Asphalt paver with telescoping screed

• US 4,379,653 A
• Filed: 06/01/1981
• Issued: 04/12/1983
• Est. Priority Date: 06/01/1981
• Status: Expired due to Term

• Current Assignee: Blaw-Knox Construction Corporation
• Original Assignee: White Consolidated Industries Incorporated
• Inventors: Brown, Robert L.
• Primary Examiner(s): Byers, Jr., Nile C.
• Application Number:
  US06/269,383
• Time in Patent Office: 680 Days
• Field of Search: 404/104, 404/101, 404/79, 404/95, 404/118, 404/119, 280/781
• US Class Current: 404/118
• CPC Class Codes: E01C 19/4853 Apparatus designed for railless operation, e.g. crawler-mounted, provided with portable trackway arrangements
• CPC Class Codes: E01C 2301/10 Heated screeds
• CPC Class Codes: E01C 2301/16 Laterally slidable screeds

Abstract

The disclosure relates to a floating screed type asphalt paver provided with extendable, retractable auxiliary screed units which, in their retracted positions, are mounted in front of the main screed and carry edger plates. By mounting the screed extensions in front of the main screed units, it is possible to retract the extension units without interrupting paving operations. A strike-off plate may be positioned in front of the extension units to limit the presence of paving material between them and/or the extension units may be provided with bevelled inner edges for displacing such material during retraction. Novel arrangements are provided for mounting and adjusting the screed extensions.

Claims

1. A screed assembly for a floating screed asphalt paving machine, which comprises

(a) first and second main screed units, each including a front plate and a sole plate,

(b) screed extension units for each of said main screed units, each including a front plate and a sole plate,

(c) means for mounting said screed extension units in front of said main screed units, with the front plates of said extension units being positioned a substantial distance forwardly of the main screed units and the sole plates of said screed extension units extending rearwardly substantially to the front plates of said main screed units,

(d) said mounting means including, for each said extension unit, a pair of spaced guide rods mounted on said screed extension units and extending laterally substantially from one end to the other thereof, and a pair of guide sleeves slideably engaging said guide rods,

(e) said guide sleeves forming part of a support bracket assembly mounted at the front of a main screed unit,

(f) means for effecting vertical adjustment of said support bracket assembly relative to the main screed or screed extension unit, whereby to effect vertical adjustment of said screed extension unit with respect to the main screed unit,

(g) controllable positioning means for effecting controlled lateral extending and retracting movements of the screed extensions, and

(h) clearing means for preventing the accumulation of excessive amounts of paving materials between said screed extensions during retracting movements while paving, such that extending or retracting adjustments of said screed extension units may be effected at any time.

2. A screed assembly according to claim 1, further characterized by said clearing means comprising

(a) a strike-off plate means positioned in front of said screed extension units and supported from behind by the respective front plates thereof,

(b) said screed extension units being movable laterally independently of said strike-off plate means.

3. A screed assembly according to claim 2, further characterized by

(a) strike-off support arms mounted on said main screed units and extending forwardly to the front of said screed extension units, and

(b) strike-off adjustment means connecting said support arms and said strike-off plate means for effecting vertical adjustment thereof.

4. A screed assembly according to claim 3, further characterized by

(a) said strike-off plate means including a separate strike-off plate mounted by each of said main screed units,

(b) one of said strike-off plates at least partially overlapping the other.

5. A screed assembly according to claim 4, further characterized by

(a) a strike-off auxiliary back support extending forward from one of said main screed units and engaging the rear surface of said other strike-off plate to provide enhanced support when said screed extension units are laterally extended.

6. A screed assembly according to claim 1, further characterized by

(a) said clearing means comprising upwardly and inwardly bevelled bottom surface portions of said screed extensions joining the sole plates thereof at the inner ends of said screed extensions whereby at least limited quantities of paving material are directed underneath the screed extensions during retraction thereof while paving.

7. A screed assembly according to claim 6, further characterized by

(a) said assembly including strike-off plate means in accordance with claim 2.

8. A screed assembly according to claim 6, further characterized by

(a) said clearing means further including rearwardly and inwardly bevelled front surface portions of said screed extensions joining the front plates thereof at the inner ends of said screed extensions.

9. A screed assembly according to claim 1, further characterized by said means for effecting vertical adjustment of said support brackets comprising

(a) a positioning plate mounted on the back side of the main screed front plate,

(b) means for adjusting the angular orientation of said positioning plate relative to said main screed,

(c) connecting means extending through said main screed front plate and securing said support bracket assembly to said positioning plate, and

(d) means for moving said support bracket assembly in a generally vertical direction relative to said positioning plate.

10. A screed assembly according to claim 9, further characterized by the means for moving said support bracket assembly comprising

(a) a pair of support pins engaging said support bracket assembly and extending through said main screed front plate,

(b) a pair of scissors levers pivoted on said positioning plate and engaging said support pins, and

(c) actuator means mounted on said positioning plate and engaging said scissors levers,

(d) said actuator means being adapted for controlled actuation to effect controlled adjustment of said support bracket assembly in a generally vertical direction.

11. A screed assembly according to claim 10, further characterized by

(a) said actuator means including a generally vertically disposed linear actuator mounted on said positioning plate,

(b) said scissors levers being connected at their adjacent ends to said linear actuator,

(c) said scissors levers being pivotally connected intermediate their ends to said positioning plate, and

(d) said scissors levers being connected at their far ends to said support bracket assembly.

12. A screed assembly for a floating screed asphalt paving machine, which comprises

(a) first and second main screed units, each including a front plate and a sole plate,

(b) screed extension units for each of said main screed units, each including a front plate and a sole plate,

(c) means for mounting said screed extension units in front of said main screed units, with the front plates of said extension units being positioned a substantial distance forwardly of the main screed units and the sole plates of said screed extension units extending rearwardly substantially to the front plates of said main screed units,

(d) clearing means for preventing the accumulation of excessive amounts of paving material between said screed extensions during retracting movements while paving, such that extending or retracting adjustments of said screed extension may be effected during paving,

(e) means in the bottom area of said main screed units forming a heating chamber,

(f) means to supply hot gases to said heating chamber,

(g) gas outlet means for said heating chamber,

(h) a secondary heating chamber in each of said screed extension units,

(i) each said secondary heating chamber having an inlet aligned generally with said gas outlet means in certain predetermined positions of alignment of said main screed units and said screed extension units.

13. A screed assembly for a floating screed asphalt paving machine, which comprises

(a) first and second main screed units, each including a front plate and a sole plate,

(b) screed extension units for each of said main screed units, each including a front plate and a sole plate,

(c) means for mounting said screed extension units in front of said main screed units, with the front plates of said extension units being positioned a substantial distance forwardly of the main screed units and the sole plates of said screed extension units extending rearwardly substantially to the front plates of said main screed units, and

(d) edger plates mounted on said screed extension units and extending forward therefrom and below the level of the sole plates thereof.

14. A screed assembly according to claim 13, further characterized by

(a) strike-off plate means mounted directly in front of said screed extension units, when retracted, and serving to limit the presence of paving material between said extension units when said units are in extended positions.

15. A screed assembly according to claim 13 and/or 14, further characterized by

(a) said screed extensions having upwardly and inwardly bevelled bottom surface portions at the inside edge extremities thereof.

16. A screed assembly according to claim 13, further characterized by

(a) said screed extension having upwardly and rearwardly bevelled surface portions at their inner end extremities joining the respective sole plates and front plates thereof.

17. A screed assembly according to claim 16, further characterized by

(a) an hydraulic cylinder mounted on each of said main screed units and connected to the respective screed extension unit,

(b) said hydraulic cylinders each having a cylinder body extending toward the center of the screed assembly, and

(c) housing means covering those portions of the cylinder bodies that are exposed to paving material upon lateral extension of said screed extension units.