CA1054858A - Reinforced boister - Google Patents
Reinforced boisterInfo
- Publication number
- CA1054858A CA1054858A CA277,229A CA277229A CA1054858A CA 1054858 A CA1054858 A CA 1054858A CA 277229 A CA277229 A CA 277229A CA 1054858 A CA1054858 A CA 1054858A
- Authority
- CA
- Canada
- Prior art keywords
- rib
- bolster
- reinforcing means
- further characterized
- reinforcing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61F—RAIL VEHICLE SUSPENSIONS, e.g. UNDERFRAMES, BOGIES OR ARRANGEMENTS OF WHEEL AXLES; RAIL VEHICLES FOR USE ON TRACKS OF DIFFERENT WIDTH; PREVENTING DERAILING OF RAIL VEHICLES; WHEEL GUARDS, OBSTRUCTION REMOVERS OR THE LIKE FOR RAIL VEHICLES
- B61F5/00—Constructional details of bogies; Connections between bogies and vehicle underframes; Arrangements or devices for adjusting or allowing self-adjustment of wheel axles or bogies when rounding curves
- B61F5/50—Other details
- B61F5/52—Bogie frames
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61F—RAIL VEHICLE SUSPENSIONS, e.g. UNDERFRAMES, BOGIES OR ARRANGEMENTS OF WHEEL AXLES; RAIL VEHICLES FOR USE ON TRACKS OF DIFFERENT WIDTH; PREVENTING DERAILING OF RAIL VEHICLES; WHEEL GUARDS, OBSTRUCTION REMOVERS OR THE LIKE FOR RAIL VEHICLES
- B61F5/00—Constructional details of bogies; Connections between bogies and vehicle underframes; Arrangements or devices for adjusting or allowing self-adjustment of wheel axles or bogies when rounding curves
- B61F5/02—Arrangements permitting limited transverse relative movements between vehicle underframe or bolster and bogie; Connections between underframes and bogies
- B61F5/04—Bolster supports or mountings
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Body Structure For Vehicles (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A railroad car truck bolster has a centrally dis-posed vertically arranged longitudinally extending rib.
The rib has spaced reinforcing means with the spacing of the reinforcing means being sufficient such that certain fractures in the rib propagating along lines of maximum shear stress at approximately 45 degrees to lines of prin-cipal stress will reach a reinforcing means at a point closer to the neutral axis of the rib than the next adjacent external surface of the rib.
A railroad car truck bolster has a centrally dis-posed vertically arranged longitudinally extending rib.
The rib has spaced reinforcing means with the spacing of the reinforcing means being sufficient such that certain fractures in the rib propagating along lines of maximum shear stress at approximately 45 degrees to lines of prin-cipal stress will reach a reinforcing means at a point closer to the neutral axis of the rib than the next adjacent external surface of the rib.
Description
1~54858 The present invention relates to railroad car truck bolsters and in particular to means for reinforcing a bolster center rib.
Certain design changes in the side walls of a cast bolster, particularly the addition of openings, re-quires that strengthening means be added elsewhere in the bolster. In the present application such a strengthening means is provided by a centrally disposed rib. As the bolster is a critical part of a car truck, it is necessary to reinforce the bolster rib to insure that it will not fracture in a manner to result in complete failure. In the present application the bolster has been reinforced by the addition of transversely disposed reinforcing ribs which are so positioned as to prevent fractures in the rib from propagating from one surface of the central rib to the opposite external surface.
A primary purpose of the invention is a bolster having reinforcing areas along a centrally disposed rib, which reinforcing areas prevent fractures in the rib from propagation from one surface to the other opposite external surface.
Another purpose is a bolster of the type described in which a centrally disposed rib, discontinuous at the center of the bolster, has a series of laterally extending reinforcing ribs.
Another purpose is an economical and reliable as cast strengthened bolster.
Other purposes will appear in the ensuing specifica-tion, drawings and claims.
1~548S8 BRIEF DESCRIPTION OF THE DRAWINGS
The invention is illustrated diagrammatically in thefollowing drawings wherein: `
Figure 1 is a side view, in part section, illustrating the bolster, Figure 2 is a top plan view of the bolster, Figure 3 is a section along plane 3-3 of Figure 1, Figure 4 is a section along plane 4-4 of Figure 1, and Figure 5 is a diagrammatic illustration of the lines o principal stress applied to the bolster rib under certain load conditions.
1~54858 DESCRIPTION OF THE PREFERRED EMBODIMENT
Only the car truck bolster itself is shown and described herein. It will be understood by those skilled in the art that the bolster is customarily supported on springs mounted on side frames with the center hub of the bolster supporting the car body.
In the drawings, the bolster has a top 10, a bottom 12, and side walls 14 and 16. A female center plate 18 extends upwardly from top 10 as is conventional. Side walls 14 and 16 each have a pair of spaced enlarged openings 20 which permit cross anchor rods to extend through the bolster, such rods being attached at their opposite ends, to the bearings supporting the side frames on the axles. Opposite ends of the bolster bottom 12 may have conventional spring bosses 22 which are used to anchor the upper end of the springs which support the bolster on the side frames.
A generally centrally disposed vertically extend-ing rib 24 extends from opposite ends of the bolster toward the center with the rib being discontinuous in the area beneath female center plate 18. In effect, there are rib sections 26 and 28 on opposite sides of the bolster center plate.
In the area between rib sections 26 and 28 there is a lateral center wall 30 extending between top 10 and bottom 12. There is a central opening 32 in wall 30 to permit the passage of the above-described rods. Directly below opening 32 and extending over the length of the rib disc:ontinuity there are internal lateral walls 36 and 38 which form the ends of box 34 and extend between top 10 and bottom 12. Each wall 36 and 38 has a centrally extending fillet, 40 and 42, respectively, with openings 40a and 40b and 42a and 42b being on opposite sides of the fillets to permit the passage of the above-described rods.
Bolster rib sections 26 and G~ each has a plurality, in this case three, laterally extending reinforcing ribs, extending from each side of the bolster rib and designated as 26a, 26b, and 26c and 28a, 28b, and 2~c. The reinforcing ribs ~r reinforcing areas or reinforcing means are specifically and particularly located as will appear hereinafter. The reinforcing means may take various forms, and the ribs shown herein are only one such means.
The use of openings 20 in the side walls of the bolster 1~ ~equires the addition of s~rengthening means. Rib sections 26 and ~8 provide the necessary protection. However, as a bolster is a most critical portion of the car truck and a complete fracture of the bolster rib would most likely result in the complete failure of the bolster, which in turn would cause derailment of the freight car, it is necessary that the bolster ribs be reinforced.
5tructures formed of ductile metals, such as, steel, which generally have equal properties in all directions, initially contain microscopic flaws. As the component is subjected to a time varying load, a typical flaw will increase in size. As the flaw growth increases the strength of the component naturally decreases. As railroad freight car truck components, and more particularly the bolster, most likely will have infrequent inspections, and as there is a possibility that a flaw would not be detected during such an inspection, the bolster must be designed so that flaw growth is contained and t~e structure retains its required designed strength. Ribs 26a, 26b, and 26c and 28a, 28b, and 28c are specifically designed to accomplish this end.
It i5 known that the stress most likely to lead to failure in ductile materials is shear stress. Of the many theories that have attempted to describe the mechanics of material failure, the maximum shear theory has the most practical application to the present type of structure. This theory provides that the maximum shear stress will occur on a line forming a 45-(psi X 1, 000) degree angle with a line of principal stres~. Figure 5 shows lines of principal stress in rib sections 26 and 28 for the par-ticular type of load which would supply the severest test of ~he rib component. The lines of greatest stress are at the bottom of the rib with the amount of principal stress gradually decreas-ing toward the top of the rib section. Applying the maximum shear theory, the line upon which a failure due to a microscopic flaw will propagate will be at 45 degrees to a line of principal stress.
Although the lines of principal stress are not parallel, they are similar and thus in general the lines of fracture or failure propagation will be at 45 degrees or approximately so to all such lines to principal stress. The ribs or reinforcing areas ~6a, 2 6b and 26c, and 28a, 28b and 28c, ar~ placed such that certain lines of fracture propagation will meet the reinforcing rib at a point closer to the neutral axis of the rib than the next external surface, which normally would be the top surface of the rib. The-neutral axis is approximately at the mid-point of the rib, although this will vary, depending upon construction peculiarities. Thus, it is desired that the lines of fracture from flaws near the bottom of the rib, which are the flaws which will be under the greatest stress and therefore the flaws most likely to increase or propagate along the described shear stress lines, meet a reinforcing area at a point less than 75% of the full height of the rib. The reinforcing means, or reinforcing areas or vertical reinforcing ribs, are effective to prevent further propagation of the described failures or fractures.
Horizontal reinforcing means would not stiffen rib sections 26 and 28 and thus would not be effective for the intended purpose.
As can be noted from the stress diagram, Figure 5, the values of the lines of principal stress are substantially lower ' -6-- ~054858 in the top area of the rib than in the bottom area. Thus, fractures caused by flaws in these areas are not of substantial concern as there is normally not sufficient stress applied to that portion of the component to cause propagation of the flaw alonc3 the described fracture line. Thus, the reinforcing means are placed so as to prevent flaws in the lower portion of the rib propagating along the described fracture lines from meeting an external surface, normally the top of the rib. The stress applied to the lower portions of the rib are those which are the highest and thus flaws in the lower portion of the rib are those which must be contained.
The ribs are spaced apart a distance so as to prevent the described flaws from propagating closer to an external surface than to the neutral axis which is generally the mid-point of the rib. Although it might be an ideal solution to put many more ribs than those shown, the difficulties in casting the bolster would then become insurmountable. The ribs are preferably spaced apart as great a distance as possible, consistent with the described shear theory, so as to reduce the ribs to a number which can be economically and practically cored and cast.
Whereas th~ preferred form of the invention has been shown and described herein, it should be realized that there may be many modifications, substitutions, and alterations thereto.
Certain design changes in the side walls of a cast bolster, particularly the addition of openings, re-quires that strengthening means be added elsewhere in the bolster. In the present application such a strengthening means is provided by a centrally disposed rib. As the bolster is a critical part of a car truck, it is necessary to reinforce the bolster rib to insure that it will not fracture in a manner to result in complete failure. In the present application the bolster has been reinforced by the addition of transversely disposed reinforcing ribs which are so positioned as to prevent fractures in the rib from propagating from one surface of the central rib to the opposite external surface.
A primary purpose of the invention is a bolster having reinforcing areas along a centrally disposed rib, which reinforcing areas prevent fractures in the rib from propagation from one surface to the other opposite external surface.
Another purpose is a bolster of the type described in which a centrally disposed rib, discontinuous at the center of the bolster, has a series of laterally extending reinforcing ribs.
Another purpose is an economical and reliable as cast strengthened bolster.
Other purposes will appear in the ensuing specifica-tion, drawings and claims.
1~548S8 BRIEF DESCRIPTION OF THE DRAWINGS
The invention is illustrated diagrammatically in thefollowing drawings wherein: `
Figure 1 is a side view, in part section, illustrating the bolster, Figure 2 is a top plan view of the bolster, Figure 3 is a section along plane 3-3 of Figure 1, Figure 4 is a section along plane 4-4 of Figure 1, and Figure 5 is a diagrammatic illustration of the lines o principal stress applied to the bolster rib under certain load conditions.
1~54858 DESCRIPTION OF THE PREFERRED EMBODIMENT
Only the car truck bolster itself is shown and described herein. It will be understood by those skilled in the art that the bolster is customarily supported on springs mounted on side frames with the center hub of the bolster supporting the car body.
In the drawings, the bolster has a top 10, a bottom 12, and side walls 14 and 16. A female center plate 18 extends upwardly from top 10 as is conventional. Side walls 14 and 16 each have a pair of spaced enlarged openings 20 which permit cross anchor rods to extend through the bolster, such rods being attached at their opposite ends, to the bearings supporting the side frames on the axles. Opposite ends of the bolster bottom 12 may have conventional spring bosses 22 which are used to anchor the upper end of the springs which support the bolster on the side frames.
A generally centrally disposed vertically extend-ing rib 24 extends from opposite ends of the bolster toward the center with the rib being discontinuous in the area beneath female center plate 18. In effect, there are rib sections 26 and 28 on opposite sides of the bolster center plate.
In the area between rib sections 26 and 28 there is a lateral center wall 30 extending between top 10 and bottom 12. There is a central opening 32 in wall 30 to permit the passage of the above-described rods. Directly below opening 32 and extending over the length of the rib disc:ontinuity there are internal lateral walls 36 and 38 which form the ends of box 34 and extend between top 10 and bottom 12. Each wall 36 and 38 has a centrally extending fillet, 40 and 42, respectively, with openings 40a and 40b and 42a and 42b being on opposite sides of the fillets to permit the passage of the above-described rods.
Bolster rib sections 26 and G~ each has a plurality, in this case three, laterally extending reinforcing ribs, extending from each side of the bolster rib and designated as 26a, 26b, and 26c and 28a, 28b, and 2~c. The reinforcing ribs ~r reinforcing areas or reinforcing means are specifically and particularly located as will appear hereinafter. The reinforcing means may take various forms, and the ribs shown herein are only one such means.
The use of openings 20 in the side walls of the bolster 1~ ~equires the addition of s~rengthening means. Rib sections 26 and ~8 provide the necessary protection. However, as a bolster is a most critical portion of the car truck and a complete fracture of the bolster rib would most likely result in the complete failure of the bolster, which in turn would cause derailment of the freight car, it is necessary that the bolster ribs be reinforced.
5tructures formed of ductile metals, such as, steel, which generally have equal properties in all directions, initially contain microscopic flaws. As the component is subjected to a time varying load, a typical flaw will increase in size. As the flaw growth increases the strength of the component naturally decreases. As railroad freight car truck components, and more particularly the bolster, most likely will have infrequent inspections, and as there is a possibility that a flaw would not be detected during such an inspection, the bolster must be designed so that flaw growth is contained and t~e structure retains its required designed strength. Ribs 26a, 26b, and 26c and 28a, 28b, and 28c are specifically designed to accomplish this end.
It i5 known that the stress most likely to lead to failure in ductile materials is shear stress. Of the many theories that have attempted to describe the mechanics of material failure, the maximum shear theory has the most practical application to the present type of structure. This theory provides that the maximum shear stress will occur on a line forming a 45-(psi X 1, 000) degree angle with a line of principal stres~. Figure 5 shows lines of principal stress in rib sections 26 and 28 for the par-ticular type of load which would supply the severest test of ~he rib component. The lines of greatest stress are at the bottom of the rib with the amount of principal stress gradually decreas-ing toward the top of the rib section. Applying the maximum shear theory, the line upon which a failure due to a microscopic flaw will propagate will be at 45 degrees to a line of principal stress.
Although the lines of principal stress are not parallel, they are similar and thus in general the lines of fracture or failure propagation will be at 45 degrees or approximately so to all such lines to principal stress. The ribs or reinforcing areas ~6a, 2 6b and 26c, and 28a, 28b and 28c, ar~ placed such that certain lines of fracture propagation will meet the reinforcing rib at a point closer to the neutral axis of the rib than the next external surface, which normally would be the top surface of the rib. The-neutral axis is approximately at the mid-point of the rib, although this will vary, depending upon construction peculiarities. Thus, it is desired that the lines of fracture from flaws near the bottom of the rib, which are the flaws which will be under the greatest stress and therefore the flaws most likely to increase or propagate along the described shear stress lines, meet a reinforcing area at a point less than 75% of the full height of the rib. The reinforcing means, or reinforcing areas or vertical reinforcing ribs, are effective to prevent further propagation of the described failures or fractures.
Horizontal reinforcing means would not stiffen rib sections 26 and 28 and thus would not be effective for the intended purpose.
As can be noted from the stress diagram, Figure 5, the values of the lines of principal stress are substantially lower ' -6-- ~054858 in the top area of the rib than in the bottom area. Thus, fractures caused by flaws in these areas are not of substantial concern as there is normally not sufficient stress applied to that portion of the component to cause propagation of the flaw alonc3 the described fracture line. Thus, the reinforcing means are placed so as to prevent flaws in the lower portion of the rib propagating along the described fracture lines from meeting an external surface, normally the top of the rib. The stress applied to the lower portions of the rib are those which are the highest and thus flaws in the lower portion of the rib are those which must be contained.
The ribs are spaced apart a distance so as to prevent the described flaws from propagating closer to an external surface than to the neutral axis which is generally the mid-point of the rib. Although it might be an ideal solution to put many more ribs than those shown, the difficulties in casting the bolster would then become insurmountable. The ribs are preferably spaced apart as great a distance as possible, consistent with the described shear theory, so as to reduce the ribs to a number which can be economically and practically cored and cast.
Whereas th~ preferred form of the invention has been shown and described herein, it should be realized that there may be many modifications, substitutions, and alterations thereto.
Claims (7)
1. In a railroad car truck bolster, a top surface, a bottom surface, and side walls, a generally centrally disposed vertical rib extending between said top and bottom surface, and a plurality of generally vertically arranged spaced reinforcing means integral with said rib;
said integral reinforcing means being spaced apart a horizontal distance sufficient to cause certain fractures in the rib propagating along lines of maximum shear stress at approximately 45 degrees to lines of principle stress to reach a reinforcing means at a point closer to the neutral axis of the rib than the next adjacent external surface of the rib.
said integral reinforcing means being spaced apart a horizontal distance sufficient to cause certain fractures in the rib propagating along lines of maximum shear stress at approximately 45 degrees to lines of principle stress to reach a reinforcing means at a point closer to the neutral axis of the rib than the next adjacent external surface of the rib.
2. The bolster of Claim 1 further characterized in that said reinforcing means extend outwardly from opposite sides of said rib.
3. The bolster of Claim 2 further characterized in that said reinforcing means extending from opposite sides of said rib, are in alignment.
4. The bolster of Claim 1 further characterized in that said reinforcing means include laterally and vertically extending reinforcing ribs.
5. The bolster of Claim 1 further characterized in that said rib is discontinuous in a generally central area of said bolster.
6. The bolster of Claim 5 further characterized by and including a pair of spaced vertically extending members extending between and throughout the discontinuous area of said rib.
7. The bolster of Claim 1 further characterized by and including openings in each of said side walls on opposite sides of the bolster vertical center line.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US76602277A | 1977-02-07 | 1977-02-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1054858A true CA1054858A (en) | 1979-05-22 |
Family
ID=25075161
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA277,229A Expired CA1054858A (en) | 1977-02-07 | 1977-04-28 | Reinforced boister |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS5398614A (en) |
| AU (1) | AU504702B2 (en) |
| BR (1) | BR7705382A (en) |
| CA (1) | CA1054858A (en) |
| FR (1) | FR2379414A1 (en) |
| IN (1) | IN148210B (en) |
| MX (1) | MX144120A (en) |
| ZA (1) | ZA772291B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2319819C (en) * | 1998-01-30 | 2007-03-27 | Buckeye Steel Castings Company | Lightweight truck bolster |
-
1977
- 1977-04-14 ZA ZA00772291A patent/ZA772291B/en unknown
- 1977-04-20 AU AU24450/77A patent/AU504702B2/en not_active Expired
- 1977-04-28 CA CA277,229A patent/CA1054858A/en not_active Expired
- 1977-05-09 JP JP5216077A patent/JPS5398614A/en active Granted
- 1977-05-16 FR FR7714992A patent/FR2379414A1/en active Granted
- 1977-05-31 MX MX169261A patent/MX144120A/en unknown
- 1977-08-15 BR BR7705382A patent/BR7705382A/en unknown
- 1977-12-01 IN IN1673/CAL/77A patent/IN148210B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| ZA772291B (en) | 1978-03-29 |
| MX144120A (en) | 1981-08-27 |
| JPS5398614A (en) | 1978-08-29 |
| AU504702B2 (en) | 1979-10-25 |
| FR2379414A1 (en) | 1978-09-01 |
| JPS5760182B2 (en) | 1982-12-18 |
| IN148210B (en) | 1980-12-06 |
| AU2445077A (en) | 1978-10-26 |
| BR7705382A (en) | 1978-09-12 |
| FR2379414B1 (en) | 1982-10-22 |
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