Background of the Invention
Heretofore there have been trucks having independently movable side frames, air springs supporting a car body on a bolster, a bolster turnably supported on side frames, said wheel-axle units having resilient bearing connections with the side frames.
One such truck having these characteristics was the "Pioneer" truck, U.S. Pat. No. 2,908,230, which, in various models, has such characteristics and has been extensively used for many years in both local and main line operation and has given economical and safe service over long periods of time with minimal attention.
Also there have been trucks having transom bars rigid with one side frame and having joint connections with the other side frame which provide universal movements, as through elastomeric connections or ball joints. For example, see U.S. Pat. No. 2,879,718.
However, so far as known, there have been no trucks of this type which provided the improvement in ride performance and control secured by the present invention. In particular, as a detail, the universal joints of the transom bars did not give positive control of truck tram.
Summary of Invention
The present invention aims to improve on former truck designs to provide a light weight truck having a new and improved organization which will give a smoother and better controlled ride with more accurate control of all relative movements of parts in the simple truck frame, and, when the axles are power driven, to closely control the movements of the motor-drive frame. The details of these improvements will be apparent as the description proceeds.
Drawings
The objects and advantages of the invention, as well as various features of novelty, will be apparent from the following description of an exemplary embodiment thereof, reference being made to the accompanying drawings, wherein:
FIG. 1 is a prospective view of a railway truck embodying the present invention;
FIG. 2 is a top plan view of a railway vehicle truck embodying the invention;
FIG. 3 is a side view of the truck;
FIG. 4 is a transverse vertical view partially in section taken on the line 4--4 of FIG. 2;
FIG. 5 is a longitudinal vertical view partially in section taken on the line 5--5 of FIG. 2;
FIG. 6 is an end elevational view of the truck;
FIG. 7 is a partial vertical transverse section taken on the line 7--7 of FIG. 3, showing axle-to-side-frame connection;
FIG. 8 is a partial horizontal section taken on the line 8--8 of FIG. 6, showing axle drive means;
FIG. 9 is a longitudinal vertical view partially in section taken on the line 9--9 of FIG. 4, showing safety support arrangements for the truck bolster.
Specific Embodiment
As shown, the truck comprises two separate independently movable side frames 20 of hollow rigid construction connected at the ends of resilient bearing joints 22, as including elastomeric material 22a, (FIG. 7) with wheel-axle units 23 (wheels 23a and axles 23b), these joint connections allowing universal turning movement about three coordinate axes but inhibiting or substantially preventing axial or transverse movement. These joint connections hold the side frames at a fixed distance apart.
The side frames are positively held together in tram, but with free weaving movement, by strong rigid transverse transom bars 25 located at suitable distances fore and aft of a central transverse vertical plane of the truck. One end of each transom bar is made rigidly integral with a side frame 20, as by welding, and the other end is formed as a journal or shaft 27 which is rotatably mounted in a bearing 28 of the opposite side frame.
The transom bars are reversely mounted, one being rigidly secured to the side frame on which the other transom bar has a bearing connection. It is to be noted that the journals 27 are axially aligned with each other along a line L passing through the central vertical turning axis of the truck. Due to the location of the journal bearing joints in a convenient location on top of the side frames and above the horizontal plane of the wheel-axle bearings, the journals will have some axial sliding movement in their bearings as the side frames weave relative to each other but will retain their status as true shaft-bearing joints, no resilient elements or ball joints being involved. Consequently the transom bars strongly maintain the squareness or tram of the truck. Caps 27a are secured to the outer ends of the journals, as by cap screws, to prevent separation at the bearings under extreme conditions, such as a collision or lift of the truck with the vehicle. The line L of the axis of the transom bar journals may have different positions relative to the central transverse vertical plane, the position here shown being about 30.degree. .
The transom bars, having true shaft bearings, provide positive means for maintaining the truck squareness or tram while allowing the required weave of the side frames. Universal joints, such as ball joints or elastomeric supports do not provide such positive control of tram.
A center plate or frame 30 is supported on the transom bars 25, having transversely central longitudinal projections 31 positioned above the transom bars (above for fail safe) and connected to the transom bars by suitable joints including resilient elements 32 and retaining pins 33. The resilient elements are wide and thin and provide ample turning movements in vertical planes but allow but little direct vertical movement. The transverse central position of these joints minimizes relative turning movement and vertical movement tendency. The longitudinal position shown is approximately on or near a transverse vertical plane which passes through a journal 27 about mid-length in its bearing.
The center frame 30 has a center king post connection with a truck bolster 35, here the center frame having a large upstanding tubular center king pin or post 36 disposed within a center bearing 37 of the bolster. The center pin is retained by a cap 38 held by screws 39. A friction-reducing sleeve 40 is disposed between the pin or post and the bearing. This may be a known plastic-graphite element, as with teflon, or the like. It provides a slight resiliency but the connection is still essentially a true shaft-bearing joint and maintains the parts in definite relative position. Some prior trucks have had center connections with considerable loose movement or wobble and have been hard to control and subject to undue wear.
The truck bolster 35 is turnably supported on the side frames 20. The side frames have bearing surfaces or plates 45 and the truck bolster has pads or shoes 46 backed by resilient elements 47, height adjusting shims 48 being interposed between the pads and the resilient elements.
The bolster 35, above the side frame bearing support, is provided with spring means S supporting a vehicle or car body, the spring means here employed being air spring units having the upper end S1 connected to the vehicle body and the lower end S2 connected to the bolster. An interior elastomeric stop member S3 limits maximum vertical movement to provide an acceptable failsafe ride.
The truck bolster 35 is held in proper longitudinal position relative to the vehicle body by longitudinal stay bars 50, connected by flexible joints to brackets 51 secured to the vehicle body and by flexible joints to brackets 52 carried by downturned portions 53 of the truck bolster. These flexible joints, of known type, as of elastomeric material, permit all necessary vertical movements of the truck bolster and such lateral movements as are permitted.
Lateral movement of the truck bolster is damped by shock absorbers 55 operated by links 56 connected to supports 57 depending from the vehicle body. Maximum lateral movement is limited by elastomeric bumpers 58 carried by side brackets 58a, secured, as by welding, to the bolster, the bumpers engaging brackets 59 depending from the vehicle body.
The brackets 58 also carry a vertically adjustable safety strap 61 which will support the truck transom, and through connections, support the truck in case the truck is lifted with or tends to separate from the vehicle body. FIG. 8 shows how the support members 57 may be exchanged as between shallow (left) and deep (right) members to fit the dimensional needs of the vehicle and truck.
The center frame 30, at the sides, carries depending support portions 65 on which, by resilient joints 66 and connecting bolts 67, is carried a rigid motor and gear box frame or casing 68 supporting a centrally disposed motor M and having longitudinally extending portions 69 with lateral extensions 70 at the axles for driving the axles while permitting free weaving movement between the axles and frame or casing. FIG. 8 shows the drive connection at the axle in detail. A ring gear sleeve 71 loosely surrounds the axle and drives it through a flexible connection 72 at one end.
The truck bolster 35 at the sides near the air springs S has secured thereon, as by welded brackets R1, air reservoirs R which have suitable flow connections with the air springs to aid the spring action control, valves or orifices being provided at suitable locations to adjust the action as desired. It is not considered pertinent to illustrate these connections, valves, orifices and the like since, in general, they are conventional.
The transom bars 25 support brake operating units B which have shoes 75 acting on brake disks 76 carried by the axles 23b of the truck, suitable relative movement of the brake unit being provided in its mounting supports.
The axles 25b also carry electrical brush rings 77 for connection through brushes and conductors (not shown) with the drive motor to establish a more reliable connection with the rail than would be furnished through the axle connections with the motor conductors. On a powered truck there will be a third rail shoe mount for power connections but it is not necessary to show this.
An anti-roll torque bar suspension 80 extends across the truck, being mounted in bearings 81 carried by the vehicle body and is connected with opposite ends of the truck bolster by arms 82 and links 83, with suitable pivot connections at the arm ends and brackets 84 carried by the bolster.
It is thus seen that the invention provides a new and improved truck assembly which gives more precise control of relative movements of parts. The true shaft-bearing joints of the transom bars on the side frames provide all needed relative weaving movements of the side frames and provide positive tram control which could not be obtained by joints having universal movement, as ball joints or elastomeric connections.
The provision of the center plate mounted on laterally central resilient supports on the transom bars allows the bolster to have a king pin joint with true shaft-bearing joint movement. The center plate also furnishes a suitable support for the motor drive frame so that it can have its required operative position and flexible drive of the axles. The arrangement places the spring support of the vehicle on the bolster directly above the side frames and provision of resiliently backed turning pads on the bolster provides better control of movements and better protection of parts.
This truck system provides a plurality of suspension elements or points wherein each performs its function independently of the others and is subject to separate and independent design and control. There are two vertical suspension elements, the wheel-axle connection and the air spring connections. And there are two lateral suspension elements or points, the pull connection through the bolster center pin and the transverse connection through the torque bar. While one embodiment of the invention has been described for purposes of illustration, it is to be understood that there may be various embodiments and modifications within the general scope of the invention.