A METHOD OF CLEANING MOULDS IN A LONG MOULD BED FOR CASTING CONSECUTIVE CONCRETE ELEMENTS AND A RAIL-BOUND MOULD-CLEANING CARRIAGE

Abstract: When casting consecutive concrete elements such as concrete sleepers there is used an elongate mould bed comprising a plurality of mutually adjacent vertically movable moulds. Mould stripping, removal of cast concrete elements, cleaning of the mould and the preparation for a further casting operation are effected with the aid of carriages arranged for movement along the mould bed on rails. The mould is cleaned with the use of a separate carriage having a plurality of vertically movable scraper plates (78) arranged to engage the sides of the mould and a plurality of blow nozzles (67) arranged to deliver a jet of air at high pressure.

Description: A method of cleaning moulds in a long mould bed for casting consecutive concrete elements and a rail-bound mould-cleaning carriage 5 Technical Field The present invention relates to a method of cleaning moulds for casting consecutive concrete elements, such as concrete sleepers, a long bed comprising a plurality of mutually adjacent, vertically movable such moulds or 10 forms. Backσround art A method of manuf cturing a plurality of sequential pre-tensioned concrete elements, for example concrete 15 sleepers, in a long mould bed is described in Swedish Patent Specification No. 77 05021-9. US Patent 3 732 044 describes a production line for products of prestressed concrete comprising certain installations for cleaning and oiling. 20 Objects of invention To enable concrete elements to be manufactured in accordance with factory standards, it is particularly important that the various moulds in the mould bed can 25 be thoroughly cleaned of concrete residues after the mould-stripping operation. The cleaning operation obtains, moreover, particular significance in those instances, when the mould shall be prepared in a manner to enable separate insert elements, such as rubber 30 plates, to be cast in the concrete elements. As will be understood, any concrete particles which remain in the mould may cause the insert elements to be positioned obliquely when placed in the mould, which has disastrous consequences in respect of the quality of the cast 35 concrete element. Experiments have shov/n that it is not sufficient to vacuum clean the mould, because of the strength with which residual concrete particles adhere to the sides of the mould. Thus, in order to remove concrete residues the mould sides must be subjected to some kind of mechanical working, although experiments have shov/n that this does not. provide fully satisfactory result either. It has surprisingly been found, however, that mechanical working of the mould sides by means of suitable scraping devices, * e.g. scraper plates, while blowing air under high pressure into the mould through nozzles let into the mould provides a very good result. Brief summary of invention In the method according to the invention the moulds are cleaned from concrete residues by .the combined action of blowing and scraping with the use of vertically movable scraper devices arranged to contact the inner surfaces of the mould, and with the use of blower nozzles inserted in the mould. The blower nozzles, "which are suitably in the form of fan valves, produce a linear jet of air which cuts like a knife agai st concrete particles adhering to the mould. The scraper devices are, in turn, used primarily to remove concrete particles in the region v/ ' nere the insert elements are later to be mounted, since it is -of- particular- importance that said insert elements are placed correctly in the mould. Because the scraper devices move up and down in the mould, an effective mechanical cleaning operation is effected, while subjecting the adhering concrete particles to strong jets of air at the same time. The removed concrete residues collect in the bottom of the mould, from which they can be readily removed with the aid of a vacuum-cleaner suitably arranged on a : rail-bound carriage following said mould-cleaning carriage. A preferred embodiment of a cleaning carriage provided with scraper devices and blow nozzles, for use when ' pplying the invention will now be described in more detail with reference to the accompanying schematic drawings. 10 Brief description of the Drawings Figure 1 is a plan viev of the cleaning carriage. Figure 2 is a front viev/ of the carriage illustrated in 15 Figure 1. Figure -3 ' -is- a -side viev/ of the carriage illustrated in ' Figures 1 and " 2. 20 Figure 4 illustrates on the left side thereof part of the side viev/ of the carriage according to Figure 3 in " larger scale, while to the right of Figure 4 is illustrated a corresponding' -part of the carriage in front viev/ and in the same scale as the left part of 25 the figure. ■ " •. *' * - Description ' of the preferred embodiment When casting consecutive co-ricrete ' -elements such as concrete sleepers ' in- a long mould bed comprising a 30 plurality of mutually adjacent, vertically movable moulds with the use of carriages arranged for movement along the bed on rails, subsequent to casting and hardening the concrete elements the moulds are successively stripped. For that purpose special devices 35 (not shov/n) may be used located on a carriage and arranged to withdraw the mould holders of respective moulds and to release the cast concrete elements by pressing the mould dov/n against vertically movable mould holder elements swung in beneath the mould. The cast concrete elements may then be removed by using special carriages for this purpose. The work of preparing the mould for renewed casting shall then begin. The prime work in connection here¬ with is the cleaning of the mould, whereat there is used a separate cleaning carriage which will be described hereinafter.The mould shall also be oiled, which is suitably cone after placing in the mould separate elements, such as rubber plates (not shov/n) , which are to be cast in the concrete elements . The illustrated cleaning carriage comprises a robust frame structure 61 having four wheels 62 arranged to run on rails 30 and driven by a reversible air motor 63 via a chain. The carriage has four pneumatic cylinders 64 and two pneumatic cylinders 65 for moving holders 66 up and dov/n. The holders 66 carry a plurality of fan¬ like blow nozzles 67 arranged to produce linear air flows under high pressure against the sides of the mould. The nozzles co-act with sixteen scraper plates 78, arranged to engage the sides of the mould and therewith to cleanse said sides of concrete residues. The scraper plates 78 are arranged to move up and dov/n under the action of cylinders 65A and 65B which carry out a slow, oscillating movement. Also arranged on the carriage is an air compressor 68 and four magnet valves 69. The cleaning carriage is also arranged to move along the mould bed at tv/o speeds. Thus, the motor 63 drives the carriage at a maximum speed until the motor receives a signal for creep driving. The carriage then moves slowly forwards until it reaches its correct position, whereat the motor stops and the cylinder 64 locks the carriage in this position. The cylinder 65A then begins to move under the action of a limit switch (not shov / n) , whereat the magnet valve 69A opens. The cylinder 65A then returns until a further limit switch (not shov / n) is activated, " whereat the direction of movement of the cylinder is reversed, etcetera. At the same time a time relay (not shov / n) is activated, which causes cyclic closing and opening of the valves 69A and 693, whereat air under high pressure is delivered from the nozzles 67 at suitable intervals. When the cylinder 64 has moved to its starting position, the motor 63 is started and a nev/ cycle commences. The carriage is also provided with an anti-collision device having a safety switch 79. Separate protective plates 18 prevent concrete residues from splashing- against the nozzles, for example, during a * cleaning operation.

Claims: Claims 1. A method of cleaning a mould for casting consecutive concrete elements, characterized by cleaning the mould of concrete residues by combined blowing and scraping operations v/ith the use of vertically movable scraper devices engaging the inner surfaces of the mould and blow nozzles arranged in the mould for delivering a jet of air at high pressure. 2. A method according to claim 1, characterized by using a rail-bound movable carriage for carrying the scraper devices and the blow nozzles and moving said carriage along the mould bed. 3. A method according to claim 2, characterized by locking the carriage on the rails before aczivating the scraper devices and the blow nozzles. 4. A rail-bound cleaning carriage for use when manufacturing con-secutive concrete elements, in an elongate bed of sequential moulds, said carriage including a frame structure (61) provided v/ith rail- bound v/heels (62) and a drive motor (63) , characterized by means (61) for releasably fixing the carriage in an exact location, relative to the mould (16) , vertically movable scraper means (78) arranged to engage the inner surfaces of the mould to clean said surfaces of concrete residues, vertically movable blow nozzles (67) arranged for lowering into, the mould, and a compressor (63) and a plurality of magnet valves (69) connected to blow nozzles (67) for delivering an air stream under high pressure therefrom. c_.'-τ

Inventors: SOEDERBERG S, STEEN I
Applicants: A BETONG AB, SABEMA MATERIAL AB, SOEDERBERG S, STEEN I
Application year: 1981
Main classification: B28B5
IPC codes: B28B1, B28B5, B28B7, B28B13, B28B17