Abstract:
A trailer hitch system for equalizing trailer loads and reducing trailer sway. The trailer hitch system may include spring bars that may extend from a hitch head. The spring bars may be attached to the trailer using rigid brackets that reduce swinging of the spring bars. The rigid brackets may include an upward extending portion for attaching to the trailer tongue, and a lateral extending portion for receiving the spring bars thereupon. Pins may be utilized to secure the spring bars on the lateral extending portion of the brackets. The pins may each include a spring loaded clip that is rotatably between an unlocked position and a locked position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/768,316, filed Feb. 22, 2013, which is hereby incorporated by reference herein in its entirety, including but not limited to those portions that specifically appear hereinafter, the incorporation by reference being made with the following exception: In the event that any portion of the above-referenced provisional application is inconsistent with this application, this application supercedes said above-referenced provisional application. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable. 
       BACKGROUND 
       [0003]    1. The Field of the Invention 
         [0004]    The present disclosure relates generally to trailer hitch systems, and more particularly, but not necessarily entirely, to trailer hitch systems for reducing trailer sway. 
         [0005]    2. Description of Related Art 
         [0006]    Various different types of trailer hitches are known in the art for attaching trailers to towing vehicles. One of the most common types of towing systems utilizes a ball hitch. Typical ball hitches have a generally spherical shaped ball with a stem or threaded rod extending from a base of the ball. The threaded rod may be configured to engage a hitch head mounted on the towing vehicle using a threaded receiver or ball hitch fitting. A trailer coupling member, positioned on a front of the trailer tongue, may engage the ball hitch in a loose friction fit, and may be secured to the ball in preparation for towing. 
         [0007]    One of the biggest safety concerns with towing trailers is that the trailers may sway, leading to loss of control of the towing vehicle. A number of factors may contribute to sway, including: side winds, passing vehicles, quick lane changes, uneven roads and sudden stops. Some trailer hitches may not handle these situations well and may often exacerbate the sway problem making driving even more stressful and difficult. 
         [0008]    Another common problem encountered when towing a trailer is highway hop, or the bouncing that often happens to trailers on uneven roadways. This problem may be caused by uneven weight distribution. With ordinary ball-type hitches, most of the trailer tongue weight may be carried on the back axle of the tow vehicle. This may raise the front end of the tow vehicle. The uneven distribution of weight may make steering control more difficult, especially during emergency situations. Weight distribution allows a trailer and tow vehicle to be level. Risks associated with driving a trailer without a weight distribution hitch may include loss of steering control, braking difficulties, and hitch dragging. 
         [0009]    Some hitches include load equalizing systems utilizing spring arms or bars to distribute loads and allow the towing vehicle and trailer to remain level. One end of the spring arms may be attached under the ball hitch and hitch head. The spring arms may extend from the hitch head towards the trailer, and may be joined to the trailer tongue using chains and/or brackets. The end of the spring arms opposite the hitch head may be lifted or loaded to place an upward force on the hitch head to thereby equalize the load exerted on the trailer hitch. Various mechanisms are known for use in association with a trailer hitch to reduce side sway of the trailer as well as to equalize loads. Some prior art embodiments of the brackets for joining the spring bars to the trailer tongue have been formed as rigid members or brackets. An L-shaped pin is often utilized to secure the spring bars onto the brackets. 
         [0010]    Referring now to  FIG. 1 , a side view is shown of a towing vehicle  10  towing a trailer  12  with a trailer hitch  14 . It will be understood that the towing vehicle  10  may be any variety of vehicle known in the art, such as a truck, tractor or car, or any other variety of on-road or off-road vehicle, for example. Likewise, the principles of the present disclosure may be utilized with any variety of trailer  12  known in the art, such as camping trailers, boat trailers or cargo trailers, for example. 
         [0011]    As is known in the art, the load from the trailer  12  may force the rear end of the towing vehicle  10  down and raise the front end of the towing vehicle  10 . The uneven distribution of weight may make steering the towing vehicle  10  more difficult and may cause braking difficulties or the prior art hitches to drag on the ground. Load equalizing systems may be used to distribute the load created by the trailer  12  on the towing vehicle  10  to thereby make the trailer  12  and towing vehicle  10  more level, as shown in  FIG. 1 . 
         [0012]    As shown in  FIG. 2 , the trailer  12  may include a tongue  16  extending at a forward end of the trailer  12 . A coupler  18  may be located on an end of the tongue  16  for receiving a ball  20  of the hitch  14 , in a manner known in the art. The ball  20  may be disposed on a hitch head  22  which may be attached to the tow vehicle  10  through a connector  24 . A spring bar  26  may be joined to the hitch head  22  at one end, and to the trailer tongue  16  at an opposing end portion using a bracket  28 . It will be understood that two spring bars  26  may be used, one on each side of the trailer  12 . The spring bars  26  may be configured to provide an upward force on the hitch head  22  to equalize the distribution of the load and allow the towing vehicle  10  and trailer  12  to be more level. The spring bars  26  may also be beneficial for reducing sway of the trailer  12 . 
         [0013]    Referring now to  FIG. 3 , a perspective view is shown of one embodiment of the prior art hitch system. It will be understood that the hitch system  14  may be attached to the tow vehicle  10  and trailer  12  as shown in  FIG. 1 , using mounting assemblies  40 . The hitch  14  may include the hitch head  22  for receiving the ball  20 . It will be understood that the ball  20  may be attached to a trailer  12  in a manner known in the art. Similarly, the hitch  14  may include a connector  24  for attachment to a tow vehicle  10 . 
         [0014]    The hitch  14  may include spring bars  26  for applying an upward force on the hitch head  22  as discussed above. It will be understood that the spring bars  26  may be formed in various different configurations in accordance with the principles of the present disclosure. For example, one embodiment of the spring bars  26  may be formed of elongate members having a rectangular cross-sectional shape. The spring bars  26  may have various different configurations. 
         [0015]    As mentioned, the free ends of the spring bars  26  may be supported by brackets  28 . The brackets  28  may be mounted to the tongue of a trailer. The brackets  28  may each include an L-shaped member  30 . Each of the L-shaped members  30  may include a vertical portion  32  and a horizontal portion  34 . The free ends of the spring bars  26  may be loaded onto the horizontal portions  34  of the L-shaped members  30 . 
         [0016]    Inverted L-shaped pins  36  may be utilized to secure the spring bars  26  onto the horizontal portions  34 . In particular, the L-shaped pins  36  may include a short leg  36 A and a long leg  36 B. The long legs  36 B of the pins  36  may be inserted into pin receiving holes in the horizontal portions of the brackets  28 . Spring clips  38  inserted through retaining holes  39  in the long legs  36 B may prevent the pins  36  from falling out. 
         [0017]    The use of the spring clips  38  to secure the pins  36  have several drawbacks. First, spring clips  38  are difficult to install because the retaining holes  39  are typically only 12 to 18 inches off of the ground. That is, the retaining holes  39  are out of sight causing a user to have to stoop or kneel down to see the retaining holes  39  and align the clip  38  with the holes  39 . Second, because of the proximity of the retaining holes  39  to the horizontal portions  34  of the L-shaped members  30 , users often hit the portions  34  when installing the clips  38 . Third, the bent portion of the pins  36  may undesirably rest on the spring bars  26 . Lastly, the use of the pins  36  may cause loud clattering due to road vibrations. 
         [0018]    Thus, despite the advantages of the known trailer hitches, improvements are still being sought. The prior art is characterized by several disadvantages that may be addressed by the present disclosure. The present disclosure minimizes, and in some aspects eliminates, the failures of the prior art, by utilizing the methods and structural features described herein. 
         [0019]    The features and advantages of the disclosure will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by the practice of the disclosure without undue experimentation. The features and advantages of the disclosure may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    The features and advantages of the disclosure will become apparent from a consideration of the subsequent detailed description presented in connection with the accompanying drawings in which: 
           [0021]      FIG. 1  is a side view of a tow vehicle towing a trailer using a trailer hitch, as known in the prior art; 
           [0022]      FIG. 2  is a side view of one embodiment of a trailer hitch attached to a break-away portion of a trailer tongue, as known in the prior art; 
           [0023]      FIG. 3  is a perspective view of a trailer hitch in accordance with the principles of the present disclosure, as known in the prior art; 
           [0024]      FIG. 4  is a side view of a pin with a clip in an unlocked position according to an embodiment of the present disclosure; 
           [0025]      FIG. 5  is a side view of a pin with a clip in an intermediate position according to an embodiment of the present disclosure; 
           [0026]      FIG. 6  is a side view of a pin with a clip in a locked position according to an embodiment of the present disclosure; 
           [0027]      FIG. 7  is a perspective view of a pin with a clip in an intermediate position according to an embodiment of the present disclosure; 
           [0028]      FIG. 8  is a top view of a pin with a clip in an intermediate position according to an embodiment of the present disclosure; 
           [0029]      FIG. 9  depicts a bracket assembly mounted to a trailer tongue and a pin with a clip in an unlocked position according to an embodiment of the present disclosure; and 
           [0030]      FIG. 10  depicts a bracket assembly mounted to a trailer tongue and a pin with a clip in an unlock position according to an embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    For the purposes of promoting an understanding of the principles in accordance with the disclosure, 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 disclosure is thereby intended. Any alterations and further modifications of the inventive features illustrated herein, and any additional applications of the principles of the disclosure as illustrated herein, which would normally occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the disclosure claimed. 
         [0032]    Before the present structures and methods for providing a sway control hitch are disclosed and described, it is to be understood that this disclosure is not limited to the particular configurations, process steps, and materials disclosed herein as such configurations, process steps, and materials may vary somewhat. It is also to be understood that the terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting since the scope of the present disclosure will be limited only by the appended claims and equivalents thereof. 
         [0033]    It must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Moreover, as used herein, the terms “comprising,” “including,” “containing,” “characterized by,” and grammatical equivalents thereof are inclusive or open-ended terms that do not exclude additional, unrecited elements or method steps. 
         [0034]    Referring now to  FIGS. 4-8 , there is depicted an embodiment of a pin  100  for securing a spring bar extending from a hitch head to a horizontal support member  35  (see FIG.  3 ) of, or extending from, a trailer frame. The pin  100  may comprise a shaft member that may include long leg  102  and a short leg  104 . The long leg  102  and the short leg  104  may meet at approximately a ninety-degree angle such that the pin  100  forms an inverted L-shaped. In an embodiment, the shaft member may have a rectangular cross section. In an embodiment, the shaft member may have a circular cross section or any other shaped cross section. 
         [0035]    A rotating spring clip or clip member  106  may be coupled to the long leg  102  of the pin  100 . In particular, as perhaps best observed in  FIG. 8 , the clip  106  may be hooped shaped and may include a frame  109  that defines an open interior or aperture  111 . The frame  109  may include a first side  106 A, a second side  106 B, a third side  106 C, and a fourth side  106 D. The first side  106 A and the second side  106 B may be opposing and parallel to each other. The third side  106 C and the fourth side  106 D may be opposing and parallel to each other. 
         [0036]    In addition, the frame  109  may extend between a first terminal end  120  and a second terminal end  122 . The first terminal end  120  and the second terminal end  122  may be located on the second side  106 B of the frame  109 . The first terminal end  120  and the second terminal end  122  may be separated by a small gap. 
         [0037]    In an embodiment, a first bore  110  may extend into a first sidewall  112  of the pin  100 . A second bore  114  may extend into a second sidewall  116  of the pin  100 . The first sidewall  112  and the second sidewall  116  may be disposed on opposite, lateral sides of the long leg  102  of the pin  100 . The first terminal end  120  of the clip  106  may be disposed in the first bore  110  and the second terminal end  122  of the clip  106  may be disposed in the second bore  114 . The resilient nature of the clip  106  may secure the first end  120  and the second end  122  in their respective bores. As can be observed in  FIG. 8 , in an embodiment, the axes of the bores  110  and  114  may be offset horizontally. In an embodiment, the axes of the bore  110  (shown by a dashed line) and bore  114  may be offset vertically as seen in  FIG. 5 . In an embodiment, the axes of the bores  110  and  114  may be offset from each other both vertically and horizontally, or in a first direction and a second direction. 
         [0038]    In an embodiment, the clip  106  may be substantially rectangular in shape. In an embodiment, the clip  106  may be hooped shaped. In an embodiment, the clip  106  may be circular shaped. In an embodiment, the clip  106  may include an optional finger loop as shown by the dashed lines  124  in  FIG. 8 . 
         [0039]    Referring now to  FIGS. 4 ,  5  and  6 , the clip  106  may be operable between an unlocked position as shown in  FIG. 4  and a locked position as shown in  FIG. 6 .  FIG. 5  depicts an intermediate position for the clip  106 . In particular, the clip  106  may rotate between the unlocked position and the locked position as shown by the arrows in  FIG. 5 . The resilient nature of the clip  106  and the offset of the bores  110  and  114  may cause to clip  106  to remain in the unlocked position or the locked position. In this regard, the clip  106  may include a spring feature that maintains the clip  106  in the unlocked position or the locked position. The spring feature may be caused by the vertical and/or horizontal offset of the bores  110  and  114 . 
         [0040]    Referring now to  FIG. 9 , there is shown a bracket assembly  150  mounted to a tongue  152  of a trailer (not shown). The bracket assembly  150  may include an L-shaped support member  154  (also referred to herein as a “spring bar support member”) having a vertical portion  156  and a horizontal portion  158 . The horizontal portion  158  may include an upper surface  160  that provides a support for a spring bar  162 . Extending through the horizontal portion  158  may be a pin hole  164 . 
         [0041]    Installed in the pin hole  164  may be the pin  100 . In particular, the long leg  102  of the pin  100  may be disposed in the pin hole  164 . The clip  106  may abut against the upper surface  160  of the horizontal portion  158  to thereby define the limit of the progress of the long leg  102  through the pin hole  164 . That is, the clip  106  prevents the pin  100  from dropping through the pin hole  164 . As can be observed, the clip  106  is positioned in the unlocked position when the long leg  102  of the pin  100  is installed into the pin hole  164 . 
         [0042]    Referring now to  FIG. 10 , where like reference numerals depict like components, there is depicted the clip  106  in the locked position. As can be observed, in the locked position, the clip  106  passes over the horizontal portion  158  of the L-shaped member  154 . The horizontal portion  158  then serves as a stop to engage an end member or stop portion  107  of the clip  106  to thereby prevent the pin  100  from disengaging the pin hole  164 . 
         [0043]    It will be appreciated that although the pin  100  is shown as an inverted L-shaped, that the pin  100  may be some other shape. In an embodiment, the pin  100  may be substantially straight. In an embodiment, the pin  100  may be curved or rounded. 
         [0044]    Referring to  FIGS. 4 and 10 , a distance, D, between the mounting bores for the clip  106  and the horizontal leg  104  of the pin  100  may be greater than 1.5 inches, or between 1.0 and 2.0 inches. Thus, the horizontal leg  104  may not contact the spring bar  162  because the clip  106  may abut against the upper surface  160  of the horizontal portion  158  of the L-shaped member  154 . It will be appreciated that this feature reduces noise as any contact between a pin and a spring arm may produce chattering as the spring arm moves forward and backward while the tow vehicle is in motion. 
         [0045]    Referring back to  FIG. 8 , a width, W, of the opening defined by the clip  106  may be about 1.375 inches, or between 0.75 and 1.75 inches. A length, L, of the opening defined by the clip  106  may be about 2.25 inches, or between 1.75 and 2.75 inches. It will be appreciated that there is criticality to the width, W, of the opening defined by the clip  106 . In particular, the width, W, allows the pin  100  to rise up when the spring arm pushes on the pin  100 . This can happen during a turn or when traveling on uneven terrain. Further, the width, W, allows the clip  106  to clear the edge of the horizontal portion  158  of the L-shaped member  154 . In an embodiment, the clip  106  may define a bail. 
         [0046]    An embodiment of a trailer hitch system according to the present disclosure comprises: 
         [0047]    a spring bar joined with a hitch head and exerting a force on said hitch head;
       a bracket for joining said spring bar to a trailer, said bracket having a horizontal portion having a pin receiving hole formed therein, the horizontal portion forming a spring bar support surface;       
 
         [0049]    a pin having an elongated portion removably insertable into said pin receiving hole; and 
         [0050]    a clip mounted to said pin, the clip having an elongated portion; 
         [0051]    wherein said clip is rotatably operable between a locked position and an unlocked position;
       wherein the elongated portion of the clip is disposed under the horizontal portion when the clip is in the locked position;       
 
         [0053]    wherein the elongated portion of the clip is disposed above the horizontal portion when the clip is in the unlocked position. 
         [0054]    The above disclosed embodiment, wherein the clip forms a stop that limits a distance that the elongated portion of the pin extends through the pin receiving hole. 
         [0055]    The above disclosed embodiment, wherein the clip comprises a contiguous, elongated body member that extends between a first end and a second end. 
         [0056]    The above disclosed embodiment, wherein the body member defines a bail. 
         [0057]    The above disclosed embodiment, wherein the first end and the second end of the clip are mounted in bores disposed on opposing sides of the pin. 
         [0058]    The above disclosed embodiment, wherein axes of the bores are offset from each other. 
         [0059]    The above disclosed embodiment, wherein a width of an aperture defined by the clip is about 1.375 inches. 
         [0060]    The above disclosed embodiment, wherein a length of an aperture defined by the clip is about 2.25 inches. 
         [0061]    The above disclosed embodiment, wherein the clip comprises a finger loop. 
         [0062]    The above disclosed embodiment, wherein the pin is straight. 
         [0063]    The above disclosed embodiment, wherein the pin forms an inverted L-shape. 
         [0064]    The above disclosed embodiment, wherein an axis of rotation of the clip is perpendicular to a longitudinal axis of the elongated portion of the pin. 
         [0065]    The above disclosed embodiment, wherein a portion of the clip abuts against the spring bar support surface of the horizontal portion to limit a distance that the elongated portion extends through the pin receiving hole. 
         [0066]    An embodiment of the present disclosure may include n apparatus for use in securing a spring arm to a bracket assembly attached to a trailer tongue, said apparatus comprising a shaft member having a first bore and a second bore formed therein; a clip member defining a bail, the bail extending between a first terminal end to a second terminal end; wherein the first terminal end of the bail is disposed in the first bore and the second terminal end of the bail is disposed in the second bore; wherein the bail of the clip member is operable between an unlocked position and a locked position. 
         [0067]    In an embodiment, the first bore and the second bore are offset from each other in a first direction. In an embodiment, the first bore and the second bore are offset from each other in a second direction. In an embodiment, a cross-section of the shaft member is one of rectangular, square and circular. In an embodiment, the shaft member comprises an inverted L-shaped having a long leg and a short leg. In an embodiment, the shaft member consists of a straight leg only. In an embodiment, the first bore and the second bore are formed in opposite sides of the long leg. In an embodiment, the clip member comprises a spring feature to maintain the clip member in the locked position. In an embodiment, the clip member comprises a spring feature to maintain the clip member in the unlocked position. 
         [0068]    An embodiment of the present disclosure may comprise bracket assembly for supporting a spring bar extending from a hitch head, said bracket assembly comprising: a spring bar support member; a mounting assembly for mounting the spring bar support member to a trailer frame; a pin hole formed in the spring bar support member; a pin having a shaft member configured and dimensioned to be installed in the pin hole; and a clip member rotatably mounted to the shaft member, the clip member defining a stop portion; wherein the clip member is operable between a locked position and an unlocked position; wherein the stop portion of the clip member is positioned above the spring bar support member when the clip member is in the unlocked position and the pin is installed in the pin hole; wherein the stop portion of the clip member is positioned below the spring bar support member when the clip member is in the locked position and the pin is installed in the pin hole. 
         [0069]    In an embodiment, the clip member limits a depth of the pin in the pin hole. In an embodiment, the shaft member of the pin comprises a first bore and a second bore formed therein, wherein the clip member defines a bail, the bail extending between a first terminal end to a second terminal end, wherein the first terminal end of the bail is installed in the first bore of the shaft member and the second terminal end of the bail is installed in the second bore of the shaft member. In an embodiment, the first bore and the second bore are offset from each other in a first direction. In an embodiment, the first bore and the second bore are offset from each other in a second direction. In an embodiment, a cross-section of the shaft member is one of rectangular, square and circular. In an embodiment, the shaft member comprises one of an inverted L-shape having a long leg and a short leg and a straight leg. It will be appreciated that the shaft member may comprise any other shape. In an embodiment, the first bore and the second bore are formed in the long leg. In an embodiment, the first bore and the second bore are formed in opposite sides of the long leg. In an embodiment, the clip member comprises a spring feature to maintain the clip member in the locked position. 
         [0070]    An embodiment of the present disclosure may comprise a trailer hitch assembly comprising: a spring bar joined with a hitch head and exerting a force on said hitch head; a bracket assembly for joining said spring bar to a trailer tongue, said bracket assembly having a horizontal portion having a pin receiving hole formed therein, the horizontal portion defining a spring bar support surface; a pin having a shaft member removably insertable into said pin receiving hole; and a clip member rotatably mounted to said pin, the clip member defining a stop portion; wherein said clip member is operable between a locked position and an unlocked position; wherein the stop portion of the clip member is disposed under the horizontal portion when the clip member is in the locked position; wherein the stop portion of the clip member is disposed above the horizontal portion when the clip member is in the unlocked position; wherein the clip member limits a distance that the shaft member of the pin extends through the pin receiving hole; wherein the clip member comprises a contiguous, elongated bail that extends between a first terminal end and a second terminal end; wherein the first terminal end and the second terminal end of the clip member are disposed in bores formed on opposing sides of the pin, each of the bores having an axis; wherein axes of the bores are offset from each other in a first direction and a second direction; wherein a width of an aperture defined by the bail of the clip member is about 1.375 inches; wherein a length of the aperture defined by the bail of the clip member is about 2.25 inches; wherein the clip member comprises a finger loop; wherein the shaft member of the pin defines an inverted L-shape; wherein a portion of the clip member abuts against the spring bar support surface of the horizontal portion to limit a distance that the shaft member extends through the pin receiving hole; wherein the clip member comprises a spring feature to maintain the clip member in the locked position. 
         [0071]    Those having ordinary skill in the relevant art will appreciate the advantages provided by the features of the present disclosure. For example, it is a feature of the present disclosure to provide a trailer hitch system that is relatively simple in design and manufacture. Another feature of the present disclosure is to provide such a trailer hitch system that reduces trailer sway and equalizes loads. It is a further feature of the present disclosure, in accordance with one aspect thereof, to provide a trailer hitch system having brackets. It is an additional feature of the present disclosure to provide a trailer hitch system having pins with clips for securing the spring arms. It is an additional feature of the present disclosure to provide a trailer hitch system having L-shaped pins for securing the spring arms. It is an additional feature of the present disclosure to provide a trailer hitch system having pins with retaining clips for securing the spring arms. It is an additional feature of the present disclosure to provide a trailer hitch system having pins with retaining clips with finger loops for securing the spring arms. 
         [0072]    In the foregoing Detailed Description, various features of the present disclosure are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description of the Disclosure by this reference, with each claim standing on its own as a separate embodiment of the present disclosure. 
         [0073]    It is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present disclosure. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present disclosure and the appended claims are intended to cover such modifications and arrangements. Thus, while the present disclosure has been shown in the drawings and described above with particularity and detail, it will be apparent to those of ordinary skill in the art that numerous modifications, including, but not limited to, variations in size, materials, shape, form, function and manner of operation, assembly and use may be made without departing from the principles and concepts set forth herein.