Patent Publication Number: US-3879156-A

Title: Molding machine with a sand scraper

Description:
United States Patent 1191 Buhrer et al.  
 1451 Apr. 22, 1975 [73] Assignee: said Buhrer, by said Keller 22 Filed: Mar. 12.1973  
  211 Appl.N0.:340,205  
 [30] Foreign Application Priority Data Mar. 16, 1972 Switzerland .1 3920/72 [52] US. Cl 425/218; 164/192 [51] Int. Cl B28b 13/02 [58] Field of Search 164/192, 193, 194, 195, 164/188, 190, 217, 325, 326, 327, 197, 198,  
 1.442.122 l/1923 Brown 425/218 1,836,007 12/1931 Bigton..... 425/219 X 3,326,145 6/1967 Austin 425/218 3,371,136 2/1968 .lohannsen 425/218 X 3,487,508 1/1970 Baumgartner 425/219 Primary E.\&#39;aminerFrancis S. Husar Assistant Examiner-John S. Brown Attorney, Agent, or FirmToren, McGeady and Stanger [57] ABSTRACT In a molding machine, sand is precompacted into mold halves located on a turntable and a scraper is arranged above the mold halves to remove any excess sand. The turntable and the scraper are each mounted for rotation about a different shaft. A gear arrangement is provided in engagement with the shafts for rotating the turntable and scraper in opposite directions. Preferably, a plurality of scrapers are attached to the shaft in equiangularly spaced relation and the scrapers include scraper blades which are removable from a scraper support and are adjustable in height relative to [56] References Cited the: mold ham UNITED STATES PATENTS 960,968 6/1910 Leamon 425/218 6 2 Drawmg figures m l l 1 I 16 l h ICIII.  
 PATENTEUAPRZEWS I 3,879,156  
 &#39; snaa&#39;reggg MOLDING MACHINE WITH A SAND SCRAPER SUMMARY OF THE INVENTION The present invention is directed to a molding machine with a scraper for removing excess sand from mold units and, more particularly, it concerns the arrangement of a turntable on which several mold units can be supported so that they are first filled with sand and then precompacted and the excess sand is removed by a scraper rotating in the opposite direction to the turntable before the final compaction of the sand is effected.  
  In supplying molding sand from a distributor into mold box halves, an excess of sand is supplied and must be scraped off to a predetermined height by a scraper member between the precompaction and final compactionof the sand.  
  It has been known to use a molding machine onto which an empty mold box is introduced by a crossmovable empty-box unit and is placed on a pattern unit of the molding machine. With the mold box in place, the molding sand is filled and vibrated into the box and the empty-box unit is removed with a sand scraper, attached to the empty-box unit, scraping off the excess sand. To compact the sand in the mold, another crossmovable finish-box unit equipped with a pressing head is moved over the mold to carry out the final compaction and then the mold is lifted off and moved away from the molding machine.  
  In another known molding machine, an empty mold box is supplied to a pattern unit, the box is lifted by a pressing piston ofthe pattern unit and is filled with sand from a charging device. Next, a pressing head mounted on a moving mechanism on which a tiltable sand scraper is secured, is moved over the mold transversely of the molding machine. During this movement cycle, the scraper removes excess sand from the mold. The final compaction of the mold is then carried out after which the pressing head is moved away from the mold. At the same time, the sand scraper is located in what is called a cutting position, so that, as the pressing head is removed, any sand left over from the final compaction is removed.  
  Known sand scrapers are not usable with molding machines having several pattern units located on a turntable, because the excess sand is thrown onto the following mold box during the scraping operation.  
  Therefore, the primary object of the present invention is to provide a molding machine with a sand scraper so that excess sand can be removed from a mold box located on one of a plurality of pattern units positioned on a turntable without experiencing the problems faced in conventional molding machines. Further, the scraper and the turntable are arranged to perform simultaneous rotary movements so that the scraping operation is performed between the precompaction and final compaction of the sand in the mold box.  
  Accordingly, based on the present invention, a gear arrangement is incorporated into the molding machine so that the shafts supporting the turntable and the scraper can be rotated in opposite directions with the scraper sweeping across the top of the mold box as it is moved from the precompacting position to the final compacting position.  
  The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.  
 BRIEF DESCRIPTION OF THE DRAWING In the drawing:  
  FIG. 1 is a schematic representation in vertical section of a molding machine including a sand scraper and a sand distributor, embodying the present invention; and  
 FIG. 2 is a view taken along line [-1 in FIG. 1.  
 DETAILED DESCRIPTION OF THE INVENTION Inthe drawing a portion of a molding machine is shown in a simplified manner including a turntable 12 supporting a plurality of pattern units 17 and rotating about a vertical shaft 22. A mold box 2 is placed on a pattern unit 17 and is filled with precompacted molding sand 18 and forms one casting mold half 13. In its precompacted state, the molding sand extends upwardly from the upper edge 6 of the mold box 2 by the combined distances 3 and 8. The distance or dimension 3 represents the height of the excess sand. while the distance or dimension 8 represents a predetermined dimension of the spacing of a scraping edge on a sand scraper 1 above the upper edge 6 of the mold box.  
  As can be seen in the drawing, the sand scraper 1 includes a fiat section support member 11 having a curvilinear contour as viewed in the horizontal plane shown in FIG. 2 and partially enclosing the contour of the mold box. The support member 11 is mounted on a frame 15 secured to a hub 16 and the frame is formed of sectional shaped material. The hub is fixed to a column or shaft 5. As indicated schematically, a gear 20 is provided on the shaft 5 and another gear 21 is provided on the shaft 22 for the turntable I2 and the gears 20, 21 are arranged in meshed engagement so that the turntable is movable in the counterclockwise direction represented by the arrow 9 and the shaft 5 is movable in the clockwise direction represented by the arrow 4. Alternatively, the directions of rotation of the turntable l2 and of the scrapers I attached to the shaft 5 can be reversed.  
  The support member 11 is arranged so that its flat section extends in the vertical direction and the scraper edge or strip 7 is attached to its lower narrow edge facing downwardly toward the upper edge 6 of the mold box 2. Preferably, the scraper edge 7 is attached to the support member 11 so that it is removable and adjustable in height relative to the upper edge 6.  
  It is possible, in relation to the molding cycle, to provide a plurality of scrapers 1 on the shaft 5 so that during one complete cycle of rotation of the shaft each of the scrapers is moved into the operating position. In the embodiment shown, two diametrically arranged scrapers l, l are provided each having a scraper edge 7 with the scraper edges being pivoted into operation by means of a feed device 14 introducing the mold boxes 2&#39; to the turntable.  
  In the range of the scraper strips, liftable and lowerable filling frames 10 are supported on the shaft 5. Though not shown, a sand distributing device is located above the filling frames 10.  
  In the operation of the molding machine, after the mold box has been placed on the pattern unit and filled with sand the sand is precompacted and the pattern unit is moved in the counterclockwise direction 9 for transporting the mold box from the precompacting operation to the final compacting operation. Simultaneously with the rotary movement of the pattern unit, due to the gear arrangement 20, 21, the sand scraper is moved in the clockwise direction 4 and the quantity of excess sand in the path of the scraper edge 7 is removed in the relative movement between the scraper and the pattern unit. At the same time, another pattern unit and an additional mold box are brought into the filling position.  
  In accordance with the present invention, a number of advantages are attainable, for example, in the mold ing cycle no unproductive cycle movements take place and several pattern units can be served by the sand scraper. Further, the excess sand removed by the scraper is directed away from the zone of the pattern unit which is moved into the filling position. Due to the opposite rotary movements of the turntable l2 and the scraper l, a special sliding relative movement occurs between the mold surface and the scraper so that the excess sand is scraped off gradually from the mold without any accumulation of sand at the scraper edge, which accumulation might cause a tearing action on the mold surface.  
  While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles. it will be understood that the invention may be embodied otherwise without departing from such principles.  
 We claim:  
  1. In a molding machine including a sandscraper, a turntable, a plurality of pattern units mounted on said turntable, and mold boxes positioned on said pattern units, so that sand filled into said mold boxes can be precompacted followed by the removal of any excess sand and then the sand finally compacted, wherein the improvement comprises a first shaft rotatably support ing said turntable for rotation in a horizontal plane, a  
 second shaft spaced laterally from said first shaft and outwardly from the outer periphery of said turntable, means for filling sand into said mold boxes located above said mold boxes so that the sand is filled to a level extending upwardly from the upper edge of said mold boxes, at least one scraper connected to and extending outwardly from said second shaft for rotation in a horizontal plane, the horizontal plane of rotation of said scraper being located below said filling means and above the upper edges of said mold boxes in the range to which the sand is filled into said mold boxes, a first gear connected to said first shaft, a second gear connected to said second shaft and arranged in meshed engagement with said first gear so that, as said gears ro tate, said first and second shafts are rotated in opposite directions so that said scraper moves relative to said turntable and sweeps across above the tops of said mold boxes for removing sand filled into said mold boxes at a level above the upper edges of said mold boxes, and said filling means comprises a filling frame vertically displaceably mounted on said second shaft.  
  2. In a molding machine, as set forth in claim I, wherein a plurality of equiangularly spaced scrapers are attached to said second shaft.  
  3. In a molding machine, as set forth in claim 1, wherein said scraper includes a vertically arranged support member attached to said second shaft and a scraper edge removably secured to the lower end of said support member.  
  4. In a molding machine, as set forth in claim 3, wherein said scraper edge is adjustable in height relative to said turntable.  
  5. In a molding machine, as set forth in claim 3, wherein said support member is formed ofa flat section shaped in a curvilinear contour in a horizontal plane.  
  6. In a molding machine, as set forth in claim 5, wherein, at the commencement of the scraping operation, said scraper is located laterally outwardly of said pattern unit and extends forwardly of said pattern unit in its path of movement on said turntable.