US2998935A - Grinding-mixing mill for foundry sand - Google Patents

Grinding-mixing mill for foundry sand Download PDF

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Publication number
US2998935A
US2998935A US826990A US82699059A US2998935A US 2998935 A US2998935 A US 2998935A US 826990 A US826990 A US 826990A US 82699059 A US82699059 A US 82699059A US 2998935 A US2998935 A US 2998935A
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grinding
wheels
sand
spider
grinding wheels
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US826990A
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English (en)
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Pellizzetti Italo
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C15/00—Disintegrating by milling members in the form of rollers or balls co-operating with rings or discs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C15/00—Disintegrating by milling members in the form of rollers or balls co-operating with rings or discs
    • B02C15/14—Edge runners, e.g. Chile mills
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C5/00—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose
    • B22C5/04—Machines or devices specially designed for dressing or handling the mould material so far as specially adapted for that purpose by grinding, blending, mixing, kneading, or stirring
    • B22C5/0409—Blending, mixing, kneading or stirring; Methods therefor
    • B22C5/0422—Devices having a fixed receptable with rotating tools, some or all of these tools being rolls or balls loosely mounted on their axis or loose balls in contact with the side wall or the bottom of the receptacle, e.g. with aerating means; "Devices of the Muller type"
    • B22C5/0427—Devices having a fixed receptable with rotating tools, some or all of these tools being rolls or balls loosely mounted on their axis or loose balls in contact with the side wall or the bottom of the receptacle, e.g. with aerating means; "Devices of the Muller type" having only one vertical tool-driving shaft

Definitions

  • Foundrymen have therefore devoted, for many years, their efforts towards the development of grinding-mixing mills or mullers for the satisfactorily processing foundry sand in order to obtain a material of satisfactory physical properties which are usually predetermined depending upon the nature of the casting.
  • the grinding wheels are of excessive weight and require an excessive power, and moreover tend to break the silica granules giving rise to increased dust formation resulting in lower permeability of the sand;
  • the sand is not ground and mixed with constant uniformity, the action of the ploughshares nearly always forms heaps or valleys, thereby deforming the ideal level of the material to be processed.
  • the principal object of this invention is to provide a grinding-mixing mill constructed to eliminate the above mentioned disadvantages.
  • a grinding-mixing mil-l of the type comprising a circular vat, at least one circular grinding wheel rolling on the vat bottom and means for carrying along the grinding wheel over an annular path on the bottom, the latter means including a central vertical driving shaft, is characterized in that the grinding mill is supported by a shaft eccentric with respect to the driving shaft and is positively rotated, whereby the grinding wheel, while performing its annular travel on the bottom, rotates at the same time about the eccentric shaft.
  • the grinding wheel is mounted and freely rotatable on a radial spindle on the eccentric shaft in order to revolve about the cocentric shaft.
  • FIG. 1 is an axial vertical sectional view of a grinding-mixer showing the most advantageous embodiment of this invention
  • FIG. 2 is a fragmentary plan view of FIG. I;
  • FIG. 3 is a diametrical sectional view of a grinding wheel employed on the grinding mixer shown in FIG. 1;
  • FIG. 4 is a side view of FIG. 3, and
  • FIG. 5 is a diagram illustrating the operative path of a grinding wheel on the bottom of the grinding mixer shown in FIGS. 1 and 2.
  • FIG. 6 is a view showing the stop structure claimed herein.
  • the mullers according to the invention comprises a central tubular column secured to a circular bottom 2.
  • the column supports, through the interposition of a bearing 3 enclosed by its top end, and a bearing 21 on the hub of a sun-wheel 4 secured to a centering bridge 5-, a rotatable hollow spider 19.
  • the centering bridge is diametrically arranged and bolted at both ends to a top of the cylindrical circumferential wall 6 which forms, together with the bottom 2, the vat of a grinding mixer.
  • a driving shaft 7 extends axially through the central column 1 and is driven by an electric motor 8 secured beneath the bottom 2.
  • the top end of the shaft 7 is formed with spline grooves 9 for splining thereto a pinion 1i] transmitting motion through two planet Wheels 11, 11' at a desired ratio to two driving toothed wheels 12, 1'2 splined to shafts -13, 13, respectively.
  • the latter are rotatably supported by the diametrically opposed arms of the spider 19 and extend downwardly parallel with the shaft 7.
  • the lower end of each of the shafts 13, 13' has rigidly attached thereto a cross-member 14, 14", respectively.
  • the planet wheels 11, 11 are fast with two other planet wheels 15, 15' which mesh with the sunwheel 4.
  • Trunnions 20, 20' for the planet wheels 11, 15 and 11', 15' are rotatably supported by the arms of the spider 19.
  • the whole epicyclicgearing described above is housed in the cavity in the spider.
  • the shafts 13, 13 each drive a respective pair of coaxial grinding wheels 16, 16' and 17, 17' situated at diametrically opposed positions with respect to their shafts 13, 13', respectively.
  • one pair of grinding wheels 16, 16' is angularly displaced through to the other pair 17, 17', as shown by FIG. 2. Consequently, it ensues from the above example that these four grinding wheels each perform the above-mentioned twelve revolutions a total of forty-eight revolutions are performed by the four grinding wheels about their respective shafts 13, 13 on each revolution of the spider 19.
  • the individual grinding wheels are each supported by their respective cross-members 14, 14' by means of a respective bell-crank lever each having two. arms 18, 24 fulcrurned to one end of the respective cross-member.
  • the arm 18 of each of the bell-crank levers has fast therewith a respective spindle 38, FIG. 3, for the grinding wheel it supports.
  • the individual spindles extend radially with respect to their respective shaft 13, 13'. 'In order to effect the desired pressure by the grinding wheels on the sand four tension springs 22, one for each grinding wheel, protected by a telescopic sheath, are fastened at one end to a bracket 23 fast with the respective crossmember 14, 14, and at their other end to the respective bell-crank arms 24 of the above mentioned bell-crank levers.
  • the traction force of the springs 22 is adjusted by means of nuts and lock-nuts and threaded spindles 25 extending through studs 26 pivoted to the bracket 23 and arm 24, respectively. Consequently, the springs 22 constantly urge the respective grinding wheels 16, 16, 17, 17' towards the bottom 2, while resiliently opposing any upward movement due to sand heaps exceeding a normal level AA or any foreign body. stones or the like.
  • the bell-crank levers 18, 24 are each formed with a support 28 having an adjustable stop screw 27 abutting its respective cross-member 14, 14'. The grinding wheels 16, 16', 17. 17 can thereby be kept in a.
  • levelling blades 29 are arranged ahead of their respective grinding wheels at the height of the maximum sand let'el denoted on the drawing. by the line A-A.
  • the leveling blades 29 are attached to their respective cross-members 14. 14'. It will be clear that with this arrangement the grinding wheels will travel on the sand while it is constantly at the same level. whereby grinding and mixing are improved in uniformity in-that they are carried out by the grinding wheels at a constant pressure.
  • FIG. 1 It will be seen from FIG. 1 that the wall 6 and column 1 are at right an les to the bottom 2, so that the grinding wheels 16. 16, 17. 17 because of their circular shape would normally leave, during their revolutional movement, unprocessed sand adjacent the wall and column.
  • Two annular members 30, 30' of concave arcuated cross-sectional shape extend throughout the inner circumference of the bottom 2 and throughout the outer circumference of the bottom, respectively, to eliminate this possibility.
  • These annular members together with the bottom 2 form an annular channel having arcuate sides and simultaneously determine the width B (FIGURES 2 and of a track on the bottom 2 which is proportioned to the axial spacing of the grinding wheels in each pair, whereby all the sand is acted upon by the grinding wheels.
  • the arrows a, a indicate the movement of the spider 19 and, the arrows b, b and c, 0' indicate the movements of the grinding wheels 16, 16' and 17, 17,, respectively, about the shafts 13, 13' denoted by dotted lines.
  • the centering bridge 5, which is fully shown, is bolted to supports 31 fast with the vat wall 6 by screws 32 visible at the middle of the centering bridge 5. The screws attaching the sun-wheel 4, to the bridge 5 are shown by dotted lines.
  • the hollow spider 19 enclosing the whole gearing is made up of two sections, namely a lower box and a lid shown in sectional view in FIG. 1, sealed together by screws 35, FIG. 2.
  • FIG. 3 is shown the body 34 of one of the grinding wheels 16, 16', 17, 17' which is formed with a central hub 35 housing bearings 36, 37 for the spindle 38 to allow free rotation of the grinding wheel when the latter frictionally rolls on the sand disposed on the bottom 2 of the grinding mixer.
  • the body 34 of the grinding wheel comprises two spaced flange portions both integral with the hub 35 and a felloe 45 to form a hollow construction of lightest possible weight consistent with the work to be performed by the grinding wheels.
  • the felloe 45 has fitted thereon a rim 39 made of steel or other suitable material coated by a thick hard rubber cover 40 contacting the sand for grinding and mixing purposes. It will be understood that the grinding wheel need not be replaced in case of wear. When the cover 40 is worn it is sufficient to replace the rim unit 39, 40 similiarly to solid tires of lorry wheels.
  • the bearings are protected at the front by a tight sealing lid or cap 41 fast with the grinding wheel body and at the rear by a special seal.
  • a logarithmic spiral groove 42 is formed in the front face of the hub 35.
  • a rubber seal 43 is inserted into the groove.
  • the rubber seal is disposed in sliding contact with a polished face of a flange 44 fixed to the spindle 38. It will be seen from FIG. 4, showing a front view of the spiral, that since the spiral is directed opposite to the sense of rotation of the grinding wheel, any foreign body coming into contact with the spiral seal 43 is regularly rejected outwardly without any possibility of access to the bearing 36.
  • FIGURE 5 illustrates diagrammatically, by way of explanation the path followed by one grinding wheel, such as wheel 16, during one revolution of the spider 19, where provision is made for the grinding wheel to perform twelve revolutions in accordance with the above described example, in order to supply a demonstration of the above object of fully scanning the whole width B" of the bottom 2. Since four grinding wheels are provided which travel over four distinct paths similar to the path shown in FIG. 5, it may be said that the bottom is exposed to the action of the grinding wheels throughout, so that the sand is methodically and efficiently processed.
  • a stationary vat having means defining a horizontal circular bottom, a stationary tubular column vertically extending from a central zone on said bottom, a vertical driving shaft arranged for concentric rotation in the column, a hollow spider rotatably supported at the top end of the column, said spider including two hollow radial arms extending in opposite directions, two vertical shafts rotatably depending from a respective one of said hollow arms and each disposed at a position eccentric to the driving shaft, an epicyclic gearing enclosed by the spider adapted to rotate the spider with respect to, the column and the two eccentric shafts with respect to their respective arms on rotation of the driving shaft, for each eccentric shaft a cross member fixed on the lower end of a respective eccentric shaft, for each cross member a pair of hell crank levers fulcrumed at opposite ends of the cross member each having a first arm upwardly extending.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • Crushing And Grinding (AREA)
  • Mixers Of The Rotary Stirring Type (AREA)
  • Motorcycle And Bicycle Frame (AREA)
  • Grinding Of Cylindrical And Plane Surfaces (AREA)
US826990A 1958-07-19 1959-07-14 Grinding-mixing mill for foundry sand Expired - Lifetime US2998935A (en)

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IT592906 1958-07-19

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DE (1) DE1824410U (fr)
FR (1) FR1229511A (fr)
GB (1) GB866640A (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3334822A (en) * 1963-12-09 1967-08-08 Nat Eng Co Mulling machine
US3454232A (en) * 1963-05-10 1969-07-08 Robert A M Ronceray Mixer-grinder,especially for foundry sands
EP0024814A2 (fr) * 1979-09-01 1981-03-11 Taiyo Chuki Co., Ltd. Pétrisseur pour matériaux particulaires ou granulés
CN104029295A (zh) * 2014-05-28 2014-09-10 浙江立鑫高温耐火材料有限公司 一种混碾装置
CN104028354A (zh) * 2014-05-28 2014-09-10 浙江立鑫高温耐火材料有限公司 一种耐火泥的混碾装置
CN104475197A (zh) * 2014-10-09 2015-04-01 苏州可纳粉体技术有限公司 一种多分散盘双轴立式透平研磨分散机
CN111054886A (zh) * 2020-02-24 2020-04-24 三门前庭机械科技有限公司 一种铸造用砂混合装置
CN118305317A (zh) * 2024-06-07 2024-07-09 蓬莱市超硬复合材料有限公司 一种硬质合金粉料湿法研磨设备

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US285538A (en) * 1883-09-25 Ore-crusher
US787018A (en) * 1902-11-28 1905-04-11 Julius Wuestenhoefer Pendulum-mill.
US1158283A (en) * 1914-11-25 1915-10-26 Henry Urson Prindle Pulverizing-mill.
US1910028A (en) * 1930-07-23 1933-05-23 Herbert S Simpson Muller
US2701106A (en) * 1950-04-26 1955-02-01 Macchine Ind Dolciaria Carle & Machine for the final working up of chocolate

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US285538A (en) * 1883-09-25 Ore-crusher
US787018A (en) * 1902-11-28 1905-04-11 Julius Wuestenhoefer Pendulum-mill.
US1158283A (en) * 1914-11-25 1915-10-26 Henry Urson Prindle Pulverizing-mill.
US1910028A (en) * 1930-07-23 1933-05-23 Herbert S Simpson Muller
US2701106A (en) * 1950-04-26 1955-02-01 Macchine Ind Dolciaria Carle & Machine for the final working up of chocolate

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3454232A (en) * 1963-05-10 1969-07-08 Robert A M Ronceray Mixer-grinder,especially for foundry sands
US3334822A (en) * 1963-12-09 1967-08-08 Nat Eng Co Mulling machine
EP0024814A2 (fr) * 1979-09-01 1981-03-11 Taiyo Chuki Co., Ltd. Pétrisseur pour matériaux particulaires ou granulés
EP0024814A3 (en) * 1979-09-01 1981-05-06 Taiyo Chuki Co., Ltd. Kneader for particulate or granular materials
CN104029295A (zh) * 2014-05-28 2014-09-10 浙江立鑫高温耐火材料有限公司 一种混碾装置
CN104028354A (zh) * 2014-05-28 2014-09-10 浙江立鑫高温耐火材料有限公司 一种耐火泥的混碾装置
CN104475197A (zh) * 2014-10-09 2015-04-01 苏州可纳粉体技术有限公司 一种多分散盘双轴立式透平研磨分散机
CN111054886A (zh) * 2020-02-24 2020-04-24 三门前庭机械科技有限公司 一种铸造用砂混合装置
CN111054886B (zh) * 2020-02-24 2021-03-09 临海市兴业精密铸造有限公司 一种铸造用砂混合装置
CN118305317A (zh) * 2024-06-07 2024-07-09 蓬莱市超硬复合材料有限公司 一种硬质合金粉料湿法研磨设备

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FR1229511A (fr) 1960-09-07
DE1824410U (de) 1961-01-05
GB866640A (en) 1961-04-26

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