Abstract:
A rotor puller has two arm members, ending at claws, and a jack with an extendible piston. The arm members and the jack are pivotably attached together about a pivot axis. Springs bias the arm members toward each other. The claws are placed over a brake rotor and retained thereon by a pin. After the claws have been placed, the jack is centered and activated to extend the piston towards the claws. The piston forcibly engages a wheel hub while the claws forcibly engage the rotor, pulling it from the wheel hub. Handles on the arm members facilitate placement of the claws over the rotor.

Description:
FIELD OF THE INVENTION 
   The present invention is a puller for removing an object from a shaft on which it is mounted, and more particularly for a puller that is well suited for use removing a vehicle brake rotor from a wheel hub. 
   BACKGROUND OF THE INVENTION 
   Vehicle disk brakes employ a rotor surrounding each wheel hub as a friction surface that is engaged by calipers to apply a braking force to a wheel mounted on the wheel hub. These rotors become worn with prolonged use and periodically need to be replaced. When the rotor has become so worn as to require replacement, it is frequently found to be affixed to the wheel hub by dirt and corrosion, making removal of the rotor difficult. A device for mechanically forcing the rotor from the hub is desirable to facilitate removal. 
   A classic device for removing an object from a shaft is known as a gear puller, which employs two or more arm members that engage a shaft-mounted gear, and an extendible member that engages the shaft. A screw mechanism forces the extendible member toward the gear, and the engagement of the arm members with the gear causes the gear to be forced to the end of the shaft. If the extendible member has a terminal portion with a diameter less than that of the shaft, the gear can be further forced to remove it from the shaft. 
   One early mechanical wheel puller is taught in U.S. Pat. No. 3,337,943, which teaches a wheel puller having an overall configuration similar to a classical gear puller, but with a hydraulic piston replacing the screw mechanism. The puller has a hydraulic cylinder with an extendible ram and two pivotably attached and opposed claws. In use, the claws are placed behind the wheel, pulley, or similar shaft-mounted object, while the ram is placed against the end of the shaft. The cylinder is then operated to extend the ram toward the ends of the claws, which causes the claws to forcibly engage and remove the wheel or pulley from the shaft. Similar hydraulic pullers are taught in U.S. Pat. Nos. 1,581,057; 1,777,616; 2,003,648; 2,003,756; 2,262,969; 5,159,743; 5,167,057; 5,233,740; 5,419,027; and 5,896,639. These devices require considerable care and effort in correctly placing the arm members to engage the shaft-mounted object as the extendible member is extended. Correct placement of the arm members is further complicated in the case of vehicle brake rotors, since these rotors typically are recessed in a wheel well of the vehicle and there is typically surrounding structure, such as brake calipers, that severely limits access to the rotor. 
   U.S. Pat. Nos. 3,069,761 and 3,908,258 teach hydraulic pullers with arm members which have adjustment mechanisms to assist in placing the arm members into the proper position for engagement with a shaft-mounted object. However, in both devices the adjustment mechanism is bulky and would not appear to be suitable for use where clearances are limited, such as for use removing vehicle brake rotors. 
   Thus, there is a need for a puller which facilitates placement of the pivoting members with respect to the rotor, even in situations where clearance about the rotor is limited. 
   SUMMARY OF THE INVENTION 
   The rotor puller of the present invention facilitates removing a brake rotor from a wheel hub of a vehicle onto which the brake rotor is mounted. The rotor puller has a pair of arm members with claws for engaging the brake rotor and a jack with an extendible piston for engaging the wheel hub. 
   The arm members each terminate at an arm base end and an arm work end. The arm base ends of the arm members are pivotably attached with respect to each other about a pivot axis, while the arm work ends each terminate at one of the claws. 
   Spring means for biasing the arm members together are provided. The spring means are preferably provided by a pair of arm springs which are mounted between the arm members at a location between the arm base ends and the arm work ends such that the arm springs are tensioned when the arm members are pivoted apart. 
   The jack is pivotably connected to the arm members so as to pivot with respect thereto about the pivot axis. Thus, when the claws of the arm members are engaged with the brake rotor, the jack can be pivoted to align it with the wheel hub. Preferably, a pivot handle is connected to the jack to facilitate adjusting its inclination with respect to the arm members. 
   Preferably, each of the arm members has an arm handle for grasping by the user to facilitate moving the arm members against the bias of the spring means. The arm handles preferably extend substantially parallel to the pivot axis, and are set back somewhat from the claws to facilitate placing the claws over the brake rotor when clearance about the brake rotor is limited. An arm stop is preferably mounted to one of the arm members and configured to engage the other so as to limit the minimum separation between the arm members. 
   The claws are configured to be forcibly engageable with the brake rotor. Typically, the brake rotor has a rotor rear surface that is planar, in which case each claw has a claw surface which faces the arm base end. Thus, when the claws are placed over the brake rotor, the claw surfaces are opposed to the rotor rear surface. 
   While the force of the spring means is typically sufficient to hold the claws in place on the rotor, for more positive retention it is preferred for one of the claws to have a pin passage therethrough that is spaced apart from the claw surface a sufficient distance to accommodate the thickness of the brake rotor. A retainer pin can be inserted into the pin passage to trap the brake rotor between the retainer pin and the claw surface to help maintain the claws in position on the brake rotor while the jack is operated. 
   When the jack is activated, the piston of the jack extends away from the pivot axis, toward the claws. To retract the piston after it has been extended, it is preferred to provide piston return means, such as one or more piston return springs that are tensioned as the piston is extended. It is also preferred to provide means for maintaining the pivotal position of the jack with respect to at least one of the arm members, to keep the jack in alignment while the operator is free to activate the jack to extend the piston. 
   To prevent damage to the wheel hub, it is preferred to mount a hub adapter onto the piston that is configured for engaging the specific style of wheel hub. The piston can be provided with an adapter mount that allows various hub adapters to be mounted to match the vehicle from which the rotor is being removed. 
   To place the rotor puller in position to remove the brake rotor, the arm members are separated against the bias of the spring means and the claws are passed over the rotor. The arm members are then allowed to come together until the claws springably engage the brake rotor, with the claw surfaces opposed to a back surface of the brake rotor. If a retainer pin is employed, it is inserted to positively maintain the claws engaged with the brake rotor. 
   After the claws have been engaged with the brake rotor, the jack is aligned with the wheel hub. The jack is activated to extend the extendible piston. When the piston extends sufficiently far, it engages the wheel hub. Further extension of the piston brings the piston into forcible engagement with the wheel hub and the claw surfaces of the claws into forcible engagement with the back surface of the brake rotor, at which time further extension of the piston acts to force the rotor off the wheel hub. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
       FIG. 1  is an exploded isometric view illustrating the elements of a rotor puller that forms one embodiment of the present invention. The rotor puller has a pair of arm members which, when the rotor puller is assembled, are pivotably attached with respect to each other. The arm members terminate at claws configured to be forcibly engageable with a brake rotor (shown in  FIGS. 3–5 ). The arm members each rotatably engage a pivot shaft that defines a pivot axis, and arm springs serve to bias the arm members together. A jack is mounted on the pivot shaft such that the jack can be pivoted relative to the arm members about the pivot axis by means of a shaft handle affixed to the pivot shaft. The jack has an extendible piston that can be forcibly extended toward the claws, and piston return springs that bias the piston away from the claws. 
       FIG. 2  is an assembled view of the rotor puller shown in  FIG. 1  where the arm members have been pivoted apart to allow the claws to be placed over the brake rotor (shown in phantom). The arm members each have an arm handle affixed thereto. The arm handles extend substantially parallel to the pivot axis, and allow a user to readily separate the arm members against the bias of the arm springs. The arm members each have a base crossbar, to which one of the piston return springs is connected, a mid crossbar, to which the arm springs are connected, and a claw plate, on which the claw is formed. A locking nut is provided that threadably engages the pivot shaft. A lock nut handle is affixed to the locking nut to allow the user to tighten the locking nut on the pivot shaft to lock the claws and the jack against pivoting when they are in a desired orientation. A hub adapter has been mounted onto the extendible piston of the jack, the hub adapter being designed to engage a wheel hub about which the brake rotor is mounted. 
       FIG. 3  illustrates the rotor puller shown in  FIGS. 1 and 2  when the arm members have been released to allow the claws to springably engage the brake rotor. Once so positioned, a retaining pin is inserted into one of the claws to maintain the claws engaged with the rotor. 
       FIG. 4  is an isometric view showing the rotor puller shown in  FIGS. 1–3  in the same position as shown in  FIG. 3 , but from a different angle to more clearly show the wheel hub and the brake rotor. The arm springs have been omitted to more clearly show the piston. As shown in  FIG. 4 , the jack has not yet been activated to extend the piston. 
       FIG. 5  is an isometric view of the rotor puller shown in  FIGS. 1–4  from the same angle as shown in  FIG. 4 , but where the jack has been activated to extend the piston toward the claws. The piston forcibly engages the wheel hub and causes the claws to forcibly pull the rotor from the wheel hub. The extension of the piston places the piston return springs in tension. 
       FIG. 6  is an isometric view of the rotor puller shown in  FIGS. 1–5  from the same angle as shown in  FIGS. 4 and 5 , after the brake rotor (shown in phantom) has been removed from the wheel hub. The fluid pressure in the jack has been released, allowing the piston return springs to retract the piston. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  is an exploded isometric view of a rotor puller  100  that forms one embodiment of the present invention. The rotor puller  100  is shown assembled in  FIGS. 2–6 . 
   The rotor puller  100  has a first arm member  102  and a second arm member  104  that are pivotably connected together when the rotor puller  100  is assembled. The first arm member  102  is formed by a pair of parallel first arm bars  106 , each terminating at a first arm bar base end  108 , having a first arm pivot passage  110  therethrough, and a first arm bar work end  112 . The first arm bars  106  are joined together by a first arm member base crossbar  114 , a first arm member mid crossbar  116 , and a first claw plate  118  that joins the first arm bars  106  together at their first arm bar work ends  112 . The first claw plate  118  is configured to provide a first claw  120  that is positioned to forcibly engage a brake rotor  122  (shown in  FIGS. 3–5  and shown in phantom in  FIGS. 2 and 6 .) 
   The second arm member  104  is similar in construction to the first arm member  102 , and has a pair of parallel second arm bars  124  that each terminates at a second arm bar base end  126 , having a second arm pivot passage  128  therethrough, and a second arm bar work end  130 . The second arm bars  124  are joined together by a second arm member base crossbar  132 , a second arm member mid crossbar  134 , and a second claw plate  136  that joins the second arm bars  124  together at their second arm bar work ends  130 . The second claw plate  136  is configured to provide a second claw  138  that is positioned to forcibly engage the brake rotor  122 . 
   The first arm member base crossbar  114 , the first arm member mid crossbar  116 , and the first claw plate  118  are somewhat longer than the second arm member base crossbar  132 , the second arm member mid crossbar  134 , and the second claw plate  136 , such that the separation between the first arm bars  106  is sufficient to accommodate the second arm member  104  residing therebetween, as better shown in  FIGS. 2–6 . The first arm member  102  and the second arm member  104  are connected together by a pivot shaft  140  that passes through and rotatably engages the first arm pivot passages  110  in the first arm bar base ends  108  and through the second arm pivot passages  128  in the second arm bar base ends  126 . The pivot shaft  140  defines a pivot axis  142  about which the arm members ( 102 ,  104 ) rotate. An arm stop  144  is affixed to one of the second arm bars  124  near the second arm bar base end  126 . The arm stop  144  is positioned to engage one of the first arm bars  106  to limit the minimum angle between the arm members ( 102 ,  104 ). 
   A pair of arm springs  146  are attached between the first arm member mid crossbar  116  and the second arm member mid crossbar  134 . The arm springs  146  are tensioned when the arm members ( 102 ,  104 ) are pivoted apart (as shown in  FIG. 2 ), the spring tension serving to bias the arm members ( 102 ,  104 ) toward each other. 
   It is preferred to provide a first arm handle  148  attached to the first arm member  102  and a second arm handle  150  attached to the second arm member  104 . The first arm handle  148  is mounted to one of the first arm bars  106  and extends parallel with the pivot axis  142 . Similarly, the second arm handle  150  is mounted to one of the second arm bars  124  and also extends parallel with the pivot axis  142 . Preferably, the first arm handle  148  is positioned above the first arm member  102 , while the second arm handle  150  extends outwardly from the second arm member  104 , to facilitate placing the rotor puller  100  onto the brake rotor  122  in the orientation shown. This facilitates the operation of a jack  152  by the user after the rotor puller  100  has been placed on the brake rotor  122 . 
   The jack  152  has a jack body  154  that is mounted to the pivot shaft  140  on which the arm members ( 102 ,  104 ) are pivotably mounted. The jack  152  has a piston  156  that extends from the jack body  154  and terminates at a piston end  158 . A pump handle  160  and a pressure release knob  162  are mounted on the jack body  154 . When the pressure release knob  162  is in a closed position, the pump handle  160  can be operated to forcibly extend the piston  156  from the jack body  154 , moving the piston end  158  toward the claws ( 120 ,  138 ), as shown in  FIG. 5 . 
   When the pressure release knob  162  is turned to an open position, pressure resulting from operation of the pump handle  160  is released, and the piston  156  may be retracted away from the claws ( 120 ,  138 ). In the rotor puller  100 , two piston return springs  164  are each connected between the piston end  158  and one of the arm member base crossbars ( 114 ,  132 ), as best shown in  FIG. 2 . When the piston  156  is extended, the piston end  158  moves toward the claws ( 120 ,  138 ) and away from the arm member base crossbars ( 114 ,  132 ), tensioning the piston return springs  164 . When the pressure release knob  162  is turned to the open position, as shown in  FIG. 6 , the tension of the piston return springs  164  acts to retract the piston  156 , retracting the piston end  158  toward the arm member base crossbars ( 114 ,  132 ). 
   As shown in  FIG. 1 , the jack body  154  in this embodiment has a jack passage  166  with a key surface  168 . The jack passage  166  slidably engages the pivot shaft  140 , which is provided with a key flat  170  that engages the key surface  168  to prevent rotation between the jack body  154  and the pivot shaft  140 . A pivot handle  172  is mounted to a pivot handle block  174  on one end of the pivot shaft  140 . The pivot handle  172  allows an operator to readily adjust the pivotal orientation of the jack  152  relative to the arm members ( 102 ,  104 ). The pivot handle  172  is preferably mounted to the pivot handle block  174  so as to rotate about a shaft handle axis  176  that is normal to the pivot axis  142 , allowing it to be folded alongside the arm members ( 102 ,  104 ) for compact storage of the rotor puller  100 . For the same reason, it is preferred for the pump handle  160  to be removable. 
   The pivot shaft  140  is also provided with a threaded portion  178 . A locking nut  180  is threadably engaged with the threaded portion  178  of the pivot shaft  140 . When the locking nut  180  is tightened on the threaded portion  178 , it forcibly compresses the first arm member  102 , the second arm member  104 , and the jack body  154  between the locking nut  180  and the pivot handle block  174  to lock the first arm member  102 , the second arm member  104 , and the jack body  154  together. When tightened, the locking nut  180  provides means for maintaining the pivotal position of the jack  152  with respect to the arm members ( 102 ,  104 ). Preferably, a locking nut handle  182  is attached to the locking nut  180  to allow the operator to tighten the locking nut  180  without the use of tools. 
   The piston end  158  is provided with an adapter mount  184  (shown in  FIG. 1 ), onto which a hub adapter  186  (shown in  FIGS. 2–6 ) can be releasably mounted. The adapter mount  184  is preferably a ½″ square drive stub to allow a conventional axle nut socket to be mounted to serve as the hub adapter  186 . 
   As illustrated, the brake rotor  122  has a planar rotor rear surface  188  (shown in  FIG. 3 ). To forcibly engage the rotor rear surface  188 , the first claw  120  is formed with a first claw surface  190  (shown in  FIG. 6 ) that faces the first arm bar base ends  108 . Similarly, the second claw  138  is formed with a second claw surface  192  (also shown in  FIG. 6 ) that faces the second arm bar base ends  126 . When the rotor puller  100  is placed over the brake rotor  122  (as shown in  FIGS. 2–6 ), the first claw surface  190  and the second claw surface  192  are opposed to the rotor rear surface  188 . 
   One of the claw plates ( 118 ,  136 ) is preferably provided with a retaining pin passage  194  therethrough, into which a retaining pin  196  can be inserted. In the rotor puller  100 , the retaining pin passage  194  passes through the first claw plate  118 , and is spaced apart from the first claw surface  190  a sufficient distance to accommodate the brake rotor  122  between the first claw surface  190  and the retaining pin  196 . 
     FIGS. 2–6  illustrate the rotor puller  100  at various sequential stages as it is employed to remove the brake rotor  122  from a wheel hub  198  (both of which are shown in phantom in  FIG. 2 ). As shown in  FIG. 2 , the hub adapter  186  is mounted onto the adapter mount  184  of the piston end  158 . The hub adapter  186  is selected to mate with the specific model of the wheel hub  198  and is designed to forcibly engage the wheel hub  198  without causing damage. As noted above, the hub adapter  186  can typically be provided by a conventional axle nut socket that is designed for removing an axle nut to remove the wheel hub  198  from an axle (not shown) on which it is mounted. Alternatively, the hub adapter  186  can be any appropriate form of ram that is configured to forcibly engage surfaces of the wheel hub and/or the end of the axle while remaining small enough to allow the brake rotor  122  to be passed thereover, and which is provided with a socket shaped to accept the adapter mount  184  therein. 
   The user grasps the first arm handle  148  and the second arm handle  150  and pivots the first arm member  102  and the second arm member  104  apart, against the bias of the arm springs  146 . The first arm member  102  and the second arm member  104  are separated until the first claw plate  118  and the second claw plate  136  can be passed over the brake rotor  122 , as shown in  FIG. 2 . The first arm member  102  and the second arm member  104  are then allowed to pivot toward each other until the claw plates ( 118 ,  136 ) engage either the brake rotor  122  or the wheel hub  198 , as shown in  FIGS. 3 and 4  (the arm springs  146  are omitted in  FIGS. 4–6  for clarity). As noted above, in this position, the first claw surface  190  and the second claw surface  192  face the rotor rear surface  188  of the brake rotor  122 . 
   At this time, the retaining pin  196  is inserted into the retaining pin passage  194  in the first claw plate  118 , trapping the brake rotor  122 . As noted above, the retaining pin passage  194  is spaced apart from the first claw surface  190  sufficiently to accommodate the brake rotor  122 . Together with the tension resulting from the arm springs  146 , the retaining pin  196  maintains the rotor puller  100  in position on the brake rotor  122 , freeing the hands of the user. The user then uses the pivot handle  172  to align the jack  152  with the wheel hub  198 . The locking nut  180  is tightened once the jack  152  has been properly aligned. 
   Once the jack  152  is aligned with the wheel hub  198  and locked in position, the user makes certain that the pressure release knob  162  is turned to its closed position and operates the pump handle  160  to forcibly extend the piston  156  from the jack body  154 . As the piston  156  extends, the hub adapter  186  is brought into forcible engagement with the wheel hub  198 . Further extension of the piston  156  causes the claw surfaces ( 190 ,  192 ) to forcibly engage the rotor rear surface  188  of the brake rotor  122 , and this forcible engagement causes any continued extension of the piston  156  to force the brake rotor  122  from the wheel hub  198 , as shown in  FIG. 5 . Once the brake rotor  122  has been removed from the wheel hub  198 , the pressure release knob  162  is turned to the open position, allowing the piston return springs  164  to retract the piston  156  to the position shown in  FIG. 6 . The pressure release knob  162  may then be turned to the closed position to ready the rotor puller  100  for another removal operation. 
   While the novel features of the present invention have been described in terms of particular embodiments and preferred applications, it should be appreciated by one skilled in the art that substitution of materials and modification of details obviously can be made without departing from the spirit of the invention.