TITLE OF INVENTION

BUILDING BLOCKS FOR TOY CONSTRUCTION FASTENING ASSEMBLY

PRIORITY CLAIM AND CROSS REFERENCE

This application claims the benefit of priority from non-provisional application U.S. S.N. 13/152,773 filed June 3, 2011. Said application is incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention is directed generally to a fastening assembly and more particularly to a releasably engaged fastening assembly using snap-on components. BACKGROUND ART

Fabricated blocks or parts have been in existence for many years, and their

manufacturing techniques have remained fairly consistent over the past 80 years.

Among the most prominent and widely used fabricated blocks include construction sets marketed under the tradename LEGO®, The Lego Group (Billund, Denmark), including its various brands and tradenames such as DUPLO, BIONICLE, MINDSTORMS, the BELVILLE, KNIGHTS' KINGDOM and EXO-FORCE, the Brick and Knob configurations and the Minifigure. In the LEGO proprietary toys units, wheels, gears, blocks, axle pins, stop bushings are designed to be compression fitted. Lego's axle pins are provided with rigid splines disposed on their curved surfaces and configured to be received by one or more sockets on one or more blocks, wheels and/or gears. The sockets typically include various rigid matching splines that do not experience substantial change in size or shape when axle pins are mounted. However, the current designs have limitations, such as, for example, that the axle pins are fabricated in various fixed lengths. Further, there is a limited number of axle pin lengths which may be feasibly produced. Therefore, there arises a need for user-configurable assemblies which provide added flexibility in the design or construction of an assembly, in particular, varying sizes of axle pin lengths.

Further, the seemingly ubiquitous toy construction sets TINKERTOY ® marketed by Hasbro, Inc include connecting blocks and rods that are compression fitted. As will be demonstrated elsewhere in this document, each interface between a connecting block and a rod lacks positive securement, thereby allowing the interface to be easily overcome by mere over torquing or pulling of the rod against a socket of the connecting block.

U.S. Pat. No. 5803782 discloses a plurality of connector blocks and connecting members. Each connector block is formed to have a body portion defining a plurality of sides that extend outwardly from a central region. Each side is substantially cross- shaped and has a substantially cross-shaped receiving slot. A plurality of elongated connecting members are also provided for releasable engagement within the receiving slots of the connector units. This patent discloses connecting members that are specially engineered to result in a substantially cross-shaped or planar profile. Further, the connecting members may only be mated to the connector units having cross- shaped receiving slots. As such, the prior art only works with purpose built connecting members.

Thus, there arises a need for a fastening assembly that is versatile, simple to manufacture, low cost to produce and comprises a component that can be engaged with a non-proprietary or purpose-built component part, a more commonly available material to create a releasably engaged assembly and allow a user to vary the dimensions of the component parts of an assembly.

DISCLOSURE OF THE INVENTION

The present invention is directed toward a fastening assembly for constructing a releasably engaged structure. The assembly includes a plurality of connecting blocks. Each connecting block includes at least one circular socket having an internal wall, a central axis and at least one spline. Each spline includes a longitudinal axis and a transverse cross-sectional area. In one embodiment, the circular socket is disposed with its central axis substantially normal to the surface of the connecting block on which it is disposed. The spline is disposed on the internal wall with its longitudinal axis substantially parallel to the central axis of the circular socket. The circular socket is configured to be coupled to a cylindrical deformable rod having a central axis and two opposing ends. In use, one deformable end is forced into the circular socket such that the deformable end deforms to accommodate the spline by forming a groove. In its inserted state, the cylindrical deformable rod is disposed substantially coaxial with the circular socket and rotational relationship between the circular socket and the cylindrical deformable rod is prevented.

The spline is configured to be removable using a reamer. Upon removing the spline, the circular socket is a mere circular through hole which is able to receive a cylindrical deformable rod and allow it to rotate freely within the socket.

The assembly further includes a stopper having a channel, a thumb hold and a ridge, wherein the channel is defined by a lengthwise portion of a cylinder and includes a central axis. The ridge is disposed along an arc in a plane substantially perpendicular to the central axis of the channel. The thumb hold is opposingly disposed from the channel and used as a leverage to facilitate the removal of an installed rod from a channel. Similar to a connecting block, the stopper is also configured to be coupled to a cylindrical deformable rod. In use, the cylindrical deformable rod is forced into the channel such that the central axis of the cylindrical deformable rod is substantially parallel to the central axis of the channel and the cylindrical deformable rod deforms to form a groove to accommodate the ridge. In its inserted state, the cylindrical deformable rod is disposed substantially coaxial with the channel and sliding

relationship between the channel and the cylindrical deformable rod is prevented.

Accordingly, it is a primary object of the present invention to provide connecting blocks that cooperate with elementary rods to create a releasably engaged assembly.

It is another object of the present invention to provide stoppers that cooperate with elementary rods to create a releasably engaged assembly.

It is yet a further object of the present invention to provide connecting blocks which can be used both to releasably engage a rod in its unmodified form and also ones that can be used to support rotating rods with minor modification.

Whereas there may be many embodiments of the present invention, each embodiment may meet one or more of the foregoing recited objects in any combination. It is not intended that each embodiment will necessarily meet each objective. Thus, having broadly outlined the more important features of the present invention in order that the detailed description thereof may be better understood, and that the present contribution to the art may be better appreciated, there are, of course, additional features of the present invention that will be described herein and will form a part of the subject matter of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the manner in which the above-recited and other advantages and objects of the invention are obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

Figure 1 is a front perspective exploded view of a fastening assembly depicting the use of two virgin cylindrical deformable rods to releasably engage two connecting blocks. Figure 2 is a front orthogonal view of a connecting block and two fitted rods.

Figure 3 is a front perspective view of a first fastening assembly depicting the use of two cylindrical deformable rods to releasably engage two connecting blocks.

Figure 3A depicts a prior art rod and connecting block assembly.

Figure 3B depicts an assembly constructed from a plurality of prior art connecting blocks and rods.

Figure 4 is a partial front perspective view of a connecting block and a cylindrical deformable rod inserted into a socket of the connecting block.

Figure 5 is a partial front perspective view of a connecting block and a cylindrical deformable rod pulled out from a socket of the connecting block after getting releasably engaged to the socket.

Figure 6 is a partial front orthogonal view of a connecting block depicting a pair of sockets.

Figure 6A is a partial cross-sectional orthogonal view of a connecting block depicting a socket as taken along line C-C of Figure 6.

Figure 7 is a partial front orthogonal view of a connecting block depicting a second embodiment of a socket. Figure 7A is a partial orthogonal view of a connecting block depicting a socket having a pointed profiled spline pattern.

Figure 7B is a partial orthogonal view of a connecting block depicting a socket having a pointed profiled spline pattern.

Figure 7C is a partial orthogonal view of a connecting block depicting a socket having a polygonal profiled spline pattern.

Figure 7D is a partial orthogonal view of a connecting block depicting a socket having an aslant profiled spline pattern.

Figure 8 is a perspective view of a reamer and a connecting block depicting the use of the reamer to convert a socket into a through hole.

Figure 9 is a perspective view of a drill bit and a connecting block depicting the use of the drill bit to convert a socket into a through hole.

Figure 10 is a partial front perspective of a connecting block depicting a reamed socket.

Figure 11 depicts the use of a reamer on the assembly of Figure 3.

Figure 12 depicts the assembly of Figure 3 having two reamed sockets.

Figure 13 is a front perspective view of a second assembly depicting the use of a cylindrical deformable rod to releasably engage a gear.

Figure 14 is a front orthogonal view of the gear of Figure 13.

Figure 15 is a front perspective view of the fastening assembly of Figure 13 and the cylindrical deformable rod inserted in a socket of the gear.

Figure 16 is a front perspective view of a combination of the first and second assemblies depicting the second assembly being aligned to be inserted into the modified sockets of the first assembly.

Figure 17 is a front perspective view of a combination of the first and second assemblies depicting the mounting of the second assembly in the first assembly.

Figure 18 is a bottom perspective view of a stopper.

Figure 19 is a side orthogonal view of the stopper of Figure 18.

Figure 20 is a top perspective exploded view of a third assembly depicting the use of a cylindrical deformable rod to releasably engage a stopper.

Figure 21 is a top perspective exploded view of a third assembly depicting the insertion of the cylindrical deformable rod in the space between a channel and a thumb hold.

Figure 22 is a side orthogonal view of a third assembly depicting a mounted cylindrical deformable rod in the channel of the stopper.

Figure 23 is a top front perspective view of the assembly shown in Figure 22. Figure 24 is a top front sectional perspective view of the third assembly as taken along line A-A of Figure 22.

Figure 25 is a bottom orthogonal view of the third assembly as taken along line B-B of Figure 22.

Figure 26 is a top front perspective view of the third assembly depicting the cylindrical deformable rod being removed from the stopper.

Figure 27 is a top from perspective view of the third assembly depicting the cylindrical deformable rod having been removed from the stopper and the deformation resulted from having mounted the cylindrical deformable rod in the channel of the stopper.

Figure 28 is a front perspective view of a combination of the first and second

assemblies and a stopper of the third assembly depicting the use of a stopper to secure the second assembly and the stopper of the third assembly onto the first assembly. Figure 29 depicts another example of combining the first, second and third assemblies. Figure 30 is a top front perspective view of an alternate connecting block.

Figure 31 is a bottom rear perspective view of the alternate connecting block of Figure 30.

The drawings are not to scale, in fact, some aspects have been emphasized for a better illustration and understanding of the written description.

PARTS LIST

2 - connecting block

3 - socket opening

4 - socket

5 - internal wall of socket

6 - relief

7 - central axis of socket

8 - spline

9 - transverse cross-sectional area of spline

10 - rod

12 - reamer

14 - spline cutter

16 - handle

18 - deformable rod end

20 - fitted rod end 22 - gear

24 - alternate connecting block

26 - pointed profiled spline

28 - polygonal profiled spline

30 - aslant profiled spline

32 - reamed socket

34 - drill bit

36 - stopper

38 - installation guide

40 - channel

41 - diameter of channel

42 - ridge

43 - height of ridge

44 - direction in seating a rod to stopper

46 - impression or groove made in rod due to seating of rod to socket

48 - impression or groove made in rod due to seating of rod to stopper

50 - thumb hold

52 - force as applied using a thumb

54 - force as applied using a finger

56 - bevel angle of socket opening

58 - prior art rod

60 - prior art connecting block

62 - socket of prior art connecting block

64 - rod end of prior art connecting block

BEST MODE FOR CARRYING OUT THE INVENTION

Figure 1 is a front perspective exploded view of a fastening assembly depicting the use of two virgin cylindrical deformable rods 10 to releasably engage two connecting blocks

2. In this example, a pair of connecting blocks 2 and a pair of rods 10 are provided. In practice, a plurality of connecting blocks 2 and rods 10 can be combined to construct rather complex structures. The present fastening assembly provides versatile building blocks for constructing structures. Each cylindrical deformable rod 10 may be any dowel, stick, or otherwise featureless, elongated circular bar of suitable length. Rods

10 are provided in stock lengths of for example 8 feet, 6 feet, etc.. An end user selects a desired length and cuts a rod to the desired length using a pair of scissors, a knife or any sharp cutting tools. Contrary to conventional rods used in conventional toy sets, rods of the present invention are designed to be cut into suitable lengths without affecting the quality of joints that will result from the process of attaching rods to connecting blocks. Conventional rods are manufactured to fixed lengths such as 2 inches, 4 inches, and the like. Each of them further includes socket interfacing features which allow it to be attached to a mating socket. Modification to an end of such a conventional rod typically alters its functionality. In the present fastening assembly, an end user need not be concerned with the lengths of rods as rods of any reasonable lengths can be easily obtained. The applicant discovered that soft woods such as basswood, pine and poplar are suitable to be used as the rods. Other materials such as plastic may also be used, provided that the hardness of such material ranges from Rockwell R 50-130. In one embodiment, the rods 10 are provided in diameters of about 0.2 inches, although various other sizes may also be suitable. Connecting blocks 2 are preferably constructed from plastic having a hardness ranging from 40 to 90 Durometer (Shore) D, i.e., hardness exceeding that of a mating rod 10.

Figure 2 is a front orthogonal view of a connecting block 2 and two fitted rods 10.

Referring to Figures 1 and 2, each connecting block 2 includes a plurality of sockets 4. In this example, the sockets 4 are provided in pairs although it is unnecessary to do so as will be demonstrated elsewhere in the document. Each socket 4 is substantially circular. Although not required, each socket 4 is disposed perpendicularly to a surface of a connecting block 2. In each pair of sockets, a relief 6 is disposed between the sockets 4 to make inserting of a rod easier. As a rod 10 is forced into a socket 4, the relief 6 allows the socket 4 to temporarily deform to accommodate the rod 10. When insertion is complete, resilience of the socket material causes the socket to return to its original shape and size. Such deformation is also important to allow easy insertion and operation of a spline cutter or a drill bit 34. Alternatively, one or more individual reliefs 6 may be built into each socket 4. Figure 3 is a front perspective view of a first fastening assembly depicting the use of two cylindrical deformable rods 10 to releasably engage two connecting blocks 2. The rods 10 are cut to substantially similar length and each rod 10 is forced into a socket at one of its ends. Figure 4 is a partial front perspective view of a connecting block 2 and a rod 10 inserted into a socket 4 of the connecting block 2. Figure 5 is a partial front perspective view of a connecting block 2 and a rod 10 pulled out from a socket 4 of the connecting block 2 after getting releasably engaged to the socket 4. It shall be noted that the deformable rod end 18 deforms to form grooves 46 in order to conform to the splines 8 of the socket 4. As a result, the fitted/deformed end 20 of the rod 10 cooperates with the splines 8 to prevent relative rotation between them. In one embodiment, the maximum force required to mount a rod 10 to a socket is 10 lbs. In one embodiment, the minimum amount of force required to initiate sliding of a fitted rod 10 relative to its mating socket 4 is 2 lbs.

Figure 3A depicts a prior art rod 58 and connecting block 60 assembly. Figure 3B depicts an assembly constructed from a plurality of prior art connecting blocks 60 and rods 58. These are sample construction elements of toy construction set TINKERTOY ® marketed by Hasbro, Inc. As depicted in Figure 3A, the rod 58 includes a sprung rod end 64 having a flat cutout. The diameter of the rod end 64 is configured slightly larger than the socket 62. In order to install a rod 58 in the socket 62, the rod end 64 is compressed in the direction of the flat cutout to result in a smaller diameter so that it can be inserted into and friction fitted in the socket 62. Such installation lacks positive locking as a torque applied to the rod against the connecting block 60 can easily overcome the friction which holds the two parts together. In contrast, the combination of splines disposed in a socket of the present invention and the mating grooves formed on a rod as a result of forcing a rod against the splines provides positive locking to prevent relative rotational movement of the rod 10 and the connecting block 2 as shown in Figures 1 , 2 and 3.

Figure 6 is a partial front orthogonal view of a connecting block 2 depicting a pair of sockets 4. Each socket 4 includes an internal wall 5 and a central axis 7. In this example, six splines 8 are disposed symmetrically about the central axis 7 along the internal wall 5 in a star configuration. Each spline 8 is preferably configured such that its longitudinal axis is substantially parallel to the central axis 7 of the socket 4 along which it is disposed. It is not necessary to configure splines to the star configuration as depicted in Figure 6. Applicant discovered that by appropriately sizing the transverse cross-sectional area 9 of the splines with respect to the area of the socket opening 3, the rod 10 can be forced into the socket without undue force while providing the ability to axially retain the rod 10 and prevent rotational relationship between the rod 10 and the socket 4. The ratio of the transverse cross-sectional area of the splines to the area of the socket opening preferably ranges from 0.035 to 0.51. More preferably, this ratio ranges from 0.045 to 0.48. One example of the transverse cross-sectional area is the hatched area shown in Figure 7. The area of the socket opening is then the area bounded by the socket opening 3 of the same figure. The use of splines 8 is not limited to the pattern shown in Figure 6. In order to create suitable attachment to a socket, a rod diameter shall be appropriately sized. Preferably the ratio of the rod diameter to the socket opening diameter ranges from about 0.70 to 0.98 and the rod is inserted into the socket substantially coaxially with the socket. More preferably, the ratio is about 0.90. The relatively large difference between the diameter of the rod and the diameter of the socket opening relaxes the requirement for precise rod or socket dimensions, thereby reducing manufacturing costs and wastes.

Figure 6A is a partial cross-sectional orthogonal view of a connecting block depicting a socket as taken along line C-C of Figure 6. The socket opening is beveled to incline inwardly at an angle 56 of from 10 to 60 degrees from a plane of the socket opening towards the center of the socket. Such incline aids in focusing the effort of inserting a rod in the socket, thereby eliminating wasted effort due to misalignment of the rod with respect to the socket. Figure 7 is a partial front orthogonal view of another embodiment of a socket. In this embodiment, a relief is not provided. Various other spline profiles may also be used. Figures 7A, 7B, 7C and 7D are partial orthogonal views of a connecting block depicting a socket having a first pointed 26 profiled spline pattern, a second pointed 26 profiled spline pattern, a polygonal 28 profiled spline pattern and an aslant 30 profiled spline pattern respectively.

Figure 8 is a perspective view of a reamer and a connecting block depicting the use of the reamer to convert a socket into a through hole. Contrary to conventional sockets, the present sockets are configured to be dual-use. On the one hand, each socket is designed to releasably engage a rod while on the other hand it can be converted to a through hole to allow the same rod to penetrate and be supported by its connecting block. As shown in Figure 8, a reamer 12 having a spline cutter 14 and a handle 16 is used to remove splines of a socket or to de-feature the socket. The handle 16 can be any bar or rod that is sized for grip with the palm of a hand and is secured to the spline cutter 14. In use, the reamer 12 may be inserted manually towards a socket while coupled with a twisting motion at the handle 16 to progressively cut and remove the splines of the socket. In another instance as depicted in Figure 9, a traditional drill bit may also be used to remove splines. Figure 10 is a partial front perspective view of a connecting block 2 depicting a reamed socket 32. As shown, the reamed socket lacks splines and therefore allows insertion of a rod. Each spline spans a circumference portion of the circumference of an opening of a socket. In one embodiment, the ratio of the total length encompassed by circumference portions of splines to the circumference of the opening on which the splines are disposed preferably does not exceed 0.7 such that the splines are easily removed in order to convert the socket to a smooth through hole.

As another example of the use of a reamer, Figure 11 depicts the use of a reamer on the assembly of Figure 3. Figure 12 depicts the assembly of Figure 3 having two reamed sockets in anticipation to receive a rod.

Figure 13 is a front perspective view of a second assembly depicting the use of a cylindrical deformable rod to releasably engage a gear 22. Figure 14 is a front orthogonal view of the gear of Figure 13. There is a total of five sockets and the sockets of the gear are similar in concept to the sockets shown earlier. However, two reliefs are applied to the central socket of the gear and the remaining sockets lack any relief. Figure 15 is a front perspective view of the fastening assembly of Figure 13 and the cylindrical deformable rod inserted in a socket of the gear, resulting in a plurality of grooves 46 on the end of the rod 10 which has been forced through the socket. As shown in Figure 15, the socket is installed at a position farther removed from a rod end. In a conventional construction toy set, only rod ends are configured to be inserted in a socket. Therefore, each conventional rod may not be inserted beyond its ends.

However a rod 10 of the present invention can be inserted in a present socket as far as desired. Figure 16 is a front perspective view of a combination of the first and second assemblies depicting the second assembly being aligned to be inserted through the de- splined sockets of the first assembly. Figure 17 is a front perspective view of a combination of the first and second assemblies depicting the mounting of the second assembly in the first assembly. The rod on which the gear is attached is configured to rotate freely within the de-splined sockets. In order to prevent this rod from getting detached, it needs to be secured with a stopper.

Figure 18 is a bottom perspective view of a stopper 36 which may be used to secure the second assembly to the first assembly. Figure 19 is a side orthogonal view of the stopper 36 of Figure 18 depicting the direction 44 in which a rod is seated in the channel 40. An installation guide 38 connects the thumb hold 50 to the channel 40 to aid in guiding the rod 10 for insertion into the channel 40 from the opening created between the thumb hold 50 and the channel 40. The stopper 36 includes a channel 40, a thumb hold 50 and a ridge 42, wherein the thumb hold 50 is opposingly disposed from the channel 40. The channel 40 is defined by a lengthwise portion of a cylinder having a central axis. The ridge is disposed along an arc in a plane substantially perpendicular to the central axis of channel 40. Figure 20 is a top perspective exploded view of a third assembly depicting the use of a cylindrical deformable rod to releasably engage a stopper 36. Figure 21 is a top perspective exploded view of a third assembly depicting the insertion of the cylindrical deformable rod 10 in the space between a channel 40 and a thumb hold 50. Figure 22 is a side orthogonal view of a third assembly depicting a mounted cylindrical deformable rod 10 in the channel 40 of the stopper 36. Figure 23 is a top front perspective view of the assembly shown in Figure 22. The rod 10 is configured to be releasably engaged to the stopper 36 by forcing the rod 10 into the channel 40 such that the rod 10 deforms to accommodate the ridge 42 and the rod is substantially coaxial with the channel 40 and sliding relationship between the rod 10 and the channel 40 is prevented. In one embodiment, the maximum force required to secure a cylindrical deformable rod to a stopper is 10 lbs.

The applicant discovered various factors affecting the performance of the stopper 36. As the transverse cross-sectional area of the ridge 42 is increased, the ridge 42 becomes more able in preventing sliding of the rod 10 with respect to the channel 40. As the diameter of the channel 40 increases, the ridge 42 becomes less able in preventing sliding of the rod 10 with respect to the channel. As the height 43 of the ridge 42 increases, the ridge 42 becomes more able in preventing sliding of the rod with respect to the channel. Preferably, the ratio of the height ^Λ 2 (square of height 43) of ridge to the transverse cross-sectional area of the ridge ranges from 0.66 to 8. Figure 24 is a top front sectional perspective view of the third assembly as taken along line A-A of Figure 22. Figure 25 is a bottom orthogonal view of the third assembly as taken along line B-B of Figure 22. It is evident that the rod 10 deformed to

accommodate the ridge 42 and the relative sliding movement between the rod 10 and channel 40 is ceased. Although not desired or designed in such a way, relative rotational movement between the rod 10 and the channel 40 is not prevented.

Figure 26 is a top front perspective view of the third assembly depicting the cylindrical deformable rod 10 being removed from the stopper 36. Figure 27 is a top front perspective view of the third assembly depicting the cylindrical deformable rod 10 having been removed from the stopper 36 and the deformation resulted from having mounted the cylindrical deformable rod 10 in the channel 40 of the stopper. It should be noted that a groove 48 developed on a portion of the rod 10 as a result of lodging the rod 10 in the channel 40.

Figure 28 is a front perspective view of a combination of the first and second assemblies and a stopper of the third assembly depicting the use of the stopper to secure the second and third assemblies onto the first assembly. The stopper prevents the second assembly from dislodging from the second assembly while allowing the rod of the second assembly to rotate freely within the reamed sockets 32. Figure 29 depicts another example of combining the first, second and third assemblies.

Figure 30 is a top front perspective view of an alternate connecting block 24. Figure 31 is a bottom rear perspective view of the alternate connecting block 24 of Figure 30. As illustrated herein, the previously disclosed rod and socket concept can be applied to blocks or components of other sizes and shapes. In this example, two parallelly disposed sockets are disposed about a central socket that is disposed perpendicularly to the two parallel sockets. This configuration enables extension of the structure in a new dimension. Each of the parallel sockets further includes a relief.

INDUSTRIAL APPLICABILITY

The present fastening assembly enables the use of stock or elementary rods for constructing toys. Rather than being premanufactured to specified lengths, stock rods are simply cut to desired lengths by users during use to suit particular purposes. This provides a manufacturing advantage in that the stock rods may be provided at a lower cost due to a fewer number of steps required to construct such rods where the stock rods are merely machined into feature deficient rods. Further, a user of the present invention need not be concerned with stocking rods of various fixed lengths to anticipate potential usage, thereby reducing the cost associated with storage or logistics management of the rods. In one preferred embodiment, the rods are constructed from a natural wood material which is biodegradable and recyclable as compared to plastic or metal materials which are traditionally used for such rods. The present invention enables versatile positioning of a socket along the length of a rod. A connecting block is forced to slide along the length of the rod to a desired position. In contrast to prior art rods whose end portions are configured to interface with sockets, the present rods and sockets are designed to allow sockets to be installed at a position farther removed from a rod end. As a result of such versatility, a more sophisticated structure can be built with the present rods and connecting blocks which otherwise requires purpose built building blocks, rods or other interfaces.

Sockets having tapered through holes that are commonly used to temporarily secure rods. In contrast, by disposing a plurality of splines within a socket having an opening with a final usable diameter, the required force to enable rod rotation in the socket of the present invention is significantly less than the amount of force required of sockets having tapered through holes due to the availability of the opening already having the final usable diameter. Further, a rod can be positively secured against rotation within the spline equipped socket of the present invention. In the case of a tapered through hole, slight relative axial movement between the socket and the rod causes the socket- rod engagement to fail.

Each socket opening is configured to incline inwardly toward the center of the socket. Such incline serves as a guide to focus or center the effort of inserting a rod in the socket, thereby eliminating wasted effort due to misalignment of the rod against the socket.

The requirement for a precise rod end is relaxed with the use of splines. Unlike tapered sockets, the relatively large difference between the diameter of a rod and the diameter of a socket relaxes the requirement for rods or sockets of precise dimensions, thereby reducing manufacturing costs and wastes.

The sockets of the present invention are designed to be dual-use. The connecting blocks can be used both to releasably engage a rod in its unmodified form. The connecting blocks can also be used to support one or more rotating rods with minor modification to their sockets. The target socket clearance for receiving and supporting a rod is achievable by mere removal of splines from each socket.