US 2426998 A
Description (OCR text may contain errors)
Sept. 9, 1947.- c. H. HALL 0mm couvmqog I Filed Sept. 6, 1944 com-m5 A. 66411,
:M/ ATTOR/VFU a Patented Sept. 9, 1 947 CHAIN CONVEYOR Cortice H. Hall, Birmingham, Micli., assignor to The 'limken-Detroit Axle Company, Detroit, Mich., a corporation of Ohio Application September 6, 1944, Serial No. 552,920
6 Claims. 1 This invention relates toimprovements in conveyor devices and has particular reference to an improved conveyor construction for use, for
example, in conveying coal to an automatic mechanical stoker and removing ashes therefrom. The improved conveyor may, however, be used for any purpose for which it is adapted as for moving sand or gravel, grain, sawdust or other granular or small lump or bulk material. type of conveyor contemplated a chain operates through suitable tubes and over sprockets and is provided with flight elements which convey the material being moved along the tubes. The chain is of an endless, link construction and at the ends of the tubes it passes over pulleys or sprockets, at least one of which is power driven to operate the conveyor.
' titles of fine coal or coal dust. This feature of the improved conveyor is of particular importance in stoker operation since, in order to maintain an even fire and avoid fiy ash and soot, and to avoid the formation of large clinkers and coke trees, most of the coal fed to the stoker retort should be of a uniform specified size and relatively free of dust and coal of small grain size.
In conventional screw and ram feed devices, such as are in substantially universal use at present, this crushing or degradation of the coal pre- 'sents a serious problem which is among the objects of the present invention to overcome. For example, a typical comparative test on two sample lots of 100 pounds of bituminous coal of x 1 inch lump size, one lot passed through a chain feed constructed according to the present invention and the other passed through a conventional screw feed mechanism, gave the following resultsf In the 1 Size reduction to the last two sizes was for the screw feed as compared with only 5% for the chain feed. I
It has also been found that, at least partly because of its positive action on the coal, the improved chain feed mechanism functions to deliver a substantially definite quantity of coal per equal time interval when operated at substantially constant speed. Thus, by properly selecting the conveyor size and the operating speed the conveyor may be used to accurately meter the coal fed to the stoker to establish 'a definite rate based on the combustion capacity of the stoker retort.
In addition to its ability to feed the coal substantially at a predetermined rate without material degradation or dimunition in size of the coal lumps, it has also been found that the improved conveyor is substantially trouble free in operation and is economical to manufacture and easy to assemble and install. A feature of particular importance in this respect is that the chain links are so constructed that they may be coupled together or uncoupled only when in a predetermined position relative to each other which position is such that there is no danger of the chain becoming accidentally uncoupled in use. The improved chain is also constructed in a manner such that regular lubrication is not required and, at the same time, the chain operates for long intervals without material wear.
The improved chain type stoker feed has also been found to be entirely free of jamming and stoppages which occur so frequently in screw type feeds that it has been found necessary to provide shear pins or other automatic release means between the screw and drive components of such previous stoker feeds.
With these and other considerations in view it is a major object of the invention to provide an improved mechanical stoker feed that will move even bituminous coal emciently and silently and without reducing the lump size or pulverizing the coal to any objectionable extent.
A further object resides in the provision of a conveyor that is effective to maintain a substantially definite predetermined rate of fuel feed tem in which the chain links may be readily assembled and disassembled but will not; become accidentally uncoupled in service.
A further object resides in the provision of a conveyor chain of the character indicated in which the links are provided with flight portions which are positively held in planes perpendicular to the path of travel of the chain in the tubes or to become uncoupled in the absence of special provision such 'as the spring tensioning device 20 and the special chain construction, to be later described, to overcomethis tendency.
Sprocket I6 is journalled in casing 22 which receives the corresponding ends of the two tubes l8 and I2 and is provided with a base portion 24 which supports the casing and houses a suitable reduction gear train, not illustrated, through which power is transmitted from drive shaft 28 to sprocket I B.
Sprocket 18, at the opposite end of the chain conveyor I4, is journalled in casing 32, which receives the corresponding ends of tubes l and I2.
The adjustable chain tensioning device 20 may be secured to the casing 32 and operatively connected with the slidabl supported axle 34 of sprocket I8.
Other objects and advantages will become apparent from the following'description in connection with the accompanying drawing and from the appended claims.
In the accompanying drawing, in which like reference numerals are used to distinguish similar parts throughout, there is illustrated a suitable embodiment for the purpose of disclosing the invention. The drawing, however, is for the purpose of illustration only and is not to be taken in a limiting or restrictive sense, since it will be apparent to those skilled in the art that various changes in the illustrated arrangement may be resorted to without in any way exceeding the scope of the invention.
In the drawing:
Figure 1 is an elevational view of a conveyor constructed according to the invention as adapted for use with the automatic stoker of a domestic heating plant;
Figure 2 is a plan view of the conveyor shown in Figure 1, a portion being broken away to better illustrate the construction thereof:
Figure 3 is a perspective view of one link of the conveyor chain;
Figure 4 is a sectional view or the socket end of a conveyor link chain taken on lined-4 of Figure '7 and showing the reception therein of the associated end of an adjacent link;
Figure 5 is a fragmentary plan view of one of the sprockets and a part of the conveyor chain;
Figure 6 is a sectional view on the line 5-6 of Figure 5; and V Figure 7 is a detail view of the coupling means of adjacent chain links with the links disposed in the proper relative angular positions to be coupled or uncoupled.
With continued reference to the drawing and particularly to Figures 1 and 2, the illustrative conveyor mechanism is shown as comprising a pair of tubes, l0 and I 2, a chain, generally indicated at M, passing through the tubes and trained around a drivin sprocket l6 located in spaced relationship to the tubes at one end thereof. The chain also passes around a similar sprocket at the opposite ends of the tubes, as indicated at 18 in Figure 5, and moves through one of the tubes in one direction and through the other tube in the opposite direction.
With power applied to only one of the sprockets, the portion of the chain extending through one of the tubes will be under tension and will not be in danger of becoming uncoupled. However, a portion of the chain moving through the other tube will be slack and will have a te de y Assuming that chain l4 moves through tube [0, around sprocket it, toward stoker feed screw 28, the tube I0 may be provided with an opening 36 through which fuel is fed to the conveyor from a suitable chute or bin 38. The bin may be secured to the tube by means of bolting flanges 40 and 42 and bolts 44.
If desired, casing 22 may be provided with suitable ash receiving means and tube l2 provided with a discharge opening connected with a suitable storage space, not illustrated.
Casing 32 may be supported by suitable means such as leg 16 and tubes in and I2 may be supported by suitable legs or brackets, not illustrated.
Tubes and 12 may be of. any suitable construction and may, if desired, be formed from one or more pieces of sheet metal.
The chain, as particularly illustrated in Figures 3 to 7, inclusive, is formed of a plurality of similar or identical unitary links, generally indicated at 50, each comprising an integral structure which may be readily forged or cast from suitable metal, such as iron, steel, brass or aluminum, and the links are constructed so that they may be readily coupled together to constitute an endless chain. as indicated at M in Figure 2.
Each chain link comprises a shank 52, which may be of substantially rectangular or oval cross section, having at one end a transversely elongated, semi-cylindrical coupling head 54 and at the opposite end a similarl elongated head receiving socket, generally indicated at 5B.
The head H is symmetrically disposed with respect to the longitudinal center-line 58 of the shank portion 52. Preferably, however, the end surfaces of the head 54 are somewhat rounded to provide a limited universal movement for the head of an adjoining link in the socket portion and fillets are provided between these and surfaces and the side walls of the shank to strengthen the connection between the head and the end of the shank. The side of the head 54 remote from shank 52 is provided, as indicated at 60, with a flat surface inclined at a. predetermined angle a to the center line 58 of the shank. This angle a is approximately eighty degrees, as is clearly apparent from an inspection of Figure I.
The socket portion 56, illustrated in section; in Figures 4 and 7, comprises the spaced end walls 62 and 64, disposed one at each side or the shank portion 52. The end wall 62 is provided with an inwardly extending flange 65 and the wall 64 is provided with a similar flange 68 projecting toward the flange 66, said flanges Providing shoulders or abutments for the cylindrical surface of an associated coupling head 54 on an adjoining link in a manner which'will presently appear.
These flanges at one of their ends merge into the transverse connecting web 70 between the shank 52 and the end walls 52 and M, as is clearly illustrated in Figure 4. The other ends of the flanges i6 and 68 terminate in spaced relation from the juncture of the shank 52 with the web it, as in dicated at E2 in Figures 3 and 7, to provide an opening for the insertion of the coupling head 5d of an adjoining link into the space between the portions 62 and 6&1. The space between the inner opposed edges of the flanges 66 and t8 slightly exceeds the thickness of the shank 52 of an adjoining link, so that the latter may freely move between said flanges in the relative angular movement of the links.
At the opening indicated by it in Figure 3 the shank 52 is provided with an obliquely inclined portion having an outer flat surface "it which merges with the inner face of the web W at one edge thereof and is disposed at an angle b to the center line of the shank, this angle 1) being preferably about. 30 or 40 degrees. The outer'inclined surface it of the shank is tangential to the outer periphery of the web it.
The opening i2 is of an extent such that the coupling head 5d of the adjoining link can be passed inwardly or outwardly therethrough only when the flat surface 80 of said head is in parallel relation to the fiat surface Hi on the shank 52. This requires that the two links being coupled or uncoupled be disposed at an angle 0 to each other during the coupling or uncoupling operation. This angle 0 is carefully predetermined with relation to the operating conditions of the particular conveyor arrangement but is greater than any angle the links would normally occupy relative to each other during operation of the conveyor, the angle 0 for the construction illustrated preferably being about sixty degrees.
Winglike portions 16 and 18 extend outwardly, one from each end of the cylindrical socket portion 56 to provide flight elements. Where the chain is to be used in a round tube these wings are preferably provided with arcuate outer edge portions, as indicated at 80 in Figure 6, although they may be given any desired shape to conform to the cross sectional shape of the tube with which the conveyor chain is used. With this construction the transversely aligned flights provide conveyor elements which center the socket end of the link in the conveyor tube. As centering of the socket will also center the socket. enclosed coupling head of the adjoining link, the shank portions of the links will be supported with their center lines in substantially parallel coinciding relation to the center line of the tube as the links pass through the tube. Therefore, transmission of tensile strain through the shanks 52 to the coupled ends of the chain links serves to maintain the flight portions substantially perpendicular to the center line of the tube to effectively utilize the full carrying capacity of each flight in the travel of the chain. The construction of the link coupling head and socket also positively prevent twisting of one link relative to the other as the links pass through the tubes and over the chain sprockets while the ends of the socket portions provide cylindrical lateral extensions for engagement by the dual-toothed sprockets to be presently described. As the socket ends are widely spaced, the links are held in proper position as they move around the sprockets and there is no tendency for the chain to become fouled on the sprockets or town off the sprockets.
The loose interfitting connection between the connected ends of adjoining links permits a small amount of universal movement between the links without undue wear or concentration of stresses on the interconnecting link portions and thus insures long service life for the conveyor chain without the necessity of frequent overhaul or repair. The open construction of the sockets and the coacting coupling heads also permits abrasive material such as coal dust or ashes to work out of the joints between the chain links without causing undue wear on the interengaglng portions of adjoining links so that no special protection or lubrication of the link joints is necessary.
With this construction, individual links may be coupled together to form a chain by holding the two links being coupled at the angle 0, illustrated in Figure 7, and inserting the coupling head at the end of one link into the socket at the end of the adjoining link and then straightening the two links with their shanks $2 in substantially aligned relation to prevent the links from becoming disassociated.
The sprockets it and it are of the dualetoothed type, the corresponding teeth $32 and M of each sprocket being spaced apart axially of the sprocket a distance exceeding the thickness of the chain link shanks 52. The side edges of each tooth are preferably slightly convex, as indicated at @t, and connected by the concave seating surfaces til for the cylindrical end portions of the link sockets 56. Thus, the leading edges of the sprocket teeth will have tangential rolling contact with the cylindrical surfaces of the link sockets and material entering between the sprocket teeth is readily dislodged, so that eilective substantially noiseless engagement of the sprocket teeth with the spaced link sockets of the chain is assured.
Adjusting means 20 provides for adjustment of the distance between the sprocket axes to tighten or loosen the chain, this variation being suiiicient to permit positioning two of the links at the angle 0, illustrated in Figure 7, when the distance between the sprockets is at the minimum, and to tighten the chain to an extent that the links can not assume this relative position during operation.
From reference to Figures 2 and 5 of the drawing it will be noted that the open sides of the link sockets 5% face in the opposite direction to the direction of travel of the material through the conveyor tube. so that in the travel of the chain through the tube the possibility that such material may become more or less tightly packed within the link sockets will be obviated. It will also be noted, particularly from Figure 2, that the flight portions of the chain links do not bear against the surface of the tube. In operation the chain is found to tend to center itself in the tube and drag the coal along without undue friction or crushing action. The spacing of the flight portions also is arranged to receive the coal in properly regulated quantities to provide a steady flow with a minimum of friction.
The conveyor may operate in only one direction to move bulk material from one place to another or may operate in both directions to move the bulk material through tube it from a storage place to a place where it is processed or consumed and to move a residue from the processing or consumption space through tube It back to a storage or disposal location.
The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
What is claimed and desired to be secured by United States Letters Patent is:
1. In a conveyor chain of the detachably coupled link type, link members each having a rectangular shank provided with an end portion obliquely inclined relative to the shank axis and terminating in an integrally formed, transversely elongated cylindrical socket having an entrance opening opposed to said inclined end of the shank, said shank at its opposite end having a transversely elongated coupling head provided with .a flattened side iace remote from the shank and in a plane disposed in predetermined angular relation to the shank axis, whereby the coupling head of one link member may be removed through the socket opening of an adjoining link member only when said flattened face of the coupling head of said one link member is disposed in substantially parallel relation to the inclined shank portion of the adjoining link member.
2. In a. conveyor chain of the detachably coupled link type. link members each having an elongated rectangular shank terminating at one end in a transversely extending cylindrical coupling head and at the other end in a transversely extending hollow cylindrical socket, the axes of the head, socket, and of said shank lying in a common plane; said shank adjacent said socket having an inclined portion 'at an angle to said common Plane, one wall of said inclined portion being tangent to the outer surface of said socket and-the opposite wall of said inclined portion intersecting the outer surface of said socket substantially at said shank axis; said socket being provided with a slot for the insertion of a coupling head of an adjacent link member, one wall of said slot being co-planar with said opposite wall of. said shank inclined portion and the other wall of said slot being parallel thereto said cylindrical coupling head having a planar surface on the side away from said shank for sliding engagement with a said opposite wall oi an inclined portion of the shank of an adjacent link member during assembly of two link members; said socket also being provided with a second slot intersecting said first mentioned slot at right angles for the passage of a shank.
3. The conveyor chain construction defined in claim 2, wherein conveyor nights are provided on opposite ends of said socket and disposed in a common plane substantially bisecting said socket and perpendicular to said shank axis.
4. In a conveyor chain of the detachable coupled link type, link members each having an elongated shank terminating at one end in a transversely extending cylindrical coupling head and at the other end in a transversely extending hollow cylindrical socket, the axes of the head,
. socket, and of said shank lying in a common r 8 plane; said shank adjacent said socket having an inclined portion at an angle to said common plane, said inclined portion having a flat surface parallel to said socket axis and intersecting the outer surface of said socket substantially at said shank axis; said socket being provided with a slot for the insertion of a co pling head of an adjacent link member, one' wall of said slot being coplanar with said flat surface on said shank inclined portion and the other wall or said slot being parallel thereto; said cylindrical coupling head having a planar surface on the side away from said shank for sliding engagement with a flat surface on the inclined portion of the shank of an adjacent link member during assembly of two link members; said socket also be- 1 8 Provided with a second slot intersecting said first mentioned slot at right angles for the passage of a shank.
5. A detachable conveyor chain link comprising an elongated shank terminating at one end in a transversely extending cylindrical coupling head and at the other end in a transversely extending hollow cyindrical socket, the axes of the head, socket, and of said shank lying in a common plane; said shank adjacent said socket having an inclined portion at an angle to said common plane, said inclined portion having a fiat surface parallel to said socket axis and intersecting the outer surface of said socket substantially at said shank axis; said socket bein provided with a slot for the insertion of a coupling head,
one wall of said slot being coplanar with said flat surface on said shank inclined portion and the other wall of said slot being parallel thereto said cylindrical coupling head having a. planar surface on the side away from said shank for slidin'g engagement with a. flat surface on an inclined portion of the shank of an adjacent link member during assembl of two link members; said socket also being provided with a second slot intersecting said first mentioned slot at right angles for the passage of a shank.
6. The link described in claim 5 wherein conveyor flights are provided on opposite sides of said socket and disposed in a common plane substantially bisecting said socket and perpendicular to said shank axis.
CORTICE H. HALL.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 2,100,924 Sinden Nov. 30, 1937 2,110,204 Davis Mar, 8, 1938 Re. 21,172 White Aug. 8, 1939 2,252,460 Sinden Aug. 12, 1941 2,155,874 Sinden Apr. 25, 1939 2,154,707 Sinden Apr. 18, 1939 1,999,484 Sinden Apr. 30, 1935 2,227,557 Sinden Jan, 7, 1941 2,301,084 Sinden Nov. 3, 1942