US2890487A

US2890487A - Spool casting die and core structure

Info

Publication number: US2890487A
Application number: US575739A
Authority: US
Inventors: Louis H Morin
Original assignee: Coats and Clark Inc
Current assignee: Coats and Clark Inc
Priority date: 1956-04-03
Filing date: 1956-04-03
Publication date: 1959-06-16
Anticipated expiration: 1976-06-16

Description

E AND CORE STRUCTURE June 16, 1959 Filed April 3, 1956 Unite States Patent SPOOL 'CASTING DIE AND CORE STRUCTURE Louis H. Morin, Bronx, N.Y., assignor to Coats & Clark Inc., New York, N.Y., a corporation of Delaware Application April 3, 1956, Serial No. 575,739

16 Claims. (Cl. 18-42) This invention relates to the production of cast or moulded spools. More particularly, the invention deals with a die and core structure for producing products of the kind under consideration. Still more particularly, the invention deals with a novel type of core structure, the same to facilitate free separation of the cores one from the other and from the cast or moulded product.

The novel features of the invention will be best understood from the following description, when taken together with the accompanying drawing, in which certain embodiments of the invention are disclosed and, in which, the separate parts are designated by suitable reference characters in each of the views and, in which:

Fig; l is a diagrammatic sectional view of part of the die and core mechanism, including portions of associate parts for use in producing spools in accordance with the method, the several parts being shown in the casting or moulding position, with the section through the cores taken on the line 11 of Fig. 3.

Fig. 1a is a detailed sectional view of a portion of one end of a spool made according to my invention.

Fig. 2 is an isomertric View of a core unit detached, with part of the construction broken away.

Fig. 3 is a cross-sectional view through an assemblage of two core units, taken substantially centrally of the core members or elements of the unit.

Fig. 4 is an inside perspective View of one of the core members or elements showing mainly a core finger thereof; and

Fig. 5 is a perspective detailed view of one of the core members or elements, including a base part, with a portion broken away.

In order to illustrate the die and core structure in assemblage for production of a spool, preferably a plastic spool, I have illustrated, somewhat diagrammatically in Fig. l of the drawing, the various die and core parts and portions of associated parts in the closed or casting or moulding position. In said figure, represents the face view of one part of a die, the dies being movable in planes perpendicular to the showing in the drawing. At 11 is indicated part of a transfer device, including a tapered transfer pin l2. 13 represents the sprue or gate leading into divided sprue passages 14 which extend to the rim forming cavities 15 of the dies to form the rims 16 of the resulting spool 17. The dies are also fashioned to partially form the outer annular label retaining flanges 18 'upon the outer surface of the rims 16, a cavity 19 to receive the pin 12 and a cavity 20 to mould a sleeve-like part 21 upon the pin and also including runners 22, which extend to the wall of the spool 17 At 23 I have indicated a small portion of core slides for actuating core assemblages 24, each assemblage including a core unit 25.

Each assemblage 24 is of the same general construction and, for this reason, the brief description of one will apply to the other and like references will identify like parts. 26 represents the outer cylinder or shell of the assemblage, 27 the inner cylinder or shell, adjacent surfaces of the shells being shaped to form therebetween a water cooling jacket 28, through which cooling water may be ciroulated by pipes, one of which is indicated at 29.

O or other sealing rings 30 are provided between adjacent surfaces of the

shells

26 and 27 in order to seal the jacket 28. Supported within the inner shell of each;

assemblage is a core shell or liner 31, which has, at its inner end, an annular core portion 32 for forming an annular groove 33 in each rim portion 16 of the resulting spool and also to form the inner diameter portionof the annular rim 18, as will be apparent from a consideration of Fig. l of the drawing. The outer end portionofi. each core shell 31 has a shoulder 34 which abuts the inner shell 27 for definite positioning of the core end 32' in the cavity 15.

The core units 25 are arranged within the core shell or liners 31 and, here again, as each unit 25 is of the same construction, the brief description of one unit will apply to both. One of these units is shown in the isometric view of Fig. 2 detached and it will appear that each unit 25 comprises an assemblage of four similar core members or elements 35. Each element 35 comprises an-v eniarged base'portion 36 which is adapted to seat upon the end of the core shell or liner 31, as seen at 37 in Fig. l of the drawing.

Extending from the base portion 36 is a long body portion 38; these body portions of the respective core members or elements define a cylinder, the bore of which is indicated at 39. The portions 38 terminate in what may be termed shoulders or ledges 44), from which extend core fingers 41 of each element or member, as is indicated in Fig. 5 of the drawing, which are tapered from the shoulders 40 outwardly to the free ends thereof and which have smaller arcuate inner surfaces 42 than the larger arcuate outer surfaces 43, as will clearly appear from a consideration of Figs. 3 and 5 of the drawing. This construction forms on the lateral sides of each finger 41 contracted

side walls

44 and 45, that is, each such side wall is tapered from its outer to its inner end.

Side walls

44 and 45 are partly defined by longitudinally inclined, bevelled

shoulders

46 and 47, respectively. The shoulders 46 face radially outwardly; whereas, the shoulders '47 face radially inwardly and, assuming that a section were taken substantially centrally through the assemblage of the two core units, as is noted in Fig. 3 of the drawing, the inclination of the shoulders is such as to position the

abutting shoulders

46 and 47 substantially centrally with respect to the radial dimension of the core portion of the assembled core units. These shoulders serve to positively support the assembled core units to resist the pressure of injection of the moulding material which is pressure injected into the die cavities in forming the cylindrical portion of the spool 17 around the assem-- bled core units, as clearly indicated in Fig. 1 of the draw-- ing. It will also be apparent that the end extremities of the fingers 41 of one core unit terminate in spaced rela-- tion to the shoulders 4i) of the other core unit, as indicated at 41' in Fig. l of the drawing, in order to form the end wall portions 48 at the ends of the spool, between which end wall portions there would be openings equivalent in size to the cross-sectional area of the core fingers 41 of the opposed core unit. These portions are shown at the upper right of Fig. 1 and at the lower left in Fig. 1 in alinement with the walls 48.

Supported in the bores 39 are mounting end portions 49 of outwardly tapered core pins 50, which extend into the bore 51 formed by the assembled core units 25 and are arranged in spaced relation thereto so as to form the inner small diameter tubular portion 52 of the resulting spool. It is also preferred that, where the mounting portions 4? join the pins 50, the core pins are fashioned, as

cavities to form the inner annular label retaining flanges 55 at end portions of the spool. However, in some instances, these inner flanges 55 are dispensed with.

Suitable shimmed shoulders 56 are provided in the base of the core units for bringing abutting surfaces 50' of the core pins 50 into engagement with each other. It will also appear that suitable keys, diagrammatically shown at 57 in Fig. 1 of the drawing, are employed to extend into the base portion 36 to control alinement of the two' core units one with respect to the other in movement of thecore units into and out of the area of the die cavity, so as to remove the cast or moulded spool 17 when the die parts are separated.

On completing this operation, the transfer device 11 is actuated to move the cast or moulded spool, together with the gate portions 58 toa trimming station where these gate portions 58, as well as the sleeve 21 and its gate extensions are trimmed from the spool, thus producing a finished end product preparatory for the mounting of thread thereon and application of end labels. In this last named operation, it will be apparent that means will be provided to strip the sleeve 21 from the transfer pin 12, preparatory to returning the pin to the casting position.

In the above described operation of separating the core units 25, it will be apparent that this operation will be performed without exerting any stress or strain upon the cylindrical walls of the cast or moulded spool by reason of the tapered wall structure of the separate core fing ers 41 of each core member or element. In other words, the instant there is any relative movement between the core units, the engaged surfaces will become free for free travel of the core units to their fully opened position. Again, in bringing the core units back into assembled relationship, the widespread throats between adjacent surfaces of the core fingers 41 of each member or element provide free entrance of the contracted end portion of the core fingers 41 of the opposed elements, until such time as these elements are brought into snug and firm engagement with each other and, at this time, the shoulders 34 will serve to definitely check movement of the core units toward each other.

For purposes of description, the spool may be said to comprise an inner central tubular portion and an outer barrel having the integral rim ends. It will be noted, from a consideration of Fig. 3 of the drawing, that the

shoulders

46 and 47 are preferably rounded to provide smooth action in assembling and separating the core fingers, it being understood, in this connection, that, when the core fingers are in closed position within the die cavity, all surfaces of the core fingers are held in firm abutting engagement with each other.

It will appear, from a consideration of Fig. 1 of the drawing, that the base part of each core unit fits snugly upon backing plates 59 which, in turn, abut the slides 23.

In the production of spools as disclosed, it will be apparent that, in using thermoplastic materials, the materials are injected into the cavities of the dies and around the cores at high pressure at about 20,000 pounds per square inch. This is essential by virtue of the extremely thin walls which are formed in the resulting spool product. This pressure is applied to the core fingers of the assembled cores and is taken up by the snug engagement and fitting of the fingers one with the other and reinforced by the interengaging

shoulders

46 and 47 on these core fingers.

' After the spool product has been moulded in the die cavities, the cores are withdrawn and, in this operation, there normally develops a substantial drag, which is obviated with my present construction by virtue of the tapering mating surfaces of the core fingers which provides a more or less instantaneous relief as the cores are drawn apart. This method of procedure further eliminates wear upon the core units and eleminates the necessity of lubricating the units which usually has been the practice, particularly where the drag prevailed.

It will also be apparent that the core slides are firmly backed by the means for actuating the same, so as to positively resist axial stresses or strains upon the core units which would tend to separate the same, particularly in injection of the moulding material between adjacent surfaces of the cores at the shoulders or ledges 40 in forming the end wall portions 48 of the resulting spool.

In the operation of the core assemblages, it will be apparent that each complete assemblage is movable with the cores and moves with the core slides. The particular couplings and mountings are purposely omitted to simplify the present showing. In this movement, it will be apparent that flexible tubing, not shown, is coupled with the pipes 29 to compensate for movement of the core assemblages.

It will be apparent that, while the core units 25 are generally of like construction, they are what might be termed left and right hand for proper fitting and, while in the accompanying drawing, each core unit is shown as comprising four core fingers, this is only by way of illustrating a simple adaptation of the invention. The number of fingers employed in each unit can be modified to suit the resulting product to be attained.

By way of summary, the device of Fig. 2, identified as 25, is termed a core unit; it comprises a plurality of separate, abutting core members or core elements 35, one of which is separately shown in Fig. 5. The lower portion of the core unit of Fig. 2, identified by

numerals

36 and 38, is termed a base, and the upper portion comprises a plurality of core fingers 41. The core member or element 35 of Fig. 5 has a lower portion, identified by

numerals

36 and 38, which may be termed a base portion or base part.

' It is to be noted that each core member 35 comprises a single integral part and is replaceable in the core unit. The provision of the shoulders or

ledges

46 and 47 on each core finger represents a simplified construction for enabling these fingers to engage the fingers of an opposite core unit. Also, each core member has, in the base portion thereof, an outer shoulder portion 37 and an inner shoulder portion 56 which aid in supporting the core members in die casting position and in moving them to and from die casting position.

This application is a continuation-in-part of copending applications Ser. Nos. 363,364 and 486,664, filed June 22, 1953, and February 7, 1955, respectively.

- Having fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A die and core structure for moulding spool bodies having a central tubular portion, a barrel having enlarged rim ends, each rim end being partially defined by an annular groove, and circumferentially spaced end walls integrally united with the carrel and central tubular portion, said structure comprising dies movable toward and from each other and including cavities partially forming the barrel and enlarged rim ends, a pair of opposed core units movable toward and from each other at right angles to the movement of the dies, each core unit comprising a group of circumferentially spaced, identical, integral core elements; each core element comprising a base portion at the inner end thereof, an intermediate body portion having an outer end, and a core finger extending from said outer end of the body portion and terminating in a free end; said base and body portions of said group of core elements collectively forming circumferentially continuous base and body portions, respectively, having a throughbore; said core fingers of said group of cole elements having a circumferentially spaced disposition; the fingers of one core unit interfitting with the fingers of the opposed core unit in forming a circumferentially continuous core within the dies to partially form the barrel and central tubular portion of the result ing spool, the core fingers of each unit tapering fi'om the body portion outwardly to the free end of the fingers, and said free end of the core fingers terminating short of the body portion of the opposed core unit to form cavities defining the circumferentially spaced end walls of the resulfing spool.

2. A structure as defined in claim 1, in which each finger of each of the core units includes, at one lateral side thereof, an inwardly facing shoulder and, at the other lateral side thereof, an outwardly facing shoulder.

3. A structure as defined in claim 2, in which the shoulders are inclined from inner to the outer free ends of the fingers, wherein the outwardly facing shoulders of the fingers of one unit firmly engage the inwardly facing shoulders of the fingers of :a companion unit when the units are in assembled relationship Within the die cavity.

4. A structure as defined in claim 3, wherein means is provided on inner and outer sides of said base portions for keying the core units to maintain meshing alinement of the core units one with respect to the other.

5. A structure as defined in claim 4, wherein each core unit has radially outwardly thereof inner and outer shells with a water jacket disposed therebetween, means for circulating water through the water jacket, a core shell encircling the body portion of each core unit, and said core shell including an annular core portion extending into the annular groove partially defining the enlarged rim end of the resulting spool.

6. A structure as defined in claim 5, wherein the annular core portion of each core shell, in conjunction with the die cavity, collectively form a cavity at the end of the rim for producing, on the resulting spood body, an annular outwardly projecting flange on each rim.

7. A structure as defined in claim 4, wherein each core unit has a tapered core pin spaced radially inwardly of each said core fingers for defining the bore of the can tral tubular portion of the resulting spool, and wherein means is provided on each core pin to form an annular cavity for forming a circumferential flange extending integrally from each end of said central tubular portion of the spool.

8. A structure as defined in claim 4, wherein a tapered transfer pin is supported between said dies, and the dies have cavities forming, around said transfer pin, a sleeve part having runners extending to the barrel forming portion of the dies, whereby the resulting moulded spool body can be supported and moved upon separation of the dies and core unit.

9. In core structures for forming molded products of the kind described, a first core unit comprising a plurality of similar core elements which, when assembled, define a hollow body portion extending from a base portion, each element including an outwardly tapered core finger extending from the body portion within side limits of the body portion, a pair of shoulders on the body portion disposed adjacent opposed lateral sides of said finger; and a second core unit having fingers interfitting with and snugly engaging the fingers of the first core unit and having shoulders, the shoulders of each unit being spaced from the extremities of the fingers of the other unit.

10. The core structure of claim 9 wherein the assembled fingers of said units define a circumferentially continuous bore throughout the major portion of the length of said fingers.

11. In core structures for forming molded products of the kind described, a first core unit comprising a plurality of similar core elements which, when assembled, define a hollow body portion extending from a base portion, each element including an outwardly tapered core finger extending from the body portion within side limits of the body portion, a pair of shoulders on the body portion disposed adjacent opposed lateral sides of said finger, a second core unit having a body portion, shoulders on said body portion, and fingers interfitting with and snugly engaging the fingers of the first core unit with outer end extremities of the fingers of each core unit spaced from the shoulders of body portions of adjacent core elements of the other core unit, the assembled fingers of the core units defining a circumferentially continuous bore throughout the major portion of the length of said fingers, a tapered side wall upon each lateral side of each finger, one of said lateral sides having an inwardly facing shoulder extending longitudinally thereof, the other lateral side having an outwardly facing shoulder extending longitudinally thereof, and the longitudinal shoulders of eachfinger engagingthe longitudinal shoulders of two adjacent fingers in firmly retaining the as; sembled fingers in position to resist inward and outward radial pressures to which said fingers are subjected.

12. The core structure of claim 11 wherein the longitudinal shoulders of the fingers are longitudinally inclined.

13. The core structure of claim 11 wherein the longitudinal shoulders of the fingers are longitudinally inclined and transversely rounded.

14. In a core structure of the kind described, first and second core units, each said unit comprising a group of circumferentially spaced, identical, integral, replaceable core elements; each core element comprising a base portion at the inner end portion thereof, an intermediate body portion having an outer end, and a core finger extending from said outer end of the body portion and terminating in a free end; said base portion having means for supporting the core element in association with the other core elements of the core unit; said body portion having a pair of shoulders on the outer end thereof disposed adjacent opposite lateral sides of the core finger; said core finger being of arcuate cross section and having outer and inner opposed surfaces that are tapered from the inner to the outer ends thereof, said finger having on opposite lateral sides thereof an inclined, longitudinal extending, transversely rounded shoulder, each said lateral side having a side Wall partially defined by said shoulder and tapered from the outer to the inner ends thereof, one of said shoulders facing outwardly and the other facing inwardly; said base and body portions of said group of core elements collectively forming circumferentially continuous base and body portions, respectively, having a thr-oughbore; the core fingers of each core unit being adapted to interfit with the core fingers of the other core unit to form a circumferentialy continuous core, said core units being relatively movable so as to dispose the free ends of the core fingers of each core unit close to but spaced from the shoulders on the body portions of the core elements of the opposite core unit; said interfitting core fingers being supported by the engagement of the shoulders of one core finger with the adjoining shoulders of a pair of opposite core fingers, the outwardly and inwardly facing shoulders of the core fingers of one core unit respectively engaging the inwardly and outwardly facing shoulders of the core fingers of the opposite core unit; and said interfitting core fingers defining a continuous bore which communicates with said throughbore.

15. In a core structure of the kind described, first and second core units, each said unit comprising a group of circumferentially spaced, identical, integral core elements; each core element comprising a base portion at the inner end portion thereof, an intermediate body portion having an outer end, and a core finger extending from said outer end of the body portion and terminating in a free end; said body portion having a pair of shoulders on the outer end thereof disposed adjacent opposite lateral sides of the core finger; said core finger being tapered from the inner to the outer ends thereof, said finger having on opposite lateral sides thereof an inclined longitudinal extending shoulder, one of said shoulders facing outwardly and the other facing inwardly; the core fingers of the first core unit being adapted to interfit with the core fingers of the second core unit to form a circumferentially continuous core, said core units being relatively movable so as to dispose .the free ends of the core fingers of each core unit close to but spaced from the shoulders on the body portions of the core elements of the other. core unit; said interfitting core fingers being supported by the engagement of the shoulders of one core finger with the adjoining shoulders of a pair of opposite core fingers, and the outwardly and inwardly facing shoulders of the core fingers of one core unit respectively engaging the inwardly and outwardly facing shoulders of the core fingers of the other core unit.

16. In a core structure of the kind described, first and second core units, each core unit comprising a group of circumferentially spaced core elements, each of said elements comprising an inner base portion, an intermediate body portion having an outer end, and an outer core finger of reduced cross section extending from said outer end of the body portion and terminating in a firee end; said core finger being tapered from the inner to the outer ends thereof, said finger having on opposite lateral sides thereof an inclined, longitudinal extending shoulder; the core fingers of the first core unit being adapted to interfit with the core fingers of the second core unit to form a circumfere'ntially continuous core, said core units being relatively movable so as to dispose the freeends of; the core fingers of each core unit close to but'spaced from the outer ends of the body portionsof the core elements of the other core unit; and said inter-fitting core fingers being supported by the engagement of the shoulders of each core finger with the adjoining shoulders of a pair of core fingers of the other core unit.

References Cited in the file of this patent UNITED STATES PATENTS 16,166- Smith, Jr. Dec. 2, 1856 806,783 Dayton Dec. 12, 1905 2,266,887- McCoy' Dec. 23, 1941 2,439,506 Christian Apr. 13, 1948 2,541,923 Huxhan Feb. 13, 1951-