Screed attached grade reference mechanism

Claim 2

In a paving machine of the type having a screed which is pulled at the rear of the machine by a pair of draft arms, the forward ends of said draft arms being pivotally engaged with the machine, wherein powered actuating means are provided for varying the angle of attack of the screed, and wherein a control system operates said powered actuating means in response to movement of a grade reference sensor, the improvement comprising: a. a mobile grade reference device elongated longitudinally in the direction of travel of the paving machine; b. a grade reference beam extending longitudinally of the direction of travel of the paving machine; c. rigid connecting means securing the forward end of said beam to said grade reference device intermediate the ends thereof such that vertical movements of the latter are directly transmitted to the former whereby said forward end of said beam and the portion of said grade reference device adjacent said connecting means move vertically in unison, said rigid connecting means including first horizontal pivot means pivotally connecting said forward end of said beam with said grade reference device and defining a horizontal pivot axis located rearwardly of the pivot axes of the draft arms; d. second horizontal pivot means pivotally connecting the rearward end of said beam with the screed; e. support means mounting said sensor for movement with the screed and at a location intermediate the ends of said beam; and f. said beam including an element engaged by said sensor for moving the latter thereby to activate said control system in response to relative vertical displacements between said mobile grade reference device and said screed.

Claim 3

The improvement according to claim 1 further defined by said connecting means mounting said mobile grade reference device forwardly of said screed and within the lateral extremities thereof, said first pivot means including a member connected to said mobile grade reference device adjacent the longitudinal midpoint thereof, and said sensor being located adjacent the longitudinal midpoint of said beam.

Claim 4

The improvement according to claim 1 wherein said second pivot means pivotally connects said beam with the screed adjacent the rearward portion of the latter.

Claim 5

The improvement according to claim 1 wherein said support means mounts said sensor forwardly of the forward portion of the screed and adjacent thereto.

Claim 6

The improvement according to claim 1 wherein said element is defined by a stringline on said beam.

Claim 7

The improvement according to claim 2 further defined by, said second pivot means including a member rigidly connected to said screed and upstanding therefrom so as to cooperate witH said rigid connecting means to mount said beam in substantial horizontal disposition and at an elevation above said screed.

Claim 8

The improvement according to claim 6 wherein said one member of said second pivot means is connected to said screed adjacent the rearward portion thereof.

Claim 9

The improvement according to claim 2 further defined by, said mobile grade reference device including a plurality of longitudinally extending articulated arms supported from plural subgrade engaging members.

Claim 10

In a paving machine of the type having a screed which is pulled at the rear of the machine by a pair of draft arms, the forward ends of said draft arms being pivotally engaged with the machine, wherein powered actuating means are provided for varying the angle of attack of the screed, and wherein a control system operates said powered actuating means in response to movement of a grade reference sensor, the improvement comprising: a. a mobile grade reference device including a plurality of articulated arms supported by plural subgrade engaging members, which arms extend longitudinally of the direction of travel of the paving machine; b. means connecting said mobile grade reference device to the paving machine for movement therewith and in a position forward of the screed and within the lateral extremities thereof; c. a grade reference beam extending longitudinally of the direction of travel of the paving machine; d. rigid connecting means securing the forward end of said beam to said grade reference device intermediate the ends thereof such that vertical movements of the latter are directly transmitted to the former whereby said forward end of said beam and the portion of said grade reference device adjacent said connecting means move vertically in unison, said rigid connecting means including first horizontal pivot means pivotally connecting said forward end of said beam with said grade reference device and defining a horizontal pivot axis located rearwardly of the pivot axes of the draft arms; e. second horizontal pivot means pivotally connecting the rearward end of said beam with said screed; f. support means mounting said sensor for movement with the screed and at a location intermediate the ends of said beam; and g. said beam including an element engaged by said sensor for moving the latter thereby to activate said control system in response to relative vertical displacements between said mobile grade reference device and said screed.

Claim 11

In a paving machine of the type having a screed which is pulled at the rear of the machine by a pair of draft arms, the forward ends of said draft arms being pivotally engaged with the machine, wherein powered actuating means are provided for varying the angle of attack of the screed, and wherein a control system operates said powered actuating means in response to movement of a grade reference sensor, the improvement comprising: a. a mobile grade reference device including a plurality of articulated arms supported by plural subgrade engaging members, which arms extend longitudinally of the direction of travel of the paving machine; b. means connecting said mobile grade reference device to the paving machine for movement therewith and in a position forward of the screed and within the lateral extremities thereof; c. a grade reference beam extending longitudinally of the direction of travel of the paving machine; d. rigid connecting means securing the forward end of said beam to said grade reference device intermediate the ends thereof such that vertical movements of the latter are directly transmitted to the former whereby said forward end of said beam and the portion of said grade reference device adjacent said connecting means move vertically in unison, said rigid connecting means including first horizontal pivot means pivotally connecting said forward end of said beam with said grade reference device and defining a horizontal pivot axis located rearwardly of the pivot axes of the draft arms; e. second horizontal pivot means pivotally connecting the rearward end of said beam with said screed; f. support means mounting said sensor for movement with the screed and at a location intermediate the ends of said beam; and g. said beam including an element engaged by said sensor for moving the latter thereby to activate said control system in response to relative vertical displacements between said mobile grade reference device and said screed.

Claim 12

The improvement according to claim 9 wherein said support means mounts said sensor forwardly of the forward portion of said screed and adjacent thereto and at a location adjacent the longitudinal midpoint of said beam.

Claim 13

The improvement according to claim 10 wherein said second pivot means connects said beam to said screed adjacent the rearward portion of the latter.

Claim 14

The improvement according to claim 11 wherein said element on said beam is engaged by said sensor adjacent the longitudinal midpoint of said beam.