US2517974A

US2517974A - Centrifugal casting apparatus

Info

Publication number: US2517974A
Application number: US47111A
Authority: US
Inventors: George L Chase
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-08-31
Filing date: 1948-08-31
Publication date: 1950-08-08
Anticipated expiration: 1967-08-08

Description

g- 8, 1950 G. L. CHASE 2,517,974

CENTRIFUGAL CASTING APPARATUS Filed Aug. 31, 1948 I 2 Sheets-Sheet 1 Q i Q INVENTOR. h .GEOEGE CHASE,

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Aug. 8, 1950 G. L. CHASE 2,517,974

- CENTRIFUGAL CASTING APPARATUS Filed Aug. 31, 1948 2 Sheets-Sheet 2 INVENTOR.

GEOEGE L CHASE,

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Patented Aug. 8, 1950 UNITED STATES PATENT OFFI'CE CENTRIFUGAL CASTING APPARATUS George L. Chase, Wharton, N. J. v ApplioationiAugust 31, 1948,'Serial No. 47,111

This invention relates to. centrifugal casting apparatus, and -more particularly to improved apparatus for centrifugally casting concrete pipe' or culvert sections and similar structures.

In centrifugally casting concrete pipe or culvert sections, it is customary to place a cylindrical, tubular frame having end rings therein, over a thin metal casing, secure removable rings, one in each end of the frame, surrounding the corresponding ends of the casing to hold the ends of the casing centered in the frame and extending annularly inward of the casing to provide abutments for a concrete lining cast in the casing, and then place the frame and included casing in horizontal position on a frame-spinning machine and feed plastic concrete into the interior of the casing until a concrete lining of a desired thickness has been provided in the casing.

In order to support the casing intermediate its length, hold the casing centered relative to the frame and provide a firm torsional connection between the casing and the frame, a girth band in the form of a split ring of rectangular cross-section is secured about the casing substantially at its mid-length location, and angularly spacedapart set screws carried by the frame and extending radially inwardly of the wall of the latter are brought into contact with the girth band to center and support the casing in the frame and provide a driving connection between the frame and the casing,

This practice involves numerous objections and defects which it is among the objects of the present invention to'overcome. For one thing,- the casings are not of identical circumferential size, so that in some cases the girth band will fit loosely, permitting both rotational and radial movement of the casing in the frame'and causing or permitting vibration of the assembly, and'in other cases, will fit so tightly as to draw in the casing at'the location of the band, distorting and frequently cracking the casing and setting up stresses which cause cracks in the concrete lining.

The use of the girth bands is also time consuming, requires a large amount of manual labor and results in an excessively high percentage of imperfect castings. 1

The present invention contemplates the elimination of the girth bands and the use of pneu matic means instead, and has among 'itsobjects the provision of improved means for centering and supporting the casings in the framesi'and for firmly supporting the casings over substantially'their entirelellgth. Without distorting 91c- 6 Claims. (01. zs-co) damaging the casings to any extent, which supporting means provides a positive torsional connection between a frame and an included casing, which is quickly-and easily operated to look a casing in a frame and release it therefrom, which is resistant to wear, and efi'ectiveto provide a long period of substantially trouble-free service, which will greatly reduce the percentage of imperfect castings produced, andwhich may beinstalled in a conventional tubular-frame without material modification of the frame.

Other objects and advantages will become apparent from a consideration of the following description and the appended claims in conjunction'with the accompanying drawings, wherein:

Figurel is a longitudinal elevation of a centrifugalncasting tubular frame, a portion being broken away and shown in longitudinal, medial cross-section to illustrate the disposition therein of a tubular casing and concrete lining and pneumatic holding means. operatively interposed between thefra'me and the casing;

Figure 2 is a somewhat diagrammatic end elevation of a loaded casting frame operatively mounted on a frame-spinning machine to produce a centrifugal casting; a

Figure 3 is a transverse cross-section taken su'bstantiallyxon the line 3-3 of Figure 1;

Figure 4 is 'a longitudinal cross-section on an enlarged scaleof a fragmentary end portion of the frame-and-casing assembly illustrated in Figure 1, showing the spigot end of the assembly; Figure 5 is a longitudinal cross-section on an enlarged scale of a fragmentary end portion of the assembly illustrated in Figure 1, showing the bell end of the assembly;

- Figure 6 is an end elevation of the spigot end of the frame-and-casing assembly; and

Figure 7 is an end elevation of the bell end of the assembly.

- With continued reference to the drawings, the assembly illustrated in Figure l-comprises, in general, a frame H], a tube casing H received in and supported by the frame, and a pneumatic holding means l2 operatively interposed between the frame and the casing.

The frame l0 comprises a tubular, cylindrical member [3 of thin-walled construction formed of a hard, rigid and durable material, such as steel, and preferably of seamless construction. A runner rin 14 is permanently secured on one end of the tube I3 by means of an annular flange l5 exteriorly overlying the corresponding end of the tube and secured thereto by suitable fasten--- ,ers, such as rivets or bolts. The ring 14 has an outwardly-extending annular flange or bead l6 and extends inwardly of the tube l3. to provide an annular shoulder I! at its inner side within the tube, a cylindrical inner-surface 18 of smaller diameter than the internal diameter of the tube It, and a beveled annular edge l9 connecting the cylindrical surface ill with the inner edge of the shoulder H.

A spigot ring 29 of angle or L -shape d crosssection is mounted in the runner ring I4 in position such that its inwardly-projecting outer flange 2| receives the corresponding end of the tubular casing H and its radial flange projects inwardly of the tubular casing to provide an inwardly-extendin annular shoulder 22 within the corresponding end of the tubular casing.

The spigot ring 29 is releasably secured'in the runner ring [4 by angularly-spaced buttons 23 secured to the runner ring by respective bolts or cap screws 24 and receives the spigot through which concrete is introduced into the mold :or frame H].

A runner ring 25, particularly illustrated in Figure 5, is permanently secured to the bell end of the frame tube 3 by anwann-ular flange or ring 2% which receives the corresponding end 'of the tube 13 and is secured thereto by suitable fastening elements. This ring has an outwardly-projecting annular bead or flange '21 corresponding to the bead it of the ring 14, and has a cylindrical portion 28 projecting outwardly from the corresponding end of the tube l3 which cylindrical portion '28 has a cylindrical, internal surface substantially flush with the internal surface of the tubel3. A bell ring 29 of L or angle-shaped cross-section has a cylindrical, peripheral surface of a diameter to closely fit into the cylindrical inner-surfaceof the portion28 of the ring and an inwardly-projectin'g, annular flange 35 of a thickness to provide a lining-retaining shoulder 3! within the corresponding endof "the casing H. This end of the casing is voutwardly flared, as indicated at 32 to provide a bell end, and the other annular surface of the flange of bell ring 29 is tapered to closely fit the outwardly-flared end of the casing.

The bell ring '29 is secured in the runner ring 25 and in the corresponding end of the casing l I by suitable buttons each of which has 'a shank 3 extending through a bore provided in the ring 25 longitudinally thereof, an portion 35 at the outer end of the shank overlying and operatively engaging the outer surface of the bell ring adjacent the edge thereof, and a handle '35 projecting substantially at "right angles to the shank at the inner end thereof and in -a direction opposite that from which the corresponding :angular portion 35 projects.- Adjacent the handle the shank 34 is externally screw threaded and a nut 37 is threaded onto the shank to rig-idly lock the buttons in operative position, holding the bell ring 29 in the runner ring '2 5.

The above-described construction is already in use and its operation is substantially as follows:

The spigot ring 2!) and the bell ring '29 are both secured in operative position on the casing, one at each end thereof, and the girth band is secured about the middle of the casing; The spigot ring Zll is secured in centered position on the casing by suitable means, such :as wedges .38 forced between the annular flange Zel of the spigot ring and the outer surface of the casing. The buttons 33 are turned outwardly relative to the center of the runner :ring 28', and the casing with the attached rings is then up-en'ded with the spigot ring at the top. The frame It is elevated above theground in a substantially vertical position above the casing and is then lowered over the easing and spigot ring until the spigot ring contacts the buttons 33. The buttons 33 are then turned inwardly to engage the outer surface of the bell ring near the outer circumference thereof, and the nuts 3'! are tightened to hold the bell ring in firm engagement with the casing. This entire assembly is then placed on the spinning machine with the flanges it and 2? of the runner rings at the inner side of respective pairs of framesupporting wheels 39 of the spinning machine, with the cylindrical portions of the runner rings at the outer sides of the flanges running on the peripheral surfaces of the wheels.

The wheels 39 are journaled on a frame at and driven by a suitable power source, so that the frame--and-casing assembly is rapidly rotated about a substantially horizontal axis. An elongated'tubular nozzle, from 22, cement gun supplying cement or concrete under pressure, is then inserted into the casing through the spigot ring 26 and concrete is placed in the casing between the shoulders 21 and SI to the radial depth of these shoulders, providing within the casing vl I alconcrete lining "l l. The spinning of the framea-nd-casing assembly causes this concrete lining to level out and take a cylindrical shape of substantially-uniform thickness within the casing H.

After the concrete lining has set, the spinning is stopped and the lined pipe or culvert section is removed from the frame by up-ending the assembly with the bell ring 29 at the bottom, loosening the nuts 3? and turning the buttons 33 out of the way of the bell ring, and then raising the frame away from the lined casing ll.

As explained the introduction, it is customary, at the present time, to apply a .girth band to the casing substantially at its mid-length location before the frame is lowered'over the empty casing, and to then secure this girth band in centered position in the frame to support the intermediate part of 'thevcasing 'bythr'eading set screws inwardly through the wall of the frame.

The present invention contemplates the elimination of the girth band .and set-screw mechanism, and the use-of pneumaticmeans-within the frame to resiliently support the casing in the frame substantially from "one end :to'the other of the casing. This pneumatic means comprises a double-walled, tubular structure, generally indicated-at l2, extending from-onezend to the-other of the frame tube 13. The walls of this structure 12 are thin and are formed of a flexible, airimpervious material, such as rubber or a rubberand-fabric composition. Preferably the outer wall 43 and the inner wall 4- 3 are united at their ends, as indicated at 45, to provide between the intermediate portions of the outer and inner walls, an air-tight chamber 46. The inner wall 44 is somewhat longer. than the outer wall d3 and is resiliently stretchible so that it will extend across the annular space between the frame tube IS and the casing I to contact the outer surface of the casing while the outer wall contacts the inner surface of the frame tube, as is clearly illustrated in Figures 1, 4 and 5.

The united end portions of the tubular structure l 2 are firmly secured to the frame by means of flat rings 41 of elongated, rectangular, crosssection fitted one within each end portion of the flexible tubular structure, and secured to the frame by the rivets 43 which extend through the rings 45, the united end portions of the tubular.

structure l2, the frameftube la andtlfie frametube-receiving flanges "a'nd26-"of the 'runner outer wall 43 of the fdouble-walled, pneu ati'c' structure, for the admission of fcompressed' 'air into the chamber 46 betweenthewalls 43 and of the pneumatic device, and" an air-outlet valve 5|, which may also be of conventional construe-r tion, extends through the wall of the frametube l3 and the outer 'wall 43 of-the pneumatic struc ture to the chamber 46 between the walls 43'and 44, and is provided with a' manuallyope'rated handle 52 for quickly releasing compressed air from the chamber 46 withinthe pneumatic istructure I2.

With the tubular, pneumatic-structure]! operatively installed in the frame I0," as de bed above, when the frame is; lowered over?

inner walls

43 and 44 respectively of thepneu matic structure 12, forcing the inner wall '44, of

this structure into firm contact with the outer surface of the pipe casing l l'. Bec'ausef'o'f the equal pressures surrounding the. casingand exerted between the casing'and the frame tube, the casing will be centered in the frame and will be firmly supported over substantially its entire area from one end to theother, and the pneumatic structure Willprovide an effective torsional driving connection between the frame and the casing for spinning of the assembly while the concrete is being applied to the interior: of the casing.

An air compressor of suitable capacity, prefer ably having a storage tank-associated therewith, will be provided, so that the chamber 4,5 within the pneumatic structure can be quickly filled with compressed air, thereby saving large amounts of time at present utilized in installing the girth band on the casing and threading the set screws into proper contact with the periphery of the girth band. As the compressed air is applied by mechanical means, this arrangement also saves an important amount of manual labor. When it is desired to remove the finished pipe or culvert section from the frame, it is only necessary to remove the bell ring 29, release the air from the chamber 46 through the air-release valve 5i, and then lift the frame away from the finished pipe section. Here again, there is an important saving in the time and manual labor. Because of the firm and uniform support of the casing substantially throughout its entire length with resilient compensation for variations in casing size and other factors, no stresses are set up in the casing which would result in imperfect pipe sections, because of the accurate centering of the casing there is little or no vibration of the casing-and-frame assembly on the spinning machine, and because of the firm, uniform support of the casing and lack of vibration, the present hazardous condition of the frames breaking or p pe? casing H and after thebell ring ze hasbeen brought to operative position, valve '51 is'closed stantially eliminated. I

The walls of the pneumatic structure 12 may exploding-while on the spinning machine; issubgbe formed of either pure rubberor of a rubberand-fabric or other composition, as may be'found' convenient or desirable, and, if the frame tube I3 is found to be of sufiiciently air-tight construction the outer wall 43 of the pneumaticstructu're may be eliminated, the air char'nbe'r 46 thenbeing' formed between the flexible inner'wall 44 and the inner surface of the frame tube.

While the invention has'been particularly illustrated and described for use in the spinning i of.

concrete pipe or culvert sections, it may obviously the'scope of the invention.

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 theinvention 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 is! i n 1. An apparatus for centrifugally casting concrete pipeor culvert sections including a cylindrical, tubular frame for concentrically receiving tubular pipe casings, annular runner ring secured to said tubular frame at respectively opposite ends thereof, an inner ring releasably secured one in'each runner ring for holding the ends of a casing in centered position in the frame,- and pneumatic means in said frame between said runner rings for firmly supporting the interme diate portion of a pipe casing in centered position in-saidframe. h Y

2. An apparatus for centrifugally casting, concrete pipe for culvert sections including a cylindrical, tubular frame for concentricallyreceiving vtubular pipe casings, annular runner ring secured to said tubular frame at respectively opposite ends thereof, an inner ring releasably secured in each runner ring for holding the ends of a casing in centered position in the frame, and pneumatic means in said frame between said runner rings for firmly supporting the intermediate portion of a pipe casing in centered position in said frame, said pneumatic means comprising a tubular, thin-walled structure of flexible material disposed in said frame, means firmly connecting the ends of said tubular structure to said frame interiorly of the latter, and an air valve secured in the wall of said frame and communicating with the space between said frame and said tubular structure for the admission of compressed air into said space.

3. An apparatus for centrifugally casting concrete pipe or culvert sections including a cylindrical, tubular frame for concentrically receiving tubular pipe casings, annular runner ring secured to said tubular frame at respectively opposite ends thereof, an inner ring releasably secured in each runner ring for holding the ends of a casing in centered position in the frame, and pneumatic means in said frame between said runner rings for firmly supporting the intermediate portion of a pipe casing in centered position in said frame, said pneumatic means comprising a double-walled, tubular body of flexible material disposed. in said frame between said runner rings-means firmly securing the ends pf said tubular structure to said :frarne interiorly of the-latter ,-and an air valve extending throughrthe wall ofsaid frame and the :outer wall of said tubular structure for the admission of compressed air into the space between the two'walls of. said 'dou ble-walled, tubular structure.

- :4. :An apparatus :for centriiugally-casting concrete pipe or culvert sections including "a cylindrical, tubular frame for concentrically receiving tubular pipe casings, annular runner ring secured to said tubular "frame at respectively pposi-te'ends thereof, an inner ring releasably secured in each runner ring for holding the ends of acasing in centered position in the frame, and pneumatic means in said frame between said runner rings for firmly supporting the intermediate portion of a pipe casing in centered position in said irame, said pneumatic means comprising a double-walled, tubular body of flexible material (disposed in said :frame bet-ween said runner rings, means firmly securing the ends of said tubular structure to said frame interiorly of thelatter, a-n air-inlet valve extending through the wall of said frameand the outer wall of said tubular structure for the admission of compressed air into the space between the two walls of said double-walled, tubular structure, and a manually-operated, air-release valve mounted in thewal-l of said casing and communicating with the "space between the two walls of said doublewalled, tubular structure.

5. An apparatus for centrifugally casting *concrete pipe or culvert sections and including a cylindrical, tubular frame for concentrically receiving tubular'pipe casings and having annular rings secured one to each end thereof, and inner rings reIea-sably secured one in each of said runner rings for holding the ends of the pipe casing in centered position in the frame, pneumatic means in said frame between said runnerrings for .firmlysupporting a casing in centered position said irame, and means firmly securing the ends of said pneumatic means to said tubular frame, said pneumatic means comprising a tubular, thin-Walled structure of flexible material in said frame, and said means connecting said pneumaticrneans at its ends to said frame comprising alpair of rings of elongated, rectangular cross-section disposed one in each end of said frame adjacent the corresponding runner rings and overlying the corresponding ends-of said tubular pneumatic structure, and fastening elements extending through said rings, the end portions of said tubular pneumatic structure and the wall of said frameto firmly secure said tubular structure to said frame at the ends of the former and interiorly of the latter.

6. An apparatus for centrifugally casting concrete pipe -or culvertsections including a cylindrical, tubular frame for concentrically receiving tubular pipe casings, annular run-ner ring secured to said tubular frame at respectively opposite ends thereof, an inner ring releasably secured .in each runner ring for holding the ends of a casing in centered position in the frame, and pneumatic means in said frame between said runner rings for firmly supporting the intermediate portion of a pipe casing in centered position in said frame, said pneumatic means comprising a tubular structure having an inner and an outer wall of thin, flexible, air-impervious material, such two walls being united at their ends to provide between them an air chamber, said pneumatic means being disposed in said'frame between said runner rings, means firmly securing the ends of said tubular structure to said frame interiorly. of the latter, an air valve extending through the wall of said frame and the outerwall of said tubular structure for the admission of compressed air-into the space between the two walls oftsa'id double-walled tubular structure, and a manually-operated air-release valve mounted in the wall of said casing and communicating with'the space between the two walls of said double-walled tubular structure, to release compressed air "from the space between the inner and outer'walls of said structure.

. GEORGE L. CHASE.

REFERENGES CIT-ED The fol-lowing references are of record in the file of this patent:

UNITED STATES IPA'IENTS Number Name Date 1,961,260 Ukropina' June 5, 1934 2,189,071 Kopp Feb. 5, 1940 2,261,815 :Bush Dec. 30, .1941