Concrete-molding apparatus having an inner mold member with variable dimension periphery

Claim 2

In a mold for concrete pipe and the like having spaced inner and outer cylindrical mold members, the improvement which comprises a linear seam disposed throughout the length of a peripheral surface of the inner mold, and mechanism interiorly of the mold including a member adjacent the lengthwise extent of said seam having tapered sides for wedging insertion into the seam, at least one support means for said member with tapered sides, said support means including at least one pair of upright arms secured on said inner mold member and having a hinged, scissorlike mounting, spring members carried by the arms and maintained under compression when the member is inserted in the seam and expanding when said member is withdrawn from the seam; and drive means attached to the support means and arranged to force the member with tapered sides into the seams in a spreading and sealing action in one camming movement of the arms and springs for closing the seam during molding, and causing a withdrawal of said member from the seam in another camming movement of the arms and springs thereby reducing the dimension of said peripheral surface as the seam is closed to provide clearance with a formed shape in the mold.

Claim 3

An inner mold as defined in claim 1, wherein said mechanism includes a plurality of said support means supporting the insert member at intervals along its length and drive means mounted on each of said support means and connected to the insert member, said drive means being arranged for synchronized operation in said wedging and withdrawal actions.

Claim 4

An inner mold as defined in claim 1, having gasket material on the tapered sides of said insert member.

Claim 5

An inner mold as defined in claim 1, wherein said drive means is reversible whereby to be operable to force said insert member into the seam in one movement and withdraw it from the seam in a reverse movement.

Claim 6

An inner mold as defined in claim 1, wHerein the edges of the inner mold abutting the seam taper outwardly and downwardly from contact surfaces at the outer periphery of the mold.

Claim 7

An inner mold as defined in claim 1, wherein said support means comprises two pairs of spaced upright arms with associated spring assemblies which are actuated by said drive means.

Claim 8

In a mold as defined in claim 1, cam means carried by said drive means in contact with coacting surfaces of said arms, vertical coacting surfaces thereof spreading the seam-defining surfaces of the mold when engaged by the cam means, and oblique coacting surfaces thereof permitting the seam-defining surfaces to contact when engaged by the cam means.

Claim 9

An inner mold form for casting concrete pipe and the like, comprising: a substantially cylindrical member, said cylindrical member being opened longitudinally along its periphery whereby a slotlike opening is defined in said cylindrical member along its longitudinal dimension, said cylindrical member being made of a resilient material whereby the width of said slotlike opening and the diameter of said cylindrical member may be selectively varied by expanding or contracting said cylindrical member; a longitudinal insert member positioned adjacent said slotlike opening, said insert member having tapered sides for wedging insertion into said slotlike opening; cam follower means formed on said insert member; first and second rigid arm means mounted on the interior of said cylindrical member on opposite sides, respectively, of said slotlike opening and adjacent said cam follower means, said rigid arm means being pivotally connected to each other to form a scissorlike structure which straddles said insert member and said slotlike opening, said rigid arm means defining cam surfaces on their facing edges for said cam follower means, said cam surfaces being shaped so that as said insert member is wedged into said slotlike opening the camming action of said cam follower means on the cam surfaces forces the scissorlike structure formed by said rigid arm means apart thereby to expand said cylindrical member and as said insert member is withdrawn from said slotlike opening the scissorlike structure formed by said rigid arm means closes thereby to contract said cylindrical member; and drive means connected to said insert member, said drive means being selectively operable to wedge said insert member into said slotlike opening and withdraw it therefrom.

Claim 10

An inner mold form for casting concrete pipe and the like, comprising: a substantially cylindrical member, said cylindrical member being opened longitudinally along its periphery whereby a slotlike opening is defined in said cylindrical member along its longitudinal dimension, said cylindrical member being made of a resilient material whereby the width of said slotlike opening and the diameter of said cylindrical member may be selectively varied by expanding or contracting said cylindrical member; a longitudinal insert member positioned adjacent said slotlike opening, said insert member having tapered sides for wedging insertion into said slotlike opening; cam follower means formed on said insert member; first and second rigid arm means mounted on the interior of said cylindrical member on opposite sides, respectively, of said slotlike opening and adjacent said cam follower means, said rigid arm means being pivotally connected to each other to form a scissorlike structure which straddles said insert member and said slotlike opening, said rigid arm means defining cam surfaces on their facing edges for said cam follower means, said cam surfaces being shaped so that as said insert member is wedged into said slotlike opening the camming action of said cam follower means on the cam surfaces forces the scissorlike structure formed by said rigid arm means apart thereby to expand said cylindrical member and as said insert member is withdrawn from said slotlike opening the scissorlike structure formed by said rigid arm means closes thereby to contract said cylindrical member; and drive means connected to said insert member, said drive means being selectively operable to wedge said insert member into said slotlike opening and withdraw it therefrom.

Claim 11

The invention recited in claim 8, including biasing means for biasing the cam surfaces of said rigid arm means in contact with said cam follower means formed on said insert member.

Claim 12

The invention recited in claim 9, wherein said biasing means comprises a spring-biased rod mechanism.

Claim 13

The invention recited in claim 8, wherein: a first portion of the cam surfaces defined by said rigid arm means are substantially parallel with respect to each other whereby as said cam follower means are moved along said first portion said rigid arms are held wedged apart; a second portion of the cam surfaces defined by said rigid arm means are diverging with respect to each other whereby as said cam follower means are moved along said second portion towards said slotlike opening said rigid arm means are forced apart and as said cam follower means are moved along said second portion away from said slotlike opening said rigid arm means close towards each other; and said first and second portions of the cam surfaces are adjacent each other, said first portion being adjacent said slotlike opening, said second portion being remote from said slotlike opening.

Claim 14

An inner mold form for casting concrete pipe and the like, comprising: a substantially cylindrical member, said cylindrical member being opened longitudinally along its periphery whereby a slotlike opening is defined in said cylindrical member along its longitudinal dimension; a longitudinal insert member positioned adjacent said slotlike opening, said inserT member having tapered sides for wedging insertion into said slotlike opening; first and second rigid arm means mounted on the interior of said cylindrical member on opposite sides, respectively, of said slotlike opening, said rigid arm means being pivotally connected to each other to form a scissorlike structure which straddles said insert member and said slotlike opening; biasing means connected between said rigid arm means, said biasing means being operable to bias said first and second rigid arm means towards each other whereby to bias said cylindrical member in a contracted position; and selectively operable means for wedging said insert member into said slotlike opening and withdrawing it therefrom.

Claim 15

An inner mold form for casting concrete pipe and the like, comprising: a substantially cylindrical member, said cylindrical member being opened longitudinally along its periphery whereby a slotlike opening is defined in said cylindrical member along its longitudinal dimension; a longitudinal insert member positioned adjacent said slotlike opening, said inserT member having tapered sides for wedging insertion into said slotlike opening; first and second rigid arm means mounted on the interior of said cylindrical member on opposite sides, respectively, of said slotlike opening, said rigid arm means being pivotally connected to each other to form a scissorlike structure which straddles said insert member and said slotlike opening; biasing means connected between said rigid arm means, said biasing means being operable to bias said first and second rigid arm means towards each other whereby to bias said cylindrical member in a contracted position; and selectively operable means for wedging said insert member into said slotlike opening and withdrawing it therefrom.