The present invention relates to metal forming dies and the like, and in particular to a modular pilot assembly with self-contained stripper and associated method.
Metal forming dies, such as stamping dies and the like, are well known in the art. Progressive metal forming dies are unique, very sophisticated mechanisms which have multiple stations or progressions that are aligned longitudinally, and are designed to perform a specified operation at each station in a predetermined sequence to create a finished metal part. Progressive stamping dies are capable of forming complex metal parts at very high speeds, so as to minimize manufacturing costs.
Heretofore, the dies used in metal forming processes have typically been individually designed, one of a kind assemblies for a particular part, with each of the various components being handcrafted and custom mounted or fitted in an associated die set, which is in turn positioned in a stamping press. Not only are the punches and the other forming tools in the die set individually designed and constructed, but the other parts of the die set, such as stock lifters, guides, end caps and keepers, cam returns, pilots, etc. are also custom designed, and installed in the die set. Current die making processes require carefully machined, precision holes and recesses in the die set for mounting the individual components, such that the same are quite labor intensive, and require substantial lead time to make, test and set up in a stamping press. Consequently, such metal forming dies are very expensive to design, manufacture, and repair or modify.
Pilot assemblies, such as that disclosed in U.S. Pat. No. 4,342,214, are used for locating a work piece in successive forming stages of a machine, such as a punch press, where the work piece is progressively moved through the forming stages of the machine. The pilot assembly typically includes a pilot pin mounted to a movable die member of the machine for guiding entry into a previously formed hole in a work piece or in a companion die member as the die members are moved toward each other.
Large manufacturers of formed metal parts, such as those which supply parts to automobile companies and the like, have an extensive inventory of metal forming dies and related metal handling machinery. Through the years, such companies have standardized on several different styles and sizes of pilot punches and associated pins for use with their various dies, so as to maximize efficiencies when combining various tooling for a specific project. Similarly, the metal forming die industry generally has adopted such standard pilot punch and pin sizes and shapes to minimize the effort and expense of making, installing and maintaining the dies and related metal handling equipment. When a new die is designed and fabricated by a tool and die maker, the customer will often specify that the die maker use a specific shape and size of pilot punching pin, which is often one of several styles that are standard or non-custom, and are commercially readily available. Sometimes, the customer will actually provide to the die maker the pilot punch and pilot pins that it desires to be incorporated into a specific progressive metal forming die, or portion thereof.
While such prior pilot assemblies have proven generally successful, they are rather expensive and time consuming to construct and install in an associated die set, such that further improvements and enhancements to the same, as well as metal forming dies generally, would be clearly advantageous, and are disclosed herein.
One aspect of the present invention is a multi-station progressive metal forming die, having at least two mutually converging and diverging die members between which an elongate stock strip is shifted longitudinally to form parts from the stock strip, along with an improved modular pilot assembly with self-contained stripper. The modular pilot assembly includes a pilot sleeve operably supported on one of the die members, and having a generally cylindrical shape with an outer end portion oriented toward the stock strip, an oppositely disposed inner end portion oriented away from the stock strip, and a central aperture extending through the outer and inner end portions. The outer end portion of the pilot sleeve has a generally flat outer end oriented toward the stock strip, a generally recessed inner end oriented away from the stock strip, and an outer sidewall with at least one fastener relief therein having an arcuately shaped, radially inwardly curved relief sidewall that extends axially from the flat outer end to a generally flat, arcuately shaped relief end surface facing toward the stock strip and spaced axially outwardly a predetermined distance from the recessed inner end, as well as at least one axially extending ejector pin aperture which opens through the flat outer end and into the recessed inner end. The inner end portion of the pilot sleeve has a generally annularly shaped spring retainer collar, with an outer end oriented toward the stock strip, an inner end oriented away from the stock strip, and an outer sidewall with a diameter that is less than the diameter of the outer sidewall of the outer end portion of the pilot sleeve, thereby forming an annularly shaped spring groove adjacent the outer end of the spring retainer collar. The modular pilot assembly also includes a rigid pilot pin, having a portion thereof shaped for close reception in the central aperture of the pilot sleeve in an assembled condition, and including a circularly shaped innermost collar portion disposed adjacent the flat outer end of the pilot sleeve and shaped for close reception in a pilot hole in the stock strip, a generally frusto-conically shaped outer portion configured to engage the pilot hole in a stock strip and guide the stock strip to a predetermined position in an associated die forming station, and a base portion positioned opposite the frusto-conically shaped outer portion. The modular die assembly also includes at least one rigid ejector pin slidingly received and retained in the ejector pin aperture in the outer end portion of the pilot sleeve having an inner end oriented away from the stock strip and an outer end oriented toward the stock strip and protruding outwardly from the flat outer end of the outer end portion of the pilot sleeve when urged to an extended position to contact the stock strip and strip the same away from the pilot pin, and retracts towards the pilot sleeve when urged to a retracted position. The modular pilot assembly also includes a spring member having a generally hollow interior that is received onto and over the spring retainer collar on the inner end portion of the pilot sleeve, an outer end oriented toward the stock strip, received in the spring groove and operably engaging the inner end of the ejector pin to bias the ejector pin outwardly to the extended position, and an inner end oriented away from the stock strip and positioned adjacent to the base portion of the pilot pin in the assembled condition. The modular pilot assembly also includes a mounting screw having an enlarged head portion with a circular plan shape that is at least partially, closely received in the fastener relief in the outer end portion of the pilot sleeve, an annularly shaped inner face oriented away from the stock strip and abuttingly engaging the relief end surface of the fastener relief in the outer end portion of the pilot sleeve, and a threaded shank portion anchored in the one die member to securely, yet detachably mount the modular pilot assembly on the one die member in a manner which causes the ejector pin to automatically reciprocate between the retracted and extended positions relative to the pilot sleeve during operation of the metal forming die to ensure that the stock strip is consistently stripped away from the pilot pin.
Yet another aspect of the present invention is a modular pilot assembly with self-contained stripper for multi-station progressive metal forming dies having at least two mutually converging and diverging die members between which an elongate stock strip is shifted longitudinally to form parts from the stock strip. The pilot assembly includes a pilot sleeve configured for operable support on an associated die member, and having a generally cylindrical shape with an outer end portion oriented toward the stock strip, and oppositely disposed inner end portion oriented away from the stock strip, and a central aperture extending through the outer and inner end portions. The outer end portion of the pilot sleeve has a generally flat outer end oriented toward the stock strip, a generally recessed inner end oriented away from the stock strip, and an outer sidewall with at least one fastener relief therein having an arcuately shaped, radially inwardly curved relief sidewall that extends axially from the flat outer end face to a generally flat arcuately shaped relief end surface facing toward the stock strip and spaced axially outwardly a predetermined distance from the recessed inner end, as well as at least one axially extending ejector pin aperture which opens through the flat outer end and into the recessed inner end. The inner end portion of the pilot sleeve has a generally annularly shaped spring retainer collar, with an outer end oriented toward the stock strip, an inner end oriented away from the stock strip, and an outer sidewall with a diameter that is less than the diameter of the outer sidewall of the outer end portion of the pilot sleeve, thereby forming an annulary shaped spring groove adjacent the outer end of the spring retainer collar. The pilot assembly also includes a rigid pilot pin having at least a portion thereof shaped for close reception in the central aperture of the pilot sleeve in an assembled condition, and including a circularly shaped innermost collar portion disposed adjacent the flat outer end of the pilot sleeve and shaped for close reception in a pilot hole in the stock strip, a generally frusto-conically shaped outer portion configured to engage the pilot hole in the stock strip and guide the stock strip to a predetermined position in an associated die forming station, and a base portion positioned opposite the frusto-conically shaped outer portion. The pilot assembly also has at least one rigid ejector pin slidingly received and retained in the ejector pin aperture in the outer end portion of the pilot sleeve, having an inner end oriented away from the stock strip, and an outer end oriented toward the stock strip and protruding outwardly from the flat outer end of the outer end portion of the pilot sleeve when urged to an extended position to contact the stock strip and strip the same away from the pilot pin, and retracts toward the outer end portion of the pilot sleeve when urged to a retracted position. The pilot assembly also includes a spring member having a generally hollow interior that is received onto and over the spring retainer collar on the inner end portion of the pilot sleeve, an outer end oriented toward the stock strip, received in the spring groove and operably engaging the inner end of the ejector pin to bias the ejector pin outwardly to the extended position, and an inner end oriented away from the stock strip and positioned adjacent to the base portion of the pilot pin in the assembled condition. The pilot assembly also includes a mounting screw having an enlarged head portion, with a circular plan shape that is at least partially, closely received in the fastener relief in the outer end portion of the pilot sleeve, an annularly shaped inner face oriented away from the stock strip and abuttingly engaging the relief end surface of the fastener relief in the outer end portion of the pilot sleeve, and a threaded shank portion shaped for anchoring in the associated die member, to securely, yet detachably mount the pilot assembly on the associated die member in a manner which causes the ejector pin to automatically reciprocate between the retracted and extended positions relative to the pilot sleeve during operation of the metal forming die to insure that the stock strip is consistently stripped away from the pilot pin.
Yet another aspect of the present invention is a modular pilot sleeve assembly with self-contained stripper for multi-station progressive metal forming dies, having at least two mutually converging and diverging die members between which an elongate stock strip is shifted longitudinally to form parts from the stock strip, and at least one pilot pin to precisely locate the stock strip in the die stations. The pilot sleeve assembly includes a pilot sleeve configured for operable support on an associated die member, and having a generally cylindrical shape, with an outer end portion oriented toward the stock strip, and oppositely disposed inner end portion oriented away from the stock strip, and a central aperture extending through the outer end portion shaped to closely receive and selectively receive the pilot pin therein. The outer end portion of the pilot sleeve has a generally flat outer end oriented toward the stock strip, a generally recessed inner end oriented away from the stock strip, and an outer sidewall with at least one fastener relief therein having an arcuately shaped, radially inwardly curved relief sidewall that extends axially from the flat outer end face to a generally flat arcuately shaped end surface facing toward the stock strip and spaced axially outwardly a predetermined distance from the recessed inner end, as well as at least one axially extending ejector pin aperture which opens though the flat outer end and into the recessed inner end. The inner end portion of the pilot sleeve has a generally annularly shaped spring retainer collar, with an outer end oriented toward the stock strip, an inner end oriented away from the stock strip, and an outer sidewall with a diameter that is less than the diameter of the outer sidewall of the outer end portion of the pilot sleeve, thereby forming an annularly shaped spring groove adjacent the outer end of the spring retainer collar. The pilot assembly has at least one rigid ejector pin slidingly received and retained in the ejector pin aperture in the outer end portion of the pilot sleeve, having an inner end oriented away from the stock strip and an outer end oriented toward the stock strip and protruding outwardly from the flat outer end of the outer end portion of the pilot sleeve when urged to an extended position to contact the stock strip and strip the same away from the pilot pin, and retracts toward the pilot sleeve when urged to a retracted position. The pilot assembly also includes a spring member having a generally hollow interior that is received onto and over the spring retainer collar on the inner end portion of the pilot sleeve, an outer end oriented toward the stock strip, received in the spring groove and operably engaging the inner end of the ejector pin to bias the ejector pin outwardly to the extended position, and an inner end oriented away from the stock strip and positioned adjacent to the inner end of the spring retainer collar in the assembled condition. The pilot assembly also includes a mounting screw having an enlarged head portion with a circular plan shape that is at least partially, closely received in the fastener relief in the outer end portion of the pilot sleeve, an annularly shaped inner face oriented away from the stock strip and abuttingly engaging the relief end surface of the fastener relief in the outer end portion of the pilot sleeve, and a threaded shank portion shaped for anchoring in the associated die member to securely, yet detachably mount the pilot assembly on the associated die member in a manner which causes the ejector pin to automatically reciprocate between the retracted and extended positions relative to the pilot sleeve during operation of the metal forming die to ensure that the stock strip is consistently stripped away from the pilot pin.
Yet another aspect of the present invention is a method for making a multi-station progressive metal forming die having at least two mutually converging and diverging die members between which an elongate stock strip is shifted longitudinally to form parts from the stock strip, with the improvement of at least one modular pilot with self-contained stripper for precisely locating the stock strip in the die stations. The method includes forming a pilot sleeve for operable support on one of the die members, with a generally cylindrical shape having an outer end portion oriented toward the stock strip, and oppositely disposed inner end portion oriented away from the stock strip, and a central aperture extending through the outer and inner end portions. The method also includes forming the outer end portion of the pilot sleeve with a generally flat outer end oriented toward the stock strip, a generally recessed inner end oriented away from the stock strip, and an outer sidewall with at least one fastener relief therein having an arcuately shaped, radially inwardly curved relief sidewall that extends axially from the flat outer end to a generally flat arcuately shaped relief end surface facing toward the stock strip and spaced axially outwardly a predetermined distance from the recessed inner end, as well as at least one axially extending ejector pin aperture which opens through the flat outer end and into the recessed inner end. The method also includes forming the inner end portion of the pilot sleeve with a generally annularly shaped spring retainer collar, having an outer end oriented toward the stock strip, an inner end oriented away from the stock strip, and an outer sidewall with a diameter that is less than the diameter of the outer sidewall of the outer end portion of the pilot sleeve, thereby forming an annularly shaped spring groove adjacent the outer end of the spring retainer collar. The method also includes forming at least one rigid ejector pin with an inner end, and an outer end configured to protrude outwardly from the flat outer end of the outer end portion of the pilot sleeve when urged to an extended position to contact the stock strip, and to retract toward the pilot sleeve when urged to a retracted position. The method further includes inserting the ejector pin into the ejector pin aperture in the body portion of the pilot, such that the ejector pin is slidingly received and retained in the ejector pin aperture for longitudinal reciprocation therein between the extended and retracted positions. The method also includes selecting a spring member with a generally hollow interior, an outer end oriented toward the stock strip, and an opposite inner end oriented away from the stock strip. The method further includes positioning the hollow interior of the spring member onto and over the spring retainer collar on the inner end portion of the pilot sleeve, with the outer end of the spring member received in the spring groove, and abutting the inner end of the ejector pin, and the inner end of the spring member protruding inwardly away from the outer end portion of the pilot sleeve in a pre-assembled condition. The method also includes providing a pilot pin with a medial portion shaped for close reception in the central aperture of the pilot sleeve in an assembled condition, a tapered outer portion configured to engage the pilot hole in the stock strip and guide the stock strip to a predetermined position or centered condition in an associated one of the die forming stations, and an inner face portion position opposite the tapered outer portion. The method also includes inserting the pilot pin into the central aperture of the pilot sleeve, such that the tapered outer portion of the pilot pin protrudes outwardly from the flat outer end of the outer end portion of the pilot sleeve to define an assembled condition. The method also includes forming a non-threaded blind hole pocket in the mounting face of one of the die members, with a cylindrical sidewall shaped to closely receive and retain at least a portion of the outer end portion of the pilot sleeve therein. The method also includes forming a threaded mounting screw aperture in the mounting face of the one die member, at a location spaced laterally apart from the pilot pocket a predetermined distance. The method also includes inserting the pilot sleeve in the assembled condition into the pilot pocket in the one die member with at least the outer sidewall of the outer end portion of the pilot sleeve closely received and retained therein so as to accurately locate the pilot assembly on the one die member, and with the fastener relief in the body portion of the pilot sleeve facing and aligned with the mounting screw aperture in the one die member. The method further includes selecting a mounting screw having an enlarged head portion with a circular plan shape sized for close reception of at least a portion thereof in the fastener relief in the body portion of the pilot sleeve, an annularly shaped inner face sized for abutment with at least a portion of the relief end surface of the fastener relief in the body portion of the pilot, and a threaded shank portion. The method also includes inserting the threaded shank portion of the mounting screw axially into the mounting screw aperture in the mounting face of the one die member, such that at least a portion of the enlarged head portion of the mounting screw is closely received in the fastener relief and adjacent the relief sidewall on the outer end portion of the pilot sleeve. The method also includes tightening the mounting screw in the mounting screw aperture in the one die member, thereby abuttingly engaging the inner face of the mounting screw head portion securely against the relief end surface of the fastener relief in the outer end portion of the pilot sleeve to securely, yet detachably, mount the pilot assembly on the one die member in a manner which causes the ejector pin to automatically reciprocate between the retracted and extended positions relative to the pilot sleeve during operation of the metal forming die to insure that the stock strip is consistently stripped away from the pilot pin.
Yet another aspect of the present invention is a pilot assembly that can be easily installed in an associated die member by simple machining a single pocket and a single tapped retainer hole therein. The pilot assembly has a self-contained stripper with no loose pieces or parts, is constructed from fewer components than prior art pilot devices and positively prevents the stock strip from sticking to the pilot pin. The pilot assembly includes a pilot sleeve with a central aperture configured to receive and retain therein one of a plurality of differently sized and shaped, conventional, and/or commercially available, pilot pins to facilitate the use of common parts throughout the metal forming die. The body portion of the pilot sleeve itself provides the precise location of the stripper assembly in an associated die pad at a location close to the stock strip. The stripper assembly has a modular design that can be economically manufactured, has a small profile and footprint, and can be easily assembled and disassembled from an associated die member. Due to the design of the pilot assembly, the ejector pins can be located in close proximity to the pilot pin, so as to positively and dependably, repeatedly strip the stock strip from the pilot pin. The pilot assembly has a single screw mounting system for quick and easy installation in an associated die member. The pilot sleeve can be machined from a single piece of solid material in one setup to achieve tighter tolerances and better concentricity between the pilot sleeve and pilot pin, as well as reduced manufacturing cost. The pilot assembly is efficient in use, economical to manufacture, capable of the long operating life, and particularly well adapted for the proposed use.
These and other advantages of the invention will be further understood and appreciated by those skilled in the art by reference to the following written specification, claims, and appended drawings.
For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal” and derivatives thereof shall relate to the invention as oriented in
The reference numeral 1 (
The term “die member,” as used herein, refers to any portion of a metal forming die or die set, including, but not limited to, an upper die member or a die shoe, a lower die member or a die shoe, and all other die components, whether stationary or reciprocating, including a reciprocating pressure pad, or the like. In the illustrated example, the pilot assembly 1 is shown mounted in a reciprocating upper die pad 3 located above a lower stationary die shoe 4. However, as will be appreciated by those skilled in the art, pilot assembly 1 can be mounted in other types of die members and/or components in a variety of different positions and orientations, as necessary to precisely locate the stock strip 5 in the various workstations 102 of a metal forming die 100.
The illustrated pilot sleeve 10 (
Since the illustrated pilot sleeve 10 has a one-piece construction formed from a solid bar of rigid material, such as metal or the like, preferably, all machining operations on the solid bar of rigid material are made during a single machine setup, so as to achieve greater accuracy and consistency of the pilot sleeve 10, as well as reduced manufacturing costs. The outer end portion 11 of the illustrated pilot sleeve 10 has a plurality of ejector pin apertures 20 having a substantially identical configuration and arranged in a circumferentially spaced apart, mutually parallel, axially extending pattern through the outer end portion 11 of pilot sleeve 10 to insure effective and consistent stripping of the stock strip 5 from the pilot pin 35. As best shown in FIGS. 4 and 11-13, the illustrated pilot sleeve 10 includes four ejector pin apertures 20 which are spaced opposite from one another on the flat outer end 14 of pilot sleeve 10, and are radially positioned close to the central aperture 13 of pilot sleeve 10, so as to improve the stripping action of the same. The illustrated pilot assembly 1 also includes four substantially identical ejector pins 42 which are slidingly received and retained for reciprocation in the ejector pin apertures 20 of the outer end portion 11 of the pilot sleeve 10. As best illustrated in
As best illustrated in
The illustrated spring member 48 comprises a conventional closed coil spring, which may have partially flattened or ground ends 50, 51 to more securely abut the inner ends 43 of ejector pins 42, as well as the bottom of the die pocket 80 in which the pilot assembly 1 is to be mounted, as described in greater detail hereinafter.
With reference to
The pilot 1 is assembled by inserting four ejector pins 42 into the associated ejector pin holes 20 in the outer end portion 11 of pilot sleeve 10, with the enlarged circular outer ends or heads 50 oriented away from the stock strip 5. Retainer ring 65 is then inserted into the retainer groove 64 adjacent the inner end of spring retainer collar 25, as best shown in
With reference to
The assembled pilot 1 is then aligned with and inserted into the pressure pad 3 in the manner illustrated in
The pilot sleeve and related pilot assembly 1 may be readily removed from die member 3 by simply reversing the sequence of the installation steps described above. In the illustrated example, a puller tool 68 (
As will be appreciated by those skilled in the art, pilot assembly 1 can be provided in a wide variety of different sizes to accommodate many different metal forming die applications. The all-in-one, modular construction of pilot assembly 1 not only provides a self-contained stock stripper that uses only one spring, but can be quickly and easily installed directly in a die member using simple machining techniques, and a single mounting screw.
Pilot assembly 1 has an uncomplicated construction with relatively few components and is therefore quite durable and economical to manufacture. The single mounting screw attachment of the pilot assembly to an associated die member provides quick and easy installation and removal. The spring member 48 and pilot pin 35 are backed up or axially supported by the die member itself for greater strength and convenience. Pilot assembly 1 has a self-contained stripper which positively separates the stock strip from the pilot during operation of the metal forming die, and provides a very compact, low profile shape that can be used at various locations and orientations on the various die members. The installation of the pilot assembly 1 can be achieved with simple machining, so as to reduce installation time and cost. The pilot sleeve portion 10 of the pilot assembly 1 is configured to receive and retain a wide variety of differently sized and shaped pilot pins therein, partially those with a conventional and/or commercially available configuration, so as to accommodate many different applications and users.
In the foregoing description, it will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless these claims by their language expressly state otherwise.
The present application is related to commonly assigned, co-pending U.S. provisional patent application Ser. No. 61/581,311, filed Dec. 29, 2011, entitled PILOT SLEEVE AND METHOD FOR METAL FORMING DIES AND THE LIKE, which is incorporated herein by reference, and claims priority thereto under 35 U.S.C. §119, as well as copending U.S. non-provisional patent application Ser. No. ______, filed even date herewith, entitled MODULAR PILOT ASSEMBLY WITH SELF-CONTAINED STRIPPER AND METHOD, which is also incorporated herein by reference.
Number | Date | Country | |
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61581311 | Dec 2011 | US |