JP2019508122A - Rotating article mounting device - Google Patents

Abstract

The present disclosure provides an adjustable mounting device that allows a user to fine-tune the placement of items that can be mounted without concern for the exact placement of the mounting device. Certain attachment devices can be used to hang a picture and can be rotated after attachment to a vertical surface.

Description

  The present disclosure relates generally to articles useful for mounting articles, and more particularly to a rotatable device for mounting a picture, frame, artwork, etc. to a wall.

  Hanging a painting or other item on a wall often requires accurate measurements to ensure that the painting is horizontal or that the two paintings are aligned. In order to hang a painting, it usually requires fastening means (eg, nails, screw hangers, or hooks) to secure the painting to the wall. There are a number of fastening mechanisms. Conventional painting hangers often include a hook secured to the wall. Such hooks are typically curved upward and are configured to receive a picture frame or a work support bracket.

  However, there are problems with traditional methods of painting. Many fastening mechanisms require expensive or cumbersome tools for installation. Other fastening mechanisms can only hold a defined weight, and if you try to replace a heavier item after hanging it initially, you must remove the existing painting hanger and replace it with a different hanger that can handle the larger weight. I must. Some fastening mechanisms can easily slip out of the wall or fall off when not used properly or when used to hang heavy items. And depending on the type of backing hardware on the back of the picture or item being hung, the user may need to select a different wall hanger that corresponds to the metal fitting of the item to be hung.

  Another problem can be difficult if the user attempts to place the painting at the correct location on the wall, with the hook (s) of the painting frame not aligning with the position of the nail or screw. A problem also arises when trying to align two different pictures, the hooks of the different picture frames are not in the same position from the top of the picture frame. This raises the problem that simply aligning nails on the wall does not guarantee mutual alignment of the paintings themselves. For this reason, it takes time and effort to know where to attach the nail or screw on the wall.

  A further problem with hanging paintings in a standard way relates to how large paintings are hung on the wall. Large paintings often have multiple hooks on the frame to distribute the weight of the painting. For this reason, the user has to use a plurality of nails or hooks, and creates many damage points on the wall. In addition, the user needs to level the nails or hooks precisely in order to hang the item to be hung horizontally, which can be a difficult and frustrating task.

  Currently, the standard way to reposition a painting that is not horizontal or at an appropriate height is to remove the painting from the wall, remove its nail or screw from the wall, and then place the nail in a different position, Repaint the painting and check if the painting is at the desired height. If the painting is not at the desired height, the entire process will be repeated again. This process of aligning and leveling the painting by trial and error can be time consuming, create unwanted holes, reduce the strength of the walls, and ultimately create a need for repair.

  Some hangers are designed to attempt to eliminate at least some of the problems described above. U.S. Pat. No. 5,695,147 to Zimmerman uses a rotatable body that can lengthen or shorten a hanging wire, and uses a flexible wire fixed at both ends to a suspended object. Describes an adjustable hanging device that controls the length and shifts the painting on the wall up and down. U.S. Pat. No. 6,666,425 to Ferguson has a body with a plurality of teeth arranged vertically and an adjustable bracket and is painted on any one of the teeth arranged vertically. Describes a vertically adjustable painting hanger that can be positioned. U.S. Pat. No. 8,061,054 to Rabin is adjustable, having an elongated strap and a pair of spaced sliders, which can be marked on the wall to facilitate leveling of the attached picture Describes a painting device. U.S. Pat. No. 6,572,067 to Kamenstain describes an adjustable picture hook with a gear coupled to the hook that can adjust the picture horizontally or vertically. U.S. Pat. No. 4,892,284 to Kelrick describes an adjustable hanger having a rack and pinion for continuously moving an object in the horizontal direction and a screw for continuously moving the object in the vertical direction.

  The inventors of this application are easy to use, do not necessarily require the use of tools, are relatively inexpensive, allow for hanging articles with various backing metal configurations, and facilitate the placement of paintings Recognize the need for a system that allows the user to quickly and accurately adjust.

  Various embodiments of the present disclosure advantageously address some or all of the above constraints on existing wall hanging devices. For example, various embodiments of the present disclosure provide the following advantages: (1) easy to hang, (2) does not damage the wall, (3) adjustments in use without removal from the wall (4) No need to use a hanger on the back of the frame / artwork to be hung, allowing the user more ease and freedom of installation of the item, (5) The item to be hung An attachment device having at least one of (6) improving the load carrying capacity of a single device is provided.

  Some embodiments of the present disclosure relate to an attachment device for hanging an object such as a painting or mirror that allows the painting (or the item to be hung) to be adjusted after the painting device is secured to a wall. This allows easier leveling of the item to be hung and potential adjustment of the orientation of the item after installation of the mounting device.

  Some embodiments of the present disclosure are attachment devices that include a first portion that includes a protrusion and a second portion that includes a receiving portion into which the protrusion of the first portion can fit. At least one of the first part and the second part has a load supporting form, and the first part and the second part can be fitted together, and when fitted, the first part and the second part are rotated about the common axis. The present invention relates to an attachment device.

  Some embodiments of the present disclosure are methods for preparing an attachment device that can hold an article to a wall, wherein (1) a first portion that includes a protrusion, and (2) a protrusion in the first portion. Providing a second part including a receiving part capable of being fitted, wherein at least one of the first part and the second part has a load supporting form having an angle; Joining the first part and the second part such that the protrusion fits within the receptacle so that the first part and the second part can rotate about a common axis.

  Some embodiments of the present disclosure are kits, comprising a first part that includes a protrusion and a second part that includes a receiving portion into which the protrusion of the first part can fit. A mechanical fastener or adhesive fastener capable of attaching, hanging, adhering and / or attaching one of the first part and the second part to a wall, and a frame of one of the first part and the second part, a photograph A mechanical fastener or adhesive fastener that can be attached to, hung, glued, and / or attached to a work of art, etc., and at least one of the first part and the second part has a load supporting form having an angle. The first part and the second part relate to a kit that can be fitted and can be rotated about a common axis when fitted.

  In some embodiments, the protrusion and the receiver are each substantially circular or substantially cylindrical. In some embodiments, the first portion includes one or more teeth of the protrusion. In some embodiments, the second portion includes a detent around the outer surface of the protrusion. In some embodiments, the second portion includes a detent around the inner surface of the receptacle. In some embodiments, the detents around the inner surface of the receptacle and the teeth around the outer surface of the protrusion are secured to each other so as to hold both the first and second parts in a stationary position. Engage with. In some embodiments, the protrusion and the receiver provide audible sound and / or physical feedback to the user when properly fitted. In some embodiments, the attachment device can be attached, hung, glued and / or affixed perpendicular to the plane. In some embodiments, the attachment device includes an adhesive strip on one of the first portion and the second portion to allow the attachment device to be adhered to the wall. In some embodiments, the attachment device includes a mechanical fastener on one of the first portion and the second portion to allow the attachment device to be attached, hung, glued and / or affixed to the wall. including. In some embodiments, the attachment device includes an adhesive strip on one of the first portion and the second portion to allow the attachment device to be adhered to a frame, a photograph, a work of art, or the like. In some embodiments, the first portion includes one or more undulations around the protrusion. In some embodiments, the second portion includes a detent around the outer surface of the protrusion. In some embodiments, the detents around the inner surface of the receptacle and the teeth on the outer surface around the protrusions are secured to each other so as to hold both the first and second parts in a stationary position. Engage with. In some embodiments, the protrusion and the receiver provide audible sound and / or physical feedback to the user when properly fitted.

1 is a schematic view of an exemplary embodiment of a mounting device generally described in this disclosure.

It is a schematic sectional drawing of embodiment shown in FIG.

FIG. 3 is a schematic view of the exemplary embodiment of FIGS. 1 and 2 showing how the first and second portions are mated.

1 is a schematic view of an exemplary embodiment of a mounting device generally described in this disclosure.

It is a schematic sectional drawing of embodiment shown in FIG.

1 is a schematic view of an exemplary embodiment of a mounting device generally described in this disclosure.

2 is a photograph of a front side of an exemplary embodiment of a mounting device generally described in the present disclosure.

8 is a photograph of the back side of the exemplary embodiment shown in FIG.

9 is a photograph of the front side of the portion of the exemplary embodiment shown in FIGS. 7 and 8 applied to a wall.

10 is a photograph of a rear side of a portion applied to an attached item in the exemplary embodiment shown in FIGS.

FIG. 11 is a photograph of the front side of the attached item shown in FIG. 10. As shown in FIGS. 11 and 12, the item can be rotated. FIG. 11 is a photograph of the front side of the attached item shown in FIG. 10. As shown in FIGS. 11 and 12, the item can be rotated.

  The figures are not necessarily to scale. Some features may be exaggerated or minimized to show details of particular components. Accordingly, the specific structural and functional details disclosed herein should not be construed as limiting, but as a representative basis for teaching those skilled in the art the various uses of the present invention. Should only be interpreted.

  The present disclosure is described in more detail below with reference to the accompanying drawings. In the accompanying drawings, exemplary embodiments are shown. However, the scope of the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth or shown herein.

  The adjustable painting device of the present disclosure allows the user to fine-tune the placement of the painting without worrying about the exact placement of the painting device. In some embodiments, the device also prevents unnecessarily drilling holes in the wall.

  1 to 3

  1-3 illustrate an exemplary embodiment in which the attachment device 100 includes a first portion 110 (also referred to as “A”) and a second portion 120 (also referred to as “B”). Yes. In the particular embodiment shown in FIG. 1, the first and second portions are generally square (the person skilled in the art will understand that many alternative shapes can be used, such as a rectangle, a pentagon, a diamond, etc. Dewa) The first portion 110 and the second portion 120 can have the same or different shapes. Each of the first portion 110 and the second portion 120 has a thickness. Any desired thickness can be used. An exemplary desired thickness is from about 0.65 inches to about 0.125 inches. The first and second portions can be made from any desired material, such as plastic.

  In some embodiments, at least one of the first portion 110 and the second portion 120 has a load bearing configuration. As used herein, the term “load bearing configuration” means that the structure or shape provides load bearing capacity. In the embodiment shown in FIG. 1, the upper secondary surface 122 (or the first lateral secondary surface 124 and the second lateral secondary surface 126, or the lower secondary surface 128) of the first portion 110 or the second portion 120 is It has a shape or structure that can hold the weight of the item to be hung. In this particular embodiment, the item to be hung is supported on the upper secondary surface 122. In at least some embodiments, the attachment device greatly increases the effective attachment area or object compared to traditional nails or hooks. Because nails and hooks are relatively small compared to the item being hung, it is difficult to perfectly align the nail / hook with the item being hung. By increasing the size of the portion of the mounting device on which the item is hung (eg, the size of the upper secondary surface compared to a nail or hook), the user places the item on the mounting device and when the user places the mounting device The degree of freedom when placing is significantly increased. Also, in order to assist in the installation of larger or heavier items such as woodcuts and canvases, adhesive strips (illustrated below) on either or both subsurfaces of the first portion 110 and the second portion 120 Or other fixing surfaces can be provided.

  The first portion 110 includes a protrusion 130 that extends outwardly from at least one major surface of the first portion 110. In the particular embodiment shown in FIG. 1, the protrusion 130 extends outward from the front major surface 140 (on the opposite side of the rear major surface 145) of the first portion 110. The protrusion 130 can have any desired thickness and diameter. In some embodiments, the thickness is from about 0.100 inch to about 0.380 inch. In some embodiments, the diameter is from about 1 inch to about 4 inches. In some embodiments, the protrusion 130 is at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 75%, at least 80%, at least 80% of the total area of the first portion 110. It accounts for 85%, at least 90%, or at least 95%. In some embodiments, the thickness of the protrusion 130 is less than, equal to, or greater than the thickness of the first portion 110. The protrusion 130 is shown as a circle in the particular embodiment of FIG. However, the protrusions can have any desired shape, such as, for example, a circular or cylindrical shape. As shown in the figure, the protrusion 130 is made thinner as the front main surface 140 is approached.

  The second portion 120 includes a first main surface 154 opposite to the second main surface 156 and a receiving portion 150 into which the protruding portion 130 can be fitted. In the particular embodiment shown in FIG. 1, the receiver 150 is a similar but slightly larger indentation of shape and size to allow the protrusion 130 to fit snugly within the receiver 150. In some embodiments, the protrusion 130 can be rotated within the receptacle 150, and the receptacle must be sized and shaped accordingly.

  As shown in FIG. 3, in order to fasten the first portion 110 to the second portion 120, the receiving portion 150 can be rotatably fitted with the protruding portion 130. The obtained attachment device 100 can be rotated about the rotation axis 180.

  In some embodiments, the attachment device provides feedback to the user when the device is properly or effectively mated. Any desired feedback mechanism can be used. Some exemplary feedback mechanisms include, for example, auditory or physical mechanisms.

  In some exemplary embodiments, the protrusion 130 of the first portion 110 includes a plurality of relief structures that extend outwardly from the outer peripheral surface of the protrusion 130. 1-3 show the teeth 160, the relief structure can be any structure having a texture or protrusion (eg, sandpaper) protruding from the outer peripheral surface. In some embodiments, the receiving portion 150 of the second portion 120 includes a plurality of detents 165 into which the teeth 160 fit. In some embodiments, the detent 165 around the inner surface of the receiver 150 and the teeth 160 around the outer surface of the protrusion 130 place the first portion 110 and the second portion 120 in a stationary position. Engage with each other to hold together. In some embodiments, when the tooth 160 fits in the detent 165, an audible noise (e.g., a click) and / or a physical "notice" that the two structures are properly or effectively fitted. Click ". In some embodiments, the first portion and the second portion are calibrated to each other. In some embodiments, the teeth 160 are substantially evenly spaced. In some embodiments, the teeth are 0.5 to 3.0 mm apart from each other.

  In some embodiments including teeth 160 and detents 165, the first portion 110 and the second portion 120 are rotated like a ratchet to facilitate leveling of the attachment device 100 (and the item to be hung). Can be made. This can be done easily even after attaching the attachment device 100 to the wall, after fastening, or after attaching.

  In the embodiment shown in FIGS. 1-3, the teeth 160 are shown in the first portion 11 and the detent 165 is shown in the second portion 120. However, those skilled in the art will recognize that the tooth 160 may be in either the first or second part (or in another part of the attachment device) and that the tooth / undulation structure and detents will be provided once the attachment device is assembled. It will be appreciated that can be in either the first or second part (or in another part of the attachment device) as long as they are aligned.

  4 and 5

  4 and 5 illustrate an alternative embodiment of the attachment device 200 as generally described herein. The attachment device 200 includes a first portion 210 and a second portion 220. The first portion 210 and the second portion 220 have different shapes from each other in the particular embodiment of FIGS. 4 and 5 (the second portion has a generally square shape). As described above and generally herein, the first portion 210 includes a receiving portion 250 and the second portion 220 includes a protrusion 230 that can be fitted. FIG. 5 is a sectional view.

  All of the features of the attachment device 200, the first portion 210, and the second portion 220 can be included in an embodiment similar to the particular embodiment shown in FIGS.

  As shown in FIG. 4, in order to allow one or both of the first and second portions of any of the embodiments described herein to adhere the attachment device to the wall, One of the second portions can include an adhesive strip. Exemplary adhesive strips include, for example, any of the COMMAND ™ brand products sold by 3M Company, for example, the COMMAND ™ painting piece from 3M Company. In one embodiment, the adhesive strip is adhered to a section of the first (or second) portion adjacent to the item to be hung and a second (or first) portion of the section adjacent to the wall. Methods of application, use, and formation of adhesive strips, and the composition of those general types of adhesive strips are described, for example, in US Pat. Nos. 5,672,402, 6,403,206, 7,781,056, 6,001,471, 6,569,521, and 7,078,093, all of which are incorporated herein.

  Alternatively, the attachment device includes a mechanical fastener on one of the first and second portions to allow the attachment device to be attached, hung, glued and / or affixed to the wall.

  FIG.

  FIG. 6 illustrates an alternative embodiment of a mounting device 300, generally described herein. The attachment device 300 includes a first portion 310 and a second portion 320. The first portion 310 corresponds to the easel backing 380 of the painting frame 370. The protrusion 330 of the easel backing 380 (ie, the first portion 310) may be made integral with the backing 380 (ie, the backing material and the protrusion are monolithic), or For example, you may affix with the adhesive piece mentioned above. The second portion 320 includes a receiver 350 that can mate with the protrusion 330, as generally described above and herein. Although only a single protrusion 330 and corresponding receptacle 350 are shown, the first portion 310 comprises two or more protrusions (with corresponding receptacles) in other embodiments of the present disclosure. You can also.

  All of the features of the attachment device 300, the first portion 310, and the second portion 320 can be included in an embodiment similar to the particular embodiment shown in FIG. Such an embodiment need not be limited to the attachment of a picture frame, but can be provided with integral or coupled protrusions on the wall facing surface of any attached item. Such features can reduce the distance between the wall and the item relative to other embodiments described herein.

  7 to 12

  7-12 are photographs showing the structure of an exemplary attachment device in accordance with the general teachings herein. FIG. 7 illustrates an exemplary first portion 410 and second portion 420 (front view). FIG. 8 shows a rear view of the first portion 410 and the second portion 420 of FIG. FIG. 9 shows the first portion 410 bonded to the wall. FIG. 10 shows the second part 420 bonded to the item to be attached / hanged (frame). The second part of FIG. 10 is mated with the first part of FIG. The item to be hung is adjusted by rotating the first and second parts relative to each other to achieve the desired leveling of the hung item. FIG. 11 shows the resulting hanging / attaching photo frame. FIG. 12 shows that the photo frame can be rotated along the axis of the attachment device even after the photo frame (or any attached item) is attached. This can provide the user with practical (leveling) and aesthetic possibilities.

  Method

  Some embodiments of the present disclosure are methods for preparing an attachment device that can hold an article to a wall, wherein (1) a first portion that includes a protrusion, and (2) a protrusion in the first portion. A step of providing a second part including a receiving part capable of being fitted, wherein at least one of the first and second parts is provided with a load supporting form having an angle; and when fitted, the first part And joining the first part and the second part such that the protrusion fits within the receiving part so that the second part can rotate about the common axis. In some embodiments, the method further includes rotating the portions relative to each other to properly fit the first portion and the second portion. In some embodiments, the method further provides an audible sound and / or feedback to the user to confirm that the first and second portions are properly mated. Until the parts are rotated relative to each other. In some embodiments, the method further includes applying an adhesive strip to the back major surface of one of the first portion and the second portion, attaching the first portion or the second portion to the wall, and hanging. Adhering and / or sticking, and applying an adhesive piece to the other front main surface of the first part and the second part, the first part or the second part being a frame, a photograph, a work of art Attaching, hanging, adhering and / or sticking to the like.

  In addition to all the various advantages described herein, the attachment device described herein makes it easier to hang large items and allows the items to be adjusted to be horizontal. In some embodiments, they allow the user to change the orientation of the item to be hung or attached after installation of the attachment device. In some embodiments, the attachment device does not damage (to the wall and the item being hung). The mounting device described herein is perfect for users who want freedom. The attachment device described herein provides easy adjustment by both users after both the attachment device and the article to be attached are attached to the wall. In some embodiments, the attachments described herein can be attached perpendicularly to any plane, hung, glued and / or affixed.

  The recitation of all numerical ranges by endpoints shall include all numbers contained within that range (i.e., a range of 1 to 10 includes, for example, 1, 1.5, 3.33 and 10).

  The terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers, and / or sections. It will be understood that regions, layers, and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section and are not necessarily used to describe the order or timeline. Is not. The terms so used are interchangeable under appropriate circumstances, and the embodiments of the invention described herein are operable in an order other than those described or illustrated herein. It should be understood.

  The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the terms “comprises” and / or “comprising”, or “includes”, and / or “including” refer to the feature mentioned, Specify the existence of a region, integer, step, action, element, and / or component, and the presence of one or more other features, regions, integers, steps, actions, elements, components, and / or groups thereof It will be further understood that no addition is excluded.

  In addition, in order to explain the relationship between one element illustrated in the figure and another element, in this specification, “lower side” or “lower”, and “upper side” or “upper”, and “front” or Relative terms such as “after” may be used. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation shown in the figures.

  All references to other materials herein are meant to incorporate the entire reference.

Those skilled in the art will appreciate that many changes can be made to the details of the above-described embodiments and examples without departing from the underlying principles. In addition, various modifications and variations to the present disclosure will be apparent to those skilled in the art without departing from the spirit and scope of the present disclosure. Accordingly, the scope of the present disclosure should be defined only by the following claims.

Claims (20)

An attachment device,
A first portion including a protrusion;
A second part including a receiving part into which the protruding part of the first part can be fitted;
At least one of the first part and the second part has a load support configuration;
The first device and the second device can be fitted to each other, and when fitted, can be rotated around a common axis.   The attachment device according to claim 1, wherein each of the protruding portion and the receiving portion has a substantially circular shape or a substantially cylindrical shape.   The attachment device according to claim 1 or 2, wherein the first portion includes one or more teeth around the protrusion.   The attachment device according to any one of claims 1 to 3, wherein the second portion includes a detent around the outer surface of the protrusion.   The mounting device according to any one of claims 1 to 4, wherein the second portion includes a detent around the inner surface of the receiving portion.   The detents around the inner surface of the receptacle and the teeth around the outer surface of the protrusions hold the first part and the second part together in a stationary position, 6. A mounting device according to claim 4 or 5, wherein the mounting devices are securely engaged with each other.   The attachment device according to any one of claims 1 to 6, wherein the protrusion and the receiving portion provide an audible sound and / or physical feedback to the user when properly fitted.   The attachment device according to any one of claims 1 to 7, wherein the attachment device can be attached, hung, glued and / or attached perpendicular to a plane.   9. The attachment device according to claim 1, wherein the attachment device includes an adhesive piece on one of the first part and the second part so as to allow the attachment device to be adhered to a wall. The mounting device described in 1.   The attachment device includes a mechanical fastener in one of the first portion and the second portion to allow the attachment device to be attached, hung, glued and / or affixed to a wall. The attachment apparatus as described in any one of Claims 1-9.   The attachment device includes an adhesive piece on one of the first part and the second part so as to allow the attachment device to be attached to a frame, a photograph, a work of art or the like. The mounting device according to any one of 10.   The attachment device according to any one of claims 1 to 11, wherein the first portion includes one or more undulations around the protrusion.   The attachment device according to any one of claims 1 to 12, wherein the second portion includes a detent around the outer surface of the protrusion.   The detents around the inner surface of the receptacle and the teeth around the outer surface of the protrusions hold the first part and the second part together in a stationary position, 14. The attachment device of claim 13, wherein the attachment devices are securely engaged with each other.   15. The attachment device according to any one of claims 1 to 14, wherein the protrusion and the receiver provide an audible sound and / or physical feedback to the user when properly fitted. A method of preparing an attachment device capable of holding an article on a wall,
(1) a step including a first portion including a protruding portion, and (2) a second portion including a receiving portion into which the protruding portion of the first portion can be fitted, the first portion and Providing at least one of the second portions has a load support configuration having an angle;
The first portion and the second portion so that the protrusion fits within the receiving portion so that the first portion and the second portion can rotate about a common axis when fitted. Joining the step.   The method of claim 16, further comprising rotating the portions relative to each other to properly fit the first portion and the second portion.   By rotating the parts relative to each other until they make an audible sound and / or provide feedback to the user that the first part and the second part are properly fitted. The method according to claim 16 or 17, further comprising a step of confirming. Applying an adhesive piece to a rear main surface of one of the first part and the second part, and attaching, hanging, adhering and / or attaching the first part or the second part to a wall; When,
Applying an adhesive piece to the other front main surface of the first part and the second part, attaching the first part or the second part to a frame, a photograph, a work of art, etc. The method as described in any one of Claims 16-18 which further includes the process of attaching. A kit,
A first portion including a protrusion;
A second part including a receiving part into which the protruding part of the first part can be fitted;
A mechanical fastener or an adhesive fastener capable of attaching, hanging, adhering and / or attaching one of the first part and the second part to a wall;
A mechanical fastener or an adhesive fastener capable of attaching, hanging, adhering and / or attaching one of the first part and the second part to a frame, a photograph, a work of art or the like. And at least one of the second portion and the second portion has a load support configuration having an angle,
The kit, wherein the first part and the second part can be fitted together and can be rotated about a common axis when fitted.