US3550225A

US3550225A - Concrete pipe molding assembly

Info

Publication number: US3550225A
Application number: US709616A
Authority: US
Inventors: Burton D Smith
Original assignee: BURTON D SMITH
Current assignee: BURTON D SMITH
Priority date: 1968-03-01
Filing date: 1968-03-01
Publication date: 1970-12-29
Anticipated expiration: 1987-12-29

Description

Dec. 29, 1970 a. 0. SMITH CONCRETE PIPE MOLDING ASSEMBLY Filed March 1, 1968 F/GJ INVENTOR BURTON 0. SMITH ATTORNEY United States Patent 3,550,225 CONCRETE PIPE MOLDING ASSEMBLY Burton D. Smith, 1014 Hilton St., Monroe, La. 71201 Filed Mar. 1, 1968, Ser. No. 709,616

Int. Cl. B28b 21/16 US. Cl. 25-30 10 Claims ABSTRACT OF THE DISCLOSURE A concrete pipe molding assembly having vertically disposed, coaxial, outer and inner forms, spaced to provide an annular pipe-forming area there-between. The inner form or core is vertically slidable in the outer form and has associated therewithin a detached, underlying vibrator which, in the operation of the assembly,- is urged into contact with an abutment on the inner form to consolidate the concrete mix fed to the space between the forms. Means are provided for slidably retracting the inner form after the mix has been consolidated to the required extent, and an adjustable stop is adapted to halt the upward movement of the vibrator and limit its contact with the inner form just before the inner form rises outof the bell ring of the outer form. After retraction of the inner form, the outer form is removed, leaving the formed pipe on the curing floor.

OBJECTS For many years, concrete pipe sections, especially those having inside diameters of 6" through 24" and lengths from 4' to 8', have been produced on packer head machines, and while such machines will press the moist concrete tightly against the outside form or mold, the process lacks the facility of encouraging the particles in the mix to seek their most favorable position. Therefore, various methods to accomplish this purpose of particle placement by vibration have been developed.

Most of these vibrating machines are of such a nature as to seriously damage the forms because they are physically connected to one form or the other. Furthermore, they are relatively slow, usually making use of cumbersome means in the application of pressure to the spigot or upper end of the pipe section. This has been necessary in order to make the pipe section conform to the finer detail normally found at that end of the pipe.

The primary object of the present invention is to provide a concrete pipe manufacturing assembly employing a vibrator which avoids damage to the forms and utilizes an inner form or core which is relatively expendible.

Another object of the invention is to provide a pipe forming assembly including a vibrator which, while completely detached from the core, is selectively pressed against it during operation.

Still another object of the invention is to provide means for maintaining abutment of the vibrator and core in such a manner as to avoid rigid connections between the two which would result in tearing of the metal and shorter core life.

A further object of the invention is to provide an assembly such as described, wherein the vibration can be stopped instantly as far as its effect on the moist concrete is concerned. By having the vibrator follow the core as it is withdrawn from the newly formed pipe until it contacts a stop which is placed in optimum position to insure discontinuance of vibration before the core clears the bell-forming ring, damage to the pipe is prevented.

With the above and other objects in view which will appear as the description proceeds, the invention consists in the novel features herein set forth, illustrated in the 3,550,225 Patented Dec. 29, 1970 accompanying drawings, and more particularly pointed out in the appended claims.

THE DRAWINGS Referring to the drawings in which numerals of like character designate similar parts throughout the several views:

FIG. 1 is a more or less diagrammatic view of the as sembly in side elevation;

FIG. 2 is an enlarged, transverse, sectional view taken on line 22 of FIG. 1, illustrating the bottom master pallet; and

FIG. 3 is an enlarged, vertical, sectional view through the outer form and inner core assembly.

In the drawings, 5 generally represents the vertical frame of the machine and preferably extends upwardly from a well 6 in the floor, as is conventional. Cross-bars 7 extend across the frame just below floor level and are spaced to support the bottom master pallet 8 which, as will be seen from FIG. 3, comprises a plate having a central opening 9 and provided on its upper face with a series of lugs 10 for centering the bottom or bell section 11 of the outer form 12. As upper master pallet 13, having a central opening 14, centers the upper end of the outer form 12, and its lower surface is provided with tfiownwardly projecting lugs 15 for centering the outer orm.

It may be noted that the outer form may be of the type made up of two halves with throw latches to fasten the halves together, or it may be of the type designed to strip vertically from the newly made pipe and constructed in one piece. For purposes of understanding this invention, the type of the outer form is immaterial, and therefore it is shown more or less diagrammatically in the drawings.

The inner form or core 16 comprises a cylinder of suitable metal of a diameter sufiiciently less than the outer form 12 to provide an annular space for receiving the concrete mix to be used in forming the pipe. The upper end 17 of the core is conical in shape, protruding through the central opening 14 of the top master pallet 13, where it is connected to a shaft 18 by a rubber coupling 19. The shaft 18 is under the control of and hydraulic ram 20 at the upper end of the frame 5, thus the position of the core 16 within the outer form 12 is controlled by by the shaft 18 and ram 20.

It the form of the invention shown, the bottom of the core 16 is open and provided with an inset vibrator block 21 which, as will later appear, provides an abutment for the vibrator 22, as best seen in FIG. 3.

The details of the vibrator per se are not important to the present invention, as there are a great many different types of commercial vibrators on the market which may be used. Some of these are powered by air and others by electricity, and in either case, most of them produce the vibration by the high speed rotation of an eccentrically loaded shaft.

The vibrator 22 is provided with a downwardly extending shaft 23, the lower end of which projects through openings in two

cross-bars

24 and 25, as seen in FIG. 1. Preferably, the shaft 23 passes through rubber bushings 26 in the

cross-bars

24 and 25 to minimize the transfer of the vibration to the frame, and a coil spring 23a is interposed between the bottom of the vibrator 22 and the upper cross-bar 24. Beneath the cross-bar 25, the shaft 23 is provided with a stop collar 27 which is adjustable on the shaft to control the upward movement of the vibrator and to regulate the point at which the vibrator ceases to contact the vibrator block 21 on the core 16.

The lower end of the outer form 12 is provided with a bell forming ring 28, having a central opening 30 which encircles the lower end of the core 16 and rests upon a support ring 29 on the inner face of the flared end 11 of the outer form. The opening in the bell ring also acts to center the lower end of the core in the outer form.

The purpose of the coil spring 23a is to maintain contact between the upper end of the vibrator 22 and the vibrator block 21 within the limits of the selected placement of stop collar 27 on shaft 23. It is felt that this method of mounting the vibrator would be most satisfactory and would be used except in machines producing pipe sections longer than 4' or larger than 12" in inside diameter. For the larger sizes and longer lengths, it would probably be necessary to use a ram for controlling contact of the vibrator with the core so that the vibrator could be withdrawn below the elevation of the base ring to facilitate the removal of the finished pipe from the machine. Furthermore, larger or longer pipe sections would probably require that the vibrator be positioned higher, i.e. nearer the center of gravity of the pipe section.

Adjacent the upper end of the forms, a hopper 31 is provided for feeding suitable concrete mix to the forms by means of an endless conveyor 32. This is all conventional machinery and need not be described in detail.

In operating this assembly, it is necessary that the top master pallet 13 be raised and lowered to release and engage the top of the outside form. This is accomplished by the use of rams 33, operatively connected by members 34 to the top master pallet 13, as diagrammatically shown in FIG. 1.

In operation, after the outer form and core are assembled as described, the concrete mix, in an earth moist condition, is poured into the space between the upper end of the core and the outer form, the conical shape of the core at this point automatically deflecting the mix into the space between the two forms. The vibrator is then started, and as the concrete is fed into the form, the vibration of the core 16 by the vibrator 22 causes the proper distribution of the mix in forming the pipe. After a suitable interval of vibration, the core form is retracted by the ram 20 and shaft 18, and just before the core form rises out of the bottom pallet and bell ring, the upward travel of the vibrator 22 ceases because of contact of the stop collar 27 and the cross-bar 25, so that its contact with the core 16 is broken. The retraction of the core form continues until its bottom is above the top of the upper master pallet 13. The upper pallet is raised by the rams 33, and the outer form containing the bottom pallet and the newly formed pipe is removed from the machine. The outer form is removed from the newly formed pipe which is left standing on the bottom pallet on the curing floor. It is estimated that this complete cycle takes less than one minute.

Although forming no part of the present invention, a bell ring turning stand may be employed to rotate the bottom pallet as the pipe is being formed so as to produce a smooth inner surface on the female end of the pipe. Also, means may be provided for rotating the core for this same purpose on the pipe inside.

It is to be noted that one of the primary advantages of the present arrangement resides in the fact that the vibration of the core may be stopped without stopping the upward movement of the core. This will greatly facilitate the removal of the core from the newly formed pipe without danger of damaging the pipe. In conventional machines embodying vibrators which are fixed either to the core or the outer form, the vibrators must be shut off, and the core cannot be withdrawn until they run down because the vibration will shake the pipe down. Furthermore, by starting the movement of the core with the vibrators stopped, after the concrete has been properly consolidated by vibration, it would almost certainly result in tearing the finished product.

Another advantage of the invention is that it provides compaction of the mix in the spigot end of the pipe. This is accomplished by the conical upper portion of the core. As the core is withdrawn, its conical upper portion presses the concrete mix against the outer form, the top master pallet and the top forming ring.

From the foregoing, it is believed that the invention may be readily understood by those skilled in the art without further description, it being borne in mind that numerous changes may be made in the details disclosed without departing from the spirit of the invention as set forth in the following claims.

I claim:

1. A concrete pipe molding assembly comprising an open-ended outer form, means supporting said form in vertical position, a coaxial inner core, retractible through the upper open end of said form, means connected to the upper end of said core for supporting and independently retracting the latter through the adjacent open end of said form, said core having a transverse abutment, a vertially moveable vibrator extending through the lower open end of said outer form and underlying said abutment, said vibrator being completely detached from said outer form and core, means normally urgin said vibrator into physical contact with said abutment to vibrate said core when the latter is in its lowermost position with respect to said outer form and for maintaining continued vibrating contact with said abutment for a predetermined time during the retraction of said core from said outer form, and stop means for defining the limit of the upward movement of said vibrator and its contact with said abutment.

2. An assembly as claimed in claim 1, wherein said means for supporting and retracting the core comprise a connecting shaft and an hydraulic ram.

3. An assembly as claimed in claim 2, wherein said shaft is connected to said core by a rubber coupling.

4. An assembly as claimed in claim 1, wherein said means for urging said vibrator into contact with said abutment comprises a coil spring interposed between said vibrator and an underlying fixed cross-bar.

5. An assembly as claimed in claim 4, wherein said vibrator is provided with a depending rod and said stop means comprise a stop collar vertically adjustable on said rod, and fixed means engageable by said collar to limit the upward movement of said rod.

6. An assembly as claimed in claim 5, wherein said depending rod passes through a resilient bushing in said fixed cross-bar.

7. An assembly as claimed in claim 1, including top and bottom master pallets for retaining said outer form in place and centering the same.

8. An assembly as claimed in claim 1, wherein the lower end of said outer form is provided with a bell-forming ring.

9. An assembly as claimed in claim 8, wherein said bellforming ring has a central opening to receive and center said core.

10. An assembly as claimed in claim 1, wherein the upper end of said core is conical in shape to facilitate compaction of the mix at the spigot end of the pipe.

References Cited UNITED STATES PATENTS 2,679,384 5/1954 Livingston 25 41x 3,078,539 2/1963 Duplessis 25-30 3,083,433 4/1963 Tiller 25-39 3,119,165 1/1964 Gourlie 25 30 3,273,216 9/1966 Gourlie 25- 30 J. SPENCER OVERHOLSER, Primary Examiner BEN D. TOBOR, Assistant Examiner US. Cl. X.R. 2541