US3113923A - Self-propelled brushes for reciprocating sieves - Google Patents

Description

Dec. 10, 1963 J. D. BINGHAM 3,113,923

SELF-PROPELLED BRUSHES FOR RECIPROCATING SIEVES Filed May 11, 1962 2 Sheets-Sheet 1 Dec. 10, 1963 J. D. BINGHAM SELF-PROPELLED BRUSHES FOR RECIPROCATING SIEVES Filed May 11, 1962 2 Sheets-Sheet 2 United States Patent Office 3,113,923 Patented Dec. 10, 1963 3,113,923 SELEPROPELLED BRUSHES FOR RECIPROCATING SIEVES John D. Bingham, Bramhall, England, assignor to Henry Simon Limited, Stockport, England, a company of Great Britain Filed May 11, 1962, Ser. No. 194,061 Claims priority, application Great Britain June 30, 1961 1 Claim. (Cl. 209-388) It is common practice to keep the covers of reciprocating sieves clean by means of brushes which extend over the full width of the sieve and travel forwards and backwards beneath the cover and which are actuated by the motion of the sieve. Usually these brushes are pivotally mounted to and above a carriage sliding on a rail placed longitudinally below the sieve, the brush stock having two rows of bristles on opposite sides inclined to each other at an angle rather less than 180 above the stock. When travelling, the vertical axis of the brush stock is inclined forward about its pivot so that the rear row of bristles contacts the cover at an acute angle. The brush cannot move relative to the sieve in the direction in which the bristles would dig into the cover but is free to slide forward in the other direction. Such brushes are turned over at the end of their travel by fixed stops or ramps which engage the brush at a position above its pivot.

In order that all parts of such brush assemblies shall work freely in conditions where they are continuously showered by falling powdered material, large working clearances are provided at the pivots and carriage supports, but it is known that these clearances have the disadvantageous effect of permitting such a brush to twist relative to its pivot axis so that it is not parallel with the ends of the sieve, and consequently when the brush turns over, a tapering strip along the end of the sieve is left uncleaned, thus reducing the effective area of the sieve. To overcome this effect it has been proposed to cause the carriage to slide on a spaced pair of parallel rails but it has been found that if such rails become bent or damaged by handling they cause the brush carriage to jam and remain motionles.

An object of the present invention is to provide an improved sieve brush which mitigates the aforesaid disadvantages.

According to the invention, a self-propelled brush for a reciprocating sieve of a type comprising a carriage sliding on a single rail placed longitudinally beneath the sieve and having pivoted above and to the said carriage and extending transversely across the sieve a brush stock having two rows of tufts of bristles on opposite sides inclined to each other, is provided on each of the sides facing the direction of travel with two outwardly projecting carriage extensions which are substantially parallel to the centres of the bristle tufts and so spaced apart that when the end of any such extension moves into contact with a matching turn-over ramp on the sieve frame a pivoting point is established about which the brush will twist in a horizontal plane until it is parallel With the associated sieve frame end member with the other related extension end also in engagement with a matching turn-over ramp so that further movement of the brush will cause it to turn over and thus be free to move in the opposite direction.

An embodiment of the invention will now be described with reference to the accompanying drawing, in which:

FIGURE 1 is a longitudinal section through a sieve incorporating a brush in accordance with the invention,

FIGURE 2 is an exploded perspective view of a brush, and

FIGURE 3 is a side elevation of the brush shown in FIGURE 1.

FIGURE 4 is a plan view of the sieve and brush of FIGURE 1.

The sieve shown in FIGURE 1 comprises a frame 1 of which the end frame members 2 are shown in section. Stretched over the frame is a sieve cover 3 below which is provided a rail 4 held to the end frame members 2 by brackets 5. The brush, which is shown more clearly in FIGURES 2 and 3, comprises a carriage 6 formed by a nylon block which is grooved on its underside to locate on the rail 4. At its longitudinal centre the block 6 supports a transverse pivot-rod 7 which extends laterally to engage pivot holes in dependent lugs 8 of a brush-stock locating element 9 that has on each side and at right angles to the pivot rod two laterally spaced longitudinally projecting extensions 10 which are bent upwards at a small angle but terminate at downwardly turned hookshaped ends 11 arranged to form smooth cam surfaces to arrest and turn over the brush when both the extension ends of one side of a brush engage ramp surfaces 12 on the brackets 5. Secured by screws 15 and Washers 16 to the element 9 is a brush-stock member 17 spanning the associated sieve and having on each side that faces the directions of movement a row of closely associated tufts 13 of bristles which are inclined upwardly at a small angle so that between the two rows of tufts of bristles an angle somewhat less than is formed, the lengths of the bristles being such that one or other row will engage the sieve cover 3 according to which way the brush is tilted. A groove in the upper surface of the brush stock 17 houses a weight-bar 14 to stabilise the brush in either of its operative positions.

In operation, when such a sieve brush approaches the sieve-frame end member 2, one or other of its leading side carriage extensions 11 will engage one of the turnover ramps 12 on the sieveframe 2, as shown in FIG- URE 4, to form a pivot point 18 about which the brush will twist in a horizontal plane to an extent A until it is parallel with the sieve frame member and has both leading side carriage extensions 11 engaged by turn-over ramps 12. This is the position shown in broken line at the left of FIGURE 1. Further advancement of the brush will cause it to turn over in such a Way that the uplifted cleaning bristles will be parallel with and in close proximity to the sieve-frame member over the full width of the sieve, irrespective of the amount by which the brush can twist by virtue of the working clearances between its relatively moving parts. In such brush gear therefore large Working clearances can be permitted to combat possible dust fouling of the pivots and slide.

What I claim is:

A self-propelled brush for a reciprocating sieve having a single rail disposed longitudinally beneath the sieve, said brush including a carriage comprising a block having a groove receiving said rail to slidably mount said carriage thereon, a brush stock locating element having a central portion pivotally mounted on said block and extending transversely of said sieve, a brush stock secured to said central portion, a row of bristle tufts projecting from opposite sides of said stock in diverging inclined relationship, two laterally spaced longitudinally projecting extensions on each side of said central portion, the extension on each side being substantially parallel to the center lines of the bristle tufts, each extension terminating in a downwardly turned hook-shaped end to provide a smooth cam follower surface and a turn-over ramp fixed at each end of the travel of said brush, each ramp providing spaced cam surfaces on opposite sides of said rail, said cam surfaces being in alignment with said extensions, whereby movement of said cam follower surfaces into engagement with said cam surfaces will first move said locating element and brush stock to a position substantial- 1y at right angles to said rail, further movement of said References Cited in the file of this patent cam follower surfaces in engagement with said cam sur- FOREIGN PATENTS faces causing pivotal movement of said locating element and brush stock to move one row of bristle tufts out of g ggz 3:: 3. -t 1 r J engagement W1 h said sleve and e other rovv of bnst e 5 693,811 Great Britain July 8, 1953 tufts into engagement with said sieve.

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