US3635131A

US3635131A - Slip form curb and gutter machine

Info

Publication number: US3635131A
Application number: US7709A
Authority: US
Inventors: Richard D Larsen; Harold E Miller
Original assignee: Curbmaster of America Inc
Current assignee: Curbmaster of America Inc
Priority date: 1970-02-02
Filing date: 1970-02-02
Publication date: 1972-01-18
Anticipated expiration: 1989-01-18

Abstract

Self-propelled curb and gutter forming machine mounted on continuous traction tread devices. A curb mold form is suspended from the main frame of the machine and extends between the continuous traction tread devices. The main frame of the machine is suspended from the tread devices on three jacks, two of which are provided on one side of the machine and control the grade and a third of which is provided on the opposite side of the machine and controls the slope of the main frame and curb mold form. The curb mold form is vertically pivoted at its front end to a drawbar at the front of the main frame and is suspended from the main frame at its rear end to move laterally about the axis of the vertical pivot. The continuous traction tread devices are driven by independent hydraulic motors, controlled by a variable flow divider valve either manually operated or automatically operated under the control of a sensor biased into engagement with a line extending along the side of the roadway. The three jacks are in the form of self-locking screw jacks driven by individual hydraulic motors. The two jacks on one side of the machine conform the machine to the grade of the roadway and are controlled by grade sensors. The hydraulic jack on the opposite side of the machine conforms the machine to the slope of the roadway and is controlled by a pendulum control.

Description

[451 ,Ian. 1%, I972 SL111? IFIBEIM C'UEIILI AND G'UTTIEEI MAQIIHNIE [72] Inventors: Richard I). Larsen, Denver, Iowa; Harold E. Miller, Milwaukee, Wis.

Qurbrnaster of America, Inc, Cedar Falls, Iowa [22] Filed: Feb. 2, 19711 [21] Appl. No.: 7,709

[73] Assignee:

[52] US. Cl [5 1 Int. Cl. [5 8 ll ield of Search ....94/4l6, 180/648 ..E1lc 119/30 ..94/46; ISO/6.48

Primary ExaminerJacob L. Nackenoff Attorney-Hill, Sherman, Meroni, Gross & Simpson [5 7] ABSTRACT Self-propelled curb and gutter forming machine mounted on continuous traction tread devices. A curb mold form is suspended from the main frame of the machine and extends between the continuous traction tread devices. The main frame of the machine is suspended from the tread devices on three jacks, two of which are provided on one side of the machine and control the grade and] a third of which is provided on the opposite side of the machine and controls the slope of the main frame and curb mold form. The curb mold form is vertically pivoted at its front end to a drawbar at the front of the main frame and is suspended from the main frame at its rear end to move laterally about the axis of the vertical pivot. The continuous traction tread devices are driven by independent hydraulic motors, controlled by a variable flow divider valve either manually operated or automatically operated under the control of a sensor biased into engagement with a line extending along the side of the roadway. The three jacks are in the form of self-locking screw jacks driven by individual hydraulic motors. The two jacks on one side of the machine conform the machine to the grade of the roadway and are controlled by grade sensors. The hydraulic jack on the opposite side of the machine conforms the machine to the slope of the roadway and is controlled by a pendulum control.

22 Claims, 9 Drawing Figures PATENTEB JAN 1 8 i972 SHEET M BF 7 IN VIZN'I'ORS PATENTED .ms 1 8 m2 SHEET 5 0F 7 SILIIF l 'Oiilth/i Gllll lfrl AND MACHINE SUMMARY AND OBJECTS OF THE INVENTION Endless traction mounted curb and gutter forming apparatus drawing a curb mold form along a roadway and accommodating limited lateral movement of the mold form about its front end, to conform to the line of the roadway, in which endless traction devices suspend the main frame of the apparatus including the mold form by a three-point selflocking suspension, conforming the apparatus to the grade and slope of the roadway under the automatic control of a line extending along the roadway, and in which steering of the apparatus may be manual or automatic under the control of the same line. Y

A principal object of the present invention is to provide an improved form of self-propelled curb and gutter forming apparatus arranged with a view toward minimum manual control of the apparatus.

Another object of the invention is to provide a novel and improved form of unitary self-propelled curb and gutter forming apparatus capable of forming a concrete curb and gutter while travelling along the edge of a roadway, without the necessity of providing the usual rails along which the apparatus has formerly traveled.

Another object of the invention is to improve upon the curb and gutter molding apparatus heretofore in use, by suspending the main frame of the apparatus from laterally spaced continuous traction tread devices, and suspending the mold form from the front of the main frame to extend between the continuous traction devices and move laterally relative thereto to readily conform to the line of the roadway.

Another object of the invention is to provide an improved curb and gutter forming machine having a simplified and improved form of suspension for the main frame of the machine from the continuous traction tread devices supporting and propelling the machine, accommodating the machine to conform to variations in the grade and slope of the roadway and holding the frame in its various selected positions, determined by the slope and grade of the roadway, with no attention from the operator of the machine.

A still further object of the invention is to provide an improved form of support and propelling arrangement for a curb and gutter forming machine, all under the control of a line extending along the edge of the roadway, in which manual control and operation of the apparatus independently of the line may readily be selected.

A still further object of the invention is to provide a simplified and improved self-contained self-propelled machine for forming curbs and gutters in which continuous traction tread devices riding on the subgrade take the place of the usual support rails for the apparatus.

A still further object of the invention is to provide an apparatus for forming concrete curbs and gutters in a continuous operation, arranged with a view toward utmost simplicity in construction and efficiency in operation.

Other objects, features and advantages of the invention will be readily apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure.

DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of a curb and gutter forming apparatus constructed in accordance with the principles of the present invention, looking at the apparatus towards the front and one side thereof.

FIG. 2 is a view in side elevation of the apparatus shown in FIG. ll, looking at the opposite side of the apparatus from that shown in FIG. I with certain parts broken away and certain other parts removed.

FIG. 3 is a front end view of the apparatus with certain parts removed.

FIG. 4 is a general diagrammatic view in side elevation of the apparatus looking at the opposite side of the apparatus from FIG. 3, with certain parts removed in order to more clearly show the sensor arrangement for steering and conforming the apparatus to the grade of the roadway.

FIG. 5 is an exploded view showing; the main frame of the apparatus and certain suspension and control parts therefor.

FIG. 6 is a partial fragmentary exploded view, with parts broken away and certain other parts shown in section, in order to illustrate the structure of the jacks suspending the main frame from the continuous traction tread devices.

FIG. 7 is a generally perspective exploded view of the mold form and hopper with certain parts broken away and certain other parts shown in section.

FIG. d is a fluid pressure diagram illustrating the piping connections to the grade and slope conforming jacks, suspending the main frame from the continuous traction tread devices; and

FIG. 9 is a fluid diagram illustrating the piping connections and controls for operating the fluid pressure operated motors for driving the continuous traction tread devices.

DESCRIPTION OF PREFERRED EMBODIMENT OF INVENTION In FIG. I of the drawings, we have shown a generally diagrammatic perspective view of a curb and gutter forming machine III, for laying a curb and gutter along the side of a roadway and including a main frame llll suspended from laterally spaced continuous traction tread devices 112 on jacks A and B at one side of the machine and a jack C at the op posite side of the machine. Said jacks conform said main frame and a mold form 13 carried by said main frame, between said laterally spaced continuous traction tread devices, to the slope and grade of the roadway, in a manner which will hereinafter more clearly appear as this specification proceeds.

The continuous traction tread devices 112 may be of a conventional form, and are each driven from an individual fluid pressure operated motor 15 having driving connection with the associated tread devices at the front end thereof through a conventional sprocket (not shown) meshing with the tread of the tread devices in a well-known manner. The continuous traction tread devices I2 are trained about tread frames 16 forming mounting means for the motors I5 and having a series of rollers 17 spaced along the lower end portions of said tread frames and engaging the lower runs of the tread devices.

The jacks A, B and C are each of a similar construction and are shown in FIG. 6 as being screwjacks. Each jack is in the form of a vertically extending tube shown as being a hollow vertically extending rectangular post Id telescopic within a rectangular tube or post I9 extending upwardly therefrom and forming a suspension means for the main frame ll. As shown in FIGS. 1 and 5, the post I9 of the jack A is partially recessed in a side frame member 20 of the main frame II, and may be welded or otherwise secured thereto. The post I9 of the jack A extends along the corner of a side frame member 21 spaced outwardly of the side frame member 20 and a cross frame member 22 and may be welded or otherwise secured thereto. The post 19 of the jack C is shown in FIG. 5 as partially recessed within a side frame member 23, complementary to the side frame member 20 and may be welded or otherwise secured thereto.

The jacks A, B and C are hydraulic jacks and are shown in FIG. 6 as being self-locking screw jacks, and are particularly advantageous in use as suspending the main frame ill from the continuous traction tread devices 112 and conforming the main frame to various slopes and grades of the roadway, due to the self-locking features of the jacks which make it unnecessary to provide a means for holding the jacks in means to accommodate for leakage in the fluid pressure system. Each jack generally includes the hydraulic motor 25 mounted on a plate 26 disposed adjacent the top of the post 19 and suitably secured thereto. The hydraulic motor 25 is a reversible motor having a drive shaft 27 coupled with a lead screw 29 through a coupler 30. The lead screw 29 extends downwardly through the plate 26 along a support tube 31 depending therefrom, and forming a support for a thrust bearing 32 forming a thrust bearing for the lower end of the coupler 30. A second thrust bearing 33 is carried in the sleeve 3i in a suitable manner and forms a thrust bearing for the upper end portion of the coupler 30, and cooperates with the thrust bearing 32 to retain the lead screw 29 from vertical movement relative to the post 19. The lower end portion of the lead screw 29 is threaded within a thrust nut 35 secured to a mounting plate 36 suitably mounted in the tube 18, adjacent the upper end thereof. The thrust nut is secured to the mounting plate as by a series of bolts 37, or other securing means. A spring 39 encircles each bolt 37 and is interposed between the underside of the thrust nut and the top of the mounting plate 36 to cushion the thrust nut 35. The threads of the lead screw 29 and thrust nut 35 may be acme self-locking threads, to lock the jack in position when the motor 25 is not in operation. Other types of screws, such as ball types of nuts and screws may also be used. A cap 40 is provided for each post 19 and forms a protective closure for the motor 25.

Each post 18 is mounted on and extends upwardly of a yoke 41 having legs 42 extending downwardly along opposite sides of the continuous traction tread devices 12 and secured to the associated tread frame 16 as by transverse pivot members 43.

A stabilizer 44 is provided on the side of the machine containing the hydraulic jack C, to stabilize this side of the machine. The stabilizer 44 includes a rectangular hollow post 45 secured to the main frame 11. at the corner of a hollow cross frame member 46 and a side frame member 47, spaced outwardly of the side frame member 23, and welded or otherwise secured thereto. The cross frame member 46 is shown as being hollow and as having a hollow bar 48 mounted therein and extending inwardly therefrom within a hollow interior portion of the crossbar 22. The connection between the bar 48 and crossbar 22 accommodates widening of the frame for various widths of gutters or paving on principles similar to those shown and described in the Larsen et al. US. Pat. No. 3,202,068, dated Aug. 24, 1965 assigned to the assignee of the present invention, and no part of the present invention so not herein shown or described further.

The hollow rectangular post 45, as shown in FIG. 2 has a rectangular tube 49 telescopically mounted therein and extending upwardly therealong from a yoke 50 extending along opposite sides of an associated continuous traction tread device 12 and tread frame 16, and transversely pivoted to said tread frame, as by a pivot member 51.

The crossbar 22 of the main frame 11 has a platform 53 suitably hung thereon and secured thereto and forming a support for an internal combustion engine (not shown), a pump 56 driven from said engine, and an auxiliary generator 57, supplying the power to operate vibrators 59 in a hopper 60, for the concrete, and set into operation upon the pouring of concrete in said hopper to maintain a uniform flow of concrete from the hopper 60 into the mold 13. The engine may be a conventional form of internal combustion engine and may also drive an alternator (not shown) for maintaining the batteries of the machine charged The mounting for the platform 53 on the crossbeam 22 also forms a mounting for a downwardly facing generally U-shaped bracket 61 (FIG. 3) forming a mounting for a control box 63 extending rearwardly of said bracket member and for a pendulum control box 64 having a pendulum 65 therein controlling the supply of fluid to the slope control jack C to tilt the main frame 11 and mold T3 to conform to the slope of the pavement. The pendulum control 65 is only diagrammatically shown herein, and may be of any conventional form. Said pendulum control in structure is no part of the present invention except insofar as it forms a control for the supply of fluid under pressure to the jack C, so need not herein be shown or described in detail.

Referring now in particular to FIGS 2, 3, 5 and 7 and the suspension of the mold form or mule 13 from the main frame ll, as well as the construction of said mold form, the mold form 113 is in the general form of an inverted pan generally conforming to the shape of the curb and gutter to be paved. Said mold form extends between the continuous traction tread devices 12 and has the hopper 60 mounted in a bottom opening hopper receptacle 66 at the forward end of said mold form, and opening to the interior of said mold form.

The mold form 13 may be of various forms depending upon the required curb and gutter to be molded, as for example, the form may be so formed as to form the curb only, or to form the curb and gutter or to form the gutter only or to mold traffic medians or to widen the pavement. As shown in FIGS. 3 and 7, the mold form 13 has a vertical front wall 67, having a bottom opening recess 69 therein forming a relief recess, accommodating the concrete to flow therethrough when an excess of concrete may be poured into the mold form. Said recess 69 has retainer plows 70 extending forwardly of opposite sides thereof generally triangular in plan and converging toward apices at their forward ends, to retain excess concrete to the mold form, as the machine advances along the pavement.

The front wall 67 has a cutoff plate 71 pivoted to the inside thereof, beneath the discharge end of the hopper 60, for movement about an axis extending transversely of the machine. The cutoff plate 71 is adjustably moved by an adjustment tube 72 and lead screw 73 to restrict the discharge area of the hopper 60 where required. The lead screw 73 is threaded in a nut 74, at the outer end of the adjustment tube 72 and is also threaded in an acme nut 75 carried in a bracket 76 and forming a hanger for said lead screw. Said lead screw extends through the bracket 76 and has a hand wheel 77 secured to its outer end, for turning said lead screw and effecting adjustment of the cutoff plate or valve 71. The hanger 76 is carried between bracket members 79 extending forwardly of the front wall 67, on a nut and bolt 80 forming a pivotal mounting for said hanger between said bracket members, as shown in the exploded view of FIG. 7.

The hopper 60 has converging

end walls

81, 81 and sidewalls 82, 82 converging towards their lower ends to a rectangular discharge end portion fitting within the receptacle 66, and suitably secured to said receptacle. Said hopper may be removed for cleaning or changing the form and size of the hopper, where required.

The suspension means for the curb mold form 13 from the main frame 11 comprises a drawbar 83, shown in FIG. 7 as being a hollow rectangular section and suspended from the main frame 11 on threaded rods or bolts 85, extending through opposite ends of said draw bar and retained thereto as by lock nuts 86 threaded on said bolts and tightened into engagement with the top and bottom sides of said draw bar. The bolts 85, as shown in FIG. 5 depend from generally T-shaped mounting members 87 mounted on bars 88 extending inwardly of the

side frame members

20 and 23 of the main frame 11 and just rearwardly of a front crossbar 89 of said main frame. The bars 88 are shown as being hollow tubular bars, having cylindrical outer peripheries forming pivotal mountings for the mounting brackets or hangers 87. The mounting bolts extend within the depending stems of the mounting brackets and are secured thereto by pins or screws 90, (FIG. 5). Collars 91 limit lateral movement of the T- shaped mounting brackets along the bars 88.

The drawbar 83 has a threaded rod 93 depending from the center thereof, (FIG. 7) in substantial alignment with the longitudinal center of the machine and having a collar 94 secured to its upper end, abutting the top surface of the drawbar 83. A nut and bolt 95 extends through the collar 94 and threaded rod 93 to suspend the threaded rod 93 from the drawbar 83. The threaded rod 93 may be of a relatively large diameter and forms a pivotal suspension mounting for the forward end portion of the mold form 13, accommodating pivotal movement of said mold form between the continuous traction tread devices l2, 12, to enable the mold form to conform to the line of the roadway.

As shown in ZFTGS. 2 and 7, the threaded rod 93 extends H i may be welded or otherwise secured to the front wall d7. Gusset plates Mill serve to reinforce the vertical and horizontal legs of said angle bracket on opposite sides of the apertured portion 96 thereof. The threaded rod 93 is retained to the leg 9'7 of the angle bracket 9'9, as by nuts ti lil. 'l') threaded on said rod and abutting the top and bottom surfaces of the horizontal leg 97. Any suitable locking means may be provided to lock the nuts llll ll in place.

The rear end portion of the mold form l3 has a hanger wi l extending upwardly of opposite sides thereof including a crossbar lltM- extending across the mold form and suitably gusseted to said hanger. The crossbar has collars lltl fi suitably mounted thereon and extending upwardly therefrom, adjacent opposite ends thereof, and forming mountings for threaded suspension rods lilo, extending within and secured to said collars as by nuts and bolts illl'l'. The suspension rods lltlti extend through the bases of upwardly facing U'shaped yolces li -W and are suitably secured to said yokes as by nuts lltl threaded on said suspension rods and locked thereto in a suitable manner.

Each yolre 1W9 extends along opposite sides of a shaft llllll (HO. 5) and is suspended from said shaft as by a flanged spool or roller M2, running along and supporting the yoke and curb form on the associated shaft ill for a limited lateral movement therealong. A second spool or roller llfil is mounted between the legs of the yoke Th9 to engage the underside of the associated shaft ill. and limit upward movement of the mold form relative to the main frame As shown in FlG. 5, one shaft Jill is mounted on and extends inwardly or" a side frame member l? rearwardly of the stabilizer Aid. A coaxial shaft llll extends inwardly of side frame member 27: rearwardly of the suspension jack 8. Each shaft till has spaced collars 11115 mounted thereon limiting lateral movement of the rollers M2 along said shafts and thus limiting lateral movement of the mold form about the axis of the front threaded shaft 93 depending from the drawbar b3.

As is customary with mold forms, the bulk of the mold form is made from sheet steel metal while a rear finishing extension llllb of the mold form is provided extending rearwardly of the hanger 1103 and conforming to the form of the mold form. The finishing section llllb of the mold form may be made from stainless steel and serves to impart a smooth finish to the curb and gutter as the mold form is drawn therealong. The section lib may be detachably secured to form a rear continuation of the mold form, as by turnbuckles 11117, and connector links lllld, in any suitable manner. if desired, drag rails (not shown) may extend rearwardly of the mold and form continuations of opposite sides thereof and the finishing extension may be either in advance or rearwardly of said drag rails, depending upon the particular surface poured.

in H6. '7 one vibrator 59 is shown as extending into the hopper an to vibrate the concrete as poured into said hopper. Said vibrator or vibrators assures a uniform flow of concrete from said hopper to the advance end of the mold form l3 and takes the place of the angers heretofore used for this purpose. in many cases more than one vibrator is provided, particularly where the hopper is relatively wide. in such cases one vibrator may be positioned adjacent one end of the hopper, while the other vibrator may be positioned adjacent the opposite end of the hopper. The vibrator 59 may be of a conventional form, having a vibrating head in the hopper 6d, vibratorily driven by a vibrator motor llZll through a flexible shaft (not shown) contained within a casing 1232. The vibrator motor is energized by the auxiliary generator 57, driven from the internal combustion engine 55. Since the vibrator is conven tional and is no part of the present invention, a detailed description thereof is not necessary for a clear understanding of the present invention.

Referring now to the control for the grade control jacks A and B and the slope control jack C, as shown in lFlG. 4, grade control sensors R23 and for the respective jacks A and B are mounted at the front and rear of the machine along the outer side thereof relatively to the subgrade or roadway, to effect operation of said jacks and conform the machineto the grade of the roadway. The slope control pendulum 65 is mounted above and in advance of the control box or console as, containing the controls for controlling the several operations of the machine, and disposed in advance of an operators platform lid.

The grade control sensors 1123 and H24 engage under a grade line H27 strung along the subgrade of the pavement, along which the traction tread devices travel, and disposed above said subgrade. The sensor i123 includes a control housing i229 mounted on the lower end of a jack T30 and raised or lowered by said jaclr to set a sensor member ll3l to engage under the line M7. The sensor member ll3ll is mounted on the end of an arm T32 pivoted to the housing 129 on a pivot pin T33. A counterweight extends from the pivot pin 133 in an opposite direction from the arm H32, and serves to bias the sensor member llll into engagement under the grade line 127. The housing 129 may contain the controls controlling energization of the valves for supplying llluid pressure to and releasing fluid pressure from the jack A. The controls may include a conventional potentiometer (not shown) transmitting signals to an electrical control circuit (not shown) and at a zero position when the sensor is at a zero position and the jack A has maintained the machine in alignment with the grade line, and moving to one side or the other of zero, to supply fluid under pressure to the jack A, to elevate or lower the main frame relative to its supporting continuous tread device. The potentiometer and electric controls may be of several conventional forms and form no part ofthe present invention, so need not herein be shown or described further.

The housing T29 is mounted on the lower end of the jack TM. The jack llZlll may be a self-locking type of screw jack, raising and lowering the housing T29 and sensor member 131, upon turning movement of a hand wheel 137.

As diagrammatically shown in FM]. 4, the screwjack 130 is mounted on a bracket member i139 adjustably movable along a horizontal support arm Mb. The bracket member T39 may be adjustably moved along the arm Mill in accordance with the position of the grade line 127 relative to the machine, and held in position as by a thumb screw Mil or any other suitable securing means. The arm Mill in turn is mounted on the upper end of a shaft M2 mounted on a bracket member M3. The bracket member M3 is suitably secured to the outer face of the post l9, and extends outwardly therefrom. A thumb screw lid-4i or other securing means is provided to hold the shaft 142 in a selected position, determined by the position of the grade line i237 relative to the side of the vehicle.

The sensor 112d controlling the supply of fluid under pressure to the hydraulic jack B is like the sensor 123 and includes a sensor member M5 pivoted to a control housing M6 and biased into engagement with a grade line R27 by a counterweight Md. The control housing M6 is carried on the lower end ofa screwjack M9 like the jaclr 13b and is operated by a hand wheel lfit) at the upper end of said jack. THc sensor 124 is positioned closely adjacent the curb mold form 13 at the rear end portion of the smoothing trough or finishing section lid of said mold form. The two sensors H23 and T24 are thus positioned beyond the forward and rear ends of the continuous traction tread devices T2 to more readily anticipate variations in the grade and tendencies of the machine to diverge from the grade line.

The screw jack B49 is mounted on a bracket member llSll adjustably movable along a bracket ann T53 extending from a depending vertical shaft portion 155. The vertical shaft portion T55 of the bracket arm T53 is mounted in a support tube llfid, extending upwardly of the forward end portion of the platform Mb. The arm T53 may be adiustably moved about the axis of the shaft and held in position as by a thumb screw 15%, while the jack M9 may be adjustably moved about its axis and held in a selected position by a thumb screw T59 threaded in the bracket member H511.

The grade and slope control hydraulic circuit has parts common to the hydraulic steering circuit and includes a tank 160 containing a hydraulic fluid, such as oil, commonly used in fluid control systems and having fluid connection with the intake of the pump 56 for supplying fluid thereto. The outlet of said pump has connection witha flow control valve 161, through a fluid pressure line 162.

The flow control valve 161 may be of a conventional form and includes a start and stop lever 163 operable to block the flow of fluid to the system and a relief valve 165 returning fluid to tank when the lever 163 is in a stop position. The flow control valve also includes a knob 166 varying the flow of fluid through the valve to a pressure line 167, supplying fluid under pressure to valve blocks 170, 171 and 172 mounted on a base plate 168.

The flow control valve also includes a knob 169 operating a valve member (not shown) of said flow control valve, which controls the quantity of fluid supplied to the hydraulic motors 15, to vary the traveling speed of the machine. The flow control valve 161 including the valve parts thereof operated by the knobs 166 and 169 may be of any conventional form and are no part of the present invention so need not herein be shown or described further.

The three valve blocks 170, 171 and 172 have solenoid operated valves (not shown) therein controlling the supply of fluid under pressure to the jacks A, B and C, in accordance with the positions of the

respective grade sensors

123 and 124. A steering control valve block 173 is mounted on the base plate 168, beneath the valves 170, 171 and 172.

The control console contains electric circuitry means for energizing solenoids 176 and 177 of the valve in the valve block 170, 178 and 179 for the valve in the valve block 171 and 180 and 181 for the valve in the valve block 172, energized by signals from the

sensors

123 and 124. The solenoids 170 to 181 inclusive may also be energized manually by the selective operation of a series of switches 183 and 184 on the top surface of the control console 63. A third switch 185 is provided in alignment with the switches 183 and 184 on the top of the console and is effective to connect the electric circuitry within the control console for manual operation by operation of the switches 183 and 184 or for automatic operation by operation of the

sensors

123 and 124.

In alignment with the switches 185, 183 and 184 is a fourth switch 186 operable when the switch 185 is in the manual position to energize the solenoids 180 and 181 and control the supply of fluid under pressure to the third jack C, to manually control the slope of the machine. The electric circuitry within the control console may be of any conventional form and is no part of the present invention so need not herein be shown or described further.

The control console also has a series of

switches

187, 188 and 189 thereon spaced beneath the switches 185 and 186 inclusive, to effect the manual control of the

traction motors

15, 15. The switch 188 may set the system for manual or automatic control of the continuous

traction tread devices

12, 12. The switch 187 to the left of the switch 188 may energize solenoids 190, provided to operate the valve in the valve block 173, to supply fluid under pressure to a pressure line 193 connected with a variable flow divider valve 212, supplying fluid under pressure to said valve to effect driving of the

motors

15, 15 in a direction to move the machine forwardly or to move the valve in the valve block 173 to effect reverse travel of the motors 15 and continuous traction tread devices driven thereby, as will hereinafter more clearly appear as this specification proceeds.

It should be understood that the switches 183, and 186 are not manually operated unless the switch 185 is in a manual position, and that the

switches

188 and 189 are not manually operated unless the switch 187 is in a manual position. The console also has a meter 197 thereon having a dial 199 indicating the direction of travel of the vehicle. That is, when the dial is in a zero straight-ahead position the vehicle is traveling in a straight line. When the dial is to the right of zero the vehicle will be traveling toward the right and when to the left the of zero will be traveling toward the left. The usual ammeter is also provided on the console, to the right of the

switches

187, 188 and 189.

The slope control pendulum 65 in the control housing or console 63 is provided to control operation of the fluid pressure operated jack C through the valve in the valve block 172 under the control of solenoids 180 and 181. The pendulum and controls in the housing may be of any well-known'commercial construction commonly used on paver finishers and graders, and are effective when the control knob 185 is in an automatic position to energize either solenoid 180 or 181 to supply fluid under pressure through a pressure line 201 or 202 to rotate the fluid pressure operated motor driving the lead screw 29 of the jack C in one direction or another dependent upon the lateral slope of the roadway, to maintain the paving machine in conformance with said lateral slope. The valve block has a return fluid connection 203 leading therefrom having connection with a return line 204 returning fluid back to tank 160. The valve blocks 171 and 172 may have similar return lines connected with the return line 204.

When the switch 185 is in a manual position, the solenoids or 181 may be selectively energized by turning movement of the switch 186 in one direction or another to tilt the machine to conform to the slope of the roadway.

When the

sensors

123 and 124 have been adjusted to come under and engage the sensor line 127, assuming the line 127 conforms to the grade of the roadway, the switch may be turned to its automatic position. If the main frame 11 and mold form 13 starts to move off grade the sensor 123 may then generate signals to effect energization of the solenoids 176 or 177 to operate the valve in the valve block 171 to supply fluid under pressure through the pressure line 205 or 206 to operate the jack motor 25 to elevate or lower the front jack A. The sensor 124 may also generate signals to energize either of the solenoids 178 or 179 to move the valve in the valve block 171 to supply fluid under pressure to the motor 25 for the rear jack B through pressure lines 207 or 208, to operate said motor to raise or lower the jack in accordance with requirements to conform the main frame and mold form to the grade. The two jacks A and B may be independently or simultaneously operated, in accordance with the requirements necessary to maintain the main frame 11 and mold form 13 on grade.

Referring now to the steering circuit under the control of the

switches

187, 188 and 189 on the top face of the control console, the steering circuit, as has been evident from the foregoing description of the grade and slope control circuit is under the control of the knob 169 adjustable to control the volume of fluid supplied to the valve block 173 through a pressure line 209 leading from flow control valve 161. The pres sure line 209 has a variable relief valve 210 connected therein to relive pressure upon closing of the valve in the valve block 173 or when the motors 15 may stall. The valve block 173 is connected to tank 160 through the return line 204 previously mentioned. A pressure line 211 leads from the valve block 173 to supply fluid under pressure to the variable flow divider valve 212. The variable flow divider valve 212 has fluid pressure connection with the two

motors

15, 15 through a pressure line 213 connected with the left-hand motor and a pressure line 215 connected with the right-hand motor. The flow divider valve 212 divides the volume of oil supplied by the pressure line 211 to the pressure lines 213 and 215 and supplies equal amounts of fluid to each pressure line to effect rotation of the two

motors

15, 15 at the same rates of speed for straight ahead travel of the machine. The flow divider valve 212 is varied to vary the flow fluid to one motor or the other in accordance with the direction it is desired the machine deviate from straight line travel by operation of a motor 216 energized to vary the position of the variable flow divider valve 212 upon the receiving of a signal from a sensor 217 engaging the line 127 on the inside thereof. The motor 216 has suitable reduction gearing contained within its housing and has driving connection with the variable flow divider 212 to vary the division of fluid delivered by said valve, as by a timer belt drive 218.

wa t The sensor 217 includes a sensor member 219 pivotally mounted in the housing 221), which may house a potentiometer or other device to send a signal to the motor 216 to effect steering of the machine in the required direction. The housing 22 is mounted on an arm 221 on the lower end of a screw jack 222, like the screw jacks 1211 and 1419, and mounted on an arm 223 for adjustable movement along said arm in accordance with the distance of the left-hand continuous traction tread device from the line 127. The arm 223 is in turn mounted on the upper end of a shaft 224, adjustable about its axis and held in position by a thumb screw or other securing device 225.

As the machine moves along the line 127, the sensor 217 will send a signal to the motor 216 indicating the tendency of the machine to diverge toward or from the sensor line 127 and how much correction is required by the variable flow divider valve 212 to correct this error or variation from true movement along the line 127. As the motor 216 operates the flow divider valve, the volume of oil supplied of the two motors 15, may be varied to speed up the slow side of the machine and slow down the fast side of the machine.

When the machine is parallel to the line 127 no signal isv required and the control components are balanced for continued travel of the machine in a direction parallel to the lien 127.

The variable flow divider valve 212 thus receives a constant volume of oil, which may be regulated by the speed control knob 169, and divides the oil to flow through the two pressure lines 213 and 215, in accordance with the setting of said flow divider valve, by the actuator or motor 216.

When reverse travel of the machine is required, the manual switch 1811 is moved form an automatic to a manual position. The switch 187 is then moved to a reverse position to effect energization of a solenoid 1911 extending from the valve block 173. This will open the valve in said valve block and supply fluid under pressure to a pressure line 227, having connection with a T" 229 dividing the flow through lines 230 and 231 between the two

motors

15, 15 to effect rotation of said motors in reverse directions. The T" 229 may have a flow divider valve therein, is desired. The speed control knob 169 may be operated to vary the volume of flow through the pres sure lines 230 and 231 and the resultant speed of travel of the two motors in reverse directions. The return to tank 161) is through return or bleed lines 232 and 233.

When the switch is in its automatic position, and it is desired the machine travel in a forward direction, the switch 187 may be turned to a forward position and the switch 189 may be operated to effect manual steering of the machine. Steering may be attained by moving the switch 189 to the left of a neutral position for turning to the left, or to the right of a neutral position for turning to the right. This switch should only be used when the switch 188 is in an automatic position and during steering by this switch, the direction of steering is determined by the meter 197 and needle 1198 of said meter.

When the machine is in operation, the continuous traction tread devices 12, 112 usually travel along the subgrade and the curb and gutter are formed between said tread device. Prior to initiating a curb molding operation, the line 127 is strung along the left-hand side of the machine and spaced outwardly of the jacks A and B, which suspend one side of the machine from the associated continuous traction tread device 12. The machine may first be brought in position parallel to the line 129 by movement of the selector switch 188 to a manual position, and by operation of the forward-reverse switch 187 and the steering switch 139, manually controlling operation of the motors 15 and manual steering of the machine.

The jacks A, B and C may also be adjusted by turning the switch 185 to a manual position and manipulating the switches 183, 181 and 196. When the machine is in the proper position relative to the line 127 the grade sensor members 131 and 115 may be adjusted to come under the line 127 in positions in advance of opposite ends of the main frame of the machine, to increase the response to tendencies of the machine to vary from the grade and slope of the roadway. The sensor 219 may then be adjusted to bear against the line 127 and automatically maintain the machine in parallel relation relative to said line.

The selector switches and 128 may then be moved to their automatic positions with the stop-start valve off and the grade control and travel control knob-s 169 and 199 adjusted to deliver the required volume of fluid to the valve blocks 170, 171 and 172, to the variable flow divider valve 212 and the valve block 173. The start-stop valve 163 may then be turned to an on position to allow fluid to flow.

The motors 15 driving the continuous traction tread devices, being supplied with fluid under pressure through the variable flow control valve 212, will propel the main frame 11 to draw the mold form 13 in parallel relation with respect to the line 127, under the control of the sensor 219. The main frame 11 will also be maintained in conformance with the grade and slope of the subgrade by the

sensors

131 and 145, engaging under the line 127. As the machine is initially started, concrete is continuously poured into the hopper 60 by a ready-mix truck (not shown) or other source of supply of concrete, which may travel with the machine.

The draw bar 83 and pivot 93, drawing the mold form along the subgrade, as concrete is poured thereinto, and suspending the mold form from the main frame 111 to effect compression and molding of the concrete as vibrated in the hopper 60 by vibrators and delivered to the mo1d form, thereby attains a uniform curb and gutter smoothed by the smoothing mold form 116 at the trailing end of the mold form.

The mold form is commonly termed a slip mold form because it forms and slips along the formed concrete. The mold form, however, may be interchanged to conform to local specifications, and the machine and slip mold form may be adjusted to various widths of curbs and gutters and may be used for laying sidewalks, traffic medians, and widening roadways, by the interchange of different shapes and sizes of mold forms.

it should here be understood that the vibrators in the hopper plus the compressive action of the mold form limit the need for augers, zero slump concrete and pea gravel, heretofore used in curb laying machines.

It should further be understood that since the main frame 11 is suspended from the continuous traction tread devices 13 by the jacks A, B and C by a three-point suspension, stabilized by the stabilizer 44 that the continuous traction tread devices in addition to riding on the subgrade may be adjusted by operation of the required jacks so one tread device may ride along the pavement while the other tread device may ride along the subgrade, and with the main frame 11 properly adjusted relative to the grade by the jacks A, B and C, the roadway may be laid with the two jacks at different elevations under the control of the

sensors

123, 124 and 219. The machine further is readily adapted to various operating conditions, and the pivotal connection from the draw bar to the mold form at the front end thereof accommodates the mold form to readily conform to the line of the pavement particulaly where the line may be in the form of a long radius curve.

We claim as our invention:

1. In a curb and gutter forming apparatus, the combination comprising,

a main frame,

a pair of laterally spaced continuous traction tread devices,

a mold form,

a suspension draft connection between said main frame and said mold form, accommodating said mold form to conform to the line of the roadway upon movement of the apparatus from straight line movement,

comprising a drawbar at the front of said main frame, and

a vertical pivotal connection suspending the front end of said mold frame from said drawbar,

grade and slope conforming connections between said continuous traction tread devices and said main frame supporting said main frame on said traction tread devices and conforming said main frame and mold form to various grades and lateral sloping conditions of the roadway.

2. The curb and gutter forming apparatus of claim 1,

wherein a laterally slidable suspending connection is provided between said main frame and the rear end portion of said mold form accommodating limited lateral movement of the rear end portion of said mold form relative to the said main frame about said vertical pivotal connectron.

3. The curb and gear forming apparatus of claim 2,

wherein the suspension connection between the rear end of said main frame and said mold form adjacent the rear end thereof, a transverse bar forming a support for said rollers and accommodating said rollers to move therealong, and means limiting movement of said rollers along said bar.

4. The curb and gutter forming apparatus of claim 2,

wherein a hopper extends upwardly of said mold form at the front end thereof and opens to the top of said main frame to supply concrete to said mold form, and

wherein means are provided for varying the discharge of concrete from said hopper to said mold form.

5. The curb an gutter forming apparatus of claim 4,

wherein said mold form has a front wall having an open portion at the bottom thereof, accommodating excess concrete to flow through said open portion, to be formed by said mold form upon advance of said main frame, and

wherein means extend in advance of said front wall forwardly along opposite sides of said open portion, to confine excess concrete to said open portion upon advance of said mold form.

6. The curb ad gutter forming apparatus of claim 1,

wherein a three-point suspension is provided between said main frame and said continuous traction tread devices, to conform to said main frame, continuous traction tread devices and mold form, to varying slopes and grades of the roadway.

7. The curb and gutter forming apparatus of claim 6,

wherein the three-point suspension includes two fluid pressure operated jacks on one side of said main frame, and suspending a first continuous traction tread device from one side of said main frame, and a single fluid pressure operated jack on the opposite side of said main frame suspending the other continuous traction tread device from the other side of said main frame, and

wherein means are provided to control the supply of fluid under pressure to said jacks in accordance with the slope and grade of the roadway.

8. The curb and gutter forming apparatus of claim 7,

wherein said fluid pressure operated jacks each include a hydraulic motor, and a self-locking screw and nut operated thereby.

9. The curb and gutter forming apparatus of claim 7,

wherein thetwo jacks on one side of said main frame are grade controlling jacks and each include a self-locking screw and nut,

wherein an individual fluid pressure operated motor is provided for operating each of said jacks in accordance with the grade of the roadway,

wherein the single jack on the opposite side of said main frame includes a self-locking screw and nut,

wherein an independent fluid pressure operated motor is provided for operating said screw and nut, and

wherein a vertical stabilizer guide is provided on the side of the main frame in association with said one jack, and is pivotally connected to the associated traction tread device and rigidly secured to said main frame to guide the associated traction tread device and accommodate the single jack to tilt said main frame laterally to conform to the transverse slope of the roadway.

10. The curb and gutter apparatus of claim 9 wherein a grade sensor is provided for each grade control jack to individually control operation of said grade controlling jacks,

wherein said grade sensors are located adjacent the front and rear ends of said main frame, and

wherein fluid pressure control means operated by signals generated by sad grade sensors are provided to independently supply fluid under pressure to said grade control jacks in accordance with the grade sensed by said grade sensors.

11. The curb and gutter forming apparatus of claim 9 wherein control means sensing tilting of said main frame about an axis extending longitudinally of said main frame, are provided to control the supply of fluid under pressure to said third jack in accordance with the slope of the roadway.

12. The curb and gutter forming apparatus of claim 10 wherein individual electrically energizable valve means are provided for each of said grade sensor jacks, and

wherein an electrical energizing connection is provided between each of said grade sensors and an associated electrically energizable valve means, to effect the supply of fluid under pressure to said fluid pressure operated motors in accordance with the grade sensed, to rotate said motors in one direction or another or to hold said motors from rotation. 7

13. The curb and gutter forming apparatus of claim 12,

wherein individual electrically energiz'able valve means are provided to control the supply of fluid under pressure to said third fluid pressure operated motor, and

wherein a slope sensing control, sensing tilting of the apparatus about an axis extending longitudinally of said main frame is provided to control energization of said valve means, and the supply of fluid under pressure to said third fluid pressure operated motor, to effect rotation of said third fluid pressure operated motor in one direction or another, or to hold said motor from rotation in accordance with the slope of the roadway.

14. The curb and gutter forming apparatus of claim 1,

wherein individual fluid pressure operated motors are provided to drive said traction tread devices, and

wherein a variable flow divider vale is provided to supply fluid under pressure to said motors to effect steering by supplying a greater volume of fluid to one motor than to the other, and to supply an equal volume of fluid to each of said motors.

15. The curb and gutter forming apparatus of claim 14,

wherein a reversible electric motor is provided to operate said flow divider valve and effect steering the vehicle, and

wherein manually operable means are provided to control energization of said motor.

16. The curb and gutter forming apparatus of claim 14,

wherein a reversible electric motor is provided to operate said variable flow divider valve, and

wherein automatic means are provided to control energization of said motor in accordance with the line of the roadway.

17. The curb and gutter forming apparatus of claim 16,

wherein the automatic means comprises a line extending along the line of the roadway,

a sensor engaging said line, and

electrical circuitry and control means between said line sensor and said electric motor and actuated by signals generated by said line sensor to energize said motor to operate said variable flow divider vale in accordance with deviation of the machine from said line and the line of the roadway.

18. The curb and gutter forming apparatus of claim 17,

wherein manual means are also provided to energize said electrical circuitry and control means to operable said motor, and vary the flow to said hydraulic motors in ac cordance with deviations from said line.

19. The curb and gutter forming apparatus of claim 9,

wherein individual fluid pressure operated motors are provided to drive said continuous traction tread devices,

wherein a variable flow divider valve is provided to divide the flow to said motors in accordance with the line of the roadway,

wherein a line sensor is provided to effect operation of said flow divider valve'to supply a uniform volume of fluid to each motor and to supply a greater volume of fluid to one motor than the other in accordance with the required line of travel of the apparatus 20. The curb and gutter forming apparatus of claim 19,

wherein a reversible motor is provided to operate said flow divider valve,

wherein said line sensor controls operation of said motor to vary the flow of fluid to said two motors, and

wherein a manually operated switch is provided and electrical control connections are provided between said switch and said reversible motor for effecting variation of said flow divider valve and manual steering of the machine.

211. In a steering assembly and in combination with a paving machine and the like,

a main frame,

laterally spaced continuous propelling said main frame,

an individual fluid pressure operated motor for driving each of said continuous traction tread devices,

a source of fluid under pressure,

a flow divider valve,

a fluid pressure connection from said source of fluid under pressure to said flow divider valve,

separate fluid pressure connections from said flow divider valve to each of said motors,

a reversible electric motor having operative connection with said flow divider valve, operating said valve to supply equal volumes to fluid to each hydraulic motor and to supply a greater volume of fluid to one motor than the other in accordance with the line of the roadway,

a sensor and signal generating device operated thereby in W accordance with a line extending along the roadway, for controlling operation of said motor and the line of travel of the machine,

a manually operable switch effective to connect said signal generating device in the operating circuit for said motor to effect automatic steering of the machine and to disconnect said signal generating device from said circuit to actraction tread devices commodate manual steering of the machine, and

a second manually operable switch effective to manually control said motor and effect manual steering of the machine.

22. in paving machine,

a main frame,

a pair of laterally spaced continuous traction devices,

a three-point suspension between said continuous traction devices and said main frame, for tilting and moving said main frame up and down to conform to the grade and contour of a roadway comprising,

two fluid pressure operated self-locking screw jacks suspending one side of said main frame from one continuous traction tread device,

a third fluid pressure operated self-locking screw jack suspending the opposite side of said frame from a second of said continuous traction tread devices,

individual rotary fluid pressure operated motors having direct driving connection with each of said screwjacks,

valve means supplying fluid under pressure to two of said motors on one side of said main frame to conform to the grade of the roadway, and

valve means supplying fluid under pressure to the third of said fluid pressure operated motors independently of said first mentioned valve means, to conform said main frame and traction tread devices to the transverse tilt of the roadway, and

stabilizing guide means connected between said main frame and the second of said continuous traction tread devices comprising, 7

a vertically extending hollow post mounted on said main frame, cooperating with and extending parallel to said third self-lockin screw jack andsipaced therefrom, a yoke transverse y pivoted to sm tread frame in spaced relation with respect to said screw jack, and a guide member telescopically mounted in said post, and secured to and extending upwardly of said yoke, and guiding said main frame for up and down movement relative to said third self-locking screw jack.

HMIHJI unuu

Claims

1. In a curb and gutter forming apparatus, the combination comprising, a main frame, a pair of laterally spaced continuous traction tread devices, a mold form, a suspension draft connection between said main frame and said mold form, accommodating said mold form to conform to the line of the roadway upon movement of the apparatus from straight line movement, comprising a drawbar at the front of said main frame, and a vertical pivotal connection suspending the front end of said mold frame from said drawbar, grade and slope conforming connections between said continuous traction tread devices and said main frame supporting said main frame on said traction tread devices and conforming said main frame and Mold form to various grades and lateral sloping conditions of the roadway.

2. The curb and gutter forming apparatus of claim 1, wherein a laterally slidable suspending connection is provided between said main frame and the rear end portion of said mold form accommodating limited lateral movement of the rear end portion of said mold form relative to the said main frame about said vertical pivotal connection.

3. The curb and gear forming apparatus of claim 2, wherein the suspension connection between the rear end of said main frame and said mold form adjacent the rear end thereof, a transverse bar forming a support for said rollers and accommodating said rollers to move therealong, and means limiting movement of said rollers along said bar.

4. The curb and gutter forming apparatus of claim 2, wherein a hopper extends upwardly of said mold form at the front end thereof and opens to the top of said main frame to supply concrete to said mold form, and wherein means are provided for varying the discharge of concrete from said hopper to said mold form.

5. The curb an gutter forming apparatus of claim 4, wherein said mold form has a front wall having an open portion at the bottom thereof, accommodating excess concrete to flow through said open portion, to be formed by said mold form upon advance of said main frame, and wherein means extend in advance of said front wall forwardly along opposite sides of said open portion, to confine excess concrete to said open portion upon advance of said mold form.

6. The curb ad gutter forming apparatus of claim 1, wherein a three-point suspension is provided between said main frame and said continuous traction tread devices, to conform to said main frame, continuous traction tread devices and mold form, to varying slopes and grades of the roadway.

7. The curb and gutter forming apparatus of claim 6, wherein the three-point suspension includes two fluid pressure operated jacks on one side of said main frame, and suspending a first continuous traction tread device from one side of said main frame, and a single fluid pressure operated jack on the opposite side of said main frame suspending the other continuous traction tread device from the other side of said main frame, and wherein means are provided to control the supply of fluid under pressure to said jacks in accordance with the slope and grade of the roadway.

8. The curb and gutter forming apparatus of claim 7, wherein said fluid pressure operated jacks each include a hydraulic motor, and a self-locking screw and nut operated thereby.

9. The curb and gutter forming apparatus of claim 7, wherein the two jacks on one side of said main frame are grade controlling jacks and each include a self-locking screw and nut, wherein an individual fluid pressure operated motor is provided for operating each of said jacks in accordance with the grade of the roadway, wherein the single jack on the opposite side of said main frame includes a self-locking screw and nut, wherein an independent fluid pressure operated motor is provided for operating said screw and nut, and wherein a vertical stabilizer guide is provided on the side of the main frame in association with said one jack, and is pivotally connected to the associated traction tread device and rigidly secured to said main frame to guide the associated traction tread device and accommodate the single jack to tilt said main frame laterally to conform to the transverse slope of the roadway.

10. The curb and gutter apparatus of claim 9 wherein a grade sensor is provided for each grade control jack to individually control operation of said grade controlling jacks, wherein said grade sensors are located adjacent the front and rear ends of said main frame, and wherein fluid pressure control means operated by signals generated by sad grade sensors are provided to independently supply fluid under pressure to said grade control jacks in accordance wIth the grade sensed by said grade sensors.

12. The curb and gutter forming apparatus of claim 10 wherein individual electrically energizable valve means are provided for each of said grade sensor jacks, and wherein an electrical energizing connection is provided between each of said grade sensors and an associated electrically energizable valve means, to effect the supply of fluid under pressure to said fluid pressure operated motors in accordance with the grade sensed, to rotate said motors in one direction or another or to hold said motors from rotation.

13. The curb and gutter forming apparatus of claim 12, wherein individual electrically energizable valve means are provided to control the supply of fluid under pressure to said third fluid pressure operated motor, and wherein a slope sensing control, sensing tilting of the apparatus about an axis extending longitudinally of said main frame is provided to control energization of said valve means, and the supply of fluid under pressure to said third fluid pressure operated motor, to effect rotation of said third fluid pressure operated motor in one direction or another, or to hold said motor from rotation in accordance with the slope of the roadway.

14. The curb and gutter forming apparatus of claim 1, wherein individual fluid pressure operated motors are provided to drive said traction tread devices, and wherein a variable flow divider vale is provided to supply fluid under pressure to said motors to effect steering by supplying a greater volume of fluid to one motor than to the other, and to supply an equal volume of fluid to each of said motors.

15. The curb and gutter forming apparatus of claim 14, wherein a reversible electric motor is provided to operate said flow divider valve and effect steering the vehicle, and wherein manually operable means are provided to control energization of said motor.

16. The curb and gutter forming apparatus of claim 14, wherein a reversible electric motor is provided to operate said variable flow divider valve, and wherein automatic means are provided to control energization of said motor in accordance with the line of the roadway.

17. The curb and gutter forming apparatus of claim 16, wherein the automatic means comprises a line extending along the line of the roadway, a sensor engaging said line, and electrical circuitry and control means between said line sensor and said electric motor and actuated by signals generated by said line sensor to energize said motor to operate said variable flow divider vale in accordance with deviation of the machine from said line and the line of the roadway.

18. The curb and gutter forming apparatus of claim 17, wherein manual means are also provided to energize said electrical circuitry and control means to operable said motor, and vary the flow to said hydraulic motors in accordance with deviations from said line.

19. The curb and gutter forming apparatus of claim 9, wherein individual fluid pressure operated motors are provided to drive said continuous traction tread devices, wherein a variable flow divider valve is provided to divide the flow to said motors in accordance with the line of the roadway, wherein a line sensor is provided to effect operation of said flow divider valve to supply a uniform volume of fluid to each motor and to supply a greater volume of fluid to one motor than the other in accordance with the required line of travel of the apparatus

20. The curb and gutter forming apparatus of claim 19, wherein a reversible motor is provided to operate said flow divider valve, wherein said line sensor controls operation of said motoR to vary the flow of fluid to said two motors, and wherein a manually operated switch is provided and electrical control connections are provided between said switch and said reversible motor for effecting variation of said flow divider valve and manual steering of the machine.

21. In a steering assembly and in combination with a paving machine and the like, a main frame, laterally spaced continuous traction tread devices propelling said main frame, an individual fluid pressure operated motor for driving each of said continuous traction tread devices, a source of fluid under pressure, a flow divider valve, a fluid pressure connection from said source of fluid under pressure to said flow divider valve, separate fluid pressure connections from said flow divider valve to each of said motors, a reversible electric motor having operative connection with said flow divider valve, operating said valve to supply equal volumes to fluid to each hydraulic motor and to supply a greater volume of fluid to one motor than the other in accordance with the line of the roadway, a sensor and signal generating device operated thereby in accordance with a line extending along the roadway, for controlling operation of said motor and the line of travel of the machine, a manually operable switch effective to connect said signal generating device in the operating circuit for said motor to effect automatic steering of the machine and to disconnect said signal generating device from said circuit to accommodate manual steering of the machine, and a second manually operable switch effective to manually control said motor and effect manual steering of the machine.

22. In paving machine, a main frame, a pair of laterally spaced continuous traction devices, a three-point suspension between said continuous traction devices and said main frame, for tilting and moving said main frame up and down to conform to the grade and contour of a roadway comprising, two fluid pressure operated self-locking screw jacks suspending one side of said main frame from one continuous traction tread device, a third fluid pressure operated self-locking screw jack suspending the opposite side of said frame from a second of said continuous traction tread devices, individual rotary fluid pressure operated motors having direct driving connection with each of said screw jacks, valve means supplying fluid under pressure to two of said motors on one side of said main frame to conform to the grade of the roadway, and valve means supplying fluid under pressure to the third of said fluid pressure operated motors independently of said first mentioned valve means, to conform said main frame and traction tread devices to the transverse tilt of the roadway, and stabilizing guide means connected between said main frame and the second of said continuous traction tread devices comprising, a vertically extending hollow post mounted on said main frame, cooperating with and extending parallel to said third self-locking screw jack and spaced therefrom, a yoke transversely pivoted to said tread frame in spaced relation with respect to said screw jack, and a guide member telescopically mounted in said post, and secured to and extending upwardly of said yoke, and guiding said main frame for up and down movement relative to said third self-locking screw jack.