A plurality of fluid pressure cylinders (32, 33) are connected in parallel between one output port (19) and the other output port (20) of a changeover valve (15) which directionally controls a working fluid fed from a fluid pressure pump (12). A pilot check valve (34), together with the fluid pressure cylinder (32), is connected in parallel to the output port (19) of the changeover valve (15). A pilot signal pressure delivered from the fluid pressure cylinder (32) by the extending operation of the fluid pressure cylinder (32) actuates the check valve (34) for communication so as to feed working fluid to the fluid pressure cylinder (33). A pilot check valve (36), together with the fluid pressure cylinder (33), is connected in parallel to the output port (20) of the changeover valve (15). A pilot signal pressure delivered from the fluid pressure cylinder (33) by the contracting operation of the fluid pressure cylinder (33) actuates the check valve (36) for communication so as to feed working fluid to the fluid pressure cylinder (32).

Sequence control circuit

The invention discloses a method and system for controlling an ironing board of a paver. The paver comprises a main machine, a hydraulic system and the ironing board which is controlled and driven by the main frame; the paver is also equipped with a signal detection device used for detecting the type of the ironing board and generating a detection signal presenting the type of the ironing board. The method comprises the following steps: the main machine receives the detection signal generated by the signal detection device, judges whether the ironing board is a mechanical ironing board or a hydraulic expansion-type ironing board, and controls the hydraulic system to be in a corresponding work mode according to the judged result. Through the invention, the problem that after the expansion-type ironing board is converted into the mechanical ironing board, the hydraulic system for controlling the expansion of the ironing board is in an overflow state for a long time due to misoperation is solved, and the abnormal heating and the extra energy loss are guaranteed not to be caused due to the misoperation of the hydraulic system.

Method and system for controlling ironing board of paver

A screed for a paver finisher of the type comprising sectors (1c, 1d), independently extendible and retractable, substantially sliding on guides connected to the support arms (4a, 4b) respectively, in turn solid with the central screed fixed sectors (1a) and (1b) respectively, said extendible sectors (1c, 1d) being located one behind the other and ahead of the central fixed screed sectors, in the direction of the paving work progress, said extendible sectors (1c, 1d) being able to have a length similar to that of the whole central sector (1a + 1b), having a basic laying width 'L', said solution being suitable for obtaining a maximum laying width of at least 2.5 times the basic laying width 'L', characterised in that said screed further consists of: - a central fixed section of a certain basic length 'L', with a central hinge (Ac), parallel to the machine centre line, constituting two units (1a) and (1b) articulated to give a linear, convex, or concave profile of the mat cross section; said units (1a) and (1b) being fitted, at their external ends, with the support arms (4a, 4b) of the extendible sectors (1c,1d) respectively; said extendible sectors (1c,1d) being connected to the tow arms (A1, A2) respectively; - a first extendible sector (1d), with a length about equal to that of the whole central sector (1a + 1b) and located ahead of this in the direction of the paving work progress; - a second extendible sector (1c), with a length about equal to that of the whole central sector (1a + 1b) and located ahead of the first extendible sector (1d) in the direction of the paving work progress; - said extendible sectors (1c, 1d) being independently mobile in respect of the central sector (1a + 1b) in the direction of the laying width and in vertical direction.

Screed for a paver finisher

The road surfacing machine, such as for laying asphalt, has a pair of distributors (15,16) which can be shifted to increase the width of the main distributor by threefold. Carriers (27,28) can be moved across the width to position the distributors (15,16) at both sides of the main distributor (7), at the upper rear section. The distributors (15,16) are moved by a hydraulic cylinder system, for example, to give their setting over the road surface width to be covered from the rear positions at the main distributor (7).

Road surfacing machine has distributors at the main distributor which can be moved in and out to match the spreading surface width and increase the main distributor width by up to three times

PURPOSE:To make a maximum paving width twice or more the width of a main screed by a simple operation in a screed device of a paving machine. CONSTITUTION:At least two telescopic screeds 16, 16-which are extendible and retractable in left and right directions with respect to a main screed 12 and wherein the width of each of the screeds is made 1/2 or less times as large as the width of the main screed 12 are provided in each direction. The screeds 16, 16' are extended or retracted by operating a hydraulic cylinders 18, 18' at least in two stages so that a screed width thereof can be made twice or more as large as the width of the screed 12 in a maximumly extended state. Even if the maximum screed width is larger than twice as large as the width of the screed 12, the screeds 16, 16' in retracted state can be put within the width of the screed 12, and hence a large-sized railor is not needed in transportation so that transportation cost can be reduced.

Fujimoto Takafumi

Papers

Screed device for paving machine and the like