Caster with universal mount and swivel and wheel lock

[0002] Swiveling caster assemblies are well known and widely used. Some such caster assemblies have devices to lock the caster wheel, when desired, to prevent inadvertent rolling movement after the supported object has been parked in a desired location. Some of them also have devices to disable the swivel feature to prevent swiveling of the caster relative to the object when the object is parked. Some have a combination of swivel lock and wheel lock features.

[0003] Swiveling casters are also provided with various arrangements for mounting to the object to be supported. One type of mount that is widely used is a plate having holes through it to receive fasteners for attaching it to the bottom of the object to be supported. A bearing structure is provided between the plate and the caster horn. Another type of mount is a stem fastened to the caster horn and projecting upward from the caster horn and received in a downwardly opening socket in the object supported. One version of this approach has a resilient metal split ring received in a groove in the stem and engaging a wall of the socket and frictionally retaining the stem in the socket. But there is sufficient space between the ring and the groove for the stem to rotate in the socket and enable the stem, and thereby the caster, to swivel in the socket. Another type of mount is a threaded stem which is screwed into a socket in the object to be supported and which has features at the lower end for reception in a socket in the caster horn or for mounting through a ball bearing assembly to the caster horn.

[0004] In addition to the above-mentioned possibilities for various combinations of features, aesthetic considerations have increasing importance for some markets. Color variety and avoidance of appearance-compromising rust and tarnish have led to adoption of plastics in some instances. Customers can require certain colors.

[0005] It occurs to us that, because of the wide variety of features and combinations of features that customers of caster manufacturers might want, it would be desirable to have a basic caster assembly which is easily adapted to various customer requirements. The present invention is addressed to assisting a caster manufacturer to successfully address one or more of the aforementioned possible customer desires.

[0006] Described briefly, according to a typical embodiment of the present invention, a caster assembly is provided with a caster horn with an upwardly opening special receiver therein configured to receive a special stem configured according to the invention for mounting to various types of objects to be supported by such casters. Various mounting devices are provided, all of them with the special stem for reception in the special receiver. One embodiment of mounting device is a plate having the special stem embedded in it and projecting downward from it. Another embodiment is an upward projection from the special stem and which has a groove with a split ring for snap-in connection into a socket in the object to be supported. Another embodiment is an upward projection of the special stem and which is threaded to be screwed into a socket in an object to be supported. The special stem and receiver have a cooperating snap-in feature whereby the stem is retained in the receiver of the horn, once installed with the horn.

[0007] The horn according to the invention has a slot for reception of either a snap-in cover if there is to be no lock assembly, or for installation of a brake operating lever if the caster assembly is to have a wheel lock, a swivel lock, or a combination of wheel and swivel lock. The caster horn and either the cover or the brake operating lever, as the case may be, are made of molded plastic.

[0008] FIG. 1 is an exploded perspective view of a caster assembly according to one embodiment of the present invention.

[0009] FIG. 2 is a rear elevational view thereof.

[0010] FIG. 3 is a section (except for the wheel) taken at line 3—3 in FIG. 2 and viewed in the direction of the arrows.

[0011] FIG. 4 is a side elevational view taken at line 4—4 in FIG. 2 and viewed in the direction of the arrows, with a portion broken away to show the wheel brake operating lever and swivel lock engaged.

[0012] FIG. 5 is a top plan view of the horn portion thereof.

[0013] FIG. 6 is a side elevational view of the horn portion with a portion of one horn leg broken away to show interior features.

[0014] FIG. 7 is a bottom plan view thereof.

[0015] FIG. 8 is a bottom plan view of the top plate of the embodiment shown in FIGS. 1-3.

[0016] FIG. 9 is a side elevational view of the brake operating lever.

[0017] FIG. 10 is a front elevational view thereof.

[0018] FIG. 11 is a rear elevational view thereof.

[0019] FIG. 12 is a bottom perspective view thereof.

[0020] FIG. 13 is a top plan view thereof.

[0021] FIG. 14 is a top plan view of the lock spring.

[0022] FIG. 15 is a side elevational view thereof.

[0023] FIG. 16 is a view of the same type as FIG. 2, but showing another embodiment of the caster assembly using a smooth stem with a groove receiving a split ring for swivel connection to the object being supported by the caster assembly, and including the wheel lock but not the swivel lock.

[0024] FIG. 17 is a sectional view like FIG. 3, but for the FIG. 17 embodiment.

[0025] FIG. 18 is a rear elevational view of another embodiment similar to FIG. 2 but omitting the wheel lock and swivel lock features, and incorporating a snap-on cover in place of the brake operating lever of FIG. 2.

[0026] FIG. 19 is a section through the caster assembly taken at line 19—19 in FIG. 18 and viewed in the direction of the arrows.

[0027] FIG. 20 is a top view of a snap-on cover used in place of the brake operating lever in the casters such as shown in FIGS. 18, 19, 23 and 24.

[0028] FIG. 21 is a rear view of the snap-on cover.

[0029] FIG. 22 is a side view of the snap cover.

[0030] FIG. 23 is a rear elevational view of another embodiment of the invention like that of FIG. 16 but incorporating a threaded swivel stem and omitting the wheel lock and swivel lock.

[0031] FIG. 24 is a section through the caster assembly of FIG. 23 taken along the lines 24—24 in FIG. 23 and viewed in the direction of the arrows.

[0032] For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

[0033] Referring first to FIGS. 1-3, the illustrated caster assembly includes a wheel assembly 11 including a core portion 12 and tread portion 13. This is received in a horn 14 which, in the illustrated embodiment, has a top 16 and two horizontally spaced legs 17 and 18. In the illustrated embodiments, the top has a portion which bridges the space between the legs and steps downward to a portion 19, having a rear edge 21 located forward of the rear edges 17R and 18R of the legs 17 and 18. Pivot sockets 17S and 18S project inwardly from the upper rear corners of the legs 17 and 18. While all embodiments use the same horn and wheel, it should be understood that the terms “horn” and “wheel” when used in the claims, should not be construed as limited to a two legged horn or a wheel having core and tread of different materials or shapes, as the invention is quite applicable to other types of “wheel” construction and “horn” configuration.

[0034] Additional components shown in FIG. 1 and to be described in more detail later, include a wheel rivet 23 for mounting the wheel in the yoke between the horn legs 17 and 18 as the rivet is received through the holes 17H and 18H in the bottom rear portion of the legs 17 and 18. A lever operated locking spring 24 is secured by anchor screw 26 to the underside of the portion 19 of the horn bridging the space between the legs. Swivel locking pins 27 and 28 are receivable upward through a couple of apertures in the top of the horn.

[0035] An upwardly opening socket 31 in the top of the horn receives a bearing ball 32 and a downwardly projecting stem 33 molded into the top plate 34 which can be mounted to whatever object is to be supported by the caster assembly. One example of mounting can be done by screws (not shown) through the four corner holes 36 in the top plate. All of the components described to this point may be made of molded plastics, with a few possible exceptions such as mounting screws, axle 23, spring 24, screw 26, pins 27 and 28, and stem 33, some or all of which a manufacturer might prefer to make of metal.

[0036] The nature of the mounting of the brake operating lever 22 on the caster assembly can be readily understood with the help of reference to FIGS. 9 through 13. The lever 22 is generally rectangular when viewed from the top as in FIG. 13, and has a front edge 22F and a rear edge 22R. The rear portion of the lever is turned upwardly as shown in FIG. 9. The top surface has ribbing 22B on top adjacent the front edge 22F and ribbing 22C on the bottom of the upturned portion near the rear edge 22R. A cam body 22D projects downwardly from the bottom of the lever near the front end 22F. This cam has two pivot posts 22P projecting laterally from the cam body in opposite directions but on the same axis 22A.

[0037] The way that the brake operating lever is mounted in the horn can be appreciated upon reference to FIGS. 5, 6 and 7. In the above discussion, it was noted that there are pivot sockets 17S and 18S projecting inward from the legs 17 and 18, respectively, of the horn, and they are rearwardly spaced from the rear of the edge 21 of portion 19 of the horn. FIGS. 6 and 7 show that these sockets are downwardly opening shells. They are sized to receive in them, the pivot posts 22P (FIG. 10) projecting outward from the cam 22D on the bottom of the lever 22. Thus, referring to FIG. 5, the hole or yoke 41 behind edge 21 and in front of the sockets 17S and 18S, is able to receive the cam 22D when the lever is installed in the horn. Since the sockets are only half shells and open at the bottom, pivot posts 22B must be retained in the shells to function properly. Spring 24 shown in FIGS. 14 and 15, serves this function.

[0038] Referring now to the illustrations of the spring itself as shown in FIGS. 14 and 15, and as an example, spring 24 may be made of spring steel 0.035 inches thick and with a rear portion 24P extending from a rear edge 24R, upward and forward to locations 24D (FIG. 14) where it steps outward and is bent forward (FIG. 15). The wide portion of the spring extends forward from the bends 24D and edges 24N to edges 24E where it steps inward and the width is reduced to the same as at the rear end of the spring. The spring projects forward from the inward step and turns sharply upward at front end 24F. A portion of the spring at the front is cut away at 24C to provide two horizontally spaced tips 24T to engage the bottom, flanged ends of the swivel lock pins 27 and 28.

[0039] The spring has a U-shaped slot 24S, the rear edges of which begin adjacent the bends 24D but inboard from the lateral edges of the rear portion 24P of the spring. This slot provides a tab 24T which is a continuation of the upward and forwardly inclined rear portion 24P of the spring but a more gradual turn forward than at the bends 24D. This tab portion has an aperture 24A which receives the anchor screw 26 (FIGS. 1, 3 and 4) by which the spring is secured to the bottom of the portion 19 of the caster horn.

[0040] Prior to installation of the spring 24 in the horn, the two swivel locking pins 27 and 28, can be inserted from the bottom upward into guide holes 22H (FIG. 5) in the caster horn. As this is done with the horn upside down, the end flanges on the pins prevent them from falling entirely through the holes. Then the brake operating lever 22 can be placed with the cam 22D received in the yoke 41 at the rear of the horn and the pivot posts 22P received in the sockets 17S and 18S. Then the spring 26 can be installed, fastening it in place with the anchor screw 26. In this fastened condition, the spring is elastically deformed so the rear end portion of the spring resiliently engages the cam surface 22C of the brake operating lever 22, urging it toward the top of the caster horn and thereby urging the pivot pins 22P into the sockets 17S and 18S and securely retaining them in the sockets. The tips 24T of the front end of the spring engage the bottom end faces of the locking pins 27 and 28, retaining them in the holes 22H in the horn.

[0041] Referring back to FIGS. 1, 3, 6 and 8, the plate 34 has a built-in stem 33 molded into it, although it could be pressed into the plate after the molding of the plate itself. An end bearing ball 32 is received in the upwardly opening socket 31 of the horn. The stem has a peripheral external groove 33G in it, and the socket wall has an inwardly projecting circular rib at 31R. Therefore, when the stem is pushed into the hole 31, and after the lower end portion of the stem passes the rib 31, the inter-engagement of the rib 31R and the groove 31G prevent the stem and thereby the plate, from being pulled away from the caster horn. At the same time, however, the overall fit of the stem in the horn is not tight, so the horn can swivel readily relative to the plate 34.

[0042] As shown in the bottom view of the plate in FIG. 8, there is an array of twelve sockets 34S circularly spaced around the center 34C of the plate. Accordingly, they are circularly spaced about the axis of the stem 33 which is centered on the plate. The two pin receiver holes 22H are at the same radius from the axis of the stem as are the sockets 34S. Therefore, if the pins are pushed upward in the horn, their ends will enter two of the sockets at a time when the index position of the horn relative to the plate is such as to place any two holes in the plate in registry with the two holes of the horn in which the pins are located.

[0043] To apply the lock, the operator need only push the distal end portion 22R of the brake lever 22 downward in the direction of arrow 25 (FIG. 3), rocking the lever from its first and stable brake-released position, to its second position thereby engaging the rear end portion of the spring with the tread 13 of the wheel, as shown in FIG. 4. The location of engagement at 13E is forward of the pivot axis of the pivot posts 22P in the sockets 17S and 18S whereby the spring and the resilience of the tire tread urge the brake lever in the clockwise direction 25 about the pivot post axis to provide an “over center” action and retain the brake engaged in a second and stable wheel locking position. Thus the combination provides a bi-stable brake capability.

[0044] At the same time that the brake is engaged, the accommodation provided by the U-slot and spring tab 24T while the tab is fixed to the horn, resiliently permits the spring to rock at the rocker bend portion 24D. Therefore, the front end of the spring moves up and thereby the spring tips 24T, engaging the bottom ends of the lock pins 27 and 28, push the pins upward into whatever two sockets 34S in the plate happen to be in registry, or are placed in registry upon minor swiveling of the horn relative to the plate, and thereby lock the horn relative to the plate. So the one action of depressing the distal rear end of the brake operating lever 22 not only prevents the wheel from rolling, but also the horn from swiveling relative to the mounting plate 34. To release the swivel lock and wheel lock, it is only necessary to push down on the ribbed portion 22B at the top front of the lever 22, or pull up the ribbed portion immediately below the rear end 22R of the lever 22.

[0045] Referring now to FIGS. 16 through 19, and 23 and 24, all of these embodiments of the caster assembly, according to the present invention, have exactly the same horn and wheel construction. The only difference between the assembly of FIGS. 18 and 19, and that of FIGS. 2 and 3, is that the wheel lock and swivel lock components of the FIGS. 2 and 3 assembly are omitted in FIGS. 18 and 19, and the yoke opening 41 in the rear of the horn is covered by a snap cover 42. The only difference between the FIGS. 18 and 19 embodiment and that of FIGS. 23 and 24 is that the feature for mounting the caster assembly to the object to be supported by it such as a table or chest or cabinet or the like, is a top threaded stem instead of a top plate with stem. The stem portion received in the top of the horn is exactly the same in all of the illustrated embodiments. The only differences between the FIGS. 16 and 17 embodiment and the FIGS. 2 and 3 embodiment are that the attachment device instead of plate 34, the stem 53 has a smooth surfaced upwardly projecting stem portion 53U with a circular groove 53G receiving a split ring 54 for frictional engagement in a socket in the object to be supported by the caster assembly, and there is no swivel lock. The spring 24 can be the same even if swivel lock pins are absent. The lower portion 53L of the stem received in the horn is exactly the same as in the other embodiments, as the stem receiver in the horn is the same in all of the embodiments.

[0046] For the FIGS. 18 and 23 embodiments, the cover 42 is simply pushed into the opening 41. Since the cover is molded plastic, the cover legs 43 are elastically bent in slightly as the flanges 44 thereon are pushed past the sides of opening 41 and then they spring out and hook under edges 14B at each side of opening 41.

[0047] The molded plastic parts can be provided in colors and color combinations. While molded plastic has its advantages, metal or other materials might be used. Also, some possible additional embodiments could be contemplated. An example is a combination like in FIG. 23 but omitting the cover, and including the wheel lock or both the wheel lock and swivel lock. Another is a combination like FIG. 16 but with a cover instead of a wheel lock. Therefore, while the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. It should be understood that while the use of the word preferable, preferably or preferred in the description above indicates that the feature so described may be more desirable, it nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow.