Tunnel formwork

Claim 2

A tunnel formwork comprising a horizontal formwork portion and two vertical formwork portions, which portions are resistant to bending, the vertical portions being movable with respect to the horizontal portion, each vertical formwork portion being connected to the horizontal portion by guides, there being at least two guides arranged in the area of the junction points between adjacent formwork portions and at least two guides connecting the lower region of the vertical formwork portions with the central area of the horizontal portion, means being provided which permit the formwork portions to be secured in at least one position.

Claim 3

A tunnel formwork as claimed in claim 1 wherein the guides provided at the junction points of the formwork portions are pairs of double guides similar to bell crank levers, which are each arranged to be pivotable by means of an actuating lever pivotally mounted on the horizontal formwork portion, the lower ends of the vertical formwork portions being provided with jacks.

Claim 4

A tunnel formwork as claimed in claim 2 wherein the horizontal formwork portion comprises at least three telescopically interconnected supporting beams the pivot bearings of the actuating lever and of the lower guide being provided on the outer supporting beams of said horizontal formwork portion.

Claim 5

A tunnel formwork as claimed in any of claim 1 including a formwork transporting vehicle serving to move the complete formwork, said vehicle having three variable length supports, the arrangement of which in cross-sectional shape corresponds to an isosceles triangle, the base of which is at right angles to the direction of movement of the vehicle.

Claim 6

A tunnel formwork as claimed in claim 4 wherein the supports are pivotally connected with the transporting vehicle by means of joints and are arranged to be held in their pivotal planE by variable length or adjustable diagonal struts.

Claim 7

A tunnel formwork arrangement for use in forming tunnels, especially concrete lined tunnels; said arrangement comprising a horizontal bend resistant formwork portion having an upwardly facing forming surface, two vertical bend-resistant formwork portions having respective outwardly facing forming surfaces, said vertical portions being arranged to extend substantially perpendicularly downwardly from opposite ends of the horizontal portion, two similar first guide means for connecting respective upper ends of said vertical portions to respective opposite ends of said horizontal portion, and two similar second guide means extending from respective lower ends of said vertical portions to respective central portions on said horizontal portion for assisting in bracing the horizontal portion and the vertical portions in position with respect to one another, the first and second guide means including means for selectively maintaining the framework portions in at least one position with respect to one another such that a self supporting formwork having three forming surfaces is obtained.

Claim 8

A tunnel formwork arrangement for use in forming tunnels, especially concrete lined tunnels; said arrangement comprising a horizontal bend resistant formwork portion having an upwardly facing forming surface, two vertical bend-resistant formwork portions having respective outwardly facing forming surfaces, said vertical portions being arranged to extend substantially perpendicularly downwardly from opposite ends of the horizontal portion, two similar first guide means for connecting respective upper ends of said vertical portions to respective opposite ends of said horizontal portion, and two similar second guide means extending from respective lower ends of said vertical portions to respective central portions on said horizontal portion for assisting in bracing the horizontal portion and the vertical portions in position with respect to one another, the first and second guide means including means for selectively maintaining the framework portions in at least one position with respect to one another such that a self supporting formwork having three forming surfaces is obtained.

Claim 9

A tunnel formwork as claimed in claim 6, wherein the first guide means includes manually operable lever means operable to selectively lock and unlock the horizontal and vertical portions in a fixed self-supporting position with respect to one another, said lever means including a lever coupling member for coupling levers arranged at both ends of the horizontal portion together such that both vertical portions are releasable simultaneously.

Claim 10

A tunnel formwork as claimed in claim 6, wherein the first guide means includes three pivotal guide bars connected to one another, a first of said three bars being pivotal at one end thereof about a first pivot pin fixed to the vertical portion and being pivotal at the other end thereof about a second pivot pin fixed to the horizontal portion, a second of said three bars being pivotal at one end thereof about said first pivot pin and being pivotal at the other end thereof about a third pivot pin fixed to a third of said three bars, the third of said three bars being pivotal at one end thereof about said third pivot pin and being pivotal at the other end thereof about a fourth pivot pin fixed to the horizontal portion, said third bar being rigidly attached to a manually operable lever such that the third bar can be pivoted about the fourth pivot pin by manual forces to consequently move the ends of said vertical and horizontal portions over a predetermined path with respect to one another during form locking and unlocking operations.

Claim 11

A tunnel formwork as claimed in claim 8, wherein the axis of the third pivot pin is positioned vertically above a line between the axes of the first and fourth pivot pins when the first guide means is in a form locking position, whereby a so-called dead center must be passed to release the forms from the form locking position.

Claim 12

A tunnel formwork as claimed in claim 6, wherein sealing means are provided for sealing the junction between respective vertical and horizontal portions.

Claim 13

A tunnel formwork as claimed in claim 10, wherein said sealing means includes plastic strips fitted to the vertical and horizontal portions by beading, said strips having grooves for permitting deformation upon removal of the forms and the consequent change in position of the respective horizontal and vertical portions with one another.

Claim 14

A tunnel formwork as claimed in claim 6, wherein the second guide means include struts attached at one end adjacent the bottom ends of the vertical portions and attached at the other end to attachment points on the horizontal portion, the attachment points being spaced close to the respective ends of the horizontal portion in order to leave sufficient room under the horizontal portion and between the struts for assembly, disassembly and transportation of the formwork.

Claim 15

A tunnel formwork as claimed in claim 11, wherein the first guide means includes tHree pivotal guide bars connected to one another, a first of said three bars being pivotal at one end thereof about a first pivot pin fixed to the vertical portion and being pivotal at the other end thereof about a second pivot pin fixed to the horizontal portion, a second of said three bars being pivotal at one end thereof about said first pivot pin and being pivotal at the other end thereof about a third pivot pin fixed to a third of said three bars, the third of said three bars being pivotal at one end thereof about said third pivot pin and being pivotal at the other end thereof about a fourth pivot pin fixed to the horizontal portion, said third bar being rigidly attached to a manually operable lever such that the third bar can be pivoted about the fourth pivot pin by manual forces to consequently move the ends of said vertical and horizontal portions over a predetermined path with respect to one another during form locking and unlocking operations.

Claim 16

A tunnel formwork as claimed in claim 6, wherein said first guide means includes means to lock the ends of said vertical and horizontal portions together to form a right-angle corner form by the intersection of their respective upper and outward surfaces.