Riser assembly

Abstract

A riser assembly for construction of riser apertures in concrete floors comprises a frame member with a channel forming a shutter. A joist spanning the riser aperture is connected to the channel with a fixing which can slide axially within the channel when connected to the joist. A method of constructing the riser aperture is also disclosed, permitting the adjustment of the position of the joist by sliding the joist axially along the channel after the riser aperture is formed. Upper and lower walls of the channel converge to form a dovetail, which anchors the channel along its length within the settable material forming the floor around the riser, and also helps to retain the fixing within the channel.

1 . A riser assembly for the construction of a riser aperture in a cast floor, the riser assembly comprising:
 a frame member adapted to exclude settable material from the riser aperture, the frame member comprising a channel having an axis and a channel opening, the channel comprising an outer wall connected to upper and lower channel walls wherein the upper and lower channel walls extend between the outer wall and the channel opening;   a joist adapted to span at least a part of the riser aperture; and   a fixing adapted to connect the joist to the channel, wherein the fixing is adapted to slide axially within the channel when connected to the joist.   
     
     
         2 . A riser assembly as claimed in  claim 1 , wherein first outer ends of the upper and lower channel walls are connected to the outer wall, and second inner ends of the upper and lower walls are spaced from the outer wall and the first ends, and wherein the spacing between the first ends of the upper and lower channel walls is greater than the spacing between the second ends of the upper and lower walls. 
     
     
         3 . A riser assembly as claimed in  claim 1 , wherein the upper and lower walls at least partially converge as they extend from the outer wall forming non-parallel convergent sections of the upper and lower channel walls. 
     
     
         4 . A riser assembly as claimed in  claim 1 , wherein the cross-section of the upper and lower walls and the outer wall has the form of a dovetail along the length of the channel. 
     
     
         5 . A riser assembly as claimed in  claim 1 , wherein the frame member includes upper and lower shutters connected to the channel, wherein the upper and lower shutters are in a common plane with the channel opening. 
     
     
         6 . A riser assembly as claimed in  claim 1 , wherein the channel has lips extending between the upper and lower channel walls and the channel opening, and wherein the lips are in a common plane with the channel opening. 
     
     
         7 . A riser assembly as claimed in  claim 1 , wherein the fixing is selectively lockable in the channel. 
     
     
         8 . A riser assembly as claimed in  claim 7  wherein the fixing can be inserted into the channel in a first configuration, and while in the channel can then shift to a second configuration in which the fixing is locked in the channel. 
     
     
         9 . A riser assembly as claimed in  claim 8 , wherein the fixing comprises an asymmetric locking member which can be rotated between the first and second configurations. 
     
     
         10 . A riser assembly as claimed in  claim 7 , wherein the fixing comprises at least one outer wall arranged at the same angle as an inner surface of at least one of the upper and lower channel walls, such that the at least one outer wall of the fixing engages the inner surface of the at least one of the upper and lower channel walls when the fixing is locked in the channel in the second configuration. 
     
     
         11 . A riser assembly as claimed in  claim 1 , wherein convergent sections of the upper and lower channel walls are straight. 
     
     
         12 . A riser assembly as claimed in  claim 1 , wherein the upper and lower channel walls make an acute angle with the outer wall of the channel. 
     
     
         13 . A riser assembly as claimed in  claim 1 , wherein the angle between the outer wall and the upper channel wall is the same as the angle between the outer wall and the lower channel wall. 
     
     
         14 . A riser assembly as claimed in  claim 1 , wherein the joist spans between parallel sides of the riser aperture, and wherein at least one end of the joist is connected to the channel in at least one frame member by the fixing so that it is slidable relative to the channel at least at one end of the joist. 
     
     
         15 . A riser assembly as claimed in  claim 1 , having at least first and second joists, wherein one end of the first joist is connected to the frame member and the other end of the first joist is connected to the second joist. 
     
     
         16 . A riser assembly as claimed in  claim 1 , wherein the joist is formed from a composite material comprising a fibre and a settable material. 
     
     
         17 . A riser assembly as claimed in  claim 1 , wherein at least one frame member is incorporated in a slip-formed wall which forms a part of the boundary of the riser aperture. 
     
     
         18 . A riser assembly as claimed in  claim 17 , including a bracket supporting a service conduit passing through the riser aperture wherein the bracket connects into the channel of the frame member supported on the slip-formed wall. 
     
     
         19 . A method of constructing a riser aperture in a floor, the method comprising surrounding at least a part of the riser aperture with a frame member adapted to exclude settable material from the riser aperture, the frame member comprising a channel having an axis and a channel opening, the channel comprising an outer wall connected to upper and lower channel walls, wherein the upper and lower channel walls extend between the outer wall and the channel opening;
 connecting a joist across the riser aperture by connecting the joist into the channel opening by at least one fixing, wherein the fixing is slidable within the channel when connected to the joist; and   adjusting the position of the joist by sliding the joist axially along the channel.   
     
     
         20 . A method as claimed in  claim 19 , wherein after the step of adjusting the position of the joist by sliding the joist axially along the channel, the position of the fixing in the channel is locked by tightening the fixing when the joist is in the desired location relative to the axis of the channel. 
     
     
         21 . A method as claimed in  claim 19 , wherein the channel opening is accessible from the riser aperture, and wherein the outer wall of the channel is cast in the settable material forming the floor surrounding the riser aperture. 
     
     
         22 . A method as claimed in  claim 19 , wherein at least one frame member is formed in a slip-formed wall, which forms a part of the boundary of the riser aperture. 
     
     
         23 . A method as claimed in  claim 19 , wherein the at least one frame member is fixed in position on the slip-formed wall by ties connecting it to metal reinforcing elements prior to slip forming the slip-formed wall. 
     
     
         24 . A method as claimed in  claim 19 , wherein the riser assembly comprises upper and lower shutters connected to the channel, wherein the upper and lower shutters incorporate upper and lower horizontal walls each having an array of perforations, and wherein the method includes admitting concrete into the spaces between the channel and the upper and lower shutters. 
     
     
         25 . A method as claimed in  claim 19 , including supporting a service conduit passing through the riser aperture with a bracket which connects into the channel and is slidable therein. 
     
     
         26 . A method as claimed in  claim 19 , including constructing a wall above the joist, wherein the joist and the wall are at least partially in the same vertical plane and wherein the joist supports the wall. 
     
     
         27 . A method as claimed in  claim 19 , including connecting the joist to the channel with more than one bracket at one end of the joist. 
     
     
         28 . A method as claimed in  claim 19 , including connecting at least one frame member across the riser aperture by a fixing permitting sliding of the frame member relative to the channel when the two are connected. 
     
     
         29 . A method as claimed in  claim 28 , including connecting first and second frame members across the riser aperture by a respective fixing on each frame member permitting sliding of the frame member relative to the channel when the two are connected;
 adjusting the relative positions of the first and second frame members by sliding one of the first and second frame members axially along the channel to form a space between the first and second frame members; and   casting a settable material into the space between the first and second frame members.