US1630572A - Car truck - Google Patents

Description

y 1927- s. w. KADEL ET CAR TRUC K Filed May 20. 1926 2 Sheets-Sheet l May 31, 1927. 1,630,572

8. W. KADEL ET AL CAR TRUCK Filed May 20 1926 2 Sheets-Sheet 2 Patented May 31, 1927.

ITED 'STTES wasp PATENT BYIERS W. KADEL, OF BALTIMORE, MARYLAND, AND DONALD S. BARROWS. OF ROCHESTER, NEW YORK.

C TRUCK.

Application filed may 2-0,

This invention relates to railway car trucks and, more particularly, to the construction of the side frame and associated spring plank, spring plates and springs for reserv' ment of a side frame and associated spring 7 plank forming an upwardly opening pocket under one or more oi? the spring units supported thereby, whereby the supporting capacity of said spring unit or units is reserved until the other spring units are stressed a predetermined amount.

, Another object of our invention is the design of the side frame and associated spring plank and the arrangement of the springs and the construction of the spring plates therefor for permitting successive compression of said springs, the lower spring plate, for that purpose, being formed with a downwardly embossed portion receiving a portion of the nest of springs positioned therea-bove and allowing the same to remain at a lower level than the remainder of the nest of springs, the side frame and/or the s ring plank underlying said nest of springs ein formed to provide a pocket for receiving s'ai downwardly embossed portion of the spring plate so that the spring or springs supported in said downwardly embossed portion is or are not brought into action until after a predetermined deflection of the bolster.

A further object of our invention is the provision of an additional spring unit associated with an A. R. A. standard four unit nest of springs for increasing the capacity of car trucks with which employed, the associ'ated spring plates being formed to correspond with and reserve the extra spring unit and provided with means for locating the same with respect to the associated spring plank and bolster, the lower spring plate for said nest of springs being formed with a downwardly embossed portion or independently movable portion underlying the cen- 1926. Serial No. 110,511.

tral spring unit and received in a correspondmg recess underlying said additional spring un t whereby the capacity of said spring unlt 1s reserved until the other spring units have been compressed a predetermined amount.

Uther objects and advantages of the invention relating to the particular arrangement and combination of the various parts will begome apparent as the descri tion proceeds. Referring to the drawings i lustrating our inventlon, the scope whereof is defined by the appended claims:

Figure 1 is a fragmentary side elevation of a car truck, shown partly in section, and particularly illustrating the construction of the various members associated with the bolster springs.

Figure 2 is a horizontal sectional view on the line 22 of Figure 1 looking in the direction of the arrows.

Figure 3 is a transverse sectional view on the line 3-3 of Figure 1 looking in the direction of the arrows.

Figure 4: is a plan of the spring plank seat portion of the side frame,- the position of the sprlngs thercover being diagrammatically illustrated by dot and dash lines.

Figure 5 is a top plan of the bottom spring plate.

Figure 6 is a fragmentary transverse sectional view corresponding to Figure 3 and showing a modification.

Figure 7 is a fragmentary transverse sectional view corresponding to Figure 6 and showing a further modification.

Referring to the drawings in detail, like parts being designated by like reference characters, and first considering the embodiment of our invention illustrated in Figures 1 to 5, inclusive, a. truck side frame 1 is shown fragmentarily and is, in the present embodiment of our invention, of integral cast construction comprising a compression member 2, a tension member 3 and bolster guide columns or struts 4 spacing intermediate portions of said compression and tension members, leaving a bolster or window opening 5 therebetween. The .compresslon member 2, over the bolster opening, may be of substantially channel or inverted U shape in cross section, the bolster guide columns 4 are shown of similar construction at the bolster guiding portions thereof, while the tension member 3, beneath the bolster openilt) ing 5, is preferably substantially box shape in cross section. In this particular embodiment, the tension member 3, beneath the bolster opening, is formed with an upper web 6, a lower web 7, a front or outer web 8 and a rear or inner web 9, said webs 8 and 9 preferably remaining substantially upright for their entire length but positioned more widely apart beneath the spring plank seat portion for more efliciently supporting the springs located thereover. The web 7 is preferably of substantially uniform width except beneath the bolster opening where it is widened to correspond with the wider spacing of the webs 8 and 9. which extend from the edges thereof to the upper web 6. In order to form a spring plank seat portion of ample width, the web 6 is extended lat erally beyond the upper edges of the webs 8 and 9 forming outward or front flange or shelf portions 10 and inward or rear flange or shelf ortions 11.

The spring p ank 12 preferably rests directl on the upper web 6 of the tension mem er beneath the bolster opening which forms the spring plank seat portion and the up er surface of said seat portion is prefera ly provided with A. R. A. standard squaring lugs 13 which engage in corresponding apertures 14 in the spring plank for maintaining the desired relation between the spring plank and side frame. The end of the spring plank 12 is preferably formed with an embossment 15 to limit the outward shifting of the associated spring grou The len h of the spring plank is pre erably slig tly greater than a standard spring plank because of the additional spring group or unit with which it is adapted to be used in the present embodiment but it is to be understood that the broad principle of our invention may be em loyed in connection with man other em odiments involving the use 0 standard spring planks or spring planks constructed in any desired form. The width of the spring plank. at the ends thereof is slightly greater than normal because of the increased corresponding dimension of the spring nest with which employed, but the spring plank may be formed from a blank of standard width with the flanges decreased in height at the ends of the plank to correspond with the necessary increase in width for the accommodation of the preferred spring arrangement. As shown most clearly in Figures 1 and 2, the spring plank 12 is channel shape in cross section and the web thereof is formed with an aperture 16 so positioned that, when the plan is assembled with the side frame, it is located on the longitudinal center line of said frame, in a preferred construction.

Positioned on the web of the spring plank 12 is a spring plate 17eformed with a central depressed or downwardly embossed portion 18 fitting within the aperture 16 in the spring plank 12 and, in the present embodiment, of a depth greater than the thickness of said spring plank so that the web 6 of the tension member is formed with a depressed portion 19 of a size corresponding with the aperture 16 in the spring plank and the depressed portion 18 in the spring plate 17 for receiving said spring plate emossment, as shown particularly in Figures 1 and 3. It will be apparent that on account of the embossment 18 snugly fitting in the aperture 16 in the spring plank and depressed portion 19 in the web 6 of the tension member, said spring plate and the as sociated spring units 20 are properly positioned with respect to the spring plank and side frame. In the preferred embodiment of our invention illustrated, we preferably, but not necessarily, employ an A. R. A. standard four unit nest of springs positioned on the spring plate 17, but the units thereof are more widely spaced with respect to each other than normal for receiving an additional spring unit 21 centrally thereof. Each of the group of springs or spring units 20 and 21, preferably comprises, in accordance with usual practice, an outer coil 22 and an inner coil 23. All the springs are preferably positioned directly on the spring plate 17 and properly located with respect thereto by means of upstanding annular flanges or collars 24 which engage the innermost springs 23 of the spring groups 20 and 21.

In order toaccommodate the extra or reserved spring group or unit 21, the spring plate 17 is correspondingly extended in area, as shown most clearly in Figure 5, and formed with five instead of four spring loeating collars 24. The additional spring group 21 is referably centrally located with respect to t e other spring units 20 in accordance with the normal spacing between said springs and lies in the depressed portion or pocket 18 of the spring plate 17 which is formed of a size corresponding therewith so that, when assembled, it preferably lies on the lon udinal center line of the side frame and t e whole nest balances about said longitudinal center line, that is, its center of gravity corresponds therewith.

The upper spring plate 25 is preferably identical in outline with the lower spring plate 17 but is not furnished with a depression or. embossed portion like the lower spring plate but is instead preferably provided with locating bosses 26 arranged on the longitudinal centerline of the side frame, when assembled, and received in registering apertures 27 on the bolster 28. The collars 24 on the upper spring plate, of course, extend downwardly and engage the inner springs 23 of the sprin groups or units 20, the outer springs 22 being properly lit) positioned by being wound in an opposite manner compared with the inner springs and closely encircling said inner springs. ecause of the positioning of the central spring unit 21 in the depressed portion 18 of the spring plate 17, the upper end of said spring unit, if of a free height corresponding with the free height of the other spring units, does not initially engage said upper spring plate 25 or the central collar 24 therein but is spaced therefrom a distance corresponding to the amount of depression of the portion 18 of the spring plate 17. On account of the wider spacing of the original springs of the standard four unit nest of springs, it ma be necessary to extend the substantially orizontal spring engaging web or face 29 of the bolster 28 inwardly to 30 and said bolster is preferably of a length corresponding with the length of the spring plank.

For retaining the spring plates 17 and 25 in the desired assembled relation with respect to the springs therebetween, the spring locating collars 24 on said plates corresponding with the central unit or group of springs are referably formed with inwardly extending annular ledge portions 31 leaving openings 32 for the reception of a retaining bolt or other connecting means 33 extending therebetween with a headed portion and nut, respectively, engaging the ledge portions 31 on the spring plates 25 and 1 The spacing of the standard or outer four units is preferably such that the length of the nest in the direction of'the len th of the side frame corresponds with the olster opening so that the assembled nest of springs may be inserted through said opening and positioned over said spring plank seat portion of the frame with the necessary clearance only provided with respect to the bolster columns. The spacing of the four outer spring units in a direction transversely of the side frame or longitudinally of the spring plank is governed by the space necessary for the central spring unit 21 and, in accordance with this requirement and otherwise spacing the springs in this direction a minimum distance apart while still allowing normal clearance therebetween, it will be a parent that the spring arrangement is substantially or approximately square in outline, as shown most clearly in Figures 2 and 4. More particularly, the outline of the nest of springs is rectangular, the long axis of the rectangle extending transversely of the side frame, but being only slightly longer than the short axis thereof which extends longitudinally of said frame.

In order to allow for compression of the springs due to the load on the car, the upper web 6 of the tension member of the side frame is formed with an aperture 34 directly beneath the bolt of other retainlng means 33, said aperture extending through the depressed portion 19 in the web 6 of the tension member. The edges of the spring plank seat portion or upper web 6 of the tension member adjacent the aperture 34 are preferably reinforced by depending flange or collar portions 35 so that the strengthof the frame is not materially decreased by said aperture 34.

Onaccount of the provision of the upwardly opening depression 18 in the spring plate and the corresponding aperture 16 in the spring plank and the correspondin depression 19 in the spring plank seat of the side frame, provision is made for stressing the spring units successively rather than simultaneously. The corresponding aperture and the pockets and depressions are preferably circular and of sufficient size to ust receive the spring unit 21 with normal clearance and the depressions or pockets are of a depth corresponding to the compression of the other springs desired before "it is considered advisable to bring into play the additional or reserve spring capacity of the spring unit 21. For example, the depth of the pocket or recess 18 may correspond to one-half the full load compression of the other spring units so that the additional or reserve spring capacity will come into play only after one-half the rated load has been applied to the four outer spring units of the nest of springs, it being obvious that under such circumstances,ithe central spring unit, if of a size corresponding with the four outer spring units, would only be adapted for compression to one-half the rated full compression thereof and the arrangement shown would give an effective spring capacity corresponding to four and one-half spring units. The additional spring unit would come into play at an intermediate point of the compression of the other spring units so that the graph representing the deflection of the springs for increasing applied loads would increase in steepness at a point corresponding to the engagement of the extra spring unit. Of course, the foregoing is only a suggestion as we contemplate forming the recess or pocket 18 in accord ance with the conditions under which it is to be used and the effective depth of said pocket may be varied to get the most desirable operative conditions for the springs by the use of washers or shims in connection therewith for decreasing the depth of said pocket. We do not wish to be restricted to reserving the capacity of only the spring unit as shown in the present embodiment as, if desired, a different spring unit or a plurality of spring units may be reserved in a similar manner.

For adequately reinforcing the spring plank seat or upper web 6 of the tension member 3 for supporting the novel arran ement of springs in accordance with our mvention, said web 6 is preferably formed and reinforced as most clearly shown in Figures 3 and 4. It will be a parent that the front or outer flange or le ge 10 is extended in width to a maximum below the two outer spring units and extended at uniform width between said outer spring units. A similar construction for the flange or ledge 11 occurs beneath the inner pair of spring units. Approximately directly beneath the outer springs, the extended flange 10 is preferably reinforced and braced with respect to the web 8 by means of preferably triangular web or bracket portions 36 and the inwardly extending flange 11 is similarly reinforced by preferably substantially triangular web or bracket portions 37 extending directly beneath the inner spring units between said flange 11 and the inner web 9.

As a further reinforcement for the spring plank seat portion or web 6 of the tension member, the reinforcing collar or web 35 around the aperture 34 is preferably joined to the side webs 8 and 9, respectively, by depending ribs or webs 38 and 39 positioned directly under the transverse center line of the central spring unit 21, as most clearly indicated in Figure 4. From a consideration of this figure, particularly, it will be apparent that the webs or brackets 36 and 37 together with the collar 35 and webs 38 and 39 are positioned most efiiciently for adequately supporting the springs positioned thereover, especially as the efficiency of the arrangement is increased by the wider spacing of the side webs 8 and 9 directl beneath the spring plank seat portion 0 the frame. It will be apparent that although the aforedescribed reinforcement is especially designed for the five unit nest of springs arranged in accordance with our invention, yet upon filling u the pocket 19 and aperture 16 by means 0 a circular plate or washer of corresponding size, it is admirably adapted for supporting an A. R. A. standard four unit nest of springs when the same are positioned so that the center of gravity thereof lies on the longitudinal center line of the side frame.

Referring now to the embodiment of our invention illustrated in Figure 6, a construction is there disclosed which may be identical with that previously disclosed except that the pocket or recess 18 in the lower spring plate 17 is shallower than the recess 18 in the spring plate 17 and of a depth corresponding with the thickness of the spring plank 12. For this reason, it is unnecessary to form a pocket 19 in the side frame as in the previous embodiment and the to of the spring plank seat portion of said ame may extend at auniform eleva tion except, of course, for the squaring lugs 13. Except as specifically described, this second modification may be otherwise the same as the first modification.

Referring to the embodiment of our invention illustrated in Figure 7, the lower spring plate 17 instead of being formed as a single plate for supporting all five spring units, is formed with an aperture 40 large enough for receiving the central spring unit 21 with the normal clearance therebetween and a separate spring plate 18 is provided for said spring unit, said spring plate being constructed similarly to the central portion of the upper spring plate 25. The bolt 38* serves for holding the central spring plate 18 in proper relation with respect to the upper spring plate 25 and it is desirable to connect the outer spring'plate thereto by means of a plurality of retaining bolts, not shown, extending through appropriately embossed portions of the plates 17 and 25 in any desired manner, for example, as shown in our co-pending-application on car trucks, filed'of even date herewith. It will be apparent that, in this third modification, the top of the spring unit 21 is normally on the same level with the tops of the spring units 20 as contradistinguished from the position of the spring unit 21 of the other modifications and, on deflection of the bolster 28 and compression of the spring units 20. the central spring unit 21, instead of being immediately compressed, is moved downwardly into the pocket 19 in the spring plank seat portion of the side frame 1 and/or into the corresponding aperture 16 of the associated spring plank 12. In other words, the side frame 1 may be formed with or without a pocket 19 or in accordance with Figure 3 or Figure 6 depending on the'point at which it is desired to bring the reserved spring 21 into action. Except as specifically described in connection with Figure 7, the construction of this third modification may be the same as that illustrated in Figures 1 to 5, inclusive.

From the foregoing disclosure, it will be 'seen that we have devised a construction which provides for a reserved spring capacity approaching twenty-five percent of the initial spring capacity with a reserved spring unit like the other spring units and adapted for considerable variation either way by using a stronger or weaker secondary or reserved spring unit without radically changing the construction of the side frame and spring plank. Although the arrangement has been shown in connection with a normal design for fifty-five ton side frames yet, as is obvious, it is not limited to frames of such capacity and the broad idea of forming a poc et in lower spring plate and side frame together with a corresponding aperture in the spring plank under a portion of the bolster s rings for reserving a certain proportion o the spring capacity until after the remainder of the springs are stressed a predetermined amount may be utilized with any desired type of frame, bolster, spring plank and associated springs and spring plates.

Having now described our invention, we claim:

1. In a car truck, in combination, a side frame formed with a bolster opening and a spring plank seat portion underlying said opening, a spring plank supported on said spring plank seat portion, a nest of springs of uniform normal height supported by said spring plank seat portion and spring plank, and a bolster supported by said nest of springs, said spring plank being so constructed that the springs will be successively loaded.

2. In a'car truck, in combination, a side frame formed with a bolster opening and a spring plank seat portion beneath said opening, a spring plank supported on said spring plank seat portion, a nest of springs supported by means of said spring plank seat portion and spring plank, and a bolster supported by said nest of springs, said spring plank being so constructed that certain of the springs are initially stressed and the remainder of the spring capacity is brought into play after the bolster has been deflected a predetermined amount.

3. In a car truck, in combination, a side frame formed with a-bolster openingand a spring plank seat portion underlying said opening, a spring plank supported on said spring plank seat portion, a nest of springs supported on said spring plank and said spring plank seat portion, and a bolster supported by said nest of springs, said spring plank and spring plank seat portion of the frame being constructed so as to provide a pocket underlying a portion of the nest of springs whereby certain of the springs are initially stressed by movement of the bolster and the remainder of the nest of springs comes into action only after a predetermined amount of bolster movement.

4. In a car truck, in combination, a standard side frame formed with a bolster opening of normal size and a standard spring plank seat portion underlying said opening, a nest of sprin supported by said spring plank seat portion and a bolster supported y said nest of springs, said spring plank being provided with an aperture under one of the spring units of said nest of springs whereby said unit is not stressed by the bolster until after movement thereof corresponding to the thickness of the spring plank. v

5, In a car truck, in combination, a side frame formed with bolster columns leaving a window therebetween normally adapte for a four unit nest of springs and a spring seating area beneath said opening,'a five unit nest of springs supported by said spring seating area and arranged with two pairs of transversely disposed springs, longitudinally spaced to allow just sufficient clearance with respect to the bolster columns, the spring units of each pair being spaced sufiiciently for receiving the fifth spring unit centrally disposed with respect thereto, and a bolster supported by means of said nest of springs, said spring seating area being formed with a depression directly beneath the central spring unit and receiving the lower end thereof, whereby said bolster is initially supported by only the four outer spring units until after a predetermined movement thereof corresponding to the depth of the depression, when it is supported by the five units of the nest of springs.

6. In a car truck, in combination, a side frame formed with a bolster opening and a spring plank seat portion beneath said opening, a spring plank positioned on said seat portion, a five unit nest of springs supported on said spring plank and seat portion of the frame, four of said spring units being arranged approximately as a square in outline and formed as two pairs of spring units positioned, respectively, inwardly and outwardly of the longitudinal center line of the associated side frame, the units of each pair being spaced as far apart as possible yet close enough together to allow sufficient clearance for insertion in the bolster opening, the corresponding spring units of the pairs of springs bein spaced sufficiently transversely of each 0t er for allowing the fifth spring unit to be positioned centrally with respect to the four spring units, a bolster supported by said nest of springs, said spring plank and spring plank seat portion of the frame being formed to provide a recess underlying the central spring unit and receive the lower end thereof, whereby the capacity of said central spring unit is reserved until after a predetermined compression of the other sprmg units.

7. In a car truck, in combination, a side frame formed with a compression member, a tension member and bolster guide columns spacing intermediate portions of said compression and tension members leaving a window opening therebetween, that portion of the tension member, beneath the window opening, being laterally widened to form a spring plank seat portion, a sprin plank supported on said seat portion, a ve unit nest of springs supported on said spring plank and seat portion, four of said units being arranged in rectangular formation with the long dimension disposed transversely of the side frame and only slightly longer than the short dimension, the outer rectangular outline of said springs being short enough for insertion between the bolster columns and wide enough for receiving the fifth spring unit centrally of the springs with suflicient clearance therebetween, a bolster, the corresponding end of which is supported by the springs, and upper and lower spring plates for said spring units serving to roperly space the same with respect to ea other, the spring plank and bolster, said lower spring plate being formed with a downwardly embossed portion receiving the lower end of the central s ring unit and received in a pocket forme by the spring plank and spring plank seat portion wherey said unit is not compressed until after a predetermined deflection of the bolster.

8. In a car truck, in combination, a side frame formed with a compression member, a tension member and bolster guide columns spacing intermediate portions of staid compression and tension members leaving a window opening therebetween, a spring plank seat ortion beneath said window opening, a spring plank supported on said seat portion, a five unit nest of springs supported on said spring plank and arranged with one of the spring units centrally disposed with respect to the other four units, a bolster, the corresponding end of which is supported by the springs, and upper and lower spring plates for, said spring units serving to properly space the same with respsjct to each other, the spring plank and lster, said lower spring plate being formed with a downwardly embossed portion receiving the lower end of the central spring unit and received in a pocket formed by the ring plank and spring plank seat ortion w erey said unit is not compresse until after a predetermined deflectionof the bolster.

9. In a car truck, in combination, a side frame formed with a bolster o ening and a spring plank seat portion on erlying said opening, a standard four unit nest of springs supported by means of said spring plank and seat portion and an additional spring unit of the same size as the units of the nest of springs centrally disposed with respect to the four units, said four units, for that purpose, being moved longitudinally toward the corresponding ends of the side frame until just enough clearance remains for insertion in the bolster opening and moved transversely toward the corresponding sides of the side frame until just enough clearance is provided for insertion of the fifth sprin unit centrally thereof, a bolster supporte by means of said s rings, said spring plank and side frame ing constructed to provide a recess underlying the central spring unit and ada ted for receiving a ortion thereof where y the capacity of sai spring unit is reserved until after a redetermined compression of the other spring units.

10. In a car truck, in combination, a side responding spring units 0 frame formed with a bolster opening and a spring plank seat portion underlying said opening, a nest of springs of uniform normal height supported by said spring plank seat portion, and a bolster supported by said nest of springs, said spring plank bein so constructed that the springs will not simultaneously loaded.

11. In a: car truck, in combination, aside frame formed with compression and tension members spaced at intermediate portions thereof by bolster guide columns to define a bolster opening and a spring plank seat ortion underlying said opening, a spring p ank supported on said spring plank seat portion, a nest of springs supported on said spring plank and spring plank seat portion, and a holster supported on said nest of springs, the construction of said spring plank being such that the major portion of the load is carried by the springs adjacent the bolster guide columns, thereby relieving the central portion of the nest of springs of maximum stresses.

12. In a car truck, in combination, a side frame formed with a bolster opening and a spring plank seat portion underlying said opening, a spring plank supported on said spring plank seat ortion, a nest of springs supported on said spring plank and said spring plank seat portion, and a bolster supported by said nest of springs, said spring plank and spring plank seat portion of the frame being constructed so as to provide a portion at a lower elevation than the adjacent spring supporting surface underlying a part of the nest of springs whereby certain of the springs are initially stresed by movement of the bolster and the remainder of the nest of springs comes into action only after a predetermined amount of bolster movement.

13. In a car truck, in combination, a side frame formed with a bolster opening and a spring plank seat portion beneath said opening, a spring plank positioned on said seat portion, a five unit nest of springs supported on said spring plank and seat portion of the frame, four of said spring units being arranged a proximately as a square in outline and ormed as two pairs of spring units positioned, respectively, inwardly and outwardly of the longitudinal center line of the associated side frame, the units of each i c ose being spaced as far apart as possible yet enough together to allow sufficient clearance for insertion in the bolster o ening, the corthe pairs of springs being s aced sufiiciently transversely of each other or allowing the fifth spring unit to be positioned centrally with respect to the four spring units, a bolster supported by said nest of springs, said spring lank and spring la'nk seat portion of the rame being forme to provide a recess underlying a. part only of said nest of springs and reoelve the lower portion thereof, whereby the capacity of said part is reserved until after a predetermined compression of the remainder.

14. A side frame formed with a. spring plank seat portion adapted to provide a support for a nest of springs, said spring plank seat portion being formed with an upwardly opening substantially cylindrical centrally positioned recess for reserving the capacity of a portion of said springs until after a predetermined compression thereof.

15. A spring plank adapted for receiving a nest of springs at each end thereof and formed with a substantially circular perforation underlying a portion of each nest of springs for receiving the same and reserving the capacity thereof until after a predetermined compression of the remainder of said springs.

16. A spring plate for a nest of springs formed with a boss adapted to engage within a centrally positioned spring unit of the nest and perforated for the reception of a retaining olt, a portion of said plate concentric with said boss being embossed and of a sufficient size for receiving a portion of said nest of springs whereby the capacity of said portion is reserved until after a compression of the remainder of the nest of springs equivalent to the depth of the embossment has been effected, that portion of the plate exterior of the embossment being provided with annular flanges for properly locating the other spring units.

17. A spring plate for a nest of springs formed with an embossment of a sufficient size for receiving a portion of said nest of springs whereby the capacity of said portion is reserved until after a compression of the remainder of the nest of springs equivalent to the depth of the einbossment has been effected, that portion of the plate beyond the embossment being formed with upstanding collars adapted to properly center the remaining spring units.

In testimony whereof we afiix our signatures.

BYERS W. KADEL. DONALD S. BARROWS.

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