Pole shaft coupling assembly and related method

A pole member for a stand, such as a medical stand, is defined by a first pole section and a second pole section. The first pole section includes a hollow end having a spline disposed therein for engaging a corresponding spline formed on a mating end of the second pole section. The splines are sized to interconnect wherein each spline includes tapering teeth and slots to create locking engagement therebetween and limit lateral play. A locking element engages the hollow end of the first pole section when inserted a predetermined distance therein.

FIELD OF THE INVENTION

The application relates generally to the field of assembled articles and more specifically to a coupling assembly for assembled articles, such as a supporting pole assembly for a medical mobile stand.

BACKGROUND OF THE INVENTION

Many articles are shipped to their end destinations in a fully assembled condition. Shipping containers for these articles therefore must be quite large; particularly for assemblies that are defined by relatively long or bulky portions. To ease shipability, some articles are transported in component or part form wherein final assembly is completed by an end user. Certain of these articles, such as stands and the like that include posts or poles among their component parts, are among such assemblies that could be shipped in a partially assembled state. In some versions, these poles are made to be telescopic to aid in assembly or in permitting adjustability using a smaller initial footprint. A competing issue exists, however, in that some assemblies may also have stability requirements. It is still a desire to be able to ship or initially store such articles in order to decrease the size of their respective shipping container, but yet permit dependable secure assembly of the discrete components, for example, in a permanent structure.

SUMMARY OF THE INVENTION

Therefore and according to one aspect, there is provided a support assembly comprising a pair of interlocking pole members; namely, a first pole member having a hollow end with a female spline disposed therein for mating engagement with a male spline formed at the end of a second pole member. The engaging teeth of the male and female splines combine to define an interface that directly and permanently engages the pole members and minimizes lateral play. In one version, the teeth are angled to create an interference fit.

In one version, the hollow end of the first pole member includes a contoured mating hole sized to receive an extending portion of the second pole member.

In another version, a concave washer with a serrated edge or other locking element engages the hollow end of said first pole member when the second pole member is inserted a predetermined distance into the hollow end of the first pole member.

According to one version, the teeth and the slots of the respective splines are tapered but in which the teeth of the male spline are larger than the corresponding tapered slots of the female spline, thereby producing line contact and a stable and secure interconnection.

According to another aspect, there is provided a mobile stand, said mobile stand comprising a wheeled base and a vertically extending pole member in which each of the pole member and wheeled base are interconnected, the pole member having a first spline and the wheeled base having an extending mating section that includes a second spline. The first and second splines interface to form a permanent connection. The vertically extending pole member can be made from two or more separate and interlocking sections, each of the interlocking sections being defined by respective mating ends.

The interlocking sections are defined by a first pole section having a hollow end with a female spline disposed therein for mating engagement with a male spline formed at the end of a second pole section. The engaging teeth of the male and female splines combine to define an interface that directly and permanently engages the pole sections and minimizes lateral play. In one version, the teeth are angled to create an interference fit.

According to yet another aspect, there is described a method for manufacturing a pole assembly, said method including the steps of providing a first pole section with a hollow first end having a first spline, providing a second pole section having a first end and providing a second spline complementary to said first spline at said end. One of said splines of the first and second poles includes a plurality of axial teeth and the other of said splines includes a plurality of slots, each of said slots being sized to receive said teeth in an interference fit.

An advantage is that sturdy, stable and reliable assembly is made possible using the herein described stand, while still permitting portions thereof to be shipped as component parts.

Another advantage is that the assembly process is relatively easy, while still being permanent and secure.

These and other features and advantages will be readily apparent from the following Detailed Description, which should be read in conjunction with the accompanying drawings.

DETAILED DESCRIPTION

The following description relates to an exemplary mobile stand depicting salient features of the present invention. More specifically, the mobile stand includes a pole assembly made in accordance with the inventive concepts defined herein. It will be readily apparent, however, that various modifications and/or changes could be made within the intended scope of the concepts that are described herein. In addition, certain terms such as “upper”, “lower”, “distal”, “proximal”, “above”, “below” and the like are used throughout the course of this description in order to provide a convenient frame of reference with regard to the accompanying drawings. These terms, however, are merely intended to provide clarity and not to narrow the scope of the claimed invention, except where so specifically indicated.

Referring toFIG. 1, there is shown a mobile stand20defined in accordance with an exemplary embodiment. The mobile stand20is defined by a wheeled base24, which includes a plurality of wheels27extending from the bottom of a set of base legs26, the wheels being rotatably secured thereto by casters28or other suitable means. In this version, five (5) base legs and wheels are shown, although this parameter can be easily and suitably varied. The base24further includes a center stanchion or post29having a hollow end100that is sized to receive one end of a support pole member30. As described herein, the support pole member30is made of a pair of interlocking pole sections; namely a lower pole section34and an upper pole section38that are assembled together into a unitary member, as a subassembly.

A medical instrument, such as a vital signs monitoring device44, (such as a SPOT ULTRA monitoring device sold by Welch Allyn, Inc. of Skaneateles Falls, N.Y.), is attached by known means to the upper end of the upper pole section38in addition to other hardware, including a support basket48. The herein shown vital signs monitoring device44is configured to measure various physiological parameters of a patient (not shown) including, but not limited to body temperature, blood pressure, respiration, pulse rate and blood oxygen saturation (pulse oximetry). Other instruments/devices can be used depending on the application, wherein the instrument shown is herein intended to be merely exemplary. The support basket48is secured to the upper pole section38by means of a bracket52, which is attached to the exterior of the upper pole section by a set of fasteners56or other convenient means. Alternatively, the support basket48could be made integral with the upper pole member38. The support basket48according to this embodiment is used to conveniently store accessories (not shown) for the attached monitoring device44, such as thermometry probe covers, inflatable blood pressure cuffs and the like. Other suitable storage or securing means such as hooks can also be provided, depending on, for example, the instrument and application of the mobile stand20.

The mating interface of the two interlocking pole sections34,38of the pole member30according to this exemplary embodiment is now described in greater detail with reference toFIGS. 2 and 3.

According to this embodiment, the upper end of the lower pole section34is hollow and includes a contoured female mating hole or opening60, which further includes an insert section64, the diameter of the mating hole being narrowed at a lower end68of the insert section. A female spline72is formed within an axial portion of the insert section64proximate the opening60. The female spline72is defined by a series of axially extending slots74disposed about the inner circumference of the insert section64proximate the hollow upper end of the lower pole section34. Each of the slots74taper inwardly from a larger width dimension adjacent the opening60to a narrower width dimension at a bottom end. Each slot74is bounded by a sidewall projecting radially from the spline72, the slots being separated from one another by annular sections77.

Still referring toFIGS. 2 and 3, the lower end of the upper pole section38includes mating features that are complimentary to those provided in the lower pole section34. To that end and according to this exemplary embodiment, a male spline80is provided at the lower end along an axial portion of the pole section38. The male spline80is defined by a plurality of axially extending teeth84formed about the entire outer circumference of the upper pole section38. The teeth84extend axially; that is, in a direction that is parallel with the primary axis of the upper pole section38wherein each tooth preferably includes a pair of sidewalls that taper outwardly from a distal end87to a proximal end86of each tooth. The outward taper of the teeth84of the male spline80is slightly larger than the taper defined by the slots74of the female spline72. The teeth84are equally spaced about the circumference of the axial portion of the upper pole section38, each of the teeth being separated by annular sections85.

Coextensive with the lower end of the upper pole section38is an extending cylindrical section88that is distally arranged relative to the male spline80. The extending cylindrical section88extends over an axial section of the pole section38and has a diameter that is narrower than the outer diameter of either spline72,80. The cylindrical section88includes a distal section having a center opening (not shown), aligned along the primary axis of the pole section38. This center opening according to this embodiment is threaded and configured to receive a fastener96. The fastener96is used to secure a locking washer92to the distal end section of the upper pole section38. The locking washer92is defined by a concave shape, including a plurality of serrated portions98that are circumferentially disposed.

When the lower and upper pole sections34,38are assembled together as shown inFIG. 3, the extending cylindrical portion88of the upper pole section38is sized to fit within the opening60of the insert section64and be advanced axially into the lower portion68thereof. As the upper pole section38is advanced axially, the teeth84of the male spline80engage the tapered slots74of the female spline72without interference between the annular sections77,85. The male and female splines72,80defined herein together define a mating interface such that when the teeth84of the male spline80engage the slots74of the female spline72, the outward taper of the male teeth84being slightly larger than that of the slots74of the female spline72creates line-contact made between each mating tooth. As engagement increases axially, coupler material is slightly displaced to create surface to surface contact, which increases overall interface effectiveness.

The foregoing interface between the engaging splines72,80of the engaged pole sections limits lateral play as well as radial motion between the mating upper and lower pole sections34,38. In addition, a diametrical interface is provided between the extending cylindrical portion88and the mating hole68distal to the splines72,80that further limits lateral play between the two pole sections34,38.

In addition, the locking washer92further acts to engage the upper and lower pole sections34,38together in a locking relationship. As noted, the locking washer92is affixed to the distal neck or end of the upper pole section38by means of a fastener96, such as a screw, bolt or other threaded fastener. The orientation of the locking washer92is such that the insertion of the upper pole section38into the mating hole60of the lower pole section34is unidirectional. The diameter of the locking washer92is greater than the narrowed diameter of mating hole68and therefore the sharp edges of the serrated sections98penetrate the inner diametrical wall of the insert portion64as the upper pole section38is axially inserted into the lower pole section34. The natural concave shape of the locking washer92prevents removal from the lower pole section34, thereby preventing the mating pole sections34,38from being separated and permanently locking them in direct engagement.

Referring toFIG. 4, the lower end of the lower pole section34and the wheeled base24of the herein described mobile stand20also can be assembled using a secured locking assembled arrangement akin to that depicted inFIGS. 2 and 3. Similar parts are herein labeled with the same reference numerals for the sake of clarity. In this instance, the lower end of the lower pole section34includes an arrangement similar to that of the lower end of the upper pole section38,FIG. 2. That is, the lower pole section34includes a male spline80having a series of axially disposed and tapered teeth, an adjacent distal extending cylindrical section88and a locking washer92attached to a distal neck or end of the pole section, respectively.

According to this exemplary embodiment, the wheeled base24includes a hollowed vertically extending shaft102that is provided within the center stanchion29of the base. This shaft is defined by a mating hole or opening106that is sized to receive the lower end of the lower pole section34, the shaft further including a complementary female spline110. The opening106of the extending shaft102is contoured and is defined by a diameter that decreases or narrows in relation to the open end thereof. Preferably, the male spline80includes a set of axially extending teeth84that are tapered along their length, like those previously discussed and shown inFIGS. 2,3for engagement within complementary tapered slots formed within the female spline110. As in the preceding, axial engagement of the lower end of the pole section34into the mating hole106of the base shaft102causes the extending section88of the pole section end to engage therewith, including the locking washer92, the latter being permanently secured to the extending section88by a threaded fastener96that is attached to the distal neck, the locking washer including a plurality of serrated portions that each engage the interior diametrical wall of the shaft106when the pole section34is axially engaged with the base24. The engagement between the splines72,80, reduces lateral play wherein the pole section34becomes permanently and stably secured to the base24.

PARTS LIST FOR FIGS.1-4

It will be readily apparent that other modifications and variations are possible that include the inventive concepts according to this application. For example, it should be noted that the splines could be reversibly located; that is, the male spline could be situated on the lower pole section and the female spline situated along the upper pole section of the pole member.