the material detracts to acertain extent from a the capacity and mechanical strength of the spring. Furthermore even this construc- I tion fails to provide adequate seating or I bearing surfaces.

It is with the above facts in view that I have devised the present invention which has for its general object the method of making a volute spring having large and adequate bearing surfaces for engagement with the coacting elements, the method being moreover such that none of the material is removed.

An important object of the invention is to provide a method of preforming the bar or stock from which a volute springis to be made with portions which provide'relatively large bearing areas for engagement with coacting elements. v p p A more specific object of the invention is to provide a method of preforming a bar or spring stock with hearing portions which n are substantially parallel when the stock or into-,the desired location.

bar is coiled into volute form, the method involving forging or otherwise treating the stock tonpset a portion thereof or force it I g and extending insubstantially parallel rela- 1928. Serial No. 274,307.

Another object of the invention-is to construct a volutespring in such manner that the bearing portions for coaction with other elements willextend laterally at the side'of the bar or stock, the direction of extension being such as to avoid anyinterference with the relative movement of the successive convolutions of the spring.

, Anadditional object of theinvention is to makea volute springhaving the above men'- tioned characteristics and advantages accruing therefrom without, however, involving any complex methods of manufacture and requiring only onestep in addition to the usual method of manufacture, the cost of production being consequently maintained comparatively low.

.To the attainment. of he foregoing and other objects and advantages the invention preferably consists in the methodto be hereinafter more fully described and claimed and illustrated in the ingin' which: I

Figure lisan elevation of a bar or stock from which a volute spring is to be made,

Figure 2 is a fragmentary side elevation of one end portion of the bar showing it associated with a forging machine, the latter being diagrammatically represented,

Figure 3 is a, plan view of the lower or anvil member with the end portion of the spring bar or stock operatively engaged therewith, r a

Figure i is a cross sectional view taken on the line 4-4 of Figure 2 showing the initial condition of the spring bar or stock. Figure 5 is a view-similar to Figure .4, with the upper or hammer member omitted and showing the material of the bar or stock upset to formthe seat portion,

Figure 6 is a side elevation of the completed spring, and Figure 7 is a plan'view of the spring.

Briefly considered ny invention consists accompanying drawing the diagonally opposite corner portions of a bar or spring stock to form surfaces inclined with respect to the longitudinal edges, these surfaces'being laterally enlarged in forging, hammering or otherwise treattion when the bar or stock is coiled into volute form.

Referring more particularly to the drawing, in Figure 1 there is shown a bar 1 of suitable spring material and of any desired dimensions depending upon the proposed travel and capacity of the spring to he made. Ordinarily the bar is simply coiled into volute form or else may have its diagonally opposite corners cut away as indicated by the dotted lines 2 and 8, these being the desired locations of the areas of engagement with the elements between which the spring is to be used. In carrying out my invention instead of cutting away the stock along these lines I mash over or upset the material laterally so as to form the seats. This may of course be accomplished in different ways and by means of any suitable machine or apparatus. However, in Figures 2, 3 and t I have shown, somewhat diagrammatically, a portion of a forging machine or die means for accomplishing the desired result. The lower die or anvil mem- 7: her 4 may be formed of one or two parts as desired but aside from this detail it is constructed with a longitudinally extending slot or socket 5 having an inclined bottom 6 and of such size as to receive either end portion of the bar 1 with the corner thereof projecting above the die or anvil member, the top of which should coincide with the line 2 or 3 as the case may be. At one side of the slot or socket the upper portion of this die or anvil member is formed with a wedge shaped or tapered recess 7 which decreases in Width and. height from its inner end or away from that end of the bar enga ed within the slot or socket, as indicated in igure 3. I

In making the spring, one end of the bar is engaged within the slot or socket 5 with the corner projecting above the die to the desired extent. The relatively movable hammer member or upper die 8 of the forging machine or analogous device is then brought down onto the projecting corner of the bar so as to upset or mash over the material thereof and force it into the Wedge shaped recess 7. \Vhen this is done it is apparent that there is provided a seating or bearing surface 9 which is inclined with respect to the longitudinal edge of the bar and which is relatively wide and otherwise of considerable area as compared with the edge of the bar itself. The diagonally opposite corner of the bar is treated in a corresponding manner by means of similar dies, the only difference being that the recess 7 in the die for this second end must be at the opposite side of the slot or socket from that shown in Figure 3 inasmuch as when the bar is coiled into volute form, as shown in Figure 6 by any well known means, the ribs 10 and 11 formed by mashing the material into the recesses must be located respectively exteriorly and interiorly. In other words the rib 10 at the largest convolution is on the outside whereas the corresponding rib 11 at the smallest convolution must be at the inside in order to avoid interference with relative movement of the convolutions. The length. of the rib 10 is probably more or less immaterial though in actual practice it may very likely extend along or throughout an arc of from to The rib 11 at the smaller end, indicated by dotted lines in Figure 6, would necessarily be of less length though it may be in the same proportion. Of course when the bar is coiled into volute form it must be tempered but details in regard to this need not be entered into for the reason that they form no real part of the present invention which is concerned only with the upsetting and flattening of the corners to provide the bearing areas.

Assuming that the spring has been constructed or formed as indicated above it is used in the same manner as any other spring of this type and will perform its function of providing yielding resistance in a well understood manner. he ribs will not interfere with the provision of either external or internal guide or centering means for the spring and such of either type may be employed though none is illustrated as likewise having no particular bearing on the invention. Owing to the particular formation which provides the large areas where the end portions of the spring are intended to abut against the surfaces of relatively movable parts, wherever the spring is used, the device should be highly satisfactory for the purpose intended.

In some instances volute springs are made from bar stock which is tapered in thickness so that the exterior of the outermostconvolution and interior of the innermost convolution will be cylindrical to facilitate or simplify installation and to permit engagement of the outer convolution within a cylindrical pan member or the like and to permitthe use of a cylindrical guide or centering pin or the like within the innermost convolution. If the spring be formed from such tapered stock it is quite apparent that the bearing areas will be very small and this is particularly true in connection with the innermost convolution. By upsetting the corners of the stock as disclosed above this objection is avoided. In some instances it may be found that the outer convolution will have a sufiicient bearing area without providing it with the laterally upset rib which I have described and shown. However, even though the inner convolution is not tapered in thickness and even though it be beveled off to provide an initial bearing area when there is no load, the bearing area is necessarily limited as the spring stock is never verythick. My invention may therefore be considered as having its greatest importance when applied to the inner convo-' lution. The fact that the presenceof the laterally offset or upset rib to provide the large bearing area at the inner convolution will probably require the provision of a guide or centering element which is of some shape other than cylindrical, for instance more or less ellipsoidal, is no drawback as this is an extremely small matterwhich can be allowed or provided for. It is believed that the advantages will be readily apparent to one skilled in the art without further explanation. I v

While I have shown and described certain details involved in the method steps and have illustrated certain definite die elements it should of course be understood that I reserve the right to make all such changes in these respects as will not depart from the spirit of the invention or the scope of the claims hereunto appended.

Having thus described the invention, I claim:

1. The method of making a volute spring from a bar, comprising upsetting diagonally opposite ends of the bar laterally to define bearing portions, and coiling the bar into volute form with said bearing portions at the opposite ends thereof. Y

2. The method of making a volute spring from a bar, comprising upsetting diagonally convolution and thelaterally upset portion opposite ends of the bar laterally to define bearing portions, and coiling the bar into volute form with said bearing portions at the opposite ends thereofrand substantially parallel.

i 3. The method of forming a volute spring from bar, comprising laterally upsetting the diagonally opposite corners of the bar along lines inclined with respect to the longitudinal edges to define substantially wedge shaped ribs. having relatively large bearing surfaces, and coiling the bar into volute form whereby said ribs will occupy positions at the ends of the spring for engagement with coacting elements.

4. The method of making a volute spring 7 from a bar, comprising laterally upsetting diagonally opposite corners of the bar in opposite directions, andcoiling the barinto volute form to define a plurality of convolutions, the laterally upset portion of one corner extending outwardly from one endmost of the other corner extending inwardly from I V the other endmost convolution.

of the bar with a portion unconfined, and

applying pressure to said unconfined portion to upset the same laterally for forming a substantially wedge shaped bearing portion, and coiling the bar into volute form.

7. The method of making a volute spring comprising confining diagonally opposite ends of the bar with portions thereof left unconfined, and upsetting said unconfined portions laterally in opppsite directions and then coiling the bar.

8. The method of making a volute spring comprising swaging a corner of a bar to upset the material along a line inclined with respect to the longitudinal axis to form a laterally widened bearing portion merging into the body of the bar, and coiling the bar into volute form.

9. The method of making a volute spring comprising forming a corner of a bar with a bearing portion inclined with respect to the longitudinal axis, and coiling the bar into volute form.

10. The method of making a volute spring comprising upsetting one corner of a bar along a line inclined with respect to the longitudinal axis to form a bearing portion, and coiling the bar into volute form.

In testimony whereof I ailix my signature.

WILLIAM E. WINE.

opposite corners of the bar to upset the .7

material along lines inclined with respect to the longitudinal axis of the bar to form laterally widened bearing portions merging

Images