DIE-CHANGING MECHANISM FOR AN EXTRUSION PRESS
United States Patent 3599467
The die is held in axial alignment with the billet container during extrusion by a reciprocable die slide and a cooperating locking member. The die slide has a U-shaped pocket in one end for releasably holding the die carrier and its supporting bolster. The locking member is adapted to engage in a peripheral groove in the die carrier. To change a die, the locking member is disengaged and the die slide is moved laterally to a position where a pivotable receptacle can engage the carrier. The receptacle is then pivoted to lift the carrier out of the pocket in the slide, and swing it to a position where the carrier and die can readily be lifted out of the receptacle. For greater convenience two receptacles may be provided that are movable axially along their common pivotal axis so that a new die can be loaded in one receptacle while the previously used die is being removed from the other receptacle.
US Patent References:
Horizontal extrusion press
Vogel - January 1964 - 3116833
Extrusion press
Walker - May 1968 - 3385090
Extrusion presses
Linnerz - July 1968 - 3391564
DEVICES FOR PREPARING DIES AND CONVEYING THEM TO THE DIE CARRIER IN EXTRUSION PRESSES
Groos - September 1969 - 3465565
Extrusion presses
Groos - March 1965 - 3175384
Horizontal extrusion press
Vogel - January 1964 - 3116833
Extrusion press
Walker - May 1968 - 3385090
Extrusion presses
Linnerz - July 1968 - 3391564
DEVICES FOR PREPARING DIES AND CONVEYING THEM TO THE DIE CARRIER IN EXTRUSION PRESSES
Groos - September 1969 - 3465565
Extrusion presses
Groos - March 1965 - 3175384
Application Number:
04/762032
Publication Date:
08/17/1971
Filing Date:
09/24/1968
View Patent Images:
Export Citation:
Assignee:
Farrel Corporation (Rochester, NY)
Primary Class:
International Classes:
B21C23/21; B21C23/00; B21C23/00
Field of Search:
72/263
US Patent References:
Primary Examiner:
Lanham, Charles W.
Assistant Examiner:
Rogers R. M.
Claims:
Having thus described my invention, what I claim is
1. A die-changing mechanism for an extrusion press which is provided with a container housing, comprising
2. A die-changing mechanism for an extrusion press, comprising
3. A die-changing mechanism as defined in claim 2, wherein said means for securing the carrier in the pocket of said slide comprises a locking member relative to said slide and in parallelism thereto between a locking position, in which it engages said carrier to secure the carrier releasably in the pocket of said slide, and a released position in which it is disengaged from the carrier to permit movement of the carrier selectively out of said slide pocket
4. A die-changing mechanism as defined in claim 3, wherein
5. A die-changing mechanism as defined in claim 4, including
1. A die-changing mechanism for an extrusion press which is provided with a container housing, comprising
2. A die-changing mechanism for an extrusion press, comprising
3. A die-changing mechanism as defined in claim 2, wherein said means for securing the carrier in the pocket of said slide comprises a locking member relative to said slide and in parallelism thereto between a locking position, in which it engages said carrier to secure the carrier releasably in the pocket of said slide, and a released position in which it is disengaged from the carrier to permit movement of the carrier selectively out of said slide pocket
4. A die-changing mechanism as defined in claim 3, wherein
5. A die-changing mechanism as defined in claim 4, including
Description:
This invention relates to extrusion presses, and more particularly to a mechanism for changing dies in an extrusion press.
During extrusion, the die is held in axial alignment with the billet container. In known presses to change the die, a slide, on which the die carrier is mounted, is actuated to move the die carrier from center position to a position at one side of the press where the die can be more conveniently removed from the press and replaced.
The primary object of this invention is to provide means for moving a die carrier to a more convenient location for removal of a die and substitution of another die.
Another object of the invention is to provide apparatus of the nature which will minimize handling during die changing.
Another object of this invention is to provide a novel die-changing mechanism of the type described, which may readily be automated to automatically remove one die from a press and replace it with another.
A more specific object of this invention is to provide a novel die changing mechanism capable of handling a plurality of dies, so that one die can be removed from a die slide and immediately replaced by another.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.
In the drawings:
FIG. 1 is a fragmentary plan view of an extrusion press made in accordance with one embodiment of this invention, parts thereof being cut away and shown in section; and
FIG. 2 is a fragmentary sectional view taken along the line 2-2 in FIG. 1 and looking in the direction of the arrows.
In the drawings 22 denotes the conventional end platen, 23 designates the conventional main tie bolts (FIG. 2) and 24 denotes the usual container housing of an extrusion press. Housing 24 is mounted in usual manner on rods 25 (FIG. 2) for reciprocable movement parallel to the tie bolts 23.
20 DENOTES GENERALLY A DIE SLIDE ASSEMBLY FOR THE PRESS. This assembly 20 comprises a die slide 30, which is mounted on guide brackets 32 and 34 for rectilinear sliding movement on the face of the platen 22 transversely of the axis of the container in housing 24. Slide 30 is reciprocated by a piston 40 which is connected to the slide 30 by piston rod 42 and coupling 43. Piston 40 reciprocates in a cylinder 36, which is mounted by bracket 38 on platen 22.
Removably seated coaxially in an arcuate or U-shaped pocket 45 in slide 30 are a cylindrical die carrier 46, and the supporting bolster 48 (FIG. 1). The forward end of the carrier (lower end in FIG. 1) projects axially beyond the corresponding end of the pocket. Die carrier 46 has an axial bore 47 in which a die (not illustrated) is adapted to be secured in the usual manner. Pocket 45 faces diagonally upwardly and toward the left in FIG. 2, so that the carrier 46 and the associated bolster 48 may be inserted into, or withdrawn from, the pocket radially as indicated by the arrows 49 in FIG. 2.
Mounted for sliding movement on slide 30 radially of carrier 46 is a yoke-shaped locking collar or gate 52, which has a tongue 53 that engages in a groove 56 formed in the periphery of die carrier 46 coaxially thereof, thereby to secure the die carrier against axial movement in pocket 45.
Locking member 52 is secured to a pair of spaced, parallel operating rods 58 and 59, which extend slidably through die slide 30 and are secured to a crossplate 64. Crossplate 64 is fastened to the piston rod 62 of a piston (not illustrated) which reciprocates in a cylinder 60 that is mounted to project laterally from slide 30.
Fixed at one end in the platen 22 at the side thereof remote from cylinder 36, and projecting from the face of the platen parallel to the main tie bolts 23 and to the axis of the container housing 24, is a shaft 66. Mounted beneath and parallel to shaft 66 is a second shaft 67 (FIG. 2), opposite ends of which are fixed in spaced brackets 68 that are welded to an I-beam 69 that extends along the bottom of the press at one side thereof.
Shafts 66 and 67 support a die changing mechanism 70, comprising a pair of spaced, parallel arms 72 and 73, which are pivotally mounted on a sleeve or bushing 74 (FIG. 2) that is mounted for axial sliding movement on shaft 66. At their free, or right-hand ends as illustrated in the drawings, the arms 72 and 73 carry identical, generally arcuate or U-shaped shoes or receptacles 76 and 77, respectively, which are integral with the respective arm 72, 73. Medially of its ends each shoe 76, 77 is formed with an arcuate groove 78, disposed between arcuate flanges 79 and 80. In each shoe the flange 79 projects in a radial direction slightly beyond the adjacent flange 80, and has a chamfered lower end 79', which registers with a like end 80' on flange 80.
Remote from the shoes 76 and 77, arms 72 and 73 have projections 82 and 83, respectively, which are pivotally connected by a shaft 81 and a link 85 to the upper end of a piston rod 86. The piston (not illustrated), that actuates rod 86, is housed in a cylinder 87, which is pivotally connected at its lower end by pin 88 to a collar 89 that is carried by a bushing or sleeve 90, that is axially slidable on shaft 67.
Secured at their lower ends to opposite ends of the sleeve 90, and adjacent their upper ends to opposite ends of the sleeve 74, are two, spaced, parallel plates or webs 92, 93. Adjustably secured in a crossbar 95, which extends between the upper ends of the plates 92 and 93 are two, adjustable stops 96, the lower ends of which overlie the projections 82 and 83 on the arms 72 and 73, respectively. The bolts 96 can be adjusted to limit pivotal movement of the arms 72 and 73 clockwise (FIG. 2) about the axis of shaft 66.
Arms 72 and 73 are separated by a spacer 97; and end plates 92 and 93 are separated from arms 72 or 73, respectively, by further spacers 98. The spacers are mounted on sleeve 74. Beneath shaft 66 the end plates 92 and 93 are further secured in spaced relation to one another by a reinforcing plate 99 (FIG. 2), opposite sides of which are bolted or otherwise secured to the confronting faces of end plates 92 and 93.
Secured to the side of platen 22 to the rear of the die-changing mechanism 70 is a cylinder 104 (FIG. 1). The rod 105 (FIG. 2) of a piston (not shown), which reciprocates in this cylinder, is secured at its outer end by a plate 106 (FIG. 2) to the rear face of plate 92 approximately medially of the upper and lower ends thereof. Cylinder 104 is mounted so that piston rod 105 reciprocates parallel to shafts 66 and 67, thereby to impart reciprocable motion to the mechanism 70 axially of these shafts.
Normally die slide 30 is positioned, as illustrated in the drawings, so that the die carrier 46 registers axially with the main ram of the press; and the locking member 52 is engaged in groove 56 in carrier 46 to hold the carrier against axial movement relative to the bolster assembly 48. Also, the piston rod 86 (FIG. 2) normally is in its retracted position, so that arms 72 and 73 are held in retracted positions. The piston rod 105, too, is in its retracted position, so that the die-changing mechanism 70 is located on the shafts 66 and 67 immediately adjacent to platen 22, that is, in its solid line position in FIG. 1. In this position flange 80 of shoe 77 will register axially with groove 84 in carrier 46.
When it is desired to change dies piston rod 86 is actuated to cause arms 72 and 73 to pivot (clockwise in FIG. 2) downwardly from their inoperative positions (indicated in dash lines in FIG. 2) to their operative positions (shown in solid lines). The piston in cylinder 60 is now actuated to move crossmember 64 towards the right in FIG. 1, thereby to retract the locking member 52, and to disengage the member 52 from the die carrier 46. Simultaneously piston 40 is actuated to advance the die slide 30 toward the left in FIGS. 1 and 2 far enough to cause the projecting end of carrier 46 to be pushed over the chamfered ends 79' and 80' of the shoe 77 until the flange 110 on the carrier 46 drops into the registering recess 78 in the shoe 77, and the flange 80 on the shoe enters the groove 84 on the carrier 46 between the flange 110, and a further flange 112 formed on the carrier between grooves 56 and 84.
The piston rod 86 is then retracted, causing arms 72 and 73 to be pivoted upwardly. This pivotal movement of the shoe 77 causes the carrier 46 to be swung out of the U-shaped slot 45 in the slide 30 upwardly from the broken line position at 46' in FIG. 2 to its inactive position illustrated at 46" (FIG. 2) by broken lines. In this position the carrier can be removed from the shoe 77 and replaced by another, if desired.
In use, it is preferred to employ two horseshoe-shaped receptacles 76, 77, and there may always be a new die in receptacle 76. As soon as the old carrier 46 has been swung into its inactive position (46" ), then, the piston in cylinder 104 may be actuated to advance its rod 105 axially, thereby shifting mechanism 70 to the position shown in part by broken lines in FIG. 1, and causing arm 72 and its shoe 76 to be shifted axially to the positions that were previously occupied by the arm 73 and its shoe 77. The piston in cylinder 87 is now once again energized to advance its rod 86 upwardly, thus causing the arms 72 and 73 to be pivoted downwardly from retracted to transfer positions.
This downward pivotal movement of the arm 72 will cause the new die carrier to be deposited in the pocket 45 in slide 30 adjacent to bolster assembly 48. The piston in cylinder 60 is now again actuated to shift locking member 52 toward the left in FIGS. 1 and 2 into locking engagement with the recess 56 in the newly deposited carrier 46. This locks the new die carrier in slide 30, so that the piston in cylinder 36 can now be actuated to retract die slide 30 away from shoe 76, back to its extrusion position as illustrated in full lines in the drawings. Since during this retraction of slide 30, member 52 is in locking position, the new die carrier 46 will be drawn out of the shoe 76, and into registry with the main ram of the press. The piston in cylinder 87 may then again be energized to retract its rod 86 and swing the arms 72 and 73 to their retracted positions.
The die carrier previously removed from the press by shoe 77 can then be replaced by a new carrier and die.
When it is next decided to change the die, the arms 72 and 73 will again be swung to their transfer positions. This time the die slide 30 will deposit the die carrier, which is to be removed, into the now-registering shoe 76, which will thereafter be elevated to retracted position for removal of the die and its carrier The piston in cylinder 104 is then actuated to retract rod 105 to shift the die changing mechanism 70 back to its full line position (FIG. 1), after which the arms 72, 73 may be pivoted downwardly to deposit the new die carrier and die from the shoe 77 into the die slide 30.
From the foregoing it will be apparent that a relatively simple and compact mechanism for exchanging dies in extrusion presses has been provided. Moreover, this novel mechanism avoids unnecessary shutdown time during the changing of a die.
While in the embodiment illustrated the arms 72 and 73 are mounted to be pivoted in unison about sleeve 74 by means of a single cylinder 87 and rod 86, it will be apparent that the arms could be mounted for pivotal movement by gearing, or for pivotal movement independently of one another on sleeve 74, as for example, by two separate cylinders similar to cylinder 87. Both such cylinders, of course, would be mounted for axial shifting movement with the mechanism 70 on shafts 66 and 67. Moreover, the cylinder 104 may be actuated selectively to shift mechanism 70 in any desired manner. For example, if desired, the cylinder 104 may be actuated to return mechanism 70 to its full line position (FIG. 1) adjacent the platen 22 each time the empty shoe 76 is returned upwardly to its inactive position following the deposit of a new carrier 46 in the slide 30.
While the invention has been described in connection with a specific embodiment thereof, it will be understood, then, that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention or the limits of the appended claims.
During extrusion, the die is held in axial alignment with the billet container. In known presses to change the die, a slide, on which the die carrier is mounted, is actuated to move the die carrier from center position to a position at one side of the press where the die can be more conveniently removed from the press and replaced.
The primary object of this invention is to provide means for moving a die carrier to a more convenient location for removal of a die and substitution of another die.
Another object of the invention is to provide apparatus of the nature which will minimize handling during die changing.
Another object of this invention is to provide a novel die-changing mechanism of the type described, which may readily be automated to automatically remove one die from a press and replace it with another.
A more specific object of this invention is to provide a novel die changing mechanism capable of handling a plurality of dies, so that one die can be removed from a die slide and immediately replaced by another.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.
In the drawings:
FIG. 1 is a fragmentary plan view of an extrusion press made in accordance with one embodiment of this invention, parts thereof being cut away and shown in section; and
FIG. 2 is a fragmentary sectional view taken along the line 2-2 in FIG. 1 and looking in the direction of the arrows.
In the drawings 22 denotes the conventional end platen, 23 designates the conventional main tie bolts (FIG. 2) and 24 denotes the usual container housing of an extrusion press. Housing 24 is mounted in usual manner on rods 25 (FIG. 2) for reciprocable movement parallel to the tie bolts 23.
20 DENOTES GENERALLY A DIE SLIDE ASSEMBLY FOR THE PRESS. This assembly 20 comprises a die slide 30, which is mounted on guide brackets 32 and 34 for rectilinear sliding movement on the face of the platen 22 transversely of the axis of the container in housing 24. Slide 30 is reciprocated by a piston 40 which is connected to the slide 30 by piston rod 42 and coupling 43. Piston 40 reciprocates in a cylinder 36, which is mounted by bracket 38 on platen 22.
Removably seated coaxially in an arcuate or U-shaped pocket 45 in slide 30 are a cylindrical die carrier 46, and the supporting bolster 48 (FIG. 1). The forward end of the carrier (lower end in FIG. 1) projects axially beyond the corresponding end of the pocket. Die carrier 46 has an axial bore 47 in which a die (not illustrated) is adapted to be secured in the usual manner. Pocket 45 faces diagonally upwardly and toward the left in FIG. 2, so that the carrier 46 and the associated bolster 48 may be inserted into, or withdrawn from, the pocket radially as indicated by the arrows 49 in FIG. 2.
Mounted for sliding movement on slide 30 radially of carrier 46 is a yoke-shaped locking collar or gate 52, which has a tongue 53 that engages in a groove 56 formed in the periphery of die carrier 46 coaxially thereof, thereby to secure the die carrier against axial movement in pocket 45.
Locking member 52 is secured to a pair of spaced, parallel operating rods 58 and 59, which extend slidably through die slide 30 and are secured to a crossplate 64. Crossplate 64 is fastened to the piston rod 62 of a piston (not illustrated) which reciprocates in a cylinder 60 that is mounted to project laterally from slide 30.
Fixed at one end in the platen 22 at the side thereof remote from cylinder 36, and projecting from the face of the platen parallel to the main tie bolts 23 and to the axis of the container housing 24, is a shaft 66. Mounted beneath and parallel to shaft 66 is a second shaft 67 (FIG. 2), opposite ends of which are fixed in spaced brackets 68 that are welded to an I-beam 69 that extends along the bottom of the press at one side thereof.
Shafts 66 and 67 support a die changing mechanism 70, comprising a pair of spaced, parallel arms 72 and 73, which are pivotally mounted on a sleeve or bushing 74 (FIG. 2) that is mounted for axial sliding movement on shaft 66. At their free, or right-hand ends as illustrated in the drawings, the arms 72 and 73 carry identical, generally arcuate or U-shaped shoes or receptacles 76 and 77, respectively, which are integral with the respective arm 72, 73. Medially of its ends each shoe 76, 77 is formed with an arcuate groove 78, disposed between arcuate flanges 79 and 80. In each shoe the flange 79 projects in a radial direction slightly beyond the adjacent flange 80, and has a chamfered lower end 79', which registers with a like end 80' on flange 80.
Remote from the shoes 76 and 77, arms 72 and 73 have projections 82 and 83, respectively, which are pivotally connected by a shaft 81 and a link 85 to the upper end of a piston rod 86. The piston (not illustrated), that actuates rod 86, is housed in a cylinder 87, which is pivotally connected at its lower end by pin 88 to a collar 89 that is carried by a bushing or sleeve 90, that is axially slidable on shaft 67.
Secured at their lower ends to opposite ends of the sleeve 90, and adjacent their upper ends to opposite ends of the sleeve 74, are two, spaced, parallel plates or webs 92, 93. Adjustably secured in a crossbar 95, which extends between the upper ends of the plates 92 and 93 are two, adjustable stops 96, the lower ends of which overlie the projections 82 and 83 on the arms 72 and 73, respectively. The bolts 96 can be adjusted to limit pivotal movement of the arms 72 and 73 clockwise (FIG. 2) about the axis of shaft 66.
Arms 72 and 73 are separated by a spacer 97; and end plates 92 and 93 are separated from arms 72 or 73, respectively, by further spacers 98. The spacers are mounted on sleeve 74. Beneath shaft 66 the end plates 92 and 93 are further secured in spaced relation to one another by a reinforcing plate 99 (FIG. 2), opposite sides of which are bolted or otherwise secured to the confronting faces of end plates 92 and 93.
Secured to the side of platen 22 to the rear of the die-changing mechanism 70 is a cylinder 104 (FIG. 1). The rod 105 (FIG. 2) of a piston (not shown), which reciprocates in this cylinder, is secured at its outer end by a plate 106 (FIG. 2) to the rear face of plate 92 approximately medially of the upper and lower ends thereof. Cylinder 104 is mounted so that piston rod 105 reciprocates parallel to shafts 66 and 67, thereby to impart reciprocable motion to the mechanism 70 axially of these shafts.
Normally die slide 30 is positioned, as illustrated in the drawings, so that the die carrier 46 registers axially with the main ram of the press; and the locking member 52 is engaged in groove 56 in carrier 46 to hold the carrier against axial movement relative to the bolster assembly 48. Also, the piston rod 86 (FIG. 2) normally is in its retracted position, so that arms 72 and 73 are held in retracted positions. The piston rod 105, too, is in its retracted position, so that the die-changing mechanism 70 is located on the shafts 66 and 67 immediately adjacent to platen 22, that is, in its solid line position in FIG. 1. In this position flange 80 of shoe 77 will register axially with groove 84 in carrier 46.
When it is desired to change dies piston rod 86 is actuated to cause arms 72 and 73 to pivot (clockwise in FIG. 2) downwardly from their inoperative positions (indicated in dash lines in FIG. 2) to their operative positions (shown in solid lines). The piston in cylinder 60 is now actuated to move crossmember 64 towards the right in FIG. 1, thereby to retract the locking member 52, and to disengage the member 52 from the die carrier 46. Simultaneously piston 40 is actuated to advance the die slide 30 toward the left in FIGS. 1 and 2 far enough to cause the projecting end of carrier 46 to be pushed over the chamfered ends 79' and 80' of the shoe 77 until the flange 110 on the carrier 46 drops into the registering recess 78 in the shoe 77, and the flange 80 on the shoe enters the groove 84 on the carrier 46 between the flange 110, and a further flange 112 formed on the carrier between grooves 56 and 84.
The piston rod 86 is then retracted, causing arms 72 and 73 to be pivoted upwardly. This pivotal movement of the shoe 77 causes the carrier 46 to be swung out of the U-shaped slot 45 in the slide 30 upwardly from the broken line position at 46' in FIG. 2 to its inactive position illustrated at 46" (FIG. 2) by broken lines. In this position the carrier can be removed from the shoe 77 and replaced by another, if desired.
In use, it is preferred to employ two horseshoe-shaped receptacles 76, 77, and there may always be a new die in receptacle 76. As soon as the old carrier 46 has been swung into its inactive position (46" ), then, the piston in cylinder 104 may be actuated to advance its rod 105 axially, thereby shifting mechanism 70 to the position shown in part by broken lines in FIG. 1, and causing arm 72 and its shoe 76 to be shifted axially to the positions that were previously occupied by the arm 73 and its shoe 77. The piston in cylinder 87 is now once again energized to advance its rod 86 upwardly, thus causing the arms 72 and 73 to be pivoted downwardly from retracted to transfer positions.
This downward pivotal movement of the arm 72 will cause the new die carrier to be deposited in the pocket 45 in slide 30 adjacent to bolster assembly 48. The piston in cylinder 60 is now again actuated to shift locking member 52 toward the left in FIGS. 1 and 2 into locking engagement with the recess 56 in the newly deposited carrier 46. This locks the new die carrier in slide 30, so that the piston in cylinder 36 can now be actuated to retract die slide 30 away from shoe 76, back to its extrusion position as illustrated in full lines in the drawings. Since during this retraction of slide 30, member 52 is in locking position, the new die carrier 46 will be drawn out of the shoe 76, and into registry with the main ram of the press. The piston in cylinder 87 may then again be energized to retract its rod 86 and swing the arms 72 and 73 to their retracted positions.
The die carrier previously removed from the press by shoe 77 can then be replaced by a new carrier and die.
When it is next decided to change the die, the arms 72 and 73 will again be swung to their transfer positions. This time the die slide 30 will deposit the die carrier, which is to be removed, into the now-registering shoe 76, which will thereafter be elevated to retracted position for removal of the die and its carrier The piston in cylinder 104 is then actuated to retract rod 105 to shift the die changing mechanism 70 back to its full line position (FIG. 1), after which the arms 72, 73 may be pivoted downwardly to deposit the new die carrier and die from the shoe 77 into the die slide 30.
From the foregoing it will be apparent that a relatively simple and compact mechanism for exchanging dies in extrusion presses has been provided. Moreover, this novel mechanism avoids unnecessary shutdown time during the changing of a die.
While in the embodiment illustrated the arms 72 and 73 are mounted to be pivoted in unison about sleeve 74 by means of a single cylinder 87 and rod 86, it will be apparent that the arms could be mounted for pivotal movement by gearing, or for pivotal movement independently of one another on sleeve 74, as for example, by two separate cylinders similar to cylinder 87. Both such cylinders, of course, would be mounted for axial shifting movement with the mechanism 70 on shafts 66 and 67. Moreover, the cylinder 104 may be actuated selectively to shift mechanism 70 in any desired manner. For example, if desired, the cylinder 104 may be actuated to return mechanism 70 to its full line position (FIG. 1) adjacent the platen 22 each time the empty shoe 76 is returned upwardly to its inactive position following the deposit of a new carrier 46 in the slide 30.
While the invention has been described in connection with a specific embodiment thereof, it will be understood, then, that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention or the limits of the appended claims.