System for control of the condition of mixed concrete
First Claim
Patent Images
1. A mobile concrete mixer for operation by a driver-operator comprising:
- (1) a vehicle provided with a vehicle engine and engine throttle;
(2) a spirally-finned, rotatable mixing drum having a discharge end mounted on such vehicle;
(3) a drum motor means operatively coupled to the drum to rotate the drum in either the mixing or discharge directions;
(4) drum rotation detection means positioned to generate a signal corresponding to the rotation of the drum and the direction of rotation of the drum;
(5) a driver-operated drum control switch to cause the drum motor means to rotate the drum in the mixing or discharged directions, or stop the drum rotation, characterized by a programmed controller for automatically advancing the rotation of the drum in the mixing direction through the stages of a predetermined drum rotation regime that includes at least a higher speed stage for effecting mixing and a lower speed stage for effecting agitation while permitting interruption of such process by an operator, wherein said controller, beyond a limited period of time or amount of rotation in the mixing direction, always controls the rotational speed of the drum in the mixing direction.
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Abstract
A mobile cement mixer is provided with a programmed controller that automatically causes the mixing of concrete to follow a predefined mixing regime that is interruptable by an operator but will resume the mixing regime at the appropriate stage.
129 Citations
51 Claims
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1. A mobile concrete mixer for operation by a driver-operator comprising:
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(1) a vehicle provided with a vehicle engine and engine throttle; (2) a spirally-finned, rotatable mixing drum having a discharge end mounted on such vehicle; (3) a drum motor means operatively coupled to the drum to rotate the drum in either the mixing or discharge directions; (4) drum rotation detection means positioned to generate a signal corresponding to the rotation of the drum and the direction of rotation of the drum; (5) a driver-operated drum control switch to cause the drum motor means to rotate the drum in the mixing or discharged directions, or stop the drum rotation, characterized by a programmed controller for automatically advancing the rotation of the drum in the mixing direction through the stages of a predetermined drum rotation regime that includes at least a higher speed stage for effecting mixing and a lower speed stage for effecting agitation while permitting interruption of such process by an operator, wherein said controller, beyond a limited period of time or amount of rotation in the mixing direction, always controls the rotational speed of the drum in the mixing direction. - View Dependent Claims (2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50)
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7. In a concrete mixer comprising:
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(1) a vehicle provided with a vehicle engine; (2) a spirally-finned, rotatable mixing drum having a discharge end mounted on such vehicle; (3) a drum motor means operatively coupled to the drum to rotate the drum in either the mixing or discharge directions; (4) drum rotation detection means positioned to generate a signal corresponding to the rotation of the drum and the direction of rotation of the drum; (5) a driver-operated drum control switch to cause the drum motor means to rotate the drum in the mixing or discharged directions, or to stop the drum rotation, (6) a programmed controller for automatically advancing the rotation of the drum through the stages of a predetermined drum rotation regime that includes at least one mixing stage and an agitation stage while permitting interruption of such process by an operator, wherein said controller is programmed to provide that, once mixing has commenced and until mixing has been completed, the driver can operate the drum to turn in the discharge direction, but only for a predetermined limited amount short of the commencement of discharge.
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51. A method of mixing concrete to maximize the entrainment of air characterized by:
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(1) mixing the concrete initially at a first, elevated mixing speed, in the range of 11-12 rpm, which causes a substantial quantity of air to become entrained in such concrete; and (2) continuing the mixing of the concrete to a conclusion at a second, reduced mixing speed, in the range of 6-8 rpm, which minimizes the extent to which previously entrained air is released from the concrete.
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Specification