MXPA00011993A - Blow molded wheel with axle retainer - Google Patents

Abstract

A blow-molded wheel including an axle retainer assembly. The retainer assembly (31) includes a housing (42) having transverse sleeves that support an axle (14) and a spring biased retainer pin (10) that mounts to an annular groove (12) at the axle. The housing is supported in a cavity formed into a wheel spoke (18) and a bore of a wheel hub and is retarined upon the shrinkage of the plastic around the housing. An aperture of the pin sleeve facilitates retraction of the pin and release of the wheel from the axle.

Description

MOLDED WHEEL BY BLOWING WITH AXLE RETAIN RELATED APPLICATIONS This is a continuation in part of the United States of America patent application 09 / 090,618 filed on June 4, 1998.

BACKGROUND OF THE INVENTION The present invention relates to plastic wheels and in particular, to a blow molded wheel having a spring-deflected shaft seal and a fitted race. The varieties of pneumatic and compound wheels have been developed to include integral shaft seals. Some available composite wheels include an injection molded mass that supports a molded rubber tread on a rim with flanges. The rolling element is joined separately to the mass as by extension. A spring-biased pin is deflected into the mass and the pin projects into the bore of an axle support. With the union of the wheel to an axle having an annular coupling recess, the pin is compressed and expanded into the recess to permanently secure the wheel to the axle. The pin is not otherwise exposed to facilitate separation of the wheel. The entire plastic wheel can provide a cost-effective alternative. However, the entire plastic wheel is generally not available to include an integral retainer. A blow molded wheel including a retainer is shown in U.S. Patent 5,368,371. The retainer consists of annular tabs which extend into an axle hole and which are mounted to a slotted recess in a coupling shaft. The strength of the tabs can limit the type of application to which such wheels are placed. The tabs are also prone to damage if the wheels are removed. The present invention was developed to provide an improved blow molded plastic wheel having an integral shaft seal. The wheel provides an externally accessible spring-diverted detent pin that is inserted into a blow molded wheel. The detent pin can be mounted in a discrete housing that is adjusted to the wheel or an amount formed within the wheel. In a preferred construction, the detent pin projects radially from a pin retainer sleeve that is fitted to an axle sleeve. A hole and a cavity adjacent to the wheels support the shaft sleeve to provide a load bearing surface for the shaft and align the pin to the shaft. The wheel also includes a running surface that can be molded as part of the wheel or that can be separately joined to the wheel. BRIEF DESCRIPTION OF THE INVENTION Accordingly, it is a principal object of the invention to provide a blow molded wheel with a integral shaft seal. It is a further object of the invention to provide a wheel having an axle detent that is indexed to a separately molded wheel and includes a pin and axle sleeve that extend transverse to each other. It is a further object of the invention to provide a wheel with an axle retainer pin that can be released from the axle after assembly. It is a further object of the invention to provide a retainer that can be mounted to the wheel prior to final curing. Several of the objects, advantages and prior identities of the invention are obtained in the blow molded wheel of the present preferred. The wheel is blow molded in a conventional manner and includes a cavity in one of the spokes that is formed to accept a spring biased retainer. The cavity opens towards an axle hole in the wheel. The retainer is fixed within the cavity immediately on the wheel that is removed from the mold, while the plastic is hot. The plastic shrinks around the retainer as it cools and permanently secures the retainer to the wheel. The retainer includes a sleeve of pin that supports a spring inside a longitudinal hole. The spring biases the detent pin to project into a longitudinal hole in an axle sleeve. The shaft sleeve is mounted concentrically inside the shaft hole. The hole in the shaft sleeve acts as a bearing and provides a load bearing surface for the shaft. The hole in the shaft sleeve extends transverse to the hole in the pin sleeve. An opening is provided through the walls of the pin sleeve to allow the release of the pin from the shaft. Other objects, advantages, distinctive and constructions of the invention will become even more evident from the following description with respect to the attached drawings. The components and similar assemblies are referred to in the different drawings with similar alphanumeric reference characters. The description should not be considered literally limiting the invention. Instead, the invention should be construed within the broad scope of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view shown in an exploded assembly for a wheel constructed with a releasable shaft retainer assembly. Figure 2 is a perspective view shown in partial cut-out for a blow molded wheel having a rolling part mounted on the wheel and equipped with a shaft retainer assembly.

Figure 3 is a partial sectional view through the shaft and the retainer of Figure 1, when assembled together Figure 4 is a front view of the retainer Figure 5 is a rear view of the retainer Figure 6 is a rear view of the retainer wherein the outer surface is formed to improve attachment to the blow molded wheel Figure 7 is a front view of a blow molded wheel and a retainer assembly shown in broken assembly Figure 8 is a rear view of the blow molded wheel of Figure 7 Figure 9 is a front view of a blow molded wheel and wherein a retainer assembly is formed to extend from the rolling support surface. Figure 10 is a rear view of a molded wheel by blowing of Figure 9 Figure 11 is a front view of a blow molded wheel and wherein a retainer assembly is formed to extend from the rolling support surface. Figure 12 is a rear view of the blow molded wheel of Figure 9 Figure 13 is a front view of a blow molded wheel and wherein a retaining sleeve extends from a raised web which is located parallel to a plane in the line of partition of the wheel and with a slot in the box. Figure 14 is a rear view of the blow molded wheel of Figure 13. Figure 15 is a front view of the blow molded wheel and wherein a detent sleeve having a two-step orifice extends from a web elevated that is located parallel to a plane in the line of partition of the wheel. Figure 16 is a rear view of the blow molded wheel of Figure 15. Figure 17 is a front view of a blow molded wheel and wherein a detent sleeve having a two-stage orifice extends from a raised frame that is located parallel to a plane in the partition line in the wheel and between adjacent interrupted rays. Figure 18 is a rear view of the blow molded wheel of Figure 17. Figure 19 is a front view of a blow molded wheel and wherein a detent sleeve is formed to extend from the mass at an acute angle with relation to a plane in the line of partition of the wheel. Figure 20 is a rear view of the blow molded wheel of Figure 19. Figure 21 is a front view of a blow molded wheel and wherein a detent sleeve is formed to extend at an acute angle relative to a plane on the parting line of the wheel from a platform raised in the frame. Figure 22 is a rear view of the blow molded wheel of Figure 21. Figure 23 is a cross-sectional view through a wheel having a raised partition line that mounts to a groove aligned in one piece of rolling coupling.

DESCRIPTION OF THE PREFERRED MODE Referring to Figures 1, 2 and 3 the views are shown for improved wheels 2, and 3 which are adjusted with a shaft seal assembly 4. Wheels 2 and 3 are constructed from wheels of blow molded plastic 6 and 7. The wheels 6 and 7 each include cavity 8 that receives a shaft retainer assembly 4. A double ended pin 10 of the assembly 4 is aligned with, and mounted to, an annular groove 12. of an axle 14, refer to Figure 3. Wheels 6 and 7 are blow molded in a conventional manner and provide a mass 16 and from which a number of rays 18 and intermediate planar frames 19 radiate towards a box or ring rim 20. Wheel 6 includes a number of grooves with tabs 22. The. Rolls 22 are molded on a surface 24 that couples the ground A raised strip 26 projects around the circumference of the wheel 6 and on the treads 22 in the center of the tread surface 24. A line ... * m-.i ** p & k hi * wm &«m-r. of separation defined by the molding operation extends around the center of the strip 26. An accessory ornament piece, or white band tire 28 may be attached to an annular groove 30 that is formed within one or both of the exposed sidewall faces of the box 20. The blow molded wheel 3 of Figure 2 is substantially the same as the wheel 2, except that a separate molded raceway 5 is mounted to the box 20. A uniform, recessed surface 7 of the box 20 includes a flange 9 and to which the running piece 5 is aligned. The running piece 5 is molded from ethylene methyl acrylate copolymer (EMA) although an EEA, EVA or LLDPE material among other materials can be used. A rolling number with tongues 11 is molded into the running piece 5. The running piece 5 is adjusted by stretching on the wheel 7 while it is hot. The density of the tread piece 5 is selected to provide a durable surface. The rolling part 5 also minimizes the rolling sounds of the wheel 3 on certain surfaces and whose sounds can otherwise be amplified due to the hollow cavity in the wheel 3. Returning to Figure 1, the cavity 8 is molded Within one of the spokes 18. The cavity 8 opens at one end into the shaft bore 29. An opposite end provides a closed wall 33. A housing 31 of the assembly 4 includes a pin sleeve 32 which mounts inside the cavity 8. The pin 10 is supported within a hole 34 of the pin sleeve 32 and is biased to allow alternating movement in conjunction with a spring 36. The pin 10 projects through an opening 38 in the hole 34, referring to the Figure 3, and within a longitudinal hole 40 of a shaft sleeve 42 extending transverse to the pin sleeve 32. The spring 36 butts one end of the recess 33 in the open end of the pin sleeve 32. orifice 40 accepts the shaft 14 separately. The hole 40 provides a load bearing surface for the shaft 14. A cover 46 closes the end of the housing 31 and the hole 40. The housing 31 is retained to the wheel 6 in the sleeves of pin and shaft 32 and 42. The transverse orientation of the pin and shaft sleeves 32 and 42 between each other, ensures that the retainer assembly 4 does not loosen and rotate with the wheel 6. The retainer housing 31 can be attached to the wheel. Currently, it is ensured through the contraction of the wheel material. If required, the retention can be improved by forming the outer walls of the retainer to include molded shapes such as described below in relation to Figures 6 and 7. With further attention to Figures 3 and 4, an opening 48 extends through of a side wall of the axle sleeve 32 and is exposed to the wheel 6 to allow access to the pin 10. By inserting a tool through the opening 48, a shoulder 47 of the pin 10 can be engaged and the pin 10 it can be depressed to release one of the pair of ends 49 from the shaft 14. The opening 48 can be subjected to a spark gap as in Figure 2, when the molding of the housing 31 prevents casual access to the pin 10. Depending on the application , wheels 6 and 7 can be molded from a variety of plastic types. The type of plastic and the density of the material can be varied for a particular application and the load and wear specifications for a particular wheel. The configuration and size of wheels 6 and 7 can also vary. The wheels 6 and 7 are currently molded from a high density polyethylene material and each is constructed to a diameter of 30.48 cm. A variety of other known materials can be used for an equal advantage. The retainer housing 31 is molded from a material that is compatible with the wheel material. An HDPE material is currently used. Nevertheless, depending on the application in the housing 31, a variety of other materials including various metals and plastics can be constructed. The pin 10 is constructed from the metal. Various other metals may be used provided they are able to withstand anticipated wear on the shaft 14. After removing the wheel 6 from its mold and while the plastic is hot, the retainer assembly 4 is fitted to the cavity 8 and to the hole 31. As the wheel 6 cools, the material contracts around the axle sleeves 32 and 42 to permanently mount the retainer assembly 4 to the wheel 6. Although not currently required, retention can be improved by shaping of the outer surfaces of the sleeves 32 and 42 to hold the coupling surfaces of the wheels 6 and 7. For example, and with further attention to Figure 6, a flat surface 50 and / or raised projections 52 and / or one or more recesses can be provided. Currently, a recessed slot 54 is included. The groove 54 assists separately in the withdrawal of the retainer housing 31 from an injection mold. The raised projections 52 can be formed as annular ribs or ribs. Figures 7 and 8 illustrate a front and rear view for a wheel 60 that is fitted with a detent housing 62. The housing 62 supports a detent pin and a spring in a pin sleeve 63 in a similar fashion to the assembly retainer 4. A hole 65 (shown in dashed line) through an axle sleeve 67 supports an axle 14. A slot 64 extends around the outside of the housing 62. Shaped separately inside the housing 62 is a slot 66 and a raised projection 68 extending approximately halfway around the circumference of housing 62. A raised band 70 which may or may not be included and which may have a rounded exposed surface, similar to an O-ring, or a wedge, is also shown in dotted line. or ramp shape. Proper provision of the outer surface of the housing 62 with slots 64, 66 and / or projections 68 and 70 facilitates retention of the housing in the wheel 60. Figures 9 to 12 show the wheels 90 and 92 that are molded with retainer sleeves. integral 94 and 96. Such construction avoids the need to adjust a separate detent housing to a finished wheel. However, the sleeves require additional plastic and can increase the complexity of the mold and / or the difficulty of molding. The sleeves 94 and 96 extend from the mass 16 to the casing 20 of the wheels 90 and 92 along the frames 98 and 100. The frames 98 and 100 are vertically offset from the other frames 19. The sleeve 96 exhibits a outer diameter greater than sleeve 94 and tapers in slightly as it extends from box 20. Sleeves 94 and 96 include longitudinal holes 95 and 97 that receive an appropriate spring and catch pin. The holes 95 and 97 are accessed by drilling aligned holes 101 and 103 through the perimeter of the box 20 and the dough 16. The drilling operation is typically performed after the casting of the wheels 90 and 92. The rolling stock 5 and / or a plug (not shown) cover and / or fill the holes 101 and 103. Figures 13 to 18 illustrate front and rear views of the wheels 102, 104 and 106 including the detent sleeves 108, 110 and 112 that are molded to prevent holes from being drilled through the box 20 to facilitate assembly i: on an axle and / or spring retainer pin. The detent sleeves 108, 110 and 112 are molded in frames 114, 116 and 118 which are raised over the frames 19 between the other spokes 18. The elevation of the frames 114, 116 and 118 is determined in relation to the operations required drilling. The frame 118 also includes a slight recess 119 which is visible in Figure 18. The aligned slots 120, 122, and 124 are molded in the casing 20 of the wheels 102, 104 and 106, to facilitate the formation of holes 126, 128 and 130 of the detent sleeves 108, 110 and 112. The slots 120, 122 and 124 are shown exposed although usually substantially covered by the raceway 15. The holes 128 and 130 are formed with two different internal diameters which define an internal shoulder that limits the movement of the detent pin. Upon adjustment of a suitable detent pin and deflection spring mechanism within the detent sleeves 94, 96, 108, 110 and 112, an end cap is secured to the sleeves. A threaded end cap is normally used, although a variety of other plugs can be replaced, provided that they securely retain the detent pin in the pin sleeve. Two alternative wheels 132, and 134 are shown in Figures 19 to 22. The wheels 132 and 134 include detent sleeves 136 and 138 extending at acute angles relative to a plane containing the separation line of each wheel. The sleeves extend along the wefts 140 and 142. Weft 140 extends from the mass 16 at a continuous inclination. The weft 142, in comparison, provides an elevated inner portion 144 which is raised on an outer portion 1? 6. The holes 148 and 150 extend through the sleeves 136 and 138. Upon perforation of the sleeves, the appropriate detent pins and springs are adjusted, a threaded end cap 152 is secured to each sleeve. Figure 23 finally illustrates a cross-sectional view for mounting an alternative race 160 to a blow-molded wheel 162. The wheel 162 is essentially similar to wheel 3, except that it includes a raised projection 164 in the line of separation of the wheel 162. The wheel 162 can be adapted to include any of the above shaft seals or not, as desired. The projection 162 mounts within a groove 166 molded into the race 160. The engagement of the groove 166 with the projection 164 stabilizes the race 160 against lateral sliding and minimizes possible rolling separation. In most cases, the annular flaps 9 are sufficient to prevent rolling separation. Although an individual continuous projection 162 is shown, multiple adjacent projections 162 may be provided at the periphery of the blow molded wheel 162. The projections 162 may also be constructed to be discontinuous. The projections may exhibit a rounded, ramp or other contour shape when viewed in side profile, such as in projections 52 and 68. While the invention has been described with respect to a preferred construction and the improvements considered alternatives to the same, to other constructions can be suggested by those with experience in the art. Although certain characteristics are shown on particular wheels, it should be appreciated that the features may be included alone or in other combinations on some other wheels described. The above description should therefore be considered to include all modalities within the spirit and scope of the appended claims. í. ^ Afói

Claims (8)

1. CLAIMS 1. A molded plastic wheel adapted to be mounted to an axle, comprising: a) an annular body having a hole that receives the shaft and includes a rolling surface, wherein a plurality of spokes are positioned radially between the hole and the rolling surface and wherein one of such spokes includes a recessed cavity communicating with the hole; and b) retainer means mounted in the cavity to secure the wheel to the shaft and wherein a detent housing includes a) a pin mounted to project from the housing and 2) means for deflecting the pin for reciprocating movement relative to the housing and for coupling to the shaft. A wheel as set forth in claim 1, characterized in that the wheel is blow molded and wherein the detent housing includes a tubular pin sleeve containing the pin and the spring biasing the pin to project into the hole. A wheel according to claim 2, characterized in that the retainer housing includes a tubular shaft sleeve extending transverse to the pin sleeve, wherein the shaft sleeve mounts in the hole and where the pin projects to through an opening that communicates with an axis hole of the shaft sleeve. 4. A wheel according to claim 3, characterized in that an opening in the pin sleeve is exposed on the wheel to allow access to the pin, whereby the pin can be manipulated to separate the wheel from the axle. 5. A wheel according to claim 3, characterized in that an external surface of the retainer housing includes a plurality of raised projections. 6. A wheel according to claim 3, characterized in that an external surface of the retainer housing includes a plurality of recesses. A wheel according to claim 3, characterized in that an external surface of the retainer housing includes at least one flat surface. 8. A wheel according to claim 1, characterized in that the retainer housing includes a tubular pin sleeve containing the pin and a spring that biases the pin for reciprocating movement, wherein a tubular shaft sleeve extends transverse to the sleeve. of the pin, wherein the sleeve of the shaft is mounted in the hole and wherein the pin projects through an opening communicating with an axis hole of the shaft sleeve and wherein an opening in the pin sleeve is exposed to allow access to the pin, so that the pin can be manipulated to separate the wheel from the shaft. íe A wheel according to claim 1, characterized in that the separately molded race is mounted to the body. 10. A molded plastic wheel, adapted to be mounted to an axle, comprising: a) a blow molded wheel having a hole and a rolling surface, wherein a recessed cavity is placed between the hole and the running surface communicating with the hole; and b) retainer means for securing the wheel to the shaft including a pin and means for biasing the pin for reciprocating movement within the wheel and for projecting into the hole for engagement with the shaft. A wheel according to claim 10, characterized in that the housing is mounted to the cavity that includes a tubular pin sleeve containing the pin and a spring that deflects the pin, wherein a tubular shaft sleeve extends transverse to the pin. pin sleeve, wherein the shaft sleeve is mounted in the hole and wherein the pin projects through an opening communicating with a shaft bore of the shaft sleeve. 12. A wheel according to claim 11, characterized in that an opening in the pin sleeve is exposed in the wheel to allow access to the pin., so the pin can be manipulated to separate the wheel from the shaft. A wheel according to claim 11, characterized in that the external surfaces of the housing include means for joining the housing to the cavity. A method for constructing a self-locking wheel comprising: a) blow molding a wheel having a hole and a threaded surface and wherein a recessed cavity is placed between the hole and a threaded surface communicating with the hole; b) removing the wheel from a mold and, while the wheel is hot, adjusting a detent housing to the cavity including a pin and means for biasing the pin for reciprocating movement to project into the hole and to engage the shaft; and c) allowing the wheel to cool and the plastic material to contract around the retainer housing to secure the detent housing to the wheel. 15. A molded plastic wheel adapted to be mounted to an axle, comprising: a) an annular body having an axle hole and including a rolling surface and wherein a plurality of spokes extend radially between the hole of axis and running surface; Y and b ^^^ ^ tiigXm ^ M ^? ^^^ sb b) a detent housing mounted to the body to define the shaft bore and wherein a pin is mounted to project from the detent housing into the shaft bore. A wheel according to claim 15 characterized in that the wheel is blow molded and the body includes a plurality of hollow cavities, wherein the detent housing includes a first hole defining an axis hole, and wherein the housing catch includes a second hole extending transverse to the first hole and supporting the pin and a spring mounted to bias the pin for reciprocating movement relative to the first hole. A wheel according to claim 16 characterized in that the retainer housing comprises a sleeve with a cylindrical shaft and through which the first orifice extends and wherein the second orifice extends orthogonal to said first orifice. A wheel according to claim 15, characterized in that the body includes a mass from which the rays arise, wherein the retainer housing comprises a tubular shaft sleeve having a first hole defining the shaft orifice, and wherein the detent housing includes a second hole extending transverse to the first hole and supporting the pin and a spring mounted to bias the pin for reciprocating movement relative to the first hole. A wheel according to claim 15, characterized in that the bearing surface is defined by a separately molded race that is mounted to the body. 20. A molded plastic wheel adapted to be mounted to an axle, comprising an annular body which is blow molded from a first material and which includes a plurality of hollow cavities, a mass having an axle hole, and a plurality of spokes extending radially from the mass to a box, and wherein a rolling piece that is separately molded from a second material having a different density from the first material is mounted on the box to define a surface of tread.