GB1325855A - Method and apparatus for insertion of joint material in plastic concrete - Google Patents

Abstract

1325855 Inserting expansion joint strips; screeding paving EDOCO TECHNICAL PRODUCTS Inc 28 June 1971 [30 June 1970] 30177/71 Heading E1G In apparatus for inserting a flat or cruciform filler strip 40, Figs. 2, 9, into a slab of unset paving to form a transverse expansion joint, the strip 40 is pulled through an inclined vibratory tube 80 which is traversed across the slab with its lower end in the paving and is followed by a vibratory floating screen pan 96, the tube 80 and pan 96 being mounted beneath a hydraulically-raised frame 54 suspended from a "cart" 42 running-e.g. on inverted channel rails 36 - on the underside of a frame 10, Fig. 1, extending across the paving slab, and the frame 10 having wheels 14 whereby it may be advanced to overlie successive joint locations. The floating pan 96, Fig. 2, carries an adjustable bracket 116 actuating a valve 122 controlling the lift cylinder 64 of the gravity-biassed frame 54 whereby the depth of insertion of the strip 40 is maintained constant. The frame 10, Fig. 1, carries a reel 38 of filler strip, displaceable side forms 126, 128 to support the paving edges during strip-insertion, a motor generator 20 and a double-run motor-driven chain (226, Figs. 3, 4 not shown) for traversing the cart at variable speed. In operation the frame 54, Fig. 2, is held raised clear of the paving while, the cart 42 is traversed across the slab (left to right in Fig. 1) to unreel a length of strip 40 and is then lowered to sink the lower end of tube 80 into the paving while the cart 42 returns in its strip-insertion traverse. During the unreeling traverse the wheels 14 are also driven and the side forms are opened so that the frame 10 advances to its next location. Two methods of pulling the strip 40 through the tube 80 are described. As shown a spring- loaded inclined rubber plunger 84, Fig. 2, presses against the strip through a side wall opening in the tube 80 to form a one-way device which grips the strip during the unreeling traverse, while the frame 10 is provided, adjacent the side form 128, with a clamping mechanism 136, Fig. 10, whereby the strip end is clamped by arms 170 which pass through side wall openings 94, Fig. 2, in the tube 80 to hold the strip stationary in the paving while the cart 42 returns towards the side form 126. At the end of its insertion traverse the tube 80 passes through a bristled opening in the side form 126 and the strip is automatically cut by a hydraulically actuated blade 242, Fig. 2. In an alternative strip-feeding mechanism, Figs. 23-26 (not shown), dispensing with the plunger 84 and the mechanism 136, the tube (80a) has an opening in its top wall into which project a pair of convergent strip-gripping feed wheels (336) driven from the traverse chain through an automatic clutch. Frame construction. The frame 10 is formed in two parts flange-connected at 26 to allow insertion pieces for different slab widths. Vertical corner trunnions 13 and adjustable diagonal braces 15 allow variation of the frame configuration. The wheels 14 are hydraulically driven and actuate a distance-indicator chain (Fig. 14, not shown). For transport, the wheel axles can be turned through 90‹ and the frame towed by a hydraulically-raised yoke 28. Intersection of transverse and longitudinal joints. Where the transverse joint strip 40 has to cross a longitudinal joint strip already laide.g. by the paving machine not shown-the longitudinal strip may simply be cut by a saw blade 83, Fig. 2, on the tube 80. Alternatively, Fig. 7 (not shown), the frame (54) may carry a pivoted strip-piercing element (224) which is hydraulically lowered into the paving as the cart 42 reaches a cam on the frame 10. Vibratory mechanism. The tube 80, Fig. 2, is carried by a plate 70 resiliently mounted on the frame 54 and provided with a vibrator 76. The screed pan 96 is floatingly suspended from frame 54 and has a vibrator 98. The two vibrators are automatically turned on and off during the traverses of the cart by switch probes. Strip-clamping mechanism. The clamping mechanism 136, Fig. 10, is mounted for limited displacement along tubes 152 on the rails 36, and includes abutments 134 whereby it is engaged by and moves with the cart 42 (not shown) during the last part of its unreeling traverse. The strip clamping arms 170 are linked to a vacuum device 144 controlled by the operator. Vertical displacement of the clamp on rods 156 as the strip is lowered into the paving is counterbalanced by a weight 180 and a pulley system. Return movement of the mechanism is prevented until the clamp device 144 is released by binding action and by an operator-controlled toothed locking device, Fig. 11 (not shown). Fig. 10 also shows a pivoted decelerating arm 318 engageable with the cart and linked to the speed control of the traverse motor, and that the cart is automatically slowed as it reaches the side form. Displaceable side forms. The side forms 126, 128, Fig. 1, are height-adjustable and are suspended from the frame 10 by weight-biassed cables and chains (Figs. 12, 13 not shown) so that they can be swung outwardly by hydraulic cylinders (280). To avoid damage to the paving edge a wiping action is introduced by opening the side forms just after the forward movement of frame 10 has commenced.