US2115384A - Permanent mold machine for making tappets - Google Patents

Description

April 26, 1938. J. 1.. 005m. 2,115,384

PERMANENT MOLD MACHINE FOR MAKING TAPPE'I'S Filed July 29, 1935 5 Sheets-Sheet l fi ia filllmlllllillllllllllll //IA EEK KQIIIIIIIIIIA IN VEN TOR.

Ta-5677a Z. ZosZaZ.

fiwmaw.

ATTORNEY April 26,1938. J. 1;. DOST/4 2, 15 384 PERMANENT MOLD MACHINE FOR MAKING TAPP ETS I 7 Filed July 29, 1935 s Sheets-Sheet 2 INVENTOR. Jase7& 1. D0 5542'.

ATTORNEY-6.

April 26, 1938. J. L; DOSTAL PERMANENT MOLD MACHINE FOR MAKING TAPFETS Filed July 29, 1935 3 Sheets-Sheet 5 INVENTOR. v J06c %-Z. flosial.

A TTORNEY-S.

Patented Apr. 26, 1938 UNITED STATES PERMANENT MOLD MACHINE FOR MAKING I TAPPETS Joseph L. Dostal, Birmingham, Mich., assignor, by mesne assignments, to Eaton Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application July 29, 1935, Serial No. 33,717

3 Claims.

This invention relates to permanent molding machines and more especially to the type of machine comprising a conveyor which carries a plurality of pairs of cooperating mold sections, which sections, when brought together, provide mold cavities in which metal articles may be cast.

The principal object of the invention is to improve the art of producing cast iron articles having a hard and wear resistant surface over at least certain portions of such articles.

A further object is to provide apparatus for producing a one-piece hollow cast iron tappet so accurately to size as to minimize the amount of finishing operations required.

A further object of the invention is to so cast a hollow, one-piece tappet, closed at both ends, that one end, the cam engaging portion, will be chilled to produce a hardness so as to afford the desired wear resistance, Rockwell scale C, and the periphery will be chilled through to the core so as to have a slightly lesser hardness, and that the opposite end of the tappet will be correspondingly softer and readily machinable so that it may be readily bored and threaded to receive an adjusting element.

Another object is to produce a tappet having a hard cam engaging and peripheral surface and a correspondingly softer end portion banded by harder metal having higher tensile strength than said soft machinable portion so as to prevent dis-' tortion and expansion of the adjustment end of the tappet as a nut for the adjusting screw is tightened down against the tappet top.

A further object is to provide a cast tappet free from burned sand, particularly in openings or windows formed in the peripheral walls for the purpose of lightening the tappet.

It is also an object of the invention to provide a novel method of forming tappet windows of the type disclosed in my co-pending application Serial No. 33,719, filed July 29, 1935.

,Still another object of the invention is to pro- Vide a novel type of mold adapted to employ a core cover of sand or other refractory material for the purpose of producing relatively soft and machinable top portion of a tappet.

Another object is to provide a. novel means and method of locating and centralizing a core for forming the interior cavity of a hollow, barrel type tappet.

It is also an object of the invention to make provision for venting gases from the mold of the above type.

A further object is to provide a separate and cooled section of a mold for forming the cam engaging portion of a tappet.

A further object of the invention is to provide a sectional type mold constructed and arranged so as to have a cooling medium circulated through parts thereof.

Other objects, features and advantages will become apparent from the following description and appended claims. 7 I

For the purpose of illustrating the genus of the invention, typical concrete embodiments are shown in the accompanying drawings, in which:

Figure 1 is a top plan of a permanent molding machine adapted for casting a barrel type tappet in accordance with the principles of this invention; 4

Fig. 2 is an enlarged, fragmentary section taken in a vertical plane substantially n the line 2-2 of Fig. 1;

Fig. 3 is a fragmentary top plan, similar to Fig. 1, but on an enlarged scale, of a modified form of permanent molding machine constructed according to the principles of this invention;

Fig. 4 is a vertical section, on an enlarged scale, taken substantially on the line 4-4 of Fig. 3;

Fig. 5 is a central vertical section taken through one of the molds and on a radial plane through the axis of either of the molding machines shown in Figs. 1 and 3;

Fig. 6 is a substantially vertical, central section through a barrel type tappet, such section being taken approximately as indicated by the line 66 of this figure;

Fig.- 7 is a fragmentary, central vertical section of a modified form of mold adapted to be employed in casting an open top type of barrel tappet; and

Fig. 8 is a section taken on the line 8-8 of Fig. 7.

In carrying out the present invention, there may be provided an endless carrier, preferably in the form of a rotatable table l0, illustrated in Figs. 1 and 2 as carrying a plurality of molds l2. The table II! may be formed by securing to a horizontally arranged disc-like part l4, provided with a. center hub I 5 and a downwardly extending guide flange It at its periphery, a pluralityof partial sectors H, the latter together forming a circular ring extended outwardly from part H. A plurality of partial sectors 20, each provided with an upstanding flange 2| slightly spaced from the outer periphery thereof, are secured to each of the partial sectors I! to form a further circular ring extended outwardly from the ring formed by the partial sector l1. Bolts l8 may be employed for securing the partial sectors l1 and 26 together and to the disclike part I 4. A flange 2| is spaced from the periphery of the ring formed by the partial sectors 26 a sufficient distance to provide a ledge 22 of awidth equal to one-half of the width in a radial direction of the molds l2.

The rotatable table I 6 is Journaled through the hub l6 and a bushing 23 therein for rotation with respect to a shaft 24. The lower end of shaft 24 is supported at the center of a circular support plate 25 adapted to be mounted in stationary condition to a suitable base or support, not shown. The outer portion of the stationary support plate 26 is offset upwardly to provide an upstanding shoulder portion 26 terminating in an annular guide rib 21 adapted to be received in an annular channel 26 provided in the guide flange |6 of the rotatable disclike part l4. Inwardly, but adjacent the upstanding shoulder 26, the stationary or bed plate 25 is provided with a ledge 36 affording a horizontal bearing surface for a bearing 3| upon which a gear 32, fixed to the flange l6 of rotatable disclike part I4, is adapted to rotate.

' The gear 32 is provided with internally directed teeth 33 cooperable with a pinion 34 integral with or fixed to a pinion shaft 35 for the purpose of rotating the gear 32 to effect rotation of table I6. A gear mounting sleeve 36 is fixed to the shaft 35 and carries a bevel gear 31 adapted to be driven by a pinion 43 fixed to or integral with shaft 42. The gear casing 46 is provided for supporting bearings 38 for the gear mounting sleeve 36 and shaft 35 and bearing 4| for the pinion shaft 42. A coupling 44 connects the drive shaft 45 to pinion shaft 42 so that the rotatable table I6 may' be operated from any suitable v source of power, not shown, connected to the drive shaft 45. I

A disclike air shield 56 provided with a suitable central aperture 5| is supported from the upstanding flanges 2| of partial sectors 26. An upstanding collar 52 is provided at the margins of the central aperture 5| and encloses the lower end of a suction conduit 53 leading to an exhaust fan, not shown. The space between the elements l4, l1, and 26 and the air shield 56 constitutes a suction passage or chamber operating in conjunction with the suction conduit 53 and the exhaust fan associated therewith for drawing cooling air through the molds l2 and parts adjacent thereto. Openings 55 extend downwardly through the partial sectors 26 to the interior of a troughlike partial annulus 56 having openings 51 at the bottom thereof for each of a plurality of headers 66 secured thereto by means of bolts 6|. The headers 66 are each provided with a lug 62 cooperable with ears 63 formed on swingable mold carriers 64, 'a pivot pin 65 connecting the ears of each of the swingable mold carriers to the lugs 62 of headers 66. The swingable mold carriers 64 are each provided with'a passage 66 therethrough terminating in a curved conduit 61 having the axis of pivot pin 65 as a center and projecting through an opening 68 of header 66 so as to maintain communication at all times between the passages 66 of the swingable mold carriers and the interiors of the headers 66. A support 16, substantially of U-section, as viewed in Fig. 2, is fixed to the plate 25 and has bolted thereto a plurality of brackets 1|, one bracket being individual to each of the swingable mold carriers 64. To the upper end of each of the brackets 1| is pivotally connected a bell crank lever 12 provided with a journaled roller 13 engageable with a cam contact 14 provided on each of the swingable mold amass-1 carriers 64. Springs 16 extending between an arm 18 provided on each of the brackets 1| and an arm of bell crank levers 12 normally bias the rollers 13 into engagement with the outer marginal surfaces of the cam contacts 14.

The swingable mold carriers 64, in practice, swing about the pivot 65 outwardly through an angle of approximately 30 degrees when not engaged by the roller 13 or other operating means therefor. Rotation of the table l6 in a clockwise direction as viewed in Fig. 1, causes the cam contact 14 of each of the swingable mold carriers 64 to successively engage a cam 16 so as to swing the mold carriers 64 inwardly toward the shaft 24 and to close the mold sections and permit the rollers 13 of bell crank lever 12 and spring 16 yieldingly to maintain the mold sections in closed condition. The cam contacts 14 are provided with a beveled inner surface 11 engageable with a cam 16 beyond the series of rollers 13 so that a downwardly projecting lip on cam 18 will cause opening of the molds as the cam 18 causes outward swinging of the mold carriers 64 as indicated in Fig. 1. The cams 16 and 18 are carried by the support member 16.

Referring to Figs. 2, 5, and 6, the molds l2 are illustrated-I as comprising sections 66 and 6| separable with reference to a vertical parting line 62. The main mold sections 66 and 8| are each provided with a semi-cylindrical mold cavity 63 so that the two cavities form a cylindrical bore extending vertically and longitudinally through I each of the separable molds l2. A separate mold section 64 substantially in the form of a hollow piston, closed at the upper end 85 and provided with a cooling fin 86 so that the separate section forms the lower end of the tappet 65, is depicted in Fig. 5. A pin 81 extending from the stationary main mold section 8| may project through an opening 86 to determine the elevation of the separate section 84. A plurality of such openings 66 may be provided cooperable with the pin 61 so as to obtain slight variations in the lengths of the tappets produced. The separate section 84, which forms the bottom of the tappet 65, is hollow to form an air passage for the circulation of cooling air therethrough and, accordingly, its length is made several times its diameter in order effectively to cool the same than to attain the desired chill of the cam engaging end of the tappet 65. A permanent mold comprising two main sections separable along a vertical parting line and provided with impressions 83, enables the production of tappets very close to the finished diameter desired so as to eliminate as much grinding as possible on the outside surface of the tappet. The impression 83 in each of the mold sections 86 and 8| has projections 66 which form openings in the hollow tappet 65 of the desired size and shape and extend to the walls of such hollow tappets so as to communicate with a dry sand core 93 which forms the hollow interior of the tappet, thereby locating the core in diametrically correct position. A locating pin 64 may be provided in one of said projections for holding the core in the correct vertical position, opening 66 being provided in the core in a predetermined position to secure the correct vertical elevation of the core desired.

A permanent mold corrects several dimculties normally encountered in producing tappets in the ordinary sand mold. It is extremely diflicult to produce castings by the sand method in order to obtain close tolerances and eliminate much of the grinding required for finishing the outside surface of the tappets. It is also ditflcult in casting by the sand method to obtain clean castings free from burned-in sand, especially in the openings or windows 92 cast in the periphery of the tappet for the purpose of lightening the same. This burned-in sand is very diflicult and expensive to remove and undesirable in an internal combustion engine since the sand frequently loosens and causes scoring of the tappet or tappet guide as well as getting into the lubricating system of the motor so as to endanger bearings or other moving parts of an internal combustion engine.

In making the tappet 95 by the permanent mold method, the latter condition is entirely eliminated in the windows 92 of tappet 95, as such windows are formed by the integral projections 90 in the permanent mold sections and 8|, and due to the rapid chilling effect of the metal mold sections, the sandof the core 93 does not have a chance to burn in or on parts of the cast tappet.

Another disadvantage of the tappet-cast by the sand method is that it is impossible to obtain a hard peripheral surface and a soft top which is machinable so that it may be bored and threaded as indicated at 91 in Fig. 6 for the purpose of receiving an adjusting screw. With both the main mold sections 80 and 8i and the separate bottom section 84 of metal, both the cam engaging surface of tappet and the entire periphery of the cylindrical body portion of the tappet will be of chilled metal entirely through the wall pottions of the tappet to theinterior of the tappet or to the core 93 as long as the'mold sections 80, 8|, and 84. are kept in a sufficiently cool condition.

A top of the tappet may be made softer and more machinable in order more readily to bore and to thread the screw holes 91 by providing complementary recesses I00 in the upper part of the two main sections 80 and 0|, the recesses I00 being adapted to receive a cover core IOI of dry sand or other refractory material, for forming the top or adjustment end of the tappet 95. Due to the refractory nature of the material composing the cover core IOI the upper end of tappet is not chilled at this point, but is kept in a soft and readily machinable condition. The cover core MI is provided with a central aperture I02 which serves as a gate for filling the mold.

The following analysis of iron aifords an example of a material suitable for producing an all chilled tappet, or one that has a cam engaging surface and'outer periphery of the body chilled but whose top or adjusting screw end may be left soft for machining purposes, and may consist of: Carbon 2.75 to 3.50 per cent, silicon 1.70 to 2.60 per cent, phosphorus 0.20 to 0.30 per cent, manganese 0.40 to 1.10 per cent, sulphur 0.115 per cent, and the balance iron.

A pair of pouring blocks I03 and I04 separable along the parting line 82 constitute a two-piece pouring basin at the top of the mold and are provided with cooperable recesses forming a gate I05 registrable with the opening I02 of cover core IOI so that the two-piece. pouring basis may serve as a sprue and gate for pouring the casting. The mold surfaces of the main mold sections 80 and 8I preferably treated with a refractory facing and sooted in the manner disclosed in Maloche Patents 1,453,593 and 1,492,694. The top of the cover core IN is arranged substantially flush with the top surfaces of the main mold sections 80 and 8|, except for radially disposed vent grooves I05 cut to a depth of approximately 0.015

of an inch for the purpose of providing passages for venting gases from the interior of the mold. The backs of the pouring blocks I03 and I04 are hollowed out as indicated at I01 and I08 and communicate with hollowed out portions I09 and H0 in the backs of the main mold sections 80 and 8| so that cooling air may be circulated about the mold I2 to maintain the desired temperature condition thereof and obtain the desired hardness of the tappet produced.

The main mold section 8| is provided with a passage II2 registrable with a passage II4 through the wall of the separate section 84 so that cooling air may be drawn in from the bottom of the pistonlike separate section 84, around the cooling fin 86, through the passages H4 and H2 to the hollowed out space II 0 in the back of main mold section 8|, and thence through an opening II5 provided adjacent the bottom of the upstanding flange 2I of the partial sector 20 which serves as the stationary carrier for main mold section 8| of mold I2. flange 2I of the stationary mold carrier 20 is provided with an air passage IIG registrable with the hollowed out portion I08 of pouring block I04 and another passage III registrable with the upper portion or the hollowed out chamber IIO of mold section 8I so that cooling air may be drawn into the passages H8 and II! through the hollowed out portions I08 and H0, and thence through the passage II5 to the suction chamber 54 adapted to be exhausted by the suction fan associated with the, conduit 58. It is noted that air will take this course irrespective of whether the mold sections are in open or closed condition. The swingable mold carrier 64 is provided with an upstanding flange I2I corresponding to the flange 2I of the stationary mold carrier 20 and is provided with passages I22 and I23 therethrough. through which passages air may be drawn into the hollowed out portions I01 and I09 of main mold section 80 and thence through the passage 88 and curved conduit 61 of the swingable mold section 64 to the interior of header 60, thence through the interior of the supporting element 50 to the suction chamber 54. It is also noted that air is drawn through this core at all timeswhether the swingable mold carrier 84 is in open or closed position.

While cooling of the mold could be effected by circulating air or other cooling medium in the The upstanding reverse direction from that described, in the case of air it is preferred to circulate it in the described direction since this does not cause excessive amounts of heat to be given off from the molding machine and thus, does not make working conditions disagreeable or even unbearable for attendants of the machine.

Reference may now be had to Figs. 3 and 4,

' which disclose a slightly different form of moldcarry an adjustable support for the pivot 85' of I the swingable mold carrier 84' which is adapted to be secured in adjusted position by means of the bolts I25. The pivot support I24 is also provided with a guide member I26 having a forked upper end I21 adapted to guide and brace, as

well as limit the outward swinging movement of,

' the movable mold carriers 34'.

In the embodiments shown in Figs. 3 and 4 the rollers I3 are adapted to engage the outer periphery of cam contacts I4 for the purpose of maintaining the mold I2 in closed condition,

as before. The rollers I3 are mounted in slide members "I2 arranged for reciprocation in recesses I30 provided in holders I3I and springs II are interposed within suitable bores within the slide members 12' so that the swingable members 34 are maintained in closed condition under spring pressure. The spring pressure for maintaining the swingable mold carriers 63', however, does not exert a lateral thrust upon the shaft 24. A support member I32 includes a bearing I33 within which the shaft 24' is journaled, a pair of radially extending arms I34 and a bridge member I35 upon which the support blocks I3I are mounted by means of bolts I30. The bolts I25 and I36 both pass through en'- larged openings or slots in the header member 30' and bridge member I35 so that the pivot of. the-swingable mold carrier 64 may be adjusted and thus permit proper alignment of the mold sections when the molds are in closed condition and also permit adjustment of the mounting blocks I3I so that the tension of springs I5 may be adjusted to. vary the spring pressure exerted for maintaining the molds in closed condition. A roller carrier I3I is bolted to the outer ends of the arms I34 and pivotally supports a plurality of rollers I38 arranged in a circular series with the axis ofshaft 24 as a center. The rollers I33 bear upon the backs of the flanges 2| of the stationary mold carriers 20 so as to relieve the shaft 24 of lateral pressure exerted by the springs 15 in maintaining the molds I2 in closed condition. Cams I6 and I8 serve to open and to close the molds I2 as before. The construction of the molds I2 and the construction and arrangement of the cooling system for the molds and associated parts is essentially the same as that described relative to the embodiment shown in Figs. 1, 2, and 5.

- Reference may now be had to Figs. 7 and 8, which disclose a modified form of mold adapted to cast an open top type of tappet 95. In this mold construction, the main mold sections and BI are not recessed adjacent the top thereof and no cover core corresponding to the core IOI of Fig. 5 is employed. Pouring blocks I03 and I04 providing a central gate I05 are employed as in the previously described embodiment. The core 93, in the present instance, extends upwardly to a point closely adjacent the bottom surface of the pouring blocks I03 and I04 and is enlarged and axially grooved in its periphery adjacent the upper end thereof sothat plurality of pouring sprues I40, four of such sprues being As many changes could be made in the above described constructions, and many apparently widely diflerent embodiments of this invention could be had without departing from the spirit thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative, and not in a limiting sense,

What is claimed is:

l. A casting machine comprising, in combination, a movable carrier, a mold including two main sections parted vertically, each section having a mold impression cooperable with the impression of the other section for forming a mold cavity and a separate section forming the bottom wall of such mold cavity, a dry sand core within the mold cavity, a cover core, said main mold sections each being provided with a recess for receiving a portion of said cover core, and means for circulating a cooling medium through said carrier and through each of the mold sections, said cover core being constructed of refractory material to shape one end of the casting formed but to prevent chilling of the castingat this point so as to maintain such end of the casting in a soft and machinable condition.

2. A casting machine comprising, in combination, a movable carrier, a mold including two main sections parted vertically, each section having a mold impression cooperable with the impression of the other section for forming a mold cavity and a separate section forming the bottom' wall of such mold cavity, said main mold sections each being provided with a recess adjacent the upper end thereof, a core composed of refractory material arranged within the mold cavity, a cover core of refractory material arranged within the recesses of said main section and adapted to shape one end of the casting formed but to prevent chilling of such end of the casting so as to maintain the same in a soft and machinable condition, and means for circulating a cooling medium through said carrier and through each of said mold sections, said cover core being provided with a central opening therethrough so as to form a gate for filling the mold cavity.

3. A casting machine comprising, in combina-- tion, a movable carrier, a mold including two main sections parted vertically, each section hav ing a mold impression cooperable with the impression of the other section for forming a mold cavity and a separate section forming the bottom wall of such mold cavity, said main mold sections each being provided with a recess adjacent the upper end thereof, a core composed of refractory material arranged within the mold cavity, a cover core of refractory-material arranged within the recesses of said main section and adapted to shape one end of the casting formed but to prevent chilling of such end of the casting so as to maintain the same in a soft and machinable condition, and means for circulating a cooling medium through said carrier and through each of said mold sections, said cover core being provided with a central opening therethrough so as to form a gate for filling the mold cavity, the upper surface of said cover core being arranged flush with the upper surface of said main mold section and said main mold sections each being provided with a groove in the upper surface thereof for venting gases from the mold cavity.

JOSEPH L. DOSTAL.

Images