Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3824868 A
Publication typeGrant
Publication dateJul 23, 1974
Filing dateMay 7, 1973
Priority dateMay 7, 1973
Also published asCA987255A1
Publication numberUS 3824868 A, US 3824868A, US-A-3824868, US3824868 A, US3824868A
InventorsFahrenwald F
Original AssigneeFahralloy Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
High temperature belt link construction
US 3824868 A
Abstract
A high temperature conveyor belt, and a belt link for use therein, of the type used in heat treat furnaces in which excessive deformation of the link, with consequent interference in flexing action, and premature failure due to shrinkage defects is substantially eliminated by use of a protuberance within the link which limits link deformation and ensures internally sound metal.
Images(2)
Previous page
Next page
Description  (OCR text may contain errors)

United States Patent [191 Fahrenwald [111 3,824,868 1451 July 23, 1974 HIGH TEMPERATURE BELT LINK CONSTRUCTION [75] Inventor: Francis M. Fahrenwald, Chicago,

Ill.

[73] Assignee: The Fahralloy Company, Harvey, [11.

[22] Filed: .May 7, 1973 [21] App]. No.1 357,546

[52] US. Cl. 74/235 [51] Int. Cl. F16g 12/40 [58] Field of Search 74/235, 250 R, 250 C I [56] References Cited UNITED STATES PATENTS 1,243,537 1 10/1917 Lynn ,L 74/235 Matsumoto 74/235 6/1927 Cavanaugh 74/235 1,631,580 1,907,636 5/1933 Woodman 74/235 2,229,106 l/l94l Lomando 74/250 R- Primary Examiner-Leonard l-I. Gerin Attorney, Agent, or Firm-James G. Staples 57 ABSTRACT A high temperature conveyor belt, and a belt link for use therein, of the type used in heat treat furnaces in which excessive deformation of the link, with consequent interference in flexing action, and premature failure due to shrinkage defects is substantially eliminated by use of a protuberance within the link which limits link deformation and ensures internally sound metal.

14 Claims, 10Drawing Figures HIGH TEMPERATURE BELT LINK CONSTRUCTION BACKGROUND OF TI-IEINVENTION This invention relates to an improved cast part which is utilized under high temperature and high stress conditions, and specifically to a high temperature con veyor belt, and a link therefor, of the type used in heat treat urnaces-.7, A conveyor belt link widely used in heat treat furnaces today generally includes an elongated, open interior formed by two straps, an upper strap portion and a lower strap portion, which are joined at their ends by arcuate end or journal portions. Generally the upper strap portion has an expanded mid portion. The links are so constructed and arranged that by interfitting one with another a substantially flat load carrying area is provided. The interfitted links are secured one to another by pins passing through overlapped ends of adjacent links. The pins provide flexibility to the moving platform formed by the links as they traverse first a planar section through the furnace and then an arcuate section during their passage along an endless, orbital path. V

A problem of particular concern to the manufacturer and user of such heat treat furnace conveyors is the tendency of the belt links to deform in use, sin such conveyors are oftensubjected to temperatures in the range of l650-l800F while carrying substantial loads. It will be understood that at these temperatures the individual links are semi-plastic. Excessive bowing or bending can seriously interfere with the operation of the conveyor since the deformation can be so great as to pinch the connecting pins which join one link to another and thereby interfere with the action of the conveyor.

A common way of strengthening the link to avoid this problem is to connect the top and bottom strap portions by an integrally cast post. However, in the casting process a shrinkage void tends to form at the junctures of the post and straps.

As those skilled in the art appreciate, shrinkage within a casting such as the above described link is a highly undesirable condition. The shrinkage results from the fact that the metal in the shrinkage zone is the last to freeze, and, during the shrinkage process, a void results. The shrinkage void is an undesirable condition since first, the metal surrounding the shrinkage zone has a different, and generally'inferior, chemistry than the first frozen metal and, secondly, the metal in the shrinkage zone consists of dendritic needles, the intersection of which form excellent stress raisers. As a consequence the foundryman seeks to eliminate orat least minimize shrinkage wherever possiblexl-lowever, to the present time, belt links of the type above described .have, almost invariably, included undesirable shrinkage.

SUMMARY OF THE INVENTION Accordingly, a primary object of the invention is to provide a high temperature conveyor belt, and a con veyorbelt link for use therein, which overcomes the deficiencies of structurescurrently in use.

Another object is to providefahigh'temperature conveyor belt link in which shrinkage flaws are eliminated or substantially minimized.

Yet another object is to provide a high temperature conveyor belt link in which the condition of pinching of the connecting pins due to excessive bending or other deformation of the link is precluded.

A further object is to provide a high temperature conveyor belt link as above described in which an effective cleaning action can be imparted to said link as it passes over an end pulley in a conveyor furnace.

Other objects and advantages of the invention will be apparent from reading the following description thereof.

DESCRIPTION OF VIEWS The invention is illustrated more or less diagrammatically in the accompanying Figures wherein:

FIG. 1 is an elevation view. of a high temperature conveyor belt link of the invention;

FIG. 2 is a bottom plan view with a portion broken away of the high temperature conveyor belt link of FIG. 1;

FIG. 3 is a partial view of a high temperature conveyor belt installation, with parts in section and others broken away, illustrating use of a high temperature conveyor belt of the present invention;

FIG. 4 is an elevation view of another embodiment of the high temperature conveyor belt link of the invention;

FIG. 5 is a top plan view of the high temperature conveyor belt link of FIG. 4',

FIG. 6 is a top plan view of a portion of a shell mold layout used in the production of the high temperature conveyor belt link of the invention;

FIG. 7 is an end view with portions of the link and the shell mold omitted for clarity taken substantially along the line 7-7 of FIG. 6;

FIG. 8 is a partial view of a high temperature conveyor belt installation, with parts in section and others broken away, illustrating the high temperature conveyor belt of the present invention;

FIG. 9 is a top view of a prior art link, showing its condition after a period of use; and

FIG. 10 is another view of the prior art link of FIG. 9.

DETAILED DESCRIPTION Like reference numerals will be used to refer to like parts throughout the following description of the Figures.

A high temperature conveyor belt link is indicated generally at 10 in FIGS. 1 and 2. The link includes an upper strap portion 11 and a bottom strap portion 12, the upper and lower strap portions 11 and 12 being connected by generally arcuately shaped end or journal portions 13 and 14.

Upper strap portion 11 includes an expanded mid portion 15 which is slightly upwardly bowed in vertical elevation as best seen in FIG. 1, and generally rectangular in horizontal outline as best seen in FIG. 2. Appropriate edges may be chamfered as desired as indicated at 16, for example.

Connecting pins are indicated generally at 17 and 18. Each pin is arranged to connect a leading link, such as link 10, to a trailing link, suchas link 19, when it is desired to forma conveyor composed of said links, such as an endless, orbitally moveable conveyor belt of the type indicatedat 20 in FIG. 3.

A protuberance 22 extends inwardly from the under surface 23 of upper strap portion 11, as best seen in FIGS. 1 and 2. As best seen from FIG. 1, the protuberance terminates a short distance from the inner surface 25 of lower strap portion 12. In a link having a 4 inch pitch, that is a 4 inch span between the center axes of pins 17 and 18, and a nominal inch spacing between the upper and lower strap portions, the protuberance may extend to within about 4 inch from inner surface 25. As best seen from FIGS. 1 and 2, the protuberance 22 may be described as a round post which terminates short of the opposite strap portion. The protuberance 22 should be of substantial volume and properly located in order to ensure the absence of shrinkage in the upper strap or the protuberance.

One type of conveyor with which the invention may be employed is partially indicated in FIG. 3, the section illustrated being the drive drum 27, which rotates on shaft 28 in the direction indicated by the'arrow. It will be understood that drive drum 27, or at least the right end portion of it, will usually be located at the discharge end of the heat treat furnace. v

The conveyor consists, in this instance, of a large number of individual belt links 10, a, 10b, 10c, 10d, which have been secured one to another by suitable connecting means, such as pins 17, 18. In FIG. 3 the individual belt links are indicated in the position they will assume after long exposure, such as two years or longer, to the high temperature furnace with which they are used; that is, the lower strap portion 12 will have been deformed or bowed inwardly to substantially the' position indicated at 26 in FIG. 1, in which the upper surface 25 of the lower strap portion of the link contacts the lower surface of protuberance 22. If the conveyor belt link is subjected to considerable stress at high temperatures for prolonged periods, there may be some deformation of the upper strap portion of the link to the position indicated at 30. In this event there may be a slightly further deformation of the lower strap portion.

A cleaning mechanism is indicated generally at 31. The cleaning mechanism, here a scraper device, is so positioned that it will yieldably contact and scrape clean the upper load receiving surface of the link after a part which has been supported thereon is discharged, as by gravity, which in this instance will have occurred about the time each link reaches the position of link 10a.

It will be understood that sand, dross, and other particulate matter may accumulate on the carrying surface of the link, and in view of the elevated temperatures to which the links are exposed and the semi-solid condition of both the links and the treated parts due to the elevated temperatures, it is always possible that such v particulate matters may be picked up by subsequently treated parts. j

Another embodiment of the invention is illustrated in FIGS. 4-8.

In this embodiment a high temperature conveyor belt link is indicated generally at '40 in FIGS. 4, 5, and 7. The link includes an upper strap portion 41 and a bot tom strap portion 42, the upper and lower strap portions 41 and 42 being connected by generally arcuately shaped end or journal portions 43 and 44. In this embodiment it will be noted that the link is initially flat as contrasted to the upwardly bowed surface of link 10 of FIG. 1. It should be understood however that the link of FIGS. 4 and 5 may, if desired, also be formed with an initially upwardly bowed contour; likewise the post type link of FIGS. 1 and 2 may, if desired, be formed with an initially flat contour.

Upper strap portion 41 includes an expanded mid portion 45 which is generally rectangular in outline, as best visualized from FIGS. 5 and 7. Appropriate edges may be chamfered as desired as indicated at 46, for example.

Connecting pins are indicated generally at 17 and 18. Each pin is arranged to connect a leading link, such as link 40, to a trailing link, such as link 49, when it is desired to form a conveyor composed of said links, such as an endless, orbitally movable conveyor belt of the type indicated at in FIG. 8.

A protuberance 52 extends inwardly from the under surface 53 of upper strap portion 41 as best seen in FIGS. 4, 5 and 7. As best seen from FIG. 4, the protuberance terminates a short distance from the inner surface 55 of lower strap portion 42. In a link having a 4 inch pitch, the protuberance 52, like protuberance/22 of FIG. 4, may extend to within about a /4, inch from inner surface 55. As best seenfrom FIGS. 4-6, the protuberance 52 is longitudinally oriented; that is, its major length axis lies in a direction parallel to the direction of movement of the belt link in operation. The protuberance 52 should be of substantial volume and properly located in order to ensure the absence of shrinkage in the upper strap or the protuberance. The volume represented approximately by the configuration shown in the drawing wherein the protuberance is approximately one-third the length of the major axis of the belt link will be satisfactory. In this instance the vertical elevation of the protuberance (as viewed in FIGS. 4 and 6-8) is substantially rectangular in side outline.

As best seen in FIG. 6, the conveyor belt link is most economically manufactured by the shell molding process wherein a single runner and two gates simultaneously feed two castings. The runner is indicated generally at 57 and the gates at 58, 59. After shake out, the runner and gate sections will be separated from the final casting along severance lines 60, 61 respectively. The cross section configuration of the gates 58, 59 may vary from installation to installation. It will be noted that gates 58,59 are located on the exterior surface of upper strap portion 41 substantially opposite the interior protuberances 51, 52 as best seen in FIG. 6.

The shrinkage characteristics of the link are best seen in FIGS. 4 and 7, and FIG. 7 particularly, where the shrinkage associated with the upper strap portion is indicated at 63 in runner 57. Due to the placement of gate 59 substantially directly opposite protuberance 52, the shrinkage will be formed in gate 57 rather than in the protuberance 51 or upper strap portion 41. The shrinkage in lower strap portion 55 will be minor and practically harmless, due to the thinness of the section and, for purposes of illustration, is indicated somewhat diagrammatically by the line 64.

The conveyor with which this embodiment is used consists, in this instance, of a large number of individual belt links 40a similar to belt link 40 which have been secured one to another. by suitable connecting means, such as the pins 17, 18. In FIG. 8 the individual belt links are indicated in the position they will assume after long exposure, such as two years or longer, to the high temperature furnace with which they are used; that is, the lower strap portion 42 will have been deformed or bowed inwardly to substantially the position indicated at 42a in FIG. 4, in which the upper surface 55 of the link contacts the lower surface of protuberance 52. If the conveyor belt link is subjected to considerable stress at high temperatures for prolonged periods, there may be some deformation of the upper strap portion of the link to the position indicated at 41a; In this event there may be a slightly further deformation of the lower strap portion.

One advantage of the illustrated constructions is that the protuberances 22 or 52 strengthen the upper strap 11 or 41 to a marked degree. For example, a prior art link which did not have rib 52 had a sectional modulus of .0123, whereas the same link with rib 52 added had a sectional modulus of .0334, which represents a 143 percent increase in strength of this member.

In the production of the belt link of the invention, a shell mold assembly 68 is formed having a runner 57 feeding two cavities for individual links through gates 58 and 57. Hot metal poured into the mold will produce an interiorly sound casting since the shrinkage will be substantially as shown in FIG. 7 wherein the runner 57 functions as a hot metal storage reservoir feeding into the cast link as solidification proceeds.

In use individual lengths are connected one to another as by connecting pin 17 to form a substantially flat load bearing surface adapted to receive and support loads, such as crankshafts, in a heat treat furnace.

By suitable proportioning of parts, as by making expanded mid portion 45 exactly twice the width of arcuate end portions 43 and 44, a substantially continuous surface area can be provided.

As the conveyor belt moves through the furnace,

I which may, for example, be-in the temperature range of anywhere from about 1650F to 1850F for from about 3 hours to 1% hours, the individual beltlinks will become semi-plastic. If relatively heavy loads are supported there may be a gradual squeezing or bowing of the upper and lower strap portions 11, 41 and 12, 42 as indicated by thedeformed positions 11a, 41a and 12a, 42a of FIGS. 1 and 4, and this condition may be accentuated when the links come into contact with, and pass around, the curved surface of drive drum 27.

necting pins 17 and 18 would be pinched, and opera-- tion thereby hindered, is prevented by protuberances 22 or 52, which serve as an abutment beyond which lower strap portions 12a, 42a cannot deform.,As will be noted from the deformed positions of FIGS. 1 and 4, even in this maximum deformed condition there is still ample clearance for connectingpins '17, 18 whereby malfunction of the conveyor due to pinching of the pins is eliminated.

It will also be noted that thesubstantiallyelongated configuration of protuberances -22 or 52, and their placement in generally coextensive relationship with gate 59 substantially eliminates any shrinkage in upper strap portion 11 or 41. What shrinkage does occur will occur in runner 57 with the result that upper strap portion 11 or 41 will be sound and free of defects. The hairline shrinkage 34 or 64 occurring in lower strap portion 12 or 42 will be of an insufficient nature to hinder performance of the link, as those skilled in the art will appreciate.

FIGS. 9 and 10 have been included for purposes of comparison. In the prior art structure of FIGS. 9 and 10 there is shown a small round post 71, which extends from upper strap 72 to lower strap 73, and is used to prevent closure of the end or journal portions of the link. However, the useful life of the link is considerably shorter than the useful life of the new link of this application due to corrosion failure of the post. Specifically, since this casting can only be fed economically from one side, shrinkage will occur between the post 71 and the strap associated with the non-gated side (here, strap 72), as represented for example by the irregular cavities 76, 78 in top surface 77 and bottom surface 79 respectively, of strap 72. The presence of the shrinkage cavities with the accompanying deleterious features mentioned earlier results in the illustrated corrosion failures. In some instances the presence of the post may do more harm than good since, if a shrinkage hole open to the furnace atmosphere is present when the casting is new, a focal point for rapid corrosion has been provided.

Although a preferred embodiment of the invention has been illustrated and described it will at once be apparent to those skilled in the art that further modifica-' tions may be made within the spirit and scope of the invention. For example although a cylindrical and an elongated, generally rectangular protuberance have been illustrated and described in detail, other shapes, such as triangular, or other dispositions, such as transverse,,may be used. It is essential however that the protuberance, irrespective of its shape and/or location, terminate short of contact with the strap portion opposite the strap portion from which it extends. Accordingly the invention is not to be limited to the exact disclosure shown; rather, the scope of the invention is to be determined from the hereinafter appended claims when interpreted in light of the pertinent prior art.

I claim:

1. A high temperature conveyorbelt link, said belt link including an upper'strap portion, and

a lower strap portion,

said upper and lower strap portions being connected by generally arcuate shaped journal portions to define an open interior, I r

said upper strap portion having an upper surface constructed and arranged to receive and support loads placed thereon,

said belt link being adapted to receive common connecting means, such as a link pin, at its end por tions whereby a plurality of similar belt links can be connected one to the other to form a combined as-- semblage, and

means for preventing deformation of a bottom strap portion with respect to the top strap portion to a degree sufficient to hinder operation of'the connection means,

said deformation preventing means including a protuberance extending into the interior of said belt link from one of said strap'portions,

said protuberance terminating, initially, short of contact with the other strap portion, but extending a distance sufficient to preclude binding of said connecting means when said other strap portion deforms during use to a point at which it contacts 7 said protuberance.

2. The high temperature conveyor belt link of claim 1 further characterized in that said protuberance is substantially circular in cross section. 3. The high temperature conveyor belt link of claim further characterized in that said upper strap portion has an initially upwardly bowed configuration. 4. The high temperature conveyor belt link of claim 1' further characterized in that the protuberance is located substantially mid-way between the sides of the associated strap portion, whereby a substantially centrally located gating area is available on the surface of the strap portion opposite the surface from which the protuberance extends. 5. In a hightemperature conveyor belt, a plurality of conveyor belt links, each of said individual belt links having an upper strap portion and a lower strap portion, said upper and lower strap portions being connected by generally arcuate shaped journal portions to define an open interior, said upper strap portion having an upper surface constructed and arranged to receive and support loads placed thereon, each belt link being adapted to receive common connecting means, such as a link pin, at its end portions whereby a plurality of similar'belt links can be connected one to the other to form a combined assemblage, and 7 means for preventing deformation of a bottom strap portion with respect to the top strap portion to a degree sufficient to preclude interference with operation of the connecting means, said means comprising a protuberance extending into the interior of said belt link from the under surface of one of said strap portions, said protuberance terminating, initially, short of contact with the other strap portion, but extending a distance sufficient to preclude binding ofsaid connecting means when said other strap portion deforms during use to a point at which it contacts said protuberance.

6. The high temperature conveyor belt of claim 5 further characterized in that said protuberance is substantially circular in cross said upper strap portion having an upper surface constructed and arranged to receive and support loads placed thereon,

said belt link being adapted to receive common connecting means, such as a link pin, at its end portions whereby a plurality of similar belt links can be connected one to the other to form a combined assemblage, and I means for preventing deformation of a bottom strap portion with respect to the top strap portion to a degree sufficient to hinder operation of the connecting means,

said deformation preventing means including a protuberance which is elongated in a direction parallel to a line extending between the journal portions of the link integrally formed with and extending from one of said strap portions into the interior of said belt link toward the other of said strap portions,

said protuberance terminating, initially, short of contact with the other strap portion, but extending toward said other strap portion a distance sufficient to preclude binding of said connecting means when said other strap portion deforms during use to a point at which it contacts said protuberance.

8. The high temperature conveyor belt link of claim 7 further characterized in that the length of said protuberance is approximately onethird the length of the major axis of the belt link.

9. The high temperature conveyor belt link of claim 8 further characterized in that said protuberance is substantially rectangular in cross section. 10. The high temperature conveyor belt link of claim 8 further characterized in that said protuberance extends from the inner surface of said upper strap portion towards the inner surface of the bottom strap portion to a point closely spaced from said inner surface of said lower strap portion. 11. The high temperature conveyor belt link of claim 7 further characterized in that the protuberance is located substantially mid-way between the sides of the associated strap portion, whereby a substantially centrally located gating area is available on the surface of the strap portion opposite the surface from which the protuberance extends. 12. In a high temperature conveyor belt, a plurality of conveyor belt links, each of said individual belt links having an upper strap portion, and a lower strap portion, said upper and lower strap portions being connected by generally arcuate shaped journal portions to define an open interior, said upper strap portion having an upper surface constructed and arranged to receive and support loads placed thereon,

each belt link being adapted to receive common connecting means, suchas a link pin, at its end portions whereby a plurality of similar belt links can be connected one to the other to form a combined assemblage,

means for preventing deformation of a bottom strap portion with respect to the top strap portion to a further characterized in that said protuberance is substantially longer in one direction than in a transverse direction in section. 14. The high temperature conveyor belt of claim 13 further characterized in that said protuberance is substantially rectangular in cross section and extends from the inner surface of said upper strap portion towards the inner surface of the bottom strap portion to a point closely spaced from said inner surface of said lower strap portion.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1243537 *Aug 26, 1916Oct 16, 1917John LynnTransmission chain or belt.
US1427008 *Aug 14, 1920Aug 22, 1922Shigeru MatsumotoMetallic link belt
US1631580 *Dec 8, 1923Jun 7, 1927Cavanaugh William MBelting
US1907636 *Jan 20, 1932May 9, 1933Woodman Francis NLink conveyer belt
US2229106 *Dec 13, 1939Jan 21, 1941Lewis LomandoChain
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4618056 *Mar 23, 1984Oct 21, 1986Omega Castings, Inc.Link conveyor belt for heat treating apparatus
US4903824 *Feb 6, 1989Feb 27, 1990Kanto Yakin Kogyo K.K.For use at a high temperature
Classifications
U.S. Classification198/851, 474/247
International ClassificationF16G13/00, F16G3/02, F16G13/08, F16G3/00
Cooperative ClassificationF16G13/08, F16G3/02
European ClassificationF16G3/02, F16G13/08
Legal Events
DateCodeEventDescription
Jan 22, 1981AS02Assignment of assignor's interest
Owner name: FAHRENWALD, FRANCIS M.
Owner name: YORKE, NATHAN, ASSIGNEE FOR THE BENEFIT OF CREDITO
Effective date: 19800619
Jan 22, 1981ASAssignment
Owner name: FAHRENWALD, FRANCIS M.
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:YORKE, NATHAN, ASSIGNEE FOR THE BENEFIT OF CREDITORS OF FAHRALLOY COMPANY;REEL/FRAME:003824/0853
Effective date: 19800619