US2044503A - Spring system for railway car trucks - Google Patents

Description

June 1936. w. R. HEWITT SPRING SYSTEM FOR RAILWAY CAR TRUCKS Filed July 19, 1952 2 Sheets-Sheet l INVEN TOR.

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A TTORNW June 16, 1936. w. R. HEWITT 2,044,593

SPRING SYSTEM FOR RAILWAY CAR TRUCKS 7 Filed July 19, 1952 V 2 Sheets-Sheet 2 Q INVENTOR.

Patented June 16, 1936 UNE'E'ED STATES PATENT SPRING SYSTEM FOR RAILWAY CAR TRUCKS This invention relates to a spring structure and mounting such as used in railway car trucks, and especially to a combination structure employing semi-elliptical and helical springs.

The recently developed need for smooth riding freight car trucks at modern high operating speeds and increased loads has created a demand for material improvements in the conventional spring suspension at present employed.

Tests show that the conventional helical spring truck gives fairly satisfactory riding qualities at some speeds but that at certain critical speeds vertical oscillations build up destructive forces acting on the car parts and lading equivalent to an increase of one hundred per cent or more of their dead weight. Critical speeds differ with the conventional helical spring truck when the frequency with which impulses are transmitted to the springs coincides with the natural period of oscillation of the springs. Because of the lack of energy absorption of helical springs, the oscillation then may become synchronous and amplified to a violent extent.

The object of the present invention is to generally improve the construction and operation of spring mountings such as employed in railway car trucks, and particularly to provide a spring combination in which the load is proportionately carried by two sets of springs having diiferent periods of vibration so as to provide smooth cushion action at difierent speeds and loads with substantial freedom from undesirable oscillations.

The invention is shown by way of illustration in the accompanying drawings, in which- Fig. 1 is a side elevation of a car truck showing the spring suspension employed.

Fig. 2 is a cross section taken on line IIII of Fig. 1.

Fig. 3 is a plan section taken on line III-III of Fi 1.

Fig. 4 is a perspective view of the hanger block and the anti-friction bearing plate cooperating therewith.

Referring to the drawings in detail, and particularly Figs. 1 and 2, A indicates the truck frame proper, equipped with axles B, wheels C,

and helical springs D to support a bolster E. The

bolster employed in the present instance is of substantially standard construction in as far as its attachment to the body frame is concerned, but the outer ends of the bolster are modified to permit a novel form of spring suspension.

The spring suspension employed in the present invention is a combination spring comprising the helical springs D placed below the bolster and a semi-elliptical spring F placed above the bolster. The outer ends of the semi-elliptical spring are attached to the truck frame A by means of shackles 2, while the bolster is suspended from the central portion of the spring as follows. Surrounding the center portion of the spring is a hanger block generally indicated at 3, see Figs. 1 and 4. The center portion of the semi-elliptical spring is secured in the block in any suitable manner. The block projects through a slot i formed in the outer end of the bolster and it also extends through a bearing block generally indicated at 5, the hanger block being secured to the bearing block 5 by means of a pair of pins or bolts 6 extending longitudinally therethrough. The bearing block engages the underside of a pair of lugs 'l'l formed on opposite sides of the slot Q and a row of anti-friction ball bearings 3 is placed on opposite sides of the bearing block, being retained by grooves formed therein. The ball bearings are thus interposed between the lugs l and the bearing block and an anti-friction connection is made which permits lateral movement of the bolster to a limited extent. The coil springs D are sufficiently resilient to permit this lateral movement.

The bolster suspended as shown is hung from the semi-elliptical spring F and it is at the same time supported by the helical springs D. The loads imposed are thus proportionately supported by both sets of springs and as the springs are of a different character and type they will obviously have different periods of vibration, hence counteracting each other and smoothing out periodic vibrations and oscillations which would otherwise be set up. The ends of the bolster are guided with relation to the truck frame A in the usual manner; that is, guideways iii are provided and lugs II are formed on opposite sides thereof to limit endwise movement of the bolster with relation to the frame. A certain amount of play is, however, provided between the lugs and the guides ID, as shown at l2 in Fig. 3. hence permitting a certain amount of floating of the bolster on the ball bearings so as to absorb sudden shocks when the bolster is subjected to longitudinal thrust, the

spring with a corresponding relieving of the helical springs with the result that the relieving of the helical springs by the leaf spring will have a tendency to prevent the helical springs from being forced to their critical point of periodicity with the vibration set up by the load at certain speeds. Furthermore, rebound action of both sets of springs will be materially reduced as a great proportion of the energy liberated by the leaf spring is absorbed by friction between the leaves of the semi-elliptical spring. I have furthermore provided a spring suspension whereby the load can be carried in its entirety in case of accident or breakage of the helical springs.

While certain features of the present invention are more or less specifically described, I wish it understood that various changes may be resorted to within the scope of the appended claims. Similarly, that the materials and finish of the several parts employed may be such as the manufacturer may decide, or varying conditions or uses may demand.

Having thus described my invention, what I claim and desire to secure by Letters Patent is- 1. The combination with a frame of a car truck and a bolster vertically movable therein, of a leaf spring in the frame, a hanger carried by the leaf spring, a connection between the hanger and the bolster whereby weight applied to the bolster is imposed on the leaf spring, and a helical spring interposed between the under side of the bolster and the frame and cooperating with the leaf spring to support any load applied to the bolster.

2. The combination with a frame of a car truck and a bolster vertically movable therein, of a semi-elliptical spring disposed in the frame above the bolster, a shackle connection between each end of said spring and the frame, a hanger forming a connection between the center of said spring and the bolster, and a plurality of helical springs disposed in the frame below the bolster and engaging the underside of the bolster.

3. The combination with a frame of a car truck and a bolster vertically movable therein, of a leaf spring in the frame, a hanger carried by the leaf spring, a hanger frame forming a connection between the hanger and the bolster, and anti-friction means interposed between the hanger frame and the bolster to permit limited endwise floating movement of the bolster.

4. The combination with a frame of a car truck and a bolster vertically movable therein, of a leaf spring in the frame, a hanger carried by the leaf spring, a hanger frame forming a connection between the hanger and the bolster, anti-friction means interposed between the hanger frame and the bolster to permit limited endwise floating movement of the bolster, and means limiting said endwise floating movement of the bolster.

5. The combination with a main frame of a car truck and a bolster vertically movable therein, said bolster having a recess formed in one end and a pair of projecting lugs, a semi-elliptical spring disposed in the frame above the bolster, a hanger block secured to the center portion of said spring and projecting downwardly through the lugs on the bolster into the recess formed therein, a hanger frame secured to the lower end of the hanger block and disposed within the recess in the bolster, and anti-friction bearings carried by the hanger frame and engaging the underside of the lugs.

6. The combination with a main frame of a car truck and a bolster vertically movable therein, said bolster having a recess formed in one end and a pair of projecting lugs, a semi-elliptical spring disposed in the frame above the bolster, a hanger block secured to the center portion of said spring and projecting downwardly through the lugs on the bolster into the recess formed therein, a hanger frame secured to the lower end of the hanger block and disposed within the recess in the bolster, anti-friction bearings carried by the hanger frame and engaging the underside of the lugs, said ball bearings permitting endwise floating movement of the bolster with relation to the hanger block and hanger frame, and means for limiting said endwise floating movement.

'7. The combination with a main frame of a car truck and a bolster vertically movable therein, said bolster having a recess formed in one end and a pair of projecting lugs, a semi-elliptical spring disposed in the frame above the bolster, a hanger block secured to the center portion of said spring and projecting downwardly through the lugs on the bolster into the recess formed therein, a hanger frame secured to the lower end of the hanger block and disposed within the recess in the bolster, anti-friction bearings carried by the hanger frame and engaging the underside of the lugs, and a plurality of helical springs interposed between the lower part of the frame and the underside of the bolster, said helical springs, together with the semi-elliptic spring, forming a resilient support for the bolster with relation to the frame.

8. In combination with a car truck comprising a frame, a bolster, means guiding the bolster for vertical sliding movement in the frame, a leaf spring supported in the frame above the bolster, means connecting the leaf spring and the bolster, and coil springs interposed between the lower side of the bolster and the frame whereby both the leaf spring and coil springs will oppose vertical movement of the bolster.

9. In combination with a car truck comprising a hollow frame, a bolster vertically movable in the frame, a leaf spring disposed between the side walls of said hollow frame, a pair of shackles connecting the ends of the spring to the frame, and means connecting said leaf spring with the bolster.

10. In combination with a car truck comprising a hollow frame, a bolster vertically movable in the frame, a leaf spring disposed between the side walls of said hollow frame above the bolster, a hanger block surrounding the spring and supporting means for connecting said leaf spring with the bolster, and anti-friction means between the bolster and said connecting means to permit limited floating movement of the bolster.

11. In combination with a car truck comprising a frame, a bolster extending into the frame and movable vertically therein, a leaf spring carried by the frame and extending over the bolster, means connecting the leaf spring with the bolster, and a coil spring between the bottom of the bolster and the frame.

WILLIAM R. HEWITT.

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