US3774815A

US3774815A - Mechanical ladle mechanism having four-bar configuration

Info

Publication number: US3774815A
Application number: US00302350A
Authority: US
Inventors: J Mccarthy
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-10-30
Filing date: 1972-10-30
Publication date: 1973-11-27
Anticipated expiration: 1990-11-27

Abstract

A mechanical ladle mechanism having a four-bar configuration. The four-bar ladle mechanism has a first bar having a first end and a second end opposite the first end, a second bar in spaced apart relationship to the first bar also having a first end and a second end opposite its first end, a third fixed bar having a first end and a second end opposite its first end, and a fourth bar in spaced apart relationship to the fixed third bar also having a first end and a second end opposite its first end. The first end of the first bar is pivotally attached to the second end of the third bar, the first end of the second bar is pivotally attached to the first end of the third bar, the first end of the fourth bar is pivotally attached to the second end of the second bar, and the second end of the fourth bar is pivotally attached to the second end of the first bar. A ladle is removably attached to the fourth bar, the longitudinal axis of the ladle being substantially parallel to the longitudinal axis of the fourth bar. A hydraulic cylinder or rack and pinion may be operatively associated with the first bar to cause it to rotate about the pivotal mounting at its first end. The second bar and fourth bar with the ladle attached follow the rotational motion of the first or driver bar.

Description

United States Patent [191 McCarthy [111 3,774,815 Nov. 27, 1973 MECHANICAL LADLE MECHANISM HAVING FOUR-BAR CONFIGURATION [76] Inventor: John McCarthy, 4133 Scottdale Rd., St. Joseph, Mich. 49085 22 Filed: Oct.30, 1972 21 Appl.No.:302,350

Primary Examiner-Robert B. Reeves Assistant Examiner-David A. Scherbel Att0rneylrving M. Weiner et al.

[57] ABSTRACT A mechanical ladle mechanism having a four-bar configuration. The four-bar ladle mechanism has a first bar having a first end and a second end opposite the first end, a second bar in spaced apart relationship to the first bar also having a first end and a second end opposite its first end, a third fixed bar having a first end and a second end opposite its first end, and a fourth bar in spaced apart relationship to the fixed third bar also having a first end and a second end opposite its first end. The first end of the first bar is pivotally attached to the second end of the third bar,'the first end of the second bar is pivotally attached to the first end of the third bar, the first end of the fourth bar is pivotally attached to the second end of the second bar, and the second end of the fourth bar is pivotally attached to the second end of the first bar. A ladle is removably attached to the fourth bar, the longitudinal axis of the ladle being substantially parallel to the longitudinal axis of the fourth bar. A hydraulic cylinder or rack and pinion may be operatively associated with the first bar to cause it to rotate about the pivotal mounting at its first end. The second bar and fourth bar with the ladle attached follow the rotational motion of the first or driver bar.

12 Claims, 5 Drawing Figures MECHANICAL LADLE MECHANISM HAVING F OUR-BAR CONFIGURATION BACKGROUND OF THE INVENTION 1. Field of thelnvention The invention relates to a four-bar mechanism having one'bar fixed, two bars which rotate about opposite ends of the fixed bar and impart a general plane motion to a fourth bar and a ladle attached thereto. In particular, the invention pertains to a four-bar mechanical ladle mechanism which lifts a ladle from a furnace in a substantially vertical position, transports the ladle to a casting station, and causes the ladle to pour the mo]- ten metal into a mold. Although the four-bar mechanism is described with reference to a molten metal pouring device, the mechanism may be incorporated with a multiple of machines where it is desired to transport items from one fixed point to another fixed point.

2. Description of the Prior Art A number of prior art devices for conveying a molten metal from a furnace to a pouring station utilize a ladle conveying mechanism which imparts a rotational motion to the ladle as it is lifted from the furnace. With these'prior art devices, as the ladle is lifted from the furnace containing a molten metal, the ladle is tilted or tipped due to the rotational motion imparted to it by the conveying mechanism. As the level of the molten metal in the furnace varies due to prior extractions of the molten metal from the furnace, this tipping motion of the ladle makes it very difficult, if not impossible, to obtain uniform shots, or amounts of molten metal in the ladle between successive ladle filling events. Some prior art devices also utilize a four-bar mechanism, but do not restrain any of the bars from moving and, thus require at least two hydraulic cylinders or other driving means to actuate the mechanism to transport the ladle from a fill position at the furnace to a pour position at a die. or mold station.

The four-bar mechanical ladle mechanism of the present invention is simple, less expensive than the prior art mechanisms, and allows for greater uniformity between successive'shots of molten metal in the ladle.

SUMMARY OF THE INVENTION The invention provides a mechanical ladle mechanism having a four-bar frame structure having a first link or bar with a first end and a second endopposite the first end; a second link or bar having a first end and a second end opposite its first end; a third fixed link or bar having a first end, the first endof the second link being pivotally attached thereto, and a second end opposite the first end, the first end of the first link being pivotally attached thereto; and a fourth link having'a first end pivotally attached to the second end of the second link and a second end opposite the first end pivotally attached to the second end of the first link. A ladle adapted to contain and pour molten metal is removably affixed to the fourth link. The distance between the pivotal mounting points on the second link is less than the distance between the pivotal mounting points on the first link to keep the fourth link, and ladle in a substantially vertical position as the first and second links pivot about their respective pivotal mounting points during the initial portion of movement of the mechanism as it lifts the ladle from a furnace which contains the molten metal. Driving means such as a hydraulic cylinder and clevis mounting, or rack and pinion arrangement is operatively associated with the first link to cause the first link to rotate about its point of pivotal attachment to the third fixed link. Due to the pivotal interconnection of the first, second and fourth links, the second and fourth links are driven by the first link and, therefore, generally follow the rotational motion of the first link.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of the preferred embodiment of the four-bar mechanical ladle mechanism.

FIG. 2 is a top view of the four-bar mechanical ladle mechanism taken along line 2-2 in FIG. 1.

FIG. 3 is a fragmentary side view ofa portion of the mechanism shown in FIG. 1 showing the hydraulic cylinder and clevis driving means.

FIG. 4 is a fragmentary side view of a portion of the mechanism as shown in FIG. 1 showing the rank and pinion driving means.

FIG. 5 shows a side view of another embodiment of the mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIG. 1, the mechanical ladle mechanisrn, generally denoted as 1, includes a first link or bar 3 having a first end 5 and a second end 7 opposite the first end, and a second link 9 having a first end 11 and a second end 13 opposite its first end. A third fixed link 15 has first end 17 and a second end 19 opposite the first end 17. The first end 11 of the second link 9 1 is pivotally attached to the first end 17 of the third link 15, and the first end 5 of the first link 3 is pivotally attached to the second end 19 of the third link 15. A fourth link 21 has a first end 23 pivotallyattached to the second end 13 of the second link 9 and a second end 25 opposite the first end 23 also pivotally attached to the second end 7 of the first link.3.

.A ladle 27, adapted to contain and pour a molten metal is removably attached to the fourthlink 21- by attachment means 29.

With reference to FIGS. 3 and 4, driving means 31 is I operatively affixed to the first link 3, the first link 3 therefore constituting a driving link, and the second and fourth links being driven by the first link constitute driven links.

Again with reference to FIG-l, the third link l5 is fixed, i.e., has zero degrees of freedom. The first link 3 is pivotally attached near its first end 5 to the third link 15 near its second end 19 for rotational movement about the pivotal attachment. The second link 9 is pivotally attached near its first end 11 to the third link 15 near its first end 17 for rotational movement about the pivotal attachment. The fourth link 21 is pivotally attached near its first end 23 to the second link 9 near its second end 13, and pivotally attached near its second end 25 to the first link 3 near its second end 25. The pivotal attachments of the fourth link 21 at its opposite ends allows the fourth link to move in a general plane motion, i.e., a combination of translation and rotation in the same plane of rotation of the first link 3 and second link 9 or in a plane of rotation parallel thereto.

Attachment means 29, such as a plurality of pins 33 and notches 35, 37 removably hold the ladle 27 in position adjacent the fourth link 21.

The driving means 31 may consist of any of a number of devices well known to those skilled in the art. With reference to FIG. 3, the driving means 31 may consist of a clevis 39 affixed at one end to the first end 5 of the first link 3, and a double acting hydraulic cylinder and piston 41 operatively affixed to the clevis at an end thereof opposite that end affixed to the first link 3. As the hydraulic cylinder and piston 41 are actuated to cause its associated rod to contract into the cylinder, or move to the right as viewed in FIG. 3, the first link will be forced to rotate in a counter clockwise direction about its point of pivotal attachment to the third link 15, thus causing the driven arm or second link 9 to also rotate in a counter clockwise direction, as viewed in FIG. 1, about its point of pivotal attachment to the third link 15, and causing the fourth link 21 to move in a counter clockwise direction as it pivots about its points of pivotal attachment, and translate in the plane of rotation of the first link 3 and second link 9. As the rod of the hydraulic cylinder and piston 41 extends, the

first link 3, second link 9, and fourth link 21 are caused to rotate in a clockwise direction as viewed in FIG. 1.

With reference to FIG. 4, the driving means 31 may alternatively consist of a pinion gear 40 operatively affixed to the first end 5 of the first link 3, and a rack 42 operatively associated with the pinion gear 40. As the rack 42 translates to the right, the first link 3 is driven in a counter clockwise direction and the second link 9 and fourth link 21 follow in a counter clockwise direction as they did in the embodiment described above when the piston rod of the hydraulic cylinder and piston 41 contracted. As the rack 42 translates to the left, the first link 3, second link 9 and fourth link 21 move in a clockwise direction as when the rod of the hydraulic cylinder and piston 41 extended.

Both of the embodiments, one embodying a clevis 39 and hydraulic cylinder 41, and the other using a rack 42 and pinion 40 provide a single driving center at the pivotal attachment of the first link 3 to thethird link by which the mechanism is put into motion.

It is to be noted that in the preferred embodiment illustrated in FIG. 1, the distance between the pivotal mounting points at the first and second ends 5, 7 of the first link 3 is greater than the distance between the pivotal mounting points at the first and second ends 11, 13 of the second link 9, and that the pivotal mounting point of the first link 3 to the fourth link 21 and the pivotal mounting point of the third link 9 to the fourth link 21 are on a common substantially vertical center-line 24.

It has been found that a relative differential of approximately one inch in the distances between the pivotal mounting points of the first link 3 and pivotal mounting points of the third link 9 allows the mechanism to perform satisfactorily and results in a compact mechanism.

In the fill position, shown in solid lines in FIG. 1, a portion of the ladle 27 is positioned below a top surface 43 of a molten metal bath 45 in a conventional furnace 47. In this position, the ladle 27 receives a measured amount of molten metal. It should be mentioned at this point that a conventional ladle of most any configuration may be employed. As the first link 3 rotates in a counter clockwise direction and the second link 9 and fourth link 21 follow in the counter clockwise movement, as viewed in FIG. 1, the centerline 24 common to the pivotal mounting of the first link 3 to the fourth link 21 and pivotal mounting of the third link 9 to the fourth link 21 remains substantially perpendicular to the surface 43 of the molten metal bath 45 during the first phase of its motion which causes the ladle 27 to exit from the molten metal bath 45 in a substantially vertical position. This is due to'the geometry of the mechanism 1, in particular the relationship of the distances between the pivotal mounting points of the first link 3 and the pivotal mounting points of the second link 9. The attribute of the mechanism 1 to lift the ladle 27 from the molten bath 45 in a substantially vertical position is extremely important from a practical sense in that it ensures that the ladle 27 will receive a same measured amount of molten metal during a series of filling events, even as the surface 43 of the molten metal bath 45 varies due to the fact that previous filling events have depleted the amount of molten metal in the furnace 47. That is to say, the ladle 27 is repeatedly filled with the same amount of molten metal in repeated filling events without the necessity of continuously recharging the furnace 47 with more molten metal to maintain the surface 43 at a consmnt level.

It is seen in the broken lines of FIG. 1 that as the links 3, 9 and 21 rotate counter clockwise, that through the first phase of rotation the common centerline 24 remains substantially vertical, and the ladle 27 remains substantially perpendicular to the top surface 43 of the molten metal bath 45. As the links 3, 9 and 21 continue to move in a counter clockwise direction, the common centerline 24 on the fourth link 21 deviates substantially from the vertical and passes through the horizontal to a point where it is at an acute angle to the horizontal. Because the ladle 27 is afi'nred to the fourth link 21, it also deviates from its perpendicular position, and passes through the horizontal to a point where it also is at an acute angle to the horizontal as the links 3, 9 and 21 move counter clockwise. As the ladle 27 passes through the horizontal it arrives at a pour position which results in molten metal contained therein being poured into a casting means 49, such as a die or mold.

It can be seen in FIG. 1 that as the links 3 and 9 rotate to the'pour position, the first link 3 must cross the third link 9. That is, the first link 3 must pass over the pivotal mounting point of the first end 11 of the second link 9 to the first end 17 of the third link 15 to a position on the opposite side of the third link 15 than that side of the third link 15 it was on when the mechanism was in the fill position. To accomplish this without interference between the first link 3 and second link 9 or the first link 3 and the first end 17 of the third link 15, the first and second links are transversely separated or off-set from each other, i.e., they are in different vertical planes as can be'best seen in FIG. 2'. The amount of off-set may be of any convenient distance, so long as a clearance is maintained between the link 3 and link 9, and the link 3 and first end of link 15.

In the preferred embodiment, shown best in FIG. 1, of the four-bar mechanical ladle mechanism 1, the first link 3 is generally U-shaped or has a U-shaped portion to allow the positioning of the ladle 27 deep inside a furnace holding tank by providing a clearance area below the first link into which a side of the furnace or holding'tank can project. In addition, this generally U- shaped first link provides a clearance below the first link for any accessory equipment which may be located adjacent the furnace or holding tank and which may, otherwise, interfere with a ladle mechanism.

In a second embodiment, illustrated in FIG. 6, the first link 3' is at an angle to the second link 9' when viewed in profile.

In the embodiment of FIG. 1, the first link 3 rotates through an angle of approximately 120 from the ladle fill position to the ladle pour position, while the first link 3 of the embodiment of FIG. 6 rotates through an angle of approximately 90 from the ladle fill position to the ladle pour position.

In yet another alternative configuration, not illustrated, the four-bar mechanism 1 could assume a configuration generally laterally quadrilateral in profile when in the ladle fill. position. More particularly, the first link 3 is substantially parallel to the second link 9, the links, of the mechanism 1 thus forming a substantially trapezoidal profile.

Further, in another altemative'configuration, not illustrated, the first and second links may be bent midway between their ends both in generally the same direction such that when viewed in aplan view the second end 7 of the first bar 3 is in a different vertical plane than the first end 5, and likewise, the second end 13 of the second bar 9 is in a different vertical plane than the first end 1 1. This configuration allows a greater flexibility of mounting of the mechanical ladle mechanism, particularly in applications were there is a limited amount of space to mount the mechanism, for example,

where the space available for the mechanism is smaller than the longitudinal lengths of the first and second bars as they are illustrated in FIG. 2.

There are a number of methods which may be employed to removably attach the ladle 27 to the fourth link 21; the preferred way is that illustrated in FIG. 1. In this embodiment, two generally horizontal spaced apart parallel rods or pins 33 are affixed to the fourth link 21 perpendicularly to the longitudinal axis of the first link 3 and/or second link 9. A flange 34 is affixed to the ladle 27 to project radially therefrom. The flange has first and second notches 35, 37, respectively, each having a rounded end opposite its open end, each notch being adapted to receive one of the rods 33. The first notch 35 is oriented such that its open end is toward a top edge of the flange 34, i.e., a centerline of the notch common to its rounded end and open end is perpendicular to the similar center-line of the first notch 34. This configuration holds the ladle 27 substantially parallel to the fourth link 21, and allows the ladle to faithfullyfollow the motion of the fourth link 21. This copnfiguration also allows easy removal of the ladle 27 from the fourth link 21 by rotating the ladle 27 counter clockwise, as viewed in FIG. 1, about the first notch 35 until the second notch 37 is free from its associated rod 33,

and then pulling the ladle in the direction of its longitudinal axis until the first notch 35 is free from its associated rod 33.

The foregoing detailed description is given primarily for cleamess of understanding and no unnecessary limitations should be understood therefrom, for some modifications will be obvious to those skilled in the art.

I claim:

1. A mechanical ladle mechanism for transporting and pouring a molten metal from a furnace to a casting means, comprising:

a first link having a first end and a second end opposite said first end;

a second link having a first end and a second end posite said first end;

a third fixed link having a first end and a second end opposite saidfirst end of said second link being pivotally attached to said first end of said third link, and said first end of said first link being pivotally attached to said second end of said third link;

a fourth link having a first end pivotally attached to said second end of said second link, and a second end opposite said first end pivotally attached to said second end of said first link;

a ladle adapted to contain and pour said molten metal affixed to said fourth link;

the distance between said first end and said second end of said first link being greater than the distance between said first end and said second end of said second link; I

driving means operatively associated with said mechanism to cause said first link and said second link to rotate about their respective pivotal mounting on said third link, and said fourth link to move in a general plane motion in a plane of rotation similar to the plane of rotation of said first link and said second link.

2. A mechanical ladle mechanism as defined in claim 1, wherein at least a portion of said first link and at least a portion of said second link are included in different vertical parallel planes.

3. A mechanical ladle mechanism as defined in claim 2, wherein at least a portion of said first link is generally U-shaped to produce a clearance area.

4. A mechanical ladle mechanism as defined in claim 3, wherein said ladle is positioned on said fourth link to be generally perpendicular to a surface of said molten metal in said furnace when said mechanism is in a fill position.

5. A mechanical ladle mechanism as defined in claim 4, wherein said driving means is operatively associated with said first link.

6. A mechanical ladle mechanism as defined in claim 2, wherein said first, second, third and fourth links form a structure generally laterally quadrilateral in profile when said mechanism is in a fill position.

7. A mechanical ladle mechanism as defined in claim 6, wherein said'ladle is positioned on said fourth link to be generally perpendicular to a surface of said molten metal in said furnace when said mechanism is in a fill position.

8. A mechanical ladle mechanism as defined in claim 7, wherein said driving means is operatively associated with one of said first, second, third or forth links.

, 9. A mechanical ladle mechanism as defined in claim 8, wherein a common centerline between said pivotal mounting point of said second link to said fourth link and said pivotal mounting point of said first link to said fourth link is generally perpendicular to a surface of said molten metal in said furnace.

10. A mechanical ladle mechanism as defined in claim 9, wherein said generally laterally quadrilateral profile is substantially trapezoidal.

11. A mechanical ladle mechanism as defined in claim 10, wherein said first link is generally parallel to said second link.

12. A mechanical ladle mechanism as defined in claim 11, wherein said ladle is positioned on said fourth link such that a generally longitudinal centerline of said ladle is substantially parallel to said common centerline between pivotal mounting points on said fourth link.

* k l I! l UNITED STATES IYATENT OFFICE CERTIFICATE OF CORRECTION Dated' November 27, 1973 Patent No. 3 774', 815

Inventor(s) John McCar thy It is cettified that error appesrs in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

O In the title page column I, line 5 below inventor information insert:

{73] ASSIGNEE: MPH Industries, Inc. Riverside, Mich a corporation of Michigan Signed and sealed this 6th day oft August 197A.

' (SEAL) Attest:

MCCOY M. GIBSON, JR. C. MARSHALL DANN Commissioner of Patents Attesting Officer

Claims

1. A mechanical ladle mechanism for transporting and pouring a molten metal from a furnace to a casting means, comprising: a first link having a first end and a second end opposite said first end; a second link having a first end and a second end opposite said first end; a third fixed link having a first end and a second end opposite said first end of said second link being pivotally attached to said first end of said third link, and said first end of said first link being pivotally attached to said second end of said third link; a fourth link having a first end pivotally attached to said second end of said second link, and a second end opposite said first end pivotally attached to said second end of said first link; a ladle adapted to contain and pour said molten metal affixed to said fourth link; the distance between said first end and said second end of said first link being greater than the Distance between said first end and said second end of said second link; driving means operatively associated with said mechanism to cause said first link and said second link to rotate about their respective pivotal mounting on said third link, and said fourth link to move in a general plane motion in a plane of rotation similar to the plane of rotation of said first link and said second link.

7. A mechanical ladle mechanism as defined in claim 6, wherein said ladle is positioned on said fourth link to be generally perpendicular to a surface of said molten metal in said furnace when said mechanism is in a fill position.

9. A mechanical ladle mechanism as defined in claim 8, wherein a common centerline between said pivotal mounting point of said second link to said fourth link and said pivotal mounting point of said first link to said fourth link is generally perpendicular to a surface of said molten metal in said furnace.