GB2101011A - Combined sieving and mixing device - Google Patents

Abstract

A combined sieving and mixing device is provided comprising a drum (2) on a frame (7), the drum being rotatable around a first axis (5) and tiltable around a second axis (6) and having an opening (16) through which said first axis extends. In the bottom of said drum opposite said opening a removable section is provided, in the place of which sieving means (18) can be placed. The sieving means (18) can consist of a frusto-conical sieve (20) extending into said drum (2) with an insert (19, 23) which facilitates the outflow of sieved material from said drum. An additional sieve (24) may be provided in the opening (16). <IMAGE>

Description

SPECIFICATION Combined sieving and mixing device The invention relates two a combined sieving and mixing device comprising an on a frame around a first axis rotatable and around a second axis turnable drum having an opening through which said first axis extends.

In building it is previously known to use a concrete mixer of the type which is activated manually or by means of a smaller power drive. In concrete casting sieved sand is usually ordered from a gravel-pit to be mixed out with cement and water in a concrete mixer. However, to obtain a smooth surface after casting it is common to afterwards by hand sieve the sand to get rid of greater particles therein. Such a manual sieving operation is also performed with completely unsieved sand when e.g. a gravel-pit is available. This sieving work is often heavy and time consuming and often two persons are required to carry out the same.

The object of the invention is to provide a combined sieving and mixing device which by withdrawing the above mentioned disadvantages in a simple and reliable way can be used as a sieve as well as a concrete mixer.

The object is achieved according to the invention by a combined sieving and mixing device which is characterized in that said drum in its bottom opposite said opening is provided with a removable section, in the place of which sieving means can be placed.

Forthe restthere are many other opportunities than at casting where a quantity of sand is to be sieved. The device according to the invention can also be used to sieve out sand, so that gravel or shingle is obtained to e.g. pathways.

Such a combined sieving and mixing device does so find other applications than at concrete casting, for what reason a concrete mixing device with an equipment for sieving must be much more usable.

The invention will be described more in detaii with reference to the accompanying drawings which show preferred embodiments of the invention.

Fig. lisa sectional view through a combined sieving and mixing device according to the invention.

Fig. 2 is a rear view of the device according to Fig.

1.

Fig. 3 is a perspective view of a first embodiment of an insert of a sieving means ofthe device according to Figs. 1 and 2.

Fig. 4 is a side sectional view of a second embodiment of said insert.

Fig. 5 is a perspective view of a third embodiment of said insert.

Fig. 6 is a partial end view of a first embodiment of the sieve of said sieving means.

Fig. 7 is a partial end view of a second embodiment of said sieve.

With reference ta Figs. 1 and 2 a combined sieving and mixing device is shown, under which a wheelbarrow 1 is placed. The device comprises a drum 2, which by means of a motor 3 and a gear ring 4 is rotatable around its centre axis 5. Further, the drum is tiltable around a centre axis 6 for emptying concrete when the device is used as a concrete mixer and to empty material which is sieved out when the device is used as a sieve. The drum is journalled on a frame 7, upon which said motor 3 is fastened and a handle 8 for the emptying operation can be located in different angle positions of said drum. A stirrer 9 for the concrete is provided along the inner wall of said drum. On the drawing only one stirrer is shown, but of course several stirrers can be provided in the circumferential direction along the inner wall of said drum.A U-shaped mounting 10 is secured to said handle 8 and journalled at 11 and 12, and supports a bearing 13 for said drum.

Four equally spaced reinforcement wings 14 are welded on said drum at their outer ends. The inner ends of said reinforcement wings are met in a point, and in this point said bearing tap 15 is connected to said wings and placed in a bearing 13, so that said drum can be rotated around the centre axis 5 by means of said motor 3.

The drum has an opening 16 for filling and emptying. In the end bottom of said drum opposite said opening 16 a circular hole 17 is provided, in which, when said drum is used as a concrete mixer, a cover (not shown) is fastened by means of e.g. screws and nuts. Said opening 16 and said hole 17 are so placed on said drum that said centre axis 6 extends therethrough.

According to the invention said cover can be replaced by a sieving means 18 which is secured at said drum by means of said screws and nuts. This sieving means consists preferably of a frame 19 to which a frustoconical sieve 20 is fixed, the little base 21 of which is closed and the big base 22 of which is open and covers said hole 17 in said drum 2. Said sieving means comprises also an insert which consists of four coaxially with said sieve after each other provided massive tube sections 22, and having one end fixed on the frame 19 carrying said sieve, said tube sections having toward each other faced ends disposed substantially in the same plane.

As can be seen in Fig. 1 an additional sieve 24 formed as a basket with a bended edge 25 can be placed in the opening 16 to get a rough sieving of the sand. Such an additional sieve 24 can preferably be used as an extra equipment to a previously known concrete mixer. On the inner wall of said additional sieve 24 preferably shovel-shaped means 26 are provided to obtain a better sieve effect. As an alternative to the provision of said shovel-shaped means 26 the section area of said basket can be noncircular, and have inwardly projection edges. At least one handle 27 is provided on said drum at said opening 16, said handle being used to tilt said drum around said centre axis 6 when emptying the same.

In Fig. 3 the insert consisting of tube sections 23 and frame 19 is shown. As can be seen, a mounting ring 28 with holes 29 is secured to said frame.

With reference to Figs. 4-7 modified embodiments of parts of the sieving means are to be described. In.

Fig. 4 an insert is shown said tube sections 23 of which are frustoconcially formed and partly introduced into each other. Fig. 5 shows an insert in which the tube sections 23 are frustoconically formed and taper the end opposite the mounting ring 28. Said tube sections can also be polygonal and are in this embodiment shown as hexagonal. Fig. 6 shows a modified embodiment of the sieve 20 wherein massive flanges 30 are provided along the periphery thereof, said flanges extending in the longitudinal direction of said sieve. In Fig. 7 the sieve 20 is provided with a corrugated surface. The embodi ments according to Figs. 6 and 7 are provided for the reason that the sand not shall flow off said sieve. The sand is to be hold as long time as possible on the sieve.

The hole in the bottom of the drum is in a preferred embodiment of the invention in the order of 25 centimeters and a reinforcement ring 31 is preferably provided along the periphery of said hole, said cover and said mounting ring 29 being connectable to said reinforcement ring 31. The reinforcement ring is fixed to said drum, e.g. by welding. The reinforcement wings 14 are provided for the positioning of the bearing 13 and the bearing tap 15. In a conventional concrete mixer this bearing tap is fixed directly to the bottom ofthe drum.

The sieve 20 and the additional sieve 24 can be manufactured with different mesh size to meet all demands, i.e. from the finest sand to shingle for court-yards and pathways.

The sieving operation is performed in such a way that unsorted sand is poured into the drum through the opening 16. The drum is rotated around its centre axis 5 by means of said motor 3, which pref erablycan have two speeds, of which the lower one is intended for concrete mixing and the higher one for gravel or sand sieving. For instance, a two speed pulley transmission can be provided between the motor 3 and the gear meshing with the toothed gear ring 4. When the drum rotates the work up angle is adjusted so that optimal work up is achieved, said drum being positioned by tilting it around the centre axis 6 by means of the handle 8. Practical attempts have shown that the optimal work up angle is somewhat more horizontal than that at concrete mixing.The sieved sand flows out through the bottom of the drum via the hole 17 at the big base 22 of the sieve and down in for instance a wheel-barrow 1 placed under the drum. Thereafter, the unsieved rests are tipped out of said drum in the same way as when concrete is emptied by moving the handle 8 forward, whereby the drum is tilted around the centre axis 6.

The number of tube sections of said insert is not limited to four as is shown in the drawings, but can be chosen with regard to the form and length of said siev. Also, the form of both siev and tube sections is not restricted to that shown in the drawings. For instance, the siev can be cylindrical or hemispherical, or have another form.

When the drum is to be used for concrete mixing the sieve means is removed and a cover is placed over said hole by means of said screws and said nuts or any other fastening means. At least one additional shovel 32 is provided on the inner wall of the drum to lift up the sand and let it fall down over the sieving means 18 with the said sieve 20.

The after each other coaxially arranged above mentioned tube sections are provided to increase the effect of said device, so that the sand which has passed through the sieve does not flow back into the drum, but flows into one of said tube sections and follows the succeeding tube sections out of said drum.

The device according to the invention can be provided with a vibrator, but the natural vibrations which are generated in a concrete mixer is usually enough to vibrate the sand at the sieving operation.

The sieving means must be dismountable so that the insert can be made free from the sieve itself for cleaning purposes.

The invention can of course be modified within the scope ofthe accompanying claims.

Claims (9)

1. Combined sieving and mixing device comprising an on a frame around a first axis rotatable and around a second axis tiltable drum having an opening through which said first axis extends, characterized in that said drum in its bottom opposite said opening is provided with a removable section, in the place of which sieving means can be placed.

2. Device according to claim 1, characterized in that said sieving means consists of an into said drum extending frustoconical sieve the big base of which is open and fastened at the bottom wall of said drum and the little base of which is closed.

3. Device according to claim 2, characterized in that said sieving means further has an insert consisting of several on a frame fastened collecting means.

4. Device according to claim 2 or 3, characterized in that said sieve has a non-circular section.

5. Device according to claim 3 or4, characterized in that said collecting means consists of coaxially succeeding tube sections, one end of which is connected to said frame along the periphery of said sieve and the opposite ends of which are disposed in substantially the same plane.

6. Device according to any of claims 1-5, characterized in that said sieving means is provided with in the longitudinal direction of said sieve (20) extending projections.

7. Device according to any of claims 1-6, characterized in that at least one shovel is provided on the inner wall of said drum, said shovel being so placed that it during the rotation of said drum at sieving passes the lowest point of said drum.

8. Device according to any of claims 1-7, characterized in that an additional sieve can be placed in said opening of said drum to firstly achieve a rough sieving, said sieve being provided on its inner side with shovel means.

9. A combined sieving and mixing device, substantially as hereinbefore described with reference to any one of the embodiments shown in the accompanying drawings.