CA1173619A - Method of molding a suspension idler - Google Patents

Abstract

Abstract of the Disclosure A conveyor suspension idler mold apparatus for molding a one-piece, elongated, flexible polymer idler is disclosed along with a method of molding the conveyor idler and the con-veyor idler apparatus. A vertical mold has specially shaped cavities for molding the idler without entrapping air, along with shafts positioning and support brackets at each end of the mold for molding a metal shaft into each end of the polymer idler. The shafts positioning and supporting brackets utilize the groove for the bearing retaining ring for locking each shaft into position.

Description

sack~round of the Inven-tion _ _ ~ . . .
The present invention relates to conveyor idlers and especially to an apparatus for molding an elongated, ~lexible, solid, polymer idler having metal shafts formed in each end, along with the process fox moldiny the idler and the idler apparatus molded by the process.
In the past, it has been common to provide troughing idlers for conveyor belts and these include flexible troughing idlers of the suspension type~ Flexible idlers of the suspension type have achieved commerical success as substitu-tes for previous conventional types of troughing idler having rigid rollers mounted on fixed axes. One such flexible troughin~ idler of the suspension type includes that illustrated in U.S. Patent No. 3,876,~90 which provides for an idler structure molded on a w:ire cable in which the wire cable is held to each end by two terminal bearings and in which the molded rollers are molded from neoprene. One disadvantage of this prior art idler is that it requires a great variety of mounts to fit each of many types of conveyor belts which require different vertical and horizontal adjustments of the outer ends of the idlers. The location of the supported ends of the idlers determine the curvature of the trough formed by the conveyor belt. Variations of the type of material to be conveyed frequently calls for various trough depths and curvatures. In installations usin~
previous conventional composite troughing idlers formed of individual rotatable rollers, adjustment of the outer ends of . the outer rolls was seldom provided for and any desired de~ree ol troughing was determined by the angularity of the axis of the end intermediate roller. Since the rollers have regid .~

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inflexlble axes, adjustment of the ends to vary troughing eurvatures :is a necessity on a radius determined by the roller length. With the adven-t of the flexible, suspension type troughing idlers, the adjustment of the suspension point became more feasible. In my prior U.S. Patent No. 3,033,352 ~or a Conveyor Idler Mounti~g Means and Support, I provided an adjustable support for the outer extremities of idler support rollers for conveyor belts of a flexible suspension type troughing idler which provided -for a lateral adjustment to be automatically affected as an incident to the vertical adjus-tment.
rrhese prior art ~lexible troughing idlers and mounts have worked satisEactorily for many years, but -the rise in the cost of the terminal materials has substantially increased the cost of suspension troughing idlers and their supporting systems. It is accordingly, one advantage of the present i~ventionto provide a mQlded conveyor idler which is easily formed of polymer materials for providing-the necessary strengh to support conveyor belts for long periods without failure.
In my prior U.S. Patent No. 4,011,938 for a Suspension Idler, I provide a conveyor idler and idler terminal bearing which has a one-piece, molded, elongated, flexible7 polymer idler having a plurality of rollers formed thereon. Each end of the idler has an enlarged portion which is engaged by terminal supports surrounding the enlarged portion to rotatably hold the idler in its mount~ The terminal supportsare made entirely of polymer materials, but may have a steeI pin mounted thereto for mounting to the conveyor idler mount. The present invention is an improvement over this prior U.S. Patent and provides a terminal connection of increased strength in a polymer idler, without using jrc~

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a cable or a chain, or the like, molded therein 'rhrough a pxocess that assures the ex~ct same length of each idl~ and avoids alignment problems and entrapped air during mol~ing in a process for making a conveyor idler.
Other typical flexible idler rollers havin~ a cable or chain center can be seen in U.S. Patent No. 3,~82,788 to Donadio, et al; and in U.S. Patent No. 3,182,787 to Lorenz; and other patents of interest may be seen in the U.S. an~ Eoreign patents cited as references in my prior U.S. Patent No. 4,011,938~
Molding of prior art suspension idlers is accomplished in a horizontal mold and requires tension on the cable in an atlemptio achieve concentricity of -the cable a~ molded idler.
Howeve.r, exact concentricity is not obtained an~ the idlers have small variations in length. It is accordingly, an aim of the present inven-tion to provide an elongated, ~lexible, suspension idler made of solid polymer material, such as a hiyh density polyurethane having end shaft members molded thereinto and a molding apparatus and molding process.
SumTnary of the Invention .. .. ....
A vertical mold apparatus for making a suspension idler has a base to support the mold and a vertical mold having a pair of hinged mold portions having a mold cavity fo.rmed therein. Upper and lower shaft positioning and support brackets are attached to one mold portion for supporting a shaft having an.anchor thereon protruding into said mold cavity during the molding operation, whereby the shaft becomes a portion of each molded suspension idler.
The mold cavity has a plurality of connecting shaft cavity portions with the roller cavity portions having an angle~ surface from the perimeter thexeof to the shaft cavi-ty portions to prevent entrap-ment of air in the vertical molding operation. The upper and J X C ~ 3 ~l~'73~
lower shaft positioning supports the shaft portion in the groove for the bearing retainer rings. The vertical mold has an over-flow opening to release air as liquid polymer is ~ed from the bottom of the vertical cavity and to indicate w~en the mold cavity is filled.
Also, a transparent tube allows visual observation of the shrinkage of the polymer to assure that the cavity is sufficiently filled. A method oE making a suspension idler from a molded polymer is also provided in which the vertical mold is made, the shafts are attached t~ the shaft positioning and support means in the bearing retainer ring groove and the shafts each having an anchor on one end protruding into the mold cavity.
The mold cavity is filled from the bottom of the vertically extending mold with a liquid polymer and the polymer cured. The idler is then removed from the molded suspension idler having the shafts protruding from each end.
The suspension idler has an elongated, flexible, solid, molded polymer idler member having a plurality of intermediate rollers formed thereon connected by spaced flexible shaft portions. The idler member has end rollers on each end havillg a shaft molded therein with each shaft having an anchor portion molded onto the end roller and a protruding portion having a bearing retainer ring groove. The solid, molded polymer idler has intermittent rollers being shaped with an angled side surface between the roller perimeter and the lntermediate shaft portion.
A preferred polymer is a high density polyurethane, while a pre-ferred shaft portion formed in the end of each roller is stain-less steel.

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Brief Description oE the Drawings Other objects, features and advantages of -the present inven-tion will be apparent from the written description and the drawings, in which:
Figure 1 is a side eleva-tion of a suspension idler mold in accordance with the present invention;
Figure 2 is a side elevation of the vertical ~old of Figure 1 open to show the mold cavities with the shafts in place;
Figure 3 is a sectional view of the vertical mold of Figures 1 and 2 filled with a liquid polymer;
Figure 4 is a sectional view taken on the line ~-~ of Fiyure 2;
Figure 5 is a partial sectional view of one suspension idler having a support bearing attached to the molded in shaft members;
Figure 6 is a sectional view taken on the line 6-6 of Figure 5; and Figure 7 is a side elevation of a suspension idl:er attached to a support and supporting belt thereon.
Figure 8 is a perspective view oE the second embodiment of a suspension idlex mold in accordance with the present invention;
Figure 9 is a partial elevation of -the mold of Figure 8 opened to show the mold cavities;
Figure 10 is a sectional view taken on the line 10-10 of Figure 9;
Figure 11 is a sectional view taken on the line 11-11 of Figure 10;
Figure 12 is a sectional view taken on the line 12-12 of Figure 8; and ~r~ `

Figure 13 is a sectional view ta~en thro~gh an idler in accordance wi-th the present invention showing -the shaft anchor formed therein.
Descrip~ion of the Preferred Embodiments . . _ . _ . .
Referring to Figures 1 through 4 of the drawings, a vertical mold 10 for ~lolding a suspension idler is illustrated having two halves 11 and 12 hinged together by hinge members 13.
The mold half 11 is attached to a base support 14 and has mold door latches 15 attached thereto for engaging latching brackets 16 attached to the mold half 12. The mold halves 11 and 12 operate together to form suspension idler cavities 17 for molding a suspension idler. The cavity 17 has a plurality of inter-mediate roller cavity portions'l8 connected -to each other by shaft cavity portions 20. Each roller cavity portion 18 has an angled surface 21 and 22 angling from each side of the perimeter of the roller cavity 18 to the intermediate shaft,cavity portion 20. The vertical mold 10 has an enlarged end roller cavity 23 at one end and an enlarged roller cavity 24 at the other end, which end portion has an outer end gurface 25 adjacent the ca~ity 23 and 26 adjacent the cavity 24. The cavities are provided with mold alignment pins 27. The vertical mold 10 has a shaEt opening 28 at the top side and a shaft opening 30 at the bottom side thereof, while the top side also has an overflow and air escape opening 30. An upper shaft positioning and support brac~et 13 is attached to the mold half 11 by nuts 32 and has grooves 33 with shaft support member 34 therein, which is 1, attached to an end shaft portion 35 in the bearing retainer ring groove 36 in the shaft 35. The opposite end of the shaft 3 has an anchor 37 formed thereon. Similarly, the opposite side jrc~

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of the mold 10 has a lower shaEt pos:itloning and support brac~et 3g att~ched to the mold portion 11 ancl having a shaft ~0 passing through an opening 30 .into the mold cavity portion 24 and supported by shaft support member ~1 connec-ted to the shaft with ~ixedly mounted in grooves ~2 in the bracket 3~ and a bearing retainer ring groove ~3 in the shaft 40. The shaft ~0 also has an anchor 44 formed on the end thereof and located in the cavity portion 24.
The mold cavi-ty 17 has a polymer input line 45 connected into the bottom of the vertica~l mold 10 to feed the polymer from the bottom of the cavity 17 to the top of the cavity which flow of polymer is controlled by cu-toff valve 46. The bearing retainer ring can also be attached to shafts 35 and 4G and used to support the shaft to shaft support brackets 31 and 38 without departing from the spirit and scope of the invention.
One preferred polymer is a high de~sity polyurethane.
The polymer is fed through the inlet pipe 45 until the cavity 17 is filled and the liquid polymer passes out the opening 30, at which time the valve 46 can be manually cut off. Once the polymer has cured, the mold can be opened as shown in Figure 2, and the extension idler removed. The shafts 35 are released by the opening of the mold so that the shaft 35 can be slid off shaft support member 33 and shaft ~0 slid off support member ~1.
The mold 10 advantageously allows for the filling of a polymer withou-t the entrapment of air by the ancJled surfaces 21 and 22, and by the filling of the mold from the bottom, thereby forcing air out the opposite end opening 30 as the mold cavity is filled with no place for the trapment of air during the molding. In addition, the shafts 35 and 40 are held in position by the same grooves which also serve to attach the suppor-t bearings to the jrc:~

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shaf-ts of the completed suspension idler. Supportiny the sha~s 35 and 40 in this manner in a vertical mold with the anchors 37 and 44 to prevent the loosening oE the sha~ts 35 and ~0 assures the suspension idler oE always the exact same len~Jth. The mold cavities 17 may be coated with a polytrifluorochloroethylene if desired, to assist in the removal of the cured suspension idler.
It should also be noted that a nylon string, or the like, can be connected through the mold and this directs the flow of the liquid polymer towards the strings and helps prevent the entrap-ment o~ air in a differently designed mold.
The process of making a suspension idler using the molding apparatus 10 involves making a molding apparatus as shown in Figures 1 through 4, making shaEt ends 35 and 40 as shown, then attaching the shafts 35 and 40 to the brackets 31 and 38 with the shaft support members 33 and ~1. The mold cavity 17 is filled ~rom the bottom upward through the line 45 until the liquid polymer overflows through the opening 30 and the molded suspension idler is cured and removed from the mold 10 and attached to a support bearing with the support bearing retainer rings. This vertical molding assures concentricity and the same length for each idler without resorting to tensioned steel or plaster cables or chains.
Turning now to Figures 5 through 7, a suspension idler in accordance with the present invention is illustrated having an elongated, flexible, polymer suspension idler member 50 having intermittent rollers 51 connected to intermittent shaft portions 52 and having an angled surface 53 between the perimeter of the rollers 51 and the shaft portions 52 and a wider end roller member 54 and 55 on each end. A support shaft 56 is mounted ~ 8 --jrc ~

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- in the end roller 54. Each suppor-t sha-E-t has an anchor 5~ formed thereon or welded thereto Eormed in the end por-tion 55 and protrud-, .:
ing therefrom and having an annular ~roove 60 in the end thereof for accep-ting the bearing retainer ring 59 for a-ttaching a bearing 62 to each end. The shape of the anchor 58 is more clearly illus-trated in Figure 6 as having a generally flat surface and having a plurality of notched portions 63 -therein formed in the ~;:
polymer body 50. The bearing retainer ring 59 is illustrated attached to the shaft 56 in Figure 4, and the ~longated flexible :
~; 10 polymer suspension idler 50 is illustrated in Figure 7, attached -to the idler mounting means 64 by fabricated s-tirrup-type bracke-ts 65 supporting bearings 62.
A coi-ltinuous endless txoughing bel-t 66 is shown riding :,.
` on the suspension idler 50 with the belt returnin~ underneath the suspension idler 50~ The suspension idler advantageously is produced wi-thout normal reinforcing cable or chain passing there-through and with polymers, such as a high ~e~sity polyurethane not normally used for suspension idlers because of the difficulty of molding the material with a center cable or chain. The idler can advantageously withstand the friction and wear on the end shafts by virtue of that portion being steel or a similar metal.
Turning now to Figures 8 through 12 of the drawings, ,~ another embodiment of mold in accordance with the present invention ` is illustrated for molding a suspension idler. The mold is the same as that illustrated in connection with Figures 1 through 3 having two halves 11 and 12 hinged together by hinge 13 and supported on a base support 14 and having mold door latches attached thereto for engaging la-tching bracke-ts 16 attached to the mold half 12. The mold halves 11 and 12 operate together to form suspension idler cavities 17 for molding a suspension ;

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idler. This mold includes improvements in -the upper shaft positioning of suppor-t bracket 31 attached to the mold half 11 by nuts 32 and has a shaEt support member 3~ therein. The plurality o~ shi.ms 78 are of predetermined thickness and are positioned beneath the shaft support member 34. The shims can be added or removed to precisely position the shaf-t 35 having the anchor 37 attached thereto in the molcl cavity 23.
The shaft support member 34 is held by threaded member 80 passing throuyh an aperture therein and locking onto the shims 78 when the threaded locking member 80 is screwed down in the threads in the opening in the bracket 31. This improve-ment in the support for the shaft 35 allows polymer suspension idlers to be an exact length-when the polymer cures, which is especially important since different polymers and even diff-erent batches of the same polymer will vary in shri,nkage during curing. The shafts 35 and 40 must be very precisely positioned to allow for the shrinkage. This is especially ir~portant because idlers must be of a precise length -to opera-te properly.
The threaded lock down m~mber 80 fitsthrough the aperture 82 which is slot shaped to allow positioning of the shaf~ support member 34, as shown by the arrows in Figure 10.
The present mold is also ,impro~ed by the addition of heater jacket 68 connected by heater wires 70 which are con-nected to heater controls 72 so that the heat can be maintained in a precise controlled pattern for the proper curin~ of the different polymers molded in the idler mold 10. A mold handle 74 is attached to the mold half 12 assists in opening the mold, as does a slot 76, formed therein for prying with a prying tool, such as a large screwdriver. The mold has a further improvement jrc:f ~

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in the use of a guide pin aperture 27 ~or accepting a guide pin 27. Guide pin 27 has a ~enerally cone shaped tip ko allow it to engage the aperture 27(a) an~ guide -the pin 27 khereinto for precisely aligning -the molds when the molds are closed.
It will, of course, be clear that more than one guide pin and guide pin aperture can be utilized with the molds ancl that the aperture can be cone shaped rather than the pin 27 if desired without departing from the spirit and scope of the invention.
As seen in Figure 12, the aperture 27(a) has a pin 27 therein in the closed mold. Pin 27 is press fitted into the mold half 11 and can be removed and replaced if it becomes sufficiently worn. This embodiment, like that of Figures 1 and 3, has a polymer input line 45 connected to a removable -Eilter tube or nipple 48 attached into the filter tube opening 47 and has a clamp cut off means 49 for blocking the line 45 when the mold cavities are filled. Similarly, the other end of the mold has a removable vent tube 29 inserted into the opening 30.
Fi~ure 13 shows a sectional view taken through molded idler 50 having an anchor 58 molded ~herein showiny a pair of openings 84 therethrouyh which, similar to the slots of ~he opening in Figure 6, allow passage of the fluid polymer around the anchor to firmly lock the anchor ln place.
It should be understood that the present invention is not to be construed as limited to the particular forms shown herein, which are to be considered illustrative rather than restrictive.

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Claims (16)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A vertical mold apparatus for molding a suspension idler, or the like comprising in combination:
a base;
a vertical mold having a pair of hinged mold portions having a mold cavity formed therein, one said mold portion being attached to said base;
an upper and lower shaft positioning and support means attached to one mold portion for supporting a shaft having an anchor formed on one end thereto and protruding into said mold cavity; and said mold cavity having a plurality of roller cavity portions connected by a plurality of connecting shaft cavity portions, said roller cavity portions having an angled surface from the perimeter thereof to said shaft cavity portions on either side thereof to prevent entrapment of air during vertical molding, whereby a suspension idler can be molded of a polymer without a cable therein.

2. A vertical mold in accordance with Claim 1, in which said upper and lower shaft positioning and support means includes a bracket on each end of said mold having a shaft support member adapted to support said shaft in the shaft bearing retainer ring annular groove.

3. A vertical mold in accordance with claim 2, in which an overflow opening connects the top portion of said vertical mold cavity to the atmosphere to allow the escape of air and to ascer-tain when said molding cavity is filled.

4. A vertical mold in accordance with Claim 3, in which said shaft openings in said vertical mold hold said shafts in position and release said shafts when said mold halves are opened.

5. A vertical mold in accordance with Claim 4, in which the cavities are polytrifluorochloroethylene coated.

6. A mold in accordance with Claim 5, in which said vertical mold cavities has an end roller cavity larger than the retaining roller cavities for providing additional strength to a molded suspension idler having a shaft with an anchor molded therein.

7. A mold apparatus for molding a suspension idler, or the like, comprising in combination:
a base;
a mold having a pair of hinged portions having a mold cavity formed therein, one said mold portion being attached to said base;
a pair of shaft positioning and support means attached to one mold portion for supporting a shaft having an anchor formed on one end thereof and protruding into said mold cavity from each end of said mold;
said mold cavity having a plurality of roller cavity portions connected by a plurality of connecting shaft cavity portions, said roller cavity portions having an angled surface from the perimeter thereof to said shaft cavity portions on either side thereof preventing entrapment of air during molding;
and means to vary the position of each end shaft to be supported in one end of said shaft positioning and support means, whereby said shafts can be positioned for shrinkage of different polymers to give a predetermined length in a suspension idler molded of a polymer without a cable therein.

8. A mold in accordance with Claim 7, in which said end shaft positioning and support means includes a bracket on each end of said mold having a shaft support member adapted to support said shaft in the shaft bearing retainer ring annular groove.

9. A mold in accordance with Claim 8, in which said means to vary the position of each end shaft includes shims of predeterm-ined thickness positioned adjacent said shaft support member to thereby space the shaft support member relative to the mold cavity, and said shaft support means and shims are locked in place with an attachment means.

10. A mold in accordance with Claim 9, in which said shaft support means is locked in place with an attachment means including a threaded member threaded to a knob and said threaded member passing through a slot in the bracket on each end of said mold for locking said shaft support means in position along said bracket slot.

11. A mold apparatus in accordance with Claim 7, in which one mold portion has at least one aperture therein positioned to receive a locking pin on the other said mold portion, whereby closing said mold halves will align the mold halves with said pin sliding into said opening.

12. A mold apparatus in accordance with Claim 11, in which said pin has a cone shaped end portion and is removably attached to said mold portion, whereby a worn pin can be replaced.

13. A mold apparatus in accordance with Claim 7, in which each said mold half has a heater jacket mounted thereon whereby the curing temperature of a polymer can be controlled in said mold.

14. A mold apparatus in accordance with Claim 7, in which at least one mold half has a prying slot formed therein for breaking said molds with a prying member in removing a molded idler.

15. A mold apparatus in accordance with Claim 7, in which one mold portion has an opening in each end thereof, whereby a a polymer can be injected in one end of said mold for filling said mold while air escapes from the opposite end.

16. A mold in accordance with Claim 15, in which the opening in each end of the mold has a removable sleeve mounted therein.