Abstract:
A lever assembly is disclosed which is formed from a one piece, longitudinally oriented, hollow metal tubular member integrally formed with a first end, a second end, and a central section in between. A clevis is integrally formed in the first end. The clevis portion has a pair of spaced apart walls and an integral projection extending from each of the spaced apart walls. Additionally, the assembly has an integrally formed foot engaging portion extending from the second end.

Description:
This application claims the benefit of Provisional Application No. 60/155,999, filed Sep. 24, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention is directed to a control lever assembly for a vehicle, and more particularly to using a hydroformed tubular member. 
     Lever assemblies are used in conventional motor vehicles for brakes, clutches, accelerators and emergency brakes. Many of these lever constructions are fabricated assemblies and typically consist of a bent steel bar with apertures and bushings at one end for receiving a pin for pivotal attachment to the vehicle and a stamped sheet metal foot plate at the other end. A foot pad, bushing and bracketry are attached to the steel bar to form a fabricated assembly. Additionally, the lever assembly may have tabs welded to it for the actuation of switches, the attachment of return springs and other similar devices. Examples of lever assemblies are disclosed in U.S. Pat. Nos. 4,356,740, 5,044,223, and 5,078,024. These prior art assemblies are relatively heavy, complex and expensive to manufacture and require welding or equivalent joining operations which can reduce the durability and reliability of the lever assembly. 
     A lightweight pedal mechanism formed by hydroforming is disclosed in U.S. Pat. No. 5,435,205. The pedal mechanism is made from a single length of extruded, thin-walled, round cross-section aluminum tubing. It consists of an upper clevis portion, a central portion and a lower foot engaging section. The clevis section has opposed apertures for receiving a bushing. Directly above the aperture is a cut-out section in communication with the extreme end of the side walls and with the apertures in the side walls. The bushing has an outer diameter with grooves or notches. This prevents the bushing from moving out of the clevis section in a radial direction. The foot engaging section is formed from a lower section that is bent in a plane that is about at a right angle relative to the length of the main body portion. Because the foot engaging section extends at a right angle relative to the main body portion, the pedal is not compact. Also, the bushing must be inserted separately into the apertures in the clevis section. 
     This design has not been extensively adopted for motor vehicle use in spite of its purported advantages. Thus, there is still a need for an improved lever assembly that overcomes the limitations of the above design and provides a light-weight, inexpensive, compact, easy to manufacture, and integrated, longitudinally oriented lever assembly. 
     SUMMARY OF THE INVENTION 
     The present invention provides a lever assembly consisting of a one piece metal tubular member having an integrally formed first end, an integrally formed opposite second end, and an integrally formed center section between the first and second ends, a free end integrally formed of the second end and a clevis portion integrally formed within the first end. The clevis portion has a pair of spaced apart walls and an integral projection extending away from one of the pair of spaced apart walls. 
     It is an object of the present invention to provide a lever assembly which can be used for a variety of applications, including brakes, clutches, accelerator devices or emergency brakes in a vehicle, and which is light weight, inexpensive, easy to manufacture and integrates a jointless projection to receive and retain a bushing therein. 
     It is a further object of the present invention to provide a longitudinal lever assembly which is formed by hydroforming or a similar process and in which the integral projections are hydropierced to form an aperture which receives a bushing pin therein and which is inexpensive and easy to manufacture. 
     It is still a further object of the present invention to provide a longitudinal lever assembly with a central portion which has an integral projection and a structural configuration which permits the integration of switches, gauges, mounting devices or actuator rods and yet is easy and inexpensive to manufacture. 
     It is still another object of the present invention to provide a lever assembly with an integral projection and a pedal section with a pair of spaced apart portions forming a planar surface, an intermediate portion which is below the planar surface supporting the spaced apart portions and which is easy and inexpensive to manufacture. 
     These and other objects of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view illustrating the lever assembly of the present invention after it has been formed; 
     FIG. 2 is a frontal view of the lever assembly formed according to the present invention; 
     FIG. 3 is a side view of the lever assembly formed according to the present invention; 
     FIG. 4 is a frontal view of the foot pad taken along lines  4 — 4  of FIG. 3; 
     FIGS. 5 A-F are different cross-sectional views along lines  5 — 5  of FIG. 1; and 
     FIGS. 6 A-F are different cross-sectional views along lines  6 — 6  of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The lever assembly according to the present invention is designated by the numeral  100  as shown in FIGS. 1-6. The assembly  100  is made from a single length of an extruded, light weight, hollow, thin metal tubing  10 . Optionally, the tubing  10  is roll formed with a fused joint to produce a single, thin wall metal tubing of any exterior shape. The tubing  10  may be rectangular in exterior shape in cross-sectional view after hydroforming or, optionally, it is square  10   I , I-Beam  10   II , triangular  10   III , elliptical  10   IV , round  10   V , polygonal  10   VI , or any other similar outer wall or exterior shape after hydroforming that is satisfactory for the intended use. The tubing  10  is preferably made of steel, however, other metals such as aluminum, stainless steel alloy, magnesium, or other similar materials may also be used in practicing the present invention. 
     The tubing  10  is subjected to a hydroforming process which is well known to those skilled in the art. In the hydroforming process, hydraulic pressure above 0.5 MPa to 12 MPa pressure is applied to the inside of the tubing  10  to deform the walls of the tubing outwardly between mating surfaces of female die sections causing the tubing to take on the same configuration as that of the female dies and to feed the metal into a deformation zone to form integral parts of complex shapes. Such a process is shown in U.S. Pat. Nos. 5,435,205, 5,070,717 and 4,829,803. 
     The tubing  10  of the present invention has a central portion  20 , an upper portion  30 , and a foot engaging portion  40  which are formed along the longitudinal axis  60  as shown in FIGS. 1 and 2. The upper portion  30  and central portion  20  are formed by a generally parallel but spaced apart wall through its longitudinal axis length until just before the foot engaging portion  40  where the walls of the lower portion  36  are expanded, as will be discussed more fully below. Optionally, any one or more of the portions  20 ,  30 ,  40  may be offset from the longitudinal axis  60 . Those skilled in the art will appreciate that the preferred embodiment is described and illustrated herein as a parallel but spaced apart cross-section along the longitudinal axis  60 , as shown in the frontal view in FIG.  2 . The design requirements encountered in utilization of the lever assembly according to the invention may be satisfied with modifications to this cross-sectional configuration as dictated by the specific application to optionally include diverging and converging wall sections along its longitudinal axis  60 . 
     FIGS. 2 and 3 show the upper portion  30  having a pair of projections  32 ,  34  formed into the side walls  31 ,  33 , respectively, below the clevis section  35  of the tubing  10 . The projections  32 ,  34  are formed during the hydroforming process and optionally, could be hydropierced to form apertures  28 ,  29  in the projections  32 ,  34 , respectively. The apertures  28 ,  29  are preferably each formed with an inner round surface or, optionally, with a flat portion  27  or each is formed with other irregular inner shapes, such as elliptical  28   I ,  29   I , triangular  28   II ,  29   II , square  28   III ,  29   III , rectangular  28   IV ,  29   IV , or polygonal  28   V ,  29   V , to capture and provide orientation of the correspondingly outer surface shaped bushing pin member (not shown) when the bushing pin member is inserted therein. The projections  32 ,  34  also provide the bushing pin member with a substantial bearing surface which prevents deformation of the projections  32 ,  34  during use when the lever assembly is installed in a motor vehicle. The top  35  of the upper portion  30  receives a clevis section (not shown) which is connected to the appropriate control member (not shown). 
     In the upper portion  30 , shown in FIGS. 2 and 3, the tubing  10  is formed into a substantially rectangular, thin wall cross-sectional configuration. Below the projections  32 ,  34 , the central portion expands into an irregular shape in the side view, as shown in FIG. 3, while maintaining a spaced apart configuration in frontal view, as shown in FIG.  2 . The central portion  20  has an actuator aperture  22  formed by hydropiercing two opposite ends on the spaced apart walls of the central portion  20  to form round holes. Optionally, the aperture  22  may be formed into an irregular shaped undersurface to capture and provide orientation for an actuator pin  23 . The irregular shaped undersurface may also be an- inner diameter with a flat portion and, optionally, it may also include an elliptical, triangular, square, rectangular or polygonal shape. The central portion  20  also has contact surfaces  24 ,  25 ,  26  for mounting a device such as a switch, gauge or other monitoring unit as may be appropriate or required by the functions of the motor vehicle. The contact surfaces  24 ,  25  and  26 , respectively, generally have planar portions  21  formed therein. Those skilled in the art will appreciate that the lever assembly  100  may optionally have other openings or connection points formed therein as required by the application. 
     As stated previously, below the central portion  20  of the tubing  10 , the lower portion  36  is formed. The lower portion  36  is generally rectangular in cross-section in frontal view in FIG. 2, until the foot engaging portion  40 . However, the lower portion  36  may be tapered or have divergent or convergent shapes as required by the structural requirements of the lever assembly  100 . 
     As stated earlier, the foot engaging portion  40  which is part of the lower portion  36  is preferably formed by expanding the tubing  10  into a generally Y-shaped member  42 . The Y-shaped member  42  has a first portion  44  and a second portion  46  spaced apart from the first portion  46 . The first and second spaced apart portions  44 ,  46  form a flat planar portion  45 . An intermediate portion  48  is formed on the opposite side of the flat planar portion  45  but extends in a supporting manner to provide structural support to the first portion  44  and the second portion  46 , as shown in FIG.  3 . The first portion  44  and the second portion  46  are preferably parallel to each other as shown in FIG. 2, although they may optionally diverge or converge depending on the structural requirements of the application. The portions  44 ,  46  provide the required rigidity for an elastomeric foot engaging pedal pad  52 . The pedal pad  52  may be chemically engaged to the flat planar portion  45 , such as by adhesive processes well known in the art or other similar methods suitable for the application. Alternatively, a plurality of holes  41  are formed in the flat planar portion  45  for purposes of engaging the pedal pad  52  mechanically to the foot engaging portion  40  for example as when the pedal pad has pins or projections  54  which are molded into the pedal pad  52 . Those skilled in the art will recognize that the pins or projections  54  may be metal or plastic which, when inserted into the holes  41 , secure the pad  52  either during the chemical engagement process or mechanically engage the pad  58  to the portion  45  if the adhesive process is not required. Pins  54  are of conventional construction permitting insertion of conical engaging surfaces, referred to as “Christmas Tree” pins, which are conical in shape with several coextending branches or alternatively, other suitable fasteners, into the holes  41  so as to secure the pedal pad to the flat planar portion  45 . While the flat planar portion  45  is shown to be relatively smooth, alternatively, the portion  45  can be formed to include a plurality of regular surface ridges or a plurality of irregular surface ridges that frictionally engage the bottom of the operator&#39;s footwear during operation of the motor vehicle. 
     The dimensions of the finished product of the lever assembly  100 , as shown in FIGS. 1-6, will depend on the dimensions of the tubing  10  and the requirements of the application. The dimensions will be tailored to optimize the structural performance of the lever assembly  100  for the applied loads which are transferred into the lever assembly  100  during its operation. In certain applications, the lever assembly may used in conjunction with actuating switches, gauges and monitoring devices (not shown). For example, the surface area of the central portion  20  and upper portion  30  may be designed to provide an adequate contact surface for the actuation of a switch, such as a brake light switch, for its operation. 
     The lever assembly  100  is made from thin walled, extruded tubing which reduces or eliminates welded ancillary parts or secondary aperture forming operations. This results in a lever assembly that is less expensive to manufacture due to its fewer processing steps. 
     In operation, the lever assembly  100  of the present invention is installed in a vehicle (not shown), preferably in position similar to that shown in FIG.  2 . The hydroformed projections  32 ,  34  accept pivot bushing pin members in the apertures  28 ,  29 , respectively. The assembly  100  has a central portion  20  which extends toward the operator and a foot engaging portion  40  of the lower portion  36  which projects towards the operator. 
     Those skilled in the art will appreciate that even though the hydroforming process has been described as preferable in forming the lever assembly  100 , other similar tubular forming manufacturing processes such as by Thixomolding®, which is a registered trademark of Thixomat, Inc. of Ann Arbor, Mich., can be used in practicing the invention. Thixomolding® is the process of injection molding metal, such as eutectic magnesium or aluminum particles, to form metallic parts and is well known in the art. 
     As stated earlier, even though the invention has been described with a metal tube with an integral central portion  20  and an integral upper portion  30 , both of which are formed from a longitudinally extending, generally rectangular, thin wall cross-sectional configuration, the tube  10  can be formed into other cross-sectional shapes such as I-beam, box square, triangular, oval, round or polygonal as dictated by the design requirements of the application, without departing from the scope of the invention. 
     While the invention has been described for a particular embodiment, it will be evident to those skilled in the art that numerous variations of the details may be made without departing from the spirit and teachings of the invention as defined in the appended claims.