US2854711A - Shell mold stripping mechanism - Google Patents

Description

Oct. 7, 1958 P. KLAMP sHELL MOLD STRIPPING MECHANISM Filed May 2, 1955 3 Sheets -Sheet 1 in! flrnku ivllli.

INVENTOR. P1904 KAHMP 0d. 7, 1958 P; K M 2,854,711

SHELL MOLD STRIPPING. MECHANISM Filed ma 2, 1955 s sheets-sheet; 3

11v V EN TOR. PA U4 K4 AM P United States SHELL MOLD STRIPPING MECHANISM Paul Klamp, Detroit, Mich., assignor to Mechanical Handling Systems, Inc., Detroit, Mich, a corporation of Michigan Application May 2, 1955, Serial No. 505,291

8 Claims. (Cl. 22-34) This invention relates to improved mechanism for stripping or removing a formed shell mold from a pattern surface which is supported by a pattern carrier.

In accordance with known practice, the pattern carrier is equipped with a stripper plate, supported by the carrier for movement relative thereto, and a number of stripper pins are carried by the stripper plate for movement through holes provided in the pattern. Conventional practice also provides some actuating device for moving the stripper plate in an ejection cycle toward the pattern carrier to project the stripper pins through the holes in the pattern and lift the mold from the pattern surface. This actuating device will be termed a knockout member, and upon movement of the knockout member in the opposite direction to complete the ejection cycle, the stripper plate moves away from the pattern carrier and the stripper pins are withdrawn to a normal position where their ends lie flush with, or slightly below, the surface of the pattern.

The present invention provides a new relationship between these conventional elements, particularly with respect to the relation between the knockout member and the remaining structure. Means are provided, responsive to movement of the knockout member, for positively placing and maintaining the stripper plate in its normal or retracted position and for positively moving the stripper toward and away from the pattern carrier during the ejection cycle.

As the foregoing conventional elements are related in the present invention, the normal or retracted position of the stripper plate relative to the pattern carrier is established and maintained by positioning means which act to prevent movement of the stripper plate toward the pattern carrier. Preferably, guide pins are incorporated as part of the stripper plate assembly, these guide pins being slidable in guide surfaces of the pattern carrier to define the direction of relative movement between pattern carrier and stripper plate. This permits the stripper pins to function solely for the removal of a mold. In the preferred construction, the guide pins also serve to limit movement of the stripper plate away from the pattern carrier so that the guide pins, in combination with the positioning means act to positively define the normal or retracted position of the stripper plate and stripper pins carried thereby.

Release of the positioning means to permit the stripper pins'to be projected through the pattern plate is arranged so as to be in response to movement of the knockout member. As the knockout member approaches the stripper plate, the positioning means are released to permit movement of the stripper plate with the knockout member. Likewise, as the knockout member moves away from the stripper plate the positioning means are reengaged to lock the stripper plate in its normal position. In the preferred construction, the means employed to accomplish this operation include a positioning member pivotally supported by the pattern carrier and mounting a latch surface engageable with a cooperating surface on 2,854,711 Patented Oct. 7, 1958 the stripper plate. A suitable shaped cam track is formed on this pivotally mounted positioning member, this cam track being engageable by a follower carried by the knockout member to thereby produce movement of the positioning member about its pivotal axis between engaged and released positions in response to relative movement between the knockout member and the pattern carrier.

During the ejection cycle the stripper plate is positively secured to the knockout member to insure withdrawal of the stripper plate from ejecting to normal position and the re-engagement of the positioning means which accompanies such withdrawal. This is accomplished by latching means for connecting the stripper plate to the knockout member, these latching means being operable also in response to relative movement between the knockout member and the pattern carrier. As the knockout member approaches the pattern carrier and shipper plate, the latching means are engaged with the stripper plate in response to such movement, and released from the stripper plate in response to movement of the knockout member away from the pattern carrier after the stripper plate has been returned to its normal retracted position and the positioning means engaged for maintaining that position. Preferably, the latching means for so securing the knockout member to the stripper plate comprises latch members pivotally carried by the knockout member and actuatable by engagement with cam surfaces carried by the pattern carrier, this engagement serving to move the latch members into contact with latch surfaces on the stripper plate.

The construction of the invention thus provides for positive location of the stripper plate and stripper pins in a normal position so that no deformation of the mold being formed can result from relative movement between the stripper plate and pattern during any motion imparted to the pattern carrier during the mold forming and curing cycles. The invention also provides for positive movement of the stripper plate toward and away from the pattern carrier during the ejection cycle. For a given size of the component parts, a greater extent of movement of the stripper pins can be obtained by the positive movement of the stripper plate both toward and away from the pattern carrier, than can be obtained by employing springs for returning the stripper pins and plate to normal position. All operations and movements result from relative movement between the knockout member and the pattern carrier, and thus can only take place during the ejection phase of the cycle of a mold forming operation.

Other features and advantages of the invention will be brought out in conjunction with the detailed description to follow of a presently preferred embodiment thereof. This embodiment is illustrated in the accompanying drawings which comprise the following views:

Fig. l, a side elevation of the major components of the invention, comprising a pattern carrier, pattern plate, stripper plate and pins, and a knockout member movable relative to the pattern plate;

Fig. 2, a side elevation of the structure of Fig. 1 taken in the direction of the arrow 2 of Fig. 1;

Fig. 3, an elevation on an enlarged scale taken in the direction of the arrows 33 of Fig. 2, showing one of the positioning members which prevent movement of the stripper plate toward the pattern carrier. In this view, the knockout member is shown displaced from the position of Figs. 1 and 2 and approaching contact with the stripper plate;

Fig. 4, a plan view taken along the lines 44 of Fig. 3;

Fig. 5, a fragmentary plan view taken along the line 5-5 of Fig. 2; and

Fig. 6, a sectional elevation taken along the lines 6-6 of Fig. 2 showing the means for latching the knockout member to the stripper plate in engaged position therewith.

Referring to Figs. 1 and 2, the main component parts there shown include a pattern carrier supporting the pattern plate 11 (Fig. 1), a stripper plate 12 carrying a number of stripper pins 13, and a knockout member or plate 14' which is mounted on the end of the rod 15 of a fluid pressure actuating cylinder assembly 16.

The remaining structure of a specific machine has not been included in the present disclosure because of the obvious fact that the ejection mechanism which forms the subject matter of the present application is not confined in use to a specific machine. For the same reason, full details of the construction of the pattern carrier 10 have not been included herein. However, this pattern carrier is similar in construction, except for features which contribute to the operation of the ejection mechanism of the present invention, to the pattern carrier disclosed in the copending application of Paul Klamp and Leonard 1. Bishop, Serial No. 299,606, filed May 18, 1953, and entitled Turntable Type Machine for Forming Shell Molds.

This pattern carrier 10 consists in a generally rectangular framework in which the pattern plate 11 is removably supported. A boss 18 is provided at each corner of this rectangular framework, each boss being internally drilled and counterbored to provide guide surfaces which slidably receive a guide pin 19, having a headed end 20 engaging the .counterbore, and a threaded end 21 for attachment to the stripper plate 12. Engagement between the headed end 20 of the guide pin 19 and the shoulder 22 at the bottom of the counterbore limits movement of the stripper plate away from the pattern carrier.

. Each stripper pin 13 is dimensioned so that its free end 23 lies flush with, or slightly below, the pattern forming surface 24 of the pattern 11 when the headed end 20 of the guide pin 19 is in engagement with the shoulder 22.

The stripper plate 12 also is a generally rectangular member, conforming roughly to the size and configuration of the pattern carrier 10 and pattern 11. Ordinarily the stripper plate will be provided with rows of holes within any of which a stripper pin 13 can be selectively positioned so that the same stripper plate can be employed in conjunction with a number of different patterns.

When the pattern carrier 10 is in a horizontal position as shown, the stripper plate is suspended therefrom "by the engagement between the head ends 20 of the guide pins 19 and the shoulders 22 within each of the bosses 18.

The means for maintaining the stripper plate 12 in this position except during the ejecting cycle, limit movement of the stripper plate toward the pattern carrier, and comprise a pair of positioning arms 26, each of which is pivotally attached to a portion 27 of the pattern carrier .structure by a pivot pin 28. The arms 26are each free to swing about its pivot pin 28. Each arm carries a latch member 29 (Fig. 3) secured to the arm by a bolt 30 (Fig. 1). Each arm is also provided with a cam track 32 for controlling the position of the arm about its pivot pin 28 in a manner to be soon described.

A pair of latch buttons 34 are secured to the stripper plate 12, each providing a surface 35 adapted to be con tacted by a latch member 29 when the parts are in the position shown in Figs. 1 and 3. Each latch button 34 is mounted in a manner so as to be adjustable relative to the .stripper plate 12.

The knockout member 14 also consists of a rectangular p'late suitably connected to the end of the rod 15 of the actuating cylinder assembly 16. A guide arm 36 is secured to the knockout plate and projects from one side thereof (see Figs. 2 and 5). A guide block 37 is secured to the projecting end of the arm 36, as shown in Fig. 5 and this guide block 37 rides between a pair of vertical angle members 38 which are spaced to form a vertically 4 extending guide slot 39. This keeps the knockout plate 14 and rod 15 from rotating in the actuating cylinder 16 and maintains the knockout plate in proper alignment with the stripper plate and pattern carrier.

A pair of cylindrical cam followers 40 are each mounted on a small pedestal member 41 secured to the knockout plate 14. Each follower 40 projects laterally a slight distance beyond one edge of the knockout plate, as shown in Fig. 2. Also, as shown in Fig. 3, the position of each cam follower 40 is such that it will engage the cam track 32 of one of the positioning arms 26 as the knockout plate is moved verticaly towards the pattern carrier.

In order to produce positive movement of the stripper plate in either direction toward or away from the pattern carrier in response to corresponding movement of the knockout plate, means are provided for latching the stripper plate and knockout plate together. These means include a pair of latch members 44. Each latch member 44 is attached by a pivot pin 45 to a suitable supporting member 46 secured to the underside of the knockout plate 14 as by screws 47 (see Fig. 1). Each latch member 44 is formed with two arms 48 and 49, positioned at right angles to each other. The pivot pin 45 engages a hole formed in the arm 48, which underlies the surface of the knockout plate 14 when the parts are assembled. The other arm 49 projects generally upwardly above the surface of the knockout plate 14. A latch block 5% is mounted on the upper surface of the knockout plate 14 adjacent the arm 49 of each latch member 44. These blocks 50 have two functions; one, to contact the underside of the shipper plate when the knockout plate is moved upwardly; the other, to prevent the arm 49 of each latch member from falling over out of working position onto the top of the knockout plate 14. Such working position is also established by engagement between a tapered surface 51 on the arm 48 of each latch member with the under surface 52 of the knockout plate 14 (see Fig. 6). A V-shaped nose .54 is provided on the arm 49 of each latch member, and complementary surfaces are formed on the edge of the stripper plate 12 at 53. Also mounted on the arm 49 of each latch member is a roller follower 55 which is adapted to contact a cam 56 secured to the structure of a pattern carrier, as shown in Fig. 1.

After a mold has been formed and cured on the pattern 11, the ejection cycle is initiated, fluid pressure being admitted to the actuating cylinder assembly 16 .to produce upward movement of the knockout plate 14, from the position shown in Figs. 1 and 2, toward the pattern carrier 10 which is held, in the conventional manner, in the horizontal position illustrated by means not shown. This movement of the knockout member 14 relative to the pattern carrier results first in the follower members 49 on the knockout plate engaging the cam tracks 32 of the positioning arms 26, and movement of the knockout plate into contact with the stripper Plate is accompanied by pivotal movement of the positioning arms 26, clockwise as these parts are viewed in Figs. 1 and 3, to move the latch member 29 of each arm 26 out of engagement with the latch button 34 of the stripper plate. This pivotal movement of the positioning arms 26 is produced by the first segment 62 of the cam track 32. The remaining segment of the cam track morely acts to hold the positioning arms 26 out of latched position while the stripper plate is moved toward and away from the pattern carrier in the injection cycle.

During the last portion of pivotal movement .of the arms 26, the roller follower 55 on each latch member 44 comes into contact with the tapered surface 57 at the end of each cam member 56. Further upward movement of the knockout plate is accompanied by pivotal movement of each latch member, as the roller follower 55 thereof moves along the surface 57 of the cam members 56, bringing the latch surface 58 on the nose 54 of eachlatch member into engagement with the correspondingly formed surface 59 on the stripper plate. Simultaneously, the latch blocks 58 on the knockout plate are coming into contact with the under surface of the stripper plate. The parts are held in latched engagement during further upward movement of the knockout member, as the roller followers 55 ride along the vertical straight surface 60 of each cam member 56.

After the knockout plate and stripper plate have been moved toward the pattern carrier to the extent desired for proper ejection of the mold from the pattern, the direction of movement of the knockout plate is reversed. During the first portion of this return movement, the stripper plate 12 and its stripper pins 13 are positively withdrawn from the pattern carrier by the latched engagement between the stripper plate and knockout plate. The parts are dimensioned so that as the head ends 20 of the guide pins 19 come into contact with the shoulders 22 in the guide bores, the roller follower 55 of each latch member reaches the tapered end surface 57 of its cam 56. Contact between the head ends of the pins 19 and the shoulders 22 arrest further withdrawing movement of the stripper plate and stripper pins. The tapered surfaces 58 and 59 of the latch members 44 and stripper plate 12, respectively, produce a pivotal releasing movement of the latch members in response to further withdrawing motion of the knockout plate. Simultaneously, the followers 40 have reached the actuating segment 62 of the cam track 32 of each positioning arm 26, producing a pivotal movement thereof to bring the latch member 29 back into engagement with the latch button 34. Thus, as knockout plate separates from the stripper plate the latter is locked in position relative to the pattern carrier.

From the foregoing it can be seen that all movements of the stripper plate and associated latching devices occur in response to movement of the knockout plate. This means that no movement of the stripper plate can take place except during the knockout cycle of operation of the mold forming machine. Consequently, no damage to a mold being formed can result by displacement between the stripper plate and pattern carrier.

Likewise, the arrangement of movement in response to knockout plate movement is accomplished with relatively simple structure that is completely positive in action.

Changes and modifications to the specific structure shown and described are to be considered a practice of the present invention if embraced within the scope thereof as defined in the following claims.

I claim:

1. Mechanism for stripping a shell mold from a pattern, supported by a pattern carrier, by movement of a stripper plate and stripper pins from a normal position where the stripper pins do not project above the pattern surface to an ejecting position where the stripper pins are projected above the pattern surface through holes therein, characterized by means suspending said stripper plate from said pattern carrier for movement relative thereto between said normal and ejecting positions, releasable positioning means interposed between said pattern carrier and stripper plate for normally preventing movement of said stripper plate toward ejecting position, a knockout member and means for moving said knockout member toward and away from said pattern carrier in an ejection cycle, and means for releasing said positioning means in response to movement of said knockout member toward said pattern carrier.

2. Mold stripping mechanism as set forth in claim 1 further characterized by the provision of latch means for securing said knockout member to said stripper plate during movement of said stripper plate toward and away from said pattern carrier. I

3. Mold stripping mechanism as set forth in claim 2 wherein said latch means comprise a latch member pivotally supported by said knockout member, a latch surface on said stripper plate adapted to be engaged by said latch member, and a latching cam carried by said pattern carrier for producing engagement between said latch member and latch surface in response to relative movement of said knockout carrier toward said pattern carrier and for releasing said latch member from said latch surface in response to movement of said knockout member away from said carrier.

4. Mold stripping mechanism as set forth in claim 1 wherein said positioning means comprise a positioning member pivotally secured to said carrier, latch surfaces provided on said member and on said stripper plate, said releasing means producing pivotal movement of said positioning member from a latched to an unlatched position of said latch surfaces in response to relative movement between said knockout member and said carrier.

5. Mold stripping mechanism as set forth in claim 4 wherein said releasing means for producing pivotal movement of said positioning member include a cam surface formed thereon and a cam follower carried by said knockout member.

6. Mechanism for stripping a shell mold from a pattern, supported by a pattern carrier, by movement of a stripper plate and stripper pins from a normal position where the stripper pins do not project above the pattern surface to an ejecting position where the stripper pins are projected above the pattern surface through holes therein, characterized by means suspending said stripper plate from said pattern carrier for movement relative thereto between said normal and ejecting positions, said suspending means acting to define said normal position, releasable positioning means interposed between said pattern carrier and said stripper plate for normally preventing movement of said stripper plate towards ejecting position, a knockout member and means for moving said knockout member between normal and ejecting positions in an ejecting cycle, means for releasing said positioning means in response to movement of said knockout member toward said stripper plate into contact therewith, and means for latching said knockout member to said stripper plate in contact therewith during movement of said stripper plate from normal to ejecting position and return.

7. In mechanism for stripping a shell mold from a pattern which includes a pattern carrier, a reciprocable knockout member and a stripper plate member movable to and from the pattern in a mold ejection cycle when contacted by the knockout member, the combination of a latch carried by one of said members and normally biased to unlatched position, a latch surface provided on the other of said members for engagement by said latch, and means for engaging said latch with said latch surface in response to movement of said knockout member toward said pattern carrier during the mold ejection cycle of movement of said stripper plate, said latch engaging means comprising a fixed latching cam positioned to be contacted by said latch as the knockout member contacts the stripper plate, said cam having an initially contacted surface for causing movement of said latch to engaged position and a continuing surface for holding said latch in engagement during the mold ejection cycle of movement.

8. A mold stripping mechanism according to claim 7 wherein said latch cam is fixedly supported by said pattern carrier.

References Cited in the file of this patent UNITED STATES PATENTS 2,669,759 Valyi Feb. 23, 1954 2,691,195 Daugindas Oct. 12, 1954

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