Screed extension device

BACKGROUND OF THE INVENTION

Machines for laying pulverant material such as hot asphalt on the ground are commonly employed. These machines normally are constructed so as to include a hopper for receiving the pulverant material to be layed upon an earth’s surface. In such machines normally the hopper discharges into a distribution chamber where the material received from the hopper is spread out over the surface to receive this material. Frequently such a distribution chamber contains an auger or similar structure which is intended to equalize the quantities of pulverant material deposited by such a machine throughout a width corresponding to the width of the machine.

A machine of this type normally includes what is referred to as a screed or screed member at the rear of the distribution chamber for leveling of the pulverant material deposited in the distribution chamber. Frequently such a screed or screed member is formed so as to tamp or otherwise tend to compact material deposited. Whenever machines of the type indicated are used, however, certain problems are often apparent.

These problems concern the width of the strip of pulverant material which can be deposited. In general with such machines the width of such a strip corresponds to the width of the distribution chamber. Normally such machines are constructed so that this is the width of the machine itself. With such machines it is impossible to normally lay down a strip of pulverant material which is comparatively narrow and/or to lay down a strip of material which is only slightly wider than the width of the distribution chamber. Frequently situations are encountered where machines are used to lay down a layer of asphalt adjacent to a curb where the areas to be covered are of an irregular width and are only slightly larger than the width of the machine. A single pass of a conventional machine in these circumstances will leave an area upon which the asphalt is not deposited which is sufficiently narrow so that the paving machine cannot be used to lay it down. As a result, frequently the asphalt required in such an area has to be filled in by hand. This is laborious and expensive.

BRIEF DECRIPTION OF THE INVENTION

This invention is concerned with screed extension devices which can be used on existing machines for laying down a layer of pulverant material such as so-called paving machines for depositing a layer of hot asphalt. With the present invention the screed extension devices are constructed in such a manner that they may be attached to and form a part of the screed or screed member in such a machine. If desired they may be integrally constructed as a part of such a machine.

In addition, the devices of the invention are constructed in such a manner as to be capable of being operated during the operation of such a machine so that the machine itself can be used to lay down a strip of constant or varying width which is slightly larger than the strip of pulverant material which can be deposited by such a machine normally. These screed extension devices of this invention are capable of being used at only one side or on both sides of a machine for depositing a layer of pulverant material depending upon a user’s desires.

From this it will be apparent that an objective of this invention is to provide screed extension devices which can be used on existing machines for depositing a layer of pulverant material of such a nature that a larger strip of such material can be deposited with these machines than formerly possible and of such a nature that the width of the strip of material deposited may be continuously varied as required, as, for example, when laying pulverant material adjacent to an irregular boundary for such material. Further objects of this invention are to provide screed extension devices of the type described which may be manufactured at a comparatively nominal cost, which may be easily and conveniently used and which are capable of giving prolonged, effective performance. !

Each of the screed extension devices of this invention has a unit which includes a mounting member adapted to be mounted at the rear of a distribution chamber in a machine for depositing hot asphalt, a cut-off or strikeoff plate and an end plate assembly movably mounted on the mounting member so as to be capable of being moved with respect to the distribution chamber and means for moving this assembly with respect to the mounting member. When a device such as this is used, the end plate in effect becomes an end member for the distribution chamber. Preferably two of the units are used together in a complete device of this invention, one at each end of a machine for discharging pulverant material, and the two members are attached by a common mounting.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details of this invention, as well as many advantages of it, will be apparent from the accompanying drawing in which:

FIG. 1 is a top plan view of a presently-preferred embodiment or form of a screed extension device of the present invention employing two separate screed extension units joined by a common member;

FIG. 2 is a front elevational view of the device shown in FIG. 1;

FIG. 3 is a fragmentary enlargement of the left half of the device shown in the preceding figures;

FIG. 4 is a cross-sectional view taken at line 4—4 of FIG. 3;

FIG. 5 is a cross-sectional view taken at line 5—5 of FIG. 3; and

FIG. 6 is a fragmentary enlargement of a portion of FIG. 5.

The phantom lines shown in FIG. 1 and FIG. 2 illustrate a portion of a conventional machine for depositing a layer of pulverant material with which the illustrated screed extension device is used.

The illustration of a presently-preferred embodiment or form of the screed extension device of this invention

3,572,227 is not to be taken as limiting the invention in any respect. It will be realized that various changes and modifications may be made in the precise device shown through the use or exercise of routine engineering skill.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the drawing there is shown a screed extension device 10 installed upon a rear surface 12 of a distribution chamber 14 within a conventional machine 16 for laying down a pulverant layer such as hot asphalt. Because machines such as the machine 16 are conventional and well known, details of this machine are not illustrated. It is to be understood that the machine 16 will normally include a hopper or related structure for receiving pulverant material for discharging this material into the chamber 14.

It will be understood that this chamber 14 will normally include a screw or auger or other equivalent structure for distributing pulverant material between the sides 18 of the chamber 14 and of the machine 16 upon a ground surface underneath the chamber 14 as the machine 16 is advanced in a forward direction. At the rear of the chamber 14 the machine 16 includes a conventional screed or screed member 20 which tends to smooth out any material deposited. Such a screed or screed member 20 may and normally is constructed so as to tamp the deposited material.

The device 10 includes an elongated, L-shaped, structural member 22 which extends between the sides 18 of the chamber 14 when installed in place on the rear surface 12. In the drawing no fastenings are shown for securing the structure from the member 22 in place on the member 12. It is to be understood that conventional fasteners such as bolts may be easily employed for this purpose.

At each of the ends of the member 22 a screed extension unit 24 is mounted by means of two bolts 26 to the member 22. The heads of these bolts 26 are secured in any convenient manner to mounting housings 28 of a generally rectilinear shape so that the bolts 26 themselves extend through the member 22. These bolts 26 are secured in place by nuts 30 in effect serving as hangers.

Preferably these bolts 26 carry between the housings 28 and the member 22 protective angle-shaped brackets 32. These brackets 32 are secured in place in a fixed, spacial relationship with respect to the housing 28 by means of other nuts 34. With this construction the relative spacing between the member 22 and the housings 28 can be adjusted through adjustment of the nuts 30. The housings 28 also carry lower slotted brackets 36 which are adapted to be secured to the rear surface 12 by means of other conventional fasteners such as bolts 38.

Each of the units 24 includes an assembly of a cutoff or strike-off plate 40 and an end plate 42. Each end plate is attached to the corresponding strike-off plate 40 so as to extend from it at a substantially right angle. Each of the end plates 42 may be provided with slots 44 adjacent to its lower edge 46 for use with conventional fasteners 48 such as bolts in adjustably securing a footlike lower extension 50 in place. Such extensions 50 may be used when necessary because of the vertical height of the machine 16.

Each of the strike-off plates 40 is provided with a top flange 52 and a central surface 54 dimensioned so that this flange 52 and surface 54 will fit between the bracket 32 and the housing 28 in such a manner that the bracket 32 and the housing 28 will act essentially as a track so as to guide or control the motion of the strike-off plates 40. This enables the strike-off plates 40 to be moved linearlly along the length of the housings 28 so that these strike-off plates 40 overlay the housings 28 with the end plates 42 substantially flush with the ends of the housings 28 or so that the strike-off plates 40 extend from the housings 28 well beyond the sides 18 in the machine 16.

When so constructed the cut-off plates 40 operate as extensions of the screed member 20. It will be noted that the surfaces 54 of the strike-off plates 40 overlay closely to the housings 28. The lower portions 56 of the cut-off plates 40 are curved so as to extend at an angle to the screed members 20 so that the entire strike-off plates 40 terminate at lower edges 57 located closely adjacent to the screed member 20. This effectively tends to preclude any accumulation of material between the cut-off plates 40 and the screed member 20. The shape of these cut-off plates 40 is also considered to tend to promote satisfactory deposition of material during the use of the machine 16 and the device 10.

Preferably the edges 57 of the strike-off plates 40 are parallel to and spaced slightly above the lower edge 58 of the screed member 20. This allows for the deposition of a greater height of material beyond the sides 18 of the machine 16 than in the area traversed by the screed member 20. When the screed member 20 is of a conventional tamping type, this provides an excess of material at the sides 18 of the machine 16 which can be compacted to substantially the same height as the material layed down in the area traversed by this screed member 20.

In each of the units 24, the assembly of the plates 40 and 42 is movably mounted so as to be capable of motion as previously described through the use of telescoping tubes 60 and 61 mounted on the end plates 42 and within the housings 28. These telescoping tubes 60 and 61 in effect act as stabilizers so as to also guide or control the motion of the strike-off plates 40 in a linear path. The tubes 60 are located on the plates 42 and are secured to these plates 42 at their ends whereas the tubes 61 are secured to the interiors of the housings 28 at their exteriors by any convenient means, such as welding. It will be noted that the tubes 60 are isolated from the distribution chambers 14 by means of the cut-off plates 40.

Relative motion between the housings 28 and the assemblies of the cut-off or strike-off plates 40 and the end plates 42 in each of the units 24 is accomplished through the use of conventional hydraulic cylinders 62. These cylinders 62 are attached to the housings 28 in a conventional manner by way of fasteners 66. The piston rods 68 extending from the cylinders 62 attached to the end plates 42 by brackets 70.

Conventional hydraulic lines 72 are used to control the operation of these cylinders 62 through the use of appropriate conventional hydraulic means (not shown). With this type of control the cylinders 62 in the units 24 can be concurrently operated or they can be operated independently of one another. As a result of this it is possible to utilize the screed extension units 24 at either side 18 of the machine 16 so as to lay down strips of uniform or varying widths as may be required or desirable.

As the complete device 10 is used the end plates 42 in the screed extension units 24 in effect form or define the ends of the chamber 14. Normally in such a chamber there is adequate material distribution so that during operation the amount of material located against the units 24 is substantially constant, regardless of whether these units 24 are retracted to a point where the end plates 42 are at the sides 18 or whether these units 24 are extended so that the end plates 42 are spaced a reasonable distance from the sides 18.

From a detailed consideration of the aforegoing, it will be apparent that the complete device 10 is very advantageous for certain types of use and that it adds materially to the utility of different types of machines such as the machine 16. It will be apparent that only a single one of the units 24 need be employed to gain advantages in accordance with this invention, but that maximum improvement on machines such as the machine 16 can be made with the complete device 10.