SPHCillCATlO

Field of the Invention

¾: present invention relates to casters that are use on carts, carriages and the like, which casters c n ride on grooved endless conveyors.

Background of the Invention

Endless conveyors are nse&l for moving people and items from place to place. An example of an aidless conveyor can be foun in some airports. The conveyors are fairly level. Some conveyors have grooves and are know as: travelators, walkalators, etc. These names derive front fesealatorT which is an endless conveyor t!iat forms stairs and typically goes between floors r levels in a building.

In addition to moving people the conveyors can also move items such as carts. The cards have casters so they can be easily rolled along the floor when they are located off of the conveyor. Retail stores: provide carts for the convenience of their customers, Customers put items for purchase in the carts and push the carts along as they shop, A retail store may have a grooved conveyor for customers an the carts, which conveyors can he horizontal or move between different floor levels of the store.

When a cart is located on the conveyor, for safety reasons, the cart should be relatively difficult to move. Each caster has a pair of thin wheels, which wheels fit into the grooves of the conveyor. A brake pad is located adjacent to the wheels, which pad hears on top of ^' the conveyor surface. The fitting of the wheels in the grooves and the contact of the brake pad whit the conveyor serve to inhibit motion of the cart relative to the conveyor. This arrangement allows a cart to be easily pushed onto and pushed off of the conveyor at the conveyor ends. The brake pad engage the conveyor only when the wheels are received by the grooves of the conveyor,

A problem with existing casters Is that the brake pads wear alter some usage. A worn brake pad presents a risk of Injury, as a cart not properly braked or secured on the inclined portion may move and hit somebody.

Maintenance crews; inspect casters for worn brake pads and replace as needed. However, t inspect the brake pads, the cart must be turned upside down to allow visual inspection of the brake: pads, This results in a loss of manpower. If a cart is turned Upside down, and the brake pads found to be satisfactory, the _· cart is returne to service. Such a lack of results in finding worn brake pads can produce frustration in those conducting a physically demanding inspection and can result in less frequent or less thorough inspections,

It is desirable to provide for an easier inspection of brake pads.

It is also desirable to allo tor easier replacement of brake pads in casters.

Summary of the Invention.

A caster U for use on grooved endless conveyor. The caster comprises wheels for engaging grooves of the grooved endless conveyor,

a a center member between the wheels, a brake pad located under the center me ber and between the wheels,’the brake ad is for contacting the grooved endless conveyor, The improvement: comprises a brake pad wea indicator, which comprises an indicator arm having first and secon ends and a pivot point, The second end is fixed in place relative to the brake pad when the brake pad is unworn. The first an second ends are capable of moving about the pivot point when the second end is no longer fixed in place relative to the brake pad, with the first end moving from a normal position to a release position. A channel Is located inside the center member, the channel having a first location and a second location, An indicator member is. located in the chann . A window is located in the center member and allows a view of the secon location, A retainer is in the channel for retaining the indicator member In the first locatio when the indicator arm first end is in the normal position. The retainer releases the Indicator member to move to the second location when the indicator arm first end is in the release position,

in one aspect, the indicator member is circular.

In another aspect, die indicator member has an outer circumference with a contrasting color from the center member.

I still another aspect, the indicator member moves fro the first location to the second location by gravity.

In still another aspect, the indicator arm second en is fixed in place relative to the brake pad when the brake pad is unworn by a spring.

I still another aspect, the indicator arm second end is located adjacent to the brake pad and, whe the brake pad is worn, the second end is moved by contact with the convey oh In still another aspect, the indicator ar second end is feed i place relative to the brake fad by a linkage with the brake pad, the linkage being sobfecf to wear as the brake pad wears.

In still another aspect, a spring moves die indicator ar first end iroin the normal position to the release position when: the linkage is broken.

Si still another aspect the caster thither comprises mounting structure for the brake pad. The mounting structure comprises a base adjacent to the brake pad and a tab extending from the base, The center member has a cavity for receiving the tab, A passage extends through the tab an the center member when the tab is received the cavity, L repovahle pin Is located in the passage.

In still a othe aspect, the mounting structure comprises plnral tabs and the center member has plum! cavities.

In still another aspect, the pin is threaded into the center member,

In still another aspect the pin Is secured i to the center member by an interference fit

Brief Description of the D a ings

Fig, 1 is a perspective view of a caster of the present invention, i accordance with a preferred embodiment, use on a groove conveyor.

Fig, 2 is a perspective view of the caste of Fig, 1 o a grooved conveyor, cut away to show the brake pad.

Fig, 3 Is perspective view of the caster, shown without: the yoke.

Fig 4 is a perspective view of the caster of Fig. 3, cut away to show the brake pad wear indicator Fig. 5 a perspective view of the indicator arm, showing the reverse side from what is shown in Fig. 4,

f ig. 6 shows the central member without the indicator arm.

fig. 7 a detail view of the lower end of the indicator arm and the brake pad, with the brake pad not exhibiting much wear.

Fig, 8 is the same view as hi Fig, 7, however with the brake pad exhibiting an amount of wear to cause actuation of the lever ami and make an indication,

Fig, 9 is die same view a Fig, !0 _> however, rhe indielo arm is being moved to actuate the indicator.

Figs 10 and 11 are exploded perspective views of the caster center member, and the indicato arm, in accordance with mother embodiment The indicator arm shown in the same reverse orientation as in Fig. 5.

Fig, 12 is a perspective cut away view of the caster of Fig. 10. sho wn with the brake pad with little or no wear,

Fig, 13 is a perspective dose tip 7ie of the caster of Fig. 12, shown with the retainer intact between the brake pad and the indicator arm.

Fig. 14 is a perspective cut away view of the caster o Fig. 10. shown wit the brake pad with significant wear and the indicator; arm releasing the- indicator to appear under the window.

Big. 13 is a perspective close ti view of the caster of Fig, 14, shown with the retainer worn away,

Fig, 16 is an ex loded perspective view of the replaceable brake pad arrangement,

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Figs, 1-2; show an example of a caster 11 that is designed ft both roll on a. typical floor surface and also ride on a grooved endless conveyor, The caster is used on a shopping cart, carriage, etc. The caster has two thin wheels 17 that are designed to fit into the grooves of a conveyor. Once the caster is located on the conveyor, with the thin wheels received by grooves in the conveyor, a brake pad 31 on the bottom of the caster contacts the top of the conveyor. The brake pad secures the caster from further movement along the conveyor. The brake pad is subject to wear from being in contact with the conveyor. The present invention provides an indicator feature tha shows when the brake pad is worn s to be replaced. Several embodimenis of the indicator feature are discussed.

The indicator feature provides an indicator tha is visible from the top of the caster. The indicator includes a window 73, if the brake pa is satisfactory, arid hot worn, the window 73 shows a clear or empty space, If the brake pad is worn, the space behind the window is filled, providing a visual indication, Thus, the wear state of the brake pad can be assessed with the cart in its normal operating position. The wear state of the brake pad can be assesse Without the need to directly view or measure the brake pad. The can need not be removed from service or turned upside down to assess the wear condition of the brake pad.

In addition, the brake pa Is part of a brake pa arrangement that allows for ea y replacement.

In the description herein, first the caster will he described, followed by a description of the brake pad indicator, in the description herein, terms such as 'Up er and‘lo er” may be used, which terms refer to the orientation of the caster shown in the drawings and in normal use. In addition, like reference numbers may be used across the casters, which reference numbers designate like components or parts.

Referring to Figs. 1-3, which shows the caster 1 with the brake indication feature, the caster 11 has two wheels 17, each of which is mounted to a respective huh 19. The hubs 19 are mounted to an axle 20 by way of a bearing. The axle is supported by a yoke 25, The caster 11 has an optional thread guard 27 on each side, between the yoke and the hub. The caster also has a back or rear side 32 (see Fig 3) and a front side. The back side 32 is the trailing side when the cart and the caster arc pushed forward The caster has a vertical kingpin 42. The kingpin is offset from the center of the !lee¾ this offset allows the caster to swivel and have the wheel trail behind the kingpin when the cart is pushe forward.

The two wheels 17 axe spaced apart from each other, with a center member 29 located between the wheels. The radius of the center member 29 is less than the radius of the wheels 17, so that the center member is located inside the caster and does not contact the floor or conveyor. The center member serves to space the wheels 17 apart the appropriate distance so as to fit in the grooves 30 of the conveyor, and to secure _: the brake ppd 3 L The brake pad is coupled to a support 55 (shown in lug. 5} that extends into the center member. The center member mounts on to the axle. The center member 2 is non-rotating with respect to the yoke 2S and the ground.

The center member 29 is provided with the brake pad 31 located in the lower portion ther of which brake pad contacts the upper surface of a grooved conveyor 33, The brake pa 31 is elevated so as to not contact a floor sm&ee whm the outer diameter of the wheels 17 contacts the floor. The center member 29 also has a stop 34 that contacts the yoke 25 and farther: assures that the center member does not rotate.

Man)·' of the components of the caster are made of plastic. For example, hie wheels 17 and the center member 29 are made of plastic. The axle and bearings are typically made of metal.

The wheels 17 contact the floor surface when the cart is not on the conveyor. The brake pad 3 1 is some distance above the floor surface, When the wheels contact the floor surface, the wheels bear the weight of the cart; the brake pad 31 does not contact the floor surface and does not bear any weight of the cart. However, when the caster is located in the conveyor grooves 30, the brake pad 31 contacts the conveyor an hears the weight o f th e cart

Referring to Figs, 3-7, the one embodiment of the . brake wea indicator feature will be described, The indicator feature includes a indicator arm 41* the center member 29, the brake pad 31 an an indicator 43.

The indicator arm 41 is shown in Figs, 5 and 6, The indicator arm 41 has a lower brake pad end 45 and m upper end 47. Hie arm is generall curved between the ends so as to be located Inside of the center member 29 The arm has a radial outside an a ra ial inside. The brake pa en 45 forms a foot* with a bottom surface 49 contacting a top surface 51 of the brake pad 31 (see Fig, 7). The brake pad end 45 also has a front side surface 53 that contacts the brake support 55, The brake support is discussed in more detail below. A pivot 57 is provided on the arm, a distance above the brake pad end 45, The pivot is, in the preferred embodiment, a cylindrical portion located on the radial inside of tire arm. The a also has a spring 59. In tile preferred embodiment, the spring extends; radially inward from. the main body of the atm, The upper end 47 of the arm forms a channel 61, or trough. The channel 61 is located on the radial outside of the arm and extends for a portion of the length of the ami. The channel has a hidden position 63 and an exposed position 64 The ar 41 need only form a bottom and a side of the channel as the center member 29 can form the other side and top of the channel As shown in Fig. 7, the side 71 has an indent 72 for the indicator 43, which indent forms part of foe channel. The channel 61 has ends rovide by the arm 41,

As shown in Fig. 8. the hottom suffece 49 of foe arm 41 can project slightly beyond (or below) the hralce pad support 55 (the brake pad 31 is not show in Fig 8 for clarity). Thus, some brake pad 31 may remain directly under the brake pad support 55, yet the indicator may still be actuated, Alternatively, foe bottom surface could be flush with foe bottom of the brake pad support, as shown in Fig. 8.

The center member 29 is modified t.o accommodate foe arm 41 The center member has a cavity 65 for receiving the arm. The cavity is located on the hack or rear side 32 of the axle 20. This allows foe indicator to he see on foe upper side of the caster ( when indicating a worn brake pad), without interference from the yoke. This also allows; the arm 41 to properly actuate when the brake pad wears. The cavity 65 is located between an outer wall 65, which Is curved to remain inside of the thin heels, and a center hub structure, The center hub structure surrounds the axle and has a circular wall 67. A portion of this circular Wall forms the cavity 63 , The center hub structure also has a downward extension 69 for receiving foe brake support 55. The downward extension is generally rectangular as seep in Fig. 5, with a cavity 58 for receiving the pivot 57 of foe arm. Side walls 71 arc also provided to enclose die cavity (in Fig, 4, one of the side walls is removed for viewing). The outer wall 65 has- an opening 74 therein. In the preferred embodiment the opening 74 is covere with a transparent member to form a window 73 , The window 73 is locate by the exposed position 64 in the channel 61. The outer wall has a boss 75, or projecting postion, above the window. The boss 75 projects into the channel 61,

The indicator 43 is a disc located in the channel hi. The indicator disc is able to travel freely along the length to the channel 61, unless otherwise obstructed. The indicator 43 is a contrasting color from the center member. For example; if the center member is gray, the indicator disc can b red. In the preierred embodiment, only the outside diameter of the disc is seen through the window and thus need be a contrasting color.

To assemble the brake indicator the arm 41 is located inside the cavity 63, with die lower end 45 in contact with the upper surface of the brake pa 31 , and the upper en 47 above the window 73. The indicator 43 is located in the upper part, or foe hidden position 63 , of foe channel and foe pivot 57 is pressed into its cavity 5S _¾ thereby securing the amt in place. With the arm installed, the indicator 43 & located above the boss 75 and out of vie of the window 73, The boss 75 thus holds or retains the indicator disc at the elevate and hidden position 63. The clearance between the boss 75 and the bottom of the channel 61 is less than the outer diameter of the indicator 43, thereby ensuring that foe indicator disc remains in place I foe hidden position. The spring 59 extends radially inward, with a fee end contacting foe wall 67 of the center hub structure. Tiie spring 59 biases the upper end 47 of the arm against the outer· waif thereby fother retaining the indicator disc in the hidden position.

The side is installed on the center member to enclose the arm. The remainder of the easier is assembled in accordance with prior art designs.

In use, the easier operates fey rolling on flat floor surfaces and engaging the grooves of a conveyor. When the cart is pushed onto a conveyor, the a t 41 is located on the rear or back; side 32 of the caster. When on a conveyor, the thin wheels 1.7 are located in the grooves an the brake pad 31 contacts the top surface of the conveyor, preventing further movement of the caster. At the end of the conveyor, the thin wheels are pushe out of the grooves fey the conveyor, lifting the brake pad and allowmg he casters to move. As shown in Fig, 7, the botom end 45 of the arm 41 is covered fey the brake pad 3 f and: is not moved fey the conveyor.

if the brake pa 31 is worn so as to expose the bottom end 45 of the arm: 41 (see Fig, 8) then as the cart ts pushed onto a conveyor, the top of the conveyor contacts the bottom end 45 of the arm. The conveyor exerts a rearward force on the botto end of the ami. This force overcomes the throe ofthe spring 59 and causes the arm to rotate slightly about the pivot 57 (see Fig. 9). The upper en 47 of he arm moves down and md lly inward, increasing the distance hetween the boss 75 and the bottom of the channel 61. The distance is great enough to allow the indicator 43 to fall font the elevated hidden position 63 to the lower exposed positron 64, Qravit pulls the disc down.

In tiie exposed position 64, the indicator 43 is at the bottom of the channel and can fee viewed through the window 73. Once the indicator disc is in the exposed position, it remains there. To m ve the disc back to tiie hidden position requires the arm to pivot and the disc to move up against gravity, the combination of which is unlikely.

When the cart leaves the conveyor the spring returns the lever arm io its original position, effectively closing the upper part of the channel to the indicator disc and serving to retain the disc in the exposed position.

Maintenance personnel inspect the casters for brake pad wear by looking at the window 73 each caster if the window is clear, with no disc, then the ad still has useful life. However, if the win ow' shows the indicator disc, then the brake pad is worn and should be replaced. The cart can be removed from service and the easier worked on to re lace the brake pa and its support 55, When the brake pad is replace , the indicator is reset to move the indicator 43 to the hidden position 63 The indicator can be reused with the easier, with only the brake pad 31 and its support 55 needing replacement

Thus, the carts and casters can be checked periodically for brake pad wear. _: Such an inspection can occur while; the carts arc in service The carts need not be upended or turned over,

Figs. 10-15 show another embodiment of the caster.

The indicator 43 can he solid or ring-shaped;, as shown in Fig. 11. The outer diameter is colored red or some other contrasting color.

The indicator arm 41 is located in the center member 29, _: The indicator ar 29 has a cylindrical projection 57 that is received by a. cavity 58 in the center member 29. The projection 57 and cavity So fern a pivot point for the indicator arm 41 ,

The upper end of the indicator arm 41 forms the channel 6.1 , together with the center membe side 71, which has an indent 72 for the indicator 43. The channel 61 Is also formed by a cover plate (not shown). The indicator i 41 is located between tie site 71 and the cover plate. The cove plate also retains the indicator arm 41 in place while allowing the indicator arm to pivot about tile pivot point.

The lower end 45 of the ind icator arm has a cavity 79 for receiving a brats pad linkage 81 The brake pad linkage 81 extends fronrthe brake pad 3.1 in a direction that is generally circumferential to the center member once the brake pad is installed, The fee end; 83 of t he linkage is enlarged and is located within the cavity 79.

The brake pad linkage 81 , when coupled to the brake pa 31 and the indicator arm 41,: prevents the indicator arm fern pivoting, thereby retaining the indicator 43 in the hidden posit i on 63

A .helical spring 85 is provided, which spring pushes between the lower en 45 of the indicator arm 41 an the central structure of the center member 2 , The ends of the spring are received i respective cavities 87, 89 i the indicator arm and the center memher.

The brake pa linkage 81 is integral to and coupled to an end of the brake pad 31. As the brake pad wears, so too does the coupling of the linkage with the brake pad.

In operation, the indicator 43 is kept hidden by the indicator ami 4L As the brake pad 31 wears, eventually the pa will wear sufficiently that the linkage 81 will no longer be coupled to the brake pad (see Figs. 14- 15), In other words, the coupling of the linkage to the brake pad is locate so as to wear, or erode, at the same rate as the brake pad itself When the linkage 81 is fee of die brake pad, if no longer holds the indicator ami and the spring 85 forces the indicate arm 41 to pivot. This opens the channel 61 and allows the indicator 43 to fail to the expose position _* where it can he seen throug the window 73. Once the indicator is in the exposed position _* Jt remains there due to gravity .

The brake pad 31 and brake pad linkage 8 ! are part of a brake pa arrangement. The brake pad arrangement has mounting structure for mounting the brake pad to the center member. In the embodiment shown, the mounting structure has a support or base §5 and upwardly extending tabs 91 that extend from the base (see Fig. lb). The tabs 91 are received by cavities; 93 in the bottom of the center member 29.

The brake pad arrangement is made to be easily installed and replaced. The tabs 91 and the center member 29 have openings that align to form a passage 95 when the brake pad arrangement; is installed in the center member. A pin 97 is inserted into the passage to retain the brake fad arrangement. The pin can be secured i several ways. One way Is to provide threads 99 on me pin an the center member passage. Another wa is to make an interferenee fit between the pi 97 Mid the passage 95 ,

To assemble the center member of the caster _* the indicator disc is located in the indent 72, the spring in located in the indicator arm and the indicator arm is mounted therein and tested for pivoting action, The brake pad arrangement is positioned and the projection free end is locate in the lower end of the indicator arm. The brake pad arrangement is inserted into the center member and retained by inserting the pi into the passage. If the pin is threaded _* the pin is rotated until secure. The cover plate is placed in position and ultrasonicaliy welded in place. The center member ca he incorporated into the caster,

To replace the brake pad _* the cart need not be completely turned over _* but merely tipped to one side so as to allow access to the bottom of the caster. The _. pin is removed, either by unscrewing or pulling. Once removed, the brake pad arrangement can be removed and replaced Hi© installation process for the replaeemcnt brake pad is as describeci abo e, The foregoing disclosure and showings made in the drawings are merely illustrative of the principles of this invention and are not to he interpreted in a limiting sense.

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