Abstract:
The present invention is directed to apparatus, systems, and methods for incorporating a master cylinder into a hydraulic brake system. An embodiment of the present invention includes a housing, a bore extending through the housing, a cover, and a groove formed in the cover. The housing includes a fluid reservoir formed therein. The bore is capable of supporting a movable piston to actuate the hydraulic braking system. The cover is secured to the housing and the groove in the cover descends away from the center of the cover such that the groove is capable of directing fluid away from the center of the cover.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The application claims priority from U.S. Provisional Patent Application No. 60/856,228, entitled “MASTER CYLINDER” and filed on Nov. 2, 2006, which is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is generally related to hydraulic brake system components, and more particularly, to master cylinders. 
       BACKGROUND 
       [0003]    Master cylinders are often designed for use with hydraulic braking systems for vehicles. Master cylinders are commonly incorporated into braking assemblies in a variety of vehicles such as, for example, towing trailers, motorcycles, and the like. In the trailer industry, master cylinders are incorporated into surge brake actuators for towing trailers to actuate the trailer&#39;s braking system when the towing vehicle pulling the trailer is braking or otherwise slowing. For example, when a vehicle towing a trailer slows or stops, the trailer surges forward with respect to the towing vehicle. A master cylinder mounted onto the trailer may sense the surging of the trailer and actuate the trailer&#39;s braking system to apply a braking force to the wheels of the trailer, thus slowing or stopping the trailer in coordination with the slowing or stopping of the towing vehicle. 
         [0004]    Master cylinders are important to the trailer industry because master cylinders facilitate the safe and effective operation of trailers being pulled by towing vehicles. Therefore, it is continuously desirable to develop novel apparatus, systems, and methods that improve upon master cylinders used in the trailer industry. 
       SUMMARY 
       [0005]    The present invention is directed to apparatus, systems, and methods for incorporating a master cylinder into a hydraulic brake system. An embodiment of the present invention includes a housing, a bore extending through the housing, a cover, and a groove formed in the cover. The housing includes a fluid reservoir formed therein. The bore is capable of supporting a movable piston to actuate the hydraulic braking system. The cover is secured to the housing and the groove in the cover descends away from the center of the cover such that the groove is capable of directing fluid away from the center of the cover. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0006]    In the accompanying drawings, which are incorporated in and constitute a part of this specification, embodiments of the invention are illustrated that, together with a general description of the invention given above and the detailed description given below, serve to illustrate the principles of this invention. The drawings and detailed description are not intended to and do not limit the scope of the invention or the claims in any way. Instead, the drawings and detailed description only describe embodiments of the invention, and other embodiments of the invention not described are encompassed by the claims. 
           [0007]      FIG. 1  illustrates a perspective view of a master cylinder. 
           [0008]      FIG. 2A  illustrates a perspective view of a cover of a master cylinder. 
           [0009]      FIG. 2B  illustrates a cross-sectional view of the cover of  FIG. 2A  taken generally along the line A-A. 
           [0010]      FIG. 3  illustrates an exploded view of a master cylinder. 
           [0011]      FIG. 4  illustrates a second exploded view of a master cylinder. 
           [0012]      FIG. 5  illustrates a perspective view of a housing of a master cylinder. 
           [0013]      FIG. 6A  illustrates a side view of a master cylinder having a decal. 
           [0014]      FIG. 6B  illustrates a cross-sectional view of the master cylinder of  FIG. 6A  taken generally along the line A-A. 
           [0015]      FIG. 6C  illustrates a magnified view of the interior of the reservoir of a master cylinder. 
           [0016]      FIG. 7  illustrates a perspective view of a pressure cup for a master cylinder. 
           [0017]      FIG. 8A  illustrates a perspective view of a spring for a master cylinder. 
           [0018]      FIG. 8B  illustrates a top view of the spring of  FIG. 8A  for a master cylinder. 
           [0019]      FIG. 9A  is a perspective view of a cap for a master cylinder. 
           [0020]      FIG. 9B  illustrates a side view of the cap of  FIG. 9A  for a master cylinder. 
           [0021]      FIG. 9C  illustrates a cross-sectional view of the cap of  FIG. 9B  taken generally along the line A-A. 
           [0022]      FIG. 10A  illustrates a perspective view of a cap for a master cylinder. 
           [0023]      FIG. 10B  illustrates a side view of the cap of  FIG. 10A  for a master cylinder. 
           [0024]      FIG. 10C  illustrates a cross-sectional view of the cap of  FIG. 10B  taken generally along the line B-B. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    While the present invention is described with reference to the embodiments described herein, it should be clear that the present invention should not be limited to such embodiments. Therefore, the description of the embodiments herein is illustrative of the present invention and should not limit the scope of the invention as claimed. As described herein, a master cylinder is generally implemented into a surge actuator for use with a towing trailer; however, upon understand the detailed description and accompanying figures, it will be readily understood by one of ordinary skill in the art that embodiments of the described and illustrated master cylinder may be incorporated into a variety of other vehicles to facilitate braking of such vehicles. 
         [0026]    Master cylinders may be designed to facilitate the braking of a trailer coupled to a towing vehicle. Typically, the braking systems of a towing vehicle are designed to slow and stop only the towing vehicle. It will readily be understood that as a towing vehicle slows or stops, it is advantage to provide apparatus, mechanisms or systems that also slow or stop a trailer being towed by the towing vehicle. Embodiments of the master cylinders described and disclosed herein may be designed to sense the slowing or stopping of a towing vehicle and apply a braking force to a trailer in proportion to the stopping or slowing of the towing vehicle. 
         [0027]      FIG. 1  illustrates an exemplary embodiment of a master cylinder  100 . The master cylinder  100  may be arranged to utilize the force of a slowing or stopping towing vehicle to actuate the braking system to slow or stop the towed vehicle. As illustrated in  FIG. 1 , a master cylinder  100  may include a cover  102 , a cap  104 , and a housing  105 . The master cylinder  100  may be constructed of metal, plastic or any other suitable material as will be appreciated by one of ordinary skill in the art. In an exemplary embodiment, the cover  102  and the housing  105  of the master cylinder  100  are manufactured or otherwise fabricated from a die cast metal, such as aluminum. Manufacturing such components from aluminum provides for durability and resistance to rust, oxidation, and other such corrosive effects. In another embodiment, the cover  102  of a master cylinder  100  may be manufactured or otherwise fabricated from a fiberglass or carbon fiber reinforced polymer, such as nylon or the like. 
         [0028]    As can be seen in  FIG. 1 , a master cylinder  100  may be arranged as a self-contained unit. Such an arrangement allows for master cylinder  100  to be incorporated, integrated, or otherwise attached to the braking system of a trailer regardless of the design of the trailer. 
         [0029]      FIGS. 2A and 2B  illustrate a perspective and a cross-sectional view of the cover  102 . The cover  102  includes a lip  106  that extends or rises above the upper surface of the cover  102  to define an access aperture or opening  107  passing through the cover  102 . In one embodiment, the extended or raised lip  106  may be positioned in the center of the cover  102 . As will be subsequently described, the extended lip  106  and cap  104  may be arranged such that the lip  106  may accept and reversibly secure the cap  104  to the cover  102  so as to close and seal the access opening  107 . The opening  107  is arranged such that when the cap  104  is not secured to the lip  106 , the opening  107  provides access to the housing  105  of the master cylinder  100 . Such access allows for hydraulic fluid, or other such liquids, to be deposited into the housing  105  or removed from the housing  105  through the opening  107 . 
         [0030]    The cap  104  may be selectively removed from the extended lip  106  to facilitate the pouring of fluid into the housing  105  and the removal of fluid from the housing  105  through the opening  107 . When an appropriate operational volume of fluid is deposited in the housing  105  or an appropriate volume of fluid is removed from the housing  105 , the cap  104  may be secured in the lip  106  to reseal the opening  107  and prevent fluid from leaking through the opening  107 . The cap  104 , extended lip  106 , and opening  107  may be generally circular in cross-sectional shape, or may be any shape that allows for reversible sealing of the opening  107 . 
         [0031]    The lip  106  may be arranged to facilitate the pouring of fluid into the housing  105  and to prevent contaminants from entering the housing  105 . For example, the lip  106  may serve as a raised filler lip onto which an operator may rest a fluid container used to pour fluid into the housing  105 . By using the lip  106  to rest a fluid container, an operator may more readily fill the housing  105  with fluid without concerns of spilling fluid onto the cover  102  or other exterior surfaces of the master cylinder  100 . In addition, the lip  106  may provider a barrier to prevent debris, dirt, or other such contaminants residing on the surface of the cover  102  from passing through the opening  107  and entering the master cylinder  100 . For example, when the cap  104  is removed from the extended lip  106  to allow fluid to be added, there is the possibility that contaminants residing on the surface of the cover  102  may flow into or otherwise enter the housing  105 . However, the lip  106  extends above the surface of the cover  102  to block the flow of such contaminants through the opening  107  and into the housing  105 . 
         [0032]    The cover  102  may also include a groove or channel  110  along the upper surface of the cover  102 . The groove  110  is arranged as a drainage groove to drain or otherwise move fluids and other substances away from the cover  102 . As will be readily understood, a master cylinder  100  that is coupled to a trailer is commonly exposed to the elements during normal operation. For example, the master cylinder  100  is commonly exposed to dirt, grease, moisture, and other such contaminants as a trailer is towed behind a towing vehicle. Such contaminants may settle on the surface of the cover  102  and may cause damage to the cover  102 , in the form of rust, oxidation, or other such corrosion, or may cause damage to internal components of the master cylinder  100  if allowed to enter the housing  105 . 
         [0033]    The drainage grooves  110  are arranged to prevent water and other such fluids that promote corrosion from settling on the cover  102 . The grooves  110  are angled, slanted, descended, or otherwise arranged to promote the flow of fluid and contaminants away from the opening  107  and to generally encourage fluids and contaminants to flow off the cover  102 . Such an arrangement is particularly affective in controlling moisture and contaminants when the cap  104  is removed from the extended lip  106  during regular maintenance, such as during the filling of the master cylinder  100  with fluid or the bleeding of pressure from the braking system. 
         [0034]    In one embodiment, the exterior surface of the cover  102  may be generally angled downward and away from the extended lip  106  to assist the grooves  110  in promoting the flow of fluids and other contaminants way from the opening  107 . Although the cover  102  as described and illustrated herein includes one drainage groove  110 , other embodiments may include a plurality of grooves or a system of grooves that include multiple legs or channels to promote the flow of fluid and other contaminants away from the opening  107  and off of the cover  102 . 
         [0035]      FIGS. 3 and 4  illustrate an exploded view of an exemplary embodiment of a master cylinder  100 . The housing  105  includes a fluid reservoir  120  with an opening at the top of the housing  105 . The housing  105  also includes a bore or chamber  123  formed through the housing  105 . The bore  123  is generally positioned below the reservoir  120  (as best seen in  FIG. 6B ) and a pair of bleed valves  119  provides a fluid path between the reservoir  120  and the bore  123 . The master cylinder  100  further includes a gasket  114  for sealing the interface between the cover  102  and housing  105  and a splashguard  118  positioned within the reservoir  120 . 
         [0036]      FIGS. 3 and 4  also illustrate a number of components that may be positioned within the bore  123 . For example, a bumper  128 , a check valve  130 , a compression spring  132 , a pressure cup  134 , a piston  140 , and a snap ring  142  may all be positioned within the bore  123  to facilitate the actuation of the trailer braking system. Specifically, the piston  140  is generally arranged to move back and forth along the axis of the bore  123  to actuate and disengages the trailer braking system. 
         [0037]    In addition, a dust boot  144  may be attached to an opening of the bore  123 . The dust boot  144  may prevent foreign particles, such as dirt, dust, grease, moisture, and the like from entering the bore  123  or fluid reservoir  120 . The piston  140  may compress the spring  132  to drive fluid through the pressure cup  134  and actuate the braking system of the trailer. The spring  132  may return the piston back to a “neutral” position in which fluid may again enter the bore  123 . The master cylinder  100  may be arranged such that the pressure within the master cylinder  100  selectively actuates and disengages the braking system of a trailer or other such towed vehicle. 
         [0038]    In an embodiment of a master cylinder  100 , the gasket  114  is seated or otherwise positioned between the cover  102  and the housing  105  prior to the assembly of the master cylinder  100 . The gasket  114  serves as a sealing member to seal the reservoir  120  formed by the assembly of the cover  102  to the housing  105 . The gasket  114  is arranged to prevent fluid within the reservoir  120  of the housing  105  from flowing through the interface between the cover  102  and the housing  105 . 
         [0039]    The cover  102  may be secured to the housing  105  through fasteners, such as screws, bolts, rivets, and the like (not shown). The cover  102  includes a plurality of fastener apertures  109  and the housing  105  includes a plurality of matching fastener apertures  112 . The fastener apertures  109  in the cover  102  are arranged to align with the fastener apertures  112  of the housing  105  such that when the cover  102  is fitted onto the housing  105 , fasteners may be passed through the aligned fastener apertures  109 ,  112  and be secured in the fastener apertures  112  of the housing  105 . Such an arrangement may secure the cover  102  to the housing  105 . The cover  102  may be attached to the housing  105  such that the attachment is reversible, or alternatively, the cover  103  may be attached to the housing  105  such that the attachment is not reversible. In one embodiment, the fastener apertures  112  of the housing  105  may be threaded such that threaded screws or bolts passing through the fastener apertures  109  of the cover  102  may be secured into the fastener apertures  112  of the housing  105  to secure the cover  102  to the housing  105 . 
         [0040]    The gasket  114  may include a plurality of apertures  116  that match and align with the fastener apertures  109 ,  112  of the cover  104  and housing  105 . In such an arrangement, the gasket  114  may be positioned between the cover  102  and the housing  105  to seal the interface without interfering with fasteners passed through the fastener apertures  109 ,  112  to secure the cover  102  to the housing  105 . The gasket  114  further includes an opening  115  coinciding with the access opening  107  in the cover  102 . The gasket opening  115  is arranged so as not to interfere with fluids passing through the access opening  107 , i.e., the gasket opening  115  does not interfere with the fluid communication between the access opening  107  and the fluid reservoir  120  located in the housing  105 . 
         [0041]    The cover  102  may also include a plurality of posts  108  extending downward from the fastener apertures  109 . The posts  108  may be arranged for mating engagement and alignment with the gasket apertures  116  and fastener apertures  112  of the housing  105 . Such an arrangement may maintain the alignment or orientation of the gasket  114  with respect to the cover  102  and housing  105  during and after assembly of the master cylinder  100 . Engagement of the posts  108  with the fastener apertures  112  of the housing also maintains the alignment or orientation of the cover  102  with respect to the housing  105  during and after assembly of the master cylinder  100 . Maintaining alignment and orientation of components reduces or eliminates issues of wear, leakage, or misalignment of the gasket  114 , cover  102 , housing  105 , and other such components of the master cylinder  100 . 
         [0042]    A coating or sealant may be applied to the gasket  114  prior to assembly of the master cylinder  100  to enhance the sealing capabilities of the gasket  114 . In one embodiment, an adhesive is applied to both sides of the gasket  114  to adhere or otherwise bond the gasket  114  to both the cover  102  and the housing  105  during and after assembly of the master cylinder  100 . Such an arrangement may enhance the seal provided by the gasket  114 , along with enhancing the durability and service life of the seal provided by the gasket  114 . Adhesives used in the assembly of the master cylinder  100  may be arranged to cure through the application of pressure. The tightening of fasteners coupling the cover  102  to the housing  105  may generate the appropriate pressure needed to cure adhesives. 
         [0043]    In another embodiment, the adhesive may be arranged to provide a bond that allows for disassembly of the master cylinder  100  without damaging the gasket  114 , cover  102 , or housing  105 . In one example, the adhesive may be selected such that the bond created by the adhesive is loosened or broken by the application of a chemical that does not affect the gasket  114  or other master cylinder components. In another example, the adhesive may be selected such that the bond created by the adhesive is sufficient to enhance the sealing ability of the gasket  114 , yet may still allow for separation of the gasket  114  from the cover  102  and housing  105  through the application of non-destructive mechanical force. 
         [0044]    In another embodiment, a gap filler may be applied to both sides of the gasket  114 . A gap filler may enhance the seal of the gasket  114  by filling gaps between the gasket  114  and the cover  102  and housing  105 ; however, the gap filler may not include any adhesive properties. In such an arrangement, the seal is enhanced without substantially affecting the disassembly of the master cylinder  100 . Although the embodiments described include adding a coating to both sides of the gasket  114 , it will be readily understood that a coating may be applied to only one side of a gasket  114  or may be applied directly to the cover  102  or housing  105  to enhance the seal between the cover  102  and housing  105 . It will also be appreciated that the application of adhesives further forms a master cylinder  100  that is a fully self-contained and separate unit that may be assembled with or other wise utilized by a wide variety of trailers. 
         [0045]    With further reference to  FIGS. 3 and 4 , the master cylinder  100  includes a splashguard  118 . The splashguard  118  is positioned within the reservoir  120  and generally located below the access opening  107  in the cover  102 . The splashguard may be utilized as a fluid deflection member to facilitate operation or maintenance of the master cylinder  100 . In one embodiment of the master cylinder  100 , pressure in brake lines attached to the master cylinder  100  may be relieved to optimize the performance of the braking system. The pressure may be commonly relieved through bleed valves  119  located in the bottom of the reservoir  120 . The splashguard  118  is generally positioned such that the splashguard  118  blocks the path between the bleed valves  119  and the access opening  107  in the cover  102 . 
         [0046]    The reservoir  120  generally contains brake fluid, or other similar hydraulic fluids. When pressure is bled from the brake lines into the reservoir  120 , the fluid in the reservoir  120  may be disturbed. Such disruption often causes fluid to flow upward towards the access opening  107 . The splashguard  118  is positioned and arranged to deflect such upwardly flowing fluid to minimize or prevent the fluid from flowing to and through the access opening  107  during bleeding of the brake lines. 
         [0047]    As illustrated in  FIG. 5 , in an embodiment of a master cylinder the housing  105  may have baffles  122  along the sides of the reservoir  120  for retaining and aligning the splashguard  118 . In the exemplary embodiment illustrated in  FIGS. 3 and 4 , the splashguard  118  includes a pair of tabs  121  that extend upward from a fluid deflection body portion  117  of the splashguard  118 . The tabs  121  are sized to slide into and be secured by the baffles  122 . The tabs  121  are also sized such that when the tabs  121  are positioned in the baffles  122  and the master cylinder  100  is assembled, the cover  102  contacts the top portions of the tabs  121  to further secure or maintain the positioning of the tabs  121  in the baffles  122 . 
         [0048]    The tabs  121  and body  117  of the splashguard  118  are arranged such that when the tabs  121  are secured in the baffles  122 , the body  117  is appropriately positioned to deflect fluid disturbed by bleeding the brake lines from splashing through the access opening  107 . Although an embodiment of the splashguard  118  is described and illustrated herein as having a body  117  and a pair of tabs  121 , it will be readily appreciated by one of ordinary skill in the art that a splashguard  118  may be of any other appropriate shape or position that blocks the fluid paths from the bleed valves  119  to the access opening  107 . The splashguard  118  is preferably made out of stainless steel to resist rust or other such corrosion, but may also be manufactured or otherwise fabricated from any other material suitable for contact with hydraulic fluid and capable of deflecting disturbed fluid. 
         [0049]    In addition to deflecting fluid during bleeding of brake lines, the splashguard  118  may deflect fluid disturbed by movement of the piston  140  within the master cylinder to prevent such fluid from flowing out of the access opening  107 . It will also be understood that the splashguard  118  may be arranged to be retained within the reservoir  120  without use of the baffles  122 . In one example, the splashguard  118  may be shaped or bent in such a manner so as to be self-retained within the reservoir  120 . 
         [0050]      FIGS. 3 and 4  illustrates a reservoir fitting  126  that is connected to the reservoir  120  through an aperture  127  in the side of the reservoir  120 . The reservoir fitting  126  may be removably secured to the aperture  127  of the reservoir  120  to facilitate reverse lockout solenoid retrofitting. 
         [0051]    The cap  104  and the extending lip  106  may each include mating threads such that the cap  104  may be reversibly secured to the lip  106  by engaging the mating threads and twisting or otherwise turning the cap  104  with respect to the lip  106 . In one embodiment, the threads of the cap  104  are located on an outside surface of the cap and the threads of the lip  106  are located on an inside surface of the lip  106 . In such an arrangement, the cap  104  is positioned and secured within the lip  106  to seal the access opening  107  against leakage of fluid from the reservoir  120 . In another embodiment, the threads of the cap  104  are located on an inside surface of the cap  104  and the threads of the lip  106  are located on an outside surface of the lip  106 . In such an arrangement, the lip  106  is positioned and secured within the cap  104  to seal the access opening  107  against leakage of fluid from the reservoir  120 . 
         [0052]    It will be readily appreciated that embodiments as described herein provide for the cap  104  to be reversibly secured to the cover  102 . Such arrangements allow for the cap  104  to be removed from the cover  102  for system functions such as filling the reservoir  120  with a fluid, venting the reservoir  120 , bleeding the braking system, and the like. The cap  104  may include features on the exterior surfaces of the cap  104  to facilitate manually gripping the cap  104 . The cap  104  may further include a diaphragm  154  and a radial seal to further facilitate the sealing of the access opening  107  with the cap  104 . 
         [0053]    In an embodiment, the threads on the cap  104  and the threads of the lip  106  may both be relatively coarse threads. In such an arrangement, rotating or twisting the cap  104  into the extended lip  106  results in a relatively large vertical displacement with respect to the amount the cap  104  is turned. Such relatively large vertical displacements may provide a more user-friendly arrangement than a cap with fine threads. In addition, course threads are generally more durable and more resistant to stripping or other such deformations due to repeated use as compared to fine threads. In an embodiment, the threads are arranged such that a quarter-turn, i.e., rotating the cap  104  through ninety degrees of rotation, moves the cap  104  from a fully engaged and sealed position to an disengaged position where the cap  104  may be removed from the cover  102 . 
         [0054]    In an embodiment, a master cylinder  100  may include a decal  146  attached to an exterior surface of the master cylinder  100 . In one example, as seen in  FIGS. 4 and 6A , a decal  146  is adhered or otherwise attached to the outside of the housing  105 . In addition, such a decal  146  may be adhered to the cover  102 , cap  104 , or elsewhere on the master cylinder  100 . The decal  146  may include information to facilitate the use and operation of the master cylinder  100 . For example, the decal  146  may include information relating to the manufacture of the master cylinder  100 ; information relating to the type of brake assembly connected to the master cylinder  100 , for example “disc” or “drum” brakes; information relating to inspection or repair of the master cylinder  100 ; and the like. The decal  146  may also be used to customize the master cylinder  100  with company, brand, or product logos and information.  FIG. 6A  illustrates an embodiment of the decal  146  displaying the type of braking assembly connected to the master cylinder  100 , i.e., “disc” brakes. The indicia representing the information may be printed, imaged, inked, engraved, or otherwise affixed onto the decal  146 . 
         [0055]    In another embodiment, information may be molded, embossed or otherwise incorporated into components of the master cylinder  100 . In one example, as illustrated in  FIG. 9A , the cap  104  may be molded such that markings  158  are incorporated into the cap  104 . Such markings  158  may represent information that aids in managing inventory and facilitating the identification of master cylinders and actuators. Similar to the decal  146  described above, the markings  158  may include information relating to the manufacture of the master cylinder  100 ; information relating to the type of brake assembly connected to the master cylinder  100 , for example “disc” or “drum” brakes; information relating to inspection or repair of the master cylinder  100 ; and the like. The markings  158  may also be used to customize the master cylinder  100  with company, brand, or product logos and information. 
         [0056]      FIG. 6B  illustrates a cross-sectional view of the master cylinder  100  taken generally along line A-A of  FIG. 6A .  FIG. 6B  illustrates the interaction of the piston  140 , the spring  132  and the pressure cup  134 . In an embodiment, the piston  140  is moved to compress the spring  132 , which forces fluid out of the pressure cup  134 , to engage the brakes of a trailer. The spring  132  may force the piston  140  away from the pressure cup  134  to disengage the brakes. 
         [0057]    Also as illustrated in  FIG. 6B  and the magnified view of  FIG. 6C , the reservoir  120  may have raised bosses  124  around the bleed valves  119  located along the bottom of the reservoir  120 . In such an embodiment, the bosses  124  may be arranged to limit or prevent dirt, debris, and such contaminants from entering the braking system. For example, the bosses  124  may block contaminants that are floating in fluid in the reservoir  120  from entering the braking system, where such contaminants may cause damage to the system. 
         [0058]    An exemplary embodiment of the pressure cup  134  is illustrated in  FIG. 7 . The pressure cup  134  may include a plurality of apertures  138  passing through a top portion  136  of the pressure cup  134 . Such apertures  138  may be arranged in a symmetrical manner about a center of the pressure cup  134 . Alternatively, the apertures  138  may be arranged in any other that allows for fluid communication between the master cylinder  100  and the braking system. 
         [0059]    An exemplary embodiment of the spring  132  is illustrated in  FIGS. 8A and 8B . The spring  132  may have a top surface  150  having an aperture  152  therethrough. The aperture  152  may allow for fluid communication between the reservoir  120  and the pressure cup  134 . The fluid may pass through the aperture  152  of the spring  132  and into the pressure cup  134  to actuate the brake assembly. 
         [0060]    An exemplary embodiment of the cap  104  is illustrated in  FIGS. 9A ,  9 B and  9 C. Similar to previous descriptions, the cap  104  may be a quarter twist cap that facilitates a user quickly and easily removing of the cap  104  from the cover  102  and the user quickly and easily returning the cap  104  to the cover  102  to reseal the master cylinder  100 . A quarter twist cap  104  that includes course threads eases assembly by eliminating awkward fine threads that often cross thread or mismatch. The cap  104  may also include a radial seal and pressure-normalizing diaphragm  154  that further reduces or eliminates leaks at the caps  104 . The diaphragm  154  may be manufactured or otherwise fabricated from rubber or any other material capable of reducing or eliminating leaks. As best seen in  FIGS. 9B and 9C , the cap  104  also includes a vent hole  148 . The vent hole  148  allows the reservoir  120  and cap  104  to vent to the atmosphere. The cap  104  also includes an o-ring  156  to assist in securing and sealing the cap  104  to the cover  102 . 
         [0061]    Another exemplary embodiment of a cap  204  is illustrated  FIGS. 10A ,  10 B and  10 C. The cap  204  includes a low profile. The low profile may facilitate attaching the master cylinder  100  to a variety of trailers. The low profile may limit the interference between the master cylinder  100  and trailers as the master cylinder  100  is attached or secured to trailers. The cap  204  includes a radial seal and pressure-normalizing diaphragm  254  that further reduces or eliminates leaks at the caps  204 . The diaphragm  254  may be manufactured or otherwise fabricated from rubber or any other material capable of reducing or eliminating leaks. As best seen in  FIGS. 10B and 10C , the cap  204  also includes a vent hole  248 . The vent hole  248  allows the reservoir  120  and cap  204  to vent to the atmosphere. The cap  204  also includes an o-ring  256  to assist in securing and sealing the cap  204  to the cover  102 . The cap  204  includes a par of protrusions  260  to assist a user in twisting the cap  204  onto and off the cover  102 . 
         [0062]    With further reference to  FIG. 10A , the cap  204  may also include embosses, markings, or the like  258  to help aid in inventory and make identification of the master cylinder  100  and actuator quick and easy. Such markings  258  may include information relating to the manufacture of the master cylinder  100 ; information relating to the type of brake assembly connected to the master cylinder  100 , for example “disc” or “drum” brakes; information relating to inspection or repair of the master cylinder  100 ; or the like. The markings  258  may also be used to customize the master cylinder  100  with company or product logos and information. 
         [0063]    The invention has been described above and, obviously, modifications and alternations will occur to others upon a reading and understanding of this specification. The claims as follows are intended to include all modifications and alterations insofar as they come within the scope of the claims or the equivalent thereof.