US3466990A

US3466990A - Paving machine

Info

Publication number: US3466990A
Application number: US673398A
Authority: US
Inventors: Frank R Toles
Original assignee: GORDON H BALL Inc
Current assignee: GORDON H BALL Inc
Priority date: 1967-10-06
Filing date: 1967-10-06
Publication date: 1969-09-16
Anticipated expiration: 1986-09-16

Description

F. R. TOLES PAVING MACHINE Sept. 16, 1969 5 Sheets-Sheet 1 Filed Oct. 6, 1967 ATTORNEYS Sept. 16, 1969 Filed Oct. 6, 1967 F. R. TOLES 3,466,990

PAVING MACHINE 5 Sheets-Sheet 2 INVENTOR.

FRANK R. TOLES 45%, W m a/Mn WW ATTORNEYS F. R. TOLES PAVING MACHINE Sept. 16, 1969 5 Sheets-Sheet 5 Filed Oct. 6, 1967 INVENTOR.

FRANK R. TOLES 554i M WWW WWW ATTORNEYS Sept. 16, 1969 F. R. TOLES 3,466,990

PAVING MACHINE Filed Oct. 6, 1967 5 Sheets-Sheet L I (53 or 9 :LIO? 7 F I Tl Ii Z .210 yl-lxm Q INVENTOR.

FRANK R. TOLES F/G. 5 BY g/a fjf f ATTORNEYS Sept. 16, 1969 o s 3,466,990

PAVING MACHINE Filed Oct. 6, 1967 5 Sheets-Sheet 5 I V v I ooww l 2 I32 /|osb I080) |31 v THIN THICK V THIN THICK IO6b Z 1060 I070 (/snosab |o7b (66) 1090 IONS 03;

INVERT (g I NVENTOR.

7 FRANK R. TOLES BY 67%, wLM w m 4 97 ATTORNEYS United States Patent 3,466,990 PAVING MACHINE Frank R. Toles, Highland, Calif, assignor to Gordon H. Ball, Ina, Danville, Calif., a corporation of Nevada Filed Oct. 6, 1967, Ser. No. 673,398 Int. Cl. E01c 19/48 US. CI. 94-46 7 Claims ABSTRACT OF THE DISCLOSURE A machine having paving apparatus adjustably supported from wheels or tracks. Ground engaging sensors are supported by the apparatus and actuate an electrical circuit to generate control signals. The adjustable supports are responsive to the control signals to maintain the correct elevation of the paving apparatus and, therefore, thickness of the pavement.

BACKGROUND OF THE INVENTION This invention relates generally to a paving machine and more particularly to a paving machine having means for automatically controlling the thickness of the pavement.

Paving machines in which the thickness of pavement is automatically controlled are known in the art. One such machine includes paving apparatus supported from tracks. A grade wire is strung alongside the surface to be paved. A sensor mounted on the paving apparatus engages the wire and generates a signal when the paving apparatus is above or below the grade determined by the grade wire. Typical apparatus of this type is shown in Patent No. 2,864,452.

Machines of this type have been used to pave roadways, airport runways and the like. Paving machines have also been employed to pave the slope or side walls of canals.

Prior art apparatus of this type used to pave the walls of canals included grade wires strung parallel to the wall along the berm and invert of the canal. The thickness of the pavement was maintained only while the machine was moving in such a manner that the strike off for the concrete was moving substantially perpendicular to the line of travel. If any skew occurred, that is, one end of the machine was travelling faster or slower than the other end, the pavement thickness on the slope would deviate from the desired thickness even though the machine was properly tracking the grade wire.

SUMMARY OF THE INVENTION AND OBJECTS The present invention provides a machine which includes spaced supporting tracks or wheels which serve to adjustably support a paving apparatus. A skid or ski is supported from the apparatus and adapted to engage and slide on the finished grade in front of the machine. Means are associated with the skid whereby vertical movement of the skid with respect to the machine is converted into an electrical signal which is proportional to the off grade condition. The control signal serves to actuate an electrical or electro-pneumatic circuit which, in turn, controls the supporting means to raise and lower the paving apparatus to restore the correct grade.

It is an object of the present invention to provide a paving apparatus in which the grade is controlled by an electrical system including ground sensing means mounted on the apparatus.

It is another object of the present invention to provide a paving apparatus for use in paving canal walls in which control is switched from the invert to the slope when a slope detector shows that the thickness on the slope is 3,466,990 Patented Sept. 16, 1969 BRIEF DESCRIPTION OF THE DRAWING FIGURE 1 is a schematic perspective view showing a paving apparatus incorporating the present invention paving the walls of a canal.

FIGURE 2 is a top elevation of the apparatus shown in FIGURE 1.

FIGURE 3 is a sectional view taken along the line 3-3 of FIGURE 2.

FIGURE 4 is a sectional view taken along the line 44 of FIGURE 2.

FIGURE 5 is a sectional view taken along the line 5--5 of FIGURE 2.

FIGURE 6 is a schematic diagram of an attitude control circuit incorporating one aspect of the present invention.

FIGURE 7 is a schematic diagram of a thickness or grade control incorporating other aspects of the invention.

FIGURE 8 is an enlarged elevation view showing the lower attitude control arrangement associated with the invert portion of the machine.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGURES 1 and 2, the apparatus comprises spaced tracks 11 and 12 which serve to support the paving apparatus designated generally by the reference numeral 13. The paving apparatus is of a conventional design and includes a trough or hopper 14 into which concrete is conveyed. On a slope paver the concrete is introduced at the top and conveyed and distributed along the hopper. A strike-oil forms the rear wall of the hopper; a vibrator may compact the concrete just prior to the strike-off and suitable trowelling devices may trail the strike-off. Patent No. 2,864,452 shows and describes a typical paving apparatus.

The tracks 11 and 12 are self-propelled and serve to move the paving apparatus over the area to be paved. In the example shown above, the area 16 designates the area that has been levelled and graded to receive the pavement while the area 17 shows a paved area having embedded longitudinal and vertical joint forms 18 and 19.

The paving apparatus is supported from the tracks by four hydraulic rams, two located at each end of the apparatus, and designated generally by 21a, 21b and 22a, 22b. The rams may be electro-mechanical rather than hydraulic.

The apparatus carries an internal combustion engine such as a diesel engine which drives a hydraulic pump for supplying hydraulic fluid under pressure and an electrical generator for generating electricity, all shown generally by reference numeral 25. Hydraulic motors may be employed to power the tracks 11 and 12. Suitable control valves are provided in the hydraulic lines leading from the hydraulic pump to the rams to control the height or level of the paving apparatus and to the track motors to control the speed of the tracks for steering the apparatus.

In accordance with the present invention, there are provided ground engaging skis or skids suitably supported from the front of the apparatus. In the apparatus shown, there are three pairs of such skids, a first pair 26 engaging the slope near the top; a second pair 27 engaging the slope about two-thirds of the way down; and a third pair 28 engaging the invert. The mounting for each of the three pairs of skis is substantially identical and, therefore, the mounting for the upper pair of skis is described. The skis are each pivotally supported from a cross member 31 which is supported from the bottom of a scissor-like support 32, comparable to a scissor type jack. The top of the scissor-like support is attached to a projecting member 33 attached to a member 34 pivotally secured to the front of the apparatus. The distance between the cross bar 31 and the support 33 is controlled by rotating the crank 36 to rotate a screw 35 associated with the scissor jack for expanding or gontacting the cross members.

Referring now particularly to the upper pair of skis 26, the uppermost ski 41 is disposed in advance of the lower ski 42. A bracket 43 in the form of an inverted Y is suitably attached to the uphill ski 41. Thus, as the uphill ski moves up and down, pivoting about the point 40, the upper end of the bracket will move through an are designated by the arcuate arrow 44. A bracket 46 is attached to the support 34 and extends upwardly and likewise moves through an are designated by the reference numeral 47 as the vertical distance between the front of the apparatus and the pair of skis changes to pivot the member 34 about pivot point 45.

The upper end of the bracket 46 is attached to one end of a spring 51. The other end of the spring is attached to one end of chain 52. The other end of the chain is attached to arm 53 of a potentiometer 54 to vary the resistance of the potentiometer responsive to movement of the bracket.

The upper end of the bracket 43 is likewise secured to a spring 56, in turn, secured to a chain 57 which activates arm 58 of another potentiometer 59.

As will be presently described, the potentiometer 54 forms part of an electrical circuit which controls the attitude of the apparatus, while the potentiometer 59 forms part of an electrical circuit which serves to control the elevation of the paving apparatus and, in turn, the thickness of the pavement.

Referring to FIGURE 4, the skis 27 are supported in the manner described above with reference to FIGURE 3 and like parts bear similar numbers with the sufiix a. A bracket 61 is mounted on member 34a. It moves through an are 62 in response to pivotal movement about point 60 resulting from relative movement of the skis and paving apparatus. The upper end of the bracket is connected to a spring 63 which is, in turn, connected to chain 64 for activating the arm 66 of a potentiometer 67. Counterbalance means are provided at the top of the bracket 61 for providing a lifting force in the counter-clockwise direction. Such means comprises a chain 70 which is reeled over a pulley 68 and provided with a weight 69.

The pair of skis 28 are mounted in a similar manner and like reference numerals bearing the suflix b are applied to like parts by pivoting about chain 70. A bracket 71 is provided and moves through an arc 72. A spring 73 and chain 74 are secured between the upper end of the bracket and the arm 76 of a potentiometer 77. A counter-balance is provided by the combination of chain 78 secured to bracket 71, reeled over the pulley 79, and secured to weight 81.

An attitude control is associated with the invert portion of the machine. The invert attitude control comprises a first upstanding member 82 secured to the back of the apparatus for movement therewith and a second upstanding member 83 is secured to the tracks. A change in attitude (roll or pitch) of the paving apparatus will increase or decrease the distance between the upper ends of the

upstanding brackets

82 and 83. A cable 84 and springs 86 and 87 are attached between the upper end of bracket 82 and arm 88 of potentiometer 89. Range adjustment means 91 as, for example, a screw adjustment, is provided for increasing or decreasing the length of the cable to thereby adjust the range of attitude control. The electrical circuit associated with the potentiometer is similar to the circuit associated with the upper ski to be presently described.

Thus, it is seen that as the machine moves forward, the various skis engage the ground and, depending upon the elevation of the machine and the finished grade, it will move up an down relative to the machine, in turn moving the associated brackets which serve to vary the associated potentiometer. The amount of variation is directly related to the relative elevation of the skis and the apparatus.

The two attitude controls, although different in their mechanical attachment to the machine, have identical electrical control circuits. One control circuit is shown in FIGURE 6. The circuit comprises a resistance bridge with a first pair of legs of the bridge formed by the portions 101 and 102 of the resistor designated generally by the number 103, and a second pair formed by portions 106 and 107 of resistance 108. One end of the resistors is grounded while the other end is connected to a voltage V. Variable taps or

arms

104 and 109 determine the relative magnitude of the resistances in the

arms

101, 102 and 106, 107 respectively. The arm or tap 109 corresponds to the

arms

53 or 88 referred to above with respect to the upper and lower attitude controls shown in FIGURES 3 and 8, respectively. A control circuit is connected across the

arms

104 and 109. The control circuit includes a meter relay 111 having its driving coil connected in series with a variable resistor 112 and the parallel combination of oppositely poled

diodes

113, 114 and relay coils 116 and 117, respectively. The coils actuate

contacts

118 and 119 connected in series with lights 121 and 122. When the contacts are closed, the lights are illuminated or energized.

The meter relay 111 may, for example, comprise a zero center meter which is provided with contacts associated with the pointer 127 whereby when the current through the coil is above or below a preset amount, set by moving the contacts, electrical connection is made between the pointer and the associated

lines

128 or 129, in turn. The

lines

128 and 129 are connected to relay

coils

131 and 132, respectively, which then serve to activate

relay contacts

133 and 134. The

contactors

133 and 134 serve to energize a two-way electromagnetic valve connected to control hydraulic fluid to the associated front adjustable support 21a or 22a to thereby raise or lower the front of the apparatus to correct the attitude.

With the machine in the proper attitude, the zero adjust 104 is moved until the pointer 127 is in the center of the scale. Then, if the attitude of the machine changes, the contactor 109 will move in one or the other direction and the needle will move correspondingly. When the attitude has exceeded a predetermined amount, either tilting forward or tilting back, the needle will contact the contactor and energize the associated relays 131 or 132 to raise or lower the front of the apparatus by raising or lowering the rams.

The resistor 112 is employed to adjust the sensitivity of the bridge circuit. By introducing more resistance in series with the meter coil, the circuit becomes less sensitive and a greater current is required to close the contacts while decreasing the resistance which provides for an increased sensitivity. As a result, the device can be adjusted to close the contacts on any predetermined amount of motion of the skis relative to the paving apparatus.

The individual elevation control circuits associated with the potentiometers for the upper slope skis, lower slope skis, and invert

skis

26, 27 and 28, respectively, are each connected in a resistive bridge circuit which is substantially identical to that described above. Two-way solenoid valves are associated with the circiut for the upper elevation control and serve to control the hydraulic fluid to the upper front hydraulic ram 22a to raise or lower the apparatus as required. The elevation controls for the lower slope skis and the invert skis are shown in FIGURE 7. In This figure, elements which correspond in operation to those described with respect to FIGURE 6 bear like reference numerals. However, the sufiixes a and b are added to the numbers to identify the slope and invert controls respectively. Operation of the circuit is substantially as previously described.

There is provided a control circuit which serves to transfer control of the lower forward ram 21a between the lower slope control circuit and the invert control circuit. The control is transferred to the slope control if the pavement on the slope is out of specification, that is, too thin or too thick for a predetermined period of time. After the apparatus has returned to the proper elevation for a predetermined period of time, the control for the lower ram 21a is again transferred to the invert control circuit.

The transfer circuit is now described. One set of relay contacts 118:: and 119a is connected in series with the coil 135 between the voltage V and ground. When either of these contacts is closed, current will flow through the coil 135. The relay coil 135 is of the time delay type having an adjustable delay between, say, zero and seconds. If the current flows for the predetermined set time, the contact 135a associated with the coil will close to connect the voltage V to the coil 140 and to the indicating light 137. When the coil 140 is energized, it will also close a pair of contacts 139 which activate the coil 141 to throw the relay armature 142 to the contact 143 thereby connecting the control meter 111:: into the circuit for controlling the

coils

131 and 132 which control the two-way hydraulic valve associated with the front ram 121a of the invert. Control then remains with the lower slope control until the correct elevation of the apparatus is achieved.

Thereafter, control is transferred to the invert slope control. Control is transferred back because the current through the

coils

116a and 117a is reduced and the associated contacts 118a or 119a open thereby deenergizing the relay 135 and returning the circuit to its original state I claim:

1. In a paving machine of the type including mobile spaced support means, a paving apparatus and means for adjustably supporting the paving apparatus on each of said support means whereby it can be raised and lowered to control the thickness of the pavement, the improvement including means for controlling the pavement thickness comprising means for engaging and riding on the surface to be paved, means for mounting said engaging means on said paving apparatus for independent vertical movement with respect thereto, an electrical circuit including a variable electrical element, said electrical circuit serving to generate a control signal when the variable element is varied beyond a predetermined amount, means for actuating said variable element responsive to vertical movement of said engaging means with respect to said apparatus whereby to generate a control signal when there is a predetermined vertical movement of said surface engaging means with respect to said paving apparatus, and means responsive to said control signal for controlling said means for adjustably supporting the paving apparatus to reestablish the vertical relationship between said surface engaging means and the paving apparatus.

2. A paving machine as in claim 1 which includes means for controlling the pavement thickness at each end of said machine to ride on the surface adjacent each end of the machine and to control the associated adjustable support means to provide thickness control at each side edge of the pavement.

3. A paving machine as in claim 2 adapted to pave the sloping walls of a canal with one spaced support means travelling on the berm and another on the invert whereby the means for controlling the pavement thickness disposed at one end is near or at the berm and the other is near or at the invert, including an additional means for controlling the pavement thickness disposed between said two thickness control means to ride on the wall to be paved, and means for transferring control of the invert adjustable support means from the other thickness control means at or near the invert to the additional means responsive to a predetermined relative movement between the additional means for controlling the pavement thickness and the paving apparatus and back, when the movement is less than said predetermined movement.

4. A paving machine as in claim 1 wherein the electrical circuit comprises a bridge circuit having a voltage applied across a first pair of opposite bridge terminal, the magnitude of said voltage being dependent upon the variation of said variable element, and means connected across the other pair of opposite bridge terminals for generating said control signal.

5. A paving machine as in claim 4 wherein said last named means comprise a meter relay.

6. A paving machine as in claim 2 which includes attitude control means connected to the means for adjustably supporting the paving apparatus to provide attitude control at each end of the apparatus.

7. A paving machine as in claim 3 which includes attitude control means connected to the means for adjustably supporting the paving apparatus to provide attitude control at each end of the apparatus.

References Cited UNITED STATES PATENTS 2,844,882 7/1958 Earley. 3,230,846 1/1966 Curlett 9446 3,236,163 2/ 1966 Ackerman 9446 3,247,771 4/1966 Hanson 9446 3,354,801 11/1967 Hanson 9444 XR 3,264,958 8/1966 Babb et al 9446 FOREIGN PATENTS 1,095,178 12/1954 France.

JACOB L. NACKENOFF, Primary Examiner